ML20329A345

Relief Request Associated with N-16A Reactor Pressure Vessel Instrument Nozzle Repairs - Submittal of Analyses

ML20329A345
Person / Time
Site:	Peach Bottom
Issue date:	11/24/2020
From:	David Helker, Opsal P Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML20329A344	List: ML20329A345
References
Download: ML20329A345 (103)

Text

200 Exelon Way Kennett Square, PA 19348 www.exeloncorp.com PROPRIETARY INFORMATION - WITHHOLD UNDER 10 CFR 2.390 10 CFR 50.55a November 24, 2020 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Peach Bottom Atomic Power Station, Unit 2 Renewed Facility Operating License No. DPR-44 NRC Docket No. 50-277

Subject:

Relief Request Associated with N-16A Reactor Pressure Vessel Instrument Nozzle Repairs - Submittal of Analyses

References:

1. Letter from D. P. Helker (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "Proposed Relief Request Associated with N-16A Reactor Pressure Vessel Instrument Nozzle Repairs," dated November 4, 2020 (ML20309B020)

2. Email from J. Tobin (U.S. Nuclear Regulatory Commission) to D. Helker (Exelon Generation Company, LLC), "Peach Bottom Verbal Relief for Penetration Nozzle (EPID: L-2020-LLR-0144)," dated November 6, 2020 (ML20314A028)

In Reference 1, in accordance with 10 CFR 50.55a, Exelon Generation Company, LLC (EGC) requested approval of a relief request associated with the repair of a 2-inch instrument line nozzle at penetration N-16A on the Reactor Pressure Vessel (RPV). Reference 2 provided the U.S. Nuclear Regulatory Commission (NRC) verbal authorization of the repair.

As discussed in Reference 1, EGC committed to supplying the final one-cycle flaw analytical evaluation, evaluation of repair, and the corrosion evaluation. Attached are these analyses.

Attachments 1 (Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification, Document Number 32-9321034-002), 2 (Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification, Document Number 32-9321033-003), and 3 (Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification, Document Number 51-9320932-001) contain information proprietary to Framatome Inc. (Framatome). Framatome requests that these documents be withheld from public disclosure in accordance with 10 CFR 2.390(a)(4). An affidavit supporting this request is contained in Attachment 4. Attachments 5, 6, and 7 contain non-proprietary versions of the Framatome documents.

Attachments 1, 2 and 3 contain proprietary information - the balance of this letter is considered non-proprietary when Attachments 1, 2 and 3 are removed.

Peach Bottom Atomic Power Station, Unit 2 Relief Request Associated with N-16A Reactor Pressure Vessel Instrument Nozzle Repairs - Submittal of Analyses November 24, 2020 Page 2 If you have any questions or require additional information, please contact Tom Loomis at 610-765-5510.

Sincerely, David P. Helker Sr. Manager - Licensing Exelon Generation Company, LLC Attachments: 1) Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification," Document Number 32-9321034-002 (Proprietary Version)

2) Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification," Document Number 32-9321033-003 (Proprietary Version)

3) Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification," Document Number 51-9320932-001 (Proprietary Version)

4) Affidavit

5) Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary, Document Number 32-9321037-001 (Non-Proprietary Version)

6) Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary, Document Number 32- 9321035-001 (Non-Proprietary Version)

7) Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification, Document Number 51-9321006-001 (Non-Proprietary Version) cc: USNRC Region I, Regional Administrator USNRC Senior Resident Inspector, PBAPS USNRC Project Manager, PBAPS W. DeHass, Pennsylvania Bureau of Radiation Protection Affidavit

AFFIDAVIT

1. My name is Philip A. Opsal. I am Manager, Product Licensing for Framatome Inc. (formally known as AREVA Inc.), and as such I am authorized to execute this Affidavit.

2. I am familiar with the criteria applied by Framatome to determine whether certain Framatome information is proprietary. I am familiar with the policies established by Framatome to ensure the proper application of these criteria.

3. I am familiar with the Framatome information contained in the following Reports referred to herein as Documents.:

Framatome Engineering Information Record 51-9320932-001, Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification, November 2020 Framatome Calculation Summary Sheet (CSS) 32-9321033-003, Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification, November 2020 Framatome Calculation Summary Sheet (CSS) 32-9321034-002, Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification, November 2020 Information contained in these Documents has been classified by Framatome as proprietary in accordance with the policies established by Framatome for the control and protection of proprietary and confidential information.

4. These Documents contain information of a proprietary and confidential nature and is of the type customarily held in confidence by Framatome and not made available to the

public. Based on my experience, I am aware that other companies regard information of the kind contained in these Documents as proprietary and confidential.

5. These Documents have been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in these Documents be withheld from public disclosure. The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure is requested qualifies under 10 CFR 2.390(a)(4) Trade secrets and commercial or financial information.

6. The following criteria are customarily applied by Framatome to determine whether information should be classified as proprietary:

(a) The information reveals details of Framatomes research and development plans and programs or their results.

(b) Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, produce, or market a similar product or service.

(c) The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for Framatome.

(d) The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for Framatome in product optimization or marketability.

(e) The information is vital to a competitive advantage held by Framatome, would be helpful to competitors to Framatome, and would likely cause substantial harm to the competitive position of Framatome.

The information in these Documents is considered proprietary for the reasons set forth in paragraphs 6(b), 6 (c), 6(d) and 6(e) above.

7. In accordance with Framatomes policies governing the protection and control of information, proprietary information contained in these Documents has been made available, on a limited basis, to others outside Framatome only as required and under suitable agreement providing for nondisclosure and limited use of the information.

8. Framatome policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.

9. The foregoing statements are true and correct to the best of my knowledge, information, and belief.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on November 19, 2020.

Philip A. Opsal

Attachment 5 Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary, Document Number 32-9321037-001 (Non-Proprietary Version)

0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY CALCULATION

SUMMARY

SHEET (CSS)

Document No. 32 - 9321037 - 001 Safety Related: Yes No Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Title Proprietary PURPOSE AND

SUMMARY

OF RESULTS:

PURPOSE:

During the P2R23 outage, a leakage was discovered at the Reactor Pressure Vessel (RPV) Instrument Nozzle 16A at Peach Bottom Atomic Power Station Unit 2 (Peach Bottom Unit 2), which is a radial nozzle extending horizontally from the cylindrical vessel shell. Per Reference [20], an EVT-1 examination performed identified a crack extending vertically downward from the 6 oclock position of the nozzle.

A half nozzle repair was designed in which portion of the existing nozzle will be severed and a replacement nozzle will be attached to the OD of the reactor pressure vessel (References [3] and [4]). The present concern is that the flaw in the remnant J-Groove weld could impact the structural integrity of the vessel. Since the hoop stress in the vessel at the J-groove weld is greater than the axial stress at the same location, the preferential direction for cracking is radial relative to the nozzle and axial relative to the vessel. Therefore, a radial-axial flaw is postulated to extend from the J-Groove weld bore through the entire J-Groove weld length up to the indication length in the RPV shell axis direction and up to the J-Groove weld depth in the original nozzle axis direction. The purpose of this analysis is to evaluate the postulated radial-axial flaw for one fuel cycle of operation.

The purpose of Revision 001 of this document is to incorporate editorial comments on the bracketing of Proprietary information.

SUMMARY

OF RESULTS:

Based on a combination of Linear Elastic Fracture Mechanics (IWB-3610 of ASME Section XI, Reference [8]) and Elastic Plastic Fracture Mechanics (ASME Code Case N-749, Reference [9] , with applicable conditions per Table 2 of Reg. Guide 1.147, Revision 19, Reference [17]), the postulated flaw in the as-left J-groove weld of nozzle N16A at Peach Bottom Unit 2 is shown to be acceptable for one fuel cycle following the P2R23 outage. Results are summarized in Section 7.0.

Note: Proprietary information in this document is indicated by bolded brackets ([ ]).

The Proprietary version of this document is 32-9321034-002.

FRAMATOME INC. PROPRIETARY This document and any information contained herein is the property of Framatome Inc. (Framatome) and is to be considered proprietary and may not be reproduced or copied in whole or in part. This document shall not be furnished to others without the express written consent of Framatome and is not to be used in any way which is or may be detrimental to Framatome. This document and any copies that may have been made must be returned to Framatome upon request.

If the computer software used herein is not the latest version per the EASI list, THE DOCUMENT CONTAINS AP 0402-01 requires that justification be provided.

ASSUMPTIONS THAT SHALL BE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: VERIFIED PRIOR TO USE CODE/VERSION/REV CODE/VERSION/REV Yes ANSYS 19.2 (Section A.6)

No Page 1 of 61

0402-01-F01 (Rev. 021, 03/12/2018)

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Review Method: Design Review (Detailed Check)

Alternate Calculation Does this document establish design or technical requirements? YES NO Does this document contain Customer Required Format? YES NO Signature Block P/R/A/M Name and Title and Pages/Sections (printed or typed) Signature LP/LR Date Prepared/Reviewed/Approved Luziana Matte LR MATTE LP All Pages/ All Sections Technical Consultant 11/19/2020 Ashok Nana AD NANA LR All Pages/ All Sections Advisory Engineer 11/19/2020 David Cofflin D KIM for DR COFFLIN A All Pages/ All Sections Supervisory Engineer 11/19/2020 Notes: P/R/A designates Preparer (P), Reviewer (R), Approver (A);

LP/LR designates Lead Preparer (LP), Lead Reviewer (LR);

M designates Mentor (M)

In preparing, reviewing and approving revisions, the lead preparer/reviewer/approver shall use All or All except

___ in the pages/sections reviewed/approved. All or All except ___ means that the changes and the effect of the changes on the entire document have been prepared/reviewed/approved. It does not mean that the lead preparer/reviewer/approver has prepared/reviewed/approved all the pages of the document.

With Approver permission, calculations may be revised without using the latest CSS form. This deviation is permitted when expediency and/or cost are a factor. Approver shall add a comment in the right-most column that acknowledges and justifies this deviation.

Project Manager Approval of Customer References and/or Customer Formatting (N/A if not applicable)

Name Title (printed or typed) (printed or typed) Signature Date Comments Alan Stalker Project Manager AR STALKER 11/19/2020 Page 2

0402-01-F01 (Rev. 021, 03/12/2018)

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Record of Revision Revision Pages/Sections/Paragraphs No. Changed Brief Description / Change Authorization Original Release (November 2020).

000 All The Proprietary version of this document is 32-9321034-001.

Incorporate editorial comments on the bracketing of 001 All Proprietary information on Table A-1 and Figure A-1.

The Proprietary version of this document is 32-9321034-002.

Page 3

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table of Contents Page SIGNATURE BLOCK ............................................................................................................................. 2 RECORD OF REVISION ....................................................................................................................... 3 LIST OF TABLES .................................................................................................................................. 6 LIST OF FIGURES ................................................................................................................................ 7 1.0 PURPOSE .................................................................................................................................. 8 2.0 ANALYTICAL METHODOLOGY............................................................................................... 12 2.1 Stress Intensity Factor Solution ...................................................................................................... 12 2.2 Fatigue and Stress Corrosion Crack Growth .................................................................................. 17 2.3 Linear Elastic Fracture Mechanics .................................................................................................. 17 2.4 Elastic Plastic Fracture Mechanics ................................................................................................. 18 2.4.1 Screening Criteria ............................................................................................................. 18 2.4.2 Flaw Stability and Crack Driving Force ............................................................................. 18 2.5 Acceptance Criteria ......................................................................................................................... 19 2.6 Primary Stress Evaluation ............................................................................................................... 20 3.0 ASSUMPTIONS ....................................................................................................................... 21 3.1 Unverified Assumptions................................................................................................................... 21 3.2 Justified Assumptions ...................................................................................................................... 21 3.3 Modeling Simplifications .................................................................................................................. 22 4.0 DESIGN INPUTS...................................................................................................................... 23 4.1 Geometry ......................................................................................................................................... 23 4.2 Materials .......................................................................................................................................... 24 4.2.1 Mechanical Properties ...................................................................................................... 24 4.2.2 Fracture Material Properties ............................................................................................. 25 4.3 Applied Stresses ............................................................................................................................. 26 4.3.1 Operating Stresses ........................................................................................................... 26 4.3.2 Weld Residual Stress ....................................................................................................... 26 4.3.3 Crack Face Pressure ........................................................................................................ 27 5.0 COMPUTER USAGE ............................................................................................................... 27 5.1 Computer Software ......................................................................................................................... 27 5.2 Computer Files ................................................................................................................................ 27 6.0 CALCULATIONS ...................................................................................................................... 28 6.1 LEFM Evaluation ............................................................................................................................. 28 6.2 EPFM Evaluation ............................................................................................................................. 28 6.3 Primary Stress Evaluation ............................................................................................................... 29 Page 4

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table of Contents (continued)

Page

7.0 CONCLUSION

S ....................................................................................................................... 30

8.0 REFERENCES

......................................................................................................................... 32 APPENDIX A : OPERATING STRESS ANALYSIS ............................................................................ 34 APPENDIX B : SIF SOLUTION TEST CASES ................................................................................... 50 APPENDIX C : FM EVALUATION RESULT TABLES ......................................................................... 53 Page 5

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary List of Tables Page Table 2-1: Structural Factors for Flaw Acceptance ............................................................................. 20 Table 4-1: Key Dimensions ................................................................................................................ 23 Table 4-2: Material Properties for Reactor Pressure Vessel ............................................................... 24 Table 4-3: Applicable Operating Transient ......................................................................................... 26 Table 5-1: Computer Files.................................................................................................................. 27 Table A-1: Material Designations........................................................................................................ 35 Table A-2: Heat Up and Cool Down ................................................................................................... 37 Table A-3: Loss of [ ] Pump, [ ]................................................... 39 Table A-4: [ ] Overpressure [ ] .......................................................... 41 Table A-5: Single Relief [ ] ....................................................................... 43 Table A-6: Column Description ........................................................................................................... 47 Table A-7: List of Computer Files for Revision 000 ............................................................................. 49 Table C-1: LEFM Results - HUCD Transient ...................................................................................... 54 Table C-2: LEFM Results - Loss of [ ] Pump Transient ................................................... 55 Table C-3: LEFM Results - [ ] Overpressure [ ] Transient ............................... 56 Table C-4: LEFM Results - Single Relief [ ] Transient ............................ 57 Table C-5: EPFM Results (Section 3.1 of CC N-749) - HUCD Transient ............................................ 58 Table C-6: EPFM Results (Section 3.1 of CC N-749) - Loss of [ ] Pump Transient ......... 59 Table C-7: EPFM Results (Section 3.1 of CC N-749) - [ ] Overpressure [

