Text

Diablo Canyon, Unit 2 - Relief Request SWOL-REP-1-U2: Submittal of Revised Areva Calculations. Part 2 of 15
	ML14259A298
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Site:	Diablo Canyon
Issue date:	09/15/2014
From:	; AREVA
To:	; Office of Nuclear Reactor Regulation
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	DCL-14-084 32-9221080-003, 32-9221082-003
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Document A AREVA Document No. 32-9221080-003 Diablo Canyon Unit 2 Pressurizer Safety/Relief Nozzles Laminar/Planar Flaw Analysis-NonProprietary Name Size Date/Time Modified CRC DC2 TRT fr NewPath SY.out --7600 May 07 2014 13:31:1929317 DC2 TRT fr NewPath SZ.out 7600 May 07 2014 13:31:19 51916 DC2 TRT fr NewPath Sh.out 7600 May 07 2014 13:31:19 53650 DC2 TRT fr NewPath TH.out 7600 May 07 2014 13:31:19 09806 DC2_fr_new_path.out 2730565 May 07 2014 13:31:25 47666 vm56.out 63001 May 07 2014 15:39:48 56221 vm56.vrt 593 May 07 2014 15:39:48 40729 Page 54 Controlled Document A AREVA Document No. 32-9221080-003 Diablo Canyon .Unit 2 Pressurizer Safety/Relief Nozzles Laminar/Planar Flaw Analysis-NonProprietary APPENDIX 8: WELD RESIDUAL STRESSES FOR SAFETY NOZZLE WOL FRACTURE MECHANICS ANALYSIS FOR OUTAGE 2R17 8.1 Purposes The purpose of this appendix is to summarize residual stresses to support flaw evaluations with NDE measurement uncertainty of the indications detected or* assumed to exist based on the results of the 2013 seventeenth refueling outage (2R17) inservice inspection.

Only indications that are considered rejectable in the overlaid Pressurizer (PZR) Safety Nozzles of Diablo Canyon Power Plant (DCPP) Unit 2 are considered.

The indications are reported in Reference

[B 1]. Results are provided along path lines that are located in close proximity to the found laminar indications in the Safety /Relief nozzle. 8.2 Methodology This appendix provided only post processing of the database that was developed in Reference

[B3]. Path lines for obtaining the residual stresses were selected to best match the locations and sizes of the flaw indications as described in Reference

[B 1]. It should be noted that since the finite element is discrete and it does not exactly match the sketches of the Safety Nozzles provided in Reference

[B 1 ], the selected path lines locations and sizes are only a best estimate representation of the indications locations and sizes. The interfacial/

horizontal path lines are used to sample stresses to be used for evaluating a laminar flaw. Thus radial and shear stresses are of interest for the interfacial/

horizontal path line. The path lines investigated in this appendix are illustrated in Figure B-1. Figure 8-1: Safety Nozzles Path lines A_wol, A_noz, A_all Page 55 Controlled Document A AREVA Document No. 32-9221080-003 Diablo Canyon Unit 2 Pressurizer Safety/Relief Nozzles Laminar/Planar Flaw Analysis-NonProprietary 8.3 Results Axial (SY), hoop (SZ), radial (SX), and shear (SXY) stresses are read from the database and the result files that were archived in the weld residual stress document [B3]. To ensure that the stress sampling results in the most bounding stresses for the path lines located near the interface of the overlay and the original material (nozzle), the post processing for the interfacial path lines was processed while selecting either the overlay (WOL) material, the nozzle (NOZ) material, or both materials.

8.3.1 Interfacial Pathlines Results The interfacial path lines are of interest for evaluating laminar flaws. Thus, only the radial and shear stresses are of interest.

As discussed before, for all interfacial path lines (except for Safety Nozzle C Interfacial Pathline 2, which is located entirely in the overlay), three post processing runs were performed by either selecting all materials, overlay material, or nozzle material.

The results are documented in output files "SafetyRellief_pathsALL.out", "SafetyRellief_pathsOL.out", and "SafetyRellief_pathsBASE.out".

The results from the output files are manipulated in file "Results.xlsm" to select the most bounding stresses.

The minimum and maximum values of the radial and shear stresses are tabulated in Table B-1. Table B-1: Bounding Radial and Shear Stresses for Interfacial Path lines Nozzle Path line Radial Stress (psi) Shear Stress (psi) Minimum Maximum Minimum Maximum Safety Nozzle A [ ] [ ] [

] [ ] (A_wol, A_noz, A_all) Safety Nozzle B [ ] [ ] [ ] [ ] (B_wol, B_noz, B_all) Safety Nozzle C2 (C2_wol, C2_noz, [ ] [ ] [ ] [ ]

C2 all) 8.4 Computer Usage 8.4.1 Software and Hardware ANSYS Version 14.5.7 [B2] was used in this calculation.

Verification test cases were perfonned and documented herein.

Computer program tested: ANSYS Version 14.5.7, verification tests vm32mod2D.vrt and vm38mod2D,vrt.

Error notices for ANSYS Version 14.5.7 were reviewed and none apply for this analysis.

Computer hardware used: The computer hardware used in the analysis is DELL (Service Tag # 5VKW5S1).

The hardware platform is Intel CoreŽ i7-2640M CPU@ 2.8 GHz, 8GB RAM and operating system is Microsoft Windows 7 Enterprise x 64 Edition, Version 2009, and Service Pack 1.

Name of person running the test: Silvester Noronha

Date oftest: 04-10-2014 Page 56 Controlled Document A AREV.A Document No. 32-9221080-003 Diablo Canyon Unit 2 Pressurizer Safety/Relief Nozzles Laminar/Planar Flaw Analysis-NonProprietary

Acceptability:

For ANSYS 14.5.7 cases vm32mod2D, vm38mod2D were run to verify that the answers are correct. The files vm32mod2D.vrt and vm38mod2D.vrt contain output from the test cases. Review of the output shows that the results are acceptable.

8.4.2 Computer Files All ANSYS input/output files are listed in Table B-:2. Pertinent files are documented in the ColdStor storage path "\cold\General-Access\32\32-9000000\32-9215965-002\official\WRS".

Table B-2: Computer Files Name Size Date/Time Modified CRC PostProcessSafetyAll.inp 4250 May 09 20l4 14:32:31 25988 PostProcessSafetyAll.out 30085 May 09 2014 14:32:57 25595 PostProcessSafetyBase.inp 4259 May 09 2014 14:35:43 35199 PostProcessSafetyBase.out 30391 May 09 2014 14:36:13 05068 PostProcessSafetyOL.inp 4244 May 09 2014 14:26:19 62041 PostProcessSafetyOL.out 30351 May 09 2014 14:27:06 45557 Results.xlsm 55415 May 09 2014 14:39:28 26487 SafetyRellief_pathsALL.out 17219 May 09 2014 14:32:57 46681 SafetyRellief_pathsBASE.out17222 May 09 2014 14:36:13 60937 SafetyRellief_pathsOL.out 17215 May 09 2014 14:27:06 53535 vm32mod2D.vrt 624 Apr 10 2014 08:33:44 17780 vm38mod2D.vrt 650 Apr 10 2014 08:30:40 36343 8.5 References Bl. AREVA Document 38-9200149-001, (DCPP Unit 2 DIT-50540188-04-00), "DCPP Unit 2 Pressurizer Nozzle NDE Data" B2. ANSYS Finite Element Computer Code, Version 14.5.7, ANSYS Inc., Canonsburg, PA B3. AREVA Document 32-9049062-006, "Diablo Canyon Unit 2 Pressurizer Safety/ReliefNozzle Weld Overlay Residual Stress Analysis" Page 57 Controlled Document A AREVA Document No. 32-9221080-003 Diablo Canyon Unit 2 Pressurizer Safety/Relief Nozzles Laminar/Planar Flaw Analysis-NonProprietary APPENDIX C: FLAW SIZE UNCERTAINTY CONSIDERATION This appendix contains sensitivity analysis to account for NDE uncertainty in flaw size measurement.

The NDE uncertainty was estimated in Reference

[C1] to be +/-0.125 in. on either side or 0.25 in. total for the axial dimension of the laminar flaws. Incrementing the detected flaw size by 0.25 in, the flaw sizes to be used for flaw evaluation becomes 0.65 in. for the indications in Nozzle A and 0.50 in. for the indications in Nozzle B and Nozzle C. Using the updated flaw sizes, the crack growth analyses were performed following the procedure outlined in the main body of the document.

The calculations presented in this appendix used the operating stresses obtained in Appendix A and the residual stresses obtained in Appendix B. The flaw growth evaluations were performed considering the design transients for the 38-year design life of the weld overlays.

The results of the flaw growth analyses are tabulated in Table C-1. Note that unlike the zero crack growth reported in the calculation in main body of this document, crack case FLB_noz grew [ ] in this case. Table C-1: Results of Flaw Growth Analysis with [0.25] in NDE Uncertainty Indication Case Initial Crack Final Crack Growth (in.) Crack Size (in.) Size (in.) Increase(%)

FLA_wol 0.65 0.650202453 0.000202453 0.031 A-#1, #1A FLA_noz 0.65 0.650380104 0.000380104 0.058 FLB_wol 0.5 0.502052237 0.002052237 0.410 B-#1' #2 & #3 FLB_noz 0.5 0.502999419 0.002999419 0.600 c -#4 FLC2_wol 0.5 0.500046687

0. 000046687 0.009 The flaw area calculations are presented in Table C-2 and are based on increasing the width of the indications by 0.25 in. to account for NDE sizing uncertainty.

Based on these area calculations, it is shown in Table C-2, that the laminar flaw indications in Nozzle B and Nozzle C (FLB and FLC2) meet the acceptance standards in article IWB-3514.6 of Section XI [2] after 38 years of operation.

, Indications in Nozzle A exceeds the allowable area limit of 7.5 in.2 (7.9555 in 2 > 7.5 in 2) for this assessment.

Page 58 Controlled Document A AREVA Document No. 32-9221080-003 Diablo Canyon Unit 2 Pressurizer Safety/Relief Nozzles Laminar/Planar Flaw Analysis-NonProprietary Table C-2: Laminar Area Evaluation with [0.25] in NDE Uncertainty FLA FLB FLC2 Reference

/Comments Initial flaw width, Winitial (in.) 0.65 0.5 0.5 Table C-1 Final flaw width, Wtinal (in.) 0.65038010 0.50299942 0.50004669 Table 7-5 Initial flaw length, /initial (in.) 16.3 4.7 2.0 References

[4] and [1] Final flaw length, /final = 16.30953183 4.72819453 2.00018675 See Note (1) (Wfinatf Winitial ) !initial (in.) below Acal = 0. 75(Wtinal X lfinaJ (in 2) 7.9555(2) 1.7837 0.7501 Section 2.1.3 Alimit (in 2) 7.5 7.5 7.5 Table IWB-3514-3 of [2] Check Acal =:;; Alimit Not Met OK OK Note (1 ): Geometrically similar flaw growth is assumed in the growth analysis.

