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Redacted - Calculation 1042-0205, Revision 1, 61BTH Itcp and Otcp Closure Weld Flaw Evaluation.
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L-MT-1 5-056 ENCLOSURE 4 AREVA CALCULATION 11042-0205, REVISION 1 TITLE:

6IBTH ITCP AND OTCP CLOSURE WELD FLAW EVALUATION 77 pages follow

CONTROLLED COPY E-203 A ACalculation TIP~or3 .2-RvIn10 Calculation Cover Sheet No.

Revision No.

11042-0205 I

A R E VA . Rvso 0 Page Iof 7 DCR NO (if applicable): PROJECT NAME: NUHOMSe 61BTH Type 1 DSCs for 11042022 Rv. 0Monticello Nuclear Generating Plant PROJECT NO: 11042 CLIENT: Xcel Energy CALCULATION TITLE:

61B8TH ITCP and OTCP Closure Weld Flaw Evaluation

SUMMARY

DESCRIPTION:

1) Calculation Summary This calculation qualifies Monticello DSC-16, a 61B8TH Type I DSC, for all design basis loads in consideration of observed flaws in the Inner Top Cover Plate (ITCP) and Outer Top Cover Plate (OTCP) closure welds.

2) Storage Media Location

- Coldstor -/areva...nh11042/I11042-0205-000 If original Yes El Issue, No is 0]

licensing (explainreview below)per TIP 3.5 required?

Licensing Review No.:

This calculation is prepared in support of license exemption request which will be reviewed and approved by the NRC. Therefore, licensing review per TIP 3.5 is not required.

Software utilized (subject to test requirements of TIP 3.3): Software Version: Software Log ANSYS14.0Revision R-29 Calculation is complete R..c,,* *0..o, ** "**":- Date:

Originator Name and Signature: Jeff Pieper c*y/c.-

o/1 Calculation has been checked for consistency, completeness, and correctness Date:

Checker Name and Signature: Gabdiel Lomas (2 "Y'

'* *./ 5 Calculation is approved aead*ntuse for USpoetEgne

***// ae*io/F

A Calculation No. 11042-0205 Revision No. 1 AREVA Calculation Page 2of77 REVISION

SUMMARY

Affected Affected Rev. Description Pages Data 0 Initial Issue All All 1-10, 13, Revised per DCR 11042-022 Revision 0. Made 14, 17, 18, Removed editorial clarifications, updated information from 21, 22, 24- etaeu revised Reference calculations, removed 34, 36, 45, da.

extraneous sensitivity analyses. 46, 48-50,da.

_______ ___________________________________ 59-77 _______

A Calculation No. 11042-0205 Revision No. 1 AREVA-- - Calculation Page 3of77 TABLE OF CONTENTS Page 1.0 PURPOSE...................................................................................................... 7 2.0 ASSUMPTIONS............................................................................................... 8 3.0 DESIGN INPUT/DATA........................................................................................ 9 3.1 DSC Geometry.......................................................................................... 9 3.2 Flaw Details and Geometry........................................................................... 10 3.2.1 Outer Top Cover Plate ....................................................................... 10 3.2.2 Inner Top Cover Plate........................................................................ 11 3.3 Material Properties .................................................................................... 13 3.4 Design Criteria......................................................................................... 13 4.0 METHODOLOGY ............................................................................................ 14 4.1 Analysis Method and Acceptance Criteria........................................................... 14 4.2 Load Cases ............................................................................................ 17 4.3 FEA Model Details .................................................................................... 21 4.3.1 Axisymmetric Case #1 ....................................................................... 23 4.3.2 Axisym metric Case #2 ....................................................................... 23 4.3.3 Axisym metric Case #0 ....................................................................... 23 4.3.4 Half-Symmetry (3D) Case #1 ......................................................... 24 4.3.5 Half-Symmetry (3D) Case #0 ................................................................ 26 4.4 Limit Load Solution Details ........................................................................... 26

5.0 REFERENCES

............................................................................................... 27 6.0 ANALYSIS.................................................................................................... 28 6.1 Axisymmetric Analyses for Internal Pressure ....................................................... 28 6.1.1 Axisymmetric Case #1 - Initial Mesh Model................................................ 28 6.1.2 Axisymmetric Case #1 - Refined Mesh Models............................................ 28 6.1.3 Axisymmetric Case #2 ....................................................................... 30 6.1.4 Axisym metric Case #0 ....................................................................... 30 6.2 Half Symmetry Analyses for Internal Pressure (Benchmark Cases) .............................. 31 6.3 Half Symmetry Analyses for Side Drop Loading .................................................... 32 6.3.1 Half-Symmetry Case #1...................................................................... 32 6.3.2 Half-Symmetry Case #0...................................................................... 33 6.4 Evaluation of the 25g Corner Drop................................................................... 33 7.0 DISCUSSION AND CONCLUSIONS....................................................................... 34 8.0 LISTING OF COMPUTER FILES........................................................................... 35 9.0 TABLES AND FIGURES .................................................................................... 37

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 4of77 LIST OF TABLES Page Table 1 - Summary of Design Basis Load Combinations for the 61 BTH DSC [Ref. 5.8]...................... 37 Table 2 - Internal Pressure in the 61 BTH Type I DSC ........................................................... 40 Table 3 - Maximum Temperatures in the 61BTH Type I DSC Shell ............................................ 40 Table 4 - Properties of SA-240 Type 304. [Ref. 5.111 ............................................................ 41 Table 5 -Properties of SA-36. [Ref. 5.111 .......................................................................... 42 Table 6 -Summary of Load Cases and Results.................................................................... 43

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 5of77 LIST OF FIGURES Page Figure 1 - Sketch of the 61BTH DSC Top End and Transfer Cask from Reference 5.1 ...................... 44 Figure 2 - Details of the 61BTH Top End Component Interfaces............................................... 45 Figure 3 - ITCP and OTCP Closure Weld Details from Reference 5.5......................................... 46 Figure 4 - DSC Top End Detailed Dimensions................................................................... 47 Figure 5 - OTCP Flaws - Raw Data from Reference 5.1........................................................ 48 Figure 6 - OTCP Flaws - Main Flaw Group Reduced and Bounded........................................... 48 Figure 7 - OTCP Flaws - Bounding Set #1 for ANSYS Collapse Analysis .................................... 49 Figure 8 - OTCP Flaws -Bounding Set #2 for ANSYS Collapse Analysis..................................... 49 Figure 9 - ITCP Flaws - Raw Data from Reference 5.1 ................ : ........................................ 50 Figure 10 - ITCP Flaws - Bounding Flaw Set for ANSYS Collapse Analysis ................................. 50 Figure 11 - Overview of the Axisymmetric Model ................................................................ 51 Figure 12 - Mesh Details Near the Lid Regions of the Axisymmetric Model................................... 51 Figure 13 - Mesh Details at the Welds for Axisymmetric Case #1.............................................. 52 Figure 14 - Flaw Locations for Axisymmetric Case #1........................................................... 52 Figure 15 - Refined Mesh (Weld Region) for Axisymmetric Case #1........................................... 53 Figure 16 - Refined Mesh (Weld and Lid Interior Region) for Axisymmetric Case #1......................... 53 Figure 17 - Mesh Details at the Welds for Axisymmetric Case #2.............................................. 54 Figure 18 - Flaw Locations for Axisymmetric Case #2 .......................................................... 54 Figure 19 - Overview of the Half-Symmetry Model .............................................................. 55 Figure 20 - Detail Views and Mesh Plots of the Half Symmetry Model......................................... 56 Figure 21 - Isometric Views of Half-Symmetry Model ........................................................... 57 Figure 22 - Isometric Views of Half-Symmetry Model (Refined Circumferential Mesh)....................... 58 Figure 23 - Results for Axisymmetric Case #1 - Initial Mesh - Service Level A/B............................ 59 Figure 24 - Deflection History of the Center of the OTCP for the Axisymmetric Case #1 Initial Mesh......60 Figure 25 - Results for Axisymmetric Case #1 - Refined Mesh in Weld Region - Service Level A/B......61 Figure 26 - Results for Axisymmetric Case #1 - Refined Mesh in Weld and Lid Interior Region - Service Level A/B ........................................................................................... 62 Figure 27 - Deflection History of the Center of the OTCP for the Axisymmetric Case #1 Refined Mesh....63 Figure 28 - Comparison of Maximum Displacement Histories for Axisymmetric Model Sensitivity Studies 64 Figure 29 - Comparison of Maximum Displacement Histories for Axisymmetric Model with Lid Contact Defined using Nodal DOF Couples vs. Contact Elements...................................... 65 Figure 30 - Comparison of Maximum Displacement Histories for Axisymmetric Model With and Without Pressure Loading Applied to the ITCP Weld Root Flaw Faces ................................. 66 Figure 31 - Results for Axisymmetric Case #2 - Refined Mesh in Weld and Lid Interior Region - Service Level A/B ........................................................................................... 67 Figure 32 - Results for Axisymmetric Case #0 - Refined Mesh in Weld and Lid Interior Region - Service Level A/B ........................................................................................... 68 Figure 33 - Comparison of Maximum Center-of-Lid Displacement Histories for the Various Flaw Models . 69 Figure 34 - Results for Half-Symmetry Case #1 Internal Pressure Loading Benchmark Analysis - Service Level A/B ........................................................................................... 70 Figure 35 - Benchmark of the Half Symmetry model with the Axisymmetric Analysis ........................ 71 Figure 36 - Equivalent Stress and Plastic Strain Plots from the Half-Symmetry #1 Side Drop Analysis....72 Figure 37 - Additional Results Plots from the Half-Symmetry #1 Side Drop Analysis......................... 73 Figure 38 - Equivalent Stress and Plastic Strain Plots from the Half-Symmetry #1 Side Drop Analysis with Off-Normal Internal Pressure ..................................................................... 74 Figure 39 - Equivalent Stress and Plastic Strain Plots from the Half-Symmetry #1 Side Drop Analysis with Refined Circumferential Mesh .................................................................... 75

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 6of77 Figure 40 - Equivalent Stress and Plastic Strain Plots from the Half-Symmetry #0 (No Flaws) Side Drop Analysis ............................................................................................. 76 Figure 41 - Comparison of Maximum Displacement Histories for the Various Half-Symmetry Analyses .... 77

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 7 of 77 1.0 PURPOSE The purpose of this calculation is to evaluate DSC-16 at the Monticelio Nuclear Generating Plant (MNGP) per ASME Section III criteria in consideration of flaws observed in the Inner and Outer Top Cover Plate (ITCP and OTOP) closure welds. The flaws are documented in the Reference 5.1 Phased Array Ultrasonic Testing (PAUT) inspection report. The canister is a 61BTH Type 1 design. The ASME Section III Code limits on primary stress are evaluated using the limit load analysis criteria prescribed in the Code.

A Calculation No. 11042-0205 Revision No. 1 ARE VA Calculation Page 8of77 2.0 ASSUMPTIONS

1. The ITCP weld to the siphon and vent block and the welds of the siphon and vent port cover plates are inaccessible for PAUT inspection. Approximately 11" are obscured due to the location of the siphon and vent block. It is assumed that the flaws observed in the ITCP-to-DSC shell weld are representative of the inaccessible region and that no larger or more bounding flaws exist at the weld to the siphon and vent block. Whereas the main circumferential lid-to-shell welds are made with an automated welding machine, some manual welding was performed around the siphon/vent block and ports.

Note that the bounding flaws evaluated in this analysis are treated as full circumferential flaws. In other words, it is not assumed that the siphon and vent block is free of flaws, but rather contains the same bounding flaws as the examined welds. The geometry of the siphon and vent block is not assumed in this analysis. It is assumed that the stresses in the circular configuration bound the stresses that would be computed for a configuration that explicitly includes the siphon and vent block.

2. The longitudinal seams in the canister shell caused attenuation in the PAUT energy beam at locations 24.3" to 24.8" and 129.5" to 130" [Ref. 5.1] that can potentially diminish the effectiveness of the examination in these half inch areas. These regions are considered limited examination zones. It is assumed that the flaws observed outside of these regions are representative, and that no larger or more bounding flaws exist in the regions behind the canister seam welds.

3. Note that flaws are identified in this calculation using the numerical flaw listings in the Reference 5.1 inspection report.

4. The flaws are considered to be planar cracks lying on circumferential planes, parallel with the longitudinal axis of the cask. (I.e. the crack tips are pointed in the axial directions of the cask). This is a conservative flaw orientation since the welds primarily resist normal stresses in the plane of the lids due to plate bending caused by DSC internal pressure. Also, during the side drop loading, normal stresses in the plane of the lids resist the ovalizing mode of shell deformation.

This flaw orientation is also conservative for through-thickness shear stresses in the lid welds since it maximizes the reduction in available shear area. (A flaw of equal length, but placed at an angle, would result in less reduction of the weld throat thickness).

5. Many of the flaws identified in the Reference 5.1 PAUT examination report lie in very similar locations within the weld cross section. As discussed in detail in Section 3.2, flaws that lie in similar radial and axial positions within the weld are considered bounded by a representative "group flaw." The locations and sizes of the "group flaws" are chosen conservatively to ensure they are bounding of the individual flaws.

6. The analysis is based on the nominal dimensions of the components as shown in the design drawings [References 5.3 and 5.4] including the as-fabricated radial gap between the outer diameter of the lids and the inner diameter of the DSC shell. Although weld shrinkage will close this gap during closure operations, the resulting compressive load path between the lids and shell is conservatively ignored. Further discussion is provided in Section 4.3.

7. Since the ITCP and OTCP welds were subject to volumetric inspection (PAUT), no stress allowable reduction factor is applied to the strength of the weld. The full yield strength (ASME Code minimum) of the weld metal (equal to the base metal, see Table 4) is used in the analysis.

A Calculation No. 11042-0205 Revision No. 1 AREVA Calculation Page 9of77

8. Residual stress due to welding is a secondary stress and therefore is not considered in the limit load analyses performed in this calculation, as the Section III Code does not require it in the limit load analysis.

3.0 DESIGN INPUTIDATA 3.1 DSC Geometry The 61BTH Type 1 DSC geometry is detailed in the Reference 5.3 and 5.4 drawings. The Reference 5.5 drawing shows the details for the final ITCP and OTCP closure field welds. Sketches from Reference 5.1 and details from References 5.3 and 5.4 are shown in Figure 1 through Figure 4.

The material for all structural components (DSC Shell, OTOP, and ITCP) is SA-240 Type 304 stainless steel.

