ML24222A863

Attachment 4: HI-STORM 100 FSAR Proposed Revision 25, Revised Pages (Non-Proprietary)

ML24222A863
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Issue date:	08/09/2024
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To:	Office of Nuclear Material Safety and Safeguards
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1.0.1 Design Compatibility of Licensed HI-STORM 100 System Components

Each of the licensed HI-STORM 100 System components (i.e., the MPC, overpack, and transfer cask), if fabricated in accordance with any of the approved CoC Amendments, may be used with one another provided an assessment is performed by the CoC holder that demonstrates design compatibility. HI-STORM 100 Overpack and MPC combinations are listed in Table 1.0.4.

The following certified HI-TRAC transfer casks have been determined to have design compatibility and may be used with the MPCs and overpacks fabricated in accordance with the CoC #1014 amendments as listed in the table below:

HI-TRAC Design Compatibility HI-TRAC Model Program Number Serial Number Applicable CoC AmendmentsNote 1 125 1025 001 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 125 1025 002 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 125D 1025 003 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 125D 1025 004 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 125D 1025 005 2,3,4,5,6,7,8,9,10,11,12,13,14,15 125D 1025 007 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 125D 1025 008 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 125D 1025 009 2,3,4,5,6,7,8,9,10,11, 12,13,14,15 125D 1025 010 3,4,5,6,7,8,9,10,11,12,13,14,15 125D 1025 011 5,6,7,8,9,10,11,12,13,14,15 125D 1025 012 5,6,7,8,9,10,11,12,13,14,15 125D 1025 013 5,6,7,8,9,10,11,12,13,14,15 125D 1025 014 3,4,5,6,7,8,9,10,11,12,13,14,15 125D 1025 015 3,4,5,6,7,8,9,10,11,12,13,14,15 125D 1025 016 5,6,7,8,9,10,11,12,13,14,15 125D 1025 017 7,8,9,10,11,12,13,14,15 125D 1025 019 7,8,9,10,11,12,13,14,15 100 1026 001 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 100D 1026 003 2,3,4,5,6,7,8,9,10,11,12,13,14,15 100D 1026 004 2,3,4,5,6,7,8,9,10,11,12,13,14,15 100D 1026 005 2,3,4,5,6,7,8,9,10,11,12,13,14,15 100D 1026 006 2,3,4,5,6,7,8,9,10,11,12,13,14,15 100D Version IP1 1026 008 4 100D 1026 009 6,7,8,9,10,11,12,13,14,15 100G 1026 001 13,14,15 Note 1: The changes approved in Revision 1 to CoC Amendments 8 and 9 do not have any impact on the HI-TRAC designs and compatibility. Therefore, any HI-TRAC identified as compatible with Amendments 8 or 9 is by extension compatible with Amendment 8 Rev. 1 or Amendment 9 Rev. 1 respectively. Amendment 8 Rev 1 is incorporated into HI-STORM 100 FSAR Rev. 11.1.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 1-4 Table 1.0.4

ALLOWABLE HI-STORM 100 OVERPACK AND MPC COMBINATIONS

Overpack HI-TRAC MPC HI-STORM 100 HI-TRAC 100 MPC-24, MPC-24E, MPC-24EF MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100D MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100G MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC 125 MPC-24, MPC-24E, MPC-24EF MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 125D MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MS MPC-24, MPC-24E, MPC-24EF (Note 2) MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-STORM 100A HI-TRAC 100 MPC-24, MPC-24E, MPC-24EF (SA) MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100D MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100G MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC 125 MPC-24, MPC-24E, MPC-24EF MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 1-38

Table 1.0.4 (continued)

ALLOWABLE HI-STORM 100 OVERPACK AND MPC COMBINATIONS

Overpack HI-TRAC MPC HI-TRAC MPC-24, MPC-24E, MPC-24EF 125D MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MS MPC-24, MPC-24E, MPC-24EF (Note 2) MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-STORM 100S HI-TRAC 100 MPC-24, MPC-24E, MPC-24EF MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100D MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100G MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC 125 MPC-24, MPC-24E, MPC-24EF MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 125D MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MS MPC-24, MPC-24E, MPC-24EF (Note 2) MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-STORM 100S HI-TRAC 100 MPC-24, MPC-24E, MPC-24EF Version B MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100D MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 1-39

Table 1.0.4 (continued)

ALLOWABLE HI-STORM 100 OVERPACK AND MPC COMBINATIONS

Overpack HI-TRAC MPC HI-TRAC MPC-24, MPC-24E, MPC-24EF 100G MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC 125 MPC-24, MPC-24E, MPC-24EF MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 125D MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-TRAC MS MPC-24, MPC-24E, MPC-24EF (Note 2) MPC-32, MPC-32F MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS (Note 3)

HI-STORM 100S HI-TRAC 100 MPC-24, MPC-24E, MPC-24EF Version E (Note 2) MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100D MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100G MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC 125 MPC-24, MPC-24E, MPC-24EF MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 125D MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 1-40

Table 1.0.4 (continued)

ALLOWABLE HI-STORM 100 OVERPACK AND MPC COMBINATIONS

Overpack HI-TRAC MPC MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MS MPC-24, MPC-24E, MPC-24EF (Note 2) MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HI-STORM 100S HI-TRAC 100 MPC-24, MPC-24E, MPC-24EF Version E1 (Note 2) MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100D MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100G MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC 125 MPC-24, MPC-24E, MPC-24EF MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 125D MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MS MPC-24, MPC-24E, MPC-24EF (Note 2) MPC-32, MPC-32F, MPC-32M, MPC-32MCBS, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68MCBS, MPC-68 Version 1 (Note 2) (Note 3)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 1-41

Table 1.0.4 (continued)

ALLOWABLE HI-STORM 100 OVERPACK AND MPC COMBINATIONS

Overpack HI-TRAC MPC HI-STORM UVH HI-TRAC 100 MPC-24, MPC-24E, MPC-24EF (Note 4) MPC-32, MPC-32F, MPC-32M, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100D MPC-32, MPC-32F, MPC-32M, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 100G MPC-32, MPC-32F, MPC-32M, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC 125 MPC-24, MPC-24E, MPC-24EF MPC-32, MPC-32F, MPC-32M, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MPC-24, MPC-24E, MPC-24EF 125D MPC-32, MPC-32F, MPC-32M, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68 Version 1 (Note 2) (Note 3)

HI-TRAC MS MPC-24, MPC-24E, MPC-24EF (Note 2) MPC-32, MPC-32F, MPC-32M, MPC-32 Version 1 (Note 2)

MPC-68, MPC-68F, MPC-68FF, MPC-68M, MPC-68 Version 1 (Note 2) (Note 3)

HI-STORM 100U HI-TRAC 100 MPC-24, MPC-24E (Note 1) MPC-32 MPC-68 HI-TRAC MPC-24, MPC-24E 100D MPC-32 MPC-68 HI-TRAC MPC-24, MPC-24E 100G MPC-32 MPC-68 HI-TRAC 125 MPC-24, MPC-24E

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 1-42

Table 1.0.4 (continued)

ALLOWABLE HI-STORM 100 OVERPACK AND MPC COMBINATIONS

Overpack HI-TRAC MPC MPC-32 MPC-68 HI-TRAC MPC-24, MPC-24E 125D MPC-32 MPC-68 HI-TRAC MS MPC-24, MPC-24E (Note 2) MPC-32 MPC-68 Notes:

1) Information on HI-STORM 100U can be found in Supplement I.

2) Information on HI-STORM 100S Version E/E1, MPC-32M, MPC-32 Version 1, and MPC-68 Version 1 can be found in Supplement II.

3) Information on MPC-68M can be found in Supplement III.

1)4) Information on HI-STORM 100 UVH can be found in Supplement IV.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 1-43

SUPPLEMENT 1.I

GENERAL DESCRIPTION OF HI-STORM 100U SYSTEM

1.I.0 GENERAL INFORMATION

The HI-STORM 100U System is an alternative Vertical Ventilated Module (VVM) design to be used with the Holtec International Multi-purpose Canisters (MPCs) for dry storage of spent nuclear fuel at an Independent Spent Fuel Storage Installation (ISFSI). Information pertaining to the HI-STORM 100U System is generally contained in the I supplements to each chapter of this FSAR. Certain sections of the main FSAR are also affected and are appropriately modified for continuity with the I supplements.

Unless superseded or specifically modified by information in the I supplements, the information in the main FSAR is applicable to the HI-STORM 100U System. Drawings specific to the HI-STORM 100U VVM are in Subsection 1.I.5. The Glossary has been appropriately augmented to include the terms particular to the HI-STORM 100U VVM.

1.I.1 INTRODUCTION

HI-STORM 100U, like HI-STORM 1003 and HI-STORM 100S4, is a vertical, ventilated dry spent fuel storage system engineered to be fully compatible with the presently certified HI-TRAC transfer casks and MPCs. HI-STORM 100U is an underground vertical ventilated module (VVM) designed to accept all MPC models for storage at an ISFSI (see Figure 1.I.1). MPC types that can be stored in the below ground VVMs are identified in Table 1.0.4. ISFSIs employing the VVM may be designed for any number of MPCs and expanded to add additional storage modules as the need arises. Each VVM stores one MPC.

The design and operational attributes of the HI-STORM 100U VVM, described in the following paragraphs pursuant to the provisions of 10CFR72.24(b), are subject to intellectual property rights in the U.S. and abroad under the patent laws governing the respective jurisdictions.

1.I.2 GENERAL DESCRIPTION OF HI-STORM 100U SYSTEM

1.I.2.1 HI-STORM 100U Vertical Ventilated Module

The VVM provides for storage of MPCs in a vertical configuration inside a subterranean cylindrical cavity entirely below the top-of-the-grade (TOG) of the ISFSI (Figure 1.I.2 provides identification of the TOG). The MPC Storage Cavity is defined by the Cavity Enclosure Container (CEC), consisting of the Container Shell integrally welded to the Bottom Plate. The top of the Container Shell is stiffened by the Container Flange (a ring shaped flange), which is also integrally welded. As shown in licensing basis drawings provided in Section 1.I.5, all of the constituent parts of the CEC are made of thick low carbon steel plate (See Table 2.I.8 for component materials). In its installed configuration, the CEC is interfaced with the surrounding subgrade for most of its height except for the top region where it is girdled by the ISFSI pad. The ISFSI pad serves several purposes in the HI-STORM 100U storage system, such as:

3 U.S. Patent No. 6,064,710 dated May 16, 2000.

4 U.S. Patent No. 6,718,000 dated April 6, 2004.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 1.I-1

Level A service condition in Subsection NF of the ASME Code are applied to establish the embedded structural margins of safety in the primary load bearing parts of the VVM under normal conditions of storage. For short term and accident conditions (i.e., earthquakes, missile strike, etc.), the continued functional adequacy of the system is the appropriate criterion. For the VVM, continued functional adequacy under accident or extreme environmental events demands absence of a complete blockage of the ventilation passages and a non-significant amount of loss of shielding. Supplement 2.I provides complete details on the applicable design criteria.

All MPC types certified for storage in the aboveground overpacksMPC types that can be stored in the below ground VVM are identified in Table 1.0.4. The chief distinguishing features of the VVM are its low profile and subterranean configuration. The Container Shell is buried below the ISFSI Pad for virtually its entire height, resulting in a near complete blockage of laterally emanating radiation from the stored fuel.

In summary, the notable design and operational features of the HI-STORM 100U System are:

i. The MPC is supported on MPC Bearing Pads to provide an inlet air plenum at the bottom of the storage cavity (Figure 1.I.2). The bottom of the MPC, however, will be in contact with water if the cutouts at the bottom of the Divider Shell were to be filled with water cutting off feed air. As long as the MPC is wetted with water, the peak cladding temperature of the stored spent fuel will not exceed the regulatory off-normal condition temperature limit. Thus, the VVM configuration provides a built-in protection against flood events.

ii. Like the HI-STORM 100A and 100SA models, tipover of the canister in storage is not possible.

iii. Although the modules may be closely spaced, as illustrated in Figure 1.I.5, the design permits any MPC located in any cavity to be independently accessed and retrieved using a HI-TRAC transfer cask.

iv. A cask transporter typical of those used in numerous Holtec ISFSI projects for on-site transport of loaded HI-TRACs and HI-STORMs can provide the means to deliver the loaded HI-TRAC to the HI-STORM 100U VVM and to carry out the MPC lowering operation (Figure 1.I.7). The same cask transporter can also be used to remove an MPC from storage and place it in a recipient HI-TRAC transfer cask.

v. To exploit the biological shielding provided by the surrounding soil subgrade, the MPC is entirely situated well below the top-of-grade level. The open plenum above the MPC also acts to boost the ventilation action of the coolant air.

vi. Because the VVM is rendered into an integral part of the subgrade, it cannot be translocated to another ISFSI site. It also cannot be lifted and, therefore, is not subject to the potential for a handling accident.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 1.I-6

defined pathway for the incoming ventilation air. Each oblique tube is in a radial plane substantially separated from each other to minimize local increase in the accreted radiation from the cask typical of inlet ducts.

An important benefit of the inlet vent system employed in Version E is the ability it imputes to the canister to continue to reject its decay heat in the event of a flood event that blocks the flow of incoming air.

Because blocking of the elevated inlet vent with flood water will partially wet the MPC, which has recirculating helium from internal thermo-siphon effects, an effective means for heat rejection to the surrounding flood water is established without any operator action.

c. Directing the inlet air flow towards the bottom of the MPC serves to slightly pre-heat the incoming air, alleviating the stress-corrosion risk to the lower portion of the MPC shell (where it is most vulnerable).

d. As a key design objective, while the air flow areas are enlarged to facilitate increased ventilation flow, the design ensures that the flow regime throughout the VVM will continue to be fully turbulent at the systems Design Basis Heat Load (DBHT).

e. The MPC sits on a thin stainless liner (MPC support guides replaced with stainless steel tiles for the Version E1) welded to the Bottom Plate so that it is not in direct contact with the carbon steel bottom plate of the overpack

f. The density of the shielding concrete (Appendix 1.D) in the overpack body and Top Lid has been increased to enhance dose attenuation (See Table 1.II.2.4.) [1.II.2]

g. The massive Top Lid, which is held in place by four large anchor bolts has been designed such that during the non-mechanistic tip-over event, the lid will impact the ISFSI pad independently of the cask body because of the large clearances around each bolt hole. This feature has the beneficial effect of ameliorating internal stresses in the cask from the tip-over event.

Table 1.II.2.5 provides the essential design data required for the safety analysis of Version E overpack cask in the subsequent chapters. Table 1.II.2.1 lists the sections from the main body of the FSAR used to evaluate the improved features of Version E as analyzed in the supplement II to each chapter.

1.II.2.2 Multi-Purpose Canister (MPC)

The MPC for all HI-STORM/HI-STAR systems consists of two principal components, namely (i) The Enclosure Vessel (EV) which is an all-welded pressure vessel of the highest ASME Code pedigree, and (ii) The Fuel Basket.

MPC-32M, MPC-32MCBS, MPC-32 Version 1 and MPC-68 Version 1 utilize Enclosure Vessel Version 1 listed in section 1.II.5. For reference purposes, a listing of MPCs allowed for storage in the Version E and Version E1 is provided in Table 1.0.4II.2.2. MPC-32M, including the MPC-32MCBS variant, along with version 1 of MPC-32 and MPC-68 are the subject of the safety analysis in this Supplement II.

(i) MPC-32M (including MPC-32MCBS): Certain design attributes of MPC-32M are summarized below, most of which it shares with all other MPC models:

a. Like all MPCs, MPC-32M and its MPC-32MCBS variant will be handled by a set of Lift Cleats (under Special lifting devices in the regulatory literature) that engages with threaded anchor locations (TALs) in the top lid. The lifting appurtenances of the Enclosure Vessel body must meet the stress margin criteria of NUREG-0612 and ANSI 3.61.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 1.II-5

Table 1.II.2.2 MPC Models Allowable for Storage in the HI-STORM 100 Version E (including the Version E1)Deleted (Information moved to Table 1.0.4)

MPC Model Applicable SNF Number of Fuel Baskets Structural material Number Type Storage Cells

MPC-68 and BWR 68 Alloy X (stainless steel)

MPC-68 Version 1

MPC-68M and BWR 68 Metamic HT MPC-68MCBS MPC-24 PWR 24 Alloy X

MPC-24E PWR 24 Alloy X

MPC-32 & MPC- PWR 32 Alloy X 32 Version 1 MPC-32M and PWR 32 Metamic HT MPC-32MCBS

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 1.II-10

1.IV.2 General Description

1.IV.2.1 System Characteristics

The components of the UVH Storage system are listed in Table 1.IV.1.1. The description of the UVH Overpack is provided in this section. The HI-TRACs and MPCs are described in Chapter 1 and other adopted supplements to this FSAR, and these descriptions remain applicable to this supplement. The overpack, illustrated in the licensing drawing in Section 1.IV.5, is sized to store the designated reference MPCs described below.

