ML21356B710

Orano Tli, Application for Certificate of Compliance for the Versa-Pac Shipping Package Amendment, Revision 13

ML21356B710
Person / Time
Site:	07109342
Issue date:	12/31/2021
From:	Orano TLI
To:	Office of Nuclear Material Safety and Safeguards
Shared Package
ML21356B707	List: ML21356B708 ML21356B709 ML21356B710
References
LTR-20000-160-01
Download: ML21356B710 (532)

Text

ORANO TLI Fulton, MD Application for Certificate of Compliance for the Versa-Pac Shipping Package NRC Certificate of Compliance USA/9342/AF-96 Docket 71-9342 REVISION 13 DECEMBER 2021

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Record of Revisions - Revision 13 (December 2021)

Official approval of Versa-Pac SAR Revision 13: DCN-21-003 General

• All headers changed to new Orano TLI logo.

• Starting with Revision 13, the revision listed in the header of all pages is the latest revision and revision bars from prior revisions are no longer retained. As a result, the List of Effective Pages has been removed.

Licensing Drawing Revisions Descriptions in Proprietary SAR Version Chapter 1

• §1.1 Added High-Capacity Basket, dual 5-inch pipe limit for 20-wt% contents to Table 1-4. Added sentence clarifying that 1S and 2S cylinders must be compliant with the version of the ANSI N14.1 standard effective at the time of fabrication.

• §1.2.2 Added mention of High-Capacity Basket contents.

• §1.3 Changed ANSI N14.1 reference to Latest Revision".

• §1.4.1 VP-55-LD updated to Revision 5

• §1.4.2 Removed enamel from topcoat requirement.

• §1.4.3 Added FAR 25.853 as a permissible flame retardancy specification requirement.

• §1.4.8 and §1.4.9 Added for the new High-Capacity Basket description and Licensing Drawing.

Chapter 2

• §2.1.2 removed wording indicating that the Versa-Pac has a 10 year design lifetime

• Changed §2.12 to Appendices to match Reg Guide 7.9 format. References shifted to Section

§2.12.1

• §2.6 and §2.7 added reference to Appendix 2.12.3 for HCB analysis

• §2.12.1 added new references for HCB analysis

• §2.12.2 added to include VP-55 LS-DYNA analysis

• §2.12.3 added to include the HCB stress analysis Chapter 3

• §3.1.3.2 year 2012 removed from ANSI N14.1 reference.

• Table 3-10 Reference [2] year 2012 removed from ANSI N14.1 reference.

• Section 3.5 listed new appendix 3.5.4, classical equations appendix changed to 3.5.5

• Section 3.5.1 changed reference [2] to Latest Revision and added references [17] through [19]

• §3.5.2 year 2012 removed from ANSI N14.1 reference.

• §3.5.4 added appendix for HCB thermal analysis.

• §3.5.5.2.1 updated table numbering due to added HCB appendix.

i

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Record of Revisions - Revision 13 (December 2021)

Chapters 4 & 5

• No Changes Chapter 6

• Frontmatter Tables of Contents, Tables, and Figures updated

• §6.1.1.4 Added to discuss the addition of the High-Capacity Basket (HCB)

• §6.1.2.6 Added to provide HCB criticality analysis summary

• §6.1.2.7 Updated to correct existing USLs, based on changes to Section 6.8 (see below) and added HCB USL. Note: the USL changes have no effect on the Versa-Pac criticality safety basis.

• Table 6.1.3-1 revised to list HCB CSIs

• §6.2.5 updated to specify ANSI N14.1 effective at the time of manufacturing

• §6.2.6 added to provide HCB fissile content description

• §6.3.1.3 added to provide HCB model configuration description

• §6.3.2.10 and 6.3.2.11, as well as Table 6.3.2-3 and 6.3.2-4 added to provide material description for the HCB and contents

• Table 6.3.3-1 revised to list HCB neutron history specification

• §6.3.4.4 editorial change for clarity

• §6.3.4.6 added to describe HCB analyses and methods

• §6.4.6 - HCB Single Package Analysis

• Table 6.5-1 updated to list NCT Array Size for HCB Analysis

• §6.5.6 - HCB NCT Array Analysis

• Table 6.6-1 updated to list HAC Array Sizes for HCB Analysis

• §6.6.6 - HCB HAC Array Analysis

• §6.8 updated to include new HCB USL equation and added supplemental benchmarks (HCT-011 and LCT-058) and corrected a transpositional error in Table 6.8.1-2 where ck values listed for experiment series LST-002 and LST-003 were incorrectly ordered. The transpositional error affected the cases included in the USL generation and the corrections made resulted in very small changes in USLs for the given contents. A summary of all updated USLs due to these corrections is provided in the following table (note that not all USLs were affected):

Content Enrichment OLD USL NEW USL 100 0.9399 0.9400 Standard 5 0.9423 0.9420 Hydrogen 100 0.9399 0.9400 Limited 5 0.9417 0.9420 5-inch Pipe 100 0.9399 0.9394 1S 100 0.9394 0.9395 Air 100 0.9399 0.9400 Transport 5 0.9417 0.9420 ii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Record of Revisions - Revision 13 (December 2021)

• §6.9.1 reference [1] date updated to Latest Revision and new references added in [5] and [7].

Other references renumbered by order first listed in the document accordingly.

Chapter 7

• §7.1.1 step j clarified to inspect threads on each pipe

• §7.1.1 added step k for the use of the HCB

• §7.1.2 added steps e for the use of the HCB

• §7.1.2 clarified in note k that part IG is always required when using the HCB Chapter 8

• §8.1.5 added CPVC material requirement

• §8.2.3.1 added step g for HCB inspection requirement prior to each use iii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 CONTENTS 1 GENERAL INFORMATION ................................................................................ 1-1 2 STRUCTURAL EVALUATION ............................................................................ 2-1 3 THERMAL EVALUATION ................................................................................... 3-1 4 CONTAINMENT ................................................................................................. 4-1 5 SHIELDING EVALUATION................................................................................. 5-1 6 CRITICALITY EVALUATION .............................................................................. 6-1 7 PACKAGE OPERATIONS .................................................................................. 7-1 8 ACCEPTANCE TESTS AND MAINTENANCE PROGRAM ............................... 8-1 iv

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 CONTENTS 1 GENERAL INFORMATION ................................................................................................................................ 1 1.1 Introduction ......................................................................................................................................... 1 1.2 Package Description.......................................................................................................................... 4 1.2.1 Packaging ......................................................................................................................................................... 4 1.2.2 Contents ........................................................................................................................................................... 6 1.2.3 Special Requirements for Plutonium................................................................................................... 7 1.2.4 Operational Features .................................................................................................................................. 7 1.3 References ............................................................................................................................................ 9 1.4 Appendices ......................................................................................................................................... 10 1.4.1 Versa-Pac Shipping Package Licensing Drawings........................................................................ 11 1.4.2 General Notes............................................................................................................................................... 16 1.4.3 UF-1 Polyurethane Closed Cell Foam Specification .................................................................... 18 1.4.4 Ceramic Fiber Insulation Specification ............................................................................................. 19 1.4.5 Structural Fiberglass Component Specification ........................................................................... 20 1.4.6 Versa Pac VP-55 5-inch Pipe ................................................................................................................. 21 1.4.7 VP-55 5-inch Pipe Licensing Drawings............................................................................................. 22 1.4.8 Versa-Pac VP-55 High-Capacity Basket (HCB) .............................................................................. 24 1.4.9 High-Capacity Basket (HCB) Licensing Drawings ........................................................................ 25 TABLES TABLE 1-1: U-235 LOADING TABLE FOR VP-55 AND VP-110 STANDARD CONFIGURATION ............................................................. 1 TABLE 1-2: HYDROGEN-LIMITED U-235 LOADING TABLE FOR MODEL NOS. VP-55 AND VP-110 .................................................. 1 TABLE 1-3: U-235 LOADING TABLE FOR THE VP-55 WITH 5-INCH PIPE ............................................................................................... 2 TABLE 1-4: HYDROGEN LIMITED LOADING TABLE FOR THE VP-55 WITH 5-INCH PIPE........................................................................ 2 TABLE 1-5: 1S/2S CYLINDER LIMITS FOR THE VP-55 (UP TO 20-WT.% U-235)................................................................................ 3 TABLE 1-6: 1S/2S CYLINDER LIMITS FOR THE VP-55 WITH 5-INCH PIPE (UP TO 100-WT.% U-235) ........................................... 3 TABLE 1-7: POLYURETHANE CLOSED CELL FOAM COMPONENT REQUIREMENTS ................................................................................ 18 TABLE 1-8: CERAMIC FIBER INSULATION REQUIREMENTS....................................................................................................................... 19 FIGURES FIGURE 1-1: VERSA-PAC COMPONENT ILLUSTRATION ................................................................................................................................. 8 1-i

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1 GENERAL INFORMATION 1.1 Introduction The Versa-Pac is a drum type package that features a patented [1] design concept in combination with the familiar drum exterior packaging to provide enhanced structural protection to payloads during the Normal Conditions of Transport (NCT) and Hypothetical Accident Conditions (HAC) [2]. Principal design of the Versa-Pac packaging maintains the use of an inner container positioned inside a 55-gallon (VP-55) or 110-gallon drum (VP-110). The Versa-Pac is used directly or in conjunction with pails, pipe containers, poly bottles, and a variety of smaller containers, inserts and vessels. The payload containment area of the 55-gallon version (VP-55) has an inside diameter of 15 inches (38.1 cm) and is 25-7/8 inches (65.72 cm) in length. The 110-gallon version (VP-110) has an inside diameter of 21 inches (53.34 cm) and is 29-3/4 inches (75.57 cm) in length. The package has two distinct areas of insulation for thermal and impact protection.

The Versa-Pac standard configuration shipping packages, model numbers VP-55 and VP-110, have been designed to transport Type A fissile materials limited to U-235 masses based on the loading limits in Table 1-1. The Criticality Safety Index (CSI) for the VP-55 and VP-110 in its standard configuration is 1.0.

Table 1-1: U-235 Loading Table for VP-55 and VP-110 Standard Configuration U-235 Mass Limit Enrichment U-(g) 235 (wt.%)

Ground/Vessel Air

£ 100 360 350

£ 20 445 410

£ 10 505 470

£5 610 580

£ 1.25 1650 --

For contents limited to 1 lb. (454 g) of hydrogenous packaging materials, the quantity of fissile material per package is limited to the U-235 masses listed in Table 1-2. Uranium compounds containing any hydrogen (e.g., hydrates or hydrides) are not permissible for contents limited by Table 1-2.

Table 1-2: Hydrogen-Limited U-235 Loading Table for Model Nos. VP-55 and VP-110 U-235 Mass Limit Enrichment U-235 (g)

(wt.%)

CSI=0.7 CSI=1.0 100 515 -

£ 20 605 635 10 685 -

5 800 -

1-1

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 An additional Versa-Pac packaging configuration features a 5-inch steel inner container to facilitate the transport of greater quantities of U-235 and is fully described in Appendix 1.4.6. The VP-55 with 5-inch pipe configuration is designed to transport Type A fissile materials limited to U-235 masses based on the loading limits in Table 1-3, with all fissile contents loaded into a single 5-inch pipe. The CSI for the VP-55 with 5-inch pipe configuration is 0.7 for material up to 10-wt.%,

and 1.0 for material greater than 10-wt.% up to 100-wt.%.

Table 1-3: U-235 Loading Table for the VP-55 with 5-inch Pipe U-235 Mass Limit Enrichment U-(g) 235 (wt.%)

Ground/Vessel Air

£ 100 695 395

£ 20 1215 495

£ 10 Full Pipe 590

£5 Full Pipe 790 When utilizing the 5-inch pipe component with contents limited to 1.25 lb. (567 g) of hydrogenous packaging materials per pipe, the quantity of fissile material per package is limited only by the volume of the 5-inch pipe(s). The number of pipes per container and CSI of each content is listed in Table 1-4, below. Uranium compounds containing any hydrogen (e.g., hydrates or hydrides) are not permissible for contents limited by Table 1-4. To ship two 5-inch pipes per package with material up to 20-wt%, the pipes must be loaded into the High-Capacity Basket (HCB). Uranium metal is not a permissible content when utilizing the HCB.

Table 1-4: Hydrogen Limited Loading Table for the VP-55 with 5-inch Pipe Enrichment U-235 Number of CSI a (wt.%) Pipes 20% 1 CSI = 1.0 For all Uranium compounds 2 CSI = 0.7 for U3O8, UO3, or UF4 20%

(in the HCB) CSI = 1.4 for all other Uranium compounds CSI = 1.0 for Uranium Oxides 10% 2 CSI = 1.4 for all other Uranium compounds a

Notes: Uranium compounds includes Uranium metal, except in the HCB. Uranium metal is not a permissible content in the HCB configuration.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 An added content for the VP-55 is ANSI N14.1 [3] compliant 1S and 2S cylinders filled with uranium hexafluoride (UF6). The 1S or 2S cylinders must be compliant with the version of ANSI N14.1 effective at the time of the cylinder fabrication. The VP-55 can ship 1S or 2S UF6 cylinders based on the 20-wt.% U-235 limits provided in Table 1-5. Each shipment of this content type may only contain either 1S cylinders or 2S cylinders. Quantities of cylinders greater than the limits stated in Table 1-5, or combinations of 1S and 2S cylinders in a single package (e.g., one 1S cylinder and two 2S cylinders), are permissible if the total U-235 quantity meets the fissile limits, for the maximum enrichment, established in Table 1-1. The air transport U-235 mass limits in Table 1-5 is the lesser of the 1S/2S cylinder limits and the air transport limits determined in Section 6.7. For 1S/2S cylinder contents limited by Table 1-5, the CSI is 1.0.

Table 1-5: 1S/2S Cylinder Limits for the VP-55 (up to 20-wt.% U-235)

Maximum Mass UF6 per U-235 Mass Limit Air U-235 Mass Enrichment U-235 Content Cylinders per VP-55 per VP-55 Limit (wt.%)

VP-55 (lb/g) (g) (g) 1S Cylinder 7 7.0 / 3,175 £ 20 429.8 429.8 2S Cylinder 2 9.8 / 4,445 £ 20 600.8 495 Also, ANSI N14.1 compliant 1S and 2S cylinders filled with uranium hexafluoride (UF6) with U-235 enrichments up to 100-wt.% can be shipped in the VP-55 with 5-inch pipe configuration based on the limits provided in Table 1-6. For this configuration, each 1S or 2S cylinder is loaded into a 5-inch pipe and the 5-inch pipes are loaded into the VP-55 prior to shipment. Each shipment of this content type may only contain either 1S cylinders or 2S cylinders. Quantities of cylinders greater than the limits stated in Table 1-6, or combinations of 1S and 2S cylinders in a single package (e.g., one 1S cylinder and two 2S cylinders), are permissible if the total U-235 quantity meets the fissile limit, for the maximum enrichment, established in Table 1-1. The air transport U-235 mass limits in Table 1-6 is the lesser of the 1S/2S cylinder limits and the air transport limits determined in Section 6.7. For 1S/2S cylinder contents limited by Table 1-6, the CSI is 1.0.

Table 1-6: 1S/2S Cylinder Limits for the VP-55 with 5-inch Pipe (up to 100-wt.% U-235)

Maximum Mass UF6 per U-235 Mass Air U-235 Mass Cylinders Enrichment U-235 Content VP-55 Limit per VP-55 Limit per VP-55 (wt.%)

(lb/g) (g) (g)

(in 5-inch Pipe(s))

1S Cylinder 1a 1.0 / 454 £ 100 306 306 2S Cylinder 1 4.9 / 2,223 £ 100 1497 395 a

Notes: Limited to one cylinder based on fit inside of the VP-55 cavity with the required 2-inch thick foam liner.

1-3

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.2 Package Description 1.2.1 Packaging Engineering Drawings are provided in Appendix 1.4.1. General notes pertaining to fabrication are provided in Appendix 1.4.2. An illustration of the packaging configuration is provided in Figure 1-1. Packaging markings are shown on the drawings in Appendix 1.4.1.

The exterior skin of the Versa-Pac consists of, at a minimum, a UN1A2/Y425/S for the VP-55.

The drums use a bolted closure ring, standard carbon steel lugs, 5/8 (1.59 cm) diameter, ASTM (American Society for Testing Materials) A429 bolts and nuts, and a closed-cell rubber lid gasket.

The overall outer dimensions of the 55-gallon drum are 23-3/16 (58.9 cm) OD x 34-3/4 (88.27 cm) in height to the top of the outer drum bolt ring. The drum cover is reinforced by a 10-gauge thick 22-3/8 (56.83 cm) OD x 18-3/8 (46.69 cm) ID plate, and four 1/2 (1.27 cm) bolts are provided to lend additional strength to the drum closure ring.

The VP-110 utilizes at a minimum a UN1A2/Y409/S. The drums use a bolted closure ring, standard carbon steel lugs, 5/8 (1.59 cm) diameter ASTM A429 bolts and nuts, and a closed-cell lid rubber gasket. The overall outer dimensions for the 110-gallon drum are 30-7/16 (77.31 cm)

OD x 42-3/4 (108.59 cm) in height to the top of the outer drum bolt ring. The drum cover is reinforced by a 10-gauge thick 29-3/4 (75.565 cm) OD x 27-1/4 (68.22 cm) ID plate and eight 1/2 (1.27 cm) bolts are provided to lend additional strength to the drum closure ring.

Both drums are further strengthened with vertical stiffeners fabricated from 1-1/4 (3.175 cm) carbon steel square tubing, two inner liners of rolled 16-gauge carbon steel insulated by ceramic fiber blanket (which encase the vertical tubing), and a 1/4 (0.64 cm) carbon steel reinforcing plate on the bottom.

The packages inner container is completely insulated with the appropriate layers of ceramic fiber blanket around the containment area with rigid polyurethane foam disk on the top and on the bottom to complete the insulation of the package. Specifications for the insulation are provided in Appendices 1.4.3 for the polyurethane foam and 1.4.4 for the ceramic fiber blanket. The primary function of both insulations is to provide thermal protection. Although the rigid polyurethane provides some impact protection, the frame of the packaging performs much of the required impact protection.

A 1/2 (1.27 cm) thick fiberglass ring is used as a thermal break at the payload cavity flange. The thermal break is sandwiched between the steel components, with twelve 1/2-inch (1.27 cm) bolts providing the connection between the structural members through the fiberglass. This break effectively limits the flow of heat to the payload cavity through the steel flange components. There are no moving parts to the thermal break, and its functionality is maintained if it separates from the steel components FB, top stiffening ring, from FK, connection ring (See Drawings in Appendix 1.4.1). A specification for the fiberglass material is provided in Appendix 1.4.5.

The containment boundary of the package is defined as the payload vessel with its associated welds, payload vessel high temperature heat resistant silicone coated fiberglass gasket, payload vessel blind flanges, and reinforcing ring.

The payload vessel is comprised of a 10-gauge carbon steel sheet for the body and bottom. The upper end of the vessel is fitted with a 1/4 (0.64 cm) inner carbon steel flange ring with a 1/2 (1.27 cm) thick carbon steel blind flange. The vessel has three circumferential welds (two at the flange, one at the base) and one longitudinal weld. A 1/8 (0.32 cm) high temperature heat resistant silicone coated fiberglass gasket is used between the steel flange ring and blind flange. The 1-4

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 payload vessel blind flange is secured with twelve 1/2 (1.27 cm) bolts. There are no penetrations, valves or venting devices used within the containment boundary. The Versa-Pac meets the General Requirements for all packages, as specified in 10 CFR 71.43 [3].

Gross Weights The gross weights of the two Versa-Pac models are 750 pounds (340.2 kg) for the VP-55 and 965 pounds (437.7 kg) for the VP-110, see Section 2.1.3.

Materials of Construction The materials of construction of the Versa-Pac are provided in the Licensing Drawings parts list presented in Appendix 1.4.1.

Outer and Inner Protrusions There is one outer protrusion on the Versa-Pac consisting of carbon steel fitting which contains a 1 (2.54 cm) plastic plug on the side of the package. The plug is designed to melt and allow venting of any gases that might develop in the event of a fire. The protrusion extends less than 1/2 (1.27 cm) from the sidewall of the outer drum and does not impede the stacking or handling of the shipping package. There are no inner protrusions on the Versa-Pac.

Lifting and Tie-Down Devices The Versa-Pac may be handled by normal industry standards for the safe movement of drums; such equipment might include specifically designed devices, forklifts, pallet jacks or other methods as determined by the User. However, the Versa-Pac does not utilize any specific device or attachment for lifting. Additionally, there are no specific provisions for tie down of the package.

Shielding Neutron and gamma shields are not required for the Versa-Pac payloads.

Pressure Relief Systems There are no pressure relief systems other than the four 1/4 (0.64 cm) holes, closed with vinyl push plugs on the inner liner between the insulation and containment and one in the top cavity area used to vent gases that might be produced in the event of a fire. No special heat transfer mechanisms are provided or required.

Containment Features There are three individual points of closure employed by the Versa-Pac. The payload 1/2 (1.27 cm) inch thick closure plate provides a fastening and seal using twelve 1/2 (1.27 cm) bolts and a 1/8 (0.32 cm) thick silicone coated fiberglass gasket. A second closure is provided at the outer drum lid. The drum lid is secured using 1/2 (1.27 cm) bolts and is sealed with a 3/8 (0.95 cm) thick silicone rubber flat gasket. A standard drum ring, its rubber gasket, and a 5/8 (1.59 cm) tensioning bolt provide the final closure. A 1/8 (0.32 cm) hole is drilled in the end of the tensioning bolt for use with a security seal.

The primary containment boundary of the Versa-Pac is defined as the inner containment body, containment end plate, inner flange ring, silicone coated fiberglass gasket, 1/2 (1.27 cm) blind flange, 1/2 (1.27 cm) bolts, washers and insert holders. Figure 1-1 further illustrates these components by text description enclosed within a text box.

Package Markings Package markings are shown in Appendix 1.4.1 and 1.4.2.

1-5

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.2.2 Contents All materials must be in solid form with no freestanding liquids; density is not limited. Material quantities may not exceed the fissile limits established in Section 1.1 in any non-pyrophoric form.

Materials that may be shipped in the Versa-Pac include uranium oxides (UyOx), uranium metal (U-metal), uranyl nitrate crystals (UNX), and other uranium compounds (e.g., Uranyl Fluorides and Uranyl Carbonates). The uranium compounds may also contain carbon or graphite (e.g., UC, U2C3 and UC2). UNX may be in the form of uranyl nitrate hexahydrate, trihydrate or dihydrate, and must be in solid form. The payload may be in homogeneous (powder or crystalline) or non-homogeneous form. The fissile contents may include neutron absorbers (e.g., boron, hafnium, erbium, or gadolinia). The contents are limited to Type A, normal form material per 10 CFR 71 [3].

Additionally, the Versa-Pac may be used to transport TRISO fuels and compacts composed of UCO kernels encased within layers of SiC to form TRISO particles. UCO kernels and TRISO particles are of unrestricted size, density, and uranium content per kernel/particle. UCO kernels and TRISO particles may be loose or mixed in a graphite matrix and pressed into various fuel forms (e.g. annular cylinders, planks, right circular cylinders, spheres, etc.).

The Versa-Pac is evaluated assuming optimum moderation using a bounding high-density polyethylene plastic (Density = 0.98 g/cc) and supports packaging applications containing both carbon (e.g., graphite and PTFE) and hydrogen-based materials (e.g., water paraffin, and polyethylene). Non-fissile chemical impurities do not increase the reactivity of the system; therefore, they may be present in any quantity. The payload may be enriched in U-235 to 100-wt.% while maintaining the limits in Section 1.1. Because the payload decay heat is essentially zero (approximately 11.4 W, Section 3.4.2), there are no radiolytic decay products.

When using the 5-inch pipe configuration, all fissile contents must be loaded into a single 5-inch pipe or two 5-inch pipes, based on the limits presented in Section 1.1, and sealed per the instructions in Section 7. The fissile quantity for this configuration shall meet the limits in Table 1-3 or 1-4. To ship two 5-inch pipes per package with enrichment no greater than 20-wt%, the 5-inch pipes must be loaded into the HCB.

Additional contents include uranium hexafluoride (UF6) in ANSI N14.1 compliant 1S and 2S cylinders or in sample tubes, when in quantities less than 0.1 kg. For any shipments of UF6 contents, a foam insert (9 PCF polyethylene) shall be used to provide thermal protection for the cylinder. The minimum foam insert thickness shall be 2 inches, circumferentially between the 1S/2S cylinders and the cavity wall of the Versa-Pac. Cribbing or dunnage may be used inside the foam insert to restrict movement of the contents during transport, providing a snug fit for the 1S/2S cylinders or 5-inch pipe. The fissile quantity of material in any shipment of 1S/2S cylinders must meet one of the following requirements:

1. The number of cylinders in a single package shall meet the limitations in Table 1-5, or Table 1-6 when each cylinder is packaged into a separate 5-inch pipe. For this case, either 1S or 2S cylinders may be loaded into a single package (i.e., no mixing of cylinder types).

2. The total fissile mass (in grams of U-235) from all cylinders shall meet the limits set in Table 1-1. For this case, any number or combination of 1S and 2S cylinders is acceptable, so long as the U-235 mass limit is not exceeded. The U-235 mass limit for this case is established based on the cylinder with the highest enrichment (e.g. for two cylinders with enrichments of 5-wt.% and 15-wt.%, respectively, the U-235 mass limit is based on the 20-wt.% limit).

1-6

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 The payload material may be pre-packaged in hydrogenous or non-hydrogenous containers within the payload vessel. Hydrogenous pre-packaging materials may include polyethylene, polypropylene, and PVC (polyvinyl chloride). PTFE (Polytetrafluoroethylene) or Teflon pre-packaging material is also allowed. Metallic pre-packaging materials such as aluminum, stainless and carbon steel are allowed.

For contents limited to 1 lb. (454 g) of hydrogenous packaging materials, the quantity of fissile material per package is limited to the U-235 masses listed in Table 1-2. For contents limited to 1.25 lb. (567 g) of hydrogenous packaging materials loaded into the 5-inch pipe(s), fissile limits are listed in Table 1-4. Uranium contents shipped under the Table 1-2 or Table 1-4 fissile limits may not include uranium compounds containing any hydrogen (e.g., hydrates or hydrides).

Package contents are typically shipped in an axial array to fill the payload cavity. A fireproof perlite-like packing material is often used as dunnage to fill the voids between the cans and inner vessel wall. The Versa-Pac design allows for the use of two neoprene pads: a 1/8 inch (0.32 cm) bottom pad and a 3/8 inch (0.96 cm) top pad. The pads serve the purpose of protecting the inner containment shell during repeated use. The use of these pads is optional for packages not intended for reuse.

No materials, excluding the minimum steel wall thickness of the package, are credited as neutron absorbers or moderators.

The maximum payload capacity for the VP-55 is 350 pounds (158.8 kg). The maximum payload capacity for the VP-110 is 260 pounds (117.9 kg).

1.2.3 Special Requirements for Plutonium The Versa-Pac is not approved for the transport of Plutonium above minimum detectable quantities.

1.2.4 Operational Features The Versa-Pac provides for two individual closures and seals, with a third closure provided by the drum ring, to secure the payload within the inner containment area. Connections and closures are accomplished using bolt and gasket seals.

There are no operationally complex features of the Versa-Pac. All operational features are readily apparent from an inspection of the drawings provided in Appendix 1.4.1, Packaging General Arrangement Drawings. Operation procedures and instructions for loading, unloading, and preparing an empty Versa-Pac for transport are provided in Chapter 7.0, Operating Procedures.

1-7

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 1-1: Versa-Pac Component Illustration (Containment boundary components, as indicated in Section 1.2.1.7, are described in text boxes) 1-8 BLIND NUT W/INSERT HOLDER

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.3 References IAEA package design regulations, SSR-6, 2012 Ed. [4], have been incorporated by reference into 49 CFR 171.7 [5]. The design requirements for Type A packages are typically the same between the IAEA and NRC 10 CFR 71 [3] regulations, therefore, the package design maintains compliance to both regulatory references. Note the in-text references are specific to NRC regulations.

[1] U.S. Patent and Trademark Office (USPTO), "Patent No. 7,628,287 B1, Reusable Container Having Spaced Protective Housings," 2009.

[2] Nuclear Regulatory Commission (NRC), Title 10, Part 71-Packaging and Transportation of Radioactive Material.

[3] American National Standards Institute, "Uranium Hexafluoride - Packagings for Transport,"

ANSI N14.1, Latest Revision.

[4] International Atomic Energy Agency (IAEA), Regulations for the Safe Transport of Radioactive Material, SSR-6, 2012 Edition.

[5] United States Department of Transportation (USDOT), Title 49, Code of Federal Regulations Part 173, Subpart I - Class 7 (Radioactive) Materials.

[6] The American Society for Nondestructive Testing, Inc., "Recommended Practice No. SNT-TC-1A Personnel Qualification and Certification in Nondestructive Testing," 2006.

[7] The Engineering Tool Box, "Fuels and Chemicals - Auto Ignition Temperatures," [Online].

Available: http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html.

1-9

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.4 Appendices 1.4.1 Versa-Pac Shipping Package Drawings Drawing No. VP-55-LD Rev. 5, VP-110-LD Rev. 3 1.4.2 General Notes 1.4.3 UF-1 Polyurethane Closed Cell Foam Specification 1.4.4 CFI-1 Ceramic Fiber Insulation Specification 1.4.5 Structural Fiberglass Component Specification 1.4.6 VP-55 5-inch Pipe Description 1.4.7 VP-55 5-inch Pipe Licensing Drawing 1.4.8 Versa-Pac VP-55 High-Capacity Basket (HCB) Description 1.4.9 High-Capacity Basket (HCB) Licensing Drawings 1-10

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.4.1 Versa-Pac Shipping Package Licensing Drawings (4 Sheets) 1-11

a,c 8 7 6 5 4 3 2 1 D D C C B B A A 8 7 6 5 4 3 2 1

a,c 8 7 6 5 4 3 2 1 D D C C B B A A 8 7 6 5 4 3 2 1

a,c 8 7 6 5 4 3 2 1 D D C C B B A A 8 7 6 5 4 3 2 1

a,c 8 7 6 5 4 3 2 1 D D C C B B A A 8 7 6 5 4 3 2 1

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, March 2021 1.4.2 General Notes

1. Paint all carbon steel surfaces with (2 mils.) of industrial primer. The drum exterior surface is to be painted with (2 mils.) of topcoat, touchup with compatible spray paint as necessary.

2. Placard as required.

3. Welding procedures and personnel shall be qualified in accordance with AWS D1.1, Structural Welding Code - Steel, and AWS D1.3, Structural Welding Code - Sheet Steel, as applicable.

4. NDT Personnel shall be qualified in accordance with SNT-TC-1A [6]. Visual personnel may be certified in addition or in lieu of SNT-TC-1A as an AWS (American Welding Society) CWI (Certified Welding Inspector) or CAWI (Certified Associate Welding Inspector).

5. Nameplates shall be attached after painting and paint retouched. Spot welding and riveting are both acceptable methods of attachment.

6. General shop tolerances of +/-1/4 (0.64 cm) apply unless noted. Material tolerances are as required under the appropriate specification.

7. Equivalent components must be approved by engineering and submitted to the NRC for approval.

8. This package shall be manufactured under a Quality Assurance Program that meets the program requirements as outlined in 10 CFR 71 [3]. Quality Assurance shall perform visual inspections on all final welds and magnetic particle (MT) or liquid penetrant (PT) inspections on all final welds indicated as such in the VP-55 and VP-110 Licensing Drawings, per the requirements of AWS D1.1. Although the Licensing Drawings only specify MT, either MT or PT inspections are acceptable for all relevant welds.

9. The nameplate shall be a minimum of 6 (15.24 cm) x 6 (15.24 cm) x 22-gauge stainless steel, ASTM 300 Series. The letters shall be at least 1/2 (1.27 cm) high as follows and include at a minimum the following information:

Mfg. by:

S/N:

Versa-Pac VP-55 or VP-110 Type AF-96 Tare Wt: ________ LB

________ KG Max. Gross Wt: ________ LB

________ KG 1-16

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021

10. Gaskets and Plugs shall be installed using the appropriate material as described on the licensing drawing parts list.

11. Ceramic fiber paper/blanket/boards and polyurethane foam products shall be in accordance with the specifications listed in Appendices 1.4.3 through 1.4.5.

12. Certifications, test reports and QA records shall be stored and maintained as required by the Orano TLI Quality Assurance Program.

13. Stenciling shall be in contrasting color and be a minimum of 1 (2.54 cm) in height unless noted and shall include at a minimum the following information:

Design ID Number: USA/9342/AF-96 Type A (2 Letters)

Model Number: Versa-Pac VP-(55 or 110)

Owners Name: ----------------------------------------

Owners Address: City, State, and/or Country RQ, Radioactive Material, Type A Package, Fissile Non-Special Form

14. For the minimum UN specification in Part DA, equivalency between X and Y packing groups is based off of the drop heights required for testing in 49CFR178.603(e). Packing group I (X) requires a test drop height of 1.8 meters and packing group II (Y) requires a test drop height of 1.2 meters. Based on the potential energy, the equivalent mass for the higher drop (X) is equal to (1.2/1.8)*425 = 283.3 kg for the VP-55 and (1.2/1.8)*409 =

272.7 kg for the VP-110. The minimum X specification for both of these is rounded up to 350 kg.

(Additional stenciling of the package is at the discretion of the customer. RQ may not be required since it is dependent on the payload contents.)

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.4.3 UF-1 Polyurethane Closed Cell Foam Specification This appendix provides the specification for all polyurethane closed cell foam products used in the Versa-Pac packaging. The basic physical property requirements for the polyurethane closed cell foam components of the Versa-Pac are listed in Table 1-7. The urethane foam resins, urethane foam components, and other raw processing materials should be stored at room temperature. The foam is a two-component rigid polyurethane system. The foam may be generated in place or with molds, however the process used shall incorporate proper controls to ensure that there are no abnormalities or voids in the foam blocks. All polyurethane foam components used in the Versa-Pac must have a hydrogen density less than that of water.

Table 1-7: Polyurethane Closed Cell Foam Component Requirements Parameter Requirement 1

Density 5 to 11 PCF (Test - ASTM D-1622)

Compressive Strength 80 to 300 PSI (Test - ASTM D-1621 or ASTM D-695)

Maximum Thermal Conductivity 0.274 BTU-in/hr-ft2-°F (Test - ASTM C-518)

Flame Retardancy Meet the minimum requirements of ASTM E84 or FAR 25.853 Chloride Content Leachable chloride < 200 ppma a

Notes: This value shall be determined through independent laboratory testing.

1-18

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.4.4 Ceramic Fiber Insulation Specification This appendix provides the specification for all ceramic fiber insulation products used in the Versa-Pac packaging. The ceramic fiber insulation components of the Versa-Pac shall be Morgan Thermal Ceramics Kaowool 500, or equivalent for paper products (12 to 14 PCF), and Morgan Thermal Ceramics Cerablanket (6 or 8 PCF), or equivalent for blanket products. Because the ceramic fiber paper and blanket products in the Versa-Pac are only necessary for thermal protection, equivalency is based on the composition, density, and thermal conductivity of the products.

Material -

For a paper or blanket product to be considered equivalent to the specified products, it must be composed of alumina and silica oxides.

Density -

Papers: 12 - 14 PCF Blankets: 6 - 8 PCF Thermal Conductivity -

Table 1-8: Ceramic Fiber Insulation Requirements Temperature Thermal Conductivity

(°F) (BTU-in/hr-ft2-°F) 500 0.47 1000 1.06 1500 1.90 1-19

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.4.5 Structural Fiberglass Component Specification This appendix provides the specification for all structural fiberglass insulation products used in the Versa-Pac packaging. The Structural Fiberglass components of the Versa-Pac shall be Strongwell Series 500/525 structural fiberglass, or equivalent. Because the structural fiberglass products in the Versa-Pac are only necessary for thermal protection, equivalency is based on the composition, density, and thermal conductivity of the products.

Material -

For a structural fiberglass product to be considered equivalent to the product specified, the material shall consist of a glass fiber reinforced polyester or vinyl ester resin matrix with glass reinforcements.

Density -

The density of any structural fiberglass component to be considered equivalent shall be in the following range: 0.062 - 0.070 lb/in3.

Thermal Conductivity -

The thermal conductivity of any structural fiberglass component to be considered equivalent shall be 4.0 BTU-in/hr-ft2-°F.

1-20

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.4.6 Versa Pac VP-55 5-inch Pipe 1.4.6.1 VP-55 with 5-inch Pipe Packaging Description The 5-inch pipe container fits inside the VP-55 payload vessel. The payload vessel is described in Section 1.2.1. Licensing Drawings are provided in Section 1.4.1.

The 5-inch pipe container is fabricated from Schedule-40 carbon steel. There is a carbon steel plate welded to the bottom. The top is closed with a 5-inch threaded cap made from malleable iron. The pipe container is typically held in place during routine transport by a basket or birdcage device that provides no structural support. It is considered dunnage. No credit is taken for the pipe maintaining a specific position within the payload cavity under non-routine conditions.

Operating instructions for the VP-55 5-inch Pipe are provided in Sections 7.1 and 7.2. When utilized in the VP-55, the 5-inch pipe is simply used for geometric confinement of the fissile material in the contents. Although all radioactive material is confined inside the pipe during all transport conditions, the containment boundary of the package is always the inner vessel of the Versa-Pac package. The 5-inch pipe, contents, and any additional dunnage/cribbing are accounted for as the total content weight in the determination of the maximum payload weight for the VP-55 package (see Section 2.1.3).

1.4.6.2 VP-55 with 5-inch Pipe Contents The 5-inch pipe container and any additional dunnage/cribbing are considered contents of the VP-55 package in this configuration. All radioactive contents are loaded directly into the 5-inch pipe when shipping in this configuration. The material requirements for the 5-inch pipe configuration are identical to the standard VP-55 requirements. The fissile material limits for the VP-55 with 5-inch pipe configurations are provided in Table 1-3, Table 1-4, and Table 1-6.

1-21

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.4.7 VP-55 5-inch Pipe Licensing Drawings (1 Sheet) 1-22

a,c 4 3 2 1 D D C C B B A A 4 3 2 1

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.4.8 Versa-Pac VP-55 High-Capacity Basket (HCB) 1.4.8.1 VP-55 with High-Capacity Basket Description The High-Capacity Basket (HCB) supports two (2) 5-inch pipe containers and fits inside the Versa-Pac payload cavity, which is described in Section 1.2.1. VP-55 and HCB licensing drawings are provided in Sections 1.4.1 and 1.4.9, respectively.

The HCB consists of two isolating silos constructed of 6-inch (15.2 cm) Schedule 80 CPVC pipe with 0.435 in. (1.105 cm) wall thickness and 17.0 in. (43.2 cm) in height. Centered between the two silos is a CPVC isolating plate, 0.5 in. (1.27 cm) thick, 12.0 in. (30.5 cm) wide, 17.0 in.

(43.2 cm) in height. These isolating components are assembled in an aluminum basket structure.

The basket features four 14.4 in. (36.6 cm) diameter, 0.5 in. (1.27 cm) thick aluminum plates spaced along the axis of the HCB body. The top plate is solid with two cutouts for the two pipe containers. The two middle aluminum plates feature cutouts for the isolating silos and plate with the silos symmetric about the centerline of the plate. The bottom plate is solid and provides vertical support for the pipe containers. The aluminum support plates are interlocked together using four (4) vertical basket stiffener arms. The stiffener arms are fastened together laterally using two threaded rods at the top and bottom of the basket assembly. Additional support is provided by four axial connecting rods adjacent to the stiffener arms and secured with socket head cap screws on both ends of the assembly. Void space in the basket is filled with insulating material, which provides thermal protection for the isolating components. Thin gauge sheet metal wraps the basket to protect the insulating material during handling.

Operating instructions for the HCB with two (2) 5-inch pipes are provided in Sections 7.1 and 7.2.

The HCB features silos and isolating plates that reduce neutron communication between the two adjacent pipe containers, allowing for increased fissile contents. Although all radioactive material is confined inside the two (2) 5-inch pipes in the HCB during all transport conditions, the containment boundary of the package is always the inner vessel of the Versa-Pac package. The HCB and its two (2) 5-inch pipe containers, contents, and any additional dunnage/cribbing are accounted for as the total content weight in the determination of the maximum payload weight for the VP-55 package (see Section 2.1.3). The sourced CPVC material for the HCB shall meet the requirements for [

]a,c Table 1-9: CPVC Critical Characteristics a,c 1.4.8.2 VP-55 with High-Capacity Basket Contents The HCB, its two (2) 5-inch pipe containers, and any additional dunnage/cribbing are considered contents of the VP-55 package in this configuration. All radioactive contents are loaded directly into two (2) 5-inch pipes in the HCB configuration. The material requirements for the HCB configuration are identical to the standard VP-55 requirements. The fissile material limits for the VP-55 with the HCB configuration are provided in Table 1-4.

1-24

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 1.4.9 High-Capacity Basket (HCB) Licensing Drawings (1 Sheet) 1-25

a,c 8 7 6 5 4 3 2 1 D D C C B B A A 8 7 6 5 4 3 2 1

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 CONTENTS 2 STRUCTURAL EVALUATION .................................................................................................................. 2-1 2.1 Description of Structural Design............................................................................................... 2-1 2.1.1 Discussion ............................................................................................................................................................. 2-1 2.1.2 Design Criteria .................................................................................................................................................... 2-2 2.1.3 Weights and Centers of Gravity................................................................................................................... 2-6 2.1.4 Identification of Codes and Standards for Package Design ............................................................. 2-6 2.2 Materials ........................................................................................................................................... 2-7 2.2.1 Mechanical Properties of Materials ........................................................................................................... 2-7 2.2.2 Chemical, Galvanic Reactions and Other Reactions............................................................................ 2-7 2.2.3 Effects of Radiation on Materials ................................................................................................................ 2-7 2.3 Fabrication and Examination ..................................................................................................... 2-9 2.3.1 Fabrication ........................................................................................................................................................... 2-9 2.3.2 Examination ......................................................................................................................................................... 2-9 2.4 General Requirements for All Packages ................................................................................. 2-9 2.4.1 Minimum Package Size ................................................................................................................................... 2-9 2.4.2 Tamper-Indicating Feature ........................................................................................................................... 2-9 2.4.3 Positive Closure................................................................................................................................................2-10 2.5 Lifting and Tie-down Devices ................................................................................................... 2-10 2.5.1 Lifting Devices ..................................................................................................................................................2-10 2.5.2 Tie-down Devices ............................................................................................................................................2-10 2.6 Normal Conditions of Transport (NCT) ................................................................................ 2-10 2.6.1 Heat .......................................................................................................................................................................2-11 2.6.2 Cold ........................................................................................................................................................................2-12 2.6.3 Reduced External Pressure ......................................................................................................................... 2-12 2.6.4 Increased External Pressure....................................................................................................................... 2-13 2.6.5 Vibration ............................................................................................................................................................. 2-13 2.6.6 Water Spray ....................................................................................................................................................... 2-13 2.6.7 Free Drop ............................................................................................................................................................ 2-13 2.6.8 Corner Drop ....................................................................................................................................................... 2-13 2.6.9 Compression ...................................................................................................................................................... 2-14 2.6.10 Penetration......................................................................................................................................................... 2-15 2.7 Hypothetical Accident Conditions (HAC) ............................................................................. 2-16 2.7.1 Free Drop ............................................................................................................................................................ 2-16 2.7.2 Crush .....................................................................................................................................................................2-22 2.7.3 Puncture .............................................................................................................................................................. 2-23 2.7.4 Thermal ............................................................................................................................................................... 2-24 2.7.5 Immersion - Fissile Material ...................................................................................................................... 2-25 2.7.6 Immersion - All Packages ............................................................................................................................ 2-25 2.7.7 Deep Water Immersion Test ...................................................................................................................... 2-25 2.7.8 Summary of Damage ......................................................................................................................................2-25 2.8 Accident Conditions for Air Transport of Plutonium ....................................................... 2-30 2.9 Accident Conditions for Fissile Material Packages for Air Transport ........................ 2-30 2.10 Special Form .................................................................................................................................. 2-30 2.11 Fuel Rods ......................................................................................................................................... 2-30 2-i

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12 Appendices ..................................................................................................................................... 2-30 2.12.1 References .......................................................................................................................................................... 2-31 2.12.2 VP-55 LS-DYNA analysis .............................................................................................................................. 2-33 2.12.3 High-Capacity Basket Stress Analysis.....................................................................................................2-71 2-ii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 FIGURES FIGURE 2-1. FREE DROP ORIENTATIONS EVALUATED FOR NCT AND HAC ..................................................................................... 2-35 FIGURE 2-2. THREE-DIMENSIONAL FINITE ELEMENT MODEL OF THE VP-55 ................................................................................ 2-36 FIGURE 2-3. EXPLODED VIEW OF VERSA-PAC 55 FINITE ELEMENT MODEL ................................................................................... 2-39 FIGURE 2-4. CARBON STEEL A36 STRAIN-HARDENING STRESS-STRAIN CURVE ............................................................................ 2-41 FIGURE 2-5. 5 PCF POLYURETHANE FOAM STRESS-STRAIN CURVES ............................................................................................... 2-42 FIGURE 2-6. NCT BOTTOM-END 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESDEFORMATION AT T = 0.011 S ....................................................................................................................................................................... 2-47 FIGURE 2-7. NCT BOTTOM-END 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESINNER CONTAINER CONTAINMENT END PLATE DEFLECTION (AT CENTER) ............................................................................................ 2-47 FIGURE 2-8. NCT BOTTOM-END 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESCONTENTS RIGID-BODY Z-ACCELERATION ............................................................................................................................................................. 2-48 FIGURE 2-9. NCT BOTTOM-END 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESENERGY TIME-HISTORIES .......................................................................................................................................................................... 2-48 FIGURE 2-10. NCT TOP-END 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESDEFORMATION AT T = 0.0136 S .................................................................................................................................................................... 2-50 FIGURE 2-11. NCT TOP-END 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESINNER CONTAINER BLIND FLANGE DEFLECTION (AT CENTER) .............................................................................................................................. 2-50 FIGURE 2-12. NCT TOP-END 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESCONTENTS RIGID-BODY Z-ACCELERATION.................................................................................................................................................................. 2-51 FIGURE 2-13. NCT TOP-END 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESENERGY TIME-HISTORIES ........... 2-51 FIGURE 2-14. NCT SIDE 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESDEFORMATION AT T = 0.016 S ........... 2-53 FIGURE 2-15. NCT SIDE 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIES CONTAINMENT BODY DEFLECTION (AT BOTTOM) ............................................................................................................................................ 2-53 FIGURE 2-16. NCT SIDE 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESCONTENTS RIGID-BODY Z-ACCELERATION.................................................................................................................................................................. 2-54 FIGURE 2-17. NCT SIDE 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESENERGY TIME-HISTORIES .................... 2-54 FIGURE 2-18. NCT TOP-CORNER 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESDEFORMATION AT T = 0.018 S ....................................................................................................................................................................... 2-56 FIGURE 2-19. NCT TOP-CORNER 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIES CONTAINMENT BODY DEFLECTION (AT BOTTOM) ............................................................................................................................................ 2-56 FIGURE 2-20. NCT TOP CORNER 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESCONTENTS RIGID-BODY Z-ACCELERATION ............................................................................................................................................................. 2-57 FIGURE 2-21. NCT TOP-CORNER 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESENERGY TIME-HISTORIES .......................................................................................................................................................................... 2-57 FIGURE 2-22. HAC BOTTOM-END 30-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESDEFORMATION AT T = 0.0062 S .................................................................................................................................................................... 2-60 FIGURE 2-23. HAC BOTTOM-END 30-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESINNER CONTAINER CONTAINMENT END PLATE DEFLECTION (AT CENTER) ............................................................................................ 2-60 FIGURE 2-24. HAC BOTTOM-END 30-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESCONTENTS RIGID-BODY Z-ACCELERATION .................................................................................................................................................. 2-61 FIGURE 2-25. HAC BOTTOM-END 30-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESENERGY TIME-HISTORIES .......................................................................................................................................................................... 2-61 FIGURE 2-26. HAC TOP-END 30-FT FREE DROP WITH HOT/SOFT FOAM PROPERTIESDEFORMATION AT T = 0.014 S ....................................................................................................................................................................... 2-63 FIGURE 2-27. HAC TOP-END 30-FT FREE DROP WITH HOT/SOFT FOAM PROPERTIESINNER CONTAINER CONTAINMENT END PLATE DEFLECTION (AT CENTER) ............................................................................................ 2-63 FIGURE 2-28. HAC TOP-END 30-FT FREE DROP WITH HOT/SOFT FOAM PROPERTIESCONTENTS RIGID-BODY Z-ACCELERATION.................................................................................................................................................................. 2-64 FIGURE 2-29. HAC TOP-END 30-FT FREE DROP WITH HOT/SOFT FOAM PROPERTIESENERGY TIME-HISTORIES ............ 2-64 FIGURE 2-30. NCT SIDE 30-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESDEFORMATION AT T = 0.0094 S .................................................................................................................................................................... 2-66 2-iii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 FIGURE 2-31. HAC SIDE30-FT FREE DROP WITH COLD/HARD FOAM PROPERTIES CONTAINMENT BODY DEFLECTION (AT BOTTOM) ............................................................................................................................................ 2-66 FIGURE 2-32. HAC SIDE 4-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESCONTENTS RIGID-BODY Z-ACCELERATION.................................................................................................................................................................. 2-67 FIGURE 2-33. HAC SIDE 30-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESENERGY TIME-HISTORIES ................. 2-67 FIGURE 2-34. HAC TOP-CORNER30-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESDEFORMATION AT T = 0.018 S ....................................................................................................................................................................... 2-69 FIGURE 2-35. HAC TOP-CORNER 30-FT FREE DROP WITH COLD/HARD FOAM PROPERTIES CONTAINMENT BODY DEFLECTION (AT BOTTOM) ............................................................................................................................................ 2-69 FIGURE 2-36. HAC TOP CORNER 30-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESCONTENTS RIGID-BODY Z-ACCELERATION .................................................................................................................................................. 2-70 FIGURE 2-37. HAC TOP-CORNER 30-FT FREE DROP WITH COLD/HARD FOAM PROPERTIESENERGY TIME-HISTORIES .......................................................................................................................................................................... 2-70 FIGURE 2-38. HCB SOLID MODEL ........................................................................................................................................................... 2-71 FIGURE 2-39. HCB FINITE ELEMENT MODEL ....................................................................................................................................... 2-75 FIGURE 2-40. LINEARIZED STRESS LOCATION ....................................................................................................................................... 2-79 FIGURE 2-41. HIGH-CAPACITY BASKET (HCB) FASTENERS ................................................................................................................ 2-81 2-iv

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 TABLES TABLE 2-1. EVALUATION RESULTS ..............................................................................................................................................................2-3 TABLE 2-2. VERSA-PAC SHIPPING PACKAGE GROSS WEIGHTS ...............................................................................................................2-6 TABLE 2-3. MECHANICAL PROPERTIES OF MATERIALS............................................................................................................................2-8 TABLE 2-4. NCT AND HAC TEST MATRIX .............................................................................................................................................. 2-11 TABLE 2-5.

SUMMARY

OF NCT AND HAC TEST RESULTS .................................................................................................................... 2-26 TABLE 2-6. VERSA-PAC TEST PACKAGE DIMENSIONAL CHANGES ...................................................................................................... 2-29 TABLE 2-7.

SUMMARY

OF CONDITIONS ANALYZED ................................................................................................................................ 2-33 TABLE 2-8. NCT 4-FT FREE DROP VP-55 PACKAGE CONTENTS PEAK ACCELERATION ............................................................... 2-33 TABLE 2-9. HAC 30-FT FREE DROP VP-55 PACKAGE CONTENTS PEAK ACCELERATION ............................................................ 2-33 TABLE 2-10. VP-55 FINITE ELEMENT MODEL PARTS ........................................................................................................................ 2-37 TABLE 2-11. MATERIAL IDS AND MATERIAL MODELS INCORPORATED IN THE LS-DYNA ANALYSIS ........................................ 2-40 TABLE 2-12. CARBON STEEL A36 MATERIAL PROPERTIES ................................................................................................................ 2-41 TABLE 2-13. E-GLASS FIBRE MATERIAL PROPERTIES ......................................................................................................................... 2-41 TABLE 2-14. 5 PCF POLYURETHANE FOAM STRESS-STRAIN DATA .................................................................................................. 2-42 TABLE 2-15. SILICONE RUBBER MATERIAL PROPERTIES (MIN/MAX VALUES) ............................................................................. 2-43 TABLE 2-16. VELOCITY USED IN THE LS-DYNA ANALYSES................................................................................................................ 2-44 TABLE 2-17. BOLT SIZES, SPECIFICATION, AND PRELOAD TORQUE .................................................................................................. 2-44 TABLE 2-18. NCT FREE DROP RESULTS

SUMMARY

............................................................................................................................. 2-45 TABLE 2-19. HAC FREE DROP RESULTS

SUMMARY

.............................................................................................................................. 2-58 TABLE 2-20. NCT SIDE DROP STRESS

SUMMARY

.................................................................................................................................. 2-72 TABLE 2-21. NCT BOTTOM END DROP STRESS

SUMMARY

................................................................................................................. 2-73 TABLE 2-22. HAC SIDE DROP STRESS

SUMMARY

................................................................................................................................. 2-73 TABLE 2-23. HAC BOTTOM END DROP STRESS

SUMMARY

................................................................................................................. 2-73 TABLE 2-24. MECHANICAL PROPERTIES OF SA-240, 304 STAINLESS STEEL ................................................................................ 2-76 TABLE 2-25. STRUCTURAL PROPERTIES OF ASTM B209 TYPE 6061-T6 ALUMINUM ALLOY ................................................... 2-76 TABLE 2-26. STRUCTURAL PROPERTIES OF CPVC ............................................................................................................................... 2-76 TABLE 2-27. ACCELERATION LOADS ....................................................................................................................................................... 2-77 TABLE 2-28. ALLOWABLE STRESS DESIGN CRITERIA FOR PLATES AND SHELLS ............................................................................. 2-78 TABLE 2-29. ALLOWABLE STRESS CRITERIA FOR BOLTED CONNECTIONS ....................................................................................... 2-78 TABLE 2-30. THREADED CONNECTION FORCE

SUMMARY

.................................................................................................................... 2-82 TABLE 2-31. THREADED ROD AND HEX NUT CONNECTION FORCE

SUMMARY

................................................................................ 2-82 TABLE 2-32. HEX SOCKET HEAD CAP SCREW - NCT STRESS

SUMMARY

.......................................................................................... 2-82 TABLE 2-33. THREADED ROD - NCT STRESS

SUMMARY

..................................................................................................................... 2-83 TABLE 2-34. HEX SOCKET HEAD CAP SCREW - HAC STRESS

SUMMARY

.......................................................................................... 2-83 TABLE 2-35. THREADED ROD - HAC STRESS

SUMMARY

..................................................................................................................... 2-83 2-v

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2 STRUCTURAL EVALUATION 2.1 Description of Structural Design 2.1.1 Discussion The Versa-Pac is a packaging designed for the shipment of radioactive materials containing less than or equal to the U-235 limits in Table 1-1 and Table 1-2, including uranium oxides (UyOx),

uranium metal (U-metal), uranyl nitrate crystals (UNX), and other uranium compounds (e.g.,

Uranyl Fluorides and Uranyl Carbonates). Tables 1-3 and 1-4 define the content requirements and restrictions for using the 5-inch pipe container. The ANSI N14.1 1S/2S cylinder [1] contents of the package are limited to the quantities specified in Table 1-5 and 1-6. The material may be pre-packaged in plastic, metal, or Teflon containers.

The 55-gallon version of the Versa-Pac, the VP-55, consists of a 15 (38.1 cm) inner diameter by 25-7/8 (65.7 cm) inner height (IH) containment area centered within an insulated 55-gallon (200 liter) drum. Drawings of the VP-55 are provided in Appendix 1.4.1. The Versa-Pac design utilizes standard shop dimensions, tolerances, and structural materials as outlined in the drawings in Appendix 1.4.1 and the General Note Sheet found in Appendix 1.4.2. An illustration of the packaging is provided in Figure 1-1.

The overall nominal dimensions of the VP-55 are 23-1/16 (65.7 cm) Outside Diameter (OD) x 34-3/4 (88.3 cm) in height to the top of the outer drum bolt ring. The containment area is protected with a gasketed inner containment lid that is closed with twelve 1/2 (13 mm) bolts. A polyurethane insulation plug is encapsulated in 16-gauge (1.5 mm) carbon steel welded onto the drum lid (see Appendix 1.4.3). The gasketed drum lid is closed with four 1/2 (13 mm) bolts and a standard drum ring. A gasket at the drum lids stiffening ring provides an additional barrier against water in-leakage.

The 55-gallon (200 liter) drum is strengthened with four longitudinal stiffeners fabricated from 1-1/4 (3.2 cm) carbon steel square tubing equally spaced around the circumference of the drum.

A 16-gauge (1.5 mm) outer liner and a 16-gauge (1.5 mm) inner liner provide additional insulated radial stiffness to the drum. The volume between the inner liner and the 10-gauge (3.4 mm) containment body is filled with ceramic fiber insulation (see Appendix 1.4.4).

The VP-55 5-inch (12.7 cm) pipe configuration results in at least double the contents of the VP-55, dependent on uranium-235 enrichment. This configuration includes one or two 5-inch (12.7 cm) pipe container(s) located in the payload cavity that provides criticality control of the fissile contents.

The 5-inch (12.7 cm) pipe container will be secured in the containment for routine transport with a birdcage or basket type constraining device that provides no structural support; it is considered dunnage. The 5-inch pipe container also offers no structural support to the packaging; it is considered part of the contents. No credit is taken for the pipe container maintaining a specific position in the payload cavity under either NCT or HAC for the purposes of criticality control.

The 5-inch (12.7 cm) pipe container is based on the DOT-specification 2R container, as outlined in 49 CFR 178 § 178.360 [2]. A drawing of the container is provided in Appendix 1.4.5. The container consists of a 5.56 (14.1 cm) OD pipe with a 0.26 (6.6 mm) wall thickness. The bottom cap of the container is a 0.25 (6.4 mm)-thick steel plate, and the top cap is an iron malleable cap with a height of 2.3 (5.8 cm) and a 16.8 (42.7 cm) maximum OD. The container has an outer height (OH) of 21.0 (53.3 cm) with all eight threads fully engaged and a corresponding inner height (IH) of 20.5 (52.2 cm).

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 A Hypothetical Accident Conditions (HAC) drop test series was performed on the 5-inch (12.7 cm) pipe container to verify its ability to maintain structural integrity and preserve the confinement of the fissile materials. Only the HAC drop test series was performed as the HAC series bounds Normal Conditions of Transport (NCT) drop tests and analyses. The HAC drop test series is documented in a separate report in Reference [3].

The VP-110 consists of a 21 (53.3 cm) Inside Diameter (ID) x 32-3/4 (83.2) Inside Height (IH) containment area centered within an insulated 110-gallon drum. Drawings of the VP-110 are provided in Appendix 1.4.1. The Versa-Pac design utilizes standard shop dimensions, tolerances and structural materials as outlined in the drawings in Appendix 1.4.1 and the General Note Sheet in Appendix 1.4.2. An illustration of the packaging is provided in Figure 1-1.

The overall nominal dimensions of the VP-110 are 30-7/16 (77.3 cm) Outside Diameter (OD) x 42-3/4 (108.6 cm) in height to the top of the outer drum bolt ring. The containment area is protected with a gasketed inner containment lid that is closed with twelve 1/2 (1.3 cm) bolts. A polyurethane insulation plug is encapsulated in 16-gauge carbon steel welded onto the drum lid (see Appendix 1.4.3). The gasketed drum lid is closed with eight 1/2 (1.3 cm) bolts and a standard drum ring. A gasket at the drum lids stiffening ring provides an additional barrier against water in-leakage.

The 110-gallon (416 liter) drum is strengthened with eight longitudinal stiffeners fabricated from 1-1/4 (3.2 cm) carbon steel square tubing equally spaced around the circumference of the drum.

A 16-gauge (1.5 mm) outer liner and a 16-gauge (1.5 mm) inner liner provide additional insulated radial stiffness to the drum. The volume between the inner liner and the 10-gauge (3.4 mm) containment body is filled with ceramic fiber insulation (see Appendix 1.4.4).

The Versa-Pac design does not include lifting or tie down devices. Handling is accomplished using standard drum handling equipment and/or a forklift. Shielding and pressure relief devices are not required for the Versa-Pac payloads. Plastic plugs located on the inner liner and the acetate plug located on the exterior of the package are designed to vent any combustion products generated by the insulation under Hypothetical Accident Conditions. The containment boundary is the containment area, the containment area blind flange and containment flat gasket seal. The containment area is attached to the structural components of the Versa-Pac using 12 equally spaced 1/2 (1.3 cm) bolts through a 1/4 (6.4 mm) connection ring and a 1/2 (1.3 cm) thick fiberglass thermal break connected to the structural frame. Bolts are torqued and the bolt/nut connection spot-welded to prevent potential loss of the connection.

Performance of the package to the required regulations and design criteria is demonstrated through the analytical evaluations and prototype testing discussed in the remainder of this section.

The package performs as required to the applicable regulations, assuring safe transport of the payload. Table 2-1 provides a summary of the evaluations performed and their results.

2.1.2 Design Criteria The Versa-Pac was designed to meet all of the performance requirements of 10CFR71 [4] for fissile materials. The Versa-Pac is manufactured under a quality assurance program that meets the requirements of 10CFR71, Subpart H [5]. All welding is performed by qualified personnel in accordance with AWS D1.1 [6]. All inspections are conducted by personnel qualified under ASNT-TC-1A [7], and/or for visual inspection, certified as an AWS certified welding inspector or assistant.

The containment boundary is defined as the containment area, its seal and blind flange. The structural design criteria for the packaging under the Normal condition are:

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021

• The packaging is maintained within the allowable temperature, pressure and stress ranges as stated in each Section and Table 2-1;

• VP The package outer diameter and the height are essentially maintained at their nominal as-built dimensions;

• VP-110 - The package outer diameter and the height are essentially maintained at their nominal as-built dimensions;

• Positive closure is maintained during transport;

• Moderators are evaluated inside the payload vessel (criticality control requirement);

• Measures are taken to ensure that chemical and galvanic reactions do not impair the function of the packaging (see Section 2.2.2);

• The package is stackable and meets the applicable regulations; and

• Performance and design of the packaging meets other minimum regulatory requirements for licensure.

The design criteria under Hypothetical Accident Conditions are:

• The packaging is maintained within the allowable temperature, pressure and stress ranges as stated in each Section and Table 2-1;

• VP The average OD of the packaging is maintained greater than 21.1 (53.6 cm) and the minimum height of the packaging is maintained greater than 33.6 (85.3 cm) under all conditions (criticality control requirement);

• VP-110 - The average OD of the packaging is maintained greater than 28.5 (72.4 cm) and the minimum height of the packaging is maintained greater than 41.8 (106.2) under all conditions (criticality control requirement);

Table 2-1 provides a summary of the structural evaluation, design criteria, and results of the evaluation.

Table 2-1. Evaluation Results Minimum Evaluation Evaluation Result Evaluation Criteria Factor of Safety (FS)1 or Design Margin (DM)2 Minimum package Versa-Pac is N/A 10CFR71.43(a) size 24 (61 cm) x 35 (89 cm) Package is acceptable Tamperproof One per package, Closure Ring N/A 10CFR71.43(b) feature Bolt Package is acceptable 110 Gallon Versa-Pac uses 20 bolts to secure the packaging & N/A Positive Closure 10CFR71.43(c) the 55 Gallon Versa-Pac uses Package is acceptable 16 bolts 2-3

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 2-1. Evaluation Results Minimum Evaluation Evaluation Result Evaluation Criteria Factor of Safety (FS)1 or Design Margin (DM)2 The materials do not react Chemical & chemically, and galvanic N/A 10CFR71.43(d)

Galvanic reactions reactions are acceptable over Package is acceptable the packaging life N/A Lifting N/A 10CFR71.45(a)

Package is acceptable N/A Tie down N/A 10CFR71.45(b)(1)

Package is acceptable Foam maximum expansion Heat

~0.004 (0.1 mm)

(Differential thermal Yield strength FS ¥ Stress developed ~ 0 psi in both expansion) foam and steel components N/A Steel yield strength Heat Package uses a de-coupled Foam compressive FS ¥ (Thermal Stress) design that minimizes thermal strength stresses Packaging temperature = -40°F Minimum allowable, -40°F Cold FS = 1.0

(-40°C) (-40°C)

Reduced External Effective pressure differential = Containment rated to FS = 1.3 Pressure 11.2 psig (77 kPa gauge) 15 psig (103 kPa gauge)

Increased External Effective pressure differential = Containment rated to FS = 1.7 Pressure 9 psig (62 kPa gauge) 15 psig (103 kPa gauge)

No loss of containment, no loss N/A Transport Vibration 10CFR71.71(5) of packaging effectiveness Package is acceptable No effect on packaging N/A Water Spray 10CFR71.71(6) effectiveness Package is acceptable Normal Condition No effect on packaging N/A 10CFR71.71(7)

Free Drop effectiveness Package is acceptable 10CFR71.71(9)

Compression 623 psi (4.3 MPa) FS = 25.7 steel yield strength No effect on packaging N/A Penetration 10CFR71.71(9) effectiveness Package is acceptable Hypothetical Accident Condition No effect on packaging N/A 10CFR71.73(1) and (3)

Free Drop and effectiveness Package is acceptable Puncture Drop 2-4

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 2-1. Evaluation Results Minimum Evaluation Evaluation Result Evaluation Criteria Factor of Safety (FS)1 or Design Margin (DM)2 10CFR71.73(4)

Hypothetical Maximum payload vessel Maximum allowable DM = 71 °F Accident Condition temperature 429°F payload/seal temperature = FS = 1.16 Fire 500°F Fissile Immersion No in-leakage 10CFR71.73(5) N/A Immersion No in-leakage 10CFR71.73(6) N/A Notes:

1. The Factor of Safety is defined as the ratio of the allowable to the actual, rounded down the nearest tenth.

2. The Design Margin is defined as the allowable minus the actual.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.1.3 Weights and Centers of Gravity The weight of each model of the Versa-Pac is provided in Table 2-2. The allowable payload weight of the VP-55 is 350 lb (158 kg) and the maximum gross weight of the VP-55 is 750 lb (340 kg) per the drop-test report listed in Reference [8]. The center of gravity of an empty VP-55 is located approximately 20 (51 cm) from the absolute base of the package along a vertical axis in the geometric center of the package. The center of gravity of a loaded package will shift downward by approximately 1 (2.5 cm). The center of gravity of an empty VP-110 is located at approximately 18 (46 cm).

Table 2-2. Versa-Pac Shipping Package Gross Weights 55-Gallon Version - Model No. VP-55 Component Weight (kg) Weight (lb)

Versa-Pac Shipping Package (Nominal) 177 390 Maximum Payload 158 350 Maximum Gross Weight of Loaded Package 340 750 110-Gallon Version - Model No. VP-110 Component Weight (kg) Weight (lb)

Versa-Pac Shipping Package (Nominal) 321 705 Maximum Payload 119 260 Maximum Gross Weight of Loaded Package 439 965 2.1.4 Identification of Codes and Standards for Package Design The Versa-Pac is a Type A fissile package based on the maximum U-235 payloads outlined in Section 1.1. The 1S/2S UF6 cylinder contents are limited per the requirements in Tables 1-5 and 1-6.

The Versa-Pac was designed to meet the requirements of 10CFR71 [4] and IAEA Regulations for the Safe Transport of Radioactive Material, SSR-6 [9].

Fabrication and the assembly of the Versa-Pac are conducted in accordance with Daher-TLI Quality Assurance Program [10] and normal shop Standard Operating Procedures. Welding shall be performed by qualified personnel using approved procedures in accordance with AWS D1.1

[6].

Testing and inspection of the Versa-Pac Shipping Packages will be conducted in accordance with Standard Operating Procedures in compliance with the appropriate code, such as ASNT, ASME and AWS.

Maintenance and use of the Versa-Pac Shipping Package shall be conducted in accordance with Section 7.0, Operating Procedures and Section 8.0, Acceptance Tests and Maintenance Program and the Certificate of Compliance.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.2 Materials 2.2.1 Mechanical Properties of Materials The mechanical material properties used to evaluate the Versa-Pac performance are provided in Table 2-3. The thermal material properties used to evaluate the Versa-Pac performance are provided in Section 3.2.1.

2.2.2 Chemical, Galvanic Reactions and Other Reactions The compatibility of materials used to fabricate the Versa-Pac and the combination of these materials has been demonstrated not to experience significant material loss due to chemical and galvanic reactions [11].

There are two combinations of Versa-Pac materials of construction that have the potential for galvanic reaction. The first combination is steel, primer, ceramic fiber insulation, and polyurethane foam insulation. The second combination is steel and the payload. Other packages have successfully used this combination of materials without galvanic reactions and have done accelerated corrosion tests to support the combined use.

All of the insulation materials used in the construction of the Versa-Pac container have low chloride content. The fiber insulation used has been tested for its corrosive action on steel with acceptable results [11]. Therefore, the combination of materials is acceptable for use.

The payload material is pre-packaged to limit contact with the containment area. Therefore, a galvanic reaction with the payload is not considered credible. However, pre-shipment and maintenance inspections would identify any corrosion due to contact with the payload well before the structural integrity of the containment area would be compromised.

Additionally, the contents and plastic pre-packaging materials do not produce significant amounts of hydrogen gas by radiolysis, as the available decay to support the reaction is essentially zero.

The RTV (Silicone Rubber Compound) coated fibrous sleeve allows the permeation of gas, without passage of solids, to keep the containment at approximately atmospheric pressure.

For the 1S/2S cylinder contents, the potential of hydrofluoric (HF) acid contamination is minimal.

Prior to loading into the Versa-Pac, all 1S/2S cylinders are cleaned to be free of chemical contamination. Each 1S/2S cylinder is packed with proper shoring/cribbing to prevent shifting and are supported during the NCT and HAC free drop events. The weight of a single fully loaded 1S and 2S cylinder are restricted to a maximum gross weight of 2.75 lb (1.2 kg) and 9.1 lb (4.1 kg),

respectively (Ref. [14], Table 4). Since the mass of the 1S/2S cylinders are small and are supported within the package, the cylinders are expected to survive both NCT and HAC.

Therefore, the inleakage of water into the container holding the UF6 material and thus generation of HF acid is not a credible event. However, in the event of cylinder surface HF contamination, the corrosion of the Versa-Pac packaging components would not result in the release of fissile material.

Therefore, interactions among contents, packaging materials of construction and packing material satisfy the requirements of 10 CFR 71.43(d) [4].

2.2.3 Effects of Radiation on Materials The radiation produced by the authorized payloads is very low. The packaging materials used (steel, rigid polyurethane insulation products, ceramic fiber insulation products, silicone rubber, 2-7

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 fluorocarbon) do not undergo significant changes in properties or performance due to their exposure to the authorized payloads.

Table 2-3. Mechanical Properties of Materials Carbon Steel Plate and Property/Material Carbon Steel Bolts Note 1 Sheet Note 1 Density (lb/ft3) 491 [12] N/A Thermal Expansion Coefficient (in/in/F) {9.22 x 10-6} N/A Min Yield Strength (psi x 1,000) {36} {81}

Min Tensile Strength (psi x 1,000) {58} {105}

Elongation in 2 (%)

{21*} {14}

• Elongation in 4D (%)

Property Impact Absorbing Foam Insulation Density (lb/ft3) 5.0 - 11.0 (Per Table 1-7)

Nominal Thermal Expansion Coefficient (in/in/F) 3.4 x 10-5 [13]

Compressive Strength (psi) 85 - 300 (Per Table 1-7)

Notes on Table 2-3:

1. Information provided in {brackets} is an average or nominal for the material used and is provided for comparison purposes only, as it is not used in any evaluation presented for the packaging.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.3 Fabrication and Examination 2.3.1 Fabrication The Versa-Pac is fabricated using Daher-TLI Standard Operating Procedures and Fabrication Control Records to document each step of the fabrication process (i.e., cutting of material, fitting, welding, and other special processes). The Fabrication Control Records (FCR) become a part of the permanent Quality Assurance Record for the package. All welding is conducted in accordance with approved procedures, which are in compliance with the applicable code such as AWS D1.1 [6]. All insulation materials are procured in accordance with the requirements in Appendices 1.4.3, 1.4.4, and 1.4.5.

A typical fabrication sequence for the Versa-Pac Shipping Package begins with the cutting and forming of the individual components, which is carried out through the use of a Route Sheet system which provides the preparation group the details for all items. These items are inspected and once approved, released for production to begin the process of manufacturing the Versa-Pac.

The Fabrication Control Record (FCR) provides sequenced steps for the manufacturing of the Versa-Pac. These individual sequences give the quality assurance and production departments the instructions, standard operating procedures, welding procedures and inspection hold points for proper fabrication of the package.

Each sequence must be completed in order and the FCR step signed and dated by the individual responsible for that work, prior to moving to the next sequence. The FCR allows for QA or the customer to insert additional hold points at any location in the production process.

2.3.2 Examination All non-destructive examinations methods utilized in the fabrication of the Versa-Pac Shipping Package, are conducted in accordance with Daher-TLI Standard Operating Procedures, which are in accordance with appropriate codes, such as ASME [14] and AWS D1.1 [6] and/or D1.3 and applicable engineering specifications. Section 8 of this report specifies the requirements for fabrication acceptance and maintenance examinations of this package.

2.4 General Requirements for All Packages 2.4.1 Minimum Package Size The smallest overall dimension of the VP-55 is 22-1/2 inches in diameter and the smallest overall dimension of the VP-110 is 30-7/16 inches (77.3 cm) in diameter. The Versa-Pac thereby complies with the minimum package size requirement of 10 CFR 71.43(a) [4].

2.4.2 Tamper-Indicating Feature The Versa-Pac utilizes the outer drum ring closure bolt for installation of tamper indicating devices, typically individually numbered seals.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.4.3 Positive Closure The primary containment is closed by use of a gasketed 1/2 (1.3 cm)-thick blind flange with 12 carbon steel clad 1/2 (13 mm) bolts, flat washers, and lock washers. The outer opening of the Versa-Pac is closed utilizing a reinforced insulated drum cover initially bolted through a gasketed surface with 4 carbon steel clad 1/2 (13 mm) bolts and flat washers on the VP-55 and 8 bolts on the VP-110. In addition, the standard drum closure ring with a 5/8 (16 mm) bolt. All closure bolts are torqued at 60 lb-ft (81.3 Nm).

2.5 Lifting and Tie-down Devices 2.5.1 Lifting Devices The Versa-Pac may be handled by normal industry standards for the safe movement of drums.

Such equipment might include specifically designed devices, forklifts, pallet jacks or other methods as determined by the user. However, the Versa-Pac does not utilize any specific device or attachment for lifting.

2.5.2 Tie-down Devices There are no specific provisions for tie-down of the Versa-Pac.

2.6 Normal Conditions of Transport (NCT)

The Versa-Pac meets the standards specified by 10 CFR 71 [4] when subjected to the conditions and tests required. The effectiveness of the package is maintained throughout all Normal Conditions of Transport.

Full-scale prototypes of both versions of the Versa-Pac Shipping Package were first tested in accordance with the (Structural) requirements specified by 10 CFR 71.71, Normal Conditions of Transport, and 10 CFR 71.73, Hypothetical Accident Conditions. Table 2-4 provides a matrix of all testing performed to certify the Versa-Pac design. The NCT testing program is further discussed in Section 2.7, where the NCT test is the precursor to the HAC test sequence.

Complete post-test measurements along with full photographic and written documentation is included in References [15], [16], [3] and [8].

An evaluation of the High-Capacity Basket (HCB) during NCT is provided in Appendix 2.12.3.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 2-4. NCT and HAC Test Matrix Test Test Description Test Date Reference Program #

1 Immersion Test July 2008 [17]

2 NCT and HAC Certification Test Series March [15]

Series 1 1A NCT 4' (1.2 m) Top End Drop 2009 1B HAC 30' (9 m) Top End Drop 1C HAC 40 (1 m) Puncture - Side Series 2 2A NCT 4' (1.2 m) Side drop 2B HAC 30' (9 m) Side Drop 2C HAC 30' (9 m) Dynamic Crush - Side Series 3 3A NCT 4' (1.2 m) C.G. Over Drum Ring 3B HAC 30' (9 m) C.G. Over Drum Ring 3C HAC 30' (9 m) Shallow Angle Drop 3D HAC 40 (1 m) Puncture - C.G. Over Drum Ring 3 Shallow Angle Drop Tests September [16]

1-55-A NCT 4 (1.2 m) Shallow Angle Drop (slap down) 2009 1-55-B HAC 30 (9 m) Shallow Angle Drop (slap down) 1-55-C HAC 40 (1 m) Puncture - C.G. Over Drum Ring 4 NCT Penetration and Stacking Tests December [18]

2009 5 5 Pipe Container Drop Tests October [3]

9.1 HAC 30 (9 m) Shallow Angle Drop (slap down) 2015 9.2 HAC 30' (9 m) Top End Drop 9.3 HAC 30' (9 m) C.G. Over Corner Drop (pipe cap) 6 NCT and HAC Test Series at 750 lb Max Gross Weight October [8]

2.1 HAC 4' (1.2 m) C.G. Over Drum Ring 2017 2.2 HAC 30' (9 m) C.G. Over Drum Ring 2.3 HAC 30' (9 m) Dynamic Crush - Side 2.4 HAC 40 (1 m) Puncture - Lid Center Note: The packages used for the test series were fabricated as specified by the packaging drawings provided in Appendix 1.4.1.

2.6.1 Heat 2.6.1.1 Summary of Pressures and Temperatures The peak payload temperature of the packaging is 176°F (80°C), under Normal Conditions of Transport (see Section 3.3.1.1). The material properties of the packaging remain essentially nominal at this temperature. This is well below the maximum allowable temperature of 600°F (316°C) (defined in Section 3.1.3) for the contents. The Versa-Pac containment is rated for a maximum pressure of 15 psig (205 kPa), however, the silicone-coated fiberglass gasket of the Versa-Pac allows gases to permeate through, but not solids, to maintain near atmospheric pressure. Therefore, the maximum normal operating pressure is near atmospheric pressure.

2.6.1.2 Differential Thermal Expansion The Versa-Pac is constructed of steel and insulation components. Due to their relatively high thermal conductivity, and the relative uniformity of the heat application, the steel components do not independently develop significant stresses due to differential thermal expansion.

The blanket insulation used is compressible, and therefore is not damaged by thermal expansion effects.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 The linear thermal expansion coefficient of the rigid foam insulation is approximately four times that of the steel; therefore, it is possible that the foam insulation expands more than the steel shell. If the entire volume of the foam increases in temperature from 72°F (22°C) to the peak steady state surface temperature of 144°F (62°C), the average maximum linear differential thermal expansion of the foam is about 1/16. However, due to the cyclic loading of the insulation, the actual volume of foam at 144°F (62°C) is limited to less than 15% of the total foam volume and a more realistic estimate of the expansion is about 1/240 (0.1 mm). These very small expansion lengths are absorbed by the microstructure of the foam at the steel surface and by the allowable tolerances on the parts themselves. Therefore, no significant stresses are generated as a result of differential thermal expansion.

2.6.1.3 Thermal Stress Calculations Due to the decoupled design of the packaging, thermal stresses generated by the packaging are negligible.

2.6.1.4 Comparison with Allowable Stresses Not applicable.

2.6.2 Cold At an ambient temperature of -40°F (-40°C) with no insolation and zero decay heat generated by the contents, the package attains a uniform temperature of -40°F (-40°C). At this temperature, the foam insulation compression strength and compressive modulus are increased. The increased foam (top and bottom of the package) strength and modulus result in a stiffer package response under drop conditions, and therefore more of the load is transferred to the containment boundary on impact. Also, the carbon steel components may be brittle below -20°F (-29°C). Performance testing of the package was completed at low temperature, demonstrating that the packaging performs as required under cold conditions.

No observable differences in damage were noted by comparison of prototype testing of the package at normal ambient temperatures to the performance testing conducted at low temperatures. Therefore, low temperature effects have little impact on the Versa-Pac performance.

2.6.3 Reduced External Pressure Per 10 CFR 71.71(c), a reduced external pressure of 25 kPa (3.5 psi) absolute must be considered. Per Section 3.3.2, the maximum normal operating pressure (MNOP) is atmospheric (101 kPa, 14.7 psia). Therefore, a reduced external pressure of 25 kPa results in a net internal pressure of 11.2 psig (77 kPa gauge).

In addition, para. 621 of SSR-6 requires that the VP-55 be capable of withstanding a net internal pressure of MNOP plus 95 kPa (13.8 psi) for air transport. As the MNOP for the Versa-Pac is atmospheric, the max pressure differential for air transport is 95 kPa (13.8 psi). Both resultant pressures required by 10 CFR 71 and SSR-6 are within the containment design pressure of 15.0 psig (103 kPa gauge). Therefore, the Versa-Pac satisfies the reduced external pressure requirements.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.6.4 Increased External Pressure Per 10 CFR 71.71(d), an increased external pressure of 140 kPa (20 psi) absolute must be considered. Per Section 3.3.2, the MNOP is atmospheric (101 kPa, 14.7 psia). Therefore, an increased external pressure of 140 kPa results in a net internal pressure of 62 kPa gauge (9 psig).

This pressure differential is within the containment design pressure of 15.0 psig (103 kPa gauge).

Therefore, the Versa-Pac satisfies the increased external pressure requirement.

2.6.5 Vibration Vibration incident to transport does not produce settling, compaction or a loss of structural cohesion for any of the materials used in the packaging. Vibrational compaction of the payload does not impact the performance of the packaging, since the criticality evaluation (see Section 6) applies a variable payload density up to the theoretical limit to evaluate the optimum condition.

Vibration testing conducted on the outer drum during the performance design qualification test as set forth in 49 CFR 178.608 [19] were successfully performed with past experience indicating no failure to the drum ring closure. In addition, the Versa-Pac includes an additional bolted closure through the top lid attached to the internal structure. This bolted closure utilizes 1/2 bolts and locking washers that are torqued to a prescribed rating of 60 lb-ft. to prevent the loss of the bolts during transportation. Thus, normal vibration incident to transport does not impact the performance of the Versa-Pac.

2.6.6 Water Spray A one-hour water spray simulating rainfall at a rate of 2 in/hr. has no effect on the Versa-Pac, as the outer vessel is designed to withstand exterior pressure loads much higher than those applied by the water spray.

The Versa-Pac utilizes multiple seals to prevent the loss or dispersal of its contents. Because it is clear that the water spray test has no effect on the package or contents, it was not conducted during the performance test sequence.

2.6.7 Free Drop Per regulatory requirement, the package must maintain its integrity and effectiveness when subjected to a free drop from a height of 4 feet (1.2 meters) onto a flat, essentially unyielding horizontal surface. Although the damage from a 4-foot free drop results in some local deformation of the transport unit, the deformation is well within the allowable specified for criticality safety and structural stability. Three different drop orientations were conducted and the results of all five normal condition performance tests of the Versa-Pac are provided in Reference [15] and [8]. A summary of the NCT free drop performance is documented in Section 2.7.1.

2.6.8 Corner Drop A free drop onto each corner of the package in succession, or in the case of a cylindrical package onto each quarter of each rim, from a height of 1 ft (0.3 m) onto a flat, essentially unyielding, horizontal surface. This test applies only to fiberboard, wood, or fissile material rectangular packages not exceeding 110 lb (50 kg) and fiberboard, wood, or fissile material cylindrical packages not exceeding 220 lb (100 kg). This test is not applicable to the Versa-Pac packaging, since the minimum tare weight is 390 lb (177 kg).

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.6.9 Compression The primary load bearing members of the Versa-Pac are the steel 55 or 110-gallon drum shell, the vertical stiffeners, and the inner liner. These components, when assembled as a unit, can be analyzed as an axial member in compression. Assuming the metal thickness is 0.036 and 0.05 for the drum and inner liner, respectively, and using 1-1/4 x 1-1/4 x 0.12 for conservatism (the actual thicknesses are 0.06, 0.0598, and 0.135 respectively), the load-bearing cross-sectional area is approximated as:

(22.5 .)(0.036 in.) + (19.25 .)(0.05 in.) + 4(1.25 .! 1.01 .! ) = 7.738 .! (50 ! )

Five times the weight of the package is:

(5)(965 ) = 4,825 (2189 )

The compressive stress on the steel members is:

4,825 7.738 .! = 623 (4.3 )

The margin of safety against compressive failure is:

. . = E36,000F623G 1 = 56.7 For empty Packaging Five times the weight of the packaging is:

(5)(390 ) = 1,950 (885 )

The compressive stress on the steel members is:

1,950 7.738 .! = 252 (1738)

The margin of safety against compressive failure is:

. . = E36,000F252G 1 = 141.9 The structural members of the Versa-Pac are comprised of a variety of thicknesses of steel components, although when combined through the process of manufacturing act in conjunction with one another to produce an exceptionally strong unit. To further demonstrate that the Versa-Pac meets the requirements set forth in 10 CFR 71.71(c)(9) [4], the Versa-Pac was subjected to a load greater than 5 times the weight of the package for a period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> without any damage.

The VP-55 was tested, and the results are provided in Reference [18]: NCT Versa-Pac Test Report for Compression and Penetration.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Conclusion Based upon the calculations providing a large margin of safety against compressive failure and the physical testing performed using the previously tested VP-55 described above and reported in Reference [18] NCT Versa-Pac Test Report for Compression and Penetration, the Versa-Pac meets and exceeds the requirements specified in 10 CFR 71.

2.6.10 Penetration The Versa-Pac was subject to the penetration test described in 10 CFR 71.71(10) [4]. The test was performed using a 1.25-inch diameter steel bar weighing 13.2 lb (6 kg) and dropped from a height of 40 inches (1 meter) onto several different areas of the test package considered to be the weakest parts of the package without measurable damage at the impact point. These results are supplied in Reference [18] NCT Versa-Pac Test Report for Compression and Penetration.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.7 Hypothetical Accident Conditions (HAC)

Full-scale prototypes of both versions of the Versa-Pac Shipping Package were first tested in accordance with the (Structural) requirements specified by 10 CFR 71.71, Normal Conditions of Transport, and 10 CFR 71.73, Hypothetical Accident Conditions.

The compliance testing demonstrated:

• The Versa-Pac provides sufficient thermal protection to prevent the internal temperature of the payload container from exceeding the maximum design temperature of the containment boundary (500°F) during and following HAC,

• The average OD of the package and the required package height are maintained under HAC, and

• Containment of the payload is maintained.

Therefore, the Versa-Pac provides adequate protection to the payload during HAC as defined by 10 CFR 71.73 [4].

An evaluation of the High-Capacity Basket (HCB) during HAC is provided in Appendix 2.12.3.

2.7.1 Free Drop Full-scale representatives of the VP-55 and VP-110 containing a simulated payload were subjected to a variety of sequenced drops, punctures, shallow angle drops and crush test, specified by 10 CFR 71.71 and 10 CFR 71.73 [4]. Table 2-4 provides a matrix of free drop tests performed to certify the Versa-Pac design. Complete measurements along with full photographic and written documentation is included in References [15], [16], [3] and [8].

Test Program #2 - Series 1 The VP-55 and VP-110 test program is described in Reference [15]. The first drop series included the NCT 4 top end drop (1A) followed by the HAC 30 drop (1B) in sequence. This series also includes the HAC side puncture (1C). Prototypes of both the VP-55 and VP-110 were test with the final test article utilizing the VP-110 design. All drop tests were performed on the same 70-ton pad which is 10 x 10 x 10 deep reinforced with a grid of 3/4 re-bar spaced on 12 center and capped with an 8 x 10 x 1 thick steel plate which is embedded to the surface of the concrete and secured to it with fourteen 1-1/2 diameter x 16 long bolts. A quick-release mechanism was used to release the prototypes from the drop height without imparting rotational or translational motion to the prototype. For the puncture drop, a puncture ram was welded to the test pad. The ram is a 6 diameter by 18 long right circular cylinder, fabricated from mild steel and welded to the pad reinforcement plate. The solid steel plate used for the dynamic crush test weighs 500 kg and is 1m by 1m in cross section. The tests were video-taped and photographed, and post-drop damage measurements were recorded after each drop.

In order to determine the worst-case initial temperature conditions for the drop tests, the performance characteristics of the primary Versa-Pac fabrication materials were evaluated. The primary structural and sealing materials include carbon steel, polyurethane foam, and silicone rubber. Because carbon steel may exhibit brittle failure mechanisms at temperatures below 0°F and the other materials are essentially unaffected over the design temperature range, the initial condition temperature selected is -20°F. For consistency with the minimum design operating temperature specified by the regulations, the impact testing initial ambient condition selected is -40°F.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 The payload utilized for the drop test series consisted of a 30-gallon drum that was filled with approximately 260 lb of different size gravel with an additional 1 to 1-1/2 lbs. of loose play sand, which was placed on the top of the 30-gallon drum, combining for a test payload of 260 lbs. The blind flange was secured by tightening the bolts to an initial torque of 40 lb-ft. The decay heat generated by the contents is negligible; therefore, heat generated by the contents was not simulated. The Versa-Pac was then subjected to an ambient air temperature of approximately -40°F for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Upon removal from the conditioning chamber, the exterior skin of the shipping package recorded a temperature of -28°F at time of transport to the test pad.

Test Program #2 - Series 2 The second drop test series included the NCT 4 side drop (2A), HAC 30 side drop (2B) and HAC 30 dynamic crush test (2C) in sequence. Both previously dropped packages were inspected and measurements of height and diameter recorded on new testing records. The payloads were identical to the original test series, with 1.5 pounds of sand placed on top of and around the payload as before. The test articles were fitted with new 1/2-inch thick inner containment flanges with 3/8-inch-thick neoprene sponge rubber pads affixed to the inside of the inner flange lid prior to installation. The torque of the inner containment bolts was also increased to 60 lb-ft for a better seal on the 1.8-inch-thick silicone rubber coated fiberglass gasket. The outer container lid was put into place and bolts torqued to 60 lb-ft. The test articles were then placed in the cooling chamber for 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> prior to the new drop tests.

With changes made to the inner blind flange closure design; increasing the thickness of the flange, increasing the torque of the bolts and reinstalling the containment flange pad, the Versa-Pac Shipping Package successfully completed the drop test evaluation series.

Test Program #2 - Series 3 The third drop test series included the NCT 4 C.G. over corner drop (3A), HAC 30 C.G. over corner drop (3B), HAC 30 shallow angle drop (3C) in sequence and HAC 1-meter puncture test (3D). The test article from Series 2 was repaired and resealed for the drop sequence.

With changes made to the inner blind flange closure design, increasing the thickness of the flange, increasing the torque of the bolts and reinstalling the containment flange pad, the Versa-Pac Shipping Package successfully completed the drop test evaluation series.

Test Program #3 This test program is described in Reference [16] and was performed on the VP-55 design to evaluate shallow angle drop orientations (slap down). Worst case drop orientations were determined by evaluating the results of previously tested drum type packages presented in References [20] and [21]. The most damaging configuration was further demonstrated through a preliminary series of tests conducted on both the VP-55 and VP-110 designs during March 2009 (Test Program #2, [15]). Following the test sequence, the test article was inspected and the outer closure was maintained with no openings, tears or failure noted that would lead to the loss of material from containment.

Test Program #5 The 5-inch pipe container (VP-55-2R) drop test program is described in Reference [3]. The drop test sequences were chosen in order from least severe to most based upon historical drop testing of other specimens, industry experience, and engineering experience. The test sequence included slap-down, end drop on pipe cap, and C.G. over top corner. The results of the test series show that the VP-55-2R is capable of maintaining the safe geometry of the confinement vessel without failure or loss of material.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Test Program #6 This drop testing program was performed to increase the minimum VP-55 payload capacity to 350 lb. This program included both NCT and HAC Free Drops and is presented in Reference [8].

The same test article was used for both the NCT and HAC test sequence. To achieve the increased payload capacity, the test article was loaded with sand and steel blocks. Ten pounds of flour and 4 ounces of fluorescein were also added as indicators. The NCT and HAC drop tests were performed in sequence. First, in an effort to loosen or dislodge the drum closure ring, the NCT 4-foot free drop was performed with the package's C.G. positioned over the drum lid closure ring bolt. Second, the package was dropped from 30 feet in the top C.G. over lid drum ring 180° from the closure bolt. Third, the dynamic crush test was performed by positioning the package on the drop test pad rotated 90 degrees from the previous point of impact. Fourth, the package was subjected to the 40-inch puncture test by dropping the package top end down onto the center of the lid.

Following each test, the package was inspected with a black light and no evidence of fluorescein around the lid closure was noted. Therefore, containment of material was maintained. Mechanical damage included localized tearing of the drum ring. However, the drum ring remained in place and no failure of the lid closure bolts occurred.

2.7.1.1 End Drop To satisfy the requirements of 10 CFR 71.73(c)(1) end drop, two test programs evaluated the performance of the package when subjected to the end drop.

Test Program #2 - Series 1 After cooling, the test article was positioned with the top end of the package positioned over the test pad at an angle of 0 degrees so as to impact the container directly onto the top surface of the package [15]. This drop test series was intended to test the top closure of the package and the internal containment closure components and to validate that the changes made to the inner containment flange would prove to correct the loss of materials previous found during the original drop testing.

NCT 4 Top End Drop This drop was made from a height of 4 onto the target pad (Test 1A), and the external damage was recorded and documented with both video and still photography. As result of the impact, no visible damage was noted. All welds, closures and bolts remained intact. The package was not opened after the Normal Condition Drop but was prepared for the 30 HAC Drop.

HAC 30 Top End Drop Following the Normal Conditions Drop, the package was positioned for the HAC 30 drop onto the same surface and orientation of 0 degrees (Test 1B). Post-drop inspection documented that the overall height of the package was reduced by 7/16 inch and that the drop test did not affect the diameter. All welds, closures and bolts remained intact.

Prior to opening the test article, the bolt torque of the outer closure was measured and found to be between 20 to 80 lb-ft. with all bolts intact. After opening the package photographs were taken and the interior well surfaces inspected with no damage found. The new thicker blind flange remained flat, sealed and no loss of payload contents were found outside the inner containment area. The bolts of the interior containment were torqued and found to be at a torque of 30 to 50 lb-ft. The gasket and payload were in good condition.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Test Program #5 A new pipe container is fabricated per drawing VP-55-2R and tested without the protection provided by the Versa-Pac container. Steel shot was used to simulate the contents with sufficient ullage to induce a piston action on the pipe cap during impact [3].

HAC 30 Top End Drop The test article was raised to a height of 30 feet as measured from the lowest point of the pipe container (Test 9.2). The pipe container was dropped in a vertical position directly on the pipe cap. After the drop, the pipe container was examined and no measurable or release of contents was visible.

2.7.1.2 Side Drop To satisfy the requirements of 10 CFR 71.73(c)(1) side drop, one test program evaluated the package performance when subjected to the side drop event.

Test Program #2 - Series 2 This drop series was designed to challenge the bolted closure and seal system during the side drop by targeting the drum ring closure bolt. After cooling, the test article was positioned in a level horizontal position over the test pad [15].

NCT 4 Side Drop The initial drop was made from a height of 4 onto the target pad (Test 2A), and the external damage was recorded and documented with both video and still photography. The result of the impact to the exterior surface of the package showed that the closure bolt pushed into the package sidewall approximately 5/8 inch. No reduction in height or diameter occurred. All welds, closures and bolts remained intact.

HAC 30 Side Drop The same test article was positioned for the HAC 30 drop into the same horizontal surface as the NCT test in an effort to account for the effect of accumulated damage in the side drop orientation (Test 2B). Resultant damage from this drop accounted for a buckling around the closure bolt area and on the lid and a decrease in the diameter of 1 inch in the drum ring closure bolt impact direction. There was no loss of bolts or seal and all welds remained intact. The package was then subjected to the dynamic crush drop described in Section 2.7.2.

2.7.1.3 Corner Drop To satisfy the requirements of 10 CFR 71.73(c)(1) corner drop, three test programs considered the effects of the corner drop on the closure system of the package.

Test Program #2 - Series 3 This drop series was designed to challenge the package and containment bolted closure and seal systems of the package when positioned in the center of gravity over drum closure ring orientation.

After cooling, the test article was positioned with the center of gravity impact to be through the package bolt closure over the test pad [15].

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 NCT 4 Center of Gravity Over Corner Drop The normal condition center of gravity drop from a height of 4 through the bolted closure at an angle of 57 degrees was recorded and documented using both video and still photography (Test 3A). The impact resulted in a deformation on the closure bolt area with measurements of 1-3/16 inch deep by 2-1/4 inches long. All welds, bolts and closures remained intact.

HAC 30 Center of Gravity Over Corner Drop The package was repositioned in the same attitude of 57 degrees so as to impact the identical area tested in 3A above over the test pad at a height of 30 from the lowest point of the package (Test 3B). The impact resulted in a deformation of 2-9/16 deep by 20-1/2 inches long. All welds, bolts and closures remained intact. The package was then readied for the HAC oblique (Shallow) angle drop.

Test Program #5 A new pipe container is fabricated per drawing VP-55-2R and tested without the protection provided by the Versa-Pac container. Steel shot was used to simulate the contents with sufficient ullage to induce a piston action on the pipe cap during impact [3].

HAC 30 Center of Gravity Over Corner Drop The test article was raised to a height of 30 feet as measured from the lowest point of the pipe container (Test 9.3). The pipe container was dropped in the C.G. over corner position approximately 12.5° from the vertical position directly on the pipe cap. After the drop, the pipe container was examined and a dent measuring 1-1/2 x 3/8 at the point of impact with no measurable effect on the rest of the container or release of contents was visible.

Test Program #6 The purpose of this additional drop testing is to increase the allowable payload weight for the 55-gallon Versa-Pac to 350 lb [8]. The test subject was loaded with sand and steel blocks until the total package weight was 750 lb. Subtracting the 396-lb tare weight of the Versa-Pac Prototype

1. 2 from the gross weight, the tested payload weight was 354 lb. Testing was conducted on an unyielding surface under ambient temperature conditions.

NCT 4 Center of Gravity Drop The NCT corner drop was conducted by positioning the test article in the C.G. over corner in the top-down position and dropping onto a flat, essentially unyielding, horizontal surface, striking the drum ring closure bolt (Test 2.1). Damage during the 4-foot drop was observed at the corner of the package at the bolt connection of the drum ring. The drum ring and lid deformation was localized at the point of impact and did not significantly change the overall dimensions of the package. No release of material or breach of containment of the package was observed.

HAC 30 Center of Gravity Drop The HAC corner drop was conducted by positioning the test article in the C.G. over corner in the top-down position and dropping onto a flat, essentially unyielding, horizontal surface, striking the drum ring closure 180° from the NCT drop damage (Test 2.2). The deformation during the 30-foot drop was observed at the top corner of the package at the drum ring and the drum lid reinforcing plate. Observations of the deformed corner showed localized tearing where the drum ring impacted the pad. However, the drum ring remained intact and in position with no failure of the lid closure bolts noted. No release of material or breach of containment of the package was noted.

This drop was followed by the dynamic crush test described in Section 2.7.2.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.7.1.4 Oblique Drop To satisfy the requirements of 10 CFR 71.73(c)(1) oblique drop, three test programs considered the effects of slap down on the packages performance.

Test Program #2 - Series 3 The test article used in this test was previously used in the C.G. over corner described above and was positioned with the C.G. through the bolted connection at an angle of 56 degrees from horizontal (Test 3C) [15]. The package was raised to the drop height of 30 feet-1 inch above the test pad surface from the lowest point of the package.

HAC 30 Shallow Angle Drop (Slap Down)

The damage to the package exterior surface produced deformation on the initial top closure measuring 2-5/16 inches deep with a 1-inch crumple in the lid. Secondary impact produced damage measuring 5 inches in length on the bottom rim of the test article. Diameter of the package was reduced in the direction of the impact area through the bolt by approximately 1 inch.

Before opening the outer closure, the torque was measured and found to be less than 20 lb-ft.

Photographs were taken and inspection of the inner well area found only minor deformation within the sidewalls of the well area. No other damage was found. The inner flange was flat and sealed with no loss of contents form the internal containment area. Bolt torque of the inner flange ranged from 20 to 40 lb-ft.

Test Program #3 The package was positioned over the test pad at 17 degrees from the horizontal position so that initial contact occurred on the top closure with the resulting secondary impact at the bottom of the package [16]. This drop was also intended to test the inner containment area closure system. The drop angle of 17 degrees was chosen based upon previous drop history and drop information found in References [20] and [21].

NCT 4 Shallow Angle Drop (Slap Down)

The package was positioned such that the lowest point of the package was 4 from the target surface (Test 1-55-A). The damage to the package exterior surface was minimal, with an area 7-1/4 long at the widest points on the top closure end and 5-3/4 in width at the bottom edge.

Minor indentation along the outer drum rolling hoops was also noted. Both flattened areas were approximately 1/4 in depth. There was no tearing or opening of the package.

HAC 30 Shallow Angle Drop (Slap Down)

The same test package was then positioned over the test pad at 17 degrees from the horizontal position with the lowest point of the package 30 from the target surface (Test 1-55-B). Damage to the package consisted of a small ripple in the middle of the outer drum lid with minor flattening of the outer drum rolling hoops. Additional damage to the top closure, initial impact area was noted, increasing the length of the NCT damaged area to 11-1/2 long by 3/8 deep. Additional damage to the bottom closure impact area with secondary impact damage was noted, increasing to 10 long by 1/4 deep. The bolt closure ring of the outer drum was pushed into the sidewall of the outer drum, producing a small tear in the drum sidewall material at the top rolling hoop, but due to the design of the package there was no breach or tearing of the Versa-Pacs inner liner, which is adjacent to the outer drum. The drum closure ring lug was also broken with the impact, but the top closure remained intact and secure due to the top closure bolts of the package. The package was then readied for a puncture test described in Section 2.7.3.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Test Program #5 A new pipe container is fabricated per drawing VP-55-2R and tested without the protection provided by the Versa-Pac container. Steel shot was used to simulate the contents with sufficient ullage to induce a piston action on the pipe cap during impact.

HAC Shallow Angle Drop (Slap Down)

The test specimen was dropped from a height of 30 feet, measured from the top of the target to the lowest point of the specimen at an angle of 15.9° from horizontal (Test 9.1). After the drop, the damage consisted of a 1-3/16 x 3/16 dent to the container cap and a 1-3/8 x 1/16 dent to the bottom plate. The damage did not reduce the function of the container to confine the contents.

No loss of material was noted.

2.7.1.5 Summary of Results The free drop test results provided information showing that the package design is capable of withstanding multiple impacts with only minor damage to the exterior surfaces. The complete drop test summary of results is discussed in detail in Section 2.7.8.

2.7.2 Crush To satisfy the requirements of 10 CFR 71.73(c)(2), two test programs considered the dynamic crush test and were performed to challenge the package closure system by placing the package on the test pad in a horizontal attitude. The crush plate was positioned to impact the package directly on both the closure and top flange region of the package.

Test Program #2 - Series 2 The crush test was performed on the test article that experienced both the NCT 4-foot side drop and the HAC 30-foot side drop in sequence [15].

HAC 30 Dynamic Crush - Side Impact The crush plate was suspended at an angle of 0 degrees directly over the test package and lifted to a height of 30 feet from the lowest point of the test plate to the top of the test package surface (Test 2C). Upon impact, the overall diameter of the package in the direction of the impact was reduced by 2-1/2 inches from its original shape at its maximum point. A gap of 1/4 inch by 1-1/4 inch long was documented at the drum lid to drum rim interface. Due to the design of the closure lid, a metal-metal interface was visible with no direct opening to the internal structure or seals. The gaskets were intact with minimal damage. The payload drum did exhibit some crumpling at the lid, but all of the payload materials remained within the drum and payload cavity as required. Upon inspection, the inner cavity showed no visible damage.

Test Program #6 The purpose of this test program was to increase the VP-55 payload capacity to 350 lb [8]. The crush test was performed on the test article that experienced both the NCT and HAC corner drops on the drum closure ring in sequence.

HAC 30 Dynamic Crush - Side Impact For this test, the VP-55 test article was laid on the test side opposite previous damage (Test 2.3).

The 1141 lb (517 kg) crush plate was raised 30 feet (9 m) from the side of the package surface.

The crush test resulted in flattening on both the side of the package resting against the ground and the side that was directly impacted by the crush plate. Localized deformation due to the edge 2-22

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 of the crush plate was also observed at the point of impact. No closure bolt failure was noted, the drum closure ring remained in position and no leakage of material was observed on the package outer surface.

2.7.3 Puncture To satisfy the requirements of 10 CFR 71.73(c)(3), prototypes of both the VP-55 and VP-110 were subjected to the puncture test in a variety of orientations including side, center of gravity through the bolt closure and lid center.

Test Program #2 - Series 2 The packages were lifted to a height of 41 inches above the top of the puncture ram, which was welded to the top surface of the drop test pad [15].

HAC 1 Meter Puncture Drop - Horizontal The suspended package was positioned level and horizontal (1 degree) so that the impact location was between two of the vertical stiffeners and in the middle of package (Test 1C). The test was recorded and documented using video and still photography. The deformation upon measurement was a maximum of 3/8 inch deep. The package sustained no tears as a result of the puncture drop.

HAC 1 Meter Puncture Drop - CG Over Drum Ring The package was positioned with the center of gravity through the bolted closure at an angle of 56 degrees from a height of 41 inches from the lowest point of the package to the top of the puncture pin (Test 3D). The drop test was recorded and documented using both video and still photography. The impact resulted in additional damage on the drum side at the closure bolt with a small separation of 1/4 inch by 3 inches long at the drum lid and drum rim interface. The opening was sealed by metal-metal contact between the flange and the drum lid insulation sheet metal cover and the top gasket material, which remained intact. The inner containment gasket was in good condition with only minimal damage to the outer closure gasket.

Test Program #3 The package was positioned with the center of gravity through the bolted closure at an angle of 56.5 degrees from a height of 41 inches from the lowest point of the package to the top of the puncture ram (Test 1-55-C) [16].

HAC 1 Meter Puncture Drop - CG Over Drum Ring After impact, the deformation of the test article was measured at an affected area of 8-3/8 wide with a diameter of 23 at the top of the closure area. There were no tears or opening of the package as a result of the puncture drop. The impact resulted in additional damage to the outer drum closure ring and lid interface with an impact deformation measuring 8-3/8 in diameter. The gaskets and internal containment cavity were found to be in good condition with no damage.

Test Program #6 The puncture test is the final test in the test sequence, which includes the dynamic crush test, to increase the VP-55 payload capacity to 350 lb [8]. For the HAC Puncture test, the VP-55 was dropped in the vertical lid down position such that the center of the lid would strike the puncture pin (Test 2.4).

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 HAC 1 Meter Puncture Drop - Vertical Lid Center The test was performed on the same package article that was dropped through the NCT and HAC Free Drop tests and the HAC Dynamic Crush test. The drum lid experienced a large local deformation, but the package was not breached. Also, the position of the outer drum ring was not affected such that the package height was not reduced. There was no leakage of material to the package outer surface.

2.7.4 Thermal A thermal test was not performed on the test prototype in its damaged condition following the drop test sequence. However, the package was analytically evaluated as indicated in Section 3. Based on testing of a similar package [17], the analytically calculated values are conservative.

2.7.4.1 Summary of Pressures and Temperatures The Versa-Pac was evaluated for HAC described in Section 3.4. The maximum temperature recorded at the payload cavity during the fire event was 429°F (221°C) at the top of the payload cavity, just below the polyurethane plug, as shown in Figure 3-16. This temperature is well below the maximum HAC allowable temperature of 600°F (316°C). The silicone fiberglass gasket of the containment allows for gas to permeate through to maintain near atmospheric pressure. The containment is rated for a pressure of 15 psi (103 kPa) gauge. In addition, the Versa-Pac features pressure plugs that will relieve any pressure build-up between the Versa-Pac inner and outer walls due to HAC.

To ensure the confinement of the fissile content, the structural performance of the 5-inch pipe is demonstrated via the bounding drop testing performed and detailed in Reference [3]. As stated above, the maximum temperature within the containment boundary of the Versa-Pac is 429°F (221°C). Thus, the temperature of the 5-inch pipe will be 429°F (221°C). Per Table 3-10 of Chapter 3, carbon steel is not expected to have a significant loss of thermal properties during NCT and HAC, as the temperature limit for carbon steel of 2600°F (1427°C) is well above this maximum experienced temperature. Since the 5-inch pipe can retain pressure, when the package heats up the pressure inside the pipe will increase slightly. Considering the pipe closed at 70°F (529.7°R) and heated to 429°F (888.7°R), the maximum pressure inside the pipe due to the increase in temperature is calculated using the ideal gas law as:

T! 888.7°R P! = P" = 14.7 psia = 25 psia = 10.3 psig T" 529.7°R The working pressure rating of standard 5-inch schedule 40 pipe and manufactured pipe cap is 580 psig. With the addition of the bottom plate, the pipe container forms a pressure retaining vessel. The maximum stress at the edge of the bottom plate [22], sxmax, is:

sxmax = $

x '!

= 955 psi

Where, a = 2.78 in, outside radius of bottom plate t = 0.25 in, thickness of bottom plate 2-24

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Comparing the maximum stress to the yield strength of 29,300 psi at 500°F for A36 carbon steel, the margin of safety is +30. Therefore, the ability of the 5-inch pipe to confine the fissile material will not be compromised due to the temperature increase from a fire accident.

2.7.4.2 Differential Thermal Expansion As discussed in Section 2.6.1.2, the materials used to fabricate the Versa-Pac and the arrangement of the packaging limit the effects of differential thermal expansion. No significant stresses are generated as a result of differential thermal expansion.

2.7.4.3 Stress Calculations Due to the decoupled design of the packaging, thermal stresses generated by the packaging are negligible.

2.7.5 Immersion - Fissile Material Moderator inleakage to the most reactive credible extent is assumed for the Versa-Pac and evaluated in Section 6.0. Thus, the fissile material immersion test is not required.

2.7.6 Immersion - All Packages A separate, undamaged specimen must be subjected to water pressure equivalent to immersion under a head of water of at least 50 ft (15 m). For test purposes, an external pressure of water of 21.7 lbf/in2 (150 kPa) gauge is considered to meet these conditions.

Test Program #1 As indicated in Reference [17], a similar damaged prototype was placed in an immersion chamber at 23 psig for 15 minutes. The package was removed from the immersion chamber with no damage to the outer structure. The outer drum lid was removed, and the inner vessel was inspected with no damage noted.

2.7.7 Deep Water Immersion Test This section is not applicable to the Versa-Pac Shipping Package.

2.7.8 Summary of Damage This section summarizes the condition of the package after each test sequence. Table 2-5 provides a summary of the test performed on the Versa-Pac and the final results. In all cases, the package results were acceptable and met the applicable acceptance standards. Table 2-6 provides a summary of the maximum damage resultant from all tests. These measurements are used as the basis for the NCT and HAC criticality safety models.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 2-5. Summary of NCT and HAC Test Results Test Test Description Results Reference Program #

1 Immersion Test Passed [17]

NCT and HAC Certification Test Series 1A NCT 4' (1.2 m) Top End Drop Series 1B HAC 30' (9 m) Top End Drop 1

1C HAC 40 (1 m) Puncture - Side 2A NCT 4' (1.2 m) Side Drop Series 2 2B HAC 30' (9 m) Side Drop Passed [15]

2 2C HAC 30' (9 m) Dynamic Crush - Side 3A NCT 4' (1.2 m) C.G. Over Drum Ring Series 3B HAC 30' (9 m) C.G. Over Drum Ring 3 3C HAC 30' (9 m) Shallow Angle Drop 3D HAC 40 (1 m) Puncture - C.G. Over Drum Ring Shallow Angle Drop Tests 1-55-A NCT 4 (1.2 m) Shallow Angle Drop (slap down) 3 Passed [16]

1-55-B HAC 30 (9 m) Shallow Angle Drop (slap down) 1-55-C HAC 40 (1 m) Puncture - C.G. Over Drum Ring 4 NCT Penetration and Stacking Tests Passed [18]

5 Pipe Container Drop Tests 9.1 HAC 30 (9 m) Shallow Angle Drop (slap down) 5 Passed [3]

9.2 HAC 30' (9 m) Top End Drop 9.3 HAC 30' (9 m) C.G. Over Corner Drop (pipe cap)

NCT and HAC Test Series at 750 lb Max Gross Weight 2.1 HAC 4' (1.2 m) C.G. Over Drum Ring Passed [8]

6 2.2 HAC 30' (9 m) C.G. Over Drum Ring 2.3 HAC 30' (9 m) Dynamic Crush - Side 2.4 HAC 40 (1 m) Puncture - Lid Center 2.7.8.1 Test Program #1 - Immersion Test A prototype of a similar package using the same closure system and structural design was subjected to hydrostatic testing after thermal testing with pressures that exceed the immersion test requirement [17]. The results of the test showed the containment closure system was in good condition with no damage. No damage to the outer drum reinforcement or inner cavity was noted.