The shied plug material is SA-36 carbon steel.

The DSC shell is 0.5" nominal thickness.

The ITCP is 0.75" nominal thickness. Per the Reference 5.5 drawing, it is welded to the DSC shell and vent/siphon block with a 3/16" groove weld. However, the ITOP lid groove (weld prep) is 0.25" minimum, and it was confirmed that the weld is also 0.25" [Ref. 5.1].

The OTOP is 1.25" nominal thickness. It is welded to the DSC shell with a 1/2" groove weld.

The ITOP and OTOP closure welds (with the exception of the ITOP welds around the vent/siphon block and the welds of the vent and siphon port cover plates) are made using the GTAW process with an automated welder. This is a non-flux type of weld. The vent/siphon block and the vent and siphon port cover plate welds are performed manually.

A Calculation No. 11042-0205 Revision No. 1 AREVA Calculation Page 10 of 77 3.2 Flaw Details and Geometry Various sets of bounding flaws are chosen for the detailed analyses based on the flaw dimensions in Reference 5.1 and the discussion below.

3.2.1 Outer Top Cover Plate 3.2.1.1 Case 1 Figure 5 shows all of the OTCP weld flaws from Reference 5.1 plotted on an outline of the DSC geometry.

Figure 6 shows a similar plot but with the main cluster of flaws bounded by a box, and showing a representative "group flaw" for this region. The longest flaw within the group region is 31.7" long and the tallest flaw is 0.14" high. Therefore, the bounding flaw for this region is taken as a full circumferential flaw, 0.14" in height.

Note that all flaws in the group region were reviewed to ensure that no two flaws in close circumferential proximity, considered as being joined, would produce a taller flaw. For example, OTCP Flaw #9 and OTCP Flaw #10 are within 0.17" of each other in the circumferential direction, but their combined height is only 0.47-0.38=0.09". Therefore these flaws, considered combined, are bounded by the 0.14" high group flaw.

The radial and axial positions of the bounding flaw were chosen to be at the center of the group region. This radial position is within the critical failure plane of the weld (i.e. a plane containing the minimum weld throat thickness of 0.5").

Figure 6 also shows additional information about the flaws outside of the group region. OTCP Flaw #2 is intermittent around the entire circumference of the DSC. Therefore this flaw, at 0.12" in height, is considered a full circumferential flaw. Since OTCP Flaw #14 is in close proximity to Flaw #2, it is conservatively considered joined to OTCP Flaw #2, and the combined flaw height is considered to be present around the entire circumference. The combined flaw height is determined based on the geometry to be 0.195".

As seen in Figure 6, OTCP Flaw #20 is remote from the group region and from OTCP Flaw #s 2 and 14.

OTCP Flaw #20 is only 0.32" in length, and only 0.07" in height. This flaw is separated from OTCP Flaw #19 by 0.36" in the circumferential direction and by 0.19" in the axial direction. It is separated from OTCP Flaw

21 by 1.66" in the circumferential direction and by 0.23" in the axial direction. Since extension of the flaws under the postulated loading is negligible (since only one cycle of the critical loads is applied) this flaw will not join with the adjacent flaws. Additionally, since OTCP Flaw #20 is much smaller than the critical surface flaw size of 0.29" from Reference 5.17, it is not considered explicitly in the FEA analyses and is considered bounded by the other modeled flaws which are very conservative.

Similarly, OTCP Flaw #3 is remote from all flaws with the exception of OTCP Flaw #2. However, OTCP Flaw

3 is very small, only 0.18" long and 0.09" tall. Inspection of the PAUT plots (see Page 22 of Reference 5.1) also shows that OTCP Flaw #2, which is considered as fully continuous in this analysis, is actually very intermittent at the circumferential position of OTCP Flaw #3. Furthermore, OTCP Flaw #3 is much smaller than the critical subsurface flaw size of 0.29" from Reference 5.17. Therefore, it is not considered explicitly in the FEA analyses and is considered bounded by the other modeled flaws which are very conservative.

Figure 7 shows the first bounding flaw set considered for the OTCP in the ANSYS collapse analyses.

A Calculation No. 11042-0205

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AR EVA Calculation Page 11 of 77 3.2.1.2 Case 2 The discussion above and the flaw locations shown in Figure 5 through Figure 7 are based primarily on the tabulated flaw data from Reference 5.1. Since OTOP Flaw #2 is intermittent around the circumference of the weld, a closer inspection of the PAUT scan images is performed, and an additional flaw set for the OTCP is created. In this additional case, the location of OTCP Flaw #2 is based on the PAUT scan image of the flaw at the circumferential position of OTCP Flaw #14, which is the only additional flaw that could be considered to interact with OTCP Flaw #2. Based on the PAUT scan images, the flaws are located as seen in Figure 8.

In this case the height of both Flaw #2 and Flaw #7 are estimated based on the PAUT scan images and are conservatively larger than the flaw heights tabulated in Reference 5.1.

3.2.2 Inner Top Cover Plate Figure 9 shows all of the ITCP weld flaws from Reference 5.1 plotted on an outline of the DSC geometry. All but two of the flaws are clustered in the region of the weld root at the inner surface of the DSC shell. Figure 10 shows the bounding flaw set considered for the ITCP in the ANSYS collapse analyses. Both the representative group flaw and ITCP Flaw #7 are considered to be full circumferential flaws. ITCP Flaw #11 is remote from all other flaws (in the circumferential direction) and is therefore considered bounded by the representative group flaw. The representative group flaw for the ITCP is conservatively placed at the tension side of the weld when resisting internal pressure.

All of the ITCP flaws documented in Reference 5.1 were reviewed to ensure that no two (or more) flaws, which are in close proximity to each other, could be considered as combined and therefore creating a more critical flaw. The following cases are considered in particular:

ITCP Flaw #2 and Flaw #3 are within 0.12" from each other in the circumferential position, but their maximum combined height (1.58-1.49 = 0.09") is bounded by the group flaw height of 0.09".

ITCP Flaw #5 and Flaw #8 partially overlaps with Flaw #6 in the circumferential direction and would have a combined height of 0.15". However, Flaw #5 (0.15" in length) and Flaw #8 (0.14" in length) are extremely small. Due to their overlap in the circumferential direction, their combined length would be only 0.16", and therefore would not affect the global or local stability of the weld. This very short region with a potential 0.15" high flaw is bounded by the full-circumferential representation of the modeled flaws.

ITCP Flaw #10 is within 0.04" of Flaw #12 in the circumferential direction. The individual flaws are 0.05" tall and 0.04" tall, respectively, and 0.49" long and 0.18" long, respectively. They are also separated in the axial direction by 0.09". Postulating a flaw from the bottom of Flaw #12 to the top of Flaw #10 would imply a height of 0.18". However, the combined-height region would be over a very short length and would not affect the global or local stability of the weld. Therefore this postulated combined flaw is considered bounded by the full-circumferential representation of the modeled flaws.

It is noted that based on Figure 9 and Figure 10, ITCP Flaw #7 appears to be in the base metal of the inner top cover plate. It is likely that the flaw is actually at the fusion / heat affected region between the weld metal

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 12 of 77 and the base metal. The ANSYS models used in this calculation place the flaw at 0.81" inward from the outer surface of the OSC shell whereas the tabulated data in Reference 5.1 places the flaw at 0.80" from the outer surface. The 0.01" discrepancy is considered negligible. The exact location of the flaw is not considered critical in light of the significant margin that is available (See Section 7.0) and the generally very conservative idealization of the flaws (i.e. full circumferential).

A Calculation No. 11042-0205 Revision No. 1 AREVA Calculation Page 13 of 77 3.3 Material Properties The material properties for the DSC structure are taken from Reference 5.11. The properties of the two materials of construction, SA-240 Type 304 stainless steel and SA-36 carbon steel, are provided in Table 4 and Table 5, respectively. The weld metal is considered to be composed of the same properties as the base metal, as the welds are made with the non-flux GTAW method [Reference 5.14] using bare metal ER308

(:stainless) filler material. The tensile strength of the ER308 electrode (80 ksi at room temperature [Ref.

5.15]) is slightly greater than the type 304 base metal (75 ksi at room temperature [Ref. 5.16]). The yield stress value of the weld metal is assumed to be equal to or greater than the base metal. Therefore, the treatment of the weld metal as being identical to the base metal is appropriate for the Section III limit load analyses performed in this calculation.

Temperatures used for material properties are discussed in Section 4.2 and are shown in Table 3.

Poisson's ratio for all modeled parts is taken as 0.29.

Weight density for SA-240 Type 304 is taken as 0.285 lb/in3 .

Weight density for SA-36 is taken as 0.284 lb/in 3.

3.4 Design Criteria All of the applicable design basis loading conditions are considered in accordance with the requirements of ASME Section III Subsection NB [Ref. 5.7]. Section 4.1 details the methods used to perform the code qualifications. Section 4.2 details the selection of the bounding load cases.

A Calculation No. 11042-0205 AR E VA Calculation Page 14 of 77 4.0 METHODOLOGY 4.1 Analysis Method and Acceptance Criteria The 61BTH DSC including the ITCP and OTCP welds are designed and analyzed per ASME Section III Subsection NB (the Code) [Ref. 5.7] in the Reference 5.2 calculation. The presence of the ITOP and OTCP weld flaws will cause high local stresses and complex stress fields that will render an elastic analysis (such as those performed in Reference 5.2) very difficult. Therefore, the flaws are explicitly included in the finite element models as "design features", and the applicable ASME code stress limits are evaluated as described below.

Primary Stress Limits In order to satisfy the primary stress limits of Reference 5.7 paragraphs NB-3221 .1, NB-3221 .2, and NB-3221.3, a Limit Analysis will be performed per Paragraph NB-3228.1. The acceptance criterion is that the specified loadings not exceed two-thirds of the lower bound collapse load, as determined using an ideally plastic (non-strain hardening) material model, with the yield stress set at a value of 1.5"Sm. This criterion is used for evaluation of the Service Level A and B load cases discussed in Section 4.2.

Note that Service Level C acceptance criteria are generally 20% greater than Service Level A criteria, per Paragraph NB-3224 of Reference 5.7. This information is used in the discussion in Section 4.2 to eliminate some non-critical load cases.

For the Service Level D loadings (accident level internal pressure and side drop), the rules of ASME Section Ill Appendix F Paragraph F-1341.3 [Ref. 5.9] are used, which indicate that the loads 'shall not exceed 90%

of the limit analysis collapse load using a yield stress which is the lesser of 2.3Srn and 0.7Su." This criterion is used for evaluation of the Service Level D load cases discussed in Section 4.2.

Note that the Service Level 0 criterion is essentially 2.1 times greater than the Service Level A/B criterion, as calculated below. This information is used in the discussion in Section 4.2 to eliminate some non-critical load cases.

At a temperature of 500 0 F, the limit load yield stress for SA-240 Type 304 for Service Levels A/B and 0 are 26.3 ksi and 40.3 ksi, respectively.

The code required safety factors against the lower bound collapse load as determined by the limit load analyses for Service Levels A/B and D are 1.5 and 1.11, respectively.

The ratio of the acceptance criteria is therefore: (4o.3x15 .1.

(26.3.1.1) =21

A Calculation No. 11042-0205 Revision No. I A REVA- - Calculation Page 15of77 Primary Plus Secondary Stress Limits The Code also prescribes limits on primary plus secondary stresses for Service Levels A and B [Ref. 5.7 Paragraph NB-3222.2]. Secondary stresses may be developed in the DSC due to differential thermal expansion of the interconnected parts and thermal gradients within the structure. The code stress limit for primary plus secondary stress (calculated on an elastic basis) is 3 Sm. However, as shown in Ref. 5.7 Figure NB-3222-1, rules for exceeding the 3Srn limit are provided in Paragraph NB-3228.5, which states that 'the 3Sm limit ... may be exceeded provided that the requirements of (a) through (f) below are met."

Requirement (a) states that "the range of primary plus secondary membrane plus bending stress intensity, excluding thermal bending stresses, shall be _<3Smn." This provision is related to the potential for "plastic strain concentrations" occurring in "localized areas of the structure", and the potential for these concentrations to affect the "fatigue behavior, ratcheting behavior, or buckling behavior of the structure" [Ref.

5.7 Paragraph NB-3228.1]. Requirements (b) through (d) are also limitations related to fatigue and thermal stress ratchet. As detailed in Section 10.5 of Reference 5.2, the DSC is exempt from fatigue analysis requirements since all of the criteria in NB-3222.4 of Reference 5.7 are satisfied. Similarly, since the 080 thermal loads are not cyclic in nature (other than small daily and seasonal fluctuations), thermal stress ratchet is not a concern. Therefore, the 3 Sin limit as it relates to fatigue is not applicable.

Requirement (e) requires that the component temperature be less than 800 °F for austenitic stainless steel.

The maximum DSC shell temperature (entire shell including the lid region) is 611 °F (See Table 3).

Therefore this requirement is satisfied.

Requirement (f) states that the material must have a specified yield stress to ultimate stress ratio of less than 0.8. For the 61 BTH OSC which used SA-240 Type 304 steel, the ratio is 30175 = 0.4. Therefore this requirement is satisfied.

Based on the discussion above (primarily the fact that cyclic conditions are not a design factor for the DSC),

there is no need to consider limits on primary plus secondary stresses. Therefore, thermal stresses are not included in this analysis.

Special Stress Limits In addition to the primary and primary plus secondary stress limits imposed by Reference 5.7, the Code. also imposes Special Stress Limits as detailed in paragraph NB-3227. The applicable special stress limits are discussed below in relation to the DSC top end cover plate welds.

Bearing Loads: There are no bearing loads affecting the ITCP and OTCP closure welds. Therefore this special stress limit is not applicable to this evaluation.

Pure Shear: Although the ITCP and OTCP closure welds are loaded in shear by internal pressure loading, the stress state is not pure shear due to the additional bending stresses. Paragraph NB-3227.2 of Reference 5.7 clarifies that this stress limit is applicable to "for example, keys, shear rings, screw threads."

Therefore this special stress limit is not applicable to this evaluation.

Progressive Distortion of Nonintegral Connections: The ITCP and OTCP closure welds are not nonintegral connections. Furthermore, there are no sources of cyclic loading that would cause progressive distortion of the D5C. Therefore this special stress limit is not applicable to this evaluation.