1.IV.2.1.1 MPCs:

No new MPC designs are proposed in this supplement and there are no modifications to existing designs for this supplement. MPC types that can be stored in the HI-STORM 100 Version UVH are identified in Table 1.0.4. The MPC models qualified for the HI STORM 100 Version UVH System were previously certified or are subject to certification in Supplements 1.II and 1.III of this FSAR.

1.IV.2.1.2.1 Version UVH Overpack:

This supplement adds the HI-STORM 100 Version UVH (Version UVH) overpack to the HI-STORM 100 Canister storage system. Like all other overpack models previously evaluated in this FSAR, Version UVH is a dual buttressed steel shell structure with the inter-shell space filled with plain concrete. Because of its steel external body, Version UVH can be arrayed in a freestanding configuration. Likewise, the storage system can be deployed in a sheltered (inside a ventilated building) or unsheltered state.

The key distinguishing feature of Version UVH is that it has no inlet or outlet vents. Thus, there is no ventilation flow of air around the MPC. Rather the cask is designed to reject the fuels decay heat from the external surface of the Canister without the benefit of ventilation flow. Rejection of heat from the external surface of the Canister to the external surface of the overpack is facilitated by a combination of conduction and radiation modes of heat transmission. The diametrical clearance between the overpack and the MPC is minimal which, under the design basis heat load, is further reduced allowing for conduction based heat transfer to assist in heat dissipation. Radiation from the hot MPC surfaces to the casks inner surfaces also plays an active heat dissipation role. Additionally, radial ribs in the overpack body and lid assist in heat dissipation to cask external surfaces. Finally, the shielding concrete used in Version UVH is of high density rich in hematite class of aggregate which ensures a high thermal conductance across its mass. Heat rejection from the overpack to the ambient environment like all other HI-STORM overpack models, occurs through natural convection from the casks exposed surfaces.

The Closure Lid for Version UVH is also a steel structural weldment with high density, high conductivity concrete installed inside its structure to provide protection against sky shine. The Closure Lid is installed on the cask body by a set of equidistant anchor bolts with a small clearance and an interposed flat concentric gasket limiting exposure of the overpack internal cavity to the external environment and, thus, reducing the probability of stress corrosion cracking (SCC) in the HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2114830 Proposed Revision 255 1.IV-8

SUPPLEMENT 2.II: PRINCIPAL DESIGN CRITERIA 2.II.0 Scope and Introduction

The principal design criteria for the HI-STORM 100 storage system are derived from 10CFR72 [2.II.1]. This supplement applies to Chapter 2 of the HI-STORM 100 FSAR appropriately updated using latest NRC-approved FSAR (HI-STORM FW) [2.II.2]. This supplement supports the HI-STORM 100 system containing the HI-STORM Version E overpack (including the HI-STORM Version E1 overpack), HI-TRAC Version MS transfer cask, MPC-32M multi-purpose canister, including the MPC-32MCBS variant, and Version 1 of MPC-32 and MPC-68 (Alloy X canisters). The design criteria for HI-TRAC MS transfer cask allow the alternative of using a ventilation feature that provides a significantly better heat dissipation ability and ALARA characteristics compared to HI-TRAC 100 and HI-TRAC 125 casks that are presently certified for this purpose.

A principal objective of this revision to the FSAR is to update the licensing-basis analysis models which are in some cases, over two decades old and essentially obsolete in comparison to more recent FSARs such as HI- STORM FW ( Docket # 72-1032) . This issue of the FSAR will therefore serve as reference of the authoritative state-of-art safety analysis models which will help harmonize the analysis procedures for HI-STORM 100 and FW systems unifying the approach for future site- specific safety evaluations and §72.48 changes. This licensing submittal contains all actively used MPC models.

2.II.0.1 Summary of MPC Design Criteria The design data common to the MPC models introduced in this supplement is provided in Table 1.II.2.3. The Design Criteria for the MPCs provided in Table 2.0.1 in the main body of this FSAR remain applicable for the MPCs introduced in this Supplement II with the following clarifications:

a. Forced Helium Dehydration (FHD) and Vacuum drying are two distinct methods available for drying the Canister. The FHD may be used without limitation for drying the confinement space of the Canister containing both high burn- up and moderate burn- up fuel.

The Vacuum drying method may be used provided the restrictions on fuel cladding temperature limits and number of thermal cycles set forth in ISG-11 Rev 3 are met for the applicable burn-up class of the fuel (moderate or high burn-up).

b. For Fuel Baskets made of Metamic HT, the structural acceptance criteria rely on both stress and deflection limits to ensure structural integrity and criticality safety. The maximum primary membrane plus bending stress in the fuel basket panels, within the active fuel region, must be below 90% of the ultimate strength of Metamic-HT material, on a true stress basis, at the applicable temperature. In addition, the permanent lateral deflection of the basket panels shall satisfy the limit based structural criterion applies as set forth in Subsection 2.II.2.4Supplement III (wherein MPC-68M, presently certified and widely deployed, made of Metamic HT has been qualified) as well as in the HI-STORM FW FSAR [1.II.1]. Fuel Baskets made of Alloy X listed in the ASME Codes (various types of stainless steels listed in Appendix 1.A) namely Version 1 of MPC-32 and MPC-68, continue to be subject to the same stress limits as their forerunners treated in the main body of this FSAR.

c. The MPC confinement boundary is qualified to ASME Section III Class 1 requirements with respect to all critical aspects including procurement, examination, testing, stress intensity HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.II-1 compliance, quality assurance, and satisfaction of all service condition loads. For example, all MPC Enclosure Vessel material is subject to 100% volumetric examination (viz., UT); all butt- welds in the fabricated Enclosure Vessel weldment are also subject to 100% radiography or UT examination.

d. The MPC shall meet the acceptance criteria per Table 2.II.2.3b under all Design Basis Loads (DBLs) under all applicable service conditions.

e. The Threaded Anchor Locations (TAL) in the Top Lid shall meet the safety margins set down in NUREG-0612 with 15% dynamic amplifier factor applied to the dead load.

f. Per Table 2.II.2.6, pressure testing (hydrostatic or pneumatic) is not required for the MPC-32M (including the MPC-32M CBS design variant), MPC-32 Version 1, or MPC-68 Version 1.

The above criteria and applicable loads for the MPCs are further considered in Section 2.II.2 in this supplement.

2.II.0.2 Summary of Design Criteria for HI-STORM Version E Overpack (including the HI-STORM Version E1)

The Design Criteria for the HI-STORM overpack listed in Table 2.0.2 (in the main body of this FSAR) remain applicable with the following clarifications:

a. While the HI-STORM Overpacks steel structure is non-Code, the primary bending and in-plane stresses in the steel components shall meet the stress limits of ASME Section III Subsection NF Class 3 structures under all applicable normal loading events except for the impact loading. For impact loading the following criteria shall be met.

b. The Overpacks principal function, namely protecting its stored MPC and prevention of radiation streaming under impactive and impulsive loadings during its interim storage at the ISFSI must be demonstrated.

c. The Threaded Anchor Locations (TAL) in the Top Lid shall meet the safety margins set down in NUREG-0612 with 15% dynamic amplifier factor applied to the dead load.

The above criteria and applicable loads for Version E are further considered in Section 2.II.2 in this supplement.

2.II.0.3 Summary of HI-TRAC MS Design Criteria

The HI-TRAC MS is a ventilated overpack with a multi-buttressed steel shell structure. The HI-TRAC MS design includes a detachable Neutron Shield Cylinder (NSC) feature that can be removed for movements of the MPC and HI-TRAC into and out of the pool such that the amount of gamma shielding is maximized relative to the crane capacity while the water in the MPC provides neutron shielding. The HI-TRAC is then placed inside of and connected to the NSC such that it provides neutron shielding after the water is drained from the MPC. To meet the diverse needs of different users (nuclear plants), the HI-TRAC MS is available with or without lifting trunnions as shown in the licensing drawing. The shielding in the HI-TRAC MS is maximized within the constraint of the allowable weight at a plant site. Its Design Criteria

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.II-2 Table 2.II.0.1

Reference ISFSI Pad Data for Non-Mechanistic Tip-Over Analysis

Item Minimum Permitted Value

Thickness (inch) 3036

Concrete Pad Compressive Strength (psi) 5,0006,000

Modulus of elasticity of the subgrade (psi) 28,000

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.II-6 Table 2.II.1.1 Limits for Material to be Stored in MPC-32M

PARAMETER VALUE (Note 1)

Fuel Type Uranium oxide, PWR undamaged Uranium oxide, PWR damaged fuel assemblies meeting the limits fuel assemblies and fuel debris in in Table 2.II.1.8 for the applicable DFCs meeting the limits in Table fuel assembly array/class 2.II.1.8 for the applicable fuel assembly array/class Cladding Type ZR for all fuel assembly array/ ZR for all fuel assembly array/

class except Stainless Steel (SS) class except Stainless Steel (SS) for 14x14D and 15x15G fuel for 14x14D and 15x15G fuel assembly array/class. assembly array/class.

Maximum Initial Enrichment per 5.0 wt. % U-235 5.0 wt. % U-235 Assembly

Post-irradiation Cooling Time and ZR clad: Cooling time year Zr clad: Cooling time year Average Burnup per Assembly and average burnup < 68,200 and average burnup < 68,200 MWD/MTU MWD/MTU

SS clad: Cooling time > 9 years SS clad: Cooling time > 9 years and < 30,000 MWD/MTU or > 20 and < 30,000 MWD/MTU or >

years and < 40,000MWD/MTU 20 years and <

40,000MWD/MTU

Decay Heat Per Fuel Storage ZR clad: As specified in Section ZR clad: As specified in Section Location 2.II.1.5. 2.II.1.5.

SS clad: < 500 Watts SS clad: < 500 Watts

Non-fuel hardware post-irradiation Cooling Time and Burnup As specified in Table 2.II.1.2 As specified in Table 2.II.1.2

Fuel Assembly Length < 176.8 in. (nominal design) < 176.8 in. (nominal design)

Fuel Assembly Width < 8.54 in. (nominal design) < 8.54 in. (nominal design)

Fuel Assembly Weight 1,5202,050 lbs (including non- 1,5202,050 lbs (including fuel hardware) DFC/DFI and non-fuel hardware)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.II-10 Specific limits on the HI-TRACs accreted dose is not in the regulatory literature; however, hard limits in the spirit of ALARA are specified herein.

d. Criticality Compliance: Supplement 6.II contains the results of the criticality analyses and demonstrates compliance with the sub-criticality margin specified in Section 2.2 of the FSAR for the MPCs introduced in this Supplement II.

2.II.2.2 Detailed Acceptance Criteria for Mechanical Loadings

Articulated acceptance criteria for each mechanical loading listed in Table 2.II.2.1 are provided below.

a. High Wind and Design Basis Missile (DBM) [Load ID M-1]: The wind and tornadic missile loadings apply to both HI-STORM in storage and the HI-TRAC transfer cask during part 72 short term operations. The applicable acceptance criteria are itemized below:

1) The deformation of the cask body from the missiles impact must be sufficiently small to preserve the Canisters retrievability.

2) The bolted lid of the cask will not separate from the body resulting in excessive personnel dose.

3) The loss of bulk shielding, if any, shall not be significant.

4) The missile shall not impact the cylindrical surface of the stored MPC.

5) A dose streaming path will not be created by the missile impact.

b. Non-Mechanistic Tip-Over [Load ID: M-4]

1) The MPC will remain in the HI-STORM overpack after the tip-over event and the overpack will not suffer any ovalization which would preclude the removal of the MPC.

2) The maximum primary membrane plus bending stress in the fuel basket panels, within the active fuel region, is limited to 90% of the true ultimate strength of Metamic-HT material at the applicable temperature.

2)3) The maximum plastic deformationpermanent deflection for the Metamic baskets (MPC- 32M and MPC-32MCBSbasket) sustained by the fuel basket panels is limited to the value given in Table 2.II.2.4.

3)4) The HI-STORM overpack will not suffer a significant loss of shielding.

4)5) The confinement boundary will not be breached.

It shall be noted that the handling drops (Load Cases M2 and M3) for the HI-STORM and HI-TRAC casks are precluded by virtue of meeting the redundant load path requirements from NUREG-0612.

In case the handling drops are credible due to the use of non-redundant lifting devices for a specific site, the above acceptance criteria shall be applied for the postulated drops of the HI-STORM and the HI-TRAC. The site-specific conditions will be evaluated as part of the 10CFR72.212 process.

c. Design Basis Earthquake HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.II-31

a. Normal Condition of Storage (T-1): The reference ambient conditions corresponding to the normal, off-normal and accident conditions of storage are provided in Table 1.II.2.3. These environmental conditions have been determined to bound their respective meteorological data for the entire continental United States.

Unsheltered condition of storage requires inclusion of insolation to the storage system as external heat input.

The fuel cladding temperature limits pursuant to ISG 11 Rev 3 are provided in Table 1.II.2.3. The temperature limits on other ITS parts of the HI-STORM 100 system are provided in Table 2.2.3.

b. Accident Condition of Storage: This condition is characterized by an elevated ambient temperature (Table 1.II.2.4) and 100% rod rupture.

For conservatism, 100% of the fuel rods are assumed to rupture with 100% of the fill gas and 30% of the significant radioactive gases (e.g., H3, Kr, and Xe) released in accordance with NUREG-1536. All of the fill gas contained in non-fuel hardware, such as burnable poison rod assemblies (BPRAs), is also assumed to be released concomitantly. Because of the relatively high fuel cladding temperature limit for this condition (Table 1.II.2.3 and Table 2.2.3), the accident condition of storage has not been found to challenge the temperature limits in HI-STORM systems.

b. Design Basis Fire:

The accident condition design temperatures for the HI-STORM 100 System are specified in Table 2.2.3. The specified fuel cladding temperature limits are based on the temperature limits specified in ISG-11, Rev. 3 reproduced in Table 1.II.2.3.

2.II.2.4 Applicability of Governing Documents

Section III Subsection NB of the ASME Boiler and Pressure Vessel Code (ASME Code), [2.II.8], is the governing code for the structural design of the MPC. The alternatives to the ASME Code, Section III Subsection NB, applicable to the MPC are listed in Table 2.II.2.6. Table 2.II.2.8 provides the ASME Code, Section and Subsection for manufacturing requirements.

The stress limits of ASME Section III Subsection NF [2.II.9] are applied to the HI-STORM overpack and HI-TRAC MS structural parts where the applicable loading is designated as a code service condition.

The MPC-32M and MPC-32MCBS fuel baskets, made of Metamic-HT, areis subject to the stress and deflection requirements specified in this supplementin Supplement II to this FSAR. From a stress standpoint, the primary membrane plus bending stresses in the fuel basket panels, within the active fuel region, are restricted to 90% of the ultimate strength of Metamic-HT material, on a true stress basis, at the applicable temperature.

StructuralThe deflection limits on the Metamic HT panel, which is used as input to the criticality safety analysis in Supplement 6.II, is specified as a (lateral) permanent deformation limit of its walls under accident conditions of loading (credible and non-mechanistic) (see Table 2. II. 2.4). The basis for the permanent lateral deflection limit, , in the active fuel region, , is provided in [2.II.11] and supplemented by the discussion in Subsection 6.II.3.1]. The portions of the fuel basket outside of the active fuel region are not subject to the deflection limit since they do not affect the reactivity control function of the Metamic-HT fuel basket. The height and relative position of the active fuel region with respect to the fuel basket are dependent on the fuel assemblies being stored in the MPC, as the MPC height can be varied to accommodate different fuel types (see Table 3.II.2.1).

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.II-34 The Version1 Alloy X fuel baskets are subject to the requirements of Section III, Subsection NG of the ASME Code, identical to their predecessor designs viz. MPC 32 and MPC 68 baskets. The acceptance criteria for these baskets is summarized in Table 2.II.2.3a.

ACI 318 [2.II.7] is the reference code for the plain concrete in the HI-STORM Overpack. ACI 318.1-85(05) is the applicable code utilized to determine the allowable compressive strength of the plain concrete credited in strength analysis.