No inleakage of water into the containment cavity occurred.

2.7.8.2 Test Program #2 - Versa-Pac NCT and HAC Drop Testing Based upon the information obtained from prototype drop testing, design changes were made to increase the blind flange (PD) thickness to 1/2 inch, and the inner containment closure bolt torque was increased to 60 lb-ft [15].

Test Series #1 The series of test conducted included a 4-foot top end drop, a 30-foot top end drop and a horizontal side puncture drop. Prior to testing, all closure bolts recorded a torque of 60 lb-ft. Prior to opening of the test package, the outer bolts were torqued, and readings were found to be between 20 and 80 lb-ft. with all bolts intact. After opening the test article, photographs were taken and the interior well surfaces inspected with no damage found. The flange remained flat, sealed 2-26

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 and no loss of the payload contents was found outside the containment cavity. The bolts of the inner blind flange were torqued and found to have readings of between 30 to 50 lb-ft. The gaskets and payload cavity were in good condition. Following the side puncture, deformation in the side of the test article was measured at a depth of 3/8 inch. There were no tears as a result of the puncture drop.

Test Series #2 The test article series of drops included a 4-foot horizontal side drop, a 30-foot horizontal side drop and a 30-foot crush plate side drop. Although the outer drum ring became dislodged, the package remained closed and in place due to the additional top closure bolts. The outer closure bolts of the top cover were torqued and recorded a reading of 25 lb-ft. Upon removal of the outer lid, an inspection revealed a slight interior wall deformation in the upper plug well of the package.

There was no loss of contents. The containment flange was in good condition and the bolts recorded a torque of 25 lb-ft. Gaskets were in good condition. The containment lid exhibited some bending from the piston action of the internal gravel and sand acting on the blind flange. Upon removal of the inner containment payload, a visual inspection was conducted with no damage shown within the inner containment cavity.

Test Series #3 This series consisted of a 4-foot center of gravity drop, a 30-foot center of gravity drop, a 30-foot shallow angle drop, and a center of gravity puncture drop. Upon completion of these drops, the test package outer closure bolts were torqued with readings found to be less than 20 lb-ft.

Photographs were taken and an inspection of the inner well area found only minor deformation to the sidewalls no other damage was found. The inner containment blind flange was flat and sealed with no loss of materials from within the inner containment cavity. Bolt torque of the inner flange closure ranged from 20 to 40 lb-ft. The conclusion of this series is that the design changes of increasing the blind flange thickness, increasing the torque requirement and the reinstallation of the flange inside pad were found to provide acceptable results.

2.7.8.3 Test Program #3 - Versa-Pac VP-55 Shallow Angle and Puncture Drops This program consisted of the test sequence that included a 4-foot shallow angle drop (17° from horizontal), a 30-foot shallow angle drop, and 1 meter puncture positioned with center of gravity over drum closure ring bolt [16]. This series of testing was conducted to provide additional information and verification that the VP-55 design would meet the same requirements at the previously tested VP-110 when subjected to the effects of both NCT and HAC shallow angle drops (slap down) [16].

Results of the test series showed that the outer closure was retained with no openings, tears or failure that would lead to the loss of material, no open pathway to the insulation materials and no loss of the inner containment payload. The overall diameter of the package through the impact area was reduced by 1/2 but remained the same in the opposite direction. Outer closure bolts were recorded with a post-test torque of 42 to 55 lb-ft with the bolt at the impact area at 49 lb-ft.

The outer lid was removed and no loss of containment or damage to the inner containment blind flange was found. The bolt torque of the inner blind flange was found to range between 30-50 lb-ft.

The gaskets and the internal cavity of the containment were found to be in good condition with no damage. Therefore, the VP-55 design demonstrated that it is capable of meeting the requirements set forth in 10 CFR 71 [4].

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.7.8.4 Test Program #4 - NCT Penetration and Compression Test The test article previously used in Test Program #3 was used to evaluate the performance of the Versa-Pac for the NCT penetration and stacking tests [18].

The penetration device consisted of a 1.25-inch diameter carbon steel round bar, weighing 13.2 pounds. The test article was positioned horizontally on a flat concrete floor with the penetration bar positioned vertically directly over one of three target areas: the sidewall over vertical stiffener, sidewall between vertical stiffeners and top drum lid. The bar was lifted to a height 40 inches (1 meter) and allowed to be released through a 2-inch PVC guide tube to provide the correct impact on the surface of the test package. The result of this impact to the sidewall of the test articles resulted in un-measurable damage to the package impact area and only slight marring of the package paint.

For the compression test, the test article was positioned vertically so that the load was directly applied to the top of the package. The test article weighed 624.5 pounds. To meet the requirement of 5 times the weight of the package; a load of 3,200 pounds was loaded on the top surface of the package for a period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. No damage or buckling of the package was noted upon inspection of the test article.

Review of the penetration and compression test shows that the Versa-Pac complies with the applicable regulations.

2.7.8.5 Test Program #5 - HAC 5 Pipe Container Drop Tests A new pipe container is fabricated per drawing VP-55-2R and tested without the protection provided by the Versa-Pac container. Steel shot was used to simulate the contents with sufficient ullage to induce a piston action on the pipe cap during impact [3]. Three individual test articles in three different orientations were dropped from a height of 30 feet onto an unyielding surface.

The first test article was dropped from a height of 30 feet in an oblique orientation, measured from the top of the target to the lowest point of the specimen at an angle of 15.9° from horizontal onto the bottom plate. After the drop, the damage consisted of a 1-3/16x3/16 dent to the container cap and a 1-3/8x1/16 dent to the bottom plate. The second test specimen was dropped from a height of 30 feet in the top end down position, measured from the top of the target to the lowest point on the bottom surface of the specimen. The third test specimen was dropped from a height of 30 feet in the C.G. over corner position onto the pipe cap, measured from the top of the target to the lowest point on the bottom surface of the specimen. The angle of orientation of the specimen was measured 12.5° from vertical. After the drop, there was a small dent noted on the pipe cap measuring 1-1/2x3/8 with no measurable damage on the rest of the container. After all drop tests, no release of the contents was observed. The results of the test series show that the VP-55-2R is capable of maintaining the safe geometry of the confinement vessel without failure or loss of material.

2.7.8.6 Test Program #6 - NCT and HAC Test Series at 750 lb Max Gross Weight This drop testing program was performed to increase the minimum VP-55 payload capacity to 350 lb. This program includes both NCT and HAC Free Drops and is presented in Reference [8].

The same test article was used for both the NCT and HAC test sequence. The NCT and HAC drop tests were performed in sequence. First, in an effort to loosen or dislodge the drum closure ring, the NCT 4-foot free drop was performed with the packages C.G. positioned over the drum lid closure ring bolt. Second, the package was dropped from 30 feet in the top C.G. over drum lid ring 180° from the closure bolt. Third, the dynamic crush test was performed by positioning the 2-28

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 package on the drop test pad rotated 90 degrees from the previous point of impact. Fourth, the package was subjected to the 40-inch puncture test by dropping the package top end down onto the center of the lid.

Following each test, the package was inspected with a black light and no evidence of fluorescein around the lid closure was noted. Therefore, containment of material was maintained. Mechanical damaged included localized tearing of the drum ring. However, the drum ring remained in place and no failure of the lid closure bolts occurred.

Table 2-6. Versa-Pac Test Package Dimensional Changes Maximum Description Test Program Test Series Deformation in. (cm)

NCT Inner Container ID Outer Container OD 2 3A -1/8 (-0.318)

Drum Height HAC Inner Container ID 2 3 +1/8 (+0.318)

Outer Container OD 2 3B -1 3/16 (-3.016)

Drum Height 2 1B -1/4 (-0.635)

Note: denotes no dimensional change.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.8 Accident Conditions for Air Transport of Plutonium This section is not applicable to the Versa-Pac.

2.9 Accident Conditions for Fissile Material Packages for Air Transport This section is not applicable to the Versa-Pac. The criticality analysis for Versa-Pac packages transported by air assumes ejection of all contents from the packaging into a bounding configuration (See Section 6.7). Thus, no structural testing/analyses are necessary for Versa-Pac shipments via air transport.

2.10 Special Form Special form material as defined in 10 CFR 71 is not applicable to the Versa-Pac.

2.11 Fuel Rods This section is not applicable to the Versa-Pac.

2.12 Appendices 2.12.1 References .......................................................................................................................................................... 2-31 2.12.2 VP-55 LS-DYNA analysis .............................................................................................................................. 2-33 2.12.3 High-Capacity Basket Stress Analysis.....................................................................................................2-71 2-30

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.1 References

[1] American National Standards Institute, "Uranium Hexafluoride - Packagings for Transport," ANSI N14.1.

[2] United States Department of Transportation (USDOT), "Code of Federal Regulations, Title 49:

Transportation," § 178.360, Washington, D.C., 2004.

[3] Daher-TLI, "5-Inch Container Drop Test Report," TR-20000-050-102, Rev. 0, Fulton, MD, 2015.

[4] Nuclear Regulatory Commission (NRC), "Title 10, Part 71-Packaging and Transportation of Radioactive Material".

[5] Nuclear Regulatory Commission (NRC), "Title 10, Part 71-Packaging and Transportation of Radioactive Material, Subpart H - Quality Assurance".

[6] American Welding Society (AWS), "D1.1/D1.1M:2010, Structural Welding Code - Steel".

[7] The American Society for Nondestructive Testing, Inc., "Recommended Practice No. SNT-TC-1A Personnel Qualification and Certification in Nondestructive Testing," 2006.

[8] Daher-TLI, "55 Gallon Versa-Pac Drop Test Deformation Measurement Report," TR-20000-100-001, Fulton, MD, 2017.

[9] International Atomic Energy Agency (IAEA), "Regulations for the Safe Transport of Radioactive Material, SSR-6, 2012 Edition".

[10] Daher-TLI, "Quality Assurance Program Description," QAPD1, Rev. 3, 2020.

[11] MACTEC Engineering & Consulting, Inc., "Corrosion of Carbon and Stainless Steel in Contact with Foam," Project 6230-03-0989, Charlotte, NC, 2004.

[12] R. B. Ross, Metallic Materials Specification Handbook, 4th Edition, London: Chapman and Hall, 1992.

[13] General Plastics, "Design Guide LAST-A-FOAM FR-3700 Crash & Fire Protection of Radioactive Material Shipping Containers".

[14] The American Society of Mechanical Engineers (ASME), "Boiler and Pressure Vessel Code, BPVC-IX -- Section IX, Welding and Brazing Qualifications," 2015.

[15] Century Industries, "Test Report Performance Test Series of Century Industries Model VP-55 & VP-110 Versa-Pac Shipping Container," Bristol, VA, 2009.

[16] Century Industries, "Test Report Performance Evaluation Test Series of Century Industries Model VP-55 Versa-Pac Shipping Container," Bristol, VA, 2009.

[17] Daher-TLI, "Century Champion Type B Package Immersion Test as Analogue for the Versa-Pac Type A Package," TR-20000-130-001, Rev. 0, Fulton, MD, 2021.

[18] Century Industries, "NCT Evaluation Test Series (Compression & Penetration) of Century Industries Versa-Pac Shipping Container," Bristol, VA, 2009.

[19] United States Department of Transportation (USDOT), "Title 49, Code of Federal Regulations Part 178, Specifications for Packagings, Subpart MTesting of Non-bulk Packagings and Packages".

[20] Nuclear Regulatory Commission Office of Nuclear Material Safety and Safeguards, "Drop Test Results for the Combustion Engineering Model No. ABB-2901 Fuel Pellet Shipping Package,"

NUREG/CR-6818, Washington, D.C., 2003.

[21] Savannah River Site (SRS), "Drop Test for the 6M Specification Closure Investigation," M-TRT-A-00002 Rev. 0, Aiken, SC, 2003.

[22] P. John F. Harvey, Theory and Design of Pressure Vessels, Second Edition, New York: Van Nostrand Reinhold, 1991.

[23] Livermore Software Technology Corporation, "LS-DYNA, A Program for Nonlinear Dynamic Analysis of Structures in Three Dimensions," Version: mpp s R10.1.0, Revision: 123264, Date: 01/12/2018.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021

[24] ANSYS, Inc., "Mechanical APDL," Release 2020 R2, Build 20.2 UP20200601, Windows x64 Platform.

[25] R. A. Bailey, "STRAIN 2.0 Database," 1988.

[26] Azo Materials, "E-Glass Fibre," [Online]. Available:

https://www.azom.com/properties.aspx?ArticleID=764. [Accessed 22 November 2021].

[27] General Plastics, "Last-a-Foam FR-3705 Rigid Polyurethane Foam," 2015.

[28] AZO Materials, "Silicone Rubber," [Online]. Available: https://www.

azom.com/properties.aspx?ArticleID=920. [Accessed 22 November 2021].

[29] Portland Bolt, "SAE J429," [Online]. Available: portlandbolt.com/technical/specification/sae-j429/.

[Accessed 22 November 2021].

[30] American Society of Mechanical Engineers (ASME), "Boiler and Pressure Vessel Code - Rules for Construction of Nuclear Power Plant Components,"Section III, Division I, Subsection NF, Supports, 2010 Edition With Addenda.

[31] ANSYS, "Workbench," Version 19.1, Canonsburg, PA, 2018.

[32] American Society of Mechanical Engineers (ASME), "Boiler and Pressure Vessel Code (BPVC),

Section II Part D, Properties (Customary)," 2010 .

[33] CORZAN Industries, "Piping Systems, Basic Physical Proprerties," 2002

[34] American Society of Mechanical Engineers(ASME), "Boiler and Pressure Vessel Code - Rules for Construction of Nuclear Facility Components,"Section III, Division I - Appendices.

[35] E. Oberg, F. D. Jones, H. L. Horton and H. H. Ryffel, Machinery's Handbook, 26 ed., New York:

Industrial Press, 2000.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2 VP-55 LS-DYNA analysis This appendix summarizes the results of LS-DYNA [23] impact analyses for the Versa-Pac 55 (VP-55) shipping container during the normal conditions of transport (NCT) and hypothetical accident conditions (HAC) prescribed by 10 CFR 71 [4]. Specifically, the VP-55with a total weight of 750 lb (340 kg) including contentsis analyzed for the conditions presented in Table 2-7. The acceleration results calculated in this appendix are used to evaluate contents support structures.

Table 2-7. Summary of Conditions Analyzed Conditions Test Description CFR Section Free dropFree drop of the package from a height of 4 ft onto a flat, NCT 10 CFR 71.71(7) unyielding, horizontal surface.

Free dropFree drop of the package from a height of 30 ft onto a flat, HAC 10 CFR 71.73(c)(1) unyielding, horizontal surface.

2.12.2.1 Summary of Results The calculated peak accelerations presented in this appendix for the VP-55 Package contents during NCT and HAC free drop conditions are summarized in Table 2-8 and Table 2-9, respectively.

Table 2-8. NCT 4-ft Free Drop VP-55 Package Contents Peak Acceleration Package Orientation/Impact Peak Rigid-Body Acceleration (g)

Location Hot/Soft Foam Properties Cold/Hard Foam Properties Bottom-End 104 105 Top-End 43 111 Side 105 121 C.G. over Top-Corner 92 133 Table 2-9. HAC 30-ft Free Drop VP-55 Package Contents Peak Acceleration Package Orientation/Impact Peak Rigid-Body Acceleration (g)

Location Hot/Soft Foam Properties Cold/Hard Foam Properties Bottom-End 381 394 Top-End 355 208 Side 403 515 C.G. over Top-Corner 422 352 2-33

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.2 Method of Analysis The LS-DYNA [23] explicit nonlinear dynamics code is used to determine the dynamic response of the VP-55 shipping container to the NCT free drop and HAC free drop tests specified in 10 CFR 71. A three-dimensional, full-symmetry model of the VP-55loaded with mock contents that represent the weight of the actual contentsis generated using the ANSYS Parametric Design Language (APDL) [24]. Prior to executing the controlling ANSYS macro to generate the model, a parameter file is modified to specify the package orientation and the position of the contents relative to the Inner Container cavity. The APDL model generation outputs text files containing the three-dimensional model and boundary conditions.

The model generated by APDL is then used to perform the LS-DYNA analyses simulating the NCT and HAC free drops. For the NCT and HAC free drops, four package orientations are evaluatedbottom-end, top-end, side, and c.g. over top-corneras shown in Figure 2-1. A drop with the c.g. over the bottom corner is bounded by the bottom-end and side drop orientations and is therefore not evaluated.

When simulating the free drop of the VP-55 Package, the package is modeled in one of the orientations shown in Figure 2-1 with it almost (within 0.001 in.) touching the modeled flat, unyielding, horizontal surface with an initial velocity applied to simulate the drop from the height for the conditions being evaluated.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-1. Free Drop Orientations Evaluated for NCT and HAC 2-35

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.3 Finite Element Model Description The VP-55 three-dimensional finite element modelpresented in Figure 2-2consists of 74 separate parts that are constructed using solid elements with reduced integration constant stress formulation (ELFORM = 1), solid elements with fully integrated formulation (ELFORM = 2), and shell elements with Hughes-Liu formulation (ELFORM = 1). Use of the fully integrated solid elements (ELFORM = 2) are limited to those parts that require a significant amount of hourglass energy (more that 10% of the internal energy) for the part to prevent significant hourglassing or would result in negative volumes due to significant deformation. The model is generated using the ANSYS Parametric Design Language (APDL) [24] and exported as a text file that is read by the controlling LS-DYNA input file during the solution process.

In addition to the 74 parts that make up the VP-55 package, the finite element model also includes parts that represent the contents and the horizontal unyielding horizontal surface or ground. The contents are represented as a right-circular cylinder (diameter = 14 in., height = 22.125 in.)

weighing 348.7 lb. The modeled contents have a diametrical clearance of 1 in. and an axial clearance of 1 in. with the Inner Container payload cavity. The contents are modeled as A36 steel with a density of 0.1026 lb/in³.

The 78 parts that make up the LS-DYNA model are listed in Table 2-10. The element type and formulation (ELFORM), hourglass ID (HGID), and the material ID assigned to each part are listed in this table. Figure 2-3 shows an exploded view of the model with part IDs. Material properties are discussed in Section 2.12.2.4 and listed in Table 2-11.

Figure 2-2. Three-Dimensional Finite Element Model of the VP-55 2-36

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 2-10. VP-55 Finite Element Model Parts Drawing LS-Dyna Element Type VP-55-LD Description HGID Material ID Part ID / ELFORM Item No. #

1 52 Vertical Stiffeners Solid / 1 1 1 2 12 Inner Stiffening Flange Solid / 1 1 1 3 47 Center Stiffening Ring Web Solid / 1 1 1 4 -- Weld, 3/16, 2-4, Part [3] to Part [2] Solid / 1 1 2 5 -- Weld, 3/16, Part [3] to Part [1] Solid / 1 1 2 6 44 Bottom Plate Ring Solid / 1 1 1 7 --- Weld, 3/16, Part [6] to Part [1] Solid / 1 1 2 8 --- Weld, 3/16, Part [6] to Part [2] Solid / 1 1 2 9 --- Weld, 1/16, Part [2] to Part [28] Shell / 1 2 2 10 43 Bottom Reinforcing Plate Solid / 1 1 1 11 13 Top Stiffening Ring Solid / 1 1 1 12 --- Weld, 3/16, Part [2] to Part [1] Solid / 1 1 2 13 --- Weld, 3/16, Part [2] to Part [1] Solid / 1 1 2 14 --- Weld, 3/16, Part [2] to Part [1] Solid / 1 1 2 15 --- Weld, 1/16, Part [11] to Part [28] Shell / 1 2 2 16 5 Retaining Ring Solid / 1 1 1 17 --- Weld, 3/16, Part [5] to Part [11] Solid / 1 1 2 18 --- Weld, 3/16, Part [1] to Part [11] Solid / 1 1 2 19 --- Weld, 3/16, Part [1] to Part [11] Solid / 1 1 2 20 --- Weld, 3/16, Part [1] to Part [11] Solid / 1 1 2 21 --- Weld, Part [23] to Part [1] Solid / 1 1 2 22 --- Weld, 1/8, Part [24] to Part [11] Solid / 1 1 2 23 16 Threaded Insert Solid / 1 1 1 24 45 Top Plate Ring Solid / 1 1 1 25 --- Weld, 3/16, Part [1] to Part [24] Solid / 1 1 2 26 --- Weld, 3/16, Part [23] to Part [24] Solid / 1 1 2 27 15 Reinforcing Backing Bar Solid / 1 1 2 28 49 Inner Liner Shell / 1 2 1 29 14 Outer Stiffening Reinforcing Sheet Shell / 1 2 1 30 --- Weld, 1/16, Part [2] to Part [28] Shell / 1 2 2 31 14 Outer Stiffening Reinforcing Sheet at Weld to Part [6] Solid / 1 1 1 32 --- Weld, Part [10] to Part [6] & Part [27] Solid / 1 1 2 33 36 Fiberglass Spacer Solid / 2 N/A 4 34 35 Fiberglass Ring Solid / 2 N/A 4 35 27 Drum Lid Inner Gasket Solid / 1 1 5 36 32 Plug Insulator - Bottom Body Solid / 1 3 6 37 46 Inner Flange Ring Solid / 1 1 1 38 --- Weld, 3/16, Part [40] to Part [41] Solid / 1 1 2 39 22 Connection Ring Solid / 1 1 1 40 16 Threaded Insert Solid / 1 1 1 41 39 Containment Body Solid / 1 1 1 42 --- Weld, Part [40] to Part [37] Solid / 1 1 2 43 --- Weld, 1/8, Part [40] to Part [41] Solid / 1 1 2 44 8 Containment Plug Retaining Bar Solid / 1 1 1 45 --- Weld, 1/8, Part [45] to Part [41] Solid / 1 1 2 46 --- Weld, 1/8, Part [47] to Part [41] Solid / 1 1 2 47 40 Containment End Plate Solid / 1 1 1 48 28 Containment Gasket Solid / 1 1 5 49 31 Ceramic Blanket Solid / 2 N/A 7 50 37 Containment Insulation Plug Solid / 1 3 6 2-37

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Drawing LS-Dyna Element Type VP-55-LD Description HGID Material ID Part ID / ELFORM Item No. #

51 42 Blind Flange Solid / 1 1 1 52 41 Drum Lid Reinforcing Ring Solid / 1 1 8 53 10 Drum Lid Shell / 1 2 1 54 --- Weld, 1/16 Shell / 1 2 2 55 --- Weld, 1/16 Shell / 1 2 2 56 --- Weld, Seal Shell / 1 2 2 57 --- Weld, Seal Shell / 1 2 2 58 33 Plug Insulator-Drum Lid Solid / 1 3 6 59 50 Top Plug Wall Shell / 1 2 1 60 51 Top Plug Cap Shell / 1 2 1 61 18 Hex Head Bolt, 1/2-13 UNC 2A x 1-1/4 LG Solid / 1 1 11 62 24 Hex Nut, 1/2-UNC Solid / 1 1 1 63 18 Hex Head Bolt, 1/2-13 UNC 2A x 1-1/4 LG Solid / 1 1 12 64 19 Lock Washer, 1/8 x 9/16 Dia. Solid / 1 1 12 65 25 Hex Head Bolt, 1/2-13 UNC 2A x 1-1/2 LG Solid / 1 1 11 66 19 Lock Washer, 1/8 x 9/16 Dia. Solid / 1 1 12 67 23 Flat Washer, 9/16 Dia. Solid / 1 1 12 68 9 Drum, 55-Gallon, Body Shell / 1 2 8 69 9 Drum, 55-Gallon, Bottom Shell / 1 2 8 70 11 Drum Ring Shell / 1 2 8 71 --- Drum Ring Lug Solid / 1 1 8 72 --- Drum Ring Bolt Solid / 1 1 9 73 --- Drum Ring Nut Solid / 1 1 10 74 --- Weld, 1/16, Part [24] to Part [68] Shell / 1 2 2 75 --- Mock Contents Solid / 1 3 13 76 --- Ground (Rigid) Shell / 1 2 14 2-38

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-3. Exploded View of Versa-Pac 55 Finite Element Model 2-39

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.4 Material Properties Table 2-11 presents the material model used for each material in the model, and the bolt material is the only material to include element erosion when its strain limit is reached.

Table 2-11. Material IDs and Material Models Incorporated in the LS-DYNA Analysis Material Element Description Material Material Model ID Erosion Inner Container &

1 Internal Structural Support 2 Welds Carbon Steel Plate, A36 *MAT_POWER_LAW_PLASTICITY No 8 Drum 10 Drum Clamp Nut 12 Nuts & Washers 4 Spacer & Ring Fiberglass *MAT_ELASTIC N/A Inner Container &

5 Silicone Rubber *MAT_ELASTIC N/A Drum Lid Gaskets 6 Insulation Plugs 5 PCF Polyurethane Foam *MAT_CRUSHABLE_FOAM No Inner Container 7 Ceramic Blanket *MAT_CRUSHABLE_FOAM No Wrap 9 Drum Clamp Bolt Steel Allenoy Allen Socket Blind Flange Bolts & Cap Screw *MAT_POWER_LAW_PLASTICITY Yes 11 0 to 0.5-in. Diameter Drum Lid Bolts Steel A36 with Custom 13 Mock Contents *MAT_POWER_LAW_PLASTICITY No Density 14 Ground Rigid *MAT_RIGID N/A 2.12.2.4.1 Carbon Steel A36 The Inner Container, Internal Structural Support and Drum Lid are constructed of carbon steel A36. In the analyses presented in this calculation note, the A36 steel is modeled as having elastoplastic behavior with isotropic hardening using the *MAT_POWER_LAW_PLASTICITY material model in LS-DYNA. For this material model, the stress () strain () relationship is defined through the strain-hardening equation:

= "

where, = strength coefficient, and

= hardening exponent (i.e., plastic strain).

The properties used for the Carbon Steel A36 material are obtained from the STRAIN 2.0 database [25]. Specifically, the properties for steel carbon A36 plate are used and are presented in Table 2-12. Additionally, the strain-hardening of the carbon steel A36 is presented graphically in Figure 2-4.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 2-12. Carbon Steel A36 Material Properties True Yield Strength Modulus of Density Poissons Plastic Elongation Strength, ! Coefficient, Elasticity (psi) (lbm/in3) Ratio Strain, at Failure (psi) (psi) 30 x 10 0.283 0.29 28,087 117,180 0.20483 23%

Figure 2-4. Carbon Steel A36 Strain-Hardening Stress-Strain Curve 2.12.2.4.2 Fiberglass Spacers Fiberglass spacer and ring are incorporated in the VP-55 design between certain steel components to limit the transfer of heat via thermal conduction. Specifically, a fiberglass spacer separates the Inner Container from the Internal Structural Support, and a fiberglass ring separates the Inner Container Blind Flange from the Internal Structural Support. The fiberglass spacer and ring are modeled using the elastic properties of E-Glass Fibre [26] presented in Table 2-13.

Table 2-13. E-Glass Fibre Material Properties Modulus of Elasticity (psi) Density (lbm/in3) Poissons Ratio 12.328 x 106 0.094 0.23 2-41

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.4.3 5 PCF Polyurethane Foam The VP-55 design incorporates several polyurethane foam plugs for impact-limiting and thermal insulation. The Plug Insulator-Bottom Body is approximately 2.75-in. thick and separates the Containment End Plate from the Bottom Reinforcing Plate. The Plug Insulator-Drum Lid is approximately 2.31-in. thick. And the Containment Insulation Plugsituated in the Inner Container cavityis 3.00-in. thick. These plugs are made from 5 PCF (pound per cubic foot) polyurethane foam. Its stress-strain data is obtained from reference [27], and is dependent on the temperature of the foam. The stress-strain data for the hot/soft (180°F) and cold/hard (-40°F) is presented in tabular form in Table 2-14 and graphically in Figure 2-5.

Table 2-14. 5 PCF Polyurethane Foam Stress-Strain Data Stress (psi)

Strain Hot/Soft (180°F) Cold/Hard (-40°F) 0.00 0 0 0.05 55 191 0.10 75 265 0.20 79 269 0.30 81 261 0.40 81 255 0.50 87 262 0.60 104 310 0.70 140 416 0.80 336 970 Figure 2-5. 5 PCF Polyurethane Foam Stress-Strain Curves 2-42

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.4.4 Silicone Rubber Gaskets Silicone rubber gaskets are used between mating surfaces of the bolted closures of the VP-55 design. Specifically, there is 1/8-in. thick gasket between the Inner Container Blind Flange and Inner Flange Ring, and there is a 0.308-in. thick gasket between the Drum Lid and Top Plate Ring of the Internal Structural Support. Although a gasket may be used between the Drum top ring and Clamp Ring, no gasket is included in the model for this connection. The elastic material properties of silicone rubber [28] are presented in Table 2-15.

Table 2-15. Silicone Rubber Material Properties (Min/Max Values)

Modulus of Elasticity (psi) Density (lbm/in3) Poissons Ratio 2 3 1.45 x 10 / 7.25 x 10 0.0397 / 0.083 0.47 / 0.49 2.12.2.4.5 Bolts The bolts used to connect various components in the VP-55 Package are specified as ASTM A429/SAE J429 Grade 5 minimum. SAE J429 Grade 5 bolts have a minimum tensile strength of 12,000 psi and a minimum elongation of 14% per reference [29].

2.12.2.4.6 Ceramic Blanket The ceramic blanket wrap around the Inner Container is modeled with the material properties of 5 PCF polyurethane foam. Basis: Dynamic material properties for the ceramic blanket are unavailable in the open literature. Additionally, the ceramic blanket has a density of 6 to 8 PCF which is comparable to the polyurethane foam. The polyurethane foam is a very soft material which allows for a large compression of the blanket.

2.12.2.5 Boundary Conditions, Loads, and Initial Conditions To simulate the free-drop the VP-55 package, a constant acceleration of 32.17 ft/s² (386.04 in/s²)

is applied to all parts of the model. The nodes of the shell elements representing the flat, horizontal, unyielding surface are constrained in all three translational directions and all three rotational directions.

The free drop of the VP-55 package is governed by the equations for uniformly accelerated rectilinear motion:

K = K 1 !

(  % ! ) = ( & )

2

! = & ! + 2( & )

where, = velocity, t = time, and g = gravitational constant.

v' = initial velocity, and h& = initial height 2-43

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 At the beginning of the free drop, the velocity of the package is zero (& = 0), and the initial height (with respect to the starting location) is zero (& = 0). This results in the following equation for the velocity of the package when falling from a height, , of:

= ^2 Using this equation, the initial velocities applied to the LS-DYNA model are summarized in Table 2-16.

Table 2-16. Velocity used in the LS-DYNA Analyses Conditions Item Drop Height Velocity at Impact NCT Free Drop VP-55 Package 4 ft 192.51 in/s HAC Free Drop VP-55 Package 30 ft 527.21 in/s Bolts used to connect various parts in the VP-55 finite element model is modeled with solid elements and has an effective diameter based on its tensile stress area. The interaction of the bolt threads with the base material threads is simulated by merging the nodes of the bolt with the base material. The bolts are preloaded based on the torque specified Table 2-17 in a dynamic relaxation step in LS-DYNA prior to initiation of the free drop analyses using the

• INITIAL_STRESS_SECTION keyword.

Table 2-17. Bolt Sizes, Specification, and Preload Torque Preload Connection Bolt Size Specification Torque Blind Flange-to-Inner Hex Head, 1/2-13 UNC 2A, ASTM A429/SAE J429, Gr 5 60 ft-lb Container 1.25-in. long Min.

Inner Container-to-Internal Hex Head, 1/2-13 UNC 2A, ASTM A429/SAE J429, Gr 5 20 ft-lb Structural Support 1.25-in. long Min.

Drum Lid/Top Plug-to- Hex Head, 1/2-13 UNC 2A, ASTM A429/SAE J429, Gr 5 60 ft-lb Internal Structural Support 1.5-in. long Min.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.6 NCT Free Drop Results LS-DYNA simulations are performed for the NCT 4-ft free drop using the finite element model and analysis procedures described in Section 2.12.2.3. The NCT 4-ft free drop of the package onto a flat, horizontal, unyielding surface is simulated using both hot/soft and cold/hard properties for the polyurethane foam/ceramic blanket wrap. The NCT 4-ft free drop is simulated with LS-DYNA by positioning the VP-55 Package model in the desired orientation within 0.001 in. of the shell elements representing the flat unyielding surface, and an initial velocity of -192.51 in/s is applied in the z-direction. The gravitational constant of 386.04 in/s² is applied to the model as a body load using the *LOAD_BODY_Z keyword. Additionally, the degree-of-freedom of each node for the shell elements representing the ground is fixed in all translational and rotational directions. The NCT 4-ft free drop results (content peak acceleration and displacement) are summarized in Table 2-18.

The results of the Cold/Hard foam property cases, which produces the highest accelerations, are presented in Section 2.12.2.6.1 through Section 2.12.2.6.4.

Table 2-18. NCT Free Drop Results Summary Foam/Ceramic Blanket Contents Peak Displacement Drop Orientation Properties Acceleration (g) Part Value Containment End Hot/Soft 104 UZ = -0.61 in.

Plate (#47)

Bottom-End Containment End Cold/Hard 105 UZ = -0.54 in.

Plate (#47)

Hot/Soft 43 Blind Flange (#51) UZ = -0.43 in.

Top-End Cold/Hard 111 Blind Flange (#51) UZ = -0.45 in.

Containment Body Hot/Soft 105 UZ = -2.33 in.

(#41)

Side Containment Body Cold/Hard 121 UZ = -2.11 in.

(#41)

UX = +0.09 in.

Hot/Soft 92 Blind Flange (#51)

UZ = -0.89 in.

Top-Corner UX = +0.14 in.

Cold/Hard 133 Blind Flange (#51)

UZ = -0.92 in.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.6.1 NCT Bottom-End 4-ft Free Drop with Cold/Hard Foam Properties The NCT bottom-end free drop of the VP-55 is evaluated using the LS-DYNA model described in Section 2.12.2.3. This case assumes that the package is dropped in a vertical orientation onto the bottom-end of the package from a height of 4 ft. This is accomplished by positioning the VP-55 package bottom in contact with the unyielding horizontal surface (represented with rigid shell elements) and applying an initial velocity of 192.51 in/s in the downward direction. Additionally, a gravitational acceleration of 386.04 in/s² is applied to the model. The time-histories results are filtered using the Butterworth filter at a frequency of 100 Hz.

Figure 2-6 shows a cut-view of the model deformation when the kinetic energy reaches its minimum value at 0.011 seconds of the simulation. Figure 2-7 shows the deflection of the inner container containment end plate (maximum deflection = -0.54 in.) time-history. The foam plug compresses to a thickness of 2.67 in. from an initial thickness of 2.75 in. resulting in 3%

compression of the foam (1.00 - 2.67/2.75 = 3%). Figure 2-8 shows the rigid-body acceleration time-history of the contents of the Inner Container. The contents reach a peak rigid-body acceleration of 105 g. The energy balance time-history is shown in Figure 2-9. The results show that the initial kinetic energy is converted into strain energy (internal energy) and contact friction energy (sliding energy) due to crushing of the polyurethane foam and contact of the various components. The hourglass energy is low, indicating that the strain energy used to control the hourglass distortion of the models brick elements is acceptably low (less than 10% of the internal energy). The sliding energy remains positive throughout the impact simulation, indicating proper behavior of the modeled contact interfaces.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-6. NCT Bottom-End 4-ft Free Drop with Cold/Hard Foam Properties Deformation at t = 0.011 s Figure 2-7. NCT Bottom-End 4-ft Free Drop with Cold/Hard Foam PropertiesInner Container Containment End Plate Deflection (at Center) 2-47

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-8. NCT Bottom-End 4-ft Free Drop with Cold/Hard Foam PropertiesContents Rigid-Body Z-Acceleration Figure 2-9. NCT Bottom-End 4-ft Free Drop with Cold/Hard Foam PropertiesEnergy Time-Histories 2-48

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.6.2 NCT Top-End 4-ft Free Drop with Cold/Hard Foam Properties The NCT top-end free drop of the VP-55 is evaluated using the LS-DYNA model described in Section 2.12.2.3. This case assumes that the package is dropped in a vertical orientation onto the bottom-end of the package from a height of 4 ft. This is accomplished by positioning the VP-55 package bottom in contact with the unyielding horizontal surface (represented with rigid shell elements) and applying an initial velocity of 192.51 in/s in the downward direction. Additionally, a gravitational acceleration of 386.04 in/s² is applied to the model. The time-histories results are filtered using the Butterworth filter at a frequency of 250 Hz.

Figure 2-10 shows a cut-view of the model deformation when the kinetic energy reaches its minimum value at 0.036 seconds of the simulation. Figure 2-11 shows the deflection of the inner container containment end plate (maximum deflection = -0.45 in.) time-history. The Containment Insulation Plug compresses to a thickness of 2.57 in. from an initial thickness of 3.00 in. resulting in 14% compression of the foam (1.00 - 2.57/3.00 = 14%). The Plug Insulator-Drum Lid compresses to a thickness of 2.29 in. from an initial thickness of 2.31 in. resulting in 1%

compression of the foam (1.00 - 2.29/2.31 = 1%). Figure 2-12 shows the rigid-body acceleration time-history of the contents of the Inner Container. The contents reach a peak rigid-body acceleration of 105 g. The energy balance time-history is shown in Figure 2-13. The results show that the initial kinetic energy is converted into strain energy (internal energy) and contact friction energy (sliding energy) due to crushing of the polyurethane foam and contact of the various components. The hourglass energy is low, indicating that the strain energy used to control the hourglass distortion of the models brick elements is acceptably low (less than 10% of the internal energy). The sliding energy remains positive throughout the impact simulation, indicating proper behavior of the modeled contact interfaces.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-10. NCT Top-End 4-ft Free Drop with Cold/Hard Foam PropertiesDeformation at t = 0.0136 s Figure 2-11. NCT Top-End 4-ft Free Drop with Cold/Hard Foam PropertiesInner Container Blind Flange Deflection (at Center) 2-50

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-12. NCT Top-End 4-ft Free Drop with Cold/Hard Foam PropertiesContents Rigid-Body Z-Acceleration Figure 2-13. NCT Top-End 4-ft Free Drop with Cold/Hard Foam PropertiesEnergy Time-Histories 2-51

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.6.3 NCT Side 4-ft Free Drop with Cold/Hard Foam Properties The NCT side free drop of the VP-55 is evaluated using the LS-DYNA model described in Section 2.12.2.3. This case assumes that the package is dropped in a horizontal orientation onto the side of the package (drum clamp ring lug impacting first) from a height of 4 ft. This is accomplished by positioning the VP-55 package on its side with the drum clamp ring lug in contact with the unyielding horizontal surface (represented with rigid shell elements) and applying an initial velocity of 192.51 in/s in the downward direction. Additionally, a gravitational acceleration of 386.04 in/s² is applied to the model. The time-histories results are filtered using the Butterworth filter at a frequency of 400 Hz.

Figure 2-14 shows a cut-view of the model deformation when the kinetic energy reaches its minimum value at 0.016 seconds of the simulation. Figure 2-15 shows the deflection of the Inner Containment Body (maximum deflection = -2.11 in. near the bottom of the Containment Body) time-history. The Ceramic Blanket compresses to a thickness of 1.58 in. from an initial thickness of 1.98 in. resulting in 20% compression of the blanket (1.00 - 1.58/1.98 = 20%). Figure 2-16 shows the rigid-body acceleration time-history of the contents of the Inner Container. The contents reach a peak rigid-body acceleration of 121 g. The energy balance time-history is shown in Figure 2-17. The results show that the initial kinetic energy is converted into strain energy (internal energy) and contact friction energy (sliding energy) due to crushing of the polyurethane foam and contact of the various components. The hourglass energy is low, indicating that the strain energy used to control the hourglass distortion of the models brick elements is acceptably low (less than 10% of the internal energy). The sliding energy remains positive throughout the impact simulation, indicating proper behavior of the modeled contact interfaces.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-14. NCT Side 4-ft Free Drop with Cold/Hard Foam PropertiesDeformation at t = 0.016 s Figure 2-15. NCT Side 4-ft Free Drop with Cold/Hard Foam Properties Containment Body Deflection (at Bottom) 2-53

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-16. NCT Side 4-ft Free Drop with Cold/Hard Foam PropertiesContents Rigid-Body Z-Acceleration Figure 2-17. NCT Side 4-ft Free Drop with Cold/Hard Foam PropertiesEnergy Time-Histories 2-54

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.6.4 NCT Top-Corner 4-ft Free Drop with Cold/Hard Foam Properties The NCT top-corner free drop of the VP-55 is evaluated using the LS-DYNA model described in Section 2.12.2.3. This case assumes that the package is dropped in a vertical orientation onto the bottom-end of the package from a height of 4 ft. This is accomplished by positioning the VP-55 package bottom in contact with the unyielding horizontal surface (represented with rigid shell elements) and applying an initial velocity of 192.51 in/s in the downward direction. Additionally, a gravitational acceleration of 386.04 in/s² is applied to the model. The time-histories results are filtered using the Butterworth filter at a frequency of 400 Hz.

Figure 2-18 shows a cut-view of the model deformation when the kinetic energy reaches its minimum value at 0.018 seconds of the simulation. Figure 2-19 shows the deflection of the Inner Container Blind Flange (maximum x-deflection = +0.14 in. and z-deflection = -0.92 in. near the corner that impacts). The Containment Insulation Plug compresses to a thickness of 2.61 in. from an initial thickness of 3.00 in. resulting in 13% compression of the foam (1.00 - 2.61/3.00 = 13%).

The Insulator Plug-Drum Lid compresses to a thickness of 2.30 in. from an original thickness of 2.31 in. resulting in 0% of the foam (1.00 - 2.30/2.31 = 0%). The Ceramic Blanket compresses to a thickness of 1.87 in. from an initial thickness of 1.98 in. resulting in 5% compression of the blanket (1.00 - 1.87/1.98 = 5%). Figure 2-20 shows the rigid-body acceleration time-history of the contents of the Inner Container. The contents reach a peak rigid-body acceleration of 133 g.

The energy balance time-history is shown in Figure 2-21. The results show that the initial kinetic energy is converted into strain energy (internal energy) and contact friction energy (sliding energy) due to crushing of the polyurethane foam and contact of the various components. The hourglass energy is low, indicating that the strain energy used to control the hourglass distortion of the models brick elements is acceptably low (less than 10% of the internal energy). The sliding energy remains positive throughout the impact simulation, indicating proper behavior of the modeled contact interfaces.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-18. NCT Top-Corner 4-ft Free Drop with Cold/Hard Foam Properties Deformation at t = 0.018 s Figure 2-19. NCT Top-Corner 4-ft Free Drop with Cold/Hard Foam Properties Containment Body Deflection (at Bottom) 2-56

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-20. NCT Top Corner 4-ft Free Drop with Cold/Hard Foam PropertiesContents Rigid-Body Z-Acceleration Figure 2-21. NCT Top-Corner 4-ft Free Drop with Cold/Hard Foam PropertiesEnergy Time-Histories 2-57

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.7 HAC Free Drop Results LS-DYNA simulations are performed for the HAC 30-ft free drop using the finite element model described in Section 2.12.2.3. The HAC 30-ft free drop of the package onto a flat, horizontal, unyielding surface is simulated using both hot/soft and cold/hard properties for the polyurethane foam/ceramic blanket wrap. The HAC 30-ft free drop is simulated with LS-DYNA by positioning the VP-55 Package model in the desired orientation within 0.001 in. of the shell elements representing the flat unyielding surface, and an initial velocity of 527.21 in/s is applied in the z direction. The gravitational constant of 386.04 in/s² is applied to the model as a body load using the *LOAD_BODY_Z keyword. Additionally, the degree-of-freedom of each node for the shell elements representing the ground is fixed in all translational and rotational directions. The HAC 30-ft free drop results (content peak acceleration and displacement) are summarized in Table 2-19.

The results of the foam property case that produce the highest accelerations for each drop orientation are presented in Section 2.12.2.7.1 through Section 2.12.2.7.4.

Table 2-19. HAC Free Drop Results Summary Foam/Ceramic Blanket Contents Peak Displacement Drop Orientation Properties Acceleration (g) Part Value Containment End Hot/Soft 381 UZ = -1.72 in.

Plate (#47)

Bottom-End Containment End Cold/Hard 394 UZ = -1.52 in.

Plate (#47)

Hot/Soft 355 Blind Flange (#51) UZ = -1.60 in.

Top-End Cold/Hard 208 Blind Flange (#51) UZ = -1.37 in.

Containment Body Hot/Soft 403 UZ = -3.82 in.

(#41)

Side Containment Body Cold/Hard 515 UZ = -3.36 in.

(#41)

UX = +0.12 in.

Hot/Soft 422 Blind Flange (#51)

UZ = -1.96 in.

Top-Corner UX = +0.30 in.

Cold/Hard 352 Blind Flange (#51)

UZ = -2.15 in.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.7.1 HAC Bottom-End 30-ft Free Drop with Cold/Hard Foam Properties The HAC bottom-end free drop of the VP-55 is evaluated using the LS-DYNA model described in Section 2.12.2.3 This case assumes that the package is dropped in a vertical orientation onto the bottom-end of the package from a height of 30 ft. This is accomplished by positioning the VP-55 package bottom in contact with the unyielding horizontal surface (represented with rigid shell elements) and applying an initial velocity of 527.21 in/s in the downward direction. Additionally, a gravitational acceleration of 386.04 in/s² is applied to the model. The time-histories results are filtered using the Butterworth filter at a frequency of 100 Hz.

Figure 2-22 shows a cut-view of the model deformation when the kinetic energy reaches its minimum value at 0.0062 seconds of the simulation. Figure 2-23 shows the deflection of the inner container containment end plate (maximum deflection = -1.52 in.) time-history. The foam plug compresses to a thickness of 1.98 in. from an initial thickness of 2.75 in. resulting in 28%

compression of the foam (1.00 - 1.98/2.75 = 28%). Figure 2-24 shows the rigid-body acceleration time-history of the contents of the Inner Container. The contents reach a peak rigid-body acceleration of 394g. The energy balance time-history is shown in Figure 2-25. The results show that the initial kinetic energy is converted into strain energy (internal energy) and contact friction energy (sliding energy) due to crushing of the polyurethane foam and contact of the various components. The hourglass energy is low, indicating that the strain energy used to control the hourglass distortion of the models brick elements is acceptably low (less than 10% of the internal energy). The sliding energy remains positive throughout the impact simulation, indicating proper behavior of the modeled contact interfaces.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-22. HAC Bottom-End 30-ft Free Drop with Cold/Hard Foam Properties Deformation at t = 0.0062 s Figure 2-23. HAC Bottom-End 30-ft Free Drop with Cold/Hard Foam PropertiesInner Container Containment End Plate Deflection (at Center) 2-60

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-24. HAC Bottom-End 30-ft Free Drop with Cold/Hard Foam Properties Contents Rigid-Body Z-Acceleration Figure 2-25. HAC Bottom-End 30-ft Free Drop with Cold/Hard Foam PropertiesEnergy Time-Histories 2-61

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.7.2 HAC Top-End 30-ft Free Drop with Hot/Soft Foam Properties The HAC top-end free drop of the VP-55 is evaluated using the LS-DYNA model described in Section 2.12.2.3. This case assumes that the package is dropped in a vertical orientation onto the bottom-end of the package from a height of 30 ft. This is accomplished by positioning the VP-55 package bottom in contact with the unyielding horizontal surface (represented with rigid shell elements) and applying an initial velocity of 527.21 in/s in the downward direction. Additionally, a gravitational acceleration of 386.04 in/s² is applied to the model. The time-histories results are filtered using the Butterworth filter at a frequency of 250 Hz.

Figure 2-26 shows a cut-view of the model deformation when the kinetic energy reaches its minimum value at 0.014 seconds of the simulation. Figure 2-27 shows the deflection of the inner container containment end plate (maximum deflection = -1.60 in.) time-history. The Containment Insulation Plug compresses to a thickness of 0.58 in. from an initial thickness of 3.00 in. resulting in 81% compression of the foam (1.00 - 0.58/3.00 = 81%). The Plug Insulator-Drum Lid compresses to a thickness of 2.11 in. from an initial thickness of 2.31 in. resulting in 9%

compression of the foam (1.00 - 2.11/3.00 = 9%). Figure 2-28 shows the rigid-body acceleration time-history of the contents of the Inner Container. The contents reach a peak rigid-body acceleration of 355 g. The energy balance time-history is shown in Figure 2-29. The results show that the initial kinetic energy is converted into strain energy (internal energy) and contact friction energy (sliding energy) due to crushing of the polyurethane foam and contact of the various components. The hourglass energy is low, indicating that the strain energy used to control the hourglass distortion of the models brick elements is acceptably low (less than 10% of the internal energy). The sliding energy remains positive throughout the impact simulation, indicating proper behavior of the modeled contact interfaces.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-26. HAC Top-End 30-ft Free Drop with Hot/Soft Foam PropertiesDeformation at t = 0.014 s Figure 2-27. HAC Top-End 30-ft Free Drop with Hot/Soft Foam PropertiesInner Container Containment End Plate Deflection (at Center) 2-63

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-28. HAC Top-End 30-ft Free Drop with Hot/Soft Foam PropertiesContents Rigid-Body Z-Acceleration Figure 2-29. HAC Top-End 30-ft Free Drop with Hot/Soft Foam PropertiesEnergy Time-Histories 2-64

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.7.3 HAC Side 30-ft Free Drop with Cold/Hard Foam Properties The HAC side free drop of the VP-55 is evaluated using the LS-DYNA model described in Section 2.12.2.3. This case assumes that the package is dropped in a horizontal orientation onto the side of the package (drum clamp ring lug impacting first) from a height of 30 ft. This is accomplished by positioning the VP-55 package on its side with the drum clamp ring lug in contact with the unyielding horizontal surface (represented with rigid shell elements) and applying an initial velocity of 527.21 in/s in the downward direction. Additionally, a gravitational acceleration of 386.04 in/s² is applied to the model. The time-histories results are filtered using the Butterworth filter at a frequency of 400 Hz.

Figure 2-30 shows a cut-view of the model deformation when the kinetic energy reaches its minimum value at 0.0094 seconds of the simulation. Figure 2-31 shows the deflection of the Inner Containment Body (maximum deflection = -3.36 in. near the bottom of the Containment Body) time-history. The Ceramic Blanket compresses to a thickness of 0.57 in. from an initial thickness of 1.98 in. resulting in 71% compression of the blanket (1.00 - 0.57/1.98 = 71%). Figure 2-32 shows the rigid-body acceleration time-history of the contents of the Inner Container. The contents reach a peak rigid-body acceleration of 515 g. The energy balance time-history is shown in Figure 2-33. The results show that the initial kinetic energy is converted into strain energy (internal energy) and contact friction energy (sliding energy) due to crushing of the polyurethane foam and contact of the various components. The hourglass energy is low, indicating that the strain energy used to control the hourglass distortion of the models brick elements is acceptably low (less than 10% of the internal energy). The sliding energy remains positive throughout the impact simulation, indicating proper behavior of the modeled contact interfaces.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-30. NCT Side 30-ft Free Drop with Cold/Hard Foam PropertiesDeformation at t = 0.0094 s Figure 2-31. HAC Side30-ft Free Drop with Cold/Hard Foam Properties Containment Body Deflection (at Bottom) 2-66

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-32. HAC Side 4-ft Free Drop with Cold/Hard Foam PropertiesContents Rigid-Body Z-Acceleration Figure 2-33. HAC Side 30-ft Free Drop with Cold/Hard Foam PropertiesEnergy Time-Histories 2-67

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.2.7.4 HAC Top-Corner 30-ft Free Drop with Hot/Soft Foam Properties The NCT top-corner free drop of the VP-55 is evaluated using the LS-DYNA model described in Section 2.12.2.3. This case assumes that the package is dropped in a vertical orientation onto the bottom-end of the package from a height of 30 ft. This is accomplished by positioning the VP-55 package bottom in contact with the unyielding horizontal surface (represented with rigid shell elements) and applying an initial velocity of 527.21 in/s in the downward direction. Additionally, a gravitational acceleration of 386.04 in/s² is applied to the model. The time-histories results are filtered using the Butterworth filter at a frequency of 400 Hz.

Figure 2-34 shows a cut-view of the model deformation when the kinetic energy reaches its minimum value at 0.0196 seconds of the simulation. Figure 2-34 shows the deflection of the Inner Container Blind Flange (maximum x-deflection = +0.12 in. and z-deflection = -1.96 in. near the corner that impacts). The Containment Insulation Plug compresses to a thickness of 1.81 in. from an initial thickness of 3.00 in. resulting in 40% of the foam (1.00 - 1.96/3.00 = 40%). The Insulator Plug-Drum Lid compresses to a thickness of 2.28 in. from an original thickness of 2.31 in. resulting in 0% of the foam (1.00 - 2.30/2.31 = 0%). The Ceramic Blanket compresses to a thickness of 1.87 in. from an initial thickness of 1.98 in. resulting in 5% compression of the blanket (1.00 -

1.87/1.98 = 5%). Figure 2-35 shows the rigid-body acceleration time-history of the contents of the Inner Container. The contents reach a peak rigid-body acceleration of 133 g. The energy balance time-history is shown in Figure 2-36. The results show that the initial kinetic energy is converted into strain energy (internal energy) and contact friction energy (sliding energy) due to crushing of the polyurethane foam and contact of the various components. The hourglass energy is low, indicating that the strain energy used to control the hourglass distortion of the models brick elements is acceptably low (less than 10% of the internal energy). The sliding energy remains positive throughout the impact simulation, indicating proper behavior of the modeled contact interfaces.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-34. HAC Top-Corner30-ft Free Drop with Cold/Hard Foam Properties Deformation at t = 0.018 s Figure 2-35. HAC Top-Corner 30-ft Free Drop with Cold/Hard Foam Properties Containment Body Deflection (at Bottom) 2-69

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-36. HAC Top Corner 30-ft Free Drop with Cold/Hard Foam PropertiesContents Rigid-Body Z-Acceleration Figure 2-37. HAC Top-Corner 30-ft Free Drop with Cold/Hard Foam PropertiesEnergy Time-Histories 2-70

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.3 High-Capacity Basket Stress Analysis This appendix documents the stress analysis of the High-Capacity Basket (HCB) insert for the VP-55 (see drawing VP-55-HCB-LD) applying the inertial loads documented in Appendix 2.12.2.

As shown in Figure 2-38, the HCB is a support structure for two pipe containers that is designed to provide neutron moderation. Structural support for the HCB is provided by aluminum disks, stiffener arms frames, stainless steel tie rods, and threaded rods. The moderator pipes and separator plate are captured by the support disk, top disk, and bottom disk. Thermal protection of the moderator pipes and separator plate is provided by Rockwool Rockboard insulation. No credit is taken for the insulation in the stress analysis.

Figure 2-38. HCB Solid Model 2-71

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.3.1 Summary of Results To facilitate the evaluation of the HCB, ASME Code Section III, Division 1, Subsection NF, Supports [30], is used to provide acceptance criteria during NCT and HAC. Per Subsection NF, stress intensities are linearized across critical stress locations (see Figure 2-40) and compared to the appropriate allowable stress. Stress locations at a and b indicates the section on the top or bottom outer most surface of the plate.

Free drop stress results are summarized in Table 2-20 through Table 2-23, where the stress results are compared the appropriate Service Level Stress allowable, and margin of safety calculated. The results of the analyses demonstrates that the HCB support structure meets the stress limits defined for Service Level A (NCT) and Level D (HAC).

The lowest margin of safety (MS) for the NCT free drop is +0.85 for bearing stress in the top disk due to the NCT side drop 90-degree orientation (see Figure 2-39). The lowest margin of safety for the HAC free drop is +0.23 for primary membrane stress intensity in the middle support disk due to the HAC side drop 90-degree orientation. For NCT the bearing stresses in the support disks are less than the yield strength.

Bolting evaluation is documented for the threaded connections in Section 2.12.3.8. The lowest margin of safety for the socket head cap screw connection is +10.7 and +3.17 for NCT and HAC, respectively. The lowest margin of safety for the threaded rod connection is +11.9 and +3.85 for NCT and HAC, respectively.

Table 2-20. NCT Side Drop Stress Summary Drop Packaging Stress Maximum Allowable Stress Type MS Orientation Component Location Stress (ksi) Stress (ksi)

Side Drop TD2a Pm 1.6 17.5 +9.64 Top Disk Zero-Degree TD2a Pm+Pb 1.7 26.3 +14.5 SD1a Pm 1.6 17.5 +9.88 Support Disk Middle SD1a Pm+Pb 5.0 26.3 +4.29 Support Disk SDB1b Pm 1.0 17.5 +16.8 Bottom SDB1b Pm+Pb 2.9 26.3 +8.17 SA2 Pm 3.1 17.5 +4.59 Stiffening Arm SA2 Pm+Pb 4.5 26.3 +4.88 Bearing Stress TD1b Pm +1.86 33.7 +17.1 Side Drop 90- TD1a Pm 6.7 17.5 +1.59 Top Disk Degree TD1a Pm+Pb 10.8 26.3 +1.44 SD1b Pm 5.5 17.5 +2.16 Support Disk Middle SD1b Pm+Pb 5.7 26.3 +3.61 Support Disk SDB1b Pm 5.3 17.5 +2.28 Bottom SDB1b Pm+Pb 6.6 26.3 +2.97 SA4 Pm 2.5 17.5 +6.14 Stiffening Arm SA3 Pm+Pb +4.7 26.3 +4.55 Bearing Stress TD2b Bearing +18.2 33.7 +0.85 2-72

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 2-21. NCT Bottom End Drop Stress Summary Packaging Maximum Allowable Stress Location Stress Type MS Component Stress (ksi) Stress (ksi)

BD3 Pm 0.2 17.5 +101 Bottom Disk BD3 Pm+Pb 0.2 26.3 +132 SA1 Pm 0.3 17.5 +53.9 Stiffening Arm SA1 Pm+Pb 0.3 26.3 +81.4 Table 2-22. HAC Side Drop Stress Summary Drop Packaging Stress Maximum Allowable Stress Type MS Orientation Component Location Stress (ksi) Stress (ksi)

Side Drop TD2a Pm 7.0 29.4 +3.21 Top Disk Zero-Degree TD2a Pm+Pb 7.1 44.1 +5.21 SD1a Pm 6.4 29.4 +3.58 Support Disk Middle SD1a Pm+Pb 25.5 44.1 +0.73 SDB1b Pm 6.1 29.4 +3.80 Support Disk Bottom SDB1b Pm+Pb 19.5 44.1 +1.26 SA3 Pm 12.2 29.4 +1.41 Stiffening Arm SA3 Pm+Pb 18.2 44.1 +1.42 Side Drop 90- TD1a Pm 20.6 29.4 +0.42 Top Disk Degree TD1a Pm+Pb 30.6 44.1 +0.44 SD1a Pm 23.9 29.4 +0.23 Support Disk Middle SD1a Pm+Pb 24.6 44.1 +0.79 SDB1b Pm 17.9 29.4 +0.65 Support Disk Bottom SDB1b Pm+Pb 19.6 44.1 +1.25 SA3 Pm 8.1 29.4 +2.63 Stiffening Arm SA3 Pm+Pb 20.7 44.1 +1.13 Table 2-23. HAC Bottom End Drop Stress Summary Packaging Maximum Allowable Stress Location Stress Type MS Component Stress (ksi) Stress (ksi)

BD1 Pm 0.6 29.4 +46.7 Bottom Disk BD1 Pm+Pb 0.7 44.1 +62.2 SA3 Pm 1.3 29.4 +21.7 Stiffening Arm SA4 Pm+Pb 1.4 44.1 +30.0 2-73

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.3.2 Method of Analysis The stresses in the HCB are determined using the finite element code ANSYS Workbench 19.1

[31]. The ANSYS code is used to perform an equivalent linear elastic static stress analysis to evaluate the support structure model during impact using bounding g-loads documented in Appendix 2.12.2. The three-dimensional model of the HCB (STEP file format) is further modified using ANSYS Workbench modelling tools. The full model, except for the Rockwool Rockboard thermal insulation, is used for the ANSYS finite element analysis (FEA) model.

Loads and boundary conditions are applied to the model simulating the conditions that the basket will experience during NCT and HAC. Rigid steel masses are modeled inside the HCB to simulate content loads. For the aluminum plates, post-processing is accomplished by linearizing the stresses across thickness of critical sections. The stress levels are compared to appropriate ASME code allowable stresses and the margin of safety is calculated.

Classical hand calculations are used to evaluate differential thermal expansion of the HCB and documented in Section 2.12.3.7. Forces are extracted at each threaded connection from the analysis results and evaluated using classical hand calculations in Section 2.12.3.8 2.12.3.3 Finite Element Model Description Figure 2-39 shows the Finite Element (FE) Model HCB, generated using ANSYS Workbench [3],

showing the orientations analyzed for end drop and side drop cases. The FE model is generated using a combination of SOLID186 elements (solid structural 20-Node) and SOLID187 (solid structural 10-Node) with a total of 559397 nodes and 201963 elements. The interaction between components is modeled using CONTA173/TARGE170 contact pairs with frictional or no separation contact. Bolted connections are modelled with bounded contact.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-39. HCB Finite Element Model 2-75

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.3.4 Material Properties The mechanical properties of the materials of construction of the HCB structural components are presented in Table 2-24 through Table 2-26. The properties for stainless steel and aluminum are obtained from ASME Section IID [32]. The properties for CPVC are from CORZAN' [33].

Table 2-24. Mechanical Properties of SA-240, 304 Stainless Steel Value at Temperature, °F (°C)

Property, units 70 (21) 150 (66) 200 (93)

Ultimate Strength Su, ksi (MPa) 75 (517) --- 71 (490)

Yield Strength Sy, ksi (MPa) 30 (207) 26.7 (184) 25 (172)

Design Stress Intensity Sm, ksi (MPa) 20 (138) 20 (138) 20 (138)

Modulus of Elasticity E, E+3 ksi (GPa) 28.3 (195) --- 27.5 (190)

Mean Coefficient of Thermal Expansion, , E-6, 8.5 (15.3) 8.8 (15.8) 8.9 (16.0) in./in./°F (E-6, cm/cm/°C)

Poissons Ratio 0.31 Density, lbm/in³ (g/cm³) 0.29 (8.03)

Table 2-25. Structural Properties of ASTM B209 Type 6061-T6 Aluminum Alloy Value at Temperature, °F (°C)

Property, units 70 (21) 200 (93) 300 (149)

Ultimate Strength Su, ksi (MPa) 42 (290) ---

Yield Strength Sy, ksi (MPa) 35 (241) 33.7 (232)

Design Stress Intensity Sm, ksi (MPa) 17.5 (121) 17.5 (121)

Modulus of Elasticity E, E+3 ksi (GPa) 10 (69) 9.6 (66)

Mean Coefficient of Thermal Expansion, , E-6, 12.1 (21.8) 13.0 (23.4) 13.3 (23.9) in./in./°F (E-6, cm/cm/°C)

Poissons Ratio 0.33 Density, lbm/in³ (g/cm³) 0.098 (2.71)

Table 2-26. Structural Properties of CPVC Value at Temperature, °F (°C)

Property, units 73 (22.8) 150 (65.6)

Tensile Yield Strength Sy, ksi (MPa) 8 (55) 5.3 (36.5)

Modulus of Elasticity E, E+3 ksi (GPa) 0.415 (2.86) ---

Mean Coefficient of Thermal Expansion, , E-6, in./in./°F (E-6, 0.34 (0.612) cm/cm/°C)

Poissons Ratio 0.33 Density, lbm/in³ (g/cm³) 0.056 (1.55) 2-76

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.3.5 Boundary Conditions, Loads, and Initial Conditions To simulate the interface with the VP-55, a quadrant of the inner shell is modelled with frictional contact defined between surfaces. For the bottom end drop, compression only support is defined on the lower surface of the bottom disk to simulate the Ethafoam spacer (see VP-55-HCB-LD, Part 15). Additional stability is provided during the side drop by locking the rotation about the X-axis and lateral motion along the Z-axis at a single node at the axial center line of the model (see triad in Figure 2-39).

The HCB is designed to hold 2 pipe containers (VP-55-2R) with the mass limit defined by the established maximum gross weight of 750 pounds (see Table 2-2). Each moderator pipe is loaded with a 146-pound rigid mass with densities adjusted to compensate for the removal of the thermal insulation from the model, which results in a total mass of 292 pounds. When the inertial mass of the HCB is included, the total payload weight equals a minimum 350 pounds. The total applied load is verified by checking the reaction forces for each case.

The HCB is analyzed for the side drop (90° and 0°) and bottom end drop orientations. The top end drop, or top corner drop are omitted since the pipe containers are held in position by the cavity foam insert. With the foam insert supporting most of the load, HCB stresses are bounded by the side drop and bottom end drop. From Section 2.12.2.1, the bounding NCT and HAC accelerations applied to the ANSYS model are presented in Table 2-27.

Table 2-27. Acceleration Loads Drop Case Side (g) Bottom End (g)

NCT (4-ft Drop) 121 105 HAC (30-ft Drop) 515 394 An initial temperature of 71.6°F is applied to the model.

2.12.3.6 Stress Criteria The High-Capacity Basket (HCB) is designed to stay structurally intact under NCT and HAC free drop events. Stress analyses are performed to ensure there is no structural collapse or separation of components due to excessive compressive, bending, or tensile stresses.

The stress analysis methodology for the HCB uses traditional linear elastic stress criteria defined by the ASME code. Classified as a shoring device, the HCB is analyzed in accordance with paragraph NF-3220plate and shell-type Class 1 supports of ASME Code,Section III, Division 1, Subsection NF. This section of the ASME code establishes Service Level A limits. Table NF-3221.2-1, of ASME Section III, Appendix F, is used to define Service Level D limits [34]. Per F-1332.3, during HAC bearing stresses are not evaluated. Allowable stress limits are summarized in Table 2-28.

Stresses are evaluated at critical sections where linearized averaging is used to determine the stress intensity value. Figure 2-40 shows the location of the critical stress sections.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 2-28. Allowable Stress Design Criteria for Plates and Shells Allowable Stress Limits Stress Type Service Level D Service Level A (NCT)

(HAC)

Greater of 1.2Sy and Primary Membrane Stress Intensity (Pm) Sm 1.5Sm, but 0.7Su Primary Membrane + Bending Stress Intensity 1.5Sm 150% of Pm allowable (PL or Pm + Pb)

Average Bearing Stress Sy ---

Average Shear Stress 0.6Sm 0.42Su NCT and HAC stress allowables for bolted joints are provided in ASME NF-3324.6 and Section III, Appendix F, F-1335 [34], respectively. These allowables are used for the connecting rods and bolt threads. Allowable Stress limits for threaded connections are summarized in Table 2-29.

Table 2-29. Allowable Stress Criteria for Bolted Connections Allowable NCT (Level A) HAC (Level D)

Tensile Stress "# "# the smaller of 0.7Su and Sy 3.33 0.62$

Shear Stress  %#  %# the smaller of 0.42Su and 0.6Sy 5

Bearing Sy # 2.1Su 2-78

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 2-40. Linearized Stress Location 2-79

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.3.7 Differential Thermal Expansion The High-Capacity Basket (HCB) is designed with enough axial and radial clearances within the VP-55 cavity to permit the HCB to expand freely under NCT. The nominal axial and radial clearances for all HCB configurations are 0.325-inch and 0.1875-inch, respectively. Based on the temperature results from Section 3.5.4, differential thermal expansion between the HCB and VP-55 cavity is evaluated for NCT assuming an upper bound temperature of 138°F based on the VP-55 inner surface. Neglecting thermal expansion of the VP inner cavity shell, the axial and radial thermal is:

DL = x L x (138°F - 70°F) = 0.021 in.,

DR = x R x (138°F - 70°F) = 0.007 in.,

where, L = 22.8 in., Max. length of HCB, R = 7.25 in., Max. outer radius of HCB shell,

= 13.3 x 10-6 in/in/°F, Mean coefficient of thermal expansion of Aluminum 6061.

The results show that the axial and radial expansion of the HCB is less than the nominal axial and radial clearances provided between the HCB and VP cavity. The nominal axial and radial clearances between the HCB and VP cavity are reduced to 0.30-inch and 0.18-inch, respectively, with thermal expansion. Therefore, the HCB will expand freely within the VP cavity under.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2.12.3.8 Threaded Connections The loads at the fastener connections are obtained by retrieving the force reactions at the contact surfaces of the fasteners from the ANSYS impact model. Summary of the forces are presented in Table 2-30 and Table 2-31 for the threaded connecting rod and threaded rod, respectively. The stresses at the threaded joints are evaluated using classical equations. The fasteners are depicted in Figure 2-41, where the numberings represent top and bottom.

Figure 2-41. High-Capacity basket (HCB) Fasteners 2-81

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 2-30. Threaded Connection Force Summary Fastener NCT Load (lbf) HAC Load (lbf)

Number NCT Side 0° NCT Side 90° NCT End HAC Side 0° HAC Side 90° HAC End 1 290.5 122.9 9.1 1030.7 151.1 13.4 2 288.9 196.7 9.8 1017.1 210.4 12.9 3 123.1 192.2 9.7 146.6 205.4 12.7 4 124.7 124 9.4 148.7 150.8 12.8 5 256.4 136.4 39.7 740 252.3 145.3 6 258.1 203.9 39.9 748.1 421.4 145.8 7 94.3 205.1 39.6 148.6 427.9 145.4 8 92.3 133.1 39.6 142.5 248.7 145.3 Max 290.5 205.1 39.9 1030.7 427.9 145.8 Table 2-31. Threaded Rod and Hex Nut Connection Force Summary Fastener NCT Load (lbf) HAC Load (lbf)

Number NCT Side 0° NCT Side 90° NCT End HAC Side 0° HAC Side 90° HAC End 1a 14.1 27.7 1.20 6.5 24.2 4.50 2a 13.7 23.4 1.20 6.2 20.3 4.50 3a 52.4 24.4 1.20 174.4 21.3 4.50 4a 51.7 27.9 1.20 172.7 24.4 4.50 5a 23.6 2.2 2.00 21.3 5.9 7.40 6a 23.3 2.9 2.00 21.2 5.9 7.40 7a 12.7 2.8 1.90 44.3 5.9 7.40 8a 13.0 2.1 1.90 44.5 5.9 7.40 Max 52.4 27.9 2.0 174.4 160.0 7.40 Stresses in the tie rod and threaded rod are calculated using the formulas for threaded fasteners presented in Machinerys Handbook [35]. Allowable stresses are presented in Table 2-29. The bounding NCT and HAC results are presented in Table 2-32 through Table 2-35. The results show that the threaded connections have sufficient margin of safety during NCT and HAC.

Table 2-32. Hex Socket Head Cap Screw - NCT Stress Summary External thread Internal thread Description Unit Tensile stress shear shear Force lbf 290.5 290.5 290.5 Area in² 0.160 0.320 0.4334 Stress ksi 1.82 0.91 0.67 Allowable Stress ksi 21.3 14.2 14.2 Margin of Safety --- +10.7 +14.6 +20.2 2-82

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 2-33. Threaded Rod - NCT Stress Summary External thread Internal thread Description Unit Tensile stress shear shear Force lbf 52.4 52.4 52.4 Area in² 0.0318 0.0636 0.0931 Stress ksi 1.65 0.82 0.56 Allowable Stress ksi 21.3 14.2 14.2 Margin of Safety --- +11.9 +16.3 +24.4 Table 2-34. Hex Socket Head Cap Screw - HAC Stress Summary External thread Internal thread Description Unit Tensile stress shear shear Force lbf 1030.7 1030.7 1030.7 Area in² 0.160 0.320 0.4334 Stress ksi 6.4 3.2 2.4 Allowable Stress ksi 26.7 16.0 16.0 Margin of Safety --- +3.17 +4.01 +5.68 Table 2-35. Threaded Rod - HAC Stress Summary External thread Internal thread Description Unit Tensile stress shear shear Force lbf 174.4 174.4 174.4 Area in² 0.0318 0.0636 0.0931 Stress ksi 5.5 2.70 1.90 Allowable Stress ksi 26.7 16.0 16.0 Margin of Safety --- +3.85 +4.93 +7.43 2-83

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 CONTENTS 3 THERMAL EVALUATION ....................................................................................................... 3-1 3.1 Description of the Thermal Design ........................................................................................ 3-2 3.1.1 Design Features ........................................................................................................................................ 3-2 3.1.2 Contents Decay Heat .............................................................................................................................. 3-3 3.1.3 Summary Tables of Temperatures ................................................................................................... 3-4 3.1.4 Summary Tables of Maximum Pressures ...................................................................................... 3-5 3.2 Material Properties and Component Specifications ........................................................ 3-6 3.2.1 Material Properties ................................................................................................................................. 3-6 3.2.2 Component Specifications .................................................................................................................... 3-9 3.3 Thermal Evaluation for Normal Conditions of Transport (NCT) ............................... 3-11 3.3.1 Heat and Cold .......................................................................................................................................... 3-13 3.3.2 Maximum Normal Operating Pressure ........................................................................................ 3-21 3.4 Thermal Evaluation for Hypothetical Accident Conditions (HAC) ............................ 3-22 3.4.1 Initial Conditions ................................................................................................................................... 3-22 3.4.2 Fire Test Conditions ............................................................................................................................. 3-23 3.4.3 Maximum Temperatures and Pressure ....................................................................................... 3-25 3.4.4 Maximum Thermal Stresses ............................................................................................................. 3-28 3.4.5 Accident Conditions for Fissile Material Packages for Air Transport ............................ 3-28 3.5 Appendix ....................................................................................................................................... 3-29 3.5.1 References ................................................................................................................................................ 3-30 3.5.2 Thermal Analysis of 1S/2S UF6 Cylinders in the VP-55........................................................ 3-31 3.5.3 Thermal Analysis of the VP-55 with no Containment Insulation Plug .......................... 3-45 3.5.4 Thermal Analysis of the VP-55 with High-Capacity Basket ................................................ 3-57 3.5.5 Supporting Classical Equations....................................................................................................... 3-68 3-i

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 TABLES TABLE 3-1 VERSA-PAC OVERALL AND THERMAL INSULATION DIMENSIONS ....................................................................................... 3-3 TABLE 3-2 NCT STEADY STATE THERMAL EVALUATION RESULTS - STANDARD VERSA-PAC CONFIGURATION .......................... 3-4 TABLE 3-3 HAC TRANSIENT THERMAL EVALUATION RESULTS - STANDARD VERSA-PAC CONFIGURATION ................................ 3-5 TABLE 3-4 THERMAL PROPERTIES OF ASTM A-36 CARBON STEEL .................................................................................................... 3-6 TABLE 3-5 THERMAL PROPERTIES OF SERIES 525 FIBERGLASS ............................................................................................................ 3-7 TABLE 3-6 THERMAL PROPERTIES OF CERABLANKET (6 PCF) ............................................................................................................... 3-7 TABLE 3-7 THERMAL PROPERTIES OF DRY AIR ........................................................................................................................................ 3-8 TABLE 3-8 THERMAL PROPERTIES OF 12-PCF POLYURETHANE FOAM ................................................................................................. 3-8 TABLE 3-9 THERMAL EMISSIVITY VALUES ................................................................................................................................................. 3-9 TABLE 3-10 TEMPERATURE LIMITS ......................................................................................................................................................... 3-10 TABLE 3-11

SUMMARY

OF NCT BOUNDARY CONDITIONS ................................................................................................................... 3-12 TABLE 3-12 INSOLATION DATA ................................................................................................................................................................ 3-13 TABLE 3-13 NCT STEADY STATE THERMAL EVALUATION RESULTS ................................................................................................. 3-18 TABLE 3-14 HAC TRANSIENT THERMAL EVALUATION

SUMMARY

RESULTS .................................................................................... 3-25 TABLE 3-15

SUMMARY

OF BOUNDARY CONDITIONS ............................................................................................................................. 3-32 TABLE 3-16 THERMAL PROPERTIES OF POLYETHYLENE FOAM .......................................................................................................... 3-33 TABLE 3-17 NCT STEADY STATE RESULTS - 1S/2S UF6 CYLINDER VP-55 CONFIGURATION .................................................... 3-36 TABLE 3-18 HAC FIRE TRANSIENT RESULTS - 1S/2S UF6 CYLINDER VP-55 CONFIGURATION ................................................ 3-41 TABLE 3-19

SUMMARY

OF BOUNDARY CONDITIONS ............................................................................................................................. 3-46 TABLE 3-20 NCT STEADY STATE THERMAL EVALUATION RESULTS -VP-55 CONFIGURATION WITHOUT CONTAINMENT INSULATION PLUG .............................................................................................................................................................................. 3-49 TABLE 3-21 HAC TRANSIENT THERMAL EVALUATION RESULTS - VP-55 CONFIGURATION WITHOUT CONTAINMENT INSULATION PLUG .............................................................................................................................................................................. 3-53 TABLE 3-22

SUMMARY

OF BOUNDARY CONDITIONS ............................................................................................................................. 3-57 TABLE 3-23 THERMAL PROPERTIES OF ROCKBOARD 60 ................................................................................................................. 3-58 TABLE 3-24 THERMAL PROPERTIES OF CPVC ....................................................................................................................................... 3-58 TABLE 3-25 THERMAL PROPERTIES OF ALUMINUM ALLOY (6061).................................................................................................. 3-59 TABLE 3-26 STAINLESS STEEL (304) PROPERTIES .............................................................................................................................. 3-59 TABLE 3-27 NCT STEADY STATE THERMAL EVALUATION RESULTS ................................................................................................. 3-61 TABLE 3-28 HAC TRANSIENT THERMAL EVALUATION

SUMMARY

RESULTS .................................................................................... 3-64 TABLE 3-29 CONSTANTS 'C' AND 'M' FOR THE NUSSELT NUMBER CALCULATION OF A CYLINDER IN CROSS FLOW .................. 3-70 3-ii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 FIGURES FIGURE 3-1 VP-55 QUARTER SYMMETRY THERMAL MODEL ................................................................................................................. 3-1 FIGURE 3-2 QUARTER SYMMETRY FINITE ELEMENT MODEL OF THE VP-55 ................................................................................... 3-12 FIGURE 3-3 NCT BOUNDARY CONDITIONS FOR CASE I (HOT: INTERNAL WATTAGE + SOLAR INSOLATION) ............................ 3-14 FIGURE 3-4 NCT BOUNDARY CONDITIONS FOR CASE II (HOT: INTERNAL WATTAGE + NO SOLAR INSOLATION)..................... 3-15 FIGURE 3-5 NCT BOUNDARY CONDITIONS FOR CASE III (COLD: INTERNAL WATTAGE + NO INSOLATION) ............................. 3-16 FIGURE 3-6 NCT BOUNDARY CONDITIONS FOR CASE IV (COLD: NO INTERNAL WATTAGE + NO INSOLATION) ....................... 3-17 FIGURE 3-7 NCT TEMPERATURE CONTOUR-CASE I (HOT: INTERNAL WATTAGE + SOLAR INSOLATION) ................................... 3-19 FIGURE 3-8 NCT TEMPERATURE CONTOUR-CASE II (HOT: INTERNAL WATTAGE + NO INSOLATION)....................................... 3-19 FIGURE 3-9 NCT TEMPERATURE CONTOUR-CASE III (COLD: INTERNAL WATTAGE + NO INSOLATION) ................................... 3-20 FIGURE 3-10 NCT TEMPERATURE CONTOUR-CASE IV (COLD: NO INTERNAL WATTAGE + NO INSOLATION) .......................... 3-20 FIGURE 3-11 NCT RESULTS AS INITIAL CONDITIONS OF HAC ............................................................................................................ 3-22 FIGURE 3-12 HAC FIRE BOUNDARY CONDITIONS ................................................................................................................................. 3-23 FIGURE 3-13 HAC COOL-DOWN (POST-FIRE) BOUNDARY CONDITIONS .......................................................................................... 3-24 FIGURE 3-14 VP-55 HAC PACKAGE TEMPERATURE-TIME HISTORY PLOT .................................................................................... 3-26 FIGURE 3-15 VP-55 HAC CONTAINMENT TEMPERATURE-TIME HISTORY PLOT .......................................................................... 3-26 FIGURE 3-16 HAC THERMAL ANALYSIS MAXIMUM TEMPERATURE CONTOURS .............................................................................. 3-27 FIGURE 3-17 HAC THERMAL ANALYSIS MAXIMUM TEMPERATURE CONTOURS AT SEVERAL TIMES ........................................... 3-28 FIGURE 3-18 ANSI N14.1 1S CYLINDER ................................................................................................................................................ 3-31 FIGURE 3-19 ANSI N14.1 2S CYLINDER ................................................................................................................................................ 3-31 FIGURE 3-20 QUARTER SYMMETRY FINITE ELEMENT MODEL OF THE VERSA-PAC ........................................................................ 3-34 FIGURE 3-21 NCT BOUNDARY CONDITIONS ........................................................................................................................................... 3-35 FIGURE 3-22 NCT EVALUATION PACKAGE TEMPERATURE CONTOUR ............................................................................................... 3-37 FIGURE 3-23 NCT TEMPERATURE CONTOUR SHOWING INTERIOR SURFACE OF FOAM INSERT .................................................... 3-37 FIGURE 3-24 HAC FIRE INITIAL BODY TEMPERATURE ........................................................................................................................ 3-38 FIGURE 3-25 HAC FIRE BOUNDARY CONDITIONS ................................................................................................................................. 3-39 FIGURE 3-26 HAC POST FIRE COOL DOWN BOUNDARY CONDITIONS ............................................................................................... 3-40 FIGURE 3-27 VP-55 1S/2S UF6 CYLINDERS - CONTAINMENT INNER SURFACE TEMP. WITH FOAM LINERS .......................... 3-41 FIGURE 3-28 VP-55 1S/2S UF6 CYLINDERS ENTIRE PACKAGE HAC TEMPERATURE HISTORY................................................. 3-42 FIGURE 3-29 VP-55 1S/2S UF6 CYLINDERS PACKAGE CONTAINMENT HAC TEMPERATURE HISTORY ................................... 3-42 FIGURE 3-30 HAC THERMAL ANALYSIS MAXIMUM TEMPERATURE CONTOUR ................................................................................ 3-43 FIGURE 3-31 HAC THERMAL ANALYSIS PACKAGE MAXIMUM TEMPERATURE CONTOUR AT DIFFERENT TIMES....................... 3-44 FIGURE 3-32 VP-55 WITHOUT CONTAINMENT INSULATION PLUG (PART IG) ............................................................................... 3-45 FIGURE 3-33 FINITE ELEMENT MODEL OF THE VERSA PACK QUARTER SYMMETRY MODEL ........................................................ 3-47 FIGURE 3-34 NCT BOUNDARY CONDITIONS ........................................................................................................................................... 3-48 FIGURE 3-35 NCT EVALUATION PACKAGE TEMPERATURE CONTOUR ............................................................................................... 3-50 FIGURE 3-36 NCT TEMPERATURE CONTOUR INTERIOR SURFACE ..................................................................................................... 3-50 FIGURE 3-37 HAC FIRE BOUNDARY CONDITIONS ................................................................................................................................. 3-51 FIGURE 3-38 HAC POST FIRE COOL DOWN BOUNDARY CONDITIONS ............................................................................................... 3-52 FIGURE 3-39 VP-55 ENTIRE PACKAGE HAC TEMPERATURE HISTORY (WITHOUT CONTAINMENT INSULATION PLUG)

MAXIMUM TEMPERATURE HISTORY ............................................................................................................................................... 3-54 FIGURE 3-40 VP-55 (WITHOUT CONTAINMENT INSULATION PLUG) CONTAINMENT TEMPERATURE HISTORY ....................... 3-54 FIGURE 3-41 HAC THERMAL ANALYSIS CONTAINMENT MAXIMUM TEMPERATURE CONTOURS .................................................. 3-55 FIGURE 3-42 HAC THERMAL ANALYSIS PACKAGE MAXIMUM TEMPERATURE CONTOUR DURING FIRE AND COOL DOWN ..... 3-56 FIGURE 3-43 VP-55 WITH HIGH-CAPACITY BASKET (HCB) .............................................................................................................. 3-57 FIGURE 3-44 NCT BOUNDARY CONDITIONS ........................................................................................................................................... 3-60 FIGURE 3-45 NCT EVALUATION PACKAGE TEMPERATURE CONTOUR ............................................................................................... 3-62 FIGURE 3-46 NCT EVALUATION HCB TEMPERATURE CONTOUR....................................................................................................... 3-62 FIGURE 3-47 HAC FIRE BOUNDARY CONDITIONS ................................................................................................................................. 3-63 FIGURE 3-48 HAC POST FIRE COOL DOWN BOUNDARY CONDITIONS ............................................................................................... 3-64 FIGURE 3-49 VP-55-HCB ENTIRE PACKAGE MAXIMUM TEMPERATURE HISTORY ....................................................................... 3-65 3-iii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 FIGURE 3-50 VP-55 PACKAGE WITH HCB TEMPERATURE HISTORY ................................................................................................ 3-65 FIGURE 3-51 HAC THERMAL ANALYSIS MAXIMUM TEMPERATURE CONTOUR (A-C) ..................................................................... 3-66 FIGURE 3-52 HAC THERMAL ANALYSIS PACKAGE MAXIMUM TEMPERATURE CONTOUR AT DIFFERENT TIMES (A-C) ............ 3-67 3-iv

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3 THERMAL EVALUATION This chapter documents the thermal performance of the Versa-Pac (Figure 3-1) during Normal Conditions of Transport (NCT) and Hypothetical Accident Conditions (HAC) per the requirements of 10 CFR 71.71 and 10 CFR 71.73, respectively [1]. The thermal analysis results show that the NCT maximum exterior surface temperature meets the non-exclusive use shipment requirement of 10 CFR 71 § 71.43(g). During HAC, the inner cavity stays below 600°F (316°C). Therefore, it can be predicted that the contents will remain in solid form because the radioactive content is a stable solid that does not undergo a change of state below 600°F (316°C). For the 1S/2S UF6 Cylinder configuration, the inner cavity temperature reaches a maximum temperature of 245°F (118°C) during HAC, which is less than the 250°F (121°C) limit established in Table 1 of ANSI N14.1 [2]. To transport 1S/2S cylinders, the inner cavity of the VP-55 must be lined with a minimum 2 inch (5.08 cm) thick polyethylene foam liner with a minimum foam density of 9 pcf (144 kg/m3). For the case where the containment insulation plug Part (IG) is removed, the maximum inner cavity temperature is 425°F (218°C) during HAC.

Drum Lid (Part DL)

Polyurethane Foam Plug (Part IC)

Containment Lid (Part PD)

Air Gaps Containment Foam Plug (Part IG) 55 Gallon Drum (Part DA)

Ceramic Blanket (Part IA)

Cavity Air Containment End Plate (Part PB)

Polyurethane Foam Plug (Part ID)

Ceramic Paper (Part ID)

Figure 3-1 VP-55 Quarter Symmetry Thermal Model 3-1

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.1 Description of the Thermal Design 3.1.1 Design Features The VP-55 Versa-Pac consists of a 10ga containment body, with payload cavity nominal dimensions of a 15 diameter and 23-1/8 height, centered within an insulated 55-gallon drum.

Detail drawings of the VP-55 are provided in the VP-55 licensing drawing in Appendix 1.4.1.

The nominal exterior dimensions of the assembled VP-55 are 23-3/16 diameter and 34-3/4 height. The payload cavity is protected from water intrusion with a gasketed lid that is closed with twelve 1/2 diameter bolts. Under the containment lid, there is a 3 thick polyurethane insulation plug for added thermal insulation when the contents require extra protection. Exterior to the containment lid, the 55-gallon drum lid is modified with a 20ga steel encapsulated polyurethane insulation plug. The gasketed drum lid is closed with four 1/2 diameter bolts and a standard drum ring. A gasket at the drum lids stiffening ring provides a third barrier against water in-leakage.

The 55-gallon drum is strengthened with four longitudinal stiffeners fabricated from 1-1/4 carbon steel square tubing equally spaced around the circumference of the drum. The outer and inner liners provide additional radial stiffness to the drum. A 1/2 thick fiberglass ring and fiberglass spacers are used as thermal breaks at the payload cavity flange. The thermal breaks are sandwiched between the steel components and effectively limit the flow of heat to the payload cavity through the steel flange components. The volume between the inner liner and the 10ga containment body is filled with ceramic blanket insulation. Furthermore, the bottom of the containment body is insulated with polyurethane foam and the gap on the bottom, between the bottom reinforcing plate and the drum bottom, is filled with sheets of ceramic paper (Appendix 1.4.1).

The VP-110 consists of a 10ga containment body, with payload cavity nominal dimensions of 21 diameter and 29-3/4 height, centered within an insulated 110-gallon drum. Detail drawings of the VP-110 are provided in the VP-110 licensing drawing in Appendix 1.4.1. The nominal exterior dimensions of the assembled VP-110 package are 30-7/16 diameter and 42-3/4 height. The basic design of the VP-110 is identical to that of the 55-gallon Versa-Pac, except for the larger exterior dimensions and payload cavity dimensions. The thickness of the walls and insulation remain the same.

The Versa-Pac design allows for the use of two neoprene pads, a 1/8 bottom pad, and a 3/8 top pad. The pads serve the purpose of protecting the inner containment shell during repeated use.

The use of these pads is optional. The Versa-Pac overall and thermal insulating components dimensions are documented in Table 3-1 below.

As documented in this section, the basic design of the VP-110 is identical to that of the VP-55, except for the larger exterior diameter and payload cavity diameter. The thickness of the walls and insulation remain the same. Further, the payload heat decay in the VP-110 model is the same as that of the VP-55. However, because VP-110 is larger in size, the volumetric decay heat load is less than that of VP-55. Therefore, the VP-55 analysis bounds the VP-110.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 3-1 Versa-Pac Overall and Thermal Insulation Dimensions Stock Part Name VP-55 VP-110 Number Payload Cavity Nominal N/A 15 ID x 23-1/8 21 ID x 29-3/4 Package Exterior Nominal N/A 23-3/16OD x 34-3/4 30-7/16OD x 42-3/4 Ceramic Blanket Insulation IA 1-1/2 - 2 thick 1-1/2 - 2 thick Fiberglass Ring IE 1/2 thick 1/2 thick Fiberglass Spacers IF 1/2 thick 1/2 thick Plug Insulator-Drum Lid IC 19 Dia. x 2-5/16 thick 26-4/8 Dia. x 3-7/16 thick Air Gap Above Containment Lid N/A 5/8 1 Containment Insulation Plug IG 14-7/8 Dia. x 3 thick 20-7/8 Dia. x 3 thick Plug Insulator-Bottom Body IB 2-3/4 thick 2-3/8 thick 1/8-thick sheets (at least 1/8 thick sheets (at least Ceramic Paper ID one sheet) one sheet)

Reference:

Appendix 1.4.1 3.1.2 Contents Decay Heat The decay heat for the payload is limited to 11.4 W total for the VP-55 and VP-110, with no single item having a decay heat greater than 20 W/m3.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.1.3 Summary Tables of Temperatures 3.1.3.1 NCT Temperature Summary Per the requirements of 10 CFR 71.71(c)(1), the Versa-Pac standard configuration, the VP-55 1S/2S UF6 cylinder configuration, and the VP-55 without the containment insulation plug part (IG) configuration are evaluated for Normal Conditions of Transport. This includes a steady-state thermal analysis simulating exposure to a 100°F (37.8°C) ambient temperature in still air and insolation as specified in Table 3-12. The temperatures of key components are summarized in Table 3-2 for the standard configuration, 1S/2S, and No IG, with the full NCT results in Section 3.3, Appendix 3.5.2.4, and Appendix 3.5.3.4, respectively.

Table 3-2 NCT Steady State Thermal Evaluation Results - Standard Versa-Pac Configuration Temperature °F (°C) Maximum Part Component Allowable Number VP-55 1S/2S No IG Temp °F (°C)

Containment body PA 147 (64) 139 (59) 147 (64)

Containment end plate PB 147 (64) 134 (57) 147 (64)

Containment insulation plug IG 177 (80) 139 (59) 270 (132)

Gasket GB 143 (61) 139 (59) 143 (62) 500 (260)

Containment lid (Blind flange) PD 143 (62) 139 (59) 143 (62)

Drum lid DL 154 (68) 154 (68) 154 (68)

Drum lid gasket GA 144 (62) 144 (62) 145 (63)

Drum DA 144 (62) 143 (62) 144 (62)

Package surface DA/DL 154 (68) 154 (68) 154 (68)

Air Volume Maximum 232 (111) 600 (316)

Air Volume Average 191 (88) 600 (316)

Containment Cavity Surface 147 (64) 600 (316)

Foam liner for 1S/2S Cylinder 138 (59) 250 (121) 3-4

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.1.3.2 HAC Temperature Summary The Versa-Pac must survive the HAC thermal analysis such that containment is maintained, and the structural integrity is sufficient for the criticality control credited in Section 6. The temperatures of key components are summarized in Table 3-3 for the standard configuration, 1S/2S, and No IG, with the full HAC results in Section 3.4., Appendix 3.5.2.5 and Appendix 3.5.3.5, respectively.

As shown in Table 3-3, the HAC fire does not adversely affect the Versa-Pacs structural or containment configurations. The Inner Cavity Air Volume remains below 600°F (316°C) for the Versa-Pac standard configuration. For the 1S/2S UF6 cylinder configuration results, the foam liner surface temperature remains below the maximum UF6 cylinder temperature of 250°F (121°C), as stated in Table 1 of ANSI N14.1. For the case where the containment insulation plug Part (IG) is removed, the maximum inner cavity temperature is 425°F (218°C) which is also below 600°F (316°C) for the Versa-Pac standard configuration.

Table 3-3 HAC Transient Thermal Evaluation Results - Standard Versa-Pac Configuration Temperature °F (°C) Maximum Part Component Allowable Temp Number VP-55 1S/2S No IG °F (°C)

Air volume maximum 399 (204) 600 (316)

Air volume average 351 (177) 600 (316)

Foam liner average 221 (105) 250 (121)

Foam liner inner surface 245 (118) 250 (121)

Containment cavity surface 380 (193) 425 (218) 600 (316)

Containment plug surface IG 380 (193) 340 (171) 600 (316)

Containment lid (Blind flange) PD 423 (217) 413 (212) 433 (223) 2600 (1427)

Containment body PA 412 (211) 400 (204) 423 (217) 2600 (1427)

Containment Gasket GB 425 (219) 416 (213) 436 (224) 1000 (538)

Inner flange PH 434 (223) 425 (219) 445 (229) 2600 (1427)

Drum lid DL 1457 (792) 1456 (791) 1456 (791) 2600 (1427)

Drum DA 1461 (794) 1460 (793) 1460 (793) 2600 (1427) 3.1.4 Summary Tables of Maximum Pressures Due to permeation in the silicone coating of the cavity seal, the maximum normal and HAC operating pressure are expected to be near atmospheric pressure. However, based on the maximum cavity temperatures, the maximum hypothetical pressures for NCT and HAC are approximately 3.3 psig (124 kPa) and 9.8 psig (169 kPa), respectively. Both are well below the 15 psig (205 kPa) containment pressure rating. Thus, the Versa-Pac meets the requirements of 10 CFR 71 [1].

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.2 Material Properties and Component Specifications 3.2.1 Material Properties The thermal properties for the Versa-Pac are presented in the following subsections. When available, temperature-dependent properties were used in the analyses. These properties are listed for both the materials of construction of the Versa-Pac and the air fill gas in the inner cavity.

3.2.1.1 ASTM A-36 Carbon Steel The steel of the Versa-Pac is modeled as ASTM A-36 carbon steel with the temperature-dependent thermal conductivities, thermal diffusivities, and specific heats as listed in Table 3-4.

Table 3-4 Thermal Properties of ASTM A-36 Carbon Steel Thermal Thermal Temperature Density Specific Heat 2 Conductivity Diffusivity

(°F) 1 (lbm/ft3) (BTU/lbm*°F)

(BTU/hr*ft*°F) (ft2/hr) 70 (21) 34.9 0.700 0.103 100 (38) 34.7 0.676 0.106 250 (121) 33.0 0.585 0.117 300 (149) 32.3 0.560 0.119 500 (260) 483.84 29.4 0.474 0.128 700 (371) 26.6 0.394 0.140 900 (482) 23.8 0.318 0.155 1000 (538) 22.4 0.283 0.164 1500 (816) 15.5 0.166 0.193

Reference:

[3] Density: Table PRD, Carbon steels, Page 744.

[3] Thermal Properties: Table TCD, Material Group A - Plain Carbon, Page 726.

Note: 1 See Assumption 5.2.1.b regarding this gap in temperature data.

2 Specific Heat calculated using the following formula: SH = TC/*TD.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.2.1.2 Series 525 Fiberglass This fiberglass component is used to provide thermal break. The material consists of a glass fiber reinforced polyester or vinyl ester resin matrix with glass reinforcements. The thermal properties of this fiberglass are documented in Table 3-5. Because the density is provided with a tolerance band, the highest value is conservatively used in this thermal analysis.

Table 3-5 Thermal Properties of Series 525 Fiberglass Temperature Density Thermal Conductivity

°F (°C) (lbm/in3) (BTU*in/hr*ft2*°F) 75 (24) 0.062 - 0.070 4.0

Reference:

Appendix 1.4.5: Density and Thermal Conductivity.

3.2.1.3 Cerablanket Cerablanket is used as an insulating material with material properties as documented in Table 3-6. As documented in Section 1.4.4, the Cerablanket can be either 6 pcf or 8 pcf. Because the thermal conductivity of Cerablanket decreases as density increases (Appendix 1.4.4), the 6 pcf is assumed to let more heat into the package during hypothetical fire accident. Therefore, the 6 pcf foam is conservatively used in this analysis.

Table 3-6 Thermal Properties of Cerablanket (6 pcf)

Temperature Density Thermal Conductivity Specific Heat

°F (°C) lbm/ft3 BTU*in/(hr*ft2*°F) W/(m*k) J/(kg*K) BTU/lbm*°F 75 (24) 0.47 0.07 500 (260) 0.47 0.07 6.0 1130 0.270 1000 (538) 1.06 0.15 1500 (816) 1.90 0.27

Reference:

Appendix 1.4.4: Density and Thermal Conductivity.

[4] Specific Heat: Blanket Products Table, Cerablanket @1090°C.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.2.1.4 Dry Air The inner cavity fluid is modeled as dry air. No convection is modeled in this analysis, only conduction. The dry air properties are documented in Table 3-7.

Table 3-7 Thermal Properties of Dry Air Temperature Density Thermal Conductivity Specific Heat BTU*in/ BTU/

K °F kg/m³ lbm/ft³ W/(m*K) J/(kg*K) hr*ft2*°F lbm*°F 300 80 1.1614 7.250E-02 0.0263 0.182 1007 0.241 350 170 0.995 6.212E-02 0.03 0.208 1009 0.241 400 260 0.8711 5.438E-02 0.0338 0.234 1014 0.242 450 350 0.774 4.832E-02 0.0373 0.259 1021 0.244 550 530 0.6329 3.951E-02 0.0439 0.304 1040 0.248 650 710 0.5356 3.344E-02 0.0497 0.345 1063 0.254 750 890 0.4643 2.899E-02 0.0549 0.381 1087 0.260 850 1070 0.4097 2.558E-02 0.0596 0.413 1110 0.265 950 1250 0.3666 2.289E-02 0.0643 0.446 1131 0.270 1100 1520 0.3166 1.977E-02 0.0715 0.496 1159 0.277

Reference:

[5] Thermal Properties: Table A.4, Air, Page 995.

3.2.1.5 Polyurethane Foam Polyurethane foam is also used in providing thermal insulation. As specified in Appendix 1.4.3, the densities of the foam can range from 5 pcf to 11 pcf. Because thermal conductivity of the polyurethane foam increases with density [6], 12 pcf foam is conservatively used in this analysis.

The properties are documented in Table 3-8.

Table 3-8 Thermal Properties of 12-pcf Polyurethane Foam Temperature Density Thermal Conductivity Specific Heat

°F (°C) (lbm/ft3) (BTU*in/hr*ft2*°F) [W/(m*k)] (BTU/lbm*°F) 75 (24) 12.0 0.274 [0.04] 0.353

Reference:

Appendix 1.4.3: Thermal Conductivity.

[6] Density and Specific Heat: FR-3712 Rigid Polyurethane Foam (12 pcf).

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.2.1.6 Gasket Materials Gasket materials are not credited for thermal insulation and their properties are not explicitly modeled in this calculation. Because the gaskets will attain the temperature of the material around them, properties of the surrounding steel are used in this analysis.

3.2.1.7 Thermal Emissivity A painted surface is considered for NCT and pre-fire conditions. Fire and post-fire emissivity values are as provided in regulatory handbooks. All emissivity values and references are documented in Table 3-9.

Table 3-9 Thermal Emissivity Values HAC HAC Surface Condition Emissivity NCT (Fire) (Post Fire)

Painted surface 0.9 Painted Oxidized Fire Fire 0.9 surface Steel (0.9)

(0.9) (0.8)

Oxidized Steel 0.8

Reference:

[1] Emissivity HAC fire and post-fire, 10 CFR 71.73(c)(4)

[7] Emissivity of painted surface Black glass paint 3.2.2 Component Specifications The Versa-Pac is insulated to protect the containment boundary during Hypothetical Accident Conditions (HAC). The drum and the liner are separated by air gaps except at the locations of the vertical and horizontal stiffeners. The volume between the liner and the payload canister is filled with ceramic blanket insulation. A fiberglass thermal break is used to limit the flow of heat to the payload cavity through the steel flange components. The package containment is rated to an internal pressure of 15 psig. The relevant thermal material properties are provided in Section 3.2.1 above.

These insulators have been shown by the manufacturers to perform adequately over extended periods of time, with no shrinkage, settling, or loss of insulating properties. Additionally, these insulators do not burn. The melting point of the ceramic blanket insulation and the fiberglass thermal break are well above the temperature of the 1475°F (800°C) fire specified by 10 CFR 71.73. These insulation products are provided as fire-protection and are sacrificial components during a fire event. Steel components are serviceable to 800°F (427°C) per the ASME Code and have a melting point of about 2500°F (1371°C).

The payload cavity gaskets are rated for operating temperatures between -40°F (-40°C) and 1800°F (982°C); however, due to permeation in the silicone coating of the cavity seal, the maximum normal and HAC operating pressure are expected to be near atmospheric pressure during all conditions of transport.

The Versa-Pac design allows for the use of two neoprene pads: a 1/8-inch bottom pad, and a 3/8-inch top pad. The pads serve the purpose of protecting the inner containment shell during repeated use. As the use of these pads is optional, the neoprene material is not included in the thermal model. The flash point available in open literature for neoprene is approximately 500°F 3-9

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 (260°C). Since the internal temperature of the containment vessel has been shown not to exceed 400°F (204°C), the inclusion of neoprene does not increase the thermal load of the package.

Thermal design criteria are specified for separate regions throughout the Versa-Pac shipping package. Each region is limited to the temperature specified in Table 3-10. This table presents the maximum design temperatures of the components or materials that affect structural integrity, containment, and criticality control. Where available, temperature limits for the Versa-Pac components are obtained from manufacturers literature. Otherwise, the component temperature limits are defined as the melting temperature of the material of construction. NCT limits generally reflect the upper temperature limit listed for retention of structural integrity, continuous load ratings, or the maximum allowable temperature of the contents. HAC limits generally reflect melting temperatures, short-term (transient) material temperature limits, or the maximum allowable temperature of the contents.

Table 3-10 Temperature Limits NCT Temperature Limit HAC Temperature Limit Component or Material

°F (°C) °F (°C)

ASTM A-36 Carbon Steel ---a --- 2600 (1427) 525 Fiberglass b 150 (66) 1800 (982)

Cerablanket (6 pcf) 2150 (1177) 2400 (1316)

Polyurethane Foam (Containment insulation plug) 270 (132) 2000+c (1093)

High Temp., Heat Resistant, Silicone-Coated 500 (260) 1000 (538)

Fiberglass Gasket Inner Cavity - Standard and High-Capacity 600 d (316) 600 d (316)

Configurations Inner Cavity - 1S/2S UF6 Cylinder Configuration 250 (121) 250 (121)

Accessible Surfaces of Package 122 e (50) --- ---

References:

[8] 525 Fiberglass, Carbon steel melting temperature.

[4] Cerablanket: Continuous use and Classification temperature rating, Page 16.

[6] Polyurethane Foam NCT Temp. Limit: Glass Transition.

[2] 1S/2S Inner Cavity Limit: Table 1 of ANSI N14.1.

[1] Accessible Surfaces of Package: Non-exclusive use requirements per 10 CFR 71.43(g).

Notes:

a Carbon steel is not expected to have a significant loss of thermal properties during NCT.

b For NCT, 150°F is the temperature at which most FRPs begin to decompose. Some more specialized FRPs will begin decomposing at higher temperatures. For HAC, the reference states that, it is not uncommon for a fire retardant FRP product to be able to withstand a hydrocarbon fire at temperatures up to 1800°F for 30 minutes.

c In Reference [9], 2000+°F is the temperature at which the foams intumescent char will begin to decompose. This char, consisting of burned foam, serves as a secondary, insulating barrier for the remainder of the foam in a fire event.

d 600°F is the temperature limit specified for these configurations of the Versa-Pac.

e Based on 10 CFR 71.43(g) non-exclusive use limit, only applies for case in the shade (no solar insolation).

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.3 Thermal Evaluation for Normal Conditions of Transport (NCT)

The thermal performance of the Versa-Pac is analyzed for NCT by performing a steady-state heat transfer analysis on a finite element representation of the package. The general-purpose finite-element code ANSYS 19.1 is used to model and analyze the VP-55. In addition, supporting classical equations are documented in Appendix 3.5.5.

The bounding NCT case has a uniform heat flux is applied using steady state thermal analysis by exposing the package to a 38°C (100°F) ambient temperature and insolation as specified in Table 3-12. The results of the analysis are presented in Section 3.3.1, which includes the temperatures of the key package components.

Finite Element Model Because the VP-55 package is axially symmetrical, a quarter symmetry model of the package is used in this analysis. ANSYS Workbench is used to generate the Finite Element Model of the package. A combination of SOLID70, CONTA173, and TARGE170 element types are used to simulate the heat flow. Figure 3-2 shows the solid model, key components, and mesh.

The SOLID70 is a 3D, 8-node, single degree-of-freedom (DOF) thermal solid element. It is used to model heat flow through the solid and gaseous regions of the package via conduction heat transfer. Internal heat generation is applied to the SOLID70 elements of the interior air body and solar insolation and radiation are applied to the area faces of the exterior SOLID70 elements.

The CONTA173/TARGE170 pairs are 3D, 4-node, surface-to-surface contact elements that are overlaid onto area faces of the SOLID70 elements and are used to model heat flow across interfaces between contacting components or across interfaces between dissimilar meshes.

Bonded contact (perfect contact) is used to provide high thermal contact conductance.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Drum Lid (Part DL)

Polyurethane Foam Plug (Part IC)

Containment Lid (Part PD)

Air Gaps Containment Foam Plug (Part IG) 55 Gallon Drum (Part DA)

Ceramic Blanket (Part IA)

Cavity Air Containment End Plate (Part PB)

Polyurethane Foam Plug (Part ID)

Ceramic Paper (Part ID)

Figure 3-2 Quarter Symmetry Finite Element Model of the VP-55 Boundary Conditions The boundary conditions for all cases are listed in Table 3-11. Four NCT cases were analyzed simulating different combinations of ambient temperature, solar insolation, and internal heat generation to determine the bounding configuration. The four cases and their boundary conditions are also visualized in Figure 3-3 to Figure 3-6. The insolation modeled is per 10 CFR 71.71(c)(1) and is listed in Table 3-12.

Table 3-11 Summary of NCT Boundary Conditions Ambient Solar Internal Heat Case Temperature Convection Emissivity Insolation Generation

°F (°C)

Case I 100 (37.8) Yes Natural Surface Paint (0.9) 11.4 W Case II 100 (37.8) No Natural Surface Paint (0.9) 11.4 W Case III -40 (-40) No Natural Surface Paint (0.9) 11.4 W Case IV -40 (-40) No Natural Surface Paint (0.9) 0W 3-12

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 3-12 Insolation Data Total Insolation for a 12-hour Period Form and location of surface (g cal/cm2)

Flat surfaces transported Base None horizontally Other Surfaces 800 Flat surfaces not transported horizontally 200 Curved surfaces 400 3.3.1 Heat and Cold Regulations require testing the package for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of solar heating and 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of shade conditions during NCT. This requires a transient thermal analysis. However, it can be simplified by calculating a uniform heat flux and using steady state analysis. The heat flux is calculated by distributing the given 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> total insolation value over 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period as stated in Thermal modeling of packages for normal conditions of transport with insolation in para. 657.3 of SSR-6 [10]:

" #$% ' ' () 0*()

1 #&! = 41840 &! = 41840 *

&! *+,, -.#.

= 11.62 &!

1. $%& (**+

2,, 2,, 66.+3 2,,66.+3 0*() 0

= = = 387.41 34 () 34 () 34 ()*&! &!

4,, 4,,66.+3 0*() 0 34 ()

= 34 ()* &!

= 193.7 &!

3,, 3,,66.+3 0*() 0

= = 96.85 34 () 34 ()*&! &!

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Solar Insolation: Convection: Radiation:

W W Emissivity = 0.9 387.41 ! 5 !

m m * °C Solar Insolation:

W 193.7 !

m Convection: Internal Heat Generation:

W 5 ! Decay Heat = 170.24 W/m³ (11.4 W) m * °C Radiation:

Emissivity = 0.9 Adiabatic Bottom Ambient Temperature: 37.7°C Figure 3-3 NCT Boundary Conditions for CASE I (Hot: Internal wattage + Solar insolation) 3-14

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Solar Insolation: Convection: Radiation:

W W Emissivity = 0.9 0.0 ! 5 !

m m ' °C Solar Insolation:

W 0.0 !

m Convection: Internal Heat Generation:

W 5 ! Decay Heat = 170.24 W/m³ (11.4 W) m ' °C Radiation:

Emissivity = 0.9 Adiabatic Bottom Ambient Temperature: 37.7°C Figure 3-4 NCT Boundary Conditions for CASE II (Hot: Internal wattage + No solar insolation) 3-15

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Solar Insolation: Convection: Radiation:

W W Emissivity = 0.9 0.0 ! 5 !

m m ' °C Solar Insolation:

W 0.0 !

m Convection: Internal Heat Generation:

W 5 ! Decay Heat = 170.24 W/m³ (11.4 W) m ' °C Radiation:

Emissivity = 0.9 Adiabatic Bottom Ambient Temperature: -40 °C Figure 3-5 NCT Boundary Conditions for CASE III (Cold: Internal wattage + No Insolation) 3-16

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Solar Insolation: Convection: Radiation:

W W Emissivity = 0.9 0.0 ! 5 !

m m ' °C Solar Insolation:

W 0.0 !

m Convection: Internal Heat Generation:

W 5 ! Decay Heat = 0.0 W/m³ (0.0 W) m ' °C Radiation:

Emissivity = 0.9 Adiabatic Bottom Ambient Temperature: -40 °C Figure 3-6 NCT Boundary Conditions for CASE IV (Cold: No Internal wattage + No Insolation) 3-17

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.3.1.1 NCT Evaluation Results Results of the NCT evaluation show that a maximum exterior surface temperature in the shade (i.e. Case II) of 102°F (39°C) is observed on the drum. This meets the non-exclusive use shipment requirement of 10 CFR 71.43(g). The maximum interior air volume temperature is 232 °F (111°C).

NCT thermal evaluation temperature contour of the package for all cases are documented in Figure 3-7 to Figure 3-10. For select components, summary results of the NCT thermal evaluation for all cases are documented in Table 3-13. Temperature contours for Case I are shown in Figure 3-7, temperature contours for Case II are shown in Figure 3-8, temperature contours for Case III are shown in Figure 3-9, and temperature contours for Case IV are shown in Figure 3-10.

Table 3-13 NCT Steady State Thermal Evaluation Results Temperature °F (°C)

Hot Cold Component S.N.

Case I Case II Case III Case IV Max. Max. Max. Max. Min.