A Calculation No. 11042-0205 Revision No. 1 AR EVA- Calculation Page 16of77 Triaxial Stress: The purpose of the code limit on triaxial stress is to provide protection against failure due to uniform triaxial tension [Ref. 5.13 Chapter 4.5]. Internal pressure in the DSC and bending of the cover plates may cause tension in the weld in the radial and circumferential directions, but there is no source for tension in the axial direction. Therefore failure due to hydrostatic tension in the weld metal is not credible. Therefore this special stress limit is not applicable to this evaluation.

Fracture and Flaw Extension Although linear-type flaws have been identified in the structure, the critical failure mode of the welds is plastic collapse. Under one-time loading, elastic and plastic crack extension are not a concern for the very tough type 304 stainless steel materials of the DSC shell, OTOP, and ITCP. This conclusion is supported by ASME Section XI Article 0-4000 "Determination of Failure Model" [Ref. 5.10] which states that for austenitic wrought material and non-flux welds, "plastic collapse is the controlling failure mode." Note that the 61 BTH Type 1 DSC OTCP and ITCP closure welds are made with the GTAW method [Reference 5.14] which is a non-flux type of weld.

Additionally, there is no source for fatigue flaw extension. The only cyclic loads on the DSC are minor daily and seasonal temperature fluctuations. Therefore, cyclic fatigue growth of the flaws in not a credible phenomenon.

Based on the discussions above, limit load analysis of the DSC top cover plates and closure welds is sufficient to satisfy all of the applicable stress criteria of the Code [Ref. 5.71.

A Calculation No. 11042-0205

Revision No. 1 AR EVA Calculation Page 17 of 77 4.2 Load Cases Table 1 lists the design basis load combinations for the 61 BTH DSC. This calculation is concerned with all load cases beginning with the inner top cover plate weld, identified as Load FL-6 in Table 1.

The loading conditions of interest in this evaluation are internal and external pressure and inertial loads due to handling, transfer, seismic, and accidental drop conditions.

As discussed in Section 4.1, secondary (thermal) loading is not considered.

Note that the discussions below, and the analyses performed in this calculation, are based on the conservative design values for internal pressure loading, rather than the actual calculated values of internal pressure. Table 2 summarizes the conservative design values as well as the actual calculated values.

Temperatures used for the material properties for each Service Level condition are listed in Table 3 and discussed further in the paragraphs below.

Service Level A The bounding Service Level A load combination for the 0SC top end cover plates and welds is load case TR-5 which combines the hot ambient condition with internal pressure and ig axial inertial loading. The other directions of inertial loading are not considered critical since their effects are not directly additive to the internal pressure loading, and furthermore they are bounded by the 75g side drop load discussed further below.

The lg axial load will cause the D50 payload weight (fuel, basket, holddown ring, shield plug) to bear against the ITCP. The total maximum payload weight is 75,811 lbs conservatively including the weights of the ITOP and OTCP [Ref. 5.2 Section 10.2]. The equivalent uniform pressure applied to the top-end components is therefore:

75,811 Pfuel,lg = r-22.0 psi

~x (66.25Sin) 2 Where the inner diameter of the DSC shell is 66.25 inches.

Therefore, the bounding Service Level A case is a uniform 10 psi internal pressure (for a Type 1 D30) plus an additional 22.0 psi acting on the shield plug in the outward axial direction of the DSC Shell.

Conservatively, this analysis considers the combined 10+22=32 psi load as a uniform internal pressure in the DSC Shell. This is very conservative since the fuel pressure load which is applied to the inner surface of the shield plug would in reality be distributed to the perimeter of the ITOP as a line load by the significant stiffness of the 7-inch thick shield plug. In other words, the approach used in this calculation maximizes the bending loads on the cover plates and therefore maximizes the loading on the closure welds.

Note that the cases with external pressure loading are discussed below.

A Calculation No. 11042-0205 Revision No. 1 AR EvA Calculation Page 18of77 Service Level B The bounding Service Level B load combination for the DSC top end cover plates and welds is the combination of the hot ambient condition with the off-normal internal pressure of 20 psi. All of the other Service Level B conditions, such as ram push/pull loads, do not affect the top end components. Therefore, the bounding Service Level B case is a uniform 20 psi internal pressure. Since the pressure loading is smaller (20 psi for SL B versus 32 psi for SL A as described above) and since the same limit load acceptance criterion is used for Service Levels A and B, this case is bounded by Service Level A.

Service Level C The bounding Service Level C load combination for the DSC top end cover plates and welds is HSM-8 which combines the hot ambient condition, normal internal pressure, and seismic loading. However, the seismic loads are bounded by the handling loads [Ref. 5.2 Section 7.8] discussed above for Service Level A. In addition, the acceptance criteria for Level C limit load analysis is greater than Service Levels A and B.

Therefore, all Service Level C conditions are bounded by the Service Level A case described above.

Note that the other Service Level C cases (such as LD-7 and UL-7) are for accident condition DSC ram push/pull loads. These loads do not affect the DSC top end components. Therefore they are not applicable to this analysis.

Note that cases with external pressure loading are discussed below.

A Calculation No. 11042-0205 Revision No. I AR EVA Calculation Page 19of77 Service Level D Three load combinations are found to be critical for Service Level D loading of the DSC top end components, namely:

accident level internal pressure

corner drop

side drop The first load combination is HSM-5 or HSM-6 which consist of 65 psi internal pressure due to HSM blocked vent thermal conditions. This load is not combined with any other load that affects the top-end components.

Therefore, the first bounding Service Level D load case considered in this analysis is 65 psi internal pressure. Note that in this condition the maximum DSC shell temperature is 611 0 F and 625 °F is conservatively used in this analysis (See Table 3).

The other Service Level D conditions consist of the drop events and accident-level seismic loading. The accident seismic loads are bounded by the handling loads [Ref. 5.2 Section 7.81 discussed above for Service Level A. The end-drop load is not a credible event [see footnote 12 to Table 1] but was used in the original calculation [Ref. 5.2] to bound the corner drop event. However, that analysis produced negligible load in the top cover plate welds due to the idealized boundary conditions. As a result of an RAI by the NRC, the corner drop is considered using an alternate idealization that maximizes the load in the top cover plate welds. In this case, the 25-g corner drop load has an axial component that may be considered to load the top end cover plates with the inertia of the fuel, shield plug, hold-down ring, ITOP and OTOP. This case is evaluated in Section 6.4.

The 75g side drop load TR-1 0 is considered a critical load case and is evaluated in detail. Note that this load case represents 75x more load than the Service Level A 1lg inertial loads. As discussed in Section 4.1, the Service Level D acceptance criterion is only 2.1 times less stringent than the Service Level A/B criterion.

Therefore, evaluation of the 75g side drop case using the Service Level 0 criterion is bounding of the Service Level A transverse inertial loading. (Also, as discussed in Section 4.3, the boundary conditions used for the 75g side drop analysis are conservative and representative of the boundary conditions encountered for the Service Level A inertial loads and seismic loading.) The 75g side drop case also includes the off-normal internal pressure of 20 psi, as shown in Table 1.

Note that the side drop event TR-1 0 occurs during transfer operations which result in a maximum DSC shell temperature of 500 °F as shown in Table 3. The higher Service Level D temperature of 625 °F discussed above occurs only during DSC storage in the HSM, and therefore is not combined with the side drop loading.

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 20 of 77 External Pressure Loadinci External pressure is present on the DSC in load cases 00-2 (vacuum drying, Service Level A) and HSM-9/10 (flood load, Service Level C). (The load cases with hydrostatic external pressure are due to the cask annulus being filled with water while the cask and DSC are in the vertical position. In this case the pressure load varies from zero at the top of the DSC to a maximum value at the bottom of the cask. Since the external pressure near the cover plates is essentially zero, these cases are not critical and are not considered further in this calculation.)

In load case 00-2, the external pressure is 14.7 psi (full vacuum). This pressure is bounded by the Service Level B off-normal pressure (20 psi) and therefore primary stresses in the cover plates and welds are bounded by the internal pressure load cases. Stability concerns of the DSC shell are not affected by the presence of weld flaws since they are at the end of the cask, remote from the locations at which buckling would occur. Therefore external pressure load case 00-2 is not critical and is not considered further in this analysis.

In load case HSM-9/10, the flood load is due to a 50-foot static head of water, which is equivalent to 22 psi external pressure [Ref. 5.2 Section 7.9]. This pressure is bounded by the 32 psi internal pressure considered for Service Level A discussed above. Therefore the flood load case HSM-9/10 is bounded by the other internal pressure load cases.

Summary The bounding load cases considered for the limit load collapse analyses are therefore:

(See Table 3 for temperature references)

Service Level A/B: 32 psi Uniform Internal Pressure, Properties at 500 0F Service Level D-1: 65 psi Uniform Internal Pressure, Properties at 625 °F Service Level 0-2: 75g Side Drop Acceleration plus 20 psi Uniform Internal Pressure, Properties at 500°F.

A Calculation No. 11042-0205 Revision No. 1 AR EVA- Calculation Page 21of 77 4.3 FEA Model Details Several finite element models of the top half of the 61 BTH DSC are constructed in ANSYS based on the Reference 5.3, 5.4, 5.5 drawings. The models fall into two basic categories: axisymmetric (20) and half-symmetric (3D).

The axisymmetric models use ANSYS plane element type PLANE182, a 4-node axisymmetric plane element with non-linear capabilities. Each node has 2 degrees of freedom (translation in the X (radial) and Y (axial) directions, and rotation about the circumferential direction). The default element options are used in the analysis. Sensitivity studies were performed to ensure that there were no adverse effects on the results due to the potential shear locking of the elements. (Sensitivity runs used KEYOPTION 1=3 to invoke the simplified enhanced strain formulation to relieve shear locking.) Additional discussion of the sensitivity analyses is provided in Section 6.0.

Contact between the ITOP and OTCP is simulated using nodal coupling in the Y (axial) direction. (See Section 6.1.2 for a sensitivity study using contact elements at this interface.)

No contact is defined between the opposing faces of the weld flaws. In other words, whereas compressive loading normal to the plane of the flaw may in reality be transmitted via compression through the crack face surfaces, this load path is ignored. This is conservative, and considered necessary since it is difficult (or impossible) to deduce from the PAUT data what separation may exist between the two faces of the flaws.

Also, no contact is considered between the DSC shell inner diameter and the ITCP and OTCP outer diameters. As seen in Figure 4, the fabricated dimensions of the lids and shell result in small radial gaps between the outer diameter of the lids and the inner surface of the shell. During the welding process, these gaps close, but since a small remaining gap cannot be ruled out, this analysis conservatively assumes that the as-fabricated gap exists, as shown in Figure 4. Even ifthe lids deflect in the analysis such that the gaps would close, the resulting contact/compressive load path is conservatively neglected. This is conservative since it forces all loads in the lid to travel through the weld, rather than through compression between the lids and shell.

Figure 11 and Figure 12 show images of the axisymmetric model. Loading and boundary conditions are discussed in the following sections.

A Calculation No. 11042-0205 Revision No. I A RE vA Calculation Page 22 of77 The 3D, half-symmetric model uses ANSYS solid element type SOLID185, an 8-node brick (or 6-node prism) element with non-linear capabilities. Each node has 3 degrees of freedom (translation in the X, Y, and Z directions). The default element options are used in the analysis. Sensitivity studies were performed to ensure that the mesh was adequate. Additional discussion of the sensitivity analyses is provided in Section 6.0.

Contact in the half-symmetry model is defined using ANSYS element types CONT1 73 and TARGE1 70.

Contact is defined between the following interfaces:

OTCPto ITCP

ITCP to Shield Plug

Shield Plug outer diameter to DSC Shell

Shield Plug bottom surface to Support Ring

Support Ring to DSC Shell The default contact parameters are used, although the contact stiffness is reduced in some cases to aid in convergence. Due to the large contact areas and since the contact areas are generally remote from the critical stress regions, the contact stiffness is not considered a critical parameter. The default contact parameters include: [Reference 5.6]

Penetration tolerance factor: Default value - 0.1. This parameter controls the acceptable level of penetration of the contact node into the target surface, based on the depth of the element underlying the target element.

Pinball region scale factor: Default Value = 1.0. This parameter controls the extents of the region around each contact node that is checked for contact with target segments. The default volume is a sphere of radius 4*depth of the underlying element.

KeyOption 2: Contact algorithm: Default = Augmented Lagrangian. The contact method is an iterative penalty method where the contact pressure is augmented during the equilibrium iterations so that the final penetration is within the acceptable tolerance.

KeyOption 4: Location of contact detection point: Default = On Gauss Point. Other options include using the nodal points, normal to either the contact surface or the target surface. The default option is suggested for general cases.

Other features and controls of the CONTA1 73 elements are related to advanced features (bonded contact, cohesion, etc.) and initial penetration and gap controls which are not utilized in this analysis.

Figure 19 through Figure 21 show images of the half-symmetry model. Loading and boundary conditions are discussed in the following sections.

Table 6 shows a summary of the ANSYS models and analyses which are performed. Further details on the various ANSYS models are provided below.

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 23of77 4.3.1 Axisymmetric Case #1 The first case considered is a combination of OTCP Flaw Set #1 and the ITCP bounding flaw set discussed in Sections 3.2.1.1 and 3.2.2, respectively. The mesh and flaw details for this case, called Axisymmetric Case #1, are shown in Figure 13 and Figure 14.

The mesh shown in these figures was created based on a basic goal of having at least 4 elements across the thickness of the net sections of the weld, as reduced by the flaws. In order to investigate the effects of mesh density, a refined mesh was created for this case, as shown in Figure 15. Analyses later showed that the collapse pressure is dictated by plastic hinge failure of the cover plates at the centerline of the cask.

Since the sensitivity model shown in Figure 15 only refined the weld region an additional model was created as shown in Figure 16 to ensure a sufficient mesh in the lid interior region.

This model, and all of the other axisymmetric models discussed below, are used for analysis of uniform internal pressure loading. The model is constrained in the radial direction at the axis of symmetry and in the axial direction at the bottom cut of the DSC shell near the mid-length of the cask (remote from the top end components of interest.) The pressure loading is applied to the internal pressure boundary (bottom surface of ITCP, surface of ITCP weld to Shell, and Shell inner surface). (See Section 6.1.2 for a sensitivity analysis where internal pressure is included on the ITOP weld root flaw internal surfaces.)