] Transient............................................................................................................. 60 Table C-8: EPFM Results (Section 3.1 of CC N-749) - Single Relief [

] Transient ....................................................................................................... 61 Page 6

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary List of Figures Page Figure 1-1: Instrumentation Nozzle N16-A - Vertical Crack Extending Down from 6 Oclock Position ............................................................................................................................... 9 Figure 1-2: Instrumentation Nozzle N16-A Repair Configuration with Temporary Nozzle Dam ........... 10 Figure 1-3: Postulated Radial-Axial Flaw Configuration ...................................................................... 11 Figure 2-1: SIF Solution Model ............................................................................................................ 13 Figure A-1: Material Assignment.......................................................................................................... 36 Figure A-2: Heat Up and Cool Down ................................................................................................... 38 Figure A-3: Loss of [ ] Pump, [ ]................................................... 40 Figure A-4: [ ] Overpressure [ ] .......................................................... 42 Figure A-5: Single Relief [ ] ....................................................................... 44 Figure A-6: Locations for Thermal Gradients ...................................................................................... 45 Figure A-7: FE Model, Crevice Boundary Conditions .......................................................................... 46 Figure A-8: Structural Run Boundary Conditions.................................................................................. 46 Figure A-9: Results, Reported Locations ............................................................................................. 47 Figure B-1: Test Case for Tension (Based on Figure 10 of [5]) ............................................................ 51 Figure B-2: Test Case for Bending (Based on Figure 11 of [5]) ............................................................ 52 Page 7

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 1.0 PURPOSE During the P2R23 outage, a leakage was discovered at the Reactor Pressure Vessel (RPV) Instrument Nozzle 16A (40° azimuth) at Peach Bottom Atomic Power Station Unit 2 (Peach Bottom Unit 2), which is a radial nozzle extending horizontally from the cylindrical vessel shell (References [1] and [2]). Per Reference [20], an EVT-1 examination performed identified a crack extending vertically downward from the 6 oclock position of the nozzle with an approximate length of [ ] from the ID of the original nozzle (Figure 1-1).

A half nozzle repair was designed in which portion of the existing nozzle will be severed and a replacement nozzle will be attached to the OD of the reactor pressure vessel (References [3] and [4]) (Figure 1-2). The present concern is that a flaw in the remnant J-Groove weld could impact the structural integrity of the vessel. Since the hoop stress in the vessel at the J-groove weld is greater than the axial stress at the same location, the preferential direction for cracking is radial relative to the nozzle and axial relative to the vessel. Therefore, since Reference

[20] does not provide measurements on the indication depth, a radial-axial flaw is postulated (consistent with and to bound the actual observed indication) to extend from the J-Groove weld bore through the entire J-Groove weld up to the indication length in the RPV shell axis direction and up to the J-Groove weld depth in the original nozzle axis direction (Figure 1-3) (Modelling Simplification listed in Section 3.3 item 2). The purpose of this analysis is to evaluate the postulated radial-axial flaw for one fuel cycle of operation.

Purpose of Revision 001 of 32-9321034 is to indicate the Proprietary information in this document by bolded brackets ([ ]).

Purpose of Revision 002 of 32-9321034 is to incorporate editorial comments on the bracketing of Proprietary information.

Page 8

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure 1-1: Instrumentation Nozzle N16-A - Vertical Crack Extending Down from 6 Oclock Position Page 9

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure 1-2: Instrumentation Nozzle N16-A Repair Configuration with Temporary Nozzle Dam Page 10

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure 1-3: Postulated Radial-Axial Flaw Configuration Page 11

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 2.0 ANALYTICAL METHODOLOGY A radial-axial flaw at the inside corner of the nozzle penetration is evaluated based on linear elastic fracture mechanics (LEFM) and elastic plastic fracture mechanics (EPFM), as outlined below.

1. Postulate an initial radial-axial flaw in the J-groove weld, extending from the J-Groove weld bore through the entire J-Groove weld up to the indication length in the RPV shell axis direction (initial flaw length c0 in Figure 1-3) and up to the J-Groove weld depth in the original nozzle axis direction (initial flaw depth a0 in Figure 1-3) (Modelling Simplification listed in Section 3.3 item 2).

2. Estimate the total flaw growth accommodating any potential crack growth into the RPV vessel wall, using

[ ] Reference [13], as a basis for the crack growth rates (CGR).

3. Calculate the applied stress intensity factors for selected limiting transients using the stress intensity factor (SIF) solution from reference [5] for the estimated final flaw sizes at the end of one fuel cycle.

4. Compare the applied stress intensity factors to the ASME Section XI code criteria of IWB-3612 and IWB-3613 (Reference [8]) as applicable.

5. Calculate the applied J-integral with appropriate safety factors as defined in Section 3.1 of ASME Code Case N-749 (Reference [9]).

6. Compare the applied J-integral to the material J-integral at a ductile crack extension of 0.1 inch, which will be based on the lower bound J-R curve in Reg. Guide 1.161 (Reference [15]).

7. If the criteria of Section 3.1 of Reference [9] are not met, the flaw may still be acceptable if the criteria of Section 3.2 of Reference [9] are met. In this case, the applied J-integral with appropriate safety factors as defined in Section 3.2 of ASME Code Case N-749 (Reference [9]) is also calculated.

8. If the criteria of Section 3.2 of ASME Code Case N-749 (Reference [9]) are required, a flaw stability analysis is also performed using a J-integral/tearing modulus (J-T) diagram to evaluate flaw stability under ductile tearing. The flaw stability is demonstrated at an applied J-integral when the applied tearing modulus is less than the material tearing modulus. Alternately, the applied J-integral is less than the J-integral at the point of instability.

9. Verify the primary stress, assuming a local area reduction of the pressure retaining membrane that is equal to the area of the flaw, meets the limits of NB-3200 rules, Reference [11], as required by IWB-3610(d)(2) (Reference [8]) and Sections 3.1(c) or 3.2(a)(3) of N-749 (Reference [9]).

Additional details on the methodology are provided in the following subsections.

2.1 Stress Intensity Factor Solution The stress intensity factor (SIF) solution for a quarter-elliptical corner crack initiating at the bore of a cylindrical penetration from Reference [5], as shown in Figure 2-1, is used in the current flaw evaluation analysis to develop the applied stress intensity factor at the crack tip.

Page 12

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure 2-1: SIF Solution Model Page 13

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary The formulas for the SIF solution as developed in Reference [5] are documented as follows:

4

+ 2

= ( + )

4 +

Where St is the membrane stress, Sb is the bending stress, a is the flaw size (nozzle axis) in the depth direction, c is the flaw size in the lateral (radial) direction, t is the plate thickness, and r is the hole radius. The final factor in the equation converts the solution for two symmetric flaws into an equation for one flaw. The remaining terms are defined below as reported in Reference [5]. The flaw evaluation in this document will be based on the depth location, which produce higher applied stress intensity values. The solution in Reference [5] was curve fitted for the range of parameters 0.2 < a/c < 2, a/t < 1, 0.5 r/t 2, (r + c)/b < 0.5, and -/2 -/2. It should be noted that the r/t ratio for the geometry analyzed in the current flaw evaluation is < 0.5. However, the Reference

[5] SIF solution still provides reasonable and conservative estimation of the crack driving force. The parameter b is the plate half width. It is used for finite width correction factor (fw equation below), which is a factor that accounts for cases where the edge of the flaw at distance "r+c" from the hole centerline in Figure 2-1 reaches near the edge of the plate at distance "b" from the hole centerline. The factor approaches 1.0 as the plate width "b" becomes large. Since the RPV is very large and the crack is not near an edge of the RPV this factor is essentially 1.0. Hence, the solution is not sensitive to the parameter b. The solution is implemented in an Excel spreadsheet.

Tests of the spreadsheet to verify the implementation of the equations are shown in Appendix B. The equations from Reference [5] are presented below:

2 4

= 1 + 2 + 3 x 1 x 2 x 3 x 4 x x 2 4

= 1 + 2 + 3 x 1 x 2 x 3 x 4 x x

= 1 + (2 1 ) x ()

2 3 1 = 1 + 11 x + 12 x + 13 x 2 3 2 = 1 + 21 x + 22 x + 23 x 0.25 2

= x ()2 + ()2 0.5 (2+)

2 x 4()+2 x , where n = 1 is for a single crack and n = 2 is for two-symmetric cracks The factor g2 is different for tension and bending loads. For tension, g2 is determined as below with =0.85 1 + 0.358 + 1.4252 1.5783 + 2.1564 2

1 + 0.132 1

=

1 + x ()

Page 14

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary For bending, g2b is determined as below 1 + 0.358 + 1.425 2 1.578 3 + 2.156 4 2 =

1 + 0.13 2 1

=

1 + x ( )

0.25

= 0.85 0.25 For a/c 1 1 = 1.13 0.09 0.89 2 = 0.54 +

0.2 +

1 24 3 = 0.5 + 14 1 0.65 +

2 1 = 1 + 0.1 + 0.35 x (1 )2 0.25 3 = 1 + 0.04 x [1 + 0.1(1 )2 ] x 0.85 + 0.15 4 = 1 0.7 1 x 0.2 1

= 0.1 + 1.3 + 1.1 0.7 2

11 = 0.43 0.74 0.84 2

12 = 1.25 1.19 + 4.39 2

13 = 1.94 + 4.22 5.51 2

21 = 1.5 0.04 1.73 2

22 = 1.71 3.17 + 6.84 2

23 = 1.28 + 2.71 5.22 1.65

= 1 + 1.464 x For a/c > 1 1 = 1 + 0.04 Page 15

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 4

2 = 0.2 4

3 = 0.11 2

1 = 1 + 0.1 + 0.35 x (1 )2 0.25 3 = 1.13 0.09 x [1 + 0.1(1 )2 ] x 0.85 + 0.15 4 = 1 11 = 2.07 + 0.06 12 = 4.35 + 0.16 13 = 2.93 0.3 21 = 3.64 + 0.37 22 = 5.87 0.49 23 = 4.32 + 0.53 1.65

= 1 + 1.464 x

= 0.2 + + 0.6 After determining the SIF value from the equations listed above, a plasticity correction is applied based on the Irwin plastic zone correction. The Irwin plastic zone correction is discussed in Reference [6]. The effective crack depth is defined as the sum of the actual crack size and the plastic zone correction:

= +

Where ry for plane strain conditions the correction is (Reference [6], Eq. 2.63):

2 1

=

6 Where ys is the yield strength of the material and KI is the stress intensity factor at the actual crack size (depth a and length c). The plastic zone correction is applied to the flaw length, c, using the applied KI at the surface point

(=0°), and to the flaw depth, a, using the applied KI at the deepest point (=90°). An effective stress intensity factor (KIeff) is calculated by first calculating KI based on flaw size a and c. Then the size of the plastic zone at a and c (ry at =90° and =0°) is calculated based on KI at =90° and =0°, respectively. Then the KIeff is determined by recalculating KI utilizing the flaw dimension a + ry (=90°) and c + ry (=0°) in place of a and c, respectively.

Page 16

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 2.2 Fatigue and Stress Corrosion Crack Growth Flaw growth in the low alloy steel is driven by fatigue crack growth and intergranular stress corrosion cracking (IGSCC). Since the current analysis considers only one fuel cycle of plant operation, fatigue crack growth will be minimal.

The analysis conservatively postulates that a flaw extends through the entire J-groove weld. [

]

For one fuel cycle of operation [ ] the total [ ] growth is equal to

[ ] The postulated flaw depth and length conservatively assumes a total flaw growth of [ ] which provides sufficient margin to accommodate any potential crack growth.

2.3 Linear Elastic Fracture Mechanics Linear Elastic Fracture Mechanics (LEFM) acceptance criteria are based on the criteria of IWB-3600 of Reference [8]. Article IWB-3612 of Section XI requires that the applied stress intensity factor be less than the available fracture toughness at the crack tip temperature, with appropriate safety factor, as outlined below.

IWB-3613(a): For conditions where pressurization does not exceed 20% of the design pressure (design pressure is [ ] Reference [2]) during which the minimum temperature is not less than RTNDT:

KI < KIc /2 IWB-3613(b): For Normal and Upset conditions excluding those described in IWB-3613(a):

Page 17

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary KI < KIc /10 (criteria of IWB-3612(a))

IWB-3613(c): For Emergency and Faulted conditions:

KI < KIc /2 (criteria of IWB-3612(b))

In the above, KIc is the fracture toughness based on crack initiation defined in A-4200(b) of Reference [8].

2.4 Elastic Plastic Fracture Mechanics The Elastic Plastic Fracture Mechanics (EPFM) analysis uses ASME Code Case N-749 (Reference [9]). The methodology is described in the following subsections.

2.4.1 Screening Criteria ASME Code Case N-749 states that EPFM acceptance criteria are applicable to ferritic steel components on the upper shelf of the Charpy energy curve when the metal temperature exceeds the upper shelf transition temperature, Tc. The NRC has proposed a modification to the Code Case definition of Tc (Reference [10]), which is considered for this analysis and defined below

= 154.8 + 0.82 x (U.S. Customary Units)

Where RTNDT is the adjusted reference nilductility temperature as described in Section 4.2.2. When the metal temperature exceeds Tc, EPFM analysis is applicable. Additionally, NRC defines in RG 1.147 draft rev. 19 (Reference [17]), a temperature Tc1 below which the LEFM method must be applied:

1 = 95.36 + 0.703 x (U.S. Customary Units)

Per Reference [17], between Tc1 and Tc, while the fracture mode is in transition from LEFM to EPFM, users should consider whether or not it is appropriate to apply the EPFM method.

