L-MT-14-016, Calculation 11042-0204, Revision 2, Structural and Allowable Flaw Size Evaluation of the Spent Fuel Storage Canisters with Nonconforming Closure Welds at Monticello Nuclear Generating Plant
| ML14199A372 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 07/07/2014 |
| From: | Honrao A AREVA |
| To: | Office of Nuclear Material Safety and Safeguards |
| Shared Package | |
| ML14199A369 | List: |
| References | |
| L-MT-14-016 11042-0204, Rev. 2 | |
| Download: ML14199A372 (18) | |
Text
L-MT-14-016 ENCLOSURE 3 AREVA CALCULATION 11042-0204, REVISION 2 NON-PROPRIETARY VERSION STRUCTURAL AND CRITICAL FLAW SIZE EVALUATION OF THE SPENT FUEL STORAGE CANISTERS WITH NONCONFORMING CLOSURE WELDS AT MONTICELLO NUCLEAR GENERATING PLANT 15 pages follow
Non-Proprietary Version Calculation No. 11042-0204 Form 3.2-1 Calculation Cover Sheet Revision No. 2 A R EVA TIP 3.2 (Revision 6) Page: 1 of 15 DCR NO (if applicable).: DCR 11042-020 PROJECT NAME: NUHOMSO 61 BTH Type I DSCs for Monticello Nuclear Generating Plant PROJECT NO: 11042 CLIENT: Xcel Energy CALCULATION TITLE:
Structural and Allowable Flaw Size Evaluation of the Spent Fuel Storage Canisters with Nonconforming Closure Welds at Monticello Nuclear Generating Plant
SUMMARY
DESCRIPTION:
- 1) Calculation Summary This evaluation addresses the suitability for use of certain 61 BTH Type I Dry Shielded Canisters (DSCs) currently deployed at the Monticello Nuclear Generating Plant (MNGP) with field closure welds that are noncompliant with respect to the technique utilized for the liquid penetrant (PT) examination process.
The calculation evaluates the structural integrity of the NUH61 BTH Type 1 DSC for a reduced closure weld and calculates the allowable flaw size.
- 2) Storage Media Description Secure network drive initially, then redundant tape backup.
If original issue, is licensing review per TIP 3.5 required? N/A I Yes EL No EL (explain below) Licensing Review No.:
Software Utilized (subject to test requirements of TIP 3.3): Version:
ANSYS 14.0.3 Date:
Calculation Is complete:! Date:
Originator Name and Signature" Abhijit Honrao Calculation has been checked for consistency, completeness and correctness Date:
Checker Name 4nd Signature: Veeresh ayagavi Date:
Calculation is approved for use: Peter Digitay signed O:
by WteiQunlnan
,cnpetrontrannuta Quinlan..."
Project'Engineer Name and Signature:
Qronect EatN
'Pete Quinlan 2014a07a071gt:183Q-04W
Calculation No. 11042-0204 Revision No. 2 AR EVA Calculation Page 2 of 15 REVISION
SUMMARY
Affected Affected Rev. Description Pages Disks 0 Initial issue All All 1 Excel Energy comments yincorporated. 1-11,13 None and 14 Correct editorial error on Table 4 and Table 6. The nodal 2 force reported should be "Ibs" instead of "kips". Add 1,2, 13 and None clarification about nodal force and force/in in Table 4 14 through Table 7 per DCR 11042-020, Rev. 0.