Containment body PA 147 (64) 113 (45) -27 -(33)

Containment end plate PB 147 (64) 114 (46) -26 -(32)

Containment insulation plug IG 177 (80) 139 (60) 0.5 -(18)

Gasket GB 143 (61) 104 (40) -35 -(37)

Containment lid (Blind flange) PD 143 (62) 104 (40) -35 -(37)

Drum lid DL 154 (68) 101 (39) -38 -(39) -40 (-40) -40 (-40)

Drum lid gasket GA 144 (62) 101 (39) -38 -(39)

Drum DA 144 (62) 102 (39) -38 -(39)

Package surface DA/DL 154 (68) 102 (39) -38 -(39)

Air Volume Ave N/A 191 (88) 158 (70) 23 (-5)

Air Volume Max N/A 232 (111) 201 (94) 73 (23) 3-18

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F Figure 3-7 NCT Temperature Contour-Case I (Hot: Internal wattage + Solar insolation)

Temperature °F Figure 3-8 NCT Temperature Contour-Case II (Hot: Internal Wattage + No Insolation) 3-19

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F Figure 3-9 NCT Temperature Contour-Case III (Cold: Internal Wattage + No Insolation)

Temperature °F Figure 3-10 NCT Temperature Contour-Case IV (Cold: No Internal Wattage + No Insolation) 3-20

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.3.2 Maximum Normal Operating Pressure Due to permeation in the silicone coating on the cavity seal, the maximum normal operating pressure is expected to be near atmospheric pressure. However, the maximum pressure increases from rising temperatures, considering the containment to be a perfectly sealed system, is approximately 3.3 psig (124 kPa) based on the average cavity NCT temperature of 191°F (88°C), recorded in Table 3-13.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.4 Thermal Evaluation for Hypothetical Accident Conditions (HAC)

A transient thermal analysis is performed on the VP-55 quarter model to simulate hypothetical accident fire conditions. This transient analysis simulates exposure of the package to a fully engulfed fire at 800°C for 30 minutes followed by a 7.5-hour cool down period, which is sufficient for package components to reach their maximum temperature.

The details of the HAC pre-fire, fire, and post-fire cool-down boundary conditions are documented in Sections 3.4.1 and 3.4.2 below. In addition, the supporting classical equations are documented in Appendix 3.5.4. The results of the HAC thermal evaluation are documented in Sections 3.4.3 and 3.4.4.

3.4.1 Initial Conditions The body temperature results of the NCT thermal analysis (hottest case: Case I) are used as the initial body temperature of the package for the HAC thermal analysis, see Figure 3-11. In addition, the ambient temperature before and after the fire is equal to 37.78°C (100°F) with insolation modeled as in Table 3-12.

Temperature °F Figure 3-11 NCT Results as Initial Conditions of HAC 3-22

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.4.2 Fire Test Conditions For the fire test, a transient thermal analysis is used. The modeled fire has an emissivity coefficient of 0.9 and a flame temperature of 800°C (1472°F). Forced convection film coefficients of 15.6 and 17.4 W/m²*°C are applied to the flat ends and cylindrical side surface, respectively.

As shown in Figure 3-12, HAC fire evaluation is conducted in a horizontal position for maximum fire exposure of the package.

Initial body temperature: NCT (Hot-Case I) results Environment fire temperature: 800°C Fire test position: Horizontal Internal Heat Generation:

Decay Heat = 170.24 W/m³ (11.4 W)

Convection:

Convection: Temperature = 800°C Temperature = 800°C Film Coefficient = 15.6 W/m²°C Film Coefficient = 15.6 W/m²°C Radiation:

Radiation: Temperature = 800°C Temperature = 800°C Emissivity = 0.9 Emissivity = 0.9 Convection: Radiation:

Temperature = 800°C Temperature = 800°C Film Coefficient = 17.4 W/m²°C Emissivity = 0.9 Figure 3-12 HAC Fire Boundary Conditions 3-23

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.4.2.1 Cool-Down (Post-Fire) Conditions At the end of the 30-minute fire, the environment temperature is dropped to 37.78°C (100°F).

Solar insolation is considered with the application of the NCT heat flux. Because the package is in a horizontal position during the fire, it stays in that position post fire. Therefore, both ends of the package are considered as vertical flat surfaces. Natural convection is also applied to the entire exterior surface with a convection coefficient of 5 W/m²*°C. Figure 3-13 shows the post fire boundary conditions.

Internal Heat Generation:

Decay Heat = 170.24 W/m³ (11.4 W)

Convection:

Convection: Temperature = 37.78°C Temperature = 37.78°C Film Coefficient = 5 W/m²°C Film Coefficient = 5 W/m²°C Radiation:

Radiation: Temperature = 37.78°C Temperature = 37.78°C Emissivity = 0.8 Emissivity = 0.8 Convection: Radiation:

Temperature = 37.78°C Temperature = 37.78°C Film Coefficient = 5 W/m²°C Emissivity = 0.8 Figure 3-13 HAC Cool-Down (Post-Fire) Boundary Conditions 3-24

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.4.3 Maximum Temperatures and Pressure The results of the HAC temperature evaluation are documented in a form of temperature-time history plots, temperature contours and tabulated values. Summary values for select components are documented in Table 3-14. The temperature-time history plots for selected parts are displayed in Figure 3-14 and Figure 3-15. Further, the temperature contours are shown Figure 3-16 and Figure 3-17.

As shown in Figure 3-16, the maximum temperature in the containment flange region is 434°F (223°C) and occurs at 1.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> during the post-fire cooldown. However, the containment cavity surface maximum temperature is 380°F (193°C), which is located at the top of the cavity adjacent to the containment plug (IG). As documented in Table 3-14, the average interior air temperature reaches 351°F (177°C). The containment region temperature-time history plot is displayed in Figure 3-15.

Due to permeation in the silicone coating of the cavity seal, the maximum normal operating pressure is expected to be near atmospheric pressure. However, the maximum pressure increase from rising temperatures, considering the containment to be a perfectly sealed system, is approximately 9.8 psig (154 kPa) based on the cavity surface HAC temperature of 425°F (219°C), recorded in Table 3-21. Additionally, it has been demonstrated that accounting for any thermal degradation of packaging materials could result in a marginal pressure increase, but not sufficient to exceed the 15 psig (205 kPa) cavity rating [11].

Table 3-14 HAC Transient Thermal Evaluation Summary Results Time at Max.

Component S.N. Max. Temp. °F (°C) Temp.

hr. (sec.)

Air volume max. --- 399 (204) 2.30 (8282)

Air volume average --- 351 (177) 2.30 (8282)

Containment plug bottom surface IG 380 (193) 1.40 (5042)

Containment cavity surface N/A 380 (193) 1.40 (5042)

Containment lid (Blind flange) PD 423 (217) 1.40 (5042)

Containment body PA 412 (211) 1.40 (5042)

Gasket GB 425 (219) 1.40 (5042)

Inner flange PH 434 (223) 1.40 (5042)

Drum lid DL 1457 (792) 0.5 (1802)

Drum DA 1461 (794) 0.5 (1802) 3-25

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Drum Drum lid Drum lid plug bottom surface Containment flange Gasket Containment body Containment plug bottom surface Containment end plate Air volume average 1600 1400 1200 1000 TEMPERATURE (°F) 800 600 400 200 0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 TIME (HRS)

Figure 3-14 VP-55 HAC Package Temperature-Time History Plot Containment flange (PH) Containment gasket (GB) Containment body (PA)

Containment lid (PD) Containment end plate (PB) Containment Inner Surface 500 450 400 350 300 TEMPERATURE (°F) 250 200 150 100 50 0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 TIME (HRS)

Figure 3-15 VP-55 HAC Containment Temperature-Time History Plot 3-26

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F a.) Package Maximum Temperature - 30 min Temperature °F b.) Containment Region Maximum Temperature - 1.4 hr Temperature °F c.) Inner Surface Maximum Temperature - 1.4 hr Figure 3-16 HAC Thermal Analysis Maximum Temperature Contours 3-27

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F a.) Package Maximum Temperature - 30 min Temperature °F b.) Containment Region Maximum Temperature - 2.3 hr Temperature °F c.) Inner Surface Maximum Temperature - 8.0 hr Figure 3-17 HAC Thermal Analysis Maximum Temperature Contours at Several Times 3-28

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.4.4 Maximum Thermal Stresses The performance of the Versa-Pac with respect to thermal stresses is demonstrated through a fire test performed for a similar package (see Reference [12]). The flexible construction of the connection between the payload cavity and the flange assures that thermal gradients do not impose excessive stress on the package joints.

3.4.5 Accident Conditions for Fissile Material Packages for Air Transport This section is not applicable. The criticality analysis for Versa-Pac packages transported by air assumes ejection of all contents from the packaging into a bounding configuration (see Section 6.7). Thus, no thermal testing/analyses are necessary for Versa-Pac shipments via air transport.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5 Appendix The following appendices are included with Section 3:

3.5.1: References 3.5.2: Thermal Analysis of 1S/2S UF6 Cylinders in the VP-55 3.5.3: Thermal Analysis of the VP-55 with no Containment Insulation Plug 3.5.4: Thermal Analysis of the VP-55 with High-Capacity Basket 3.5.5: Supporting Classical Equations 3-29

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.1 References

[1] U.S. Nuclear Regulatory Commission, "Code of Federal Reguations Title 10, Part 71-Packaging and Transportation of Radioactive Material," 10 CFR 71, 2017.

[2] American National Standards Institute, "American National Standard for Nuclear Materials -

Uranium Hexafluoride - Packagings for Transport," ANSI N14.1, Latest Revision.

[3] American Society of Mechanical Engineers, "ASME Boiler and Pressure Vessel Code-Materials,"

Section II-Part D-Properties (Customary), 2010.

[4] Morgan Advanced Materials, "Thermal Products from Morgan Advanced Materials Product Data Book," 2017.

[5] T. L. Bergman, A. S. Lavine, I. P. Frank and D. P. Dewitt, Fundamentals of Heat and Mass Transfer, 7 ed., Jefferson City: John Wiley & Sons, 2011.

[6] General Plastics Manufacturing Company, "Last-a-Foam FR-3712 Rigid Polyurethane Foam,"

2017.

[7] Mikron Instrument Company, Inc., "Table of Emissivity of Various Surfaces," 2017.

[8] Specialty Plastics, Inc., "Fiberglass Reinforced Plastic (FRP) Piping Systems: A Comparison to Traditional Metallic Materials," 1998.

[9] General Plastics Manufacturing Company, "Design Guide LAST-A-FOAM FR-3700 Crash &

Fire Protection of Radioactive Material Shipping Containers," 2012.

[10] Martin Marietta Systems, Inc., "Thermal Modeling of Packages for Normal Conditions of Transport with Insolation," CONF-951135-28, 1994.

[11] DAHER-TLI, "Evaluation of Thermal Degradation of Packaging Material in Versa-Pac," CN-13002-301, Rev.2, 2013.

[12] Daher-TLI, "Century Champion Type B Package Immersion Test as Analogue for the Versa-Pac Type A Package," TR-20000-130-001, Rev. 0, Fulton, MD, 2021.

[13] ANSYS, Inc, "ANSYS 19.1," 2019.

[14] Sealed Air, "Ethafoam Polyethylene Foam Products, Typical Physical Properties," 2014. [Online].

Available: https://sealedair.com/product-care/product-care-products/medium-and-high-density-foams.

[15] Almanza O., Rodriguez-Perez M. and Saja D.J., "Measurement of the Thermal Diffusivity and Specific Heat Capacity of Polyethylene Foams using the Transient Plane Source Technique,"

Polym Int 53:2038 - 2044, 2004.

[16] International Atomic Energy Agency, "IAEA Safety Standards: Advisory Material for the IAEA Regulations for the Safe Transport of Radioactive Material," Specific Safety Guide No. SSG-26, 2012.

[17] Rockwool, "Rockboard 40/60/80, Premium Multipurpose Board Insulation for Acoustic/Thermal Applications," Web, https://editserver.rockwool.lt/north-america/syssiteassets/o2-rockwool/

commerce-assets/roofs/commercial_rockboard_sell-sheet.pdf?_x=0057cae4-5c4b-4c51-ac40-9f4ce7856933, Accessed, May, 2021.

[18] Corzan Industries, "Corzan Ducting Systems," 2002.

[19] Corzan Industries, "Response to Technical Inquiry," 2021.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.2 Thermal Analysis of 1S/2S UF6 Cylinders in the VP-55 This appendix documents the thermal analysis necessary to allow for the shipment of 1S and 2S UF6 cylinders in the Versa-Pac, as shown in Figure 3-18 and Figure 3-19. The criterion for this analysis is the maximum allowable temperature of 250°F (121°C) for the 1S and 2S cylinders, as listed in Table 1 of ANSI N14.1 [2]. The Versa-Pac inner cavity maximum temperature, 380°F (193°C), as documented in Table 3-14 above, is too great to allow for the shipment of 1S or 2S cylinders. To address this high cavity temperature issue, this appendix analyzes the addition of a polyethylene foam liner to the inner surface of the inner cavity to reduce the amount of heat transferred to the inner cavity. To determine the correct foam thickness, a study is conducted by gradually increasing the thickness of the polyethylene foam to the interior surface of the inner cavity until the interior surface temperature drops to the allowable range. This appendix has determined that a thickness of 2 inches (5 cm) of polyethylene foam with a minimum density of 9 pcf is sufficient to reduce the maximum Versa-Pac inner-cavity temperature to 245°F (118°C) and volumetric average temperature of 221°F (105°C).

Figure 3-18 ANSI N14.1 1S Cylinder Figure 3-19 ANSI N14.1 2S Cylinder 3-31

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.2.1 Design Features and Boundary Conditions The Versa-Pac is modeled as described in Section 3 above. To accommodate the maximum temperature requirement of 250°F (121°C) for the 1S and 2S cylinders, a foam liner is used to reduce the heat that enters the inner cavity of the Versa-Pac. This foam has the properties as listed in Table 3-16.

The thermal response of the Versa-Pac 55 with foam liner for 1S and 2S UF6 cylinders is analyzed under both normal conditions of transport (NCT) and hypothetical accident conditions (HAC). As documented in Table 3-11, the NCT maximum heat input into the package occurs NCT Case I.

However, for the 1S/2S cylinder there is no internal heat generation. Thus, NCT Case V, as shown in Table 3-15 below, applies the maximum heat input into the package without internal heat generation. Therefore, HAC Case II is equivalent to the boundary condition presented in Section 3.4.2 without internal heat generation.

Table 3-15 Summary of Boundary Conditions Environment Solar Radiation Internal Heat Case Temperature Convection Insolation Emissivity Generation

°F (°C)

NCT Case V 100 (37.8) Yes Natural Surface Paint (0.9) 0W 1475 (800) No Forced Fire (0.9) 0W HAC Case II 100 (37.8) Yes Natural Steel Oxidized (0.8) 0W 3.5.2.2 Analysis Details The NCT evaluation of the Versa-Pac with 1S/2S UF6 cylinder contents was done with a steady-state, heat-transfer analysis using a finite-element model of the package. The finite-element code ANSYS 19.1 [13] was used to model and analyze the Versa-Pac under NCT. Upon completion of the NCT analysis, the resultant temperature distribution of the Versa-Pac was used as the initial conditions of the HAC analysis.

The HAC evaluation of the Versa-Pac with 1S/2S UF6 cylinder contents was performed with a transient heat-transfer analysis of the ANSYS model. The finite-element code ANSYS 19.1 [13]

was used to model and analyze the Versa-Pac under HAC. Damage from the mechanical tests was not simulated; however, local reductions in wall thickness were shown in the drop tests to be limited to the outer 1-3/16 of the package (see Table 2-6). Since this portion of the package quickly reaches the temperature of the fire, a local reduction is not expected to influence the temperature of the contents. Observation of the prototype fire test article after the drop test showed no rupture of the drum or inner support structure [12]. Therefore, the foam was not in direct contact with the flame and no charring or burning of the packaging foam will occurred.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.2.3 Material Properties Density and thermal conductivity values are obtained from the foam providers website [14]. The densities are from (1.5 - 9.0) pcf, and the thermal conductivity ranges from 0.43 to 0.49 BTU*in/(hr*ft²*°F). While the low-density foams (1.5 - 1.8 pcf) provide higher thermal conductivity, the medium to high density foams (2.2 - 9.0 pcf) provide low thermal conductivity. In addition, the high-density foams provide better compressive strength and tear resistance. Therefore, polyethylene foam with a minimum density of 9 pcf must be used as the inner liner in the Versa-Pac because of the lowest thermal conductivity among the different foam densities.

Specific heat values of various polyethylene foams are also documented in Table 2 of Measurement of the Thermal Diffusivity and Specific Heat Capacity of Polyethylene Foams Using the Transient Plane Source Technique [15]. These values vary from 2285.5 to 2924.5 J/(kg*K).

Because the foam with a small specific heat capacity requires a small amount of heat energy to raise its temperature, the smallest value, 2285.5 J/kg*K, is conservatively used in this analysis.

Table 3-16 Thermal Properties of Polyethylene Foam Temperature Density Thermal Conductivity Specific Heat

°F (°C) (lbm/ft3) (BTU*in/hr*ft2*°F) [W/(m*k)] J/(kg*K) 75 (24) 9.0 0.43 [0.036] 2285.5 - 2924.5

References:

[14] Density: Ethafoam 900, Typical Physical Properties Table.

[14] Thermal Conductivity: Ethafoam 900, Typical Physical Properties Table.

[15] Specific Heat: Table 2.

3.5.2.4 NCT Thermal Evaluation 3.5.2.4.1 NCT Thermal Analysis Details The thermal performance of the Versa-Pac with 1S/2S UF6 cylinders is analyzed for NCT by performing a steady-state heat transfer analysis on a finite element representation of the package.

The general-purpose finite-element code ANSYS 19.1 is used to model and analyze the VP-55.

A uniform heat flux is applied using steady state thermal analysis by exposing the package to a 37.8°C (100°F) ambient temperature and insolation as specified in Table 3-15. The results of the analysis are presented in Section 3.5.2.4.2, which includes the temperatures of the key package components.

Because the VP-55 is axially symmetrical, a quarter symmetry model of the package is used in this analysis. ANSYS Workbench is used to generate the Finite Element Model of the package.

A combination of SOLID70, CONTA173, TARGE170 element types are used to simulate the heat flow. Figure 3-20 shows the solid model, key components, and mesh.

The SOLID70 is a 3D, 8-node, single degree-of-freedom (DOF) thermal solid element. It is used to model heat flow through the solid and gaseous regions of the package via conduction heat transfer. Internal heat generation is applied to the SOLID70 elements of the interior air body and solar insolation and radiation are applied to the area faces of the exterior SOLID70 elements.

The CONTA173/TARGE170 pairs are 3D, 4-node, surface-to-surface contact elements that are overlaid onto area faces of the SOLID70 elements and are used to model heat flow across interfaces between contacting components or across interfaces between dissimilar meshes.

Bonded (perfect contact) is used to provide high thermal contact conductance.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Drum Lid (Part DL)

Polyurethane Foam Plug (Part IC)

Containment Gasket (Part GB)

Air Gaps Containment Lid (Part PD) 55 Gallon Drum (Part DA)

Ceramic Blanket (Part IA)

Polyethylene Foam Insert Containment End Plate (Part PB)

Polyurethane Foam Plug (Part ID)

Ceramic Paper (Part ID)

Figure 3-20 Quarter Symmetry Finite Element Model of The Versa-Pac To simulate NCT, the following boundary conditions were used for the NCT model:

1. Solar insolation according to 10 CFR 71.71(c)(1). The 12-hour solar insolation values are used to calculate a 24-hour steady state heat flux on the exterior surface of the package.

2. An ambient temperature of 37.78°C (100°F) with natural convection (5.0 W/m2*°C, para.

728.30 [16]) applied to the package exterior surfaces.

3. Thermal radiation Specific boundary condition values are displayed in Figure 3-21 below.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Solar Insolation: Convection: Radiation:

W W Emissivity = 0.9 387.41 ! 5 !

m m * °C Solar Insolation:

W 193.7 !

m Convection:

W Internal Heat Generation:

5 ! Heat Flux = 0 W/m² m * °C Radiation:

Emissivity = 0.9 Adiabatic Bottom Ambient Temperature: 37.78°C Figure 3-21 NCT Boundary Conditions 3-35

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.2.4.2 NCT Results Results of the NCT evaluation show that the maximum foam liner inner surface temperature is 138°F (59°C). The results for selected components are documented in Table 3-17 below and the overall body temperature is displayed in Figure 3-22 and Figure 3-23.

Table 3-17 NCT Steady State Results - 1S/2S UF6 Cylinder VP-55 Configuration Part Temperature Maximum Allowable Component Number °F (°C) Temperature °F (°C)

Containment body PA 139 (59) --

Containment end plate PB 134 (57) --

Containment insulation plug IG 139 (59) 270 (132)

Gasket GB 139 (59) 500 (260)

Containment lid (Blind flange) PD 139 (59) --

Drum lid DL 154 (68) --

Drum lid gasket GA 143 (62) --

Drum DA 143 (62) --

Package surface DA/DL 154 (68) --

Foam liner inner surface N/A 138 (59) 250 (121)

Note: See Table 3-10 for NCT temperature limits.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F Figure 3-22 NCT Evaluation Package Temperature Contour Temperature °F Figure 3-23 NCT Temperature Contour Showing Interior Surface of Foam Insert 3-37

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.2.5 HAC Thermal Evaluation The results of the NCT thermal analysis are used as the initial conditions for the HAC thermal analysis, see Figure 3-24. In addition, the ambient temperature before and after the fire is equal to 37.78°C (100°F) with insolation modeled as in Table 3-12.

Temperature °F Figure 3-24 HAC Fire Initial Body Temperature 3-38

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.2.5.1 Fire Test Conditions For the fire test, a transient thermal analysis is used. The modeled fire has an emissivity coefficient of 0.9, a flame temperature of 800°C (1472°F). Forced convection film coefficients of 15.6 and 17.4 W/m²*°C are applied to the flat ends and cylindrical side surface, respectively. As shown in Figure 3-25, the HAC fire evaluation is conducted in a horizontal position for maximum fire exposure of the package.

Initial body temperature: NCT results Environment fire temperature: 800°C Fire test position: Horizontal Internal Heat Generation:

Heat Flux = 0 W/m² Convection:

Convection: Temperature = 800°C Temperature = 800°C Film Coefficient = 15.6 W/m²°C Film Coefficient = 15.6 W/m²°C Radiation:

Radiation: Temperature = 800°C Temperature = 800°C Emissivity = 0.9 Emissivity = 0.9 Convection: Radiation:

Temperature = 800°C Temperature = 800°C Film Coefficient = 17.4 W/m²°C Emissivity = 0.9 Figure 3-25 HAC Fire Boundary Conditions 3-39

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.2.5.2 Cool-down (Post-fire) Conditions At the end of the 30-minute fire, the temperature is dropped to 37.78°C (100°F) and insolation is considered with the NCT heat flux values. Natural convection is also applied to the exterior surface with a convection coefficient of 5 W/m²*°C, see Figure 3-26.

Internal Heat Generation:

Heat Flux = 0 W/m² Convection:

Convection: Temperature: 37.78°C Temperature: 37.78°C Film Coefficient: 5 W/m²°C Film Coefficient: 5 W/m²°C Radiation:

Temperature = 37.78°C Radiation:

Emissivity = 0.8 Temperature = 37.78°C Emissivity = 0.8 Insolation:

Insolation: Heat Flux: 96.85 W/m² Heat Flux: 96.85 W/m² Convection: Radiation: Insolation Temperature: 37.78 °C Temperature: 37.78 °C Heat Flux: 193.7 W/m² Film Coefficient: 5 W/m²°C Emissivity = 0.8 Figure 3-26 HAC Post Fire Cool Down Boundary Conditions 3.5.2.5.3 HAC Results HAC requires determination of the minimum thickness sufficient to reduce the interior surface temperature to the acceptable range. Therefore, a study is conducted by gradually increasing the foam thickness to obtain the minimum thickness that can reduce the temperature of the inner cavity to the allowable limit.

The maximum allowable temperature for the shipment of 1S/2S UF6 cylinders is 250°F (121°C).

As shown in Figure 3-27 below, the foam thickness study predicts that 2-inch-thick foam is sufficient to reduce the cavity surface temperature to the acceptable range. Therefore, HAC analysis of the entire package is documented using the 2-inch-thick interior liner.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 2" Foam Liner Inner Surface 2" Foam liner body average 1" Foam Liner Inner Surface 350 300 250 TEMPERATURE (°F) 200 150 100 50 0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 TIME (HRS)

Figure 3-27 VP-55 1S/2S UF6 Cylinders - Containment Inner Surface Temp. with Foam Liners Maximum temperature values for selected components are documented in Table 3-18 below. In addition, the temperature-time histories of the package components are displayed in Figure 3-28 and Figure 3-29. The body temperature contour of the package is displayed in Figure 3-30 and Figure 3-31.

Table 3-18 HAC Fire Transient Results - 1S/2S UF6 Cylinder VP-55 Configuration Results Part Maximum Allowable Component Temperature Time Number Temperature °F (°C)

°F (°C) Hr. (Sec.)

Foam liner average N/A 221 (105) 4.10 (14761) 250 (121)

Foam liner inner surface maximum N/A 245 (118) 4.10 (14761) 250 (121)

Containment plug bottom surface IG 340 (171) 1.40 (5042) 2000 (1093)

Containment lid (Blind flange) PD 413 (212) 1.40 (5042) 2600 (1427)

Containment body PA 400 (204) 1.40 (5042) 2600 (1427)

Gasket GB 416 (213) 1.40 (5042) 1000 (538)

Inner flange PH 425 (219) 1.40 (5042) 2600 (1427)

Drum lid DL 1456 (791) 0.5 (1802) 2600 (1427)

Drum DA 1460 (793) 0.5 (1802) 2600 (1427) 3-41

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Foam liner inner surface Foam liner body average Drum Drum lid Drum lid plug bottom surface Inner flange Gasket Containment body Containment plug bottom surface Containment end plate 1600 1400 1200 1000 TEMPERATURE (°F) 800 600 400 200 0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 TIME (HRS)

Figure 3-28 VP-55 1S/2S UF6 Cylinders Entire Package HAC Temperature History Inner flange Gasket Containment body Containment lid Containment end plate Foam liner inner surface Foam liner body average 450 400 350 300 TEMPERATURE (° F) 250 200 150 100 50 0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 TIME (HRS)

Figure 3-29 VP-55 1S/2S UF6 Cylinders Package Containment HAC Temperature History 3-42

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F a.) Package Maximum Temperature - 30 min Temperature °F b.) Containment Region Maximum Temperature - 1.4 hr Temperature °F c.) Foam Liner Maximum Temperature - 1.4 hr Figure 3-30 HAC Thermal Analysis Maximum Temperature Contour 3-43

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F a.) Package Maximum Temperature - 30 min Temperature °F b.) Package Maximum Temperature - 4.1 hr Temperature °F c.) Package Maximum Temperature - 6.5 hr Figure 3-31 HAC Thermal Analysis Package Maximum Temperature Contour at Different Times 3-44

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.3 Thermal Analysis of the VP-55 with no Containment Insulation Plug This appendix documents the thermal analysis of the 55-gallon Versa Pac (VP-55) with the containment insulation foam plug Part (IG) removed. The containment insulation foam plug (IG) is removed to accommodate higher volumes of non-heat generating low-density materials to be filled directly into the VP-55 inner cavity. Because the foam plug is removed, this thermal analysis shows that containment temperatures remain within the thermal limits of the contents.

Drum Lid (Part DL)

Polyurethane Foam Plug (Part IC)

Containment Gasket (Part GB)

Air Gaps Containment Lid (Part PD) 55 Gallon Drum (Part DA)

Ceramic Blanket (Part IA)

Containment Body (Part PA)

Containment End Plate (Part PB)

Polyurethane Foam Plug (Part ID)

Ceramic Paper (Part ID)

Figure 3-32 VP-55 Without Containment Insulation Plug (Part IG) 3-45

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.3.1 Design Features and Boundary Conditions The thermal response of the Versa-Pac 55 without the containment insulation plug is analyzed under both normal conditions of transport (NCT) and hypothetical accident conditions (HAC). As documented in Table 3-11, the NCT maximum heat input is the same as NCT Case I. Therefore, NCT Case I, as shown in Table 3-19 below, applies the maximum heat input into the package with internal heat generation applied as a surface heat flux. Similarly, HAC Case I is equivalent to the boundary condition presented in Section 3.4.2.

Table 3-19 Summary of Boundary Conditions Environment Solar Radiation Internal Heat Case Temperature Convection Insolation Emissivity Generation

°F (°C)

NCT Case I 100 (37.8) Yes Natural Surface Paint (0.9) 11.4 W 1475 (800) No Forced Fire (0.9) 11.4 W HAC Case I 100 (37.8) Yes Natural Steel Oxidized (0.8) 11.4 W 3.5.3.2 Analysis Details The Versa-Pac is modeled as described in Section 3 above except the containment insulation plug Part (IG) is removed in this model.

The NCT evaluation of the Versa-Pac, without the containment insulation plug, was performed with a steady-state, heat-transfer analysis using a finite-element model of the package. The finite-element code ANSYS 19.1 [13] was used to model and analyze the Versa-Pac under NCT. Upon completion of the NCT analysis, the resultant temperature distribution of the Versa-Pac was used as the initial conditions of the HAC analysis.

The HAC evaluation of the Versa-Pac, without the containment insulation plug, was performed with a transient heat-transfer analysis using the finite element model. Damage from the mechanical tests was not simulated; however, local reductions in wall thickness were shown in the drop tests to be limited to the outer 1-3/16 of the package (See Table 2-6). Since this portion of the package quickly attains the temperature of the fire, a local reduction is not expected to influence the temperature of the contents. Further, observation of the test article after the drop test showed no rupture of the drum or inner support structure, hence no charring or burning of the packaging foam will occur under HAC (Appendix 2.13.7).

3.5.3.3 Material Properties and Component Specifications Material properties and component specifications are as documented in Section 3.2.

3-46

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.3.4 NCT Thermal Evaluation 3.5.3.4.1 NCT Thermal Analysis Details The thermal performance of the Versa-Pac, without containment insulation plug, is analyzed for NCT by performing a steady-state heat transfer analysis on a finite element representation of the package. The finite-element code ANSYS Workbench 19.1 [13] is used to generate the model and perform the analyses. Because the Versa-Pac is axisymmetric, a quarter symmetry model of the package is used for this evaluation. A combination of SOLID90, CONTA173, TARGE170 element types are used to simulate the heat flow. The SOLID90 is a 3D, 8-node, single degree-of-freedom (DOF) thermal solid element. It is used to model heat flow through the solid and gaseous regions of the package via conduction heat transfer. ANSYS CONTA173/TARGE170 pairs are 3D, 4-node, surface-to-surface contact elements that are overlaid onto area faces of the SOLID90 elements and are used to model heat flow across interfaces between contacting components or across interfaces between dissimilar meshes. Bonded (perfect contact) is used to provide high thermal contact conductance.

Figure 3-33 Finite Element Model of The Versa Pack Quarter Symmetry Model 3-47

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 To simulate NCT, the following boundary conditions were used for the NCT model:

1. Solar insolation according to 10 CFR 71.71(c)(1). The 12-hour solar insolation values are used to calculate a 24-hour steady state heat flux on the exterior surface of the package.

2. An ambient temperature of 37.78°C (100°F) with natural convection (5.0 W/m2*°C, para.

728.30 [16]) applied to the package exterior surfaces.

3. Thermal radiation Specific boundary condition values are displayed in Figure 3-34 below.

Figure 3-34 NCT Boundary Conditions 3-48

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.3.4.2 NCT Results Results of the NCT evaluation show that the maximum overall temperature of 154°F (68°C) and interior cavity temperature is 147°F (64°C). The results for selected components are documented in Table 3-20 below and the overall body temperature is displayed in Figure 3-35, and the interior surface temperature is displayed in Figure 3-36.

Table 3-20 NCT Steady State Thermal Evaluation Results -VP-55 Configuration Without Containment Insulation Plug Part Temperature Maximum Allowable Component Number °F (°C) Temperature °F (°C)

Containment body PA 147 (64)

Containment end plate PB 147 (64)

Gasket GB 143 (62) 500 (260)

Containment lid (Blind flange) PD 143 (62) 600 (260)

Drum lid DL 154 (68)

Drum lid gasket GA 145 (63)

Drum DA 144 (62)

Package Surface DA/DL 154 (68)

Containment Inner Surface N/A 147 (64) 600 (316)

Note: See Table 3-10 for NCT temperature limits.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F Figure 3-35 NCT Evaluation Package Temperature Contour Temperature °F Figure 3-36 NCT Temperature Contour Interior Surface 3-50

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.3.5 HAC Thermal Evaluation The results of the NCT thermal analysis are used as the initial conditions for the HAC thermal analysis, see Figure 3-35. In addition, the ambient temperature before and after the fire is equal to 37.78°C (100°F) with insolation modeled as in Table 3-12.

3.5.3.5.1 Fire Test Conditions For the fire test, a transient thermal analysis is used. The fire is modeled with an emissivity of 0.9 and a flame temperature of 800°C (1472°F). Forced convection film coefficients of 15.6 and 17.4 W/m²*°C are applied to the flat ends and cylindrical side surface, respectively. As shown in Figure 3-37, the HAC fire evaluation is conducted in a horizontal position for maximum fire exposure of the package.

Initial temperature: NCT steady-state results Environment fire temperature: 800°C Fire test position: Horizontal Internal Heat Generation:

Heat Flux = 11.3 W/m² Convection:

Convection:

Temperature = 800°C Temperature = 800°C Film Coefficient = 15.6 W/m²°C Film Coefficient = 15.6 W/m²°C Radiation:

Radiation:

Temperature = 800°C Temperature = 800°C Emissivity = 0.9 Emissivity = 0.9 Convection: Radiation:

Temperature = 800°C Temperature = 800°C Film Coefficient = 17.4 W/m²°C Emissivity = 0.9 Figure 3-37 HAC Fire Boundary Conditions 3-51

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.3.5.2 Cool-down (Post-fire) Conditions At the end of the 30-minute fire, the temperature is dropped to 100°F (37.78°C) and insolation is considered with the NCT heat flux values. Natural convection is also applied to the exterior surface with a convection coefficient of 5 W/m²*°C, see Figure 3-38.

Internal Heat Generation:

Heat Flux = 11.3 W/m² Convection:

Convection: Temperature: 37.78°C Temperature: 37.78°C Film Coefficient: 5 W/m²°C Film Coefficient: 5 W/m²°C Radiation:

Temperature = 37.78°C Radiation:

Emissivity = 0.8 Temperature = 37.78°C Emissivity = 0.8 Insolation:

Insolation: Heat Flux: 96.85 W/m² Heat Flux: 96.85 W/m² Convection: Radiation: Insolation Temperature: 37.78 °C Temperature: 37.78 °C Heat Flux: 193.7 W/m² Film Coefficient: 5 W/m²°C Emissivity = 0.8 Figure 3-38 HAC Post Fire Cool Down Boundary Conditions 3-52

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.3.5.3 HAC Results The HAC results for the VP-55 without containment insulating plug is provide in Table 3-21.

Temperature-time history plots for select components of entire package and containment region are displayed in Figure 3-39 and Figure 3-40, respectively. Temperature contour plots are shown in Figure 3-41 and 3-42.

As shown in Figure 3-40, the maximum temperature in the containment region of 445°F (229°C) was recorded at 1.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. However, package component temperatures remain below the maximum allowable temperatures.

Table 3-21 HAC Transient Thermal Evaluation Results - VP-55 Configuration Without Containment Insulation Plug Results Maximum Part Component Temperature Time Allowable Number

°F (°C) Hr. (Sec.) Temperature °F (°C)

Containment cavity surface N/A 425 (218) 1.40 (5042) 600 (316)

Containment lid (Blind flange) PD 433 (223) 1.40 (5042) 2600 (1427)

Containment body PA 423 (217) 1.40 (5042) 2600 (1427)

Gasket GB 436 (224) 1.40 (5042) 1000 (538)

Inner flange PH 445 (229) 1.40 (5042) 2600 (1427)

Drum lid DL 1456 (791) 0.5 (1802) 2600 (1427)

Drum DA 1460 (793) 0.5 (1802) 2600 (1427)

Note: See Table 3-10 for HAC temperature limits.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Drum Drum lid Drum lid plug bottom surface Inner flange Gasket Containment body Containment end plate Containment inner surface 1600 1400 1200 1000 TEMPERATURE (°F) 800 600 400 200 0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 TIME (HRS)

Figure 3-39 VP-55 Entire Package HAC Temperature History (Without Containment Insulation Plug) Maximum Temperature History Inner flange Gasket Containment body Containment lid Containment end plate Containment inner surface 500 450 400 350 300 TEMPERATURE (°F) 250 200 150 100 50 0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 TIME (HRS)

Figure 3-40 VP-55 (Without Containment Insulation Plug) Containment Temperature History 3-54

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F a.) Package Maximum Temperature - 30 min Temperature °F b.) Containment Region Maximum Temperature - 1.4 hr Temperature °F c.) Containment Interior Surface Maximum Temperature - 1.4 hr Figure 3-41 HAC Thermal Analysis Containment Maximum Temperature Contours 3-55

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F a.) Package Maximum Temperature - 30 min Temperature °F b.) Containment Region Maximum Temperature - 2.5 hr Temperature °F c.) Containment Interior Surface Maximum Temperature - 6.5 hr Figure 3-42 HAC Thermal Analysis Package Maximum Temperature Contour During Fire and Cool Down 3-56

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.4 Thermal Analysis of the VP-55 with High-Capacity Basket This appendix documents the thermal analysis of the 55-gallon Versa Pac with High-Capacity Basket (HCB). The HCB is built using aluminum plates, Rockwool Rockboard insulation material and CPVC isolation pipes and separator plate. Because the HCB incorporates CPVC for neutron moderation, supplementary thermal analysis is documented in this appendix to ensure the CPVC material remains within its thermal limits during NCT and HAC. Figure 3-43 shows the ANSYS Workbench solid and finite element models.

Drum Lid (Part DL)

Polyurethane Foam Plug (Part IC)

Containment Lid (Part PD)

Containment Gasket (Part GB)

Air Gaps Basket Disk (Part TD)

Insulating Disk (Part RW) 55 Gallon Drum (Part DA)

Ceramic Blanket (Part IA)

Basket Disk (Part SD)

Separator Plate (Part MC)

Isolation Pipe (Part MP)

Containment End Plate (Part PB)

Polyurethane Foam Plug (Part ID)

Ceramic Paper (Part ID)

Figure 3-43 VP-55 with High-Capacity Basket (HCB) 3.5.4.1 Boundary Conditions The thermal response of the Versa-Pac 55 with the HCB is analyzed under both normal conditions of transport (NCT) and hypothetical accident conditions (HAC). Table 3-22 provides a summary of the applied boundary conditions.

Table 3-22 Summary of Boundary Conditions Environment Conditions Temperature Solar Insolation Convection Radiation Emissivity

°F (°C)

NCT Case V 100 (37.8) Yes Natural Surface Paint (0.9) 1475 (800) No Forced Fire (0.9)

HAC Case II 100 (37.8) Yes Natural Steel Oxidized (0.8) 3-57

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.4.2 Design Features and Analysis Details The Versa-Pac base model is described in Section 3 above. The HCB is added to provide neutron moderation using CPVC isolation pipes creating two silos with an additional separating plate between the silos. The CPVC is supported by aluminum support disks joined together by stiffener arms and tie rods. Thermal protection for the CPVC is provided by Rockwool Rockboard, which maintains temperatures below thermal limits.

Because the VP-55 package is axis-symmetric, a quarter symmetry model of the package is used.

ANSYS Workbench is used to generate the Finite Element Model of the package with a combination of SOLID90, CONTA173, TARGE170 and SURF152 element types to simulate the heat flow.

The SOLID90 is a 3D, 8-node, single degree-of-freedom (DOF) thermal solid element. It is used to model heat flow through the solid and gaseous regions of the package via conduction heat transfer. Solar insolation, convection and radiation boundary conditions are applied to the SURF152 3D thermal surface effect elements overlaid onto area faces of the exterior SOLID90 elements.

The CONTA173/TARGE170 pairs are 3D, 4-node, surface-to-surface contact elements that are overlaid onto area faces of the SOLID90 elements and are used to model heat flow across interfaces between contacting components or across interfaces between dissimilar meshes.

Bonded (perfect contact) is used to provide high thermal contact conductance.

3.5.4.3 Material Properties and Component Specifications Material properties specific to the HCB are documented in this section.

3.5.4.3.1 Rockwool RockBoard Rockwool is used to provide thermal insulation for the HCB. The properties are documented in Table 3-23.

Table 3-23 Thermal Properties of Rockboard 60 Temperature Density Thermal Conductivity Specific Heat Temperature Limit

°F (°C) lbm/ft³ BTU*in/hr*ft2*°F [W/(m*k)] BTU/lbm*°F °F (°C) 75 (24) 6.0 0.236 [0.034] 0.20 482 (250)

Reference:

[17] Thermal Properties: Rockwool stone wool thermal and fire safe insulation 3.5.4.3.2 Thermal Properties of CPVC CPVC pipes and sheet are components of the HCB. The properties are documented in Table 3-24.

Table 3-24 Thermal Properties of CPVC Temperature Density Thermal Conductivity Specific Heat Temperature Limit °F (°C)

°F (°C) lbm/ft3 [g/cc] BTU*in/hr*ft2*°F [W/(m*k)] BTU/lbm*°F Pipe Grade Sheet Grade 73 (23) 96.8 [1.55] 0.95 [0.137] 0.21 248-291 241-248 b

212 (100) --- --- 0.26 (120-144) (116-120)

Reference:

[18] CPVC thermal properties

[19] Temperature limit (glass transition temperature) 3-58

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.4.3.3 Thermal Properties of Aluminum Alloy (6061)

Aluminum plates provide structural support for the HCB. The properties are documented in Table 3-25.

Table 3-25 Thermal Properties of Aluminum Alloy (6061)

Temperature Density Thermal Conductivity (TC) Thermal Diffusivity Specific Heat a

°F (°C) lbm/ft³ BTU*ft/hr*ft2*°F [W/(m*k)] ft2/hr BTU/lbm*°F 70 (21) 169.3 96.1 [166.3] 2.661 0.213 200 (392) --- 99.0 [171.3] 2.649 0.221 300 (572) --- 100.6 [174.1] 2.629 0.226

Reference:

[3] Density: (Table PRD, A96061, Page 744.), Thermal Conductivity, Thermal diffusivity & Specific heat (Table TCD, A96061, Page 735).

3.5.4.3.4 Thermal Properties of Stainless Steel (304)

Stainless steel fasteners are used to assemble the HCB. The properties are documented in Table 3-26.

Table 3-26 Stainless Steel (304) Properties Temperature Density Thermal Conductivity Thermal Diffusivity Specific Heat

°F (°C) lbm/ft³ BTU*ft/hr*ft2*°F [W/(m*k)] ft2/hr BTU/lbm*°F 70 (21) 501.1 8.6 [14.9] 0.151 0.114

Reference:

[3] Density: (Table PRD, High alloy steels (300 series), Page 744.), Thermal Conductivity, Thermal diffusivity & Specific heat (Table TCD, High Alloy Steels, Material Grp. J, Page 727).

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.4.4 NCT Thermal Evaluation 3.5.4.4.1 NCT Thermal Analysis Details The thermal performance of the VP-55 with HCB is analyzed for NCT by performing a steady-state heat transfer analysis on a finite element representation of the package. The general-purpose finite-element code ANSYS Workbench 19.1 [13] is used to model and analyze the VP-55 with HCB. A uniform heat flux is applied using steady state thermal analysis by exposing the package to a 37.8°C (100°F) ambient temperature and insolation as specified in Table 3-22. To simulate NCT, the following boundary conditions were used for the NCT model:

1. Solar insolation according to 10 CFR 71.71(c)(1). The 12-hour solar insolation values are used to calculate a 24-hour steady state heat flux on the exterior surface of the package.

2. An ambient temperature of 37.8°C (100°F) with natural convection (5.0 W/m²*°C, para.

728.30 [16]) applied to the package exterior surfaces.

3. Thermal radiation.

Specific NCT boundary condition values are displayed in Figure 3-44 below.

Solar Insolation: Convection: Radiation:

W W Emissivity = 0.9 387.41 ! 5 !

m m * °C Solar Insolation:

W 193.7 !

m Convection:

W Internal Heat Generation:

5 ! Heat Flux = 0 W/m² m * °C Radiation:

Emissivity = 0.9 Adiabatic Bottom Figure 3-44 NCT Boundary Conditions 3-60

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.4.4.2 NCT Evaluation Results Results of the NCT evaluation show that the maximum overall temperature of 154°F (68°C) and interior cavity temperature is 138°F (59°C). Further, the HCB CPVC Pipe maximum temperature is 136°F (58°C). The results for selected components are documented in Table 3-27 below and the overall body temperature is displayed in Figure 3-45 and Figure 3-46.

Table 3-27 NCT Steady State Thermal Evaluation Results Max. Temp.

Component S.N.

°F (°C)

Containment body PA 138 (59)

Containment end plate PB 134 (57)

Containment insulation plug IG 139 (59)

Gasket GB 139 (59)

Containment lid (Blind flange) PD 139 (59)

Drum lid DL 154 (68)

Drum lid gasket GA 143 (62)

Drum DA 143 (62)

Package Surface DA/DL 154 (68)

Containment inner surface --- 138 (59)

HCB CPVC Plate Maximum MC 135 (57)

HCB CPVC Pipe Maximum MP 136 (58)

HCB CPVC Pipe Average MP 135 (57) 3-61

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F Figure 3-45 NCT Evaluation Package Temperature Contour Temperature °F Figure 3-46 NCT Evaluation HCB Temperature Contour 3-62

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.4.5 Thermal Evaluation under Hypothetical Accident Conditions 3.5.4.5.1 Initial Conditions The results of the NCT thermal analysis are used as the initial conditions for the HAC thermal analysis. In addition, the ambient temperature before and after the fire is equal to 37.8°C (100°F) with insolation modeled as in Table 3-12.

3.5.4.5.2 Fire Test Conditions For the fire test, a transient thermal analysis is used. The modeled fire has an emissivity coefficient of 0.9 and a flame temperature of 800°C (1475°F). Forced convection film coefficients of 15.6 and 17.4 W/m²*°C are applied to the flat ends and cylindrical side surface, respectively.

As shown in Figure 3-47, HAC fire evaluation is conducted in a horizontal position for maximum fire exposure of the package. To simulate the side contact of the HCB and inner shell of the Versa-Pac, the air gap is replaced with carbon steel properties over a 30° contact angle.

Internal Heat Generation:

Heat Flux = 0 W/m² Convection:

Convection:

Temperature = 800°C Temperature = 800°C Film Coefficient = 15.6 W/m²°C Film Coefficient = 15.6 W/m²°C Radiation:

Radiation:

Temperature = 800°C Temperature = 800°C Emissivity = 0.9 Emissivity = 0.9 Convection: Radiation:

Temperature = 800°C Temperature = 800°C Film Coefficient = 17.4 W/m²°C Emissivity = 0.9 Figure 3-47 HAC Fire Boundary Conditions 3.5.4.5.3 Cool-Down (Post-Fire) Conditions At the end of the 30-minute fire, the ambient temperature returns to 100°F (37.8°C) and insolation is applied with the NCT heat flux values. Natural convection is also applied to the exterior surface with a convection coefficient of 5 W/m*°C. Figure 3-48 summarizes the post-fire, cool-down boundary conditions.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Internal Heat Generation:

Heat Flux = 0 W/m² Convection:

Convection: Temperature: 37.78°C Temperature: 37.78°C Film Coefficient: 5 W/m²°C Film Coefficient: 5 W/m²°C Radiation:

Radiation: Temperature = 37.78°C Emissivity = 0.8 Temperature = 37.78°C Emissivity = 0.8 Insolation:

Insolation: Heat Flux: 96.85 W/m² Heat Flux: 96.85 W/m² Convection: Radiation: Insolation Temperature: 37.78 °C Temperature: 37.78 °C Heat Flux: 193.7 W/m² Film Coefficient: 5 W/m²°C Emissivity = 0.8 Figure 3-48 HAC Post Fire Cool Down Boundary Conditions 3.5.4.5.4 HAC Thermal Evaluation Results Maximum HAC temperature values for selected components are documented in Table 3-28 below. In addition, the temperature time-histories of the package components are displayed in Figure 3-49 and Figure 3-50 and the body temperature contour of the package is displayed in Figure 3-51 and Figure 3-52. The maximum and average CPVC pipe temperatures are 240°F (116°C) and 190°F (88°C), respectively. The results show that the CPVC components remain below the maximum allowable temperature.

Table 3-28 HAC Transient Thermal Evaluation Summary Results Time at Max.

Max. Temp.

Component S.N. Temp.

°F (°C)

Hr (sec)¹ HCB CPVC Pipe Average MP 190 (88) 6.74 (24264)

HCB CPVC Pipe Maximum MP 240 (116) 3.20 (11521)

HCP CPVC plate Maximum MC 231 (111) 3.20 (11521)

Rockboard 60 Average RW 204 (96) 5.14 (18504)

Containment plug bottom surface IG 345 (174) 1.40 (5042)

Containment lid (Blind flange) PD 421 (216) 1.40 (5042)

Containment body PA 407 (209) 1.40 (5042)

Gasket GB 423 (217) 1.40 (5042)

Inner flange PH 433 (223) 1.40 (5042)

Drum lid DL 1456 (791) 0.5 (1802)

Drum DA 1460 (793) 0.5 (1802)

Notes:

¹Time in seconds corresponds to the time in the output file.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Drum Drum lid Drum lid plug bottom surface Inner flange Gasket Containment body Containment plug bottom surface Containment end plate HCB Pipe Average 1600 1400 1200 1000 TEMPERATURE (°F) 800 600 400 200 0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 TIME (HRS)

Figure 3-49 VP-55-HCB Entire Package Maximum Temperature History Inner flange Gasket HCB Pipe Maximum Containment lid Containment end plate HCB Pipe Average Containment Plug Bottom Surface (IG) Containment body 500 450 400 350 300 TEMPERATURE (°F) 250 200 150 100 50 0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 TIME (HRS)

Figure 3-50 VP-55 Package with HCB Temperature History 3-65

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F a.) Package Maximum Temperature - 30 min Temperature °F b.) Containment Region Maximum Temperature - 1.4 hr Temperature °F c.) HCB Maximum Temperature - 3.2 hr Figure 3-51 HAC Thermal Analysis Maximum Temperature Contour (a-c) 3-66

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Temperature °F a.) Package Maximum Temperature - 30 min Temperature °F b.) HCB Rockboard 60 Temperature - 3.2 hr Temperature °F c.) HCB CPVC Temperature - 3.2 hr Figure 3-52 HAC Thermal Analysis Package Maximum Temperature Contour at Different Times (a-c) 3-67

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.5 Supporting Classical Equations 3.5.5.1 Natural Convection The natural convection occurs on the still fluids on the exterior surface of the Versa-Pac and it is calculated with the following equation (Equation 6.4, Page 380 [5]):

qc = h0 (Ts - T) where, qc = convective heat flux (W/m2) h0 = convection heat transfer coefficient (W/m2*°C)

Ts = temperature of surface (°C)

T = temperature of environment (°C)

A heat transfer coefficient of 5 W/m²-°C is used for boundary conditions concerning natural convection. Additionally, this heat transfer coefficient can be defined with the following equations (Equation 9.24, Page 604 [5]):

789 h0 =

where, Nu- =

1. 1. 1. 1. 1. Nusselt Number L = characteristic length k = conduction heat transfer coefficient Depending on the orientation of the surface of concern, the Nusselt number will vary. The following equations give the Nusselt number for various geometries.

3.5.5.1.1 Vertical Plate The Nusselt number can be calculated for the entire range of Rayleigh number (Ra) by the following correlation (Equation 9.26, Page 605 [5]):

3

,.*2< =$, /

00000 Nu; = 0.825 + 5 3 !6

>6? @

0.23! ./

A B 4+

where, Ra; = Rayleigh number Pr = Prandtl number An improved accuracy of the Nusselt number can be obtained for laminar flow with the following equation for RaL (Equation 9.27, Page 605):

00000 0.670 78! 1/4 Nu; = 0.68 + 4 for Ra- 10A 9 9 91+ :0.492/;16 ?

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.5.1.2 Horizontal Plate The Nusselt number calculated for a horizontal plate is as follows (Equations 9.30 - 9.32, Page 610 [5]):

Upper Surface of Hot Plate or Lower Surface of Cold Plate 00000 Nu; = 0.54 Ra1/4 104 Ra 107, Pr 0.7 00000 Nu; = 0.15 Ra1/3 107 Ra 1011, all Pr Lower Surface of Hot Plate or Upper Surface of Cold Plate 00000 Nu; = 0.52 Ra1/5 104 Ra 109, Pr 0.7 The above Horizontal Plate correlations are used when the characteristic length is to be defined as (Equation 9.29, Page 609 [5]):

L = As/P where, As = surface area P = perimeter The Rayleigh number to be used to calculate the Nusselt number values is formulated as (Equation 9.25, Page 605 [5]):

" L (NB ONC ) ;D RaL = QR where, g = gravity (9.81 m/s2) b = 1 / (Tf + 459.67)

Tf = film temperature Ts = surface temperature T = ambient temperature L = characteristic length n = air kinematic viscosity at Tf

= air thermal diffusivity at Tf Note that the film temperature is the average temperature between the surface temperature and ambient temperature, Tf = (Ts + T)/2, and all properties are obtained at this temperature.

3.5.5.2 Forced Convection During the HAC 30-minute fire, forced convection film coefficient (hc) are applied as boundary conditions to each external surface of the package. Temperature dependent hc values are calculated for the range from ambient, 100°F (37.78°C), to the fire the temperature of 1472°F (800°C) based on the geometry of the surface [5]. The maximum calculated hc values for the range are conservatively applied to the external surfaces of the ANSYS model.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 The forced convection coefficient is calculated using the following equation (Equation 9.24 [5]):

89 x 7 h# =  ;

where, Nu = Nusselt number, k = thermal conductivity of air at the film temperature, and L = characteristic length of the surface = .571 m.

The Nusselt number (Nu) is a function of the Reynolds number (Re) and the Prandtl number. The Reynolds number is, in turn, a function of surface geometry, temperature, flow velocity, and properties (density and viscosity) of the surrounding air, which is calculated using the following equation (Equation 6.45 [5]):

VL Re =

where, V = air free-stream velocity = 10 m/s (Reference [16], §728.30),

L = characteristic length = .571 m, n = air dynamic viscosity at Tf, Tf = film temperature = (Ts + T¥)/2, Ts = surface temperature, and T¥ = ambient temperature.

The VP-55 package surfaces are modeled using Nu correlations for a cylinder in cross flow or a flat plate with parallel flow depending on which surface and package orientation being evaluated.

These Nu correlations are giving in the following section.

3.5.5.2.1 Cylinder in Cross Flow The characteristic length, L, of a cylinder is its diameter, D. The Nusselt number for a cylinder in cross flow is calculated using the following equation (Equation 7.55b [5]):

Nu= C ReD m Pr1/3 where, ReD = Reynolds number, and Pr = Prandtl number.

The constants C and m in the previous equation are functions of the Reynolds number (ReD) and are listed in Table 3-29.

Table 3-29 Constants 'C' and 'm' for the Nusselt Number Calculation of a Cylinder in Cross Flow ReD C m 0.4 - 4 0.989 0.330 4 - 40 0.911 0.385 40 - 4,000 0.683 0.466 4,000 - 40,000 0.193 0.618 40,000 - 400,000 0.027 0.805

Reference:

[5] Table 7.2.

3-70

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.5.2.2 Flat Plate with Parallel Flow For laminar flow (ReL 5x105 per Equation 6.24, [5]), the Nusselt number for external flow over a flat plate is calculated using the following equation (Equation 7.31, [5]):

Nu=0.664 ReL 1/2 Pr1/3 (5x105 ReL, Pr 0.6) where, ReL = Reynolds number, and Pr = Prandtl number.

For mixed parallel flow (laminar and turbulent), the Nusselt number for external flow over a flat plate is calculated using the following equation (Equation 7.44, [5]):

Nu=0.037 ReL 4/5 Pr1/3 (5x105 < ReL 108) where, ReL = Reynolds number, and Pr = Prandtl number.

To provide maximum heat input from the fire, the package is assumed to be laying in the horizontal position. Using the equations presented above, calculated forced convection film coefficients of 15.6 and 17.4 W/m²*°C are applied to the flat ends and cylindrical side surface of the package, respectively.

3.5.5.3 Radiation 3.5.5.3.1 Radiation with the Environment Thermal radiation occurs between a surface and its environment due to thermally excited conditions within the matter. The amount of radiation exchange depends on the temperature, emissivity and surface area:

Q)$T = A MT- 4 TU 4 P (Equation 13.27, Page 885 [5].)

where, e = emissivity, s = Stefan-Boltzmann constant (1.19 E -11 Btu/h-in²-°F),

A = surface area, Ts = surface temperature (°R), and T¥ = temperature of surroundings (°R).

This equation is read as the difference in the quantity of radiation emitting from the surface and the quantity of radiation entering the surface. Further, it may be advantageous to model the net heat exchange in a comparable manner to convection to linearize the rate equation as:

Q)$T = h) A (T- TU ) (Equation 1.8, Page 10 [5])

Setting the above radiation heat exchange equations equal to each other and performing some algebraic manipulation results in:

hr = MT- 3 + TU 3 P(T- + TU ) (Equation 1.9, Page 10 [5])

where, hr = radiation heat transfer coefficient 3-71

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.5.3.2 Radiation between surfaces The equation for radiation heat transfer between surfaces is:

VWN. 2 O N! 2 X QradS = .EF. . .EF! (Equation 13.23, Page 885 [5])

?  ?

F. G . G. H.! F! G !

where, T6 = Temperature of surface 1 T3 = Temperature of surface 2

= Stefan-Boltzmann constant A6 = Area of surface 1 A3 = Area of surface 2 6 = Emissivity of surface 1 3 = Emissivity of surface 2 F63 = View factor between surfaces 1 and 2 3.5.5.4 Conduction The conduction heat transfer on a body depends on the temperature difference of the material, the thermal conductivity (k) of the material and the area of heat transfer:

N QY = kA Y (Equation 2.1, Page 69 [5])

where, k = Thermal conductivity constant (W/m*K)

T = Temperature difference A = Area of heat transfer x = Length of the material in the direction of heat flow 3.5.5.5 Thermal Resistance 3.5.5.5.1 Thermal Resistance for Conduction The temperature change across boundaries where different materials meet may be considerable and is known as thermal contact resistance Rt,c, and is due to primarily surface roughness effects.

These rough areas create raised areas and therefore gaps as well between components.

The thermal resistance for conduction heat transfer is defined as:

NG ONI Rt,c = [J (Equation 3.6, Page 114 [5])

= 7\

where, T\ = Temperature of material A T] = Temperature of material B qx = Conduction heat transfer L = Length of wall A = Area normal to the direction of heat transfer 3-72

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 3.5.5.5.2 Thermal Resistance for Convection The resistance for convection heat transfer is:

NB ONC Rt,conv = (Equation 3.9, Page 115 [5])

[

6

=

(\

where, T- = Surface temperature TU = Environment temperature q = Convection heat transfer A = Area of convection h = Convection coefficient 3.5.5.5.3 Thermal Resistance for Radiation The resistance for radiation heat transfer is:

NB ONBK+

Rt,rad = (Equation 3.13, Page 115 [5])

[+%L 6

= (+ \

where, T- = Surface temperature T-9) = Surrounding temperature Q)$T = Convection heat transfer A = Area of radiation h) = Radiation coefficient 3-73

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 CONTENTS 4 CONTAINMENT .......................................................................................................................... 4-1 4.1 Description of the Containment System ................................................................................. 4-1 4.2 Containment under Normal Conditions of Transport ....................................................... 4-1 4.3 Containment Requirements for Hypothetical Accident Conditions.............................. 4-1 4.4 Leakage Rate Tests for Type B Packages................................................................................ 4-2 4.5 References ........................................................................................................................................ 4-2 4.6 List of Appendices .......................................................................................................................... 4-2 4-i

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 4 CONTAINMENT 4.1 Description of the Containment System The containment boundary of the package is defined as the payload vessel with its associated welds, payload vessel high temperature heat resistant fiberglass sleeve gasket, payload vessel blind flange, and reinforcing ring.

The payload vessel is comprised of a 10-gauge (0.3416 cm) carbon steel sheet for the body and bottom. The upper end of the vessel is fitted with a 1/4 (0.635 cm) inner carbon steel flange ring with a 1/2 (1.27 cm) thick carbon steel blind flange. The vessel has three circumferential welds (two at the flange, one at the base) and one longitudinal weld. A 1/8 (0.3175 cm) high temperature resistant silicone coated fiberglass gasket is used between the steel flange ring and blind flange.

The payload vessel blind flange is secured to the flange with twelve 1/2 (1.27 cm) bolts. There are no penetrations, valves or venting devices used within the containment boundary. An illustration showing the components of the containment system is provided in Figure 1-1.

Additionally, weld standards and codes are specified in the licensing drawing general notes in Section 1.4.2.

A specified torque is applied to the closure bolts and tightened as part of the closure steps defined within Section 7.1.2 to assure positive closure of the containment boundary. Given the mode of the closure, it cannot be opened unintentionally. The use of lock washers assures that the closure bolts are not loosened due to vibration during shipment. A location for installation of a tamper-indicating device is provided at the drum closure.

4.2 Containment under Normal Conditions of Transport The Versa-Pac is classified as a Type A Fissile package. Performance tests consistent with the requirements of 10 CFR 71.71 and 10 CFR 71.73 [1] have demonstrated that the Versa-Pac effectively prevents loss or dispersal of the radioactive contents under the postulated conditions of transport. Section 2.0 provides a description of the tests performed and analyses completed.

Section 6.0 demonstrates that the package remains subcritical under Normal and Hypothetical Accident Conditions.

Due to gas permeation through the silicone seal, the internal pressure is expected to be maintained near atmospheric pressure for all conditions of transport. (Note that the normal hot maximum temperature for the contents, reported in Section 3.1.3, is 147 °F.)

4.3 Containment Requirements for Hypothetical Accident Conditions As discussed in Section 4.2 and Section 2.0, performance tests consistent with the requirements of 10 CFR 71.71 and 10 CFR 71.73 [1] have demonstrated that the Versa-Pac effectively prevents loss or dispersal of the radioactive contents under the postulated conditions of transport. Section 6.0 demonstrates that the package remains subcritical under normal and hypothetical accident conditions.

Due to gas permeation through the silicone seal, the internal pressure of the package is expected to be maintained near atmospheric pressure for all conditions of transport, with pressure build up relieved through the package closure. However, as demonstrated in Section 3.0, pressure buildup does not affect the structural integrity of the containment system.

4-1

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 4.4 Leakage Rate Tests for Type B Packages This section is not applicable.

4.5 References

[1] Nuclear Regulatory Commission (NRC), Title 10, Part 71-Packaging and Transportation of Radioactive Material.

4.6 List of Appendices No appendices.

4-2

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 CONTENTS 5 SHIELDING .................................................................................................................................... 5-1 5.1 References .......................................................................................................................................... 5-1 5-i

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 5 SHIELDING Gamma and neutron shielding are not required for the materials transported in the Versa-Pac.

However, it is the responsibility of the shipper to assure compliance with 10 CFR 71.47 [1]

regarding radiation standards for each individual shipment. Performance tests have demonstrated that there is no substantial reduction in the effectiveness of the packaging during Normal Conditions of Transport; thus, there is no significant increase in external surface radiation levels resulting from the postulated conditions of transport.

5.1 References

[1] Nuclear Regulatory Commission (NRC), Title 10, Part 71-Packaging and Transportation of Radioactive Material.

5-1

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 CONTENTS 6 CRITICALITY EVALUATION ................................................................................................................... 6-1 6.1 Description of the Criticality Design ........................................................................................ 6-1 6.1.1 Design Features ........................................................................................................................................ 6-1 6.1.2 Summary Table of Criticality Evaluation ....................................................................................... 6-3 6.1.3 Criticality Safety Index (CSI) ............................................................................................................ 6-12 6.2 Fissile Material Contents ........................................................................................................... 6-13 6.2.1 Standard Configuration ...................................................................................................................... 6-13 6.2.2 Hydrogen-Limited Standard Contents Including TRISO Fuels .......................................... 6-14 6.2.3 5-inch Pipe ............................................................................................................................................... 6-15 6.2.4 5-inch Pipe Hydrogen-Limited Contents .................................................................................... 6-16 6.2.5 1S/2S Cylinder Configuration .......................................................................................................... 6-17 6.2.6 High-Capacity Basket with Hydrogen-Limited Contents ..................................................... 6-18 6.3 General Considerations.............................................................................................................. 6-19 6.3.1 Model Configuration ............................................................................................................................ 6-19 6.3.2 Material Properties .............................................................................................................................. 6-26 6.3.3 Computer Codes and Cross Section Libraries........................................................................... 6-30 6.3.4 Demonstration of Maximum Reactivity ...................................................................................... 6-31 6.4 Single Package Evaluation......................................................................................................... 6-52 6.4.1 Standard Configuration ...................................................................................................................... 6-52 6.4.2 Hydrogen-Limited Contents Including TRISO Fuels .............................................................. 6-70 6.4.3 5-inch Pipe ............................................................................................................................................... 6-75 6.4.4 5-inch Pipe with Hydrogen-Limited Contents .......................................................................... 6-80 6.4.5 1S/2S Cylinder ....................................................................................................................................... 6-82 6.4.6 High-Capacity Basket with Hydrogen-Limited Contents ..................................................... 6-99 6.5 Evaluation of Package Arrays Under Normal Conditions of Transport .................. 6-100 6.5.1 Standard Configuration .................................................................................................................... 6-102 6.5.2 Hydrogen-Limited Contents Including TRISO Fuels ............................................................ 6-128 6.5.3 5-inch Pipe ............................................................................................................................................. 6-141 6.5.4 5-inch Pipe with Hydrogen-Limited Contents ........................................................................ 6-150 6.5.5 1S/2S Cylinder ..................................................................................................................................... 6-152 6.5.6 High-Capacity Basket with Hydrogen-Limited Contents ................................................... 6-171 6.6 Evaluation of Package Arrays Under Hypothetical Accident Conditions ............... 6-175 6.6.1 Standard Configuration .................................................................................................................... 6-177 6.6.2 Hydrogen-Limited Contents Including TRISO Fuels ............................................................ 6-203 6.6.3 5-inch Pipe ............................................................................................................................................. 6-219 6.6.4 5-inch Pipe with Hydrogen-Limited Contents ........................................................................ 6-236 6.6.5 1S/2S Cylinder ..................................................................................................................................... 6-242 6.6.6 High-Capacity Basket with Hydrogen-Limited Contents ................................................... 6-272 6.7 Fissile Material Packages for Air Transport .................................................................... 6-284 6.7.1 Configuration ........................................................................................................................................ 6-284 6.7.2 Results...................................................................................................................................................... 6-284 6-i

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.8 Benchmark Evaluations .......................................................................................................... 6-292 6.8.1 Applicability of Benchmark Experiments................................................................................. 6-292 6.8.2 Bias Determination ............................................................................................................................ 6-301 6.9 Appendix ...................................................................................................................................... 6-305 6.9.1 References .............................................................................................................................................. 6-305 6-ii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 TABLES TABLE 6.1.2-1.

SUMMARY

OF THE STANDARD CONFIGURATION ANALYSIS ........................................................................................ 6-3 TABLE 6.1.2-2.

SUMMARY

TABLE OF HYDROGEN-LIMITED CRITICALITY EVALUATION ................................................................... 6-4 TABLE 6.1.2-3.

SUMMARY

OF THE VP-55 WITH 5-INCH PIPE CONTAINER EVALUATION ................................................................ 6-5 TABLE 6.1.2-4.

SUMMARY

OF THE VP-55 WITH 5-INCH PIPE CONTAINER HYDROGEN-LIMITED CONTENTS EVALUATION...... 6-6 TABLE 6.1.2-5. SINGLE PACKAGE VP-55 1S/2S CYLINDER CONTENTS EVALUATION

SUMMARY

................................................. 6-7 TABLE 6.1.2-6. NCT PACKAGE ARRAY VP-55 1S/2S CYLINDER CONTENTS EVALUATION

SUMMARY

........................................ 6-7 TABLE 6.1.2-7. HAC PACKAGE ARRAY VP-55 1S/2S CYLINDER CONTENTS EVALUATION

SUMMARY

........................................ 6-8 TABLE 6.1.2-8.

SUMMARY

OF THE VP-55 WITH HIGH-CAPACITY BASKET HYDROGEN-LIMITED CONTENTS EVALUATION ...... 6-9 TABLE 6.1.2-9. UPPER SUBCRITICAL LIMITS FOR ALL VERSA-PAC CONFIGURATIONS ................................................................... 6-10 TABLE 6.1.3-1. CRITICALITY SAFETY INDICES FOR ALL CONTENTS................................................................................................... 6-12 TABLE 6.2.1-1. URANIUM MASS LIMITS FOR STANDARD CONFIGURATION ...................................................................................... 6-13 TABLE 6.2.2-1. URANIUM MASS LIMITS FOR 1 LB. HYDROGEN-LIMITED CONTENTS..................................................................... 6-14 TABLE 6.2.3-1. URANIUM MASS LIMITS - VP-55 WITH 5-INCH PIPE CONFIGURATION ............................................................... 6-15 TABLE 6.2.4-1. URANIUM MASS LIMITS - VP-55 WITH 5-INCH PIPE HYDROGEN-LIMITED CONTENTS ................................... 6-16 TABLE 6.2.5-1. MAXIMUM QUANTITY OF 1S/2S CYLINDERS AND URANIUM LIMITS FOR THE VP-55....................................... 6-17 TABLE 6.2.6-1. URANIUM MASS LIMITS - VP-55 WITH HCB HYDROGEN-LIMITED CONTENTS ................................................. 6-18 TABLE 6.3.1-1. VP-55 RADIAL DIMENSIONS ........................................................................................................................................ 6-20 TABLE 6.3.1-2. VP-55 AXIAL DIMENSIONS ........................................................................................................................................... 6-20 TABLE 6.3.2-1.

SUMMARY

OF COMPOUND MATERIAL COMPOSITIONS ............................................................................................. 6-28 TABLE 6.3.2-2.

SUMMARY

OF ELEMENTAL/MIXTURE MATERIAL COMPOSITIONS ......................................................................... 6-28 TABLE 6.3.2-3.

SUMMARY

OF BOUNDING URANIUM COMPOUNDS FOR HCB CONFIGURATION .................................................... 6-29 TABLE 6.3.2-4. HCB CPVC PROPERTIES ............................................................................................................................................... 6-29 TABLE 6.3.3-1. NEUTRON HISTORY SPECIFICATION ............................................................................................................................ 6-30 TABLE 6.3.4-1. ARRAY INDEX VS. ARRAY SIZE ...................................................................................................................................... 6-34 TABLE 6.3.4-2.

SUMMARY

TABLE OF 1S/2S CYLINDER MODELING CONFIGURATION................................................................... 6-41 TABLE 6.3.4-3. SINGLE PACKAGE STUDIES FOR EACH CONFIGURATION ........................................................................................... 6-42 TABLE 6.3.4-4. PACKAGE ARRAY STUDIES FOR EACH CONFIGURATION ........................................................................................... 6-42 TABLE 6.4.1-1. HOMOGENEOUS FISSILE MASS - 100-WT.% 235U STANDARD SINGLE PACKAGE ............................................... 6-53 TABLE 6.4.1-2. HETEROGENEOUS FISSILE MASS - 100-WT.% 235U STANDARD SINGLE PACKAGE ........................................... 6-53 TABLE 6.4.1-3. FISSILE MASS POSITION - 100-WT.% 235U STANDARD SINGLE PACKAGE .......................................................... 6-54 TABLE 6.4.1-4. THORIUM ADDITION STUDY - 100-WT.% 235U STANDARD SINGLE PACKAGE ................................................... 6-54 TABLE 6.4.1-5. HOMOGENEOUS FISSILE MASS WT.% 235U STANDARD SINGLE PACKAGE.................................................. 6-56 TABLE 6.4.1-6. HETEROGENEOUS FISSILE MASS WT.% 235U STANDARD SINGLE PACKAGE .............................................. 6-56 TABLE 6.4.1-7. FISSILE MASS POSITION WT.% 235U STANDARD SINGLE PACKAGE ............................................................ 6-57 TABLE 6.4.1-8. THORIUM ADDITION STUDY WT.% 235U STANDARD SINGLE PACKAGE...................................................... 6-57 TABLE 6.4.1-9. HOMOGENEOUS FISSILE MASS WT.% 235U STANDARD SINGLE PACKAGE.................................................. 6-59 TABLE 6.4.1-10. HETEROGENEOUS FISSILE MASS WT.% 235U STANDARD SINGLE PACKAGE ........................................... 6-59 TABLE 6.4.1-11. FISSILE MASS POSITION WT.% 235U STANDARD SINGLE PACKAGE .......................................................... 6-60 TABLE 6.4.1-12. THORIUM ADDITION STUDY WT.% 235U STANDARD SINGLE PACKAGE ................................................... 6-60 TABLE 6.4.1-13. HOMOGENEOUS FISSILE MASS WT.% 235U STANDARD SINGLE PACKAGE.................................................. 6-62 TABLE 6.4.1-14. HETEROGENEOUS FISSILE MASS WT.% 235U STANDARD SINGLE PACKAGE .............................................. 6-62 TABLE 6.4.1-15. HETEROGENEOUS FISSILE MASS WITH HDPE WT.% 235U STANDARD SINGLE PACKAGE ...................... 6-63 TABLE 6.4.1-16. FISSILE MASS POSITION WT.% 235U STANDARD SINGLE PACKAGE ............................................................ 6-63 TABLE 6.4.1-17. THORIUM ADDITION STUDY WT.% 235U SINGLE STANDARD PACKAGE...................................................... 6-63 TABLE 6.4.1-18. HOMOGENEOUS FISSILE MASS - 1.25-WT.% 235U STANDARD SINGLE PACKAGE ........................................... 6-66 TABLE 6.4.1-19. HETEROGENEOUS FISSILE MASS - 1.25-WT.% 235U STANDARD SINGLE PACKAGE ........................................ 6-66 TABLE 6.4.1-20. HETEROGENEOUS FISSILE MASS WITH HDPE - 1.25-WT.% 235U STANDARD SINGLE PACKAGE ................ 6-67 TABLE 6.4.1-21. FISSILE MASS POSITION - 1.25-WT.% 235U STANDARD SINGLE PACKAGE ...................................................... 6-67 TABLE 6.4.1-22. THORIUM ADDITION STUDY - 1.25-WT.% 235U STANDARD SINGLE PACKAGE ............................................... 6-67 TABLE 6.4.2-1. 100-WT.% 235U HYDROGEN LIMITED CONTENT SINGLE PACKAGE RESULTS .................................................... 6-70 TABLE 6.4.2-2. 20-WT.% 235U HYDROGEN LIMITED CONTENT SINGLE PACKAGE RESULTS ....................................................... 6-71 6-iii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 TABLE 6.4.2-3. 10-WT.% 235U HYDROGEN LIMITED CONTENT SINGLE PACKAGE RESULTS ....................................................... 6-72 TABLE 6.4.2-4. 5-WT.% 235U HYDROGEN LIMITED CONTENT SINGLE PACKAGE RESULTS .......................................................... 6-73 TABLE 6.4.2-5. 5-WT.% 235U PARTICLE SIZE STUDY HYDROGEN LIMITED CONTENT SINGLE PACKAGE .................................. 6-74 TABLE 6.4.3-1.

SUMMARY

OF THE SINGLE PACKAGE EVALUATION OF THE VP-55 WITH 5-INCH PIPE CONTAINER ................ 6-75 TABLE 6.4.3-2. FILL PERCENTAGE SENSITIVITY OF THE 5-INCH PIPE CONTAINER - SINGLE PACKAGE ...................................... 6-76 TABLE 6.4.3-3. PARTIAL FILL SENSITIVITY OF THE 5-INCH PIPE CONTAINER - SINGLE PACKAGE ............................................. 6-77 TABLE 6.4.3-4. PARTIAL U-235 MASS SENSITIVITY OF 5-INCH PIPE CONTAINER - SINGLE PACKAGE ..................................... 6-79 TABLE 6.4.4-1.

SUMMARY

5-INCH PIPE HYDROGEN LIMITED CONTENT SINGLE PACKAGE CRITICALITY EVALUATION .......... 6-80 TABLE 6.4.5-1.

SUMMARY

TABLE OF 1S CYLINDER SINGLE PACKAGE CRITICALITY EVALUATION .............................................. 6-82 TABLE 6.4.5-2.

SUMMARY

TABLE OF 2S CYLINDER SINGLE PACKAGE CRITICALITY EVALUATION .............................................. 6-82 TABLE 6.4.5-3. EFFECT OF 5-INCH PIPE SPACING - 1S, 100-WT.% U-235, SINGLE PACKAGE .................................................. 6-83 TABLE 6.4.5-4. EFFECT OF URANIUM MASS - 1S, 100-WT.% U-235, SINGLE PACKAGE ............................................................ 6-83 TABLE 6.4.5-5. EFFECT OF 5-INCH PIPE FILL HEIGHT - 1S, 100-WT.% U-235, SINGLE PACKAGE .......................................... 6-83 TABLE 6.4.5-6. EFFECT OF CYLINDER POSITION - 1S, 100-WT.% U-235, SINGLE PACKAGE .................................................... 6-85 TABLE 6.4.5-7. EFFECT OF UF6 - 1S, 100-WT.% U-235, SINGLE PACKAGE ................................................................................. 6-86 TABLE 6.4.5-8. EFFECT OF FILL HEIGHT - 2S, 100-WT.% U-235, SINGLE PACKAGE ................................................................. 6-87 TABLE 6.4.5-9. EFFECT OF URANIUM MASS - 2S, 100-WT.% U-235, SINGLE PACKAGE ............................................................ 6-87 TABLE 6.4.5-10. EFFECT OF CYLINDER POSITIONING - 2S, 100-WT.% U-235, SINGLE PACKAGE ........................................... 6-89 TABLE 6.4.5-11. EFFECT OF UF6 - 2S, 100-WT.% U-235, SINGLE PACKAGE .............................................................................. 6-89 TABLE 6.4.5-12. EFFECT OF SPHERE SIZE - 1S, 20-WT.% U-235, SINGLE PACKAGE ................................................................. 6-91 TABLE 6.4.5-13. EFFECT OF URANIUM MASS - 1S, 20-WT.% U-235, SINGLE PACKAGE ............................................................ 6-91 TABLE 6.4.5-14. EFFECT OF FISSILE SPHERE POSITION - 1S, 20-WT.% U-235, SINGLE PACKAGE .......................................... 6-93 TABLE 6.4.5-15. EFFECT OF UF6 - 1S, 20-WT.% U-235, SINGLE PACKAGE ................................................................................. 6-93 TABLE 6.4.5-16. EFFECT OF SPHERE SIZE - 2S, 20-WT.% U-235, SINGLE PACKAGE ................................................................. 6-95 TABLE 6.4.5-17. EFFECT OF URANIUM MASS - 2S, 20-WT.% U-235, SINGLE PACKAGE ............................................................ 6-95 TABLE 6.4.5-18. EFFECT OF FISSILE POSITION ON KEFF - 2S, 20-WT.% U-235, SINGLE PACKAGE ............................................ 6-97 TABLE 6.4.5-19. EFFECT OF UF6 ON KEFF - 2S, 20-WT.% U-235, SINGLE PACKAGE .................................................................... 6-97 TABLE 6.4.6-1. HCB HYDROGEN-LIMITED CONTENT SINGLE PACKAGE CRITICALITY EVALUATION .......................................... 6-99 TABLE 6.5-1. NCT PACKAGE ARRAY CONFIGURATIONS ................................................................................................................... 6-100 TABLE 6.5.1-1. HOMOGENEOUS FISSILE MASS SIZE - 100-WT.% 235U STANDARD NCT ARRAY............................................ 6-103 TABLE 6.5.1-2. HDPE CAVITY VOLUME FRACTION - 100-WT.% 235U STANDARD NCT ARRAY ............................................ 6-103 TABLE 6.5.1-3. HETEROGENEOUS FISSILE MASS SIZE - 100-WT.% 235U STANDARD NCT ARRAY ........................................ 6-103 TABLE 6.5.1-4. FISSILE MASS POSITION - 100-WT.% 235U, HDPE CAVITY, STANDARD NCT ARRAY .................................. 6-103 TABLE 6.5.1-5. ARRAY CONFIGURATION STUDY - 100-WT.% 235U STANDARD NCT ARRAY .................................................. 6-104 TABLE 6.5.1-6. HOMOGENEOUS FISSILE MASS SIZE - DRY CAVITY, 20-WT.% 235U STANDARD NCT ARRAY ...................... 6-107 TABLE 6.5.1-7. HOMOGENEOUS FISSILE MASS SIZE - HDPE CAVITY, 20-WT.% 235U STANDARD NCT ARRAY .................. 6-108 TABLE 6.5.1-8. HDPE CAVITY VOLUME FRACTION WT.% 235U STANDARD NCT ARRAY............................................... 6-108 TABLE 6.5.1-9. HETEROGENEOUS PARTICLE RESULTS 445 G235U WT.% 235U STANDARD NCT ARRAY ..................... 6-108 TABLE 6.5.1-10. FISSILE MASS POSITION WT.% 235U STANDARD NCT PACKAGE ARRAY ............................................. 6-109 TABLE 6.5.1-11. ARRAY CONFIGURATION STUDY WT.% 235U, STANDARD NCT ARRAY ................................................. 6-109 TABLE 6.5.1-12. HOMOGENEOUS FISSILE MASS SIZE - DRY CAVITY, 10-WT.% 235U STANDARD NCT ARRAY.................... 6-112 TABLE 6.5.1-13. HOMOGENEOUS FISSILE MASS SIZE - HDPE CAVITY, 10-WT.% 235U STANDARD NCT ARRAY ............... 6-113 TABLE 6.5.1-14. HDPE CAVITY VOLUME FRACTION WT.% 235U, HDPE CAVITY, STANDARD NCT ARRAY ............... 6-113 TABLE 6.5.1-15. HETEROGENEOUS PARTICLE 505 G235U - DRY CAVITY, 10-WT.% 235U STANDARD NCT ARRAY ........... 6-113 TABLE 6.5.1-16. FISSILE MASS POSITION WT.% 235U STANDARD NCT PACKAGE ARRAY ............................................. 6-114 TABLE 6.5.1-17. ARRAY CONFIGURATION STUDY WT.% 235U, STANDARD NCT ARRAY ................................................. 6-114 TABLE 6.5.1-18. HOMOGENEOUS FISSILE MASS - DRY CAVITY, 5-WT.% 235U STANDARD NCT ARRAY ............................... 6-117 TABLE 6.5.1-19. HOMOGENEOUS FISSILE MASS - HDPE CAVITY, 5-WT.% 235U STANDARD NCT ARRAY ........................... 6-118 TABLE 6.5.1-20. HDPE CAVITY VOLUME FRACTION WT.% 235U STANDARD NCT ARRAY............................................... 6-118 TABLE 6.5.1-21. HETEROGENEOUS PARTICLE RESULTS 630 G235U WT.% 235U STANDARD NCT ARRAY ..................... 6-118 TABLE 6.5.1-22. HETEROGENEOUS PARTICLE RESULTS 610 G235U WT.% 235U STANDARD NCT ARRAY ..................... 6-119 TABLE 6.5.1-23. FISSILE MASS POSITION WT.% 235U STANDARD NCT ARRAY .................................................................. 6-119 6-iv

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 TABLE 6.5.1-24. ARRAY CONFIGURATION STUDY WT.% 235U STANDARD NCT ARRAY .................................................... 6-119 TABLE 6.5.1-25. HOMOGENEOUS FISSILE MASS SIZE - 1.25-WT.% 235U STANDARD NCT ARRAY ........................................ 6-123 TABLE 6.5.1-26. HDPE CAVITY VOLUME FRACTION - 1.25-WT.% 235U STANDARD NCT ARRAY ........................................ 6-124 TABLE 6.5.1-27. HETEROGENEOUS PARTICLE RESULTS 2000 G235U - 1.25-WT.% 235U STANDARD NCT ARRAY ............ 6-124 TABLE 6.5.1-28. HETEROGENEOUS PARTICLE RESULTS 1650 G235U - 1.25-WT.% 235U STANDARD NCT ARRAY ............ 6-124 TABLE 6.5.1-29. FISSILE MASS POSITION - 1.25-WT.% 235U STANDARD NCT ARRAY............................................................ 6-125 TABLE 6.5.1-30. ARRAY CONFIGURATION STUDY - 1.25-WT.% 235U STANDARD NCT ARRAY .............................................. 6-125 TABLE 6.5.2-1. 100-WT.% 235U HYDROGEN-LIMITED CONTENT NCT ARRAY RESULTS ......................................................... 6-128 TABLE 6.5.2-2. HOMOGENEOUS GRAPHITE MODERATOR RESULTS - 100-WT.% 235U HYDROGEN-LIMITED NCT ARRAY 6-130 TABLE 6.5.2-3. HETEROGENEOUS GRAPHITE MODERATOR - 100-WT.% 235U HYDROGEN-LIMITED NCT ARRAY ............. 6-130 TABLE 6.5.2-4. 20-WT.% 235U HYDROGEN-LIMITED CONTENT NCT ARRAY RESULTS ............................................................ 6-132 TABLE 6.5.2-5. HOMOGENEOUS GRAPHITE MODERATOR RESULTS WT.% 235U HYDROGEN-LIMITED NCT ARRAY .. 6-133 TABLE 6.5.2-6. HETEROGENEOUS GRAPHITE MODERATOR RESULTS WT.% 235U HYDROGEN-LIMITED NCT ARRAY6-134 TABLE 6.5.2-7. 10-WT.% 235U HYDROGEN-LIMITED CONTENT NCT ARRAY RESULTS ............................................................ 6-135 TABLE 6.5.2-8. HOMOGENEOUS GRAPHITE MODERATOR RESULTS WT.% 235U HYDROGEN-LIMITED NCT ARRAY .. 6-136 TABLE 6.5.2-9. HETEROGENEOUS GRAPHITE MODERATOR RESULTS WT.% 235U HYDROGEN-LIMITED NCT ARRAY6-137 TABLE 6.5.2-10. 5-WT.% 235U HYDROGEN-LIMITED CONTENT NCT ARRAY RESULTS ............................................................ 6-138 TABLE 6.5.2-11. HOMOGENEOUS GRAPHITE MODERATOR RESULTS WT.% 235U HYDROGEN-LIMITED NCT ARRAY .. 6-139 TABLE 6.5.2-12. HETEROGENEOUS GRAPHITE MODERATOR RESULTS WT.% 235U HYDROGEN-LIMITED NCT ARRAY6-140 TABLE 6.5.3-1.

SUMMARY

OF LIMITING CASES FOR NCT PACKAGE ARRAY EVALUATION ......................................................... 6-141 TABLE 6.5.3-2. FILL PERCENTAGE SENSITIVITY OF THE 5-INCH PIPE CONTAINER - NCT PACKAGE ARRAY ......................... 6-142 TABLE 6.5.3-3. U-235 MASS SENSITIVITY OF THE 5-INCH PIPE CONTAINER - NCT PACKAGE ARRAY .................................. 6-143 TABLE 6.5.3-4. ARRAY CONFIGURATION SENSITIVITY OF THE 5-INCH PIPE - U(100) NCT PACKAGE ARRAY..................... 6-146 TABLE 6.5.3-5. ARRAY CONFIGURATION SENSITIVITY OF THE 5-INCH PIPE - U(20) NCT PACKAGE ARRAY ....................... 6-146 TABLE 6.5.3-6. ARRAY CONFIGURATION SENSITIVITY OF THE 5-INCH PIPE CONTAINER - U(10) NCT PACKAGE ARRAY . 6-146 TABLE 6.5.3-7. PARTIAL FILL SENSITIVITY OF THE 5-INCH PIPE CONTAINER - NCT PACKAGE ARRAY ................................. 6-149 TABLE 6.5.4-1.

SUMMARY

5-INCH PIPE HYDROGEN LIMITED CONTENT NCT ARRAY CRITICALITY EVALUATION ................ 6-150 TABLE 6.5.5-1. EFFECT OF CYLINDER SPACING ON KEFF - 1S, 100-WT.% U-235, NCT PACKAGE ARRAY ............................ 6-152 TABLE 6.5.5-2. EFFECT OF REFLECTOR THICKNESS ON KEFF - 1S, 100-WT.% U-235, NCT PACKAGE ARRAY..................... 6-152 TABLE 6.5.5-3. EFFECT OF URANIUM MASS ON KEFF - 1S, 100-WT.% U-235, NCT PACKAGE ARRAY .................................. 6-153 TABLE 6.5.5-4. EFFECT OF FILL HEIGHT ON KEFF + 2 - 1S, 100-WT.% U-235, NCT PACKAGE ARRAY .............................. 6-153 TABLE 6.5.5-5. EFFECT OF CYLINDER POSITIONING ON KEFF + 2 - 1S, 100-WT.% U-235, NCT PACKAGE ARRAY ........... 6-155 TABLE 6.5.5-6. EFFECT OF ARRAY CONFIGURATION ON KEFF + 2- 1S, 100-WT.% U-235, NCT PACKAGE ARRAY ........... 6-156 TABLE 6.5.5-7. EFFECT OF UF6 ON KEFF + 2 - 1S, 100-WT.% U-235, NCT PACKAGE ARRAY .............................................. 6-156 TABLE 6.5.5-8. EFFECT OF REFLECTOR THICKNESS ON KEFF - 2S, 100-WT.% U-235, NCT PACKAGE ARRAY..................... 6-157 TABLE 6.5.5-9. EFFECT OF URANIUM MASS ON KEFF - 2S, 100-WT.% U-235, NCT PACKAGE ARRAY .................................. 6-157 TABLE 6.5.5-10. EFFECT OF FILL HEIGHT ON KEFF - 2S, 100-WT.% U-235, NCT PACKAGE ARRAY ..................................... 6-157 TABLE 6.5.5-11. EFFECT OF CYLINDER GROUP POSITIONING ON KEFF - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY ....... 6-159 TABLE 6.5.5-12. EFFECT OF ARRAY CONFIGURATION ON KEFF - 2S, 100-WT.% U-235, NCT PACKAGE ARRAY ................. 6-159 TABLE 6.5.5-13. EFFECT OF UF6 ON KEFF - 2S, 100-WT.% U-235, NCT PACKAGE ARRAY ..................................................... 6-160 TABLE 6.5.5-14. EFFECT OF CYLINDER SPACING ON KEFF - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY ............................ 6-161 TABLE 6.5.5-15. EFFECT OF REFLECTOR THICKNESS ON KEFF - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY..................... 6-161 TABLE 6.5.5-16. EFFECT OF URANIUM MASS ON KEFF - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY .................................. 6-161 TABLE 6.5.5-17. EFFECT OF FILL HEIGHT ON KEFF - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY ........................................ 6-162 TABLE 6.5.5-18. EFFECT OF CYLINDER GROUP POSITIONING ON KEFF - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY ....... 6-164 TABLE 6.5.5-19. EFFECT OF ARRAY CONFIGURATION ON KEFF - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY .................... 6-164 TABLE 6.5.5-20. EFFECT OF UF6 ON KEFF + 2 - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY .............................................. 6-165 TABLE 6.5.5-21. EFFECT OF CYLINDER SPACING ON KEFF - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY ............................ 6-166 TABLE 6.5.5-22. EFFECT OF REFLECTOR THICKNESS ON KEFF - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY..................... 6-166 TABLE 6.5.5-23. EFFECT OF URANIUM MASS ON KEFF - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY .................................. 6-166 TABLE 6.5.5-24. EFFECT OF FILL HEIGHT ON KEFF - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY ........................................ 6-167 TABLE 6.5.5-25. EFFECT OF CYLINDER GROUP POSITIONING ON KEFF - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY ....... 6-169 6-v

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 TABLE 6.5.5-26. EFFECT OF ARRAY CONFIGURATION ON KEFF - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY .................... 6-169 TABLE 6.5.5-27. EFFECT OF UF6 ON KEFF - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY ....................................................... 6-170 TABLE 6.5.6-1. OPTIMALLY MODERATED CPVC COMPOUND HOMOGENEOUS RESULTS - NCT ARRAY ................................. 6-171 TABLE 6.5.6-2. BOUNDING CPVC COMPOUND EVALUATION KEFF RESULTS - NCT ARRAY ........................................................ 6-172 TABLE 6.5.6-3. NCT ARRAY HCB HOMOGENEOUS CASE

SUMMARY

WT.% 235U UC ....................................................... 6-173 TABLE 6.5.6-4. HCB STUDY RESULTS - NCT ARRAY ....................................................................................................................... 6-174 TABLE 6.6-1. HAC PACKAGE ARRAY CONFIGURATIONS ................................................................................................................... 6-175 TABLE 6.6.1-1. HOMOGENEOUS FISSILE MASS SIZE - HDPE CAVITY, 100-WT.% 235U STANDARD HAC ARRAY ............... 6-178 TABLE 6.6.1-2. HOMOGENEOUS FISSILE MASS SIZE - DRY CAVITY, 100-WT.% 235U STANDARD HAC ARRAY ................... 6-178 TABLE 6.6.1-3. HDPE CAVITY VOLUME FRACTION - 100-WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY............... 6-178 TABLE 6.6.1-4. HETEROGENEOUS PARTICLES - 360 G235U, DRY CAVITY, 100-WT.% 235U, STANDARD HAC ARRAY ....... 6-179 TABLE 6.6.1-5. FISSILE MASS POSITION - 100-WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY .................................. 6-179 TABLE 6.6.1-6. FLOODING STUDY

SUMMARY

- 100-WT.% 235U, HDPE CAVITY, HAC ARRAY .............................................. 6-179 TABLE 6.6.1-7. ARRAY CONFIGURATION STUDY - 100-WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY .................... 6-180 TABLE 6.6.1-8. HOMOGENEOUS FISSILE MASS SIZE WT.% 235U, STANDARD HAC ARRAY ............................................. 6-184 TABLE 6.6.1-9. HDPE CAVITY VOLUME FRACTION WT.% 235U, STANDARD HAC ARRAY ............................................. 6-184 TABLE 6.6.1-10. HETEROGENEOUS FISSILE MASS SIZE WT.% 235U, STANDARD HAC ARRAY ....................................... 6-184 TABLE 6.6.1-11. FISSILE MASS POSITION WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY .................................. 6-184 TABLE 6.6.1-12. FLOODING STUDY

SUMMARY

WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY .......................... 6-185 TABLE 6.6.1-13. ARRAY CONFIGURATION STUDY WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY .................... 6-185 TABLE 6.6.1-14. HOMOGENEOUS FISSILE MASS SIZE WT.% 235U, STANDARD HAC ARRAY .......................................... 6-189 TABLE 6.6.1-15. HDPE CAVITY VOLUME FRACTION WT.% 235U, STANDARD HAC ARRAY ........................................... 6-189 TABLE 6.6.1-16. HETEROGENEOUS FISSILE MASS SIZE WT.% 235U, STANDARD HAC ARRAY ....................................... 6-189 TABLE 6.6.1-17. FISSILE MASS POSITION WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY .................................. 6-189 TABLE 6.6.1-18. FLOODING STUDY

SUMMARY

WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY .......................... 6-190 TABLE 6.6.1-19. ARRAY CONFIGURATION STUDY WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY .................... 6-190 TABLE 6.6.1-20. HOMOGENEOUS FISSILE MASS SIZE WT.% 235U, STANDARD HAC ARRAY ............................................. 6-194 TABLE 6.6.1-21. HDPE CAVITY VOLUME FRACTION WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY ................. 6-194 TABLE 6.6.1-22. HETEROGENEOUS FISSILE MASS SIZE WT.% 235U, STANDARD HAC ARRAY.......................................... 6-194 TABLE 6.6.1-23. FISSILE MASS POSITION WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY..................................... 6-194 TABLE 6.6.1-24. FLOODING STUDY

SUMMARY

WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY ............................ 6-195 TABLE 6.6.1-25. ARRAY CONFIGURATION STUDY WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY ....................... 6-195 TABLE 6.6.1-26. HOMOGENEOUS FISSILE MASS SIZE - 1.25-WT.% 235U, STANDARD HAC ARRAY ....................................... 6-199 TABLE 6.6.1-27. HDPE CAVITY VOLUME FRACTION - 1.25-WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY ........... 6-199 TABLE 6.6.1-28. HETEROGENEOUS FISSILE MASS SIZE - 1.25-WT.% 235U, STANDARD HAC ARRAY ................................... 6-199 TABLE 6.6.1-29. FISSILE MASS POSITION - 1.25-WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY .............................. 6-199 TABLE 6.6.1-30. FLOODING STUDY

SUMMARY

- 1.25-WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY ...................... 6-200 TABLE 6.6.1-31. ARRAY CONFIGURATION STUDY - 1.25-WT.% 235U, HDPE CAVITY, STANDARD HAC ARRAY ................. 6-200 TABLE 6.6.2-1. 100-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY RESULTS ......................................................... 6-204 TABLE 6.6.2-2. 100-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY - FLOODING RESULTS ................................... 6-205 TABLE 6.6.2-3. 100-WT.% 235U HETEROGENEOUS EFFECTS HAC ARRAY STUDY RESULTS .................................................... 6-206 TABLE 6.6.2-4. 20-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY (CSI=0.7) RESULTS ....................................... 6-207 TABLE 6.6.2-5. 20-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY (CSI=1.0) RESULTS ....................................... 6-207 TABLE 6.6.2-6. 20-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY (CSI=0.7) - FLOODING RESULTS ................. 6-209 TABLE 6.6.2-7. 20-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY (CSI=1.0) - FLOODING RESULTS ................. 6-209 TABLE 6.6.2-8. 20-WT.% 235U HETEROGENEOUS EFFECTS HAC ARRAY STUDY (CSI=0.7) RESULTS .................................. 6-211 TABLE 6.6.2-9. 10-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY RESULTS ............................................................ 6-212 TABLE 6.6.2-10. 10-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY - FLOODING RESULTS ................................... 6-213 TABLE 6.6.2-11. 10-WT.% 235U HETEROGENEOUS EFFECTS HAC ARRAY STUDY RESULTS .................................................... 6-214 TABLE 6.6.2-12. 5-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY RESULTS ............................................................ 6-215 TABLE 6.6.2-13. 5-WT.% 235U 840 G235U HETEROGENEOUS EFFECTS HAC ARRAY STUDY RESULTS .................................. 6-216 TABLE 6.6.2-14. 5-WT.% 235U 800 G235U HETEROGENEOUS EFFECTS HAC ARRAY STUDY RESULTS .................................. 6-216 6-vi

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 TABLE 6.6.2-15. 5-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY - FLOODING RESULTS ...................................... 6-218 TABLE 6.6.3-1.

SUMMARY

OF LIMITING CASES FOR HAC PACKAGE ARRAY EVALUATION ......................................................... 6-219 TABLE 6.6.3-2. FILL PERCENTAGE SENSITIVITY OF THE FIVE-INCH PIPE CONTAINER - HAC PACKAGE ARRAY.................... 6-220 TABLE 6.6.3-3. U-235 MASS SENSITIVITY OF THE FIVE-INCH PIPE CONTAINER - HAC PACKAGE ARRAY ............................ 6-221 TABLE 6.6.3-4. ARRAY CONFIGURATION SENSITIVITY OF THE 5-INCH PIPE - U(100) HAC PACKAGE ARRAY .................... 6-224 TABLE 6.6.3-5. ARRAY CONFIGURATION SENSITIVITY OF THE 5-INCH PIPE CONTAINER - U(20) HAC PACKAGE ARRAY . 6-224 TABLE 6.6.3-6. ARRAY CONFIGURATION SENSITIVITY OF THE 5-INCH PIPE CONTAINER - U(10) HAC PACKAGE ARRAY . 6-224 TABLE 6.6.3-7. PARTIAL MODERATION DENSITY SENSITIVITY OF THE 5-INCH PIPE CONTAINER - HAC PACKAGE ARRAY 6-227 TABLE 6.6.3-8. PARTIAL FILL SENSITIVITY OF THE 5-INCH PIPE CONTAINER - HAC PACKAGE ARRAY ................................. 6-229 TABLE 6.6.3-9. FLOODING STUDY INCH PIPE U(100) HAC PACKAGE ARRAY ..................................................................... 6-231 TABLE 6.6.3-10. FLOODING STUDY INCH PIPE U(20) HAC PACKAGE ARRAY ..................................................................... 6-232 TABLE 6.6.3-11. FLOODING STUDY INCH PIPE U(10) HAC PACKAGE ARRAY ..................................................................... 6-233 TABLE 6.6.4-1.

SUMMARY

5-INCH PIPE HYDROGEN LIMITED CONTENT HAC ARRAY HOMOGENEOUS CRITICALITY EVALUATION

............................................................................................................................................................................................................ 6-236 TABLE 6.6.4-2. 5-INCH PIPE HYDROGEN LIMITED CONTENT 10 WT% U-METAL HAC ARRAY HETEROGENEOUS CRITICALITY EVALUATION .................................................................................................................................................................................... 6-238 TABLE 6.6.4-3. 5-INCH PIPE HYDROGEN LIMITED CONTENT 10 WT% UO2 HAC ARRAY HETEROGENEOUS CRITICALITY EVALUATION .................................................................................................................................................................................... 6-238 TABLE 6.6.4-4. 5-INCH PIPE HYDROGEN LIMITED CONTENT 20 WT% U-METAL HAC ARRAY HETEROGENEOUS CRITICALITY EVALUATION .................................................................................................................................................................................... 6-240 TABLE 6.6.4-5. HAC ARRAY 10-WT% U-METAL (CSI=1.4) FLOODING STUDY RESULTS ....................................................... 6-241 TABLE 6.6.5-1. EFFECT OF PIPE SPACING ON KEFF - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY ...................................... 6-243 TABLE 6.6.5-2. EFFECT OF REFLECTOR THICKNESS ON KEFF - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY .................... 6-243 TABLE 6.6.5-3. EFFECT OF URANIUM MASS ON KEFF - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY .................................. 6-243 TABLE 6.6.5-4. EFFECT OF FILL HEIGHT ON KEFF - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY........................................ 6-243 TABLE 6.6.5-5. EFFECT OF FLOODING CONFIGURATION ON KEFF - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY ............. 6-244 TABLE 6.6.5-6. EFFECT OF FILL HEIGHT ON KEFF FOR FLD3_0.0001 - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY ... 6-248 TABLE 6.6.5-7. EFFECT OF 5-INCH PIPE GROUP POSITIONING ON KEFF - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY .. 6-249 TABLE 6.6.5-8. EFFECT OF ARRAY CONFIGURATION ON KEFF - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY ................... 6-249 TABLE 6.6.5-9. EFFECT OF UF6 ON KEFF - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY ....................................................... 6-250 TABLE 6.6.5-10. EFFECT OF REFLECTOR THICKNESS ON KEFF - 2S, 100-WT.% U-235, HAC PACKAGE ARRAY .................. 6-251 TABLE 6.6.5-11. EFFECT OF URANIUM MASS ON KEFF - 2S, 100-WT.% U-235, HAC PACKAGE ARRAY ............................... 6-251 TABLE 6.6.5-12. EFFECT OF FILL HEIGHT ON KEFF - 2S, 100-WT.% U-235, HAC PACKAGE ARRAY ..................................... 6-251 TABLE 6.6.5-13. EFFECT OF FLOODING CONFIGURATION ON KEFF - 2S, 100-WT.% U-235, HAC PACKAGE ARRAY ........... 6-252 TABLE 6.6.5-14. EFFECT OF 5-INCH PIPE POSITIONING ON KEFF - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY ................ 6-255 TABLE 6.6.5-15. EFFECT OF ARRAY CONFIGURATION ON KEFF - 2S, 100-WT.% U-235, HAC PACKAGE ARRAY ................. 6-255 TABLE 6.6.5-16. EFFECT OF UF6 ON KEFF - 2S, 100-WT.% U-235, HAC PACKAGE ARRAY .................................................... 6-256 TABLE 6.6.5-17. EFFECT OF SPHERE SIZE (H/U-235) ON KEFF - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY ................ 6-257 TABLE 6.6.5-18. EFFECT OF URANIUM MASS ON KEFF - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY .................................. 6-257 TABLE 6.6.5-19. EFFECT OF FLOODING CONFIGURATION ON KEFF - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY ............. 6-258 TABLE 6.6.5-20. EFFECT OF H/U-235 ON KEFF FOR FLD1_1 - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY .................... 6-261 TABLE 6.6.5-21. EFFECT OF FLD1 ON KEFF FOR H/U-235 OF 650 - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY .......... 6-261 TABLE 6.6.5-22. EFFECT OF CYLINDER GROUP POSITIONING ON KEFF - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY ...... 6-263 TABLE 6.6.5-23. EFFECT OF ARRAY CONFIGURATION ON KEFF - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY ................... 6-263 TABLE 6.6.5-24. EFFECT OF UF6 ON KEFF - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY ....................................................... 6-264 TABLE 6.6.5-25. EFFECT OF SPHERE SIZE (H/U-235) ON KEFF - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY ................ 6-265 TABLE 6.6.5-26. EFFECT OF URANIUM MASS ON KEFF - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY .................................. 6-265 TABLE 6.6.5-27. EFFECT OF FLOODING CONFIGURATION ON KEFF - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY ............. 6-266 TABLE 6.6.5-28. EFFECT OF H/U-235 ON KEFF FOR FLD1_0.1 - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY ................ 6-269 TABLE 6.6.5-29. EFFECT OF CYLINDER GROUP POSITIONING ON KEFF - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY ...... 6-270 TABLE 6.6.5-30. EFFECT OF ARRAY CONFIGURATION ON KEFF - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY ................... 6-270 TABLE 6.6.5-31. EFFECT OF UF6 ON KEFF - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY ....................................................... 6-271 6-vii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 TABLE 6.6.6-1. CPVC COMPOUND HOMOGENEOUS RESULTS - HAC ARRAY............................................................................... 6-272 TABLE 6.6.6-2. BOUNDING CPVC COMPOUND CHLORINE AND DENSITY KEFF EVALUATION - HAC ARRAY ............................ 6-273 TABLE 6.6.6-4. BOUNDING URANIUM COMPOUND CLASS CASE

SUMMARY

................................................................................... 6-275 TABLE 6.6.6-5. URANIUM COMPOUNDS BOUNDED BY U3O8 CASE

SUMMARY

(CSI=1.4) .......................................................... 6-276 TABLE 6.6.6-6. HAC ARRAY 20-WT.% 235U U3O8 HOMOGENEOUS CASE

SUMMARY

(CSI=0.7) ............................................ 6-277 TABLE 6.6.6-7. HAC ARRAY HETEROGENEOUS CASE

SUMMARY

- UC 20-WT.% 235U (CSI=1.4) ......................................... 6-279 TABLE 6.6.6-8. HAC ARRAY HETEROGENEOUS CASE

SUMMARY

- U3O8 20-WT.% 235U (CSI=0.7) ..................................... 6-279 TABLE 6.6.6-9. HAC ARRAY 20-WT.% UC (CSI=1.4) FLOODING STUDY RESULTS .................................................................. 6-281 TABLE 6.6.6-10. HAC ARRAY 20-WT.% U3O8 (CSI=0.7) FLOODING STUDY RESULTS ........................................................... 6-281 TABLE 6.6.6-11. HCB STUDY RESULTS - HAC ARRAY .................................................................................................................... 6-283 TABLE 6.7-1. AIR TRANSPORT H/U-235 VARIATION RESULTS ..................................................................................................... 6-285 TABLE 6.7-2. AIR TRANSPORT WATER MODERATION RESULTS ..................................................................................................... 6-288 TABLE 6.7-3. AIR TRANSPORT HDPE DENSITY VARIATION RESULTS ........................................................................................... 6-290 TABLE 6.8.1-1.

SUMMARY

OF CRITICAL BENCHMARK EXPERIMENTS ............................................................................................ 6-294 TABLE 6.8.1-2.