Each structure, system and component (SSC) of the storage system that is identified as important-to-safety is shown on the licensing drawings in Section 1.II.5.

Table 2.2.15 provides the information on the applicable Codes and Standards for material procurement, design, fabrication and inspection of the components of the HI-STORM 100 System. In particular, the ASME Code is relied on to define allowable stresses for structural analyses of primary load bearing parts.

To maintain continuity, the allowable stress tables from the originally referenced Section III of the ASME Code (1995 with all addenda including 1997) continue to be used in this Supplement. However, material specifications, NDE specifications, welding specifications are updated to the 2016 edition of the Code to conform to the industry practice (viz., materials to non-current codes are scarce to procure).

2.II.2.5 Service Limits

In the ASME Code, plant and system operating conditions are commonly referred to as normal, upset, emergency, and faulted. Consistent with the terminology in NRC documents, this FSAR utilizes the terms normal, off-normal, and accident conditions.

The ASME Code defines four service conditions in addition to the Design Limits for nuclear components.

They are referred to as Level A, Level B, Level C, and Level D service limits, respectively. Their definitions are provided in Paragraph NCA-2142.4 of the ASME Code. The four levels are used in this FSAR as follows:

i. Level A Service Limits are used to establish allowables for normal condition load combinations.

ii. Level B Service Limits are used to establish allowables for off-normal conditions.

iii. Level C Service Limits are not used.

iv. Level D Service Limits are used to establish allowables for certain accident conditions.

The ASME Code service limits are used in the structural analyses for definition of allowable stresses and allowable stress intensities, as applicable. Allowable stresses and stress intensities for structural analyses are tabulated in Chapter 3. These service limits are matched with normal, off-normal, and accident condition loads combinations in the following subsections.

2.II.2.6 Allowable Stress/Deflection Limits

(i) MPC Confinement Boundary: The stress intensity limits for the MPC confinement boundary for the design condition and the service conditions are provided in Table 2.II.2.3b. The MPC confinement boundary stress intensity limits are obtained from ASME Code,Section III, Subsection NB.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.II-35 (ii) Metamic HT Baskets (MPC-32M and, including MPC-32MCBS): The maximum primary membrane plus bending stress in the fuel basket panels, within the active fuel region, must be below 90% of the ultimate strength of Metamic-HT material, on a true stress basis, at the applicable temperature. This primary stress limit, which is adopted from subparagraph F-1341.2 of the ASME Code [2.II.9], is the key determinant of the baskets structural integrity under accident conditions. Notwithstanding the stress criterion, an additional deflection limit is imposed on the Metamic-HT fuel baskets to ensure their structural integrity and criticality safety. As in the case of MPC-68M analyzed in Supplement III and certified previously, the deflectiondisplacement limit for the MPC fuel basket is expressed as a dimensionless parameter defined as [2.II2.11]:

where is defined as the maximum average permanenttotal deflection sustained by the basket panels under the loading event and w is the nominal inside (width) dimension of the storage cell. Stated differently, is the maximum permanent deflection of a Metamic-HT panel averaged over the panel width, which is converted to a dimensionless parameter by dividing the average deflection by the unsupported panel width. The limiting value of is provided in Table 2.II.2.4, and it is also used conservatively to inform the criticality analysis model for the Metamic-HT fuel baskets, as described in Subsection 6.II.3.1.

(iii) Alloy X Baskets (Version 1 of MPC-32 and MPC-68): The stress limits defined in Table 2.II.2.3a, are the same as those applicable to the predecessors of these baskets. The numerical values of stress limits are presented in Tables 3.1.15 and 3.1.16.

(iv) Overpacks: The steel structure of the HI-STORM Version E overpack, HI-STORM Version E1 overpack and the HI-TRAC MS transfer cask must meet the stress limits of Subsection NF of ASME Code,Section III for the applicable service conditions except for the impact loadings. The impact loading shall use the acceptance criteria from section 2.II.2.2b.

Table 2.II.2.5 provides the location of mechanical properties for the MPC, and the storage and transfer overpacks for convenience of reference.

The following definitions of terms apply to the tables on stress intensity limits; these definitions are the same as those used throughout the ASME Code:

Sm: Value of Design Stress Intensity listed in ASME Code Section II, Part D, Tables 2A, 2B and 4

Sy: Minimum yield strength at temperature

Su: Minimum ultimate strength at temperature

2.II.2.7 Lifting and Handling Safety

All lifting devices whether custom engineered or commercially procured are subject to stringent structural margin requirements as spelled out in the following in this sub-section. All new lifting and handling equipment shall meet the enhanced safety margin criteria which render them exempt from a postulated drop consequence analysis. Such devices are referred to as drop-postulate exempt (DPE) which is synonymous with the term Single Failure Proof used in NUREG-0612 and Regulatory Guide 1.13. Single Failure Proof HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.II-36 Table 2.II.2.2

Governing Thermal Loading Conditions

Thermal Caption of Loading FSAR Applicable to Comments Loading paragraph HI-STORM ID where the /HI-TRAC?

loading is discussed T- 1 Normal Condition of 2.2.1 HI-STORM The ISG-Rev 3 peak cladding Storage temperature limits reproduced in T-2 Design Basis Fire 2.2.3.3 Both Table 1.II.2.23 must be met. In addition, the temperature of T-3 Two inlet ducts blocked 2.2.3.4 HI-STORM proximate safety significant materials must meet the T-4 Burial- under- debris 2.2.3.12 HI-STORM temperature limit in Table 2.2.3 T-5 All inlet ducts blocked 2.2.3.13 HI-STORM in the main body of the FSAR

T-6 Short Term Operations 2.2 HI-TRAC

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.II-41 Table 2.II.2.4

Structural Design Criteria for the Fuel Basket

PARAMETER VALUE

Minimum service temperature -40ºF

Maximum average permanenttotal (lateral) deflection in the active fuel region, - (dimensionless) 0.005

Refer to Subsection 2.II.2.6 for more information on deflection limit. Not applicable to perimeter fuel basket panels as discussed in Subsection 6.II.3.1.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.II-44 2.II.6 References

[2.II.1] 10 CFR Part 72, Licensing Requirements for the Independent Storage of Spent Fuel, High-level Radioactive Waste, and Reactor-Related Greater than Class C Waste, Title 10 of the Code of Federal Regulations- Energy, Office of the Federal Register, Washington, D.C.

[2.II.2] Holtec Report HI-2114830, "Final Safety Analysis Report on the HI-STORM FW MPC Storage System", NRC Docket No. 72-1032, Latest revision.

[2.II.3] ISG-2, Fuel Retrievability, Revision 0, USNRC, Washington DC

[2.II.4] ISG- 11, Cladding Considerations for the Transport and Storage of Spent Fuel, USNRC, Washington, DC, Revision 3, November 17, 2003.

[2.II.5] NUREG-0612, "Control of Heavy Loads at Nuclear Power Plants," United States Nuclear Regulatory Commission (1980)

[2.II.6] NUREG/CR-6407, Classification of Transportation Packaging and Dry Spent Fuel Storage System Components According to Importance to Safety, U.S. Nuclear Regulatory Commission, February 1996.

[2.II.7} ACI-318-05, Building Code Requirements for Structural Concrete (ACI 318-05) and Commentary (ACI 318R-05), Chapter 22, American Concrete Institute, 2005

[2.II.8] ASME Boiler & Pressure Vessel Code,Section III, Subsection NB. Class 1 Components, American Society of Mechanical Engineers, New York, NY, 2007

[2.II.9] ASME Code,Section III, Subsection NF and Appendix F, and Code Section II, Part D, Materials, 2007.

[2.II.10] ANSI N14.6-1993, "American National Standard for Radioactive Materials - Special Lifting Devices for Shipping Containers Weighing 10,000 Pounds (4500 Kg) or More", American National Standards Institute, Inc, Washington, DC, June 1993.

[2.II.11] Holtec Proprietary Position Paper DS-331, Structural Acceptance Criteria for the Metamic-HT Fuel Basket, Revision 4(USNRC Docket No. 71-9325) [NRC-reviewed in Docket # 72-1032]

[2.II.12] Metamic-HT Qualification Sourcebook, Holtec Report No. HI-2084122, (2010) (Holtec Proprietary).

[2.II.13] USNRC Regulatory Guide 3.61, "Standard Format for a Topical Safety Analysis Report for a Spent Fuel Storage Cask", USNRC, February 1989.

[2.II.14] USNRC Regulatory Guide 1.13, "Spent Fuel Storage Facility Design Basis", USNRC, March 2007.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.II-61 SUPPLEMENT 2.III

PRINCIPAL DESIGN CRITERIA FOR THE MPC-68M

2.III.0 OVERVIEW OF THE PRINCIPAL DESIGN CRITERIA

A general description of the MPC-68M is provided in Supplement 1.III. This supplement specifies the loading conditions and associated design criteria applicable to the MPC-68M fuel basket. The loads, loading conditions, and design criteria presented in Chapter 2 are applicable to the HI-STORM 100 System using the MPC-68M unless otherwise specified in this supplement. The drawing package for the MPC-68M fuel basket is provided in Section 1.5. The safety classifications of Metamic-HT basket and basket shims are ITS-A and NITS, respectively.

The design criteria pertaining to the HI-STORM overpack and the HI-TRAC transfer cask are completely unaffected by the incorporation of the MPC-68M. Likewise, the structural demands on the MPC Enclosure Vessel (whose design remains unchanged) are also unaffected. The design criteria in this supplement pertain to the loading conditions that bear upon the fuel baskets function and performance.

2.III.0.1 MPC-68M (Including MPC-68MCBS) Design Criteria

i. Structural

The fuel basket is designed to meet both stress and deformation a more stringent displacement limits under accident conditions of loading (credible and non-mechanistic)mechanical loadings than those implicit in the stress limits of the ASME code (see Section 2.III.2). The basket shims are designed to remain below the yield limit of the selected aluminum alloy. If used, fuel basket welds are designed and fabricated in accordance with Supplement 9.III and the drawing package in Section 1.5. Fuel basket structural welds are designed to the minimum weld strength specified in the drawing package in Section 1.5. Fuel basket welds are not used for the CBS design variant of the MPC-68M.

Metamic-HT is a Holtec proprietary (non-ASME code) material. The critical characteristics and the attainment of the required critical characteristics through a comprehensive qualification process and production testing are discussed in Supplement 1.III with acceptance criteria established in Supplement 9.III.

All normal and off-normal conditions (including pressures) for the MPC-68M and MPC-68MCBS are the same as those described in Section 2.2. All loads on the HI-STORM 100 overpack and HI-TRAC transfer cask described in Section 2.2 remain applicable when using the MPC-68M and MPC-68MCBS.

The main acceptance criterion for the evaluation of accident conditions on the MPC-68M and MPC-68MCBS fuel baskets areis for the basket structure to maintain the fuel contents in a subcritical configuration. The structural design criteria for the MPC-68M and MPC-68MCBS baskets are the

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.III-1

same as those described in Subsection 2.II.2.6 for the MPC-32M and MPC-32MCBSprovided in Table 2.III.4.

The maximum primary membrane plus bending stress in the fuel basket panels, within the active fuel region, must be below 90% of the ultimate strength of Metamic-HT material, on a true stress basis, at the applicable temperature. This primary stress limit, which is adopted from subparagraph F-1341.2 of the ASME Code [2.II.9], is the key determinant of the baskets structural integrity under accident conditions. Notwithstanding the stress criterion, an additional deflection limit is imposed on the Metamic-HT fuel baskets to ensure their structural integrity and criticality safety, which is defined below.

The fuel basket material is subject to the requirements in Supplement 1.III and is designed to a specific (lateral) deformation limit of its walls under accident conditions of loading (credible and non-mechanistic). The basis for the lateral deflection limit, , in the active fuel region, , is provided in [2.III.6.1] as

where is defined as the maximum average permanenttotal deflection sustained by the basket panels under the loading event and w is the nominal inside (width) dimension of the storage cell. Stated differently, is the maximum permanent deflection of a Metamic-HT panel averaged over the panel width, which is converted to a dimensionless parameter by dividing the average deflection by the unsupported panel width. The limiting value of is provided in Table 2.III.4, and it is also used conservatively to inform the criticality analysis model for the Metamic-HT fuel baskets, as described in Subsection 6.III.3. The above deflection-based criterion has been used previously in the HI-STAR 180 Transportation Package [2.III.6.2] to qualify similar Metamic -HT fuel baskets.

ii. Thermal

The design and operation of the HI-STORM 100 System with the MPC-68M must meet the intent of the review guidance contained in ISG-11, Revision 3 [2.0.8] as described in Subsection 2.0.1.

All applicable material design temperature limits in Section 2.2 and 4.3 continue to apply to the MPC-68M. Temperature limits of MPC-68M fuel basket and basket shim materials are specified in Table 4.III.2.

The MPC-68M is designed for both uniform and regionalized fuel loading strategies as described in Subsection 2.0.1. The regions for the MPC-68M are given in Table 2.III.1. Additionally, four quarter-symmetric heat load patterns have been defined for MPC-68M as shown in Figures 2.III.1 through 2.III.4. The same temperature limits apply to these configurations. Alternative heat load patterns may be developed following the methodology in the Topical Report HI-2200343-A [1.0.7].

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.III-2

additional fuel assembly array/classes which are added as acceptable contents to the MPC-68M only, 10x10F, 10x10G, 10x10I, 10x10J, and 11x11A. The maximum allowable initial enrichment for fuel assemblies are consistent with the criticality analysis described in Supplement 6.III.

Fuel classified as damaged fuel assemblies or fuel debris will be loaded into damaged fuel containers (DFCs) or basket cell locations with DFIs installed at the upper and lower ends. Fuel debris will be loaded into DFCs for storage in the MPC-68M. Damaged fuel assemblies stored with DFIs may contain missing or partial fuel rods and/or fuel rods with known or suspected cladding defects greater than hairline cracks or pinhole leaks as long as the fuel assembly can be handled by normal means and whose structural integrity is such that geometric rearrangement of fuel is not expected.

Damaged fuel that does not meet these conditions must be stored in a DFC. The appropriate thermal and criticality analyses have been performed to account for damaged fuel and fuel debris and are described in Supplements 4.III and 6.III, respectively. Figures 2.III.1 through 2.III.4 contain loading patterns for storage of fuel in the MPC-68M. The loading pattern in Figure 2.III.4, allows damaged fuel to be stored in inner locations. Non-fuel hardware is not applicable to all the BWR fuel classes/arrays.

The heat generation rate, axial burnup distribution, and all other bounding radiological, thermal, and criticality parameters specified for MPC-68 are used to ensure the performance of the HI-STORM SYSTEM with the MPC-68M.

2.III.2 MPC-68M DESIGN LOADINGS

Design loadings in Section 2.2 apply to the HI-STORM 100 System using the MPC-68M.

2.III.3 SAFETY PROTECTION SYSTEMS

Same as Section 2.3.

2.III.4 DECOMMISSIONING CONSIDERATION

Same as Section 2.4.

2.III.5 REGULATORY COMPLIANCE

Same as Section 2.5.

2.III.6 REFERENCES

[2.III.6.1] Holtec Proprietary Position Paper DS-331, Structural Acceptance Criteria for the Metamic-HT Fuel Basket, Revision 4(USNRC Docket No. 71-9325) [NRC-reviewed in Docket # 72-1032].

[2.III.6.2] HI-STAR 180 Transportation Package, USNRC Docket No. 71-9325.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.III-4

Table 2.III.4

STRUCTURAL DESIGN CRITERIA FOR THE FUEL BASKET PARAMETER ALLOWABLE VALUE Minimum service temperature -40ºF Maximum average permanenttotal (lateral) deflection 0.005 in the active fuel region, (dimensionless)

Refer to Subsection 2.III.0.1 for more information on deflection limit. Not applicable to perimeter fuel basket panels as discussed in Subsection 6.III.3.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 2.III-10

CHAPTER 2.IV: PRINCIPAL DESIGN CRITERIA

2.IV.0 Introduction

The principal design criteria for the HI-STORM 100 Version UVH canister storage system is unchanged in all respects except for those relating to its function related to limiting exposure of the overpack internal cavity to the external environment.

The Version UVH overpack does not have any open penetrations such as air vents in the classical design to permit ventilation of the ambient air and the Closure Lid is installed with a concentric gasket which inhibits the exchange of gas inside the cask with the ambient air. The Closure Lid is emplaced on the cask body with a set of large body bolts which are installed with a small axial clearance to allow any significant increase in internal gas pressure above the ambient pressure, to be relieved once it overcomes the counteracting lids weight. A simple force equilibrium shows that a pressure rise of 5 psi in the cask cavity is not possible to sustain even under the scenario of maximum density concrete installed in the casks lid. However, the structural evaluations are performed using a higher internal pressure.