Calculation No. 11042-0204 Revision No. 2 AR EVA Calculation Page 3 of 15 TABLE OF CONTENTS Page 1 .0 P UR P O S E .......................................................................................................................................... 4 2.0 CONSERVATISM / ASSUMPTIONS ............................................................................................... 4 3.0 DESIGN INPUT/DATA ........................................................................................................................ 4 3.1 W eld Reduction Factor ....................................................................................................... 4 3.2 Safety Factor ............................................................................................................................. 5 3.3 Bounding Load Combinations ................................................................................................. 5 4.0 METHODOLOGY ................................................................................................................................ 5 4.1 DSC Evaluation for Reduced W eld Evaluation ...................................................................... 5 4.2 Allowable Flaw Evaluation ..................................................................................................... 5 4.3 Limit Load Analysis .................................................................................................................... 6
5.0 REFERENCES
................................................................................................................................... 7 6.0 NOMENCLATURE .............................................................................................................................. 7 7.0 COMPUTATIONS ............................................................................................................................... 7 7.1 OTCP W eld for Reduced W eld Size Evaluation ..................................................................... 7 7.2 Allowable Flaw Size Evaluation ............................................................................................. 8 7.2.1 W eld Post-Processing and Stress Calculation .......................................................... 8 7.2.2 Determination of Allowable W eld Flaw Size .............................................................. 8 8.0 RESULTS ........................................................................................................................................... 9
9.0 CONCLUSION
S .................................................................................................................................. 9 10.0 LISTING OF FILES ........................................................................................................................... 10 LIST OF TABLES Page Table 1 Controlling Load Combinations Stress Results for the non-compliant OTCP Closure Weld (Primary S tres s ) ................................................................................................................................ 11 Table 2 Controlling Load Combinations Stress Results for the non-compliant OTCP Closure Weld (Secondary Stress) ............................................................................................................. 11 Table 3 Safety Factors for Circumferential Flaw (Ref. [5.1]) ................................................................... 12 Table 4 Weld Stress Results of Outer Top Cover Plate Welds for Individual Loads ................ 13 Table 5 Load Combination Weld Membrane Stress (o-) Result for Outer Top Cover Plate Weld ...... 13 Table 6 Weld Stress Results of Inner Top Cover Plate Welds for Individual Loads ................................ 14 Table 7 Load Combination Weld Membrane Stress (o"',) Result for Inner Top Cover Plate Weld ...... 14 LIST OF FIGURES Page Figure 1 Subsurface Crack Model for ITCP and OTCP W elds ............................................................... 15 Figure 2 Surface Crack Model for ITCP and OTCP W elds ..................................................................... 15
Calculation No. 11042-0204 Revision No. 2 AR EVA Calculation Page 4 of 15 1.0 PURPOSE The calculation evaluates the structural integrity of the NUH61BTH Type 1 DSC for a reduced OTCP closure weld of 0.48" instead of the 0.50" stated in the design and calculates the allowable flaw size for ITCP and OTCP closure welds.
2.0 CONSERVATISM / ASSUMPTIONS
- 1. The weld allowable flaw size is based on radial tensile membrane force acting on the weld, however it is conservatively evaluated based on SRSS method excluding the compressive stresses in the weld.
- 2. The secondary loads would tend to reduce with the reduction in stiffness of a component. However, conservatively the secondary stresses are scaled, increased, for the reduction in the OTCP weld size.
3.0 DESIGN INPUT/DATA 3.1 Weld Reduction Factor Proprietary Information Withheld Pursuant to 10 CFR 2.390
Calculation No. 11042-0204 Revision No. 2 AR EVA Calculation Page 5 of 15 3.2 Safety Factor Safety factors used to determine the allowableflaw size are taken from Appendix C, Section C-2621 of Ref.
[5.1].
3.3 Bounding Load Combinations All bounding normal, off-normal and accident load combinations are taken from Ref. [5.2].
3.4 OTCP Weld Depth The minimum depth of the partial penetration OTCP to Shell closure weld is 0.48" [5.8]
4.0 METHODOLOGY 4.1 DSC Evaluation for Reduced Weld Evaluation The noncompliant closure welds with respect to the liquid penetrant (PT) examination process are the OTCP and ITCP closure welds. However, only the OTCP plate closure weld is not completely filled and minimum measured weld is found to be 0.488". The OTCP plate closure weld stresses are reevaluated for a throat size of 0.48". The ITCP weld where the weld preparation depth of 3/16" is fully filled has no reduction in the weld area.
All the DSC components primary loads (membrane and bending) are evaluated assuming the closure welds as line welds, i.e. pin connection. Hence, the existing evaluations performed in Ref. [5.2] for primary loads for all the DSC components except the OTCP weld are unaffected by the non-compliant closure welds.
The thermal loads which are secondary loads would tend to reduce with the reduction in stiffness of the components. Hence the existing evaluations performed in Ref. [5.2] for secondary loads would remain bounding for all the components. However, conservatively all secondary stresses are scaled for the 0.48" weld.