2.4.2 Flaw Stability and Crack Driving Force Elastic-plastic fracture mechanics analysis will be performed based on ASME Code Case N-749 (Reference [9])

to evaluate crack driving force and flaw stability (if applicable). Two possible sets of acceptance criteria for EPFM are defined in Code Case N-749:

• Section 3.1 Acceptance Criteria Based Solely on Limited Ductile Crack Extension, or

• Section 3.2 Acceptance Criteria Based on Limited Ductile Crack Extension and Stability.

Section 3.1 of Reference [9] states that the flaw is acceptable if the crack driving force, as measured by the applied J-integral (Japp) with appropriate structural factors applied to the loads, is less than the J-integral of the material (Jmat) at a ductile crack extension of 0.1 inch (J0.1). If the criteria of Section 3.1 of Reference [9] are not met, the flaw may still be acceptable if the criteria of Section 3.2 of Reference [9] are met. Section 3.2 allows lower safety factors for the crack driving force check, and additionally requires that flaw stability be evaluated with appropriate safety factors.

If applicable, the flaw stability analysis is performed using a J-integral/tearing modulus (J-T) diagram to evaluate flaw stability under ductile tearing, where J is either the applied (Japp) or the material (Jmat) J-integral, and T is the tearing modulus, defined as (E/f2)x(J/a). Flaw stability and crack driving force assessments utilizes the safety factors from Code Case N-749 as outlined in Table 2-1.

Page 18

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary The general methodology for performing an EPFM analyses is outlined below.

E = E/(1-2)

KI due to pressure (primary) = KIp KI due to thermal loads (secondary) = KIs Safety factor on primary loads = SFp Safety factor on secondary loads = SFs Total applied KI with safety factors, KIeff = SFp x KIp + SFs x KIs Where E and are the modulus of elasticity and Poissons ratio, as specified in Section 4.2.1.

For this analysis the crack driving force, J, is estimated based on small scale yielding as described below. The stress intensity factors due to primary stresses (KIp) and the stress intensity factors due to secondary stresses (KIs) are calculated using the method described in Section 2.1, including the plastic zone correction, which is applied prior to application of structural factors per Section 4.1 of Reference [9]. Per Sections 2(c) of Reference [9],

residual stresses do not need to be included in the EPFM analysis.

The applied J-integral is then calculated using the following relationship:

2

=

The applied J-integral is checked against J0.1, demonstrating that the crack driving force falls below the J-R curve at a crack extension of 0.1 inch, per Section 3.1 of Reference [9].

If applicable, for flaw stability analysis (i.e., Section 3.2 of Reference [9]), the final parameter needed to construct the J-T diagram is the tearing modulus. The applied tearing modulus, Tapp, is calculated by numerical differentiation for small increments of crack size (da) about the crack size (a), according to

( + ) ( )

=

2 2 Where f is the flow stress defined as f = 1/2(y + u), where y is the yield strength and u is the ultimate tensile strength, as specified in Section 4.2.1.

The J-integral resistance (J-R) curve, needed for the EPFM method of analysis, is described in Section 4.2.2. The flaw stability is demonstrated at an applied J-integral when the applied tearing modulus is less than the material tearing modulus. Alternately, the applied J-integral is less than the J-integral at the point of instability.

2.5 Acceptance Criteria The applicable code is ASME Section XI, 2013 Edition (Reference [8]). If the service life of the component is shown to be limited, an alternate approach of using ASME Section XI Code Case N-749 (Reference [9]) as modified by the Nuclear Regulatory Commission (Reference [10]) will be considered in the evaluation.

Acceptance of each postulated flaw is determined based on available fracture toughness or ductile tearing resistance using the safety factors outlined in Table 2-1.

Page 19

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table 2-1: Structural Factors for Flaw Acceptance LEFM(1)

Operating Condition Evaluation Method Fracture Toughness / KI Normal/Upset KIc fracture toughness 10 = 3.16 or 2 = 1.41(1a, 1b)

Emergency/Faulted KIc fracture toughness 2 = 1.41(1c)

EPFM Based on Limited Ductile Flaw Extension(2)

Operating Condition Evaluation Method Primary Secondary Normal/Upset J0.1 limited flaw extension 2.0 1.0 Emergency/Faulted J0.1 limited flaw extension 1.5 1.0 EPFM Based on Limited Ductile Flaw Extension and Stability(3)

Operating Condition Evaluation Method Primary Secondary Normal/Upset J/T based flaw stability 2.14 1.0 Normal/Upset J0.1 limited flaw extension 1.5 1.0 Emergency/Faulted J/T based flaw stability 1.2 1.0 Emergency/Faulted J0.1 limited flaw extension 1.25 1.0 Notes:

(1) LEFM safety factors are from IWB-3613 of ASME Section XI (Reference [8]).

a. Per IWB-3613(a), for conditions where pressurization does not exceed 20%

of the design pressure during which the minimum temperature is not less than RTNDT:

KI < KIc /2

b. Per IWB-3613(b), for Normal and Upset conditions excluding those described in IWB-3613(a):

KI < KIc /10 (criteria of IWB-3612(a))

c. Per IWB-3613(c), for Emergency and Faulted conditions:

KI < KIc /2 (criteria of IWB-3612(b))

(2) EPFM safety factors based on Section 3.1 of Code Case N-749 (Reference [9]).

(3) EPFM safety factors based on Section 3.2 of Code Case N-749 (Reference [9]).

2.6 Primary Stress Evaluation IWB-3610(d)(2) of Reference [8] and Items 3.1(c) and 3.2(a)(3) of Reference [9] state that the flawed component must meet the primary stress limits of NB-3200, Reference [11], assuming a local area reduction of the pressure retaining membrane that is equal to the area of the flaw. For this evaluation, this check will be performed by confirming that the area of the flaw and any existing material removed by the modification are balanced by metal added by the weld pad, new J-groove weld, and fillet. Appropriate adjustments for difference in strengths of materials are made per the rules of NB-3336 (Reference [11]).

Page 20

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 3.0 ASSUMPTIONS 3.1 Unverified Assumptions There are no unverified assumptions used in this calculation.

3.2 Justified Assumptions The following justified assumptions are used in this analysis:

1. Based on review of the stress-strain curves for [ ] in Reference [12], there is assumed to be a uniform weld residual stress of [ ] (slightly above room temperature yield) over the depth of the J-groove weld, which is balanced by a uniform compressive stress over the remaining thickness. This assumed stress distribution is then converted to an equivalent bending stress for use in the SIF solution described in Section 2.1. The equivalent bending stress Sb (estimated based on a local stress distribution) is applied as a remote stress, and would then be amplified by stress concentration effects accounted for in the SIF solution.

This analysis simplifies the weld residual stress by constant stress with magnitude of [ ] over the whole cross section of the weld. Such simplification, although considered reasonable, is impossible to prove or disprove without detailed weld residual stress analysis which is far beyond the scope and time frame allowed by this OCJ.

Page 21

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Additional justified assumptions and modelling simplifications are listed in Section A.3 of Appendix A.

3.3 Modeling Simplifications The following modeling simplifications are used in this analysis:

1. The SIF solution used (Section 2.1) is based on a corner flaw in a flat plate with a hole under remote uniaxial tension and bending stresses. This is a conservative simplification since the stress concentration at a hole is higher with uniaxial tension than with biaxial tension. The ratio of the hole radius to plate thickness, r/t is < 0.5, however the SIF solution of Reference [5] still provides a reasonable and conservative estimation of the crack driving force.

2. Two options were investigated to determine the more appropriate initial flaw length, co, and the bore radius, r, of the postulated flaw. The first option would be to utilize the initial flaw length as the indication length of [ ] and the bore radius as the original nozzle internal radius of

[ ] (Table 4-1). The second option utilizes the initial flaw length as the indication length minus the original nozzle thickness [ ] (Table 4-1) and the bore radius as the J-Groove bore radius of [ ] The second option yields higher stress intensity factor values and is considered appropriate for use in this evaluation.

Page 22

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 4.0 DESIGN INPUTS 4.1 Geometry The original geometry is described in References [1] and [3], with the half nozzle repair design shown in Reference [3]. The reactor pressure vessel and the instrumentation nozzle 16A are described by the following key dimensions:

Table 4-1: Key Dimensions Dimension Value Reference Radius to Base Metal [ ] [3]

Reactor Vessel Wall Thickness (min) [ ] [3]

Cladding thickness [ ] [1] (note 2)

Inside Diameter of Original Nozzle [ ] [3]

Outside Diameter of Original Nozzle [ ] [3]

Depth of J-groove Weld (from cladding) [ ] [1] (note 2)

Width of J-Groove Weld [ ] [1] (note 2)

Diameter of Bore at J-Groove Weld [ ] [3]

Original Nozzle Thickness [ ] [3]

Note(s):

(1): Width of the J-groove weld is calculated as:

[ ]

(2): Drawing No. [ ] , listed in Reference [1].

(3): [ ]

Per Reference [20], the vertical indication length is approximately [ ] from the ID of the original nozzle.

Therefore, at the end of one fuel cycle, the postulated flaw length is taken as the indication length of [ ]

(Reference [20]), minus the original nozzle thickness, plus the estimated total crack growth of [ ] (see Section 2.2).

The postulated flaw depth at the end of one fuel cycle is taken as the total depth of the J-groove weld, plus the estimated total crack growth of [ ] (see Section 2.2). This results in a flaw depth, a =

[ ] and flaw length, c = [ ]

The thickness and the J-groove bore radius considered for the SIF solution is [

] and [ ] respectively.

Page 23

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 4.2 Materials The materials used in the design are summarized below:

RV Shell SA-302 Gr. B modified [ ] Reference [4]

Existing J-Groove Weld [ ] Reference [3]

Existing Nozzle [ ] Reference [4]

Replacement Nozzle [ ] UNS N06690 (Alloy 690) Reference [4]

Repair Weld and Nozzle to Weld Pad Weld ERNiCrFe-7A, UNS N066054, (Alloy 52M) Reference [4]

4.2.1 Mechanical Properties The reactor pressure vessel shell analyzed is made of SA-302 Grade B modified [ ]

Reference [4]. Table 4-2 lists the temperature dependent values of modulus of elasticity (E), Poissons ratio (),

yield strength (y), and ultimate strength (u). These properties are obtained from References [14] and Reference

[26] for the existing materials and Reference [23] for the modification materials, except for Poissons ratio, where 0.3 is a typical value used in structural analysis.

Table 4-2: Material Properties for Reactor Pressure Vessel Component Reactor Pressure Vessel Material SA-302 Grade B modified Temperature E(1) y(1) [ u(1)

[°F] [106 psi] [ksi] ] [ksi]

70 29.9 0.30 50.0 [ ] 80.0 100 29.8 0.30 50.0 [ ] ---

200 29.5 0.30 47.2 [ ] ---

300 29.0 0.30 45.3 [ ] ---

400 28.6 0.30 44.5 [ ] ---

500 28.0 0.30 43.2 [ ] ---

600 27.4 0.30 42.0 [ ] ---

Notes:

(1): Per Reference [14].

(2): [

]

[ ] Per References [14] and

[23], at a representative temperature of 550°F, the design stress intensity, Sm, for [ ] and Alloy 690 is

[ ] and the Sm for the SA-302 Grade B modified base metal is [ ]

Page 24

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 4.2.2 Fracture Material Properties Per Reference [19], the 54 EFPY adjusted reference nilductility temperature RTNDT (ART) of the limiting material for the lower intermediate RV shell [ ] is [ ] and is conservatively considered for this analysis although the EFPY at the end of one-fuel cycle following the P2R23 outage is much lower (EFPY at the end of the P2R23 outage is [ ] per Reference [18]) (Justified Assumption listed in Section 3.2, item 5). This value of RTNDT is utilized with the KIc fracture toughness for crack initiation curve defined in Article A-4200 of Section XI (Reference [8]) as:

= 33.2 + 20.734 exp[0.02( )]

Where T is the crack tip temperature, KIc is in units of ksiin, and T and RTNDT are in units of °F. In the present calculations, KIc is limited to a maximum value of 200 ksiin (upper-shelf fracture toughness). The crack initiation KIc upper shelf toughness of 200 ksiin is achieved at T-RTNDT > [ ]

The J-integral resistance (J-R) curve, needed for the EPFM method of analysis, is obtained from the following correlation for reactor pressure vessel plate in Regulatory Guide 1.161, Section 3.3.1 (Reference [15]):

= {1 ()2 (3 ()4 ) }

Where MF is a margin factor, and a is the crack extension. C1, C2, C3, and C4 are coefficients which depend on the crack tip temperature and the Charpy V-notch upper-shelf energy as defined below:

1 = (2.44 + 1.13 () 0.00277) 2 = 0.077 + 0.116 1 3 = 0.0812 0.0092 1 4 = 0.409 Where CVN is the Charpy V-notch upper-shelf energy in ft-lbs, and T is the crack tip temperature in °F. The margin factor, MF, of 0.749 is utilized for the analysis for all cases, which provides a conservative J-R curve as required by Reference [9]. Section 3.3.1 of Reference [15] states that the use of this model should be justified if the sulfur content of the plate is greater than 0.018 wt.%. Per Reference [2], the nozzle 16A is located in a section of shell course 2 with plate heat number [ ] Per Reference [18], plate [ ] has a sulfur content of [ ] and, therefore, the use of this model is applicable.

The actual Charpy V-notch upper shelf energy values in the longitudinal and transverse directions after one fuel cycle following the P2R23 outage (EFPY at the end of the P2R23 outage is [ ] , Reference [18]) are not available. However, Reference [1] state that an equivalent margin analysis (EMA) was performed at 53 EFPY and approved by the NRC which confirms that the Charpy V-notch upper-shelf energy (CVN) is greater than

[ ] Therefore, a CVN of [ ] is conservatively assumed in both the longitudinal and transverse directions for the one-cycle justification (Justified Assumption Section 3.2, item 2).

Page 25

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 4.3 Applied Stresses 4.3.1 Operating Stresses An axisymmetric finite element model is developed to generate transient stress results and is documented in Appendix A. The transients defined in Reference [1] are reviewed and the bounding transients are selected based on pressure and temperature ranges. Transient stress analyses are performed for the bounding design transients listed in Table 4-3, which are described in more detail in Appendix A:

Table 4-3: Applicable Operating Transient Transient Name Condition ID

[ ] Normal/Upset HUCD

[ ] Normal/Upset Loss of Pump

[

Emergency/Faulted Overpressure

]

[ ] Normal/Upset Single Relief Note (1): Applicable transients and conditions are defined in Reference [21].