The loadings associated with Version UVH must include internal pressure and external pressure which are not present in the ventilated cask. For all other Design Basis Loadings, Version UVH cask body is the same as the standard HI-STORM 100 cask body described in this FSAR. In this chapter, the Design pressures appropriate to Version UVH are defined and the overpack loadings are re-visited to ensure that the safety analyses presented in other chapters are comprehensive.

The ITS category of the Structures, Systems and Components (HI-STORM 100 UVH Overpack, MPCs, HI-TRACs) important-to-safety for the HI-STORM 100 UVH System are provided in the licensing drawings for the respective components as follow:

• HI-STORM 100 UVH Overpack: Licensing Drawing in Section 1.IV.5 of the Supplement

• MPC-32M: Licensing Drawing in Section 1.II.5 of Supplement II of this FSAR

• MPC-68M: Licensing Drawing in Section 1.5 of Chapter 1 of this FSAR

2.IV.0.1 Principal Design Criteria for the ISFSI Pad

The principal design criteria for the ISFSI pad applicable for the Version UVH cask remains unchanged from the main body of the FSAR with the exception of the requirements are identified in Table 2.IV.0.1.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Revision 25 2.IV-1

Table 2.IV.0.1

ISFSI Pad Requirements applicable for the Version UVH system

Item Allowable Value Thickness (inch) 30 Concrete Pad Compressive 5,000 (maximum)

Strength1 (psi)

Notes:

1 Compressive strength of concrete shall be determined based on 28-day break results, consistent with the guidance in NUREG-2215.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Revision 25 2.IV-2

Table 2.IV.2.1; Evaluation of the Mechanical Loadings for the Version UVH Storage Cask

Subsection in Applicable Loading Load Case the main report Case from Description where the Safety Consideration and Conclusion Table 2.2.14 loading is explained Moving Determine the flood velocity that will not overturn the Floodwaters overpack. Because the weight of the loaded cask is Moving slightly greater than the standard HI-STORM 100 4 Floodwater with 2.2.3.6 overpack, due to removal of the vent openings, the loaded HI- resistance to overturning will be slightly greater.

STORM on the Therefore, the admissible flood water velocity based pad on the standard overpack design is conservative.

Design Basis This case involves determining the maximum Earthquake magnitude of the earthquake that meets the acceptance (DBE) criteria of section 2.2.3.7. Because the outer diameter 4 Loaded HI- 2.2.3.7 (OD) and height of the CG of Version UVH cask are STORMs arrayed essentially identical to the reference cask analyzed in on the ISFSI pad Chapter 3, the discussion in Section 3.4.7 is applicable subject to ISFSIs to Version UVH cask.

DBE Strike by a Tornado-borne This criterion requires that the acceptance criteria of Missile 2.2.3.5 be met. The intermediate and small Design A large, medium Basis Tornado missiles are evidently satisfied by 4 or small tornado 2.2.3.5 Version UVH because it is structurally identical to the missile strikes a standard HI-STORM 100 cask, except for the absence loaded HI- of vent penetrations which is a positive structural STORM on the advantage for Version UVH. A stability analysis is ISFSI pad or a performed for the large design basis missile.

loaded HI-TRAC Non-Mechanistic Tip-Over Version UVHs response to the tip-over event is A loaded HI- analyzed in Chapter 3.IV to demonstrate that the 4 STORM is 2.II.2.2 acceptance criteria of 2.II.2.62 areis satisfied assumed to tip (applicable for both the MPC-32M and MPC-68M).

over and strike the pad.

Explosion The HI-STORM Version UVHs response to an explosion event is 4 is exposed to an 2.2.3.10 analyzed in Chapter 3.IV to demonstrate that the external pressure overpack is capable of withstanding the resulting resulting from an pressure differential.

explosion.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Revision 25 2.IV-14

2.IV.5 Safety Conclusions

The evaluations in this supplement show that:

• The loadings specified in Chapter 2 for the standard HI-STORM 100 ventilated overpacks, that are also applicable to the unventilated Version UVH overpack, are satisfied without additional analysis.

• Additional loadings - internal and external pressures have been identified for Version UVH that warrant analysis to demonstrate safety compliance with the acceptance criteria in this supplement.

• The non-mechanistic tip-over of a freestanding Version UVH system needs to be performed to demonstrate that the primary membrane plus bending stress in the basket panels and the permanentplastic deflection of the basket panels will not exceed the prescribed limits defined in Supplements 2.II and 2.III for the MPC-32M and MPC-68M, respectively.

• A handling accident is not credible for the Version UVH through the use of single failure proof lifting devices.

• A thermal analysis of the Version UVH is warranted to ensure peak cladding temperature remains below ISG-11 limits.

• All other components of the Storage system are unaffected by the choice of the version of the overpack employed in the Storage system.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Revision 25 2.IV-21

• The closure system for the MPCs consists of two components, namely, the MPC lid and the closure ring. The MPC lid can be either a single thick circular plate continuously welded to the MPC shell along its circumference or two dual lids welded around their common periphery. The MPC closure system is shown in the design drawings in Section 1.5. The MPC lid is equipped with vent and drain ports which are utilized for evacuating moisture and air from the MPC following fuel loading, and subsequent backfilling with an inert gas (helium) at a specified mass.

The vent and drain ports are covered by a cover plate and welded before the closure ring is installed. The closure ring is a circular annular plate edge-welded to the MPC lid and shell. The two closure members are interconnected by welding around the inner diameter of the ring. Lift points for the MPC are provided in the MPC lid.

• The MPC fuel baskets consist of an array of interconnecting plates. The number of storage cells formed by this interconnection process varies depending on the type of fuel being stored. Basket designs containing cell configurations for PWR and BWR fuel have been designed and are explained in detail in Section 1.2. All baskets are designed to fit into the same MPC shell. Welding of the basket plates along their edges essentially renders the fuel basket into a multiflange beam. Figure 3.1.1 provides an isometric illustration of a fuel basket for the MPC-68 design.

• The MPC basket is separated from its basket supports (basket shims) by a gap. The gap size decreases as a result of thermal expansion (depending on the magnitude of internal heat generation from the stored spent fuel). The provision of a small gap between the basket and the basket support structure is consistent with the natural thermal characteristics of the MPC. For MPCs that contain basket shims welded to the MPC basket, the MPC shell wall is separated from the basket shims by a gap.

The planar temperature distribution across the basket, as shown in Section 4.4, approximates a shallow parabolic profile. This profile will create high thermal stresses unless structural constraints at the interface between the basket and the basket support structure (or between the MPC shell wall and the basket shims) are removed.

• The MPCs will be loaded with fuel with widely varying heat generation rates. The basket/basket support structure (or MPC shell/basket shim or MPC shell/Extruded Shim/basket) gap tends to be reduced for higher heat generation rates due to increased thermal expansion rates. These aforementioned gaps are specified to be sufficiently large such that a gap exists around the periphery after any thermal expansion but are not excessively large so as to hinder the performance of the design functions of the MPC.

• In some early vintage MPCs, a small number of flexible thermal conduction elements (thin aluminum tubes) are interposed between the basket and the MPC shell. The elements are designed to be resilient. They do not provide structural support for the basket, and thus their resistance to thermal growth is negligible.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3-12 documents is indicated in this HI-STORM 100 SAR for continuity in narration. A complete account of analyses and results for all load combinations for all four constituents parts is provided in Section 3.4 as required by Regulatory Guide 3.61.

In the following, the loadings listed as applicable for each situational condition in Table 2.2.14 are addressed in meaningful load combinations for the fuel basket, enclosure vessel, and the overpack.

Each component is considered separately.

Fuel Basket

Table 3.1.3 summarizes all loading cases (derived from Table 2.2.14) that are germane to demonstrating compliance of the fuel baskets to Subsection NG when these baskets are housed within HI-STORM 100 or HI-TRAC.

The fuel basket is not a pressure vessel; therefore, the pressure loadings are not meaningful loads for the basket. Further, the basket is structurally decoupled from the enclosure vessel. The gap between the basket and the enclosure vessel is sized to ensure that no constraint of free-end thermal expansion of the basket occurs. The demonstration of the adequacy of the basket -to -enclosure vessel (EV) gap is presented in Chapter 4to ensure absence of interference is a physical problem that must be analyzed.

The normal handling loads on the fuel basket in an MPC within the HI -STORM 100 System or the HI-TRAC transfer cask are identical to or bounded by the normal handling loads analyzed in the HI-STAR 100 FSAR Docket Number 72-1008.

Three accident condition scenarios must be considered: (i) drop with the storage overpack axis vertical; (ii) drop with the HI-TRAC axis horizontal; and (iii) storage overpack tipover. The vertical drop scenario is considered in the HI-STAR 100 FSAR.

The horizontal drop and tip-over must consider multiple orientation of the fuel basket, as the fuel basket is not radially symmetric. Therefore, two horizontal drop orientations are considered which are referred to as the 0 degree drop and 45 degree drop, respectively. In the 0 degree drop, the basket drops with its panels oriented parallel and normal to the vertical (see Figure 3.1.2). The 45-degree drop implies that the basket's honeycomb section is rotated meridionally by 45 degrees (Figure 3.1.3).

Enclosure Vessel

Table 3.1.4 summarizes all load cases that are applicable to structural analysis of the enclosure vessel to ensure integrity of the confinement boundary.

The enclosure vessel is a pressure vessel consisting of a cylindrical shell, a thick circular baseplate at the bottom, and a thick circular lid at the top. This pressure vessel must be shown to meet the primary stress intensity limits for ASME Section III Class 1 at the design temperature and primary plus secondary stress intensity limits under the combined action of pressure plus thermal loads.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3-23 3.II.1 Structural Loading Cases

Table 2.II.2.1 provides the mechanical loading cases for the HI-STORM Version E and Version E1 storage overpack and the HI-TRAC Version MS transfer cask and their content (enclosure with MPC 32M and Version 1 of MPC-32, MPC-32M CBS, and MPC-68 baskets). Subsection 2.II.2.2 provides the associated acceptance criteria. The allowable stress tables for steel and Alloy X materials in Chapter 3 in the main body of this FSAR are used in the stress analyses.

For Fuel Baskets made of Metamic HT, the stress and deflection based structural criteriaon are specified in Subsection 2.II.2applies as set forth in Supplement III (wherein MPC-68M, presently certified and widely deployed, made of Metamic HT has been qualified) as well as in the HI-STORM FW FSAR [3.II.25].

As described in Chapter 1.II, version CBS of the MPC-32M fuel basket replaces loose basket shims with continuous basket shims (CBS) bolted to basket panel extensions on the basket periphery. In normal operating condition, these shims are not subject to any significant loads. The only condition in which this shim configuration experiences significant loads is the non-mechanistic tipover event when the shim extension plates may be subject to cantilever loads. This loading, which bounds all other events including seismic loads, is considered in the tipover analysis presented in Subsection 3.II.4.4.2.iii.

3.II.2 Weights and Centers of Gravity

As stated in Chapter 1.II, the heights of the MPC enclosure, HI-STORM Version E, HI-STORM Version E1, MPC-68M (including MPC-68M CBS) and MPC-32M (including MPC-32M CBS) are dependent on the length of the fuel assembly. The minimum MPC cavity height (which determines the external height of the MPC) is set equal to the nominal fuel length (along with control components, if any) plus , where is between 1.5 (minimum), 2.0 (maximum), is increased above 1.5 so that the MPC cavity height is a full inch or half-inch number. Thus, for the most common PWR fuel (W 17 by 17) whose length including control components is 167.2,

= 1.8 so that the MPC cavity height, c, becomes 169. is provided to account for irradiation and thermal growth of the fuel in the reactor. The cavity heights of the HI-STORM Version E and Version E1 overpack and the HI-TRAC Version MS transfer cask are set greater than the MPC height by fixed amounts to account for differential thermal expansion and manufacturing tolerances. Table 3.II.2.1 provides the minimum height data on HI-STORM Version E, HI-STORM Version E1, HI-TRAC Version MS, and the MPC as the adder to the MPC cavity length, h.

The bounding weights of the loaded MPC containing reference SNF with and without water are provided in Table 3.II.2.2. All weights are nominal values computed using the Solidworks' computer code or using standard material density and geometric shapes for the respective subcomponents of the equipment.

As discussed in Section 1.II.2, the weight of the HI-TRAC Version MS transfer cask is maximized for a particular site to take full advantage of the plants crane capacity within the architectural HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-2 limitations of the Fuel Building. Accordingly, the thickness of the lead shield and outer diameter of the water jacket can be adjusted to maximize shielding gamma and neutron shielding, respectively. The weight of the empty HI-TRAC VERSION MS cask in Table 3.II.2.3 is provided for the reference PWR fuel and assumed lead and water jacket radial widths using its Solidworks' rendering shown in the Licensing drawing in Section 1.II.5. The Solidworks computed weight is converted into the corresponding nominal weight by increasing the computed weight by 3% and rounded up the next number ending in two zeros to account for potential mill-supplied plate over-thickness and excess weld sizes. HI-TRAC weight for other length, lead and water jacket widths combination may be readily obtained from the Solidworks' model.

Table 3.II.2.4 provides the reference weight of the HI-STORM overpack for storing the reference PWR fuel in MPC-32M and MPC-32M CBS on the ISFSI pad. The weight of the HI-STORM Version E and Version E1 overpack body is provided for two discrete concrete densities. The weight at any other concrete density can be obtained by linear interpolation. Similarly, the weight of the HI-STORM lid is provided for two discrete values of concrete density. The weight corresponding to any other density can be computed by linear interpolation.

The maximum and minimum locations of the centers of gravity (CGs) are presented (in dimensionless form) in Table 3.II.2.5. The radial eccentricity, , of a cask system is defined as:

( is dimensionless) where r is the radial offset distance between the CG of the cask system and the geometric centerline of the cask, and D is the outside diameter of the cask. In other words, the value of defines a circle around the axis of symmetry of the cask within which the CG lies (see Figure 3.II.2.1). All centers of gravity are located close to the geometric centerline of the cylindrical cask since the non-axisymmetric effects of the cask system and its contents are very small. The vertical eccentricity, , of a cask system is defined similarly as:

( is dimensionless)

Where v is the vertical offset distance between the CG of the cask system and the geometric center of the cask (i.e., cask mid-height), and H is the overall height of the cask. A positive value of indicates that the CG is located above the cask mid-height, and a negative value indicates that the CG is located below the cask mid-height. Figure 3.II.2.2 illustrates how is defined.

The values of and given in Table 3.II.2.5 are bounding values, which take into consideration material and fabrication tolerances. For a specific site, the Solidworks models from which the Licensing drawings are extracted can be used to obtain precise weight and CG data.

The weight information provided above shall be used for designing the lifting and handling ancillary for the HI-STORM cask components. In addition, tThe maximum C.G. height per Table 3.2.5 shall be used for the stability analysis of the loaded HI-STORM under DBE conditions unless a more accurate CG height is calculated on a site-specific basis. Using the weight data in the previously mentioned tables, Table 3.II.2.6 has been constructed to provide the bounding weights HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-3 For all fuel assemblies loaded into MPCs, with or without DFC/DFIs, the sum of the free axial space above the top of the fuel assembly (free axial space does not include DFC/DFI hardware) shall be less than 6. Where necessary, fuel shims shall be used to reduce the free axial space.

2) In MPCs where fuel spacers are utilized or previous HI-STORM 100 systems changing over to the MPC-32M and HI-STORM 100E, the fuel length, L , may be considered fuel

+ a required spacer.

Table 3.II.2.2: MPC Weight Data Item Nominal Weight in Comment pounds Enclosure Vessel 20,000 Water weight in the MPC assumes that (Alloy X) water volume displaced by the fuel is equal to the fuel weight divided by an Water in the MPC 13,300 average fuel assembly density of 0.396 (Specific Gravity = 1) lb/in3.

Bounding Weight of 32 56,000 Reference PWR Fuel Assemblies Water mass displaced in 24,100 the pool by a welded and closed MPC (Specific Gravity= 1)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-6

3.II.3 Mechanical Properties of Materials

The information provided in Section 3.32 in the main body of this FSAR remains valid and unchanged.

The mechanical properties for the fuel basket shims and the CBS bolted connections are provided in Section 3.III.3.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-12

The following assumptions are made in the analysis:

The intermediate missile and the small missile are assumed to be unyielding, and hence the entire initial kinetic energy is assumed to be absorbed by local yielding and denting of the cask surface.