This assumption maintains a constant aspect ratio as defined by the initial flaw, winitiallinit i at* The final flaw length, lnnat was computed based on Wnnat determined in the growth analysis.

The assumption of geometric flaw shape in the growth analysis is conservative since the cyclic stresses acting at the flaw plane are taken as uniform stress over the flaw area. Under uniform stress conditions, the flaw aspect ratio will decrease during the growth making the lnnat smaller than that computed by the constant aspect ratio assumption.

(2) : Note that this value is more than the area limit (7.5 in 2 ). However, on further analytical evaluation as permitted by IWB-3132.3

[2], it is found to be acceptable as shown below. To assess the significance of not meeting the NDE acceptance standards of IWB-3514.6 (Table IWB-3514-3), flaw acceptance was evaluated by analysis.

Flaw acceptance by analytical evaluation is permitted by IWB-3132.3

[3] when acceptance standards are exceeded.

In this application, the analytical evaluation is based on Section Ill design rules to establish the allowable overlay weld length. The minimum required overlay length evaluation is summarized in Table C-3 where the effective overlay length (Leff) is evaluated as the actual overlay length (Lwa 1) minus the flaw length (Lt 1 aw). As seen in seen in Table C-3, the overlay minimum length requirement is still satisfied for all flaws. For the indications in Nozzle A (FLA) the overlay minimum required length (Lreq) is [ ] in., which is less than the effective overlay length (Lert) of [ ] in. For indications in Nozzle B (FLB) and Nozzle C (FLC2), the overlay minimum required length (Lreq) is [ * ] in. and [ ], which are less than the effective overlay length (Lert) of [ ] in. and [ ] in., respectively.

Thus it is concluded that the laminar indications in all three safety/relief nozzles (Nozzle A, Nozzle B and Nozzle C) will not impact the integrity of the overlay for 38 years of plant operation.

Page 59 Cont ra Document A AREVA Document No. 32-9221080-003 Diablo Canyon Unit 2 Pressurizer Safety/Relief Nozzles Laminar/Planar Flaw Analysis-NonProprietary Table C-3: Overlay Length Evaluation with [0.25] in NDE Uncertainty Parameter FLA FLB FLC2 Reference/Comments Lreq = <1net t f 0.6Sm (in) [ [ ] [ ] Table 7-7 Lwol (in) [ J1) [ J1) [ J2) See notes below Lflaw (in) 0.6504 0.5030 0.5000 Table C-1 Leff = Lwol -Ltlaw (in) [ ] [ ] [ ] Check Leff > Lreq OK OK OK (1). Note . Per the des1gn draw1ng the d1stance from the end of butter to the end of overlay at the nozzle should be at least [ ] [11]. Note this value is higher than the overlay length of [ ] used in Table 7-7, which was conservatively estimated using minimum design configuration in Reference

[11]. (Z): From Reference

[11] [ ] Conclusions The analysis presented above confirms that the SWOL with postulated flaws accounting for an NDE measurement uncertainty of +/-0.125 in. on either side or 0.25 in. total for the axial dimension of the laminar flaws still meets the overlay length requirement per NB-3227.2[3]

in all three Safety/Relief Nozzles. Thus, it is concluded that the laminar indications in all three nozzles will not impact the integrity of the SWOL for 38 years o"f plant operation.

Computer Files Mathcad and Excel spreadsheets are used in this calculation.

The hardware platform (Service Tag# 5VKW5S1) is Intel CoreŽ i7-2640M CPU 2.80 GHz, 8.00 GB RAM. The operating system is Microsoft Windows 7 Enterprise, Copyright© 2009, Service Pack 1. All computer files are listed in this section. All files are available in AREVA Inc. ColdStor storage \\cold\Generai-Access\32\32-9000000\32-9215965-002\officiai\CGA.

Name Laminar Flaws UC.xmcd --LaminarFlawsUC.xlsx References Table C-4: Computer Files Size 913977 312787 Date/Time Modified May 16 2014 15:50:20 May 19 2014 11:26:32 CRC 16443 49133 C1. AREVA Document 38-9223975-000 "DCPP2-NDE Measurement Uncertainty Information" Page 60 Controiled Document 0402-01-F01 (Rev. 018, 01/30/2014)

A AREVA CALCULATION

SUMMARY

SHEET (CSS) Document No. 32 9221082 003 Safety Related:

D No ----------------------------------------

Title Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary PURPOSE AND

SUMMARY

OF RESULTS: Purpose An inservice inspection of Diablo Canyon Power Plant (DCPP) Unit 2 overlaid Pressurizer (PZR) Spray nozzle revealed the existence of indications.

The indicat i ons are described in the Diablo Canyon Power Plant Design Input Transmittal (DIT) summarized in Reference

[1]. Previous disposition of all reported laminar indications per the rules of the acceptance standards Table IWB-3514-3 of ASME B&PV Code Section XI [2] and Section Ill [3] are reported in Reference

[4]. The purpose of this document is to validate that the acceptance standards under IWB-3500 remain valid after any potential crack growth. All indications observed in the PZR Spray nozzle are laminar. This document analyzes the indications for the remaining 38 years of plant operation.

The indications are all embedded within the body of the nozzle and weld overlay. Therefore , no primary water stress corrosion crack growth mechanism would occur. The only mechanism by which indications could grow is fatigue crack growth. This document provides a description of the indications, postulated flaws, applicable fatigue crack growth laws, fatigue crack growth analysis, and finally the predicted final flaw sizes are evaluated in accordance with the rules of ASME B&PV Code Section XI [2] and Section Ill [3]. Reference

[5] Section 4.6, item 3 states that the applicable ASME code , year is 2004 with addenda through 2005. Proprietary information is contained within bold square brackets"[ ]". Westinghouse proprietary information is contained within blue boxes. The purpose of Revision 003 is to update proprietary markings.

Non-Proprietary document for 32-9213780-004 Summary of Results The final crack sizes for all path cases are summarized in Table 7-5. The flaw area evaluation and overlay length evaluation a r e performed in Table 7-6 and Table 7-7, respectively.

It is concluded that the laminar flaws meet the acceptance standards of Section XI of the ASME Code [2] for the remaining 38 years of plant operation.

Measurement uncertainty is addressed in Appendix A. It is concluded in Appendix A that the laminar indications, including Indications 1 and 4 (Group 1) will not impact the integrity of the SWOL for 38 years of plant operation.

Results and conclusions from Revision 002 remain valid. THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: CODENERSION/REV CODENERSION/REV None THE DOCUMENT CONTAINS ASSUMPTIONS THAT SHALL BE VERIFIED PRIOR TO USE DYes Page 1 of 52 Controlled Document A .AREV.A 0402-01-F01 (Rev. 018, 01/30/2014)

Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Review Method: ISJ Design Review (Detailed Check) D Alternate Calculation Signature Block P/R/A Name and Title and (printed or typed) Signature LP/LR Date Samer H Mahmoud I p

\Y Principal Engineer Tom Riordan 12SEP2014 R Engineer III Tim M Wiger A 1{71</ Engineering Manager L/ Note: P/R/ A designates Preparer (P), Reviewer (R), Approver (A); LP/LR designates Lead Preparer (LP), Lead Reviewer (LR) Pages/Sections Prepared/Reviewed/Approved All. All. All. Project Manager Approval of Customer References (N/A if not applicable}

Name Title (printed or typed) (printed or typed) Signature Date N/A NIA NIA N/A Mentoring Information (not required per 0402-01} Name Title Mentor to: (printed or typed) (printed or typed) (P/R) Signature Date NIA NIA N/A N!A N/A Page 2 A. AREVA Revision No. 000 001 002 003 Controlled Document 0402-01-F01 (Rev. 018, 01/30/2014)

Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Record of Revision Pages/Sections/Paragraphs Changed Brief Description I Change Authorization All Original Release Page 1 Added purpose and summary for Revision 002 Section 5.0 Listed new file Appendix A Added Appendix A css Added purpose for revision Throughout Removed proprietary markings of material names and indication descriptions Section 8 Updated References Throughout Proprietary markings updated Section 8 Updated References Page 51 Corrected overlay minimum required length for indications 1 and4. Non-Proprietary document for 32-9213780-004 Page 3 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table of Contents Page SIGNATURE BLOCK ................................................................................................................................

2 RECORD OF REVISION ..........................................................................................................................

3 LIST OF TABLES .....................................................................................................................................

6 LIST OF FIGURES ...................................................................................................................................

7

1.0 INTRODUCTION

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8 2.0 ANALYTICAL METHODOLOGY

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9 2.1 Stress Intensity Factor Model ........................

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.................. 9 2.2 Fatigue Crack Growth Calculation

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11 2.3 Laminar Flaw Evaluation

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11 2.4 Minimum Required Overlay Length Calculations

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12 2.5 List of Abbreviations and Parameters

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13 3.0 ASSUMPTIONS

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15 3.1 Unverified Assumptions

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15 3.2 Justified Assumptions

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15 3.3 Modeling Simplifications

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15 4.0 DESIGN INPUTS ............................................................................

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16 4.1 Geometry ........................................................................................................................................

16 4.2 Material .............................................................................................

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20 4.3 External Loads ...............................................................................................................................

20 4.4 Operating Transients

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22 4.5 Operating Stresses ......................

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23 4.6 Operating Temperatures

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27 4.7 Residual Stresses ............

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27 4.8 Fatigue Crack Growth Laws ......................

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28 4.8.1 Alloy 52 and 52M (FSWOL) ....................

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............................................. 28 4.8.2 Stainless Steel (308 SS Weld) ...........................................

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29 4.8.3 Low-Alloy Steel (SA-508) ...............

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30 Page4 ControUed Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table of Contents (continued)

Page 5.0 COMPUTER USAGE ..................................................................................................................

32 5.1 Software and Hardware ...............................................................

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32 5.2 Computer Files .................................................................................

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32 6.0 CALCULATIONS

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33 6.1 Alloy 52M (Weld Overlay) ......................

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33 6.2 Stainless Steel (Pipe to Safe End Weld) ........................................................................................