4.3.2 Axisymmetric Case #2 The second case considered is a combination of OTCP Flaw Set #2 and the ITOP bounding flaw set discussed in Sections 3.2.1.2 and 3.2.2, respectively. The mesh and flaw details for this case, called Axisymmetric Case #2, are shown in Figure 17 and Figure 18. Based on the results of the Axisymmetric Case #1 (See Section 6.1.2), the initial mesh level described above for Case #1 is sufficient. However, since the run times remained reasonable, only the refined mesh model (weld and lid interior regions) is used for Case #2.

4.3.3 Axisymmetric Case #0 In order to study the effect of the flaws, a 3 rd case is considered in which the flaws are removed and the as-designed collapse load is determined. Only the refined mesh model (weld and lid interior regions) is considered. The mesh is identical to Figure 16 but the coincident nodes along the crack faces are merged.

A Calculation No. 11042-0205 Revision No. 1 AR REVA Calculation Page 24 of 77 4.3.4 Half-Symmetry (3D) Case #1 The 3D model is based on the Axisymmetric Case #1. (Analysis results showed that there was negligible difference in the results from Axisymmetric Case #1 and Case #2. The total projected cross-sectional area of the flaws in Case #1 is greater than Case #2. Therefore, Case #1 is considered critical for the side drop loading).

The same flaw pattern is modeled, but the initial mesh is slightly less refined in order to obtain reasonable run times. Mesh sensitivity studies are described below. The half-symmetry model is used for internal pressure loading (as a benchmark case to study the effects of mesh refinement) and also for side-drop loading.

The shield plug support ring is connected to the DSC shell at the two corners using nodal DOE couples to represent the fillet welds used to join the two parts.

In order to improve the numerical stability of the ANSYS model, soft springs (COMBIN14) elements are used to connect the shield plug to the support ring. The springs have a stiffness of 1 lb/in. The low stiffness combined with the very small relative deflections between these parts results in negligible internal force in the springs. The forces in the springs at the final converged solution are reviewed to confirm that the spring forces are small.

In all load cases, symmetry conditions are applied to the cut face of the model. Axial constraints are applied at the bottom cut of the DSC shell near the mid-length of the cask (remote from the top end components of interest.) For the internal pressure load case, the model was further reduced to a 90-degree model and symmetry constraints were placed on both cut faces of the model.

The purpose of this calculation is to evaluate the effects of the closure weld flaws and qualify the welds and any other components affected by the welds. All other aspects of the 0SC (such as the shell remote from the welds) are not in the scope of this calculation. The modeling approach (loads and boundary conditions) for the side drop event are considered in light of this purpose and are described in the following paragraphs.

For the side drop cases, the OD of the canister shell is constrained in the vertical (drop) direction for a small sector (approximately 1.5,' inches or 2.8 degrees) of assumed contact. In reality the DSC is supported inside the Transfer Cask (TC) during this event. Therefore the true boundary condition would either be a line of contact along a TC rail (which is 3" wide) or a line of contact at areas remote from the rails. As deformations increase, the area of contact would also increase. As discussed below in Section 4.4, deflections are over-estimated in a limit load analysis. Therefore, the area of contact with the TC rail or inner surface is assumed to be constant. This conservatively neglects the increase in contact area that would occur during the drop deformations. Additionally, this boundary condition is representative of the DSC storage condition inside the HSM, where the DSC rests on the 3-inch wide steel rails.

As discussed in the Reference 5.2 calculation, the DSC payload (basket and fuel) are located approximately 21.5 inches away from the ITCP and are therefore considered to have no effect on the DSC lid components.

The effect of the basket and fuel loading on the DSC shell is considered in the basket design-basis calculation for side-drop loading. The basket hold-down ring is a grid-type structure that does not represent significant weight and is of sufficient strength and stiffness to be self-supporting during the side drop and not significantly affect the DSC shell and adjacent regions. Therefore, as in the Reference 5.2 calculation, the DSC payload is not considered as affecting the top-end components and the weight is applied as a pressure along a strip of elements at the impact region, beginning approximately 23" below the ITCP. Since the loads

A Calculation No. 11042-0205 Revision No. I AR EVA Calculation Page 25of77 are essentially applied directly over the supported (impact) region of the OSO shell, they have no appreciable effect on the shell deformations.

Images of the Half-Symmetry model are shown in Figure 19 to Figure 21.

In order to study the adequacy of the mesh for the half-symmetry model, an internal pressure load case was performed and compared to the results of the axisymmetric case refined mesh. This study confirms the adequacy of the mesh in the cross-section of the 3D model. In order to evaluate the mesh in the circumferential direction, a model was created with a refined mesh in the regions of the model showing large plastic strains (the impact region) and locations where tensile stress is expected in the weld (at the 90-degree location where the lid resists ovalization of the DSC shell). This model is shown Figure 22.

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 26 of 77 4.3.5 Half-Symmetry (3D) Case #0 in order to study the effect of the flaws, an additional case is considered in which the flaws are removed from the model and the as-designed side drop limit load capacity is determined.

4.4 Limit Load Solution Details As discussed in Section 4.1, this calculation is based on predicting the lower-bound collapse loads of the DSC based on limit load analysis. All materials are modeled as elastic-perfectly plastic 1 , with yield stress values based on the limit load analysis requirements of the ASME code. Table 3 lists the temperatures used for each load case, and the values of the material properties are shown in Table 4 and Table 5.

The prescribed loads are applied to the model, and then are increased linearly until the solution fails to converge.

The analyses use small deflection theory (NLGEOM,OFF). This is conservative since deflections are unrealistically high in a limit load analysis due to the lower-bound non-strain-hardening material properties that are used. If large deflections were to be considered, the beneficial effects of OTCP and ITCP membrane action and of increased contact areas would be over-estimated, resulting in non-conservative effects. This was verified with a sensitivity study using NLGEOM,ON, which resulted in much higher collapse pressures. This confirmed that using NLGEOM,OFF is appropriate, and conservative.

I "Elastic-perfectly plastic is standard mechanics of materials term that describes an idealized material that behaves in a linear-elastic manner up to the yield point, and thereafter is perfectly-plastic, i.e. non-strain hardening.

A Calculation No. 11042-0205 Revision No. I AR EVA Calculation Page 27 of 77

5.0 REFERENCES

5.1. AREVA Document No. 180-9236022-000. NDE Services Final Report. "Monticello, DSC-16, Phased Array UT Examination Results of the Inner and Outer Top Cover Lid Welds."

Revision 0.

5.2. AREVA (Transnuclear) Calculation No. NUH61BTH-0200 Revision 0. "NUHOMS-61BTH Type I Dry Shielded Canister Shell Assembly Structural Analysis."

5.3. AREVA (Transnuclear) Drawing No. NUH61BTH-3000 Revision 7. "NUHOMS 61BTH Type 1 DSC Main Assembly."

5.4. AREVA (Transnuclear) Drawing No. NUH61BTH-3001 Revision 4. "NUHOMS 61BTH Type 1 DSC Shell Assembly."

5.5. AREVA (Transnuclear) Drawing No. NUH61BTH-4008 Revision 1. "NUHOMS 61BTH Type 1

& 2 Transportable Canister for BWR Fuel Field Welding."

5.6. ANSYS Version 14.0. ANSYS Inc. (Including the ANSYS Mechanical APDL Documentation).

5.7. ASME Boiler and Pressure Vessel Code,Section III Subsection NB. 1998 Edition with Addenda through 2000.

5.8. AREVA (Transnuclear) Document Number NUH-003 Revision 13. "Updated Final Safety Analysis Report for the Standardized NUHOMS Horizontal Modular Storage System for Irradiated Nuclear Fuel."

5.9. ASME Boiler and Pressure Vessel Code,Section III Appendices. 1998 Edition with Addenda through 2000.

5.10. ASME Boiler ad Pressure Vessel Code, Section Xl. Rules for Inservice Inspection of Nuclear Power Plant Components. 1998 Edition with Addenda through 2000.

5.11. AREVA (Transnuclear) Document No. NUH61BTH1-0101 Revision 0. "Design Criteria Specification for the NUHOMS-61 BTH Transportable Storage Canister."

5.12. AREVA Calculation No. 11042-0204 Revision 3. "Allowable Flaw Size Evaluation in the Inner Top Cover Plate Closure Weld for DSC #16" 5.13. Chattopadhyay, Somnath. "Pressure Vessels Design and Practice." CRC Press. 2004.

5.14. TriVis Incorporated Welding Procedure Specification No. SS-8-M-TN Revision 10.

5.15. ASME Boiler and Pressure Vessel Code,Section II, Part C. "Specifications for Welding Rods, Electrodes, and Filler Metals." 1998 Edition with Addenda through 2000.

5.16. ASME Boiler and Pressure Vessel Code,Section II, Part D. "Properties." 1998 Edition with Addenda through 2000.

5.17. AREVA (Transnuclear) Calculation No. NUH61BTH-0253 Revision 0. "NUHOMS 61BTH Type 1 DSC Shell Assembly Outer Top Cover Plate Critical Flaw Size of Weld."

A Calculation No. 11042-0205 Revision No. 1 AREVA Calculation Page 28 of 77 6.0 ANALYSIS Table 6 shows a summary of the results of all of the analyses performed for this calculation and includes a comparison of the results with the acceptance criteria. Each case is discussed in more detail below.

6.1 Axisymmetric Analyses for Internal Pressure 6.1.1 Axisymmetric Case #1 - Initial Mesh Model Two analyses are performed with the Axisyrnmetric Case #1 initial-mesh model described in Section 4.3.1:

one case using the Service Level A/B material properties and one case using the Service Level 0 material properties. The collapse pressures were determined to be 95.9 psi for Service Level A/B and 136.6 psi for Service Level D. Figure 23 shows various plots of the plastic strain in the initial-mesh model for Service Level A/B at various locations and levels of loading. These strain plots are also representative of the behavtior of the Service Level D analysis. Figure 24 shows the deflection history at the center of the lid, and indicates the expected plastic instability that occurs as the limit load is approached.

Since the initial mesh contains several element divisions at each critical cross-section, it is not expected that element shear locking (due to the default fully-integrated elements) will be significant. To confirm this, a test case was done using the Service Level A/B model but with the Simplified Enhanced Strain element formulation (KEYOP 1=3). The collapse pressure was found to be 96.1 psi, which is essentially identical to the initial results.

6.1.2 Axisymmetric Case #1 - Refined Mesh Models Additional analyses are performed using the Service Level A/B material properties with the refined mesh models described in Section 4.3.1. Figure 25 and Figure 26 show the plastic strain results for the refined mesh at the weld region and the refined mesh at the weld and lid interior regions, respectively. The collapse pressures were found to be 94.8 psi and 93.8 psi, respectively, for these models. The OTCP deflection.

histories are shown in Figure 27.

Figure 28 shows a comparison of the maximum displacement history curves for the various Axisymmetric Case #1 models. As seen in the figure, the results match very well. The results of the refined mesh models deviate at most (95.9-93.8)/93.8 = 2.2% from the initial mesh results. This is very close agreement particularly due to the non-linear nature of the analysis. Therefore, the initial mesh is considered sufficient.

However since the analysis run times for the axisymmetric cases are reasonable even for the refined mesh model, the remaining axisymmetric cases use a refined mesh.

The Axisymmetric Case #1 with refined weld and lids for Service Level D criteria reported a collapse pressure of 132.6 psi.

Note that the nodal coupling in the axial direction between the ITCP and OTCP is a valid method to model the contact between the plates since the internal pressure loading ensures that the ITCP lid will bear against the TOTP, and since the nodes that are coupled remain coincident throughout the analysis, with only very minor differences in radial position occurring at the later load steps. In order to confirm the behavior of the nodal coupling, the Axisymmetric Case #1 model with refined welds and lids was modified to include contact between the ITCP and OTCP. The model replaces the nodal coupling with CONTAI71 and TARGE169 elements, using the default element parameters. Figure 29 shows a comparison between the model using

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 29of77 DOF couples and the model using contact elements. As seen in the figure, the results are very similar, with the DOF-couple-model showing slightly more conservative results. Therefore, the nodal coupling is acceptable and is used in all other axisymmetric models.

Note that in all of the FEA models, the internal pressure loading was not applied to the faces of the ITCP weld root flaw that is exposed to the internal region of the cask. Pressure loading on this crack face is negligible since the flaw is only 0.09" high, and in reality the ITOP flaws are generally very short (i.e. not full-circumferential flaws). In order to support this conclusion, a sensitivity analysis is performed where the pressure loading is applied to the ITCP weld root crack faces. The results, shown in Figure 30, confirm that pressure loading on the faces of this flaw are negligible.

. Calculation No. 11042-0205 Revision No.

AR EVA Calculation Page 30of77 6.1.3 Axisymmetric Case #2 Two analyses are performed with the Axisymmetric Case #2 refined-mesh model described in Section 4.3.2:

one case using the Service Level A/B material properties and one case using the Service Level 0 material properties. The collapse pressures were determined to be 93.7 psi for Service Level A/B and 132.9 psi for Service Level D. Figure 31 shows various plots of the plastic strain for Service Levei A/B at various locations and levels of loading. These strain plots are also representative of the behavior of the Service Level D analysis.

6.1.4 Axisymmetric Case #0 One analysis is performed with the Axisymmetric Case #0 refined-mesh model described in Section 4.3.3 using the Service Level A/B material properties. The collapse pressures were determined to be 94.5 psi for Service Level A/B. Figure 32 shows various plots of the plastic strain at various locations and levels of loading.

Figure 33 shows a comparison of the maximum center-of-lid displacement history for all three axisymmetric cases. As seen in the figure, there is essential no difference between Axisymmetric Case #0, Case #1 and Case #2. The Case #1 and Case #2 analyses show slightly larger deflections early in the analysis due to the slightly reduced rotational fixity of the welds. However, the final collapse pressure are within (94.5-93.7)193.7=0.9% of each other, and the failure mode (plastic collapse at the center of the lids) is the same.

This supports a supposition that the observed flaws have negligible impact on the governing failure mode of the top end closure plates and welds.

A Calculation No. 11042-0205

. Revision No. 1 AR EVA Calculation Page 31lof 77 6.2 Half Symmetry Analyses for Internal Pressure (Benchmark Cases)

The model described in Section 4.3.4 is Used for an internal pressure collapse analysis in order to benchmark the model against the axisymmetric cases. The collapse pressure was calculated to be approximately 97 psi. (The run was terminated at 95 psi and the final collapse pressure was estimated to avoid excessive computer run time). Figure 34 shows various plots of the plastic strain at various locations and levels of loading. A comparison of the half-symmetry case to the refined-mesh axisymmetric case is shown in Figure 35. As seen in the figure, the half-symmetry case closely matches the behavior of the refined mesh axisymmetric model although the results indicate a slightly greater collapse pressure.