No credit is taken for the missile resistance offered by the HI-TRACs water jacket shell.

It is assumed a priori that the small and intermediate missiles will penetrate the water jacket shell with no energy loss. Therefore, in the analysis 100% of the missile impact energy is applied directly to the HI-TRAC Version MS main outer shell. At trunnion locations, trunnion block has better penetration resistance than the lead it replaces, hence, HI-TRAC MS with trunnion option has better missile resistance and is not explicitly evaluated.

For missile strikes on the side and top lid of the overpack, the analysis credits the structural resistance in compression offered by the concrete material that backs the outer shell and the lid.

The resistance from the concrete is conservatively assumed to act over an area equal to the target area of impact. In other words, no diffusion of the load is assumed to occur through the concrete.

The analyses documented in [3.II.23] and [3.II.24] shows that the depth of penetration of the small missile is less than the thinnest section of material on the exterior surface of the HI-STORM 100S Version E or Version E1 or the HI-TRAC Version MS. Therefore, the small missile will dent, but not penetrate, the cask. Likewise, the 1-inch missile cannot enter the air inlet/outlet vents in the HI-STORM 100S Version E and Version E1 overpack. The penetration results for the small and intermediate missile are summarized in Table 3.II.4.11 per [3.II.24] and [3.II.23].

For the intermediate missile, the analyses documented in [3.II.24] and [3.II.23] show that there will be no penetration through the concrete surrounding the inner shell of the storage overpack or penetration of the top lid. Likewise, the intermediate missile will not penetrate the lead surrounding the HI-TRAC Version MS inner shell. At trunnion locations, trunnion block offers better penetration resistance than the lead it replaces. Therefore, there will be no impairment to the Confinement Boundary due to tornado-borne missile strikes. Furthermore, since the HI-STORM 100S Version E and Version E1 and HI-TRAC Version MS inner shells are not compromised by the missile strike, there will be no permanent deformation of the inner shells and ready retrievability of the MPC will be assured.

(ii) Loading Case M-2; Vertical Free fall of Loaded cask:

Since the lifting devices and the cask appurtenances (lifting attachments on the cask) are designed to meet the single-failure proof criteria as per section 2.II.2.7, the vertical free fall of the HI-STORM cask and the horizontal fall of the HI-TRAC is not credible. If the lifting devices fail to meet the single failure proof criteria as per section 2.II.2.7, the postulated drops shall be addressed as part of the 10CFR72.212

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-27

evaluations. Such site-specific evaluation (if warranted) shall use the identical structural (finite element) models or evaluation methodologies as discussed in the following.

(iii) Loading Case M-3; Non-Mechanistic Tip-Over:

As discussed in Section 2.II.2.2, the non-mechanistic tip-over event applies to a loaded HI-STORM Version E and Version E1 module that is not anchored (or otherwise constrained from overturning on the ISFSI pad). The cask tip-over is not postulated as an outcome of any environmental phenomenon or accident condition. The cask tip-over is a non-mechanistic event, which is analyzed to comply with the guidance in NUREG-1536 [2.1.5]. The objective of the analysis is to demonstrate that the plastic deformation in the fuel basket is sufficiently limited to the value at which the criticality safety is maintained, retrieval of the fuel by normal means is assured, and that there is no significant loss of radiation shielding in the storage system.

The tip over event is an artificial construct wherein the HI-STORM 100S Version E or Version E1 overpack is assumed to be perched on its edge with its C.G. directly over the pivot point A (Figure 3.II.4.6)). In this orientation, the overpack begins its downward rotation with zero initial velocity.

Towards the end of the tip-over, the overpack is horizontal with its downward velocity ranging from zero at the pivot point (point A) to a maximum at the farthest point of impact. The angular velocity at the instant of impact defines the downward velocity distribution along the contact line.

In the following, an explicit expression for calculating the angular velocity of the cask at the instant when it impacts on the ISFSI pad is derived. Referring to Figure 3.II.4.6, let r be the length AC where C is the cask centroid. Therefore,

The mass moment of inertia of the HI-STORM Version E and Version E1 system, considered as a rigid body, can be written about an axis through point A, as

where Ic is the mass moment of inertia about a parallel axis through the cask centroid C, and W is the weight of the cask (W = Mg).

Let 1(t) be the rotation angle between a vertical line and the line AC. The equation of motion for rotation of the cask around point A, during the time interval prior to contact with the ISFSI pad, is

This equation can be rewritten in the form

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-28

which can be integrated over the limits 1 = 0 to 1 = 2f (Figure 3.II.4.6). The final angular velocity 1 at the time instant just prior to contact with the ISFSI pad is given by the expression

where, from Figure 3.II.2,

This equation establishes the initial conditions for the final phase of the tip-over analysis; namely, the portion of the motion when the cask is decelerated by the resistive force at the ISFSI pad interface. Using the data germane to HI-STORM Version E and Version E1 (Table 3.4.11) and the above equations, the angular velocity of impact is calculated as:

1 ( t B ) = 1. 48 rad/sec.

[

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HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-29

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Table 3.II.4.13 summarizes the stress results per [3.II.26], along with the corresponding material allowable stress.

In addition to the above analyses, an additional tipover analyseis areis performed for the HI-STORM Version E storage cask with loaded MPC-32MCBS and loaded MPC-68MCBS containing MPC-32M CBS basket using the same methodology as described above for the tipover analysis containing MPC-32M basket. The LS-DYNA model is constructed according to the dimensions specified in the licensing drawings included in Sections 1.II.5 and 1.III.5. The finite element models of the MPC-32MCBS and MPC-68MCBS baskets are shown in Figures 3.II.4.32A and 3.II.4.32B, respectively. The finite element models of the HI-STORM Version E overpack and the ISFSI are the same as described above, except Tthe bounding target foundation properties per Table 2.II.0.1 are utilized for the MPC-68MCBS tipover analysis. For the MPC-32MCBS tipover analysis, the pad characteristics are the same as the MPC-32M tipover analysis (i.e., 36 inch pad thickness and concrete compressive strength of 6,000 psi).

[

PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-32

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The complete details of the finite element model, input data and results are archived in the calculation package [3.II.26]. In summary, the results of the tipover analysesThe following conclusions demonstrate that all safety criteria are satisfied for the HI-STORM Version E cask system with MPC-32M CBS and MPC-68MCBS basket designs, which means:.

i. The maximum primary membrane plus bending stress in the fuel basket panels, within the active fuel region, does not exceed 90% of the true ultimate strength of Metamic-HT material at the applicable temperature per Subsection 2.II.2.6.

ii. The permanent lateral deflection of the most heavily loaded basket panel in the active fuel region complies with the deflection criterion in Table 2.II.2.4.

iii. [

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HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-33

iv. The plastic strains in the MPC enclosure vessel remain below the allowable material plastic strain limit.

v. The cask closure lid does not dislodge after the tipover event, i.e., the closure lid bolts remain in-tact.

vi. The closure lid does not suffer any gross loss of shielding.

i. The lateral deflection of the most heavily loaded basket panel in the active fuel region complies with the deflection criterion in Table 2.II.2.4.

ii. The CBS remain attached to the basket maintaining their physical integrity.

iii. The plastic strains in the MPC enclosure vessel remain below the allowable material plastic strain limit.

iv. The cask closure lid does not dislodge after the tipover event, i.e., the closure lid bolts remain in-tact.

v. The shielding capacity of overpack is not compromised by the tip-over accident and there is no gross plastic deformation in the overpack to affect the retrievability of the MPC.

Finally, tTipover analyses are also performed for the HI-STORM 100S Version E1 storage cask and 100S common lid with loaded MPC containing MPC-32M CBS and loaded MPC-68M CBS baskets and using the same methodology as described above for the HI-STORM 100S Version E tipover analyseis containing MPC-32M basket. The LS-DYNA model is constructed according to the dimensions specified in the licensing drawings included in Sections 1.II.5 and 1.III.5. The fully assembled tipover models for the MPC-32MCBS and the MPC-68MCBS inside the HI-STORM FW Version E1 overpack are shown in Figures 3.II.4.33A and 3.II.4.33B, respectively. The finite element models of the MPC-32MCBS and MPC-68MCBS baskets, which show the temperature zones associated with the HI-STORM Version E1, are shown in Figures 3.II.4.34A and 3.II.4.34B, respectively. The continuous basket shims are modelled using the same approach described above the HI-STORM Version E tipover analyses. Lastly, the finite element models of the ISFSI are the same as described above for the HI-STORM Version E tipover analyses, with the pad thickness and compressive strength conservatively increased to 36 inches and 6,000 psi, respectively, for the MPC-32MCBS.The bounding target foundation properties per Table 2.II.0.1 are utilized. The details of the finite element model, input data and results are archived in the calculation package

[3.II.26]. Based on the results in [3.II.26] all safety criteria listed above are satisfied. Tipover analyses are only performed with MPC-32M CBS and MPC-68M CBS Metamic-HT baskets as they are more prone to deflections due to reduced support from basket shims and the extended fuel basket panels outside the active fuel region. Tipover analyses for the governing cases are performed with both type of basket shim materials as discussed in Section 3.3.2.6. Comparative tipover evaluations of the other fuel basket variants, as permitted in Table 1.II.2.2, are presented in [3.II.26] and [3.A.7]. Structural qualification of HI-STORM 100S common lid under tipover is also presented in [3.II.26].

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Similar to the tipover results for the HI-STORM Version E, the response of the MPC-32MCBS and MPC-68MCBS baskets inside the HI-STORM Version E1 is predominantly elastic with very localized areas of plasticity. Nonetheless, to ensure compliance with the allowable limit in Subsection 2.II.2.6, the maximum permanent lateral deflection of the most heavily loaded CBS basket panels, at any elevation within the active fuel region, are obtained from the LS-DYNA solutions and reported in Table 3.II.4.15.

The complete details of the finite element model, input data and results are archived in the calculation package [3.II.26]. In summary, the results of the tipover analyses demonstrate that all safety criteria are satisfied for the HI-STORM Version E1 cask with MPC-32MCBS and MPC-68MCBS basket designs, which means:

i. The maximum primary membrane plus bending stress in the fuel basket panels, within the active fuel region, does not exceed 90% of the true ultimate strength of Metamic-HT material at the applicable temperature per Subsection 2.II.2.6.

ii. The permanent lateral deflection of the most heavily loaded basket panel in the active fuel region complies with the deflection criterion in Table 2.II.2.4.

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iv. The plastic strains in the MPC enclosure vessel remain below the allowable material plastic strain limit.

v. The cask closure lid does not dislodge after the tipover event, i.e., the closure lid bolts remain in-tact.

i.vi. The closure lid does not suffer any gross loss of shielding.

(iv) Loading Case M-5; Design Basis Earthquake: This loading case and corresponding acceptance criteria areis defined in Paragraph 2.II.2.2.

For a low intensity Design Basis earthquake, the two inequalities in Paragraph 2.II.2.2(c) provide the acceptance criteria.

In this section, the combination of vertical and horizontal ZPA of the earthquake that would cause incipient loss of kinematic stability is derived using static equilibrium. The resulting inequality defines the threshold of the so-called low intensity earthquake for which the HI-STORM 100S Version E and Version E1 system is qualified without a dynamic analysis.

For the purpose of performing a conservative analysis to determine the maximum ZPA that will not cause incipient tipping and relative sliding, the HI-STORM 100S VERSION E and Version E1 System is considered as a rigid body subject to a net horizontal quasi-static inertia force and a vertical quasi-static inertia force. This is consistent with the approach used in previously licensed HI-STORM dockets. The vertical seismic load is conservatively assumed to act in the most unfavorable direction (upwards) at the same instant. The vertical seismic load is assumed to be equal to or less than the net horizontal load with being the ratio of vertical component to one of the horizontal components.

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Table 3.II.4.12: Maximum Local True Plastic Strain Results

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Table 3.II.4.12: Intentionally Deleted

Table 3.II.4.12: Intentionally Deleted

Table 3.II.4.12: Intentionally Deleted Table 3.II.4.12A: Maximum Local True Plastic Strain Results

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Table 3.II.4.12B: Maximum Local True Plastic Strain Results

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Table 3.II.4.13: Minimum Safety Factor Results Item Induced stress Allowable Stress Safety Factor (ksi) (ksi)

Basket Panels 55.9 61.05 1.09 Weld between 4.15 9.19 2.21 basket Panels

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Table 3.II.4.14: Permanent Lateral Deflection of Fuel Basket Panels Due to Non-Mechanistic Tipover of HI-STORM Version E Overpack Fuel Basket Type Max. Calculated Allowable Limit Safety Factor Deflection, (in) (in)

MPC-32M 0.0370 0.04375 1.18 MPC-32MCBS 0.0277 0.04375 1.58 MPC-68MCBS 0.0277 0.03025 1.09 The following steps are taken to calculate the maximum permanent deflection of fuel basket panel from the results of the non-mechanistic tipover simulation for each basket type:

1) The effective stress and the plastic strain contours for the fuel basket are plotted in LS-DYNA at the time instant of maximum loading. The maximum load demand essentially corresponds to the time instant when the top end of the MPC and stored fuel assemblies bottom out inside the HI-STORM cavity after primary impact and begin to rebound in the upward direction.

2) The contour plots are visually examined to identify the specific panel locations and fuel basket elevations where the stresses/strains are maximum. Both horizontally and vertically oriented panels are considered.

3) At each of the identified locations, a row of elements spanning the width of the cell is selected.

4) For the selected row of elements, the total lateral displacement (elastic + plastic) at the middle of the span and at both ends of the span are obtained from the LS-DYNA solution. The relative deflection between the midspan of the panel and its two support ends is taken as the largest difference between the three absolute displacement measurements.

5) To separate the permanent deflection from the combined deflection, step (4) is repeated for the same row of elements for an earlier solution time step when the maximum stress in the limiting element (among the row of selected elements) is just below the yield strength of the material.

6) The maximum permanent deflection, for each panel location identified in step (3), is conservatively computed by subtracting the elastic deflection determined in step (5) from the total deflection (elastic +

plastic) determined in step (4).

7) (If necessary) To obtain maximum average permanent deflection over the panel width, steps (4) (5) and (6) are repeated for all elements along the selected span with respect to the closest end of the span.

Subsequently, the average of the calculated maximum plastic deflection for each element of the span is taken as the maximum average permanent deflection.

Calculated values are maximum permanent deflections at mid-span of basket panel (per steps 1 thru 6 above);

element averaging (per step 7 above) is not performed. Maximum calculated deflection also includes perimeter fuel basket panels.

Equal to 0.005 times the cell inner dimension per Subsection 2.II.2.6 and Table 2.II.2.4. Cell inner dimension obtained from drawing packages in Sections 1.5 and 1.II.5.

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Table 3.II.4.15: Permanent Lateral Deflection of Fuel Basket Panels Due to Non-Mechanistic Tipover of HI-STORM Version E1 Overpack Fuel Basket Type Max. Calculated Allowable Limit Safety Factor Deflection, (in) (in)

MPC-32MCBS 0.0294 0.04375 1.49 MPC-68MCBS 0.0267 0.03025 1.13 Maximum permanent deflection is calculated following the steps outlined in Table 3.II.4.14.

Calculated values are maximum permanent deflections at mid-span of basket panel (per steps 1 thru 6 in Table 3.II.4.14); element averaging (per step 7 in Table 3.II.4.14) is not performed. Maximum calculated deflection also includes perimeter fuel basket panels.