34 6.3 Low-Alloy Steel (SA 508 Nozzle Material)

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36 7.0 RESULTS ...............

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37 7.1 Fatigue Crack Growth ....................................................................................................................

37 7.2 Laminar Flaw Evaluation

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45

8.0 REFERENCES

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48 APPENDIX A: FLAW SIZE UNCERTAINTY CONSIDERATION

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50 Page 5 Contro ne d Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary List of Tables Page Table 4-1: Spray Nozzle Dimensions

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16 Table 4-2: Dimensions for SIF Calculation

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18 Table 4-3: Table of Materials

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20 Table 4-4: PZR Spray Nozzle Sustained and Seismic Loading Conditions at Safe End Applicable to Crack Growth Analysis .....................................................................................................................

21 Table 4-5: PZR Spray Nozzle Sustained and Seismic Loading Conditions at Nozzle Applicable to Crack Growth Analysis .....................................................................................................................

21 Table 4-6: PZR Spray Nozzle Sustained and Seismic Loading Conditions at Safe End Applicable to Overlay Sizing ...................................................................................................................................

21 Table 4-7: PZR Spray Nozzle Sustained and Seismic Loading Conditions at Nozzle Applicable to Overlay Sizing ... : .....................................

Table 4-8: Operating Transients for PZR Spray Nozzle [7] ...................................................................

22 Table 4-9: Maximum and Minimum Stresses for Indications 1 and 4 (Path line Fline2) .........................

25 Table 4-10: Maximum and Minimum Stresses for Indications 2 and 3 (Pathline Fline4) .......................

26 Table 4-11: Maximum Temperatures for Path Line Cases (Units: °F) ...................................................

27 . Table 4-12: Bounding Radial and Shear Weld Residual Stresses for Laminar Flaws ...........................

28 Table 5-1: Computer Files .....................................................................................................................

32 Table 7-1: Fatigue Crack Growth for Indications 1 and 4 (Case FL2_wol) ............................................

37 Table 7-2: Fatigue Crack Growth for Indications 1 and 4 (Case FL2_noz) ............................................

39 Table 7-3: Fatigue Crack Growth for Indications 2 and 3 (Case FL4_wol) ............................................

41 Table 7-4: Fatigue Crack Growth for Indications 2 and 3 (FL4_wld)

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.43 Table 7-5: Summary of Fatigue Crack Growth .....................................................................................

.45 Table 7-6: Flaw Area Evaluation

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.46 Table 7-7: Overlay Length Evaluation

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.47 Table A-1: Results of Flaw Growth Analysis with 0.25 in NDE Uncertainty

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50 Table A-2: Laminar Area Evaluation with 0.25 in NDE Uncertainty

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51 Table A-3: Overlay Length Evaluation with 0.25 in NDE Uncertainty

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52 Page , 6 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary List of Figures Page Figure 2-1: A Through-Wall Crack in the Center of a Plate ...................................................................

10 Figure 4-1: Schematic of the Spray Nozzle with FSWOL ......................................................................

16 Figure 4-2: WIB-345 Overlay Rollout Spray Nozzle (Ref. [1]) ................................................................

17 Figure 4-3: Spray Nozzle WIB-345 Overlay Indication Plot (Ref. [1]) ....................................................

17 Figure 4-4: Idealization of the CCP Model for the Spray Nozzle Indications

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19 Figure 4-5: PZR Spray Nozzle with Path Lines Superposed

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24 Page 7 Control!ed Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary

1.0 INTRODUCTION

An inservice inspection of Diablo Canyon Power Plant (DCPP) Unit 2 overlaid Pressurizer (PZR) Spray nozzle revealed the existence of indications.

The indications are described in the Diablo Canyon Power Plant Design Input Transmittal (DIT) documented in Reference

[1 ]. All indications found in the PZR Spray nozzle are laminar. Previous disposition of the as found laminar indications per the rules of the acceptance standards in Table IWB-3514-3 of the ASME B&PV Code Section XI [2] and Article NB-3227.2 of ASME B&PV Code Section Ill [3] are documented in Reference

[4]. Reference

[4] did not consider any potential flaw growth that may occur due to sustained and cyclic operating conditions.

The purpose of this document is to assess the flaw growth that could take place for the remaining 38 years of plant operation.

Because the laminar indications are located between the overlay and the original underlying materials, the surfaces of the indications do not come in contact with the reactor coolant. Therefore, no primary water stress corrosion crack (PWSCC) growth mechanism would occur. The only credible mechanism by which the indications could grow is fatigue crack growth. This document provides a description of the indications, postulated flaws, applicable fatigue crack growth laws, fatigue crack growth analysis, and finally the predicted final flaw sizes are evaluated in accordance with the rules of ASME B&PV Code Section XI [2] and Section Ill [3]. Reference

[5] Section 4.6, item 3 states that the applicable ASME code year is 2004 with addenda through 2005. Page 8 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary 2.0 ANALYTICAL METHODOLOGY This document performs flaw evaluation for dispositioning the NDE found indication in the DCPP PZR Spray nozzle. As described in Reference

[1 ], all indications were laminar in nature. Thus, this document postulates cylindrical flaws to analyze all laminar indication.

For each postulated flaw, the flaw evaluation methodology consists of performing fatigue flaw growth for the specified service life. At the end of life, a flaw evaluation is performed to evaluate the end of life flaw acceptability.

This analysis postulated cylindrical sub-surface flaws, which could propagate by fatigue crack growth through the body of the Spray nozzle and full structural weld overlay (FSWOL). A linear elastic fracture mechanics (LEFM) analysis was performed to determine the applied stress intensity factors (SIFs) for the laminar flaw indications.

The center-cracked panel (CCP) model was used with the radial and shear stresses to compute stress intensity factors for the laminar flaw indications.

Flaw growth in the axial direction to estimate final flaw width was calculated using the SIF from the CCP model. Circumferential crack growth for estimating the final flaw length was evaluated by extending the flaw length in proportion to the ratio of final flaw width to the initial flaw width. It should be noted that the planar flaw analysis for DCPP Unit 2 PZR nozzles [6] used 38 years of remaining service life. The current analysis was performed using the 38 years of remaining service life as well. The crack growth analysis considered the growth of embedded flaws due to cyclic loadings under the presence of residual stress from the welding processes.

The final flaw sizes were calculated using the same operating transients considered in the original 2007 flaw growth analysis [7]. The predicted final flaw sizes were evaluated in accordance with the rules of ASME B&PV Code Section XI Table IWB-3514-3

[2]. Using Section Ill article NB-3227.2

[3], the presence of the laminar flaws was evaluated to assess the ability of the weld overlay to perform its intended function.

Section Ill article NB-3227.2

[3] was used to verify that the weld overlay length excluding the indications is sufficient to transfer the load through shear back to the base metal considering a 100% through wall crack in the PWSCC susceptible material.

The initial structural overlay analysis was performed in 2007 per ASME Section Ill Subsection NB Code with 2001 and 2003 Addenda. During relief request of 2013, the shear stress check for the laminar flaw analysis was performed per ASME Section Ill Subsection NB Code with 2004 and 2005 Addenda. Both Code years were reviewed and it was determined that the criteria for pure shear stress evaluation per NB-3227.2 are the same. Hence, it is concluded that both the Codes are applicable to the current analyses and no additional reconciliation is required.

The remainder of this section describes the model used to calculate the stress intensity factor (SIF), crack growth calculation procedure, flaw evaluation, FSWOL minimum length requirement evaluation, and a list of the abbreviations and parameters used throughout the document.

2.1 Stress Intensity Factor Model To calculate the stress intensity factor for the laminar flaw, the closed-form SIF solution from page 40 of Reference

[8] for CCP model was used. The Mode I and Mode II configurations are illustrated in Figure 2-1. Page 9 Co trolled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary (Mode I) (Mode II) Figure 2-1: A Through-Wall Crack in the Center of a Plate For Mode I configuration, the K 1 solution is listed below: K 1 =

F0i) F0i)= [ 1-o.o2s0iJ + o.o60i}

Where, a= uniform tensile stress 2a = crack length 2b =plate width For Mode II configuration, the K 11 solution is identical to the Mode I solution except using '"C (uniform shear stress) instead of a (uniform tensile stress). It should be noted that some geometry idealization was made to use the CCP model SIF solution to analyze the Spray nozzle laminar indications.

More discussion about the geometry idealization is provided in Section 4.1. The functions F(alb) is a geometry correction factor in which the b parameter accounts for the free surface effects. For an alb value of 0, F(0)=1 and for an alb value of 1, the geometry correction factor F(alb) asymptotically approaches a very large value. For an alb value of 99.9%, F(0.999) = 26.1. The selection of the b parameter should be based on the location of the closest free boundary to the analyzed flaw. Considering the Spray nozzle geometry, the b parameter can be quite large. The b parameter selection is further discussed in Section 4.1. Page 10 Contro U ed Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary 2.2 Fatigue Crack Growth Calculation The steps to perform fatigue crack growth calculation are presented below. Note that the analysis assumed 360° laminar flaw, which is very conservative.

Since the full circumference was assumed cracked; this section evaluated fatigue crack growth in the axial direction only. 1. For the first transient, Calculate the mode I maximum and minimum stress intensity factors (K,max and K,min) based on the maximum radial stress Ox_max and minimum radial stress Ox_min in the first transient, respectively.

Crack width (2a) and plate width (2b) are also required to calculate the SIF.

2. Calculate the stress intensity factor range due the radial stress

= K,max:...

K,min). 3. Calculate the mode II maximum and minimum stress intensity factors (K 11 max and Kumin) based on the maximum shear stress '!max and minimum shear stress '!min in the first transient, respectively.

Crack width (2a) and plate width (2b) are also required to calculate the SIF. 4. Calculate the stress intensity factor range due the shear stress

= Kumax-Kumin). 5. Combine the stress intensity factor ranges from steps 2 and 4 to calculate the effective stress intensity factor range to be used in the crack growth analysis as = + 6. To account for mean stress effect, calculate an effective R ratio (R), which is evaluated as R = 1 -I Kmax using Kmax = [(K,max)2 + (Kumax)2 f 5 and = + The R ratio is used in the crack growth equations to account for mean stress effect as described in Section 4.8. 7. Calculate crack growth increment based on R, and number of cycles per year for the specific transient.

Metal temperature is also required to determine the parameters in the crack growth rate equation.