The linearized through wall bending hoop stresses are taken from the finite element output for the path line NearPath through the RV shell, and contribute to the remote applied bending stress, Sb, used for the SIF solution. Since the finite element model uses an equivalent sphere with a radius of 2.5 times the actual radius, the membrane stresses are overly conservative, and thus the remote tensile stress, St, applied for the SIF solution is calculated using the basic hoop stress formula, pRi/t, where p is the pressure, Ri is the inside radius

[ ] and t is the thickness [ ]

4.3.2 Weld Residual Stress As noted in Section 3.2, item 1 it is assumed that the weld residual stress over the depth of the J-groove weld into the base metal, d = [ ] (Section 4.1) is at a uniform tensile stress of [ ] which is balanced by a uniform stress over the remainder of the total thickness [ ] such that the compressive stress is given by This stress distribution has a net tensile stress, St, of 0 ksi. The equivalent remote bending stress, Sb, is defined by Page 26

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 4.3.3 Crack Face Pressure Crack face pressure loading is accounted for in a similar manner to the welding residual stress. A uniform tensile stress equal to the applied pressure is considered over the crack depth, [ ] (Section 4.1). The stress over the remaining thickness is equal to zero. The equivalent remote tensile load is given by The equivalent bending stress for the postulated flaw depth is defined by 5.0 COMPUTER USAGE 5.1 Computer Software The calculations in the main body of this report are performed using Microsoft Excel spreadsheets.

Documentation of the ANSYS (Reference [16]) runs reported in Appendix A are provided in that appendix.

5.2 Computer Files The excel spreadsheet utilized for the fracture mechanics analysis is listed in Table 5-1 stored in ColdStor at the location listed below.

\cold\General-Access\32\32-9000000\32-9321034-000\official Table 5-1: Computer Files CRC Checksum Size (Bytes) Modified Date Time File Name 01269 418417 Nov 14 2020 11:09:47 PeachBottom2_N16A_LEFM_EPFM_v1.xlsm Page 27

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 6.0 CALCULATIONS 6.1 LEFM Evaluation Applied stress intensity factors are calculated using the SIF solution from Section 2.1 and the various sources of stresses described in Section 4.3. The SIFs including plastic zone correction were calculated using the spreadsheet PeachBottom2_N16A_LEFM_EPFM_v1.xlsm (see Table 5-1) at both the =0° and =90° locations and compared to the acceptance criteria described in Sections 2.3 and 2.5. The KIc values shown in Table C-1 through Table C-4 are calculated using a temperature equal to the minimum of the metal temperature and the fluid temperature. For normal and upset conditions below a pressure of [ ] the criteria of IWB-3613(a) is considered such that the required margin is 2.

The upper shelf transition temperature, Tc defined in Section 2.4.1, above which the EPFM must be applied is calculated as follows:

= 154.8 + 0.82 x = 154.8 + 0.82 x [ ]

The additional temperature limit defined in RG 1.147 draft rev. 19 (Reference [17]), Tc1 below which the LEFM method must be applied is calculated as follows 1 = 95.36 + 0.703 x = 95.36 + 0.703 x [ ]

The results documented in Table C-1 through Table C-4 show that the Emergency and Faulted conditions transient satisfies the required LEFM margins in all cases. For the Normal and Upset conditions the low temperature/pressure cases satisfy the required LEFM margin. All cases which do not satisfy LEFM criteria are above the upper shelf transition temperature, Tc. Therefore, the EPFM method of analysis is applicable, and the results of that analysis are documented in Section 6.2.

Table C-1 through Table C-4 also show that LEFM requirements are met for all cases where the temperature conditions fall between Tc1 and Tc, in which the fracture mode is in transition from LEFM to EPFM. Additionally, these cases are also evaluated for the EPFM method of analysis in Section 6.2.

6.2 EPFM Evaluation The EPFM analysis is performed in the spreadsheet PeachBottom2_N16A_LEFM_EPFM_v1.xlsm (see Table 5-1) using the methodology described in Section 2.4. The same stresses used in Section 6.1 are used for the EPFM analysis, however, residual stresses are removed per Section 2(c) of code case N-749, Reference [9].

As noted in Section 4.3.1, the finite element model bending stresses are considered as secondary for the EPFM analysis. Although the Emergency and Faulted conditions satisfy the LEFM criteria, the EPFM evaluation is also performed for cases in the temperature range where EPFM (T > Tc) is applicable and for cases in the temperature range where fracture mode is in transition from LEFM to EPFM (Tc1 T Tc).

Table C-5 through Table C-8 provide the results of the EPFM evaluations for the postulated flaw size using Section 3.1 of Code Case N-749 (Reference [9]). Results are shown with J0.1 values using the assumed CVN of

[ ] in both the longitudinal and transverse directions. The results are shown to be acceptable to the criteria of Section 3.1 of Code Case N-749 for all cases.

Page 28

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary 6.3 Primary Stress Evaluation Primary stresses are evaluated as described in Section 2.6, by showing that the repair configuration adds sufficient amount of cross-sectional area to account for the reduction in cross-sectional area equal to the area of the postulated flaw. All areas calculated in the following lines are for one side of the symmetric configuration.

The area of the postulated J-groove flaw including the crack growth is calculated as the area of the trapezoid, with height equal to the flaw depth, a, base equal to the flaw length, c, and the weld prep angle of [ ] (Reference

[1]).

Flaw Depth with crack growth, a = [ ] in Flaw Length with crack growth, c = [ ] in J-Groove Angle = [ ] ° Postulated Flaw Area, A1 = [ ] = [ ] in2 The repair configuration adds material by the new Alloy 52M weld pad, J-groove weld, and fillet. The repair also exposes the low alloy steel to the reactor coolant, and per Reference [7] a corrosion rate of [

] is applicable. For the calculation, the area removed from the low alloy steel will be increased by the ratio of Sm for SA-302 Gr. B to Alloy 690 and [ ] in order to account for the difference in strength per NB-3336 (Reference [11]).

Based on Reference [3], the area of Alloy 52M weld added by the repair pad, J-groove weld, and fillet is calculated as Pad Diameter (Min), D1 = [ ] in Nozzle Contigency Oversize Bore Diameter (Max), D2 = [ ] in Pad Diameter (Max), D3 = [ ] in Pad Thickness (Min), t1 = [ ] in J-Groove Fillet Size, t2 = [ ] in Pad + Fillet Area, A2 = (D1-D2)/2xt1+0.5xt2^2 + (D3-D1)/2 x t1/2= [ ] in2 The low alloy steel area lost due the replacement nozzle bore and 20 years (conservatively used in lieu of the 2 years considered in the calculation) of corrosion is calculated as follows:

Max Contigency Oversize Bore Diameter, D2 = [ ] in Original Bore Diameter, D4 = [ ] in Conservative Max Bore Depth, L1 = [ ] in Bore Area Removed, A3 = (D2-D4)/2xL1 = [ ] in2 Conservative Exposed LAS Length, L2 = [ ] in Radial Corrosion Loss, R1 = [ ] x 20 years [ ] in Corrosion Area Removed, A4= L2xR1 = [ ] in2 Total LAS Area Removed, (A3+A4) = [ ] in2 Sm(SA-302)/Sm(Alloy 690) = [ ]

Effective LAS Area Removed, A5 = [ ] x(A3+A4) = [ ] in2 The net area of the repair is calculated as follows:

Effective Area of the Repair, A6 = (A2 - A5 - A1) = [ ] in2 Page 29

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Since the net area added by the repair exceeds the area of the postulated flaw (A6 = [ ] > A1 =

[ ] ), the primary stress criteria of IWB-3610(d)(2) of Reference [8] and Sections 3.1(c) or 3.2(a)(3) of Reference [9] are considered to be satisfied for one fuel cycle.

7.0 CONCLUSION

S Based on a combination of Linear Elastic Fracture Mechanics (IWB-3610 of ASME Section XI, Reference [8])

and Elastic Plastic Fracture Mechanics (ASME Code Case N-749, Reference [9], with applicable conditions per Table 2 of Reg. Guide 1.147, Revision 19, Reference [17]) evaluations, the postulated flaw in the as-left J-groove weld of nozzle 16A at Peach Bottom Unit 2 is shown to be acceptable for one fuel cycle following the P2R23 outage.

For temperatures below the upper shelf temperature, Tc, the LEFM analysis based on IWB-3610 (Reference [8])

criteria is applicable and the limiting cases are summarized below from Table C-1 through Table C-4:

Single Relief Transient HUCD

[ ]

Service Level Normal/Upset Normal/Upset Pressure (psig) [ ] [ ]

Temperature (°F) [ ] [ ]

KIeff (ksiin) [ ] [ ]

KIc (ksiin) [ ] [ ]

Margin, KIc/KIeff [ ] [ ]

Required Margin [ ] [ ]

Acceptable By LEFM? Yes Yes For temperatures above the upper shelf temperature, Tc, and for temperatures between Tc1 and Tc, in which the fracture mode is in transition from LEFM to EPFM per RG 1.147, Reference [17], the EPFM analysis based on Section 3.1 or 3.2 of the Code Case N-749 (Reference [9]) criteria is applicable and the limiting cases are summarized below from Table C-5 through Table C-8:

Loss of [ ]

Transient [ ] Overpressure Pumps [ ]

Service Level Normal/Upset Emergency/Faulted Pressure (psig) [ ] [ ]

Temperature (°F) [ ] [ ]

CVN USE (ft-lbs) [ ] [ ]

Applied J-Integral Check Japp (kips/in) [ ] [ ]

J0.1 (kips/in) [ ] [ ]

Margin, Japp/J0.1 [ ] [ ]

Required Margin [ ] [ ]

Applied J-Integral Check Acceptable? Yes Yes Stability Check Required? No No Page 30

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary The primary stress criteria of IWB-3610(d)(2) of Reference [8] and Section 3.1(c) or 3.2(a)(3) of Reference [9]

are satisfied for one fuel cycle since the net area added by the repair exceeds the area of the postulated flaw as demonstrated in Section 6.3.

Page 31

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary

8.0 REFERENCES

References identified with an (*) are maintained within Exelon Records System and are not retrievable from Framatome Records Management. These are acceptable references per Framatome Administrative Procedure 0402-01, Attachment 7.

See page 3 for Project Manager Approval of customer references.

1. [

]

2. [

]

3. [

]

4. [

]

5. Newman, JC and Raju, IS, Stress-Intensity Factor Equations for Cracks in Three-Dimensional Finite Bodies Subjected to Tension and Bending Loads, NASA Technical Memorandum 85793.

6. T.L. Anderson, Fracture Mechanics: Fundamentals and Applications, CRC Press, 1991.

7. [

]

8. ASME Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Division 1, 2013 Edition.

9. Cases of the ASME Boiler and Pressure Vessel Code, Case N-749, Alternative Acceptance Criteria for Flaws in Ferritic Steel Components Operating in the Upper Shelf Temperature Range,Section XI, Division I.

10. Federal Register, Volume 81, Page 10787 (81 FR 10787), Wednesday March 2, 2016, Proposed Rules.

11. ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Facility Components, Division 1, 2013 Edition.

12. [

]

13. * [

]

14. ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Vessels, 1965 Edition with 1965 Winter Addenda.

15. US NRC Regulatory Guide 1.161, Evaluation of Reactor Pressure Vessels with Charpy Upper-Shelf Energy Less than 50 ft-lb, June 1995.

16. ANSYS Finite Element Computer Code, Version 19.2, ANSYS Inc., Canonsburg, PA.

17. DRAFT Regulatory Guide DG-1342, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, Proposed Revision 19 of Regulatory Guide 1.147, dated August 2018 (ADAMS No.

ML18114A225).

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary

18. [

]

19. Peach Bottom Atomic Power Station Units 2 and 3, Revision 26 to Updated Final Safety Analysis Report, Section 4.0, Reactor Coolant System, Part 1 of 2, dated April 2017 (ADAMS No. ML17130A222).

20. * [

]

21. [

]

22. [ ]

23. ASME Boiler and Pressure Vessel Code,Section II, Part D, Materials - Properties, 2013 Edition.

24. [

]

25. [

]

26. [

]

27. [

]

28 U.S. NRC Regulatory Guide 1.99, Revision 2 Radiation Embrittlement of Reactor Vessel Materials Page 33

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary APPENDIX A: OPERATING STRESS ANALYSIS A.1 Purpose This appendix (Appendix A) is to describe development of the finite element (FE) model, the loads applied to FE model, and extracting stresses to support the fracture mechanics analysis presented in the main body of this document. Note that this appendix contains both Framatome/Babcock & Wilcox and Exelon/General Electric proprietary information.

A.2 Methodology The methodology consists of:

1. Building an axially symmetric FE model which includes a section of the RV base material, a section of the original nozzle, the original J-groove weld, cladding, the new replacement nozzle, weld build-up and weld between replacement nozzle and weld build-up. The radius of the RV in the FE axi-symmetrical model was magnified for conservatism by 2.5 to account for difference in the membrane stresses between a sphere and cylinder of the same thickness and radius. There are two models with identical mesh: one for the thermal analysis and one for the structural analysis.

2. Applying the temperature and heat transfer coefficient of applicable transients for normal/upset (Heat Up/

Cool Down, Loss of [ ] Pump [ ] and Single Relief [

Safety Valve Blowdown), ] and emergency/faulted ( [ ] Overpressure [

] ) conditions on the thermal FE model.

3. Defining the locations of interest for thermal gradients within the structure, obtaining values of thermal gradients for entire transient from runs on thermal model, and selecting the time points for structural runs.

4. Applying pressure and temperature on the structural model for the time points identified in the previous step to obtain stresses resulting from pressure and thermal gradients.

5. Defining two (2) stress classification lines across the thickness of the RV, one is near the nozzle opening; the second is away from discontinuity. Listing stress components at these stress classification path lines to support fracture mechanics analysis.

A.3 Assumptions and Modeling Simplifications

1. There are no unverified assumptions used within this appendix. Justified assumptions and modeling simplifications are detailed as follows.