Equal to 0.005 times the cell inner dimension per Subsection 2.II.2.6 and Table 2.II.2.4. Cell inner dimension obtained from drawing packages in Sections 1.5 and 1.II.5.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-58

[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

Figure 3.II.4.8: LS-DYNA Tipover Model - HI-STORM Loaded with MPC

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-68

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Figure 3.II.4.11: LS-DYNA Model - MPC 32M Fuel Basket (note: the different colors represent regions with bounding temperatures of 360°C, 340°C, 325°C, 300°C, 285°C, 260°C, 250°C and 200°C, respectivelynote: the different colors represent regions with bounding temperatures of 365°C, 350°C, 325°C and 200°C, respectively)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-70

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Figure 3.II.4.14: Intentionally DeletedMaximum Plastic Strain - MPC 32M Fuel Basket

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-72

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Figure 3.II.4.15: Maximum Plastic Strain - MPC Enclosure Vessel

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-73

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Figure 3.II.4.16: Maximum Plastic Strain - HI-STORM Overpack (Excluding MPC Guide Tubes and Concrete)

[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

Figure 3.II.4.17: Maximum Plastic Strain - HI-STORM Overpack Closure Lid Bolts

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-74

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Figure 3.II.4.18: Maximum Plastic Strain - HI-STORM Overpack MPC Guide Tubes

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Figure 3.II.4.19: Maximum Plastic Strain - HI-STORM Overpack Lid (lid does not dislodge, and primary strains are within the failure limit of the material)

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Figure 3.II.4.20: Vertical Displacement Time History - ISFSI Concrete Pad Impacted by the HI-STORM (with Loaded MPC 32) Cask in a Tipover Accident

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Figure 3.II.4.21: Vertical Rigid Body Deceleration Time History - Fuel assemblies (Top of Fuel)

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Figure 3.II.4.32A: LS-DYNA Model - MPC-32MCBS Fuel Basket inside HI-STORM 100S Version E (note: the different colors represent regions with bounding temperatures of 360°C, 340°C, 325°C, 285°C, 260°C and 180°C, respectively)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-88

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Figure 3.II.4.32B: LS-DYNA Model - MPC-68MCBS Fuel Basket inside HI-STORM 100S Version E (note: the different colors represent regions with bounding temperatures of 355°C, 340°C, 325°C, 300°C, 285°C, 250°C, 200°C and 180°C, respectively)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-89

[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

Figure 3.II.4.33A: LS-DYNA Tipover Model - HI-STORM 100S Version E1 Loaded with MPC-32MCBS

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-90

[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

Figure 3.II.4.33B: LS-DYNA Tipover Model - HI-STORM 100S Version E1 Loaded with MPC-68MCBS

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-91

[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

Figure 3.II.4.34A: LS-DYNA Model - MPC-32MCBS Fuel Basket inside HI-STORM 100S Version E1 (note: the different colors represent regions with bounding temperatures of 360°C, 340°C, 325°C, 285°C, 260°C and 180°C, respectively)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-92

[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

Figure 3.II.4.34B: LS-DYNA Model - MPC-68MCBS Fuel Basket inside HI-STORM 100S Version E1 (note: the different colors represent regions with bounding temperatures of 355°C, 340°C, 325°C, 300°C, 285°C, 270°C, 250°C, 200°C and 180°C, respectively)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-93

System at a Nuclear Power Plant, USNRC, Washington D.C., 2007.

[3.II.17] "Construction of True-Stress-True-Strain Curves for LS-DYNA Simulations,"

Holtec Proprietary Position Paper DS-307, Revision 2.

[3.II.18] Adkins, H.E., Koeppel, B.J., Tang, D.T., Spent Nuclear Fuel Structural Response When Subject to an End Drop Impact Accident, Proceedings ASME/JSME Pressure Vessels and Piping Conference, PVP-Vol. 483, American.

[3.II.19] Dr. Ing. S.F. Hoerner, Fluid Dynamic Drag, 1965.

[3.II.20] EPRI NP-440, Full Scale Tornado Missile Impact Tests, 1977.

[3.II.21] Bechtel Topical Report BC-TOP-9A, Design of Structures for Missile Impact, Revision 2 (September 1974).

[3.II.22] 10CFR71, Waste Confidence Decision Review, USNRC, September 11, 1990.

[3.II.23] Structural Calculation Package for HI-STORM 100S Version E System, Holtec Report No. HI-2188402, Revision 2.

[3.II.24] Tornado Missile Analysis for HI-STORM 100S Version E System, Holtec Report No. HI-2188390, Revision 2.

[3.II.25] HI-STORM FW FSAR, Holtec Report No.2114830, latest Revision.

[3.II.26] Analysis of the Non-Mechanistic Tipover Event of the Loaded HI-STORM 100S Version E Storage Cask, Holtec Report No. HI-2188448, Revision 45.

[3.II.27] NUREG/CR-6865, Parametric Evaluation of Seismic Behavior of Freestanding Spent Fuel Dry Storage Systems, 2005.

[3.II.28] Regulatory Guide 1.60, Revision 2, July 2014, USNRC.

[3.II.29] Crane Manufacturer's Association of America (CMAA), Specification

1. 70, 1988, Section 3.3.

[3.II.30] NUREG/CR-6865, Parametric Evaluation of Seismic Behavior of Freestanding Spent Fuel Dry Cask Storage Systems, V. Luk, et. al., February 2005.

[3.II.31] Witte, M., et al., Evaluation of Low-Velocity Impacts Tests of Solid Steel Billet onto Concrete Pads, and Application to Generic ISFSI Storage Cask for Tipover and Side Drop, Lawrence Livermore National Laboratory, UCRL-ID-126295, Livermore, California, March 1997.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.II-102

SUPPLEMENT 3.III

STRUCTURAL EVALUATION OF THE MPC-68M AND MPC-68MCBS

3.III.0 OVERVIEW

In this supplement, the structural adequacy of the MPC-68M and MPC-68MCBS design variant is evaluated pursuant to the guidelines of NUREG-1536.

The organization of technical information in this supplement mirrors the format and content of Chapter 3 except that it only contains material directly pertinent to the MPC-68M and MPC-68MCBS.

The MPC-68M consists of a stainless steel (Alloy X) Enclosure Vessel, which is identical to that of the MPC-68, a BWR fuel basket made from Metamic-HT, and aluminum basket shims. In the CBS design variant of the MPC-68M, the aluminum baskets shims are bolted to basket panel extensions at the periphery of the basket. Section 1.III.2 contains a complete description of the MPC-68M components. Descriptions in this supplement regarding MPC-68M also apply to the MPC-68MCBS, unless otherwise noted.

The applicable codes, standards, and practices governing the structural analysis of the MPC-68M as well as the design criteria, are presented in Supplement 2.III. Throughout this supplement, the term safety factor is defined as the ratio of the allowable stress (load) or displacement for the applicable load combination to the maximum computed stress (load) or displacement. Where applicable, bounding safety factors are computed using values that bound the calculated results.

3.III.1 STRUCTURAL DESIGN

3.III.1.1 Discussion

A general discussion of the structural features of the MPC is provided in Subsection 3.1.1, and in general it applies to the MPC-68M with one notable exception. The MPC-68M fuel basket is qualified using a deflection-based acceptance criterion, as well as a stress criterion (see Subsection 2.III.0.1) as opposed to a stress-based criterion. The drawings of the MPC-68M fuel basket and MPC Enclosure Vessel are provided in Section 1.5.

3.III.1.2 Design Criteria

Same as in Subsection 3.1.2, including all of its paragraphs, except as modified in Subsection 2.III.0.1 for the MPC-68M fuel basket.

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3.III.2 WEIGHTS AND CENTERS OF GRAVITY

Since the weight density of Metamic-HT is significantly less than that of Alloy X, the MPC-68M weighs less than the MPCs listed in Table 3.2.1. The bounding weights for the MPC -68M are provided in Table 3.III.1.

The center of gravity (CG) height of the empty MPC-68M, and various other configurations involving the MPC-68M, is provided in Table 3.III.2.

3.III.3 MECHANICAL PROPERTIES OF MATERIALS

The strength properties of Metamic-HT have been characterized through a comprehensive test program, and Minimum Guaranteed Values suitable for structural design are provided in Supplement 1.III.

The fuel basket shims are made of an aluminum alloy ASTM B221 2219-T851 or ASTM B221 6063. Representative mechanical properties for the fuel basket shims are tabulated in Tables 3.III.3 and 3.III.3A. Strictly speaking, the shim is not a structural material because it does not withstand any tensile loads and is located in a confined space which would prevent its uncontrolled deformation under load. The simulation of the shim in the baskets structural model, however, utilizes its mechanical properties of which only the Yield Strength has a meaningful (but secondary) role. Accordingly, in this FSAR, the nominal value of the Yield Strength specified in Tables 3.III.3 and 3.III.3A herein, is set down as a critical characteristic for the shim material.

The minimum value of the Yield Strength reported in the material suppliers CoC must be at least 90% of the nominal value in the above referenced table to ensure that the non-mechanistic tip-over analysis will not have to be revisited. The simulation of the shim in the MPC-68MCBS baskets structural model utilizes a bilinear material model to capture plastic deformation. Since only extremely small plastic deformation is observed, only the Yield Strength has a meaningful (but secondary) role.

The attachment bolts and nuts connecting the continuous basket shims (CBS) to the extended panels of the MPC-68MCBS basket design, as presented on the applicable drawing in Section 1.5, are made of Alloy X. The nominal mechanical properties for the CBS bolts and nuts are tabulated in Table 3.3.1.

The function of the bolts is to maintain the axial connectivity of the basket panels during normal operations, and they do not experience any significant loads during the applicable mechanical loading scenarios under all conditions.

The mechanical properties for all other materials of construction are the same as in Section 3.3 (including all subsections and tables).

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-2

3.III.4.4.2 Differential Thermal Expansion

The material presented in Supplement 4.III demonstrates that a physical interference between discrete components of the MPC-68M (e.g., fuel basket and enclosure vessel) will not develop due to differential thermal expansion during any operating condition.

3.III.4.4.3 Stress Calculations

The majority of the stress calculations reported in Paragraph 3.4.4.3 are unaffected by or bound the addition of the MPC-68M and its CBS varient to the HI-STORM 100 System for the following reasons:

i. the MPC-68M does not require any changes to the HI-STORM overpacks or the HI-TRAC transfer casks for loading operations or long-term storage;

ii. the MPC-68M utilizes the same MPC Enclosure Vessel design as all MPCs;

iii. the fully loaded weight of the MPC-68M (Table 3.III.1) is less than the bounding MPC weight analyzed in Chapter 3 (Table 3.2.1);

Therefore, the stress calculations reported in Paragraph 3.4.4.3 are not repeated here unless material, geometry, or load changes warrant new analysis or discussion. In other words, unless a new analysis is presented in this subsection, the results in Paragraph 3.4.4.3 for the HI-STORM 100 System are also valid for the MPC-68M either inside the HI-STORM overpack or the HI-TRAC transfer cask.

3.III.4.4.3.1 Analysis of Load Cases F.3.b and F.3.c (Table 3.1.3)

During a non-mechanistic tip-over event, the fuel assemblies exert a lateral force on the fuel basket panels as the overpack impacts the ground and decelerates. The lateral force causes the fuel basket panels to deflect potentially affecting the spacing between stored fuel assemblies. To maintain the fuel in a subcritical configuration, aboth stress and deflection limits for the fuel basket panels areis set in Subsection 2.III.0.1, which is supported by the criticality safety analysis in Supplement 6.III.

Here a finite element analysis is performed using ANSYS to demonstrate that the maximum lateral deflection in the fuel basket panels under a bounding deceleration of 60g is less than the limit specified in Section 2.III.0.1. The 60g input deceleration is bounding because it exceeds the design basis deceleration limit of 45g for the non-mechanistic tip over of the HI-STORM storage overpack (see Subsection 3.III.4.10) and for the horizontal drop of the HI-TRAC transfer cask (see Subsection 3.4.9), and is equal to the design basis lateral deceleration limit of 60g for the HI-STAR transport cask [1.1.3] for future considerations. The analysis methodology presented in this subsection is identical to the methodology used in [2.III.6.2] to qualify the F-37 fuel basket.

[

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-5

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An initial LS-DYNA finite element model is developed to simulate the postulated tip-over event of HI-STORM 100 storage cask with loaded MPC-68M containing Metamic-HT basket. The LS-DYNA model is constructed according to the dimensions specified in the licensing drawings included in Section 1.5. Because of geometric and loading symmetries, a half model of the loaded cask and impact target (i.e., the ISFSI pad) is considered in the analysis.

[

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The LS-DYNA models for the HI-STORM 100 overpack and ISFSI pad are the same models used previously to perform the tipover analysis for the Alloy X fuel baskets (i.e., MPC-32, MPC-68) in Subsection 3.4.10. Similar to the Alloy X fuel baskets, the tipover analyses performed in this supplement for the MPC-68M and MPC-68MCBS consider two reference ISFSI pad designs, namely Set A and Set B, as set forth in Table 2.2.9. Since the HI-STORM 100 overpack, including its closure lid, have already been evaluated for the non-mechanistic tipover event in Section 3.4 with acceptable results, the focus of the tipover analyses performed herein is the qualification of the MPC-68M and MPC-68MCBS enclosure shells and fuel baskets (i.e., the cask internals). To evaluate the cask internals, detailed MPC and fuel basket models are constructed in LS-DYNA similar to those used in Supplement 3.II.

Figures 3.III.2 to 3.III.6 depict the finite-element tip-over analysis model developed for the HI-STORM 100 cask configuration with loaded MPC-68M. The orientation of the MPC-68M fuel basket in the tip-over analysis model (see Figure 3.II.4.2) is the so-called 0 degree orientation (see Figure 3.III.1). This orientation is chosen for analysis because it maximizes the lateral load on a single basket panel, which in turn maximizes the lateral deflection of the panel. In the 0º orientation, the amplified weight of each stored fuel assembly (during the 60g impact event) bears entirely on one basket panel. Conversely, in the 45º orientation, the amplified weight of each stored

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fuel assembly is equally supported by two basket panels. The difference in loading between these two basket orientations is pictorially shown in Figure 3.III.1, where m denotes the fuel assembly mass, a denotes the maximum lateral deceleration, and d denotes the enveloping size of the fuel assembly. For comparison purposes, the pressure loads on the basket panels are defined as p and q, respectively, for the 0º and 45º orientations. From the figure, the pressure load p that develops in the 0º orientation is 41% greater than the pressure load q that develops in the 45º orientation. Hence, the lateral deflection of a basket panel is much greater for the 0º orientation (which is why it is chosen for detailed analysis). It is also noted that the 90º corners where the basket panels intersect do not provide any additional moment resistance because of the slotted joint construction (see Figure 1.III.1); therefore, the 45º orientation (or any other orientation between 0º and 45º) does not give rise to any prying loads at the cell corners.

The fuel basket does not experience significant plastic deformation in the active fuel region to exceed the acceptable limits; plastic deformation is essentially limited locally in cells near the top of the basket beyond the active fuel region for MPC-68M basket. Nonetheless, to ensure compliance with the allowable limit in Subsection 2.III.0.1, the maximum permanent deflection of the most heavily loaded basket panel, at any elevation within the active fuel region, is obtained from the LS-DYNA solution and reported in Table 3.III.4. Note that the basket corner welds are not considered in the tip-over analysis for conservatism. The fuel basket is considered to be structurally safe since it can continue maintaining appropriate spacing between fuel assemblies after the tip-over event.

The MPC enclosure vessel experiences minor plastic deformation at the impact locations with the overpack channel guides; the maximum local plastic strain (8.2%, see Figure 3.III.7) is well below the failure strain of the material.

The complete details of the finite element model, input data and results are archived in the calculation package [3.III.6]. In summary, the results of the tipover analysis demonstrate that all safety criteria are satisfied for the HI-STORM 100 cask with MPC-68M basket design, which means:

i. The maximum primary membrane plus bending stress in the fuel basket panels, within the active fuel region, does not exceed 90% of the true ultimate strength of Metamic-HT material at the applicable temperature per Subsection 2.III.0.1.

ii. The permanent lateral deflection of the most heavily loaded basket panel in the active fuel region complies with the deflection criterion in Table 2.III.4.

iii. The stresses in the basket shims are mainly below the yield strength with only limited permanent deformation.

iv. The plastic strains in the MPC enclosure vessel remain below the allowable material plastic strain limit.

An additional tipover analyses are performed for the HI-STORM 100 storage cask with loaded MPC-68MCBS using the same methodology as described above for the tipover analysis containing MPC-68M basket. The LS-DYNA model is constructed according to the dimensions specified in

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-7

the licensing drawings included in Sections 1.5. The finite element model of the MPC-68MCBS basket is shown in Figure 3.III.8. The finite element model of the HI-STORM 100 overpack and the ISFSI are the same as described above

Similar to the MPC-68M basket design, the response of the MPC-68MCBS basket during the tipover event is predominantly elastic with very localized areas of plasticity. Nonetheless, to ensure compliance with the allowable limit in Subsection 2.III.0.1, the maximum permanent lateral deflection of the most heavily loaded CBS basket panels, at any elevation within the active fuel region, is obtained from the LS-DYNA solution and reported in Table 3.III.4.

The MPC enclosure vessel experiences minor plastic deformation at the impact locations with the overpack channel guides; the maximum local plastic strain (1.8%, see Figure 3.III.9) is well below the failure strain of the material.