Therefore, the half-symmetry model is considered sufficiently accurate for this analysis. As shown by the results, and as discussed in Section 7.0, there is significant safety margin available such that further mesh refinement of the half-symmetry model is not warranted. However, the effects of circumferential mesh density for the half-symmetry model can be seen in Section 6.3.1.

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. Revision No. 1 AR REVA- Calculation Page 32 of 77 6.3 Half Symmetry Analyses for Side Drop Loading 6.3.1 Half-Symmetry Case #1 The model described in Section 4.3.4 is used to perform two side-drop limit load analysis. One case includes side-drop acceleration loading only, while the second case includes the DSC off-normal internal pressure of 20 psi. For this later case, the 20 psi internal pressure is applied simultaneously with a 75g acceleration, and then both the pressure and the acceleration are increased linearly until the collapse g-load is obtained. (For example, for collapse occurring at 181g, the internal pressure at collapse is 20*181/75 =

48.3 psi.)

Note that the side drop loading is combined with the design-basis off-normal internal pressure of 20 psi, as opposed to the internal pressure value of 32 psi used for the SL A/B cases which was the sum of the 10 psi normal pressure and an additional 22 psi to account for inertial handling/seismic loads. See Section 4.2 The collapse g-load for side-drop-only loading was found to be approximately 181g. The collapse g-load when internal pressure loading was included was found to be greater than 181g. This later run terminated at 181g, but based on the collapse behavior (see Figure 41) it is expected that smaller time steps would allow the solution to continue to larger loads.

Various images of the stress and strain in the side drop analyses are shown in Figure 36 to Figure 38.

The Half-Symmetry Case #1 model with refined mesh in the circumferential direction was used to evaluate the side drop load case (without internal pressure). This analysis was performed up until a load of 185 g's, at which time the analysis was terminated manually to avoid large file sizes and excessive run time. As seen in Figure 41, this model showed a greater resistance to the side-drop loading, and would eventually result in collapse g-loads in excess of 185 g ifsmaller timesteps and longer run times were provided. Images of the stress and strain from this analysis are shown in Figure 39. This analysis confirms that the mesh used in the.

other half-symmetry cases is adequate, and conservative.

A Calculation No. 11042-0205 Revision No. I AR EVA Calculation Page 33 of 77 6.3.2 Half-Symmetry Case #0 One side drop analysis is performed with the Half-Symmetry Case #0 model (no flaws) described in Section 4.3.5. Based on the results discussed above, only the case without internai pressure loading was considered. This analysis resulted in a collapse load of 189g. Stress and strain plots from this analysis are shown in Figure 40. As shown in Figure 41, the collapse behavior was nearly identical to the case with weld flaws, indicating that the flaws had negligible effect on the results.

6.4 Evaluation of the 25g Corner Drop Reference 5.2 Section 10.2 evaluated the OTCP weld to resist a 25g inertial load on the entire DSC contents and neglecting the strength of the ITOP weld. Furthermore, a conservative stress was assumed in the weld due to internal pressure. The Reference 5.2 calculation is revised below to account for the strength of both welds and include a reduction in the weld thickness due to the observed flaws. The total weld thickness is taken as the combined weld throats from the ITCP and OTCP minus the height of the flaws present in the welds. (See Reference 5.2 Section 10.2 for the basis of the following values and calculations.)

WTOT = 75,8111bs (total weight of fuel + basket + lids and shield plug)

Wp= 68,943 lbs (load due to pressure)

WTOT25g = 25 x 75,811 + 68,943 =1,964,218 lbs Wror2sQ __ 1,964,218 _ ,3L (ent fwl i 0.3" W-g"" wl 208.131 ' tm lnghofwldi 3 1 tweld = - + - (0.23 + 0.11) = 0.3475 in (* See Note)

T 2=5 ,4375 __27,157 psi (weld shear stress due to 25g corner drop) 2g tweld 037 T2o Ps.= 4,120 psi (weld stress due to 20 psi internalpressure)

Tror L25gq T +[ T2Opsi 27,157 + 4,120 =31,277 psi TAllow = 32,400 psi T

TOT _31,277

=0.97*<1

- (0K)

TAllow 32,400

Note: the reduction of the weld to account for the flaws is based on the maximum flaw heights in any one plane through each of the welds. This is taken as 0.23" for the OTCP weld and 0.11" for the ITCP weld.)

Therefore, the top end closure welds, with the observed flaws, are OK for the Service Level 0 corner drop event.

A Calculation No. 11042-0205 Revision No. 1 AR--- EVA Calculation Page 34of77 7.0 DISCUSSION AND CONCLUSIONS The lower bound collapse pressure for Service Level A/B criteria was found to be 93.7 psi which is 1.95 times the required pressure of I1.5x32=48 psi (Where 1.5 is the code-required safety factor on the 32 psi pressure loading - see Section 4.2).

The lower bound collapse pressure for Service Level D criteria was found to be 132.6 psi which is 1.84 times the required pressure of 1.1 lx65=72.15 psi (Where 1.11 is the code-required safety factor on the 65 psi pressure loading - see Section 4.2).

As noted in Section 6.1.4 and as shown in Figure 33, there is essentially no difference in the collapse pressure and extremely little difference in the overall collapse behavior and deflection of the DSC subjected to internal pressure loading with and without flaws in the weld. Even with the conservative representation of the weld flaws, there remains sufficient shear strength in the weld such that failure does not occur until plastic collapse of the ITCP and OTCP at the centerline of the cask.

The lower bound collapse acceleration for side drop (Service Level D) loading was found to be 181g which is 2.2 times the required load of 1.11x75=83.25g.

As noted in Section 6.3.2 and as shown in Figure 41, there is essentially no difference in the collapse load and behavior between the as-designed DSC and the DSC with closure weld flaws.

The Reference 5.12 and 5.17 calculations document the ITCP and OTCP closure weld critical flaw sizes, respectively, based on the maximum radial stresses in the welds. The guidance and safety factors of Reference 5.10 are used in the critical flaw size analysis. The critical flaw sizes are determined to be 0.19 and 0.29 inches for surface and subsurface flaws, respectively, in the OTCP weld and 0.15 inches for surface and subsurface flaws in the ITCP weld. The largest single OTCP flaw size documented in Reference 5.1 is 0.14 inches. As discussed in Section 3.2 a very conservative maximum combined flaw height of 0.195 inches is assumed in this analysis. The largest single ITCP flaw size documented in Reference 5.1 is 0.11 inches. Therefore, the observed flaws actually are smaller than the critical flaw size limits and therefore it is not surprising that the flaws are shown to have little effect on the capacity of the structure. This analysis shows that the quantity and close proximity of some of the flaws also has no significant adverse effects on the structural capacity of the DSC.

Therefore it is concluded that Monticello DSC-16, remains in compliance with the ASME Section III Subsection NB [Ref. 5.7] stress limits with the presence of the ITCP and OTCP closure weld flaws as documented in Reference 5.1.

A Revision No.

Calculation No. _

11042-0205 AR EVA Calculation Page 35of77 8.0 LISTING OF COMPUTER FILES Analyses performed on Computer HEA-0213A using ANSYS Version 14.0 [Ref. 5.6].

File Date & Time listing is as displayed by the Windows 7 Operating System - Differences may occur due local time zone and daylight savings settings.

Analysis Case File Name Date & Time Axisymmetric 1 618THWeldFlaw 1FAX_2_DETACH.db 4/7/2015 10:45 AM Initial Mesh 618THWeldFlaw iFAX_2_DETACH.rst 4/7/2015 10:45 AM Internal Pressure 618THWeldFlaw iF AX 2 DETACH.mntr 4/7/2015 10:45 AM SL A/B SOLUTION AXISYMM_ IP LimitLoad.INP 4/7/2015 10:20 AM Axisymmetric 1 618THWeldFlaw 1FAX_2_DETACH.db 4/7/215 11:59 AM Refined Weld Mesh 61BTHWeldFlaw iF AX_2_DETACH.rst 4/7/215 11:58 AM Internal Pressure 618TH_WeldFlaw 1F AX_2_DETACH.mntr 4/7/215 11:59 AM SL A/B SOLUTION AXISYMM_ IPLimitLoad.INP 4/7/2015 11:55 AM Axisymmetric 1 61BTHWeldFlaw 1FAX_2_DETACH.db 4/21/2015 9:04 AM Refined Weld and Lid Mesh 61BTH_WeldFlaw iFAX_2_DETACH.rst 4/21/2015 9:03 AM Internal Pressure 61BTHWeldFlaw 1F AX_2_DETACH.mntr 4/21/2015 9:04 AM SLABSOLUTION AXISYMM IPLimitLoad.INP 4/7/2015 11:55 AM Axisymmetric 1 618THWeldFlaw 1FAX_2_DETACH.db 4/20/2015 10:43 AM Initial Mesh 61BTHWeldFlaw 1F AX 2 DETACH.rst 4/20/2015 11:09 AM Internal Pressure 618TH_WeldFlaw 1F AX_2_DETACH.mntr 4/20/2015 11:09 AM SL DSOLUTIONAXISYMM IPLimitLoadSLD.INP 4/7/2015 11:20 AM Axisymmetric 1 618THWeldFlaw iFAX_2_DETACH.db 4/30/2015 8:12 AM Refined Weld and Lid Mesh 61BTHWeldFlaw 1FAX_2_DETACH.rst 4/30/2015 8:12 AM Internal Pressure 618TH_WeldFlaw 1F AX_2_DETACH.mntr 4/30/2015 8:12 AM SL D SOLUTION_AXISYMM_ IPLimitLoad_SLD.INP 4/7/2015 12:02 PM Axisymmetric 2 61BTH_WeldFlaw_2GAX_2.db 4/21/2015 3:06 PM Refined Weld and Lid Mesh 61BTHWeldFlaw 2GAX_2.rst 4/21/2015 2:58 PM Internal Pressure 61BTHWeldFlaw 2G AX 2.mntr 4/21/2015 3:06 PM SL A/B SOLUTION_AXISYMM_IP_LimitLoad.INP 4/7/2015 11:55 AM Aimmri261BTHWeldFlaw 2G AX_2.db 4/21/2015 3:10 PM Refined Weld and Lid Mesh 618THWeldFlaw 2G AX_2.rst 4/21/2015 3:10 PM Internal Pressure 61BTHWeldFlaw 2GAX_2.mntr 4/21/2015 3:10 PM SL D SOLUTION_AXISYMM_ PLimitLoad_SLD.INP P 4/7/2015 12:02 PM xsy etiO618TH WeldFlaw IFAX_2_DETACH.db 4/21/2015 10:39AM Refined Weld and Lid Mesh 61BTHWeldFlaw IF AX_2_DETACH.rst 4/21/2015 10:31 AM Internal Pressure 618TH_WeldFlaw IF AX_2_DETACH.mntr 4/21/2015 10:39 AM SL A/8 SOLUTIONAXISYMM_ IPLimitLoad.INP 4/15/2015 11:07 AM Axisymmetric 1 618THWeldFlaw IFAX_2_DETACH.db 4/17/2015 5:40 PM Initial Mesh with Keyoption 1=3 618THWeldFlaw IFAX_2_DETACH.rst 4/17/2015 5:40 PM Internal Pressure 618TH_WeldFlaw IF AX_2_DETACH.mntr 4/17/2015 5:40 PM SL A/B SOLUTION_AXISYMM_ IPLimitLoad.INP 4/16/2015 12:27 PM

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 36of77 Analysis Case File Name Date & Time Axisymmetric 1 61BTH_WeIdFlaw IF AX_2 DETACH.db 5/19/2015 8:45 AM Refined Weld and Lid Mesh 61BTHWeldFlaw IF AX 2 DETACH.rst 5/19/2015 8:02 AM Internal Pressure, SL A/B ITCP/OTCP couples replaced with 61BTH_WeldFlaw 1F AX_2_DETACH.mntr 5/19/2015 8:45 AM Contact SOLUTIONAXISYMMIPLimitLoad.INP 5/18/2015 5:03 PM Axisymmetric 1 61BTH_WeldFlaw 1FAX 2_DETACH.db 5/18/2015 2:42 PM Refined Weld and Lid Mesh 61BTH_WeldFlaw iF AX 2 DETACH.rst 5/18/2015 1:37 PM Internal Pressure, SL A/B With Pressure on ITCP Weld Root 61BTH_WeldFlaw 1F AX 2 DETACH.mntr 5/18/2015 2:42 PM Flaw Surfaces SOLUTION_AXISYMM IP LimitLoad.INP 5/18/2015 1:25 PM HlSymty161BTHWeldFlaw IGC.db 4/29/2015 2:10 PM Initial Mesh 61BTHWeldFlaw 1GC.rst 4/29/2015 4:52 PM Internal Pressure 61BTHWeldFlawI GC.mntr 4/29/2015 4:52 PM SL A/B SOLUTION HALFSYM LimitLoad.INP 4/29/2015 2:10 PM Half Symmetry 1 61BTHWeldFlawI GC.db 4/30/2015 8:20 AM Initial Mesh 61BTH_WeldFlawI GC.rst 4/30/2015 3:35 PM Side Drop 61BTHWeldFlaw 1GC.mntr 4/30/2015 3:35 PM SL D SOLUTIONHALFSYM_SD.INP 4/30/2015 8:21 AM HlSymty16IBTH WeldFlaw 1GC.db 5/1/2015 6:58 PM Initial Mesh 61BTHWeldFlaw 1GC.rst 5/1/2015 4:29 PM Side Drop + Internal Pressure 61BTH_WeldFlaw_1GC.mntr 5/1/2015 4:13 PM SL D SOLUTIONHALFSYMSD.INP 4/30/2015 10:26 PM Half Symmetry 1 61BTH_WeldFlaw_ 1GDRefined.db 5/6/2015 1:54 PM Refined Circumferential Mesh 61BTHWeldFlaw 1GD Refined.rst 5/6/2015 11:48 AM Side Drop 61BTH_WeldFlaw lGDRefined.mntr 5/6/2015 11:47 AM SL D SOLUTION HALFSYMSD.INP 5/5/2015 9:01 PM HlSymty061BTH WeldFlaw 1GC.db 5/2/2015 6:53 AM Initial Mesh 61BTHWeldFlaw_ 1GC.rst 5/2/2015 6:53 AM Side Drop 61BTHWeldFlaw_l1GC.mntr 5/2/2015 3:37 AM SL D SOLUTION_HALFSYM_SD.IN P 4/30/2015 8:21 AM