2. Axially symmetric model is used to calculate result stresses. In order to account for difference in membrane and bending stresses of the cylindrical shell and spherical shell of the same radius and the wall thickness, the radius of the shell was magnified for conservatism by factor of 2.5. This value is based on experience with modeling similar geometries.

3. Geometry of the replacement nozzle is approximate. The inner radius of new nozzle is equal to inner radius of the original nozzle. Such approximation is acceptable since the area of interest is in the shell, far from the nozzle-to-weld pad weld.

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary

4. Heat transfer coefficient inside shell is set to [ ] inside nozzle is set to

[ ] These values are based on stress report values (document [

] reference [1]). It is recognized that these values are applicable to the Feedwater Nozzle which is relatively distant from the instrumentation nozzle N16A, but is located in approximately the same flow conditions as feedwater nozzle, therefore the inside shell film coefficient can be used. The insulated surfaces of the nozzle and RV shell use film coefficient of [ ] Although other values can be justified, the difference is deemed insignificant for the purpose of this analysis, which is to provide stresses in the RV shell relatively far from the nozzle opening.

5. [

]

6. No external piping loads are considered in this appendix.

A.4 Design Inputs The geometry of the model is based in part on information obtained from page A-55 (stress report

[ ] reference [1]) and in part on drawing [ ] Shell Segment, drawing of nozzle repair, reference drawing [3], and reference drawing [22].

The thickness of the replacement nozzle and weld to new buildup in FE model is approximate. The difference between modeled and actual geometry is considered insignificant for the stresses in the section of the RV used for fracture mechanics analysis.

Material properties designation is based on reference drawing [3]. Reactor vessel shell is formed of SA-302 Grade B plates (nominal chemical composition Mn-1/2Mo) with inner surface cladded by stainless steel

[ ] cladding (nominal chemical composition [ ] ). The new weld pad buildup, repair nozzle and j-groove weld between repair nozzle and weld pad buildup are all of Inconel 690. These material designations can be found in Table A-1.

Table A-1: Material Designations Item Material Designation Reference Reactor Vessel, Base Material SA-302 Grade B Reactor Vessel, Cladding [ ]

Original Nozzle [ ]

Original J-groove Weld [ ] [3]

[22]

Repair Nozzle [ ] UNS N06690 (Alloy 690)

J-groove Weld to Repair Nozzle Alloy 52M (Alloy 690)

Weld Pad Build Up Alloy 52M (Alloy 690)

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure A-1: Material Assignment Opening Replacement Nozzle Centerline [

]Alloy 690 J-Weld Alloy 690 Reactor Vessel Weld Build-up SA-302 Grade B Alloy 690 Original J-Weld Original Nozzle [ ] Cladding

[ ] [ ]

A.4.1 Design Conditions Design conditions: pressure [ ] temperature [ ] ( [

] reference [1]).

A.4.2 Transient Definitions Reference [18] is used extensively within this section. Unless stated otherwise, it is always pointing to drawing

[ ] of reference [18] with MUR temperature and pressure updates defined in

[ ] reference [1]. Such notation is used for better readability. Service levels are defined in TODI, Reference [21]. Four transients were considered in this evaluation:

1. HeatCool: [

] This transient is designated as Normal/Upset Condition.

2. LossPmN: [

] This transient is designated as Normal/Upset Condition.

Note: transient with same name can be found in [ ] of reference [18], [

] This transient was investigated but the results presented in the main body of this document use stresses developed from LossPmN transient of reference [27].

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary

3. OverPress: [

] This transient is designated as Emergency/Faulted Condition.

4. SingRelf: [

] This transient is designated as Normal/Upset Condition.

A heat transfer coefficient of [ ] is used on the RV shell inner surface, values of heat transfer coefficient of [ ] at the nozzle inner surface, and [ ] for the insulated condition on the model outer surfaces are considered appropriate in this location (see Section A.3).

Table A-2: Heat Up and Cool Down Time Temperature Time Pressure

[hour] [°F] [hour] [psi]

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure A-2: Heat Up and Cool Down Page 38

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table A-3: Loss of [ ] Pump, [ ]

Time Temperature Time Pressure

[hour] [°F] [hour] [psi]

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure A-3: Loss of [ ] Pump, [ ]

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table A-4: [ ] Overpressure [ ]

Time Temperature Time Pressure

[hour] [°F] [hour] [psi]

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure A-4: [ ] Overpressure [ ]

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table A-5: Single Relief [ ]

Time Temperature Time Pressure

[hour] [°F] [hour] [psi]

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure A-5: Single Relief [ ]

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary A.5 Calculations Finite Element Model: The axially symmetric finite element model was built in ANSYS R19.2. The dimensions of the replacement nozzle are approximate.

A.5.1 Thermal Analysis The temperatures listed in Table A-2 through Table A-5 were applied on all wetted surfaces. The outer surfaces of the replacement nozzle and the part of original nozzle inserted into the RV were thermally coupled with the inner surfaces of the opening bore. Input data for transient thermal analyses are listed in Section A.4.2. The thermal runs are documented in computer output files with names *_thRun.out.

A.5.2 Structural Analysis The time-points for structural runs were selected based on the pressure transients (listed in Table A-2 through Table A-5) and thermal gradients (temperature differences) between locations of interest. The approximate location for thermal gradients can be found on Figure A-6. The thermal gradient listing can be found in computer files *_dT.out.

A list of time-points for which the structural runs were submitted can be found in the downstream calculations (Table C-1 through Table C-8 in Appendix C of this document). The pressure was applied on all wetted surfaces, including outer surface of original nozzle and inner surface of shell hole Figure A-8 (also shown on Figure A-7).

Nodes on the outer edge of the shell were fixed in hoop direction, the cap force was applied for all structural runs on the end of replacement nozzle. The body temperature corresponding to the time of the transient is applied to the structural model from result file from thermal transient analysis of Section A.5.1. The structural runs are documented in computer files *_stRun.out.

Computer output file dCase_stRun.out documents in the first load step the design case run.

Figure A-6: Locations for Thermal Gradients 5

Opening Centerline 4

6 7 1

3 2

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure A-7: FE Model, Crevice Boundary Conditions Opening Centerline Wetted Surface, Vessel Opening Wetted Surface, Inside Nozzle Wetted Surface, Vessel Opening Wetted Surface, Inside Vessel Figure A-8: Structural Run Boundary Conditions Cap Force Opening Centerline Wetted Surface The computer output files *_stPost.out contains two formatted tables for each stress classification path line (shown on Figure A-9). Each *_stPost.out output file reports results for individual transients where the Page 46

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary summary table lists the transient time points, metal temperature at the location of original weld, along with membrane and bending hoop and axial component stresses at the stress classification line away from the opening discontinuity. Refer to the header of each table for the origin of stresses. Refer to Table A-6 for the description of listing as it appears in the applicable output file *_stPost.out.

Table A-6: Column Description

1. Item 1 table line number 2 time in the transient 3 temperature at location of original J-groove weld 4 axial membrane stress 5 axial bending stress, shell inner surface, bending I 6 axial bending stress, shell outer surface, bending O 7 hoop membrane stress 8 hoop bending stress, shell inner surface, bending I 9 hoop bending stress, shell outer surface, bending O Stress components are listed in the cylindrical coordinate system with the RV shell centerline perpendicular to the display plane, hoop direction is the circumferential direction of entire RV shell, and radial direction is radial direction of entire RV shell. Also refer to Figure A-9 for approximate location of the stress classification lines NearPath and FarPath..

Figure A-9: Results, Reported Locations Hoop Direction = Out of Plane Opening Centerline Outside Node Outside Node

[ ]

Path Line: Path Line:

NearPath FarPath

[ ]

Axial Direction Inside Node Inside Node Location of Reported (beneath cladding) (beneath cladding)

Temperature TWELD Page 47

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary A.6 Computer Files The computer files pertinent to revision 000 of this document Appendix A are located in ColdStor directory:

/32-9321034-000/official/AppendixA.

ANSYS Release 19.2 Mechanical Enterprise (latest EASI list version), Reference [16] was used for all FE runs documented herein. Use of this version of ANSYS is acceptable since error notices were reviewed and none was found applicable to this analysis.

Results of the calculations confirm that the inputs and structural responses of the models developed are within the range of applicability of ANSYS Mechanical Enterprise for these types of physical problems.

Computer runs were performed under controlled access of ANSYS Mechanical Enterprise, 19.2 on the approved platform Lynchburg HPCv2. The computer used for this analysis is a multi-node server (auslynchpcc03), the computing nodes used to run this analysis were selected automatically by queuing handling software to be auslynchpc60 and auslynchpc59. Queue number to run this job were 8327264 and 8329983 respectively. Jobs were submitted in interactive mode by Martin Kolar (preparer of revision 000).

The hardware platform for both nodes auslynchpc59 and auslynchpc60: [

] operating system: Red Hat Enterprise Server release [

]

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table A-7: List of Computer Files for Revision 000 crc size (Byte) modified date time file name

./official/AppendixA/01WbModel:

07301 1186198 Nov 4 2020 18:36:33 PeachBottomN16.mesh.dat 53828 409125 Nov 4 2020 18:36:14 PeachBottomN16v0.wbpz

./official/AppendixA/02FeModel:

38752 1489 Nov 3 2020 12:38:13 StructuralModel.mac 11455 2123 Nov 4 2020 21:08:06 ThermalModel.mac

./official/AppendixA/03TransientDefinitions:

63588 1640 Nov 4 2020 15:18:54 HeatCool.mac 39021 1639 Nov 14 2020 9:34:54 LossPmpN.mac 30895 2677 Nov 4 2020 15:18:54 LossPump.mac 10336 1541 Nov 4 2020 15:18:54 OverPres.mac 29088 1032 Nov 4 2020 15:18:54 SingRelf.mac

./official/AppendixA/04TransientRuns:

25710 40848 Nov 5 2020 22:47:03 DesignCase_stPost.out 56060 29630 Nov 5 2020 22:47:02 DesignCase_stRun.out 34926 95133 Nov 5 2020 22:48:02 HeatCool_dT.out 44118 183845 Nov 5 2020 22:48:12 HeatCool_stPost.out 52258 96772 Nov 5 2020 22:48:09 HeatCool_stRun.out 27239 322673 Nov 5 2020 22:48:00 HeatCool_thRun.out 12890 91366 Nov 5 2020 22:48:02 HeatCool_tr.parm 26985 73475 Nov 14 2020 10:09:38 LossPmpN_dT.out 44478 262495 Nov 14 2020 10:09:51 LossPmpN_stPost.out 54019 128585 Nov 14 2020 10:09:48 LossPmpN_stRun.out 41968 229478 Nov 14 2020 10:09:35 LossPmpN_thRun.out 13260 60909 Nov 14 2020 10:09:37 LossPmpN_tr.parm 56190 97047 Nov 5 2020 22:49:12 LossPump_dT.out 52902 355445 Nov 5 2020 22:49:31 LossPump_stPost.out 42378 167204 Nov 5 2020 22:49:27 LossPump_stRun.out 35666 364976 Nov 5 2020 22:49:09 LossPump_thRun.out 14645 95070 Nov 5 2020 22:49:12 LossPump_tr.parm 37167 22412 Nov 5 2020 22:49:46 OverPres_tr.parm 21341 45881 Nov 5 2020 22:49:47 OverPressure_dT.out 15381 205299 Nov 5 2020 22:49:58 OverPressure_stPost.out 26032 105624 Nov 5 2020 22:49:55 OverPressure_stRun.out 41107 111868 Nov 5 2020 22:49:44 OverPressure_thRun.out 14921 25839 Nov 5 2020 22:50:15 SingRelf_tr.parm 63243 48713 Nov 5 2020 22:50:16 SingleRelief_dT.out 18397 148099 Nov 5 2020 22:50:25 SingleRelief_stPost.out 42941 81505 Nov 5 2020 22:50:22 SingleRelief_stRun.out 20006 112139 Nov 5 2020 22:50:13 SingleRelief_thRun.out 63117 2925 Nov 5 2020 14:48:30 StressRun.mac 12137 1156 Nov 5 2020 21:01:35 ThermalRun.mac 26263 1091 Nov 5 2020 22:30:12 dCase_stRun.mac

./official/AppendixA/09ToolBoxFiles:

08803 2393 Nov 13 2020 20:32:32 FractureData.mac 61043 7974 May 11 2017 19:36:45 MaterialProperties.mac 43018 7346 Nov 5 2020 22:46:04 dTpostProcessing.mac Page 49

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary APPENDIX B: SIF SOLUTION TEST CASES The implementation of the SIF solution described in Section 2.1, from Reference [5], was tested to verify the implementation in the spreadsheet by reproducing Figures 10 (for tension) and 11 (for bending) of Reference [5].

The tension test case is shown in Figure B-1 and the bending test case is shown in Figure B-2. Open circles represent digitized data points from Reference [5] figures and solid lines are values calculated by the spreadsheet used in this report. The results show good agreement. The test cases are archived in the excel spreadsheet PeachBottom2_N16A_LEFM_EPFM_v1.xlsm and are stored in the ColdStor as described in Section 5.2.