The complete details of the finite element model, input data and results are archived in the calculation package [3.III.6]. In summary, the results of the tipover analyses demonstrate that all safety criteria are satisfied for the HI-STORM 100 cask with MPC-68MCBS basket design, which means:

i. The maximum primary membrane plus bending stress in the fuel basket panels, within the active fuel region, does not exceed 90% of the true ultimate strength of Metamic-HT material at the applicable temperature per Subsection 2.III.0.1.

ii. The permanent lateral deflection of the most heavily loaded basket panel in the active fuel region complies with the deflection criterion in Table 2.III.4.

iii. [

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]

iv. The plastic strains in the MPC enclosure vessel remain below the allowable material plastic strain limit.

As shown in Figure 3.III.1, a representative slice of the MPC-68M fuel basket, consisting of a smaller end section and a full section, is modeled in detail including the contained fuel assemblies and supporting basket shims. The fuel basket panels are modeled with SOLSH190 solid shell elements. The basket shims and each fuel assembly are modeled with SOLID45 solid elements.

The mass density assigned to the fuel assemblies corresponds to the maximum BWR fuel assembly weight per Table 2.1.22, except at the 16 cell locations along the basket perimeter where Damaged Fuel Containers are permitted. At these 16 locations, the mass density corresponds to the maximum weight of a BWR fuel assembly plus DFC per Table 2.1.22. Standard contact pairs using CONTA173/TARGE170 elements are defined at the interfaces of fuel assembly/basket panel, shim/basket panel, and between stacked basket panels including all the intersecting slot locations.

At the perimeter corners, the intersecting basket panels are bonded together in the finite element model, and the strength properties of the corner most elements are then adjusted depending on whether there is a full length weld at that location. At corner locations that are not welded full

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-8

length (see licensing drawing in Section 1.5), the elastic modulus of the corner elements is reduced to 1% of the MGV in Table 1.III.2 to effectively eliminate the joints shear and moment carrying capacity. The fuel basket material model is implemented with true stress-true strain multi-linear isotropic hardening plasticity model. An elastic material model is used for the basket shims since no plastic deformation is expected. To accommodate large plastic defo rmation in the fuel basket panels, sufficiently small element sizes (< 0.40 in) are used and 9 integration points through the thickness are specified. A sensitivity study was performed in [2.III.6.2] to confirm that the panel stresses and displacements obtained using solid shell elements are converged and comparable to those obtained using 5 solid elements through the thickness of the panel.

The FEA model of the MPC-68MCBS fuel basket is similar to that of the MPC-68M except for the following notable changes:

i. The solid basket shims and each fuel assembly are modeled with SOLID185 solid elements. Hollow basket shims are modeled with SOLSH190 solid shell elements.

SOLID185 is a general-purpose 3D solid element for material non-linearities and includes all the SOLID45 element formulations.

ii. The simulation of the shim in the MPC-68MCBS baskets structural model utilizes a bilinear material model to capture plastic deformation. Only small plastic deformation is observed, therefore, only the Yield Strength has a meaningful (but secondary) role.

iii. All bonded contacts and material modifications associated with welds are eliminated as the MPC-68MCBS fuel basket replaces loose basket shims with continuous basket shims (CBS) bolted to basket panel extensions on the basket periphery. Bolts are not explicitly modeled; however, shim/basket panels at bolted locations are bonded to replicate a bolted joint. Bolt holes in the Continuous Basket Shims and basket panel extensions are sized so that shims can slide up against basket panels without subjecting bolts to shear loads.

iv. At the eight perimeter corners, the intersecting basket panels are bonded together in the finite element model to model shim and bolts at these locations. Bolts at these perimeter corners are qualified using strength of material formulations.

The 60g deceleration is applied to the model with the basket in the so-called 0º orientation (see Figure 3.III.5). This orientation is chosen for analysis because it maximizes the lateral load on a single basket panel, which in turn maximizes the lateral deflection of the panel. In the 0º orientation, the amplified weight of each stored fuel assembly (during the 60g impact event) bears entirely on one basket panel. Conversely, in the 45º orientation, the amplified weight of each stored fuel assembly is equally supported by two basket panels. The difference in loading between these two basket orientations is pictorially shown in Figure 3.III.5, where m denotes the fuel assembly mass, a denotes the maximum lateral deceleration, and d denotes the enveloping size of the fuel assembly. For comparison purposes, the pressure loads on the basket panels are defined as p and q, respectively, for the 0º and 45º orientations. From the figure, the pressure load p that develops in the 0º orientation is 41% greater than the pressure load q that develops in the 45º

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-9

orientation. Hence, the lateral deflection of a basket panel is much greater for the 0º orientation (which is why it is chosen for detailed analysis). It is also noted that the 90º corners where the basket panels intersect do not provide any additional moment resistance because of the slotted joint construction (see Figure 1.III.1); therefore, the 45º orientation (or any other orientation between 0º and 45º) does not give rise to any prying loads at the cell corners. Finally, to ensure that the analysis for the 0º orientation is conservative and bounds all other basket orientations, the analysis is performed based on a lateral impact deceleration of 60g even though, according to the results presented in Section 3.III.4.10, the maximum impact deceleration due to the non -mechanistic tip over event (measured at the top of the overpack lid) is less than 45g.

The stress and strain distributions in the MPC-68M fuel basket panels at 60g are shown in Figures 3.III.2 and 3.III.3, respectively. The stress and strain distributions in the MPC-68MCBS fuel basket panels at 60g are shown in Figures 3.III.7 and 3.III.8, respectively. These figures show that the state of stress in the fuel basket panels is primarily elastic. The fuel basket displacements are plotted in Figures 3.III.4 and 3.III.9. Tables 3.III.4 and 3.III.5 compare the maximum lateral displacement in a fuel basket panel (relative to its end supports) with the deflection limit specified in Subsection 2.III.0.1.

Per the licensing drawing, the nominal width of fuel basket panels in the vertical direction may be increased or decreased provided that the length of the panel slots is increased or decreased proportionally. This means that the fixed-height fuel basket may be assembled using more (or fewer) panels than the number depicted on the licensing drawing. The results of the ANSYS static analysis for the fuel basket presented herein are valid for any panel width since (a) the lateral load on the fuel basket per unit (vertical) length remains the same and (b) the length of the slots measured as a percentage of the panel width remains the same.

Finally, to evaluate the potential for crack propagation and growth for the MPC-68M fuel basket under the non-mechanistic tipover event, a bounding crack propagation analysis is carried out in Attachment D of [1.III.A.3]. The analysis demonstrates that a through -thickness linear flaw measuring 1/32 inch in length (i.e., maximum undetectable flaw size per inspection criteria) remains stable under the most severe accident loading conditions.

The same finite element analysis is repeated for MPC-68MCBS with alternative basket shim material ASTM B221 6063. The only change made in the FEA is the basket shim material properties from ASTM B221 2219 to ASTM B221 6063. The material properties of ASTM B221 6063 are derived at a bulk temperature of 450 deg F from Table 3.III.3A

The stress and strain distributions in the MPC-68MCBS fuel basket panels using ASTM B221 6063 shim material are shown in Figures 3.III.7A and 3.III.8A, respectively. These results demonstrate that the state of stress in the fuel basket panels is primarily elastic. The fuel basket displacement is plotted in Figure 3.III.9A. Table 3.III.5A compares the maximum lateral displacement in a fuel basket panel (relative to its end supports) against the deflection limit specified in Subsection 2.III.0.1.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-10

The basket shims supporting the peripheral fuel basket panels are also shown to remain functional subsequent to the postulated drop event.

3.III.4.4.3.2 Elastic Stability and Yielding of the MPC-68M Fuel Basket under Compression Loads (Load Case F3 in Table 3.1.3)

Under certain conditions, the fuel basket plates may be under direct compressive load. Although the finite element simulations can predict the onset of an instability and post-instability behavior, the computation in this subsection uses (the more conservative) classical instability formulations to demonstrate that an elastic instability of the basket plates is not credible.

A solution for the stability of the fuel basket plate is obtained using the classical formula for buckling of a wide bar [3.III.1]. Material properties are selected corresponding to a metal temperature of 375ºC, which bounds the computed metal temperatures anywhere in the fuel basket (see Table 4.III.3). The critical buckling stress for a pin-ended bar is:

where h is the plate thickness, a is the unsupported plate length, E is the Youngs Modulus of Metamic-HT at 375ºC, is Poissons Ratio (use 0.3 for this calculation)

From the drawings in Section 1.5, h = 0.40 in, a = 6.05 in, and E = 6,125 ksi (Table 1.III.2). Then, the classical critical buckling stress is computed as 24.199 ksi, which exceeds the yield strength of the material (9.425 ksi) at 375ºC. This demonstrates that basket plate instability by elastic buckling is not possible.

3.III.4.5 Cold

Same as in Subsection 3.4.5.

3.III.4.6 HI-STORM 100 Kinematic Stability under Flood Condition (Load Case A in Table 3.1.1)

The stability evaluation of the HI-STORM 100 overpack under flood conditions in Subsection 3.4.6 bounds the scenario of a loaded MPC-68M inside a HI-STORM overpack. The previous analysis is bounding because it uses as input the empty weight of the HI-STORM overpack (i.e.,

no MPC inside) combined with the maximum CG height from Table 3.2.3.

3.III.4.7 Seismic Event and Explosion

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-11

3.III.8 REFERENCES

[3.III.1] Buckling of Bars, Plates, and Shells, D.O. Brush and B.O. Almroth, McGraw-Hill, 1975, p.22.

[3.III.2] Properties of Aluminum Alloys, Tensile, Creep, and Fatigue Data at High and Low Temperatures, ASM International, November 2006.

[3.III.3] ASME Boiler & Pressure Vessel Code,Section II, Parts A and D, American Society of Mechanical Engineers, 2007.

[3.III.4] Deleted.

[3.III.5] ASTM Specification B221M-07, Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes (Metric).

[3.III.6] Analysis of the Non-Mechanistic Tipover Event of the Loaded HI-STORM 100 Storage Cask, Holtec Report No. HI-2240678, Revision 0.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-19

TABLE 3.III.3A ALTERNATIVE FUEL BASKET SHIM MATERIAL - NOMINAL MECHANICAL PROPERTIES

Aluminum Alloy (Al 6063)

Temp. oC (oF) S S E  %

y u Elongation 25 (75) 195 (28) 220 (32) 6.9 (10.0) 22 150 (300) 115 (17) 145 (21) 6.3 (9.2) 23.9 (13.3) 28 204 (400) 59 (8.5) 75 (11) 6.0 (8.7) 24.5 (13.6) 45 230 (450) 38 (5.5) 52 (7.5) 5.8 (8.4) 24.8 (13.8) 55 260 (500) 24 (3.5) 34 (5) 5.6 (8.1) 25.0 (13.9) 70 290 (550) 20.5 (2.95) 27.5 (4) 5.4 (7.8) 25.4 (14.1) 77.5

Definitions:

Sy = Yield Stress, MPa (ksi)

= Mean Coefficient of thermal expansion, cm/cm-ºC x 10-6 (in/in-ºF x 10-6)

Su = Ultimate Stress, MPa (ksi)

E = Young's Modulus, MPa x 104 (psi x 106)

Notes:

1. Source for E values is Table TM-2 of [3.III.3].

2. Source for is Table TE-2 of [3.III.3].

3. Source for Sy, Su, and % Elongation are obtained from page 174 of [3.III.2]. The listed values in both imperial and SI units are directly obtained from [3.III.2].

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TABLE 3.III.4 PERMANENT LATERAL DEFLECTION OF FUEL BASKET PANELS DUE TO NON-MECHANISTIC TIPOVER OF HI-STORM 100 OVERPACK

Fuel Basket Type Max. Calculated Allowable Limit Safety Factor Deflection, (in) (in)

Set A ISFSI Pad MPC-68M 0.0265 0.03025 1.14 MPC-68MCBS 0.0249 0.03025 1.22 Set B ISFSI Pad MPC-68M 0.0142 0.03025 2.13 MPC-68MCBS 0.0202 0.03025 1.49 Maximum permanent deflection is calculated following the steps outlined in Table 3.II.4.14.

Calculated values are maximum average permanent deflections across width of basket panel (per steps 1 thru 7 in Table 3.II.4.14). Maximum calculated deflection excludes perimeter fuel basket panels.

Equal to 0.005 times the cell inner dimension per Subsection 2.III.0.1 and Table 2.III.4. Cell inner dimension obtained from drawing packages in Section 1.5.

Refer to Table 2.2.9.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-24

TABLE 3.III.4 MAXIMUM DISPLACEMENT IN MPC-68M FUEL BASKET

Maximum Lateral Displacement in Fuel Basket Maximum Allowable Value Safety Factor Panel, (dimensionless) of (from Table 2.III.4)

(Note 1) 1.008 x 10-3 0.005 4.96

TABLE 3.III.5 INTENTIONALLY DELETED MAXIMUM DISPLACEMENT IN MPC-68M CBS FUEL BASKET WITH ASTM B221 2219 BASKET SHIMS

Maximum Lateral Displacement in Fuel Basket Maximum Allowable Value Safety Factor Panel, (dimensionless) of (from Table 2.III.4)

(Notes 1 and 2) 3.471 x 10-3 0.005 1.44

Notes:

1. See Subsection 2.III.0.1 for definition of .

2. The calculated fuel basket panel deflection is maximum at a cross-section while the acceptance criterion is based on average deflection over the width and length of a panel.

Therefore, the computed deflection value is very conservative.

3.

4.

5. TABLE 3.III.5A

6. MAXIMUM DISPLACEMENT IN MPC-68M CBS FUEL BASKET WITH ASTM B221 6063 BASKET SHIMS 7.

8. Maximum Lateral Displacement in Fuel Basket Panel, 9. Maximum Allowable (dimensionless) Value of (from 10. Safety Factor (Notes 1 and 2 Table 2.III.4) underneath Table 3.III.5)

11. 3.735 x 10-3 12. 0.005 13. 1.34 14.

15.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-25

FIGURE 3.III.1: FINITE ELEMENT MODEL OF MPC-68M FUEL BASKET

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-26

FIGURE 3.III.2: TRUE STRESS DISTRIBUTION IN MPC-68M FUEL BASKET UNDER 60G LOAD

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-27

FIGURE 3.III.3: PLASTIC STRAIN DISTRIBUTION IN MPC-68M FUEL BASKET UNDER 60g LOAD

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-28

FIGURE 3.III.4: DISPLACEMENT CONTOURS IN MPC-68M FUEL BASKET

UNDER 60g LOAD

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-29

m x a p

d

(a) 0º Orientation

m x a q q

(b) 45º Orientation

FIGURE 3.III.15: FUEL LOADING FOR 0º AND 45º BASKET ORIENTATIONS

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-30

FIGURE 3.III.6: FINITE ELEMENT MODEL OF MPC-68MCBS FUEL BASKET

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-31

FIGURE 3.III.7: TRUE STRESS DISTRIBUTION IN MPC-68MCBS FUEL BASKET

UNDER 60G LOAD - SHIM MATERIAL ASTM B221 2219

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-32

FIGURE 3.III.7A: TRUE STRESS DISTRIBUTION IN MPC-68MCBS FUEL BASKET UNDER 60G LOAD - SHIM MATERIAL ASTM B221 6063

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-33

FIGURE 3.III.8: PLASTIC STRAIN DISTRIBUTION IN MPC-68MCBS FUEL BASKET

UNDER 60g LOAD - SHIM MATERIAL ASTM B221 2219

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-34

FIGURE 3.III.8A: PLASTIC STRAIN DISTRIBUTION IN MPC-68MCBS FUEL BASKET UNDER 60g LOAD - SHIM MATERIAL ASTM B221 6063

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-35

FIGURE 3.III.9: DISPLACEMENT CONTOURS IN MPC-68MCBS FUEL BASKET UNDER 60g LOAD - SHIM MATERIAL ASTM B221 2219

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-36

FIGURE 3.III.9A: DISPLACEMENT CONTOURS IN MPC-68MCBS FUEL BASKET UNDER 60g LOAD - SHIM MATERIAL ASTM B221 6063

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-37

[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

FIGURE 3.III.2 LS-DYNA Tipover Model - HI-STORM 100 Loaded with MPC-68M for both Set A and Set B

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-38

[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

FIGURE 3.III.3 LS-DYNA Model - MPC-68M Enclosure Vessel

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-39

[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

FIGURE 3.III.4 LS-DYNA Model - MPC-68M Fuel Basket (note: the different colors represent regions with bounding temperatures of 360°C, 350°C, 335°C, 325°C, 310°C, 290°C, 280°C and 200°C, respectively)

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[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

FIGURE 3.III.5 LS-DYNA Model - MPC 68M Fuel Basket Shims and Shim Plate

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[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

FIGURE 3.III.6 LS-DYNA Model - BWR Fuel Assemblies

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[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

FIGURE 3.III.7: Maximum Plastic Strain - MPC-68M Enclosure Vessel

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-43

[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

FIGURE 3.III.8 LS-DYNA Model - MPC-68MCBS Fuel Basket (note: the different colors represent regions with bounding temperatures of 355°C, 340°C, 325°C, 300°C, 285°C, 270°C, 260°C, 200°C and 180°C respectively)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-44

[PROPRIETARY INFORMATION WITHHELD PER 10CFR2.390]

FIGURE 3.III.9: Maximum Plastic Strain - MPC-68M Enclosure Vessel

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 3.III-45

3.IV.1 Structural Loading Cases

Table 2.IV.2.1 provides the mechanical loading cases for the HI-STORM 100 Version UVH storage overpack and their content (enclosure with MPC-32M and MPC-68M baskets). Subsection 2.IV.2 provides the associated acceptance criteria. The allowable stress tables for steel and Alloy X materials in Chapter 3 in the main body of this FSAR [3.IV.1] are used in the stress analyses.