SUMMARY

OF CRITICAL BENCHMARK EXPERIMENTS ............................................................................................ 6-295 TABLE 6.8.2-1. USL EQUATIONS AND AREA OF APPLICABILITY BY ANALYZED ENRICHMENT .................................................. 6-301 6-viii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 FIGURES FIGURE 6.3.1-1. VP-55 NCT MODEL TOP (LEFT) AND SIDE (RIGHT) VIEWS ................................................................................. 6-21 FIGURE 6.3.1-2. VP-55 HAC MODEL TOP (LEFT) AND SIDE (RIGHT) VIEWS................................................................................. 6-21 FIGURE 6.3.1-3. ANSI N14.1 1S CYLINDER (TOP) AND 2S CYLINDER (BOTTOM) ....................................................................... 6-22 FIGURE 6.3.1-4. TOP, SIDE VIEWS OF THE 1S CYLINDER GROUP ....................................................................................................... 6-23 FIGURE 6.3.1-5. TOP, SIDE VIEWS OF THE 2S CYLINDER GROUP ....................................................................................................... 6-23 FIGURE 6.3.1-6. TOP, SIDE VIEWS OF THREE 1S CYLINDERS, EACH IN A 5-INCH PIPE - HAC 100-WT.% U-235 ................. 6-24 FIGURE 6.3.1-7. TOP (LEFT) AND SIDE (RIGHT) VIEWS OF HCB MODEL........................................................................................ 6-25 FIGURE 6.3.4-1. FISSILE MASS GEOMETRY. HOMOGENEOUS (LEFT AND CENTER) AND HETEROGENEOUS (RIGHT). ............... 6-32 FIGURE 6.3.4-2. CAVITY REFLECTORS: WATER, HDPE, AND STEEL (LEFT TO RIGHT). ................................................................. 6-32 FIGURE 6.3.4-3. TOP (LEFT) AND SIDE VIEWS (RIGHT) OF THE DEFAULT HAC PACKAGE ARRAY FISSILE MASS POSITIONS. 6-33 FIGURE 6.3.4-4. TOP VIEW OF THE FOUR HAC FLOODING CONFIGURATIONS. ............................................................................... 6-33 FIGURE 6.3.4-5. THE 2X HIGH HAC PACKAGE ARRAY CONFIGURATIONS EXAMINED.................................................................... 6-34 FIGURE 6.3.4-6. 5-INCH PIPE CONTAINER 45% FULL IN A VP-55 WITH HAC DAMAGE ............................................................. 6-37 FIGURE 6.3.4-7. SIDE VIEW OF BOUNDING FISSILE POSITIONS FOR A 5-INCH PIPE PACKAGE ARRAY ........................................ 6-38 FIGURE 6.3.4-8. TOP VIEW OF BOUNDING FISSILE POSITIONS IN THE X-Y PLANE ......................................................................... 6-38 FIGURE 6.3.4-9. SINGLE PACKAGE 10 WT%235U DUAL PIPE GEOMETRY (LEFT - SIDE / RIGHT - TOP).................................. 6-39 FIGURE 6.3.4-10. HAC ARRAY 10 WT%235U DUAL PIPE GEOMETRY (LEFT - SIDE / RIGHT - TOP) ....................................... 6-40 FIGURE 6.3.4-11. HAC ARRAY 20 WT%235U SINGLE PIPE GEOMETRY (LEFT - SIDE / RIGHT - TOP) .................................... 6-40 FIGURE 6.3.4-12. TOP VIEW OF THE HAC FLOODING CONFIGURATIONS ......................................................................................... 6-44 FIGURE 6.3.4-13. TOP, SIDE VIEWS OF 1S CYLINDER-GROUP CONFIGURATION - SINGLE PACKAGE. ......................................... 6-45 FIGURE 6.3.4-14. TOP, SIDE VIEWS OF 1S CYLINDER GROUP RADIAL POSITION - SINGLE PACKAGE ........................................ 6-45 FIGURE 6.3.4-15. TOP, SIDE VIEWS OF 1S CYLINDER GROUP AXIAL POSITION CASE - SINGLE PACKAGE ................................. 6-45 FIGURE 6.3.4-16. THE DEFAULT 2S CYLINDER DISPLACEMENT - NCT PACKAGE ARRAY ........................................................... 6-46 FIGURE 6.3.4-17. THE RADIALLY CENTERED 2S CYLINDER-GROUP CASE - NCT PACKAGE ARRAY .......................................... 6-46 FIGURE 6.3.4-18. THE AXIALLY CENTERED 2S CYLINDER-GROUP CASE - NCT PACKAGE ARRAY ............................................. 6-47 FIGURE 6.3.4-19. THE CENTERED 2S CYLINDER-GROUP CASE - NCT PACKAGE ARRAY ............................................................. 6-47 FIGURE 6.3.4-20. VP-55 WITH HCB SINGLE PACKAGE GEOMETRY (TOP VIEW / SIDE VIEW) .................................................. 6-50 FIGURE 6.3.4-21. VP-55 WITH HCB HAC ARRAY GEOMETRY (TOP VIEW / SIDE VIEW) ........................................................... 6-50 FIGURE 6.4.1-1. STANDARD CONFIGURATION MODEL - SINGLE PACKAGE ...................................................................................... 6-52 FIGURE 6.4.1-2. HOMOGENEOUS FISSILE SHAPE - 100-WT.% 235U STANDARD SINGLE PACKAGE ............................................ 6-54 FIGURE 6.4.1-3. HETEROGENEOUS FISSILE SHAPE - 100-WT.% 235U STANDARD SINGLE PACKAGE ........................................ 6-55 FIGURE 6.4.1-4. BOUNDING PARTICLE RESULTS - 100-WT.% 235U STANDARD SINGLE PACKAGE ............................................ 6-55 FIGURE 6.4.1-5. HOMOGENEOUS FISSILE SHAPE WT.% 235U STANDARD SINGLE PACKAGE .............................................. 6-57 FIGURE 6.4.1-6. HETEROGENEOUS FISSILE SHAPE WT.% 235U STANDARD SINGLE PACKAGE ........................................... 6-58 FIGURE 6.4.1-7. HETEROGENEOUS BOUNDING PARTICLE WT.% 235U STANDARD SINGLE PACKAGE ............................... 6-58 FIGURE 6.4.1-8. HOMOGENEOUS FISSILE SHAPE WT.% 235U SINGLE PACKAGE ................................................................... 6-60 FIGURE 6.4.1-9. HETEROGENEOUS FISSILE SHAPE WT.% 235U STANDARD SINGLE PACKAGE ........................................... 6-61 FIGURE 6.4.1-10. HETEROGENEOUS BOUNDING PARTICLE WT.% 235U STANDARD SINGLE PACKAGE ............................ 6-61 FIGURE 6.4.1-11. HOMOGENEOUS FISSILE SHAPE WT.% 235U SINGLE STANDARD PACKAGE .............................................. 6-64 FIGURE 6.4.1-12. HETEROGENEOUS FISSILE SHAPE WT.% 235U STANDARD SINGLE PACKAGE ........................................... 6-64 FIGURE 6.4.1-13. HETEROGENEOUS FISSILE SHAPE WITH HDPE WT.% 235U STANDARD SINGLE PACKAGE ................... 6-65 FIGURE 6.4.1-14. BOUNDING PARTICLE RESULTS WT.% 235U STANDARD SINGLE PACKAGE............................................... 6-65 FIGURE 6.4.1-15. HOMOGENEOUS FISSILE SHAPE - 1.25-WT.% 235U STANDARD SINGLE PACKAGE ........................................ 6-68 FIGURE 6.4.1-16. HETEROGENEOUS FISSILE SHAPE - 1.25-WT.% 235U SINGLE STANDARD PACKAGE..................................... 6-68 FIGURE 6.4.1-17. HETEROGENEOUS FISSILE SHAPE WITH HDPE - 1.25-WT.% 235U STANDARD SINGLE PACKAGE ............. 6-69 FIGURE 6.4.1-18. HETEROGENEOUS BOUNDING PARTICLE - 1.25-WT.% 235U SINGLE STANDARD PACKAGE......................... 6-69 FIGURE 6.4.2-1. 100-WT.% 235U HYDROGEN LIMITED CONTENT SINGLE PACKAGE RESULTS ................................................... 6-70 FIGURE 6.4.2-2. 20-WT.% 235U HYDROGEN LIMITED CONTENT SINGLE PACKAGE RESULTS ...................................................... 6-71 FIGURE 6.4.2-3. 10-WT.% 235U HYDROGEN LIMITED CONTENT SINGLE PACKAGE RESULTS ...................................................... 6-72 FIGURE 6.4.2-4. 5-WT.% 235U HYDROGEN LIMITED CONTENT SINGLE PACKAGE RESULTS ........................................................ 6-73 FIGURE 6.4.2-5. 5-WT.% 235U PARTICLE SIZE STUDY HYDROGEN LIMITED CONTENT SINGLE PACKAGE ................................. 6-74 6-ix

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 FIGURE 6.4.3-1. FILL PERCENTAGE SENSITIVITY INCH PIPE SINGLE PACKAGE........................................................................ 6-76 FIGURE 6.4.3-2. PARTIAL FILL SENSITIVITY INCH PIPE SINGLE PACKAGE ................................................................................ 6-78 FIGURE 6.4.3-3: PARTIAL U-235 MASS SENSITIVITY - U(10) 5-INCH PIPE SINGLE PACKAGE ................................................... 6-79 FIGURE 6.4.4-1. 10 WT% 5-INCH PIPE HYDROGEN LIMITED CONTENT SINGLE PACKAGE RESULTS ......................................... 6-81 FIGURE 6.4.4-2. 20 WT% 5-INCH PIPE HYDROGEN LIMITED CONTENT SINGLE PACKAGE RESULTS ......................................... 6-81 FIGURE 6.4.5-1. EFFECT OF 5-INCH PIPE SPACING - 1S, 100-WT.% U-235, SINGLE PACKAGE ................................................ 6-84 FIGURE 6.4.5-2. EFFECT OF URANIUM MASS - 1S, 100-WT.% U-235, SINGLE PACKAGE .......................................................... 6-84 FIGURE 6.4.5-3. EFFECT OF 5-INCH PIPE FILL HEIGHT - 1S, 100-WT.% U-235, SINGLE PACKAGE ......................................... 6-85 FIGURE 6.4.5-4. EFFECT OF UF6 FISSILE SOLUTION - 1S, 100-WT.% U-235, SINGLE PACKAGE .............................................. 6-86 FIGURE 6.4.5-5. EFFECT OF CYLINDER FILL HEIGHT - 2S, 100-WT.% U-235, SINGLE PACKAGE ............................................. 6-88 FIGURE 6.4.5-6. EFFECT OF URANIUM MASS - 2S, 100-WT.% U-235, SINGLE PACKAGE .......................................................... 6-88 FIGURE 6.4.5-7. EFFECT OF UF6 FISSILE SOLUTION - 2S, 100-WT.% U-235, SINGLE PACKAGE .............................................. 6-90 FIGURE 6.4.5-8. EFFECT OF SPHERE RADIUS - 1S, 20-WT.% U-235, SINGLE PACKAGE ............................................................. 6-92 FIGURE 6.4.5-9. EFFECT OF URANIUM MASS - 1S, 20-WT.% U-235, SINGLE PACKAGE ............................................................. 6-92 FIGURE 6.4.5-10. EFFECT OF UF6 - 1S, 20-WT.% U-235, SINGLE PACKAGE ................................................................................ 6-94 FIGURE 6.4.5-11. EFFECT OF SPHERE SIZE - 2S, 20-WT.% U-235, SINGLE PACKAGE ................................................................ 6-96 FIGURE 6.4.5-12. EFFECT OF URANIUM MASS - 2S, 20-WT.% U-235, SINGLE PACKAGE .......................................................... 6-96 FIGURE 6.4.5-13. EFFECT OF UF6 - 2S, 20-WT.% U-235, SINGLE PACKAGE ................................................................................ 6-98 FIGURE 6.4.6-1. SINGLE PACKAGE VOLUME FRACTION UC VS. KEFF ................................................................................................... 6-99 FIGURE 6.5-1. TOP AND SIDE VIEWS OF 5N = 252 NCT PACKAGE ARRAY .................................................................................. 6-101 FIGURE 6.5-2. TOP AND SIDE VIEWS OF 5N = 360 NCT PACKAGE ARRAY .................................................................................. 6-101 FIGURE 6.5.1-1. HOMOGENEOUS FISSILE SHAPE - 100-WT.% 235U STANDARD NCT ARRAY ................................................. 6-104 FIGURE 6.5.1-2. HETEROGENEOUS PARTICLE RESULTS - DRY CAVITY, 100-WT.% 235U STANDARD NCT ARRAY ............. 6-105 FIGURE 6.5.1-3. BOUNDING PARTICLE RESULTS - DRY CAVITY, 100-WT.% 235U STANDARD NCT ARRAY ......................... 6-105 FIGURE 6.5.1-4. ARRAY CONFIGURATION STUDY - HDPE CAVITY, 100-WT.% 235U STANDARD NCT ARRAY .................... 6-106 FIGURE 6.5.1-5. HOMOGENEOUS FISSILE MASS - DRY CAVITY, 20-WT.% 235U STANDARD NCT ARRAY .............................. 6-109 FIGURE 6.5.1-6. HOMOGENEOUS FISSILE MASS - HDPE CAVITY, 20-WT.% 235U STANDARD NCT ARRAY ......................... 6-110 FIGURE 6.5.1-7. HETEROGENEOUS PARTICLE - 445 G235U, DRY CAVITY, 20-WT.% 235U STANDARD NCT ARRAY ........... 6-110 FIGURE 6.5.1-8. BOUNDING PARTICLE RESULTS - 445 G235U, DRY CAVITY, 20-WT.% 235U STANDARD NCT ARRAY....... 6-111 FIGURE 6.5.1-9. ARRAY CONFIGURATION STUDY - DRY CAVITY, 20-WT.% 235U STANDARD NCT ARRAY ........................... 6-111 FIGURE 6.5.1-10. HOMOGENEOUS FISSILE MASS SIZE - DRY CAVITY, 10-WT.% 235U STANDARD NCT ARRAY .................. 6-114 FIGURE 6.5.1-11. HOMOGENEOUS FISSILE MASS SIZE - HDPE CAVITY, 10-WT.% 235U STANDARD NCT ARRAY .............. 6-115 FIGURE 6.5.1-12. HETEROGENEOUS PARTICLE RESULTS - 505 G235U, DRY CAVITY, 10-WT.% STANDARD NCT ARRAY . 6-115 FIGURE 6.5.1-13. HETEROGENEOUS BOUNDING PARTICLE- 505 G235U, DRY CAVITY, 10-WT.% 235U NCT ARRAY .......... 6-116 FIGURE 6.5.1-14. ARRAY CONFIGURATION STUDY - DRY CAVITY, 10-WT.% 235U NCT ARRAY ............................................. 6-116 FIGURE 6.5.1-15. HOMOGENEOUS FISSILE MASS- 630 G235U, DRY CAVITY, 5-WT.% 235U STANDARD NCT ARRAY ......... 6-120 FIGURE 6.5.1-16. HOMOGENEOUS FISSILE MASS- 630 G235U, HDPE CAVITY, 5-WT.% 235U STANDARD NCT ARRAY ..... 6-120 FIGURE 6.5.1-17. HETEROGENEOUS PARTICLE RESULTS - 630 G235U, DRY CAVITY, 5-WT.% STANDARD NCT ARRAY .... 6-121 FIGURE 6.5.1-18. HETEROGENEOUS PARTICLE RESULTS - 610 G235U, DRY CAVITY, 5-WT.% STANDARD NCT ARRAY .... 6-121 FIGURE 6.5.1-19. BOUNDING PARTICLE RESULTS - 610 G235U, 5-WT.% 235U STANDARD NCT ARRAY .............................. 6-122 FIGURE 6.5.1-20. ARRAY CONFIGURATION STUDY WT.% 235U STANDARD NCT ARRAY ................................................... 6-122 FIGURE 6.5.1-21. HOMOGENEOUS FISSILE MASS SIZE - 1.25-WT.% 235U STANDARD NCT ARRAY ...................................... 6-125 FIGURE 6.5.1-22. HETEROGENEOUS PARTICLE RESULTS - 2000 G235U, DRY CAVITY, STANDARD NCT ARRAY ................. 6-126 FIGURE 6.5.1-23. HETEROGENEOUS PARTICLE - 1650 G235U, DRY CAVITY, 1.25-WT.% STANDARD NCT ARRAY............ 6-126 FIGURE 6.5.1-24. BOUNDING PARTICLE RESULTS - 1650 G235U, DRY CAVITY, 1.25-WT.% STANDARD NCT ARRAY ....... 6-127 FIGURE 6.5.1-25. ARRAY CONFIGURATION STUDY - 1.25-WT.% 235U STANDARD NCT ARRAY............................................. 6-127 FIGURE 6.5.2-1. 100-WT.% 235U HYDROGEN-LIMITED CONTENT NCT ARRAY RESULTS ........................................................ 6-129 FIGURE 6.5.2-2. 100-WT.% 235U NON-HYDROGENOUS MODERATOR NCT ARRAY STUDY RESULTS ..................................... 6-131 FIGURE 6.5.2-3. 20-WT.% 235U HYDROGEN-LIMITED CONTENT NCT ARRAY RESULTS .......................................................... 6-132 FIGURE 6.5.2-4. 20-WT.% 235U NON-HYDROGENOUS MODERATOR NCT ARRAY STUDY RESULTS ....................................... 6-134 FIGURE 6.5.2-5. 10-WT.% 235U HYDROGEN-LIMITED CONTENT NCT ARRAY RESULTS .......................................................... 6-135 FIGURE 6.5.2-6. 10-WT.% 235U NON-HYDROGENOUS MODERATOR NCT ARRAY STUDY RESULTS ....................................... 6-137 6-x

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 FIGURE 6.5.2-7. 5-WT.% 235U HYDROGEN-LIMITED CONTENT NCT ARRAY RESULTS ............................................................. 6-138 FIGURE 6.5.2-8. 5-WT.% 235U NON-HYDROGENOUS MODERATOR NCT ARRAY STUDY RESULTS .......................................... 6-140 FIGURE 6.5.3-1. VARIATION OF FILL SENSITIVITY INCH PIPE NCT PACKAGE ARRAY ......................................................... 6-142 FIGURE 6.5.3-2. VARIATION OF U-235 MASS SENSITIVITY - U(100) 5-INCH PIPE NCT PACKAGE ARRAY .......................... 6-144 FIGURE 6.5.3-3. VARIATION OF U-235 MASS SENSITIVITY - U(20) 5-INCH PIPE NCT PACKAGE ARRAY ............................. 6-144 FIGURE 6.5.3-4. VARIATION OF U-235 MASS SENSITIVITY - U(10) 5-INCH PIPE NCT PACKAGE ARRAY ............................. 6-145 FIGURE 6.5.3-5. ARRAY CONFIGURATION SENSITIVITY - U(100) NCT PACKAGE ARRAY ......................................................... 6-147 FIGURE 6.5.3-6. ARRAY CONFIGURATION SENSITIVITY - U(20) NCT PACKAGE ARRAY ............................................................ 6-147 FIGURE 6.5.3-7. ARRAY CONFIGURATION SENSITIVITY - U(10) NCT PACKAGE ARRAY ............................................................ 6-148 FIGURE 6.5.3-8. PARTIAL FILL SENSITIVITY INCH PIPE NCT PACKAGE ARRAY ................................................................... 6-149 FIGURE 6.5.4-1. 10 WT% 5-INCH PIPE HYDROGEN LIMITED CONTENT NCT ARRAY RESULTS ............................................... 6-151 FIGURE 6.5.4-2. 20 WT% 5-INCH PIPE HYDROGEN LIMITED CONTENT NCT ARRAY RESULTS ............................................... 6-151 FIGURE 6.5.5-1. EFFECT OF CYLINDER SPACING - 1S, 100-WT.% U-235, NCT PACKAGE ARRAY ........................................ 6-153 FIGURE 6.5.5-2. EFFECT OF REFLECTOR THICKNESS - 1S, 100-WT.% U-235, NCT PACKAGE ARRAY................................. 6-154 FIGURE 6.5.5-3. EFFECT OF URANIUM MASS - 1S, 100-WT.% U-235, NCT PACKAGE ARRAY .............................................. 6-154 FIGURE 6.5.5-4. EFFECT OF FILL HEIGHT - 1S, 100-WT.% U-235, NCT PACKAGE ARRAY .................................................... 6-155 FIGURE 6.5.5-5. EFFECT OF UF6 ON KEFF - 1S, 100-WT.% U-235, NCT PACKAGE ARRAY ...................................................... 6-156 FIGURE 6.5.5-6. EFFECT OF REFLECTOR THICKNESS - 2S, 100-WT.% U-235, NCT PACKAGE ARRAY................................. 6-158 FIGURE 6.5.5-7. EFFECT OF URANIUM MASS - 2S, 100-WT.% U-235, NCT PACKAGE ARRAY .............................................. 6-158 FIGURE 6.5.5-8. EFFECT OF FILL HEIGHT - 2S, 100-WT.% U-235, NCT PACKAGE ARRAY .................................................... 6-159 FIGURE 6.5.5-9. EFFECT OF UF6 ON KEFF - 2S, 100-WT.% U-235, NCT PACKAGE ARRAY ...................................................... 6-160 FIGURE 6.5.5-10. EFFECT OF CYLINDER SPACING - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY ........................................ 6-162 FIGURE 6.5.5-11. EFFECT OF REFLECTOR THICKNESS - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY................................. 6-162 FIGURE 6.5.5-12. EFFECT OF URANIUM MASS - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY .............................................. 6-163 FIGURE 6.5.5-13. EFFECT OF FILL HEIGHT - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY .................................................... 6-163 FIGURE 6.5.5-14. EFFECT OF UF6 ON KEFF - 1S, 20-WT.% U-235, NCT PACKAGE ARRAY ...................................................... 6-165 FIGURE 6.5.5-15. EFFECT OF CYLINDER SPACING - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY ........................................ 6-167 FIGURE 6.5.5-16. EFFECT OF REFLECTOR THICKNESS - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY................................. 6-167 FIGURE 6.5.5-17. EFFECT OF URANIUM MASS - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY .............................................. 6-168 FIGURE 6.5.5-18. EFFECT OF FILL HEIGHT - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY .................................................... 6-168 FIGURE 6.5.5-19. EFFECT OF UF6 ON KEFF - 2S, 20-WT.% U-235, NCT PACKAGE ARRAY ...................................................... 6-170 FIGURE 6.5.6-1. UC VOLUME FRACTION VS. KEFF FOR NOMINAL HCB COMPOUNDS - NCT ARRAY ......................................... 6-171 FIGURE 6.5.6-2. CPVC COMPOUND ANALYSIS CHLORINE WT.% VS. KEFF - NCT ARRAY ............................................................ 6-172 FIGURE 6.5.6-3. NCT ARRAY VOLUME FRACTION UC VS. KEFF......................................................................................................... 6-173 FIGURE 6.6-1. TOP AND SIDE VIEWS OF 2N = 72 HAC PACKAGE ARRAY ..................................................................................... 6-175 FIGURE 6.6-2. TOP AND SIDE VIEWS OF 2N = 105 HAC PACKAGE ARRAY .................................................................................. 6-176 FIGURE 6.6-3. TOP AND SIDE VIEWS OF 2N = 144 HAC PACKAGE ARRAY .................................................................................. 6-176 FIGURE 6.6.1-1. HOMOGENEOUS FISSILE MASS - HDPE CAVITY, 100-WT.% 235U, STANDARD HAC ARRAY...................... 6-180 FIGURE 6.6.1-2. HOMOGENEOUS FISSILE MASS - DRY CAVITY, 100-WT.% 235U STANDARD HAC ARRAY ........................... 6-180 FIGURE 6.6.1-3. HETEROGENEOUS PARTICLES - 360 G235U, DRY CAVITY, 100-WT.% 235U STANDARD HAC ARRAY....... 6-181 FIGURE 6.6.1-4. BOUNDING PARTICLE RESULTS - 360 G235U, DRY CAVITY, 100-WT.% 235U STANDARD HAC ARRAY .... 6-181 FIGURE 6.6.1-5. FLOODING STUDY - 360 G235U, HDPE CAVITY, 100-WT.% 235U STANDARD HAC ARRAY ....................... 6-182 FIGURE 6.6.1-6. ARRAY CONFIGURATION STUDY - HDPE CAVITY, 100-WT.% 235U STANDARD HAC ARRAY .................... 6-182 FIGURE 6.6.1-7. HOMOGENEOUS FISSILE SHAPE WT.% 235U STANDARD HAC ARRAY .................................................... 6-185 FIGURE 6.6.1-8. HETEROGENEOUS PARTICLE RESULTS - DRY CAVITY, 20-WT.% 235U STANDARD HAC ARRAY ................ 6-186 FIGURE 6.6.1-9. BOUNDING PARTICLE RESULTS - DRY CAVITY, 20-WT.% 235U STANDARD HAC ARRAY ............................ 6-186 FIGURE 6.6.1-10. FLOODING STUDY - HDPE CAVITY, 20-WT.% 235U STANDARD HAC ARRAY............................................. 6-187 FIGURE 6.6.1-11. ARRAY CONFIGURATION STUDY - HDPE CAVITY, 20-WT.% 235U STANDARD HAC ARRAY .................... 6-187 FIGURE 6.6.1-12. HOMOGENEOUS FISSILE SHAPE WT.% 235U STANDARD HAC ARRAY ................................................. 6-190 FIGURE 6.6.1-13. HETEROGENEOUS PARTICLE RESULTS - DRY CAVITY, 10-WT.% 235U STANDARD HAC ARRAY ............. 6-191 FIGURE 6.6.1-14. BOUNDING PARTICLE RESULTS - DRY CAVITY, 10-WT.% 235U STANDARD HAC ARRAY ......................... 6-191 FIGURE 6.6.1-15. FLOODING STUDY - HDPE CAVITY, 10-WT.% 235U STANDARD HAC ARRAY............................................. 6-192 6-xi

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 FIGURE 6.6.1-16. ARRAY CONFIGURATION STUDY - HDPE CAVITY, 10-WT.% 235U STANDARD HAC ARRAY .................... 6-192 FIGURE 6.6.1-17. HOMOGENEOUS FISSILE SHAPE WT.% 235U STANDARD HAC ARRAY .................................................... 6-195 FIGURE 6.6.1-18. HETEROGENEOUS PARTICLE RESULTS - DRY CAVITY, 5-WT.% 235U STANDARD HAC ARRAY ................ 6-196 FIGURE 6.6.1-19. BOUNDING PARTICLE RESULTS - DRY CAVITY, 5-WT.% 235U STANDARD HAC ARRAY ............................ 6-196 FIGURE 6.6.1-20. FLOODING STUDY WT.% 235U STANDARD HAC ARRAY ............................................................................ 6-197 FIGURE 6.6.1-21. ARRAY CONFIGURATION STUDY WT.% 235U STANDARD HAC ARRAY ................................................... 6-197 FIGURE 6.6.1-22. HOMOGENEOUS FISSILE SHAPE - 1.25-WT.% 235U STANDARD HAC ARRAY ............................................. 6-200 FIGURE 6.6.1-23. HETEROGENEOUS PARTICLE RESULTS - DRY CAVITY, 1.25-WT.% 235U STANDARD HAC ARRAY.......... 6-201 FIGURE 6.6.1-24. BOUNDING PARTICLE RESULTS - DRY CAVITY, 1.25-WT.% 235U STANDARD HAC ARRAY...................... 6-201 FIGURE 6.6.1-25. FLOODING STUDY -1.25-WT.% 235U STANDARD HAC ARRAY ...................................................................... 6-202 FIGURE 6.6.1-26. ARRAY CONFIGURATION STUDY - 1.25-WT.% 235U STANDARD HAC ARRAY ............................................ 6-202 FIGURE 6.6.2-1. 100-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY RESULTS........................................................ 6-204 FIGURE 6.6.2-2. 100-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY - FLOODING RESULTS.................................. 6-205 FIGURE 6.6.2-3. 100-WT.% 235U HETEROGENEOUS EFFECTS HAC ARRAY STUDY RESULTS .................................................. 6-206 FIGURE 6.6.2-4. 20-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY (CSI=0.7) RESULTS ...................................... 6-208 FIGURE 6.6.2-5. 20-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY (CSI=1.0) RESULTS ...................................... 6-208 FIGURE 6.6.2-6. 20-WT.% 235U HYDROGEN-LIMITED HAC ARRAY (CSI=0.7) - 605 G235U FLOODING RESULTS ............. 6-210 FIGURE 6.6.2-7. 20-WT.% 235U HYDROGEN-LIMITED HAC ARRAY (CSI=1.0) - 640 G235U FLOODING RESULTS ............. 6-210 FIGURE 6.6.2-8. 20-WT.% 235U HETEROGENEOUS EFFECTS HAC ARRAY STUDY (CSI=0.7) RESULTS................................. 6-211 FIGURE 6.6.2-9. 10-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY RESULTS .......................................................... 6-212 FIGURE 6.6.2-10. 10-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY - FLOODING RESULTS.................................. 6-213 FIGURE 6.6.2-11. 10-WT.% 235U HETEROGENEOUS EFFECTS HAC ARRAY STUDY RESULTS .................................................. 6-214 FIGURE 6.6.2-12. 5-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY RESULTS .......................................................... 6-215 FIGURE 6.6.2-13. 5-WT.% 235U 800 G235U HETEROGENEOUS EFFECTS HAC ARRAY STUDY RESULTS ................................ 6-217 FIGURE 6.6.2-14. 5-WT.% 235U HYDROGEN-LIMITED CONTENT HAC ARRAY - FLOODING RESULTS .................................... 6-218 FIGURE 6.6.3-1. VARIATION OF FILL SENSITIVITY - HAC PACKAGE ARRAY ................................................................................. 6-220 FIGURE 6.6.3-2. VARIATION OF U-235 MASS SENSITIVITY - U(100) HAC PACKAGE ARRAY.................................................. 6-222 FIGURE 6.6.3-3. VARIATION OF U-235 MASS SENSITIVITY - U(20) HAC PACKAGE ARRAY .................................................... 6-222 FIGURE 6.6.3-4. VARIATION OF U-235 MASS SENSITIVITY - U(10) HAC PACKAGE ARRAY .................................................... 6-223 FIGURE 6.6.3-5. ARRAY CONFIGURATION SENSITIVITY - U(100) HAC PACKAGE ARRAY ......................................................... 6-225 FIGURE 6.6.3-6. ARRAY CONFIGURATION SENSITIVITY - U(20) HAC PACKAGE ARRAY ............................................................ 6-225 FIGURE 6.6.3-7. ARRAY CONFIGURATION SENSITIVITY - U(10) HAC PACKAGE ARRAY ............................................................ 6-226 FIGURE 6.6.3-8. PARTIAL MODERATION DENSITY SENSITIVITY - HAC PACKAGE ARRAY .......................................................... 6-227 FIGURE 6.6.3-9. PARTIAL FILL SENSITIVITY - HAC PACKAGE ARRAY ........................................................................................... 6-230 FIGURE 6.6.3-10. FLOODING STUDY INCH PIPE U(100) HAC PACKAGE ARRAY ................................................................. 6-234 FIGURE 6.6.3-11. FLOODING STUDY INCH PIPE U(20) HAC PACKAGE ARRAY.................................................................... 6-234 FIGURE 6.6.3-12. FLOODING STUDY INCH PIPE U(10) HAC PACKAGE ARRAY.................................................................... 6-235 FIGURE 6.6.4-1. 10 WT% 5-INCH PIPE HYDROGEN LIMITED CONTENT HAC ARRAY HOMOGENEOUS RESULTS .................. 6-237 FIGURE 6.6.4-2. 20 WT% 5-INCH PIPE HYDROGEN LIMITED CONTENT HAC ARRAY HOMOGENEOUS RESULTS .................. 6-237 FIGURE 6.6.4-3. 10 WT% U-METAL 5-INCH PIPE HYDROGEN LIMITED CONTENT HAC ARRAY HETEROGENEOUS RESULTS.... 6-239 FIGURE 6.6.4-4. 10 WT% UO2 5-INCH PIPE HYDROGEN LIMITED CONTENT HAC ARRAY HETEROGENEOUS RESULTS ..... 6-239 FIGURE 6.6.4-5. 20 WT% U-METAL 5-INCH PIPE HYDROGEN LIMITED CONTENT HAC ARRAY HETEROGENEOUS RESULTS.... 6-240 FIGURE 6.6.4-6. 10 WT% 5-INCH PIPE HYDROGEN LIMITED CONTENT HAC ARRAY FLOODING STUDY RESULTS .............. 6-241 FIGURE 6.6.5-1. EFFECT OF PIPE SPACING - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY .................................................. 6-245 FIGURE 6.6.5-2. EFFECT OF REFLECTOR THICKNESS - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY ................................ 6-245 FIGURE 6.6.5-3. EFFECT OF URANIUM MASS - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY .............................................. 6-246 FIGURE 6.6.5-4. EFFECT OF FILL HEIGHT - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY.................................................... 6-246 FIGURE 6.6.5-5. EFFECT OF FLOODING CONFIGURATION - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY ......................... 6-247 FIGURE 6.6.5-6. EFFECT OF FILL HEIGHT VS KEFF FOR FLD3_0.0001 - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY ... 6-248 FIGURE 6.6.5-7. EFFECT OF UF6 ON KEFF - 1S, 100-WT.% U-235, HAC PACKAGE ARRAY ...................................................... 6-250 6-xii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 FIGURE 6.6.5-8. EFFECT OF REFLECTOR THICKNESS - 2S, 100-WT.% U-235, HAC PACKAGE ARRAY ................................ 6-253 FIGURE 6.6.5-9. EFFECT OF URANIUM MASS - 2S, 100-WT.% U-235, HAC PACKAGE ARRAY .............................................. 6-253 FIGURE 6.6.5-10. EFFECT OF FILL HEIGHT - 2S, 100-WT.% U-235, HAC PACKAGE ARRAY ................................................. 6-254 FIGURE 6.6.5-11. EFFECT OF FLOODING CONFIGURATIONS - 2S, 100-WT.% U-235, HAC PACKAGE ARRAY ..................... 6-254 FIGURE 6.6.5-12. EFFECT OF UF6 ON KEFF - 2S, 100-WT.% U-235, HAC PACKAGE ARRAY ................................................... 6-256 FIGURE 6.6.5-13. EFFECT OF SPHERE SIZE (H/U-235) - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY ............................ 6-259 FIGURE 6.6.5-14. EFFECT OF URANIUM MASS - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY .............................................. 6-259 FIGURE 6.6.5-15. EFFECT OF FLOODING CONFIGURATION - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY ......................... 6-260 FIGURE 6.6.5-16. EFFECT OF SPHERE SIZE (H/U-235) FOR FLD1_1 - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY .... 6-262 FIGURE 6.6.5-17. EFFECT OF FLD1 FOR H/U-235 OF 650 - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY ...................... 6-262 FIGURE 6.6.5-18. EFFECT OF UF6 ON KEFF - 1S, 20-WT.% U-235, HAC PACKAGE ARRAY ...................................................... 6-264 FIGURE 6.6.5-19. EFFECT OF SPHERE SIZE (H/U-235) - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY ............................ 6-267 FIGURE 6.6.5-20. EFFECT OF URANIUM MASS - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY .............................................. 6-267 FIGURE 6.6.5-21. EFFECT OF FLOODING CONFIGURATION - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY ......................... 6-268 FIGURE 6.6.5-22. EFFECT OF SPHERE SIZE (H/U-235) FOR FLD1_1 - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY .... 6-269 FIGURE 6.6.5-23. EFFECT OF UF6 ON KEFF - 2S, 20-WT.% U-235, HAC PACKAGE ARRAY ...................................................... 6-271 FIGURE 6.6.6-1. UC VOLUME FRACTION VS. KEFF FOR NOMINAL CPVC COMPOUNDS - HAC ARRAY ....................................... 6-272 FIGURE 6.6.6-2. CPVC COMPOUND CHLORINE PERCENTAGE AND DENSITY VS. KEFF - HAC ARRAY ........................................ 6-273 FIGURE 6.6.6-3. VOLUME FRACTION OF BOUNDING URANIUM COMPOUNDS VS. KEFF .................................................................. 6-275 FIGURE 6.6.6-4. COMPARISON OF UF4 AND UO3 WITH U3O8 VS. KEFF - CSI=1.4......................................................................... 6-277 FIGURE 6.6.6-5. HAC ARRAY HOMOGENEOUS VOLUME FRACTION U3O8 VS. KEFF - CSI=0.7 .................................................... 6-278 FIGURE 6.6.6-6. HAC ARRAY HETEROGENEOUS VOLUME FRACTION UC VS. KEFF ........................................................................ 6-280 FIGURE 6.6.6-7. HAC ARRAY HETEROGENEOUS VOLUME FRACTION U3O8 VS. KEFF .................................................................... 6-280 FIGURE 6.6.6-8. FLOODING STUDY UC (CSI=1.4) FLOODING VOLUME FRACTION VS. KEFF ....................................................... 6-282 FIGURE 6.6.6-9. FLOODING STUDY U3O8 (CSI=0.7) FLOODING VOLUME FRACTION VS. KEFF ................................................... 6-282 FIGURE 6.7-1. AIR TRANSPORT H/U-235 CURVE FOR EACH ENRICHMENT AND MASS LIMIT ................................................. 6-286 FIGURE 6.7-2. AIR TRANSPORT H/U-235 CURVES FOR MASS LIMIT DETERMINATIONS OF EACH ENRICHMENT ................. 6-287 FIGURE 6.7-3. AIR TRANSPORT WATER MODERATION RESULTS.................................................................................................... 6-289 FIGURE 6.7-4. AIR TRANSPORT HDPE DENSITY RESULTS .............................................................................................................. 6-291 FIGURE 6.8.2-1. USLSTATS TREND PLOT FOR 100 WT%. ............................................................................................................ 6-301 FIGURE 6.8.2-2. USLSTATS TREND PLOT FOR 20 WT%. .............................................................................................................. 6-302 FIGURE 6.8.2-3. USLSTATS TREND PLOT FOR 10 WT%. .............................................................................................................. 6-302 FIGURE 6.8.2-4. USLSTATS TREND PLOT FOR 5 WT%. ................................................................................................................. 6-303 FIGURE 6.8.2-5. USLSTATS TREND PLOT FOR 1.25 WT%. ........................................................................................................... 6-303 FIGURE 6.8.2-6. USLSTATS TREND PLOT FOR LOW H/X 10 WT% (5IP) ................................................................................. 6-304 FIGURE 6.8.2-7. USLSTATS TREND PLOT FOR EALF 20 WT% (HCB) ...................................................................................... 6-304 6-xiii

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6 CRITICALITY EVALUATION 6.1 Description of the Criticality Design 6.1.1 Design Features The full description of the Versa-Pac Shipping Container is in Section 1.2. The description here is limited to those features of the Versa-Pac that are relevant to criticality safety.

The Versa-Pac exists in two functionally identical but distinct versions consisting of the 55-gallon version (VP-55) and the 110-gallon version (VP-110). The VP-55 and VP-110 consist of a 55-gallon drum or 110-gallon drum exterior, respectively, surrounding the internal support structure that is primarily credited with all structural and thermal performance of the package in addition to housing the contents. The internal support structure and exterior structure, including their respective closures, provide two barriers to prevent the dispersion of the contents and water inleakage. An illustration of the packaging is provided in Figure 1-1 with the SCALE models provided in Section 6.3.1.

The Versa-Pac does not use any neutron moderators or absorbers. However, minimum thicknesses of continuous sheet and plate carbon steel (e.g., inner container, inner/outer liner, drum lid, body, and bottom, including top and bottom reinforcing plates) are modeled in the analysis. Discrete carbon steel consisting of the vertical stiffeners, flanges, angles, and bars are not modeled. Also not modeled are the flange ring interfaces with the flange. These are modeled assuming a continuous thickness of the flange material.

6.1.1.1 Versa-Pac Confinement Criticality control of the Versa-Pac relies on control of the inner container diameter, the vessel-to-vessel spacing provided by the drum, and the number of packages that may be shipped together.

The confinement boundary of the package is defined as the inner container with its associated welds, containment gasket, inner container blind flanges, and reinforcing ring.

6.1.1.2 5-inch Pipe The single and dual 5-inch pipe configurations of the Versa-Pac feature at least one 5-inch diameter steel pipe container located inside the inner container for the transport of greater quantities of U-235. For this configuration, the 5-inch pipe is the confinement boundary for the fissile contents. No credit is taken for the positioning of the 5-inch pipe in the package. In Section 2.7.8, it is demonstrated that the 5-inch pipe will not leak its contents post-HAC and retains fissile confinement.

6.1.1.3 1S/2S UF6 Cylinders For the 1S/2S UF6 cylinder content configuration, the structural integrity of the 1S/2S cylinder and valve is credited for its confinement of the fissile material for NCT. Water in-leakage is considered but no fissile material escapes the 1S/2S cylinders for NCT. All 1S/2S cylinder contents in the Versa-Pac must be ANSI N14.1-compliant [1]. Under HAC, all 1S/2S cylinders are conservatively assumed to fail and confinement then becomes the inner container wall of the Versa-Pac or the 5-inch pipe, depending on the U-235 enrichment of the contents.

6-1

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.1.1.4 High-Capacity Basket The High-Capacity Basket (HCB) consists of an aluminum structure that holds two Chlorinated Polyvinyl Chloride (CPVC) neutron moderator pipes and a CPVC separator plate. The rest of the space in the HCB is filled with thermal insulation. CPVC was chosen for its Hydrogen and Chlorine content, as the scattering with Hydrogen and neutron capture in Chlorine reduce cross talk, thus, system reactivity. Additionally, CPVC has a higher allowable temperature and ability to retain Hydrogen and Chlorine at elevated temperatures.

Each moderator pipe can accommodate one 5-inch pipe for a total of two (2) 5-inch pipes per HCB and the VP-55 can accommodate one HCB, thus, two (2) 5-inch pipes per VP-55. The HCB maintains positioning of the two 5-inch pipes in one package and between packages in an array.

The structural and thermal integrity of the HCB under HAC is credited such that it resists deformation, maintaining positioning of the 5-inch pipes, and retains its Hydrogen and Chlorine content post-HAC fire. The HCBs structural and thermal performance are demonstrated in Sections 2.12.3 and 3.5.4.

6-2

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.1.2 Summary Table of Criticality Evaluation As indicated in Section 6.3, the NCT and HAC configurations evaluated in this analysis were conservatively constructed based on the VP-55 to bound both the VP-55 and VP-110. While text throughout the SAR chapter may only explicitly reference the VP-55 or VP-110, the criticality analyses apply to, and bound, both Versa-Pac variants.

6.1.2.1 Standard Configuration Table 6.1.2-1 provides a summary of the results of the limiting cases from the criticality safety analysis that produced the additional enrichment level mass limits presented in Table 6.2.1-1. All results are less than their respective USLs. The USLs are calculated and presented in Section 6.1.2.7.

Table 6.1.2-1. Summary of the Standard Configuration Analysis 235 235 U Enrichment U Mass Array keff + 2 Reference (wt.%) (g) Size Single Package 100 360 -- 0.92927 Table 6.4.1-1 20 445 -- 0.92660 Table 6.4.1-5 10 505 -- 0.91766 Table 6.4.1-9 5 610 -- 0.90726 Table 6.4.1-15 1.25 1650 -- 0.86759 Table 6.4.1-20 NCT Package Array 100 360 252 0.93467 Table 6.5.1-5 20 445 252 0.94006 Table 6.5.1-6 10 505 252 0.93761 Table 6.5.1-12 5 610 252 0.93709 Table 6.5.1-22 1.25 1650 252 0.93844 Table 6.5.1-28 HAC Package Array 100 360 105 0.93743 Table 6.6.1-1 20 445 105 0.93651 Table 6.6.1-13 10 505 105 0.92851 Table 6.6.1-14 5 610 105 0.91936 Table 6.6.1-24 1.25 1650 105 0.92750 Table 6.6.1-31 6-3

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.1.2.2 Hydrogen-Limited Contents Including TRISO Fuels Table 6.1.2-2 provides a summary of the results of the hydrogen-limited content criticality safety analysis. These cases correspond to the limits presented in Table 6.2.2-1. See the referenced tables for the full configuration of the maximum keff listed for each enrichment.

Table 6.1.2-2. Summary Table of Hydrogen-Limited Criticality Evaluation 235 235 U Enrichment U Mass Array Size keff + 2 Reference (wt.%) (g)

Single Package 100 515 -- 0.90699 Table 6.4.2-1 20 635 -- 0.90502 Table 6.4.2-2 10 685 -- 0.88834 Table 6.4.2-3 5 800 -- 0.87591 Table 6.4.2-5 NCT Package Array 100 515 360 0.63941 Table 6.5.2-2 20 635 360 0.63022 Table 6.5.2-6 10 685 360 0.63621 Table 6.5.2-9 5 800 360 0.59731 Table 6.5.2-12 HAC Package Array 100 515 144 0.93502 Table 6.6.2-1 20 (CSI=0.7) 605 144 (N=72) 0.93645 Table 6.6.2-4 20 (CSI=1.0) 635 105 (N=52.5) 0.93765 Table 6.6.2-7 10 685 144 0.93860 Table 6.6.2-10 5 800 144 0.93672 Table 6.6.2-14 6-4

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.1.2.3 5-inch Pipe Table 6.1.2-3 provides a summary of the results of the limiting cases from the VP-55 with 5-inch pipe container criticality safety analysis. These cases correspond to the limits presented in Table 6.2.3-1. These limits were determined in the NCT package array evaluation and subcriticality was subsequently verified for the single package and HAC package array configurations.

Table 6.1.2-3. Summary of the VP-55 with 5-inch Pipe Container Evaluation 235 235 U Enrichment U Mass Array keff + 2 Reference (wt.%) (g) Size Single Package 100 695 -- 0.86526 20 1215 -- 0.83378 Table 6.4.3-2 10 1605 -- 0.78956 NCT Package Array 100 695 252 0.93824 20 1215 252 0.93784 Table 6.5.3-2 10 1605 360 0.91337 HAC Package Array 100 695 105 0.89434 20 1215 105 0.89207 Table 6.6.3-3 10 1605 144 0.86394 6-5

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.1.2.4 5-inch Pipe Hydrogen-Limited Contents Table 6.1.2-4 provides a summary of the results of the limiting cases from the VP-55 with 5-inch pipe hydrogen-limited contents evaluation. These cases correspond to the limits presented in Table 6.2.4-1. The unlimited contents were determined to be subcritical and below the USL for all package evaluations.

Table 6.1.2-4. Summary of the VP-55 with 5-inch Pipe Container Hydrogen-Limited Contents Evaluation 235 Number U Enrichment Array of 5-inch VFUA keff + 2 Reference (wt.%) Size Pipes Single Package 20 1 0.14 -- 0.76059 Table 6.4.4-1 10 2 0.16 -- 0.80980 NCT Package Array 20 1 0.916 360 0.77501 Table 6.5.4-1 10 2 0.916 360 0.76016 HAC Package Array 20 1 0.10 105 0.82559 Table 6.6.4-4 10 (UO2) 2 0.20 105 0.90608 Table 6.6.4-3 10 (U-Metal) 2 0.14 72 0.93710 Table 6.6.4-5 A

Note: VFU refers to the volume fraction of the uranium compound. Thus, for UO2 cases, VFU refers to the volume fraction of UO2.

6-6

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.1.2.5 1S / 2S UF6 Cylinder Configuration Table 6.1.2-5 provides a summary of the results of the limiting single package cases from the VP-55 with 1S and 2S UF6 cylinder criticality safety analysis. Table 6.1.2-6 provides a summary of the results of the limiting NCT package array cases from the VP-55 with 1S and 2S cylinders criticality safety analysis. Table 6.1.2-7 provides a summary of the results of the most limiting HAC package array cases from the VP-55 with 1S and 2S cylinders criticality safety analysis.

These cases correspond to the limits presented in Table 6.2.5-1.

Table 6.1.2-5. Single Package VP-55 1S/2S Cylinder Contents Evaluation Summary Uranium U-235 Case Content Mass per Configuration keff + 2 Enrichment Cylinder (g) 1S Cylinders HAC: 5-inch Pipe Three (3) 1S VP-55_5IP_1S_100_HAC_UO2F2_SINR_26.67_in 100 a 306 (full) Fill Height = 26.67 cm 0.82170 Cylinders Cylinder Spacing = 0.01 cm Seven (7) 1S HAC: Fissile Sphere VP-55_1S_020_HAC_UO2F2_SIN_2149_600_in 20 307 (full) 0.81423 Cylinders H/U-235 = 600 2S Cylinders VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_ One (1) 2S HAC: 5-inch Pipe 100 a 1497 (full) 0.79059 45.72_POS_2_in Cylinder Fill Height = 45.72 cm Two (2) 2S HAC: Fissile Sphere VP-55_2S_020_HAC_UO2F2_SIN_3004_550_in 20 1502 (full) 0.88226 Cylinders H/U-235 = 550 Note: 100-wt.% U enrichment requires each UF6 cylinder be placed in a separate 5-inch pipe.

a 235 Table 6.1.2-6. NCT Package Array VP-55 1S/2S Cylinder Contents Evaluation Summary U-235 Uranium Mass Case Content Configuration keff + 2 Enrichment per Cylinder (g) 1S Cylinders 1S Cylinder Shapes VP-55_1S_100_NCT_UO2F2_4x252_ Three (3) 1S Fill Height = 22.225 cm 100 306 (full) 0.60159 306_22.225_4.5_2.5_in Cylinders Cylinder Reflector = 4.5 cm Cylinder Spacing = 2.5 cm 1S Cylinder Shapes VP-55_1S_020_NCT_UO2F2_4x252_ Seven (7) 1S Fill Height = 22.225 cm 20 307 (full) 0.68991 307_22.225_3.5_2_in Cylinders Cylinder Reflector = 3.5 cm Cylinder Spacing = 2.0 cm 2S Cylinders 2S Cylinder Shapes VP-55_2S_100_NCT_UO2F2_4x252_ One (1) 2S 1250 100 Fill Height = 20.0025 cm 0.64567 1250_20.003_5.5_in Cylinder (partial fill)

Cylinder Reflector = 5.5 cm 2S Cylinder Shapes VP-55_2S_020_NCT_UO2F2_4x252_ Two (2) 2S Fill Height = 20.0025 cm 20 1502 (full) 0.67286 1502_20.003_4.5_0.5_in Cylinders Cylinder Reflector = 4.5 cm Cylinder Spacing = 0.5 cm 6-7

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.1.2-7. HAC Package Array VP-55 1S/2S Cylinder Contents Evaluation Summary U-235 Uranium Mass Case Content Configuration keff + 2 Enrichment per Cylinder (g) 1S Cylinders 5-inch Pipes Fill Height = 31.75 cm VP-55_5IP_1S_100_HAC_UO2F2_3x105_ Three (3) 1S Cylinder Reflector = 0.0 cm 306_31.75_0_0.01 100 a Cylinders 306 (full)

Cylinder Spacing = 0.01 cm 0.90124 Flooding: 0.0001 VF interspersed moderation Fissile Sphere VP-55_1S_020_HAC_UO2F2_3x105_ Seven (7) 1S H/U-235 = 650 2149_FLD1_1_650 20 Cylinders 307 (full)

Flooding: fully flooded inner 0.83438 cavity 2S Cylinders 5-inch Pipe Fill Height = 53.975 cm VP-55_5IP_2S_100_HAC_UO2F2_3x105_ One (1) 2S 1497_53.975_1_in 100 a Cylinder 1497 (full) Cylinder Reflector = 1.0 cm 0.86421 Flooding: 0.0001 VF all regions Fissile Sphere VP-55_2S_020_HAC_UO2F2_3x105_ Two (2) 2S H/U-235 = 700 3004_FLD1_0.1_700_in 20 Cylinders 1502 (full)

Flooding: 0.1 VF inner 0.91529 cavity Note: a 100-wt.% 235U enrichment requires each UF6 cylinder be placed in a separate 5-inch pipe.

6-8

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.1.2.6 High-Capacity Basket with Hydrogen-Limited Contents Table 6.1.2-8 provides a summary of the results of the limiting cases from the VP-55 with High-Capacity Basket hydrogen-limited contents evaluation. These cases correspond to the limits presented in Table 6.2.6-1. As UC bounds U3O8, only one single package evaluation was done with UC as the bounding fissile material. One NCT array evaluation was done that combined the bounding fissile material of UC (CSI=1.4) with the U3O8 (CSI=0.7) bounding array size of 5N=360.

Thus, the single NCT array evaluation bounds both the UC (CSI=1.4) and U3O8 (CSI=0.7) contents. The contents were determined to be subcritical and below the USL for all package evaluations.

Table 6.1.2-8. Summary of the VP-55 with High-Capacity Basket Hydrogen-Limited Contents Evaluation 235 U Enrichment Array VFUA keff + 2 Reference (wt.%) Size Single Package 20 (UC) 0.14 -- 0.71524 Table 6.4.6-1 NCT Package Array 20 (UC) 0.916 360 0.88935 Table 6.5.6-4 HAC Package Array 20 (UC) 0.14 72 0.92800 Table 6.6.6-10 20 (U3O8) 0.18 144 0.93882 Table 6.6.6-10 A

Note: VFU refers to the volume fraction of the uranium compound. Thus, for UC cases, VFU refers to the volume fraction of UC.

6-9

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.1.2.7 Determination of Upper Subcritical Limits All USLs used throughout Section 6 are calculated and summarized here. Table 6.1.2-9 summarizes the USLs as determined using the SCALE 6.1.3 bias and USL evaluations of Section 6.8. For all USL equations except the HCB, the trending parameter is H/235U. For the HCB, the USL trending parameter is EALF. All USLs have an administrative margin (km) of 0.05.

Table 6.1.2-9. Upper Subcritical Limits for All Versa-Pac Configurations Enrichment Trending Limiting USL Equation USL (wt.%) Parameter Parameter Standard Configuration

= 0.9380 + (4.6142E-06)*X (X < 449.05) 100 H/X 507 0.9400

= 0.9400 (X 449.05)

= 0.9430 + (-1.1708E-06)*X (X > 1259.8) 20 H/X 671 0.9416

= 0.9416 (X 1259.8)

= 0.9442 + (-2.0831E-06)*X (X > 1295.4) 10 H/X 730 0.9415

= 0.9415 (X 1295.4)

= 0.9480 + (-6.7842E-06)*X (X > 881.42) 5 H/X 597 0.9420

= 0.9420 (X 881.42)

= 0.9476 + (-8.9099E-06)*X (X > 545.43) 1.25 H/X 585 0.9423

= 0.9427 (X 545.43)

Standard Configuration with Hydrogen-Limited Contents

= 0.9380 + (4.6142E-06)*X (X < 457.11) 100 H/X 651 0.9400

= 0.9400 (X 457.11)

= 0.9430 + (-1.1708E-06)*X (X > 1259.8) 20 (CSI=0.7) H/X 703 0.9416

= 0.9416 (X 1259.8)

= 0.9430 + (-1.1708E-06)*X (X > 1259.8) 20 (CSI=1.0) H/X 702 0.9416

= 0.9416 (X 1259.8)

= 0.9442 + (-2.0831E-06)*X (X > 1295.4) 10 H/X 643 0.9415

= 0.9415 (X 1295.4)

= 0.9480 + (-6.7842E-06)*X (X > 881.42) 5 H/X 623 0.9420

= 0.9420 (X 881.42) 5-inch Pipe

= 0.9380 + (4.6142E-06)*X (X < 449.05) 100 H/X 311 0.9394

= 0.9400 (X 449.05)

= 0.9430 + (-1.1708E-06)*X (X > 1259.8) 20 H/X 179.7 0.9416

= 0.9416 (X 1259.8)

= 0.9385 + (7.8443E-06)*X (X < 241.40) 10 H/X 125.3 0.9394

= 0.9404 (X 241.40) 5-inch Pipe with Hydrogen-Limited Contents

= 0.9430 + (-1.1708E-06)*X (X > 1259.8) 20 H/X 38 A 0.9416

= 0.9416 (X 1259.8)

= 0.9385 + (7.8443E-06)*X (X < 241.40) 10 H/X 76.4 0.9391

= 0.9404 (X 241.40) 6-10

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Enrichment Trending Limiting USL Equation USL (wt.%) Parameter Parameter 1S/2S UF6 Cylinders

= 0.9380 + (4.6142E-06)*X (X < 449.05) 100, 1S H/X 343.6 0.9395

= 0.9400 (X 449.05)

= 0.9380 + (4.6142E-06)*X (X < 449.05) 100, 2S H/X 115.9 0.9385

= 0.9400 (X 449.05)

= 0.9430 + (-1.1708E-06)*X (X > 1259.8) 20, 1S H/X 650 0.9416

= 0.9416 (X 1259.8)

= 0.9430 + (-1.1708E-06)*X (X > 1259.8) 20, 2S H/X 700 0.9416

= 0.9416 (X 1259.8)

Air Transport

= 0.9380 + (4.6142E-06)*X (X < 449.05) 100 H/X 525 0.9400

= 0.9400 (X 449.05)

= 0.9430 + (-1.1708E-06)*X (X > 1259.8) 20 H/X 550 0.9416

= 0.9416 (X 1259.8)

= 0.9442 + (-2.0831E-06)*X (X > 1295.4) 10 H/X 550 0.9415

= 0.9415 (X 1295.4)

= 0.9480 + (-6.7842E-06)*X (X > 881.42) 5 H/X 525 0.9420

= 0.9420 (X 881.42)

High-Capacity Basket with Hydrogen-Limited Contents 20 (CSI=1.4) = 0.9412 + (-6.7656E-03)*X (X > 0.19317) EALF 0.7560 eV 0.9360 20 (CSI=0.7) = 0.9399 (X 0.19317) EALF 0.3054 eV 0.9391 Note: A H/X value outside the AOA deemed acceptable for two reasons. First, the USL is constant at lower H/X values indicating a positive bias, so further decreasing the USL should not result in a decrease in the USL. Second, the maximum value of keff for this content at 20 wt.% is ~0.83, so there is significant additional margin.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.1.3 Criticality Safety Index (CSI)

The Criticality Safety Index (CSI) for the Versa-Pac is calculated as follows. The number N is defined in 10 CFR 71.59 [2] as that number such that five times N undamaged packages (i.e., NCT) with no moderation between the packages, and two times N damaged packages (i.e., HAC) with optimum interspersed moderation would be subcritical. Further, N cannot be less than 0.5. The array sizes for all contents are presented in Table 6.1.3-1. Using the array sizes, a minimum N, and its corresponding CSI, is calculated for all contents. Note that in some cases, the NCT array is oversized, but in these instances N and the CSI are based on the smaller HAC array size.

Table 6.1.3-1. Criticality Safety Indices for All Contents U-235 Enrichment NCT Array Size HAC Array Size Contents N CSI (wt.%) (5N) (2N)

Standard All enrichments 252 105 50.4 1.0 Hydrogen- 100, 20 (605 gU-235),

360 144 72 0.7 Limited 10, 5 Contents 20 (635 gU-235) 360 105 52.5 1.0 100, 20 252 105 50.4 1.0 5-inch Pipe 10 360 144 72 0.7 5-inch Pipe 20, 10 (UO2) 360 105 52.5 1.0 Hydrogen-Limited 10 (U Metal) 360 72 36 1.4 1S/2S All enrichments 252 105 50.4 1.0 HCB Hydrogen- 20 (UC) 360 72 36 1.4 Limited 20 (U3O8) 360 144 72 0.7 6-12

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.2 Fissile Material Contents All restrictions on the standard configuration are applicable to all other configurations unless otherwise noted.

No contents are credited as neutron absorbers for the purposes of criticality safety. However, neutron absorbers/poisons are allowed as contents with no alteration to any of the subsequent fissile limits. Neutron absorbers/poisons include, but are not limited to, boron, erbium, gadolinium, and hafnium.

6.2.1 Standard Configuration All hydrogenous packing materials must have a hydrogen density no greater than 0.141 g/cm3.

Metallic packing materials consisting of aluminum, stainless steel, or carbon steel are allowed provided the weight limits of the package are not exceeded. All packing materials must have an auto-ignition temperature greater than 600 °F (316 °C). No mixing of radioactive content forms is allowed.

Materials that may be shipped in the Versa-Pac standard configuration include uranium oxides (UyOx), uranium metal (U-metal), uranyl nitrate crystals (UNX), and other uranium compounds (e.g., Uranyl Fluorides and Uranyl Carbonates) with U-235 mass limited by enrichment, as shown in Table 6.2.1-1. The uranium compounds may also contain carbon or graphite (e.g., UC, U2C3, and UC2). UNX may be in the form of uranyl nitrate hexahydrate, trihydrate or dihydrate, and may contain any amount of moisture. All material shall be in solid form with no freestanding liquids.

The density of the contents is not limited. The contents may be in homogeneous (e.g. powders, solutions, etc.) or heterogeneous form (e.g. pellets, millings, etc.). As the VP-55 is a Type AF packaging transporting normal form material, all radionuclides A2 limits as stated in 10 CFR 71 [2]

are applied to the package. All radioactive contents must have an auto-ignition temperature and melting point greater than 600 °F (316 °C). The contents may not exceed the uranium limits shown in Table 6.2.1-1 in any non-pyrophoric form.

The package supports packaging applications containing both carbon (graphite) and hydrogen-based materials. Non-fissile chemical impurities do not increase the multiplication factor of the system; therefore, they may be present in any quantity. The contents may be packed in hydrogenous or non-hydrogenous containers within the payload vessel. Metallic packing materials are allowed provided the weight limits of the package are not exceeded.

Table 6.2.1-1. Uranium Mass Limits for Standard Configuration U-235 Mass U-235 Enrichment (g)

(wt.%) Ground/Vessel Air 100 360 360 20 445 445 10 505 505 5 610 610 1.25 1650 --

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.2.2 Hydrogen-Limited Standard Contents Including TRISO Fuels If the fissile contents are to use the hydrogen-limited contents fissile mass limits in Table 6.2.2-1, the following conditions apply:

• All hydrogenous packing materials must have a mass 1 lb (454 g) and a hydrogen density 0.141 g/cm3.

• Uranium compounds containing any hydrogen (e.g., hydrates or hydrides) are not authorized.

• Uranium compounds containing carbon, including uranium carbide or mixed with carbon or graphite, are authorized for shipment. Graphite not chemically or mechanically bound to the uranium contents, not in the fuel-free zone of TRISO compacts, or not otherwise mixed with the uranium (i.e., loose graphite) is not allowed.

TRISO fuels and compacts are contents composed of uranium kernels encased within layers of graphite and SiC to form TRISO particles. The uranium kernels may be in the form of uranium oxides, carbides, and/or nitrides. Uranium kernels and TRISO particles are of unrestricted size, density, and uranium content per kernel/particle and may be loose or mixed in a graphite matrix and pressed into various fuel forms/compacts (e.g., annular cylinders, planks, right circular cylinders, spheres, etc.). The payload is limited by enrichment, as shown in Table 6.2.2-1, with two U-235 mass limits for 20-wt.% enrichment based on CSI.

Table 6.2.2-1. Uranium Mass Limits for 1 lb. Hydrogen-Limited Contents Enrichment Mass U-235 U-235 (g)

(wt.%) CSI = 0.7 CSI = 1.0 Air 100 515 -- 395 20 605 635 495 10 685 -- 590 5 800 -- 790 6-14

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.2.3 5-inch Pipe The VP-55 5-inch Pipe configuration is derivative of the standard configuration with the exception that criticality control relies on the 5-inch pipe. However, control relies only on the 5-inch pipes geometry and not its positioning inside the package. Hence, no credit is taken for the position of the 5-inch pipe inside the inner container. The contents for the 5-inch pipe container are limited by mass according to U-235 enrichment, as shown in Table 6.2.3-1. The following restrictions apply:

• All hydrogenous packing materials inside the 5-inch pipe are unlimited but must have a maximum hydrogen density 0.141 g/cm3.

• All hydrogenous packing materials inside the VP-55 inner container but outside of the 5-inch pipe are unlimited but must not have a hydrogen-density greater than that of water, 0.1117 g/cm3.

• All radioactive contents must be in a 5-inch pipe.

• Unlimited contents are limited only by the volume of radioactive material that can fit in a 5-inch pipe.

Table 6.2.3-1. Uranium Mass Limits - VP-55 with 5-inch Pipe Configuration U-235 Maximum 5- Mass U-235 per VP-55 Enrichment inch Pipes per (g)

(wt.%) Package Ground/Vessel Air 100 1 695 395 20 1 1215 495 10 1 Unlimited 590 6-15

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.2.4 5-inch Pipe Hydrogen-Limited Contents The VP-55 5-inch Pipe with hydrogen-limited contents is derivative of the 5-inch pipe contents with the exception that criticality control additionally relies on limiting the quantity of hydrogen packing materials in one or two 5-inch pipes. Control relies only on the 5-inch pipes geometry, not its positioning inside the package. Hence, no credit is taken for the position of the 5-inch pipe inside the inner container in this analysis. The 5-inch pipe hydrogen-limited contents are limited by number of 5-inch pipes per VP-55 only, as shown in Table 6.2.4-1. If used for transport by air, the Air transport U-235 mass limits listed in Table 6.2.4-1 apply.

• All hydrogenous packing materials must be in the 5-inch pipe and have a total mass 1.25 lb (567 g) per pipe, with a hydrogen density 0.141 g/cm3.

• All radioactive contents must be in the 5-inch pipe(s).

• Fissile contents are limited only by the volume of the 5-inch pipe (s).

• Uranium compounds containing any hydrogen (e.g. hydrates or hydrides) are not authorized.

• Uranium compounds containing carbon, including uranium carbide, or mixed with carbon or graphite, are authorized for shipment. Graphite not chemically or mechanically bound to the uranium contents, not in the fuel-free zone of TRISO compacts, or not otherwise mixed with the uranium (i.e., loose graphite) is not allowed.

• For uranium oxides enriched up to 10-wt.% 235U, unlimited uranium contents are allowed in two 5-inch pipes per VP-55 with CSI=1.0. For all other permissible uranium forms enriched up to 10-wt.% 235U, unlimited uranium contents are allowed in two 5-inch pipes per VP-55 with CSI=1.4.

Table 6.2.4-1. Uranium Mass Limits - VP-55 with 5-inch Pipe Hydrogen-Limited Contents U-235 Maximum 5- Mass U-235 per VP-55 Enrichment inch Pipes Per CSI (g)

(wt.%) VP-55 Ground/Vessel Air 20 1 1.0 Unlimited 495 10 (UO2) 2 1.0 Unlimited 590 10 2 1.4 Unlimited 590 6-16

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.2.5 1S/2S Cylinder Configuration If the contents are 1S or 2S cylinders, the contents may not exceed the limits in Table 6.2.5-1.

The fissile material of the 1S/2S cylinder configuration is in the form of uranium hexafluoride (UF6).

The cylinders must conform to the standards presented in the version of ANSI N14.1 effective at the time of manufacturing [1]. No packing materials with a hydrogen density greater than that of light water (0.1119 g/cm3) are allowed in the VP-55 1S/2S cylinder configuration.

Criticality control relies only on these cylinders geometry and not their positioning inside the package. The payload for the 1S/2S cylinders is limited by mass per ANSI N14.1, as shown in Table 6.2.5-1. Air transport U-235 mass limits in Table 6.2.5-1 are the lesser of the 1S/2S cylinder limits and the air transport limits determined in Section 6.7. Note that each shipment of this content type must only contain either 1S cylinders or 2S cylinders. Quantities of cylinders greater than the limits stated in Table 6.2.5-1, or combinations of 1S and 2S cylinders in a single package (e.g.

one 1S cylinder and one 2S cylinder), are permissible if the total U-235 quantity meets the fissile limits established in Table 6.2.1-1.

Table 6.2.5-1. Maximum Quantity of 1S/2S Cylinders and Uranium Limits for the VP-55 Enrichment Cylinders Maximum Total Mass Total Mass Air U-235 Content U-235 in 5-inch Cylinders UF6 per VP-55 U-235 per VP-55 Mass Limit (wt.%) Pipe? per VP-55 (lb/g) (g) (g) 1S 100 Yes 3 3.0 / 1,360.8 918 395 Cylinder 20 No 7 7.0 / 3,175.2 429.8 429.8 2S 100 Yes 1 4.9 / 2,222.6 1,497 395 Cylinder 20 No 2 9.8 / 4,445.2 600.8 495 6-17

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.2.6 High-Capacity Basket with Hydrogen-Limited Contents The VP-55 High-Capacity Basket (HCB) with hydrogen-limited contents configuration is derivative of the 5-inch pipe with hydrogen-limited contents with the exception that criticality control additionally relies upon the HCB for HAC. The HCB allows for two (2) 5-inch pipes to be loaded with unlimited uranium compound contents enriched to no more than 20-wt.% 235U. Criticality control relies on the HCBs moderator pipes and separator plate, its positioning inside the package, and the 5-inch pipes geometry. The HCB hydrogen-limited contents are limited by the volume of two 5-inch pipes per VP-55, as shown in Table 6.2.6-1. If used for transport by air, the Air transport 235U mass limits listed in Table 6.2.6-1 apply. The following restrictions apply:

• All hydrogenous packing materials must be in the 5-inch pipes and have a total mass 1.25 lb (567 g) per pipe, with a hydrogen density 0.141 g/cm3.

o Uranium compounds containing any hydrogen (e.g., hydrates or hydrides) are not authorized.

• All radioactive contents must be in the 5-inch pipe(s).

• Fissile contents are limited only by the inner volume of the 5-inch pipe(s).

• Graphite not chemically or mechanically bound to the uranium contents, not in the fuel-free zone of TRISO compacts, or not otherwise mixed with the uranium (i.e., loose graphite) is not allowed.

• For Uranium Carbide (UC) enriched up to 20-wt.% 235U, unlimited UC contents are allowed in two 5-inch pipes with the HCB with CSI=1.4. Per Section 6.6.6.2, UC has been determined to bound uranium carbides, fluorides, nitrides, and oxides. These uranium compounds may be loaded per the UC limits in Table 6.2.6-1.

o Although Uranium Fluorides are an authorized content in the HCB configuration, UF6 is not an authorized content.

• For Uranium Oxide (U3O8) enriched up to 20-wt.% 235U, unlimited U3O8 contents are allowed in two 5-inch pipes in the HCB with CSI=0.7. Per Section 6.6.6.3, U3O8 has been determined to bound UF4 and UO3. These uranium compounds may be loaded per the U3O8 limits in Table 6.2.6-1.

Table 6.2.6-1. Uranium Mass Limits - VP-55 with HCB Hydrogen-Limited Contents U-235 Maximum 5- Mass U-235 per VP-55 Enrichment inch Pipes Per CSI (g)

(wt.%) VP-55 Ground/Vessel Air 20 (UC) 2 1.4 Unlimited 495 20 (U3O8) 2 0.7 Unlimited 495 6-18

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3 General Considerations 6.3.1 Model Configuration The 55-gallon and 110-gallon Versa-Pac Shipping Containers (VP-55 & VP-110) consist of a cylindrical carbon steel shell representing the inner container, an inner/outer steel liner, and an outer carbon steel shell surrounded by the drum skin. The steel payload vessel, flange, and blind flange are modeled as carbon steel with reduced minimum dimensions. The drum, inner and outer liners, and upper and lower drum plates are also modeled as carbon steel with reduced minimum dimensions. The four vertical members (square tubing), reinforcing angles, and bottom plate ring constructed from carbon steel have also been conservatively neglected resulting in modeling less than 50% of the packagings total carbon steel. All insulation products are conservatively neglected, allowing for greater water moderation in those regions.

The criticality analysis model is constructed based on the VP-55 package dimensions, due to the potential for higher package and fissile mass densities, coupled with the conservative application of actual damage sustained during testing of both the VP-55 and VP-110, as listed in Table 2-6.

Therefore, the NCT and HAC configurations analyzed bound both the VP-55 and VP-110 packages.

The nominal dimensions of the VP-55 packaging are an outer diameter of 23.0625 in.

(58.5788 cm) by a height of 34.75 in. (88.27 cm). For the criticality safety model, the drum stiffeners and bolt ring are both omitted. Neglecting these components reduces the outer diameter to 22.50 in. (57.15 cm). Damage that resulted from NCT drop tests (Section 2.6) was minimal. The only deformation modeled in the VP-55 NCT model is a reduction in the outer diameter of the package of 0.125 inches (0.3176 cm). All other dimensions are modeled nominally and at reduced tolerances.

The worst-case dimensional changes from the HAC tests (Section 2.7) are: a 0.125 in. (0.318 cm) increase in the inner containment diameter, a 1.188 in. (3.018 cm) decrease in the outer drum diameter, and a 0.25 in. (0.635 cm) decrease in the outer drum height (including lid). Note that the measured dimensions do not include the outer drum lid. Also, the outer drum diameter reduction only occurs on one side of the drum mostly due to compression of the area between drum stiffeners at the impact location of the test plate. The HAC model dimensional changes are as follows:

• The VP-55 drum outer diameter is reduced 1.313 in. (3.335 cm) to 21.187 in. (53.815 cm),

which bounds the 0.313 in. (0.795 cm) decrease resulting from the tests.

• The VP-55 drum height is reduced by 1.10 in. (2.79 cm) to 33.625 in. (85.408 cm), which bounds the maximum reduced dimension resulting from the tests of 0.25 in. (0.64 cm).

• The containment inner diameter is modeled at a nominal 15.0 in. (38.1 cm) and increased by 0.125 in. (0.318 cm) to 15.125 in. (38.418 cm). These correspond to a 19.05 cm radius and 19.2088 cm radius, respectively.

• The containment inner height is modeled at 27.187 in. (69.055 cm).

Table 6.3.1-1 and Table 6.3.1-2 provide comparisons of the axial and radial nominal packaging dimensions, respectively, with the NCT and HAC model dimensions. The NCT and HAC models are shown in Figure 6.3.1-1 and Figure 6.3.1-2, respectively.

6-19

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.3.1-1. VP-55 Radial Dimensions Nominal NCT HAC Dimension in. cm in. cm in. cm Inner container inner 15.0 38.1 15.0 38.1 15.125 38.4176 diameter Inner container wall 0.1345 0.3416 0.1211 0.3076 0.1211 0.3075 thickness (PA)

Insulation thickness (IA) 2.0 5.08 2.5 6.35 2.5 6.35 Inner liner wall 0.0598 0.1519 0.0533 0.1354 0.0533 0.1354 thickness (SA)

Outer vertical and horizontal tubing and 1.5 3.81 0.9065 2.3025 0.2503 0.6357 angles Outer liner wall 0.0598 0.1519 0.0533 0.1354 0.0533 0.1353 thickness (FC)

Drum wall thickness 0.0354 0.09 0.0533 0.1354 0.0533 0.1354 (DA)

Bottom chime 0.3043 0.7729 0.0 0.0 0.0 0.0 Drum outer radius 11.5938 29.4481 11.1875 28.4163 10.5937 26.9081 Table 6.3.1-2. VP-55 Axial Dimensions Nominal NCT HAC Dimension in. cm in. cm in. cm Drum bottom thickness 0.0354 0.09 0.0533 0.1354 0.0533 0.1354 (DA)

Reinforcement plate 0.25 0.635 0.2361 0.5996 0.24 0.6096 (PE)

Bottom insulation layer 2.75 6.985 2.75 6.985 2.5 6.35 thickness (IB)

Inner container bottom 0.1345 0.3416 0.1211 0.3076 0.1211 0.3076 wall thickness (PB)

Inner container inner 26.125 66.3575 27.0625 68.7388 27.1875 69.0562 height Inner container closure 0.5 1.27 0.49 1.2446 0.49 1.2446 lid wall thickness (PD)

Lid-to-plug gap 0.625 1.5875 0.9065 2.3025 0.4265 1.0833 Inner plug liner (SC) 0.0598 0.1519 0.0533 0.1354 0.0533 0.1354 Top insulation layer 2.3125 5.8738 2.5 6.35 2.5 6.35 thickness (IC)

Drum lid (DL) 0.0472 0.12 0.0533 0.1354 0.0533 0.1354 Drum outer height 34.75 A 88.265 34.2261 86.9343 33.6250 85.4075 Note: A This is the nominal VP-55 height per Section 1.4.1. Note the dimensions in this column sum to 32.8395 in. The bottom chime, lower ceramic paper region, and upper bolt ring constitute this difference in dimensions, 1.9105 in. (4.8527 cm), as the dimensions for these components are not listed in VP-55-LD.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.3.1-1. VP-55 NCT Model Top (left) and Side (right) Views Figure 6.3.1-2. VP-55 HAC Model Top (left) and Side (right) Views 6-21

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.1.1 5-inch Pipe Container The 5-inch pipe container is designed to the prior DOT specification of the 2R container. The 5-inch pipe is modeled as a right circular cylinder made of carbon steel with an inner diameter of 5.047 in. (12.819 cm) and a wall thickness of 0.258 in. (0.655 cm). The inner height is modeled as 21.25 in. (53.98 cm) and the top and bottom caps were modeled as 0.25 in (0.64 cm) thick for an outer height of 21.75 in. (55.25 cm). The top cap was reduced to a simple disc, as opposed to the dome cap shown in the 5 Pipe Container Licensing Drawing (Section 1.4.6). Modeling the cap as a simple disc is conservative because less material is modeled that would otherwise moderate or reflect neutrons and the pipe becomes slightly more voluminous with the disc simplification, allowing for more fissile material. The model in this analysis assumes only three out of eight of the pipe threads are engaged by the cap. Modeling the pipe with only three pipe threads engaged is conservative because it lengthens the pipe container, allowing for a bounding inner volume.

6.3.1.2 1S/2S UF6 Cylinders Figure 6.3.1-3 shows cross-section views of a 1S cylinder and a 2S cylinder from ANSI N14.1 [1].

In the evaluation of 1S/2S UF6 cylinders, the analysis assumes the cylinders survive NCT. The cylinders are conservatively modeled as right circular cylinders with the maximum pressure vessel outer diameter and the maximum cylinder assembly height, as shown in Figure 6.3.1-3. None of the materials of construction of the cylinders are modeled, which is bounding. For HAC, it is assumed that the cylinders do not survive and that the contents escape their cylinders (but not the inner container of the Versa-Pac or the 5-inch pipe, when applicable). Thus, it is assumed the fissile contents can take any shape for HAC.

Figure 6.3.1-3. ANSI N14.1 1S Cylinder (Top) and 2S Cylinder (Bottom) 6-22

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.1.2.1 20-wt.% U-235 Enrichment Under NCT, the 1S cylinders are modeled as a cylinder group, as shown in Figure 6.3.1-4. Under HAC, the cylinders are not assumed to survive, therefore, the fissile material, representing an equivalent number of 1S cylinders, is modeled as an optimally moderated, homogeneous water solution sphere inside the Versa-Pac inner cavity.

Under NCT, the 2S cylinders are modeled as a cylinder group, as shown in Figure 6.3.1-5. Under HAC, the cylinders are not assumed to survive, therefore, the fissile material, representing an equivalent number of 2S cylinders, is modeled as an optimally moderated, homogeneous water solution sphere inside the Versa-Pac inner cavity.

6.3.1.2.2 100-wt.% U-235 Enrichment Under NCT, the 1S cylinders are modeled as a cylinder group, as shown in Figure 6.3.1-4. Under HAC, the cylinders are not assumed to survive, therefore, the fissile material representing each 1S cylinder is modeled inside separate 5-inch pipes, as shown in Figure 6.3.1-6.

Under NCT, the 2S cylinders are modeled as a cylinder group, as shown in Figure 6.3.1-5. Under HAC, the cylinder is not assumed to survive, therefore, the fissile material representing the 2S cylinder is modeled inside a 5-inch pipe.

Figure 6.3.1-4. Top, Side Views of the 1S Cylinder Group Figure 6.3.1-5. Top, Side Views of the 2S Cylinder Group 6-23

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.3.1-6. Top, Side Views of Three 1S Cylinders, Each in a 5-inch Pipe - HAC 100-wt.% U-235 6-24

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.1.3 High-Capacity Basket The High-Capacity Basket (HCB) consists of an aluminum structure within which sit two neutron moderator pipes that each house a single 5-inch pipe and a center separator plate between them with insulation filling the spaces between. The HCB is modeled in the criticality safety analysis as only its two moderator pipes and one separator plate. The remaining structure and material of the HCB is conservatively neglected, allowing for more flooding volume under HAC. Despite neglecting the structural materials of the HCB, the HCBs structural integrity and positioning is credited as surviving all conditions of transport. In addition, the HCBs thermal integrity is credited as surviving all conditions of transport, i.e., no loss of material to thermal degradation. Thus, the HCB model is identical under NCT and HAC. The relevant dimensions of the HCB are, the inner and outer diameters of the CPVC pipes, the width and thickness of the CPVC plate, and the overall heights of each component, as listed on the HCB licensing drawing provided in Section 1.4.9. The components are all modeled as shown in Figure 6.3.1-7, so the center to center spacing of the pipes is based on the outer diameters of the pipes and thickness of the plate.

In addition, the space filled by the Versa-Pacs inner container Containment Plug (IG) is credited.

This region is still analyzed as void, floodable space, but this region limits the axial movement of the 5-inch pipes in the HCB. Part IG is affixed to the bottom surface of the containment lid and has a height of 3 in.

Figure 6.3.1-7. Top (Left) and Side (Right) Views of HCB Model 6-25

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.2 Material Properties All materials are modeled using the built-in materials provided with SCALE 6.1.3. Unless otherwise noted, this means all elements are modeled at their natural isotopic abundances and proper thermal scattering kernels are included. All materials are modeled at 300 K.

6.3.2.1 Uranium Metal All uranium metal is modeled as the built-in SCALE material u. This built-in material is modeled at its theoretical density, 19.05 g/cm3. All uranium is modeled as U-235 and U-238 with no credit taken for U-234 or U-236, all of which is conservatively replaced by U-238. This material is summarized in Table 6.3.2-2.

6.3.2.2 Uranyl Fluoride (UO2F2)

Although 1S and 2S cylinders carry UF6, all UF6 in the 1S/2S analysis is modeled as UO2F2.

UO2F2 is a uranium compound denser than UF6 that is created when UF6 is exposed to water, such as with water in-leakage. Therefore, it is assumed that all UF6 is replaced by a homogeneous solution of uranyl fluoride (UO2F2) and light water. When UF6 mixes with water, hydrofluoric acid (HF) is also created. The HF is conservatively ignored in this analysis because H2O is approximately twice as hydrogen dense as HF (0.11 g/cm3 vs. 0.05 g/cm3), and any HF modeled would displace the denser H2O, resulting in decreased moderation and a reduction in keff.

The UO2F2 is modeled with the isotopes U-235 and U-238, the ratio of U-235 to U-238 is a function of enrichment, with one uranium atom, two oxygen atoms, and two fluorine atoms per molecule.

The U-234 and U-236 are conservatively ignored and replaced with U-238. The UO2F2 is modeled as the built-in SCALE material uo2f2, which is modeled at its theoretical density, 6.37 g/cm3.

This material is summarized in Table 6.3.2-1. In all instances, this compound is modeled as a homogeneous solution with light water.

6.3.2.3 Uranium Hexafluoride (UF6)

UF6 is modeled in a sensitivity study to determine the effect of this compound on reactivity. The UF6 is modeled with only the isotopes U-235 and U-238, the ratio of which is a function of enrichment, with the ratio of one atom of uranium to six atoms of fluorine, as represented with the SCALE built-in material uf6. U-234 and U-236 are conservatively ignored and replaced with U-238. The material is modeled at its theoretical density, 4.68 g/cm3. This material is summarized in Table 6.3.2-1. In all instances, this compound is modeled as a homogeneous solution with light water.

6.3.2.4 Thorium All thorium modeled in this analysis is modeled as natural, elemental thorium, which solely consists of thorium-232 [3]. This is represented by the built-in SCALE material th. The natural thorium theoretical density provided in the SCALE input libraries, 11.7 g/cm3, is used to bound all compounds and forms of natural thorium. This material is summarized in Table 6.3.2-2 6.3.2.5 High-Density Polyethylene All polyethylene is modeled as high-density polyethylene (HDPE) with a density of 0.98 g/cm3.

With a corresponding hydrogen density of 0.141 g/cm3, HDPE bounds all hydrogen-containing 6-26

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 materials with a lesser hydrogen density. HDPE is represented by the built-in SCALE material polyethylene, with the chemical formula of CH2. All hydrogen is modeled as H-1 and the carbon is elemental carbon (only elemental carbon is included in the ENDF/B-VII.0 neutron cross-section library). Polyethylene includes the hydrogen-in-polyethylene S(,) thermal kernel. This material is summarized in Table 6.3.2-1.

6.3.2.6 Light Water All water is modeled as the built-in SCALE Standard Composition Library compound h2o. This material represents light water and consists of only H-1 and O-16. This material also includes the hydrogen-in-water S(,) thermal kernel. The density is modeled as the materials default density, 0.9982 g/cm3. This material is summarized in Table 6.3.2-1.

The light water of this analysis is the bounding packing material allowed in the VP-55 1S/2S UF6 Cylinder contents configuration. No materials with a hydrogen density greater than that of full-density water (0.1119 g/cm3) are allowed in the Versa-Pac with 1S or 2S cylinders as the content.

6.3.2.7 Carbon Steel All packaging steel of the Versa-Pac is modeled as the SCALE Standard Composition Library alloy carbonsteel. This material consists of 99-wt.% naturally occurring Fe and 1-wt.% C, with a density of 7.8212 g/cm3. This material is summarized in Table 6.3.2-2.

6.3.2.8 Stainless Steel For the inner cavity packing materials study of Section 6.4.1, all metallic packing materials are represented by stainless steel due to its high density. All stainless steel is modeled as the SCALE Standard Composition Library material ss304s. This material has a modeled density of 7.94 g/cm3 and its composition is summarized in Table 6.3.2-2.

6.3.2.9 Graphite The graphite analyzed in these evaluations is modeled as the built-in SCALE material graphite.

It is modeled at its theoretical density of 2.3 g/cm3. This material is summarized in Table 6.3.2-1.

6.3.2.10 Uranium Compounds for High-Capacity Basket Configuration All uranium compounds modeled for the HCB analysis are listed in Table 6.3.2-3. Most compounds are built-in SCALE materials [4], with the exception of Uranium Trifluoride (UF3),

which is referenced from an external source [5].

6.3.2.11 Moderator Pipe and Separator Plate Compounds The HCB features two CPVC moderator pipes and a CPVC separator plate. CPVC is a complex polymer that is a combination of resin and additives, which improve the compounds processability and increase its structural and thermal performance. Of all additives, only the pigments result in an increased keff over pure CPVC. Of the pigments, Carbon Black is bounding. Therefore, the maximum permissible pigment additive is modeled as Carbon Black in the CPVC components.

Sections 6.5.6.1 and 6.6.6.1 determined that the bounding CPVC porperties model the maximum allowable Chlorine and the minimum allowable material density. The two CPVC compositions are summarized in Table 6.3.2-4, based on the specification requirements for the CPVC components listed in Table 1-9.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.3.2-1. Summary of Compound Material Compositions Material Density Atoms per Isotope/Element (SCALE Material) (g/cm3) Molecule U 1 Uranyl Fluoride 6.37 O-16 2 (uo2f2)

F-19 2 Uranium U 1 Hexafluoride 4.68 (uf6) F-19 6 Polyethylene H-1 2 0.98 (polyethylene) C 1 Light Water H-1 2 0.9986 (h2o) O-16 1 Graphite Carbon 2.30 C 1 (graphite)

Reference:

[4] All materials, Table M8.2.4, Pages M8.2.72-M8.2.74.

Table 6.3.2-2. Summary of Elemental/Mixture Material Compositions Material Density Constituent Weight Percent (SCALE Material) (g/cm3)

Based on U-235 Uranium Metal enrichment 19.05 (u) Based on U-238 enrichment Thorium 11.70 Th-232 100.0 (th)

Carbon Steel Fe a 99.0 7.8212 (carbonsteel) Cb 1.0 Cb 0.08 Si a 1.0 31 P 0.045 Stainless Steel 304 7.94 Cr a 19.0 (ss304s) 55 Mn 2.0 Fe a 68.375 a

Ni 9.5

Reference:

[4] Uranium and Thorium, Table M8.2.2, Page M8.2.70.

[4] Carbon steel, Table M8.2.5, Page M8.2.75.

a Note: SCALE models the natural isotopic composition of this element.

b Carbon is modeled as elemental carbon in the ENDF/B-VII.0 cross-section library.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.3.2-3. Summary of Bounding Uranium Compounds for HCB Configuration Uranium Theoretical Bounding Uranium Chemical Compound Density Compound Formula Class (g/cm3)

Carbides Uranium Carbide UC 13.63 Fluorides Uranium Trifluoride UF3 8.9 Nitrides Uranium Mononitride UN 14.31 Oxides Uranium Dioxide UO2 10.96 Table 6.3.2-4. HCB CPVC Properties Separator Moderator CPVC Property Plate Pipe Carbon a (wt.%) 34.18 32.60 Hydrogen b (wt.%) 3.12 2.80 a

Chlorine (wt.%) 62.70 64.60 Density (g/cm3) 1.45 1.49 Note: a Modeled at natural isotopic abundances per SCALE material library.

b Modeled as hydrogen-in-polyethylene with corresponding S(,) thermal kernel 6-29

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.3 Computer Codes and Cross Section Libraries SCALE 6.1.3 was used to complete the criticality analysis for all contents, in particular, using the Criticality Safety Analysis Sequence with KENO-VI (CSAS6) [4]. The continuous energy cross section library ce_v7_endf was used, which compiles data from the ENDF/B-VII.0 data library.

SCALE is a comprehensive modeling and simulation suite for nuclear safety analysis and design developed and maintained by Oak Ridge National Laboratory under contract with the U.S. Nuclear Regulatory Commission, U.S. Department of Energy, and the National Nuclear Security Administration to perform reactor physics, criticality safety, radiation shielding, and spent fuel characterization for nuclear facilities and transportation/storage package designs.

Convergence of keff was determined through visual inspection of the plot of Average k-effective by Generation Run that is included in each output file. Convergence occurred when the moving average of keff did not appear to be increasing or decreasing upon conclusion of the run with respect to the final value of keff determined. Table 6.3.3-1 shows the typical neutron history specification used for each content. Some cases or studies of a content analysis required more neutron histories to achieve convergence.

Table 6.3.3-1. Neutron History Specification Number of Neutrons per Active Neutron Contents Generations Skipped Generation Histories Generations Standard 250 20000 50 4.0 x 106 Standard 450 10000 150 3.0 x 106 Hydrogen-Limited 5-inch Pipe 1650 2000 150 3.0 x 106 5-inch Pipe 1150 10000 150 1.0 x 107 Hydrogen-Limited 1S/2S UF6 450 10000 150 3.0 x 106 Cylinders Air Transport 600 10000 150 4.5 x 106 HCB 250 20000 50 4.0 x 106 6-30

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.4 Demonstration of Maximum Reactivity 6.3.4.1 Standard Configuration For the VP-55 standard configuration analysis, the desired Criticality Safety Index (CSI), thus the number of packages modeled, is fixed at 1.0. With the fixed number of packages, the following studies were done to determine the maximized fissile limit for each enrichment that results in keff less than the Upper Subcritical Limit (USL). These studies also demonstrate the subcriticality of the system and the acceptability 6.3.4.1.1 Homogeneous Fissile Shape Size Variation The first study done is the homogeneous fissile sphere size variation study. For a given 235U mass, the size of the fissile sphere is varied, which varies the amount of high-density polyethylene (HDPE) present in the fissile sphere, thereby altering the H/235U, thus, altering the neutron moderation. This is done for several fissile masses for each enrichment to determine the bounding, optimally moderated, homogeneous 235U mass limit with keff below the USL. For 1.25-wt.% enrichment, the radius of the Versa-Pac inner cavity is not large enough to model an optimally moderated sphere. Therefore, a cylindrical section is inserted between two hemispherical upper and lower end caps to achieve optimal moderation, as shown in Figure 6.3.4-1.

Because high-density polyethylene and metallic packing materials are limited in the inner cavity of the Versa-Pac by only the 350 lb payload weight limit of the package, this study examines the effect on keff of modeling these packing materials as inner cavity neutron reflectors. The reflector models are shown in Figure 6.3.4-2. For the HDPE study, the entire inner cavity is modeled as full-density HDPE and the H/235U curve is re-examined to determine optimal moderation. For evaluations, a HDPE volume fraction study is done to verify determine if any partial volume fractions of HDPE in the inner cavity result in an increase in keff over dry or full-density HDPE.

The metallic packing materials study is only performed for the single package evaluation to assess the effect of reflection from metallic contents. For this study, a steel reflector is modeled as close-fitting to the fissile mass sized to 350 lb. For both single package reflector studies (metallic and HDPE), the H/235U curve is re-examined to determine optimum moderation.

6.3.4.1.2 Heterogeneous Particle Fissile Shape Size Variation At lower enrichments, a heterogeneous array of fissile particles in a moderator lattice can be bounding of a homogeneous fissile-moderator mixture. Therefore, a heterogeneous particle study is performed to consider this effect. The heterogeneous fissile model is shown in Figure 6.3.4-1.

In the heterogeneous particle study, both the optimum moderation and optimum particle size are determined. For each fissile mass modeled, a range of particle sizes is examined to demonstrate the optimum particle size is determined. For each particle size, the particle pitch is varied, which varies the amount of moderator, thus varying the H/235U, to demonstrate optimal moderation for a particle size. The study is done for several fissile masses for each enrichment to determine

1) the bounding, optimally moderated 235U mass limit that is below the USL and 2) if a heterogeneous fissile-moderator system bounds a homogeneous system for a given enrichment.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.3.4-1. Fissile Mass Geometry. Homogeneous (left and center) and Heterogeneous (right).

Figure 6.3.4-2. Cavity Reflectors: Water, HDPE, and Steel (left to right).

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.4.1.3 Fissile Mass Position For the single package studies, the default position is the fissile mass centered in the inner cavity to maximize the neutron reflection from flooding water, HDPE, or steel. For the package array studies, the default fissile mass position is modeled as close together axially and radially to the other fissile masses in the array as the package allows, as shown in Figure 6.3.4-3. This is done to maximize neutron communication between the fissile masses of neighboring packages. In the fissile position study, the default fissile mass positions are verified as bounding by modeling the fissile masses in other positions. For the single package studies, the other positions in the inner cavity examined are 1) at the top, 2) at the bottom, and 3) at the top corner (i.e. pushed to the radial wall). For the package array studies, the other positions examined are 1) centered radially only, 2) centered axially only, and 3) centered both radially and axially.

Figure 6.3.4-3. Top (left) and Side Views (right) of the Default HAC Package Array Fissile Mass Positions.

6.3.4.1.4 Flooding For the HAC package array, a flooding study is done that examines various flooding configurations of the Versa-Pac, including preferential flooding and interspersed moderation. For all HAC package array studies except for the flooding study, all regions of the Versa-Pac are modeled as dry. The flooding configurations examined are shown in Figure 6.3.4-4: FLD1 is inner cavity-only flooding, FLD2 is outer cavity-only flooding, FLD3 is interspersed moderation only, and FLD4 is all regions flooded.

FLD1 FLD2 FLD3 FLD4 Figure 6.3.4-4. Top View of the Four HAC Flooding Configurations.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.4.1.5 Array Size Sensitivity For a CSI of 1.0 with N = 50, a 4x252 (i.e., a 4-package height by a total of 252 packages) NCT array and a 3x105 HAC array are the initial array sizes in this analysis. This study examines altering the height and configuration of packages (i.e., the number of packages in the x, y, and z directions) in an array to determine the bounding configuration. This study was done after all other studies for both NCT and HAC, including flooding. For NCT, additional array heights of three and five packages are examined. For HAC, additional array heights of two and four packages are examined.

With respect to rows and columns of packages, the array was modified to be longer in the +y and

+x directions separately, as shown in Figure 6.3.4-5 for the 2x high HAC package array. All other array sizes modeled are presented in Table 6.3.4-1 with their corresponding array indices. The convention used in this calculation note is to list the array height and then the array index, for brevity. So, the 5x high NCT array, second index is referred to as the 5-2 array (i.e., the 5 high, 9 by 6 array in Table 6.3.4-1). The array indices are used for clarity in presenting the results in Sections 6.5.1 and 6.6.1, with array indices as references to specific array configurations. Note that all NCT arrays model 252 packages and all HAC arrays model 105 packages. The array dimensions in Table 6.3.4-1 may not match the number of packages modeled because packages are removed from some rows to conserve the total number of packages between configurations.

The purpose of the array dimensions is to show the nominal rows and columns of the array layout and how the array shape changes. Thus, the number of packages per row listed is the maximum possible based on the size of the array boundary, shown in Figure 6.3.4-5.

Table 6.3.4-1. Array Index vs. Array Size Array NCT Array HAC Array Index Three High Four High Five High Two High Three High Four High 1 12 x 7 11 x 6 10 x 6 10 x 6 9x4 7x4 2 11 x 8 10 x 7 9x6 9x6 8x5 6x5 a

3 10 x 9 9x7 8x7 8x7 7 x 5a 5x6 4 9 x 10 8x8 7x8 7x8 6x6 4x7 5 8 x 11 7x9 6x9 6x9 5x7 3x9 Note: a This is the default array.

Figure 6.3.4-5. The 2x High HAC Package Array Configurations Examined.

6.3.4.1.6 Thorium Addition This study examines the addition of natural thorium to the fissile mass to demonstrate its effect on keff. The thorium is added to the fissile mass in 50 g increments without displacing any fissile or moderating material, i.e., the uranium mass and the HDPE mass remain constant, thus the H/235U is not altered. In the heterogeneous study, the fissile particle pitch is also altered to maintain the H/235U of a given fissile-moderator lattice.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.4.2 Hydrogen-Limited Contents Including TRISO Fuels These evaluations analyze hydrogen-limited contents based on a 1 lb limit on hydrogenous materials in the package, bounded by HDPE. This restriction is added to increase the fissile contents permitted in the package. Additionally, a more specific content definition is provided for TRISO fuel contents along with supplementary studies demonstrating that these contents are bounded by the homogeneous fissile sphere evaluation. Maximum enrichments of 100-, 20-, 10-,

and 5-wt.% 235U are specifically analyzed.

6.3.4.2.1 Homogeneous Fissile Mass Study Like the base Versa-Pac analyses, this analysis models a homogeneous mixture of fissile material and moderator in a spherical geometry. Multiple 235U masses are analyzed to demonstrate the sensitivity in keff to 235U mass and determine the maximum fissile mass resulting in keff below the USL. For each 235U mass, the size of the fissile sphere is increased by adding moderator to analyze varying moderation ratios and determine the point of optimal moderation. The difference in this analysis is that the HDPE moderator analyzed is limited to 1 lb (454 g) total. For the single package and HAC package array, the remainder of the additional moderator, beyond 1 lb of HDPE, is flooding water. Because the cavity remains dry during all NCT, for the NCT package array, no additional moderator is added to the fissile sphere beyond the maximum 1 lb of HDPE, which represents packing materials.

6.3.4.2.2 Heterogeneous Effects Study Two studies are performed to analyze the effects of a heterogeneous system in comparison to the homogeneous systems in the base analysis. Both studies analyze uranium metal particles suspended in a homogeneous moderator mixture. The first study is for the HAC package array and models a mixture of water and 1 lb of HDPE as the moderator and the second is for the NCT package array and models a mixture of graphite and 1 lb of HDPE as the moderator.

The HAC package array study examines particle sizes ranging from 0.00625 cm to 0.1 cm, for the CSI=0.7 array with the 605 g235U mass limit. The spherical uranium particles are modeled in a square-pitched, cuboid array that is bounded by a cylinder with H=D. The cylindrical bound is sized based on the particle volume and the pitch between the particles in the array to model the proper quantity of fissile material. Based on the particle radius of a respective case, the total number of particles required to model the total volume of uranium corresponding to the fissile material limit (605 g235U) is determined. The total volume of the cylinder bound corresponds to the total uranium volume scaled by the ratio of the unit cell total volume to the unit cell uranium volume. The height and diameter of the cylinder bound are calculated based on this total cylinder volume. This heterogeneous model is an approximation as there is no perfect fit for a cylindrical bound on the square pitched array, resulting in partial particles that are clipped by the bound.

However, the small size of the particles relative to the size of the array minimizes this effect, resulting in a modeled uranium mass that is very close to the limit. Note that the height and diameter of the cylinder bound are not exactly equal to avoid a scenario where a whole row of particles in the axial direction is clipped. Thus, the height is rounded to fully model all particles in the axial direction and the diameter is correspondingly adjusted to preserve the total volume of the cylinder.

In Section 6.6.2.2.3, the parameter labeled Pitch Ratio is a scaling factor applied to the particle radius to determine the pitch for the respective case. This maintains the same moderator to fuel ratios and resulting H/235U values analyzed for each particle size.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 The NCT particle array study examines a single particle size of 0.0425 cm, based on an approximate uranium kernel size in TRISO compacts, in the NCT array with the higher 635 g235U mass limit. The modeling of the particle array is similar to the HAC array study described above, but with a moderator mixture of graphite and 1 lb of HDPE.

The position and flooding studies for hydrogen-limited contents are done with the same method as with the standard configuration, as described in Sections 6.3.4.1.3 and 6.3.4.1.4, respectively.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.4.3 5-inch Pipe For this configuration, a scoping method manipulating several variablesfill percentage of the 5-inch pipe, package array configuration, U-235 enrichment, and H/U-235 ratiowas utilized to derive the mass limits presented in Table 6.2.3-1. Given a combination of fill percentage, array configuration, and U-235 enrichment, a plot of H/U-235s effect on keff was generated to determine the U-235 mass limit.

There were two different kinds of H/U-235 versus keff trend plots that were generated such that that one kind of chart produced values of keff + 2 that surpassed the USL and the second kind of chart did not. For 100- and 20-wt.% U-235, the trend plot had values of keff + 2 that surpassed the USL. As H/U-235 increases from zero towards infinity, the value of keff + 2 increases, peaks, and then decreases as it asymptotically approaches a value of keff + 2 of zero. In this process, the value of keff + 2 is equivalent to the USL at two separate values of H/U-235. The intersection of keff + 2 with the higher value of H/U-235 is the value of H/U-235 that results in the minimum U-235 mass and defines the mass limits presented.

For 10-wt.% U-235, the trend plots did not have values of keff + 2 that approached the USL. In these instances, the general shape of the plot would be the same as in the first kind of trend plot; however, no value of keff + 2 surpassed the USL. Therefore, it was concluded that 10-wt.% 235U is volume-limited by the 5-inch pipe. The studies presented in Sections 6.4.3, 6.5.3, and 6.6.3 confirm this conclusion.

Once the limiting U-235 mass limits were determined, several parameter studies were done to verify the sub-criticality of the limits proposed. These parameter studies involved varying the fill percentage of the inner container, varying the array configuration (package height of an array and overall array size), and analyzing partial fills. For the HAC package arrays, flooding studies were also performed for each enrichment level to determine its effect on keff.

The U-235 mass limits determined in the package array scoping were then applied to the single package analysis to verify the subcriticality of these U-235 limits in single packages. The single packages had three parameter studies: vary the fill percentage, partial fills, and partial U-235 mass.

The fissile material in this analysis was modeled as a single, form-fitting, homogeneous slug of uranium metal and high-density polyethylene that was able to occupy any z-axis position in the pipe container, as shown in Figure 6.3.4-6. For fill percentages less than 100, the slug was modeled at full density at a reduced height of the inner cavity of the pipe container, not as a reduced-density slug that would fill the entire inner volume of the pipe, as shown in Figure 6.3.4-8.

Figure 6.3.4-6. 5-Inch Pipe Container 45% Full in a VP-55 with HAC Damage 6-37

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 The bounding fissile positions determined in the standard configuration package array evaluations are used in the 5-inch pipe evaluations (see Section 6.3.4.1). The standard configuration evaluation modeled the fissile masses in an array in several different combinations of radial and axial positions in the inner cavity to determine the bounding position. The bounding configuration for an array with a height of four packages models the fissile masses of the first two package heights as tangent to the bottom z-surface of the containment and inverted those Versa-Pacs in the array. For the last two package heights, the fissile masses were modeled tangent to the bottom z-surface of the containment of non-inverted Versa-Pacs. This configuration is shown in Figure 6.3.4-7. The fissile masses are modeled in 5-inch pipe containers.

Figure 6.3.4-7. Side View of Bounding Fissile Positions for a 5-inch Pipe Package Array Note that the thicker parts of steel, related to the top of the package, are inverted in the two bottom rows of packages. This inversion of the packages was done to allow for greater neutron interaction through the thinner steel at the bottom of the package. This inversion was also done because all axial HAC damage modeled was applied to the bottom of the package, which further reduced the distance between fissile masses for the HAC cases.

The standard configuration evaluation also modeled optimum fissile mass placement in the x-y plane, which was evaluated by placing the fissile masses as close as possible to the centroid of a group of three packages arranged in a triangular pattern, as shown in Figure 6.3.4-8. The combined effect of optimum placement in both the z-direction and the x-y plane is what defined the bounding four-package-high array fissile positions.

Figure 6.3.4-8. Top View of Bounding Fissile Positions in the X-Y Plane 6-38

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.4.4 5-inch Pipe with Hydrogen-Limited Contents For this configuration, contents are analyzed for a CSI of 1.4 or 1.0, corresponding to HAC array sizes of 72 or 105 packages, respectively. The 10-wt% analysis includes two 5-inch pipes and the 20-wt% analysis includes one 5-inch pipe, and both impose a limit on hydrogenous materials to 1.25 lbs per pipe. Additionally, the 10 wt% analysis is split into two contents in the HAC array analysis one that models U-metal contents with a CSI=1.4 and one that models UO2 contents at a CSI=1.0. The Single package case models a package with HAC damage, fully flooded, with 20 cm of water reflection in each direction. The NCT package array analysis models a >5N (360 packages) array of packages with no flooding of the packages, but 20 cm of close water reflection in each direction of the array. The HAC package array analysis models a 2N array of packages with 20 cm of close water reflection in each direction of the array. Base geometries are shown below for the single package (Figure 6.3.4-9), HAC package array dual pipe, (Figure 6.3.4-10), and HAC package array single pipe (Figure 6.3.4-11) models to show the general configuration and positioning of the 5-inch pipe(s) and fissile material. In these figures, the dark blue material is the fissile contents, the light blue is water, and the green is packaging steel. Note that the positioning of the pipes in the NCT array is similar to the HAC array, just with more packages and the single package models one or two centered pipes, depending on enrichment.

The base analysis for each case considers a homogeneous mixture of the fissile and moderating contents. For any case where keff is near the USL, heterogeneous configurations are analyzed to determine if this change could result in keff exceeding the USL. For the homogeneous analyses, the 5-inch pipe(s) start with the first case modeled completely filled with Uranium or UO2. Each subsequent case reduces the volume of Uranium in the 5-inch pipe, replacing it first with 1.25 lb of HDPE then with water (for HAC/Single Package) or graphite (for NCT) depending on the condition analyzed. These studies demonstrate that the 5-inch pipes are volume limiting, so to add more moderator, the mass of fissile material must be reduced, thus, keff never exceeds the USL. For the heterogeneous analyses, the fissile contents are modeled as spherical particles, and the moderating material fills the interstitial space between the spheres. Multiple sphere sizes are analyzed and start close packed, completely filling the 5-inch pipe(s) with each case increasing the pitch between the particles. Similar to the homogeneous cases, the added interstitial space is filled with 1.25 lb HDPE and water.

Figure 6.3.4-9. Single Package 10 wt%235U Dual Pipe Geometry (Left - Side / Right - Top) 6-39

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.3.4-10. HAC Array 10 wt%235U Dual Pipe Geometry (Left - Side / Right - Top)

Figure 6.3.4-11. HAC Array 20 wt%235U Single Pipe Geometry (Left - Side / Right - Top) 6-40

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.4.5 1S/2S UF6 Cylinder In the 1S/2S UF6 cylinder analysis, the presence of UF6 cylinders modeled is dependent on the U-235 enrichment and transport condition, as shown in Table 6.3.4-2. For NCT analyses, it is assumed the 1S and 2S cylinders survive NCT and credit is taken for the confinement provided by the 1S and 2S cylinder assemblies. Water in-leakage is evaluated per 10 CFR 71.55 [2] and SSR-6 para. 680 [6]. Thus, the NCT calculational models considered an array of Versa-Pacs, each filled with water-moderated cylinders (sized to either a 1S or 2S), which are tight-packed and pushed against the cavity wall. For the HAC analyses, it is assumed that the 1S and 2S cylinders do not survive. Therefore, the contents assume the shape of a sphere for the 20-wt.%

U-235 analyses and the contents assume the shape of the 5-inch pipe for the 100-wt.% U-235 analyses.

Under NCT, all 1S and 2S cylinders as modeled take no credit for the cylinder pressure vessel material or valve presence, but do credit the spacing provided by the maximum outer dimensions of the pressure vessel diameter and cylinder assembly height, shown Figure 6.3.1-3. Under NCT, the homogeneous solution assumes the maximum outer height and diameter of its respective pressure vessel cylinder only, i.e. the valve is not included in the height of the solution cylinder.

For configurations where a UF6 cylinder is credited, groups of UF6 cylinders are modeled with flooding between cylinders and close, full-water reflection. The cylinder pitch and reflector thickness are independent variables in the analyses. See Figure 6.3.1-4 and Figure 6.3.1-5 for sketches of the two NCT cylinder groups as modeled.

Under HAC, no credit is taken for the confinement provided by 1S or 2S cylinders. For fissile contents with enrichment 20 wt.% U-235, the fissile contents take the form of a fissile sphere optimally moderated with water. For fissile contents with enrichment 100 wt.% U-235, the fissile contents take the form of a 5-inch pipe, with a separate 5-inch pipe for each UF6 cylinder in a single VP-55. As with the NCT analyses that credit the UF6 cylinders, the 5-inch pipes are modeled with flooding between 5-inch pipes and close, full-water reflection around the 5-inch pipe group, with pitch and reflector thickness as independent variables. The 5-inch pipe HAC configuration for 1S cylinders is shown in Figure 6.3.1-6. The 5-inch pipe HAC configuration for 2S cylinders is identical, except only one 5-inch pipe is modeled as only one 2S with enrichment 100 wt.% U-235 is allowed in a VP-55.

For all analyses, the fissile material is modeled in the form of a homogeneous uranyl fluoride (UO2F2) solution with water, as this is the most reactive credible form of UF6 in this analysis.

UO2F2 is formed when UF6 contacts water, and the nature of the compound results in a higher uranium density per unit volume than UF6. See Section 6.3.2.2 for the full explanation.

Table 6.3.4-2. Summary Table of 1S/2S Cylinder Modeling Configuration U-235 Cylinder Enrichment NCT HAC (wt.%)

3 cylinders in 3 100 3 cylinders 5-inch pipes 1S 7 cylinders as 20 7 cylinders fissile sphere 1 cylinder in 1 100 1 cylinder 5-inch pipe 2S 2 cylinders as 20 2 cylinders fissile sphere 6-41

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.4.5.1 Most Reactive 1S/2S Cylinder Configuration For each evaluation modeling cylinders or 5-inch pipes, studies vary the content spacing (when more than one cylinder/pipe was modeled), reflector thickness, the cylinder fill height, and the mass of uranium modeled. See Figure 6.3.1-4 for a representation of a 1S cylinder group, Figure 6.3.1-5 for a representation of a 2S cylinder group, and Figure 6.3.1-6 for a representation of 1S cylinders in 5-inch pipes. For each evaluation modeling a fissile sphere, studies vary the sphere size, thereby the H/U-235 ratio, and the mass of uranium modeled. Therefore, in both instances, the full combination of these variables was modeled and the most reactive case could be determined. To prove the most reactive case, each of these studies presented in this appendix are summarized results that show the individual effect of the variables on the most reactive case.

Table 6.3.4-3 and Table 6.3.4-4 show which of these studies were performed for each configuration. Not all studies were performed for each configuration; selection was based on the number of cylinders and/or pipes modeled and whether the contents survive HAC. Note that studies performed for all configurations, such as uranium mass reduction or cylinder/sphere position studies, are not shown in these tables.

Table 6.3.4-3. Single Package Studies for Each Configuration 20 wt.% 100 wt.%

Study A A 1S 2S 1SB 2SB Cylinder/5-inch Pipe Spacing -- -- X --

Cylinder/5-inch Pipe Fill Height -- -- X X Fissile Sphere Size X X -- --

Reduced U-235 Mass X X X X A B Note: Confinement boundary: sphere, 5-inch pipe.

Table 6.3.4-4. Package Array Studies for Each Configuration NCT HAC Study 20 wt.% 100 wt.% 20 wt.% 100 wt.%

a a a a c c 1S 2S 1S 2S 1S 2S 1Sb 2Sb Cylinder/5-inch Pipe Spacing X X X -- -- -- X --

Cylinder/5-inch Pipe Reflector X X X X -- -- X X Thickness Cylinder/5-inch Pipe Fill Height X X X X -- -- X X Fissile Sphere Size -- -- -- -- X X -- --

Reduced U-235 Mass X X X X X X X X Flooding Configuration -- -- -- -- X X X X Most Reactive Flooding Iteration -- -- -- -- X X X --

a b c Note: Confinement boundary UF6 Cylinder; 5-inch Pipe; sphere 6-42

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Cylinder/5-inch Pipe Spacing This study examines the effect on keff of the spacing between the cylinders in a cylinder group for those evaluations where at least one cylinder/5-inch pipe is modeled. By adjusting the spacing, the amount of water in the cylinder group, and therefore the moderation, is changed and its effect on keff determined. This variable is more significant for the NCT evaluations where the 1S or 2S cylinder model volume is too small, thereby not enough moderating material can be added to the volume of the cylinder model for the fissile solution to be optimally moderated. This variable is less significant for the 100 wt.% 5-inch pipe evaluations where optimal moderation can be achieved within the pipe volume. This study is not applicable to the HAC evaluations where the survival of the cylinder is not assumed, nor is there a 5-inch pipe confinement.

Cylinder/5-inch Pipe Reflector Thickness For the evaluations where at least one cylinder/5-inch pipe is modeled, this study examined the effect on keff of the thickness of the water reflector around the cylinder group. This study alters both neutron reflection and neutron communication between separate cylinder/pipe groups to determine whether the system is more under-moderated, requiring more reflection to increase keff, or more optimally moderated, requiring neutron communication to increase keff. This study is not applicable to the single package evaluations, as a fully flooded package is assumed. This study is also not applicable to the HAC evaluations where the survival of the cylinder is not assumed, nor is there a 5-inch pipe confinement.

Cylinder/5-inch Pipe Fill Height This study is applicable to the 100 wt.% NCT and HAC evaluations with the 5-inch pipe. By holding the fissile mass constant and adjusting the fill height of the cylinder/5-inch pipe, the amount of water in the pipe, and therefore the moderation, is adjusted. This study determines either the most reactive or the optimal fill height, which is dependent on the height of the cylinder/5-inch pipe.

Fissile Sphere Size For 20 wt.% HAC evaluations, where there is no 5-inch pipe, the fissile solution is modeled in the form of a sphere and its size is adjusted to determine the optimal moderation. By adjusting the size of the sphere while holding the fissile mass constant, the moderation in the sphere changes, affecting keff. The Versa-Pac inner cavity is big enough that optimal moderation is established for the fissile sphere cases without restriction of the sphere size.

Reduced U-235 Mass This study examined reducing the mass of U-235 modeled to determine the effect of partial fills on reactivity. For those evaluations where the fissile solution is under-moderated or the geometry is restrictive, a reduced quantity of U-235 can be more reactive. The dimensions of the fissile solutions determined in prior sections are not modified as the U-235 mass is reduced, which results in full-density water moderator replacing the subtracted U-235 mass.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Flooding Configuration For the HAC package array evaluation only, four separate flooding configurations were examined to determine the most reactive, credible flooding configuration. The study involved four configurations: flooding only the inner cavity of the Versa-Pac (FLD1), flooding only the outer cavity of the Versa-Pac (FLD2), flooding only the region between packages (interspersed moderation, FLD3), and flooding all interior and exterior regions of the Versa-Pac simultaneously (FLD4). Lower flooding densities were modeled by adjusting the volume fraction (VF) of the water from 0.0001 to 1.0. These four configurations are shown in Figure 6.3.4-12.

FLD1 FLD2 FLD3 FLD4 Figure 6.3.4-12. Top View of the HAC Flooding Configurations Most Reactive Flooding Iteration The default flooding configuration for all HAC evaluations was 0.0001 VF in all regions (FLD4). If another flooding configuration resulted in an increase in keff, any study of the cylinder spacing, reflector thickness, fill height, or uranium mass studies that had an H/235U vs. keff curve was repeated with the new flooding configuration to determine if there was an increase in keff. If there was an increase in keff, then the single new flooding configuration would be reanalyzed with the new, more reactive study case to ensure that the most reactive case had been determined. This most reactive case was then used in the sensitivity studies.

6.3.4.5.2 Sensitivity Studies Single Package Fissile Positioning Study For the most reactive cylinder configuration study of the single package evaluation, the group of cylinders was modeled as centered radially and axially inside the inner cavity of the Versa-Pac, as shown in Figure 6.3.4-13. For this study, several displacement configurations of the 1S/2S cylinder groups were examined to determine the effect on reactivity. The radial-only displacement case is shown in Figure 6.3.4-14 and the +z and -z axial displacement cases are shown in Figure 6.3.4-15.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.3.4-13. Top, Side Views of 1S Cylinder-Group Configuration - Single Package.

Figure 6.3.4-14. Top, Side Views of 1S Cylinder Group Radial Position - Single Package Figure 6.3.4-15. Top, Side Views of 1S Cylinder Group Axial Position Case - Single Package 6-45

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Package Array Fissile Positioning Study For the most reactive cylinder configuration study of the package array evaluation, the groups of 1S/2S cylinders were modeled as close together radially and axially as possible for maximum reactivity, as shown in Figure 6.3.4-16. For this study, different positions of the 1S/2S cylinder groups were analyzed to determine their effect on reactivity. Figure 6.3.4-17 shows the radially centered case, with the 2S cylinder groups maintaining their axial displacements. Figure 6.3.4-18 shows the axially centered case, with the 2S cylinder groups maintaining their radial displacements. Figure 6.3.4-19 shows the axially and radially centered case. This same spacing configuration was also used for the fissile sphere cases.