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure B-1: Test Case for Tension (Based on Figure 10 of [5])

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Figure B-2: Test Case for Bending (Based on Figure 11 of [5])

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary APPENDIX C: FM EVALUATION RESULT TABLES Page 53

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table C-1: LEFM Results - HUCD Transient K Plastic Zone Plastic Zone Corrected K note (1) Membrane Stresses Bending Stresses Total Applied Stress = 0o = 90o = 0o = 90o = 0o = 90o Time Pressure Fluid Temperature Metal Temperature E E' y Pressure (pRi/t) Crack Face Pressure FE Model Bending WRS Crack Face Pressure St Sb KI KI ry ry KIeff KIeff KIC KIC/K KIC/K Transient Service Level Req'd Margin LEFM Check? LEFM/EPFM Applicable?

hr psig °F °F ksi ksi ksi ksi ksi ksi ksi ksi ksi ksi ksiin ksiin in in ksiin ksiin ksiin = 0o = 90o HUCD Normal/Upset OK LEFM Temperature Range HUCD Normal/Upset OK LEFM Temperature Range HUCD Normal/Upset OK LEFM Temperature Range HUCD Normal/Upset OK EPFM Temperature Range HUCD Normal/Upset No Good EPFM Temperature Range HUCD Normal/Upset No Good EPFM Temperature Range HUCD Normal/Upset No Good EPFM Temperature Range HUCD Normal/Upset No Good EPFM Temperature Range HUCD Normal/Upset No Good EPFM Temperature Range HUCD Normal/Upset No Good EPFM Temperature Range HUCD Normal/Upset No Good EPFM Temperature Range HUCD Normal/Upset OK EPFM Temperature Range HUCD Normal/Upset OK EPFM Temperature Range HUCD Normal/Upset OK EPFM Temperature Range HUCD Normal/Upset OK EPFM Temperature Range HUCD Normal/Upset OK EPFM Temperature Range HUCD Normal/Upset OK EPFM Temperature Range HUCD Normal/Upset OK EPFM Temperature Range HUCD Normal/Upset OK EPFM Temperature Range HUCD Normal/Upset OK Transition Temperature Range HUCD Normal/Upset OK LEFM Temperature Range HUCD Normal/Upset OK LEFM Temperature Range HUCD Normal/Upset OK LEFM Temperature Range (1): Material properties at metal temperature.

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table C-2: LEFM Results - Loss of [ ] Pump Transient K Plastic Zone Plastic Zone Corrected K note (1) Membrane Stresses Bending Stresses Total Applied Stress = 0o = 90o = 0o = 90o = 0o = 90o Time Pressure Fluid Temperature Metal Temperature E E' y Pressure (pRi/t) Crack Face Pressure FE Model Bending WRS Crack Face Pressure St Sb KI KI ry ry KIeff KIeff KIC KIC/K KIC/K Transient Service Level Req'd Margin LEFM Check? LEFM/EPFM Applicable?

hr psig °F °F ksi ksi ksi ksi ksi ksi ksi ksi ksi ksi ksiin ksiin in in ksiin ksiin ksiin = 0o = 90o Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range Loss of Pump Normal/Upset No Good EPFM Temperature Range (1): Material properties at metal temperature.

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table C-3: LEFM Results - [ ] Overpressure [ ] Transient K Plastic Zone Plastic Zone Corrected K note (1) Membrane Stresses Bending Stresses Total Applied Stress = 0o = 90o = 0o = 90o = 0o = 90o Time Pressure Fluid Temperature Metal Temperature E E' y Pressure (pRi/t) Crack Face Pressure FE Model Bending WRS Crack Face Pressure St Sb KI KI ry ry KIeff KIeff KIC KIC/K KIC/K Transient Service Level Req'd Margin LEFM Check? LEFM/EPFM Applicable?

hr psig °F °F ksi ksi ksi ksi ksi ksi ksi ksi ksi ksi ksiin ksiin in in ksiin ksiin ksiin = 0o = 90o Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range Over Pressure Emergency/Faulted OK EPFM Temperature Range (1): Material properties at metal temperature.

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table C-4: LEFM Results - Single Relief [ ] Transient K Plastic Zone Plastic Zone Corrected K note (1) Membrane Stresses Bending Stresses Total Applied Stress = 0o = 90o = 0o = 90o = 0o = 90o Time Pressure Fluid Temperature Metal Temperature E E' y Pressure (pRi/t) Crack Face Pressure FE Model Bending WRS Crack Face Pressure St Sb KI KI ry ry KIeff KIeff KIC KIC/K KIC/K Transient Service Level Req'd Margin LEFM Check? LEFM/EPFM Applicable?

hr psig °F °F ksi ksi ksi ksi ksi ksi ksi ksi ksi ksi ksiin ksiin in in ksiin ksiin ksiin = 0o = 90o Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset No Good EPFM Temperature Range Single Relief Normal/Upset OK EPFM Temperature Range Single Relief Normal/Upset OK Transition Temperature Range Single Relief Normal/Upset OK LEFM Temperature Range Single Relief Normal/Upset OK LEFM Temperature Range (1): Material properties at metal temperature.

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Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table C-5: EPFM Results (Section 3.1 of CC N-749) - HUCD Transient Plastic Zone Plastic Zone Corrected K

= 0o = 0o = 90o = 90o = 0o = 90o = 0o = 0o = 90o = 90o = 0o = 90o CVN =[ ]

Time St Sb-SbWRS KIp KIs KIp KIs ry ry KIp KIs KIp KIs Japp Japp J0.1 Transient Service Level Japp/J0.1 EPFM Check?

hr ksi ksi ksiin ksiin ksiin ksiin in in ksiin ksiin ksiin ksiin kips/in kips/in kips/in HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK HUCD Normal/Upset < 1, OK

• Temperatures at these time points are below T c1 , results are for information only.

Page 58

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table C-6: EPFM Results (Section 3.1 of CC N-749) - Loss of [ ] Pump Transient Plastic Zone Plastic Zone Corrected K

= 0o = 0o = 90o = 90o = 0o = 90o = 0o = 0o = 90o = 90o = 0o = 90o CVN =[ ]

Time St Sb-SbWRS KIp KIs KIp KIs ry ry KIp KIs KIp KIs Japp Japp J0.1 Transient Service Level Japp/J0.1 EPFM Check?

hr ksi ksi ksiin ksiin ksiin ksiin in in ksiin ksiin ksiin ksiin kips/in kips/in kips/in Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Loss of Pump Normal/Upset < 1, OK Page 59

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table C-7: EPFM Results (Section 3.1 of CC N-749) - [ ] Overpressure [ ] Transient Plastic Zone Plastic Zone Corrected K

= 0o = 90o = 90o = 0o = 90o CVN =[ ]

o o o o o o o

=0 =0 = 90 = 90 =0 = 90 =0 Time St Sb-SbWRS KIp KIs KIp KIs ry ry KIp KIs KIp KIs Japp Japp J0.1 Transient Service Level Japp/J0.1 EPFM Check?

hr ksi ksi ksiin ksiin ksiin ksiin in in ksiin ksiin ksiin ksiin kips/in kips/in kips/in Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Over Pressure Emergency/Faulted < 1, OK Page 60

Document No. 32-9321037-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair J-Groove One-Cycle Justification Non-Proprietary Table C-8: EPFM Results (Section 3.1 of CC N-749) - Single Relief [ ] Transient Plastic Zone Plastic Zone Correction K CVN =[ ]

o o o o o o

=0 =0 = 90 = 90 o

=0 = 90 =0 = 0o = 90o = 90o = 0o = 90o Time St Sb-SbWRS KIp KIs KIp KIs ry ry KIp KIs KIp KIs Japp Japp J0.1 Transient Service Level Japp/J0.1 EPFM Check?

hr ksi ksi ksiin ksiin ksiin ksiin in in ksiin ksiin ksiin ksiin kips/in kips/in kips/in Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK Single Relief Normal/Upset < 1, OK

• Temperatures at these time points are below T c1 , results are for information only.

Page 61

Attachment 6 Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary, Document Number 32- 9321035-001 (Non-Proprietary Version)

0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY CALCULATION

SUMMARY

SHEET (CSS)

Document No. 32 - 9321035 - 001 Safety Related: Yes No Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Title Proprietary PURPOSE AND

SUMMARY

OF RESULTS:

PURPOSE:

The purpose of this calculation is to justify the operation of Peach Bottom Unit 2 with a repaired Instrumentation Nozzle (N16A) for one operating cycle.

Rev. 001: The proprietary version is updated; accordingly the non-proprietary version is updated.

RESULTS:

The Instrumentation Nozzle repair satisfies the applicable ASME Code requirements for one operating cycle.

Rev. 001: No changes to the calculation.

This is the non-proprietary version of Framatome Document 32-9321033-003.

FRAMATOME INC. PROPRIETARY This document and any information contained herein is the property of Framatome Inc. (Framatome) and is to be considered proprietary and may not be reproduced or copied in whole or in part. This document shall not be furnished to others without the express written consent of Framatome and is not to be used in any way which is or may be detrimental to Framatome. This document and any copies that may have been made must be returned to Framatome upon request.

If the computer software used herein is not the latest version per the EASI list, THE DOCUMENT CONTAINS AP 0402-01 requires that justification be provided.

ASSUMPTIONS THAT SHALL BE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: VERIFIED PRIOR TO USE CODE/VERSION/REV CODE/VERSION/REV Yes None No Page 1 of 18

0402-01-F01 (Rev. 021, 03/12/2018)

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary Review Method: Design Review (Detailed Check)

Alternate Calculation Does this document establish design or technical requirements? YES NO Does this document contain Customer Required Format? YES NO Signature Block P/R/A/M Name and Title and Pages/Sections (printed or typed) Signature LP/LR Date Prepared/Reviewed/Approved Kaihong Wang, K WANG P All.

Advisory Engineer 11/19/2020 Tomas Straka, T STRAKA R All.

Advisory Engineer 11/19/2020 D KIM David Cofflin, for DR COFFLIN A All.

Supervisory Engineer 11/19/2020 Notes: P/R/A designates Preparer (P), Reviewer (R), Approver (A);

LP/LR designates Lead Preparer (LP), Lead Reviewer (LR);

M designates Mentor (M)

In preparing, reviewing and approving revisions, the lead preparer/reviewer/approver shall use All or All except

___ in the pages/sections reviewed/approved. All or All except ___ means that the changes and the effect of the changes on the entire document have been prepared/reviewed/approved. It does not mean that the lead preparer/reviewer/approver has prepared/reviewed/approved all the pages of the document.

With Approver permission, calculations may be revised without using the latest CSS form. This deviation is permitted when expediency and/or cost are a factor. Approver shall add a comment in the right-most column that acknowledges and justifies this deviation.

Project Manager Approval of Customer References and/or Customer Formatting (N/A if not applicable)

Name Title (printed or typed) (printed or typed) Signature Date Comments N/A N/A N/A N/A N/A Page 2

0402-01-F01 (Rev. 021, 03/12/2018)

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary Record of Revision Revision Pages/Sections/Paragraphs No. Changed Brief Description / Change Authorization 000 All Original release 001 Pages 1-6 Revised for Rev. 001.

Pages 7-18 Updated to be consistent with the proprietary version.

Page 3

0402-01-F01 (Rev. 021, 03/12/2018)

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary Engineering Certification The seal of the Professional Engineer applied to this page signifies that this calculation has been prepared under the responsible charge of the Professional Engineer. This document was created to satisfy the structural analysis portion of Section 5.4 of Reference [1], requiring demonstration that requirements of Reference [2] are satisfied. This document does not constitute a Certified Design Report for the full lifetime of the repair.

I, hereby, certify to the best of my knowledge and belief that the analysis herein is correct and complete with respect to its stated purpose.

Printed Name: Don Kim

Title:

Advisory Engineer Signature: Date: 11/19/2020 State: VA License No.: 0402041365 Expiration Date: 7/31/2022 Seal:

Page 4

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary Table of Contents Page SIGNATURE BLOCK ............................................................................................................................. 2 RECORD OF REVISION ....................................................................................................................... 3 ENGINEERING CERTIFICATION.......................................................................................................... 4 LIST OF TABLES .................................................................................................................................. 6

1.0 INTRODUCTION

........................................................................................................................ 7 2.0 PURPOSE AND SCOPE ............................................................................................................ 7 3.0 ANALYTICAL METHODOLOGY................................................................................................. 7 4.0 ASSUMPTIONS ......................................................................................................................... 7 4.1 Unverified Assumptions..................................................................................................................... 7 4.2 Justified Assumptions ........................................................................................................................ 8 5.0 CALCULATIONS ........................................................................................................................ 8 5.1 Primary Stress Evaluation ................................................................................................................. 8 5.1.1 Loading ............................................................................................................................... 8 5.1.2 Primary Stress Calculation ................................................................................................. 9 5.2 Interference Check .......................................................................................................................... 16 5.3 Secondary and Peak Stresses ........................................................................................................ 16 5.4 Corrosion Evaluation ....................................................................................................................... 17 6.0 COMPUTER USAGE ............................................................................................................... 17

7.0 CONCLUSION

......................................................................................................................... 18

8.0 REFERENCES

......................................................................................................................... 18 Page 5

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary List of Tables Page Table 5-1: Local Piping Loads at Pipe-to-Coupling Weld ....................................................................... 9 Table 5-2: Local Piping Loads Under Service Levels at Pipe-to-Coupling Weld ..................................... 9 Table 5-3: J-groove Weld Cross-Sectional Property ............................................................................ 11 Table 5-4: Stress Intensity on J-groove Weld with Level D Loads (Pressure and Piping Loads) .......... 11 Table 5-5: Stress Intensity on J-groove Weld due to Pressure Only..................................................... 12 Table 5-6: Stress Intensity on Replacement Nozzle with Level D Loads (Pressure and Piping Loads) ................................................................................................................................ 13 Table 5-7: Stress Intensity on Replacement Nozzle due to Pressure Only ........................................... 14 Page 6

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary

1.0 INTRODUCTION

The Instrumentation Nozzle (N16A) was found to be leaking at the Peach Bottom Unit 2. A half-nozzle repair is being performed per Reference [1].

Nozzle N16A is located in shell [ ] plant elevation or [ ] above the inside surface of the bottom of the reactor vessel (RV) (Reference [1]). The original nozzle is connected to the vessel wall with a partial penetration J-groove weld made on the inside of the reactor vessel (RV). The repair utilized the half-nozzle approach to modify the original nozzle. The half-nozzle approach replaces the outer portion of the existing nozzle with a new Alloy 690 nozzle and establishes a new pressure boundary on the outside surface of the RV shell with a partial penetration J-groove weld in a new Alloy 52M weld pad. The remnant of the original nozzle remains in place, along with the original J-groove weld. The original [ ] nozzle and the stainless steel safe end are replaced with an Alloy 690 nozzle connected to a stainless steel reducing coupling.

2.0 PURPOSE AND SCOPE This calculation justifies plant operation for one cycle with the repaired nozzle, based on the requirements of the ASME Code (Reference [2]). A subsequent analysis will demonstrate acceptability of the repaired nozzle for operation beyond one cycle.