8. Update crack length to find the crack length at the end of the transient (2af = 2ai +

where 2af is the crack length at the end of the transient, 2ai is the crack length at the beginning of the transient, and is the crack growth increment during the transient as calculated in Step 7. 9. Repeat steps 1 through 8 for transients 2 through 17 with the crack length at the end of transient 1 is used as the starting crack length for transient 2, the crack length at the end of transient 2 is used as the starting crack length for transient 3 and so on. The crack length at the end of the last transient is also the crack length at the end of one year. 10. Repeat steps 1 through 9 to find crack length at the end of subsequent years with the crack length at the end of the first year is used as the starting crack length for the second year, the crack length at the end of the second year is used as the starting crack length for the third year and so on. The process is repeated for the subsequent years for the 38 year design life. 2.3 Laminar Flaw Evaluation Disposition of all reported laminar indications per the rules of the acceptance standards in Table IWB-3514-3 of ASME B&PV Code Section XI [2] are reported in Reference

[4]. The same evaluation procedure was used in this document with the final crack length now updated with calculated crack growth for 38 years of plant operation.

For indication area the acceptance criterion is in Table IWB-3514-3

[2], which requires that A= 0.75(wxl) 7.5 in 2 Page 11 Cant oHed Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary where A is the flaw area, wand I are flaw width and length. 2.4 Minimum Required Overlay Length Calculations For overlay length evaluation, the length of the weld overlay is acceptable provided that the effective overlay length Uett) is greater than the required overlay length Ureq). The required overlay length Oreq) is the length of the weld overlay that is sufficient to transfer the load through shear back to the base metal. Conservatively a 100% through wall crack is considered in the PWSCC (primary water stress corrosion cracking) susceptible material.

The formulation in this section provides the procedure used for evaluating the minimum overlay length requirement.

The cross-sectional area (Anet) and section modulus (Znet) of the net section are calculated considering a 100% through wall crack in the PWSCC susceptible material as Jr( 2 2) Anet =4 (D+2t) -D Jr( )4 4 2 xl 2x-. (D+2t -D) z = net = ----'6"--4.:___

____ _ net (D + 2f) (D + 2t) where Dis the OD of the nozzle base metal, and tis the minimum weld overlay thickness.

The extreme fiber tensile stress is calculated based on the net section properties with faulted moment (M) and axial load (F). M F ()net = --+ --Znet Anet Conservatively consider the maximum allowable shear stress for the faulted case to be 0.6Sm (see NB-3227.2, Reference

[5]) although the faulted allowable shear stress is higher. A force balance on the FSWOL with the maximum shear stress at the interface gives Solving for the required minimum overlay length, lreq, gives / =()net Xf req 0.6Sm The effective length, lett. of the weld overlay is Page 12 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary where fwoJ is the length of the weld overlay based on the design drawings for minimum thickness conditions and lnaw is the axial dimension of the laminar flaw. Thus the length of the weld overlay is acceptable provided that lett is greater than lreq* It is noted that the initial structural overlay analysis was performed in 2007 per ASME Section Ill Subsection NB Code with 2001 and 2003 Addenda. During relief request of 2013, the shear stress

check for the laminar flaw analysis was performed per ASME Section Ill Subsection NB Code with 2004 and 2005 Addenda. Both Code years were reviewed and it was determined that the criteria for pure shear stress evaluation per NB-3227.2 are the same. Hehce, it is concluded that both Codes are applicable to the current analyses and no additional

reconciliation is required.

2.5 List of Abbreviations and Parameters This section defines the various abbreviations and parameters used throughout the document.

Abbreviations DCPP Diablo Canyon Power Plant. PZR Pressurizer DIT Design Input Transmittal PWSCC Primary Water Stress Corrosion Crack NDE Non Destructive Examination FSWOL Full Structural Weld Overlay LEFM Linear Elastic Fracture Mechanics CCP Center-Cracked Panel Model S/F Stress Intensity Factor DE Design Earthquake ODE Double Design Earthquake OBE Operation Basis Earthquake Parameters for crack growth analvsis 2a Flaw width in the axial direction used in crack growth calculations 2b Plate width parameter used in the CCP model SIF calculations K 1 Mode I stress intensity factor K 11 Mode II stress intensity factor K 1 max Maximum Mode I stress intensity factor K 1 min Minimum Mode I stress intensity factor K 11 max Maximum Mode II stress intensity factor Kumin Minimum Mode II stress intensity factor L1K 1 = K 1 max -K 1 min Mode I stress intensity factor range L1K 11 = K 11 max-Kumin Mode II stress intensity factor range L1K = {(L1K/ +(L1K 11/f" 5 Mixed mode stress intensity factor range Kmax =f(K 1 max/ +(K 11 max/f" 5 Mixed mode maximum stress intensity factor R = 1-L1K I Kmax Mixed mode R ratio Oop min Minimum operating radial stress Oop max Maximum operating radial stress rop min Minimum operating shear stress rop max Maximum operating shear stress Ox max Maximum radial stress Ox min Minimum radial stress (in) (in) (ksi"in I MPa"m) (ksi"in I MPa"m) (ksi"in I MPa"m) (ksi"in I MPa"m) (ksi"in I MPa"m) (ksi"in I MPa"m) (ksi"in I MPa"m) (ksi"in I MPa"m) (ksi"in I MPa"m) (ksi"in I MPa"m) (psi) (psi) (psi) (psi) (psi) (psi) Page 13 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Urs Residual radial stress 'Z"rs Residual shear stress ()max Maximum radial stress ()min Minimum radial stress 'Z"max Maximum shear stress 'Z"min Minimum shear stress 2ai Initial flaw width 2at Final flaw width 2L1a Flaw growth increment L1N Number of cycles per year for a given transient in one direction Parameters used in indication area evaluation A Laminar indication area evaluation w Flaw width used in the indication area evaluation I Flaw length used in the indication area evaluation Parameters for crack growth rate equations daldN Crack growth rate n Crack growth equation exponent T Temperature CA 600 ,C, Co, S, SR Coefficient in the crack growth equations R R ratio Parameters for required overlay length evaluation Anet Cross-sectional area of the weld overlay Znet Section modulus of the weld overlay 6 Tensile stress is calculated based on the net section properties net with faulted moment lreq Required overlay length to transfer the load through shear back to the base metal lett Effective length of the weld overlay !wot Length of the weld overlay based on the design drawing lnaw Axial dimension of the laminar flaw used in required overlay length assessment 00 Outer diameter 0 Diameter (same as outer diameter) t Thickness (weld overlay) F Axial load

M Bending Moment (psi) (psi) *(psi) (psi) (psi) (psi) (in) (in) (in) (cycle/year) (inz) (in) (in) (in/cycle)

CF or oc) (in 2) (in 3) (psi) (in) (in) (in) (in) (in) (in) (in) (lbf) (in-lbf) Page 14 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary 3.0 ASSUMPTIONS This section discusses the assumptions and modeling simplifications used in this document.

3.1 Unverified Assumptions There are no assumptions that must be verified before the present analysis can be used to support the disposition of the Diablo Canyon Unit 2 PZR Spray nozzle laminar indications.

3.2 Justified Assumptions

1. For the case where the R ratio < 0 (or similarly Kmin < 0), the R ratio is set equal to zero and the full range of is used in the crack growth calculations.

This is a conservative assumption since crack closure due to compressive stress field is ignored. 2. The analysis assumed 360° laminar flaw for axial fatigue crack growth calculations, which is a conservative assumption since the full circumference was assumed cracked. 3. Final circumferential flaw length was estimated by extending the flaw length in proportion to the ratio of the final flaw width to initial flaw width. This is a conservative assumption since flaw growth in the circumferential (length) direction is expected to be less than the flaw growth in the axial (width) direction.

3.3 Modeling Simplifications

1. Multiple laminar flaws in Reference

[1] are combined into larger, bounding flaws and extended to include a complete 360° arc length for crack growth calculations.

Conservatively, CCP model is used to represent the 360° laminar flaws. 2. The mode I and mode II were combined using the square root summation of squares (SRSS). This results in a more conservative crack growth estimation than the linear summation of the individual crack growth increments due mode I and mode II when the crack growth law exponent is equal to or greater than 2 (i.e. for crack growth law proportional to when n is equal to or greater than 2, combining mode I and Mode II using the SRSS method results in a conservative estimation of the crack growth increment).

3. The 2b parameter for analyzing indications 1 and 4 was defined as the distance between the point where the overlay meets the nozzle and the butter. This is a conservative value for estimating the SIF since it is much smaller than the distance between the indication and the free surfaces of the nozzle and the overlay. 4. The 2b parameter for analyzing indications 2 and 3 was defined as twice the distance between the center of the SS Weld and the point at which the design reflects the structural thickness at (0. 75[r t]112) from the toe of the weld where r is the outside radius and t is the nominal thickness.

This is a conservative value for estimating the SIF since it is much smaller than the distance between the indication and the free surfaces of the nozzle and the overlay. 5. Contripution of the external loads to the fatigue crack growth of the laminar flaws analyzed in the current document was assumed to be negligible.

This is an engineering judgment since the sustained external loads will have minimal contributions to the cyclical radial and shear stress components.

Page 15 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary 4.0 DESIGN INPUTS 4.1 Geometry Figure 4-1 shows a schematic view of the PZR Spray nozzle with FSWOL (taken from Figure 5-1 of Reference

[13]). The different parts/subcomponents of the PZR Spray nozzle are labeled in Figure 4-1. Pipe WeldOIIerlay 1 Liner/Safe End werd 1 Safe End/Pipe Weld OM Weld Safe End SJray Nozzle I Thermal Sleeve Weld I Upper Head Figure 4-1: Schematic of the Spray Nozzle with FSWOL Pertinent nozzle and overlay dimensions are estimated from references

[9 and 1 0] and are shown in Table 4-1. Table 4-1: Spray Nozzle Dimensions

[ at Indications 1 and 4(1) at Indications 2 and 3(1) Reference J (!)Indications locations are shown in Figure 4-2 and Figure 4-3. All PZR Spray nozzle indications are laminar with no planar content. The indications are located at the interface of the FSWOL and the original nozzle materials (nozzle and safe end/pipe weld). The Page 16 Contro U ed Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary indications detected in the PZR Spray nozzle are shown on Figure 4-2 and Figure 4-3, and with additional information provided in the Indication Data Sheet "WIB-345 OL Spray Nozzle" (Reference

[1]). Detailed dimensions of the Spray nozzle are in Reference

[9]. SA-508 Spray Nozz l e 2 Note: All i nd i cation l engths are u ncorrec t ed. . 1.7" 0.88" 0.5" 0.8' 1.3' 8.25" ----'.i Ind i cation #1 1" 0.75' " A" Datum -r--t---+-t-r-t-

t--t-t-----i-H-+-r+-+----t------r------f--t--+--

1 I ndication

4 0.42" Ind. 1 & 4 7 360° I nt ermittent

-.. _ _ --025'1yp typ. -\--. --. --. --. --. --**--. --. --. --. --. --./--Alloy 821182 W el d ,_-.--.--.--f.l: 312"".-:1:--.--.--.--.--. 3 1 6 SS Saf e-e nd -; . --. --. --. -----. --.--. --. + I I I I 308SSV\J\31d Alloy 52 Overlay I I 3 1 6 SS Pip i ng 0.8" Indica ti ons 2 & 3 Figure 4-2: WIB-345 Overlay Rollout Spray Nozzle (Ref. [1]) 6.125" to center of indication 5.969" to end of indicat i on SA-508 Spray Nozzle Alloy 82/182 Weld 308 SSWeld 316 SS Safe-end Alloy 52 Weld Over l ay <--Flow Figure 4-3: Spray Nozzle WIB-345 Overlay Indication Plot (Ref. [1]) Alloy 821182 Bu tte ring Page 17 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary For the conservative 20 axisymmetric analysis in this document, the circumferential content of the laminar flaws were combined and extended to include a complete 360° arc length. The longitudinal (axial) content of the laminar flaws were combined according to the proximity rules of Section XI of the ASME Code. Figure 4-4 shows idealization of the CCP Model to be used for the Spray nozzle indications.