Figure 6.3.4-16. The Default 2S Cylinder Displacement - NCT Package Array Figure 6.3.4-17. The Radially Centered 2S Cylinder-Group Case - NCT Package Array 6-46

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.3.4-18. The Axially Centered 2S Cylinder-Group Case - NCT Package Array Figure 6.3.4-19. The Centered 2S Cylinder-Group Case - NCT Package Array 6-47

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Array Configuration For the package array evaluations, the configuration of the array was adjusted to verify that the array layouts modeled were the most reactive layouts possible. All NCT and HAC arrays in this calculation note model a CSI of 1.0, with at least 100 packages for HAC arrays and at least 250 packages for NCT arrays. To adjust the array configuration, the number of packages in the array was held constant as the package stacking height was adjusted, which resulted in a different number of packages per layer. The default NCT array is 252 packages stacked four packages high and the default HAC array is 105 packages stacked three packages high, as shown in Section 6.1.3. This study determined if other package stack heights were more reactive.

UF6 Fissile Solution Study All fissile material in this analysis is modeled as uranyl fluoride (UO2F2). This study verifies that the higher density of UO2F2 is more reactive by comparing the UO2F2 configurations with UF6.

See Section 6.3.2.2 for the material properties.

6.3.4.5.3 Case Naming Convention For 1S/2S cylinder contents, the case names provide information about the case analyzed. The most reactive NCT case for 1S cylinders has the case name VP-55_5IP_1S_100_HAC_UO2F2_

3x105_306_38.1_1_1_in, which has 9 separate parts: (1) VP-55 for Versa-Pac 55 variant, (2) 5IP for 5-inch pipe (not in all cases), (3) 1S for 1S cylinder, (4) HAC for hypothetical accident conditions, (5) UO2F2 for uranyl fluoride-H2O solution, (6) 3x105 for a 105-package array stacked three packages tall, (7) 306 for 306 grams of uranium per 1S cylinder, (8) 38.1_1_1 for a 38.1-cm fill height in the 5-inch pipe, 1 cm-thick reflector, and 1 cm pipe edge-to-pipe edge spacing, and (9) in, which represents that this input was created from a WORM script file. The sensitivity studies contain additional case name blocks, described as follows:

• FLDn represents flooding configuration study n.

• POS represents the fissile mass positioning study.

• UF6 represents the UF6 content material replacement sensitivity study.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.4.6 High-Capacity Basket Configuration For this configuration, contents are analyzed for a CSI of 1.4 or 0.7, corresponding to HAC array sizes (i.e., 2N) of 72 or 144 packages, respectively. All contents have a maximum enrichment of 20-wt.% and are split into uranium carbide (UC) with CSI=1.4 contents and uranium oxide (U3O8) with CSI=0.7 contents. The single package analysis models a single Versa-Pac with HAC damage, fully flooded, and 12 in. (30.48 cm) of water reflection in all directions. The NCT package array is modeled with 5N packages, no flooding, and 12 in. (30.48 cm) of water reflection in all directions. The HAC package array is modeled with 2N packages, no flooding in the initial studies, and with 12 in. (30.48 cm) of water reflection in all directions.

The base analysis for each evaluation considers a homogeneous mixture of the fissile and moderating contents. The homogeneous analysis models the bounding uranium compound for CSI=1.4 or 0.7 (Section 6.6.6.2). The homogeneous study starts with each 5-inch pipe completely full of the uranium compound. Uranium is incrementally removed and first, polyethylene is added in the uraniums place until the mass limit per pipe of 1.25 lb (567 g) is reached, then water is added to simulate flooding of the pipes. For the NCT array homogeneous evaluation, graphite is added instead of water. The heterogeneous study models spherical particles of the respective uranium compound within a water/polyethylene moderator in a square-pitch lattice. A wide range of particle sizes and particle pitches are modeled to cover a wide range of H/X values and verify that the peak keff is captured. Also, preferential flooding is examined for the bounding heterogeneous cases. The NCT package array and single package evaluations analyze only homogeneous configurations because they are both bounded by the homogeneous HAC array evaluation.

To allow for classifying the moderator and separator components of the HCB as Safety Category B, the analysis proves that the failure of any one of these components of the HCB basket will not negatively impact criticality safety. Thus, a study is done in the NCT and HAC array evaluations where the HCB is modeled missing either (a) one of two moderator pipes or (b) the separator plate. Because the HCBs in adjacent packages are rotated such that three adjacent moderating pipes are as close together as possible, the closest moderating pipe is the one removed in this study to bound any combination of HCB orientation and silo removal. Additionally, the NCT evaluation shows that both moderator pipes and the separator plate may all be missing and be acceptable. In the same study, the 5-inch pipes are also modeled as displaced axially out of their moderating pipes limited in their displacement by the containment foam plug. This study is done to verify the bounding position of the 5-inch pipe inside the Versa-Pac.

Geometries for the single package and HAC package array are shown in Figure 6.3.4-20 and Figure 6.3.4-21, respectively, showing the general positioning of the HCB and fissile material.

The NCT array is like the HAC array except larger to match the CSI and without any flooding, only water reflection around the array. The dark blue represents the fissile region, red is the moderating pipes, magenta is the separator plate, green is the packaging steel, light blue is reflecting water, and gold is flooding water.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.3.4-20. VP-55 with HCB Single Package Geometry (Top View / Side View)

Figure 6.3.4-21. VP-55 with HCB HAC Array Geometry (Top View / Side View) 6-50

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.3.4.6.1 HCB Moderator Pipe/Separator Plate Bounding Compound Analysis The HCB features two moderator pipes and a separator plate that are designed to reduce neutron communication between the 5-inch pipes in a single Versa-Pac and between multiple Versa-Pacs in an array. These components are made of CPVC, which was chosen for its Hydrogen and Chlorine content, as the scattering with Hydrogen and neutron capture in Chlorine reduce cross talk, thus, system reactivity. Additionally, the compound was selected for its higher allowable temperature and ability to retain Hydrogen and Chlorine at elevated temperatures. This compound is a complex polymer that is a combination of CPVC resin and additives for processability and to increase structural and thermal performance. For this analysis, a maximum of 5-wt.% Carbon black additive bounds all other compound additives. Therefore, the effect of the properties of the resin on keff must be quantified.

In this analysis, first, the optimal, homogeneous NCT array and HAC array cases are determined that will be used as the basis for the studies. Second, the Chlorine content and density of the CPVC are varied to determine the effect on keff, which is used to define the bounding compound.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4 Single Package Evaluation All contents fissile mass limits presented in Section 6.2 are determined in either the NCT package array evaluation in Section 6.5 or in the HAC package array evaluation in Section 6.6. The single package evaluation is done to verify these limits are subcritical in a fully flooded single package.

6.4.1 Standard Configuration This section verifies that the 235U mass limits determined in the array evaluations are subcritical in the single package evaluation. The single package is modeled with the HAC damage presented in Section 6.3.1, fully flooded, and reflected by at least 12 in. (30.48 cm) of full-density water. All fissile material is moderated by unlimited high-density polyethylene and is reflected by the fully flooded package. The single package configuration is shown in Figure 6.4.1-1.

Figure 6.4.1-1. Standard Configuration Model - Single Package 6-52

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.1.1 100-wt.% 235U The first study evaluates the 360 g235U fissile mass limit determined in the HAC package array evaluation in Section 6.6.1.1 for three different inner cavity reflectors: full-density water, full-density HDPE, and a 350-lb steel reflector with the remainder water. As shown in Table 6.4.1-1, the full-density HDPE reflector bounds water and steel for 100-wt.% 235U with keff + 2 of 0.92927, less than the USL of 0.9399. In addition, Figure 6.4.1-2 shows that the optimally moderated case is captured.

The second study compares the effect of homogeneous modeling of the fissile material-moderator mixture vs. heterogeneous modeling. As shown in Table 6.4.1-2 and Figure 6.4.1-3, homogeneous bounds heterogeneous for the 100-wt.% 235U single package. Also, Figure 6.4.1-4 shows that as the particle size decreases and the system approaches homogeneity, the bounding result approaches the homogeneous results.

The third study evaluates different positions of the fissile sphere in the inner cavity to verify the default, centered fissile position is bounding. As shown in Table 6.4.1-3, the default position is the bounding position for 100-wt.% 235U single package.

The final study examines the addition of up to 200 g of natural thorium to the fissile sphere. As shown in Table 6.4.1-4, adding natural thorium decreases keff marginally yet significantly.

Table 6.4.1-1. Homogeneous Fissile Mass - 100-wt.% 235U Standard Single Package keff + 2 Case Index Water HDPE 350 lb Steel 1 0.87628 0.89658 0.88650 2 0.90492 0.92109 0.91367 3 0.91243 0.92858 0.92010 4 0.91451 0.92927 0.92225 5 0.91455 0.92725 0.92052 6 0.91074 0.92342 0.91412 7 0.90387 0.91501 0.90551 8 0.88090 0.89054 --

Table 6.4.1-2. Heterogeneous Fissile Mass - 100-wt.% 235U Standard Single Package keff + 2 for Particle Radii - 360 g235U Pitch Ratio 0.003125 cm 0.00625 cm 0.0125 cm 0.025 cm 9.0 0.86536 0.85322 0.83379 0.78855 10.0 0.88500 0.87080 0.84307 0.78844 11.0 0.88752 0.86977 0.83569 0.77168 12.0 0.87602 0.85317 0.81629 0.74277 6-53

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.4.1-3. Fissile Mass Position - 100-wt.% 235U Standard Single Package Position keff + 2 Center 0.92927 Top 0.92697 Bottom 0.92701 Top Corner 0.92260 Table 6.4.1-4. Thorium Addition Study - 100-wt.% 235U Standard Single Package Thorium Mass keff + 2 (g) 0 0.92927 50 0.92768 100 0.92612 150 0.92334 200 0.92139 0.94 0.93 0.92 0.91 keff + 2 Water 0.9 HDPE 0.89 350lb Steel 0.88 0.87 200 400 600 800 1000 Fissile Sphere Radius (cm)

Figure 6.4.1-2. Homogeneous Fissile Shape - 100-wt.% 235U Standard Single Package 6-54

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.9 0.85 360g Hom.

keff + 2 0.003125 cm 0.8 0.00625 cm 0.0125 cm 0.75 0.025 cm 0.7 200 400 600 800 1000 H/U-235 Figure 6.4.1-3. Heterogeneous Fissile Shape - 100-wt.% 235U Standard Single Package 0.95 0.93 0.91 0.89 0.87 keff + 2 0.85 Het.

0.83 Hom.

0.81 0.79 0.77 0.75 0 0.005 0.01 0.015 0.02 0.025 0.03 Het. Particle Radius (cm)

Figure 6.4.1-4. Bounding Particle Results - 100-wt.% 235U Standard Single Package 6-55

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.1.2 20-wt.% 235U The first study evaluates the 445 g235U fissile mass limits determined in the NCT package array evaluation in Section 6.5.1.2 for three different inner cavity reflectors: full-density water, full-density HDPE, and a 350-lb steel reflector. As shown in Table 6.4.1-5, the full-density HDPE reflector bounds water and steel for 20-wt.% 235U with keff + 2 of 0.92660, less than the USL of 0.9416. In addition, Figure 6.4.1-5 shows that the optimally moderated case is captured.

The second study compares the effect of homogeneous modeling of the fissile material-moderator mixture vs. heterogeneous modeling. For this study, the inner cavity space is modeled as water.

As shown in Table 6.4.1-6 and Figure 6.4.1-6, homogeneous bounds heterogeneous for 20-wt.%

235 U single package. Also, Figure 6.4.1-7 shows that as the particle size decreases and the system approaches homogeneity, the bounding result approaches the homogeneous results.

The third study evaluates different positions of the fissile sphere in the inner cavity to verify the default, centered fissile position is bounding. As shown in Table 6.4.1-7, the default position is the bounding position for 20-wt.% 235U single package.

The final study examines the addition of up to 200 g of natural thorium to the fissile sphere. As shown in Table 6.4.1-8, adding natural thorium decreases keff marginally yet significantly.

Table 6.4.1-5. Homogeneous Fissile Mass wt.% 235U Standard Single Package keff + 2 Case Index Water HDPE 350 lb Steel 1 0.87978 0.89564 0.88386 2 0.90468 0.91891 0.90869 3 0.91227 0.92423 0.91467 4 0.91506 0.92660 0.91713 5 0.91461 0.92557 0.91728 6 0.91200 0.92175 0.91129 7 0.89707 0.90507 --

Table 6.4.1-6. Heterogeneous Fissile Mass wt.% 235U Standard Single Package Pitch keff + 2 for Particle Radii - 445 g235U Ratio 0.005 cm 0.015 cm 0.025 cm 0.035 cm 0.045 cm 5.75 0.89231 0.89221 0.88932 0.88150 0.87681 6.00 0.90045 0.89753 0.89381 0.88593 0.87939 6.25 0.90372 0.90137 0.89539 0.88637 0.87928 6.50 0.90495 0.90123 0.89334 0.88360 0.87464 6.75 0.90288 0.89797 0.88980 0.87668 0.86814 7.00 0.89864 0.89257 0.88174 0.87007 0.85933 7.25 0.89123 0.88412 0.87241 0.85982 0.84673 6-56

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.4.1-7. Fissile Mass Position wt.% 235U Standard Single Package Position keff + 2 Center 0.92660 Top 0.92517 Bottom 0.92526 Top Corner 0.92054 Table 6.4.1-8. Thorium Addition Study wt.% 235U Standard Single Package Thorium Mass keff + 2 (g) 0 0.92660 50 0.92495 100 0.92362 150 0.92249 200 0.92087 0.93 0.92 0.91 keff + 2 0.9 Water Poly 0.89 Steel 0.88 0.87 200 300 400 500 600 700 800 900 H/U-235 Figure 6.4.1-5. Homogeneous Fissile Shape wt.% 235U Standard Single Package 6-57

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.92 0.91 0.90 Hom.

0.89 keff + 2 0.005 cm 0.88 0.015 cm 0.87 0.025 cm 0.86 0.035 cm 0.85 0.045 cm 0.84 200 300 400 500 600 700 800 900 H/U-235 Figure 6.4.1-6. Heterogeneous Fissile Shape wt.% 235U Standard Single Package 0.92 0.915 0.91 0.905 0.9 keff + 2 0.895 Het.

0.89 Hom.

0.885 0.88 0.875 0.87 0 0.01 0.02 0.03 0.04 0.05 Particle Radius (cm)

Figure 6.4.1-7. Heterogeneous Bounding Particle wt.% 235U Standard Single Package 6-58

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.1.3 10-wt.% 235U The first study evaluates the 505 g235U fissile mass limit determined in the NCT package array evaluation in Section 6.5.1.3 for three different inner cavity reflectors: full-density water, full-density HDPE, and a 350-lb steel reflector. As shown in Table 6.4.1-9, the full-density HDPE reflector bounds water and steel for 10-wt.% 235U with keff + 2 of 0.91766, less than the USL of 0.9415. In addition, Figure 6.4.1-8 shows that the optimally moderated case is captured.

The second study compares the effect of homogeneous modeling of the fissile material-moderator mixture vs. heterogeneous modeling. For this study, the inner cavity space is modeled as water.

As shown in Table 6.4.1-10 and Figure 6.4.1-9, homogeneous bounds heterogeneous for 10-wt.%

235 U single package. Also, Figure 6.4.1-10 shows that the bounding particle size has been captured.

The third study evaluates different positions of the fissile sphere in the inner cavity to verify the default, centered fissile position is bounding. As shown in Table 6.4.1-11, the default position is the bounding position for 10-wt.% 235U single package.

The final study examines the addition of up to 200 g of natural thorium to the fissile sphere. As shown in Table 6.4.1-12, adding natural thorium decreases keff marginally yet significantly.

Table 6.4.1-9. Homogeneous Fissile Mass wt.% 235U Standard Single Package keff + 2 Case Index Water HDPE 350 lb Steel 1 0.86923 0.88435 0.86946 2 0.89524 0.90742 0.89636 3 0.90242 0.91477 0.90254 4 0.90647 0.91766 0.90630 5 0.90680 0.91628 0.90661 6 0.90440 0.91390 0.90442 7 0.90012 0.90907 0.89969 8 0.88313 0.89125 0.87814 Table 6.4.1-10. Heterogeneous Fissile Mass wt.% 235U Standard Single Package Pitch keff + 2 for Particle Radii - 505 g235U Ratio 0.005 cm 0.015 cm 0.025 cm 0.035 cm 0.045 cm 4.75 0.89229 0.89577 0.89900 0.89847 0.89664 5.00 0.89858 0.90218 0.90346 0.90252 0.89901 5.25 0.90046 0.90283 0.90419 0.90178 0.89794 5.50 0.89640 0.89891 0.89910 0.89594 0.89153 5.75 0.88903 0.89086 0.88954 0.88694 0.88126 6.00 0.87883 0.87960 0.87800 0.87353 0.86688 6.25 0.86468 0.86494 0.86210 0.85656 0.85048 6-59

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.4.1-11. Fissile Mass Position wt.% 235U Standard Single Package Position keff + 2 Center 0.91766 Top 0.91433 Bottom 0.91507 Top Corner 0.91186 Table 6.4.1-12. Thorium Addition Study wt.% 235U Standard Single Package Thorium Mass keff + 2 (g) 0 0.91766 50 0.91593 100 0.91378 150 0.91350 200 0.91199 0.93 0.92 0.91 0.9 keff + 2 Water 0.89 HDPE 0.88 Steel 0.87 0.86 200 400 600 800 1000 H/U-235 Figure 6.4.1-8. Homogeneous Fissile Shape wt.% 235U Single Package 6-60

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.91 0.90 0.89 Hom.

keff + 2 0.005 cm 0.88 0.015 cm 0.87 0.025 cm 0.035 cm 0.86 0.045 cm 0.85 200 400 600 800 1000 1200 H/U-235 Figure 6.4.1-9. Heterogeneous Fissile Shape wt.% 235U Standard Single Package 0.912 0.908 0.904 keff + 2 0.9 0.896 0.892 0 0.01 0.02 0.03 0.04 0.05 Het. Particle Radius (cm)

Figure 6.4.1-10. Heterogeneous Bounding Particle wt.% 235U Standard Single Package 6-61

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.1.4 5-wt.% 235U The first study evaluates the 610 g235U fissile mass limit determined in the NCT package array evaluation in Section 6.5.1.4 for three different inner cavity reflectors: full-density water, full-density HDPE, and a 350-lb steel reflector. As shown in Table 6.4.1-13, the full-density HDPE reflector bounds water and steel for 5-wt.% 235U with keff + 2 equal to 0.90009, less than the USL of 0.9417. In addition, Figure 6.4.1-11 shows that the optimally moderated case is captured.

The second study compares the effect of homogeneous modeling of the fissile material-moderator mixture vs. heterogeneous modeling. For this study, the inner cavity space is modeled as water.

As shown in Table 6.4.1-14 and Figure 6.4.1-12, heterogeneous bounds homogeneous for 5-wt.% 235U single package with a flooded inner cavity. Because both the HDPE inner cavity and heterogeneous are bounding, these two configurations are analyzed together. As shown in Table 6.4.1-15 and Figure 6.4.1-13, heterogeneous also bounds homogeneous for 5-wt.% 235U HDPE cavity single package, with keff + 2 equal to 90726, below the USL of 0.9417. Figure 6.4.1-14 also shows that HDPE bounds water and that the optimal particle size was captured.

The third study evaluates different positions of the fissile sphere in the inner cavity to verify the default, centered fissile position is bounding. As shown in Table 6.4.1-16, the default position is the bounding position for 5-wt.% 235U single package.

The final study examines the addition of up to 200 g of natural thorium to the fissile sphere. As shown in Table 6.4.1-17, adding natural thorium decreases keff marginally yet significantly.

Table 6.4.1-13. Homogeneous Fissile Mass wt.% 235U Standard Single Package keff + 2 Case Index Water HDPE 350 lb Steel 1 0.86801 0.87912 0.80567 2 0.87927 0.88985 0.84957 3 0.88602 0.89507 0.86464 4 0.89046 0.89949 0.87533 5 0.89191 0.90009 0.88363 6 0.88940 0.89790 0.88997 7 0.88032 0.88668 0.88911 8 -- -- 0.87915 Table 6.4.1-14. Heterogeneous Fissile Mass wt.% 235U Standard Single Package Pitch keff + 2 for Particle Radii - 610 g235U Ratio 0.0125 cm 0.025 cm 0.050 cm 0.075 cm 0.100 cm 3.75 0.87546 0.88110 0.88787 0.88968 0.88770 4.00 0.88779 0.89280 0.89701 0.89802 0.89618 4.25 0.89009 0.89506 0.89874 0.89788 0.89354 4.50 0.88546 0.88952 0.89133 0.89035 0.88372 4.75 0.87470 0.87869 0.87949 0.87501 0.86693 5.00 0.85893 0.86149 0.85970 0.85437 0.84548 6-62

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.4.1-15. Heterogeneous Fissile Mass with HDPE wt.% 235U Standard Single Package keff + 2 for Particle Radii - 610 g235U H/235U 0.0125 cm 0.025 cm 0.050 cm 0.075 cm 0.100 cm 3.75 0.88664 0.89201 0.89820 0.90042 0.89943 4.00 0.89642 0.90284 0.90615 0.90739 0.90382 4.25 0.89850 0.90261 0.90726 0.90540 0.90163 4.50 0.89180 0.89737 0.89916 0.89615 0.88991 4.75 0.88169 0.88444 0.88529 0.88172 0.87336 5.00 0.86442 0.86798 0.86562 0.86040 0.85158 Table 6.4.1-16. Fissile Mass Position wt.% 235U Standard Single Package Position keff + 2 Center 0.90726 Top 0.90082 Bottom 0.90158 Top Corner 0.89543 Table 6.4.1-17. Thorium Addition Study wt.% 235U Single Standard Package Thorium Mass keff + 2 (g) 0 0.90726 50 0.90507 100 0.90381 150 0.90359 200 0.90204 6-63

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.905 0.9 0.895 0.89 keff + 2 0.885 Water 0.88 Poly 0.875 350lb Steel 0.87 0.865 0.86 200 400 600 800 1000 H/U-235 Figure 6.4.1-11. Homogeneous Fissile Shape wt.% 235U Single Standard Package 0.91 0.9 0.89 Hom. Water 0.88 keff + 2 0.0125 cm 0.87 0.025 cm 0.05 cm 0.86 0.075 cm 0.85 0.1 cm 0.84 200 400 600 800 1000 1200 H/U-235 Figure 6.4.1-12. Heterogeneous Fissile Shape wt.% 235U Standard Single Package 6-64

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.92 0.91 0.9 Hom. HDPE 0.89 keff + 2 0.0125 cm 0.88 0.025 cm 0.87 0.05 cm 0.86 0.075 cm 0.85 0.1 cm 0.84 200 400 600 800 1000 1200 H/U-235 Figure 6.4.1-13. Heterogeneous Fissile Shape with HDPE wt.% 235U Standard Single Package 0.91 0.906 0.902 keff + 2 Water 0.898 HDPE 0.894 0.89 0 0.02 0.04 0.06 0.08 0.1 0.12 Het. Particle Radius (cm)

Figure 6.4.1-14. Bounding Particle Results wt.% 235U Standard Single Package 6-65

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.1.5 1.25-wt.% 235U The first study evaluates the 1650 g235U fissile mass limit determined in the NCT package array evaluation in Section 6.5.1.5 for three different inner cavity reflectors: full-density water, full-density HDPE, and a 350-lb steel reflector. As shown in Table 6.4.1-18, the full-density HDPE reflector bounds water and steel for 1.25-wt.% 235U with keff + 2 equal to 0.82206, less than the USL of 0.9423. In addition, Figure 6.4.1-15 shows that the optimally moderated case is captured.

The second study compares the effect of homogeneous modeling of the fissile material-moderator mixture vs. heterogeneous modeling. For this study, the inner cavity space is modeled as water.

As shown in Table 6.4.1-19 and Figure 6.4.1-16, heterogeneous bounds homogeneous for 1.25-wt.% 235U single package with a flooded inner cavity. Because both the HDPE inner cavity and heterogeneous are bounding, these two configurations are analyzed together. As shown in Table 6.4.1-20 and Figure 6.4.1-17, heterogeneous bounds homogeneous for 1.25-wt.% 235U HDPE cavity single package, with keff + 2 equal to 0.86759, below the USL of 0.9423. Figure 6.4.1-18 also shows that HDPE bounds water and that the optimal particle size was captured for 1.25-wt.% single package.

The third study evaluates different positions of the fissile sphere in the inner cavity to verify the default, centered fissile position is bounding. As shown in Table 6.4.1-21, the default position is the bounding position for 1.25-wt.% 235U single package.

The final study examines the addition of up to 200 g of natural thorium to the fissile sphere. As shown in Table 6.4.1-22, adding natural thorium decreases keff marginally yet significantly.

Table 6.4.1-18. Homogeneous Fissile Mass - 1.25-wt.% 235U Standard Single Package keff + 2 Case Index Water HDPE 350 lb Steel 1 0.81117 0.81351 0.80450 2 0.81687 0.81952 0.81223 3 0.82022 0.82206 0.81550 4 0.82003 0.82156 0.81683 5 0.81863 0.81970 0.81583 6 0.81588 0.81665 0.81388 7 0.81149 0.81278 0.80923 Table 6.4.1-19. Heterogeneous Fissile Mass - 1.25-wt.% 235U Standard Single Package Pitch keff + 2 for Particle Radii - 1650 g235U Ratio 0.20 cm 0.30 cm 0.35 cm 0.40 cm 0.50 cm 2.65 0.85191 0.85840 0.86057 0.86176 0.86000 2.70 0.85459 0.86205 0.86263 0.86300 0.86098 2.75 0.85762 0.86347 0.86459 0.86349 0.86026 2.80 0.85898 0.86324 0.86364 0.86325 0.85883 2.85 0.85867 0.86285 0.86250 0.86043 0.85726 2.90 0.85764 0.85989 0.85968 0.85796 0.85283 2.97 0.85517 0.85676 0.85449 0.85300 0.84579 6-66

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.4.1-20. Heterogeneous Fissile Mass with HDPE - 1.25-wt.% 235U Standard Single Package keff + 2 for Particle Radii - 1650 g235U H/235U 0.20 cm 0.30 cm 0.35 cm 0.40 cm 0.50 cm 2.65 0.85606 0.86297 0.86474 0.86526 0.86453 2.70 0.85779 0.86476 0.86562 0.86659 0.86479 2.75 0.86085 0.86545 0.86759 0.86627 0.86387 2.80 0.86053 0.86495 0.86579 0.86513 0.86194 2.85 0.86064 0.86380 0.86446 0.86271 0.85836 2.90 0.85946 0.86167 0.86095 0.85973 0.85444 2.97 0.85588 0.85724 0.85600 0.85339 0.84666 Table 6.4.1-21. Fissile Mass Position - 1.25-wt.% 235U Standard Single Package Position keff + 2 Center 0.86759 Top 0.86430 Bottom 0.86451 Top Corner 0.86321 Table 6.4.1-22. Thorium Addition Study - 1.25-wt.% 235U Standard Single Package Thorium Mass keff + 2 (g) 0 0.86759 50 0.86674 100 0.86620 150 0.86541 200 0.86488 6-67

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.824 0.822 0.82 0.818 0.816 keff + 2 0.814 Water 0.812 HDPE 0.81 0.808 350lb Steel 0.806 0.804 0.802 400 500 600 700 800 900 H/U-235 Figure 6.4.1-15. Homogeneous Fissile Shape - 1.25-wt.% 235U Standard Single Package 0.87 0.86 0.85 0.2 cm 0.84 keff + 2 0.3 cm 0.83 0.35 cm 0.4 cm 0.82 0.5 cm 0.81 Hom. Water 0.8 350 450 550 650 750 850 H/U-235 Figure 6.4.1-16. Heterogeneous Fissile Shape - 1.25-wt.% 235U Single Standard Package 6-68

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.88 0.87 0.86 0.2 cm 0.85 keff + 2 0.3 cm 0.84 0.35 cm 0.83 0.4 cm 0.82 0.5 cm 0.81 Hom. HDPE 0.8 350 450 550 650 750 850 H/U-235 Figure 6.4.1-17. Heterogeneous Fissile Shape with HDPE - 1.25-wt.% 235U Standard Single Package 0.875 0.87 keff + 2 0.865 Water HDPE 0.86 0.855 0.1 0.2 0.3 0.4 0.5 0.6 Het. Particle Radius (cm)

Figure 6.4.1-18. Heterogeneous Bounding Particle - 1.25-wt.% 235U Single Standard Package 6-69

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.2 Hydrogen-Limited Contents Including TRISO Fuels For the hydrogen-limited contents single package analysis, the fissile sphere is modeled in the center of the cavity with all regions of the package fully flooded and 12 inches of water modeled around the package for full reflection. To demonstrate subcriticality of the system for a single package in isolation, moderation curves are developed for multiple 235U masses based on the bounding fissile mass determined in the HAC array analyses.

6.4.2.1 100-wt.% 235U The results of the 100-wt.% 235U single package evaluation are shown in Table 6.4.2-1 and Figure 6.4.2-1. The target 235U mass of 515 g is based on the HAC package array analyses in Section 6.6.2. Varied 235U masses are analyzed to show the sensitivity in keff from the 235U mass. For a single package in isolation, the single package evaluation shows that there is significant margin between the maximum value of keff and the USL.

Table 6.4.2-1. 100-wt.% 235U Hydrogen Limited Content Single Package Results Fissile Radius keff + 2 for Fissile Spheres (cm) 505 g 510 g 515 g 520 g 525 g 11 0.88131 0.88175 0.88432 0.88491 0.88788 12 0.89690 0.89880 0.90023 0.90374 0.90405 13 0.90364 0.90535 0.90699 0.90970 0.91265 14 0.89948 0.90108 0.90443 0.90671 0.90980 15 0.88743 0.89017 0.89283 0.89548 0.89901 0.915 0.91 0.905 0.9 505 g k-eff + 2s 0.895 510 g 0.89 515 g 520 g 0.885 525 g 0.88 0.875 10 11 12 13 14 15 16 Fissile Sphere Radius (cm)

Figure 6.4.2-1. 100-wt.% 235U Hydrogen Limited Content Single Package Results 6-70

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.2.2 20-wt.% 235U The results of the 20-wt.% 235U single package evaluation are shown in Table 6.4.2-2 and Figure 6.4.2-2. The target 235U mass of 635 g is based on the higher limit from the CSI=1.0 cases in the HAC package array analyses in Section 6.6.2. Varied 235U masses are analyzed to show the sensitivity in keff from the 235U mass. For a single package in isolation, the single package evaluation shows that there is significant margin between the maximum value of keff and the USL.

Table 6.4.2-2. 20-wt.% 235U Hydrogen Limited Content Single Package Results Fissile Radius keff + 2 for Fissile Spheres (cm) 625 g 630 g 635 g 640 g 645 g 12 0.87627 0.87847 0.87834 0.87897 0.87987 13 0.89362 0.89564 0.89648 0.89830 0.89840 14 0.90156 0.90324 0.90502 0.90656 0.90763 15 0.90068 0.90169 0.90322 0.90540 0.90670 16 0.89189 0.89307 0.89583 0.89765 0.89907 0.91 0.905 0.9 0.895 625 g k-eff + 2s 0.89 630 g 0.885 635 g 640 g 0.88 645 g 0.875 0.87 11 12 13 14 15 16 17 Fissile Sphere Radius (cm)

Figure 6.4.2-2. 20-wt.% 235U Hydrogen Limited Content Single Package Results 6-71

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.2.3 10-wt.% 235U The results of the 10-wt.% 235U single package evaluation are shown in Table 6.4.2-3 and Figure 6.4.2-3. The target 235U mass of 685 g is based on the HAC package array analyses in Section 6.6.2. Varied 235U masses are analyzed to show the sensitivity in keff from the 235U mass. For a single package in isolation, the single package evaluation shows that there is significant margin between the maximum value of keff and the USL.

Table 6.4.2-3. 10-wt.% 235U Hydrogen Limited Content Single Package Results Fissile Radius keff + 2 for Fissile Spheres (cm) 675 g 680 g 685 g 690 g 695 g 13 0.86896 0.86962 0.87076 0.87215 0.87212 14 0.88125 0.88313 0.88407 0.88459 0.88641 15 0.88574 0.88625 0.88834 0.88902 0.88995 16 0.88156 0.88287 0.88354 0.88535 0.88709 17 0.86955 0.87216 0.87400 0.87369 0.87740 0.895 0.89 0.885 675 g k-eff + 2s 0.88 680 g 685 g 0.875 690 g 0.87 695 g 0.865 12 13 14 15 16 17 18 Fissile Sphere Radius (cm)

Figure 6.4.2-3. 10-wt.% 235U Hydrogen Limited Content Single Package Results 6-72

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.2.4 5-wt.% 235U The results of the 5-wt.% 235U single package evaluation are shown in Table 6.4.2-4 and Figure 6.4.2-4. The target 235U mass of 800 g is based on the HAC package array analyses in Section 6.6.2. Varied 235U masses are analyzed to show the sensitivity in keff from the 235U mass. For a single package in isolation, the single package evaluation shows that there is significant margin between the maximum value of keff and the USL.

Table 6.4.2-4. 5-wt.% 235U Hydrogen Limited Content Single Package Results Fissile Radius keff + 2 for Fissile Spheres (cm) 790 g 795 g 800 g 805 g 810 g 14 0.84954 0.85102 0.85117 0.85149 0.85267 15 0.86215 0.86323 0.86305 0.86461 0.86576 16 0.86599 0.86718 0.86843 0.86884 0.87049 17 0.86240 0.86367 0.86518 0.86685 0.86709 18 0.85229 0.85450 0.85625 0.85676 0.85908 0.875 0.87 0.865 790 g k-eff + 2s 0.86 795 g 800 g 0.855 805 g 0.85 810 g 0.845 13 14 15 16 17 18 19 Fissile Sphere Radius (cm)

Figure 6.4.2-4. 5-wt.% 235U Hydrogen Limited Content Single Package Results 6-73

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 As shown in Table 6.4.2-5 and Figure 6.4.2-5, modeling 800 g235U at an enrichment of 5-wt.%

235 U with particle radii from 0.0125 to 0.2 cm shows that the heterogeneous configuration is bounding of the homogeneous configuration. A heterogeneous particle size of 0.05 cm with a particle pitch of 0.21875 cm results in the bounding with keff + 2 = 0.87591. Therefore, the 5-wt.%

235 U hydrogen-limited mass limit of 800 g235U is subcritical in the single package evaluation.

Table 6.4.2-5. 5-wt.% 235U Particle Size Study Hydrogen Limited Content Single Package Pitch keff + 2 for Particle Size Ratio 0.0125 cm 0.025 cm 0.05 cm 0.1 cm 0.2 cm 3.875 0.85125 0.85604 0.86210 0.86433 0.85753 4 0.85808 0.86205 0.86962 0.87033 0.85925 4.125 0.86191 0.86670 0.87312 0.87344 0.86005 4.25 0.86505 0.87010 0.87441 0.87376 0.85827 4.375 0.86685 0.87253 0.87591 0.87343 0.85561 4.5 0.86683 0.87276 0.87558 0.87197 0.85064 4.625 0.86487 0.86964 0.87334 0.86760 0.84615 4.75 0.86250 0.86703 0.86959 0.86281 0.83761 4.875 0.85960 0.86195 0.86357 0.85653 0.82825 Note: A All case names are prefixed VP-55_U_. The case names were shortened here for brevity. In addition, x represents the particle size (1 for 0.0125 cm and 5 for 0.2 cm).

0.88 0.875 0.87 0.0125 cm 0.865 k-eff + 2s 0.025 cm 0.86 0.05 cm 0.855 0.1 cm 0.85 0.2 cm 0.845 Hom.

0.84 300 400 500 600 700 800 H/U-235 Figure 6.4.2-5. 5-wt.% 235U Particle Size Study Hydrogen Limited Content Single Package 6-74

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.3 5-inch Pipe For the single package, the 5-inch pipe container is modeled as resting at the bottom of the containment and centered radially. Table 6.4.3-1 provides a summary of the limiting cases from the Single Package Evaluation. As shown, keff + 2 for all enrichments are below the USL, verifying the subcriticality of single packages under NCT and HAC.

Table 6.4.3-1. Summary of the Single Package Evaluation of the VP-55 with 5-inch Pipe Container U-235 U-235 Mass Fill Case keff + 2 USL Enrichment (g) Percentage VP-55_5IP_HAC_100WT_SIN_VF055 100 695 55 0.86526 0.9399 VP-55_5IP_HAC_20WT_SIN_VF085 20 1215 85 0.83378 0.9416 VP-55_5IP_HAC_10WT_SIN_VF100 10 1605 100 0.78956 0.9394 6.4.3.1 Variation of Fill Parameter Study - Single Package Results To determine the limiting fill percentage of a single package, the limiting fissile masses were held constant as the fill percentage of the 5-inch pipe container was varied. This change in fill percentage resulted in a variation of the amount of high-density polyethylene (HDPE) moderator, thus a variation of the H/U-235 ratio. Case VP-55_5IP_HAC_100WT_SIN_VF045 is a case that models the Versa-Pac 55-gallon version (VP-55) under Hypothetical Accident Conditions (HAC),

with 100-wt.% U-235 enriched uranium (100WT) as a single package (SIN), in the Variation of Fill parameter study (VF) and with a 5-inch pipe fill percentage of 45% (045). Table 6.4.3-2 shows the values of keff and for the different fill percentages examined. Note the most limiting fill percentages are highlighted. The fill percentage trends for each enrichment level are plotted in Figure 6.4.3-1. The limiting fill percentages are:

• For U(100), the limiting fill percentage is 55 with a value of keff + 2 of 0.86562. This fill percentage is optimally moderated as evidenced by the peak in keff.

• For U(20), the limiting fill percentage is 85 with a value of keff + 2 of 0.83378. This fill percentage is optimally moderated as evidenced by the peak in keff.

• For U(10), the limiting fill percentage is 100 with a value of keff + 2 of 0.78956. As a peak in keff is not present for U(10), this shows that keff for U(10) is not optimally moderated and is volume-limited by the 5-inch pipe.

6-75

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.4.3-2. Fill Percentage Sensitivity of the 5-Inch Pipe Container - Single Package U-235 Fill Case H/U-235 keff keff + 2 Mass (g) Percentage 100-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_100WT_SIN_VF045 695 45 146.42 0.8585 0.00059 0.85968 VP-55_5IP_HAC_100WT_SIN_VF050 695 50 162.88 0.86235 0.00061 0.86357 VP-55_5IP_HAC_100WT_SIN_VF055 695 55 179.34 0.86412 0.00057 0.86526 VP-55_5IP_HAC_100WT_SIN_VF060 695 60 195.80 0.86371 0.00056 0.86483 VP-55_5IP_HAC_100WT_SIN_VF065 695 65 212.26 0.86078 0.00052 0.86182 20-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_20WT_SIN_VF075 1215 75 132.61 0.83095 0.00057 0.83209 VP-55_5IP_HAC_20WT_SIN_VF080 1215 80 142.03 0.83226 0.00053 0.83332 VP-55_5IP_HAC_20WT_SIN_VF085 1215 85 151.44 0.83274 0.00052 0.83378 VP-55_5IP_HAC_20WT_SIN_VF090 1215 90 160.86 0.83179 0.00057 0.83293 VP-55_5IP_HAC_20WT_SIN_VF095 1215 95 170.27 0.83232 0.00051 0.83334 10-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_10WT_SIN_VF080 1605 80 96.80 0.7764 0.00048 0.77736 VP-55_5IP_HAC_10WT_SIN_VF085 1605 85 103.93 0.78057 0.0005 0.78157 VP-55_5IP_HAC_10WT_SIN_VF090 1605 90 111.05 0.78367 0.00051 0.78469 VP-55_5IP_HAC_10WT_SIN_VF095 1605 95 118.18 0.78605 0.00057 0.78719 VP-55_5IP_HAC_10WT_SIN_VF100 1605 100 125.31 0.78852 0.00052 0.78956 0.87 0.86 0.85 0.84 0.83 keff + 2 0.82 100-wt.%

0.81 20-wt.%

0.8 10-wt.%

0.79 0.78 0.77 40 50 60 70 80 90 100 Fill Percentage Figure 6.4.3-1. Fill Percentage Sensitivity inch Pipe Single Package 6-76

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.3.2 Partial Fill Parameter Study - Single Package Results For the partial fill of single packages parameter study, the limiting H/U-235 ratio of each enrichment level was held constant as the fill percentage of the 5-inch pipe container was varied to examine the effect of partial fills on the value of keff. This study shows that the fill percentage modeled is the limiting fill percentage for the limiting H/U-235 ratio identified. A decrease in keff + 2 for all partial fills is the expected behavior if the limiting fill percentage has been properly identified.

Case VP-55_5IP_HAC_100WT_SIN_PF005 models the Partial Fill (PF) parameter study with the five-inch pipe container 5% full (005). The partial fills percentages in this study are referred to absolutely; that is, relative to a full pipe. They are not relative to the most limiting fill percentage determined in the variation of fill parameter study. In this study, Partial Fill 5 (PF005) is five percent full of the entirety of the pipe, not five percent of the limiting fill percentage as determined.

Table 6.4.3-3 shows the values of keff and for the partial fills examined. As the fill percentage is reduced with the limiting H/U-235 held constant, the value of keff + 2 also reduces, as shown.

This shows that partial fills are not more limiting than the limiting fill percentages as determined in the Variation of Fill parameter study. Note the limiting cases are highlighted. The partial fill trends for each enrichment level are plotted in Figure 6.4.3-2.

Table 6.4.3-3. Partial Fill Sensitivity of the 5-Inch Pipe Container - Single Package Fill U-235 Case H/U-235 keff keff + 2 Percentage Mass (g) 100-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_100WT_SIN_PF005 5 63.18 179.34 0.29849 0.00036 0.29921 VP-55_5IP_HAC_100WT_SIN_PF015 15 189.55 179.34 0.58926 0.00054 0.59034 VP-55_5IP_HAC_100WT_SIN_PF025 25 315.91 179.34 0.72466 0.00052 0.72570 VP-55_5IP_HAC_100WT_SIN_PF035 35 442.27 179.34 0.79661 0.00051 0.79763 VP-55_5IP_HAC_100WT_SIN_PF045 45 568.64 179.34 0.83756 0.00058 0.83872 VP-55_5IP_HAC_100WT_SIN_PF055 55 695.00 179.34 0.86412 0.00057 0.86526 20-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_20WT_SIN_PF010 10 142.94 151.44 0.44433 0.00043 0.44519 VP-55_5IP_HAC_20WT_SIN_PF030 30 428.82 151.44 0.70711 0.00051 0.70813 VP-55_5IP_HAC_20WT_SIN_PF050 50 714.71 151.44 0.7855 0.00051 0.78652 VP-55_5IP_HAC_20WT_SIN_PF070 70 1000.59 151.44 0.81943 0.00053 0.82049 VP-55_5IP_HAC_20WT_SIN_PF080 80 1143.53 151.44 0.82884 0.00053 0.82990 VP-55_5IP_HAC_20WT_SIN_PF085 85 1215.00 151.44 0.83274 0.00052 0.83378 10-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_10WT_SIN_PF010 10 160.50 125.31 0.42124 0.00043 0.42210 VP-55_5IP_HAC_10WT_SIN_PF030 30 481.50 125.31 0.66081 0.00049 0.66179 VP-55_5IP_HAC_10WT_SIN_PF050 50 802.50 125.31 0.7343 0.00051 0.73532 VP-55_5IP_HAC_10WT_SIN_PF070 70 1123.50 125.31 0.76757 0.00054 0.76865 VP-55_5IP_HAC_10WT_SIN_PF090 90 1444.50 125.31 0.78307 0.00051 0.78409 VP-55_5IP_HAC_10WT_SIN_PF100 100 1605.00 125.31 0.78852 0.00052 0.78956 6-77

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.9 0.8 0.7 0.6 keff + 2 100-wt.%

0.5 20-wt.%

0.4 10-wt.%

0.3 0.2 0 20 40 60 80 100 Partial Fill (%)

Figure 6.4.3-2. Partial Fill Sensitivity inch Pipe Single Package 6-78

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.3.3 Partial U-235 Mass Study - Single Package Results The partial U-235 mass parameter study under HAC was performed for only U(10) due to the fact that this enrichment levels limit-defining case was with the 5-inch pipe container 100% full, so it could not be concluded as to whether or not it was optimally moderated. To evaluate this case, the limiting fill percentage of 100% was held constant as the mass of U-235 was reduced, similar to the partial fill evaluation. Additional HDPE moderator was added to take up the missing space due to a lesser mass of U-235. This study was done to determine the effect on keff of increasing H/U-235 as the mass of U-235 was reduced. Case VP-55_5IP_HAC_10WT_SIN_PF1_090 models the Partial U-235 Mass (PF1) sensitivity study with the 5-inch pipe container 100% full and only 90% of the bounding U-235 mass of 1605 g (90). Table 6.4.3-4 shows the values of keff and for the partial U-235 masses examined. Figure 6.4.3-3 plots the information for visual inspection of the trend. As the U-235 mass is reduced while the limiting fill percentage of 100%

is held constant, the value of keff + 2 also reduces. This shows that partial U-235 masses with higher values of H/U-235 are not more limiting than the limiting fill percentage at 100% full as identified. Note the limit-defining case is highlighted.

Table 6.4.3-4. Partial U-235 Mass Sensitivity of 5-Inch Pipe Container - Single Package

% of U-235 U-235 Case H/U-235 keff keff + 2 Mass Limit Mass (g)

VP-55_5IP_HAC_10WT_SIN_PF1_090 90 1444.50 141.15 0.78574 0.00053 0.78680 VP-55_5IP_HAC_10WT_SIN_PF1_095 95 1524.75 132.81 0.78660 0.00052 0.78764 VP-55_5IP_HAC_10WT_SIN_PF1_100 100 1605.00 125.31 0.78852 0.00052 0.78956 0.798 0.793 keff + 2 0.788 0.783 0.778 90 92 94 96 98 100 Percentage of Bounding U-235 Mass Figure 6.4.3-3: Partial U-235 Mass Sensitivity - U(10) 5-inch Pipe Single Package 6-79

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.4 5-inch Pipe with Hydrogen-Limited Contents The results of the Single Package analysis for the 5-inch Pipe with Hydrogen-Limited contents are provided below in Table 6.4.4-1. The cases for the 10 wt% analysis model two pipes centered in the cavity and the cases for the 20 wt% analysis model one pipe centered in the cavity. Each analysis starts with a pipe entirely filled with U-metal. The second case in each (VFU=0.916) corresponds to 1.25 lbs of HDPE and the remainder of the pipe filled with U-metal. Each of the following cases reduce the quantity of U-metal in the pipes and replace it with water to analyze a full range of moderation ratios and determine the peak value of keff. The results of these cases are plotted for each enrichment in Figure 6.4.4-1 and Figure 6.4.4-2. The Single Package analysis for this content demonstrates that there is a large margin to the USL for all cases.

Table 6.4.4-1. Summary 5-inch Pipe Hydrogen Limited Content Single Package Criticality Evaluation 10 wt% 20 wt%

Case a VFU H/X k+2s H/X k+2s SIN_X_01 1.000 0.0 0.68423 0.0 0.71423 SIN_X_02 0.916 1.6 0.70228 0.8 0.72497 SIN_X_03 0.800 3.8 0.71891 1.9 0.73148 SIN_X_04 0.600 9.6 0.74536 4.8 0.73816 SIN_X_05 0.400 21.3 0.77624 10.6 0.74422 SIN_X_06 0.200 56.2 0.80845 28.1 0.75760 SIN_X_07 0.180 64.0 0.80964 32.0 0.75869 SIN_X_08 0.160 73.7 0.80980 36.8 0.76024 SIN_X_09 0.140 86.2 0.80873 43.1 0.76059 SIN_X_10 0.120 102.8 0.80517 51.4 0.76016 SIN_X_11 0.100 126.1 0.79821 63.0 0.75866 SIN_X_12 0.080 161.0 0.78453 80.5 0.75309 SIN_X_13 0.060 219.3 0.75832 109.6 0.74149 SIN_X_14 0.040 335.7 0.70754 167.9 0.71405 Note: a Placeholder X replaced by 010 for 10 wt% results or 020 for 20 wt% results.

6-80

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.90 0.85 0.80 keff + 2s 0.75 0.70 0.65 0.60 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Volume Fraction U Figure 6.4.4-1. 10 wt% 5-inch Pipe Hydrogen Limited Content Single Package Results 0.80 0.78 0.76 0.74 keff + 2s 0.72 0.70 0.68 0.66 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Volume Fraction U Figure 6.4.4-2. 20 wt% 5-inch Pipe Hydrogen Limited Content Single Package Results 6-81

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.5 1S/2S Cylinder All single packages are modeled under HAC. As discussed in Section 6.3.4.5, for HAC, the cylinders are not assumed to survive, thus, the fissile contents take the form of a homogeneous sphere of fissile and moderating materials for 20-wt.% 235U and take the form of a homogeneous slug of fissile and moderating material inside a 5-inch pipe for 100-wt.% 235U.

Table 6.4.5-1. Summary Table of 1S Cylinder Single Package Criticality Evaluation Max. Maximum Bounding Configuration keff + 2 Reference U-235 wt.% Cylinders Three 1S cylinders Fill Height = 26.67 cm 100-wt.% (306 gU/ cylinder) 0.82170 Table 6.4.5-5 Cylinder Spacing = 0.01 cm 5-inch pipe Seven 1S cylinders 20-wt.% (307 gU/ cylinder) H/U-235 = 600 0.81423 Table 6.4.5-13 VP-55 Table 6.4.5-2. Summary Table of 2S Cylinder Single Package Criticality Evaluation Max. Maximum Bounding keff + 2 Reference U-235 wt.% Cylinders Configuration One 2S cylinder Table 6.4.5-100-wt.% (1497 gU/ cylinder) Fill Height = 45.72 cm 0.79059 10 5-inch pipe Two 2S cylinders 20-wt.% (1502 gU/ cylinder) H/U-235 = 550 0.88226 Table 6.4.5-16 VP-55 6.4.5.1 1S Cylinder, 100-wt.% U-235, Single Package For the 1S cylinder, 100-wt.% U-235, single package analysis, the equivalent of three (3) 1S cylinders were modeled with each 1S cylinder in a separate 5-inch pipe, with a maximum uranium mass of 306 g/pipe. The following variables represent the most reactive 1S cylinder, 100-wt.%

U-235, single package configuration: a maximum of 306 gU/cylinder, a 5-inch pipe partial fill height of 26.67 cm, 5-inch pipe centered in the Versa-Pac inner cavity, and fissile material in the form of UO2F2.

6.4.5.1.1 Most Reactive 5-inch Pipe Configuration In this study, several values of uranium mass and sphere size (i.e. H/U-235 ratio) were examined.

Table 6.4.5-3, Table 6.4.5-4 show for 1S cylinder, 100-wt.% U-235, single package analysis that a cylinder spacing of 0.01 cm and the maximum uranium mass of 306 gU/pipe are the bounding parameters for those variables. In conjunction with a partial pipe fill height of 26.67 cm, the configuration produces a keff + 2 of 0.82170, which is the most reactive 1S cylinder, 100-wt.%

U-235, single package configuration. The most reactive case, VP-55_5IP_1S_100_

6-82

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 HAC_UO2F2_SIN_306_26.67_0.01_in, is highlighted in Table 6.4.5-5. Figure 6.4.5-1, Figure 6.4.5-2, and Figure 6.4.5-3 plot these trends for visual inspection.

Note that additional cases were analyzed for the 5-inch pipe fill height study to evaluate a peak between heights of 25.4 and 31.75 cm. A fill height of 26.67 cm is more reactive than the original limiting fill height of 25.4 cm. This refined fill height was not applied to the sensitivity studies, as there would be no apparent difference in the results that would create a more reactive configuration.

Table 6.4.5-3. Effect of 5-inch Pipe Spacing - 1S, 100-wt.% U-235, Single Package Cylinder Case Spacing keff keff + 2 (cm)

VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_25.4_0.01_in 0.01 0.81939 0.00053 0.82045 VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_25.4_0.25_in 0.25 0.81545 0.00056 0.81657 VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_25.4_0.5_in 0.50 0.80757 0.00051 0.80859 Table 6.4.5-4. Effect of Uranium Mass - 1S, 100-wt.% U-235, Single Package Uranium Case keff keff + 2 Mass (g)

VP-55_5IP_1S_100_HAC_UO2F2_SIN_200_25.4_0.01_in 200 0.7342 0.00051 0.73522 VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_25.4_0.01_in 306 0.81939 0.00053 0.82045 Table 6.4.5-5. Effect of 5-inch Pipe Fill Height - 1S, 100-wt.% U-235, Single Package Fill Height Case keff keff + 2 (cm)

VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_17.78_0.01_in 17.78 0.80199 0.00048 0.80295 VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_25.4_0.01_in 25.4 0.81939 0.00053 0.82045 VP-55_5IP_1S_100_HAC_UO2F2_SINR_26.67_in 26.67 0.82060 0.00055 0.82170 VP-55_5IP_1S_100_HAC_UO2F2_SINR_27.94_in 27.94 0.81960 0.00053 0.82066 VP-55_5IP_1S_100_HAC_UO2F2_SINR_29.21_in 29.21 0.81629 0.00056 0.81741 VP-55_5IP_1S_100_HAC_UO2F2_SINR_30.48_in 30.48 0.81452 0.00046 0.81544 VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_31.75_0.01_in 31.75 0.81251 0.00057 0.81365 6-83

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of 5-inch Pipe Spacing on keff 0.835 0.83 0.825 0.82 k-eff + 2 0.815 0.81 0.805 0.8 0.795 0 0.1 0.2 0.3 0.4 0.5 0.6 Cylinder Spacing (cm)

Figure 6.4.5-1. Effect of 5-inch Pipe Spacing - 1S, 100-wt.% U-235, Single Package Effect of Uranium Mass on keff 0.84 0.82 0.8 k-eff + 2 0.78 0.76 0.74 0.72 0.7 150 200 250 300 350 Uranium Mass (g)

Figure 6.4.5-2. Effect of Uranium Mass - 1S, 100-wt.% U-235, Single Package 6-84

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Fill Height on keff 0.83 0.825 0.82 0.815 k-eff + 2 0.81 0.805 0.8 0.795 0.79 15 17.5 20 22.5 25 27.5 30 32.5 35 Cylinder Fill Height (cm)

Figure 6.4.5-3. Effect of 5-inch Pipe Fill Height - 1S, 100-wt.% U-235, Single Package 6.4.5.1.2 Cylinder Positioning Sensitivity Study This study examines the sensitivity of the 1S cylinder, 100-wt.% U-235, single package evaluation to different cylinder positions inside the Versa-Pac, as described in Section 6.3.4.5.2. As shown in Table 6.4.5-6, modeling the 1S cylinder group in the center of the inner cavity produces the bounding cylinder position, with keff + 2 equivalent to 0.82170.

Table 6.4.5-6. Effect of Cylinder Position - 1S, 100-wt.% U-235, Single Package Case Position keff keff + 2 VP-55_5IP_1S_100_HAC_UO2F2_SINR_26.67_in Centered 0.82060 0.00055 0.82170 VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_26.67_0.01_POS_1_in +X 0.81954 0.00049 0.82052 VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_26.67_0.01_POS_2_in +Z 0.82032 0.00058 0.82148 VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_26.67_0.01_POS_3_in -Z 0.82021 0.00051 0.82123 6-85

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.5.1.3 UF6 Fissile Solution Sensitivity Study As shown in Table 6.4.5-7 and Figure 6.4.5-4, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly. Therefore, UO2F2 is the bounding fissile configuration for 1S cylinders with 100-wt.% U-235 enrichment in the single package evaluation.

Although a refinement was done with the Fill Height study in Section 6.4.5.1.1, the increase in reactivity was relatively small. Thus, based on the small relative difference and the trend of other UF6 analyses in this calculation note, the effect of modeling the uranium as UF6 instead of UO2F2 still results in a reduction of reactivity. Therefore, the UF6 cases were not reanalyzed with the revised most reactive fill height of 26.67 cm.

Table 6.4.5-7. Effect of UF6 - 1S, 100-wt.% U-235, Single Package Cylinder Case Spacing keff keff + 2 (cm)

Uranyl Fluoride (UO2F2)

VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_25.4_0.01_in 0.01 0.81939 0.00053 0.82045 VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_25.4_0.25_in 0.25 0.81545 0.00056 0.81657 VP-55_5IP_1S_100_HAC_UO2F2_SIN_306_25.4_0.5_in 0.50 0.80757 0.00051 0.80859 Uranium Hexafluoride (UF6)

VP-55_5IP_1S_100_HAC_UF6_SIN_306_25.4_0.01_in 0.01 0.81675 0.00047 0.81769 VP-55_5IP_1S_100_HAC_UF6_SIN_306_25.4_0.25_in 0.25 0.80987 0.00056 0.81099 VP-55_5IP_1S_100_HAC_UF6_SIN_306_25.4_0.5_in 0.50 0.80437 0.00053 0.80543 Effect of UF6 Fissile Solution on keff 0.835 0.83 0.825 0.82 k-eff + 2 0.815 UO2F2 0.81 UF6 0.805 0.8 0.795 0.00 0.10 0.20 0.30 0.40 0.50 Cylinder Spacing (cm)

Figure 6.4.5-4. Effect of UF6 Fissile Solution - 1S, 100-wt.% U-235, Single Package 6-86

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.5.2 2S Cylinder, 100-wt.% U-235, Single Package For the 2S cylinder, 100-wt.% U-235, single package analysis, one (1) 2S cylinder in a 5-inch pipe was modeled, with a maximum uranium mass of 1497 g/cylinder. The following variables represent the most reactive 2S cylinder, 100-wt.% U-235, single package configuration: a maximum uranium mass of 1497 gU/cylinder, a 5-inch pipe partial fill height of 45.72 cm, a 5-inch pipe position against the top (+z) surface of the Versa-Pac inner cavity, and fissile material in the form of UO2F2.

6.4.5.2.1 Most Reactive Cylinder Configuration In this study, several values of uranium mass, cylinder fill height, and cylinder spacing were evaluated to determine the most reactive configuration. Table 6.4.5-8 and Table 6.4.5-9 show for 2S cylinder, 100-wt.% U-235, single package analysis that a partial fill height of 45.72 cm and the maximum uranium mass of 1497 gU/cylinder are the bounding cylinder configuration, with keff + 2 of 0.78917. This case, VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_45.72_in, is highlighted in the two tables. Figure 6.4.5-5 and Figure 6.4.5-6 plot these trends for visual inspection.

Table 6.4.5-8. Effect of Fill Height - 2S, 100-wt.% U-235, Single Package Cylinder Case Spacing keff keff + 2 (cm)

VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_12.7_in 12.70 0.63806 0.00056 0.63918 VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_25.4_in 25.40 0.75258 0.00052 0.75362 VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_38.1_in 38.10 0.78404 0.00056 0.78516 VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_45.72_in 45.72 0.78807 0.00055 0.78917 VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_53.975_in 53.98 0.78738 0.00054 0.78846 Table 6.4.5-9. Effect of Uranium Mass - 2S, 100-wt.% U-235, Single Package Uranium Case Mass per keff keff + 2 Cylinder (g)

VP-55_2S_100_NCT_UO2F2_SIN_500_20.003_in 500 0.60721 0.00054 0.60829 VP-55_2S_100_NCT_UO2F2_SIN_750_20.003_in 750 0.61877 0.0005 0.61977 VP-55_2S_100_NCT_UO2F2_SIN_1000_20.003_in 1000 0.62203 0.00055 0.62313 VP-55_2S_100_NCT_UO2F2_SIN_1250_20.003_in 1250 0.62293 0.00055 0.62403 VP-55_2S_100_NCT_UO2F2_SIN_1497_20.003_in 1497 0.62149 0.00051 0.62251 6-87

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Fill Height on keff + 2 0.82 0.8 0.78 0.76 0.74 k-eff + 2 0.72 0.7 0.68 0.66 0.64 0.62 5 15 25 35 45 55 65 H/U-235 Figure 6.4.5-5. Effect of Cylinder Fill Height - 2S, 100-wt.% U-235, Single Package Effect of Uranium Mass on keff + 2 0.795 0.79 0.785 0.78 k-eff + 2 0.775 0.77 0.765 0.76 0.755 0.75 800 900 1000 1100 1200 1300 1400 1500 1600 Uranium Mass (g)

Figure 6.4.5-6. Effect of Uranium Mass - 2S, 100-wt.% U-235, Single Package 6-88

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.5.2.2 Cylinder Positioning Sensitivity Study As shown in Table 6.4.5-10, modeling the 100-wt.% U-235, single package, 2S cylinder group in the top of the inner cavity produces the bounding cylinder position, with keff + 2 equivalent to 0.79059.

Table 6.4.5-10. Effect of Cylinder Positioning - 2S, 100-wt.% U-235, Single Package EALF Case Position keff keff + 2 (eV)

VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_45.72_in Centered 0.78807 0.00055 0.78917 1.31E-01 VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_45.72_POS_1_in +X 0.78231 0.00054 0.78339 1.34E-01 VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_45.72_POS_2_in +Z 0.78943 0.00058 0.79059 1.32E-01 VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_45.72_POS_3_in -Z 0.78922 0.00054 0.79030 1.31E-01 6.4.5.2.3 UF6 Fissile Solution Sensitivity Study As shown in Table 6.4.5-11 and Figure 6.4.5-7, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly. Therefore, UO2F2 is the bounding fissile configuration for 2S cylinders with 100-wt.% U-235 enrichment in the single package evaluation.

Table 6.4.5-11. Effect of UF6 - 2S, 100-wt.% U-235, Single Package Fill Height EALF Case keff keff + 2 (cm) (eV)

Uranyl Fluoride (UO2F2)

VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_12.7_in 12.70 0.63806 0.00056 0.63918 1.17E+00 VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_25.4_in 25.40 0.75258 0.00052 0.75362 3.02E-01 VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_38.1_in 38.10 0.78404 0.00056 0.78516 1.65E-01 VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_45.72_in 45.72 0.78807 0.00055 0.78917 1.31E-01 VP-55_5IP_2S_100_HAC_UO2F2_SIN_1497_53.975_in 53.98 0.78738 0.00054 0.78846 1.10E-01 Uranium Hexafluoride (UF6)

VP-55_5IP_2S_100_HAC_UF6_SIN_1497_12.7_in 12.70 0.59664 0.00047 0.59758 1.40E+00 VP-55_5IP_2S_100_HAC_UF6_SIN_1497_25.4_in 25.40 0.73014 0.00053 0.7312 3.25E-01 VP-55_5IP_2S_100_HAC_UF6_SIN_1497_38.1_in 38.10 0.76982 0.00058 0.77098 1.72E-01 VP-55_5IP_2S_100_HAC_UF6_SIN_1497_45.72_in 45.72 0.77662 0.00055 0.77772 1.35E-01 VP-55_5IP_2S_100_HAC_UF6_SIN_1497_53.975_in 53.98 0.77548 0.0005 0.77648 1.12E-01 6-89

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of UF6 Fissile Solution on keff + 2 0.81 0.77 0.73 k-eff + 2 0.69 UO2F2 0.65 UF6 0.61 0.57 10.00 20.00 30.00 40.00 50.00 Fill Height (cm)

Figure 6.4.5-7. Effect of UF6 Fissile Solution - 2S, 100-wt.% U-235, Single Package 6-90

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.5.3 1S Cylinder, 20-wt.% U-235, Single Package For the 20-wt.% U-235 1S cylinder analysis, the equivalent of seven (7) 1S cylinders were modeled in an optimally moderated sphere with a maximum uranium mass of 307 g/cylinder. The following variables represent the most reactive 20-wt.% U-235 1S cylinder single package configuration: a maximum uranium mass of 307 gU/cylinder, an H/U-235 of 600, modeling the fissile sphere in the center of the Versa-Pac inner cavity, and fissile material in the form of UO2F2.

6.4.5.3.1 Most Reactive Cylinder Configuration In this study, several values of uranium mass and sphere size (i.e. H/U-235 ratio) were examined.

Table 6.4.5-12 and Table 6.4.5-13 show that the maximum uranium mass of 307 gU/cylinder and H/U-235 equal to 600 is the bounding 20-wt.% U-235 1S cylinder single package configuration, with keff + 2 of 0.81423. It is also the most reactive 20-wt.% U-235 1S cylinder single package configuration. The most reactive case, VP-55_1S_020_HAC_UO2F2_SIN_2149_600_in, is highlighted in the two tables. Figure 6.4.5-8 and Figure 6.4.5-9 plot these trends for visual inspection.

Table 6.4.5-12. Effect of Sphere Size - 1S, 20-wt.% U-235, Single Package Case H/U-235 keff keff + 2 VP-55_1S_020_HAC_UO2F2_SIN_2149_500_in 500 0.81024 0.00051 0.81126 VP-55_1S_020_HAC_UO2F2_SIN_2149_550_in 550 0.81301 0.00057 0.81415 VP-55_1S_020_HAC_UO2F2_SIN_2149_600_in 600 0.81329 0.00047 0.81423 VP-55_1S_020_HAC_UO2F2_SIN_2149_650_in 650 0.81284 0.00052 0.81388 VP-55_1S_020_HAC_UO2F2_SIN_2149_700_in 700 0.81051 0.0006 0.81171 Table 6.4.5-13. Effect of Uranium Mass - 1S, 20-wt.% U-235, Single Package Uranium Case keff keff + 2 Mass (g)

VP-55_1S_020_HAC_UO2F2_SIN_700_600_in 700 0.57853 0.00047 0.57947 VP-55_1S_020_HAC_UO2F2_SIN_1400_600_in 1400 0.72446 0.00051 0.72548 VP-55_1S_020_HAC_UO2F2_SIN_2149_600_in 2149 0.81329 0.00047 0.81423 6-91

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Sphere Radius on keff 0.828 0.823 0.818 k-eff + 2 0.813 0.808 0.803 0.798 450 500 550 600 650 700 750 H/U-235 Figure 6.4.5-8. Effect of Sphere Radius - 1S, 20-wt.% U-235, Single Package Effect of Uranium Mass on keff 0.85 0.8 0.75 k-eff + 2 0.7 0.65 0.6 0.55 500 700 900 1100 1300 1500 1700 1900 2100 2300 Uranium Mass (g)

Figure 6.4.5-9. Effect of Uranium Mass - 1S, 20-wt.% U-235, Single Package 6-92

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.5.3.2 Fissile Sphere Positioning Sensitivity Study This study examines the sensitivity of the 20-wt.% U-235, 1S cylinder single package evaluation to different sphere positions inside the Versa-Pac, as described in Section 6.3.4.5.2. As shown in Table 6.4.5-14, modeling the 1S cylinder fissile sphere in the center of the inner cavity is the bounding sphere position, with keff + 2 equivalent to 0.81423.

Table 6.4.5-14. Effect of Fissile Sphere Position - 1S, 20-wt.% U-235, Single Package Case Position keff keff + 2 VP-55_1S_020_HAC_UO2F2_SIN_2149_600_in Centered 0.81329 0.00047 0.81423 VP-55_1S_020_HAC_UO2F2_SIN_2149_600_POS_1_in +X 0.81065 0.00047 0.81159 VP-55_1S_020_HAC_UO2F2_SIN_2149_600_POS_2_in +Z 0.81116 0.00058 0.81232 VP-55_1S_020_HAC_UO2F2_SIN_2149_600_POS_3_in -Z 0.81105 0.0005 0.81205 6.4.5.3.3 UF6 Fissile Solution Sensitivity Study As shown in Table 6.4.5-15 and Figure 6.4.5-10, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly for the 1S, 20-wt.% U-235, single package evaluation. Therefore, UO2F2 is the bounding fissile configuration for 20-wt.% 1S cylinders in the single package evaluation.

Table 6.4.5-15. Effect of UF6 - 1S, 20-wt.% U-235, Single Package Cylinder Case Spacing keff keff + 2 (cm)

Uranyl Fluoride (UO2F2)

VP-55_1S_020_HAC_UO2F2_SIN_2149_500_in 500 0.81024 0.00051 0.81126 VP-55_1S_020_HAC_UO2F2_SIN_2149_550_in 550 0.81301 0.00057 0.81415 VP-55_1S_020_HAC_UO2F2_SIN_2149_600_in 600 0.81329 0.00047 0.81423 VP-55_1S_020_HAC_UO2F2_SIN_2149_650_in 650 0.81284 0.00052 0.81388 VP-55_1S_020_HAC_UO2F2_SIN_2149_700_in 700 0.81051 0.0006 0.81171 Uranium Hexafluoride (UF6)

VP-55_1S_020_HAC_UF6_SIN_2149_300_in 300 0.76421 0.00052 0.76525 VP-55_1S_020_HAC_UF6_SIN_2149_400_in 400 0.79278 0.0006 0.79398 VP-55_1S_020_HAC_UF6_SIN_2149_500_in 500 0.80437 0.00045 0.80527 VP-55_1S_020_HAC_UF6_SIN_2149_600_in 600 0.80816 0.00049 0.80914 VP-55_1S_020_HAC_UF6_SIN_2149_700_in 700 0.80686 0.00047 0.8078 6-93

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of UF6 Fissile Solution on keff 0.82 0.81 0.8 k-eff + 2 0.79 UO2F2 0.78 UF6 0.77 0.76 250 350 450 550 650 750 850 Cylinder Spacing (cm)

Figure 6.4.5-10. Effect of UF6 - 1S, 20-wt.% U-235, Single Package 6-94

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.5.4 2S Cylinder, 20-wt.% U-235, Single Package For the 20-wt.% U-235 2S cylinder analysis, the equivalent of two (2) 1S cylinders were modeled in an optimally moderated sphere with a maximum uranium mass of 1502 g/cylinder. The following variables represent the most reactive 20-wt.% U-235 2S cylinder single package configuration: a maximum uranium mass of 1502 gU/cylinder, H/U-235 of 550, fissile sphere modeled in the center of the Versa-Pac inner cavity, and fissile material in the form of UO2F2.

6.4.5.4.1 Most Reactive Cylinder Configuration In this study, several values of uranium mass and sphere size (i.e. H/U-235 ratio) were examined.

Table 6.4.5-16 and Table 6.4.5-17 show that the maximum uranium mass of 1502 gU/cylinder and H/U-235 equal to 550 is the bounding 20-wt.% U-235 2S cylinder single package configuration, with keff + 2 of 0.88226. It is also the most reactive 20-wt.% U-235 2S cylinder single package configuration. The most reactive case, VP-55_1S_020_HAC_UO2F2_SIN_

2149_600_in, is highlighted in the two tables. Figure 6.4.5-11 and Figure 6.4.5-12 plot these trends for visual inspection.

Table 6.4.5-16. Effect of Sphere Size - 2S, 20-wt.% U-235, Single Package Case H/U-235 keff keff + 2 VP-55_2S_020_HAC_UO2F2_SIN_3004_450_in 450 0.87663 0.00049 0.87761 VP-55_2S_020_HAC_UO2F2_SIN_3004_500_in 500 0.88059 0.00057 0.88173 VP-55_2S_020_HAC_UO2F2_SIN_3004_550_in 550 0.88132 0.00047 0.88226 VP-55_2S_020_HAC_UO2F2_SIN_3004_600_in 600 0.88095 0.00062 0.88219 VP-55_2S_020_HAC_UO2F2_SIN_3004_650_in 650 0.88013 0.00066 0.88145 VP-55_2S_020_HAC_UO2F2_SIN_3004_700_in 700 0.87600 0.00057 0.87714 Table 6.4.5-17. Effect of Uranium Mass - 2S, 20-wt.% U-235, Single Package Uranium Case keff keff + 2 Mass (g)

VP-55_2S_020_HAC_UO2F2_SIN_1000_550_in 1000 0.65036 0.00046 0.65128 VP-55_2S_020_HAC_UO2F2_SIN_2000_550_in 2000 0.79725 0.00051 0.79827 VP-55_2S_020_HAC_UO2F2_SIN_3004_550_in 3004 0.88132 0.00047 0.88226 6-95

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Sphere Size on keff 0.9 0.895 0.89 0.885 k-eff + 2 0.88 0.875 0.87 0.865 0.86 400 450 500 550 600 650 700 750 H/U-235 Figure 6.4.5-11. Effect of Sphere Size - 2S, 20-wt.% U-235, Single Package Effect of Uranium Mass on keff 0.9 0.85 0.8 k-eff + 2 0.75 0.7 0.65 0.6 500 1000 1500 2000 2500 3000 3500 Uranium Mass (g)

Figure 6.4.5-12. Effect of Uranium Mass - 2S, 20-wt.% U-235, Single Package 6-96

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.5.4.2 Fissile Sphere Positioning Sensitivity Study This study examines the sensitivity of the 20-wt.% U-235 2S cylinder single package evaluation to different sphere positions inside the Versa-Pac. As shown in Table 6.4.5-18, modeling the 2S fissile sphere in the center of the inner cavity produces the bounding sphere position, with keff + 2 equivalent to 0.88226.

Table 6.4.5-18. Effect of Fissile Position on keff - 2S, 20-wt.% U-235, Single Package Case Position keff keff + 2 VP-55_2S_020_HAC_UO2F2_SIN_3004_550_in Centered 0.88132 0.00047 0.88226 VP-55_2S_020_HAC_UO2F2_SIN_3004_550_POS_1_in +X 0.87870 0.00051 0.87972 VP-55_2S_020_HAC_UO2F2_SIN_3004_550_POS_2_in +Z 0.87936 0.00048 0.88032 VP-55_2S_020_HAC_UO2F2_SIN_3004_550_POS_3_in -Z 0.88024 0.00057 0.88138 6.4.5.4.3 UF6 Fissile Solution Sensitivity Study As shown in Table 6.4.5-19 and Figure 6.4.5-13, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly for the 2S, 20-wt.% U-235, single package evaluation. Therefore, UO2F2 is the bounding fissile configuration for the 20-wt.% 2S cylinder single package evaluation.

Table 6.4.5-19. Effect of UF6 on keff - 2S, 20-wt.% U-235, Single Package Case H/U-235 keff keff + 2 Uranyl Fluoride (UO2F2)

VP-55_2S_020_HAC_UO2F2_SIN_3004_450_in 450 0.87663 0.00049 0.87761 VP-55_2S_020_HAC_UO2F2_SIN_3004_500_in 500 0.88059 0.00057 0.88173 VP-55_2S_020_HAC_UO2F2_SIN_3004_550_in 550 0.88132 0.00047 0.88226 VP-55_2S_020_HAC_UO2F2_SIN_3004_600_in 600 0.88095 0.00062 0.88219 VP-55_2S_020_HAC_UO2F2_SIN_3004_650_in 650 0.88013 0.00066 0.88145 Uranium Hexafluoride (UF6)

VP-55_2S_020_HAC_UF6_SIN_3004_400_in 400 0.86557 0.00052 0.86661 VP-55_2S_020_HAC_UF6_SIN_3004_500_in 500 0.87446 0.00047 0.87540 VP-55_2S_020_HAC_UF6_SIN_3004_600_in 600 0.87651 0.00062 0.87775 VP-55_2S_020_HAC_UF6_SIN_3004_700_in 700 0.87225 0.00053 0.87331 VP-55_2S_020_HAC_UF6_SIN_3004_800_in 800 0.86435 0.00048 0.86531 6-97

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of UF6 Fissile Solution on keff 0.895 0.89 0.885 0.88 k-eff + 2 0.875 UO2F2 0.87 UF6 0.865 0.86 0.855 250 350 450 550 650 750 850 Cylinder Spacing (cm)

Figure 6.4.5-13. Effect of UF6 - 2S, 20-wt.% U-235, Single Package 6-98

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.4.6 High-Capacity Basket with Hydrogen-Limited Contents The results of the Single Package evaluation for the HCB with Hydrogen-Limited contents are listed in Table 6.4.6-1, with the results plotted in Figure 6.4.6-1. This study models the HCB with two (2) 5-inch pipes resting against the bottom surface of, and centered in, the inner cavity. Each pipe starts full of UC. The second case models 0.916 VFUC and 1.25 lb (567 g) of HDPE, which is the hydrogen content limit. The following cases reduce the VF of UC and replace it with water.

This series of cases analyzes a full range of moderation and determines the peak in keff. The Single Package evaluation for the HCB configuration demonstrates that there is a large margin to the USL for all cases.

Table 6.4.6-1. HCB Hydrogen-Limited Content Single Package Criticality Evaluation Case VFUC H/235U keff + 2 1 1.000 0 0.58718 2 0.916 1 0.60629 3 0.800 3 0.62178 4 0.600 7 0.64791 5 0.400 16 0.67710 6 0.200 41 0.71098 7 0.180 47 0.71398 8 0.160 54 0.71429 9 0.140 63 0.71524 10 0.120 75 0.71402 11 0.100 93 0.71136 12 0.080 118 0.70274 13 0.060 161 0.68592 14 0.040 246 0.64977 0.72 0.7 0.68 0.66 keff + 2 0.64 0.62 0.6 0.58 0 0.2 0.4 0.6 0.8 1 Volume Fraction Uranium Carbide Figure 6.4.6-1. Single Package Volume Fraction UC vs. keff 6-99

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5 Evaluation of Package Arrays Under Normal Conditions of Transport For the NCT Package Array Evaluation, the VP-55 is modeled with the dimensions specified in Section 6.3.1. The package interiors are dry as the water-spray test would not result in any in-leakage of water for the VP-55. The space between packages is modeled as dry per 10 CFR 71.59(a)(1). The packages are modeled at nominal dimensions and with reduced tolerances. The only damage modeled is a 0.125 in. (0.318 cm) reduction in the packages outer diameter due to damage, as explained in Section 6.3.1. The fissile shapes are modeled as close as possible to each other in the radial and axial directions to maximize cross-talk between fissile regions, similar to the arrangement in Figure 6.3.4-3. The arrays are modeled with full water reflection of 12 in. (30.48 cm) in all three dimensions. The packages are arranged in a hexagonal pitch. The size of the NCT arrays for each content type are as listed in Table 6.5-1 with the 5N = 252 NCT array shown in Figure 6.5-1 and the 5N = 360 NCT array shown in Figure 6.5-2.

Table 6.5-1. NCT Package Array Configurations U-235 Enrichments NCT Array Size Contents (wt.%) (5N)

Standard All enrichments 252 Hydrogen-All enrichments 360 limited 100, 20 252 5-inch Pipe 10, 5 360 5-inch Pipe Hydrogen- All enrichments 360 limited 1S/2S 100, 20 252 HCB 20 360 6-100

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.5-1. Top and Side Views of 5N = 252 NCT Package Array Figure 6.5-2. Top and Side Views of 5N = 360 NCT Package Array 6-101

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.1 Standard Configuration The following cases analyze the VP-55 with standard contents in the NCT package model presented in Section 6.3.1 in a hexagonally pitched 5N array of 252 packages (7x9x4 packages, array 4-3 per Section 6.3.4.1.5), equivalent to a CSI of 1.0. This array configuration was chosen to minimize neutron leakage for a 252-package array in a cuboid shape. No package flooding is modeled but the array is reflected by at least 12 in. (30.48 cm) of full-density water. All fissile material is moderated by unlimited high-density polyethylene. In addition, an HDPE cavity reflector is analyzed.

6.5.1.1 100-wt.% 235U As shown in Table 6.5.1-1, the 235U mass limit of 360 g determined in the HAC package array evaluation in Section 6.6.1.1 has keff less than the USL of 0.9399 for dry and HDPE cavities. Note that, in this table, the Case Index refers to the varying sphere sizes, as they are different between the two configurations. HDPE is bounding of dry by a margin of approximately 0.006. In addition, the curve in Figure 6.5.1-1 shows that the optimally moderated cases are captured. The HDPE volume fraction study examines reduced volume fractions of the HDPE inner cavity reflector. This study starts with the bounding HDPE case in Table 6.5.1-1. As shown in Table 6.5.1-2, reducing the volume fraction of HDPE present in the inner cavity results in significant reductions in keff.

Therefore, an HDPE cavity volume fraction of 1.0 is bounding for 100-wt.% 235U NCT array. The case with a volume fraction of 0.001 differs from the bounding dry cavity case because the bounding sphere size is different between the dry and HDPE reflector configurations. The bounding sphere size for the HDPE reflector is equivalent to the sphere size of Case Index 2 for the dry case, showing good agreement with the 0.001 case in the HDPE volume fraction study.

A heterogeneous study is done to determine which configuration is bounding. As shown in Table 6.5.1-3 and Figure 6.5.1-2, the heterogeneous configuration is bounded by the homogeneous configuration for this enrichment. Figure 6.5.1-3 shows that as the particle size decreases and the system approaches homogeneity, the bounding result approaches the homogeneous results.

The fissile position study examines the sensitivity of the system to the position of the fissile spheres. In the homogeneous study, the fissile spheres were placed as close together axially and radially as possible. This study examines additional positions to verify that the default fissile position is bounding. As shown in Table 6.5.1-4, modeling the fissile spheres as close together as possible is bounding of other possible fissile positions. Therefore, the default fissile position is bounding for the 100-wt.% NCT array.

The final study examines the sensitivity of the system to the height and configuration of packages in an array. The baseline case models a 4x high array and this study examines 3x and 5x high arrays. In addition, varying rows and columns of packages per array height are examined. As shown in Table 6.5.1-5, the 5-5 array is marginally higher than the baseline case 4-3 array, but this increase does meet the criteria of being statistically significant. Therefore, this array configuration is the bounding array for the 100-wt.% enriched NCT package array.

As demonstrated, the 235U mass limit for 100-wt.% enriched contents in the NCT package array is 360 g with a maximum keff + 2 of 0.93467, below the USL of 0.9399.

6-102

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.1-1. Homogeneous Fissile Mass Size - 100-wt.% 235U Standard NCT Array Case keff + 2 Index Dry HDPE 1 0.88042 0.89286 2 0.91417 0.92345 3 0.92180 0.92952 4 0.92656 0.93298 5 0.92521 0.93124 6 0.92127 0.92776 7 0.91330 0.92118 8 0.88727 0.89790 Table 6.5.1-2. HDPE Cavity Volume Fraction - 100-wt.% 235U Standard NCT Array HDPE Volume keff + 2 Fraction 0.001 0.91493 0.01 0.91447 0.1 0.90208 0.5 0.91264 1.0 0.93298 Table 6.5.1-3. Heterogeneous Fissile Mass Size - 100-wt.% 235U Standard NCT Array Pitch keff + 2 for Particle Radii - 360 g235U Ratio 0.003125 cm 0.00625 cm 0.0125 cm 0.025 cm 10.5 0.87551 0.85775 0.82665 0.76650 11.0 0.88524 0.86557 0.83106 0.76509 11.5 0.88921 0.86905 0.83149 0.75982 12.0 0.88957 0.86659 0.82524 0.75031 12.5 0.88438 0.86070 0.81637 0.73758 13.0 0.87764 0.85166 0.80500 0.72206 13.5 0.86635 0.83916 0.78985 0.70473 Table 6.5.1-4. Fissile Mass Position - 100-wt.% 235U, HDPE Cavity, Standard NCT Array Fissile Position keff + 2 All Close 0.93298 Centered Radially 0.93136 Centered Axially 0.92687 All Centered 0.93036 6-103

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.1-5. Array Configuration Study - 100-wt.% 235U Standard NCT Array Array keff + 2 Indexa Three High Four High Five High 1 0.93291 0.93363 0.93369 2 0.93308 0.93332 0.93260 3 0.93343 0.93298b 0.93229 4 0.93406 0.93236 0.93343 5 0.93305 0.93371 0.93467 Note: a See Section 6.3.4.1.5 for the full array sizes.

b This is the baseline case.

0.95 0.94 0.93 0.92 keff + 2 0.91 Dry 0.9 HDPE 0.89 0.88 0.87 0 200 400 600 800 1000 1200 1400 H/U-235 Figure 6.5.1-1. Homogeneous Fissile Shape - 100-wt.% 235U Standard NCT Array 6-104

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.90 0.85 Hom.

keff + 2 0.003125 cm 0.80 0.00625 cm 0.0125 cm 0.75 0.025 cm 0.70 200 400 600 800 1000 1200 1400 H/U-235 Figure 6.5.1-2. Heterogeneous Particle Results - Dry Cavity, 100-wt.% 235U Standard NCT Array 0.95 0.9 0.85 keff + 2 Het.

0.8 Hom.

0.75 0.7 0 0.005 0.01 0.015 0.02 0.025 0.03 Het. Particle Radius (cm)

Figure 6.5.1-3. Bounding Particle Results - Dry Cavity, 100-wt.% 235U Standard NCT Array 6-105

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.943 0.938 keff + 2 0.933 3 High 4 High 5 High 0.928 0.923 0 1 2 3 4 5 6 Array Index Figure 6.5.1-4. Array Configuration Study - HDPE Cavity, 100-wt.% 235U Standard NCT Array 6-106

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.1.2 20-wt.% 235U As shown in Table 6.5.1-6, a 235U mass of 445 g is the bounding fissile mass with keff under the USL of 0.9416 for a dry inner cavity. In addition, the homogeneous fissile study was done for an inner cavity filled with HDPE. As shown in Table 6.5.1-7, an HDPE inner cavity is bounded by a dry inner cavity by a margin of approximately 0.008. The curves in Figure 6.5.1-5 and Figure 6.5.1-6 show that the optimally moderated cases are captured for dry and HDPE reflectors. The HDPE volume fraction study examines reduced volume fractions of the HDPE reflector. This study starts with the bounding HDPE case in Table 6.5.1-7. As shown in Table 6.5.1-8, reducing the volume fraction of HDPE present in the inner cavity results in significant decreases in keff.

Therefore, the dry cavity is bounding for 20-wt.% 235U NCT array. A heterogeneous study is done to determine which fissile configuration is bounding. As shown in Table 6.5.1-9, Figure 6.5.1-7, and Figure 6.5.1-8, a heterogeneous configuration is bounded by the homogeneous configuration for this enrichment. Figure 6.5.1-8, shows that as the particle size decreases and the system approaches homogeneity, the bounding result approaches the homogeneous results.

The second study examines the sensitivity of the system to the position of the fissile spheres. In the homogeneous study, the fissile spheres were placed as close together axially and radially as possible. This study examines additional radial and axial positions to verify that the default fissile position is bounding. As shown in Table 6.5.1-10, modeling the fissile spheres as close together as possible is bounding of other possible fissile positions. Therefore, the default fissile position is bounding for the 20-wt.% NCT array.

The final study examines the sensitivity of the system to the height and configuration of packages in an array. The baseline case models a 4x high array and this study examines 3x and 5x high arrays. In addition, varying rows and columns of packages per array height are examined. As shown in Table 6.5.1-11, the 4x high array of the baseline case is clearly bounding for the 20-wt.% enriched NCT package array.

As demonstrated, the 235U mass limit for 20-wt.% enriched contents in the NCT package array is 445 g with a maximum keff + 2 of 0.94006, below the USL of 0.9416.

Table 6.5.1-6. Homogeneous Fissile Mass Size - Dry Cavity, 20-wt.% 235U Standard NCT Array Fissile keff + 2 for 235U Masses Radius (cm) 425 g 430 g 435 g 440 g 445 g 11.0 0.89360 0.89598 0.89806 0.90035 0.90141 12.0 0.92009 0.92205 0.92549 0.92759 0.93027 12.5 0.92538 0.92892 0.93155 0.93378 0.93685 13.0 0.92821 0.93068 0.93403 0.93672 0.94006 13.5 0.92555 0.92848 0.93176 0.93582 0.93799 14.0 0.92015 0.92343 0.92687 0.93024 0.93382 15.0 0.90039 0.90279 0.90725 0.91089 0.91474 6-107

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.1-7. Homogeneous Fissile Mass Size - HDPE Cavity, 20-wt.% 235U Standard NCT Array Fissile keff + 2 for 235U Masses Radius (cm) 420 g 425 g 430 g 435 g 440 g 445 g 9.5 0.87122 0.87214 0.87298 0.87342 0.87520 0.87619 10.5 0.90295 0.90448 0.90603 0.90825 0.90953 0.91163 11.0 0.91316 0.91446 0.91701 0.91788 0.92018 0.92208 11.5 0.91790 0.92054 0.92213 0.92491 0.92770 0.92990 12.0 0.92033 0.92268 0.92546 0.92758 0.92934 0.93254 12.5 0.91936 0.92102 0.92459 0.92655 0.92969 0.93196 13.0 0.91485 0.91696 0.92054 0.92286 0.92533 0.92743 14.0 0.89730 0.90046 0.90336 0.90703 0.91025 0.91316 Table 6.5.1-8. HDPE Cavity Volume Fraction wt.% 235U Standard NCT Array HDPE Inner keff + 2 Cavity VF 0.001 0.92997 0.01 0.92982 0.1 0.91781 0.5 0.91879 1.0 0.93254 Table 6.5.1-9. Heterogeneous Particle Results 445 g235U wt.% 235U Standard NCT Array Pitch keff + 2 for Particle Radii1 Ratio1 0.005 cm 0.015 cm 0.025 cm 0.035 cm 0.045 cm 6.00 0.89722 0.89545 0.89161 0.88377 0.87792 6.25 0.90978 0.90776 0.90186 0.89298 0.88514 6.50 0.91830 0.91525 0.90841 0.89709 0.88730 6.75 0.92380 0.91907 0.91007 0.89863 0.88762 7.00 0.92569 0.91869 0.90904 0.89604 0.88409 7.25 0.92331 0.91448 0.90380 0.89002 0.87593 7.50 0.91725 0.90757 0.89572 0.88051 0.86740 Note: 1 Modeled pitch = particle radius

• pitch ratio 6-108

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.1-10. Fissile Mass Position wt.% 235U Standard NCT Package Array Fissile Position keff + 2 All Close 0.94006 Centered Radially 0.93708 Centered Axially 0.92300 All Centered 0.92208 Table 6.5.1-11. Array Configuration Study wt.% 235U, Standard NCT Array Array keff + 2 Indexa Three High Four High Five High 1 0.93191 0.93848 0.93405 2 0.93355 0.93922 0.93553 3 0.93486 0.94006b 0.93721 4 0.93442 0.93995 0.93798 5 0.93250 0.93838 0.93562 a

Note: See Section 6.3.4.1.5 for the full array sizes.

b This is the baseline case.

0.95 0.94 0.93 425 g 0.92 keff + 2 430 g 0.91 435 g 0.9 440 g 445 g 0.89 0.88 10 11 12 13 14 15 16 Fissile Sphere Radius (cm)

Figure 6.5.1-5. Homogeneous Fissile Mass - Dry Cavity, 20-wt.% 235U Standard NCT Array 6-109

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.94 0.93 445 g Dry 0.92 420 g keff + 2 0.91 425 g 0.9 430 g 0.89 435 g 0.88 440 g 0.87 445 g 0.86 9 10 11 12 13 14 15 16 Fissile Sphere Radius (cm)

Figure 6.5.1-6. Homogeneous Fissile Mass - HDPE Cavity, 20-wt.% 235U Standard NCT Array 0.95 0.94 0.93 0.92 445g Hom.

keff + 2 0.91 0.005 cm 0.90 0.015 cm 0.89 0.025 cm 0.88 0.035 cm 0.87 0.045 cm 0.86 300 600 900 1200 H/U-235 Figure 6.5.1-7. Heterogeneous Particle - 445 g235U, Dry Cavity, 20-wt.% 235U Standard NCT Array 6-110

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.94 0.93 0.92 keff + 2 0.91 0.9 Het.

0.89 Hom.

0.88 0.87 0.86 0 0.01 0.02 0.03 0.04 0.05 Particle Radius (cm)

Figure 6.5.1-8. Bounding Particle Results - 445 g235U, Dry Cavity, 20-wt.% 235U Standard NCT Array 0.945 0.94 keff + 2 0.935 3 High 4 High 5 High 0.93 0.925 0 1 2 3 4 5 6 Array Index Figure 6.5.1-9. Array Configuration Study - Dry Cavity, 20-wt.% 235U Standard NCT Array 6-111

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.1.3 10-wt.% 235U As shown in Table 6.5.1-12, a 235U mass of 505 g is the bounding fissile mass with keff under the USL of 0.9415 for a dry inner cavity. In addition, the homogeneous fissile study was done for an inner cavity filled with HDPE. As shown in Table 6.5.1-13, an HDPE inner cavity is bounded by a dry inner cavity, by a margin of over 0.01. The curves in Figure 6.5.1-10 and Figure 6.5.1-11 show that the optimally moderated cases are captured. The HDPE volume fraction study examines various volume fractions of the HDPE inner cavity reflector. This study starts with the bounding HDPE case in Table 6.5.1-13. As shown in Table 6.5.1-14, reducing the volume fraction of HDPE present in the inner cavity results in increased in keff. However, the maximum keff increase of 0.93536 for HDPE VF of 0.001 is bounded by the dry cavity with maximum keff of 0.93761. Therefore, the dry cavity is bounding for 10-wt.% 235U NCT array. A heterogeneous study is done to determine which fissile configuration is bounding. As shown in Table 6.5.1-15, Figure 6.5.1-12, and Figure 6.5.1-13, a heterogeneous configuration is bounded by the homogeneous configuration for this enrichment.

The second study examines the sensitivity of the system to the position of the fissile spheres.

The fissile mass sensitivity study placed the spheres as close together axially and radially as possible. This study examines additional radial and axial positions to verify that the sphere position in the fissile mass size studies are bounding. As shown in Table 6.5.1-16, no other fissile position results in a statistically significant increase in keff. Therefore, the default fissile position is bounding for the 10-wt.% NCT array.

The final study examines the sensitivity of the system to the height and arrangement of packages in an array. The baseline case models a 4x high array and this study examines 3x and 5x high arrays. In addition, varying rows and columns of packages per array height are examined. As shown in Table 6.5.1-17, a 4x high array bounds the other array heights and arrangements. The value of keff for the 4-2 array is marginally higher than the baseline 4-3 case, however, this increase is not a statistically significant one. Therefore, the default array is bounding for the 10-wt.% enriched NCT package array.

As demonstrated, the 235U mass limit for 10-wt.% enriched contents in the NCT package array is 505 g with a maximum keff + 2 of 0.93761, below the USL of 0.9415.

Table 6.5.1-12. Homogeneous Fissile Mass Size - Dry Cavity, 10-wt.% 235U Standard NCT Array Fissile keff + 2 for 235U Masses Radius (cm) 490 g 495 g 500 g 505 g 510 g 11.5 0.89567 0.89674 0.89833 0.89950 0.90261 12.5 0.92183 0.92310 0.92605 0.92731 0.92981 13.0 0.92779 0.93053 0.93239 0.93476 0.93691 13.5 0.93055 0.93282 0.93444 0.93747 0.94030 14.0 0.92975 0.93224 0.93532 0.93761 0.94012 14.5 0.92517 0.92838 0.93085 0.93396 0.93634 15.0 0.91737 0.92049 0.92432 0.92700 0.93013 16.0 0.89553 0.89912 0.90218 0.90566 0.90878 6-112

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.1-13. Homogeneous Fissile Mass Size - HDPE Cavity, 10-wt.% 235U Standard NCT Array Fissile keff + 2 for 235U Masses Radius (cm) 485 g 490 g 495 g 500 g 505 g 10.5 0.88062 0.88278 0.88291 0.88371 0.88546 11.5 0.90552 0.90634 0.90971 0.91038 0.91199 12.0 0.91207 0.91462 0.91610 0.91761 0.91982 12.5 0.91513 0.91760 0.91984 0.92026 0.92335 13.0 0.91601 0.91812 0.91988 0.92071 0.92416 13.5 0.91278 0.91443 0.91700 0.91918 0.92157 14.0 0.90757 0.90946 0.91234 0.91418 0.91702 15.0 0.88857 0.89215 0.89506 0.89629 0.90026 Table 6.5.1-14. HDPE Cavity Volume Fraction wt.% 235U, HDPE Cavity, Standard NCT Array HDPE Inner keff + 2 Cavity VF 0.001 0.93536 0.01 0.93508 0.1 0.92407 0.5 0.91493 1.0 0.92416 Table 6.5.1-15. Heterogeneous Particle 505 g235U - Dry Cavity, 10-wt.% 235U Standard NCT Array Pitch keff + 2 for Particle Radii1 Ratio1 0.005 cm 0.015 cm 0.025 cm 0.035 cm 0.045 cm 4.75 0.89554 0.90182 0.90357 0.90406 0.90350 5.00 0.91414 0.91845 0.91950 0.91880 0.91615 5.25 0.92389 0.92778 0.92855 0.92707 0.92273 5.50 0.92864 0.93097 0.93066 0.92831 0.92324 5.75 0.92728 0.92916 0.92689 0.92397 0.91819 6.00 0.92067 0.92204 0.91930 0.91394 0.90780 6.25 0.91003 0.91043 0.90745 0.90122 0.89302 1

Note: Modeled pitch = particle radius

• pitch ratio 6-113

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.1-16. Fissile Mass Position wt.% 235U Standard NCT Package Array Fissile Position keff + 2 All Close 0.93761 Centered Radially 0.93634 Centered Axially 0.92398 All Centered 0.92243 Table 6.5.1-17. Array Configuration Study wt.% 235U, Standard NCT Array Array keff + 2 Indexa Three High Four High Five High 1 0.93066 0.93609 0.93222 2 0.93185 0.93769 0.93374 b

3 0.93245 0.93761 0.93577 4 0.93230 0.93758 0.93564 5 0.93094 0.93671 0.93416 a

Note: See Section 6.3.4.1.5 for the full array sizes.

b This is the baseline case.

0.95 0.94 0.93 490 g keff + 2 0.92 495 g 500 g 0.91 505 g 0.9 510 g 0.89 11 12 13 14 15 16 17 Fissile Sphere Radius (cm)

Figure 6.5.1-10. Homogeneous Fissile Mass Size - Dry Cavity, 10-wt.% 235U Standard NCT Array 6-114

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.94 0.93 505 g Dry 0.92 keff + 2 490 g 0.91 495 g 0.9 500 g 0.89 505 g 0.88 510 g 0.87 10 11 12 13 14 15 16 17 Fissile Sphere Radius (cm)

Figure 6.5.1-11. Homogeneous Fissile Mass Size - HDPE Cavity, 10-wt.% 235U Standard NCT Array 0.95 0.94 0.93 Hom.

0.92 keff + 2 0.005 cm 0.91 0.015 cm 0.025 cm 0.90 0.035 cm 0.89 0.045 cm 0.88 300 500 700 900 1100 1300 H/U-235 Figure 6.5.1-12. Heterogeneous Particle Results - 505 g235U, Dry Cavity, 10-wt.%

Standard NCT Array 6-115

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.937 0.932 keff + 2 0.927 0.922 0.917 0 0.01 0.02 0.03 0.04 0.05 Particle Radius (cm)

Figure 6.5.1-13. Heterogeneous Bounding Particle- 505 g235U, Dry Cavity, 10-wt.% 235U NCT Array 0.945 0.94 keff + 2 0.935 3 High 4 High 5 High 0.93 0.925 0 1 2 3 4 5 6 Array Index Figure 6.5.1-14. Array Configuration Study - Dry Cavity, 10-wt.% 235U NCT Array 6-116

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.1.4 5-wt.% 235U Enrichment Results As shown in Table 6.5.1-18, a 235U mass of 630 g is the bounding fissile mass with keff under the USL of 0.9417, for a homogeneous system. In addition, the homogeneous fissile study was done for an inner cavity filled with HDPE. As shown in Table 6.5.1-19, an HDPE inner cavity is bounded by a dry inner cavity, by a margin of approximately 0.02. The curves in Figure 6.5.1-15 and Figure 6.5.1-16 show that the optimally moderated cases are captured. The HDPE volume fraction study examines various volume fractions of the HDPE inner cavity reflector. This study starts with the bounding HDPE case in Table 6.5.1-19. As shown in Table 6.5.1-20, reducing the volume fraction of HDPE present in the inner cavity results in increased keff . However, the maximum keff increase of 0.93879 for HDPE VF of 0.001 is bounded by the dry cavity with maximum keff of 0.93894.

Therefore, the dry cavity is bounding for 5-wt.% 235U NCT array. As shown in Table 6.5.1-21 and Figure 6.5.1-17, a heterogeneous system modeling 630 g235U results in an increase of keff above the USL and is bounding of homogeneous. Therefore, the fissile mass must be reduced. As shown in Table 6.5.1-22, Figure 6.5.1-18, and Figure 6.5.1-19, a 235U mass of 610 g is the bounding heterogeneous fissile mass below the USL.

The second study examines the sensitivity of the system to the position of the fissile shapes. The fissile mass sensitivity study placed the shapes as close together axially and radially as possible.

This study examines additional radial and axial positions to verify that the shape position in the fissile mass size studies are bounding. As shown in Table 6.5.1-23, no other fissile position results in a statistically significant increase in keff over the default fissile position. Therefore, the default fissile position is bounding for the 5-wt.% NCT array.

The final study examines the sensitivity of the system to the height and configuration of packages in an array. The baseline case models a 4x high array and this study examines 3x and 5x high arrays. In addition, varying rows and columns of packages per array height are examined. As shown in Table 6.5.1-24, a 4x high array is clearly bounding. The value of keff for the 4-4 array is marginally higher than the baseline 4-3 case, however, this increase is not a statistically significant one. Therefore, the default array is bounding for the 5-wt.% enriched NCT package array.

As demonstrated, the 235U mass limit for 5-wt.% enriched contents in the NCT package array is 610 g with a maximum keff + 2 of 0.93709, below the USL of 0.9417.

Table 6.5.1-18. Homogeneous Fissile Mass - Dry Cavity, 5-wt.% 235U Standard NCT Array Fissile keff + 2 for 235U Masses Radius (cm) 620 g 625 g 630 g 635 g 640 g 13.0 0.91523 0.91539 0.91601 0.91745 0.91798 13.5 0.92543 0.92623 0.92707 0.92845 0.93045 14.0 0.93209 0.93332 0.93469 0.93597 0.93731 14.5 0.93384 0.93652 0.93894 0.93926 0.94160 15.0 0.93460 0.93626 0.93827 0.94011 0.94119 15.5 0.93053 0.93360 0.93491 0.93804 0.93767 16.0 0.92551 0.92766 0.92958 0.93155 0.93360 17.0 0.90578 0.90876 0.91153 0.91411 0.91566 6-117

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.1-19. Homogeneous Fissile Mass - HDPE Cavity, 5-wt.% 235U Standard NCT Array Fissile keff + 2 for 235U Masses Radius (cm) 620 g 625 g 630 g 635 g 640 g 12.0 0.88499 0.88589 0.88628 0.88882 0.88795 12.5 0.89709 0.89822 0.89903 0.89987 0.89998 13.0 0.90443 0.90638 0.90755 0.90785 0.90886 13.5 0.91018 0.91007 0.91075 0.91195 0.91467 14.0 0.91097 0.91154 0.91348 0.91511 0.91620 14.5 0.90946 0.91196 0.91394 0.91442 0.91533 15.0 0.90651 0.90811 0.91081 0.91173 0.91369 16.0 0.89396 0.89583 0.89888 0.90026 0.90179 Table 6.5.1-20. HDPE Cavity Volume Fraction wt.% 235U Standard NCT Array HDPE Volume keff + 2 Fraction 0.001 0.93879 0.01 0.93821 0.1 0.92818 0.5 0.91281 1.0 0.91394 Table 6.5.1-21. Heterogeneous Particle Results 630 g235U wt.% 235U Standard NCT Array Pitch keff + 2 for Particle Radii1 Ratio1 0.0125 cm 0.025 cm 0.050 cm 0.075 cm 0.100 cm 3.75 0.89961 0.90582 0.91305 0.91487 0.91495 4.00 0.92314 0.92915 0.93464 0.93524 0.93370 4.25 0.93562 0.93997 0.94461 0.94278 0.93932 4.50 0.93689 0.94165 0.94480 0.94086 0.93578 4.75 0.92946 0.93500 0.93545 0.93004 0.92316 5.00 0.91693 0.91984 0.91882 0.91151 0.90280 1

Note: Modeled pitch = particle radius

• pitch ratio 6-118

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.1-22. Heterogeneous Particle Results 610 g235U wt.% 235U Standard NCT Array Pitch keff + 2 for Particle Radii1 Ratio1 0.0125 cm 0.025 cm 0.05 cm 0.075 cm 0.100 cm 3.75 0.89091 0.89671 0.90349 0.90602 0.90509 4.00 0.91521 0.92076 0.92532 0.92745 0.92488 4.25 0.92694 0.93278 0.93709 0.93540 0.93139 4.50 0.92885 0.93445 0.93703 0.93357 0.92774 4.75 0.92395 0.92716 0.92773 0.92379 0.91486 5.00 0.91003 0.91415 0.91183 0.90570 0.89639 Note: 1 Modeled pitch = particle radius

• pitch ratio Table 6.5.1-23. Fissile Mass Position wt.% 235U Standard NCT Array Fissile Position keff + 2 All Close 0.93709 Centered Radially 0.93394 Centered Axially 0.91867 All Centered 0.91582 Table 6.5.1-24. Array Configuration Study wt.% 235U Standard NCT Array Array keff + 2 Indexa Three High Four High Five High 1 0.92920 0.93444 0.93048 2 0.93140 0.93485 0.93250 b

3 0.93141 0.93709 0.93514 4 0.93235 0.93807 0.93449 5 0.93027 0.93566 0.93450 a

Note: See Section 6.3.4.1.5 for the full array sizes.

b This is the baseline case.

6-119

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.94 0.93 620 g keff + 2 625 g 0.92 630 g 635 g 0.91 640 g 0.9 12 13 14 15 16 17 18 Fissile Sphere Radius (cm)

Figure 6.5.1-15. Homogeneous Fissile Mass- 630 g235U, Dry Cavity, 5-wt.% 235U Standard NCT Array 0.95 0.94 0.93 630 g Dry 0.92 keff + 2 620 g 0.91 625 g 630 g 0.9 635 g 0.89 640 g 0.88 11 12 13 14 15 16 17 18 Fissile Sphere Radius (cm)

Figure 6.5.1-16. Homogeneous Fissile Mass- 630 g235U, HDPE Cavity, 5-wt.% 235U Standard NCT Array 6-120

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.94 0.93 Hom. Dry keff + 2 0.0125 cm 0.92 0.025 cm 0.91 0.05 cm 0.075 cm 0.9 0.1 cm 0.89 300 500 700 900 1100 H/U-235 Figure 6.5.1-17. Heterogeneous Particle Results - 630 g235U, Dry Cavity, 5-wt.% Standard NCT Array 0.95 0.94 0.93 630g Hom.

Dry 0.92 keff + 2 0.0125 cm 0.91 0.025 cm 0.9 0.05 cm 0.075 cm 0.89 0.1 cm 0.88 300 500 700 900 1100 H/U-235 Figure 6.5.1-18. Heterogeneous Particle Results - 610 g235U, Dry Cavity, 5-wt.% Standard NCT Array 6-121

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.943 0.938 keff + 2 0.933 0.928 0.923 0 0.02 0.04 0.06 0.08 0.1 0.12 Het. Particle Radius (cm)

Figure 6.5.1-19. Bounding Particle Results - 610 g235U, 5-wt.% 235U Standard NCT Array 0.943 0.938 keff + 2 0.933 3 High 4 High 5 High 0.928 0.923 0 1 2 3 4 5 6 Array Index Figure 6.5.1-20. Array Configuration Study wt.% 235U Standard NCT Array 6-122

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.1.5 1.25-wt.% 235U Enrichment As shown in Table 6.5.1-25, a 235U mass of 2000 g, which is derived from the 350 lb (160 kg) maximum payload of the VP-55, is subcritical and below the USL of 0.9423 for a dry cavity and HDPE cavity in the homogeneous configuration. In addition, the dry cavity is bounding of the HDPE cavity for 1.25-wt.%. The curve in Figure 6.5.1-21 shows that the optimally moderated cases are captured. The HDPE volume fraction study examines various volume fractions of the HDPE inner cavity reflector. This study starts with the bounding HDPE case in Table 6.5.1-25.

As shown in Table 6.5.1-26, reducing the volume fraction of HDPE present in the inner cavity results in a significant increase in keff, but is still bounded by the dry cavity. A heterogeneous study is done to determine which configuration is bounding. As shown in Table 6.5.1-27, a heterogeneous configuration modeling 2000 g235U results in an increase of keff above the USL.

Therefore, the fissile mass must be reduced. As shown in Table 6.5.1-28, Figure 6.5.1-23, and Figure 6.5.1-24, a 235U mass of 1650 g is the bounding heterogeneous fissile mass below the USL. Therefore, the heterogeneous configuration bounds the homogeneous configuration for this enrichment.

The second study examines the sensitivity of the system to the position of the fissile shapes. The fissile mass sensitivity study placed the shapes as close together axially and radially as possible.

This study examines additional radial and axial positions to verify that the shape position in the fissile mass size studies are bounding. As shown in Table 6.5.1-29, no other fissile position results in a statistically significant increase in keff over the default fissile position. Therefore, the default fissile position is bounding for the 1.25-wt.% NCT array.

The final study examines the sensitivity of the system to the height and configuration of packages in an array. The baseline case models a 4x high array and this study examines 3x and 5x high arrays. In addition, varying rows and columns of packages per array height are examined. As shown in Table 6.5.1-30, a 4x high packages array is clearly bounding. The value of keff for the 4-4 array is marginally higher than the baseline 4-3 array case, however, this increase is not a statistically significant one. Therefore, the default array is bounding for the 1.25-wt.% enriched NCT package array.

As demonstrated, the 235U mass limit for 1.25-wt.% enriched contents in the NCT package array is 1650 g with a maximum keff + 2 of 0.93844, below the USL of 0.9423.

Table 6.5.1-25. Homogeneous Fissile Mass Size - 1.25-wt.% 235U Standard NCT Array Fissile Cylinder keff + 2 Height (cm) 2000 g235U Dry Cavity 2000 g235U HDPE Cavity 0.001 0.87463 0.83951 5.0 0.89769 0.86104 10.0 0.90617 0.87038 15.0 0.90667 0.87317 20.0 0.90098 0.87019 25.0 0.89394 0.86475 1

Note: Fissile shape is a cylindrical section with two hemispherical end caps, with the radius of the shape equal to the VP inner cavity radius.

6-123

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.1-26. HDPE Cavity Volume Fraction - 1.25-wt.% 235U Standard NCT Array HDPE Volume keff + 2 Fraction 0.001 0.90618 0.01 0.90727 0.1 0.90402 0.5 0.88533 1.0 0.87317 Table 6.5.1-27. Heterogeneous Particle Results 2000 g235U - 1.25-wt.% 235U Standard NCT Array Pitch keff + 2 for Particle Radii1 at 2000 g235U Ratio1 0.20 cm 0.30 cm 0.35 cm 0.40 cm 0.50 cm 2.50 0.93260 0.94338 0.94682 0.94905 0.95143 2.55 0.94148 0.94953 0.95372 0.95537 0.95728 2.60 0.94727 0.95538 0.95864 0.95966 0.96059 2.65 0.95328 0.95979 0.96231 0.96208 0.96190 2.70 0.95626 0.96172 0.96411 0.96309 0.96212 2.75 0.95730 0.96265 0.96499 0.96362 0.96110 2.78 0.95822 0.96274 0.96437 0.96280 0.96105 1

Note: Modeled pitch = particle radius

• pitch ratio Table 6.5.1-28. Heterogeneous Particle Results 1650 g235U - 1.25-wt.% 235U Standard NCT Array Pitch keff + 2 for Particle Radii1 at 1650 g235U Ratio1 0.20 cm 0.30 cm 0.35 cm 0.40 cm 0.50 cm 2.65 0.92386 0.93310 0.93484 0.93399 0.93276 2.70 0.92849 0.93471 0.93604 0.93533 0.93343 2.75 0.93068 0.93741 0.93823 0.93726 0.93259 2.80 0.93287 0.93814 0.93844 0.93670 0.93080 2.85 0.93302 0.93805 0.93768 0.93513 0.92955 2.90 0.93201 0.93523 0.93366 0.93261 0.92431 2.97 0.93003 0.93134 0.92937 0.92680 0.91744 1

Note: Modeled pitch = particle radius

• pitch ratio 6-124

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.1-29. Fissile Mass Position - 1.25-wt.% 235U Standard NCT Array Fissile Position keff + 2 All Close 0.93844 Centered Radially 0.93757 Centered Axially 0.92924 All Centered 0.92945 Table 6.5.1-30. Array Configuration Study - 1.25-wt.% 235U Standard NCT Array Array keff + 2 Indexa Three High Four High Five High 1 0.93258 0.93703 0.93421 2 0.93400 0.93747 0.93590 b

3 0.93409 0.93844 0.93642 4 0.93373 0.93863 0.93745 5 0.93261 0.93695 0.93589 a

Note: See Section 6.3.4.1.5 for the full array sizes.

b This is the baseline case.