Per Reference [1], the scope of this analysis includes the modification (new weld pad, new J-groove weld, replacement nozzle) up to the terminal end of the replacement nozzle. The reducing coupling as well as the fillet weld between the coupling and the nozzle end is outside the scope of this analysis.

Rev. 001: The J-groove weld bore size is increased on-site to remove some PT indications (Reference [13]). As a result, both ID and OD of the nozzle near the J-groove weld are increased. The calculation is updated to address the repair deviation from the design, and the as-measured dimensions are used where applicable.

3.0 ANALYTICAL METHODOLOGY The following steps will be performed to demonstrate the acceptability of the half-nozzle repair:

• Acceptability of the new J-groove weld configuration with respect to ASME Code dimensional requirements will be determined.

• Primary stress criteria will be evaluated.

• An assessment of the secondary and peak stresses, and fatigue will be made, with regard to a single cycle of operation.

Methodology for the calculation of required area of reinforcement is provided in Section 5.1.2.4.

4.0 ASSUMPTIONS 4.1 Unverified Assumptions There is no unverified assumption used in this calculation.

Page 7

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary 4.2 Justified Assumptions

1) [

]

2) [

]

5.0 CALCULATIONS 5.1 Primary Stress Evaluation The purpose of this section is to verify the primary stress requirements are met for the design shown in Reference

[3]. The replacement nozzle is shown in Reference [4]. The verification is based on the requirements of Reference

[2] and as specified in Reference [1]. More specifically the following are evaluated in the one cycle justification:

1) Partial penetration J-groove weld (Alloy 52M)

2) New nozzle (Alloy 690)

3) New weld pad (Alloy 52M)

4) Stresses in the vicinity of the opening (Low alloy steel, done by reinforcement check) 5.1.1 Loading The external mechanical loadings are specified in Reference [5]. The maximum internal pressure of [ ] psi occurs during the Hydrostatic Test as specified in Reference [6]. Based on Reference [5], the external loads are applied at the weld between the 1-1/2 pipe and the 2x1-1/2 reducing coupling. It is located [

] from the outside surface of the RV base metal, where [ ] is the distance from the RV outside surface to the nozzle end weld as shown in Reference [3] and [ ] is the height of the coupling (Reference [7]). Applicable loads from Reference [5] are collected in Table 5-1 where the direction A is the nozzle axial positive outwards, B is vertical positive up and C is determined by the right hand rule.

Page 8

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary Table 5-1: Local Piping Loads at Pipe-to-Coupling Weld Load Case FA, lbs FB, lbs FC, lbs MA, ft-lbs MB, ft-lbs MC, ft-lbs WT01 THRM01 SAMOU SAMSS SEISOB SEISDB The load combinations are specified in Reference [5]. No Level C (Emergency) conditions are specified for the instrumentation nozzle in Reference [5]. For the purpose of primary stress evaluation, the load combinations are listed as follows:

Level A and B: [

]

Level D: [ ]

Piping loads at the pipe-to-coupling weld for different service levels are calculated conservatively as the summation of absolute values, as collected in Table 5-2 where directions x, y and z are the directions A, B and C in Table 5-1, respectively.

Table 5-2: Local Piping Loads Under Service Levels at Pipe-to-Coupling Weld Service Load Fx, lbs Fy, lbs Fz, lbs Mx, in-lbs My, in-lbs Mz, in-lbs Level A&B Level D 5.1.2 Primary Stress Calculation Loads listed in Table 5-2 are used to calculate stresses at locations of interest using the following equations:

2 ( + )

Axial stress: = 2 2 + + (1)

PR2 R2 Hoop stress: y = R2 i 2 (Ro2 + 1) (2) o PR2 R2 Radial stress: z = R2 Ri 2 (Ro2 1) (3) o i Mx R F Shear stresses: xy = + As , yz = xz = 0 (4)

J

where, P = maximum pressure, [ ]

Ri = Cross section inner radius, in.

Ro = Cross section outer radius, in.

Page 9

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary Mb = bending moment, in-lbs, =2 + 2 Mx = torsional moment, in-lbs Fx = axial load, lbs Fs = shear load, lbs, =2 + 2 L = moment arm distance, in.

R = distance from centroid to section at which stresses are computed, in.

I =4 (4 4 ), area moment of inertia, in4.

J = 2I, polar moment of inertia, in4.

A = (2 2 ), cross sectional area, in2.

Solving the following equation for the three principal stresses 1 , 2, 3 :

3 x + y + z 2 + x y + y z + x z 2xy 2yz 2xz x y z 2xy yz xz + x 2yz + y 2xz + z 2xy = 0 (5)

Stress intensity (SI) is then: SI = max(l1 2 l, l2 3 l, l1 3 l).

For the primary stress calculation, the level D loads are used conservatively to calculate stresses that are compared to the allowable stress values for level A (i.e., Sm for Pm, 1.5Sm for PL+Pb). The allowable stress intensity Sm for Alloy 52M and Alloy 690 at 575°F is 23.3 ksi, Reference [8]. The primary stresses are calculated at the inner radius, mean radius and outer radius. The mean radius location is used to check the primary membrane limit. The maximum stress from the outer and inner radii is used to check the primary membrane plus bending limit. The mean radius is calculated using the following equation (Ro+Ri)/2.

In the following calculation, moment arm L = [ ] (as aforementioned which included the weld pad thickness) is conservatively used in calculating stresses on the new J-groove weld; moment arm L = [ ]

(distance between the nozzle end and the pipe-to-coupling weld) is used in calculating stresses on the nozzle end considering the distance between the nozzle end and the original pipe-to-coupling weld. The J-groove weld is finally machined to have an oversized bore as shown in Step 5.4 of Reference [3] to remove some PT indications.

The as-measured bore size is [ ] (two measurements taken) per Reference [13]. Accordingly, the replacement nozzle is machined by the final contingency machining shown in Reference [4]. The as-measured nozzle OD for the J-groove is [ ] (Reference [13]).

5.1.2.1 New J-Groove Weld Weld Size (NB-3352.4, Reference [2])

This weld needs to satisfy the minimum dimension requirements of FIG. NB-4244(d)-1(e) and NB-3352.4(d)(2).

With the nozzle wall thickness tn = [ ] (References [13] and [4],

considering also the nozzle ID tolerance):

The minimum value: tc = min(0.7tn, 0.25) = min(0.7* [ ] 0.25) = 0.25. The actual value of tc is conservatively estimated to be: [ ] > 0.25. This requirement is satisfied.

Page 10

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary The fillet leg and the J-groove depth shall be no less than 3/4 tn = 0.75* [ ] The actual J-groove depth value is [ ] and the fillet leg is [ ] This requirement is satisfied.

The weld length along the nozzle OD shall be no less than 1.5tn = 1.5* [ ] The actual value is

[ ] minimum. This requirement is satisfied.

The gap between the nozzle end and the counter bore surface shall be in the range of [ ] and tn

[ ] The actual value is between [ ] This requirement is satisfied.

Nozzle Diametric Clearance (NB-3337.3(a), Reference [2])

For a nozzle OD between 1 and 4 the maximum diametric clearance of 0.020 per NB-3337.3(a) is satisfied with the as-measured dimensions (Reference [13]): [ ] (nozzle OD), [ ] (bore ID max.), diametric clearance = [ ]

Stress Intensity (SI)

Stress intensities on the J-groove weld due to combined loads (pressure, piping loads) are calculated based on the weld throat section, with the Ri and Ro determined as follows.

Ri = (Nozzle OD)/2 Ro = [Nozzle OD +2*(fillet leg)]/2 With the replacement nozzle OD ( [ ] as-measured, Reference [13]) and the fillet leg of [ ]

(Reference [4]), the corresponding cross-sectional properties of the J-groove weld are summarized in Table 5-3.

Table 5-3: J-groove Weld Cross-Sectional Property Nozzle OD Ri, in. Ro, in. I, in4 J, in4 A, in2

[ ] [ ] [ ] [ ] [ ] [ ]

With the Level D piping loads (Table 5-2) applied to Equations (1) to (5), considering also the pressure load, the SIs on the J-groove weld are calculated, as listed in Table 5-4.

Table 5-4: Stress Intensity on J-groove Weld with Level D Loads (Pressure and Piping Loads)

Component stress, psi Principal stress, psi SI Nozzle OD Location x y z xy 1 2 3 psi Inside

[ ] Outside Mean Page 11

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary By Table 5-4, with Level D loads and Level A criteria, the highest primary membrane stress intensity is

[ ] ksi < Sm (=23.3 ksi), and the highest membrane plus bending stress intensity is [ ] ksi

< 1.5Sm (=34.95 ksi). The primary stress requirements for the J-groove weld are satisfied.

For comparison purpose, stress intensities on the J-groove due to the maximum pressure only ( [ ] psig Hydrostatic Test pressure) are listed in Table 5-5.

Table 5-5: Stress Intensity on J-groove Weld due to Pressure Only Component stress, psi Principal stress, psi SI Nozzle OD Location x y z xy 1 2 3 psi Inside

[ ] Outside Mean Pure Shear (NB-3227.2)

By Table 5-4, the maximum primary shear stress calculated from the transverse shear forces and the torsional moment across the J-groove weld throat cross-section is [ ] psi, which is less than 0.6Sm (=0.6*23.3=13.98 ksi) the allowable for the average primary shear stress.

In addition, axial forces on the nozzle (and torsional moment as well) may develop shear stresses along the weld interface with the nozzle outside surface. The shear area As = [ ] in2, where [ ] is the as-measured nozzle OD and [ ] is the J-groove depth; weld fillet leg is conservatively not considered.

The axial force due to pressure and piping loads is Fv = [ ] lbs, where

[ ] psig is the pressure, [ ] is the as-measured J-groove bore ID (max. value) and [ ] lbs is the piping axial load. The shear stress due to axial forces is then Fv/As = [ ] psi.

Conservatively adding the shear stress above ( [ ] psi), the total is [ ] psi ( [ ] ),

which is less than 0.6Sm (=0.6*23.3=13.98 ksi) the allowable for the average primary shear stress.

This requirement is satisfied.

5.1.2.2 New Nozzle Tentative Pressure Thickness (NB-3324.1)

For the thick portion of the nozzle,

=

+0.5 where Ro is the outside radius of the nozzle, P the Design Pressure ( [ ] psi, Reference

[9] )

The as-measured nozzle OD is [ ] (Reference [13]). With P ( [ ] psi), Ro ( [

] ) and Sm (23.3 ksi), the tentative pressure thickness is

[ ] x [ ]

= =[ ] .

23300 + 0.5 x [ ]

Page 12

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary The minimum possible nozzle wall thickness considering the nozzle ID tolerances is

[ ]

For the thin portion of the nozzle,

=

where R = [ ] is the inside radius of the nozzle end, P the Design 0.5 Pressure ( [ ] psi)

[ ] x [ ]

] [ ] .

23300 0.5 x [

The nozzle wall thickness of all three sizes at the nozzle thin end is

[ ]

Therefore, the tentative thickness requirement is met.

Stress Intensity (SI)

Stress intensities on the replacement nozzle due to combined loads (pressure, piping loads) are calculated based on the cross-section at the terminal end of the nozzle, with the Ri and Ro as follows. Primary stresses calculated at this location of the nozzle bounds those in other part of the nozzle.

Ri = [ ]

Ro = [ ]

With the Level D piping loads (Table 5-2) applied to Equations (1) to (5), the SIs on the replacement nozzle are calculated, as listed in Table 5-6.

Table 5-6: Stress Intensity on Replacement Nozzle with Level D Loads (Pressure and Piping Loads)

Component stress, psi Principal stress, psi SI Location x y z xy 1 2 3 psi Inside Outside Mean By Table 5-6, with Level D loads that are significantly higher than the Level A/B loads, and with Level A criteria, the highest primary membrane stress intensity is [ ] ksi < Sm (=23.3 ksi), and the highest membrane plus bending stress intensity is [ ] ksi < 1.5Sm (=34.95 ksi). The primary stress requirements for the replacement nozzle are satisfied.

For comparison purpose, stress intensities on the nozzle due to the maximum pressure only ( [ ] psig Hydrostatic Test pressure) are listed in Table 5-7.

Page 13

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary Table 5-7: Stress Intensity on Replacement Nozzle due to Pressure Only Component stress, psi Principal stress, psi SI Location x y z xy 1 2 3 psi Inside Outside Mean 5.1.2.3 Weld Pad The cross-section of the weld pad is significantly larger than the J-groove weld cross-section and it is made of an equivalent material. [ ]

The primary stress requirements for the weld pad are satisfied, as the requirements are satisfied for the J-groove weld.

5.1.2.4 Reinforcement Requirements for Openings NB-3332.1, Reference [2] is used to determine the reinforcement requirements for the 2 N16A nozzle.

5.1.2.4.1 Methodology The required parameters used to demonstrate that the N16A nozzle opening does not require reinforcement are determined using NB-3332.1 (a), NB-3332.1 (b) and NB-3332.1 (c), Reference [2] as follows:

1) The repaired nozzle bore diameter, including the corrosion over the remaining service life is compared with the maximum allowable opening diameter determined per NB-3332.1 (a). In addition, the sum of diameters of unreinforced openings within a specified circle is compared with the required parameter per NB-3332.1 (a).

2) The distance between unreinforced openings is compared with the minimum requirement per NB-3332.1 (b).

3) The distance of unreinforced opening to the edge of a locally stressed area is compared with the minimum requirement per NB-3332.1 (c).

5.1.2.4.2 NB-3332.1 (a)

1) A single opening has a diameter not exceeding 0.2 = [ ]

=[ ]

where: R is the mean radius, = +

2 Ri = [ ] is the inside radius to the base metal taken from Reference [9] Part 1 of 5, page 673.

t= [ ] is the nominal thickness of the vessel shell taken from Reference [9] Part 1 of 5, page 696.

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Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary The as-measured nozzle bore diameter is [ ] (Reference [13], max. value). The corrosion rate of

[ ] inches per year is taken from Reference [10]. Service duration is conservatively considered for

[ ] years.

The maximum bore diameter considering corrosion for [ ] years and bore tolerances is therefore [

] in + ( [ ] in/year x [ ] years).