For the four Spray nozzle indications, the flaw dimensions and the 2b dimensions required for the SIF calculations are listed in Table 4-2. Table 4-2: Dimensions for SIF Calculation Indication Flaw Width 2b Flaw Length Materials 2a (2) (in) (in) (in) 1 0.42(1) [ 1 2.0 [1] (5) Overlay I Nozzle intermittent starts 4 0.25 [ 1 and stops 360°, Overlay I Nozzle Reference

[1] <5) 2 and 3 0.312 [ 1 0.8, Reference

[12] Overlay ISS Weld Notes <1>: Actual indication 1 dimension is 0.312 in, the 0.42 in accounts for the overlap between indications 1 and 4. <2>: flaw indication lengths are obtained from Reference

[1]. <3>: Defined as the distance between the point where the overlay meets the nozzle and the butter. This value is obtained from Reference

[4], which was estimated from Detail C of Reference

[9]. This value is conservative for estimating the SIF since it is much smaller than the distance between the indication and the free surfaces of the nozzle and the overlay. <4>: Defined as twice the distance between the center of the SS Weld and the point at which the design reflects the* structural thickness at (0.75 [r t]112) from the toe of the weld where r is the outside radius and tis the nominal thickness.

This distance is given in Reference

[9] as [ . 1 The distance between the center of the SS weld to the toe of the weld was estimated from Reference

[1 0] as [ 1 in. Thus the value 2b in for this instance was estimated as [ 1 <5>: Flaws are conservatively grouped into 2 groups based on the proximity rules of Section XI of the ASME Code [2]. The first group is 0.42" wide x 16.3" long and the second group is 0.25" wide x 2.1" long. Page 18 Controlled Document A AREVA Document No. 32-9221082-003 Notes: Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis -NonProprietary For indications 1 and 4 the 2b parameter was defined as the distance between the point where the overlay meets the nozzle and the butter. This value was estimated to be [ ] . For indications 2 and 3 the 2b parameter was defined as twice the distance between the center of the SS Weld and the point at which the design reflects the structural thickness at (0. 75[r tf 12 J from the toe of the weld where r is the outside radius and t is the nominal thickness.

The 2b parameter for indications 2 and 3 was estimated to be [ ] . Figure 4-4: Idealization of the CCP Model for the Spray Nozzle Indications Page 19 ControUed Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary 4.2 Material Reference

[13] provides the material designations of various Spray nozzle components.

The materials related to the path line cases investigated in this document are listed in Table 4-3. Table 4-3: Table of Materials Location Material Spray Nozzle SA-508, Class 2 Safe End to Pipe Weld 308 SS Weld Weld Overlay Alloy 52M 4.3 External Loads Reference

[7] lists the external piping loads that were used for the PZR Spray nozzle weld overlay original crack growth analysis.

The crack growth loads applied at the safe end are presented in Table 4-4 and the crack growth loads at the nozzle are presented in Table 4-5. Note that these piping loads are not applicable to the fatigue crack growth of the laminar flaw analyzed in the current document because they have negligible contribution to the cyclical radial and shear stress components.

Reference

[11] lists the external piping loads that were used for the PZR Spray nozzle weld overlay sizing calculations.

The crack overlay sizing loads applied at the safe end are presented in Table 4-6 and overlay sizing loads at the nozzle are presented in Table 4-7. These loads were used for the minimum weld overlay length calculations performed in this document to evaluate the impact of the laminar flaws on the ability of the weld overlay to transfer the load through shear back to the base metal considering a 100% through wall crack in the PWSCC susceptible material.

Page 20 Controlled Document A AREVA Document No. 32-9221082-003

---Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table 4-4: PZR Spray Nozzle Sustained and Seismic Loading Conditions at Safe End Applicable to Crack Growth Analysis Table 4-5: PZR Spray Nozzle Sustained and Seismic Loading Conditions at Nozzle Applicable to Crack Growth Analysis Table 4-6: PZR Spray Nozzle Sustained and Seismic Loading Conditions at Safe End Applicable to Overlay Sizing Page 21 ------

Controlled Document A AREVA Document No. 32-9221082-003

-Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table 4-7: PZR Spray Nozzle Sustained and Seismic Loading Conditions at Nozzle Applicable to Overlay Sizing --4.4 Operating Transients The final flaw sizes are calculated using the same operating transients considered in the original 2007 flaw growth analysis [7]. Per Reference

[12], the number of RCS design transients is established for 60-year design life. The operating transients applicable to laminar flaw growth are listed in Table 4-8. Table 4-8: Operating Transients for PZR Spray Nozzle [7] Transient Designation Transient Name Design Number Cycles 1 HU-ES Heatup Early Spray 2 HU-LS Heatup Late Spray+ Leak Test at 2485 psig 3 CD-ES320 Cooldown Early Spray with two .LlT of -320°F spray actuations.

4 CD-LS320 Cooldown Late Spray with two .LlT of -320°F spray actuations.

250 5 CD-ES405 Cooldown Early Spray with a Ll T of -320°F and a Ll T of -405°F spray actuations.

6 CD-LS405 Cooldown Late Spray with a Ll T of -320°F and a Ll T of -405°F spray actuations.

7 PLPU Plant Loading and Plant Unloading 41,950 8 LSL Large Step Decrease in Load 250 9 SLI Step Load Increase 2,500 10 SLD Step Load Decrease 2,500 Page 22 Cant oiled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Transient Designation Transient Name Design Number Cycles 11 BCE Boron Concentration Equalization 32,000 12 LOL Loss of Load 100 13 LOP Loss of Power 50 14 LOF Loss of Flow 100 15 RT Reactor Trip 500 16 lA Inadvertent Auxiliary Spray 12 17 TRT Turbine Roll Test 10 18(1) SEISMIC(1) Seismic Loading (DE -also known as OBE) 400 Notes: (1) Seismic loading is part of the upset loading conditions.

It is not expected to contribute to the radial and shear stress components, which constitute the crack driving force for laminar flaw. Thus, Seismic loading is not considered in fatigue crack growth of laminar flaws. 4.5 Operating Stresses The cyclic operating stresses needed to calculate fatigue crack growth were obtained from a thermo elastic three-dimensional finite element analysis [13]. These fatigue stresses were developed for each of the transients at a number of time points to capture the maximum and minimum stresses due to fluctuations in pressure and temperature.

The stresses that are required for crack growth analysis for the flaws are extracted in Appendix 8 of Reference

[13]. Radial stresses contributing to Mode I crack growth are from files "SX". Shear stresses contributing to Mode II crack growth are from files "Sh". Since the SIF solutions in Section 2.1 are based on uniform stress, the stress data from Appendix 8 of Reference

[13] were sorted to obtain maximum and minimum stresses along the path. These maximum and minimum stresses are conservatively used as the stress values for SIF calculation.

In addition, the stress data were further sorted based on time points in each transient.

The maximum and minimum stresses for all time points in each transient for the each path line case are tabulated in Table 4-9 through Table 4-10. Reference

[13] provided one set of results (stresses and temperatures) for analyzing indications

1 and #4 along pathline Fline2, as shown in Figure 4-5. Similarly, Reference

[13] provided another set of results for analyzing indications

2 and #3 along path line Fline4, as shown in Figure 4-5. Since the indications in Figure 4-3 are located at the interfaces of different materials, it is not known which material the crack will grow into. Therefore, two cases were investigated for each path line based on the two materials involved.

Reference

[13] defines two pathline cases, FL2_wol and FL2_noz for Fline2; the stresses for FL2_wol were extracted by selecting FSWOL material only and the stresses for FL2_noz were extracted by selecting nozzle material only. Similarly, for pathline Fline4 cases FL4_wol and FL4_wld were defined by selecting FSWOL material and weld material, respectively.

This document calculates fatigue crack growths on these four cases. Page 23 Contro l led Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Safe End/Pipe Weld Safe End DM Weld and Butter Y (Axial) Lx(Radial)

Nozzle Fline4 (incl. FL4_wol and FL4_wld) SWOL Fline2 (incl. FL2_wol and FL2_noz)

Only laminar indications are found along path lines FLine2 (indications 1 and 4} and Fline 4 (indications 2 and 3}.

FLine2 is path line used to sample results for evaluating laminar indications 1 and 4

FL2_wol used SWOL materia/for extracting stresses

FL2_noz used nozzle material for extrqcting stresses

FLine4 is path line used to sample results for evaluating laminar indications 2 and 3 I .