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 37 of 77 9.0 TABLES AND FIGURES Table I - Summary of Design Basis Load Combinations for the 61 BTH 030 [Ref. 5.8]

Load Case Horizontal DW Vertical DW Internal E~xternal Thermal lifting Other Servce DSC Fuel DSC Fuel Pressurec' Pressure Condition Loads Loads Level Non-Operational Lead Cases NO-I Fab. Leak Testng . . .. ..- 14.7 psig 70"$ - 1I5il dpxal Test NO-2 Fab. eak Testinz . . . .- 15/2_3 p~i 5W) _ 70$ - 55l-p axial Test NO-3 DSC Uprigb-ing x . .. ...- 70?F x - A NO-4 DSC VerticalLift - - s - - - 70?* xv - A Fuel Loading Load Cases FL-I DSC/Cask Filling - - Cask - - Hy'drostatic 120$F Cask iv x A FL-2 DS*CoCsk Filling - - Cask - Hydrostatic Hydrostatic 120$*Cask iv i A FL-3 DSC/Cask Xfer - - Cask - Hydrostatic Hydrostatic 120$F Cask - - A FL-4 Fuel Loading - - Cask iv Hydrostatic Hydrostatic 120$F Cask- - - A FL-i XIfer toDecon - - Cask iv Hydrostatic Hydrostatic 120$F Cask - - A FL-6 Iuner Cover plate Welding - - Cask iv Hydrostatic Hydrostatic 120$F Cask - -- A FL-7 Fuel Deck SeimaicLoading. - - Cask xv Hydrostatic Hydrostatic 120$F Cas~k. - Note 10 C DrainingfDn'ing Load Cases Hydrostatic DD-1 DIC Blowdona - - Cask iv + 10/15 psig Hydrostatic 120$ Cask - - A DD2VcsmDyn ak i m Hydrostatic 120$ Cask -A DD2VaumDqa - - Csk x 0 a + 14 psig -

DD-3 Helium Barkfill - - Cask xv l2psig Hydrostatic 120$FCask - - A DD-4 Final HeliwnBac"kfi1l - - Cask xv 3.5 prig H:ydrostatic 120$F Cad: - - A DD-i Outer Cover Plate Weld - - Cask iv 3.5 prig Hydrostatic 120$F Cas - - A Transfer Traier Loading

'"FL-IVe~eeal Xferto Trailer - - Cask xv 10/15 prig - O0FCas - -- A "TL-2 Vertical Xfer to Tnller - - Cask xv 10/li psig - 120$F Cask - - A T1L-3 Laydoxm Cask N - - 10/15 prig - 0$ CasL - -- A

'FL-4 Laydomna Cask X -- - 10/15 pri~g - 120$F Cask - - A Load Case Horizontal DW Vertical DW Internal E~xternal Thermal Lifting Other Service

_____________ DSC Fuel DSC Fnel Pressuire' Pressure Condition Loads Loads Level Tr.ansfer To/From ISFSI Tl-I Axial Load- Cold Cask X - - 10/15 pai - 0$ IlgAsial - A TR-2 Transverae Load- Cold Cask N - - 10,/1ipai - 0$ lg Trans-erse - A TR-3 Vertical.Load- Cold Cask N - - 10/15 prig - 0?* lgVertical - A TR-4 Oblique Load -Cold Cas X - - I0/15 paig - 0$' % gAxial - A

+ %gTrans

+ %gVert

'FR-i Axial Load- Hot Cask N - - 10/15 prig - 100$F lgAxial - A fl'*-6 Transverse.Load -Hot Cas N - - 10/!5ipsie - 100?F lgTnran - A flR-7 Vertical Load -Hot Cask N - - 10/15ipai - 100$F lgVertdeal - A fl-S Oblique Loat- Hot Cask N - - 10/15ipsig - 100$F Y_-g :zdal - A

+ 'Ag Trans

+ %g Vert.

fl-P 25g Corner Droff'4 2 Note 1,14 Note 1,14 20 prig - I00'"-* ig D 1 t Corner Drop fl-10 75g Side Drop " Note 1 - 20 prig - 1lip* 5 D t

S_ _ _ _ _ sideDrp __

fl-il 'Fop orBoffomfnd Drops"' Note 1,12 20 pr'ig - IC0$"P* tilgEndDrop D

A Calculation No. 11042-0205 Revision No. 1 AR EvA Calculation Page 38of77 Table 1 (Continued) - Summary of Design Basis Load Combinations for the 618TH 080 [Ref. 5.8]

HEM LOADING Horizontal DW Vertical DW* Internal External Tkermal Hanmdling Other Loads Ser-ice DEC Fuel DEC Fuel Pressure~' Preasm#° Condition Loads Level LD-l Normal Loading - Cold Cask X - - 10115 prig -- 0'F Cask +80 Kip -A LD-2 NormalLoading-Hot Cask X - - 10/15peig - l00'F Cask eS0 Kip -- A LD-3 Cask X - - 10/15 psig - 117oF tI0Kip - A w/shade°5

LD-4 Off-Normal Loading--Cold Cask H - - 20 psig - 0oF Cask +S0OKip PP B LD-5 Off-Narmal Loading -Hot Cask X - - 20 psig -1lOO'F +S0 Kip FF B 01 Cask LD-6 Cask X - - 20Opsig 117' F +1S0OKip PP B 51

________ _______ _______ ____________ vt/hade __/_____d_____

LD-7 Accident Loading Cask H - - 20 psig -117' F +80 Kip PP C/I

________________ vt/shade1 __________

HMSOAEHorizontal DW Vertical DW Internal3 External1 Thermal Handling Other Service" HS______STORAGE ______ DSC Fuel DEC Fuel Pressure* Pressure# Condition Loads Loads Level HSM-10ff-Normal HEM X - - 15 paig - -40'F HSM - - B HSM-2 Normal Storage HSM H -- - 15 psig - 0° F HEM - - A HEM-3 Off-Normal HEM X - - l5psig - 117'FHSM - - B HSM-40Off-Normal Tensp. +FaihedFuel HEM X - - 20psig - 117' FHEM - PP C HEM-5 Blocked Vent Storage HEM X - - 65/120 prig - 117' F 41 - D HSM-6 B.V. + Failed Fuel Storage HEM X - -- 65/120psig - HSM/BVt' P

___ ___HEM/BV )

TM HEM-? Earthquake Loading --Cold HEM X - - 10115 prig - 0' F HSM - EQ G.-D' HEM-S Earthquake Loading-Hot HEM X - - 10/15 psig - 100°F HSlM - EQ CGD""

HEM-P Flood Load (50' 11,0) -Cold HEM X - - 10/15 psig 22 psig 0°'F HEM - Floodrt C HEM-10 Flood Load (SO' 11,O) -Hot HEM K - - 10/15 paig 22 psig 100°F HEM - FHoodH) C H.M U'NLOAIDING Horizontal DW VertiralDW Internal External Thermal Handling Other Service

______________ DEC Fuel DEC Fuel Pressures Pressnrem Condition Loads Loads* Level UL-1lNormal Unloading- Cold HEM K - - 10/1l psig - O'F:HEM -60OKap - A UL-2 Normal Unloading -Hot HEM X - - 10/15 paig - 100oFBEM +60OKip - A UL-S HEM K - - 10/I.5peig - 117' F +60OKip - A w/shade UL-4Off-Normal Unloading--Cold HEM K - - 20prig - 0 F HEM +6O Kip PP B EL-S Off-Normal Unloading -Hot HEM H - - 20 psig - 100'F HEM +60 Hip PF B UL-6 1 1 HEM H - - 20psig - 117'F +GOKip PP B EL-? Off. Norm. Unlosding-FF/Hot ( 'u HEM H - - 20psig - w/slsade +10 Hip PP C 1

____ ____ ____ ______________ _________ 100' F HEM _____ _________

EL-S AccidentlUnloading-FF/Hot*'" HEM K - - 65/120*v'psig - 100'F HEM +80 Kap PP RF-1 DEC PReflood - - Cask K 20 prig (max) Hydrostatic. l20° F Cask - - 1

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 39of77 Table 1 (Concluded) - Summary of Design Basis Load Combinations for the 6IBTH DSC [Ref. 5.8]

(Notes for the preceding portions of Table 1)

1. 25g and 75g drop acceleration includes gravity effects. Therefore, it is not necessary to add an additional l.Og load.

2. For Level D events, only maximum temperature case is considered. (Thermal stresses are not limited for level D events and maximum teniperatures give miium allowables).

3. Flood load is an external pressure equivalent to 50 feet of water.

4. BV = HSM vents are blocked.

5. At temperature over LOVEF a sunshade is required over the Tranmsfer Cask Temperatures for these cases are enveloped by the lO0VE (without sunshade) case.

6. As described in Section T.4, this pressure assumes release of the fuel cover gas and 30% of the fission gas. Since unloading requires the USM door to be removed, the pressure and temperatures are based on the normal (unblocked vent) condition Pressure is applied to the confinement boundary.

7. As described in Section T.4, this pressulre asstumes release of the fuel cover gas and 30% of the fission gas. Although tunloading requires the HSM door to be removed, the pressure and temperatures ,are based on the blocked vent condition. Pressure is applied to the shell, inner bottom and inner and outer top cover plates.

S. Not utsed.

9. Unless noted otherwvise, pressure is applied to the confinement boundary. 10*psig and 65 psig are applicable to Type 1 DSC. while 1 5 psig and 120 psig are applicable to Type 2 DSC.

10. Fuel deck seismic loads are assumed enveloped by handling loads.

11t. Load Cases UL-7 and UL-S envelop loading cases where the stresses due to insertion loading of 80 hips are added to stresses due to internal pressure (in reality, the insertion force is opposed by internal pressure).

12. The 60g top end drop and bottom end drop are not credible events, therefore these drop analyses are not required. However, consideration of 60g end drop and 75g side drop conservatively envelops the, effect of 25g corner drop.

13. Conservatively based on normal operating pressure times 1.5 to cover future IOCFR Part 71 requirements.

14. A 2 5 g corner drop analysis (300 from horizontal) of 61BTH DSC without support fromn the TC is to be documented.

15. Sendcc Level C isfor the standardseismic event and Service Level D isfor the high seismic event.

AR EVA Aevi_Calculation A Calculation No.

Page 11042-0205 40of77 Table 2 - Internal Pressure in the 61BTH T, pe 1 DSC MaximumDesign Pressure Maximumused in Ref. 5.2 Calculated adTi Design Condition Pressure Calculation Reference

[psi] [psi]

Normal 7.3 10 Ref. 5.8 Table T.4-16 Oft-Normal 10.9 20 Ref. 5.8 Table T.4-20 Accident 56.1 65 Ref. 5.8 Table T.4-24 Table 3 - Maximum Temperatures in the 61 BTH Type 1 DSC Shell Maximum Design Design Calculated Teprtrused in ThisRernc Condition Temperature CalculationRernc

[°F] [OF]

Storage 374 500 Normal ________ Ref. 5.8 Table T.4-13 Transfer 439 500 Storage 399 500 Off-Normal Ref. 5.8 Table T.4-18 Transfer 416 500 Storage 611 625 Accident _______ _______ ________Ref. 5.8 Table T.4-22 Transfer 467 500

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 41 of 77 Table 4 - Properties of SA-240 Type 304. [Ref. 5.11]

ESm Sui Tep MdEso loal ~Utmt Yield Stress for SL A/B Yield Stress for SL D Strss Yied tres ensle Limit Load Analysis Limit Load Analysis

[°F] Elasticity Sntressit Yie Ste S trensile (Note 1) (Note 2)

[ksi] Intesity ((kstregt [ksi] [ksi]

70 28,300 20.0 30.0 75.0 30.0 46.0 100 28,138 20.0 30.0 75.0 30.0 46.0 200 27,600 20.0 25.0 71.0 30.0 46.0 300 27,000 20.0 22.4 66.2 30.0 46.0 400 26,500 18.7 20.7 64.0 28.1 43.0 500 25,800 17.5 19.4 63.4 26.3 40.3 600 25,300 16.4 18.4 63.4 24.6 37.7 625 25,175 16.3 18.2 63.4 24.5 37.5 700 24,800 16.0 17.6 63.4 24.0 36.8 (1) The yield strength to be used in a Limit Analysis for Service Level A and B Loading is 1.5*Sm, per Paragraph NB-3228.1 of Reference 5.7.

(2) The yield strength to be used in a Limit Analysis for Service Level D Loading is the lesser of 2.3"Sm and 0.7*Su, per Paragraph F-1341.3 of Reference 5.9.

A Calculation No. 11042-0205 Revision No.

AR EVA Calculation Page 42of77 Table 5 -Properties of SA-36. [Ref. 5.11]

E S U Yield Stress for SL A/B Yield Stress for SL D Temp Modulus of Allowable Sy Ultimate LitLodAays LmtLadnlss

[°F] Elasticity Srs YilStes Tnle(Note 1) (Note 2)

[ksi] Intensity [ksi] Strength [ksi] [ksi]

[ksi] [ksi]

70 29,500 19.3 36.0 58.0 29.0 40.6 100 29,338 19.3 36.0 58.0 29.0 40.6 200 28,800 19.3 33.0 58.0 29.0 40.6 300 28,300 19.3 31.8 58.0 29.0 40.6 400 27,700 19.3 30.8 58.0 29.0 40.6 500 27,300 19.3 29.3 58.0 29.0 40.6 600 26,700 17.7 27.6 58.0 26.6 40.6 625(3) 26,400 17.6 27.2 58.0 26.4 40.4 700 25,500 17.3 25.8 58.0 26.0 39.8 (1) The yield strength to be used in a Limit Analysis for Service Level A and B Loading is 1.5*Sm, per Paragraph NB-3228.1 of Reference 5.7.

(2) The yield strength to be used in a Limit Analysis for Service Level D Loading is the lesser of 2.3"Sm and 0.7*Su, per Paragraph F-1341.3 of Reference 5.9.

(3) All values are interpolated from the 600 °F and 700 °F values.

A Calculation No. 11042-0205

, Revision No. 1 AR EVA Calculation Page 43 of 77 Table 6 -Summary of Load Cases and Results Temp.