Hence, the existing evaluations performed in Ref. [5.2], remain bounding for all the DSC components, except for the OTCP closure weld. The OTCP closure weld is reevaluated in Section 7.1 4.2 Allowable Flaw Evaluation Proprietary Information Withheld Pursuant to 10 CFR 2.390
Calculation No. 11042-0204 Revision No. 2 AREVA Calculation Page 6 of 15 Proprietary Information Withheld Pursuant to 10 CFR 2.390 4.3 Limit Load Analysis Proprietary Information Withheld Pursuant to 10 CFR 2.390
Calculation No. 11042-0204 Revision No. 2 AR EVA Calculation Page 7of 15
5.0 REFERENCES
5.1 ASME Boiler and Pressure Vessel Code,Section XI, Division 1, Appendix C, 2004 edition through 2006 Addenda.
5.2 TN Calculation NUH61BTH-0200, Rev.0 "NUHOMS-61BTH Type 1 Dry Shielded Canister Shell Assembly Structural Analysis".
5.3 ANSYS Computer Code and User's Manual, Release 14 (used only for post processing results).
5.4 ISG-15, Rev. 0, "Materials Evaluation".
5.5 ASME Boiler and Pressure Vessel Code, Division 1, Subsection NG, 1998 edition through 2000 Addenda.
5.6 TN Calculation No. NUH61 BTH-0403, Rev. 0, "NUHOMS-61 BTH DSC Thermal Evaluation for Storage and Transfer Conditions".
5.7 T.L. Anderson, "Fracture Mechanics, Fundamentals and Applications", Second Edition.
5.8 TN Engineering Evaluation No. 11 042-EE-001, "Monticello Nuclear Generating Plant: Engineering Evaluation of Spent Fuel Storage Canisters with Nonconforming Closure Welds".
6.0 NOMENCLATURE ITCP: Inner Top Cover Plate OTCP: Outer Top Cover Plate DSC: Dry Shielded Canister DWH: Horizontal Dead Weight PI : Internal Pressure Fweld : Resultant weld load (excluding compressive load)
R: Radius of OTCP /ITCP weld Tweld : Weld size Weld Stress: The weld stress for the OTCP and ITCP a',, : Weld membrane stress at limit load for OTCP and ITCP SRSS: Square root of sum of squares.
7.0 COMPUTATIONS 7.1 OTCP Weld for Reduced Weld Size Evaluation The primary stress controlling load combinations for the OTCP are listed in Ref. ([5.2], Table 52). For all the primary loads the weld is modelled as a line weld with no bending moment passing through. Hence, the weld stresses are scaled by a ratio of weld throat sizes (0.50"/0.48")=1.042. These stresses are listed in Table 1.
The secondary stress controlling load combinations for the OTCP are listed in Ref. ([5.2], Table 53). The three components of the secondary stress are membrane (Pm), bending (Pb) and thermal stress (Q). The reduction in weld size would increase the Pm by 1.042 and the bending by (1.0422 = 1.085). The thermal stress would tend to reduce with the reduction in stiffness. However, conservatively the entire secondary stresses at the weld are scaled by a ratio of 1.085. These stresses are listed in Table 2.
Calculation No. 11042-0204 Revision No. 2 AREVA Calculation Page 8of 15 7.2 Allowable Flaw Size Evaluation 7.2.1 Weld Post-Processing and Stress Calculation Proprietary Information Withheld Pursuant to 10 CFR 2.390 7.2.2 Determination of Allowable Weld Flaw Size Proprietary Information Withheld Pursuant to 10 CFR 2.390
Calculation No. 11042-0204 Revision No. 2 AR EVA Calculation Page 9of 15 a) OTCP Allowable Weld Flaw Proprietary Information Withheld Pursuant to 10 CFR 2.390 ITCP Allowable Weld Flaw Proprietary Information Withheld Pursuant to 10 CFR 2.390 8.0 RESULTS The OTCP weld stresses for the reduced weld size are listed in Table 1 and Table 2. The maximum stress ratio for all the service level A, B C and D for the OTCP weld is 0.85.
The OTCP and ITPC closure welds for individual and combination load cases are listed in Table 4 through Table 7. The allowable flaw for surface and subsurface flaws for OTCP and ITCP are listed below.