FL4_ wol used SWOL material for extracting stresses

FL4_ wid used weld material for extracting stresses . Figure 4-5: PZR Spray Nozzle with Path Lines Superposed Page 24 Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table 4-9: Maximum and Minimum Stresses for Indications 1 and 4 (Pathline Fline2) Path Case FL2_wol Path Case FL2_noz Minimum Maximum Minimum Maximum Minimum Maximum Minimum Maximum Transient Radial Stress Radial Stress Shear Stress Shear Stress Radial Stress Radial Stress Shear Stress Shear Stress (Omin) (Omax) ("tmin) ("tmax} (amin) (Omax) ("tmin} ("tmax) (ksi) (ksi) (ksi) (ksi) (ksi) (ksi) (ksi) (ksi) Page 25 ControUed Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table 4-10: Maximum and Minimum Stresses for Indications 2 and 3 (Path line Fline4) Path Case FL4_wol Path Case FL4_wld Minimum Maximum Minimum Maximum Minimum Maximum Minimum Maximum Transient Radial Stress Radial Stress Shear Stress Shear Stress Radial Stress Radial Stress Shear Stress Shear Stress (amin) (Omax) {tmin) (tmax) (amin) (Omax) (tmin) {tmax) (ksi) (ksi) (ksi) (ksi) (ksi) (ksi) (ksi) (ksi) Page 26 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary 4.6 Operating Temperatures Metal temperature is required for crack growth calculations.

Metal temperatures along path lines were extracted in Appendix B of Reference

[13] with file names "TH". The maximum temperatures along each pathline for all time points within each transient were determined to be used for crack growth calculation.

Using the maximum temperature for fatigue crack growth calculation is conservative because higher temperatures result in higher crack growth rates based on the formulation given in Section 4.8. The maximum temperatures at all path cases during transients are tabulated in Table 4-11. Table 4-11: Maximum Temperatures for Path Line Cases (Units: °F) Indications 1 and 4 Indications 2 and 3 Transient (Pathline Fline2) (Pathline Fline4) 4.7 Residual Stresses Residual stresses due to Alloy 52M WOL are analyzed in Reference

[14]. The residual stresses at the flaws investigated are extracted in Appendix C of Reference

[14]. The minimum and maximum values from the bounding cases of radial and shear stresses are tabulated in Table 4-12. Residual stresses will be combined with operating stresses (Table 4-9 and Table 4-1 0) for SIF calculations.

Page 27 Controlled Document A AREVA Document No. 32:.9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table 4-12: Bounding Radial and Shear Weld Residual Stresses for Laminar Flaws Location Radial Stress Shear Stress (ksi) (ksi) 4.8 Fatigue Crack Growth Laws Fatigue crack growth models for materials in Table 4-3 are described in the subsections below. Since the flaws in Figure 4-2 and Figure 4-3 do not come in contact with the reactor coolant, crack growth formulae that are applicable in the presence of air environment are used. 4.8.1 Alloy 52 and 52M (FSWOL) The fatigue crack growth model for Alloy 52 and 52M is obtained from Reference

[15], which uses a multiplier of 2 upon those of Alloy 600. The crack growth rate (CGR) equation for Alloy 600 is given in NUREG/CR-6721

[16]. The CGR equation for Alloy 52 and 52M is expressed as, dN A52/52M dN A600 Substituting the Alloy 600 crack growth equation, = 2. CA600SR(MY dN A52!52M Where IlK is the stress intensity factor range in terms of MPavm and da/dN is the crack growth rate in the units of meter/cycle.

The other parameters are defined as, CA 6 oo = 4.835x10-14 + 1.622x10-16 T -1.490x10-18 T 2 + 4.355x10-21 T 3 = Kmax -Kmin. R=Kmin Kmax SR = (1-0.82Rt 2" 2 n =4.1 T = metal temperature in oc For the combined mode loading due to the opening mode (mode I) and sliding mode (mode II) the parameter was estimated as Page 28 ControUed Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary with L1K1 and L1K 1 1 defined as. L1K1 = Klmax -Klmin L1K11 = K11max -Kllmin Where K1max and Klmin are the maximum and minimum mode I stress intensity factors, and K 11 max and K11min are the maximum and minimum mode II stress intensity factors. a conservative estimation of the R ratio is given by R = 1 -L1K /Kmax where Kmax is estimated as For the case where the R ratio < 0 (or similarly Kmin < 0), the R ratio is set equal to zero and the full range of L1K is used in the crack growth calculations.

This is a conservative assumption since crack closure due to compressive stress field is ignored. 4.8.2 Stainless Steel (308 55 Weld) The fatigue crack growth model for stainless steel is obtained from Reference

[2] Article C-841 0. The CGR equation for stainless steel is expressed as, = Co(L1K)n dN SS-air Where ilK is the stress intensity factor range in terms of ksi.Vin and da/dN is the crack growth rate in the units of in/cycle.

The other parameters are defined as, = Kmax -Kmin R=Kmin Kmax n=3.3 C 0 = CxS C = 10(-w.oo9

+8.12 x io -4 T-1.13 x io -6 y 2 +l.02 x 10 -9 y 3) !1.0 when R:::; 0 S = 1.0 + 1.8R when 0 < R :::; 0. 79 -43.35 + 57.97R when 0.79 < R < 1.0 Page 29 Contro l led Document.

A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary T = metal temperature in oF For the combined mode loading due to the opening mode (mode I) and sliding mode (mode II) the parameter was estimated as with and defined as = Klmax -Klmin

= Knmax-Knmin Where K1max and K1min are the maximum and minimum mode I stress intensity factors, and K11max and K11min are the maximum and minimum mode II stress intensity factors. a conservative estimation of the R ratio is given by R = 1 -/Kmax where Kmax is estimated as 4.8.3 Low-Alloy Steel (SA-508) The fatigue crack growth model for low-alloy steel is obtained from Reference

[2] Article A-4300. The CGR equation for low-alloy steel is expressed as, =

dN LAS Where .ilK is the stress intensity factor range in terms of ksi.Vin and da/dN is the crack growth rate in the units of in/cycle.

The other parameters are defined as, R=Kmin Kmax { 5.0 for R < 0 -th -5.0(1-0.8R) for 0 :s; R < 1.0 For 0 :s; R::; 1 , {S =

Rt -Kmax -Kmin { s =1 ForR< 0, _ _ -Kmax Kmin Page 30 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary

{0 for <

Co= 1.99x10-10 S for n = 3.07 *Note that for the case where the R ratio < 0 (or similarly Kmin < 0), it is assumed that S = 1 and L1K = Kmax -Kmin* This is a conservative assumption since crack closure due to compressive stress field is ignored. For the combined mode loading due to the opening mode (mode I) and sliding mode (mode II) the parameter L1K was estimated as with L1K 1 and L1K 11 defined as. L1K, = Klmax -Klmin L1K11 = Kllmax -Kllmin Where K1max and K,min are the maximum and minimum mode I stress intensity factors, and K 11 max and Kllmin are the maximum and minimum mode II stress intensity factors. a conservative estimation of the R ratio is given by R = 1 -L1K /Kmax where Kmax is estimated as Page 31 Contro ii ed Document A. AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary 5.0 COMPUTER USAGE 5.1 Software and Hardware Mathcad [17] is used in this calculation.

The hardware platform (Service Tag# 5VJV5S1) is Intel CoreŽ i7-2640M CPU 2.80 GHz, 8.00 GB RAM. The operating system is Microsoft Windows 7 Enterprise, Copyright© 2009, Service Pack 1. 5.2 Computer Files Table 5-1 lists the computes files used in this document.

Files "Spray.xlsm" and "spray.xmcd" are from the previous revision of the document and were used to perform the calculations contained in the main body of the document.

Only file "spray_Uncertainty.xmcd" was used in this revision, which contains the calculations performed in Appendix A. The computer files used in this document are available in AREVA ColdStor storage as indicated in Table 5-1. Table 5-1: Computer Files File Name Date &Time Checksum File Description ColdStor location:

\\cold\General-Access\32\32-9000000\32-9213780-002\official (revision 002 files) spray_ Uncertainty .xmcd Apr 29 2014 13:23:36 64547 Mathcad file to calculate fatigue crack growth for all path lines for measurement uncertainty case. ColdStor location:

\\cold\General-Access\32\32-9000000\32-9213780-001\official (revision 001 files) Spray.xlsm Mar 05 2014 15:42:31 02092 Excel spreadsheets to verify crack growth calculation and perform laminar flaw qualification I calculations spray.xmcd Mar 05 2014 15:42:11 50252 Mathcad file to calculate fatigue crack growth for all path lines Page 32 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary 6.0 CALCULATIONS The fatigue crack growth analysis methods outlined in Section 2.2 were used to calculate the final crack sizes for all cracks at the end of 38 years. A total of four cases (along two path lines) were analyzed in this document.

All calculations were performed using Mathcad and Excel spreadsheet, as listed in Table 5-1. The remainder of this section contains sample calculations illustrating the fatigue crack growth analysis for each of the three materials considered in the current document (Alloy 52M, Stainless Steel , and Low Alloy Steel). In each sample calculation, detailed calculations are shown to illustrate fatigue crack growth increment for one transient.

The manual calculations were repeated for all transients (not shown in the document) to assure that the manual calculations confirms the results for the first year as reported in Section 7.0. 6.1 Alloy 52M (Weld Overlay) Path line cases FL2_wol and FL4_wol are located at Alloy 52M material.

Using FL4_wol as an example, for transient

1 at the beginning of the first year, Given: Oop min = [ ] ksi (Table 4-10) Oop max = [ ] ksi (Table 4-1 0) 1'op_min t = [ ] ksi (Table 4-1 0) 1'op_max t = [ ] ksi Table 4-1 0) Ors = [ ] ksi (Table 4-12) 1'rs = [ ] ksi (Table 4-12) Note* t: conservatively using the largest magnitude of shear stress since the sign in shear only represents the direction of the stress. 2a = 0.312 in (Table 4-2) 2b = [ ] in (Table 4-2) T = [ ] OF (Table 4-11) = [ ] oc Number of Cycles 60 years = [ ] cycles (Table 4-8) = [ ] cycles/year Omin = Oop_min + Ors = [ ] ksi [ ] MPa Omax = Oop_max + Ors = [ ] ksi [ ] MPa "Cmin = "Cop_min + "Crs = [ ] ksi [ ] MPa "Cmax = "Cop_max + "Crs = [ ] ksi [ ] MPa alb = [ ] f(a/b) = (1-0.025(a/b) 2+0.06*(a/b)

4) [sec(na/2b)]

0*5 = [ ] Klmin = O'maxv(na) f(a/b) = [ ] ksi"in Klmax = O'minv(na) f(a/b) = [ ] ksi"in Page 33 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Knmin = 'tmax"V(na) f(a/b) = [ ] ksi"in Knmax = 'tminv(na) f(a/b) = [ ] ksi"in = Klmax -Klmin = [ ] ksi"in

= Knmax -Kllmin = [ ] ksi"in = (

+ = [ ] ksi"in [ ] MPavm Kmax = (Kima/ + Kllma/)0" 5 = [ ] ksi"in R = 1 -I Kmax = [ ] sR = (1 -o.82 Rr 2*2 = [ ] CA600 = 4.835 X 10-14 + 1.622 X 10 -16 X T = [ ] -1.490 X 10 -18 X T 2 + 4.355 X 10 -21 X T 3 !J.a = .!J.N(2 CA6oo SR = [ ] m = [ ] in 2a = 2a + 2 !J.a = 0.312039 in The calculated 2a = 0.312039" is the initial 2a for the next transient crack growth calculation.