0.92 0.91 0.9 0.89 keff + 2 0.88 0.87 Dry 0.86 Poly 0.85 0.84 0.83 0 5 10 15 20 25 30 Fissile Cylindrical Section Height (cm)

Figure 6.5.1-21. Homogeneous Fissile Mass Size - 1.25-wt.% 235U Standard NCT Array 6-125

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.97 0.96 0.95 0.94 2000g Hom.

0.93 keff + 2 0.2 cm 0.92 0.3 cm 0.91 0.35 cm 0.9 0.4 cm 0.89 0.5 cm 0.88 0.87 300 400 500 600 700 800 900 H/U-235 Figure 6.5.1-22. Heterogeneous Particle Results - 2000 g235U, Dry Cavity, Standard NCT Array 0.95 0.94 0.93 2000g Hom.

0.92 keff + 2 0.2 cm 0.91 0.3 cm 0.9 0.35 cm 0.89 0.4 cm 0.88 0.5 cm 0.87 300 400 500 600 700 800 900 H/U-235 Figure 6.5.1-23. Heterogeneous Particle - 1650 g235U, Dry Cavity, 1.25-wt.% Standard NCT Array 6-126

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.945 0.94 keff + 2 0.935 0.93 0.925 0.1 0.2 0.3 0.4 0.5 0.6 Het. Particle Radius (cm)

Figure 6.5.1-24. Bounding Particle Results - 1650 g235U, Dry Cavity, 1.25-wt.% Standard NCT Array 0.945 0.94 keff + 2 0.935 3 High 4 High 5 High 0.93 0.925 0 1 2 3 4 5 6 Array Index Figure 6.5.1-25. Array Configuration Study - 1.25-wt.% 235U Standard NCT Array 6-127

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.2 Hydrogen-Limited Contents Including TRISO Fuels The base study analyzes a fissile sphere with the maximum quantity of uranium and with increasing HDPE up to the maximum quantity of 1 lb. An additional study considering the effect of a graphite moderating material is provided, as graphite is permitted both in uranium compounds (e.g. uranium carbide) and otherwise bound to the uranium material (e.g. TRISO fuel compacts).

6.5.2.1 100-wt.% 235U 6.5.2.1.1 Fissile Sphere Size Variation The results for the NCT package array evaluation are shown in Table 6.5.2-1 and Figure 6.5.2-1.

Because there is no water inleakage into the package during NCT, the maximum quantity of hydrogenous moderator is limited to 1 lb HDPE. For each analyzed 235U mass, the sphere size is increased as HDPE is added to the sphere up to the limit of 1 lb (454 g). Beyond this point, the sphere size is increased with the additional volume modeled as void, reducing the density of the uranium and HDPE materials in the fissile sphere. Increasing the sphere size without the addition of material increases neutron leakage from the fissile sphere resulting in a significant decrease in keff. This effect is visualized in Figure 6.5.2-3 by the steep drop beyond the peak value in each 235 U curve. Note that in Table 6.5.2-4, the radial dimensions of each 235U mass analyzed are slightly different due to the increasing volume of uranium, so the Sphere Size label is a case numbering, not a dimension. For a 5N array of packages under NCT, the NCT package array evaluation shows that there is significant margin between the maximum value of keff and the USL.

Table 6.5.2-1. 100-wt.% 235U Hydrogen-Limited Content NCT Array Results Sphere HDPE keff + 2 Size Mass (g) 300 g 400 g 515 g 600 g 700 g 1 150 0.19892 0.21725 0.23572 0.24838 0.26192 2 300 0.28504 0.30102 0.31527 0.32583 0.33610 3 454 0.36120 0.37601 0.38973 0.39906 0.40902 4 454 0.31169 0.32664 0.34086 0.34962 0.36037 5 454 0.27043 0.28621 0.30028 0.30914 0.31920 6 454 0.23591 0.25185 0.26660 0.27512 0.28466 7 454 0.20821 0.22391 0.23761 0.24696 0.25707 6-128

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.45 0.4 0.35 300 g keff + 2 0.3 400 g 515 g 0.25 600 g 0.2 700 g 0.15 3 3.5 4 4.5 5 5.5 6 Fissile Sphere Radius (cm)

Figure 6.5.2-1. 100-wt.% 235U Hydrogen-Limited Content NCT Array Results 6.5.2.1.2 Non-Hydrogenous Moderator Study To consider the moderating effect of carbon in a uranium compound or graphite mixed with the uranium (e.g. uranium carbide or TRISO compacts), this additional study models the peak 235U mass of 515 g as uranium metal with 1 lb HDPE and an increasing quantity of graphite. This study is done in three phases: (1) a sphere of material increasing to the cavity wall, (2) two hemispherical end caps on a cylinder with a radius equal to the package cavity and increasing height, and (3) a final case of a cylinder filling the entire cavity. The results for the 100-wt.% NCT package array evaluation with graphite moderator are shown in Table 6.5.2-2 and Figure 6.5.2-2.

The plot in Figure 6.5.2-2 also shows a plot of the heterogeneous study results against the homogeneous system results. The results of this additional study show that the addition of a graphite moderator does result in an increase in keff from the HDPE-only cases, but there is still significant margin (~0.3) to the USL.

Next, this section evaluates a heterogeneous array of spherical uranium particles suspended in a homogeneous mixture of graphite and 1 lb HDPE to verify that the homogeneous mixture analyzed in the base NCT package array analysis is bounding. This study is conducted in three phases: (1) increasing the pitch between particles in a cylindrical array with a height-to-diameter ratio of 1 until it radially reaches the cavity wall, (2) increasing only the axial pitch of the particles until nearly the entire cavity is filled by the particle array, and (3) a final case where the entire cavity is filled, but the particles are rearranged to have an equal pitch in all directions.

The results for the NCT package array heterogeneous effects study are shown in Table 6.5.2-3 and Figure 6.5.2-2. As shown, homogeneous is bounding of heterogeneous for 100-wt.%. Also, the peak values for keff remain significantly below both the 100-wt.% HAC array results with a moderating mixture of water and 1 lb HDPE and the USL.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.2-2. Homogeneous Graphite Moderator Results - 100-wt.% 235U Hydrogen-Limited NCT Array Fissile Radius Cylinder Height Fissile Region Volume Study Phase keff + 2 (cm) (cm) (cm3) 15 - 14137 0.32973 16 - 17157 0.36037 1 17 - 20580 0.39471 18 - 24429 0.43120 19.05 - 28958 0.46987 19.05 5 34659 0.51190 19.05 10 40359 0.54518 19.05 15 46060 0.57223 2

19.05 20 51760 0.59041 19.05 25 57461 0.60614 19.05 30 63161 0.61916 3 19.05 68.7388 78369 0.63941 Table 6.5.2-3. Heterogeneous Graphite Moderator - 100-wt.% 235U Hydrogen-Limited NCT Array X/Y Z Fissile Region Study Phase Particle Pitch Particle Pitch Volume keff + 2 (cm) (cm) (cm3) 0.08500 0.08500 318 0.21707 0.09563 0.09563 453 0.27034 0.10838 0.10838 660 0.33445 0.12750 0.12750 1074 0.27743 0.14875 0.14875 1706 0.24236 0.17000 0.17000 2546 0.22683 1

0.21250 0.21250 4974 0.22748 0.25500 0.25500 8594 0.25648 0.29750 0.29750 13648 0.30549 0.34000 0.34000 20372 0.37153 0.38250 0.38250 29006 0.44605 0.43745 0.43745 43390 0.54733 0.43745 0.51000 50585 0.57745 0.43745 0.59500 59016 0.60371 2

0.43745 0.68000 67447 0.62040 0.43745 0.76500 75878 0.63008 3 0.53274 0.53274 78369 0.63022 6-130

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.75 0.65 0.55 keff + 2 0.45 Het.

0.35 Hom.

0.25 0.15 0 20000 40000 60000 80000 Heterogeneous Cylinder Volume (cm3)

Figure 6.5.2-2. 100-wt.% 235U Non-Hydrogenous Moderator NCT Array Study Results 6-131

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.2.2 20-wt.% 235U 6.5.2.2.1 Fissile Sphere Size Variation To cover both 20-wt.% 235U mass limits, the NCT package array is modeled based on the bounding array size (i.e. 360 packages for CSI=0.7) and the target 235U mass is based on the bounding mass determined in the HAC array analysis in Section 6.6.2 (i.e. 635 g235U for CSI=1.0).

The results for the NCT package array evaluation are shown in Table 6.5.2-4 and Figure 6.5.2-3.

The behavior in this study is identical to that experienced with 100-wt.% 235U in Section 6.5.2.1.

Note that in Table 6.5.2-4, the radial dimensions of each 235U mass analyzed are slightly different due to the increasing volume of uranium, so the Sphere Size label is a case numbering, not a dimension. For a 5N array of packages under NCT, the NCT package array evaluation shows that there is significant margin between the maximum value of keff and the USL.

Table 6.5.2-4. 20-wt.% 235U Hydrogen-Limited Content NCT Array Results Sphere HDPE keff + 2 Size Mass (g) 450 g 550 g 635 g 750 g 850 g 1 150 0.19855 0.21226 0.22242 0.23524 0.24503 2 300 0.26748 0.27763 0.28462 0.29530 0.30384 3 454 0.33275 0.34073 0.34747 0.35624 0.36180 4 454 0.29210 0.30086 0.30797 0.31622 0.32344 5 454 0.25747 0.26783 0.27440 0.28372 0.29010 6 454 0.22993 0.24002 0.24684 0.25637 0.26392 7 454 0.20668 0.21696 0.22470 0.23346 0.24212 0.40 0.35 0.30 450 g k-eff + 2s 550 g 0.25 635 g 750 g 0.20 850 g 0.15 4 4.5 5 5.5 6 6.5 7 Fissile Sphere Radius (cm)

Figure 6.5.2-3. 20-wt.% 235U Hydrogen-Limited Content NCT Array Results 6-132

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.2.2.2 Non-Hydrogenous Moderator Study To consider the moderating effect of carbon in a uranium compound or graphite mixed with the uranium (e.g. uranium carbide or TRISO compacts), this additional study models the peak 235U mass of 635 g as uranium metal with 1 lb HDPE and an increasing quantity of graphite. This study is done in three phases like with 100-wt.% 235U. The results for the 20-wt.% NCT package array evaluation with graphite moderator are shown in Table 6.5.2-5 and Figure 6.5.2-4. The plot in Figure 6.5.2-4 also shows the heterogeneous study results against the homogeneous system results. The results of this additional study show that the addition of a graphite moderator does result in an increase in keff from the HDPE-only cases, but there is still significant margin (~0.3) to the USL.

Next, this section evaluates a heterogeneous array of spherical uranium particles suspended in a homogeneous mixture of graphite and 1 lb HDPE to verify that the homogeneous mixture analyzed in the base NCT package array analysis is bounding. This study is conducted in three phases like with 100-wt.%.

The results for the NCT package array heterogeneous effects study are shown in Table 6.5.2-6 and Figure 6.5.2-4. The results show a slight increase in keff for the heterogeneous system versus a homogeneous system, however, it is uncertain if this is a true effect or only due to the approximation of the heterogeneous system modeling. Regardless, the peak values for keff remain significantly below both the HAC array results with a moderating mixture of water and 1 lb HDPE and the USL.

Table 6.5.2-5. Homogeneous Graphite Moderator Results wt.% 235U Hydrogen-Limited NCT Array Fissile Radius Cylinder Height Fissile Region Volume Study Phase keff + 2 (cm) (cm) (cm3) 15 - 14137 0.29995 16 - 17157 0.32669 1 17 - 20580 0.35604 18 - 24429 0.38769 19.05 - 28958 0.42385 19.05 5 34659 0.46360 19.05 10 40359 0.49693 19.05 15 46060 0.52414 2

19.05 20 51760 0.54755 19.05 25 57461 0.56613 19.05 30 63161 0.58051 3 19.05 68.7388 78369 0.61291 6-133

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.2-6. Heterogeneous Graphite Moderator Results wt.% 235U Hydrogen-Limited NCT Array X/Y Z Fissile Region Study Phase Particle Pitch Particle Pitch Volume keff + 2 (cm) (cm) (cm3) 0.08500 0.08500 318 0.21707 0.09563 0.09563 453 0.27034 0.10838 0.10838 660 0.33445 0.12750 0.12750 1074 0.27743 0.14875 0.14875 1706 0.24236 0.17000 0.17000 2546 0.22683 1

0.21250 0.21250 4974 0.22748 0.25500 0.25500 8594 0.25648 0.29750 0.29750 13648 0.30549 0.34000 0.34000 20372 0.37153 0.38250 0.38250 29006 0.44605 0.43745 0.43745 43390 0.54733 0.43745 0.51000 50585 0.57745 0.43745 0.59500 59016 0.60371 2

0.43745 0.68000 67447 0.62040 0.43745 0.76500 75878 0.63008 3 0.53274 0.53274 78369 0.63022 0.75 0.65 0.55 k-eff + 2s 0.45 Het.

0.35 Hom.

0.25 0.15 0 20000 40000 60000 80000 Heterogeneous Cylinder Volume (cm3)

Figure 6.5.2-4. 20-wt.% 235U Non-Hydrogenous Moderator NCT Array Study Results 6-134

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.2.3 10-wt.% 235U 6.5.2.3.1 Fissile Sphere Size Variation The results for the 10-wt.% 235U NCT package array evaluation are shown in Table 6.5.2-7 and Figure 6.5.2-5. The behavior in this study is identical to that experienced with 100-wt.% 235U in Section 6.5.2.1. Note that in Table 6.5.2-7, the radial dimensions of each 235U mass analyzed are slightly different due to the increasing volume of uranium, so the Sphere Size label is a case numbering, not a dimension. For a 5N array of packages under NCT, the 10-wt.% 235U NCT package array evaluation shows that there is significant margin between the maximum value of keff and the USL.

Table 6.5.2-7. 10-wt.% 235U Hydrogen-Limited Content NCT Array Results Sphere HDPE keff + 2 Size Mass (g) 500 g 600 g 685 g 800 g 900 g 1 150 0.19835 0.21064 0.22008 0.23156 0.24061 2 300 0.25445 0.26316 0.27056 0.27961 0.28770 3 454 0.31183 0.31883 0.32459 0.33132 0.33761 4 454 0.27614 0.28425 0.29043 0.29791 0.30459 5 454 0.24628 0.25489 0.26147 0.26968 0.27783 6 454 0.22218 0.23157 0.23828 0.24728 0.25475 7 454 0.20283 0.21239 0.21941 0.22925 0.23658 0.35 0.33 0.31 0.29 500 g keff + 2 0.27 600 g 0.25 685 g 800 g 0.23 900 g 0.21 0.19 4.5 5 5.5 6 6.5 7 7.5 Fissile Sphere Radius (cm)

Figure 6.5.2-5. 10-wt.% 235U Hydrogen-Limited Content NCT Array Results 6-135

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.2.3.2 Non-Hydrogenous Moderator Study To consider the moderating effect of carbon in a uranium compound or graphite mixed with the uranium (e.g. uranium carbide or TRISO compacts), this additional study models the peak 235U mass of 685 g as uranium metal with 1 lb HDPE and an increasing quantity of graphite. This study is done in three phases like with 100-wt.% 235U. The results for the 10-wt.% NCT package array evaluation with graphite moderator are shown in Table 6.5.2-8 and Figure 6.5.2-6. The plot in Figure 6.5.2-6 also shows the heterogeneous study results against the homogeneous system results. The results of this additional study show that the addition of a graphite moderator does result in an increase in keff from the HDPE-only cases, but there is still significant margin (~0.3) to the USL.

Next, this section evaluates a heterogeneous array of spherical uranium particles suspended in a homogeneous mixture of graphite and 1 lb HDPE to verify that the homogeneous mixture analyzed in the base NCT package array analysis is bounding. This study is conducted in three phases like with 100-wt.%.

The results for the NCT package array heterogeneous effects study are shown in Table 6.5.2-9 and Figure 6.5.2-6. The results show an increase in keff for the heterogeneous system versus a homogeneous system. The peak values for keff remain significantly below the HAC array results with a moderating mixture of water and 1 lb HDPE and the USL.

Table 6.5.2-8. Homogeneous Graphite Moderator Results wt.% 235U Hydrogen-Limited NCT Array Fissile Radius Cylinder Height Fissile Region Volume Study Phase keff + 2 (cm) (cm) (cm3) 15 - 14137 0.28278 16 - 17157 0.30470 1 17 - 20580 0.33061 18 - 24429 0.35836 19.05 - 28958 0.39109 19.05 5 34659 0.42491 19.05 10 40359 0.45533 19.05 15 46060 0.48122 2

19.05 20 51760 0.50173 19.05 25 57461 0.52016 19.05 30 63161 0.53608 3 19.05 68.7388 78369 0.56899 6-136

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.2-9. Heterogeneous Graphite Moderator Results wt.% 235U Hydrogen-Limited NCT Array X/Y Z Fissile Region Study Phase Particle Pitch Particle Pitch Volume keff + 2 (cm) (cm) (cm3) 0.08500 0.08500 687 0.27221 0.09010 0.09010 818 0.31723 0.09563 0.09563 978 0.29776 0.10625 0.10625 1341 0.26842 1

0.12750 0.12750 2318 0.23505 0.17000 0.17000 5494 0.22891 0.25500 0.25500 18542 0.33529 0.33788 0.33788 43133 0.52722 0.33788 0.42500 54255 0.57785 2 0.33788 0.51000 65106 0.60895 0.33788 0.61370 78344 0.63240 3 1.63648 1.63648 78369 0.63261 0.75 0.65 0.55 keff + 2 0.45 Het.

0.35 Hom.

0.25 0.15 0 20000 40000 60000 80000 Heterogeneous Cylinder Volume (cm3)

Figure 6.5.2-6. 10-wt.% 235U Non-Hydrogenous Moderator NCT Array Study Results 6-137

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.2.4 5-wt.% 235U 6.5.2.4.1 Fissile Sphere Size Variation The results for the 5-wt.% 235U NCT package array evaluation are shown in Table 6.5.2-10 and Figure 6.5.2-7. The behavior in this study is identical to that experienced with 100-wt.% 235U in Section 6.5.2.1. Note that in Table 6.5.2-10, the radial dimensions of each 235U mass analyzed are slightly different due to the increasing volume of uranium, so the Sphere Size label is a case numbering, not a dimension. For a 5N array of packages under NCT, the 5-wt.% 235U NCT package array evaluation shows that there is significant margin between the maximum value of keff and the USL.

Table 6.5.2-10. 5-wt.% 235U Hydrogen-Limited Content NCT Array Results Sphere HDPE keff + 2 Size Mass (g) 600 g 700 g 800 g 900 g 1000 g 1 150 0.21089 0.22224 0.23222 0.24183 0.25033 2 300 0.24757 0.25727 0.26596 0.27359 0.28097 3 454 0.29142 0.29921 0.30521 0.31165 0.31840 4 454 0.26362 0.27173 0.27889 0.28547 0.29228 5 454 0.24017 0.24909 0.25735 0.26431 0.27179 6 454 0.22172 0.23098 0.23888 0.24747 0.25503 7 454 0.20657 0.21589 0.22508 0.23278 0.24081 0.34 0.32 0.3 600 g 0.28 keff + 2 700 g 0.26 800 g 0.24 900 g 1000 g 0.22 0.2 5.5 6 6.5 7 7.5 8 8.5 9 Fissile Sphere Radius (cm)

Figure 6.5.2-7. 5-wt.% 235U Hydrogen-Limited Content NCT Array Results 6-138

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.2.4.2 Non-Hydrogenous Moderator Study To consider the moderating effect of carbon in a uranium compound or graphite mixed with the uranium (e.g. uranium carbide or TRISO compacts), this additional study models the peak 235U mass of 800 g as uranium metal with 1 lb HDPE and an increasing quantity of graphite. This study is done in three phases like with 100-wt.% 235U. The results for the 5-wt.% NCT package array evaluation with graphite moderator are shown in Table 6.5.2-11 and Figure 6.5.2-8. The plot in Figure 6.5.2-8 also shows the heterogeneous study results against the homogeneous system results. The results of this additional study show that the addition of a graphite moderator does result in an increase in keff from the HDPE-only cases, but there is still significant margin

(~0.3) to the USL.

Next, this section evaluates a heterogeneous array of spherical uranium particles suspended in a homogeneous mixture of graphite and 1 lb HDPE to verify that the homogeneous mixture analyzed in the base NCT package array analysis is bounding. This study is conducted in three phases like with 100-wt.%.

The results for the NCT package array heterogeneous effects study are shown in Table 6.5.2-12 and Figure 6.5.2-8. The results show an increase in keff for the heterogeneous system versus a homogeneous system. The peak values for keff remain significantly below the HAC array results with a moderating mixture of water and 1 lb HDPE and the USL.

Table 6.5.2-11. Homogeneous Graphite Moderator Results wt.% 235U Hydrogen-Limited NCT Array Fissile Radius Cylinder Height Fissile Region Volume Study Phase keff + 2 (cm) (cm) (cm3) 15 - 14137 0.26771 16 - 17157 0.28432 1 17 - 20580 0.30345 18 - 24429 0.32595 19.05 - 28958 0.35154 19.05 5 34659 0.38063 19.05 10 40359 0.40720 19.05 15 46060 0.42945 2

19.05 20 51760 0.44916 19.05 25 57461 0.46605 19.05 30 63161 0.48104 3 19.05 68.7388 78369 0.51471 6-139

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.2-12. Heterogeneous Graphite Moderator Results wt.% 235U Hydrogen-Limited NCT Array X/Y Z Fissile Region Study Phase Particle Pitch Particle Pitch Volume keff + 2 (cm) (cm) (cm3) 0.08500 0.08500 1604 0.28157 0.12750 0.12750 5414 0.23456 1 0.17000 0.17000 12833 0.26879 0.21250 0.21250 25064 0.35562 0.25500 0.25500 43310 0.47768 0.25500 0.29750 50529 0.51395 0.25500 0.34000 57747 0.54293 2

0.25500 0.38250 64965 0.56525 0.25500 0.42500 72184 0.58468 3 0.31074 0.31074 78369 0.59731 0.65 0.60 0.55 0.50 0.45 keff + 2 0.40 Het.

0.35 Hom.

0.30 0.25 0.20 0.15 0 20000 40000 60000 80000 Heterogeneous Cylinder Volume (cm3)

Figure 6.5.2-8. 5-wt.% 235U Non-Hydrogenous Moderator NCT Array Study Results 6-140

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.3 5-inch Pipe Table 6.5.3-1 summarizes the results of the NCT Package Array Evaluation. All of the limiting fill percentages of the 5-inch pipe container resulted from a 100 percent fill, except for U(100), whose most reactive fill was 95 percent. Therefore, it cannot be concluded whether or not optimal moderation was achieved for any NCT Package Array Evaluation. For U(100) and U(20), the U-235 mass limit was determined so as to not surpass the USL for the limiting fill percentage identified. However, for U(10), the maximum keff occurred for 1605 g235U with decreases in keff when increasing or decreasing the fissile mass. This demonstrates that U(10) is volume-limited and that there is no limit on U(10), other than what can physically fit in the 5-inch pipe.

Table 6.5.3-1. Summary of Limiting Cases for NCT Package Array Evaluation Number of U-235 U-235 Fill Case Packages keff + 2 USL Enrichment Mass (g) Percent (5N)

VP-55_5IP_NCT_100WT_4X252_VF095 100 695 252 95 0.93824 0.9391 VP-55_5IP_NCT_20WT_4X252_VF100 20 1215 252 100 0.93784 0.9389 VP-55_5IP_NCT_10WT_4X360_VF100 10 1605 360 100 0.91337 0.9376 The Variation of Fissile Mass study for package arrays under NCT, the second study in this section, shows that the U-235 masses presented in Table 6.5.3-1 are the limit-defining cases, either the most limiting value of keff + 2 under the USL, or the most reactive H/U-235 ratio. The following parameter sensitivity studies confirm that the fill percentage, array configuration, and fissile mass modeled result in the maximum values of keff + 2 possible.

6.5.3.1 Variation of Fill Parameter Study - NCT Package Array For the variation of fill percentage parameter study of a package array under NCT, the limit-defining U-235 masses determined were held constant as the fill percentage of the 5-inch pipe container was varied. This resulted in a variation of the amount of high-density polyethylene (HDPE) moderator, thus a variation of the H/U-235 ratio, to determine which fill percentage would produce the maximum value of keff + 2.

Case VP-55_5IP_NCT_100WT_4X252_VF080 is a case that models the Versa-Pac 55-gallon version (VP-55) with the 5-inch pipe container (5IP) under Normal Conditions of Transport (NCT),

with 100-wt.% U-235 enriched uranium (100WT) in an array that is 4 packages tall with 252 total packages (4X252), in the Variation of Fill parameter study (VF) and with a 5-inch pipe fill percentage of 80% (080).

Table 6.5.3-2 shows the values of keff and for the different fill percentages examined. Note the limit-defining cases are highlighted. Figure 6.5.3-1 plots the results. The results are as follows:

• For 100-wt.% U-235 enriched uranium, a fill of 95% with 695 g of U-235 results in the limiting configuration under the USL with a keff + 2 of 0.93824 and a value of H/U-235 of 311.02.

• For 20-wt.% U-235 enriched uranium, a fill of 100% with 1215 g of U-235 results in the limiting configuration under the USL with a keff + 2 of 0.93784 and a value of H/U-235 of 179.69.

• For 10-wt.% U-235 enriched uranium, a fill of 100% with 1605 g of U-235 results in the limiting configuration under the USL with a keff + 2 of 0.91337 and a value of H/U-235 of 125.31. As the largest keff is with the pipe 100% full and keff + 2 is approximately 0.03 less than the USL, this shows that U(10) is volume-limited in the 5-inch pipe.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.3-2. Fill Percentage Sensitivity of the 5-Inch Pipe Container - NCT Package Array Fill Case H/U-235 keff keff + 2 Percentage 100-wt.% U-235 Enriched Uranium VP-55_5IP_NCT_100WT_4X252_VF080 80 261.64 0.93356 0.00057 0.9347 VP-55_5IP_NCT_100WT_4X252_VF085 85 278.10 0.93515 0.00057 0.93629 VP-55_5IP_NCT_100WT_4X252_VF090 90 294.56 0.9361 0.00052 0.93714 VP-55_5IP_NCT_100WT_4X252_VF095 95 311.02 0.93708 0.00058 0.93824 VP-55_5IP_NCT_100WT_4X252_VF100 100 327.48 0.93706 0.00054 0.93814 20-wt.% U-235 Enriched Uranium VP-55_5IP_NCT_20WT_4X252_VF080 80 142.03 0.90845 0.00051 0.90947 VP-55_5IP_NCT_20WT_4X252_VF085 85 151.44 0.91686 0.00053 0.91792 VP-55_5IP_NCT_20WT_4X252_VF090 90 160.86 0.92543 0.00058 0.92659 VP-55_5IP_NCT_20WT_4X252_VF095 95 170.27 0.93062 0.00057 0.93176 VP-55_5IP_NCT_20WT_4X252_VF100 100 179.69 0.9367 0.00057 0.93784 10-wt.% U-235 Enriched Uranium VP-55_5IP_NCT_10WT_4X360_VF080 80 96.80 0.86483 0.00062 0.86607 VP-55_5IP_NCT_10WT_4X360_VF085 85 103.93 0.87842 0.00054 0.8795 VP-55_5IP_NCT_10WT_4X360_VF090 90 111.05 0.89057 0.00053 0.89163 VP-55_5IP_NCT_10WT_4X360_VF095 95 118.18 0.90096 0.00058 0.90212 VP-55_5IP_NCT_10WT_4X360_VF100 100 125.31 0.91229 0.00054 0.91337 0.95 0.94 0.93 0.92 keff + 2 0.91 100-wt.%

0.9 20-wt.%

0.89 10-wt.%

0.88 0.87 0.86 80 85 90 95 100 Fill Percentage Figure 6.5.3-1. Variation of Fill Sensitivity inch Pipe NCT Package Array 6-142

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.3.2 Variation of Fissile Mass Parameter Study - NCT Package Array In the variation of fissile mass parameter study of a package array under NCT, the limiting fill percentages, as determined in the variation of fill percentage parameter study, were held constant as the H/U-235 ratio was varied, therefore varying the mass of U-235 in the 5-inch pipe container.

This parameter study shows that the fissile mass limit defined, and its corresponding ratio of H/U-235, is limiting under the USL. Case VP-55_5IP_NCT_100WT_4X252_VM655 models the Variation of Fissile Mass (VM) parameter study with 655 g of U-235 (655). Table 6.5.3-3 shows the values of keff and for the different fissile mass amounts examined. Note that the limit-defining cases are highlighted. Figure 6.5.3-2 through Figure 6.5.3-4 plot the trends for visual inspection.

The results are:

• For 100-wt.% U-235 enriched uranium, a U-235 mass limit of 695 g with the 5-inch pipe container 95% full results in the limiting configuration under the USL with a keff + 2 of 0.93824 and a value of H/U-235 of 311.02.

• For 20-wt.% U-235 enriched uranium, a U-235 mass limit of 1215 g with the 5-inch pipe container 100% full results in the limiting configuration under the USL with a keff + 2 of 0.93784 and a value of H/U-235 of 179.69.

• For 10-wt.% U-235 enriched uranium, a U-235 mass limit of 1605 g with the 5-inch pipe container 100% full results in the peak value of keff for any U-235 mass analyzed. The peak case has keff + 2 of 0.91337 with the 5-inch pipe container full and H/U-235 of 125.31. This supports the conclusion that 10-wt.% U-235 is volume limited by the 5-inch pipe.

Table 6.5.3-3. U-235 Mass Sensitivity of the 5-Inch Pipe Container - NCT Package Array Case Mass U-235 (g) H/U-235 keff keff + 2 100-wt.% U-235 Enriched Uranium VP-55_5IP_NCT_100WT_4X252_VM655 655 330.11 0.92464 0.00054 0.92572 VP-55_5IP_NCT_100WT_4X252_VM675 675 320.28 0.93181 0.00056 0.93293 VP-55_5IP_NCT_100WT_4X252_VM695 695 311.02 0.93708 0.00058 0.93824 VP-55_5IP_NCT_100WT_4X252_VM715 715 302.27 0.94172 0.00053 0.94278 VP-55_5IP_NCT_100WT_4X252_VM735 735 294.00 0.94729 0.00055 0.94839 20-wt.% U-235 Enriched Uranium VP-55_5IP_NCT_20WT_4X252_VM1115 1115 196.58 0.92954 0.00058 0.9307 VP-55_5IP_NCT_20WT_4X252_VM1165 1165 187.77 0.93455 0.00059 0.93573 VP-55_5IP_NCT_20WT_4X252_VM1215 1215 179.69 0.9367 0.00057 0.93784 VP-55_5IP_NCT_20WT_4X252_VM1265 1265 172.24 0.9406 0.00052 0.94164 VP-55_5IP_NCT_20WT_4X252_VM1315 1315 165.37 0.94309 0.00057 0.94423 10-wt.% U-235 Enriched Uranium VP-55_5IP_NCT_10WT_4X360_VM1505 1505 134.78 0.91063 0.00052 0.91167 VP-55_5IP_NCT_10WT_4X360_VM1555 1555 129.89 0.91069 0.00053 0.91175 VP-55_5IP_NCT_10WT_4X360_VM1605 1605 125.31 0.91229 0.00054 0.91337 VP-55_5IP_NCT_10WT_4X360_VM1655 1655 121.00 0.91198 0.00058 0.91314 VP-55_5IP_NCT_10WT_4X360_VM1705 1705 116.95 0.91116 0.00051 0.91218 6-143

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.945 0.94 keff + 2 0.935 0.93 0.925 0.92 650 660 670 680 690 700 710 720 730 740 U-235 Mass (g)

Figure 6.5.3-2. Variation of U-235 Mass Sensitivity - U(100) 5-inch Pipe NCT Package Array 0.948 0.944 0.94 keff + 2 0.936 0.932 0.928 1100 1150 1200 1250 1300 1350 U-235 Mass (g)

Figure 6.5.3-3. Variation of U-235 Mass Sensitivity - U(20) 5-inch Pipe NCT Package Array 6-144

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.922 0.917 keff + 2 0.912 0.907 0.902 1450 1500 1550 1600 1650 1700 1750 U-235 Mass (g)

Figure 6.5.3-4. Variation of U-235 Mass Sensitivity - U(10) 5-inch Pipe NCT Package Array 6.5.3.3 Array Configuration Parameter Study - NCT Package Array In the array configuration sensitivity parameter study of a package array under NCT, several different array configurations were examined to verify the CSI-limiting configuration was properly modeled. The two variables modified were the height of the array, in number of packages, and the overall size of the array; that is, the number of packages in the array. Three different package heights3, 4, and 5 packages tallwere modeled with several different array sizes each, maintaining 5N number of packages around 252 for a CSI = 1.0 for U(100) and U(20) and 5N number of packages around 360 for a CSI = 0.7 for U(10).

Table 6.5.3-4 through Table 6.5.3-6 show the values of keff and for the different array configurations examined. Note the limit-defining cases are highlighted in the following array configuration sensitivity tables. Figure 6.5.3-5 through Figure 6.5.3-7 plot the results for visual inspection. As shown, an array configuration with a height of four packages is bounding for all four enrichment levels. For U(100) and U(20), a total of 252 packages resulted in the limiting value of keff + 2 under the USL while maintaining a CSI = 1.0. For U(10), although package array sizes of 4x380 and 5x385 had higher values of keff + 2, those array sizes are unnecessarily conservative in size to derive a CSI = 0.7. Also for U(10), the 5-package tall trend crosses the 4-package tall trend at an array size of approximately 370 packages and larger; the crossover occurs at a point where the array size is unnecessarily conservative to derive a CSI = 0.7. The variables of the problem are set as follows:

• For 100-wt.% U-235 enriched uranium, the 5-inch pipe is 95 percent full and models 695 g of U-235. The H/U-235 for all cases modeled was 311.02.

• For 20-wt.% U-235 enriched uranium, the 5-inch pipe is 100 percent full and models 1215 g of U-235. The H/U-235 for all cases modeled was 179.69.

• For 10-wt.% U-235 enriched uranium, the 5-inch pipe is 100 percent full and models 1605 g of U-235. The H/U-235 for all cases modeled was 125.31.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.3-4. Array Configuration Sensitivity of the 5-Inch Pipe - U(100) NCT Package Array Case Array Height Array Size keff keff + 2 VP-55_5IP_NCT_100WT_3X240_AS 3 240 0.92822 0.00058 0.92938 VP-55_5IP_NCT_100WT_3X255_AS 3 255 0.93154 0.00052 0.93258 VP-55_5IP_NCT_100WT_3X270_AS 3 270 0.93652 0.00055 0.93762 VP-55_5IP_NCT_100WT_4X236_AS 4 236 0.93096 0.00055 0.93206 VP-55_5IP_NCT_100WT_4X252_AS 4 252 0.93708 0.00058 0.93824 VP-55_5IP_NCT_100WT_4X272_AS 4 272 0.94320 0.00056 0.94432 VP-55_5IP_NCT_100WT_5X240_AS 5 240 0.92908 0.00059 0.93026 VP-55_5IP_NCT_100WT_5X260_AS 5 260 0.93401 0.00054 0.93509 VP-55_5IP_NCT_100WT_5X280_AS 5 280 0.94259 0.00064 0.94387 Table 6.5.3-5. Array Configuration Sensitivity of the 5-Inch Pipe - U(20) NCT Package Array Case Array Height Array Size keff keff + 2 VP-55_5IP_NCT_20WT_3X240_AS 3 240 0.92763 0.00051 0.92865 VP-55_5IP_NCT_20WT_3X255_AS 3 255 0.93164 0.00055 0.93274 VP-55_5IP_NCT_20WT_3X270_AS 3 270 0.93533 0.00056 0.93645 VP-55_5IP_NCT_20WT_4X236_AS 4 236 0.93085 0.00054 0.93193 VP-55_5IP_NCT_20WT_4X252_AS 4 252 0.9367 0.00057 0.93784 VP-55_5IP_NCT_20WT_4X272_AS 4 272 0.94388 0.00064 0.94516 VP-55_5IP_NCT_20WT_5X240_AS 5 240 0.92947 0.00057 0.93061 VP-55_5IP_NCT_20WT_5X260_AS 5 260 0.93518 0.00053 0.93624 VP-55_5IP_NCT_20WT_5X280_AS 5 280 0.94289 0.00053 0.94395 Table 6.5.3-6. Array Configuration Sensitivity of the 5-Inch Pipe Container - U(10) NCT Package Array Case Array Height Array Size keff keff + 2 VP-55_5IP_NCT_10WT_3X342_AS 3 342 0.894 0.00051 0.89502 VP-55_5IP_NCT_10WT_3X360_AS 3 360 0.89826 0.00057 0.8994 VP-55_5IP_NCT_10WT_3X378_AS 3 378 0.9009 0.0006 0.9021 VP-55_5IP_NCT_10WT_4X340_AS 4 340 0.90672 0.00058 0.90788 VP-55_5IP_NCT_10WT_4X360_AS 4 360 0.91229 0.00054 0.91337 VP-55_5IP_NCT_10WT_4X380_AS 4 380 0.91405 0.0005 0.91505 VP-55_5IP_NCT_10WT_5X340_AS 5 340 0.90581 0.00059 0.90699 VP-55_5IP_NCT_10WT_5X360_AS 5 360 0.91111 0.00054 0.91219 VP-55_5IP_NCT_10WT_5X385_AS 5 385 0.91567 0.00058 0.91683 6-146

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.947 0.943 0.939 keff + 2 3X 0.935 4X 5X 0.931 0.927 230 240 250 260 270 280 290 Array SIze Figure 6.5.3-5. Array Configuration Sensitivity - U(100) NCT Package Array 0.947 0.943 0.939 keff + 2 3X 0.935 4X 5X 0.931 0.927 230 240 250 260 270 280 290 Array SIze Figure 6.5.3-6. Array Configuration Sensitivity - U(20) NCT Package Array 6-147

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.92 0.916 0.912 0.908 keff + 2 3X 0.904 4X 0.9 5X 0.896 0.892 330 340 350 360 370 380 390 Array SIze Figure 6.5.3-7. Array Configuration Sensitivity - U(10) NCT Package Array 6.5.3.4 Partial Fill Parameter Study - NCT Package Array For the partial fill parameter study of a package array under NCT, the limit-defining H/U-235 ratio for each enrichment level was held constant as the fill percentages of the 5-inch pipe container were reduced, thus reducing 235U mass, to determine the effect on keff + 2. This study shows that the fill percentages modeled are the limiting fill percentages for the limiting H/U-235 ratios specified. A decrease in keff + 2 for all partial fills that are less than the limiting fill is the expected behavior if the limiting fill percentage has been properly identified. Case VP-55_5IP_NCT_

100WT_4X252_PF010 models the Partial Fill (PF) parameter study with the 5-inch pipe container 10% full (010). Table 6.5.3-7 shows the values of keff and for the different partial moderation levels examined. Note the limiting cases are highlighted. Figure 6.5.3-8 plots the results. As the fill percentages are reduced while the limit-defining H/U-235 ratio is held constant, the value of keff + 2 also reduces, as shown in Table 6.5.3-7. This shows that the lower fill percentages (i.e.,

reduced fissile mass) are not more reactive. At a reduced fill percentage (i.e., lower fissile mass),

there is available volume to optimize H/U-235. While the increase in H/U-235 may increase keff of the system, it will not increase beyond the limiting case defined (this effect is evaluated in Section 6.4.3.2 for a single package). The following list summarizes the limit-defining cases of the partial fill study:

• For 100-wt.% U-235 enriched uranium, the limit-defining fill percentage of 95% results in the maximum value of keff + 2 of 0.93824 with a value of H/U-235 of 311.02.

• For 20-wt.% U-235 enriched uranium, the limit-defining fill percentage of 100% results in the maximum value of keff + 2 of 0.93784 with a value of H/U-235 of 179.69.

• For 10-wt.% U-235 enriched uranium, the limit-defining fill percentage of 100% results in the maximum value of keff + 2 of 0.91337 with a value of H/U-235 of 125.31.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.3-7. Partial Fill Sensitivity of the 5-inch Pipe Container - NCT Package Array Fill U-235 Case keff keff + 2 Percentage Mass (g) 100-wt.% U-235 Enriched Uranium VP-55_5IP_NCT_100WT_4X252_PF010 10 73.16 0.30317 0.00044 0.30405 VP-55_5IP_NCT_100WT_4X252_PF030 30 219.47 0.68057 0.00056 0.68169 VP-55_5IP_NCT_100WT_4X252_PF050 50 365.79 0.80609 0.00064 0.80737 VP-55_5IP_NCT_100WT_4X252_PF070 70 512.11 0.87749 0.00057 0.87863 VP-55_5IP_NCT_100WT_4X252_PF090 90 658.42 0.92621 0.00057 0.92735 VP-55_5IP_NCT_100WT_4X252_PF095 95 695.00 0.93708 0.00058 0.93824 20-wt.% U-235 Enriched Uranium VP-55_5IP_NCT_20WT_4X252_PF010 10 121.50 0.31472 0.00042 0.31556 VP-55_5IP_NCT_20WT_4X252_PF030 30 364.50 0.67497 0.00053 0.67603 VP-55_5IP_NCT_20WT_4X252_PF050 50 607.50 0.79615 0.00062 0.79739 VP-55_5IP_NCT_20WT_4X252_PF070 70 850.50 0.86682 0.00054 0.8679 VP-55_5IP_NCT_20WT_4X252_PF090 90 1093.50 0.91601 0.00061 0.91723 VP-55_5IP_NCT_20WT_4X252_PF095 95 1154.25 0.9281 0.00054 0.92918 VP-55_5IP_NCT_20WT_4X252_PF100 100 1215.00 0.9367 0.00057 0.93784 10-wt.% U-235 Enriched Uranium VP-55_5IP_NCT_10WT_4X360_PF010 10 160.50 0.30437 0.00044 0.30525 VP-55_5IP_NCT_10WT_4X360_PF030 30 481.50 0.6482 0.00052 0.64924 VP-55_5IP_NCT_10WT_4X360_PF050 50 802.50 0.76898 0.00059 0.77016 VP-55_5IP_NCT_10WT_4X360_PF070 70 1123.50 0.83981 0.00052 0.84085 VP-55_5IP_NCT_10WT_4X360_PF090 90 1444.50 0.8907 0.0006 0.8919 VP-55_5IP_NCT_10WT_4X360_PF095 95 1524.75 0.90152 0.00051 0.90254 VP-55_5IP_NCT_10WT_4X360_PF100 100 1605.00 0.91229 0.00054 0.91337 0.95 0.85 0.75 keff + 2 0.65 100-wt.%

0.55 20-wt.%

0.45 10-wt.%

0.35 0.25 0 20 40 60 80 100 Partial Fill (%)

Figure 6.5.3-8. Partial Fill Sensitivity inch Pipe NCT Package Array 6-149

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.4 5-inch Pipe with Hydrogen-Limited Contents The results of the NCT Array analysis for the 5-inch Pipe with Hydrogen-Limited contents are provided below in Table 6.5.4-1. The cases for the 10 wt% analysis model two pipes pushed to the cavity wall and the cases for the 20 wt% analysis models one pipe pushed to the cavity wall as close to the surrounding packages as possible. Each analysis starts with a pipe entirely filled with U-metal. The second case in each (VFU=0.916) corresponds to 1.25 lbs of HDPE and the remainder of the pipe filled with U-metal. Each of the following cases reduces the quantity of U-metal in the pipes and replaces it with graphite to analyze a full range of moderation ratios and determine the peak value of keff. The results of these cases are plotted for each enrichment in Figure 6.5.4-1 and Figure 6.5.4-2. The NCT Array analysis for this content demonstrates that there is a large margin to the USL for all cases.

Table 6.5.4-1. Summary 5-inch Pipe Hydrogen Limited Content NCT Array Criticality Evaluation k+2s Case a VFU 10 wt% 20 wt%

NCT_X_01 1.000 0.70545 0.74722 NCT_X_02 0.916 0.76016 0.77501 NCT_X_03 0.800 0.73486 0.73652 NCT_X_04 0.600 0.68175 0.65984 NCT_X_05 0.400 0.61170 0.56440 NCT_X_06 0.200 0.50905 0.43372 NCT_X_07 0.180 0.49644 0.41761 NCT_X_08 0.160 0.48231 0.39984 NCT_X_09 0.140 0.46694 0.38150 NCT_X_10 0.120 0.44956 0.36169 NCT_X_11 0.100 0.43067 0.33983 NCT_X_12 0.080 0.40843 0.31510 NCT_X_13 0.060 0.38033 0.28664 NCT_X_14 0.040 0.34011 0.25073 Note: a Placeholder X replaced by 010 for 10 wt% results or 020 for 20 wt% results.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.8 0.7 0.6 keff + 2s 0.5 0.4 0.3 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Volume Fraction U Figure 6.5.4-1. 10 wt% 5-inch Pipe Hydrogen Limited Content NCT Array Results 0.8 0.7 0.6 keff + 2s 0.5 0.4 0.3 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Volume Fraction U Figure 6.5.4-2. 20 wt% 5-inch Pipe Hydrogen Limited Content NCT Array Results 6-151

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.5 1S/2S Cylinder 6.5.5.1 1S Cylinder, 100-wt.% U-235, NCT Package Array For the 100-wt.% U-235 1S cylinder NCT package array analysis, three (3) 1S cylinders were modeled with a maximum uranium mass of 306 g/cylinder. The following variables represent the most reactive 1S cylinder, 100-wt.% U-235, NCT package array configuration: a maximum of 306 gU/cylinder, a maximum cylinder fill height of 22.225 cm, a cylinder spacing of 2.5 cm and a reflector thickness of 4.5 cm, 1S cylinders pushed into the bottom corner of the Versa-Pac inner cavity, a 252 package array 4 packages tall, and fissile material in the form of UO2F2.

6.5.5.1.1 Most Reactive Cylinder Configuration In this study, several values of cylinder spacing, cylinder reflector thickness, uranium mass, and cylinder fill height, were evaluated to determine the most reactive configuration. Table 6.5.5-1, Table 6.5.5-2, Table 6.5.5-3, and Table 6.5.5-4 show for 100-wt.% U-235 1S cylinder NCT package array analysis that a cylinder spacing of 2.5 cm, a reflector thickness of 4.5 cm, the maximum uranium mass of 306 gU/cylinder, and the maximum cylinder fill height of 22.225 cm is the most reactive configuration, with keff + 2 of 0.60159. The most reactive case, VP-55_1S_

100_NCT_UO2F2_4x252_307_22.225_3.5_2_in, is highlighted in these tables. Figure 6.5.5-1, Figure 6.5.5-2, Figure 6.5.5-3, and Figure 6.5.5-4 plot these trends for visual inspection.

Table 6.5.5-1. Effect of Cylinder Spacing on keff - 1S, 100-wt.% U-235, NCT Package Array Cylinder-to-Case Edge Spacing keff keff + 2 (cm)

VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_1.5_in 1.5 0.59630 0.00045 0.59720 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2_in 2.0 0.59952 0.00069 0.60090 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2.5_in 2.5 0.60073 0.00043 0.60159 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_3_in 3.0 0.59580 0.00052 0.59684 Table 6.5.5-2. Effect of Reflector Thickness on keff - 1S, 100-wt.% U-235, NCT Package Array Reflector Case Thickness keff keff + 2 (cm)

VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_3.5_2.5_in 3.5 0.59783 0.00046 0.59875 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4_2.5_in 4.0 0.59881 0.00048 0.59977 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2.5_in 4.5 0.60073 0.00043 0.60159 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_5_2.5_in 5.0 0.59964 0.00048 0.60060 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_5.5_2.5_in 5.5 0.59815 0.00058 0.59931 6-152

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.5-3. Effect of Uranium Mass on keff - 1S, 100-wt.% U-235, NCT Package Array Uranium Case keff keff + 2 Mass (g)

VP-55_1S_100_NCT_UO2F2_4x252_200_22.225_4.5_2.5_in 200 0.58458 0.00050 0.58558 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2.5_in 306 0.60073 0.00043 0.60159 Table 6.5.5-4. Effect of Fill Height on keff + 2 - 1S, 100-wt.% U-235, NCT Package Array Fill Height Case keff keff + 2 (cm)

VP-55_1S_100_NCT_UO2F2_4x252_306_10_4.5_2.5_in 10.0 0.47977 0.00045 0.48067 VP-55_1S_100_NCT_UO2F2_4x252_306_15_4.5_2.5_in 15.0 0.54706 0.00045 0.54796 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2.5_in 22.225 0.60073 0.00043 0.60159 Effect of Cylinder Spacing on keff + 2 0.62 0.615 0.61 0.605 k-eff + 2 0.6 0.595 0.59 0.585 0.58 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25 Cylinder Spacing (cm)

Figure 6.5.5-1. Effect of Cylinder Spacing - 1S, 100-wt.% U-235, NCT Package Array 6-153

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Cylinder Spacing on keff + 2 0.62 0.615 0.61 0.605 k-eff + 2 0.6 0.595 0.59 0.585 0.58 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25 Cylinder Spacing (cm)

Figure 6.5.5-2. Effect of Reflector Thickness - 1S, 100-wt.% U-235, NCT Package Array Effect of Uranium Mass on keff + 2 0.615 0.61 0.605 0.6 k-eff + 2 0.595 0.59 0.585 0.58 0.575 150 200 250 300 350 Mass Uranium (g)

Figure 6.5.5-3. Effect of Uranium Mass - 1S, 100-wt.% U-235, NCT Package Array 6-154

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Fill Height on keff + 2 0.65 0.63 0.61 0.59 0.57 k-eff + 2 0.55 0.53 0.51 0.49 0.47 0.45 8 12 16 20 24 Fill Height (cm)

Figure 6.5.5-4. Effect of Fill Height - 1S, 100-wt.% U-235, NCT Package Array 6.5.5.1.2 Cylinder Positioning Sensitivity Study As shown in Table 6.5.5-5, modeling the 100-wt.% U-235 1S cylinder group in the center of the inner cavity produces the bounding cylinder position for the NCT package array, with keff + 2 equivalent to 0.60159.

Table 6.5.5-5. Effect of Cylinder Positioning on keff + 2 - 1S, 100-wt.% U-235, NCT Package Array Case Centering keff keff + 2 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2.5_in None 0.60073 0.00043 0.60159 Radial +

VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2.5_POS_1_in 0.59320 0.00052 0.59424 Axial VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2.5_POS_2_in Axial 0.59426 0.00053 0.59532 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2.5_POS_3_in Radial 0.59836 0.00046 0.59928 6.5.5.1.3 Array Configuration As shown in Table 6.5.5-6, reducing or increasing the height of packages in the NCT package array, while modeling at least 252 packages, results in significantly reduced values of keff + 2.

Therefore, an array of 252 packages stacked four packages tall is the bounding array configuration for 1S cylinders with 100-wt.% U-235 in the NCT package array evaluation.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.5-6. Effect of Array Configuration on keff + 2- 1S, 100-wt.% U-235, NCT Package Array Array Total Case keff keff + 2 Height Packages VP-55_1S_100_NCT_UO2F2_3x255_306_22.225_4.5_2.5 3 255 0.59904 0.00048 0.60000 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2.5_in 4 252 0.60073 0.00043 0.60159 VP-55_1S_100_NCT_UO2F2_5x260_306_22.225_4.5_2.5 5 260 0.59979 0.00049 0.60077 6.5.5.1.4 UF6 Fissile Solution Sensitivity Study As shown in Table 6.5.5-7 and Figure 6.5.5-5, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly. Therefore, UO2F2 is the bounding fissile configuration for 1S cylinders with 100-wt.% U-235, NCT package array evaluation.

Table 6.5.5-7. Effect of UF6 on keff + 2 - 1S, 100-wt.% U-235, NCT Package Array Cylinder Case Spacing keff keff + 2 (cm)

Uranyl Fluoride (UO2F2)

VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_1.5_in 1.5 0.59630 0.00045 0.59720 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2_in 2.0 0.59952 0.00069 0.60090 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_2.5_in 2.5 0.60073 0.00043 0.60159 VP-55_1S_100_NCT_UO2F2_4x252_306_22.225_4.5_3_in 3.0 0.59580 0.00052 0.59684 Uranium Hexafluoride (UF6)

VP-55_1S_100_NCT_UF6_4x252_306_22.225_1.5_in 1.5 0.57346 0.00047 0.5744 VP-55_1S_100_NCT_UF6_4x252_306_22.225_2_in 2.0 0.58032 0.00047 0.58126 VP-55_1S_100_NCT_UF6_4x252_306_22.225_2.5_in 2.5 0.58136 0.00051 0.58238 VP-55_1S_100_NCT_UF6_4x252_306_22.225_3_in 3.0 0.578 0.00046 0.57892 Effect of UF6 Fissile Solution on keff 0.605 0.6 0.595 k-eff + 2 0.59 0.585 UO2F2 0.58 UF6 0.575 0.57 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25 Cylinder Spacing (cm)

Figure 6.5.5-5. Effect of UF6 on keff - 1S, 100-wt.% U-235, NCT Package Array 6-156

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.5.2 2S Cylinder, 100-wt.% U-235, NCT Package Array For the 100-wt.% U-235 2S cylinder NCT package array analysis, one (1) 2S cylinder was modeled with a maximum uranium mass of 1497 g/cylinder. The following variables represent the most reactive 2S cylinder, 100-wt.% U-235, NCT package array configuration: a partial uranium mass of 1250 gU/cylinder, a maximum cylinder fill height of 20.0025 cm, a reflector thickness of 0.5 cm, the 2S cylinder modeled in the bottom corner of the Versa-Pac inner cavity, and fissile material in the form of UO2F2.

6.5.5.2.1 Most Reactive Cylinder Configuration In this study, several values of uranium mass, cylinder fill height, and cylinder spacing were evaluated to determine the most reactive configuration. Table 6.5.5-8, Table 6.5.5-9, and Table 6.5.5-10 show for 100-wt.% U-235 2S cylinder NCT package array analysis that a reflector thickness of 0.5 cm, a partial uranium mass of 1250 gU/cylinder, and the maximum cylinder fill height of 20.0025 cm is the most reactive configuration, with keff + 2 of 0.64567. The most reactive case, VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5.5_in, is highlighted in these tables. Figure 6.5.5-6, Figure 6.5.5-7, and Figure 6.5.5-8 plot these trends for visual inspection.

Table 6.5.5-8. Effect of Reflector Thickness on keff - 2S, 100-wt.% U-235, NCT Package Array Reflector Case Thickness keff keff + 2 (cm)

VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_4.5_in 4.5 0.64239 0.00050 0.64339 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5_in 5.0 0.64321 0.00051 0.64423 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5.5_in 5.5 0.64457 0.00055 0.64567 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_6_in 6.0 0.64297 0.00055 0.64407 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_6.5_in 6.5 0.64194 0.00065 0.64324 Table 6.5.5-9. Effect of Uranium Mass on keff - 2S, 100-wt.% U-235, NCT Package Array Uranium Case keff keff + 2 Mass (g)

VP-55_2S_100_NCT_UO2F2_4x252_750_20.003_5.5_in 750 0.63894 0.00057 0.64008 VP-55_2S_100_NCT_UO2F2_4x252_1000_20.003_5.5_in 1000 0.64383 0.00048 0.64479 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5.5_in 1250 0.64457 0.00055 0.64567 VP-55_2S_100_NCT_UO2F2_4x252_1497_20.003_5.5_in 1497 0.64279 0.00058 0.64395 Table 6.5.5-10. Effect of Fill Height on keff - 2S, 100-wt.% U-235, NCT Package Array Fill Height Case keff keff + 2 (cm)

VP-55_2S_100_NCT_UO2F2_4x252_1250_10_5.5_in 10.0 0.52056 0.00040 0.52136 VP-55_2S_100_NCT_UO2F2_4x252_1250_15_5.5_in 15.0 0.59623 0.00049 0.59721 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5.5_in 20.0025 0.64457 0.00055 0.64567 6-157

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Cylinder Spacing on keff + 2 0.665 0.66 0.655 0.65 k-eff + 2 0.645 0.64 0.635 0.63 0.625 4 4.5 5 5.5 6 6.5 7 Cylinder Spacing (cm)

Figure 6.5.5-6. Effect of Reflector Thickness - 2S, 100-wt.% U-235, NCT Package Array Effect of Uranium Mass on keff + 2 0.665 0.66 0.655 0.65 k-eff + 2 0.645 0.64 0.635 0.63 0.625 600 800 1000 1200 1400 1600 H/U-235 Figure 6.5.5-7. Effect of Uranium Mass - 2S, 100-wt.% U-235, NCT Package Array 6-158

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Fill Height on keff + 2 0.66 0.64 0.62 0.6 k-eff + 2 0.58 0.56 0.54 0.52 0.5 5 8 11 14 17 20 23 H/U-235 Figure 6.5.5-8. Effect of Fill Height - 2S, 100-wt.% U-235, NCT Package Array 6.5.5.2.2 Cylinder Positioning Sensitivity Study As shown in Table 6.5.5-11 modeling the 100-wt.% U-235 2S cylinder in the center of the inner cavity produces the bounding cylinder position for the NCT package array, with keff + 2 equivalent to 0.64567.

Table 6.5.5-11. Effect of Cylinder Group Positioning on keff - 2S, 20-wt.% U-235, NCT Package Array Case Centering keff keff + 2 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5.5_in None 0.64457 0.00055 0.64567 Radial +

VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5.5_POS_1_in 0.63582 0.00054 0.63690 Axial VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5.5_POS_2_in Axial 0.63917 0.00058 0.64033 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5.5_POS_3_in Radial 0.64227 0.00051 0.64329 6.5.5.2.3 Array Configuration As shown in Table 6.5.5-12, reducing or increasing the height of packages in the NCT package array, while modeling at least 252 packages, results in significantly reduced values of keff + 2.

Therefore, an array of 252 packages stacked four packages tall is the bounding array configuration for 100-wt.% U-235 2S cylinders in the NCT package array evaluation.

Table 6.5.5-12. Effect of Array Configuration on keff - 2S, 100-wt.% U-235, NCT Package Array Array Total Case keff keff + 2 Height Packages VP-55_2S_100_NCT_UO2F2_3x255_1250_20.003_5.5 3 255 0.64299 0.00053 0.64405 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5.5_in 4 252 0.64457 0.00055 0.64567 VP-55_2S_100_NCT_UO2F2_5x260_1250_20.003_5.5 5 260 0.64302 0.00051 0.64404 6-159

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.5.2.4 UF6 Fissile Solution Sensitivity Study As shown in Table 6.5.5-13 and Figure 6.5.5-9, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly. Therefore, UO2F2 is the bounding fissile configuration for 2S cylinders with 100-wt.% U-235 in the NCT package array evaluation.

Table 6.5.5-13. Effect of UF6 on keff - 2S, 100-wt.% U-235, NCT Package Array Cylinder Case Spacing keff keff + 2 (cm)

Uranyl Fluoride (UO2F2)

VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_4.5_in 4.5 0.64239 0.00050 0.64339 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5_in 5.0 0.64321 0.00051 0.64423 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_5.5_in 5.5 0.64457 0.00055 0.64567 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_6_in 6.0 0.64297 0.00055 0.64407 VP-55_2S_100_NCT_UO2F2_4x252_1250_20.003_6.5_in 6.5 0.64194 0.00065 0.64324 Uranium Hexafluoride (UF6)

VP-55_2S_100_NCT_UF6_4x252_1250_20.003_3_in 3.0 0.58344 0.00049 0.58442 VP-55_2S_100_NCT_UF6_4x252_1250_20.003_4_in 4.0 0.60327 0.00058 0.60443 VP-55_2S_100_NCT_UF6_4x252_1250_20.003_5_in 5.0 0.61113 0.00049 0.61211 VP-55_2S_100_NCT_UF6_4x252_1250_20.003_6_in 6.0 0.61059 0.00050 0.61159 VP-55_2S_100_NCT_UF6_4x252_1250_20.003_7_in 7.0 0.60767 0.00046 0.60859 VP-55_2S_100_NCT_UF6_4x252_1250_20.003_8_in 8.0 0.60406 0.00057 0.60520 Effect of UF6 Fissile Solution on keff + 2 0.65 0.64 0.63 k-eff + 2 0.62 0.61 UO2F2 0.6 UF6 0.59 0.58 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 Cylinder Spacing (cm)

Figure 6.5.5-9. Effect of UF6 on keff - 2S, 100-wt.% U-235, NCT Package Array 6-160

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.5.3 1S Cylinder, 20-wt.% U-235, NCT Package Array For the 20-wt.% U-235 1S cylinder NCT package array analysis, seven (7) 1S cylinders were modeled with a maximum uranium mass of 307 g/cylinder. The following variables represent the most reactive 1S cylinder, 20-wt.% U-235, NCT package array configuration: a maximum mass of 307 gU/cylinder, a maximum cylinder fill height of 22.225 cm, a cylinder spacing of 2.0 cm and a reflector thickness of 3.5 cm, an array configuration of 252 packages stacked 4 tall, cylinders pushed into a corner of the Versa-Pac inner cavity, and fissile material in the form of UO2F2.

6.5.5.3.1 Most Reactive Cylinder Configuration In this study, several values of uranium mass, cylinder fill height, and cylinder spacing were evaluated to determine the most reactive configuration. Table 6.5.5-14, Table 6.5.5-15, Table 6.5.5-16, and Table 6-127 show that a cylinder spacing of 3.5 cm, a reflector thickness of 2.0 cm, the maximum uranium mass of 307 gU/cylinder, and the maximum cylinder fill height of 22.225 cm is the most reactive 20-wt.% U-235 1S cylinder NCT package array configuration, with keff + 2 of 0.68991. The most reactive case, VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_

3.5_2_in, is highlighted in these tables. Figure 6.5.5-10, Figure 6.5.5-11, Figure 6.5.5-12, and Figure 6.5.5-13 plot these trends for visual inspection.

Table 6.5.5-14. Effect of Cylinder Spacing on keff - 1S, 20-wt.% U-235, NCT Package Array Cylinder-to-Case Edge Spacing keff keff + 2 (cm)

VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_1.5_in 1.50 0.68586 0.00049 0.68684 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_1.75_in 1.75 0.68820 0.00051 0.68922 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2_in 2.00 0.68879 0.00056 0.68991 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2.25_in 2.25 0.68564 0.00052 0.68668 Table 6.5.5-15. Effect of Reflector Thickness on keff - 1S, 20-wt.% U-235, NCT Package Array Reflector Case Thickness keff keff + 2 (cm)

VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3_2_in 3.0 0.68844 0.00053 0.68950 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2_in 3.5 0.68879 0.00056 0.68991 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_4_2_in 4.0 0.68791 0.00043 0.68877 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_4.5_2_in 4.5 0.68634 0.00048 0.68730 Table 6.5.5-16. Effect of Uranium Mass on keff - 1S, 20-wt.% U-235, NCT Package Array Uranium Case keff keff + 2 Mass (g)

VP-55_1S_020_NCT_UO2F2_4x252_200_22.225_3.5_2_in 200 0.64482 0.00046 0.64574 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2_in 307 0.68879 0.00056 0.68991 6-161

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.5-17. Effect of Fill Height on keff - 1S, 20-wt.% U-235, NCT Package Array Fill Height Case keff keff + 2 (cm)

VP-55_1S_020_NCT_UO2F2_4x252_307_10_3.5_2_in 10.0 0.54346 0.00048 0.54442 VP-55_1S_020_NCT_UO2F2_4x252_307_15_3.5_2_in 15.0 0.62989 0.00047 0.63083 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2_in 22.2250 0.68879 0.00056 0.68991 Effect of Cylinder Spacing on keff 0.709 0.704 0.699 0.694 k-eff + 2 0.689 0.684 0.679 0.674 0.669 1.25 1.5 1.75 2 2.25 2.5 Cylinder Spacing (cm)

Figure 6.5.5-10. Effect of Cylinder Spacing - 1S, 20-wt.% U-235, NCT Package Array Effect of Reflector Thickness on keff 0.709 0.704 0.699 0.694 k-eff + 2 0.689 0.684 0.679 0.674 0.669 2.5 3 3.5 4 4.5 5 Reflector Thickness (cm)

Figure 6.5.5-11. Effect of Reflector Thickness - 1S, 20-wt.% U-235, NCT Package Array 6-162

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Uranium Mass on keff + 2 0.7 0.69 0.68 k-eff + 2 0.67 0.66 0.65 0.64 0.63 150 200 250 300 350 H/U-235 Figure 6.5.5-12. Effect of Uranium Mass - 1S, 20-wt.% U-235, NCT Package Array Effect of Fill Height on keff + 2 0.72 0.7 0.68 0.66 k-eff + 2 0.64 0.62 0.6 0.58 0.56 0.54 0.52 8 10 12 14 16 18 20 22 24 H/U-235 Figure 6.5.5-13. Effect of Fill Height - 1S, 20-wt.% U-235, NCT Package Array 6-163

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.5.3.2 Cylinder Positioning Sensitivity Study As shown in Table 6.5.5-18, modeling the 20-wt.% U-235 1S cylinder group in the center of the inner cavity produces the bounding cylinder position for the NCT package array, with keff + 2 equivalent to 0.68991.

Table 6.5.5-18. Effect of Cylinder Group Positioning on keff - 1S, 20-wt.% U-235, NCT Package Array Case Centering keff keff + 2 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2_in None 0.68879 0.00056 0.68991 Radial +

VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2_POS_1_in 0.67803 0.00048 0.67899 Axial VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2_POS_2_in Axial 0.68000 0.00054 0.68108 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2_POS_3_in Radial 0.68726 0.00055 0.68836 6.5.5.3.3 Array Configuration As shown in Table 6.5.5-19, reducing or increasing the height of packages in the NCT package array, while modeling at least 252 packages, results in significantly reduced values of keff + 2.

Therefore, an array of 252 packages stacked four packages tall is the bounding array configuration for 20-wt.% U-235 1S cylinders in the NCT package array evaluation.

Table 6.5.5-19. Effect of Array Configuration on keff - 1S, 20-wt.% U-235, NCT Package Array Array Total Case keff keff + 2 Height Packages VP-55_1S_020_NCT_UO2F2_3x255_307_22.225_3.5_2_in 3 255 0.68560 0.00047 0.68654 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2_in 4 252 0.68879 0.00056 0.68991 VP-55_1S_020_NCT_UO2F2_5x260_307_22.225_3.5_2_in 5 260 0.68778 0.00048 0.68874 6-164

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.5.3.4 UF6 Fissile Solution Sensitivity Study As shown in Table 6.5.5-20 and Figure 6.5.5-14, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly for the 1S, 20-wt.% U-235, NCT package array evaluation.

Therefore, UO2F2 is the bounding fissile configuration for 20-wt.% U-235 1S cylinders in the NCT package array evaluation.

Table 6.5.5-20. Effect of UF6 on keff + 2 - 1S, 20-wt.% U-235, NCT Package Array Cylinder Case Spacing keff keff + 2 (cm)

Uranyl Fluoride (UO2F2)

VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_1.5_in 1.50 0.68586 0.00049 0.68684 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_1.75_in 1.75 0.68820 0.00051 0.68922 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2_in 2.00 0.68879 0.00056 0.68991 VP-55_1S_020_NCT_UO2F2_4x252_307_22.225_3.5_2.25_in 2.25 0.68564 0.00052 0.68668 Uranium Hexafluoride (UF6)

VP-55_1S_020_NCT_UF6_4x252_307_22.225_1.5_in 1.50 0.66344 0.00052 0.66448 VP-55_1S_020_NCT_UF6_4x252_307_22.225_1.75_in 1.75 0.66824 0.00046 0.66916 VP-55_1S_020_NCT_UF6_4x252_307_22.225_2_in 2.00 0.66922 0.00046 0.67014 VP-55_1S_020_NCT_UF6_4x252_307_22.225_2.25_in 2.25 0.67009 0.00054 0.67117 VP-55_1S_020_NCT_UF6_4x252_307_22.225_2.5_in 2.50 0.66564 0.00049 0.66662 VP-55_1S_020_NCT_UF6_4x252_307_22.225_2.75_in 2.75 0.66010 0.00054 0.66118 Effect of UF6 Fissile Solution on keff 0.695 0.69 0.685 0.68 k-eff + 2 0.675 UO2F2 0.67 UF6 0.665 0.66 0.655 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 Cylinder Spacing (cm)

Figure 6.5.5-14. Effect of UF6 on keff - 1S, 20-wt.% U-235, NCT Package Array 6-165

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.5.4 2S Cylinder, 20-wt.% U-235, NCT Package Array For the 20-wt.% U-235 2S cylinder NCT package array analysis, three (3) 2S cylinders were modeled with a maximum uranium mass of 1502 g/cylinder. The following variables represent the most reactive 2S cylinder, 20-wt.% U-235, NCT package array configuration: a maximum of 1502 gU/cylinder, a maximum cylinder fill height of 20.0025 cm, a cylinder spacing of 4.5 cm and a reflector thickness of 0.5 cm, 2S cylinders pushed into the bottom corner of the Versa-Pac inner cavity, an array of 252 packages stacked 4 tall, and fissile material in the form of UO2F2.

6.5.5.4.1 Most Reactive Cylinder Configuration In this study, several values of uranium mass, cylinder fill height, and cylinder spacing were evaluated to determine the most reactive configuration. Table 6.5.5-21, Table 6.5.5-22, Table 6.5.5-23, and Table 6.5.5-24 show for 20-wt.% U-235 2S cylinder NCT package array analysis that a cylinder spacing of 4.5 cm, a reflector thickness of 0.5 cm, the maximum uranium mass of 1502 gU/cylinder, and the maximum cylinder fill height of 20.0025 cm is the most reactive configuration, with keff + 2 of 0.67286. The most reactive case, VP-55_2S_020_NCT_UO2F2_

4x252_1502_20.003_4.5_0.5_in, is highlighted in these tables. Figure 6.5.5-15, Figure 6.5.5-16, Figure 6.5.5-17, and Figure 6.5.5-18 plot these trends for visual inspection.

Table 6.5.5-21. Effect of Cylinder Spacing on keff - 2S, 20-wt.% U-235, NCT Package Array Cylinder-to-Case Edge Spacing keff keff + 2 (cm)

VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.01_in 0.01 0.67038 0.00056 0.67150 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.5_in 0.50 0.67192 0.00047 0.67286 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_1_in 1.00 0.66952 0.00056 0.67064 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_1.5_in 1.50 0.66596 0.00068 0.66732 Table 6.5.5-22. Effect of Reflector Thickness on keff - 2S, 20-wt.% U-235, NCT Package Array Reflector Case Thickness keff keff + 2 (cm)

VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_3_0.5_in 3.0 0.66632 0.00063 0.66758 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_3.5_0.5_in 3.5 0.66988 0.00051 0.67090 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4_0.5_in 4.0 0.67165 0.00055 0.67275 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.5_in 4.5 0.67192 0.00047 0.67286 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_5_0.5_in 5.0 0.66918 0.00051 0.67020 Table 6.5.5-23. Effect of Uranium Mass on keff - 2S, 20-wt.% U-235, NCT Package Array Uranium Case keff keff + 2 Mass (g)

VP-55_2S_020_NCT_UO2F2_4x252_500_20.003_4.5_0.5_in 500 0.59499 0.00045 0.59589 VP-55_2S_020_NCT_UO2F2_4x252_1000_20.003_4.5_0.5_in 1000 0.65905 0.00051 0.66007 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.5_in 1502 0.67192 0.00047 0.67286 6-166

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.5.5-24. Effect of Fill Height on keff - 2S, 20-wt.% U-235, NCT Package Array Fill Height Case keff keff + 2 (cm)

VP-55_2S_020_NCT_UO2F2_4x252_1502_10_4.5_0.5_in 10.0 0.51802 0.00051 0.51904 VP-55_2S_020_NCT_UO2F2_4x252_1502_15_4.5_0.5_in 15.0 0.61239 0.00061 0.61361 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.5_in 20.0025 0.67192 0.00047 0.67286 Effect of Cylinder Spacing on keff 0.69 0.685 0.68 0.675 k-eff + 2 0.67 0.665 0.66 0.655 0.65 0 0.25 0.5 0.75 1 1.25 1.5 1.75 Cylinder Spacing (cm)

Figure 6.5.5-15. Effect of Cylinder Spacing - 2S, 20-wt.% U-235, NCT Package Array Effect of Reflector Thickness on keff 0.69 0.685 0.68 0.675 k-eff + 2 0.67 0.665 0.66 0.655 0.65 2.5 3 3.5 4 4.5 5 5.5 Reflector Thickness (cm)

Figure 6.5.5-16. Effect of Reflector Thickness - 2S, 20-wt.% U-235, NCT Package Array 6-167

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Uranium Mass on keff 0.7 0.68 0.66 k-eff + 2 0.64 0.62 0.6 0.58 250 450 650 850 1050 1250 1450 1650 H/U-235 Figure 6.5.5-17. Effect of Uranium Mass - 2S, 20-wt.% U-235, NCT Package Array Effect of Fill Height on keff 0.7 0.66 k-eff + 2 0.62 0.58 0.54 0.5 5 8 11 14 17 20 23 H/U-235 Figure 6.5.5-18. Effect of Fill Height - 2S, 20-wt.% U-235, NCT Package Array 6-168

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.5.4.2 Cylinder Positioning Sensitivity Study As shown in Table 6.5.5-25, modeling the 20-wt.% U-235 2S cylinder group in the center of the inner cavity produces the bounding cylinder position for the NCT package array, with keff + 2 equivalent to 0.67286.

Table 6.5.5-25. Effect of Cylinder Group Positioning on keff - 2S, 20-wt.% U-235, NCT Package Array Case Centering keff keff + 2 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.5_in None 0.67192 0.00047 0.67286 Radial +

VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.5_POS_1_in 0.66060 0.00052 0.66164 Axial VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.5_POS_2_in Axial 0.66376 0.00051 0.66478 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.5_POS_3_in Radial 0.66825 0.00055 0.66935 6.5.5.4.3 Array Configuration As shown in Table 6.5.5-26, reducing or increasing the height of packages in the NCT package array, while modeling at least 252 packages to satisfy a CSI of 1.0, results in significantly reduced values of keff + 2. Therefore, an array of 252 packages stacked four packages tall is the bounding array configuration for 20-wt.% U-235 2S cylinders in the NCT package array evaluation.

Table 6.5.5-26. Effect of Array Configuration on keff - 2S, 20-wt.% U-235, NCT Package Array Array Total Case keff keff + 2 Height Packages VP-55_2S_020_NCT_UO2F2_3x255_1502_20.003_4.5_0.5 3 255 0.66905 0.00054 0.67013 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.5_in 4 252 0.67192 0.00047 0.67286 VP-55_2S_020_NCT_UO2F2_5x260_1502_20.003_4.5_0.5 5 260 0.67059 0.00048 0.67155 6-169

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.5.4.4 UF6 Fissile Solution Sensitivity Study As shown in Table 6.5.5-27 and Figure 6.5.5-19, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly for the 2S, 20-wt.% U-235, NCT package array evaluation.

Therefore, UO2F2 is the bounding fissile configuration for 20-wt.% U-235 2S cylinders in the NCT package array evaluation.

Table 6.5.5-27. Effect of UF6 on keff - 2S, 20-wt.% U-235, NCT Package Array Cylinder Case Spacing keff keff + 2 (cm)

Uranyl Fluoride (UO2F2)

VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.01_in 0.01 0.67038 0.00056 0.67150 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_0.5_in 0.50 0.67192 0.00047 0.67286 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_1_in 1.00 0.66952 0.00056 0.67064 VP-55_2S_020_NCT_UO2F2_4x252_1502_20.003_4.5_1.5_in 1.50 0.66596 0.00068 0.66732 Uranium Hexafluoride (UF6)

VP-55_2S_020_NCT_UF6_4x252_1502_0.01_in 0.01 0.63432 0.00049 0.6353 VP-55_2S_020_NCT_UF6_4x252_1502_0.5_in 0.50 0.63465 0.00049 0.63563 VP-55_2S_020_NCT_UF6_4x252_1502_1_in 1.00 0.63186 0.00059 0.63304 VP-55_2S_020_NCT_UF6_4x252_1502_1.5_in 1.50 0.62833 0.00048 0.62929 Effect of UF6 Fissile Solution on keff 0.68 0.67 0.66 k-eff + 2 0.65 UO2F2 0.64 UF6 0.63 0.62 0.00 0.50 1.00 1.50 Cylinder Spacing (cm)

Figure 6.5.5-19. Effect of UF6 on keff - 2S, 20-wt.% U-235, NCT Package Array 6-170

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.6 High-Capacity Basket with Hydrogen-Limited Contents 6.5.6.1 Bounding CPVC Compound Analysis As discussed in Section 6.3.4.6.1, the bounding CPVC compounds must be determined for the NCT array evaluation. First, the optimally moderated case with nominal CPVC compound is determined. As shown in Table 6.5.6-1 and Figure 6.5.6-1, a UC Volume Fraction of 0.916 is bounding for the NCT array with nominal CPVC. Therefore, this fissile-moderator combination is used to determine the bounding CPVC compound.

Table 6.5.6-1. Optimally Moderated CPVC Compound Homogeneous Results - NCT Array Case VFUC keff + 2 01 1.000 0.84942 02 0.916 0.87756 03 0.800 0.84487 04 0.600 0.77738 05 0.400 0.69122 06 0.200 0.56470 07 0.180 0.54707 08 0.160 0.52957 09 0.140 0.50908 10 0.120 0.48705 11 0.100 0.46198 12 0.080 0.43316 13 0.060 0.39549 14 0.040 0.34659 1

0.9 0.8 0.7 keff + 2 0.6 0.5 0.4 0.3 0 0.2 0.4 0.6 0.8 1 Volume Fraction Uranium Carbide Figure 6.5.6-1. UC Volume Fraction vs. keff for Nominal HCB Compounds - NCT Array 6-171

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 With the optimally moderated case determined, the Chlorine percent and density of the CPVC compound are varied to determine the bounding values. As shown in Table 6.5.6-2 and Figure 6.5.6-2 for the NCT array, the maximum Chlorine percentage and the minimum density produce the largest keff. Therefore, the bounding CPVC composition for the NCT array models the maximum Chlorine percentage and the minimum density.

Table 6.5.6-2. Bounding CPVC Compound Evaluation keff Results - NCT Array Compound Chlorine Case Density Weight keff + 2 (g/cm3) Percent 1-1 60 0.87346 1-2 66 0.87995 1.45 1-3 69 0.88136 1-4 72 0.88213 2-1 60 0.87252 2-2 66 0.87885 1.48 2-3 69 0.87981 2-4 72 0.88162 3-1 60 0.87064 3-2 66 0.87738 1.51 3-3 69 0.87974 3-4 72 0.88144 4-1 60 0.86911 4-2 66 0.87669 1.54 4-3 69 0.87900 4-4 72 0.88029 0.884 0.882 0.880 0.878 keff + 2 1.45 g/cc 0.876 1.48 g/cc 0.874 1.51 g/cc 0.872 1.54 g/cc 0.870 0.868 58 60 62 64 66 68 70 72 74 Chlorine Weight Percent Figure 6.5.6-2. CPVC Compound Analysis Chlorine wt.% vs. keff - NCT Array 6-172

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.5.6.2 Homogeneous NCT Array Evaluation The results of the NCT Array analysis for the HCB with Hydrogen-Limited contents are provided below in Table 6.5.6-3. The cases model the HCB of each package rotated such that one pipe is as close to another pipe of the surrounding packages as possible. The moderator pipe and separator plate model their respective bounding CPVC composition listed in Section 6.3.2.11.

The analysis starts with the pipes entirely filled with UC. The second case in each (VFU=0.916) corresponds to 1.25 lb (567 g) of HDPE and the remainder of each 5-inch pipe filled with UC. The quantity of UC in the 5-inch pipes in each of the following cases is reduced and replaced with graphite to analyze a full range of moderation ratios and determine the peak value of keff. The results of these cases are plotted in Figure 6.5.6-3. The NCT Array evaluation demonstrates that there is a large margin to the USL for all cases.

Table 6.5.6-3. NCT Array HCB Homogeneous Case Summary wt.% 235U UC Case VFUC keff + 2 1 1.000 0.85230 2 0.916 0.88187 3 0.800 0.84884 4 0.600 0.78178 5 0.400 0.69508 6 0.200 0.56915 7 0.180 0.55248 8 0.160 0.53450 9 0.140 0.51488 10 0.120 0.49196 11 0.100 0.46651 12 0.080 0.43740 13 0.060 0.40007 14 0.040 0.35018 0.9 0.8 0.7 keff + 2 0.6 0.5 0.4 0.3 0 0.2 0.4 0.6 0.8 1 Volume Fraction Uranium Carbide Figure 6.5.6-3. NCT Array Volume Fraction UC vs. keff 6-173

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 As described in Section 6.3.4.6, three different configurations of the HCB are analyzed. Results for the NCT HCB study are shown in Table 6.5.6-4. As the results show, keff increases slightly when the 5-inch pipes are displaced outside of the HCB. As the pipes are modeled nominally at the bottom of the inner cavity of the VP-55, displacing the pipes up only increases the amount of fissile material outside of the CPVC components, thus, increasing keff. Second, keff increases upon removal of the separator plate or a moderator pipe but keff remains less than the USL for both. Finally, complete removal of the HCB (i.e., modeling all moderator/separator components as void) results in a decrease in keff over the baseline case modeling all the CPVC components.

Therefore, based on the keff results of the HCB configurations in this NCT array study, it is acceptable to allow the moderator/separator components of the HCB to be classified as Category B safety items, as the failure of any individual component would not result in a condition adversely affecting public health and safety.

Table 6.5.6-4. HCB Study Results - NCT Array Case keff + 2 (keff + 2)

Baseline 0.88187 --

Pipe Up 0.88275 0.00088 No HCB Plate 0.88906 0.00719 One HCB Pipe 0.88935 0.00748 No HCB 0.87281 -0.00906 6-174

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6 Evaluation of Package Arrays Under Hypothetical Accident Conditions For the HAC Package Array Evaluation, the packages were modeled at reduced dimensions due to damage and with reduced tolerances per Section 6.3.1. Flooding studies are done for all VP-55 contents under HAC to determine any effect of flooding on keff. The arrays were modeled with full water reflection of 12 inches (30.48 cm) in all three dimensions. The packages were arranged in a hexagonal pitch. The size of the HAC arrays for each content type are as listed in Table 6.6-1 with the 2N = 72 HAC array shown in Figure 6.6-1, the 2N = 105 HAC array shown in Figure 6.6-2, and the 2N = 144 HAC array shown in Figure 6.6-3.

Table 6.6-1. HAC Package Array Configurations U-235 Enrichments HAC Array Size Contents (wt.%) (2N)

Standard All enrichments 105 100, 20 (605 gU-235),

Hydrogen- 144 10, 5 limited 20 (635 g U-235) 105 100, 20 105 5-inch Pipe 10, 5 144 5-inch Pipe 20, 10 (UO2) 105 Hydrogen-limited 10 (U Metal) 72 1S/2S 100, 20 105 20 (UC) 72 HCB 20 (U3O8) 144 Figure 6.6-1. Top and Side Views of 2N = 72 HAC Package Array 6-175

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.6-2. Top and Side Views of 2N = 105 HAC Package Array Figure 6.6-3. Top and Side Views of 2N = 144 HAC Package Array 6-176

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.1 Standard Configuration The following cases analyze the VP-55 with standard contents in the HAC package model presented in Section 6.3.1 in a hexagonally pitched 2N array of 105 packages (7x5x3 packages, array 3-3 per Section 6.3.4.1.5), equivalent to a CSI of 1.0. This array configuration was chosen to minimize neutron leakage for a 105-package array in a cuboid shape. Flooding is evaluated, and the array is reflected by at least 12 in. (30.48 cm) of full-density water. All fissile material is moderated by unlimited high-density polyethylene in addition to close water reflection from flooding, where applicable. An HDPE inner cavity reflector is also evaluated.

6.6.1.1 100-wt.% 235U As shown in Table 6.6.1-1, a 235U mass of 360 g is the bounding fissile mass with keff of 0.93743 less than the USL of 0.9399 for an inner cavity full of HDPE. In addition, the homogeneous fissile study was done for a dry inner cavity. As shown in Table 6.6.1-2, a dry inner cavity is bounded by an HDPE inner cavity by a margin of approximately 0.035. The curves in Figure 6.6.1-1 and Figure 6.6.1-2 show that the optimally moderated cases are captured. The HDPE volume fraction study examines various volume fractions of the HDPE inner cavity reflector. This study starts with the bounding HDPE case in Table 6.6.1-1. As shown in Table 6.6.1-3, reducing the volume fraction of HDPE present in the inner cavity results in significant reductions in keff. Therefore, an HDPE cavity volume fraction of 1.0 is bounding for 100-wt.% 235U HAC array. A heterogeneous study is done to determine which fissile configuration is bounding. This study is done with the inner cavity dry. As shown in Table 6.6.1-4 and Figure 6.6.1-3, a heterogeneous configuration is bounded by the homogeneous configuration for this enrichment. Also, Figure 6.6.1-4 shows that as the particle size decreases and the system approaches homogeneity, the bounding result approaches the homogeneous results.

The fissile position study examines the sensitivity of the system to the position of the fissile spheres. In the homogeneous study, the fissile spheres were placed as close together axially and radially as possible. This study examines additional positions to verify that the default fissile position is bounding. As shown in Table 6.6.1-5, modeling the fissile spheres as close together as possible is bounding of other possible fissile positions. Therefore, the default fissile position is bounding for the 100-wt.% HAC array.

The flooding study examines the effect of various flooding configurations on keff for 100-wt.% 235U.

Note that the Inner Cavity flooding configuration (FLD1) is not examined as the full-density HDPE inner cavity reflector bounds FLD1 because of HDPEs higher hydrogen density over water. As shown in Table 6.6.1-6 and Figure 6.6.1-5, several cases result in increases in keff over the non-flooded case. However, these increases in keff are not statistically significant over the unflooded case (the baseline result). Therefore, for 100-wt.% 235U, the unflooded configuration is bounding.

The final study examines the sensitivity of the system to the height and configuration of packages in an array. The baseline case models a 4x high array and this study examines 3x and 5x high arrays. In addition, varying rows and columns of packages per array height are examined. As shown in Table 6.6.1-7, several other array sizes result in increases in keff. However, none of these increases are statistically significant. Therefore, the 4-3 array of the baseline case is bounding for the 100-wt.% 235U HAC array.

As demonstrated, the 235U mass limit for 100-wt.% enriched contents in the HAC package array is 360 g with a maximum keff + 2 of 0.93743, below the USL of 0.9399.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.1-1. Homogeneous Fissile Mass Size - HDPE Cavity, 100-wt.% 235U Standard HAC Array Fissile keff + 2 for 235U Masses Radius (cm) 355 g 360 g 365 g 370 g 375 g 9.0 0.89801 0.89922 0.90137 0.90410 0.90543 10.0 0.92469 0.92722 0.92978 0.93230 0.93439 10.5 0.93214 0.93483 0.93688 0.94022 0.94322 11.0 0.93396 0.93743 0.94109 0.94395 0.94614 11.5 0.93243 0.93620 0.94031 0.94342 0.94638 12.0 0.92736 0.93141 0.93469 0.93974 0.94210 12.5 0.91976 0.92437 0.92796 0.93199 0.93606 13.5 0.89532 0.90041 0.90388 0.90906 0.91346 Table 6.6.1-2. Homogeneous Fissile Mass Size - Dry Cavity, 100-wt.% 235U Standard HAC Array Fissile keff + 2 for 235U Masses Radius (cm) 355 g 360 g 365 g 370 g 375 g 10.0 0.85233 0.85559 0.85651 0.85895 0.86287 11.0 0.88598 0.88848 0.89274 0.89489 0.89759 11.5 0.89542 0.89797 0.90157 0.90447 0.90916 12.0 0.89898 0.90228 0.90609 0.90940 0.91376 12.5 0.89908 0.90276 0.90759 0.91105 0.91435 13.0 0.89499 0.90010 0.90344 0.90775 0.91172 13.5 0.88795 0.89254 0.89745 0.90100 0.90515 14.5 0.86356 0.86910 0.87416 0.87875 0.88301 Table 6.6.1-3. HDPE Cavity Volume Fraction - 100-wt.% 235U, HDPE Cavity, Standard HAC Array HDPE Inner keff + 2 Cavity VF 0.001 0.88875 0.01 0.89037 0.1 0.89546 0.5 0.91605 1.0 0.93743 6-178

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.1-4. Heterogeneous Particles - 360 g235U, Dry Cavity, 100-wt.% 235U, Standard HAC Array Pitch keff + 2 for Particle Radii1 Ratio1 0.003125 cm 0.00625 cm 0.01250 cm 0.02500 cm 10.5 0.85109 0.83452 0.80477 0.74616 11.0 0.86188 0.84395 0.81017 0.74853 11.5 0.86754 0.84720 0.81067 0.74278 12.0 0.86851 0.84644 0.80789 0.73348 12.5 0.86588 0.84177 0.79932 0.72256 13.0 0.85809 0.83289 0.78873 0.70715 13.5 0.84837 0.82185 0.77402 0.69190 1

Note: Modeled pitch = particle radius

• pitch ratio Table 6.6.1-5. Fissile Mass Position - 100-wt.% 235U, HDPE Cavity, Standard HAC Array Fissile Position keff + 2 All Close 0.93743 Centered Radially 0.93401 Centered Axially 0.92913 All Centered 0.93059 Table 6.6.1-6. Flooding Study Summary - 100-wt.% 235U, HDPE Cavity, HAC Array keff + 2 Interspersed Outer Cavity All Regions Flooding VF Moderation (FLD2) (FLD4)

(FLD3) 0.0 0.93743a 0.001 0.93786 0.93687 0.93756 0.01 0.93722 0.93726 0.93663 0.1 0.93430 0.93724 0.93374 0.5 0.92813 0.93605 0.92749 1.0 0.92594 0.93278 0.92605 a

Note: This is the baseline case.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.1-7. Array Configuration Study - 100-wt.% 235U, HDPE Cavity, Standard HAC Array Array keff + 2 Indexa Three High Four High Five High 1 0.93726 0.93795 0.93780 2 0.93805 0.93727 0.93787 3 0.93810 0.93743b 0.93685 4 0.93775 0.93777 0.93651 5 0.93713 0.93716 0.93623 a

Note: See Section 6.3.4.1.5 for the full array sizes.

b This is the baseline case.

0.96 0.94 0.92 355g keff + 2 360g 0.9 365g 0.88 370g 375g 0.86 360g Dry 0.84 8 10 12 14 16 Fissile Sphere Radius (cm)

Figure 6.6.1-1. Homogeneous Fissile Mass - HDPE Cavity, 100-wt.% 235U, Standard HAC Array 0.92 0.91 0.9 0.89 355g keff + 2 0.88 360g 0.87 365g 0.86 370g 0.85 375g 0.84 9 10 11 12 13 14 15 Fissile Sphere Radius (cm)

Figure 6.6.1-2. Homogeneous Fissile Mass - Dry Cavity, 100-wt.% 235U Standard HAC Array 6-180

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.9 0.85 360g Hom.

Dry keff + 2 0.8 0.003125 cm 0.00625 cm 0.75 0.0125 cm 0.7 0.025 cm 0.65 300 500 700 900 1100 1300 H/U-235 Figure 6.6.1-3. Heterogeneous Particles - 360 g235U, Dry Cavity, 100-wt.% 235U Standard HAC Array 0.95 0.9 0.85 keff + 2 0.8 Het.

0.75 Hom.

0.7 0.65 0 0.005 0.01 0.015 0.02 0.025 0.03 Het. Particle Radius (cm)

Figure 6.6.1-4. Bounding Particle Results - 360 g235U, Dry Cavity, 100-wt.% 235U Standard HAC Array 6-181

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.942 0.937 keff + 2 0.932 Outer Cavity Interspersed All Regions 0.927 0.922 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.1-5. Flooding Study - 360 g235U, HDPE Cavity, 100-wt.% 235U Standard HAC Array 0.947 0.942 keff + 2 0.937 2 high 3 high 4 high 0.932 0.927 0 1 2 3 4 5 6 Array Index Figure 6.6.1-6. Array Configuration Study - HDPE Cavity, 100-wt.% 235U Standard HAC Array 6-182

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.1.2 20-wt.% 235U As shown in Table 6.6.1-8, the 235U mass limit of 445 g determined in the NCT package array evaluation in Section 6.5.1.2 has keff less than the USL of 0.9416 for dry and HDPE cavities. Note that, in this table, the Case Index refers to the varying sphere sizes, as they are different between the two configurations. HDPE is bounding of a dry cavity by a margin of approximately 0.02. In addition, the curves in Figure 6.6.1-7 show that the optimally moderated cases are captured. The HDPE volume fraction study examines various volume fractions of the HDPE inner cavity reflector. This study starts with the bounding HDPE case in Table 6.6.1-8. As shown in Table 6.6.1-9, reducing the volume fraction of HDPE present in the inner cavity results in significant reductions in keff. Therefore, an HDPE cavity volume fraction of 1.0 is bounding for 20-wt.% 235U HAC array. The case with a volume fraction of 0.001 differs from the bounding dry cavity case because the bounding sphere size is different between the dry and HDPE reflector configurations.

The bounding sphere size for the HDPE reflector is equivalent to the sphere size of Case Index 2 for the dry case, showing good agreement with the 0.001 case in the HDPE volume fraction study.

A heterogeneous study is done to determine which configuration is bounding. As shown in Table 6.6.1-10 and Figure 6.6.1-8, the heterogeneous configuration is bounded by the homogeneous configuration for this enrichment. Figure 6.6.1-9 shows that as the particle size decreases and the system approaches homogeneity, the bounding result approaches the homogeneous results.

The fissile position study examines the sensitivity of the system to the position of the fissile spheres. In the homogeneous study, the fissile spheres were placed as close together axially and radially as possible. This study examines additional positions to verify that the default fissile position is bounding. As shown in Table 6.6.1-11, modeling the fissile spheres as close together as possible is bounding of other possible fissile positions. Therefore, the default fissile position is bounding for the 20-wt.% HAC array.

The flooding study examines the effect of various flooding configurations on keff for 20-wt.% 235U.

Note that the Inner Cavity flooding configuration (FLD1) is not examined as the full-density HDPE inner cavity reflector bounds FLD1. As shown in Table 6.6.1-12 and Figure 6.6.1-10, several cases result in increases in keff over the non-flooded case. However, these increases in keff are not statistically significant over the non-flooded case (the baseline result). Therefore, for 20-wt.%

235 U, the baseline configuration is bounding.

The final study examines the sensitivity of the system to the height and configuration of packages in an array. The baseline case models a 3x high array and this study examines 2x and 4x high arrays. In addition, varying rows and columns of packages per array height are examined. As shown in Table 6.6.1-13 and Figure 6.6.1-11, keff of the 2-1 array is marginally higher than the baseline case 3-3 array, but meets the criteria for statistical significance. Therefore, the 2-1 array configuration is the bounding array for the 20-wt.% enriched HAC package array.

As demonstrated, the 235U mass limit of 445 g for 20-wt.% 235U in the HAC package array is acceptable with a maximum keff + 2 of 0.93651, below the USL of 0.9416.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.1-8. Homogeneous Fissile Mass Size wt.% 235U, Standard HAC Array Case keff + 2 Index Dry HDPE 1 0.87597 0.88179 2 0.90608 0.91585 3 0.91346 0.92582 4 0.91671 0.93278 5 0.91680 0.93509 6 0.91338 0.93421 7 0.89610 0.93070 8 -- 0.91581 Table 6.6.1-9. HDPE Cavity Volume Fraction wt.% 235U, Standard HAC Array HDPE Volume keff + 2 Fraction 0.001 0.90606 0.01 0.90659 0.1 0.91018 0.5 0.92088 1.0 0.93509 Table 6.6.1-10. Heterogeneous Fissile Mass Size wt.% 235U, Standard HAC Array keff + 2 for Particle Radii H/235U 0.005 cm 0.015 cm 0.025 cm 0.035 cm 0.045 cm 6.00 0.87321 0.87214 0.86814 0.86081 0.85320 6.25 0.88676 0.88418 0.87838 0.86953 0.86229 6.50 0.89763 0.89243 0.88595 0.87543 0.86697 6.75 0.90180 0.89626 0.88848 0.87824 0.86709 7.00 0.90503 0.89748 0.88753 0.87579 0.86400 7.25 0.90270 0.89622 0.88421 0.87134 0.85780 7.50 0.89821 0.89048 0.87729 0.86308 0.84964 Table 6.6.1-11. Fissile Mass Position wt.% 235U, HDPE Cavity, Standard HAC Array Fissile Position keff + 2 All Close 0.93509 Centered Radially 0.93211 Centered Axially 0.92752 All Centered 0.92877 6-184

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.1-12. Flooding Study Summary wt.% 235U, HDPE Cavity, Standard HAC Array keff + 2 Interspersed Outer Cavity All Regions Flooding VF Moderation (FLD2) (FLD4)

(FLD3) 0.0 0.93509a 0.001 0.93465 0.93584 0.93568 0.01 0.93588 0.93532 0.93553 0.1 0.93231 0.93477 0.93219 0.5 0.92536 0.93300 0.92489 1.0 0.92314 0.93083 0.92402 Note: a This is the baseline case.

Table 6.6.1-13. Array Configuration Study wt.% 235U, HDPE Cavity, Standard HAC Array Array keff + 2 Indexa Three High Four High Five High 1 0.93651 0.93577 0.93481 2 0.93624 0.93603 0.93555 b

3 0.93516 0.93509 0.93546 4 0.93558 0.93590 0.93552 5 0.93612 0.93601 0.93379 a

Note: See Section 6.3.4.1.5 for the full array sizes.

b This is the baseline case.

0.94 0.93 0.92 0.91 keff + 2 Dry 0.9 HDPE 0.89 0.88 0.87 100 300 500 700 900 1100 H/U-235 Figure 6.6.1-7. Homogeneous Fissile Shape wt.% 235U Standard HAC Array 6-185

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.93 0.92 0.91 0.90 Hom. Dry keff + 2 0.89 0.005 cm 0.88 0.015 cm 0.87 0.025 cm 0.86 0.035 cm 0.85 0.045 cm 0.84 300 500 700 900 1100 H/U-235 Figure 6.6.1-8. Heterogeneous Particle Results - Dry Cavity, 20-wt.% 235U Standard HAC Array 0.93 0.92 0.91 0.9 keff + 2 0.89 Het.

0.88 Hom.

0.87 0.86 0.85 0 0.01 0.02 0.03 0.04 0.05 Particle Radius (cm)

Figure 6.6.1-9. Bounding Particle Results - Dry Cavity, 20-wt.% 235U Standard HAC Array 6-186

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.938 0.936 0.934 0.932 keff + 2 0.93 Outer Cavity 0.928 Interspersed All Regions 0.926 0.924 0.922 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.1-10. Flooding Study - HDPE Cavity, 20-wt.% 235U Standard HAC Array 0.945 0.94 keff + 2 0.935 2 high 3 high 4 high 0.93 0.925 0 1 2 3 4 5 6 Array Index Figure 6.6.1-11. Array Configuration Study - HDPE Cavity, 20-wt.% 235U Standard HAC Array 6-187

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.1.3 10-wt.% 235U As shown in Table 6.6.1-14, the 235U mass limit of 505 g determined in the NCT package array evaluation in Section 6.5.1.3 has keff less than the USL of 0.9415 for dry and HDPE cavities. Note that, in this table, the Case Index refers to the varying sphere sizes, as they are different between the two configurations. HDPE is bounding of dry by a margin of approximately 0.01 from HDPE to dry. In addition, the curves in Figure 6.6.1-12 show that the optimally moderated cases are captured. The HDPE volume fraction study examines various volume fractions of the HDPE inner cavity reflector. This study starts with the bounding HDPE case in Table 6.6.1-14. As shown in Table 6.6.1-15, reducing the volume fraction of HDPE present in the inner cavity results in significant reductions in keff. Therefore, an HDPE cavity volume fraction of 1.0 is bounding for 10-wt.% 235U HAC array. The case with a volume fraction of 0.001 differs from the bounding dry cavity case because the bounding sphere size is different between the dry and HDPE reflector configurations. The bounding sphere size for the HDPE reflector is equivalent to the sphere size of Case Index 3 for the dry case, showing good agreement with the 0.001 case in the HDPE volume fraction study.

A heterogeneous study is done to determine which configuration is bounding. As shown in Table 6.6.1-16 and Figure 6.6.1-13, the heterogeneous configuration is bounded by the homogeneous configuration for this enrichment. Figure 6.6.1-14 shows that the bounding particle size is captured and bounded by the homogeneous results.

The fissile position study examines the sensitivity of the system to the position of the fissile spheres. In the homogeneous study, the fissile spheres were placed as close together axially and radially as possible. This study examines additional positions to verify that the default fissile position is bounding. As shown in Table 6.6.1-17, modeling the fissile spheres as close together as possible is bounding of other possible fissile positions. Therefore, the default fissile position is bounding for the 10-wt.% HAC array.

The flooding study examines the effect of various flooding configurations on keff for 10-wt.% 235U.

Note that the Inner Cavity flooding configuration (FLD1) is not examined as the full-density HDPE inner cavity reflector bounds FLD1. As shown in Table 6.6.1-18 and Figure 6.6.1-15 the non-flooded case (the baseline result) is bounding.

The final study examines the sensitivity of the system to the height and configuration of packages in an array. The baseline case models a 3x high array and this study examines 2x and 4x high arrays. In addition, varying rows and columns of packages per array height are examined. As shown in Table 6.6.1-19 and Figure 6.6.1-16, the baseline case (3-3 array) is the bounding array for the 10-wt.% enriched HAC package array.

As demonstrated, the 235U mass limit of 505 g for 10-wt.% 235U in the HAC package array is acceptable with a maximum keff + 2 of 0.92851, below the USL of 0.9415.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.1-14. Homogeneous Fissile Mass Size wt.% 235U, Standard HAC Array Case keff + 2 Index Dry HDPE 1 0.87424 0.88938 2 0.90315 0.91507 3 0.91195 0.92221 4 0.91595 0.92684 5 0.91645 0.92851 6 0.91381 0.92398 7 0.90792 0.91924 8 0.88930 0.90225 Table 6.6.1-15. HDPE Cavity Volume Fraction wt.% 235U, Standard HAC Array HDPE Volume keff + 2 Fraction 0.001 0.91269 0.01 0.91335 0.1 0.91527 0.5 0.91824 1.0 0.92851 Table 6.6.1-16. Heterogeneous Fissile Mass Size wt.% 235U, Standard HAC Array Pitch keff + 2 for Particle Radii Ratio 0.005 cm 0.015 cm 0.025 cm 0.035 cm 0.045 cm 4.75 0.87314 0.87891 0.88008 0.88060 0.87835 5.00 0.89180 0.89637 0.89818 0.89581 0.89490 5.25 0.90226 0.90609 0.90685 0.90663 0.90284 5.50 0.90738 0.91141 0.91092 0.90901 0.90364 5.75 0.90873 0.91096 0.90824 0.90529 0.89984 6.00 0.90325 0.90443 0.90211 0.89697 0.89106 6.25 0.89437 0.89331 0.89048 0.88555 0.87747 Table 6.6.1-17. Fissile Mass Position wt.% 235U, HDPE Cavity, Standard HAC Array Fissile Position keff + 2 All Close 0.92851 Centered Radially 0.92406 Centered Axially 0.91933 All Centered 0.92062 6-189

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.1-18. Flooding Study Summary wt.% 235U, HDPE Cavity, Standard HAC Array keff + 2 Interspersed Outer Cavity All Regions Flooding VF Moderation (FLD2) (FLD4)

(FLD3) 0.0 0.92851a 0.001 0.92658 0.92644 0.92702 0.01 0.92614 0.92710 0.92612 0.1 0.92377 0.92666 0.92295 0.5 0.91741 0.92489 0.91641 1.0 0.91448 0.92268 0.91440 Note: a This is the baseline case.

Table 6.6.1-19. Array Configuration Study wt.% 235U, HDPE Cavity, Standard HAC Array Array keff + 2 Indexa Three High Four High Five High 1 0.92765 0.92645 0.92638 2 0.92734 0.92662 0.92708 b

3 0.92753 0.92851 0.92629 4 0.92705 0.92634 0.92679 5 0.92749 0.92648 0.92476 a

Note: See Section 6.3.4.1.5 for the full array sizes.

b This is the baseline case.

0.94 0.93 0.92 0.91 keff + 2 Dry 0.9 HDPE 0.89 0.88 0.87 200 400 600 800 1000 1200 H/U-235 Figure 6.6.1-12. Homogeneous Fissile Shape wt.% 235U Standard HAC Array 6-190

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.92 0.91 Hom. Dry 0.9 keff + 2 0.005 cm 0.015 cm 0.89 0.025 cm 0.035 cm 0.88 0.045 cm 0.87 200 400 600 800 1000 1200 H/U-235 Figure 6.6.1-13. Heterogeneous Particle Results - Dry Cavity, 10-wt.% 235U Standard HAC Array 0.918 0.914 0.91 keff + 2 0.906 0.902 0.898 0 0.01 0.02 0.03 0.04 0.05 Het. Particle Radius (cm)

Figure 6.6.1-14. Bounding Particle Results - Dry Cavity, 10-wt.% 235U Standard HAC Array 6-191

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.93 0.925 keff + 2 0.92 Outer Cavity Interspersed All Regions 0.915 0.91 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.1-15. Flooding Study - HDPE Cavity, 10-wt.% 235U Standard HAC Array 0.937 0.932 keff + 2 0.927 2 high 3 high 4 high 0.922 0.917 0 1 2 3 4 5 6 Array Index Figure 6.6.1-16. Array Configuration Study - HDPE Cavity, 10-wt.% 235U Standard HAC Array 6-192

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.1.4 5-wt.% 235U As shown in Table 6.6.1-20, the 235U mass limit of 610 g determined in the NCT package array evaluation in Section 6.5.1.4 has keff less than the USL of 0.9417 for dry and HDPE cavities. Note that, in this table, the Case Index refers to the varying sphere sizes, as they are different between the two configurations. As shown, dry is bounding of HDPE by a margin of approximately 0.001.

In addition, the curves in Figure 6.6.1-17 show that the optimally moderated cases are captured.

The HDPE volume fraction study examines various volume fractions of the HDPE cavity reflector.

This study starts with the bounding HDPE case in Table 6.6.1-20. As shown in Table 6.6.1-21, reducing the volume fraction of HDPE results in significant reductions in keff. Therefore, the dry cavity is bounding for 5-wt.% 235U HAC array. The case with a volume fraction of 0.001 differs from the bounding dry cavity case because the bounding sphere size is different between the dry and HDPE reflector configurations. The bounding sphere size for the HDPE reflector is equivalent to the sphere size of Case Index 3 for the dry case, showing good agreement with the 0.001 case in the HDPE volume fraction study.

A heterogeneous study is done to determine which configuration is bounding. As shown in Table 6.6.1-22 and Figure 6.6.1-18, the heterogeneous configuration bounds the homogeneous configuration for this enrichment. Therefore, the starting point for all the following studies is the as-determined bounding heterogeneous pitch/particle size combination.

The fissile position study examines the sensitivity of the system to the position of the particle arrays. In the heterogeneous study, the particle arrays were placed as close together axially and radially as possible. This study examines additional positions to verify that the default position is bounding. As shown in Table 6.6.1-23, modeling the particle arrays as close together as possible is bounding other position. Therefore, the default position is bounding for the 5-wt.% HAC array.

The flooding study examines the effect of various flooding configurations on keff for 5-wt.% 235U.

As shown in Table 6.6.1-24 and Figure 6.6.1-20, the flooding case FLD3_1 is marginally higher than the baseline heterogeneous case and the increase is large enough to meet the criteria to be statistically significant. Therefore, FLD3_1 is bounding for the 5-wt.% 235U HAC array.

The final study examines the sensitivity of the system to the height and configuration of packages in an array. The baseline case models a 3x high array and this study examines 2x and 4x high arrays. In addition, varying rows and columns of packages per array height are examined. As shown in Table 6.6.1-25 and Figure 6.6.1-21, a 3x high array is clearly bounding, with keff of the 3-4 array marginally higher than the baseline case 3-3 array. However, this increase is not statistically significant. Therefore, the baseline 3-3 array is bounding for the 5-wt.% enriched HAC package array.

As demonstrated, the 235U mass limit of 610 g for 5-wt.% 235U in the HAC package array is acceptable with a maximum keff + 2 of 0.91936, below the USL of 0.9417.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.1-20. Homogeneous Fissile Mass Size wt.% 235U, Standard HAC Array Case keff + 2 Index Dry HDPE 1 0.88965 0.88804 2 0.89919 0.89835 3 0.90697 0.90515 4 0.91032 0.90871 5 0.91227 0.91096 6 0.90863 0.90878 7 0.90298 0.90479 8 0.88682 0.89080 Table 6.6.1-21. HDPE Cavity Volume Fraction wt.% 235U, HDPE Cavity, Standard HAC Array HDPE Inner keff + 2 Cavity VF 0.001 0.90795 0.01 0.90845 0.1 0.90988 0.5 0.90699 1.0 0.91096 Table 6.6.1-22. Heterogeneous Fissile Mass Size wt.% 235U, Standard HAC Array keff + 2 for Particle Radii 235 H/ U 0.0125 cm 0.025 cm 0.050 cm 0.075 cm 0.100 cm 400 0.86851 0.87472 0.87984 0.88419 0.88170 492 0.89351 0.89897 0.90467 0.90520 0.90326 597 0.90726 0.91366 0.91650 0.91595 0.91136 716 0.91092 0.91611 0.91748 0.91578 0.90925 848 0.90696 0.91182 0.91011 0.90719 0.89857 995 0.89588 0.89928 0.89732 0.89132 0.88176 Table 6.6.1-23. Fissile Mass Position wt.% 235U, HDPE Cavity, Standard HAC Array Fissile Position keff + 2 All Close 0.91748 Centered Radially 0.91538 Centered Axially 0.89898 All Centered 0.89665 6-194

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.1-24. Flooding Study Summary wt.% 235U, HDPE Cavity, Standard HAC Array keff + 2 Interspersed Inner Cavity Outer Cavity All Regions Flooding VF Moderation (FLD1) (FLD2) (FLD4)

(FLD3) a 0.0 0.91748 0.001 0.91814 0.91881 0.91936 0.91839 0.01 0.91909 0.91687 0.91819 0.91678 0.1 0.91777 0.89561 0.91469 0.89444 0.5 0.91295 0.85423 0.89505 0.87940 1.0 0.91230 0.84318 0.88014 0.88839 Note: a This is the baseline case.

Table 6.6.1-25. Array Configuration Study wt.% 235U, HDPE Cavity, Standard HAC Array Array keff + 2 Indexa Two High Three High Four High 1 0.91431 0.91393 0.91443 2 0.91560 0.91746 0.91858 3 0.91624 0.91936b 0.91818 4 0.91621 0.92019 0.91388 5 0.91486 0.91666 0.90309 Note: a See Section 6.3.4.1.5 for the full array sizes.

b This is the baseline case.

0.93 0.92 0.91 keff + 2 0.9 Dry 0.89 HDPE 0.88 0.87 200 400 600 800 1000 1200 H/U-235 Figure 6.6.1-17. Homogeneous Fissile Shape wt.% 235U Standard HAC Array 6-195

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.93 0.92 0.91 610g Hom.

0.9 keff + 2 0.0125 cm 0.89 0.025 cm 0.05 cm 0.88 0.075 cm 0.87 0.1 cm 0.86 200 400 600 800 1000 1200 H/U-235 Figure 6.6.1-18. Heterogeneous Particle Results - Dry Cavity, 5-wt.% 235U Standard HAC Array 0.925 0.92 keff + 2 0.915 0.91 0.905 0 0.02 0.04 0.06 0.08 0.1 0.12 Het. Particle Radius (cm)

Figure 6.6.1-19. Bounding Particle Results - Dry Cavity, 5-wt.% 235U Standard HAC Array 6-196

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.93 0.92 0.91 0.9 0.89 keff + 2 Inner Cavity 0.88 Outer Cavity 0.87 Interspersed 0.86 All Regions 0.85 0.84 0.83 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.1-20. Flooding Study wt.% 235U Standard HAC Array 0.922 0.918 0.914 keff + 2 2 high 0.91 3 high 4 high 0.906 0.902 0 1 2 3 4 5 6 Array Index Figure 6.6.1-21. Array Configuration Study wt.% 235U Standard HAC Array 6-197

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.1.5 1.25-wt.% 235U As shown in Table 6.6.1-26, the 235U mass limit of 1650 g determined in the NCT package array evaluation in Section 6.5.1.5 has keff less than the USL of 0.9423 for dry and HDPE cavities. A dry cavity is bounding of HDPE by a margin of approximately 0.001. In addition, the curves in Figure 6.6.1-22 show that the optimally moderated cases are captured. The HDPE volume fraction study examines various volume fractions of the HDPE cavity reflector. This study starts with the bounding HDPE case in Table 6.6.1-26. As shown in Table 6.6.1-27, reducing the volume fraction of HDPE present in the inner cavity results in increased in keff. However, the maximum keff increase of 0.87487 for HDPE VF of 0.001 is bounded by the dry cavity with maximum keff of 0.87528. Therefore, the dry cavity is bounding for 1.25-wt.% 235U HAC array.