Aalysis Required/ Colpe CdReurd Cllad SftyFcr Name Mesh [evel Loading Tep nlss Design Pressure Cd eurd Cluae aeyFco

[-°F] Criteria Pressure Ratio Ratio (Note 1)

_______________________ [si][psi]

Internal Initia 500 SL A/B 32 95.9 1.5 3.00 2.0 Prassure InternalI Refined We ds 500 SLA/B 32 94.8 1.5 2.96 2.0

~Pressure u* Refined Welds Internal 6500 SL A/B 32 93.8 1.5 2.93 2.0 E and Lid Pressure Inta Itra Inta nenl 625 SL D 65 136.6 1.11 2.10 1.9 Pressure Refined Welds Internal 625 SI D 65 132.6 1.11 2.04 1.8 and Lid Pressure

' ~Refined Welds Internal 500 SLA/B 32 93.7 1.5 2.93 2.0 and Lid Pressure E

.* Refined Welds Internal 625 SI D 65 132.9 1.11 2.04 1.8 and Lid Pressure o* Refined Welds Internal

anLd Prsue 500 SI A/B3 32 94.5 1.5 2.95 2.0 z

0m* Iiil Itra 500 51A/B 32 97 1.5 3.03 2.0

.L* (Note 2) Pressure Temp. Analysis Reurd olpe Code Required Calculated Safety Factor Name Mesh Level Loading Design G-Load G-Load

[-oF] Criteria Ratio Ratio (Note 1)

Initial Side Drop 500 SI D 75 181 1.11 2.41 2.2

" Refined E Circumferential Side Drop 500 5L D 75 lBS 1.11 2.47 2.2 6

. Mesh (Note 3)

IntaSSdOrp ih 50 5L D 75 181 1.11 2.41 2.2 (Note 3) Off-Normal IP

Eo Initial Side Drop 500 SL D 75 189 1.11 2.52 2.3 Notes:

ri0) Rows in bold represent the best-estimate, i.e. "Final", results.

l) This is the Calculated Ratio divided by the Code Required Ratio.

r2)The 97 psi collpase load is estimated / extrapolated from the final obtained solution at 95 psi. Excessive run times mate more precise results impractical.

3) The reported collapse load is conservative - based on the collapse behavior it is expected that smaller analysis time steps would yield larger collapse

]loads. This was deemed impractical due to the long run time and the large margin available.

A Calculation No. 11042-0205 Revision No. 1 A R E VA Calculation Page 44 of 77 Figure 1 - Sketch of the 61BTH DSC Top End and Transfer Cask from Reference 5.1

A Calculation Revision No. 111042-0205 AREVA Calculation Page 49 of 77

-2+14 0.195"H, FULL CIRCUMFERENTIAL OTCP Weld Metal (ITCP Not Shown)

Figure 7 - OTOP Flaws - Bounding Set #1 for ANSYS Collapse Analysis

-14 ,

0.07 "H, FULL CIRCUMFERENTIAL OTCP Weld Metal (ITCP Not Shown)

Figure 8 - OTCP Flaws -Bounding Set #2 for ANSYS Collapse Analysis

A Calculation No. 11042-0205 Revision No. I AREVA Calculation Page 50 of 77

~OTCP

/--ENVELOPE OF ALL BUT 7 AND 11

/MAX IND IV. HEIGHT IS 0.09" Weld MetalK MAX INDIV. LENGTH IS 2.09"

,,-11 (7.17"L x .09"H, REMOTE FROM ALL OTHERS 7 (10.34"Lx 0.11"H, NEAR FLAWS I THRU 9)

ITCP Figure 9 -ITOP Flaws - Raw Data from Reference 5.1 OTCP

-REPRESENTATIVE GROUP FLAW 0.09"H, FULL CIRCUMFERENTIAL Weld Metal 7

0.1 1"H, FULL CIRCUMFERENTIAL ITCP Figure 10 - ITOP Flaws - Bounding Flaw Set for ANSYS Collapse Analysis

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 51lof 77 AIJSYS 14.0 MARl25 2015 10:36:49 ELEMENTS PowerGr aphi cs EFACET-1 TYPE NUN IV -1 D15T-53. 812 XE -16.8125 YE -146.88 2-BUEFER L-x Figure 11 - Overview of the Axisymmetric Model P NSyS 14.0 SMAR 25 2015 1 0: 37:28 SELEMENTS PoeGraphics EEACET-1 STYPE NUM ZV -1

'018T-7. 49924

'*XE -31.8932

'YE -190.433 SZ-BUEEER Figure 12 - Mesh Details Near the Lid Regions of the Axisymmetric Model (Small differences in the mesh exist amongst the sub-models)

A Calculation No. 11042-0205 Revision No. 1 A R E VA Calculation Page 52 of 77 MNAR25 2015 Power~raphice EEACET-1 TYPE NUN 2V -1

DIST-I. 27O14

XF -32. 6238

YF -194. 594 2 -BUFFER Figure 13 - Mesh Details at the Welds for Axisymmetric Case #1 ANSYS 14.0 MAR 25 2015 10:45:35 ELEMENTrS Power~raphics TYPE NUN ZV -i

+DTSTI'-.27014

XF -32.6238

YF -194.594 Z-BUFFER Figure 14 - Flaw Locations for Axisymmetric Case #1

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 53of77 SAPR 21 *5 11:44 5 EL NTS P e rGraphicm EFACET-i

/TYPE NUN n ~*DIST3. 78456

XF -30. 6287 I*YF =193. 906 SZ-BUFFER Lx Figure 15 - Refined Mesh (Weld Region) for Axisymmetric Case #1 ANSYS 14.0 _______

APR 21 20*

11:42:1}

/TPE NUM

~ZV -1

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Y -194.043 Z -BUFFER Lx Figure 16 - Refined Mesh (Weld and Lid Interior Region) for Axisymmetric Case #1

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 54of77 A2JYS21 14.0 API. 2015 14:52:50 ELE4EJT Eo.wer=ph1 Cs EFA.Z *1

i*T$-3. 12647

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DISTI.1 23285

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YF -194.*652 Z -BUFFER EDGE Figure 18 - Flaw Locations for Axisymmetric Case #2

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 55of77 A~NSYS 14.0 APR 21 2015 14:38:39 ELEMENTS PowerGraphics EFACET=I TYPE NUM YV =-1 DIST=53. 812 YE =16. 8125 ZF =146.88 Z-BUFFER EDGE Z

Figure 19 - Overview of the Half-Symmetry Model

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 56of77 ATPR 24.205 A9Y31 14.0 APR 1 215 AY 4 2019 14,79= 52 1X0 ELEM9ENTS £LE1PTS Pvnt

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(a) Lid Region Solid View (b) Lid Region Mesh

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A Calculation No. 11042-0205 Revision No. I AR EVA Calculation Page 57of77 ANSYS 14.0 MAY 4 2015 10:04:39 ELEMENTS Powe rGraphics EFACET-1 TYPE NUM xv --. 373471 YV --. 679348 i ~ZV -.631669

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A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 58of77

~ANSYS 14.0 MAY 4 2015 10:22:15 ELEMENTS Pow. rGraphics EFACET=.1 TYPE HUM XV --. 290468 YV --. 652082 lV -. 700299

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'ZF 5165.967 A-ZS-e33. P5]I)

Z-BUrrER Figure 22 - Isometric Views of Half-Symmetry Model (Refined Circumferential Mesh)

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 59of77 Asxsy$ i4.0 A648YS 14.0 APR 21 2011 APR 21 2015 NODAL SOLUTION NODAL SOlUTION STEP-2 STEP=3 S*J ..i 1(2 -4 T0161-20 TIME-65 EPLEQV {AVG) EPPLEQV (AVO(

POWx :G~6ph 08 Powe r r aphliM EMAOE'1'- EFAC6T-1 AVRES-Hat AVERS-Mat DM .1629 1649 -. 647348 8149- 002675 SMX-.547214 m .2979 03 .005246

.5945-03

.8925-03

- .010492

- .001109 -i .015738

.020964 mm 001486 .02622

__ .001703

(( 00200

-EJ[ .031476

.036722 m

.002378

.002675

- .041966

.047214 (a) Equivalent Plastic Strain in Weld Region [in/in] (b) Equivalent Plastic Strain in Weld Region [in/in]

at 20 psi Internal Pressure at 65 psi Internal Pressure 1 r69,

,=,s ,.o 5 14.0 APR 21 2011 ,* 210:41:5 10:41,53 I1:15 NODAL.SOLSTE4J NODAL SOLUTION 0 TE6=4 STIP-4 TIME-95. 8249 TIME--95. 9249 IPP*LEQO (AVG) E*PLEQV (AVO*

P~,poGEhics Eo'eD~raphisC SPACES-S 6FACET-I AVERS-Mat AV*ES-Mat DM2 =15.0267 DM0 =11.0261 5160-3.36;918 616 -1.25091 m .374353 .1289

.746707 .277901

" .12306 _________________________________ .416972 1.49741 .515962 2.24612 . 694903 2--

.62047 = 3.972994 2.994031112 3.369281.21091 (c) Equivalent Plastic Strain in Weld Region [in/in] (d) EQV Plastic Strain in the Cover Plates at 95.9 at 95.9 psi Internal Pressureps Figure 23 - Results for Axisymmetric Case #1 - Initial Mesh - Service Level A/B

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 60of77 ANSYO 14.0 AEV*21 2015 10:41:55 PoSIT26 try 25 IV -1 22 .5 012T-.75 XF=5 YF -. 5 26 15F -. 5 I 4BUFUER 15 2

12.,5

.5 2.5 o

I) 19.1166 26.3"3 52.553 lw 36.744 J i 95.925 1.5923 20.22* 42.665 62.191 11#.232 Inttetn~5 Irt96ur# 4pi)

(a) Service Level A/B Material Properties ANSYS 14.0 AE* 21 2015 10:44:01 1'S~T24 42 26 DIST-. 75 YF-.5 1 -BUFFER 12

22.316 54.2 6*3 1.654 169.232 136.59 13.659 46.622 69.265 9.613 222.931 (b) Service Level D Material Properties Figure 24 - Deflection History of the Center of the OTCP for the Axisymmetric Case #1 Initial Mesh (Maximum deflection occurs at the center point of the lids, in the outward axial direction)

(Note that the magnitude of the deflections has no true physical meaning due to the nature of limit load analysis)

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 61lof 77 ANSYS 14.0 6SUYS 14.0 ABB 21 2515 ABS 21 2011 10;45.33 10:45: 35 NODAL SOLOTWON NODAL SOLUTrS1 STE¢P-S STEP,.S SUE8 -1 SUB -7 TDIW-20 rSM4E-6,5

£PPI.!QV (A '1 E PPISQ (AV'2(

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. 10241

.006994 nn .007666

- .11104

,i .. 13, (a) Equivalent Plastic Strain in Weld Region [in/in] (b) Equivalent Plastic Strain in Weld Region [in/in]

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Bvwr*Graphscs P~~ah EBACWT-1 EPACBT..1 AVUES-Nat AVP.ES-Kat SES -2 .03601 ES-526 3 .676691 904621

________________________________ .I13

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455523 2:03601 .512463 (c) Equivalent Plastic Strain in Weld Region [in/in] (d) EQV Plastic Strain in the Cover Plates at 94.8 at 94.8 psi Internal Pressure psi Figure 25 - Results for Axisymmetric Case #1 - Refined Mesh in Weld Region - Service Level A/B

A Calculation No. 11042-0205 Revision No. 1 A R E VA Calculation Page 62 of77

019110 14.0 MISTS 14.0 APR 21 2015 APR* 21 2015 I10=47:01 10;4"/:07

!NODAL SOLU*TION NODAL SOLUTION 00 * .. 1 009 =7 EP#L132V IA*)I EPPLEQY (AVG) 0'oWorGr~hlco PoNO*aphl c9 I*PAET'IEFACET-1 AV#ES-N AVR.ES,-Xat 0141 -. 009331 0301 -. 147566 m .o2, 0*2m mm .oo03124 m .,

.o004165 E .~~

] .oo042e4[7* n

.000329 .,13317 m :009371 m . 14756*

(a) Equivalent Plastic Strain in Weld Region [in/in] (b) Equivalent Plastic Strain in Weld Region [in/in]

at 20 psi Internal Pressure at 65 psi Internal Pressure AllOYS 14.0 AN(SYS 14.0 APR 2.2 2015 APR 22 2015 10;47o09 10; 47; 14 0T100-4 571,-4 0100 -10 0010 -10 T1149-93.7124 TINE.93. 7224

&PPLEOV (AVGI EPPLEQY (AVO)

RFACET-I.F1E-AVOES-Mat: AVRES0.Na 10143 .10.3052 191 -10.3062 0142t-1.94282 0345 -. 420095 m':10o9 431739 9

[

.m 46

.093352 m .4347m .140601 mm 79,347 .233291 1291..o9004 EJ(( 10195100 .324733 132696.373005 m 1:94292 mm .420005 (c) Equivalent Plastic Strain in Weld Region [in/in] (d) EQV Plastic Strain in the Cover Plates at at 93.7 psi Internal Pressure 93.7 psi Figure 26 - Results for Axisymmetric Case #1 - Refined Mesh in Weld and Lid Interior Region - Service Level A/B (Note (c) and (d) are plotted one timestep before the collapse pressure)

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 63of77 ANOYS 14.0 APP.21 2015 10145143 POSTI4 lV -I 11.21 0IST-. 75 2SF -.5 Y¥-. 5 ZI -. 5 "7.5

.4 6.25 . .