After going through all 17 transients in the first year, the crack grows from 0.312" to 0.312358", which confirms the results reported in Table 7-3 for the first year. Then, this 0.312358" is used as the initial crack length for the second year calculation and so on. Thus by repeating the process the final flaw size at the end of 38 years is obtained.

6.2 Stainless Steel (Pipe to Safe End Weld) Path line case FL4_wld is located at stainless steel material.

For transient

1 at the beginning of the first year, Given: Oop min = Oop_max = Top_min t = Top_max t = Ors = Trs = [ ] [ ] [ ] [ ] [ ] [ ] ksi ksi ksi ksi ksi ksi (Table 4-1 0) (Table 4-1 0) (Table 4-10) (Table 4-1 0) (Table 4-12) (Table 4-12) Note t: switching the signs of maximum negative and positive shear stresses since the sign in shear only represents the direction of the stress. Page 34 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary 2a = 0.312 in (Table 4-2) 2b = [ 1 in (Table 4-2) T = [ 1 OF (Table 4-11) Number of Cycles 60 years = [ 1 (Table 4-8) llN = [ 1 cycles/year Omin = Oop_min + Ors = [ 1 ksi Omax = Oop_max + Ors = [ 1 ksi "tmin = "top_min + "trs = [ 1 ksi "tmax = "top_max + "trs = [ 1 ksi alb = [ 1 f(a/b) = (1-0.025(a/b) 2+0.06*(a/b)

4) [sec(na/2b)]

0*5 = [ 1 Klmin = <Jmaxv(na) f(a/b) = [ 1 ksi.Yin K1max = <Jminv(na) f(a/b) = [ 1 ksi.Yin Kumin = "tmaxv(na) f(a/b) = [ 1 ksi.Yin K11max = "tminv(na) f(a/b) = [ 1 ksi.Yin L1K1 = Klmax -Klmin = [ 1 ksi.Yin L1Ku = Kumax-Kumin = [ 1 ksi.Yin L1K = ( L1K1 2 + L1K 11 2 f 5 = [ 1 ksi.Yin Kmax= (Kima/ + Kllma/)0" 5 = [ 1 ksi.Yin R = 1 -L1K I Kmax = [ 1 S (Section 4.8.2) = [ 1 C = 1 Q (-10.009 + 8.12 xlO -4 T -1.13 xlO -6 T 2 +1.02 x 10 -9 T 3) = [ 1 Co= CS = [ 1 lla = llN(ca L1K 3*3) = [ 1 in 2a = 2a + 2lla = 0.312006 in The calculated 2a = 0.312006" is the initial 2a for the next transient crack growth calculation.

After going through all 17 transients in the first year, the crack grows from 0.312" to 0.312166", which confirms the results reported in Table 7-4 for the first year. Then, this 0.312166" is used as the initial crack length for the second year calculation and so on. Thus by repeating the process the final flaw size at the end of 38 years is obtained.

Page 35 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary 6.3 Low-Alloy Steel (SA 508 Nozzle Material)

Path line case FL2_noz is located at low-alloy steel material.

For transient

1 at the beginning of the first year, Given: Oop min = [ ] ksi (Table 4-9) Oop max = [ ] ksi (Table 4-9) Lop_min t = [ ] ksi (Table 4-9) Top_max t = [ ] ksi (Table 4-9) Ors = [ ] ksi (Table 4-12) Trs = [ ] ksi (Table 4-12) Note t: conservatively using the largest magnitude of shear stress, which is from the maximum negative stress. 2a = 0.4200 in (Table 4-2) 2b = [ ] in (Table 4-2) T = [ ] OF (Table 4-11) Number of Cycles 60 years = [ ] (Table 4-8) LlN = [ ] cycles/year Omin = Oop_min + Ors = [ ] ksi Omax = Oop_max + Ors = [ ] ksi 'tmin = 'top_min + 'trs = [ ] ksi 'tmax = 'top_max + 'trs = [ ] ksi alb = [ ] f(a/b) = (1-0.025(a/b

)2+0. 06*(a/b )4) [sec(rca/2b )f*5 = [ ] Klmin = <Jmaxv'(rca) f(a/b) = [ ]

Klmax = <Jminv'(rca) f(a/b) = [ ]

Kumin = 'tmaxv'(rca) f(a/b) = [ ]

Kumax = 'tminv'(rca) f(a/b) = [ ]

ilK, = Klmax -Klmin = [ ]

ilKu = Kumax-Kumin = [ ]

ilK = ( ilK,z + ilKuz)o.s = [ ]

Kmax = (Kima/ + Kuma/)0" 5 = [ ]

R = 1 -ilK I Kmax = [ ] ilKth = = [ ]

S (Section 4.8.3) = [ ] Co (Section 4.8.3) = [ ] Lla = LlN(C 0 ilK 3.07) = [ ] in 2a = 2a + 2 Lla = 0.420004 in Page 36 Contro U ed Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary The calculated 2a = 0.420004" is the initial 2a for the next transient crack growth calculation.

After going through all 17 transients in the first year, the crack grows from 0.42" to 0.420058", which confirms the results reported in Table 7-2 for the first year. Then, this to 0.420058" is used as the initial crack length for the second year calculation and so on. Thus by repeating the process the final flaw size at the end of 38 years is obtained.

7.0 RESULTS 7.1 Fatigue Crack Growth The crack sizes during 38 years of plant operations due to fatigue crack growth are presented in Table 7-1 through Table 7-4. The final crack sizes for all cases are summarized in Table 7-5. For indications 1 and 4 (considering cases FL2_noz and FL2_wol), the larger crack growth was observed for case FL2_noz. The final flaw size for indications 1 and 4 was estimated to be 0.422204 in. For indications 2 and 3 (considering cases FL4_wld and FL4_wol), the larger crack growth was observed for case FL4_wol. The final flaw size for indications 2 and 3 was estimated to be 0.326246 in. These two bounding crack sizes are used for laminar flaw evaluations in Section 7.2. Table 7-1: Fatigue Crack Growth for Indications 1 and 4 (Case FL2_wol) Year Year Start Crack Size Crack Growth Year End Crack Size (in.) (in.) (in.) 1 0.420000 0.000046 0.420046 -3 5 7 -8 9 10 11 12 13 14 I I -Page 37

Document A AREVA Document No. 32-9221 082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Year Year Start Crack Size Crack Growth Year End Crack Size (in.) (in.) (in.) 15 17 19 21 23 25 27 29 31 33 35 37 0.421726 0.000047 0.421773 Page 38

Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table 7-2: Fatigue Crack Growth for Indications 1 and 4 (Case FL2_noz) Year Year Start Crack Size Crack Growth Year End Crack Size (in.) (in.) (in.) 1 0.420000 0.000058 0.420058 --2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 I I -Page 39 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Year Year Start Crack Size Crack Growth Year End Crack Size (in.) (in.) (in.) 27 29 31 33 35 37 I I -38 0.422145 0.000058 0.422204 Page 40 Controlled Document A .AREV.A* Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table 7-3: Fatigue Crack Growth for Indications 2 and 3 (Case FL4_wol) Year Year Start Crack Size Crack Growth Year End Crack Size (in.) (in.) (in.) 1 0.312000 0.000358 0.312358 --2 4 6 8 10 12 14 16 18 20 22 24 26 -Page 41 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Year Year Start Crack Size Crack Growth Year End Crack Size (in.) (in.) (in.) !""""-'" .-27 28 29 30 31 32 33 34 35 36 37 ...... I I -38 0.325854 0.000393 0.326246 Page 42 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table 7-4: Fatigue Crack Growth for Indications 2 and 3 (FL4_wld)

Year Year Start Crack Size Crack Growth Year End Crack Size (in.) (in.) (in.) 1 0.312000 0.000166 0.312166 -r-oo-2 4 6 8 10 12 14 16 18 20 22 24 26 I I -Page 43 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Year Year Start Crack Size Crack Growth Year End Crack Size (in.) (in.) (in.) 27 29 31 33 35 37 -38 0.318235 0.000172 0.318406 Page 44 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table 7-5: Summary of Fatigue Crack Growth Indication Case Initial Crack Size Final Crack Size Growth (in.) Crack (in.)

Increase (%) FL2_wol 0.420000 0.421773 0.001773 0.42% 1 and 4 FL2_noz 0.420000 0.422204 0.002204 0.52% FL4_wol 0.312000 0.326246 0.014246 4.6% 2 and 3 FL4_wld 0.312000 0.318406 0.006406 2.1% 7.2 Laminar Flaw Evaluation The flaw area calculations are presented in Table T-6. Based on the areas calculated in Table 7-6, it is concluded that the laminar flaws meet the laminar flaw acceptance criterion in article IWB-3514-3 of Section XI of the ASME Code [2] after 38 years of plant operation.

The minimum required overlay length evaluation is performed in Table 7-7. It is seen from Table 7-7 that the effective overlay length (left), evaluated as the actual overlay length Uwot) minus the flaw length (/flaw), is greater than the minimum required overlay length Ureq), which is estimated based on Section II I of the ASME Code [3]. Thus, it is concluded that the laminar flaws will not impact the overlay integrity after 38 years of plant operation.

Page 45 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table 7-6: Flaw Area Evaluation Indications 1 Indications 1 Indications Reference/Comments and 4 and 4 2 and 3 (1st Group) (2nd Group) Initial flaw width Winitial (in.) 0.42 0.42 (2) 0.312 Table 4-2 Final flaw width Wfinal (in.) 0.422204 0.422204 0.326246 Table 7-5 Initial flaw length !initial (in.) 16.3 2.1 0.8 Table 4-2 Final flaw /ength(1 J /final= (Wfinal 16.38554 2.11102 0.815615 I Winitial ) !initial (in.) Acal = 0. 75{Wfinal X ffinaJ (in 2) 5.19 0.67 0.20 Section 2.3 Alimit (in 2) 7.5 7.5 7.5 Table IWB-3514-3 of [2] Check Acal S Alimit OK OK OK Notes (1): Geometric similar flaw growth is assumed in the growth analysis.