A heterogeneous study is done to determine which configuration is bounding. As shown in Table 6.6.1-28 and Figure 6.6.1-23, the heterogeneous configuration bounds the homogeneous configuration for this enrichment. Therefore, the starting point for all the following studies is the as-determined bounding heterogeneous pitch/particle size combination.

The fissile position study examines the sensitivity of the system to the position of the particle arrays. In the heterogeneous study, the particle arrays were placed as close together axially and radially as possible. This study examines additional positions to verify that the default position is bounding. As shown in Table 6.6.1-29, modeling the particle arrays as close together as possible is bounding of other positions. Therefore, the default position is bounding for the 1.25-wt.% HAC array.

The flooding study examines the effect of flooding on keff for 1.25-wt.% 235U. As shown in Table 6.6.1-30 and Figure 6.6.1-25, several cases result in increases in keff over the unflooded case.

However, these increases in keff are not statistically significant over the unflooded baseline.

Therefore, the baseline configuration is bounding for 1.25-wt.% 235U.

The final study examines the sensitivity of the system to the height and configuration of packages in an array. The baseline case models a 3x high array and this study examines 2x and 4x high arrays. In addition, varying rows and columns of packages per array height are examined. As shown in Table 6.6.1-31 and Figure 6.6.1-26, keff of the 3-4 array is marginally higher than the baseline 3-3 array case, but enough to meet the criteria to be statistically significant. Therefore, the 3-4 array is bounding for the 1.25-wt.% enriched HAC package array. Note that the 5-2 array has the largest keff + 2, however, its keff is not greater than 2 over the baseline 3-3 array keff.

This is because the 5-2 array case has a slightly higher value for s than the other cases, making keff+2s for this case slightly higher, but still well below the USL.

As demonstrated, the 235U mass limit of 1650 g for 1.25-wt.% 235U in the HAC package array is acceptable with a maximum keff + 2 of 0.92750, below the USL of 0.9423.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.1-26. Homogeneous Fissile Mass Size - 1.25-wt.% 235U, Standard HAC Array keff + 2 235 H/ U Dry HDPE 453 0.86151 0.85064 568 0.87469 0.86350 684 0.87528 0.86520 799 0.86892 0.86052 915 0.85799 0.85097 1030 0.84538 0.84019 Table 6.6.1-27. HDPE Cavity Volume Fraction - 1.25-wt.% 235U, HDPE Cavity, Standard HAC Array HDPE Inner keff + 2 Cavity VF 0.001 0.87487 0.01 0.87490 0.1 0.87355 0.5 0.86730 1.0 0.86520 Table 6.6.1-28. Heterogeneous Fissile Mass Size - 1.25-wt.% 235U, Standard HAC Array keff + 2 for Particle Radii 235 H/ U 0.20 cm 0.30 cm 0.35 cm 0.40 cm 0.50 cm 400 0.91084 0.91978 0.92081 0.92065 0.91935 492 0.91568 0.92338 0.92395 0.92338 0.92215 597 0.91967 0.92539 0.92544 0.92529 0.92108 716 0.92146 0.92675 0.92667 0.92506 0.92039 848 0.92292 0.92608 0.92598 0.92466 0.91859 995 0.92281 0.92596 0.92553 0.92162 0.91551 0.92001 0.92262 0.92065 0.91768 0.90886 Table 6.6.1-29. Fissile Mass Position - 1.25-wt.% 235U, HDPE Cavity, Standard HAC Array Fissile Position keff + 2 All Close 0.92675 Centered Radially 0.92605 Centered Axially 0.91556 All Centered 0.91511 6-199

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.1-30. Flooding Study Summary - 1.25-wt.% 235U, HDPE Cavity, Standard HAC Array keff + 2 Interspersed Inner Cavity Outer Cavity All Regions Flooding VF Moderation (FLD1) (FLD2) (FLD4)

(FLD3) a 0.0 0.92675 0.001 0.92629 0.92677 0.92696 0.92663 0.01 0.92728 0.92445 0.92728 0.92461 0.1 0.92644 0.90756 0.92319 0.90434 0.5 0.91974 0.86496 0.90645 0.86811 1.0 0.91429 0.85312 0.89157 0.86559 a

Note: This is the baseline case.

Table 6.6.1-31. Array Configuration Study - 1.25-wt.% 235U, HDPE Cavity, Standard HAC Array Array keff + 2 Indexa Two High Three High Four High 1 0.92256 0.92298 0.92381 2 0.92304 0.92633 0.92757 b

3 0.92365 0.92675 0.92736 4 0.92371 0.92750 0.92306 5 0.92352 0.92563 0.91479 a

Note: See Section 6.3.4.1.5 for the full array sizes.

b This is the baseline case.

0.88 0.875 0.87 0.865 keff + 2 0.86 0.855 Dry 0.85 HDPE 0.845 0.84 0.835 300 600 900 1200 H/U-235 Figure 6.6.1-22. Homogeneous Fissile Shape - 1.25-wt.% 235U Standard HAC Array 6-200

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.94 0.93 0.92 0.91 0.2 cm 0.9 keff + 2 0.3 cm 0.89 0.35 cm 0.88 0.4 cm 0.87 0.5 cm 0.86 Hom. Dry 0.85 0.84 350 550 750 950 1150 H/U-235 Figure 6.6.1-23. Heterogeneous Particle Results - Dry Cavity, 1.25-wt.% 235U Standard HAC Array 0.935 0.93 keff + 2 0.925 0.92 0.915 0.1 0.2 0.3 0.4 0.5 0.6 Het. Particle Radius (cm)

Figure 6.6.1-24. Bounding Particle Results - Dry Cavity, 1.25-wt.% 235U Standard HAC Array 6-201

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.94 0.93 0.92 0.91 0.9 keff + 2 Inner Cavity 0.89 Outer Cavity 0.88 Interspersed 0.87 All Regions 0.86 0.85 0.84 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.1-25. Flooding Study -1.25-wt.% 235U Standard HAC Array 0.932 0.927 keff + 2 0.922 2 high 3 high 4 high 0.917 0.912 0 1 2 3 4 5 6 Array Index Figure 6.6.1-26. Array Configuration Study - 1.25-wt.% 235U Standard HAC Array 6-202

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2 Hydrogen-Limited Contents Including TRISO Fuels For the HAC package array evaluation of hydrogen-limited contents, the fissile spheres are modeled as close as possible to each other in the radial and axial directions to maximize cross-talk between fissile regions. The arrangement of the spheres for the HAC package arrays is shown in Figure 6.3.4-3. All HAC package arrays model at least 12 inches of full-density water reflection in all directions. Presented with each HAC package array analysis is a flooding study analyzing incremental flooding of the void regions in the model for three separate regions and all regions at once, for four total cases. These cases are shown in Figure 6.3.4-4 with FLD1 - Cavity Region, FLD2 - Outer Packaging, FLD3 - Interspersed, and FLD4 - All Regions.

For the 20-wt.% 235U HAC package array evaluation of hydrogen-limited contents, two arrays are analyzed for CSI=0.7 and CSI=1.0. In each case, the fissile spheres are modeled as close as possible to each other in the radial and axial directions to maximize cross-talk between fissile regions. The arrangement of the spheres for the CSI=1.0 HAC package array case is shown in Figure 6.3.4-3. The arrangement of spheres for the CSI=0.7 case is the same, but with additional packages in the array.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.1 100-wt.% 235U Results 6.6.2.1.1 Fissile Sphere Size Variation The results for the 100-wt.% 235U HAC package array evaluation are shown in Table 6.6.2-1 and Figure 6.6.2-1. The results show that the maximum fissile mass below the USL is 515 g235U.

Thus, for a fissile mass of 515 g235U, this HAC package array evaluation demonstrates subcriticality for a 2N array of packages under HAC with 100-wt.% 235U.

Table 6.6.2-1. 100-wt.% 235U Hydrogen-Limited Content HAC Array Results Radius keff + 2 for Fissile Spheres (cm) 510 g 515 g 520 g 525 g 530 g 13.5 0.92642 0.92782 0.93007 0.93296 0.93558 14 0.93084 0.93290 0.93547 0.93848 0.94049 14.25 0.93269 0.93474 0.93786 0.93957 0.94247 14.5 0.93264 0.93502 0.93859 0.94071 0.94458 14.75 0.93227 0.93461 0.93828 0.94027 0.94263 15 0.93161 0.93384 0.93809 0.94056 0.94428 15.25 0.93084 0.93353 0.93678 0.93923 0.94237 15.5 0.92937 0.93070 0.93411 0.93835 0.94059 16 0.92194 0.92531 0.92859 0.93282 0.93463 0.95 0.945 0.94 510 g keff + 2 0.935 515 g 520 g 0.93 525 g 0.925 530 g 0.92 13 13.5 14 14.5 15 15.5 16 16.5 Fissile Sphere Radius (cm)

Figure 6.6.2-1. 100-wt.% 235U Hydrogen-Limited Content HAC Array Results 6-204

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.1.2 Flooding Study The results for the HAC package array flooding study with 100-wt.% 235U and 515 g235U are shown in Table 6.6.2-2 and Figure 6.6.2-2. The results of this study show that flooding in any region other than the package cavity only results in a reduction in keff. Several flooding cases result in slight increases in keff, but these increases are not significant and do not result in the maximum keff value exceeding the USL.

Table 6.6.2-2. 100-wt.% 235U Hydrogen-Limited Content HAC Array - Flooding Results keff + 2 for Flooding Configurations Flooding Interspersed VF Inner Cavity Outer Cavity All Regions Moderation (FLD1) (FLD2) (FLD4)

(FLD3) 0.0001 0.93528 0.93586 0.93564 0.93502 A 0.001 0.93529 0.93509 0.93575 0.93559 0.01 0.93574 0.93208 0.93552 0.93193 0.1 0.93388 0.89683 0.92869 0.89515 0.5 0.92509 0.83085 0.89434 0.87724 1.0 0.92508 0.81191 0.86685 0.89934 A

Note: This is the baseline case 0.96 0.94 0.92 0.9 k-eff + 2 Inner Cavity 0.88 Outer Cavity 0.86 Interspersed 0.84 All Regions 0.82 0.8 0.0001 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.2-2. 100-wt.% 235U Hydrogen-Limited Content HAC Array - Flooding Results 6-205

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.1.3 Heterogeneous Particle Array Study This section evaluates a heterogeneous array of spherical uranium particles suspended in a homogeneous mixture of water and 1 lb HDPE to verify that the homogeneous mixtures analyzed in the base HAC package array and single package analyses are bounding. The results for the HAC package array heterogeneous effects study are shown in Table 6.6.2-3 and Figure 6.6.2-3.

The results show that a homogeneous sphere is bounding of the heterogeneous arrangement.

As the particle size is reduced and the analyzed geometry approaches a homogenized mixture, the calculated values for keff approach those calculated for the homogeneous mixture from the base analysis but are still bounded.

Table 6.6.2-3. 100-wt.% 235U Heterogeneous Effects HAC Array Study Results Pitch keff + 2 for Particle Size (cm)

H/235U Ratio 0.003175 0.00625 0.0125 0.025 11 439 0.88094 0.86617 0.83537 0.77551 11.5 501 0.89185 0.87474 0.84096 0.77601 12 569 0.89767 0.87893 0.84294 0.77227 12.5 642 0.90015 0.88056 0.83874 0.76503 13 722 0.89673 0.87584 0.83383 0.75592 13.5 808 0.89122 0.86976 0.82494 0.74270 0.94 0.92 0.9 0.88 0.86 0.003175 cm k-eff + 2s 0.84 0.00625 cm 0.82 0.0125 cm 0.8 0.025 cm 0.78 Hom.

0.76 0.74 400 500 600 700 800 900 H/U-235 Figure 6.6.2-3. 100-wt.% 235U Heterogeneous Effects HAC Array Study Results 6-206

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.2 20-wt.% 235U Results 6.6.2.2.1 Fissile Sphere Size Variation The results for the HAC package array evaluation with CSI=0.7 are shown in Table 6.6.2-4 and Figure 6.6.2-4. The results show that the maximum fissile mass below the USL is 605 g235U.

Thus, for a fissile mass of 605 g235U, this HAC package array evaluation demonstrates subcriticality for a 2N array of packages under HAC with CSI=0.7.

The results for the HAC package array evaluation with CSI=1.0 are shown in Table 6.6.2-5 and Figure 6.6.2-5. The results show that the maximum fissile mass below the USL is 640 g235U.

However, based on the flooding study documented in Section 6.6.2.2.2, the limiting fissile mass is set at 635 g235U so that the peak keff value in a bounding flooding configuration does not exceed the USL. Thus, for a fissile mass of 635 g235U, this HAC package array evaluation demonstrates subcriticality for a 2N array of packages under HAC with CSI=1.0.

Table 6.6.2-4. 20-wt.% 235U Hydrogen-Limited Content HAC Array (CSI=0.7) Results Radius keff + 2 for Fissile Spheres (cm) 600 g 605 g 610 g 615 g 620 g 14.5 0.92821 0.92984 0.93268 0.93372 0.93547 15 0.93196 0.93390 0.93640 0.93938 0.94013 15.25 0.93385 0.93535 0.93922 0.94018 0.94194 15.5 0.93379 0.93632 0.93805 0.94144 0.94240 15.75 0.93467 0.93645 0.93970 0.94092 0.94311 16 0.93380 0.93585 0.93882 0.94020 0.94323 16.5 0.93096 0.93306 0.93588 0.93739 0.94017 17 0.92486 0.92832 0.92945 0.93157 0.93447 Table 6.6.2-5. 20-wt.% 235U Hydrogen-Limited Content HAC Array (CSI=1.0) Results Radius keff + 2 for Fissile Spheres (cm) 630 g 635 g 640 g 645 g 650 g 14.5 0.92449 0.92642 0.92720 0.92915 0.92951 15 0.92904 0.93190 0.93338 0.93455 0.93675 15.5 0.93168 0.93465 0.93739 0.93871 0.94122 15.75 0.93308 0.93523 0.93714 0.93948 0.94101 16 0.93229 0.93568 0.93790 0.93921 0.94110 16.25 0.93296 0.93483 0.93719 0.93908 0.94125 16.5 0.93138 0.93293 0.93622 0.93799 0.93985 17 0.92802 0.92985 0.93198 0.93400 0.93643 6-207

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.945 0.94 600 g k-eff + 2 0.935 605 g 610 g 0.93 615 g 0.925 620 g 0.92 14 14.5 15 15.5 16 16.5 17 17.5 Fissile Sphere Radius (cm)

Figure 6.6.2-4. 20-wt.% 235U Hydrogen-Limited Content HAC Array (CSI=0.7) Results 0.95 0.945 0.94 630 g k-eff + 2 0.935 635 g 640 g 0.93 645 g 0.925 650 g 0.92 14 14.5 15 15.5 16 16.5 17 17.5 Fissile Sphere Radius (cm)

Figure 6.6.2-5. 20-wt.% 235U Hydrogen-Limited Content HAC Array (CSI=1.0) Results 6-208

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.2.2 Flooding Study The results for the HAC package array flooding study with CSI=0.7 and 605 g235U are shown in Table 6.6.2-6 and Figure 6.6.2-6. The results of this study show that flooding in any region other than the package cavity only results in a reduction in keff. Flooding the void space in the package cavity with water at a volume fraction of 0.01 results in a very slight increase in keff, but this increase is not significant and does not result in the maximum keff value exceeding the USL.

The results for the HAC package array flooding study with CSI=1.0 are shown in Table 6.6.2-7 and Figure 6.6.2-7. Similar to the CSI=0.7 result, the results of this study show that flooding in any region other than the package cavity only results in a reduction in keff. However, flooding the void space in the package cavity with water at a volume fraction of 0.1 results in a very slight increase in keff. For 640 g235U, this increase results in the maximum keff value exceeding the USL.

With the fissile mass reduced to 635 g235U, there is still an increase in keff with water at a volume fraction of 0.1 in the cavity, however the peak keff value remains under the USL. Thus, the fissile mass limit for a HAC package array with CSI=1.0 is set at 635 g235U.

Table 6.6.2-6. 20-wt.% 235U Hydrogen-Limited Content HAC Array (CSI=0.7) - Flooding Results keff + 2 for Flooding Configurations Flooding Interspersed VF Inner Cavity Outer Cavity All Regions Moderation (FLD1) (FLD2) (FLD4)

(FLD3) 0.0001 0.93596 0.93615 0.93694 0.93645 A 0.001 0.93663 0.93585 0.93679 0.93549 0.01 0.93736 0.93413 0.93705 0.93327 0.1 0.93567 0.89989 0.93103 0.89642 0.5 0.92228 0.83558 0.89886 0.86988 1.0 0.91632 0.81767 0.87231 0.88610 A

Note: This is the baseline case Table 6.6.2-7. 20-wt.% 235U Hydrogen-Limited Content HAC Array (CSI=1.0) - Flooding Results keff + 2 for Flooding Configurations Flooding 635 g235U 640 g235U VF Interspersed Inner Cavity Inner Cavity Outer Cavity All Regions Moderation (FLD1) (FLD1) (FLD2) (FLD4)

(FLD3) 0.0001 0.93536 0.93761 0.93837 0.93820 0.93790 A 0.001 0.93572 0.93735 0.93725 0.93763 0.93751 0.01 0.93683 0.93869 0.93500 0.93588 0.93610 0.1 0.93765 0.94082 0.90798 0.93252 0.90669 0.5 0.93004 0.93363 0.84771 0.90605 0.88092 1.0 0.92418 0.92704 0.83213 0.88256 0.89727 Note: A This is the baseline case 6-209

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.96 0.94 0.92 0.9 k-eff + 2 Inner Cavity 0.88 Outer Cavity 0.86 Interspersed 0.84 All Regions 0.82 0.8 0.0001 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.2-6. 20-wt.% 235U Hydrogen-Limited HAC Array (CSI=0.7) - 605 g235U Flooding Results 0.96 0.94 0.92 k-eff + 2s 0.9 Inner Cavity 0.88 Outer Cavity Interspersed 0.86 All Regions 0.84 0.82 0.0001 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.2-7. 20-wt.% 235U Hydrogen-Limited HAC Array (CSI=1.0) - 640 g235U Flooding Results 6-210

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.2.3 Heterogeneous Particle Array Study This section evaluates a heterogeneous array of spherical uranium particles suspended in a homogeneous mixture of water and 1 lb HDPE to verify that the homogeneous mixtures analyzed in the base HAC package array and single package analyses are bounding. This study is only conducted for the CSI=0.7 case, but the same conclusion can be applied to the CSI=1.0 case as well. The results for the HAC package array heterogeneous effects study are shown in Table 6.6.2-8 and Figure 6.6.2-8. The results show that a homogeneous sphere is bounding of the heterogeneous arrangement. As the particle size is reduced and the analyzed geometry approaches a homogenized mixture, the calculated values for keff approach those calculated for the homogeneous mixture from the base analysis but are still bounded.

Table 6.6.2-8. 20-wt.% 235U Heterogeneous Effects HAC Array Study (CSI=0.7) Results Pitch keff + 2 for Particle Size H/235U Ratio 0.00625 cm 0.0125 cm 0.025 cm 0.05 cm 0.1 cm 6.75 500 0.91427 0.91202 0.90343 0.88037 0.82663 7 558 0.91972 0.91770 0.90797 0.88303 0.82452 7.25 620 0.92440 0.92134 0.90976 0.88172 0.82085 7.5 687 0.92552 0.91980 0.90873 0.87775 0.81099 7.75 758 0.92248 0.91783 0.90354 0.87130 0.80088 8 834 0.91767 0.91281 0.89595 0.86214 0.78925 8.25 915 0.91192 0.90627 0.88809 0.85104 0.77403 0.95 0.93 0.91 0.89 0.00625 cm 0.87 k-eff + 2s 0.0125 cm 0.85 0.025 cm 0.83 0.05 cm 0.81 0.1 cm 0.79 Homog.

0.77 0.75 400 500 600 700 800 900 1000 H/U-235 Figure 6.6.2-8. 20-wt.% 235U Heterogeneous Effects HAC Array Study (CSI=0.7) Results 6-211

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.3 10-wt.% 235U Results 6.6.2.3.1 Fissile Sphere Size Variation The results for the 10-wt.% 235U HAC package array evaluation are shown in Table 6.6.2-9 and Figure 6.6.2-9. The results show that the maximum fissile mass below the USL is 685 g235U.

Thus, for a fissile mass of 685 g235U, this HAC package array evaluation demonstrates subcriticality for a 2N array of packages under HAC with 10-wt.% 235U.

Table 6.6.2-9. 10-wt.% 235U Hydrogen-Limited Content HAC Array Results Radius keff + 2 for Fissile Spheres (cm) 675 g 680 g 685 g 690 g 695 g 15 0.92540 0.92754 0.92820 0.93077 0.93239 15.5 0.93063 0.93309 0.93435 0.93564 0.93772 15.75 0.93274 0.93442 0.93592 0.93640 0.93933 16 0.93280 0.93543 0.93717 0.93822 0.94097 16.25 0.93349 0.93541 0.93688 0.93925 0.94132 16.5 0.93356 0.93479 0.93665 0.94006 0.94076 17 0.93035 0.93292 0.93461 0.93676 0.93920 17.5 0.92660 0.92870 0.93078 0.93182 0.93486 0.95 0.945 0.94 675 g k-eff + 2 0.935 680 g 685 g 0.93 690 g 0.925 695 g 0.92 14.5 15 15.5 16 16.5 17 17.5 18 Fissile Sphere Radius (cm)

Figure 6.6.2-9. 10-wt.% 235U Hydrogen-Limited Content HAC Array Results 6-212

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.3.2 Flooding Study The results for the HAC package array flooding study with 10-wt.% 235U and 685 g235U are shown in Table 6.6.2-10 and Figure 6.6.2-10. The results of this study show that flooding the inner cavity with 0.01 VF water results in a marginal yet significant increase in keff. Therefore, this flooding configuration is bounding for 10-wt.% 235U hydrogen-limited content in the HAC array evaluation.

Table 6.6.2-10. 10-wt.% 235U Hydrogen-Limited Content HAC Array - Flooding Results keff + 2 for Flooding Configurations Flooding Interspersed VF Inner Cavity Outer Cavity All Regions Moderation (FLD1) (FLD2) (FLD4)

(FLD3) 0.0001 0.93630 0.93683 0.93705 0.93717A 0.001 0.93756 0.93645 0.93701 0.93700 0.01 0.93860 0.93488 0.93669 0.93440 0.1 0.93590 0.90098 0.93037 0.89904 0.5 0.92352 0.83663 0.89925 0.86984 1.0 0.91510 0.81838 0.87391 0.88478 B

Note: This is the baseline case 0.96 0.94 0.92 0.9 k-eff + 2 Inner Cavity 0.88 Outer Cavity 0.86 Interspersed 0.84 All Regions 0.82 0.8 0.0001 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.2-10. 10-wt.% 235U Hydrogen-Limited Content HAC Array - Flooding Results 6-213

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.3.3 Heterogeneous Particle Array Study This section evaluates a heterogeneous array of spherical uranium particles suspended in a homogeneous mixture of water and 1 lb HDPE to verify that the homogeneous mixtures analyzed in the base HAC package array and single package analyses are bounding. The results for the HAC package array heterogeneous effects study are shown in Table 6.6.2-11 and Figure 6.6.2-11. The results show that a homogeneous sphere is bounding of the heterogeneous arrangement. As the particle size is reduced and the analyzed geometry approaches a homogenized mixture, the calculated values for keff approach those calculated for the homogeneous mixture from the base analysis but are still bounded.

Table 6.6.2-11. 10-wt.% 235U Heterogeneous Effects HAC Array Study Results Pitch keff + 2 for Particle Size (cm)

H/235U Ratio 0.00625 0.0125 0.025 0.05 5.625 572 0.92955 0.93212 0.93230 0.92400 5.75 612 0.93213 0.93391 0.93344 0.92557 5.875 653 0.93313 0.93507 0.93405 0.92533 6 696 0.93289 0.93476 0.93330 0.92291 6.125 741 0.93183 0.93434 0.93223 0.91951 6.25 788 0.92920 0.93126 0.92921 0.91599 0.94 0.935 0.93 0.00625 cm k-eff + 2s 0.0125 cm 0.925 0.025 cm 0.05 cm 0.92 Hom.

0.915 500 600 700 800 900 H/U-235 Figure 6.6.2-11. 10-wt.% 235U Heterogeneous Effects HAC Array Study Results 6-214

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.4 5-wt.% 235U Results 6.6.2.4.1 Fissile Sphere Size Variation The results for the 5-wt.% 235U HAC package array evaluation are shown in Table 6.6.2-9 and Figure 6.6.2-9. The results show that the maximum fissile mass below the USL is 840 g235U for a homogeneous configuration.

Table 6.6.2-12. 5-wt.% 235U Hydrogen-Limited Content HAC Array Results Radius keff + 2 for Fissile Spheres (cm) 825 g 830 g 835 g 840 g 845 g 16 0.92620 0.92636 0.92787 0.92885 0.92980 16.5 0.93066 0.93129 0.93266 0.93441 0.93514 17 0.93293 0.93462 0.93638 0.93749 0.93893 17.25 0.93336 0.93543 0.93812 0.93792 0.93950 17.5 0.93427 0.93492 0.93678 0.93903 0.93982 17.75 0.93290 0.93449 0.93578 0.93734 0.94057 18 0.93213 0.93295 0.93485 0.93726 0.93792 18.5 0.92885 0.93065 0.93209 0.93375 0.93487 0.95 0.945 0.94 825 g k-eff + 2 0.935 830 g 835 g 0.93 840 g 0.925 845 g 0.92 15.5 16 16.5 17 17.5 18 18.5 19 Fissile Sphere Radius (cm)

Figure 6.6.2-12. 5-wt.% 235U Hydrogen-Limited Content HAC Array Results 6-215

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.4.2 Heterogeneous Particle Array Study This section evaluates a heterogeneous array of spherical uranium particles suspended in a homogeneous mixture of water and 1 lb HDPE to verify that the homogeneous mixtures analyzed in the base HAC package array and single package analyses are bounding. The results for the HAC package array heterogeneous effects study are shown in Table 6.6.2-13. The results show that a heterogeneous arrangement is bounding of the homogeneous sphere. Also, 840 g235U results in keff above the USL. Due to the heterogeneous effects, the fissile mass must be reduced for keff to be less than the USL. As shown in Table 6.6.2-14 and Figure 6.6.2-13, reducing the fissile mass to 800 g235U results in keff below the USL for the heterogeneous arrangement. Also shown is the bounding homogeneous H/235U curve for 840 g235U. Therefore, 800 g235U in a heterogeneous arrangement is the bounding configuration for 5-wt.% 235U hydrogen-limited contents.

Table 6.6.2-13. 5-wt.% 235U 840 g235U Heterogeneous Effects HAC Array Study Results Pitch keff + 2 for Particle Size (cm)

H/235U Ratio 0.0125 0.025 0.05 0.1 0.2 4.375 523 0.93173 0.93724 0.94460 0.93995 0.91889 4.5 570 0.93659 0.94251 0.94601 0.94233 0.91815 4.625 623 0.94029 0.94437 0.94847 0.94271 0.91542 4.75 676 0.93928 0.94509 0.94846 0.94108 0.91070 4.875 733 0.94021 0.94325 0.94611 0.93786 0.90410 5.0 793 0.93620 0.94123 0.94158 0.93209 0.89635 Table 6.6.2-14. 5-wt.% 235U 800 g235U Heterogeneous Effects HAC Array Study Results Pitch keff + 2 for Particle Size (cm)

H/235U Ratio 0.0125 0.025 0.05 0.1 0.2 4.375 523 0.91965 0.92534 0.93050 0.92805 0.90710 4.5 570 0.92399 0.92928 0.93479 0.92987 0.90629 4.625 623 0.92694 0.93261 0.93672 0.93040 0.90385 4.75 676 0.92879 0.93289 0.93626 0.92911 0.89873 4.875 733 0.92850 0.93289 0.93468 0.92530 0.89194 5.0 793 0.92628 0.92937 0.93013 0.92175 0.88535 6-216

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.94 0.93 0.0125 cm k-eff + 2s 0.025 cm 0.92 0.05 cm 0.91 0.1 cm 0.2 cm 0.9 Hom. 840gU235 0.89 450 550 650 750 850 H/U-235 Figure 6.6.2-13. 5-wt.% 235U 800 g235U Heterogeneous Effects HAC Array Study Results 6-217

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.2.4.3 Flooding Study The results for the HAC package array flooding study with 5-wt.% 235U and 800 g235U are shown in Table 6.6.2-15 and Figure 6.6.2-14. The results of this study show that flooding the interspersed region with 0.0001 VF water results in a marginal increase in keff. However, this increase is not significant. Therefore, the baseline flooding configuration of 0.0001 VF water in all regions is bounding for 5-wt.% 235U hydrogen-limited content in the HAC array evaluation.

Table 6.6.2-15. 5-wt.% 235U Hydrogen-Limited Content HAC Array - Flooding Results keff + 2 for Flooding Configurations Flooding Interspersed VF Inner Cavity Outer Cavity All Regions Moderation (FLD1) (FLD2) (FLD4)

(FLD3) 0.0001 0.93600 0.93612 0.93696 0.93672A 0.001 0.93626 0.93587 0.93619 0.93612 0.01 0.93663 0.93428 0.93626 0.93317 0.1 0.92927 0.90342 0.93066 0.90000 0.5 0.90463 0.84053 0.89999 0.86558 1.0 0.89515 0.82069 0.87683 0.87147 A

Note: This is the bounding heterogeneous case.

0.96 0.94 0.92 0.9 k-eff + 2 Inner Cavity 0.88 Outer Cavity 0.86 Interspersed 0.84 All Regions 0.82 0.8 0.0001 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.2-14. 5-wt.% 235U Hydrogen-Limited Content HAC Array - Flooding Results 6-218

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.3 5-inch Pipe Table 6.6.3-1 summarizes the results of the Package Array Evaluation under HAC. As shown in Table 6.6.3-1, none of the HAC configurations resulted in values of keff + 2 that came within 0.04 of the USL because the U-235 mass limits determined in this calculation were all derived in the NCT evaluation, which is bounding of HAC. The large margins in keff + 2 with their respective USLs for all of the HAC configurations confirms the subcriticality of the U-235 mass limits determined in the NCT array evaluation when analyzed in the HAC array evaluation.

Table 6.6.3-1. Summary of Limiting Cases for HAC Package Array Evaluation Number of U-235 U-235 Fill Case Packages keff + 2 USL Enrichment Mass (g) Percent (2N)

VP-55_5IP_HAC_100WT_3X105_VF095 100 695 105 95 0.89434 0.9399 VP-55_5IP_HAC_20WT_3X105_VF100 20 1215 105 100 0.89207 0.9416 VP-55_5IP_HAC_10WT_3X144_VF100 10 1605 144 100 0.86394 0.9394 6.6.3.1 Variation of Fill Parameter Study - HAC Package Array For the variation of fill percentage parameter study of a package array under HAC, the limit-defining U-235 masses were held constant as the fill percentage of the 5-inch pipe container was varied. This resulted in a variation of the amount of high-density polyethylene (HDPE) moderator, thus a variation of the H/U-235 ratio, to determine which fill percentage would produce the maximum value of keff + 2.

Case VP-55_5IP_HAC_100WT_3X105_VF080 is a case that models the Versa-Pac 55-gallon version (VP-55) with the 5-inch pipe container (5IP) under Hypothetical Accident Conditions (HAC), with 100-wt.% U-235 enriched uranium (100WT) in an array that is 3 packages tall with 105 total packages (3X105), in the Variation of Fill parameter study (VF) and with a 5-inch pipe fill percentage of 80% (080).

Table 6.6.3-2 shows the values of keff and for the different fill percentages examined. Note the limit-defining cases are highlighted. Figure 6.6.3-1 plots the results. The following list summarizes the results presented in Table 6.6.3-1:

• For 100-wt.% U-235 enriched uranium, a fill of 95% with 695 g of U-235 results in the maximum value of keff + 2 of 0.89434 with a value of H/U-235 of 311.02.

• For 20-wt.% U-235 enriched uranium, a fill of 100% with 1215 g of U-235 results in the maximum value of keff + 2 of 0.89207 with a value of H/U-235 of 179.69.

• For 10-wt.% U-235 enriched uranium, a fill of 100% with 1605 g of U-235 results in the maximum value of keff + 2 of 0.86394 with a value of H/U-235 of 125.31.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.3-2. Fill Percentage Sensitivity of the Five-Inch Pipe Container - HAC Package Array Fill H/U-Case keff keff + 2 Percentage 235 100-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_100WT_3X105_VF080 80 261.64 0.89227 0.00054 0.89335 VP-55_5IP_HAC_100WT_3X105_VF085 85 278.10 0.89247 0.00056 0.89359 VP-55_5IP_HAC_100WT_3X105_VF090 90 294.56 0.8921 0.00056 0.89322 VP-55_5IP_HAC_100WT_3X105_VF095 95 311.02 0.89316 0.00059 0.89434 VP-55_5IP_HAC_100WT_3X105_VF100 100 327.48 0.89162 0.00057 0.89276 20-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_20WT_3X105_VF080 80 142.03 0.86593 0.00058 0.86709 VP-55_5IP_HAC_20WT_3X105_VF085 85 151.44 0.8737 0.00058 0.87486 VP-55_5IP_HAC_20WT_3X105_VF090 90 160.86 0.87884 0.00056 0.87996 VP-55_5IP_HAC_20WT_3X105_VF095 95 170.27 0.88577 0.00056 0.88689 VP-55_5IP_HAC_20WT_3X105_VF100 100 179.69 0.89097 0.00055 0.89207 10-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_10WT_3X144_VF080 80 96.80 0.81999 0.00053 0.82105 VP-55_5IP_HAC_10WT_3X144_VF085 85 103.93 0.83262 0.00055 0.83372 VP-55_5IP_HAC_10WT_3X144_VF090 90 111.05 0.84331 0.00052 0.84435 VP-55_5IP_HAC_10WT_3X144_VF095 95 118.18 0.85372 0.00052 0.85476 VP-55_5IP_HAC_10WT_3X144_VF100 100 125.31 0.86286 0.00054 0.86394 0.9 0.89 0.88 0.87 keff + 2 0.86 100-wt.%

0.85 20-wt.%

0.84 10-wt.%

0.83 0.82 0.81 80 85 90 95 100 Fill Percentage Figure 6.6.3-1. Variation of Fill Sensitivity - HAC Package Array 6-220

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.3.2 Variation of Fissile Mass Parameter Study - HAC Package Array In the variation of fissile mass parameter study of a package array under NCT, the most reactive fill percentages, as determined in the variation of fill percentage parameter study, were held constant as the H/U-235 ratio was varied, therefore varying the mass of U-235 in the 5-inch pipe container. This parameter study shows that the fissile mass selected, and its corresponding ratio of H/U-235, is the most limiting under the USL.

Case VP-55_5IP_NCT_100WT_4X252_VM655 models the Variation of Fissile Mass (VM) parameter study with 655 g of U-235 (655).

Table 6.6.3-3 shows the values of keff and for the different fissile mass amounts examined. Note that the mass limit-defining cases are highlighted. Figure 6.6.3-2 through Figure 6.6.3-4 plot the results. The results are summarized as follows:

• For 100-wt.% U-235 enriched uranium, a U-235 mass limit of 695 g with the 5-inch pipe container 95% full results in the most limiting configuration under the USL with a keff + 2 of 0.89434 and a value of H/U-235 of 311.02.

• For 20-wt.% U-235 enriched uranium, a U-235 mass limit of 1215 g with the 5-inch pipe container 100% full results in the most limiting configuration under the USL with a keff + 2 of 0.89207 and a value of H/U-235 of 179.69.

• For 10-wt.% U-235 enriched uranium, a U-235 mass limit of 1605 g with the 5-inch pipe container 100% full results in the peak value of keff for any U-235 mass analyzed. The peak case has keff + 2 of 0.86394 with the 5-inch pipe container 100% full and with a value of H/U-235 of 125.31. Therefore, it is concluded that 10-wt.% U-235 is volume limited by the 5-inch pipe.

Table 6.6.3-3. U-235 Mass Sensitivity of the Five-Inch Pipe Container - HAC Package Array Case Mass U-235 (g) H/U-235 keff keff + 2 100-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_100WT_3X105_VM655 655 330.11 0.88063 0.00064 0.88191 VP-55_5IP_HAC_100WT_3X105_VM675 675 320.28 0.88699 0.00058 0.88815 VP-55_5IP_HAC_100WT_3X105_VM695 695 311.02 0.89316 0.00059 0.89434 VP-55_5IP_HAC_100WT_3X105_VM715 715 302.27 0.89727 0.00053 0.89833 VP-55_5IP_HAC_100WT_3X105_VM735 735 294.00 0.90231 0.00068 0.90367 20-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_20WT_3X105_VM1115 1115 196.58 0.88445 0.00055 0.88555 VP-55_5IP_HAC_20WT_3X105_VM1165 1165 187.77 0.88764 0.00054 0.88872 VP-55_5IP_HAC_20WT_3X105_VM1215 1215 179.69 0.89097 0.00055 0.89207 VP-55_5IP_HAC_20WT_3X105_VM1265 1265 172.24 0.89416 0.00052 0.89520 VP-55_5IP_HAC_20WT_3X105_VM1315 1315 165.37 0.89562 0.00057 0.89676 10-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_10WT_3X144_VM1505 1505 134.78 0.86162 0.00052 0.86266 VP-55_5IP_HAC_10WT_3X144_VM1555 1555 129.89 0.86254 0.00055 0.86364 VP-55_5IP_HAC_10WT_3X144_VM1605 1605 125.31 0.86286 0.00054 0.86394 VP-55_5IP_HAC_10WT_3X144_VM1655 1655 121.00 0.86293 0.00051 0.86395 VP-55_5IP_HAC_10WT_3X144_VM1705 1705 116.95 0.86248 0.00054 0.86356 6-221

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.905 0.9 0.895 keff + 2 0.89 0.885 0.88 650 660 670 680 690 700 710 720 730 740 U-235 Mass (g)

Figure 6.6.3-2. Variation of U-235 Mass Sensitivity - U(100) HAC Package Array 0.901 0.897 0.893 keff + 2 0.889 0.885 0.881 1100 1150 1200 1250 1300 1350 U-235 Mass (g)

Figure 6.6.3-3. Variation of U-235 Mass Sensitivity - U(20) HAC Package Array 6-222

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.873 0.868 keff + 2 0.863 0.858 0.853 1450 1500 1550 1600 1650 1700 1750 U-235 Mass (g)

Figure 6.6.3-4. Variation of U-235 Mass Sensitivity - U(10) HAC Package Array 6.6.3.3 Array Configuration Parameter Study - HAC Package Array In the array configuration sensitivity parameter study of a package array under HAC, several different array configurations were examined to verify the CSI-limiting configuration was properly modeled. The two variables modified were the height of the array, in number of packages, and the overall size of the array; that is, the number of packages in the array. Three different package heights2, 3, and 4 packages tallwere modeled with several different array sizes each, maintaining 2N number of packages around 105 for a CSI = 1.0 for U(100) and U(20) and 2N number of packages around 144 for a CSI = 0.7 for U(10).

Table 6.6.3-4 through Table 6.6.3-6 show the values of keff and for the different array configurations examined. Figure 6.6.3-5 through Figure 6.6.3-7 plot the results for visual inspection. Note the limiting cases are highlighted. As shown, an array configuration with a height of three packages bounding for all enrichment levels. The limiting keff + 2 values are further below the USL since the NCT package array analysis defines the subcritical mass limits.

For U(100) and U(20), the 3x105 array size resulted in the limiting value of keff + 2 under the USL while maintaining a CSI = 1.0. For U(10), the 3x144 array size is chosen as the HAC limit-defining case. Limiting cases are selected for the smallest array size that results in the desired CSI. Package stacking height is selected based on the limiting case for the array size.

The fissile mass configuration modeled for the array configuration study is as follows:

• For 100-wt.% U-235 enriched uranium, all cases were modeled with a fill of 95 percent and with 695 g of U-235. The H/U-235 for all cases modeled was 311.02.

• For 20-wt.% U-235 enriched uranium, all cases were modeled with a fill of 100 percent and with 1215 g of U-235. The H/U-235 for all cases modeled was 179.69.

• For 10-wt.% U-235 enriched uranium, all cases were modeled with a fill of 100 percent and with 1605 g of U-235. The H/U-235 for all cases modeled was 125.31.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.3-4. Array Configuration Sensitivity of the 5-Inch Pipe - U(100) HAC Package Array Case Array Height Array Size keff keff + 2 VP-55_5IP_HAC_100WT_2X096_AS 2 96 0.8873 0.00051 0.88832 VP-55_5IP_HAC_100WT_2X104_AS 2 104 0.89102 0.00054 0.8921 VP-55_5IP_HAC_100WT_2X112_AS 2 112 0.89602 0.00053 0.89708 VP-55_5IP_HAC_100WT_3X099_AS 3 99 0.88933 0.00052 0.89037 VP-55_5IP_HAC_100WT_3X105_AS 3 105 0.89316 0.00059 0.89434 VP-55_5IP_HAC_100WT_3X108_AS 3 108 0.89691 0.00056 0.89803 VP-55_5IP_HAC_100WT_3X112_AS 3 112 0.90096 0.00056 0.90208 VP-55_5IP_HAC_100WT_4X092_AS 4 92 0.87609 0.00054 0.87717 VP-55_5IP_HAC_100WT_4X100_AS 4 100 0.88208 0.00056 0.8832 VP-55_5IP_HAC_100WT_4X108_AS 4 108 0.89126 0.00052 0.8923 Table 6.6.3-5. Array Configuration Sensitivity of the 5-Inch Pipe Container - U(20) HAC Package Array Case Array Height Array Size keff keff + 2 VP-55_5IP_HAC_20WT_2X096_AS 2 96 0.88555 0.00056 0.88667 VP-55_5IP_HAC_20WT_2X104_AS 2 104 0.88815 0.00056 0.88927 VP-55_5IP_HAC_20WT_2X112_AS 2 112 0.89232 0.00055 0.89342 VP-55_5IP_HAC_20WT_3X099_AS 3 99 0.88785 0.00059 0.88903 VP-55_5IP_HAC_20WT_3X105_AS 3 105 0.89097 0.00055 0.89207 VP-55_5IP_HAC_20WT_3X108_AS 3 108 0.89554 0.00058 0.8967 VP-55_5IP_HAC_20WT_3X112_AS 3 112 0.90007 0.00057 0.90121 VP-55_5IP_HAC_20WT_4X092_AS 4 92 0.8749 0.0006 0.8761 VP-55_5IP_HAC_20WT_4X100_AS 4 100 0.88175 0.00054 0.88283 VP-55_5IP_HAC_20WT _4X108_AS 4 108 0.89014 0.0006 0.89134 Table 6.6.3-6. Array Configuration Sensitivity of the 5-Inch Pipe Container - U(10) HAC Package Array Case Array Height Array Size keff keff + 2 VP-55_5IP_HAC_10WT_2X136_AS 2 136 0.8498 0.00054 0.85088 VP-55_5IP_HAC_10WT_2X144_AS 2 144 0.85309 0.00054 0.85417 VP-55_5IP_HAC_10WT_2X154_AS 2 154 0.85379 0.00054 0.85487 VP-55_5IP_HAC_10WT_3X132_AS 3 132 0.85432 0.00054 0.8554 VP-55_5IP_HAC_10WT_3X138_AS 3 138 0.85759 0.00056 0.85871 VP-55_5IP_HAC_10WT_3X144_AS 3 144 0.86286 0.00054 0.86394 VP-55_5IP_HAC_10WT_3X156_AS 3 156 0.86711 0.00057 0.86825 VP-55_5IP_HAC_10WT_4X132_AS 4 132 0.8518 0.0006 0.853 VP-55_5IP_HAC_10WT_4X144_AS 4 144 0.86027 0.00051 0.86129 VP-55_5IP_HAC_10WT _4X156_AS 4 156 0.8639 0.00053 0.86496 6-224

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.904 0.9 0.896 0.892 keff + 2 0.888 2X 0.884 3X 4X 0.88 0.876 0.872 90 95 100 105 110 115 120 Array SIze Figure 6.6.3-5. Array Configuration Sensitivity - U(100) HAC Package Array 0.904 0.9 0.896 0.892 keff + 2 0.888 2X 0.884 3X 4X 0.88 0.876 0.872 90 95 100 105 110 115 120 Array SIze Figure 6.6.3-6. Array Configuration Sensitivity - U(20) HAC Package Array 6-225

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.872 0.868 0.864 keff + 2 0.86 2X 3X 0.856 4X 0.852 0.848 130 135 140 145 150 155 160 Array SIze Figure 6.6.3-7. Array Configuration Sensitivity - U(10) HAC Package Array 6.6.3.4 Partial Moderation Density Parameter Study - HAC Package Array In the partial moderation density parameter study of the HAC package array, the effective density of the HDPE moderator was reduced to examine its effect on keff. The limiting fill percentage and the U-235 mass limit were held constant as the density of the HDPE was reduced. This reduction in HDPE density resulted in a decrease of the H/U-235 ratio. Case VP-55_5IP_HAC_100WT_

3X105_PM060 models the Partial Moderation (PM) parameter study with 60% (060) density of HDPE modeled. Table 6.6.3-7 shows the values of keff and for the different partial moderation levels examined. Note the limit-defining cases are highlighted. Figure 6.6.3-8 plots the results.

As shown, as the moderator density and the H/U-235 ratio are decreased, the value of keff + 2 also decreases. The following list summarizes the partial moderation density sensitivity results:

• For 100-wt.% U-235 enriched uranium, full-density HDPE results in the maximum value of keff + 2 of 0.89434 with a value of H/U-235 of 311.02.

• For 20-wt.% U-235 enriched uranium, full-density HDPE results in the maximum value of keff + 2 of 0.89207 with a value of H/U-235 of 179.69.

• For 10-wt.% U-235 enriched uranium, full-density HDPE results in the maximum value of keff + 2 of 0.86394 with a value of H/U-235 of 125.31.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.3-7. Partial Moderation Density Sensitivity of the 5-Inch Pipe Container - HAC Package Array Percentage of Full Case H/U-235 keff keff + 2 Density HDPE 100-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_100WT_3X105_PM060 60 186.61 0.61042 0.00056 0.61154 VP-55_5IP_HAC_100WT_3X105_PM070 70 217.71 0.69505 0.00054 0.69613 VP-55_5IP_HAC_100WT_3X105_PM080 80 248.81 0.77082 0.00071 0.77224 VP-55_5IP_HAC_100WT_3X105_PM090 90 279.91 0.83482 0.00057 0.83596 VP-55_5IP_HAC_100WT_3X105_PM100 100 311.02 0.89316 0.00059 0.89434 20-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_20WT_3X105_PM060 60 107.81 0.61197 0.0005 0.61297 VP-55_5IP_HAC_20WT_3X105_PM070 70 125.78 0.69477 0.00053 0.69583 VP-55_5IP_HAC_20WT_3X105_PM080 80 143.75 0.76653 0.00052 0.76757 VP-55_5IP_HAC_20WT_3X105_PM090 90 161.72 0.83166 0.0006 0.83286 VP-55_5IP_HAC_20WT_3X105_PM100 100 179.69 0.89097 0.00055 0.89207 10-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_10WT_3X144_PM060 60 75.19 0.60709 0.0005 0.60809 VP-55_5IP_HAC_10WT_3X144_PM070 70 87.72 0.68197 0.00056 0.68309 VP-55_5IP_HAC_10WT_3X144_PM080 80 100.25 0.7477 0.00052 0.74874 VP-55_5IP_HAC_10WT_3X144_PM090 90 112.78 0.80823 0.00052 0.80927 VP-55_5IP_HAC_10WT_3X144_PM100 100 125.31 0.86286 0.00054 0.86394 0.9 0.85 0.8 keff + 2 0.75 100-wt.%

20-wt.%

0.7 10-wt.

0.65 0.6 60 70 80 90 100 Moderator Density (%)

Figure 6.6.3-8. Partial Moderation Density Sensitivity - HAC Package Array 6-227

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.3.5 Partial Fill Parameter Study - HAC Package Array For the partial fill parameter study of a package array under HAC, the limit-defining H/U-235 ratio for each enrichment level was held constant as several partial fill percentages of the 5-inch pipe container were examined to determine their effect on keff. Varying the fill percentage in this fashionholding the H/U-235 ratio constant resulted in varying amounts of fissile material. This study shows that a reduction in fissile mass will not result in a configuration that is more reactive than the evaluated mass limit. A decrease in keff + 2 for all partial fills that are less than the limit-defining fill of 100% is the expected behavior if the limiting fill percentage has been properly identified.

Case VP-55_5IP_HAC_100WT_3X105_PF010 models the Partial Fill (PF) parameter study with the five-inch pipe container 10% full (010).

Table 6.6.3-8 shows the values of keff and for the different partial moderation levels examined.

Note the most limiting case is highlighted. Figure 6.6.3-9 plots the results. As the fill percentages are reduced while the limit-defining H/U-235 ratio is held constant, the value of keff + 2 also reduces, as shown in Table 6.6.3-8. This shows that the lower fill percentages (i.e., reduced fissile mass) are not more reactive. At a reduced fill percentage (i.e., lower fissile mass), there is available volume to optimize H/U-235. While the increase in H/U-235 may increase keff of the system, it will not increase beyond the limiting case defined (this effect is evaluated in Section 6.4.3.2 for a single package).

The results are summarized as follows:

• For 100-wt.% U-235 enriched uranium, the limit-defining fill percentage of 95% results in the maximum value of keff + 2 of 0.89434 with a value of H/U-235 of 311.02.

• For 20-wt.% U-235 enriched uranium, the limit-defining fill percentage of 100% results in the maximum value of keff + 2 of 0.89207 with a value of H/U-235 of 179.69.

• For 10-wt.% U-235 enriched uranium, the limit-defining fill percentage of 100% results in the maximum value of keff + 2 of 0.86394 with a value of H/U-235 of 125.31.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.3-8. Partial Fill Sensitivity of the 5-Inch Pipe Container - HAC Package Array Fill U-235 Case keff keff + 2 Percentage Mass (g) 100-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_100WT_3X105_PF010 10 73.2 0.29451 0.0004 0.29531 VP-55_5IP_HAC_100WT_3X105_PF030 30 219.5 0.65954 0.00055 0.66064 VP-55_5IP_HAC_100WT_3X105_PF050 50 365.8 0.77699 0.00056 0.77811 VP-55_5IP_HAC_100WT_3X105_PF070 70 512.1 0.83872 0.00052 0.83976 VP-55_5IP_HAC_100WT_3X105_PF090 90 658.4 0.88319 0.00057 0.88433 VP-55_5IP_HAC_100WT_3X105_PF095 95 695.0 0.89316 0.00059 0.89434 20-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_20WT_3X105_PF010 10 121.5 0.30331 0.0004 0.30411 VP-55_5IP_HAC_20WT_3X105_PF030 30 364.5 0.65331 0.00053 0.65437 VP-55_5IP_HAC_20WT_3X105_PF050 50 607.5 0.76638 0.00057 0.76752 VP-55_5IP_HAC_20WT_3X105_PF070 70 850.5 0.82855 0.00056 0.82967 VP-55_5IP_HAC_20WT_3X105_PF090 90 1093.5 0.8729 0.00056 0.87402 VP-55_5IP_HAC_20WT_3X105_PF095 95 1154.3 0.88255 0.00057 0.88369 VP-55_5IP_HAC_20WT_3X105_PF100 100 1215.0 0.89097 0.00055 0.89207 10-wt.% U-235 Enriched Uranium VP-55_5IP_HAC_10WT_3X105_PF010 10 160.5 0.2932 0.00038 0.29396 VP-55_5IP_HAC_10WT_3X105_PF030 30 481.5 0.62292 0.00051 0.62394 VP-55_5IP_HAC_10WT_3X105_PF050 50 802.5 0.73634 0.00052 0.73738 VP-55_5IP_HAC_10WT_3X105_PF070 70 1123.5 0.79841 0.00059 0.79959 VP-55_5IP_HAC_10WT_3X105_PF090 90 1444.5 0.84279 0.00054 0.84387 VP-55_5IP_HAC_10WT_3X105_PF095 95 1524.8 0.85416 0.00052 0.8552 VP-55_5IP_HAC_10WT_3X105_PF100 100 1605.0 0.86286 0.00054 0.86394 6-229

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.85 0.75 0.65 keff + 2 100-wt.%

0.55 20-wt.%

0.45 10-wt.%

0.35 0.25 0 20 40 60 80 100 Partial Fill (%)

Figure 6.6.3-9. Partial Fill Sensitivity - HAC Package Array 6.6.3.6 Flooding Study - HAC Package Array For the flooding study, various configurations of flooding were examined. The water is modeled as light water with a nominal density of 0.9982 g/cm3. A flooding configuration consisted of the volume fraction of flooding modeled and the location of the flooding. Volume fractions of 0.00001 through 1.0 were examined and the following regions of the package array model were separately flooded:

• Configuration 1: Inside the package

• Configuration 2: Between packages

• Configuration 3: Inside the containment only

• Configuration 4: All of the above (everywhere)

VP-55_5IP_HAC_100WT_3X105_IM1_1 models Configuration 1 of the flooding parameter study (IM1) at a volume fraction of 0.00001 (1).

Table 6.6.3-9 through Table 6.6.3-11 show the values of keff and for the different configurations of flooding modeled for each enrichment level, respectively. Figure 6.6.3-10 through Figure 6.6.3-12 plot the information for visual inspection of the trends presented in the tables. For all configurations, the first three volume fractions of flooding modeled result in no significant difference in values of keff + 2. This is due to the fact that the fissile material is already optimally moderated. As the volume fraction of the flooding increases, the value of keff + 2 will generally decrease as the value of keff + 2 approaches a fully flooded, single package with full water reflection. No particular flooding fraction results in any significant increase in keff + 2. Therefore, the baseline flooding with a volume fraction of 0.0001 modeled everywhere (i.e., configuration 4) is bounding. Note the cases with the highest values of keff + 2 of each configuration are highlighted.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.3-9. Flooding Study inch Pipe U(100) HAC Package Array Case Volume Fraction keff keff + 2 Configuration 0: No Flooding VP-55_5IP_HAC_100WT_3X105_IM0_0 0.0 0.89197 0.00058 0.89313 Configuration 1: Inside Packages VP-55_5IP_HAC_100WT_3X105_IM1_1 0.00001 0.89207 0.00053 0.89313 VP-55_5IP_HAC_100WT_3X105_IM1_2 0.0001 0.89276 0.00053 0.89382 VP-55_5IP_HAC_100WT_3X105_IM1_3 0.001 0.89088 0.00051 0.8919 VP-55_5IP_HAC_100WT_3X105_IM1_4 0.01 0.88615 0.00056 0.88727 VP-55_5IP_HAC_100WT_3X105_IM1_5 0.1 0.83139 0.00053 0.83245 VP-55_5IP_HAC_100WT_3X105_IM1_6 0.5 0.81634 0.00052 0.81738 VP-55_5IP_HAC_100WT_3X105_IM1_7 1 0.83289 0.00052 0.83393 Configuration 2: Between Packages VP-55_5IP_HAC_100WT_3X105_IM2_1 0.00001 0.89134 0.00054 0.89242 VP-55_5IP_HAC_100WT_3X105_IM2_2 0.0001 0.89186 0.00058 0.89302 VP-55_5IP_HAC_100WT_3X105_IM2_3 0.001 0.89222 0.00062 0.89346 VP-55_5IP_HAC_100WT_3X105_IM2_4 0.01 0.89224 0.00055 0.89334 VP-55_5IP_HAC_100WT_3X105_IM2_5 0.1 0.88549 0.00054 0.88657 VP-55_5IP_HAC_100WT_3X105_IM2_6 0.5 0.84282 0.00053 0.84388 VP-55_5IP_HAC_100WT_3X105_IM2_7 1 0.80929 0.00057 0.81043 Configuration 3: Inner Container Only VP-55_5IP_HAC_100WT_3X105_IM3_1 0.00001 0.89097 0.00055 0.89207 VP-55_5IP_HAC_100WT_3X105_IM3_2 0.0001 0.89136 0.00053 0.89242 VP-55_5IP_HAC_100WT_3X105_IM3_3 0.001 0.89313 0.00062 0.89437 VP-55_5IP_HAC_100WT_3X105_IM3_4 0.01 0.89067 0.00055 0.89177 VP-55_5IP_HAC_100WT_3X105_IM3_5 0.1 0.86993 0.00054 0.87101 VP-55_5IP_HAC_100WT_3X105_IM3_6 0.5 0.84526 0.00051 0.84628 VP-55_5IP_HAC_100WT_3X105_IM3_7 1 0.8546 0.00053 0.85566 Configuration 4: All Regions VP-55_5IP_HAC_100WT_3X105_IM4_1 0.00001 0.89246 0.00056 0.89358 VP-55_5IP_HAC_100WT_3X105_IM4_2 0.0001 0.89316 0.00059 0.89434 VP-55_5IP_HAC_100WT_3X105_IM4_3 0.001 0.89206 0.00055 0.89316 VP-55_5IP_HAC_100WT_3X105_IM4_4 0.01 0.88726 0.00056 0.88838 VP-55_5IP_HAC_100WT_3X105_IM4_5 0.1 0.82513 0.00061 0.82635 VP-55_5IP_HAC_100WT_3X105_IM4_6 0.5 0.8139 0.00054 0.81498 VP-55_5IP_HAC_100WT_3X105_IM4_7 1 0.83088 0.00055 0.83198 6-231

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.3-10. Flooding Study inch Pipe U(20) HAC Package Array Volume Case keff keff + 2 Fraction Configuration 0: No Interspersed Moderation VP-55_5IP_HAC_20WT_3X105_IM0 0.0 0.89089 0.00062 0.89213 Configuration 1: Inside Packages VP-55_5IP_HAC_20WT_3X105_IM1_1 0.00001 0.89009 0.00052 0.89113 VP-55_5IP_HAC_20WT_3X105_IM1_2 0.0001 0.89109 0.00056 0.89221 VP-55_5IP_HAC_20WT_3X105_IM1_3 0.001 0.8908 0.00052 0.89184 VP-55_5IP_HAC_20WT_3X105_IM1_4 0.01 0.8877 0.00053 0.88876 VP-55_5IP_HAC_20WT_3X105_IM1_5 0.1 0.83146 0.00051 0.83248 VP-55_5IP_HAC_20WT_3X105_IM1_6 0.5 0.81519 0.00054 0.81627 VP-55_5IP_HAC_20WT_3X105_IM1_7 1 0.83092 0.00053 0.83198 Configuration 2: Between Packages VP-55_5IP_HAC_20WT_3X105_IM2_1 0.00001 0.89129 0.00059 0.89247 VP-55_5IP_HAC_20WT_3X105_IM2_2 0.0001 0.89025 0.00053 0.89131 VP-55_5IP_HAC_20WT_3X105_IM2_3 0.001 0.89119 0.0006 0.89239 VP-55_5IP_HAC_20WT_3X105_IM2_4 0.01 0.89071 0.00054 0.89179 VP-55_5IP_HAC_20WT_3X105_IM2_5 0.1 0.88658 0.00056 0.8877 VP-55_5IP_HAC_20WT_3X105_IM2_6 0.5 0.84376 0.00054 0.84484 VP-55_5IP_HAC_20WT_3X105_IM2_7 1 0.80784 0.00051 0.80886 Configuration 3: Inner Container Only VP-55_5IP_HAC_20WT_3X105_IM3_1 0.00001 0.89105 0.00056 0.89217 VP-55_5IP_HAC_20WT_3X105_IM3_2 0.0001 0.89166 0.00059 0.89284 VP-55_5IP_HAC_20WT_3X105_IM3_3 0.001 0.89105 0.00054 0.89213 VP-55_5IP_HAC_20WT_3X105_IM3_4 0.01 0.89063 0.00055 0.89173 VP-55_5IP_HAC_20WT_3X105_IM3_5 0.1 0.86961 0.00061 0.87083 VP-55_5IP_HAC_20WT_3X105_IM3_6 0.5 0.84456 0.00058 0.84572 VP-55_5IP_HAC_20WT_3X105_IM3_7 1 0.85327 0.00053 0.85433 Configuration 4: All Regions VP-55_5IP_HAC_20WT_3X105_IM4_1 0.00001 0.88992 0.00058 0.89108 VP-55_5IP_HAC_20WT_3X105_IM4_2 0.0001 0.89097 0.00055 0.89207 VP-55_5IP_HAC_20WT_3X105_IM4_3 0.001 0.89015 0.00053 0.89121 VP-55_5IP_HAC_20WT_3X105_IM4_4 0.01 0.8868 0.00056 0.88792 VP-55_5IP_HAC_20WT_3X105_IM4_5 0.1 0.82558 0.00054 0.82666 VP-55_5IP_HAC_20WT_3X105_IM4_6 0.5 0.81111 0.00052 0.81215 VP-55_5IP_HAC_20WT_3X105_IM4_7 1 0.83112 0.00054 0.8322 6-232

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.3-11. Flooding Study inch Pipe U(10) HAC Package Array Volume Case keff keff + 2 Fraction Configuration 0: No Interspersed Moderation VP-55_5IP_HAC_10WT_3X144_IM0 0.0 0.86271 0.00054 0.86379 Configuration 1: Inside Packages VP-55_5IP_HAC_10WT_3X144_IM1_1 0.00001 0.86204 0.00055 0.86314 VP-55_5IP_HAC_10WT_3X144_IM1_2 0.0001 0.86228 0.00052 0.86332 VP-55_5IP_HAC_10WT_3X144_IM1_3 0.001 0.86163 0.00051 0.86265 VP-55_5IP_HAC_10WT_3X144_IM1_4 0.01 0.85948 0.00053 0.86054 VP-55_5IP_HAC_10WT_3X144_IM1_5 0.1 0.79243 0.00061 0.79365 VP-55_5IP_HAC_10WT_3X144_IM1_6 0.5 0.77182 0.00048 0.77278 VP-55_5IP_HAC_10WT_3X144_IM1_7 1 0.78866 0.00054 0.78974 Configuration 2: Between Packages VP-55_5IP_HAC_10WT_3X144_IM2_1 0.00001 0.86187 0.0005 0.86287 VP-55_5IP_HAC_10WT_3X144_IM2_2 0.0001 0.86226 0.00055 0.86336 VP-55_5IP_HAC_10WT_3X144_IM2_3 0.001 0.86263 0.00053 0.86369 VP-55_5IP_HAC_10WT_3X144_IM2_4 0.01 0.86314 0.00054 0.86422 VP-55_5IP_HAC_10WT_3X144_IM2_5 0.1 0.85707 0.00055 0.85817 VP-55_5IP_HAC_10WT_3X144_IM2_6 0.5 0.80715 0.00057 0.80829 VP-55_5IP_HAC_10WT_3X144_IM2_7 1 0.7678 0.00055 0.7689 Configuration 3: Inner Container Only VP-55_5IP_HAC_10WT_3X144_IM3_1 0.00001 0.86237 0.00052 0.86341 VP-55_5IP_HAC_10WT_3X144_IM3_2 0.0001 0.8629 0.00052 0.86394 VP-55_5IP_HAC_10WT_3X144_IM3_3 0.001 0.86245 0.0005 0.86345 VP-55_5IP_HAC_10WT_3X144_IM3_4 0.01 0.86212 0.00055 0.86322 VP-55_5IP_HAC_10WT_3X144_IM3_5 0.1 0.83764 0.00055 0.83874 VP-55_5IP_HAC_10WT_3X144_IM3_6 0.5 0.80201 0.00054 0.80309 VP-55_5IP_HAC_10WT_3X144_IM3_7 1 0.80877 0.0005 0.80977 Configuration 4: All Regions VP-55_5IP_HAC_10WT_3X144_IM4_1 0.00001 0.86216 0.00054 0.86324 VP-55_5IP_HAC_10WT_3X144_IM4_2 0.0001 0.86286 0.00054 0.86394 VP-55_5IP_HAC_10WT_3X144_IM4_3 0.001 0.86219 0.00055 0.86329 VP-55_5IP_HAC_10WT_3X144_IM4_4 0.01 0.85855 0.00055 0.85965 VP-55_5IP_HAC_10WT_3X144_IM4_5 0.1 0.78545 0.00051 0.78647 VP-55_5IP_HAC_10WT_3X144_IM4_6 0.5 0.76795 0.00056 0.76907 VP-55_5IP_HAC_10WT_3X144_IM4_7 1 0.78675 0.00054 0.78783 6-233

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.9 0.89 0.88 0.87 0.86 keff + 2 IM1 0.85 IM2 0.84 IM3 0.83 IM4 0.82 0.81 0.8 0.00001 0.0001 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.3-10. Flooding Study inch Pipe U(100) HAC Package Array 0.9 0.89 0.88 0.87 0.86 keff + 2 IM1 0.85 IM2 0.84 IM3 0.83 IM4 0.82 0.81 0.8 0.00001 0.0001 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.3-11. Flooding Study inch Pipe U(20) HAC Package Array 6-234

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.88 0.86 0.84 keff + 2 IM1 0.82 IM2 0.8 IM3 IM4 0.78 0.76 0.00001 0.0001 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.3-12. Flooding Study inch Pipe U(10) HAC Package Array 6-235

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.4 5-inch Pipe with Hydrogen-Limited Contents The HAC array evaluation is split into three parts: 10-wt% U-metal contents with CSI=1.4, 10-wt%

uranium oxide contents with CSI=1.0, and 20-wt% U-metal contents with CSI=1.0. The results of the HAC Array homogeneous content analysis for the 5-inch Pipe with Hydrogen-Limited contents are provided below in Table 6.6.4-1. The cases for the 10 wt% analysis model two pipes pushed to the cavity wall and the cases for the 20 wt% analysis models one pipe pushed to the cavity wall as close to the surrounding packages as possible. Each analysis starts with a pipe entirely filled with U-metal or UO2. The second case in each (VFU=0.916) corresponds to 1.25 lbs of HDPE and the remainder of the pipe filled with U-metal or UO2. Each of the following cases reduce the quantity of U-metal or UO2 in the pipes and replace it with water to analyze a full range of moderation ratios and determine the peak value of keff. The results of these cases are plotted for each enrichment in Figure 6.6.4-1 and Figure 6.6.4-2. The HAC Array homogeneous analysis for this content demonstrates that there is a large margin to the USL for all cases.

Table 6.6.4-1. Summary 5-inch Pipe Hydrogen Limited Content HAC Array Homogeneous Criticality Evaluation k+2s Case a VFU b 10 wt% 10 wt% 20 wt%

U-Metal (CSI=1.4) UO2 (CSI=1.0) U-Metal (CSI=1.0)

HAC_X_01 1.000 0.62448 0.47125 0.68249 HAC_X_02 0.916 0.66768 0.54887 0.70413 HAC_X_03 0.800 0.70947 0.61680 0.72360 HAC_X_04 0.600 0.76825 0.72222 0.74494 HAC_X_05 0.400 0.82782 0.81983 0.76207 HAC_X_06 0.200 0.88994 0.88399 0.78990 HAC_X_07 0.180 0.89387 0.88361 0.79343 HAC_X_08 0.160 0.89753 0.88164 0.79714 HAC_X_09 0.140 0.89915 0.87589 0.79914 HAC_X_10 0.120 0.89863 0.86507 0.80114 HAC_X_11 0.100 0.89334 0.84690 0.80149 HAC_X_12 0.080 0.88156 0.81753 0.79726 HAC_X_13 0.060 0.85555 0.76719 0.78803 HAC_X_14 0.040 0.79949 0.67946 0.76107 a

Note: Placeholder X replaced by 010 for 10 wt% U-metal, 010_UO2 for 10 wt% UO2 results, or 020 for 20 wt% U-metal results.

b VFU refers to the volume fraction of the uranium compound, so for UO2 cases this refers to the volume fraction of UO2.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.90 0.85 0.80 keff + 2s 0.75 0.70 U-Metal (CSI=1.4) 0.65 UO2 (CSI=1.0) 0.60 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Volume Fraction U Figure 6.6.4-1. 10 wt% 5-inch Pipe Hydrogen Limited Content HAC Array Homogeneous Results 0.85 0.80 0.75 keff + 2s 0.70 0.65 0.60 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Volume Fraction U Figure 6.6.4-2. 20 wt% 5-inch Pipe Hydrogen Limited Content HAC Array Homogeneous Results 6-237

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 The results of the HAC array 10-wt% heterogeneous case studies for the two contents analyzed (U-metal and UO2) are listed in Table 6.6.4-2 and Table 6.6.4-3 and plotted along with the homogeneous results in Figure 6.6.4-3 and Figure 6.6.4-4. The results from this study show that for both contents, the USL is not exceeded, but the heterogeneous configuration is bounding of the homogeneous configuration. More particle sizes are modeled for the U-metal content than the UO2 content cases because the peak values for keff are much closer to the USL.

Table 6.6.4-2. 5-inch Pipe Hydrogen Limited Content 10 wt% U-Metal HAC Array Heterogeneous Criticality Evaluation Pitch keff + 2 for Particle Size (cm)

Ratio 0.025 0.05 0.075 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.5 2 0.79208 0.79390 0.79626 0.79842 0.80295 0.80656 0.81093 0.81402 0.81727 0.82029 0.82544 2.25 0.84223 0.84622 0.85055 0.85414 0.86056 0.86712 0.87224 0.87691 0.88106 0.88416 0.88883 2.5 0.87637 0.88201 0.88737 0.89303 0.90066 0.90622 0.91220 0.91563 0.91949 0.92187 0.92395 2.75 0.89716 0.90500 0.91055 0.91594 0.92380 0.92823 0.93307 0.93063 0.93434 0.93189 0.92695 3 0.90870 0.91544 0.92240 0.92629 0.93287 0.93370 0.93535 0.93421 0.93021 0.93208 0.92375 3.25 0.91028 0.91828 0.92261 0.92513 0.92890 0.92514 0.92358 0.92101 0.91125 0.89972 0.88327 3.5 0.90478 0.91198 0.91499 0.91711 0.91682 0.91129 0.90793 0.89441 0.89202 0.88244 0.85442 3.75 0.89342 0.89868 0.89956 0.89998 0.89623 0.88808 0.87112 0.86276 0.84189 0.84305 0.81399 4 0.87643 0.88010 0.88110 0.87685 0.86811 0.85504 0.84627 0.83397 0.81878 0.78625 0.77153 Table 6.6.4-3. 5-inch Pipe Hydrogen Limited Content 10 wt% UO2 HAC Array Heterogeneous Criticality Evaluation Pitch keff + 2 for Particle Size (cm)

Ratio 0.025 0.05 0.075 0.1 0.15 0.2 0.35 0.5 2 0.76336 0.76590 0.76700 0.76959 0.77278 0.77704 0.78581 0.79171 2.25 0.83710 0.84090 0.84413 0.84676 0.85247 0.85681 0.86631 0.86989 2.5 0.87578 0.87970 0.88359 0.88674 0.89208 0.89534 0.90195 0.90141 2.75 0.88925 0.89473 0.89825 0.90117 0.90573 0.90782 0.90608 0.89450 3 0.88713 0.89150 0.89584 0.89799 0.89948 0.89851 0.88764 0.87797 3.25 0.87313 0.87758 0.87981 0.88089 0.88057 0.87520 0.85710 0.82594 3.5 0.85086 0.85471 0.85580 0.85601 0.85376 0.84608 0.82573 0.78905 3.75 0.82183 0.82402 0.82397 0.82237 0.81831 0.80885 0.76436 0.74121 4 0.78888 0.79001 0.78926 0.78522 0.77656 0.76366 0.73275 0.69141 6-238

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.96 0.94 0.92 0.90 0.88 0.025 0.05 0.86 0.075 Keff + 2s 0.1 0.84 0.15 0.82 0.2 0.25 0.80 0.3 0.78 0.35 0.4 0 0.1 0.2 0.3 0.4 0.5 0.6 0.5 Volume Fraction U Hom.

Figure 6.6.4-3. 10 wt% U-Metal 5-inch Pipe Hydrogen Limited Content HAC Array Heterogeneous Results 0.94 0.92 0.90 0.88 0.86 0.84 0.025 0.05 0.82 Keff +2s 0.075 0.80 0.1 0.78 0.15 0.76 0.2 0.74 0.35 0.72 0.5 0 0.1 0.2 0.3 0.4 0.5 0.6 Hom.

Volume Fraction UO2 Figure 6.6.4-4. 10 wt% UO2 5-inch Pipe Hydrogen Limited Content HAC Array Heterogeneous Results 6-239

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 The results of the HAC array 20-wt% heterogeneous case studies for the bounding U-metal contents are listed in Table 6.6.4-4 and plotted along with the homogeneous results in Figure 6.6.4-5. The results from this study show that the USL is not exceeded, but the heterogeneous configuration is bounding of the homogeneous configuration Table 6.6.4-4. 5-inch Pipe Hydrogen Limited Content 20 wt% U-Metal HAC Array Heterogeneous Criticality Evaluation keff + 2 for Particle Size (cm)

Pitch Ratio 0.025 0.05 0.075 0.1 0.15 0.2 0.35 0.5 2 0.75212 0.75404 0.75505 0.75627 0.75882 0.76082 0.76686 0.77270 2.25 0.76850 0.77163 0.77391 0.77677 0.78128 0.78613 0.79559 0.80049 2.5 0.78419 0.78837 0.79216 0.79551 0.80129 0.80599 0.81634 0.81994 2.75 0.79619 0.80236 0.80583 0.81020 0.81634 0.82016 0.82501 0.81948 3 0.80470 0.81175 0.81597 0.81964 0.82465 0.82559 0.82207 0.81786 3.25 0.80970 0.81544 0.82013 0.82155 0.82508 0.82222 0.80985 0.78649 3.5 0.81077 0.81563 0.81917 0.82013 0.82132 0.81555 0.79823 0.76464 3.75 0.80767 0.81169 0.81289 0.81226 0.80901 0.80171 0.76055 0.73225 4 0.80062 0.80345 0.80414 0.80061 0.79169 0.77955 0.74258 0.69759 0.83 0.83 0.82 0.82 0.81 0.81 0.025 Keff + 2s 0.80 0.05 0.075 0.80 0.1 0.79 0.15 0.2 0.79 0.35 0.78 0.5 0 0.1 0.2 0.3 0.4 0.5 0.6 Hom.

Volume Fraction U Figure 6.6.4-5. 20 wt% U-Metal 5-inch Pipe Hydrogen Limited Content HAC Array Heterogeneous Results 6-240

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 For this content, the flooding study is only conducted for the 10 wt% U-metal contents, as this is the only content with a maximum keff near the USL and it has been repeatedly demonstrated that the effect of package flooding is minimal. The results of this study are shown in Table 6.6.4-5 and Figure 6.6.4-6. All results are still below the USL, thus, the results of the HAC package array heterogeneous study indicate that the 5-inch pipe Hydrogen Limited Content configuration can be shipped with unlimited material enriched to 10 wt%235U with a CSI=1.0 for uranium oxide materials and with a CSI=1.4 for all other uranium contents permissible in the Versa-Pac bounded by U-metal and 20 wt%235U with a CSI=1.0.

Table 6.6.4-5. HAC Array 10-wt% U-Metal (CSI=1.4) Flooding Study Results keff + 2 for Flooding Configurations Case Index a Flooding VF Interspersed Inner Cavity Outer Cavity All Regions Moderation (FLD1) (FLD2) (FLD4)

(FLD3)

FLDx_1 0.0001 0.93591 0.93570 0.93586 0.93535 FLDx_2 0.001 0.93597 0.93589 0.93572 0.93558 FLDx_3 0.01 0.93710 0.93518 0.93608 0.93597 FLDx_4 0.1 0.92982 0.89629 0.93488 0.87423 FLDx_5 0.5 0.88115 0.78160 0.89269 0.82278 FLDx_6 1 0.87242 0.74593 0.84773 0.83181 a

Note: x corresponds to the number label for the respective flooding case (e.g. FLD1).

0.98 0.94 0.90 0.86 Inner Cavity keff +2s (FLD1) 0.82 Outer Cavity (FLD2) 0.78 Interspersed 0.74 Moderation (FLD3) 0.70 0.0001 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.4-6. 10 wt% 5-inch Pipe Hydrogen Limited Content HAC Array Flooding Study Results 6-241

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5 1S/2S Cylinder 6.6.5.1 1S Cylinder, 100-wt.% U-235, HAC Package Array For the 1S cylinder with 100-wt.% U-235, HAC package array analysis, three (3) 1S cylinders were modeled, each in a separate 5-inch pipe in one VP-55, with a maximum uranium mass of 918 g (306 gU/pipe). The following variables represent the most reactive 1S cylinder, 100-wt.%

U-235, HAC package array configuration: a maximum uranium mass of 306 gU/cylinder, a partial 5-inch pipe fill height of 31.75 cm, a reflector thickness of 0 cm and a pipe spacing of 0.01 cm, 0.0001 volume fraction flooding in the interspersed moderation region with all other regions dry, 5-inch pipes in the bottom corner of the Versa-Pac inner cavity, a 104-package array stacked 2 packages tall, and fissile material in the form of UO2F2.

6.6.5.1.1 Most Reactive Cylinder Configuration In this study, several values of pipe spacing, cylinder reflector thickness, uranium mass, and pipe fill height were evaluated to determine the most reactive configuration. Table 6.6.5-1 through Table 6.6.5-4 show for 100-wt.% U-235, 1S cylinder, HAC package array analysis that 918 gU (the maximum uranium mass of 306 gU/cylinder), a partial cylinder fill height of 31.75 cm, a reflector thickness of 0.0 cm, pipe spacing of 0.01 cm, and a flooding volume fraction of 0.0001 in all floodable regions (FLD4_0.0001) is the bounding cylinder configuration. However, upon examining the flooding configuration in Table 6.6.5-5, interspersed moderation with a volume fraction of 0.0001 (FLD3_0.0001) is the bounding flooding configuration, with keff + 2 of 0.89935.

This case, VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD3_0.0001_in, is highlighted in Table 6.6.5-5. Figure 6.6.5-1 through Figure 6.6.5-5 plot these trends for visual inspection.

Because the bounding flooding configuration in Table 6.6.5-5 differs significantly from the flooding configuration modeled in Table 6.6.5-1 through Table 6.6.5-4, a second iteration of the most reactive configuration is examined in Section 6.3.2.1.2 using the new flooding configuration (FLD3_0.0001).

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.5-1. Effect of Pipe Spacing on keff - 1S, 100-wt.% U-235, HAC Package Array Pipe Case Spacing keff keff + 2 (cm)

VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_in 0.01 0.89696 0.00056 0.89808 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.5_in 0.50 0.88567 0.00055 0.88677 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_1_in 1.00 0.87239 0.00072 0.87383 Table 6.6.5-2. Effect of Reflector Thickness on keff - 1S, 100-wt.% U-235, HAC Package Array Reflector Case Thickness keff keff + 2 (cm)

VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_in 0.0 0.89696 0.00056 0.89808 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0.5_0.01_in 0.5 0.88989 0.00050 0.89089 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_1_0.01_in 1.0 0.88287 0.00060 0.88407 Table 6.6.5-3. Effect of Uranium Mass on keff - 1S, 100-wt.% U-235, HAC Package Array Uranium Case keff keff + 2 Mass (g)

VP-55_5IP_1S_100_HAC_UO2F2_3x105_200_31.75_0_0.01_in 200 0.78687 0.00043 0.78773 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_in 306 0.89696 0.00056 0.89808 Table 6.6.5-4. Effect of Fill Height on keff - 1S, 100-wt.% U-235, HAC Package Array Fill Height Case keff keff + 2 (cm)

VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_25.4_0_0.01_in 25.4 0.89228 0.00055 0.89338 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_in 31.8 0.89696 0.00056 0.89808 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_38.1_0_0.01_in 38.100 0.89134 0.00058 0.89250 6-243

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.5-5. Effect of Flooding Configuration on keff - 1S, 100-wt.% U-235, HAC Package Array Volume keff +

Case keff Fraction 2 Inner Cavity Flooded Only VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD1_0.0001_in 0.0001 0.89699 0.00047 0.89793 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD1_0.001_in 0.001 0.89711 0.00053 0.89817 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD1_0.01_in 0.01 0.89561 0.00068 0.89697 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD1_0.1_in 0.1 0.88964 0.00061 0.89086 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD1_0.5_in 0.5 0.86021 0.00049 0.86119 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD1_1_in 1.0 0.84682 0.00049 0.8478 Outer Cavity Flooded Only VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD2_0.0001_in 0.0001 0.89714 0.00069 0.89852 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD2_0.001_in 0.001 0.8977 0.00052 0.89874 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD2_0.01_in 0.01 0.89448 0.00052 0.89552 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD2_0.1_in 0.1 0.86189 0.00053 0.86295 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD2_0.5_in 0.5 0.79596 0.0006 0.79716 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD2_1_in 1.0 0.77696 0.00063 0.77822 Interspersed Moderation Only VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD3_0.0001_in 0.0001 0.89813 0.00061 0.89935 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD3_0.001_in 0.001 0.89762 0.00065 0.89892 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD3_0.01_in 0.01 0.89748 0.00053 0.89854 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD3_0.1_in 0.1 0.89194 0.00058 0.8931 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD3_0.5_in 0.5 0.86341 0.00053 0.86447 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD3_1_in 1.0 0.84063 0.0005 0.84163 All Regions Flooded VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD4_0.0001_in 0.0001 0.89696 0.00056 0.89808 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD4_0.001_in 0.001 0.89631 0.00068 0.89767 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD4_0.01_in 0.01 0.89339 0.0005 0.89439 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD4_0.1_in 0.1 0.85187 0.00055 0.85297 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD4_0.5_in 0.5 0.80777 0.00066 0.80909 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD4_1_in 1.0 0.8115 0.00058 0.81266 6-244

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of H/U-235 on keff + 2 0.9 0.895 0.89 k-eff + 2 0.885 0.88 0.875 0.87 0 0.2 0.4 0.6 0.8 1 1.2 Cylinder Spacing (cm)

Figure 6.6.5-1. Effect of Pipe Spacing - 1S, 100-wt.% U-235, HAC Package Array Effect of Reflector Thickness on keff + 2 0.91 0.905 0.9 0.895 k-eff + 2 0.89 0.885 0.88 0.875 0.87 0 0.2 0.4 0.6 0.8 1 1.2 Fill Height (cm)

Figure 6.6.5-2. Effect of Reflector Thickness - 1S, 100-wt.% U-235, HAC Package Array 6-245

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Uranium Mass on keff + 2 0.91 0.89 0.87 k-eff + 2 0.85 0.83 0.81 0.79 0.77 150 200 250 300 350 H/U-235 Figure 6.6.5-3. Effect of Uranium Mass - 1S, 100-wt.% U-235, HAC Package Array Effect of Fill Height on keff + 2 0.915 0.91 0.905 0.9 k-eff + 2 0.895 0.89 0.885 0.88 0.875 24 26 28 30 32 34 36 38 40 Fill Height (cm)

Figure 6.6.5-4. Effect of Fill Height - 1S, 100-wt.% U-235, HAC Package Array 6-246

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Flooding Configurations on keff + 2 0.92 0.9 0.88 0.86 k-eff + 2 Inner Cavity 0.84 Outer Cavity 0.82 Interspersed 0.8 All Regions 0.78 0.76 0.0001 0.001 0.01 0.1 1 Water Volume Fraction Figure 6.6.5-5. Effect of Flooding Configuration - 1S, 100-wt.% U-235, HAC Package Array 6-247

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.1.2 Flooding-Adjusted Most Reactive Configuration As shown in Section 6.6.5.1.1, a flooding configuration of interspersed moderation with an H2O volume fraction of 0.0001, with all other flooding regions as void (FLD3_0.0001), a pipe spacing of 0.01 cm, a reflector thickness of 0 cm, a uranium mass of 306 gU/pipe, and a fill height of 25.4 cm was the most reactive configuration. This section reexamines the fill height vs keff + 2 for the 1S cylinder package array under HAC with 100-wt.% U-235 enrichment for the FLD3_0.0001 flooding configuration.

As shown in Table 6.6.5-6, a fill height of 31.75 cm is also the bounding fill height given interspersed moderation with an H2O volume fraction of 0.0001 with all other flooding regions void. The most reactive case for the 100-wt.% U-235 1S cylinder HAC package array evaluation, VP-55_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_31.75_in, with keff + 2 of 0.89935, is highlighted. Figure 6.6.5-6 plots this trend for visual inspection. The pipe spacing, reflector thickness, and uranium mass sensitivity studies were not reexamined, as there is a clear and marked effect in these variables reducing keff established in Section 6.3.2.1.1. Also, because the same fill height was the most reactive case with the new FLD3_0.0001 configuration, it was not necessary to reexamine the flooding configuration.

Table 6.6.5-6. Effect of Fill Height on keff for FLD3_0.0001 - 1S, 100-wt.% U-235, HAC Package Array Fill Height keff +

Case keff (cm) 2 VP-55_5IP_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_25.4_in 25.4 0.89386 0.00049 0.89484 VP-55_5IP_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_28.575_in 28.575 0.89696 0.00056 0.89808 VP-55_5IP_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_31.75_in 31.75 0.89813 0.00061 0.89935 VP-55_5IP_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_34.925_in 34.925 0.89519 0.00061 0.89641 VP-55_5IP_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_38.1_in 38.1 0.89083 0.00052 0.89187 Effect of Fill Height on keff + 2 0.915 0.91 0.905 0.9 k-eff + 2 0.895 0.89 0.885 0.88 0.875 22 24 26 28 30 32 34 36 38 40 Fill Height (cm)

Figure 6.6.5-6. Effect of Fill Height vs keff for FLD3_0.0001 - 1S, 100-wt.% U-235, HAC Package Array 6-248

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.1.3 5-inch Pipe Positioning Sensitivity Study As shown in Table 6.6.5-7, modeling the 1S cylinder with 100-wt.% U-235 in a 5-inch pipe in the center of the inner cavity produces the bounding 5-inch pipe position for the HAC package array, with keff + 2 equivalent to 0.89935.

Table 6.6.5-7. Effect of 5-inch Pipe Group Positioning on keff - 1S, 100-wt.% U-235, HAC Package Array keff +

Case Centering keff 2

VP-55_5IP_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_31.75_in None 0.89813 0.00061 0.89935 Radial +

VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD3_0.0001_POS_1_in 0.88236 0.00050 0.88336 Axial VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD3_0.0001_POS_2_in Axial 0.88728 0.00051 0.88830 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_FLD3_0.0001_POS_3_in Radial 0.89446 0.00069 0.89584 6.6.5.1.4 Array Configuration As shown in Table 6.6.5-8, reducing or increasing the height of packages in the HAC package array, while modeling at least 100 packages, results in a significant increased value of keff + 2 for a reduced height array. A 2x104 array has a keff + 2 of 0.90124, compared with a 3x105 array with a keff + 2 of 0.90124. Therefore, an array of 104 packages stacked two packages tall is the bounding array configuration for 1S cylinders with 100-wt.% U-235 in the HAC package array evaluation.

Table 6.6.5-8. Effect of Array Configuration on keff - 1S, 100-wt.% U-235, HAC Package Array Array Total Case keff keff + 2 Height Packages VP-55_5IP_1S_100_HAC_UO2F2_2x104_306_31.75_0_0.01 2 104 0.90002 0.00061 0.90124 VP-55_5IP_1S_100_HAC_UO2F2_3x105_306_31.75_0_0.01_in 3 105 0.89813 0.00061 0.89935 VP-55_5IP_1S_100_HAC_UO2F2_4x100_306_31.75_0_0.01 4 100 0.89140 0.00065 0.89270 6-249

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.1.5 UF6 Fissile Solution Sensitivity Study As shown in Table 6.6.5-9 and Figure 6.6.5-7, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly. Therefore, UO2F2 is the bounding fissile configuration for 1S cylinders with 100-wt.% U-235, HAC package array evaluation.

Table 6.6.5-9. Effect of UF6 on keff - 1S, 100-wt.% U-235, HAC Package Array Fill Case Height keff keff + 2 (cm)

Uranyl Fluoride (UO2F2)

VP-55_5IP_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_25.4_in 25.4 0.89386 0.00049 0.89484 VP-55_5IP_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_28.575_in 28.575 0.89696 0.00056 0.89808 VP-55_5IP_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_31.75_in 31.75 0.89813 0.00061 0.89935 VP-55_5IP_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_34.925_in 34.925 0.89519 0.00061 0.89641 VP-55_5IP_1S_100_HAC_UO2F2_3x105_FLD3_0.0001_38.1_in 38.1 0.89083 0.00052 0.89187 Uranium Hexafluoride (UF6)

VP-55_5IP_1S_100_HAC_UF6_3x105_306_0_0.01_FLD3_0.0001_25.4_in 25.40 0.89007 0.00053 0.89113 VP-55_5IP_1S_100_HAC_UF6_3x105_306_0_0.01_FLD3_0.0001_31.75_in 31.75 0.89440 0.00056 0.89552 VP-55_5IP_1S_100_HAC_UF6_3x105_306_0_0.01_FLD3_0.0001_38.1_in 38.10 0.88920 0.00051 0.89022 Effect of UF6 Fissile Solution on keff + 2 0.915 0.91 0.905 0.9 k-eff + 2 0.895 UO2F2 0.89 UF6 0.885 0.88 0.875 20 25 30 35 40 Fill Height (cm)

Figure 6.6.5-7. Effect of UF6 on keff - 1S, 100-wt.% U-235, HAC Package Array 6-250

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.2 2S Cylinder, 100-wt.% U-235, HAC Package Array For the 100-wt.% U-235 2S cylinder HAC package array analysis, one (1) 2S cylinder was modeled with a maximum uranium mass of 1497 g/cylinder. The following variables represent the most reactive 2S cylinder, 100-wt.% U-235, HAC package array configuration: a maximum uranium mass of 1497 gU/cylinder, a maximum 5-inch pipe fill height of 53.975 cm, 0.0001 volume fraction flooding in all regions, 5-inch pipe in the bottom corner of the Versa-Pac inner cavity, a 105-package array stacked 3 packages tall, and fissile material in the form of UO2F2.

6.6.5.2.1 Most Reactive Cylinder Configuration In this study, several values of uranium mass, cylinder fill height, and cylinder spacing were evaluated to determine the most reactive configuration. Table 6.6.5-10 through Table 6.6.5-13 show for 100-wt.% U-235 2S cylinder HAC package array analysis that a reflector thickness of 1.0 cm, a maximum uranium mass of 1497 gU/cylinder, and a full pipe (53.975 cm) is the most reactive configuration, with keff + 2 of 0.86421. The most reactive case, VP-55_2S_100_NCT_

UO2F2_4x252_1250_20.003_5.5_in, is highlighted in these tables. Figure 6.6.5-8 through Figure 6.6.5-11 plot these trends for visual inspection.

Table 6.6.5-10. Effect of Reflector Thickness on keff - 2S, 100-wt.% U-235, HAC Package Array Reflector Case Thickness keff keff + 2 (cm)

VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_0.5_in 0.50 0.85833 0.00056 0.85945 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_0.75_in 0.75 0.86174 0.00057 0.86288 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_in 1.00 0.86309 0.00056 0.86421 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1.25_in 1.25 0.86232 0.00056 0.86344 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1.5_in 1.50 0.86246 0.00053 0.86352 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1.75_in 1.75 0.85863 0.00053 0.85969 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_2_in 2.00 0.85741 0.00061 0.85863 Table 6.6.5-11. Effect of Uranium Mass on keff - 2S, 100-wt.% U-235, HAC Package Array Uranium Case keff keff + 2 Mass (g)

VP-55_5IP_2S_100_HAC_UO2F2_3x105_1000_53.975_1_in 1000 0.81863 0.00055 0.81973 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_in 1497 0.86309 0.00056 0.86421 Table 6.6.5-12. Effect of Fill Height on keff - 2S, 100-wt.% U-235, HAC Package Array Fill Height Case keff keff + 2 (cm)

VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_38.1_1_in 38.10 0.81763 0.00061 0.81885 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_43.18_1_in 43.18 0.83513 0.00065 0.83643 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_in 53.975 0.86309 0.00056 0.86421 6-251

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.5-13. Effect of Flooding Configuration on keff - 2S, 100-wt.% U-235, HAC Package Array Volume keff +

Case keff Fraction 2 Inner Cavity Flooded Only VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD1_0.0001_in 0.0001 0.86233 0.00058 0.86349 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD1_0.001_in 0.001 0.86232 0.00055 0.86342 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD1_0.01_in 0.01 0.86032 0.00051 0.86134 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD1_0.1_in 0.1 0.8368 0.00058 0.83796 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD1_0.5_in 0.5 0.80547 0.00054 0.80655 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD1_1_in 1.0 0.81053 0.00052 0.81157 Outer Cavity Flooded Only VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD2_0.0001_in 0.0001 0.86097 0.00063 0.86223 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD2_0.001_in 0.001 0.86262 0.00061 0.86384 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD2_0.01_in 0.01 0.85767 0.00056 0.85879 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD2_0.1_in 0.1 0.80355 0.00057 0.80469 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD2_0.5_in 0.5 0.71989 0.00054 0.72097 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD2_1_in 1.0 0.70172 0.0006 0.70292 Interspersed Moderation Only VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD3_0.0001_in 0.0001 0.86172 0.00052 0.86276 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD3_0.001_in 0.001 0.86218 0.00058 0.86334 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD3_0.01_in 0.01 0.8618 0.00055 0.8629 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD3_0.1_in 0.1 0.85328 0.0006 0.85448 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD3_0.5_in 0.5 0.80396 0.00056 0.80508 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD3_1_in 1.0 0.76855 0.0005 0.76955 All Regions Flooded VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD4_0.0001_in 0.0001 0.86309 0.00056 0.86421 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD4_0.001_in 0.001 0.86145 0.00063 0.86271 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD4_0.01_in 0.01 0.85364 0.00056 0.85476 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD4_0.1_in 0.1 0.78562 0.00057 0.78676 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD4_0.5_in 0.5 0.76823 0.00053 0.76929 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_FLD4_1_in 1.0 0.78509 0.00051 0.78611 6-252

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Reflector Thickness on keff + 2 0.882 0.877 0.872 0.867 k-eff + 2 0.862 0.857 0.852 0.847 0.842 0.25 0.45 0.65 0.85 1.05 1.25 1.45 1.65 1.85 H/U-235 Figure 6.6.5-8. Effect of Reflector Thickness - 2S, 100-wt.% U-235, HAC Package Array Effect of Uranium Mass on keff + 2 0.87 0.86 0.85 k-eff + 2 0.84 0.83 0.82 0.81 0.8 900 1000 1100 1200 1300 1400 1500 1600 Mass Uranium (g)

Figure 6.6.5-9. Effect of Uranium Mass - 2S, 100-wt.% U-235, HAC Package Array 6-253

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Fill Height on keff + 2 0.87 0.865 0.86 0.855 0.85 k-eff + 2 0.845 0.84 0.835 0.83 0.825 0.82 0.815 35 37.5 40 42.5 45 47.5 50 52.5 55 Fill Height (cm)

Figure 6.6.5-10. Effect of Fill Height - 2S, 100-wt.% U-235, HAC Package Array Effect of Flooding Configurations on keff + 2 0.87 0.85 0.83 0.81 k-eff + 2 0.79 Inner Cavity 0.77 Outer Cavity 0.75 Interspersed 0.73 All Regions 0.71 0.69 0.0001 0.001 0.01 0.1 1 Water Volume Fraction Figure 6.6.5-11. Effect of Flooding Configurations - 2S, 100-wt.% U-235, HAC Package Array 6-254

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.2.2 Cylinder Positioning Sensitivity Study As shown in Table 6.6.5-14 modeling the 100-wt.% U-235 2S cylinder in the 5-inch pipe in the center of the inner cavity produces the bounding cylinder position for the HAC package array, with keff + 2 equivalent to 0.86421.

Table 6.6.5-14. Effect of 5-inch Pipe Positioning on keff - 2S, 20-wt.% U-235, HAC Package Array Case Centering keff keff + 2 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_in None 0.86309 0.00056 0.86421 Radial +

VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_POS_1_in 0.84441 0.00053 0.84547 Axial VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_POS_2_in Axial 0.85666 0.00059 0.85784 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_POS_3_in Radial 0.85124 0.00057 0.85238 6.6.5.2.3 Array Configuration As shown in Table 6.6.5-15, reducing or increasing the height of packages in the HAC package array, while modeling at least 100 packages (maintaining a CSI of 1.0), results in significantly reduced values of keff + 2. Therefore, an array of 105 packages stacked three packages tall is the bounding array configuration for the 2S cylinder with 100-wt.% U-235 HAC package array evaluation.

Table 6.6.5-15. Effect of Array Configuration on keff - 2S, 100-wt.% U-235, HAC Package Array Array Total Case keff keff + 2 Height Packages VP-55_5IP_2S_100_HAC_UO2F2_2x104_1497_53.975_1 2 104 0.85826 0.00060 0.85946 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_in 3 105 0.86309 0.00056 0.86421 VP-55_5IP_2S_100_HAC_UO2F2_4x100_1497_53.975_1 4 100 0.85327 0.00054 0.85435 6-255

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.2.4 UF6 Fissile Solution Sensitivity Study As shown in Table 6.6.5-16 and Figure 6.6.5-12, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly. Therefore, UO2F2 is the bounding fissile configuration for 2S cylinders with 100-wt.% U-235 in the HAC package array evaluation.

Table 6.6.5-16. Effect of UF6 on keff - 2S, 100-wt.% U-235, HAC Package Array Cylinder Case Spacing keff keff + 2 (cm)

Uranyl Fluoride (UO2F2)

VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_0.5_in 0.50 0.85833 0.00056 0.85945 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_0.75_in 0.75 0.86174 0.00057 0.86288 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1_in 1.00 0.86309 0.00056 0.86421 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1.25_in 1.25 0.86232 0.00056 0.86344 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1.5_in 1.50 0.86246 0.00053 0.86352 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_1.75_in 1.75 0.85863 0.00053 0.85969 VP-55_5IP_2S_100_HAC_UO2F2_3x105_1497_53.975_2_in 2.00 0.85741 0.00061 0.85863 Uranium Hexafluoride (UF6)

VP-55_5IP_2S_100_HAC_UF6_3x105_1497_53.975_0.5_in 0.50 0.84672 0.00058 0.84788 VP-55_5IP_2S_100_HAC_UF6_3x105_1497_53.975_0.75_in 0.75 0.84891 0.00058 0.85007 VP-55_5IP_2S_100_HAC_UF6_3x105_1497_53.975_1_in 1.00 0.85127 0.00052 0.85231 VP-55_5IP_2S_100_HAC_UF6_3x105_1497_53.975_1.25_in 1.25 0.85186 0.00054 0.85294 VP-55_5IP_2S_100_HAC_UF6_3x105_1497_53.975_1.5_in 1.50 0.85140 0.00053 0.85246 VP-55_5IP_2S_100_HAC_UF6_3x105_1497_53.975_1.75_in 1.75 0.84942 0.00061 0.85064 VP-55_5IP_2S_100_HAC_UF6_3x105_1497_53.975_2_in 2.00 0.84717 0.00063 0.84843 Effect of UF6 Fissile Solution on keff + 2 0.875 0.87 0.865 0.86 k-eff + 2 0.855 UO2F2 0.85 UF6 0.845 0.84 0.835 0 0.5 1 1.5 2 2.5 Reflector Thickness (cm)

Figure 6.6.5-12. Effect of UF6 on keff - 2S, 100-wt.% U-235, HAC Package Array 6-256

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.3 1S Cylinder, 20-wt.% U-235, HAC Package Array For the 1S cylinders with 20-wt.% U-235 HAC package array analysis, the equivalent of seven (7) 1S cylinders, with a maximum uranium mass of 2149 g (307 gU/cylinder), were modeled as a fissile solution sphere. This assumes the cylinders do not survive HAC. The following variables represent the most reactive 1S cylinder, 20-wt.% U-235, HAC package array configuration: a maximum uranium mass of 307 gU/cylinder, H/U-235 of 650, a fully flooded Versa-Pac inner cavity with all other regions dry, fissile sphere in the bottom corner of the Versa-Pac inner cavity, a 105-package array stacked 3 packages tall, and fissile material in the form of UO2F2.

6.6.5.3.1 Most Reactive Cylinder Configuration In this study, several values of sphere size (H/U-235) and uranium mass were evaluated to determine the most reactive configuration. Table 6.6.5-17 and Table 6.6.5-18 show for 20-wt.%

U-235 1S cylinders, HAC package array analysis that a value of H/U-235 of 850 and 2149 gU (the maximum uranium mass of 307 gU/cylinder) is the most reactive of these two variables.

However, these cases modeled a flooding configuration of 0.0001 volume fraction H2O in all floodable regions (FLD4_0.0001). In Table 6.6.5-19, a fully flooded inner cavity with all other regions void (FLD1_1) produces the bounding cylinder configuration for H/U-235 of 850, with keff + 2 of 0.82499. This case, VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD1_1_in, is highlighted in Table 6.6.5-19. Figure 6.6.5-13 through Figure 6.6.5-15 plot these trends for visual inspection.

Because the bounding flooding configuration in Table 6.6.5-19 differs significantly from the flooding configuration modeled in Table 6.6.5-17 and Table 6.6.5-18, a second iteration of the most reactive configuration is examined in Section 6.6.5.3.2 using the new flooding configuration (FLD1_1).

Table 6.6.5-17. Effect of Sphere Size (H/U-235) on keff - 1S, 20-wt.% U-235, HAC Package Array Case H/U-235 keff keff + 2 VP-55_1S_020_HAC_UO2F2_3x105_2149_700_in 700 0.81582 0.00044 0.81670 VP-55_1S_020_HAC_UO2F2_3x105_2149_750_in 750 0.81897 0.00046 0.81989 VP-55_1S_020_HAC_UO2F2_3x105_2149_800_in 800 0.81912 0.00055 0.82022 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_in 850 0.82006 0.00047 0.82100 VP-55_1S_020_HAC_UO2F2_3x105_2149_900_in 900 0.81876 0.00044 0.81964 VP-55_1S_020_HAC_UO2F2_3x105_2149_950_in 950 0.81582 0.00048 0.81678 Table 6.6.5-18. Effect of Uranium Mass on keff - 1S, 20-wt.% U-235, HAC Package Array Uranium Mass Case keff keff + 2

[per cylinder] (g)

VP-55_1S_020_HAC_UO2F2_3x105_700_850_in 700 [100] 0.50499 0.00055 0.50609 VP-55_1S_020_HAC_UO2F2_3x105_1400_850_in 1400 [200] 0.70000 0.00056 0.70112 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_in 2149 [307] 0.82006 0.00047 0.82100 6-257

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.5-19. Effect of Flooding Configuration on keff - 1S, 20-wt.% U-235, HAC Package Array Volume Case keff keff + 2 Fraction Inner Cavity Flooded Only VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD1_0.0001_in 0.0001 0.81965 0.00061 0.82087 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD1_0.001_in 0.001 0.81961 0.00046 0.82053 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD1_0.01_in 0.01 0.82023 0.00056 0.82135 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD1_0.1_in 0.1 0.82376 0.00051 0.82478 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD1_0.5_in 0.5 0.82291 0.00050 0.82391 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD1_1_in 1.0 0.82385 0.00057 0.82499 Outer Cavity Flooded Only VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD2_0.0001_in 0.0001 0.81868 0.00055 0.81978 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD2_0.001_in 0.001 0.8186 0.00044 0.81948 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD2_0.01_in 0.01 0.81858 0.00050 0.81958 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD2_0.1_in 0.1 0.79073 0.00046 0.79165 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD2_0.5_in 0.5 0.73649 0.00048 0.73745 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD2_1_in 1.0 0.72283 0.00058 0.72399 Interspersed Moderation Only VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD3_0.0001_in 0.0001 0.82045 0.00049 0.82143 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD3_0.001_in 0.001 0.81985 0.00045 0.82075 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD3_0.01_in 0.01 0.81931 0.00052 0.82035 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD3_0.1_in 0.1 0.81562 0.00053 0.81668 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD3_0.5_in 0.5 0.78985 0.00053 0.79091 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD3_1_in 1.0 0.76897 0.00046 0.76989 All Regions Flooded VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD4_0.0001_in 0.0001 0.82006 0.00047 0.82100 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD4_0.001_in 0.001 0.81903 0.00047 0.81997 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD4_0.01_in 0.01 0.81878 0.00047 0.81972 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD4_0.1_in 0.1 0.79253 0.00056 0.79365 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD4_0.5_in 0.5 0.78037 0.00054 0.78145 VP-55_1S_020_HAC_UO2F2_3x105_2149_850_FLD4_1_in 1.0 0.79930 0.00045 0.80020 6-258

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of H/U-235 on keff + 2 0.84 0.835 0.83 0.825 k-eff + 2 0.82 0.815 0.81 0.805 0.8 650 700 750 800 850 900 950 1000 H/U-235 Figure 6.6.5-13. Effect of Sphere Size (H/U-235) - 1S, 20-wt.% U-235, HAC Package Array Effect of Uranium Mass on keff + 2 0.85 0.8 0.75 0.7 k-eff + 2 0.65 0.6 0.55 0.5 0.45 50 550 1050 1550 2050 2550 H/U-235 Figure 6.6.5-14. Effect of Uranium Mass - 1S, 20-wt.% U-235, HAC Package Array 6-259

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Flooding Configurations on keff + 2 0.84 0.82 0.8 k-eff + 2 Inner Cavity 0.78 Outer Cavity 0.76 Interspersed 0.74 All Regions 0.72 0.0001 0.001 0.01 0.1 1 Water Volume Fraction Figure 6.6.5-15. Effect of Flooding Configuration - 1S, 20-wt.% U-235, HAC Package Array 6-260

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.3.2 Flooding-Adjusted Most Reactive Configuration As shown in Section 6.6.5.3.1, a fully flooded inner cavity with all other flooding regions as void (FLD1_1), an H/U-235 of 850 and a uranium mass of 2149 was the most reactive configuration.

This section reexamines the H/U-235 vs keff + 2 for the 1S cylinder package array under HAC with 20-wt.% U-235 enrichment for a fully flooded inner cavity with all other floodable regions void.

As shown in Table 6.6.5-20 and Table 6.6.5-21, an H/U-235 of 650 is the bounding H/U-235 configuration given a fully flooded interior cavity with all other flooding regions void. The most reactive case for the 20-wt.% U-235 1S cylinder HAC package array evaluation, VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_650_in, with keff + 2 of 0.83413, is highlighted in both tables. Figure 6.6.5-16 and Figure 6.6.5-17 plot these trends for visual inspection. The uranium mass sensitivity study was not reexamined, as there is a clear and marked, independent effect in reducing uranium mass established in Section 6.6.5.3.1, and the other flooding configuration studies all resulted in significant reductions in keff.

Table 6.6.5-20. Effect of H/U-235 on keff for FLD1_1 - 1S, 20-wt.% U-235, HAC Package Array Case H/U-235 keff keff + 2 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_500_in 500 0.82663 0.00057 0.82777 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_550_in 550 0.83008 0.00047 0.83102 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_600_in 600 0.83088 0.0005 0.83188 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_650_in 650 0.83307 0.00053 0.83413 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_700_in 700 0.83039 0.00055 0.83149 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_750_in 750 0.82784 0.00047 0.82878 Table 6.6.5-21. Effect of FLD1 on keff for H/U-235 of 650 - 1S, 20-wt.% U-235, HAC Package Array Volume Case keff keff + 2 Fraction VP-55_1S_020_HAC_UO2F2_3x105_2149_650_FLD1_0.0001_in 0.0001 0.81255 0.00058 0.81371 VP-55_1S_020_HAC_UO2F2_3x105_2149_650_FLD1_0.001_in 0.001 0.81197 0.0006 0.81317 VP-55_1S_020_HAC_UO2F2_3x105_2149_650_FLD1_0.01_in 0.01 0.81307 0.00048 0.81403 VP-55_1S_020_HAC_UO2F2_3x105_2149_650_FLD1_0.1_in 0.1 0.81855 0.0005 0.81955 VP-55_1S_020_HAC_UO2F2_3x105_2149_650_FLD1_0.5_in 0.5 0.82399 0.00049 0.82497 VP-55_1S_020_HAC_UO2F2_3x105_2149_650_FLD1_1_in 1.0 0.83307 0.00053 0.83413 6-261

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of H/U-235 on keff + 2 0.85 0.845 0.84 0.835 k-eff + 2 0.83 0.825 0.82 0.815 0.81 450 500 550 600 650 700 750 800 H/U-235 Figure 6.6.5-16. Effect of Sphere Size (H/U-235) for FLD1_1 - 1S, 20-wt.% U-235, HAC Package Array Effect of Flooding Configuration on keff + 2 0.84 0.835 0.83 k-eff + 2 0.825 0.82 0.815 0.81 0.0001 0.001 0.01 0.1 1 Water Volume Fraction Figure 6.6.5-17. Effect of FLD1 for H/U-235 of 650 - 1S, 20-wt.% U-235, HAC Package Array 6-262

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.3.3 Cylinder Positioning Sensitivity Study As shown in Table 6.6.5-22, modeling the 20-wt.% U-235 1S cylinder group with no centering in the inner cavity produces the bounding cylinder position for the HAC package array, with keff + 2 equivalent to 0.83413.

Table 6.6.5-22. Effect of Cylinder Group Positioning on keff - 1S, 20-wt.% U-235, HAC Package Array Case Centering keff keff + 2 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_650_in None 0.83307 0.00053 0.83413 Radial +

VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_650_POS_1_in 0.82130 0.00043 0.82173 Axial VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_650_POS_2_in Axial 0.81974 0.00060 0.82034 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_650_POS_3_in Radial 0.83256 0.00046 0.83302 6.6.5.3.4 Array Configuration As shown in Table 6.6.5-23, reducing or increasing the height of packages in the HAC package array, while modeling at least 100 packages to satisfy a CSI of 1.0, results in no statistically significant difference in keff + 2 between the 2x104 array and the 3x105 array. However, it does result in a statistically significant reduction in keff + 2 for a 4x100 array. The 2x104 results in a higher reactivity with keff + 2 of 0.83438, however, the 3x105 array result is used in the UF6 sensitivity study because it is the default array size, and the increase in keff from a 3x105 array to a 2x104 is statistically insignificant.

Table 6.6.5-23. Effect of Array Configuration on keff - 1S, 20-wt.% U-235, HAC Package Array Array Total EALF Case keff keff + 2 Height Packages (eV)

VP-55_1S_020_HAC_UO2F2_2x104_2149_FLD1_1_650 2 104 0.83348 0.00045 0.83438 3.94E-02 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_650_in 3 105 0.83307 0.00053 0.83413 3.94E-02 VP-55_1S_020_HAC_UO2F2_4x100_2149_FLD1_1_650 4 100 0.83018 0.00047 0.83112 3.94E-02 6-263

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.3.5 UF6 Fissile Solution Sensitivity Study As shown in Table 6.6.5-24 and Figure 6.6.5-18, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly for the 1S, 20-wt.% U-235, HAC package array evaluation.

Therefore, UO2F2 is the bounding fissile configuration for the 1S cylinders with 20-wt.% U-235 HAC package array evaluation.

As this study does not result in UF6 being more reactive than UO2F2, the case with an array size of 2x104 identified in Section 6.6.5.3.4, with keff + 2 of 0.83438, is the most reactive result for the 1S cylinder, 20-wt.% U-235, HAC package array evaluation.