OTCP Surface/ Subsurface Crack: 0.27 inch and 3600 along the circumference ITCP Surface/ Subsurface Crack: 0.10 inch and 3600 along the circumference
9.0 CONCLUSION
S The DSC stress evaluation show that the reduced weld size of 0.48" for the OTCP will have no adverse effect on the design functions of the DSC. All the component stresses remain below the stress allowable limits. The evaluations performed in this calculation indicate that the minimum allowable flaw size for the OTCP and ITCP is 0.27" and 0.10" for a full 360' weld flaw, respectively.
Calculation No. 11042-0204 Revision No. 2 AREVA Calculation Page 10 of 15 10.0 LISTING OF FILES Proprietary Information Withheld Pursuant to 10 CFR 2.390
Calculation No. 11042-0204 Revision No. 2 AREVA Calculation Page 11 of 15 Table 1 Controlling Load Combinations Stress Results for the non-compliant OTCP Closure Weld (Primary Stress) 0.48" Weld Allowable Load Service Stress Loads 0.5' Weld Stress (1) Stress (2) Stress Case Level Category Stress (ksi) (ksi) (ksi) Ratio TL-2 A P DWV + PI(10) 0.64 0.67 12.3 0.06 TL-3 A P DWH +PI(10) 1.86 1.94 12.7 0.16 TL-4 A P DWH + PI(10) 1.86 1.94 12.3 0.16 TR-1 A P DWH + PI(10)+1gAxial 2.01 2.09 12.7 0.17 TR-2 A P DWH + PI(10) + lg Trans. 2.37 2.47 12.7 0.20 TR-3 A P DWH + PI(10) + lg Vert. 3.10 3.23 12.7 0.27 TR-4 A P DWH + PI(10) + 0.5g X,Y,Z 2.66 2.77 12.7 0.23 TR-5 A P DWH + PI(10) + ig Axia, 2.01 2.09 12.3 0.18 TR-6 A P DWH + P1(10) + 1g Trans. 2.37 2.47 12.3 0.21 TR-7 A P DWH + PI(10) + lg Vert. 3.10 3.23 12.3 0.27 TR-8 A P DWH + PI(10) + 0.5g XY,Z 2.66 2.77 12.3 0.23 TR-9 D P P1(20) + 25g Corner Drop 23.00 23.97 32.4 0.74 TR-1 1 D P P1(20) + 75g BED 0.36 0.38 29.4 0.01 TR-10 D P PI(20) + 75g SD 11.40 11.88 31.1 0.40 HSM-3 B P DWH + PI(10) 1.86 1.94 13.1 0.15 HSM-4 C P DWH +P1(20) 2.45 2.55 15.7 0.17 HSM-6 D P DWH + PI(65) 4.75 4.95 27.2 0.19 HSM-8 C P DWH + P1(20) Seismic 8.30 4 8.65 15.7 0.57 HSM-10 C P DWH +Flood 1.38 1.44 15.7 0.10 Notes 1: Weld stress for 0.48" weld are calculated by scaling the weld stress of 0.5" by a factor of 1.042 2: The allowable stresses are taken at the highest temperature for each load combination consistent with the Ref. [5.2].
Table 2 Controlling Load Combinations Stress Results for the non-compliant OTCP Closure Weld (Secondary Stress) 0.5" Weld 0.48" Weld
() Allowable Load Service Stress Loads Stress Stress (1) Stress (2) Stress Case Level Category Intensity Intensity (ks' Ratio (ksi) (ksi)
TL-2 A PL+Pb+Q DWV + PI(10) + TH19 19.40 21.05 36.8 0.57 TL-3 A PL+Pb+Q DWH +PI(10)+TH1 27.96 30.34 38.1 0.80 TL-4 A PL+Pb+Q DWH + P1(10) + TH2 27.96 30.34 36.8 0.82 TR-1 A PL+Pb+Q DWH + PI(10) + 1g Axial + TH1 28.32 30.73 38.1 0.81 TR-2 A PL+Pb+Q DWH + PI(10) + 1g Trans + TH1 28.35 30.77 38.1 0.81 TR-3 A PL+Pb+Q DWH + PI(10) + lg Vert. + TH1 28.91 31.37 38.1 0.82 TR-4 A PL+Pb+Q DWH + PI(10) + 0.5g X,Y,Z + TH1 28.69 31.13 38.1 0.82 TR-5 A PL+Pb+Q DWH + P1(10) + 1g Axial + TH2 28.32 30.73 36.8 0.84 TR-6 A PL+Pb+Q DWH + P1(10) + 1g Trans + TH2 28.35 30.77 36.8 0.84 TR-7 A PL+Pb+Q DWH + PI(10) + lg Vert. + TH2 28.91 31.37 36.8 0.85 TR-8 A PL+Pb+Q DWH + PI(10) + 0.5g X,Y,Z + TH2 28.69 31.13 36.8 0.85 HSM-3 B PL+Pb+Q DWH + PI(10) + TH13,14,25 25.56 27.74 40.7 0.68 Note 1: Weld stress for 0.48" weld are calculated by scaling the weld stress of 0.5" by a factor of (1.042) = 1.085 2: The allowable stresses are taken at the highest temperature for each load combination consistent with the Ref.