This assumption maintains a constant aspect ratio as defined by the initial flaw, winitial//initial*

The final flaw length, ltinal was computed based on wfinal determined in the growth analysis.

The assumption of geometric flaw shape in the growth analysis is conservative since the cyclic stresses acting at the flaw plane are taken as uniform stress over the flaw area. Under uniform stress conditions, the flaw aspect ratio will decrease during growth making the /final smaller than that computed by the constant aspect ratio assumption.

(2): Actual flaw width for second group of indications 1 and 4 was listed in Table 4-2 to be 0.25". 0.42" was conservatively used in the area evaluation.

Page 46 Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table 7-7: Overlay Length Evaluation Parameter Indications Indications Reference/Comments

_1 and 4 2 and 3 -t (in) D (in) Znet = 21(0+2t) (n/64) [(D+2t)4-D 4] (in 3) Anet = (n/4) [(D+2t)2-D 2] (in 2) M (in-lbf) MIZnet (psi) F (lbf) F I A net (psi) O"net = MIZnet + FIAnet (ksi) Sm (ksi) -lreq = O"net t I 0.6Sm (in) lwol (in) --lflaw (in) 0.4222 0.3262 Table 7-5 leff = lwol -lflaw (in) [ ] [ ] Check leff > lreq OK OK [ ] Page 47 C ontro l led Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary

8.0 REFERENCES

1. AREVA Document 38-9200149-001, "DCPP Unit 2 Pressurizer Nozzle NDE Data" 2. ASME Boiler and Pressure Vessel Code,Section XI, 2004 Edition with Addenda through 2005 3. ASME Boiler and Pressure Vessel Code, Section Ill, 2004 Edition with Addenda through 2005 4. AREVA Document 32-9199937-001, "DCPP Unit 2-Evaluation of Laminar Indications on Pressurizer Nozzles" 5. "Safety Evaluation by the Office of Nuclear Reactor Regulation

-Request for Relief from the American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, lnservice Inspection Program, Pacific Gas and Electric Company, Diablo Canyon Power Plant, Unit 2 Docket No. 50-323" Dated February 6, 2008 (ADAMS No. ML080110001)

6. AREVA Document 32-9199805-001, "Diablo Canyon Power Plant Unit 2 PZR Safety and Spray Nozzles Planar Flaw Analysis" 7. AREVA Document 32-9049064-001, "Diablo Canyon Unit 2 PZR Spray Nozzle Weld Overlay Crack Growth Evaluation" 8. Hiroshi Tada, Paul C. Paris, George R. Irwin, "The stress analysis of cracks handbook", 3rd edition, ASME, 2000 9. AREVA Drawing 02-8019233D-001, "Diablo Canyon Pressurizer Spray Nozzle Weld Overlay Design Input" 10. AREVA Drawing 02-8018400C-002, "Diablo Canyon Unit 2 Pressurizer Spray Nozzle Existing Configuration." 11. AREVA Document 32-9043546-001, "Diablo Canyon Unit 2, Pressurizer Spray Nozzle Weld Overlay Sizing Calculation" 12. AREVA Document 38-9046469-002, "DCPP 2 Pressurizer Nozzle Weld Overlay Design Non-proprietary" 13. AREVA Document 32-9049112-005, "Diablo Canyon Unit 2-Pressurizer Spray Nozzle Weld Overlay Structural Analysis" 14. AREVA Document 32-9049061-007, "Diablo Canyon Unit 2 Pressurizer Spray Nozzle Weld Overlay Residual Stress Analysis" Page 48 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary

15. AREVA Document 32-9055891-006, "Fatigue and PWSCC Crack Growth Evaluation Tool AREVACGC" 16. NUREG/CR-6721, "Effects of Alloy Chemistry, Cold Work, and Water Chemistry on Corrosion . Fatigue and Stress Corrosion Cracking of Nickel Alloys and Welds," U.S. Nuclear Regulatory Commission (Argonne National Laboratory), April 2001 17. Mathcad 15.0 Software, Parametric Technology Corporation, 140 Kendrick Street, Needham, MA 02494 USA Page 49

Controlled Document *A. AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary APPENDIX A: FLAW SIZE UNCERTAINTY CONSIDERATION This appendix contains a sensitivity analysis to account for NDE uncertainty in flaw size measurement.

The NDE uncertainty was estimated in Reference

[A.1] to be +/-0.125 inch on either side of the flaw or 0.25 inch total for the axial dimension of the laminar flaws. Incrementing the detected flaw sizes by 0.25 inch, the flaw size to be used for flaw evaluation becomes 0.67 inch for indications 1 and 4 and 0.562 inch for indications 2 and 3. Using the updated flaw sizes, the crack growth analysis was performed following the procedure outlined in the main body of the document.

The operating and residual stresses used for the crack growth analysis in this appendix are the same as the operating and residual stresses used in the main body of the document.

The operating stresses used for the crack growth analysis are tabulated in Table 4-9 and Table 4-10 and the weld residual stresses are tabulated in Table 4-12. The path lines considered in the main body of the document are of sufficient lengths that they cover the +/-0.125 inch uncertainty on either side of the laminar indications.

The flaw growth evaluations were performed considering the design transients for the 38-year design life of the weld overlays.

The results of the flaw growth analysis are tabulated in Table A-1. Table A-1: Results of Flaw Growth Analysis with 0.25 in NDE Uncertainty Indication Case Initial Crack Final Crack Size Growth (in.) Crack Increase Size (in.) (in.) (%) FL2_wol 0.67 1 and 4 0.676068 0.006068 0.9% FL2_noz 0.67 0.6,75527 0.005527 0.8% FL4_wol 0.562 0.619845 0.057845 10.3% 2 and 3 FL4_wld 0.562 0.580967 0.018967 3.4% The flaw area calculations are presented in Table A-2 and are based on increasing the width of the indications by 0.25 inch to account for NDE sizing uncertainty.

Based on these area calculations, it is concluded that the laminar indications in the second grouping for Indications 1 and 4, and Indications 2 and 3, meet the laminar flaw acceptance standards in Article IWB-3514.6 of Section XI of the ASME Code after 38 years of plant operation.

Indications 1 and 4 evaluated as Group 1 exceeds the allowable area limit of 7.5 in 2 (8.33 in 2 > 7.5 in 2) for this assessment.

The Group 1 evaluation conservatively assumes the length of the indication to be continuous over 16.4 inches (using a smaller measurement uncertainty that is approximately 75% of the assumed 0.25 inch increase in overall indication width will satisfy the acceptance standards of IWB-3514.6 (Table IWB-3514-3)).

Page 50 Controlled Document A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table A-2: Laminar Area Evaluation with 0.25 in NDE Uncertainty Indications 1 Indications 1 Indications Reference/Comments and 4 and 4 2 and 3 (1st Group) (2nd Group) Initial flaw width Winitial (in.) 0.67 0.67(2) 0.562 Table A-1 Final flaw width Wfinal (in.) 0.676068 0.676068 0.619845 Table A-1 Initial flaw length !initial (in.) 16.3 2.1 0.8 Table 4-2 Final flaw length(1 J !final= (wfinal 16.44762 2.11902 0.88234 I Winitial ) !initial (in.) Acal = 0. 75{Wfinal X /final) (in 2) 8.33978(3) 1.07445 0.41019 Section 2.3 Alimit (in 2) 7.5 7.5 7.5 Table IWB-3514-3 of [2] Check Acal :s; Alimit NO YES YES Notes <1): Geometric similar flaw growth is assumed in the growth analysis.

This assumption maintains a constant aspect ratio as defined by the initial flaw, Winitial//initial*

The final flaw length, !final was computed based on wfinal determined in the growth analysis. The assumption of geometric flaw . shape in the growth analysis is conservative since the cyclic stresses acting at the flaw plane are taken as uniform stress over the flaw area .. Under uniform stress conditions, the flaw aspect ratio will decrease during growth making the !final smaller than that computed by the constant aspect ratio assumption.

<2): Actual flaw width for second group of indications 1 and 4 was listed in Table 4-2 to be 0.25". 0.67" (Including uncertainty) was conservatively used in the area evaluation.

<3>: Note that this value is more than the area limit (7.5 in 2 ). However, on further analytical evaluation as permitted by IWB-3132.3, it is found to be acceptable as shown below. To assess the significance of not meeting the NDE acceptance standards of IWB-3514.6 (Table IWB-3514-3), flaw acceptance was evaluated by analysis.

Flaw acceptance by analytical evaluation is permitted by IWB-3132.3 when acceptance standards are exceeded.

In this application, the analytical evaluation is based on Section Ill design rules to establish the allowable overlay weld length. The minimum required overlay length evaluation is summarized in Table A-3 where the effective overlay length Uett) is evaluated as the actual overlay length Uwol) minus the flaw length Unaw). As seen in Table A-3, the overlay minimum length requirement is still satisfied for all flaws. For indications 1 and 4, the overlay minimum required length Ureq) is [ ] in, which is less than the effective overlay length Uett) of [ ] . For indications 2 and 3, the overlay minimum required length Ureq) is [ ] which is less than the effective overlay length Uett) of [ ]. Thus, it is concluded that the laminar indications, including Indications 1 and 4 (Group 1) will not impact the integrity of the overlay for 38 years of plant operation.

Page 51 Controlled ocument *A AREVA Document No. 32-9221082-003 Diablo Canyon Unit 2 Pressurizer Spray Nozzle Laminar Flaw Analysis-NonProprietary Table A-3: Overlay Length Evaluation with 0.25 in NDE Uncertainty Parameter Indications 1 Indications 2 Reference/Comments and 4 and 3 lreq = <Jnet t I 0.6Sm (in) [ ] [ ] Table 7-7 lwol (in) [ ] [ ] Table 7-7 ltlaw (in) 0.676068 0.619845 Table A-1 leff = lwol -ltlaw (in) [ ] [ ] Check leff > lreq YES YES Conclusion The analysis presented above confirms that the SWOL with postulated flaws accounting for an NDE measurement uncertainty of +/-0.125 inch on either side of the flaw or 0.25 inch total for the axial dimension of the laminar flaws still meets the overlay length requirement per NB-3227.2[3]

in Spray Nozzle. Thus, it is concluded that the laminar indications, including Indications 1 and 4 (Group 1) will not impact the integrity of the SWOL for 38 years of plant operation.

References A.1. AREVA Document 38-9223975-000 "DCPP2-NDE Measurement Uncertainty Information." Page 52

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SUMMARY

SUMMARY

1.0 INTRODUCTION

8.0 REFERENCES

1.0 INTRODUCTION

8.0 REFERENCES

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