Table 6.6.5-24. Effect of UF6 on keff - 1S, 20-wt.% U-235, HAC Package Array Case H/U-235 keff keff + 2 Uranyl Fluoride (UO2F2)

VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_500_in 500 0.82663 0.00057 0.82777 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_550_in 550 0.83008 0.00047 0.83102 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_600_in 600 0.83088 0.00050 0.83188 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_650_in 650 0.83307 0.00053 0.83413 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_700_in 700 0.83039 0.00055 0.83149 VP-55_1S_020_HAC_UO2F2_3x105_2149_FLD1_1_750_in 750 0.82784 0.00047 0.82878 Uranium Hexafluoride (UF6)

VP-55_1S_020_HAC_UF6_3x105_2149_FLD1_1_500_in 500 0.82229 0.00047 0.82323 VP-55_1S_020_HAC_UF6_3x105_2149_FLD1_1_600_in 600 0.82775 0.00050 0.82875 VP-55_1S_020_HAC_UF6_3x105_2149_FLD1_1_700_in 700 0.82672 0.00052 0.82776 VP-55_1S_020_HAC_UF6_3x105_2149_FLD1_1_800_in 800 0.82321 0.00047 0.82415 VP-55_1S_020_HAC_UF6_3x105_2149_FLD1_1_900_in 900 0.81742 0.00049 0.81840 VP-55_1S_020_HAC_UF6_3x105_2149_FLD1_1_1000_in 1000 0.81031 0.00046 0.81123 Effect of UF6 Fissile Solution on keff 0.84 0.835 0.83 k-eff + 2 0.825 UO2F2 0.82 UF6 0.815 0.81 400 500 600 700 800 900 1000 1100 H/U-235 Figure 6.6.5-18. Effect of UF6 on keff - 1S, 20-wt.% U-235, HAC Package Array 6-264

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.4 2S Cylinder, 20-wt.% U-235, HAC Package Array For the 20-wt.% U-235 2S cylinder HAC package array analysis, three (3) 2S cylinders were modeled with a maximum uranium mass of 1502 gU/cylinder. The following variables represent the most reactive 2S cylinder, 20-wt.% U-235, HAC package array configuration: the maximum uranium mass of 1502 gU/cylinder, H/U-235 of 700, 0.1 volume fraction flooding in the Versa-Pac inner cavity with all other regions dry, fissile sphere in the bottom corner of the Versa-Pac inner cavity, a 105-package array 3 packages tall, and fissile material in the form of UO2F2.

6.6.5.4.1 Most Reactive Cylinder Configuration In this study, several values of sphere size (H/U-235) and uranium mass were evaluated to determine the most reactive configuration. Table 6.6.5-25 and Table 6.6.5-26 show for 20-wt.%

U-235 2S cylinder HAC package array analysis that a value of H/U-235 of 700 and 3004 gU (the maximum of 1502 gU/cylinder) is the most reactive of these two variables. However, these cases modeled a flooding configuration of 0.0001 volume fraction H2O in all floodable regions (FLD4_0.0001). In Table 6.6.5-27, a fully flooded inner cavity with all other regions void (FLD1_0.1) produces the bounding cylinder configuration for H/U-235 of 700, with keff + 2 of 0.91529. This case, VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD1_0.1_in, is highlighted in Table 6.6.5-27. Figure 6.6.5-19 through Figure 6.6.5-21 plot these trends for visual inspection.

Because the bounding flooding configuration in Table 6.6.5-27 differs significantly from the flooding configuration modeled in Table 6.6.5-25 and Table 6.6.5-26, a second iteration of the most reactive configuration is examined in Section 6.3.1.2.2 using the new flooding configuration (FLD1_0.1).

Table 6.6.5-25. Effect of Sphere Size (H/U-235) on keff - 2S, 20-wt.% U-235, HAC Package Array Case H/U-235 keff keff + 2 VP-55_2S_020_HAC_UO2F2_3x105_3004_600_in 600 0.90641 0.00076 0.90793 VP-55_2S_020_HAC_UO2F2_3x105_3004_650_in 650 0.90938 0.00058 0.91054 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_in 700 0.91190 0.00045 0.91280 VP-55_2S_020_HAC_UO2F2_3x105_3004_750_in 750 0.91022 0.00062 0.91146 VP-55_2S_020_HAC_UO2F2_3x105_3004_800_in 800 0.90947 0.00059 0.91065 VP-55_2S_020_HAC_UO2F2_3x105_3004_850_in 850 0.90757 0.00049 0.90855 Table 6.6.5-26. Effect of Uranium Mass on keff - 2S, 20-wt.% U-235, HAC Package Array Uranium Mass Case [per cylinder] keff keff + 2 (g)

VP-55_2S_020_HAC_UO2F2_3x105_1000_700_in 1000 [500] 0.59047 0.00047 0.59141 VP-55_2S_020_HAC_UO2F2_3x105_2000_700_in 2000 [1000] 0.79613 0.00048 0.79709 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_in 3004 [1502] 0.91190 0.00045 0.91280 6-265

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.5-27. Effect of Flooding Configuration on keff - 2S, 20-wt.% U-235, HAC Package Array Volume Case keff keff + 2 Fraction Inner Cavity Flooded Only VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD1_0.0001_in 0.0001 0.91145 0.00048 0.91241 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD1_0.001_in 0.001 0.91155 0.00047 0.91249 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD1_0.01_in 0.01 0.91170 0.00043 0.91256 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD1_0.1_in 0.1 0.91413 0.00058 0.91529 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD1_0.5_in 0.5 0.90784 0.00047 0.90878 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD1_1_in 1.0 0.90387 0.00048 0.90483 Outer Cavity Flooded Only VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD2_0.0001_in 0.0001 0.91196 0.00053 0.91302 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD2_0.001_in 0.001 0.91126 0.00049 0.91224 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD2_0.01_in 0.01 0.90861 0.00050 0.90961 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD2_0.1_in 0.1 0.87966 0.00052 0.88070 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD2_0.5_in 0.5 0.81920 0.00052 0.82024 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD2_1_in 1.0 0.80296 0.00047 0.80390 Interspersed Moderation Only VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD3_0.0001_in 0.0001 0.91135 0.00047 0.91229 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD3_0.001_in 0.001 0.91026 0.00049 0.91124 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD3_0.01_in 0.01 0.91086 0.00049 0.91184 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD3_0.1_in 0.1 0.90649 0.00052 0.90753 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD3_0.5_in 0.5 0.87861 0.00055 0.87971 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD3_1_in 1.0 0.85715 0.00051 0.85817 All Regions Flooded VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD4_0.0001_in 0.0001 0.91190 0.00045 0.91280 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD4_0.001_in 0.001 0.91099 0.00050 0.91199 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD4_0.01_in 0.01 0.90858 0.00053 0.90964 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD4_0.1_in 0.1 0.87891 0.00052 0.87995 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD4_0.5_in 0.5 0.85726 0.00050 0.85826 VP-55_2S_020_HAC_UO2F2_3x105_3004_700_FLD4_1_in 1.0 0.87495 0.00054 0.87603 6-266

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of H/U-235 on keff + 2 0.93 0.925 0.92 0.915 k-eff + 2 0.91 0.905 0.9 0.895 0.89 550 600 650 700 750 800 850 900 H/U-235 Figure 6.6.5-19. Effect of Sphere Size (H/U-235) - 2S, 20-wt.% U-235, HAC Package Array Effect of Uranium Mass on keff + 2 0.95 0.9 0.85 0.8 k-eff + 2 0.75 0.7 0.65 0.6 0.55 0.5 400 600 800 1000 1200 1400 1600 H/U-235 Figure 6.6.5-20. Effect of Uranium Mass - 2S, 20-wt.% U-235, HAC Package Array 6-267

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Flooding Configurations on keff + 2 0.92 0.9 0.88 k-eff + 2 Inner Cavity 0.86 Outer Cavity 0.84 Interspersed 0.82 All Regions 0.8 0.0001 0.001 0.01 0.1 1 Water Volume Fraction Figure 6.6.5-21. Effect of Flooding Configuration - 2S, 20-wt.% U-235, HAC Package Array 6-268

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.4.2 Flooding-Adjusted Most Reactive Configuration As shown in Section 6.6.5.4.1, a flooded inner cavity with an H2O volume fraction of 0.1, with all other flooding regions as void (FLD1_0.1), an H/U-235 of 700, and a uranium mass of 3004 was the most reactive configuration. This section reexamines the H/U-235 vs keff + 2 for the 2S cylinder package array under HAC with 20-wt.% U-235 enrichment for a 0.1 volume fraction inner cavity with all other floodable regions void.

As shown in Table 6.6.5-28, an H/U-235 of 700 is also the bounding H/U-235 configuration given an H2O volume fraction of 0.1 in the inner cavity with all other flooding regions void. The most reactive case for the 20-wt.% U-235, 2S cylinder, HAC package array evaluation, VP-55_1S_

020_HAC_UO2F2_3x105_2149_FLD1_0.1_700_in, with keff + 2 of 0.91529, is highlighted.

Figure 6.6.5-22 plots this trend for visual inspection. The uranium mass sensitivity study was not reexamined, as there is a clear and marked, independent effect in reducing uranium mass established in Section 6.3.1.2.1. Also, because the same H/U-235 was the most reactive case with the new FLD1_0.1 configuration, it was not necessary to reexamine the flooding configuration.

Table 6.6.5-28. Effect of H/U-235 on keff for FLD1_0.1 - 2S, 20-wt.% U-235, HAC Package Array Case H/U-235 keff keff + 2 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_550_in 550 0.90681 0.00056 0.90793 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_600_in 600 0.91101 0.00054 0.91209 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_650_in 650 0.91367 0.00066 0.91499 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_700_in 700 0.91413 0.00058 0.91529 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_750_in 750 0.91327 0.00046 0.91419 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_800_in 800 0.91242 0.00049 0.91340 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_850_in 850 0.91076 0.00046 0.91168 Effect of H/U-235 on keff + 2 0.93 0.925 0.92 0.915 k-eff + 2 0.91 0.905 0.9 0.895 0.89 450 500 550 600 650 700 750 800 850 900 H/U-235 Figure 6.6.5-22. Effect of Sphere Size (H/U-235) for FLD1_1 - 2S, 20-wt.% U-235, HAC Package Array 6-269

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.4.3 Cylinder Positioning Sensitivity Study As shown in Table 6.6.5-29, modeling the 20-wt.% U-235 2S cylinder group with no centering produces the bounding cylinder position for the HAC package array, with keff + 2 equivalent to 0.91529.

Table 6.6.5-29. Effect of Cylinder Group Positioning on keff - 2S, 20-wt.% U-235, HAC Package Array Case Centering keff keff + 2 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_700_in None 0.91413 0.00058 0.91529 Radial +

VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_700_POS_1_in 0.89117 0.00048 0.89213 Axial VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_700_POS_2_in Axial 0.89088 0.00046 0.89180 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_700_POS_3_in Radial 0.91409 0.00056 0.91521 6.6.5.4.4 Array Configuration As shown in Table 6.6.5-30, reducing or increasing the height of packages in the HAC package array, while modeling at least 100 packages to satisfy a CSI of 1.0, results in no statistically significant difference in keff + 2 for a 2x104 array. However, it does result in a statistically significant reduction in keff + 2 for a 4x100 array. Therefore, a 3x105 array is the bounding array configuration for the 2S cylinders with 20-wt.% U-235 HAC package array evaluation.

Table 6.6.5-30. Effect of Array Configuration on keff - 2S, 20-wt.% U-235, HAC Package Array Array Total Case keff keff + 2 Height Packages VP-55_2S_020_HAC_UO2F2_2x104_3004_FLD1_0.1_700 2 104 0.91400 0.00057 0.91514 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_700_in 3 105 0.91413 0.00058 0.91529 VP-55_2S_020_HAC_UO2F2_4x100_3004_FLD1_0.1_700 4 100 0.91039 0.00054 0.91147 6-270

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.5.4.5 UF6 Fissile Solution Sensitivity Study As shown in Table 6.6.5-31 and Figure 6.6.5-23, modeling the uranium as UF6 instead of UO2F2 reduces keff + 2 significantly for the 2S, 20-wt.% U-235, HAC package array evaluation.

Therefore, UO2F2 is the bounding fissile configuration for 20-wt.% U-235 2S cylinders in the HAC package array evaluation.

Table 6.6.5-31. Effect of UF6 on keff - 2S, 20-wt.% U-235, HAC Package Array Cylinder Case Spacing keff keff + 2 (cm)

Uranyl Fluoride (UO2F2)

VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_550_in 550 0.90681 0.00056 0.90793 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_600_in 600 0.91101 0.00054 0.91209 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_650_in 650 0.91367 0.00066 0.91499 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_700_in 700 0.91413 0.00058 0.91529 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_750_in 750 0.91327 0.00046 0.91419 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_800_in 800 0.91242 0.00049 0.91340 VP-55_2S_020_HAC_UO2F2_3x105_3004_FLD1_0.1_850_in 850 0.91076 0.00046 0.91168 Uranium Hexafluoride (UF6)

VP-55_2S_020_HAC_UF6_3x105_3004_FLD1_0.1_500_in 500 0.89430 0.00055 0.89540 VP-55_2S_020_HAC_UF6_3x105_3004_FLD1_0.1_600_in 600 0.90826 0.00051 0.90928 VP-55_2S_020_HAC_UF6_3x105_3004_FLD1_0.1_700_in 700 0.91226 0.00046 0.91318 VP-55_2S_020_HAC_UF6_3x105_3004_FLD1_0.1_800_in 800 0.91089 0.00047 0.91183 VP-55_2S_020_HAC_UF6_3x105_3004_FLD1_0.1_900_in 900 0.90427 0.00057 0.90541 VP-55_2S_020_HAC_UF6_3x105_3004_FLD1_0.1_1000_in 1000 0.89574 0.00044 0.89662 Effect of UF6 Fissile Solution on keff 0.92 0.915 0.91 k-eff + 2 0.905 UO2F2 0.9 UF6 0.895 0.89 400 500 600 700 800 900 1000 1100 H/U-235 Figure 6.6.5-23. Effect of UF6 on keff - 2S, 20-wt.% U-235, HAC Package Array 6-271

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.6 High-Capacity Basket with Hydrogen-Limited Contents 6.6.6.1 Bounding CPVC Compound Analysis As discussed in Section 6.3.4.6.1, the bounding CPVC compounds are determined for the HAC array evaluation. First, the optimally moderated case with nominal CPVC compounds is determined. As shown in Table 6.6.6-1 and Figure 6.6.6-1, a UC Volume Fraction of 0.140 is bounding for the HAC array with nominal CPVC compound. Therefore, this fissile-moderator combination is used to determine the bounding CPVC compound.

Table 6.6.6-1. CPVC Compound Homogeneous Results - HAC Array Case VFUC keff + 2 01 1.000 0.71662 02 0.916 0.74920 03 0.800 0.77182 04 0.600 0.80525 05 0.400 0.83980 06 0.200 0.88129 07 0.180 0.88374 08 0.160 0.88656 09 0.140 0.88668 10 0.120 0.88468 11 0.100 0.87994 12 0.080 0.86922 13 0.060 0.84803 14 0.040 0.80109 0.9 0.88 0.86 0.84 0.82 keff + 2 0.8 0.78 0.76 0.74 0.72 0.7 0 0.2 0.4 0.6 0.8 1 Volume Fraction Uranium Carbide Figure 6.6.6-1. UC Volume Fraction vs. keff for Nominal CPVC Compounds - HAC Array 6-272

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 With the optimally moderated case determined, the Chlorine percent and density of the CPVC components are varied to determine the bounding values. As shown in Table 6.6.6-2 and Figure 6.6.6-2 for the HAC array, the maximum Chlorine percentage and the minimum density produce the largest keff. Therefore, the bounding CPVC composition for the HAC array models the maximum Chlorine percentage and the minimum density.

Table 6.6.6-2. Bounding CPVC Compound Chlorine and Density keff Evaluation - HAC Array Compound Chlorine Case Density Weight keff + 2 (g/cm3) Percent 1-1 60 0.88207 2-1 1.45 66 0.88736 3-1 72 0.89379 1-2 60 0.88102 2-2 1.48 66 0.88617 3-2 72 0.89283 1-3 60 0.87843 2-3 1.51 66 0.88642 3-3 72 0.89221 1-4 60 0.87855 2-4 1.54 66 0.88490 3-4 72 0.89147 0.896 0.892 0.888 keff + 2 1.45 g/cc 1.48 g/cc 0.884 1.51 g/cc 1.54 g/cc 0.880 0.876 58 60 62 64 66 68 70 72 74 Chlorine Weight Percent Figure 6.6.6-2. CPVC Compound Chlorine Percentage and Density vs. keff - HAC Array 6-273

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.6.2 Bounding Uranium Compound Homogeneous Analysis for CSI=1.4 Contents This analysis models four Uranium compounds to provide a comparison between Uranium carbides, fluorides, nitrides, and oxides and demonstrates that Uranium carbide is bounding for the CSI=1.4 configuration. Table 6.3.2-3 lists the compounds examined in this analysis. Uranium Oxycarbide (UCO) is a permissible content, but it is not specifically analyzed. Although abbreviated as UCO, implying a chemical formula, Uranium Oxycarbide is a blend of UO2 and UCx [7]. As both UC and UO2 are analyzed, UCO is not analyzed separately.

For this analysis, all cases model a HAC 2N=72 array of VP-55s. The moderator pipes and separator plate of the HCB model their respective bounding CPVC compounds, as listed in Section 6.3.2.11. The keff results for each compound are presented in Table 6.6.6-3 with their Volume Fraction Uranium Compound vs. keff curves plotted in Figure 6.6.6-3. As shown, Uranium Carbide bounds all Uranium compounds analyzed (i.e., carbides, fluorides, nitrides, and oxides).

Thus, UC is used as the overall bounding compound for the CSI=1.4 content.

In addition, the maximum result for UC listed in Table 6.6.6-3 is the bounding homogeneous configuration result for the CSI=1.4 contents. Therefore, a homogeneous UC-moderator mixture with unlimited UC contents and CSI=1.4 is acceptable in a HAC array.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.6-3. Bounding Uranium Compound Class Case Summary keff + 2 VFX 1 Carbides Fluorides Nitrides Oxides (UC) (UF3) (UN) (UO2) 1.000 0.71777 0.55786 0.70017 0.62555 0.916 0.75148 0.61534 0.73525 0.67135 0.800 0.77562 0.66029 0.76056 0.70598 0.600 0.80760 0.73106 0.79439 0.75872 0.400 0.84442 0.80047 0.83132 0.81522 0.200 0.88557 0.85096 0.87397 0.86597 0.180 0.88824 0.85174 0.87717 0.86908 0.160 0.88975 0.85079 0.88082 0.87078 0.140 0.89117 0.84807 0.88097 0.87026 0.120 0.89084 0.84067 0.88082 0.86720 0.100 0.88488 0.82844 0.87630 0.85929 0.080 0.87415 0.80606 0.86730 0.84289 0.060 0.85317 0.76910 0.84780 0.81330 0.040 0.80593 0.69790 0.80346 0.75390 1

Note: X is substituted for the respective uranium compound.

0.90 0.89 0.88 0.87 0.86 keff + 2 UC 0.85 UN 0.84 UO2 0.83 UF3 0.82 0.81 0.80 0 0.1 0.2 0.3 0.4 Volume Fraction Uranium Compound Figure 6.6.6-3. Volume Fraction of Bounding Uranium Compounds vs. keff 6-275

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.6.3 Uranium Oxide (U3O8) Homogeneous Analysis for CSI=0.7 Contents The compound U3O8 is selected as a separate content to maximize the array size for less reactive compounds. The moderator pipe and separator plates of the HCB model their respective bounding CPVC compositons, as presented in Section 6.3.2.11. The results of the analysis show that UO3 and UF4 both have a peak keff less than that of U3O8, with each peak case highlighted in Table 6.6.6-4 and with the VFX vs. keff trends plotted in Figure 6.6.6-4. As U3O8 bounds UO3 and UF4, these compounds are allowable with the lower CSI determined for U3O8.

In the next study, homogeneous U3O8 contents are re-analyzed for the HAC array with a decreased CSI=0.7, as the previous study analyzed a HAC array with CSI=1.4 for comparative purposes. The HAC array homogeneous evaluation results for U3O8 with CSI=0.7 are shown in Table 6.6.6-5, with the peak case highlighted, and the keff results are plotted vs. Volume Fraction U3O8 in Figure 6.6.6-5. For the U3O8 contents, the peak in the VFX vs. keff curve has been captured, thus, the optimally moderated configuration has been analyzed and is below the USL.

Therefore, unlimited U3O8 homogeneous contents in a HAC array with CSI=0.7 are acceptable.

Table 6.6.6-4. Uranium Compounds Bounded by U3O8 Case Summary (CSI=1.4) keff + 2 VFX 1 U3O8 UF4 UO3 1.000 0.53278 0.46907 0.49329 0.916 0.58711 0.53395 0.55136 0.800 0.63367 0.59106 0.60342 0.600 0.70946 0.68416 0.68873 0.400 0.78516 0.76912 0.77174 0.200 0.84248 0.81982 0.82979 0.180 0.84383 0.81898 0.83072 0.160 0.84359 0.81523 0.82872 0.140 0.84183 0.80857 0.82537 0.120 0.83363 0.79747 0.81611 0.100 0.82263 0.77923 0.80323 0.080 0.80034 0.75061 0.77890 0.060 0.76268 0.70256 0.73543 0.040 0.69284 0.62033 0.65989 Note: 1 X is substituted for a given uranium compound.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.6.6-5. HAC Array 20-wt.% 235U U3O8 Homogeneous Case Summary (CSI=0.7)

Case VFU3O8 keff + 2 01 1.000 0.60173 02 0.916 0.65716 03 0.800 0.70149 04 0.600 0.77520 05 0.400 0.84843 06 0.200 0.90135 07 0.180 0.90311 08 0.160 0.90093 09 0.140 0.89710 10 0.120 0.88963 11 0.100 0.87492 12 0.080 0.85161 13 0.060 0.81012 14 0.040 0.73449 0.85 0.84 0.83 0.82 0.81 keff + 2 0.8 U3O8 0.79 UF4 0.78 UO3 0.77 0.76 0.75 0 0.1 0.2 0.3 0.4 Volume Fraction Uranium Compound Figure 6.6.6-4. Comparison of UF4 and UO3 with U3O8 vs. keff - CSI=1.4 6-277

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.92 0.9 0.88 keff + 2 0.86 0.84 0.82 0.8 0 0.1 0.2 0.3 0.4 0.5 0.6 Volume Fraction Uranium Oxide Figure 6.6.6-5. HAC Array Homogeneous Volume Fraction U3O8 vs. keff - CSI=0.7 6-278

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.6.6.4 Heterogeneous Evaluation As stated in Section 6.3.4.6, a range of particle sizes and pitches (i.e., H/X ratio) were evaluated to determine the bounding configuration. The moderator pipe and separator plates of the HCB model their respective bounding CPVC compositions, presented in Section 6.3.2.11. The results of the HAC array heterogeneous content studies for UC and U3O8 are listed in Table 6.6.6-6 and Table 6.6.6-7, respectively. These results are plotted with their respective homogeneous results in Figure 6.6.6-6 and Figure 6.6.6-7 for comparison. The results show that heterogeneous particles bound homogeneous for both UC and U3O8 contents and the USL is not exceeded for either content. Note that several of the keff curves in the figures have atypical behavior, i.e.,

multiple peaks in keff. This is due to the heterogeneous modeling of the fissile material. For larger particles, as the pitch is increased, larger quantities of fissile material are removed at the boundary of the 5-inch pipe as the pitch is expanded. This results in the seemingly atypical behavior of the dips in the keff curves for the larger particles.

Table 6.6.6-6. HAC Array Heterogeneous Case Summary - UC 20-wt.% 235U (CSI=1.4)

Pitch keff + 2 for Particle Radius (cm)

Case Ratio 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 x_1 2.4 0.87271 0.87867 0.88249 0.88825 0.89070 0.89371 0.89455 0.89530 0.89624 0.90129 x_2 2.6 0.88790 0.89442 0.90038 0.90386 0.90434 0.90761 0.90722 0.90896 0.90698 0.90494 x_3 2.7 0.89455 0.90080 0.90567 0.90656 0.91175 0.90930 0.90715 0.90670 0.91066 0.89804 x_4 2.8 0.89757 0.90370 0.90915 0.91254 0.91133 0.90974 0.91116 0.90459 0.90428 0.90179 x_5 2.9 0.90075 0.90744 0.90940 0.91126 0.91024 0.91314 0.91117 0.90363 0.89607 0.90379 x_6 3.0 0.90290 0.90894 0.91231 0.90963 0.91190 0.90810 0.90414 0.90365 0.88605 0.89204 x_7 3.1 0.90375 0.90895 0.90847 0.91004 0.90849 0.89769 0.89555 0.89624 0.88524 0.87768 x_8 3.2 0.90283 0.90722 0.90780 0.90540 0.90042 0.89502 0.88512 0.87896 0.88259 0.86198 x_9 3.4 0.89780 0.89991 0.89855 0.89543 0.88783 0.88203 0.87557 0.85544 0.85239 0.83263 1

Note: x stands for a case identifier corresponding to the particle size (e.g., case 1 has a particle size of 0.05 cm).

Table 6.6.6-7. HAC Array Heterogeneous Case Summary - U3O8 20-wt.% 235U (CSI=0.7)

Pitch keff + 2 for Particle Radius (cm)

Case Ratio 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 x_1 2.4 0.88521 0.88944 0.89415 0.89735 0.89829 0.89780 0.90042 0.89981 0.89844 0.90268 x_2 2.6 0.90180 0.90864 0.91129 0.91293 0.91098 0.91246 0.91128 0.91155 0.90863 0.90409 x_3 2.7 0.90701 0.91118 0.91287 0.91234 0.91580 0.91138 0.90807 0.90808 0.90973 0.89627 x_4 2.8 0.90858 0.91276 0.91429 0.91635 0.91334 0.91045 0.91058 0.90123 0.90046 0.89772 x_5 2.9 0.90896 0.91233 0.91303 0.91258 0.91019 0.91098 0.90676 0.89761 0.88898 0.89615 x_6 3.0 0.90834 0.91084 0.91117 0.90738 0.90579 0.90114 0.89623 0.89531 0.87675 0.88182 x_7 3.1 0.90482 0.90595 0.90500 0.90297 0.89782 0.88780 0.88439 0.88270 0.87289 0.86137 x_8 3.2 0.89844 0.90036 0.89870 0.89324 0.88731 0.88251 0.87007 0.86314 0.86830 0.84328 x_9 3.4 0.88560 0.88538 0.88048 0.87548 0.86710 0.85962 0.85374 0.83448 0.82935 0.81064 1

Note: x stands for a case identifier corresponding to the particle size (e.g., case 1 has a particle size of 0.05 cm).

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.920 0.915 0.910 0.05 0.1 0.905 0.15 0.900 0.2 keff + 2 0.895 0.25 0.3 0.890 0.35 0.885 0.4 0.880 0.45 0.875 0.5 Hom.

0.870 0.07 0.12 0.17 0.22 0.27 0.32 Volume Fraction UC Figure 6.6.6-6. HAC Array Heterogeneous Volume Fraction UC vs. keff 0.920 0.915 0.910 0.05 0.1 0.905 0.15 0.900 0.2 keff + 2 0.895 0.25 0.3 0.890 0.35 0.885 0.4 0.880 0.45 0.875 0.5 Hom.

0.870 0.07 0.12 0.17 0.22 0.27 0.32 Volume Fraction U3O8 Figure 6.6.6-7. HAC Array Heterogeneous Volume Fraction U3O8 vs. keff 6-280

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 The flooding study uses the respective maximum cases of the heterogeneous study (i.e., the bounding particle radius and pitch). The results of the flooding studies for UC and U3O8 are shown in Table 6.6.6-8 and Table 6.6.6-9, respectively, with the trends plotted in Figure 6.6.6-8 and Figure 6.6.6-9, respectively. Results show that any additional flooding results in no statistically significant increase in keff over the baseline flooding configuration, thus, keff remains less than the USL for both UC and U3O8. Therefore, the bounding flooding configuration has been determined.

Table 6.6.6-8. HAC Array 20-wt.% UC (CSI=1.4) Flooding Study Results keff + 2 for Flooding Configurations Flooding Interspersed Case Inner Cavity Outer Cavity All Regions H2O VF Moderation (FLD1) (FLD2) (FLD4)

(FLD3)

FLDx_1 0.0001 0.91377 0.91354 0.91297 0.91314a FLDx_2 0.001 0.91346 0.91267 0.91360 0.91297 FLDx_3 0.01 0.91080 0.90853 0.91411 0.90451 FLDx_4 0.1 0.87724 0.84165 0.90349 0.80282 FLDx_5 0.5 0.77736 0.71678 0.84417 0.72436 FLDx_6 1 0.74924 0.68879 0.79939 0.73001 Note: 1 This is the flooding configuration of the baseline heterogeneous case.

Table 6.6.6-9. HAC Array 20-wt.% U3O8 (CSI=0.7) Flooding Study Results keff + 2 for Flooding Configurations Flooding Interspersed Case Inner Cavity Outer Cavity All Regions H2O VF Moderation (FLD1) (FLD2) (FLD4)

(FLD3)

FLDx_1 0.0001 0.91676 0.91562 0.91695 0.91635a FLDx_2 0.001 0.91571 0.91575 0.91605 0.91489 FLDx_3 0.01 0.91190 0.90907 0.91554 0.90164 FLDx_4 0.1 0.86057 0.81552 0.89842 0.76446 FLDx_5 0.5 0.73293 0.66785 0.81663 0.67298 FLDx_6 1 0.69982 0.63546 0.76180 0.67859 1

Note: This is the flooding configuration of the baseline heterogeneous case.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 0.95 0.9 0.85 keff + 2 FLD1 0.8 FLD2 0.75 FLD3 FLD4 0.7 0.65 0.0001 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.6-8. Flooding Study UC (CSI=1.4) Flooding Volume Fraction vs. keff 0.95 0.9 0.85 0.8 keff + 2 FLD1 0.75 FLD2 FLD3 0.7 FLD4 0.65 0.6 0.0001 0.001 0.01 0.1 1 Flooding Volume Fraction Figure 6.6.6-9. Flooding Study U3O8 (CSI=0.7) Flooding Volume Fraction vs. keff 6-282

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Finally, as described in Section 6.3.4.6, three different configurations of the HCB are analyzed.

The first case displaces each 5-inch pipe out of its respective moderator pipe, thus, outside of the moderator/separator region to determine the effect on keff (Pipe Up case). The second and third cases (No HCB Plate and No HCB Pipe cases) are done to demonstrate that the moderator pipes and the separator plate of the HCB can be classified as Category B safety items. This is done by showing that keff will remain below the USL if either the separator plate or one of the two moderator pipes are removed from the model (i.e., replaced with the bounding flooding configuration).

Results for both the UC and U3O8 HAC array HCB studies are shown in Table 6.6.6-10. As the results show, keff decreases when the 5-inch pipes are displaced outside of the HCB. The effect of displacing a 5-inch pipe out of the moderator pipe is counter-acted by the effect of centering the fissile material in each package, thus, increasing the distance between fissile regions in adjacent packages. Second, keff increases upon removal of the separator plate or a moderator pipe but keff remains less than the USL for both, thus, acceptable in the HAC array. Therefore, it is acceptable to classify these components as Category B safety items.

Table 6.6.6-10. HCB Study Results - HAC Array keff + 2 (keff + 2)

Case UC U3O8 UC U3O8 (CSI=1.4) (CSI=0.7) (CSI=1.4) (CSI=0.7)

Baseline 0.91314 0.91635 -- --

Pipe Up 0.91027 0.91236 -0.00287 -0.00399 No HCB Plate 0.92470 0.93177 0.01156 0.01542 One HCB Pipe 0.92800 0.93882 0.01486 0.02247 6-283

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.7 Fissile Material Packages for Air Transport 6.7.1 Configuration The Versa-Pac packaging has not been subjected to the expanded accident conditions specified in 10 CFR 71.55(f). Thus, it is considered that, for an air transport accident, all fissile contents escape the Versa-Pac and form an optimally moderated sphere of material that is closely reflected by 20 cm of water. To bound the allowable contents of the Versa-Pac listed in Section 6.2, the fissile material considered is a Uranium metal at a density of 19.05 g/cm3. The moderating material of the spherical mass is high-density polyethylene (HDPE) as described in Section 6.3.2.5. Subcriticality of the system is demonstrated through H/U-235 calculations and sensitivity studies, as outlined in Section 6.7.2.

6.7.2 Results A limiting U-235 mass is set for each enrichment. For the VP-55 and VP-110, this analysis verifies that the ground transportation U-235 mass limits are acceptable for air transport, as the ground transportation U-235 mass limits are less than the VP-55 with 5-inch pipe air transport limits determined in this section. Therefore, the maximum VP-55 and VP-110 U-235 mass for air transport is equivalent to the ground transportation VP-55 and VP-110 U-235 mass limits.

For the VP-55 with 5-inch pipe container configuration, the U-235 mass limits for air transport are set by the maximum allowable quantities determined in this analysis. It is demonstrated that air transport of a VP-55 with 5-inch pipe, when shipping these quantities, is safe through the sensitivity studies provided below. The 5-inch pipe U-235 mass limit for each of the enrichments is:

• 395 g U-235 for enrichments up to 100 wt.%.

• 495 g U-235 for enrichments up to 20 wt.%.

• 590 g U-235 for enrichments up to 10 wt.%.

• 790 g U-235 for enrichments up to 5 wt.%.

6.7.2.1 H/U-235 Ratio Safe U-235 limits for air transport for each enrichment are determined by generating H/U-235 curves for increasing U-235 masses until the USL is approached. This was repeated for each enrichment. The resulting H/U-235 curves for the limiting masses are provided in Table 6.7-1 and Figure 6.7-1. Figure 6.7-2 shows the H/U-235 curves for each U-235 mass and each enrichment.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.7-1. Air Transport H/U-235 Variation Results Case H/U-235 keff keff + 2 395 g U-235 at 100-wt.% U-235 Enrichment VP_AIR_POLY_100WT_375_in 3.75E+02 0.92552 0.00042 0.92636 VP_AIR_POLY_100WT_425_in 4.25E+02 0.93265 0.00048 0.93361 VP_AIR_POLY_100WT_475_in 4.75E+02 0.93502 0.00043 0.93588 VP_AIR_POLY_100WT_525_in 5.25E+02 0.93635 0.0004 0.93715 VP_AIR_POLY_100WT_575_in 5.75E+02 0.93527 0.00038 0.93603 VP_AIR_POLY_100WT_625_in 6.25E+02 0.93214 0.00046 0.93306 VP_AIR_POLY_100WT_675_in 6.75E+02 0.92914 0.00048 0.9301 495 g U-235 at 20-wt.% U-235 Enrichment VP_AIR_POLY_020WT_400_in 4.00E+02 0.92728 0.00039 0.92806 VP_AIR_POLY_020WT_450_in 4.50E+02 0.93394 0.00044 0.93482 VP_AIR_POLY_020WT_500_in 5.00E+02 0.93601 0.00048 0.93697 VP_AIR_POLY_020WT_550_in 5.50E+02 0.93693 0.00038 0.93769 VP_AIR_POLY_020WT_600_in 6.00E+02 0.93598 0.00041 0.9368 VP_AIR_POLY_020WT_650_in 6.50E+02 0.93307 0.00055 0.93417 VP_AIR_POLY_020WT_700_in 7.00E+02 0.92967 0.0004 0.93047 590 g U-235 at 10-wt.% U-235 Enrichment VP_AIR_POLY_010WT_400_in 4.00E+02 0.92689 0.0005 0.92789 VP_AIR_POLY_010WT_450_in 4.50E+02 0.93281 0.0004 0.93361 VP_AIR_POLY_010WT_500_in 5.00E+02 0.93657 0.00037 0.93731 VP_AIR_POLY_010WT_550_in 5.50E+02 0.93732 0.00038 0.93808 VP_AIR_POLY_010WT_600_in 6.00E+02 0.93571 0.00039 0.93649 VP_AIR_POLY_010WT_650_in 6.50E+02 0.9333 0.00039 0.93408 VP_AIR_POLY_010WT_700_in 7.00E+02 0.93028 0.00039 0.93106 790 g U-235 at 5-wt.% U-235 Enrichment VP_AIR_POLY_005WT_425_in 4.25E+02 0.92903 0.00039 0.92981 VP_AIR_POLY_005WT_475_in 4.75E+02 0.9336 0.0005 0.9346 VP_AIR_POLY_005WT_525_in 5.25E+02 0.93623 0.00042 0.93707 VP_AIR_POLY_005WT_575_in 5.75E+02 0.93583 0.00045 0.93673 VP_AIR_POLY_005WT_625_in 6.25E+02 0.93451 0.00037 0.93525 VP_AIR_POLY_005WT_675_in 6.75E+02 0.93183 0.00039 0.93261 VP_AIR_POLY_005WT_725_in 7.25E+02 0.92731 0.00042 0.92815 6-285

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of H/U-235 on keff + 2 for U-235 Mass Limits 0.939 0.937 0.935 k-eff + 2 0.933 U(100) 0.931 U(20) 0.929 U(10) 0.927 U(5) 0.925 350 450 550 650 750 H/U-235 Figure 6.7-1. Air Transport H/U-235 Curve for Each Enrichment and Mass Limit 6-286

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 U(100) U(20) 0.95 0.95 0.9 0.9 0.85 0.85 0.8 100 g 125 g 0.8 k-eff + 2 k-eff + 2 200 g 250 g 0.75 375 g 300 g 0.75 0.7 495 g 395 g 0.7 0.65 0.6 0.65 0.55 0.6 200 400 600 800 1000 200 400 600 800 1000 H/U-235 H/U-235 U(10) U(5) 0.95 0.95 0.9 0.9 0.85 0.85 150 g 200 g 0.8 0.8 k-eff + 2 k-eff + 2 300 g 400 g 450 g 600 g 0.75 0.75 590 g 790 g 0.7 0.7 0.65 0.65 0.6 0.6 200 400 600 800 1000 200 400 600 800 1000 H/U-235 H/U-235 Figure 6.7-2. Air Transport H/U-235 Curves for Mass Limit Determinations of Each Enrichment 6-287

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.7.2.2 Moderating Material To verify that having the HDPE plastic as the moderating material results in the worst-case configuration, two other potential moderating materials are considered. These materials are water and the polyurethane foam used for thermal protection in the Versa-Pac. The results of the study replacing the HDPE moderator with water are provided in Table 6.7-2 and Figure 6.7-3. From these results, the HDPE material results in a more reactive configuration.

Table 6.7-2. Air Transport Water Moderation Results Case H/U-235 keff keff + 2 395 g U-235 - U(100)

VP_AIR_H2O_100WT_400_in 4.00E+02 0.83357 0.00041 0.83439 VP_AIR_H2O_100WT_450_in 4.50E+02 0.83844 0.00042 0.83928 VP_AIR_H2O_100WT_500_in 5.00E+02 0.84138 0.00052 0.84242 VP_AIR_H2O_100WT_550_in 5.50E+02 0.84171 0.00041 0.84253 VP_AIR_H2O_100WT_600_in 6.00E+02 0.84052 0.00051 0.84154 VP_AIR_H2O_100WT_650_in 6.50E+02 0.83851 0.00041 0.83933 VP_AIR_H2O_100WT_700_in 7.00E+02 0.83529 0.00039 0.83607 495 g U-235 - U(20)

VP_AIR_H2O_020WT_400_in 4.00E+02 0.84028 0.00046 0.8412 VP_AIR_H2O_020WT_450_in 4.50E+02 0.84532 0.00051 0.84634 VP_AIR_H2O_020WT_500_in 5.00E+02 0.84909 0.0004 0.84989 VP_AIR_H2O_020WT_550_in 5.50E+02 0.85051 0.00039 0.85129 VP_AIR_H2O_020WT_600_in 6.00E+02 0.84993 0.00037 0.85067 VP_AIR_H2O_020WT_650_in 6.50E+02 0.84878 0.00047 0.84972 VP_AIR_H2O_020WT_700_in 7.00E+02 0.8462 0.00039 0.84698 590 g U-235 - U(10)

VP_AIR_H2O_010WT_400_in 4.00E+02 0.84592 0.00042 0.84676 VP_AIR_H2O_010WT_450_in 4.50E+02 0.85186 0.00042 0.8527 VP_AIR_H2O_010WT_500_in 5.00E+02 0.85512 0.00044 0.856 VP_AIR_H2O_010WT_550_in 5.50E+02 0.85559 0.00038 0.85635 VP_AIR_H2O_010WT_600_in 6.00E+02 0.85594 0.00046 0.85686 VP_AIR_H2O_010WT_650_in 6.50E+02 0.85404 0.00037 0.85478 VP_AIR_H2O_010WT_700_in 7.00E+02 0.85167 0.00037 0.85241 790 g U-235 - U(5)

VP_AIR_H2O_005WT_400_in 4.00E+02 0.85504 0.00043 0.8559 VP_AIR_H2O_005WT_450_in 4.50E+02 0.8603 0.00041 0.86112 VP_AIR_H2O_005WT_500_in 5.00E+02 0.86369 0.00043 0.86455 VP_AIR_H2O_005WT_550_in 5.50E+02 0.86486 0.00049 0.86584 VP_AIR_H2O_005WT_600_in 6.00E+02 0.86509 0.0004 0.86589 VP_AIR_H2O_005WT_650_in 6.50E+02 0.86342 0.00036 0.86414 VP_AIR_H2O_005WT_700_in 7.00E+02 0.86116 0.00037 0.8619 6-288

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of Water Moderator on keff + 2 for U-235 Mass Limits 0.87 0.865 0.86 0.855 k-eff + 2 395 g U(100) 0.85 495 g U(20) 0.845 0.84 590 g U(10) 0.835 790 g U(5) 0.83 350 450 550 650 750 H/U-235 Figure 6.7-3. Air Transport Water Moderation Results The specification for the polyurethane foam is provided in Section 1.4.3. In this section, a requirement for the polyurethane foam is that it has a lower hydrogen density than water. With this requirement and the lower density of the foam (11 pcf, 0.176 g/cm3), the polyurethane foam as a moderating material would result in a less reactive system and is bounded by the HDPE as a moderator.

6.7.2.3 Polyethylene Density Reduction An additional study was performed to demonstrate that the HDPE material modeled is bounding of lower density polyethylene plastic materials. The results of this study are provided in Table 6.7-3 and Figure 6.7-4. From these results, it is clear that the HDPE material is bounding of lower density polyethylene.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.7-3. Air Transport HDPE Density Variation Results HDPE Density Case H/U-235 keff keff + 2 (g/cm3) 395 g U-235 at 100-wt.% Uranium Enrichment VP_AIR_POLY_100WT_RD_1_in 0.5 2.68E+02 0.64662 0.00038 0.64738 VP_AIR_POLY_100WT_RD_2_in 0.6 3.21E+02 0.72229 0.00039 0.72307 VP_AIR_POLY_100WT_RD_3_in 0.7 3.75E+02 0.78927 0.00042 0.79011 VP_AIR_POLY_100WT_RD_4_in 0.8 4.29E+02 0.84956 0.00043 0.85042 VP_AIR_POLY_100WT_RD_5_in 0.9 4.82E+02 0.90137 0.00047 0.90231 VP_AIR_POLY_100WT_525_in 0.98 5.25E+02 0.93635 0.0004 0.93715 495 g U-235 at 20-wt.% Uranium Enrichment VP_AIR_POLY_020WT_RD_1_in 0.5 2.81E+02 0.66259 0.0004 0.66339 VP_AIR_POLY_020WT_RD_2_in 0.6 3.37E+02 0.73666 0.00045 0.73756 VP_AIR_POLY_020WT_RD_3_in 0.7 3.93E+02 0.80092 0.00044 0.8018 VP_AIR_POLY_020WT_RD_4_in 0.8 4.49E+02 0.85718 0.00057 0.85832 VP_AIR_POLY_020WT_RD_5_in 0.9 5.05E+02 0.90473 0.00039 0.90551 VP_AIR_POLY_020WT_550_in 0.98 5.50E+02 0.93693 0.00038 0.93769 590 g U-235 at 10-wt.% Uranium Enrichment VP_AIR_POLY_010WT_RD_1_in 0.5 2.81E+02 0.67607 0.0004 0.67687 VP_AIR_POLY_010WT_RD_2_in 0.6 3.37E+02 0.74732 0.00039 0.7481 VP_AIR_POLY_010WT_RD_3_in 0.7 3.93E+02 0.8085 0.0004 0.8093 VP_AIR_POLY_010WT_RD_4_in 0.8 4.49E+02 0.86287 0.00041 0.86369 VP_AIR_POLY_010WT_RD_5_in 0.9 5.05E+02 0.90687 0.00042 0.90771 VP_AIR_POLY_010WT_550_in 0.98 5.50E+02 0.93732 0.00038 0.93808 790 g U-235 at 5-wt.% Uranium Enrichment VP_AIR_POLY_005WT_RD_1_in 0.5 2.68E+02 0.69184 0.00044 0.69272 VP_AIR_POLY_005WT_RD_2_in 0.6 3.21E+02 0.75945 0.00046 0.76037 VP_AIR_POLY_005WT_RD_3_in 0.7 3.75E+02 0.81807 0.00041 0.81889 VP_AIR_POLY_005WT_RD_4_in 0.8 4.29E+02 0.86683 0.00042 0.86767 VP_AIR_POLY_005WT_RD_5_in 0.9 4.82E+02 0.90827 0.0004 0.90907 VP_AIR_POLY_005WT_525_in 0.98 5.25E+02 0.93623 0.00042 0.93707 6-290

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Effect of HDPE Density Reduction on keff + 2 for U-235 Mass Limits 0.99 0.94 0.89 k-eff + 2 0.84 395 g U(100) 0.79 495 g U(20) 0.74 590 g U(10) 0.69 790 g U(5) 0.64 250 300 350 400 450 500 550 H/U-235 Figure 6.7-4. Air Transport HDPE Density Results 6-291

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.8 Benchmark Evaluations The following is a simplified procedure for benchmarking evaluation used to generate USL equations for the Versa-Pac criticality safety analysis. This procedure follows that of a standard benchmarking analysis using the methods discussed in Section 4 of NUREG/CR-6361 [8] with the USLSTATS code, with one additional step to provide a quantitative assessment of benchmark applicability.

1. Use standard qualitative criteria (e.g. fissile/moderating/structural materials, moderation ratio, configuration) to select a large number of benchmarks and develop a suite of benchmark cases applicable to the Versa-Pac. All benchmarks are modeled and keff is calculated using the SCALE6.1.3 CSAS6 code and ce_v7_endf continuous energy cross section library to match the Versa-Pac criticality calculations.

2. Perform a quantitative assessment of the similarity of the benchmarks to the Versa-Pac criticality models for each enrichment band using the SCALE TSUNAMI modules and the ck correlation coefficient. The application cases used for comparison are from the Standard Versa-Pac configuration (see Sections 6.5.1 and 6.6.1) and only the benchmark cases with the highest ck values are selected for the generation of the USL equation at each enrichment.

3. Perform a trending analysis with the USLSTATS code to generate a USL equation for each enrichment based on the traditional trending parameters (e.g., H/X, EALF) with the highest correlation to keff. Note: For all enrichments other than 20 wt% HCB (where EALF has the highest correlation), the parameter with the highest correlation is the H/X ratio.

4. The USL equations are applied each analysis to determine a USL for each, individually, based on the trending parameter value of the bounding case (see Section 6.1.2.7).

6.8.1 Applicability of Benchmark Experiments Table 6.8.1-1 summarizes the 264 critical benchmark experiments that were selected as applicable to the Versa-Pac criticality analysis and included in the benchmarking suite. All benchmarks are from the International Handbook of Criticality Safety Benchmark Experiments (ICSBEP handbook) [9], based on qualitative selection criteria. As the Versa-Pac is designed to transport uranium across the full range of enrichments, benchmarks across all enrichment ranges (i.e. HEU, IEU, and LEU) were selected for the validation. Benchmarks with water and hydrocarbon (e.g. polyethylene) moderators and reflectors and primarily metallic structural materials were selected to match the moderating materials in the Versa-Pac application cases.

Additionally, as no neutron absorbing poisons are credited in the Versa-Pac analyses, no benchmarks with neutron absorbers were selected. A large range of moderation ratios (H/X) were selected to cover the ranges of the cases analyzed. As noted in Table 6.8.1-1, four benchmark series were added to accommodate an extended USL equation for the 10 wt% enrichment, to support the lower H/X value in the 5-inch pipe hydrogen limited content analysis. Two additional series with higher EALF values were added to accommodate an extended USL equation for the 20 wt% 235U enrichment HCB hydrogen-limited content analysis. Each benchmark selected was modeled and analyzed using the SCALE 6.1.3 CSAS6 module to calculate keff, s, and EALF. For benchmarks with homogeneous mixtures, H/X was taken directly from the SCALE output mixing table, but for any heterogeneous systems (e.g. fuel rods in water), the H/X ratio is calculated based on the geometry and fuel/moderator compositions. The EALF, H/X, and combined values for keff and s for each benchmark case are listed in Table 6.8.1-2. For the combined values, keff is normalized by the expected value of keff for the experiment (typically 1.0) and s is the combined uncertainty from the benchmark data and CSAS calculation.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 For a quantitative determination of the applicability of the benchmarks for each enrichment analyzed, the SCALE TSUNAMI modules were used to determine the degree of similarity between the application cases (i.e. Versa-Pac models at each enrichment) and benchmarks. This was accomplished by converting the SCALE CSAS6 models to TSUNAMI-3D models to generate sensitivity data files for each of the application cases and benchmarks. As noted previously, the application cases were selected as the bounding cases at each enrichment from the standard configuration (see Sections 6.5.1 and 6.6.1). Aside from changing the SCALE module called by the input from CSAS6 to TSUNAMI-3D, the only changes to the inputs were the cross-section library from the continuous library (ce_v7_endf) to the 238-group library (v7-238), and in the application cases the polyethylene material S(a,b) is changed to water from polyethylene. The first change is required because in SCALE6.1.3, TSUNAMI does not have the capability of using continuous energy cross sections. The change of the S(a,b) in the application cases is because TSUNAMI treats hydrogen with the polyethylene S(a,b) as a completely different isotope than hydrogen with the water S(a,b). As a result, if this change were not made, the correlation coefficients will always be very low as TSUNAMI considers the moderating materials to be completely different even though both are hydrogen based. These changes to the cross section library and S(a,b) were determined to be acceptable because TSUNAMI is only used to determine the degree of similarity between benchmarks and application cases to select which benchmarks to use in the validation. The correlation coefficients are not used for the actual validation.

The TSUNAMI-IP module uses the generated sensitivity data files to produce a correlation coefficient (the ck parameter), which measures the similarity of the systems in terms of their related uncertainty. The correlation coefficients between each benchmark and the application case for each enrichment are listed in Table 6.8.1-2. The column in this table labeled 10(5IP) is the extended 10 wt% for lower H/X values. For this column, the application case is the bounding 10 wt% U-metal case from 5-inch pipe hydrogen limited content analysis (See Section 6.6.4). The column in this table labeled 20 (HCB) is the extended 20 wt% for the higher EALF values of the HCB analysis. The criterion for being considered applicable for the validation is ck 0.9 for all enrichments 5-wt%. For the 1.25-wt% application, there were not quite enough benchmarks for the validation with this criterion, so the requirement was reduced to ck 0.85. The extended 10-wt% validation under 10(5IP) and 20-wt.% validation under 20 (HCB) use lowered requirements of ck 0.7 and ck 0.75, respectively. This is solely due to the fact that with the steel 5-inch pipes separating the two fissile masses in the application case, there is an added sensitivity to iron that is not present in a number of the benchmarks. The added benchmark series include more steel materials to help fill this gap in benchmarks, but in order to have sufficient benchmarks for the validation, the lower ck value criterion is necessary. Again, it is important to recognize at this point that the TSUNAMI selection criterion is an additional step not included in the standard validation process, as outlined in NUREG/CR-6361, to provide a more rigorous selection process for applicable benchmarks and the ck values are not used for the generation of the USL equations.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.8.1-1. Summary of Critical Benchmark Experiments Selected /

Uranium Enrichment EALF Report 1 Total Moderation Reflection H/U-235 Compound (wt.%) (eV)

Experiments HST-001 6 / 10 UO2(NO3)2 93.17 Water Bare 68.15 - 499.4 0.043 - 0.298 HST-009 4/4 UO2F2 93.17 - 93.19 Water Water 35.84 - 126.5 0.091 - 0.525 HST-010 4/4 UO2F2 93.12 Water Water 239.0 - 270.0 0.053 - 0.056 HST-011 2/2 UO2F2 93.2 Water Water 523.4 - 533.1 0.0396 - 0.0399 HST-042 8/8 UO2(NO3)2 93.2 Water Bare 1634 - 2050 0.031 - 0.032 HST-043 3/3 UO2F2 93.2 Water Bare 203.5 - 2050 0.032 - 0.074 IST-002 11 / 13 UO2F2 30.45 Water Bare, Water 76.26 - 1611 0.032 - 0.295 IST-003 21 / 21 UO2F2 30.3 Water Water 75.40 - 930.8 0.035 - 0.266 LST-001 1/1 UO2F2 5 Water Bare 453.9 0.060 LST-002 3/3 UO2F2 4.9 Water Water 1001 - 1098 0.038 - 0.040 LST-003 9/9 UO2(NO3)2 10 Water Bare 770.3 - 1438 0.034 - 0.041 LST-004 7/7 UO2(NO3)2 10 Water Water 719.0 - 1018 0.037 - 0.042 LST-007 5/5 UO2(NO3)2 10 Water Bare 709.2 - 942.2 0.039 - 0.043 LST-016 7/7 UO2(NO3)2 10 Water Water 468.7 - 771.8 0.041 - 0.052 LST-017 6/6 UO2(NO3)2 10 Water Bare 468.7 - 729.0 0.042 - 0.052 LCT-006 18 / 18 UO2 2.6 Water Water 164.7 - 329.1 0.119 - 0.260 LCT-007 10 / 10 UO2 4.738 Water Water 108.6 - 694.6 0.062 - 0.275 LCT-020 7/7 UO2 5.000 Water Water 450.9 0.063 - 0.080 LCT-023 6/6 UO2 10.00 Water Water 339.8 0.071 - 0.084 LCT-025 4/4 UO2 7.410 Water Water 72.0 - 354.8 0.071 - 0.443 LCT-031 6/6 UO2 5.000 Water Water 100.9 0.298 - 0.347 Polyethylene, LCT-033 40 / 52 UF4 2.0 Paraffin Paraffin, 195.6 - 972.8 0.050 - 0.242 Plexiglass LCT-080 11 / 11 UO2 6.903 Water Water 62.1 0.350 - 0.490 LMT-006 30 / 30 U-metal 1.600 Water Water 179.4 - 326.6 0.300 - 0.664 2

LCT-010 11 / 30 UO2 4.31 Water Steel / Water 105.5 - 256.3 0.114 - 0.320 2

LCT-019 3/3 UO2 5.26 Water Water 101.2 - 665.6 0.055 - 0.330 2

LCT-022 7/7 UO2 9.83 Water Water 50.1 - 629.5 0.055 - 0.699 LCT-024 2 2/2 UO2 9.83 Water Water 41.0 - 128.5 0.146 - 1.04 2

HCT-011 3/3 UO2 79.97 Water Water 40.8 0.431 - 0.719 2

LCT-058 9/9 UO2 4.35 Water Water 176.4 0.156 - 0.160 NOTES:

1 All reports taken from the ICSBEP Handbook [9];

2 Added benchmarks only included in the expanded 10 wt% and/or 20-wt.% HCB USLs 6-294

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.8.1-2. Summary of Critical Benchmark Experiments Enrich. EALF Combined Similarity Coefficient (ck)

Benchmark H/X (wt%235U) (eV) keff s 1.25 5 10 20 100 10 (5IP) 20 (HCB)

HST-001-01 93.17 0.08200 181.8 0.99742 0.00601 0.282 0.781 0.823 0.865 0.938 0.590 0.727 HST-001-02 93.17 0.27881 70.6 0.99276 0.00721 0.254 0.750 0.791 0.836 0.916 0.594 0.735 HST-001-03 93.17 0.08046 185.7 1.00074 0.00352 0.284 0.780 0.822 0.864 0.937 0.588 0.725 HST-001-04 93.17 0.29830 68.2 0.99707 0.00532 0.253 0.746 0.787 0.832 0.912 0.592 0.732 HST-001-05 93.17 0.04300 499.4 0.99711 0.00491 0.347 0.824 0.866 0.900 0.953 0.600 0.731 HST-001-06 93.17 0.04455 458.8 1.00155 0.00462 0.339 0.818 0.860 0.895 0.950 0.599 0.729 HST-009-01 93.19 0.52523 35.8 1.00264 0.00431 0.263 0.767 0.809 0.853 0.938 0.611 0.770 HST-009-02 93.19 0.32203 47.2 1.00272 0.00392 0.266 0.778 0.820 0.865 0.951 0.605 0.763 HST-009-03 93.19 0.15993 76.1 1.00180 0.00362 0.276 0.792 0.836 0.880 0.965 0.599 0.754 HST-009-04 93.17 0.09108 126.5 0.99756 0.00352 0.285 0.801 0.846 0.889 0.971 0.593 0.746 HST-010-01 93.12 0.05267 270.0 1.00090 0.00292 0.315 0.823 0.867 0.907 0.978 0.597 0.743 HST-010-02 93.12 0.05330 264.2 1.00176 0.00293 0.313 0.821 0.865 0.905 0.978 0.596 0.743 HST-010-03 93.12 0.05554 245.7 0.99904 0.00292 0.309 0.819 0.863 0.903 0.977 0.595 0.743 HST-010-04 93.12 0.05643 239.0 0.99771 0.00292 0.308 0.818 0.862 0.903 0.977 0.595 0.742 HST-011-01 93.2 0.03989 523.4 1.00487 0.00232 0.364 0.851 0.895 0.928 0.981 0.606 0.746 HST-011-02 93.2 0.03958 533.1 1.00088 0.00232 0.363 0.851 0.894 0.928 0.981 0.606 0.745 HST-042-01 93.2 0.03163 1634.0 1.00025 0.00391 0.620 0.884 0.910 0.893 0.823 0.574 0.663 HST-042-02 93.2 0.03174 1602.0 1.00039 0.00361 0.615 0.889 0.916 0.901 0.836 0.579 0.671 HST-042-03 93.2 0.03113 1820.0 1.00144 0.00282 0.646 0.846 0.866 0.839 0.745 0.539 0.612 HST-042-04 93.2 0.03095 1904.0 1.00252 0.00341 0.656 0.820 0.838 0.806 0.699 0.517 0.581 HST-042-05 93.2 0.03079 1978.0 0.99999 0.00341 0.662 0.796 0.811 0.775 0.659 0.495 0.553 HST-042-06 93.2 0.03087 1950.0 1.00055 0.00371 0.659 0.803 0.819 0.784 0.672 0.499 0.561 HST-042-07 93.2 0.03076 2000.0 1.00136 0.00361 0.662 0.787 0.802 0.764 0.646 0.486 0.543 HST-042-08 93.2 0.03068 2050.0 1.00187 0.00351 0.665 0.764 0.776 0.735 0.609 0.468 0.518 HST-043-01 93.2 0.07394 203.5 0.99507 0.00313 0.279 0.777 0.819 0.862 0.936 0.585 0.720 HST-043-02 93.2 0.03378 1111.0 1.00621 0.00263 0.481 0.887 0.924 0.938 0.939 0.617 0.732 HST-043-03 93.2 0.03241 1392.0 1.00242 0.00252 0.546 0.898 0.931 0.933 0.903 0.609 0.713 IST-002-01 30.45 0.04856 352.3 1.00827 0.00262 0.381 0.859 0.897 0.928 0.981 0.632 0.768 IST-002-02 30.45 0.03991 573.8 0.99972 0.00323 0.418 0.879 0.917 0.943 0.981 0.632 0.764 IST-002-03 30.45 0.03641 788.2 0.99988 0.00381 0.460 0.897 0.934 0.954 0.975 0.634 0.760 IST-002-04 30.45 0.03340 1194.0 1.00127 0.00461 0.551 0.917 0.949 0.953 0.932 0.628 0.738 IST-002-05 30.45 0.07510 217.9 1.00467 0.00422 0.341 0.813 0.846 0.880 0.938 0.634 0.757 IST-002-06 30.45 0.29482 76.3 1.00021 0.01091 0.336 0.793 0.813 0.842 0.897 0.689 0.797 IST-002-07 30.45 0.04314 533.9 1.00078 0.00322 0.392 0.846 0.883 0.911 0.951 0.625 0.748 IST-002-08 30.45 0.03492 1039.0 1.00393 0.00421 0.505 0.897 0.931 0.942 0.939 0.632 0.743 IST-002-09 30.45 0.03205 1611.0 1.00844 0.00541 0.644 0.887 0.909 0.889 0.813 0.585 0.666 IST-002-10 30.45 0.03681 765.2 1.00180 0.00381 0.455 0.893 0.931 0.951 0.975 0.634 0.760 IST-002-11 30.45 0.03351 1178.0 1.00044 0.00481 0.546 0.916 0.949 0.953 0.936 0.628 0.740 IST-003-01 30.3 0.26638 75.4 0.98876 0.01041 0.362 0.831 0.854 0.883 0.936 0.705 0.824 IST-003-02 30.3 0.15332 108.7 0.99349 0.00771 0.363 0.840 0.867 0.898 0.953 0.683 0.807 IST-003-03 30.3 0.08978 171.6 0.99832 0.00522 0.364 0.845 0.877 0.909 0.965 0.661 0.789 IST-003-04 30.3 0.06212 265.2 0.99509 0.00372 0.374 0.852 0.887 0.919 0.970 0.648 0.778 IST-003-05 30.3 0.04638 433.6 0.99689 0.00313 0.400 0.866 0.903 0.931 0.973 0.642 0.770 IST-003-06 30.3 0.03941 649.1 1.00092 0.00352 0.438 0.884 0.920 0.943 0.970 0.642 0.766 IST-003-07 30.3 0.03686 805.7 0.99964 0.00381 0.469 0.896 0.932 0.950 0.964 0.642 0.762 IST-003-08 30.3 0.03548 930.8 1.00049 0.00432 0.498 0.907 0.942 0.955 0.957 0.643 0.759 IST-003-09 30.3 0.08028 192.8 0.99853 0.00472 0.367 0.847 0.880 0.912 0.967 0.657 0.786 IST-003-10 30.3 0.03770 748.3 0.99734 0.00381 0.457 0.892 0.927 0.948 0.966 0.642 0.764 IST-003-11 30.3 0.21858 81.1 0.99724 0.00941 0.355 0.827 0.851 0.881 0.937 0.694 0.814 6-295

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.8.1-2. Summary of Critical Benchmark Experiments Enrich. EALF Combined Similarity Coefficient (ck)

Benchmark H/X (wt%235U) (eV) keff s 1.25 5 10 20 100 10 (5IP) 20 (HCB)

IST-003-12 30.3 0.21850 81.2 0.99236 0.00931 0.351 0.825 0.850 0.880 0.937 0.691 0.812 IST-003-13 30.3 0.15233 104.5 0.99239 0.00761 0.351 0.830 0.858 0.889 0.948 0.677 0.801 IST-003-14 30.3 0.11249 133.8 0.99627 0.00621 0.351 0.832 0.863 0.896 0.954 0.663 0.790 IST-003-15 30.3 0.08986 165.0 0.99590 0.00521 0.354 0.836 0.868 0.901 0.959 0.655 0.783 IST-003-16 30.3 0.06255 254.0 0.99790 0.00392 0.363 0.843 0.878 0.911 0.966 0.642 0.772 IST-003-17 30.3 0.04928 373.7 0.99908 0.00332 0.384 0.855 0.892 0.922 0.969 0.639 0.768 IST-003-18 30.3 0.04564 435.6 0.99950 0.00342 0.395 0.862 0.898 0.927 0.970 0.639 0.767 IST-003-19 30.3 0.04211 526.3 1.00114 0.00351 0.414 0.873 0.910 0.936 0.973 0.641 0.767 IST-003-20 30.3 0.03969 615.8 1.00279 0.00362 0.438 0.887 0.923 0.947 0.975 0.645 0.770 IST-003-21 30.3 0.03913 643.9 1.00308 0.00382 0.446 0.892 0.928 0.950 0.975 0.646 0.771 LST-001-01 5 0.06003 453.9 1.01162 0.00292 0.639 0.931 0.926 0.916 0.879 0.775 0.835 LST-002-01 4.9 0.03841 1098.0 0.99564 0.00401 0.724 0.940 0.947 0.923 0.857 0.666 0.741 LST-002-02 4.9 0.04029 1001.0 0.99288 0.00371 0.693 0.936 0.943 0.925 0.871 0.685 0.759 LST-002-03 4.9 0.03946 1001.0 0.99793 0.00441 0.707 0.944 0.952 0.932 0.876 0.678 0.756 LST-003-01 10 0.04098 770.3 0.99633 0.00392 0.563 0.905 0.926 0.928 0.911 0.663 0.760 LST-003-02 10 0.03917 877.6 0.99584 0.00421 0.583 0.909 0.930 0.929 0.903 0.657 0.752 LST-003-03 10 0.03889 897.0 0.99994 0.00422 0.590 0.911 0.932 0.929 0.901 0.657 0.751 LST-003-04 10 0.03866 913.2 0.99360 0.00421 0.600 0.917 0.938 0.934 0.903 0.656 0.751 LST-003-05 10 0.03596 1173.0 0.99774 0.00481 0.658 0.911 0.928 0.912 0.850 0.631 0.714 LST-003-06 10 0.03560 1213.0 0.99788 0.00491 0.667 0.908 0.924 0.906 0.839 0.626 0.707 LST-003-07 10 0.03547 1240.0 0.99716 0.00491 0.678 0.907 0.922 0.901 0.830 0.620 0.699 LST-003-08 10 0.03439 1412.0 1.00088 0.00521 0.708 0.879 0.890 0.859 0.765 0.586 0.654 LST-003-09 10 0.03429 1438.0 0.99788 0.00521 0.711 0.873 0.884 0.852 0.754 0.580 0.647 LST-004-01 10 0.04187 719.0 1.00023 0.00087 0.587 0.917 0.936 0.935 0.909 0.675 0.770 LST-004-29 10 0.04085 771.3 0.99958 0.00095 0.596 0.916 0.935 0.932 0.901 0.669 0.763 LST-004-33 10 0.03964 842.2 0.99882 0.00095 0.609 0.916 0.934 0.928 0.891 0.662 0.754 LST-004-34 10 0.03881 895.8 1.00146 0.00105 0.624 0.914 0.931 0.922 0.878 0.654 0.744 LST-004-46 10 0.03820 941.7 1.00132 0.00104 0.638 0.911 0.928 0.916 0.864 0.647 0.734 LST-004-51 10 0.03771 982.5 1.00068 0.00114 0.645 0.910 0.927 0.913 0.858 0.641 0.727 LST-004-54 10 0.03738 1018.0 1.00126 0.00114 0.659 0.908 0.923 0.906 0.843 0.633 0.717 LST-007-14 10 0.04257 709.2 0.99803 0.00095 0.558 0.898 0.918 0.920 0.904 0.662 0.759 LST-007-30 10 0.04124 770.0 0.99942 0.00097 0.575 0.901 0.921 0.920 0.897 0.658 0.753 LST-007-32 10 0.03999 842.2 0.99708 0.00105 0.592 0.904 0.923 0.919 0.888 0.653 0.745 LST-007-36 10 0.03915 896.0 0.99896 0.00114 0.611 0.907 0.925 0.918 0.880 0.647 0.739 LST-007-49 10 0.03856 942.2 0.99856 0.00114 0.625 0.908 0.927 0.917 0.873 0.641 0.732 LST-016-105 10 0.05157 468.7 1.00552 0.00133 0.565 0.926 0.942 0.946 0.934 0.709 0.808 LST-016-113 10 0.04914 514.2 1.00508 0.00134 0.572 0.929 0.946 0.949 0.933 0.706 0.804 LST-016-125 10 0.04527 608.4 1.00443 0.00144 0.591 0.934 0.952 0.952 0.929 0.698 0.796 LST-016-129 10 0.04400 650.2 1.00373 0.00144 0.600 0.937 0.954 0.953 0.925 0.696 0.792 LST-016-131 10 0.04271 699.1 1.00368 0.00144 0.613 0.940 0.957 0.954 0.920 0.692 0.788 LST-016-140 10 0.04187 738.9 1.00229 0.00154 0.625 0.942 0.959 0.953 0.913 0.690 0.784 LST-016-196 10 0.04117 771.8 1.00304 0.00153 0.636 0.945 0.962 0.954 0.909 0.690 0.782 LST-017-104 10 0.05177 468.7 1.00695 0.00135 0.544 0.914 0.932 0.938 0.934 0.697 0.798 LST-017-122 10 0.04933 510.8 1.00594 0.00134 0.550 0.917 0.936 0.941 0.935 0.693 0.795 LST-017-123 10 0.04524 610.9 1.00477 0.00144 0.575 0.926 0.945 0.947 0.931 0.687 0.788 LST-017-126 10 0.04402 650.1 1.00611 0.00143 0.585 0.930 0.949 0.950 0.930 0.685 0.786 LST-017-130 10 0.04276 699.1 1.00646 0.00153 0.601 0.935 0.954 0.952 0.926 0.683 0.782 LST-017-147 10 0.04201 729.0 1.00535 0.00153 0.614 0.938 0.957 0.953 0.921 0.681 0.780 LCT-006-01 2.600 0.24567 164.7 0.99962 0.00203 0.749 0.812 0.755 0.711 0.631 0.771 0.753 6-296

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.8.1-2. Summary of Critical Benchmark Experiments Enrich. EALF Combined Similarity Coefficient (ck)

Benchmark H/X (wt%235U) (eV) keff s 1.25 5 10 20 100 10 (5IP) 20 (HCB)

LCT-006-02 2.600 0.25345 164.7 0.99952 0.00203 0.768 0.831 0.779 0.737 0.656 0.765 0.753 LCT-006-03 2.600 0.26050 164.7 0.99951 0.00203 0.770 0.836 0.789 0.749 0.668 0.756 0.747 LCT-006-04 2.600 0.18946 201.1 0.99915 0.00203 0.738 0.831 0.777 0.737 0.664 0.775 0.767 LCT-006-05 2.600 0.19549 201.1 0.99976 0.00203 0.749 0.851 0.805 0.768 0.695 0.768 0.765 LCT-006-06 2.600 0.20121 201.1 0.99956 0.00203 0.747 0.854 0.813 0.778 0.707 0.757 0.757 LCT-006-07 2.600 0.20615 201.1 0.99975 0.00204 0.738 0.851 0.814 0.782 0.712 0.745 0.747 LCT-006-08 2.600 0.21164 201.1 0.99966 0.00203 0.725 0.841 0.807 0.777 0.710 0.731 0.734 LCT-006-09 2.600 0.14128 272.3 0.99941 0.00203 0.739 0.879 0.842 0.809 0.744 0.763 0.774 LCT-006-10 2.600 0.14495 272.3 0.99987 0.00202 0.729 0.876 0.846 0.817 0.754 0.744 0.758 LCT-006-11 2.600 0.14899 272.3 1.00015 0.00202 0.703 0.862 0.836 0.811 0.752 0.729 0.743 LCT-006-12 2.600 0.15220 272.3 0.99980 0.00203 0.692 0.849 0.826 0.802 0.744 0.712 0.725 LCT-006-13 2.600 0.15602 272.3 0.99920 0.00203 0.678 0.834 0.813 0.791 0.733 0.697 0.709 LCT-006-14 2.600 0.11932 329.1 0.99944 0.00203 0.738 0.888 0.854 0.822 0.759 0.761 0.778 LCT-006-15 2.600 0.12234 329.1 0.99984 0.00203 0.726 0.887 0.861 0.834 0.773 0.739 0.760 LCT-006-16 2.600 0.12488 329.1 0.99975 0.00202 0.707 0.871 0.850 0.824 0.765 0.716 0.736 LCT-006-17 2.600 0.12795 329.1 0.99891 0.00203 0.690 0.855 0.837 0.814 0.755 0.699 0.718 LCT-006-18 2.600 0.13060 329.1 0.99876 0.00203 0.681 0.841 0.826 0.803 0.744 0.680 0.699 LCT-007-01 4.738 0.25009 109.7 0.99695 0.00145 0.590 0.815 0.770 0.747 0.710 0.802 0.814 LCT-007-02 4.738 0.11288 229.2 0.99959 0.00089 0.575 0.889 0.871 0.863 0.849 0.784 0.834 LCT-007-03 4.738 0.07327 456.4 0.99748 0.00078 0.624 0.933 0.928 0.920 0.895 0.747 0.816 LCT-007-04 4.738 0.06242 694.6 0.99798 0.00085 0.695 0.938 0.937 0.917 0.861 0.706 0.771 LCT-007-05 4.738 0.27451 108.6 0.99624 0.00145 0.586 0.817 0.775 0.755 0.717 0.806 0.814 LCT-007-06 4.738 0.11399 229.4 0.99874 0.00093 0.566 0.886 0.868 0.862 0.850 0.782 0.832 LCT-007-07 4.738 0.07302 458.0 0.99848 0.00077 0.620 0.932 0.928 0.920 0.897 0.748 0.817 LCT-007-08 4.738 0.25880 108.6 0.99731 0.00144 0.578 0.811 0.767 0.746 0.711 0.802 0.813 LCT-007-09 4.738 0.11423 229.4 0.99827 0.00087 0.558 0.881 0.866 0.862 0.850 0.775 0.823 LCT-007-10 4.738 0.07333 458.0 0.99873 0.00076 0.610 0.922 0.920 0.913 0.889 0.739 0.805 LCT-020-01 5.000 0.08035 450.9 0.99516 0.00611 0.607 0.871 0.868 0.859 0.812 0.709 0.751 LCT-020-02 5.000 0.06966 450.9 1.00100 0.00611 0.584 0.890 0.892 0.888 0.860 0.713 0.772 LCT-020-03 5.000 0.06768 450.9 1.00291 0.00611 0.578 0.892 0.894 0.891 0.869 0.715 0.778 LCT-020-04 5.000 0.06668 450.9 1.00312 0.00611 0.580 0.897 0.898 0.895 0.875 0.720 0.785 LCT-020-05 5.000 0.06558 450.9 1.00353 0.00611 0.577 0.898 0.899 0.896 0.878 0.722 0.789 LCT-020-06 5.000 0.06489 450.9 1.00424 0.00611 0.580 0.903 0.903 0.901 0.884 0.726 0.796 LCT-020-07 5.000 0.06297 450.9 1.00459 0.00611 0.614 0.925 0.920 0.913 0.894 0.732 0.814 LCT-023-01 10.000 0.08439 339.8 0.99496 0.00441 0.496 0.832 0.841 0.850 0.797 0.735 0.758 LCT-023-02 10.000 0.07847 339.8 0.99742 0.00441 0.502 0.862 0.872 0.883 0.838 0.752 0.786 LCT-023-03 10.000 0.07621 339.8 0.99894 0.00441 0.510 0.882 0.892 0.903 0.860 0.770 0.808 LCT-023-04 10.000 0.07443 339.8 1.00124 0.00441 0.526 0.904 0.913 0.923 0.879 0.789 0.831 LCT-023-05 10.000 0.07288 339.8 1.00170 0.00441 0.531 0.917 0.924 0.935 0.892 0.805 0.851 LCT-023-06 10.000 0.07128 339.8 1.00185 0.00441 0.546 0.935 0.939 0.948 0.904 0.827 0.877 LCT-025-01 7.410 0.44317 72.0 0.98726 0.00411 0.630 0.842 0.789 0.766 0.640 0.964 0.918 LCT-025-02 7.410 0.20572 114.5 0.99518 0.00441 0.607 0.889 0.851 0.839 0.737 0.948 0.930 LCT-025-03 7.410 0.10036 216.4 0.99970 0.00471 0.595 0.926 0.905 0.903 0.821 0.907 0.920 LCT-025-04 7.410 0.07071 354.8 1.00167 0.00521 0.611 0.943 0.932 0.930 0.847 0.878 0.902 LCT-031-01 5.000 0.34732 100.9 0.99177 0.00452 0.574 0.735 0.693 0.669 0.614 0.733 0.730 LCT-031-02 5.000 0.34269 100.9 0.99608 0.00451 0.580 0.737 0.696 0.670 0.614 0.735 0.732 LCT-031-03 5.000 0.31390 100.9 0.99703 0.00451 0.567 0.738 0.696 0.672 0.622 0.738 0.737 LCT-031-04 5.000 0.31119 100.9 0.99247 0.00451 0.576 0.742 0.701 0.675 0.624 0.736 0.737 LCT-031-05 5.000 0.30896 100.9 0.99289 0.00452 0.569 0.741 0.699 0.674 0.625 0.738 0.738 6-297

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.8.1-2. Summary of Critical Benchmark Experiments Enrich. EALF Combined Similarity Coefficient (ck)

Benchmark H/X (wt%235U) (eV) keff s 1.25 5 10 20 100 10 (5IP) 20 (HCB)

LCT-031-06 5.000 0.29792 100.9 0.99351 0.00451 0.573 0.746 0.704 0.679 0.630 0.741 0.743 LCT-080-01 6.903 0.48985 62.1 0.99742 0.00106 0.513 0.767 0.725 0.708 0.680 0.802 0.812 LCT-080-02 6.903 0.48619 62.1 0.99885 0.00106 0.518 0.767 0.725 0.707 0.677 0.803 0.811 LCT-080-03 6.903 0.48308 62.1 0.99869 0.00108 0.518 0.769 0.727 0.709 0.680 0.803 0.812 LCT-080-04 6.903 0.48385 62.1 0.99803 0.00106 0.515 0.768 0.726 0.709 0.680 0.803 0.812 LCT-080-05 6.903 0.48421 62.1 0.99809 0.00105 0.514 0.767 0.725 0.707 0.679 0.802 0.811 LCT-080-06 6.903 0.48356 62.1 0.99759 0.00105 0.514 0.769 0.726 0.709 0.681 0.803 0.812 LCT-080-07 6.903 0.47684 62.1 0.99783 0.00109 0.516 0.770 0.728 0.711 0.683 0.803 0.813 LCT-080-08 6.903 0.47817 62.1 0.99810 0.00106 0.507 0.764 0.722 0.705 0.679 0.801 0.810 LCT-080-09 6.903 0.47903 62.1 0.99719 0.00106 0.518 0.771 0.730 0.712 0.683 0.803 0.813 LCT-080-10 6.903 0.48096 62.1 0.99790 0.00106 0.508 0.766 0.724 0.708 0.682 0.801 0.811 LCT-080-11 6.903 0.35039 62.1 0.99888 0.00106 0.511 0.793 0.757 0.744 0.723 0.800 0.821 LMT-006-01 1.600 0.65400 179.4 0.99678 0.00182 0.935 0.576 0.514 0.434 0.271 0.440 0.391 LMT-006-02 1.600 0.65770 179.4 0.99612 0.00182 0.932 0.568 0.506 0.425 0.260 0.435 0.384 LMT-006-03 1.600 0.66384 179.4 0.99619 0.00182 0.926 0.556 0.498 0.419 0.255 0.408 0.363 LMT-006-04 1.600 0.50129 206.2 1.00247 0.00173 0.946 0.630 0.562 0.482 0.321 0.510 0.458 LMT-006-05 1.600 0.53452 206.2 1.00066 0.00173 0.943 0.615 0.549 0.470 0.306 0.488 0.435 LMT-006-06 1.600 0.42463 234.4 1.00292 0.00163 0.946 0.656 0.587 0.508 0.350 0.539 0.487 LMT-006-07 1.600 0.42363 234.4 1.00252 0.00162 0.948 0.656 0.587 0.509 0.351 0.534 0.483 LMT-006-08 1.600 0.42645 234.4 1.00063 0.00162 0.944 0.661 0.591 0.512 0.354 0.548 0.495 LMT-006-09 1.600 0.43622 234.4 1.00098 0.00162 0.945 0.653 0.585 0.507 0.347 0.531 0.480 LMT-006-10 1.600 0.43762 234.4 1.00124 0.00162 0.943 0.658 0.590 0.511 0.352 0.543 0.490 LMT-006-11 1.600 0.45663 234.4 1.00085 0.00163 0.944 0.638 0.573 0.494 0.331 0.510 0.458 LMT-006-12 1.600 0.36744 263.9 1.00355 0.00173 0.948 0.676 0.608 0.530 0.373 0.553 0.504 LMT-006-13 1.600 0.37898 263.9 1.00203 0.00172 0.947 0.668 0.601 0.523 0.365 0.540 0.491 LMT-006-14 1.600 0.33156 294.6 1.00457 0.00192 0.954 0.679 0.614 0.535 0.377 0.536 0.492 LMT-006-15 1.600 0.33360 294.6 1.00425 0.00192 0.955 0.671 0.606 0.528 0.368 0.525 0.481 LMT-006-16 1.600 0.34049 294.6 1.00325 0.00192 0.952 0.673 0.609 0.531 0.372 0.531 0.485 LMT-006-17 1.600 0.30046 326.6 1.00491 0.00192 0.958 0.650 0.591 0.512 0.348 0.475 0.438 LMT-006-18 1.600 0.30144 326.6 1.00429 0.00193 0.957 0.648 0.590 0.511 0.348 0.473 0.437 LMT-006-19 1.600 0.60009 191.2 0.99966 0.00163 0.939 0.587 0.524 0.443 0.279 0.453 0.403 LMT-006-20 1.600 0.61970 191.2 0.99979 0.00163 0.932 0.571 0.511 0.432 0.268 0.424 0.377 LMT-006-21 1.600 0.48223 220.8 1.00071 0.00162 0.947 0.628 0.562 0.482 0.320 0.497 0.447 LMT-006-22 1.600 0.48764 220.8 1.00037 0.00163 0.947 0.629 0.562 0.482 0.321 0.500 0.450 LMT-006-23 1.600 0.49089 220.8 1.00067 0.00163 0.947 0.624 0.559 0.479 0.317 0.493 0.443 LMT-006-24 1.600 0.49627 220.8 0.99992 0.00163 0.945 0.631 0.565 0.485 0.323 0.505 0.453 LMT-006-25 1.600 0.40575 251.8 1.00340 0.00163 0.952 0.644 0.579 0.499 0.338 0.506 0.459 LMT-006-26 1.600 0.41034 251.8 1.00285 0.00162 0.952 0.645 0.581 0.501 0.340 0.504 0.458 LMT-006-27 1.600 0.41167 251.8 1.00188 0.00163 0.952 0.649 0.585 0.506 0.346 0.508 0.462 LMT-006-28 1.600 0.41595 251.8 1.00238 0.00162 0.950 0.636 0.573 0.494 0.332 0.490 0.444 LMT-006-29 1.600 0.35582 284.3 1.00358 0.00183 0.956 0.648 0.587 0.507 0.344 0.488 0.447 LMT-006-30 1.600 0.35899 284.3 1.00240 0.00182 0.955 0.648 0.587 0.508 0.346 0.491 0.449 LCT-033-01 2.000 0.20197 195.6 1.00340 0.00382 0.890 0.706 0.644 0.572 0.445 0.612 0.581 LCT-033-02 2.000 0.20200 195.6 1.00362 0.00381 0.884 0.702 0.640 0.568 0.440 0.614 0.581 LCT-033-03 2.000 0.20204 195.6 1.00426 0.00382 0.886 0.702 0.639 0.568 0.439 0.611 0.578 LCT-033-04 2.000 0.20136 195.6 1.00381 0.00382 0.887 0.701 0.639 0.567 0.438 0.610 0.577 LCT-033-05 2.000 0.11995 294.4 1.00603 0.00391 0.870 0.775 0.719 0.656 0.543 0.661 0.644 LCT-033-06 2.000 0.11992 294.4 1.00623 0.00391 0.872 0.774 0.718 0.655 0.541 0.658 0.642 LCT-033-07 2.000 0.11982 294.4 1.00622 0.00392 0.881 0.775 0.720 0.656 0.541 0.654 0.639 6-298

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.8.1-2. Summary of Critical Benchmark Experiments Enrich. EALF Combined Similarity Coefficient (ck)

Benchmark H/X (wt%235U) (eV) keff s 1.25 5 10 20 100 10 (5IP) 20 (HCB)

LCT-033-08 2.000 0.08710 406.7 1.00320 0.00401 0.869 0.818 0.770 0.711 0.605 0.673 0.670 LCT-033-09 2.000 0.08736 406.7 1.00403 0.00401 0.872 0.817 0.769 0.710 0.602 0.671 0.668 LCT-033-10 2.000 0.07404 496.2 1.00186 0.00391 0.885 0.839 0.796 0.738 0.629 0.666 0.672 LCT-033-11 2.000 0.07411 496.2 1.00155 0.00391 0.876 0.838 0.795 0.738 0.631 0.671 0.676 LCT-033-12 2.000 0.07415 496.2 1.00166 0.00391 0.877 0.839 0.796 0.739 0.632 0.670 0.676 LCT-033-13 2.000 0.06385 613.3 1.00138 0.00411 0.888 0.851 0.812 0.755 0.644 0.660 0.670 LCT-033-14 2.000 0.04957 972.8 0.99410 0.00511 0.920 0.838 0.806 0.741 0.608 0.598 0.611 LCT-033-15 2.000 0.04962 972.8 0.99439 0.00511 0.921 0.836 0.803 0.739 0.604 0.596 0.609 LCT-033-16 2.000 0.04967 972.8 0.99372 0.00511 0.919 0.840 0.808 0.744 0.612 0.599 0.613 LCT-033-23 2.000 0.24236 195.6 1.00344 0.00401 0.858 0.660 0.596 0.524 0.394 0.594 0.551 LCT-033-24 2.000 0.24210 195.6 1.00299 0.00401 0.852 0.657 0.592 0.520 0.391 0.595 0.551 LCT-033-25 2.000 0.24170 195.6 1.00329 0.00402 0.854 0.660 0.596 0.524 0.395 0.597 0.554 LCT-033-26 2.000 0.13751 294.4 1.00604 0.00391 0.869 0.747 0.689 0.623 0.504 0.645 0.620 LCT-033-27 2.000 0.13701 294.4 1.00615 0.00391 0.845 0.737 0.679 0.614 0.498 0.649 0.621 LCT-033-28 2.000 0.13710 294.4 1.00610 0.00391 0.843 0.737 0.678 0.614 0.499 0.649 0.621 LCT-033-29 2.000 0.13720 294.4 1.00619 0.00392 0.865 0.745 0.687 0.622 0.503 0.645 0.620 LCT-033-30 2.000 0.09585 406.7 1.00388 0.00392 0.884 0.801 0.751 0.689 0.574 0.658 0.650 LCT-033-31 2.000 0.09595 406.7 1.00330 0.00392 0.870 0.797 0.747 0.686 0.573 0.664 0.654 LCT-033-32 2.000 0.09607 406.7 1.00328 0.00391 0.859 0.793 0.742 0.682 0.572 0.667 0.655 LCT-033-33 2.000 0.09578 406.7 1.00202 0.00391 0.848 0.789 0.738 0.678 0.570 0.669 0.655 LCT-033-34 2.000 0.09590 406.7 1.00295 0.00391 0.848 0.790 0.739 0.679 0.571 0.669 0.656 LCT-033-35 2.000 0.07987 496.2 1.00197 0.00402 0.889 0.825 0.780 0.719 0.606 0.659 0.660 LCT-033-36 2.000 0.07973 496.2 1.00196 0.00401 0.880 0.821 0.775 0.715 0.603 0.663 0.661 LCT-033-37 2.000 0.07981 496.2 1.00155 0.00402 0.868 0.819 0.773 0.715 0.605 0.668 0.665 LCT-033-38 2.000 0.07981 496.2 1.00143 0.00402 0.864 0.815 0.768 0.709 0.599 0.668 0.663 LCT-033-39 2.000 0.07982 496.2 1.00184 0.00401 0.860 0.816 0.769 0.711 0.603 0.671 0.666 LCT-033-40 2.000 0.07985 496.2 1.00056 0.00401 0.860 0.816 0.769 0.711 0.603 0.671 0.666 LCT-033-41 2.000 0.06747 613.3 1.00120 0.00411 0.896 0.838 0.798 0.737 0.621 0.652 0.658 LCT-033-42 2.000 0.06735 613.3 1.00004 0.00411 0.878 0.837 0.795 0.737 0.625 0.663 0.665 LCT-033-43 2.000 0.06736 613.3 0.99919 0.00411 0.900 0.840 0.800 0.740 0.624 0.650 0.657 LCT-033-44 2.000 0.05063 972.8 0.99412 0.00501 0.923 0.829 0.796 0.730 0.593 0.594 0.603 LCT-033-45 2.000 0.05063 972.8 0.99418 0.00501 0.922 0.831 0.798 0.732 0.596 0.598 0.607 LCT-033-46 2.000 0.05067 972.8 0.99321 0.00501 0.922 0.833 0.799 0.734 0.599 0.598 0.608 LCT-010-09 4.310 0.12697 256.3 0.99974 0.00212 - - - - - 0.809 0.846 LCT-010-10 4.310 0.12293 256.3 1.00004 0.00213 - - - - - 0.800 0.840 LCT-010-11 4.310 0.11998 256.3 1.00045 0.00213 - - - - - 0.797 0.839 LCT-010-12 4.310 0.11653 256.3 0.99950 0.00213 - - - - - 0.788 0.832 LCT-010-13 4.310 0.11443 256.3 0.99768 0.00212 - - - - - 0.782 0.827 LCT-010-14 4.310 0.32044 105.5 1.00169 0.00282 - - - - - 0.817 0.814 LCT-010-15 4.310 0.30757 105.5 1.00186 0.00282 - - - - - 0.813 0.812 LCT-010-16 4.310 0.29716 105.5 1.00194 0.00282 - - - - - 0.810 0.811 LCT-010-17 4.310 0.29043 105.5 1.00212 0.00282 - - - - - 0.808 0.809 LCT-010-18 4.310 0.28563 105.5 1.00241 0.00282 - - - - - 0.805 0.806 LCT-010-19 4.310 0.27847 105.5 1.00187 0.00282 - - - - - 0.802 0.805 LCT-022-01 9.830 0.69873 50.1 1.00232 0.00461 - - - - - 0.955 0.932 LCT-022-02 9.830 0.29373 79.6 1.00625 0.00461 - - - - - 0.938 0.942 LCT-022-03 9.830 0.12807 150.6 1.00673 0.00362 - - - - - 0.894 0.928 LCT-022-04 9.830 0.08485 246.8 1.00669 0.00372 - - - - - 0.859 0.908 LCT-022-05 9.830 0.07026 339.8 1.00270 0.00381 - - - - - 0.842 0.895 6-299

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Table 6.8.1-2. Summary of Critical Benchmark Experiments Enrich. EALF Combined Similarity Coefficient (ck)

Benchmark H/X (wt%235U) (eV) keff s 1.25 5 10 20 100 10 (5IP) 20 (HCB)

LCT-022-06 9.830 0.05559 613.5 1.00061 0.00461 - - - - - 0.816 0.861 LCT-022-07 9.830 0.05514 629.5 1.00353 0.00461 - - - - - 0.814 0.859 LCT-024-01 9.830 1.04486 41.0 1.00012 0.00541 - - - - - 0.954 0.919 LCT-024-02 9.830 0.14580 128.5 1.00797 0.00402 - - - - - 0.909 0.935 LCT-019-01 5.000 0.32980 101.2 1.01459 0.00631 - - - - - 0.948 0.880 LCT-019-02 5.000 0.16405 158.8 1.00892 0.00582 - - - - - 0.945 0.906 LCT-019-03 5.000 0.05497 665.6 1.00614 0.00611 - - - - - 0.859 0.864 LCT-058-01 4.349 0.15860 176.4 1.00079 0.00061 - - - - - - 0.887 LCT-058-02 4.349 0.15865 176.4 1.00095 0.00060 - - - - - - 0.887 LCT-058-03 4.349 0.15885 176.4 1.00069 0.00060 - - - - - - 0.885 LCT-058-04 4.349 0.15917 176.4 1.00134 0.00060 - - - - - - 0.887 LCT-058-05 4.349 0.15947 176.4 1.00108 0.00058 - - - - - - 0.886 LCT-058-06 4.349 0.15952 176.4 1.00265 0.00058 - - - - - - 0.887 LCT-058-07 4.349 0.15558 176.4 1.00078 0.00059 - - - - - - 0.891 LCT-058-08 4.349 0.15606 176.4 1.00198 0.00062 - - - - - - 0.890 LCT-058-09 4.349 0.15646 176.4 1.00180 0.00062 - - - - - - 0.891 HCT-011-01 79.974 0.71855 40.8 0.98773 0.00421 - - - - - - 0.876 HCT-011-02 79.974 0.55184 40.8 0.98978 0.00421 - - - - - - 0.869 HCT-011-03 79.974 0.43121 40.8 0.99172 0.00421 - - - - - - 0.874 6-300

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.8.2 Bias Determination With the applicable benchmark cases for each enrichment selected, the USLSTATS code is used to generate USL equations based on a trending analysis, as described in NUREG/CR-6361. For all applications, the trending parameter with the highest correlation coefficient with keff was the moderation ratio (H/X). The results of the USLSTATS calculations are provided in Table 6.8.2-1 and Figure 6.8.2-1 through Figure 6.8.2-7. In every case the keff data tested normal and USL1 was well below USL2, verifying that the administrative margin applied (0.05) is sufficient.

Table 6.8.2-1. USL Equations and Area of Applicability by Analyzed Enrichment Enrichment Trending USL EQN AOA (wt%235U) Parameter

= 0.9380 + (4.6142E-06)*X (X < 449.05) 100 H/X 35.8 - 1392

= 0.9400 (X 449.05)

= 0.9430 + (-1.1708E-06)*X (X > 1259.8) 20 H/X 165 - 1602

= 0.9416 (X 1259.8)

= 0.9442 + (-2.0831E-06)*X (X > 1295.4) 10 H/X 216 - 1634

= 0.9415 (X 1295.4)

= 0.9480 + (-6.7842E-06)*X (X > 881.42) 5 H/X 216 - 1240

= 0.9420 (X 881.42)

= 0.9476 + (-8.9099E-06)*X (X > 545.43) 1.25 H/X 179 - 973

= 0.9427 (X 545.43)

= 0.9385 + (7.8443E-06)*X (X < 241.40) 10 (5IP) H/X 41 - 694

= 0.9404 (X 241.40)

= 0.9412 + (-6.7656E-03)*X (X > 0.19317) 20 (HCB) EALF 0.03429 - 1.0449 eV

= 0.9399 (X 0.19317)

Figure 6.8.2-1. USLSTATS Trend Plot for 100 wt%.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.8.2-2. USLSTATS Trend Plot for 20 wt%.

Figure 6.8.2-3. USLSTATS Trend Plot for 10 wt%.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.8.2-4. USLSTATS Trend Plot for 5 wt%.

Figure 6.8.2-5. USLSTATS Trend Plot for 1.25 wt%.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 Figure 6.8.2-6. USLSTATS Trend Plot for low H/X 10 wt% (5IP)

Figure 6.8.2-7. USLSTATS Trend Plot for EALF 20 wt% (HCB) 6-304

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 6.9 Appendix 6.9.1 References

[1] ANSI, "American National Standard for Nuclear Materials - Uranium Hexafluoride -

Packagings for Transport," ANSI N14.1, Latest Revision.

[2] Nuclear Regulatory Commission (NRC), Title 10, Part 71-Packaging and Transportation of Radioactive Material, 2015.

[3] International Atomic Energy Agency (IAEA), "Thorium Fuel Cycle - Potential Benefits and Challenges," IAEA TECDOC 1450, 2005.

[4] Oak Ridge National Laboratory, "SCALE: A Comprehensive Modeling and Simulation Suite for Nuclear Safety Analysis and Design," Version 6.1.3, 2013.

[5] IBILABS.com, "Uranium Trifluoride," [Online]. Available: https://ibilabs.com/uranium-uranyl-thorium-compounds/uranium-compounds/uranium-trifluoride/. [Accessed 26 Aug 2021].

[6] International Atomic Energy Agency (IAEA), "Regulations for the Safe Transport of Radioactive Material," Specific Safety Requirements No. SSR-6, 2012 Edition.

[7] J. W. McMurray, T. B. Lindemer, N. R. Brown, T. J. Reif, R. N. Morris and J. D. Hunn, "Determining the minimum required uranium carbide content for HTGR UCO fuel kernels,"

Annals of Nuclear Energy (Oxford), vol. 104, no. C, 2017.

[8] Nuclear Regulatory Commission (NRC), "Criticality Benchmark Guide for Light-Water-Reactor Fuel in Transportation and Storage Packages," NUREG/CR-6361, 1997.

[9] Organization for Economic Cooperation and Development - Nuclear Energy Agency (OECD-NEA), "International Handbook of Evaluated Criticality Safety Benchmark Experiments,"

NEA/NSC/DOC(95)03, 2019.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 CONTENTS 7 PACKAGE OPERATIONS ..................................................................................................... 7-1 7.1 Package Loading ............................................................................................................................. 7-1 7.1.1 Preparation for Loading ........................................................................................................................ 7-1 7.1.2 Loading of Contents ................................................................................................................................ 7-2 7.1.3 Preparation for Transportation ......................................................................................................... 7-3 7.2 Package Unloading ........................................................................................................................ 7-3 7.2.1 Receipt of Package from Carrier ........................................................................................................ 7-3 7.2.2 Removal of Contents ............................................................................................................................... 7-3 7.3 Preparation of Empty Package for Transport.................................................................... 7-3 7.4 Other Operations ............................................................................................................................ 7-3 7.5 References ........................................................................................................................................ 7-4 7.6 List of Appendices .......................................................................................................................... 7-4 7-i

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 7 PACKAGE OPERATIONS The Versa-Pac Shipping Package is used to transport a variety of materials, typically by non-exclusive use. It is to be loaded, inspected and handled in accordance with standard, plant operating procedures. At a minimum, the operating procedure should include the steps described in the subsequent sections.

Due to the low specific activity and low abundance of gamma emitting radionuclides, dose rates from the contents of the package are minimal. As a result of the low dose rates, there are no special handling requirements for radiation protection. As a Type AF package, the contents of the Versa-Pac are always limited to be less than or equal to an A2 quantity, calculated per the guidance of 10CFR71 Appendix A. All radioisotopes in the contents shall be included in the A2 calculation (typically uranium isotopes: U-233, U-234, and U-236).

7.1 Package Loading 7.1.1 Preparation for Loading Prior to loading the Versa-Pac, the packaging is inspected to ensure that it is in unimpaired physical condition. The inspection looks for damage, dents, corrosion, and missing hardware.

Acceptance criteria and detailed loading procedures derived from this application are specified in user written procedures. These user procedures are specific to the authorized content of the package inspected to ensure packaging complies with Appendix 1.4.1, Packaging General Arrangement Drawings.

Components requiring repair will be fixed prior to shipping in accordance with approved procedures consistent with the quality program [1].

The User shall inspect the accessible surfaces of the closure and sealing devices in accordance with approved procedures prior to loading of the container to assure the following at a minimum:

a. Ensure that the most recent certification performed is in accordance with Section 8.2.

b. The contents are within the limits of the Certificate of Compliance.

c. The package inner and outer surfaces are visually free from damage that may impair the safe use of the package.

d. The Package is free of debris or other foreign matter that could interfere with the proper and safe use of the container.

e. Verify that the outer drum and visible inner plugs are in place.

f. Gaskets are in place and intact and are not deteriorated or damaged. Replace as needed.

g. The containment flange and outer drum cover and all mating surfaces are sound and fit properly.

h. Closure bolts are the proper type and size and that thread inserts are in working order.

i. Ensure that security seal holes are functional and capable of maintaining their integrity when seals are required.

j. When utilizing the 5-inch pipe, visually inspect the threads on each pipe for damage that would interfere with the appropriate operation of the cap and body connection obtaining the minimum 5 full turns of closure. If required, repair threads by an appropriate method or replace the component.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021

k. When utilizing the High-Capacity Basket, visually inspect the outer shell of the basket and the inner surfaces of the pipe silos. If there are any cracks, fractures, or deep gouges in the pipe silos or large dents or cuts through the outer shell, the components shall be repaired by replacing the damaged part.

7.1.2 Loading of Contents All radioactive contents are loaded into the inner container. The maximum loading shall comply with the limits given in Section 1.2.2, Contents. The User shall load the packaging in accordance with in-plant approved, written procedures and at a minimum include the following items:

a. Verify that the steps previously outlined by Section 7.1.1 have been completed at a minimum.

b. If loading 1S/2S UF6 cylinder contents, verify the inner container cavity foam liner is in place at the bottom and side walls before loading the contents. The foam liner must be at least 2 inches (5.08 cm) thick at all sides, bottom and top. All 1S/2S cylinders should be cleaned of any contamination prior to loading.

c. The contents may be pre-packaged within plastic jars, sealed metal cans, plastic bags, drums or other appropriate forms; however, these items are not required for transport. Note: if using hydrogen limited content limits, verify that the total mass of hydrogenous material does not exceed the specified maximum.

d. If using the 5-inch pipe, screw the cap onto the containment vessel body until at least five but not more than eight threads are engaged.

e. If using the High-Capacity Basket, the 5-inch pipes may be pre-loaded into the basket prior to loading into the Versa-Pac or loaded into the basket in place.

f. Verify that the neoprene bottom pad is in place, if required (see Licensing Drawing NOTES for optional usage of part GC).

g. Verify that no freestanding liquids or other volatile compounds are present in the containment area prior to loading of contents.

h. Carefully load the package content into the inner container. If loading multiple 1S/2S UF6 cylinders or multiple 5-inch pipe contents, ensure each container is not in contact with one another. Cribbing or dunnage may be used to restrict movement of the contents during transport.

i. Position the neoprene sponge rubber top pad atop the contents, if required (see Licensing Drawing NOTES for optional usage of part GE).

j. If loading 1S/2S UF6 cylinder contents, verify foam liner top is in place.

k. If required, verify Containment insulation plug is in place before securing the inner container flange lid (see Licensing Drawing NOTES for optional usage of part IG). Note: when using the High-Capacity basket, use of part IG is always required. The insulation plug is placed on top of the basket arms for transport.

l. Place the inner container flange lid and gasket into place and tighten the bolts lock washers to the specified torque of 60+/-2 lb-ft.

m. Place the outer gasket and carefully install the outer reinforced insulated drum cover.

n. Install the appropriate bolts and washers and tighten to the specified torque of 60+/-2 lb-ft.

o. Secure the outer drum closure ring and tighten to 60+/-2 lb-ft and tighten the jam nut against the bolt lug.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 7.1.3 Preparation for Transportation

a. Install the security seals and record their numbers, if applicable.

b. Complete a radiation and contamination survey in compliance with the applicable regulations.

c. Remove any old labels and re-label per the applicable regulations.

d. Records should be maintained in accordance with the appropriate regulations.

7.2 Package Unloading The User shall unload the Versa-Pac in accordance with in-plant approved, written procedures and at a minimum include the following items:

7.2.1 Receipt of Package from Carrier

a. Examine the package for visible external damage.

b. Complete a receiving report and complete any surveys that are appropriate.

c. Remove and record the package seal, if applicable.

7.2.2 Removal of Contents

a. Loosen and remove the outer drum lid closure ring, reinforcing ring bolts and insulated drum cover.

b. Loosen and remove the bolts from the inner container flange.

c. Remove the contents from the inner container and verify no contents are remaining.

7.3 Preparation of Empty Package for Transport Empty Versa-Pac packages are prepared and transported per the requirements of 49 CFR 173.428 [2]. Prior to shipping as an empty Versa-Pac packaging, the packaging is surveyed to ensure that contamination levels are within the 49 CFR 173.443 limits. The packaging is inspected to ensure that it is in an unimpaired condition and is securely closed so that there will be no leakage of material under conditions normally incident to transportation.

Any labels previously applied in conformance with 49 CFR 172 Subpart E [3] are removed, obliterated, or covered and the Empty label prescribed in 49 CFR 172.450 [3] is affixed to the packaging.

7.4 Other Operations Not applicable.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 7.5 References

[1] Daher-TLI, "QUALITY ASSURANCE PROGRAM DESCRIPTION," Rev. 3, 2020.

[2] United States Department of Transportation (USDOT), "Title 49, Code of Federal Regulations, Part 173: ShippersGeneral Requirements for Shipments and Packagings, Subpart I - Class 7 (Radioactive) Materials".

[3] United States Department of Transportation (USDOT), "Title 49, Code of Federal Regulations, Part 172: Hazardous Materials Table, Special Provisions, Hazardous Materials Communications, Emergency Reponse Information, Training Requirements, and Security Plans, Subpart E - Labeling".

7.6 List of Appendices Not applicable.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 CONTENTS 8 ACCEPTANCE TESTS AND MAINTENANCE PROGRAM ........................................ 8-1 8.1 Fabrication Acceptance Tests .................................................................................................... 8-1 8.1.1 Visual Inspection and Measurements ............................................................................................. 8-1 8.1.2 Weld Examinations ................................................................................................................................. 8-1 8.1.3 Structural and Pressure Tests ............................................................................................................ 8-1 8.1.4 Leakage Tests............................................................................................................................................. 8-1 8.1.5 Component and Materials Tests ........................................................................................................ 8-2 8.1.6 Tests for Shielding Integrity ................................................................................................................ 8-2 8.1.7 Thermal Acceptance Tests ................................................................................................................... 8-2 8.1.8 Miscellaneous Tests ................................................................................................................................ 8-2 8.2 Maintenance Program .................................................................................................................. 8-3 8.2.1 Structural and Pressure Tests ............................................................................................................ 8-3 8.2.2 Leakage Tests............................................................................................................................................. 8-3 8.2.3 Component and Material Tests .......................................................................................................... 8-3 8.2.4 Thermal Tests ............................................................................................................................................ 8-4 8.2.5 Miscellaneous Tests ................................................................................................................................ 8-4 8.3 References ........................................................................................................................................ 8-5 8.4 List of Appendices .......................................................................................................................... 8-5 8-i

Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 8 ACCEPTANCE TESTS AND MAINTENANCE PROGRAM Per the requirements of 10 CFR 71.85(c) [1], this section discusses the inspections and tests to be performed prior to first use of the Versa-Pac.

8.1 Fabrication Acceptance Tests All Versa-Pac packaging materials of construction shall be examined in accordance with the requirements delineated on the drawings in Appendix 1.4.1, Licensing Drawings, per the requirements of 10 CFR 71.85(a) [1].

Source inspections and final release of the package will be performed, verifying the quality characteristics were inspected and that the packaging is acceptable. Any characteristic that is out of specification must be reported. It will then be dispositioned according to procedure. The following tests are performed by the fabricator prior to release of the packaging for use by the User.

8.1.1 Visual Inspection and Measurements Prior to the initial use, a visual inspection is performed including the following items at a minimum:

a. Confirm that the package dimensions are in compliance with the appropriate drawings (This may be accomplished by a review of the Quality Assurance and Fabrication Records).

b. Ensure that all bolts and washers are the correct type and size per the drawing.

c. Ensure that all required gaskets are in place and are in compliance with the drawings.

d. Verify that the nameplates and markings are correct.

8.1.2 Weld Examinations As part of the normal course of fabrication, the Versa-Pac is subjected to visual inspections of all welds and magnetic particle inspection of those welds shown on the fabrication drawings to ensure that the welds of the package are in compliance with the applicable codes and standards required by the drawings and specifications of the Versa-Pac. These inspections are recorded on the Fabrication Control Record as part of the Quality Assurance program [2].

8.1.3 Structural and Pressure Tests The Versa-Pac does not contain any tie-down devices that are a structural part of the package.

The Versa-Pac is handled, loaded, and unloaded using standard handling equipment. The Versa-Pac containment is rated for 15 psig. However, the silicone gasket allows gas to permeate the seal, keeping the Versa-Pac at approximately atmospheric pressure. The Versa-Pac is not a pressure-retaining package and no per unit pressure testing is required prior to use.

No other Structural or Pressure testing is performed.

8.1.4 Leakage Tests The Versa-Pac does not contain any seals or containment boundaries that require leak testing.

Therefore, this section is not applicable.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 8.1.5 Component and Materials Tests The closed cell polyurethane foam, alumina silica paper, and gasket materials are accepted in accordance with the drawing requirements and material specifications outlined in Section 1.4.

Inspect package containment components for any damage that would prove detrimental to their ability to properly function as required.

The CPVC isolation pipes and moderator plate used for the High-Capacity Basket shall be

[

]a,c 8.1.6 Tests for Shielding Integrity Shielding tests are not applicable to the Versa-Pac. The Versa-Pac does not contain any biological shielding.

8.1.7 Thermal Acceptance Tests The material properties utilized in Section 3.0, Thermal, are consistently conservative for the Normal Conditions of Transport (NCT) and Hypothetical Accident Condition (HAC) thermal analyses. As such, with the exception of the tests required for specific packaging components, as discussed in Section 8.1.5, Component and Material Tests, specific acceptance tests for material thermal properties are not required or performed.

8.1.8 Miscellaneous Tests No other additional tests are required prior to use of the Versa-Pac.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 8.2 Maintenance Program This section describes the maintenance program used to ensure continued performance of the Versa-Pac. The Versa-Pac is maintained consistent with a 10 CFR 71 Subpart H Quality Assurance program [3]. Packages that do not conform to the license drawings are removed from service until they are brought back into compliance. Repairs are performed in accordance with approved procedures and consistent with the QA program.

The User shall establish written procedures for the periodic maintenance and inspection of the Versa-Pac requiring the following as a minimum:

8.2.1 Structural and Pressure Tests The Versa-Pac does not contain any lifting/tie-down devices that require load testing. No pressure tests are necessary to ensure continued performance of the Versa-Pac.

8.2.2 Leakage Tests No leakage tests are necessary to ensure continued performance of the Versa-Pac.

8.2.3 Component and Material Tests 8.2.3.1 Prior to Each Use The following items shall be performed as a minimum prior to each package use for shipment:

a. Visually inspect the outer and inner surfaces as appropriate for rust or other superficial discontinuities. Properly trained personnel should repair any adverse indications as necessary in accordance with the drawing requirements.

b. Visually inspect all gaskets and pads for wear and/or deterioration and replace as necessary. Inner containment pads may be removed, if desired, for one-time-only shipments where the container is buried or otherwise destroyed.

c. Inspect all sealing surfaces for damage that would interfere with the safe use of the package.

d. During visual inspection, the exterior surfaces of the package should be inspected for any corrosion. If found, these areas should be evaluated in accordance with 8.2.3.2(d) below.

e. When using the VP-55 with 5-inch pipe container, visually inspect the threads on the pipe containment vessel pipe body and pipe cap. If the threads are damaged continuously from the bottom of the thread to the top, reject the part. Repair minor damage using a thread-dressing tool.

f. If shipping 1S/2S UF6 cylinders, verify that the inner cavity foam liner is not damaged.

Damage means any significant piece of the foam liner is missing such that the thickness of the liner is less than 2 inches (5.08 cm) in any location. If large pieces of foam are missing, reject the part.

g. When using the High-Capacity Basket, visually inspect the outer shell of the basket and the inner surfaces of the pipe silos. If there are any cracks, fractures, or deep gouges in the pipe silos or large dents or cuts through the outer shell, the components shall be repaired by replacing the damaged part.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 8.2.3.2 Every Five Years The Owner of the individual Versa-Pac shall perform and maintain a record of the following inspections at a minimum:

a. All inspections listed in Section 8.2.3.1.

b. Full visual inspection of all accessible surfaces and welds for the presence of cracks or other unacceptable discontinuities. Any questionable condition of a weld shall be subject to further examination to assure proper compliance. Any weld defects shall be repaired in accordance with the appropriate procedures.

c. Check flanges and covers for warping and/or distortion that prevent proper closure.

d. During the visual inspection of exterior surfaces, if areas are suspected of having corrosion, the inspection should ensure that corrosion has not reduced the outer package wall thickness by more than 10% of the nominal thickness over a 6 in.2 (38.7 cm2) square area.

When visual inspection cannot assure sufficient wall thickness, other methods of inspection should be utilized, such as ultrasonic testing, to assure acceptability.

e. All repairs shall be performed by sources that are competent and properly trained. Allowable repairs shall include repairs made to welds and base metal. Repairs that require welding shall be made by welders who are qualified in accordance with the ASME Boiler and Pressure Vessel Code [4] and/or Section 5 of AWS D1.1 [5]. Certification of weld procedures and welder qualifications shall be provided.

f. Weigh the container to verify that the container is within 10 lb. (4.54 kg) of the original fabrication weight recorded on the nameplate.

g. If the package contains payload or is in transit at the test due date, the inspection may be deferred to allow unloading and/or transport of the package, as necessary.

8.2.4 Thermal Tests No thermal tests are necessary to ensure continued performance of the Versa-Pac .

8.2.5 Miscellaneous Tests Localized deformations in the outer drum of the Versa-Pac are permitted up to 1 in. (2.54 cm) provided the shell material is not breached. The package may be repaired in accordance with the drawings in Appendix 1.4.1, Packaging General Arrangement Drawings.

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Docket No. 71-9342 Versa-Pac Safety Analysis Report Rev 13, December 2021 8.3 References

[1] Nuclear Regulatory Commission (NRC), Title 10, Part 71-Packaging and Transportation of Radioactive Material.

[2] Daher-TLI, "QUALITY ASSURANCE PROGRAM DESCRIPTION," Rev.3, 2020.

[3] Nuclear Regulatory Commission (NRC), "Title 10, Part 71-Packaging and Transportation of Radioactive Material, Subpart H - Quality Assurance".

[4] The American Society of Mechanical Engineers (ASME), "Boiler and Pressure Vessel Code, BPVC-IX -- Section IX, Welding and Brazing Qualifications," 2015.

[5] American Welding Society (AWS), "D1.1/D1.1M:2010, Structural Welding Code - Steel".

8.4 List of Appendices Not applicable.

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