[5.2].
Calculation No. 11042-0204 Revision No. 2 AR EVA Calculation Page 12 of 15 Table 3 Safety Factors for Circumferential Flaw (Ref. [5.1])
Circumferential Flaws Service Membrane Stress Level SFm A 2.7 B 2.4 C 1.8 D 1.3
Calculation No. 11042-0204 Revision No. 2 A R EVA Calculation Page 13 of 15 Proprietary Information Withheld Pursuant to 10 CFR 2.390
Calculation No. 11042-0204 Revision No. 2 AREVA Calculation Page 14 of 15 Proprietary Information Withheld Pursuant to 10 CFR 2.390
Calculation No. 11042-0204 Revision No. 2 AR EVA Calculation Page 15 of 15 Proprietary Information Withheld Pursuant to 10 CFR 2.390
L-MT-14-016 ENCLOSURE 4 AFFIDAVIT FOR WITHHOLDING PROPRIETARY DOCUMENTS 1 page follows
AREVA Inc. E-38790 AFFIDAVIT PURSUANT TO I0 CFR 2.390 AREVA, Inc. )
County of Howard )
I, Paul Triska, depose and say that I am a Vice President of AREVA Inc., duly authorized to execute this affidavit, and have reviewed or caused to have reviewed the information which is identified as proprietary and referenced in the paragraph immediately below.J. am submitting this affidavit in conformance with the provisions of 10 CFR 2.390 of the regulations for withholding this information.
The information for which proprietary treatment is sought 'is described below, The calculation listed is intended to be submitted to the United States Nuclear Regulatory Commission in conjunction with an exemption request from Xcel Energy:
o Calculation No. 11042-0204 Revision 2, 7Structural and Allowable Flaw Size Evaluation of the Spent Fuel Storage Canisters with Nonconforming Closure Welds at Monticello Nuclear Generating Plant" This document has been appropriately designated as proprietary.
I have personal knowledge of the criteria and procedures utilized by AREVA Inc. in .designating information as -a trade secret, privileged or as confidential commercial or financial information.
Pursuant to the provisions of paragraph (b) (4) of Section 2,390 of the regulations, the following is furnished for consideration in determining whether the information sought to be withheld from public disclosure, included in the abovc rcfercnccd document, should bc withheld.
- 1) The information sought to be withheld .from public disclosure involves calculation details associated with structural analysis of a spent nuclear fuel dry storage system, which are owned and have been held in confidence by AREVA Inc.
- 2) The information is of a type customarily held in confidence by AREVA Inc. and not customarily disclosed to.die public. AREVA Inc. has a rational basis for determining the typesof information customarily held in confidence.
- 3) Public disclosure of the information is likely .to cause* substantial harm to the competitive position of AREVA Inc. because the information is related to calculation details associated with structural analysis of a spent nuclear fuel dry storage system, the application of which provides a competitive economic advantage.
The availability of such informati.on to competitors would enable them to modify their product to better compete with AREVA Inc.., take marketing or other actions to .[mprove their product's position or impair the position of AREVA Inc.'s product, and avoid developing similar data and analyses in support of their processes, methods or apparatus.
Further the deponent sayeth not.
Paul Triska Vice President, AREVA Inc.
bed and sworn to me before this 9th day of July 2014.
Notary Public /aO19 t ol.
My Commission Expires Ii /1) /* Ol 1-tgWUmCOft, MO, M*omutnE2,.Ny.1,9 Page IPof I