For Fuel Baskets made of Metamic HT, the stress and deflection based structural criteriaon applies asare set forth in Subsection 2.II.2.6 Table 2.2.11 of the HI-STORM FW FSAR [3.IV.2].

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-2

The storage system is evaluated for the non-mechanistic tip-over using the same methodology and acceptance criteria used to evaluate HI-STORM Version EFW with MPC-32M in Supplement 3.IISubsection 2.2.3 of [3.IV.2].

This loading case described in Paragraph 2.2.3.2 applies to a loaded HI-STORM 100 Version UVH module that is not anchored (or otherwise constrained from overturning on the ISFSI pad). The objective of the analysis is to demonstrate that the plastic deformation in the fuel basket is limited to the value at which the criticality safety is maintained, retrieval of the fuel by normal means is assured, and that there is no significant loss of radiation shielding in the storage system.

The tip over event is an artificial construct wherein the HI-STORM 100 Version UVH overpack is assumed to be perched on its edge with its C.G. directly over the pivot point A (Figure 3.IV.4.7).

In this orientation, the overpack begins its downward rotation with zero initial velocity. Towards the end of the tip-over, the overpack is horizontal with its downward velocity ranging from zero at the pivot point (point A) to a maximum at the farthest point of impact. The angular velocity at the instant of impact defines the downward velocity distribution along the contact line.

[

PROPRIETARY INFORMATION WITHHELD IN ACCORDANCE WITH 10CFR2.390

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[

PROPRIETARY INFORMATION WITHHELD IN ACCORDANCE WITH 10CFR2.390

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Table 3.IV.4.6, summarizes the maximum plastic strain results, along with the corresponding material failure stain. Further details pertaining this analysis are presented in [3.IV.15].

[

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]

3.IV.4.3.5 Snow Load

The stress analysis of the overpack lid under snow load condition is performed using ANSYS

[3.IV.9]. The finite element model used is essentially the same as shown in Figure 3.IV.4.1 apart from the loads and the boundary conditions. The normal snow pressure of 100 lb/ft2 is used per Table 2.2.8 of the FSAR [3.IV.1]. The resulting stress distribution in the steel structure of the overpack lid under the applied snow load is shown in Figure 3.IV.4.27. The maximum stresses and the corresponding safety factors are summarized in Table 3.IV.4.8 per [3.IV.10]. For conservatism, the maximum primary stress in the lid is compared against the primary membrane and primary bending stress limits per Subsection NF (class 3 structures) of the ASME Code for Level A conditions. The allowable stresses are taken at bounding temperature, which exceeds the maximum operating temperature for the overpack top lid under normal operating conditions.

3.IV.4.3.6 Design Basis Earthquake HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-17

Table 3.IV.4.8: Factor-of-Safety for HI-STORM 100 Version UVH Lid under snow load

Item Calculated Value Allowable Safety (ksi) Limit (ksi) Factor Lid Assembly - Primary Membrane 9.62 16.6 1.73 Stress Lid Assembly - Primary Membrane 9.62 24.9 2.59 Plus Bending Stress

Table 3.IV.4.9: Permanent Lateral Deflection of Fuel Basket Panels Due to Non-Mechanistic Tipover of HI-STORM Version UVH Overpack

Fuel Basket Type Max. Calculated Allowable Limit (in) Safety Factor Deflection (in)

MPC-32M 0.034 0.04375 1.29 MPC-68M 0.0271 0.03025 1.12 Maximum permanent deflection is calculated following the steps outlined in Table 3.II.4.14.

Equal to 0.005 times the cell inner dimension per Subsection 2.II.2.6 and Table 2.II.2.4. Cell inner dimension obtained from drawing packages in Sections 1.5 and 1.II.5.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-27

[

PROPRIETARY INFORMATION WITHHELD IN ACCORDANCE WITH 10CFR2.390

]

Figure 3.IV.4.9: LS-DYNA Tipover Model - HI-STORM Loaded with MPC

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-36

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Figure 3.IV.4.12: LS-DYNA Model - MPC 32M Fuel Basket (note: the different colors represent regions with bounding temperatures of 360°C, 345°C, 315°C, 295°C, 270°C, 250°C, 230°C and 215°C, respectivelynote: the different colors represent regions with bounding temperatures of 350°C, 325°C, 300°C and 275°C, respectively)

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Figure 3.IV.4.15 Intentionally Deleted: Maximum Plastic Strain - MPC 32M Fuel Basket

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Figure 3.IV.4.16: Maximum Plastic Strain - MPC 32M Enclosure Vessel

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Figure 3.IV.4.17: Maximum Plastic Strain - MPC 32M HI-STORM Overpack (Excluding Concrete)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-44

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Figure 3.IV.4.18: Maximum Plastic Strain - MPC 32M HI-STORM Overpack Closure Lid Bolts

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-45

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Figure 3.IV.4.19: Maximum Plastic Strain - MPC 32M HI-STORM Overpack Lid (lid is not be dislodged, and primary strains are within the failure limit of the material)

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PROPRIETARY INFORMATION WITHHELD IN ACCORDANCE WITH 10CFR2.390

Figure 3.IV.4.20 Intentionally Deleted: Finite element model of the cross-section for MPC-68M internals with Orientation No. 1 (0 degree)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-47

PROPRIETARY INFORMATION WITHHELD IN ACCORDANCE WITH 10CFR2.390

Figure 3.IV.4.21 Intentionally Deleted: Finite element model of the cross-section for MPC-68M internals with Orientation No. 2 (45 degree)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-48

PROPRIETARY INFORMATION WITHHELD IN ACCORDANCE WITH 10CFR2.390

Figure 3.IV.4.22 Intentionally Deleted: Maximum Plastic Strain - MPC 68M Fuel Basket

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-49

PROPRIETARY INFORMATION WITHHELD IN ACCORDANCE WITH 10CFR2.390

Figure 3.IV.4.23: Maximum Plastic Strain - MPC 68M Enclosure Vessel

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-50

PROPRIETARY INFORMATION WITHHELD IN ACCORDANCE WITH 10CFR2.390

Figure 3.IV.4.24: Maximum Plastic Strain - MPC 68M HI-STORM Overpack (Excluding Concrete)

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PROPRIETARY INFORMATION WITHHELD IN ACCORDANCE WITH 10CFR2.390

Figure 3.IV.4.25: Maximum Plastic Strain - MPC 68M HI-STORM Overpack Closure Lid Bolts

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-52

PROPRIETARY INFORMATION WITHHELD IN ACCORDANCE WITH 10CFR2.390

Figure 3.IV.4.26: Maximum Plastic Strain - MPC 68M HI-STORM Overpack Lid (The primary strains are within the material's failure limit; hence the lid will not dislodge,)

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-53

3.IV.6 References

[3.IV.1] HI-STORM 100 FSAR, Holtec Report No.2002444, latest Revision.

[3.IV.2] HI-STORM FW FSAR, Holtec Report No.2114830, latest Revision.

[3.IV.3] NUREG-0612, "Control of Heavy Loads at Nuclear Power Plants," United States Nuclear Regulatory Commission.

[3.IV.4] Regulatory Guide 3.61 (Task CE306-4) Standard Format for a Topical Safety Analysis Report for a Spent Fuel Storage Cask, USNRC, February 1989.

[3.IV.5] ASME Boiler & Pressure Vessel Code,Section III, Sub-section NB, 1995 Edition with addenda up to and including 2010.

[3.IV.6] ASME Boiler & Pressure Vessel Code,Section III, Sub-section NF, 1995 Edition with addenda up to and including 2010.

[3.IV.7] Crane Manufacturer's Association of America (CMAA), Specification#70, 1988, Section 3.3.

[3.IV.8] Structural Calculation Package for HI-STORM Overpack, Holtec Report No. HI-2012769, Revision 18.

[3.IV.9] ANSYS 17.1, ANSYS, Inc., 2016.

[3.IV.10] Structural Calculation Package for HI-STORM 100 Version UVH Storage Cask, Holtec Report No. HI-2210241, Revision 0.

[3.IV.11] Bechtel Topical Report BC-TOP-9A, Design of Structures for Missile Impact, Revision 2 (September 1974).

[3.IV.12] 10CFR71, Waste Confidence Decision Review, USNRC, September 11, 1990.

[3.IV.13] LS-DYNA, Version 971, Livermore Software Technology, 2006.

[3.IV.14] Witte, M., et al., "Evaluation of Low-Velocity Impacts Tests of Solid Steel Billet onto Concrete Pads, and Application to Generic ISFSI Storage Cask for Tipover and Side Drop," Lawrence Livermore National Laboratory, UCRL-ID-126295, Livermore, California, March 1997.

[3.IV.15] Analysis of the Non-Mechanistic Tipover Event of the Loaded HI-STORM 100 Version UVH Storage Cask, Holtec Report No. HI -2210290, Revision 32.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2002444 Proposed Rev. 25 3.IV-55

6.II.3 MODEL SPECIFICATION

6.II.3.1 Description of Calculational Model

Calculational models for the MPC-32M are generally the same as those described in Section 6.3 except for the different basket as noted below.

Figures 6.II.3-1 and 6.II.3-2 show representative cross sections of the criticality models for the MPC-32M basket. Figure 6.II.3-1 shows a single cell of the basket, while Figure 6.II.3-2 shows the entire MPC-32M basket. All calculations are performed with the bounding eccentric fuel positioning, where the fuel is placed closest to the center of the basket in each basket cell.

The basket shims of MPC-32M CBS basket is assumed as the same as that of the MPC -32M basket. This is considered acceptable and conservative since the amount of basket shims of MPC -32M CBS is less than the MPC-32M basket which may result in even higher neutron leakage.

To account for the potentially higher fuel density of higher enriched fuel, a conservative fuel stack density of 97.5% of the theoretical density (i.e. 10.96 g/cm3

• 97.5% = 10.686 g/cm3) is used in all analyses for the MPC-32M.

Variations of parameters, namely fuel density and temperature in the MPC-32M, were analyzed using CASMO5. The results are presented in Table 6.II.3.1 and show that the maximum fuel density and the minimum water temperature (corresponding to a maximum wate r density) are bounding. These conditions are therefore used in all further calculations.

The basket geometry can vary due to manufacturing tolerances and due to potential deflections of basket walls as the result of accident conditions. The basket tolerances are defined in [6.II.3.1]. The structural acceptance criterion for the basket during accident conditions is that the permanent deflection of the basket panels, defined as the maximum average across the width of any panel in the inner area of the basket (i.e. except for the panels on the periphery), is limited to a fraction of 0.005 (0.5%) of the panel width (see Chapter 23). Note that this criterion only applies to the axial section covering the active region of the fuel. Deformations outside the active region would be inconsequential from a criticality perspective, as those areas of the basket are conservatively omitted from the calculational models. Additionally, there are stress limits defined in Chapter 2. The analyses in Supplement 3.II demonstrate that permanent deformations of the basket walls during accident conditions are far below this limit. In the calculational model for the criticality analysesNevertheless, it is conservatively assumed that 2 adjacent cell walls in each cell are deflected to the maximum extent possible over their entire length and width, i.e. thatby reducing the cell ID is reduced by 0.5% of the cell width for every cell for MPC-32M and MPC-32M CBS cellsbaskets. This is considered sufficiently representative to model the maximum average deflection, since the condition is considered for all cells of the basket, and over the entire basket length, while the analyses in Chapter 3 show that permanent deflections as a result of accident conditions are only present in a few areas of the basket. This is also sufficient to allow excluding the panels on the basket periphery from the deflection criteria, since the lateral neutron loss in these areas would significantly reduce the impact of the deflections in those panels on reactivity, while large deflections in those panels are in fact prevented anyhow due to the stress limits. Overall, this modeling is therefore a conservative approach to model the basket from a criticality perspective, consistent with the limitations specified in Chapter 2. Further note that all evaluations considering potential deflections from accident conditions are still performed assuming a fully flooded MPC, while under such accident conditions the MPC would be internally dry. The calculated keff results (which do not include the bias, uncertainties, or calculational statistics), along with the selected dimensions, for a number of dimensional combinations are shown in Table 6.II.3.2. For the MPC-32M, the cell ID is checked for minimum (tolerance only), minimum with deformation, nominal and an increased value, and the wall thickness is checked for nominal and minimum values; for the MPC-32M CBS, only the minimum cell HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-STORM 100 FSAR Proposed Rev. 25 REPORT HI-2002444 6.II-22 6.III.3 MODEL SPECIFICATION

Calculational models for the MPC-68M are generally the same as those described in Section 6.3 except for the different basket as noted below.

Figures 6.III.3.1 and 6.III.3.2 show representative cross sections of the criticality models for the MPC-68M basket. Figure 6.III.3.1 shows a single cell of the basket, while Figure 6.III.3.2 shows the entire MPC-68M basket. All calculations are performed with eccentric fuel positioning, where the fuel is placed closest to the center of the basket in each basket cell. The wall thickness of the basket shims is modeled as 1 inch, while some of them are only 1/2 inch thick. This is conservative, since the model replaces water with aluminum, which reduces absorption and moderation outside of the basket.

To account for the potentially higher fuel density of higher enriched fuel, a conservative fuel stack density of 97.5% of the theoretical density (i.e. 10.96 g/cm3

• 97.5% = 10.686 g/cm3) is used in all analyses for the MPC-68M.

The basket geometry can vary due to manufacturing tolerances and due to potential deflections of basket walls as the result of accident conditions. The basket tolerances are defined on the drawings in Section 1.5. The structural acceptance criterion for the basket during accident conditions is that the permanent deflection of the basket panels, defined as the maximum average across the width of any panel in the inner area of the basket (i.e. except for the panels on the periphery), is limited to a fraction of 0.005 (0.5%) of the panel width (see Chapter 23). Note that this criterion only applies to the axial section covering the active region of the fuel. Deformations outside the active region would be inconsequential from a criticality perspective, as those areas of the basket are conservatively omitted from the calculational models. Additionally, there are stress limits defined in Chapter 2. The analyses in Supplement 3.III demonstrate that permanent deformations of the basket walls during accident conditions are far below this limit. In the calculational model for the criticality analysesNevertheless, it is conservatively assumed that 2 adjacent cell walls in each cell are deflected to the maximum extent possible over their entire length and width, i.e. thatby reducing the cell ID is reduced by 0.5% of the cell width , or 0.03 for every cell of the MPC-68M and MPC-68MCBS cellsbaskets. This is considered sufficiently representative to model the maximum average deflection, since the condition is considered for all cells of the basket, and over the entire basket length, while the analyses in Chapter 3 show that permanent deflections as a result of accident conditions are only present in a few areas of the basket. This is also sufficient to allow excluding the panels on the basket periphery from the deflection criteria, since the lateral neutron loss in these areas would significantly reduce the impact of the deflections in those panels on reactivity, while large deflections in those panels are in fact prevented anyhow due to the stress limits. Overall, this modeling is therefore a conservative approach to model the basket from a criticality perspective, consistent with the limitations specified in Chapter

2. Further note that all evaluations considering potential deflections from accident conditions are still performed assuming a fully flooded MPC, while under such accident conditions the MPC would be internally dry. Maximum keff results (including the bias, uncertainties, or calculational statistics),

along with the selected dimensions, for a number of dimensional combinations are shown in Table 6.III.3.1 for various fuel types. The cell ID is evaluated for minimum (tolerance only), minimum with deformation, nominal and an increased value. The wall thickness is evaluated for nominal and minimum values.

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