1.15 12.5 6I 16.954 17.911 ,4.96 75.614 94.7"79 9.477 26.431 41.365 46.339 95.243 Material Properties Only (a) Service Level A/B Weld Region (a) Service Mesh Level atA/B Material Properties Refined Refined Mesh at Weld Region Only A2SSYS14.0 APP.21. 2011 10.'49.14 POST24 lv -1 OIST-. 75 2SF -. 5 YF -.5 SF -. 5 Z-PIJFSPR 6.572 16Es.744 21.446 26.154i 14,232 14.97T4 93.723 44.86 43.464 6*4.324 (b) Service Level A/B Material Properties Refined Mesh at the Weld and Lid Interior Regions Figure 27 - Deflection History of the Center of the OTCP for the Axisymmetric Case #1 Refined Mesh (Maximum deflection occurs at the center point of the lids, in the outward axial direction)

(Note that the magnitude of the deflections has no true physical meaning due to the nature of limit load analysis)

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 64of77 4.00 3.50 3.00 -Initial Mesh

.......... Initial Mesh, Enhanced formulation 2.50 -- --- Refined Mesh (Welds)

- -Refined Mesh (Welds and Lids)

,.*2.00 E

E 1.50 1.00 0.50 0.00 0 20 40 60 80 100 120 Internal Pressure [psi]

Figure 28 - Comparison of Maximum Displacement Histories for Axisymmetric Model Sensitivity Studies (Maximum deflection occurs at the center point of the lids, in the outward axial direction)

(Note that the magnitude of the deflections has no true physical meaning due to the nature of limit load analysis)

(Service Level A/B material Properties)

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 65of77 200__ j 1.80I

- - Refined Mesh (Welds and Lids) j/

1.20 (1 0,0 0.60 OAO 0.20 0.00 0 10 20 30 40 5O 60 70 80 90 100 Internal Press.ure [psi]

Figure 29 - Comparison of Maximum Displacement Histories for Axisymmetric Model with Lid Contact Defined using Nodal DOE Couples vs. Contact Elements (Maximum deflection occurs at the center point of the lids, in the outward axial direction)

(Note that the magnitude of the deflections has no true physical meaning due to the nature of limit load analysis)

(Service Level ANB material properties)

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 66of77 4.00 ,

350) 3.00 .. *

Refr,ed Mesh (Welds andtLids) 2.50

.2.N 1.50 1.00 0.50 10 20 30 40 50 60 70 80 90 100 Internal PreSSure lpsi]

Figure 30 - Comparison of Maximum Displacement Histories for Axisymmetric Model With and Without Pressure Loading Applied to the ITCP Weld Root Flaw Faces (Maximum deflection occurs at the center point of the lids, in the outward axial direction)

(Note that the magnitude of the deflections has no true physical meaning due to the nature of limit load analysis)

(Service Level A/B material properties)

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 67 of 77 M3011$ 14.* h*YS 14.0 330- 21 2315 12.201.1GI 15*0*t2215l0El22 NODAL10o3LrU21 UODAL ;97LUTI*X SE8'2 9TEP33 T093020 5190-65 3ovwrotehlcs toW* rtlaphies 320 =..09 61.2 SNX -. 149921 mm .oo4*9 * .033294 I .00204

04994

.002*9 - ,04659?

(a) Equivalent Plastic Strain in Weld Region [in/in] (b) Equivalent Plastic Strain in Weld Region [in/in]

at 20 psi Internal Pressure at 65 psi Internal Pressure 913011 40 9501 14.0 fiA*h 21 2o25 335 21 2015 I NO*S*UIt 032133 SOL*TlI3 291I-93. 6057 Tfl4E..3. 605?

1331.00 (310) 0301.001Q (AVG) 18'ACEI.1 EFAdIT-i

!AVf, E0.4a4 t AV3.Es-06at 0)01 .20.9275 0403 .20.9315

414206 .01*666

. 848411~ .023222

2. 12103 [ 003332 LZJ.296944 t67 3.39365116, (c) Equivalent Plastic Strain in Weld Region [in/in] (d) EQV Plastic Strain in the Cover Plates at at 93.6 psi Internal Pressure 93.6 psi Figure 31 - Results for Axisymmetric Case #2 - Refined Mesh in Weld and Lid Interior Region - Service Level A/B (Note (c) and (d) are plotted one timestep before the collapse pressure)

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 68of77 AIY iAPR, 21 2015 APR 21 2015

'4.

SEP-2 SE*

Sos S1 UB -3 IEPPLQV (AVG) £P10V (A*

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!PACX*P-1 EPAC8E-1 AVFX$-+Mat PSMa 515-.009082 018 -. 139904

.004009 .0*1554 m 001045 .077724 I 00*o406.21 (a) Equivalent Plastic Strain in Weld Region [in/in] (b) Equivalent Plastic Strain in Weld Region tin/in]

at 20 psi Internal Pressure at 65 psi Internal Pressure 685533S14.0* AWSS 14.0 APR 21 2010 APR 21 2011 I:10:38:15 10:38:21 STTEP-4 012!- IISU s -9

TIME'94.015 TIME -94.015 EPPLEQY (AVG) EPPLEOV {A3V3 pow*E*rq~hhc P( oU~02rphlcs r * -4"05956

I VEx -4.05,56 MiKO*

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- .09371.003871 17574 mm2.351 _______________________________

m1 .007741

.011612 2357405 .015483

.446857 m .014303

.536229 i * .027224 iJF- *5;L- .027o05

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A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 69of77 4.00 3.50

,I

-Axisymsmetric Case #1 3.00 Iii ,

Axisymmetric Case S2 2.50

- -- - Axisymmsetric Case a0 (No Flaws) i#

iI 1.50 I/ ,

j 1.00 0.50 0.00 10 20 30 40 50 60 70 80 90 100)

Internal Pressure [psi)

Figure 33 - Comparison of Maximum Center-of-Lid Displacement Histories for the Various Flaw Models (Service Level NB material properties)

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 70of77 371510 14.0 A0170S 14.0 NAY 4 2*016 MAY 4 2015 1013,6119 101361 30 NODAL$OLU'TDO7 NODAL SOUTIONOI STEP-2 STEP-I iSOD-I DUB -2 iTDME-2o TDME-65 EPI*LEQY jAVI31 E*PPLV (AVO)

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.,,7,-0, m .011,

.993-m .0229

.001142 .0257

] 00149 U .04165

.001736 .047599

°001997 .034 m :023 .063549 (a) Equivalent Plastic Strain in Weld Region [in/in] (b) Equivalent Plastic Strain in Weld Region [in/min at 20 psi Internal Pressure at 65 psi Internal Pressure

- r *.,o 32N2y2 AY 4 14.0 2015 T77T*9 EPPLEQO AVO)

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,$25* [] 002 504 "U *2* .007511 atIntrnal1Pessur 95 si (c)) EquivalentcPlastic Strain invWeldlRegiont[in/ini Figure 34 - Results for Half-Symmetry Case #1 Internal Pressure Loading Benchmark Analysis - Service Level A/B

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 71lof 77 4.00 3.50 3.00 S2.50 2.00

1.50 0.50 0 10 20 30 40 50 60 70 80 90 100 Internal Pressure [psi]

Figure 35 - Benchmark of the Half Symmetry model with the Axisymmetric Analysis (Service Level A/B material properties)

A Calculation No, 11042-0205 AR EVA Calculation Page 72of77 i ~ANY 0S 14.0 MA.*Y 4 *015 10 30'0 10=49 : 42 422T**

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- -5 IME-75 TI*-75 £1.LJQV 4AV04 51421 07900{'4 MA 30522

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115.31 .t4*o 21 1Z'14 (a) Equivalent (von Mises) Stress [psi] at 75g (b) Equivalent Plastic Strain in Weld Region [in/in]

at 75g.

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,441 133 2l71.5 .31

~45*7 Mses)Strss psi]at 81g (c)(vnquialen (d) Equivalent Plastic Strain in Weld Region [in/in]

(c) (vn 81gat quialenpsi]at Mses)Strss 181g.

Figure 36 - Equivalent Stress and Plastic Strain Plots from the Half-Symmetry #1 Side Drop Analysis

AR EVA Aevi_Calculation A Calculation No.

Page 11042-0205 73of77 ANISYS 14.0 MAY 4 2015 10: 55:29 NODAL SOLUTION STEP-4 SUB -15 TIME-180. 545 USUM (AVG)

RSYS-0 Powe rGraPhic EFACET-1 AVRES-NMat~

DNX *.340414 SMX -. 340414

,,m.037824 m 075647

-. 113471

--. 264766

-. 3o2 59

-l .340414 (a) Deformed Shape Plot - Axial View - Exaggerated Scale ANSYS 14.0 MAY 4 2015

,--*.*10:56:19

',NODAL SOLUTION STEr-4

"" "*" IME-180. 545

',::,,,USU.M (AV$-)

, RSYS-.0 PowerGraphics E1FAcI~r-1 AVRES-MRt D1= .340414

, MX -. 340414 I1.037824

°075647

.113471

/' *'1) ]m .151295

.151295

.226942 I .30259 mm .340414 (b) Deformed Shape Plot of DSC Shell - Axial View - Exaggerated Scale Figure 37 - Additional Results Plots from the Half-Symmetry #1 Side Drop Analysis

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 74of77 A.81Y0 14.0 1}.891 14.0 EAT 4 215 MAt 4 2015 14:80:57*

24,50:34 NODAl. DOLOTI*

$ow -5 Tm.781:=7 T~~l*=?IO IAVO)Q *VS 1)9-.160235 389 -.263485 8)0 -16.84Q0__

189 -53962.0 .01915 I *,0,.*. ! .S*4495 17990.7 090953 (a)(vn Mses Stess psi at75g(b) quialet Equivalent Plastic Strain in Weld Region [in/in]

Stess psi(vn Msesquialet (a) at75gat 75g.

882$Y0 14.*

1. 24.0 04SY MAY 4 Z0.5 MAy 4 2015 14.5:5236 14:"52:00 NODAL SOLUYTIONI NODAL 201.0T209 SlE1-4 TtM8-I80 . 604 E*PFIJV *A*Pl 1.093-8a00 DM9 -. 524096 89 -45.2367 _0 089 -50519 ,283 45 . - 314 1128I*3.9 .955.5*

28091 .S*1. 71941 m 44919 7 (c)Equvaent(vo Mses Stes [pi]at 181g (d) Equivalent Plastic Strain in Weld Region [in/in]

[si]at (vn quialen (c)Mies)Stres 181g.

Figure 38 - Equivalent Stress and Plastic Strain Plots from the Half-Symmetry #1 Side Drop Analysis with Off-Normal Internal Pressure

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 75of77 9000 14.0 Al600s 14.0 HAY 6 2016 MA 2011 15416

13. 50,09 I9DA OOLUTL3IN SL* -5 1U75 1946-7t5 50E2V'Eg' (AVe,)

Pov~~z~hes EACET-X i E£AET-IAVIES-Mat AVE$.44. *-X .. 067129 195-.067129 3946 -. 030464 04-Z2. 9722III 0 095-10040.4

038 5580.4 m 020115 22252.9 052031

7*04

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at 75g.

996050 14.0 9497 6 .019 9465 6 2015 I1354, 34 13~ 1,1 99191SOLUT ION 960091*A0012)21ST,9- StTEP--

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332*.Z. 0*.4044 i 44 04 6 49594, 4 (c) Equivalent (von Mises) Stress [psi] at 185g (d) Equivalent Plastic Strain in Weld Region [in/in]

at 185g.

Figure 39 - Equivalent Stress and Plastic Strain Plots from the Half-Symmetry #1 Side Drop Analysis with Refined Circumferential Mesh

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 76of77 AN*¥* 4.i* Ay 4 .012 113. 4 20 5 13:37:23 12:;C4:23 NODAl, 2(0.03200 2343,-2 33 -5 011 V (AV<G we ahc 2112 07497 -147243 m 2239 99 .049114 m *33444 3098*

- 44422.9 aleses Stess psi at75g(b) t (y quin M (a) Equivalent Plastic Strain in Weld Region [in/in]

(a) Stess psi(vn Msesquialet at75gat 75g.

3.1133 24.3 PlAY 4 2322*

113. 4 2322 m 2:34:73o 37WT.C3 141A'EE-I. 03113-4 SMN -334.-27 034.27 m 141-19.4 1IK4~23,343 4? 143V (I2I 31Ž22 (77. r*h 01111 at41899.

Euialn0Sres Fiur 4 n Strain9 2Pasi rmteHafSmer 0 N w)Sd U.t34437 1 Analysis442

A Calculation No. 11042-0205 Revision No. 1 AR EVA Calculation Page 77of77 0.80 T __ ____T tI

' * ~3 D-i1 Side Drop i 0.60 .... 3D-1 Side Drop w/Internal Pressurei to "3-SideDopwt RefinedCircumferential Mesh

_0.0

--- Initial deflection due to 20 psi off- __ __ _.."__ __ __ ""__ /___

! "17 * ~~normal pressure applied in.".""

= 0.30 I---acceleration ramped linearly.-"

0.20 -- _ _ . ... ... . .. . _,_-_:'-'I

~...... . . . .-. .- ' . ..... ....

0 20 40 60 80 100 120 140 160 180 200 Acceleration [8]

Figure 41 - Comparison of Maximum Displacement Histories for the Various Half-Symmetry Analyses (Service Level D material properties)

L-MT-1 5-056 ENCLOSURE 4 AREVA CALCULATION 11042-0205, REVISION 1 TITLE:

6IBTH ITCP AND OTCP CLOSURE WELD FLAW EVALUATION 77 pages follow

CONTROLLED COPY E-203 A ACalculation TIP~or3 .2-RvIn10 Calculation Cover Sheet No.

Revision No.

11042-0205 I

A R E VA . Rvso 0 Page Iof 7 DCR NO (if applicable): PROJECT NAME: NUHOMSe 61BTH Type 1 DSCs for 11042022 Rv. 0Monticello Nuclear Generating Plant PROJECT NO: 11042 CLIENT: Xcel Energy CALCULATION TITLE:

61B8TH ITCP and OTCP Closure Weld Flaw Evaluation

SUMMARY

DESCRIPTION:

1) Calculation Summary This calculation qualifies Monticello DSC-16, a 61B8TH Type I DSC, for all design basis loads in consideration of observed flaws in the Inner Top Cover Plate (ITCP) and Outer Top Cover Plate (OTCP) closure welds.

2) Storage Media Location

- Coldstor -/areva...nh11042/I11042-0205-000 If original Yes El Issue, No is 0]

licensing (explainreview below)per TIP 3.5 required?

Licensing Review No.:

This calculation is prepared in support of license exemption request which will be reviewed and approved by the NRC. Therefore, licensing review per TIP 3.5 is not required.

Software utilized (subject to test requirements of TIP 3.3): Software Version: Software Log ANSYS14.0Revision R-29 Calculation is complete R..c,,* *0..o, ** "**":- Date:

Originator Name and Signature: Jeff Pieper c*y/c.-

o/1 Calculation has been checked for consistency, completeness, and correctness Date:

Checker Name and Signature: Gabdiel Lomas (2 "Y'

'* *./ 5 Calculation is approved aead*ntuse for USpoetEgne