It is concluded that the final bore diameter of [ ] inches is smaller than the maximum diameter allowed for unreinforced openings of [ ]

2) or if there are two or more openings within any circle of diameter 2.5 = [ ] but the sum of the diameters of such unreinforced openings shall not exceed 0.25 = [ ]

There are no openings within the circle of [ ] inches of diameter assessed based on Reference [9] Part 1 of 5, page 672.

5.1.2.4.3 NB-3332.1 (b)

No two unreinforced openings shall have their centers closer to each other, measured on the inside of the vessel wall, than 1.5 times the sum of their diameters.

The closest unreinforced nozzle per Reference [9], Part 1 of 5, page 672, is another 2 instrumentation nozzle. By inspection these nozzles are farther apart than 1.5 times the sum of their diameters.

5.1.2.4.4 NB-3332.1 (c)

NB-3332.1(c) requires that no unreinforced opening shall have its center closer than 2.5 to the edge of a locally stressed area in the shell. The distance of 2.5 was determined to be [ ] Per Reference [9], the only discontinuities within [ ] of the subject opening that could possibly lead to a locally stressed area in the shell are the Jet Pump Riser Support Pads and the Surveillance Specimen Brackets.

However, neither of these discontinuities creates a locally stressed area in the shell. The closest applicable guidance(1) in Table NB-3217-1 is for Any shell or head, near nozzle or other opening. Based on that guidance, and only considering stresses in the shell (per NB-3332.1(c)), only membrane stress from this discontinuity can possibly be classified as PL. Bending in the shell is clearly Secondary. Regardless of how much load exists on these pads or brackets, the membrane stress induced in the shell cannot be significant. As already stated, bending in the shell would be classified as Secondary (Q), and any stresses from stress concentrations at the pad or bracket juncture with the shell are clearly Peak stress (F). Since the stresses in these regions are either Q or F, they are not PL, and this is not a locally stressed area in the shell. Since there are no locally stressed areas in the shell within

[ ] NB-3332.1(c) is satisfied.

(1)

It is recognized that this is not an opening, and while there is no direct guidance for an attachment, this is consistent with the clear intent of the Code.

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Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary 5.1.2.4.5 Conclusion of Reinforcement Requirement for Openings The above calculation concluded that no reinforcement is required per the 2013 edition of the ASME code, Section NB-3332.1.

5.2 Interference Check There is a minimum 1/16 gap between the end of the original nozzle remnant and the replacement nozzle. A conservative calculation will be done to verify that this gap is sufficient to accommodate thermal growth, L.

Interference between the nozzle and the nozzle remnant Original Nozzle material: [ ]

Nozzle thermal expansion coefficient: noz = 8.2x10-6 in/in/°F (conservatively use Alloy 690 value at 600°F from Reference [8] for [ ])

Nozzle length: L = [ ] (use full thickness of RV base metal and the new wed pad, see Reference [3])

Nozzle temperature: T = [ ] (use highest operating temperature from Reference [6])

L = L* noz* T = [ ]

The nozzle thermal growth of [ ] is less than the minimum gap of [ ] The gap is sufficient to prevent interference.

Interference between the nozzle and the reducing coupling Reducing coupling material: [ ]

Reducing coupling thermal expansion coefficient: ss = [ ] in/in/°F (SS at [ ] °F from Reference [8])

Since the SS coupling has a higher thermal expansion coefficient than that of the Alloy 690 (replacement nozzle), the gap is increased at elevated temperatures and no interference is expected.

5.3 Secondary and Peak Stresses The ASME Code places a limit on secondary stresses in order to prevent failure by excessive distortion caused by the repeated application of loads. The Code also limits peak stresses, through the cumulative fatigue usage factor, in order to prevent failure by fatigue.

The repair weld and replacement nozzle are subject to the same transients as the original design. However, the original weld was on the inside surface of the vessel, while the repair weld is located on the outside surface of the vessel. As compared with the original J-groove weld location, fluid flow rate is significantly lower at the new J-groove weld location, resulting in lower heat transfer at the new J-groove weld. Therefore, the new J-groove weld will experience less severe transient thermal stresses, and the primary plus secondary stress intensity range of the repair weld is no larger than that on the original weld. The P+Q stress range due to piping loads is negligible, as the main contribution to the SI range is due to the pressure load from a comparison of values presented in Table 5-4 and Table 5-5. Secondary stresses due to hole dilation are not significantly different between the original J-groove weld and new J-groove weld. It can be concluded that the single cycle fatigue usage factor for the repair is [ ] of the usage factor as analyzed in Reference [9]. Since the usage factors Page 16

Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary in Reference [9] are all within the limit (1.0), there is ample margin to the ASME fatigue criteria for this one cycle justification.

Per Reference [9], the primary plus secondary (P+Q) stress intensity range calculated for the original nozzle exceeded the allowable (3Sm); it was then justified through the simplified elastic-plastic analysis. The replacement nozzle end where the reducing coupling is welded has the same dimensions as the original nozzle safe end. The original safe end is made of stainless steel ( [ ] ), which has the same thermal expansion coefficient as the stainless coupling ( [ ] ). With the replacement nozzle, the safe end is eliminated and the coupling is directly welded on to the nozzle end. Since the thermal expansion coefficient of the SS coupling is higher than that of the Alloy 690 nozzle, thermal stresses may develop in the nozzle at high temperature when the coupling is fitted in.

The weld connecting the coupling and the nozzle is evaluated in Reference [11] using NB-3600 piping criteria.

The P+Q intensity range due to thermal effects is [ ] ksi (Reference [11]). The stresses in this piping analysis were based on coefficients of thermal expansion (CTEs) taken at room temperature, consistent with piping rules. The difference in CTEs between the nozzle and the coupling at room temperature is

[ ] However, using vessel rules, the CTEs would be taken at operating temperature. This leads to a CTE difference of [ ] Considering the difference in analysis methodology between NB-3 .e., 1.6/0.8) is used as a conservative estimate of the P+Q SI range from differential thermal growth at the nozzle end. This is a conservative estimate because the piping analysis is required to use the elastic moduli (E) at room temperature, where vessel rules would use Es at operating temperature. Therefore, a conservative estimate for the stress caused by differential thermal growth is [ ] ksi.

With the primary stresses due to pressure and piping loads as calculated in Section 5.1.2.2, the total P+Q SI range at the nozzle end may be estimated to be [ ] ksi, which is less than the allowable 3Sm

(=3*23.3 = 69.9 ksi).

Considering a factor of [ ] for fatigue evaluation, the magnitude of alternating stress is: Salt =

[ ] ksi. By the design fatigue curve in Fig. I-9.2 of Reference [12], the allowable number of cycles is over 700. In addition to the start up and shut down transients, SCRAM (Loss of Feedwater Pumps) and the Post Pressure Test Flushing are the only transients out of Normal/Upset transients that may have some contribution to the fatigue usage, per Report #21 in Reference [9]. At Region B, temperature variation of SCRAM is less than that during start up and shut down. Based on the design number of cycles specified in Reference [5],

as the projected number of cycles, it is considered sufficient to consider one start up and shut down cycle plus two other transients for the one cycle operation. To be conservative, [

] This yields the final fatigue usage factor to be

[ ] for the nozzle.

5.4 Corrosion Evaluation Corrosion effects have been evaluated in Reference [10] and are considered in Section 5.1.2.4 for reinforcement requirements. Corrosion has no impact on the replacement nozzle and new pad.

6.0 COMPUTER USAGE No specific engineering software is used in this calculation.

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Document No. 32-9321035-001 PROPRIETARY Peach Bottom 2 N16A Instrument Nozzle Repair Stress One-Cycle Justification Non-Proprietary

7.0 CONCLUSION

The repair of instrumentation nozzle N16A is acceptable for at least one fuel cycle of operation.

8.0 REFERENCES

1. [

]

2. ASME Boiler and Pressure Vessel Code,Section III, Division 1, 2013 Edition.

3. [

]

4. [ ]

5. [ ]

6. [ ]

7. ASME B16.11-2016, Forged Fittings, Socket-Welding and Threaded.

8. ASME Boiler and Pressure Vessel Code,Section II, Part D, 2013 Edition.

9. [ ]

10. [

]

11. [

]

12. ASME Boiler and Pressure Vessel Code,Section III Appendices, 2013 Edition.

13. [

]

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Attachment 7 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification, Document Number 51-9321006-001 (Non-Proprietary Version)

20004-026 (08/12/2020)

Framatome Inc.

Engineering Information Record Document No.: 51 - 9321006 - 001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification Page 1 of 15

20004-026 (08/12/2020)

Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification Safety Related? YES NO Does this document establish design or technical requirements? YES NO Does this document contain assumptions requiring verification? YES NO Does this document contain Customer Required Format? YES NO Signature Block Pages/Sections Name and P/LP, R/LR, M, Prepared/Reviewed/

Title/Discipline Signature A-CRF, A Date Approved or Comments Roluf Andersen RB ANDERSEN P All Engineer I Materials Engineering 11/14/2020 Stacy Yoder Engineer III SL YODER R All Materials Engineering 11/14/2020 Ryan Hosler M All Supervisory Engineer RS HOSLER Materials Engineering 11/14/2020 Ryan Hosler A All RS HOSLER Supervisory Engineer 11/14/2020 Materials Engineering Note: P/LP designates Preparer (P), Lead Preparer (LP)

M designates Mentor (M)

R/LR designates Reviewer (R), Lead Reviewer (LR)

A-CRF designates Project Manager Approver of Customer Required Format (A-CRF)

A designates Approver/RTM - Verification of Reviewer Independence Project Manager Approval of Customer References (N/A if not applicable)

Name Title (printed or typed) (printed or typed) Signature Date Alan Stalker Project Manager AR STALKER 11/14/2020 Project Manager signature above indicates the applicable IBPE approval of Reference [5].

Page 2

20004-026 (08/12/2020)

Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification Record of Revision Revision Pages/Sections/

No. Paragraphs Changed Brief Description / Change Authorization 000 All Original release (November 2020). The Proprietary version of this document is 51-9320932-000.

001 See Description Updated per the proprietary version of this document, 51-9320932-001.

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Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification Table of Contents Page SIGNATURE BLOCK ............................................................................................................................. 2 RECORD OF REVISION ....................................................................................................................... 3 LIST OF FIGURES ................................................................................................................................ 5 1.0 PURPOSE ................................................................................................................................. 6 2.0 ASSUMPTIONS ......................................................................................................................... 9 2.1 Assumptions Requiring Verification ................................................................................ 9 2.2 Justified Assumptions ..................................................................................................... 9 3.0 CORROSION OF EXPOSED LOW ALLOY STEEL.................................................................... 9 3.1 General Corrosion .......................................................................................................... 9 3.2 Galvanic Corrosion ....................................................................................................... 10 3.3 Crevice Corrosion ......................................................................................................... 10 3.4 Stress Corrosion Cracking ............................................................................................ 10 4.0 CORROSION OF ALLOY 690 AND ALLOY 52M ..................................................................... 13

5.0 CONCLUSION

......................................................................................................................... 13

6.0 REFERENCES

......................................................................................................................... 14 Page 4

Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification List of Figures Page Figure 1-1: Original Configuration (Shown with Sealing Plug in Place) [1] [2] ........................................ 7 Figure 1-2: Final Repair Configuration (Shown with Sealing Plug in Place) [1] [2] ................................. 8 Figure 3-1: [

] ......................................................................................................... 12 Page 5

Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification 1.0 PURPOSE The repair of the N16-A reactor vessel nozzle in the Peach Bottom Unit 2 reactor vessel will change the penetration configuration in the following ways: 1) the repair exposes the low alloy steel (LAS) reactor vessel to water conditions, 2) the repair includes a new Alloy 690 nozzle as part of the pressure boundary, and 3) the repair includes a new Alloy 52M weld pad and partial penetration J-groove weld as part of the pressure boundary [1]

[2]. Also, the reducing coupling to nozzle weld is now an Alloy 52M dissimilar metal weld. The original configuration and the final repair configuration, as well as materials, are shown in Figure 1-1 and Figure 1-2 respectively.

The following corrosion evaluation considers potential material degradation due to each of these changes.

Information contained in bold brackets in this document is considered Proprietary to Framatome.

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Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification Figure 1-1: Original Configuration (Shown with Sealing Plug in Place) [1] [2]

Page 7

Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification Figure 1-2: Final Repair Configuration (Shown with Sealing Plug in Place) [1] [2]

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Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification 2.0 ASSUMPTIONS 2.1 Assumptions Requiring Verification

[ ]

2.2 Justified Assumptions 3.0 CORROSION OF EXPOSED LOW ALLOY STEEL The LAS reactor vessel material exposed due to the repair, as shown in red in Figure 1-2, will be in the water space environment given the elevation of the N16-A nozzle [1]. The requirements of the Reactor Water Chemistry control program for Peach Bottom are based on BWRVIP-190, Revision 1 [3] [4].

3.1 General Corrosion Due to the repair configuration, a small portion of the LAS reactor vessel material will be openly exposed to boiling water reactor (BWR) water and, thus, general corrosion is considered. [

]

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Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification 3.2 Galvanic Corrosion 3.3 Crevice Corrosion

[

] The environmental conditions in a crevice can become aggressive with time and can cause accelerated local corrosion.

3.4 Stress Corrosion Cracking Page 10

Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification Although it is very unlikely that SCC cracks will initiate and propagate in LAS under normal BWR conditions, it is impossible to completely rule out. Hence, it is prudent to examine the feasibility of performing an allowable flaw evaluation for an assumed flaw propagating from the J-groove weld into the LAS by applying the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code Section XI criteria [10].

[

]

• As noted in Section 3.0, requirements of the Reactor Water Chemistry control program for Peach Bottom are based on BWRVIP-190, Revision 1. See Section 2.2 for Justified Assumption 1 for additional details regarding [ ]

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Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification Figure 3-1: [

]

This CGR equation/curve was used to support the ASME Section XI analysis [13], which concluded that the postulated flaw is acceptable for one cycle of operation.

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Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification 4.0 CORROSION OF ALLOY 690 AND ALLOY 52M Stress corrosion cracking failures of Alloy 600 and its associated weld metals (Alloy 82/182) have occurred in domestic and international light water reactors. The BWR industry addressed this issue by replacing or modifying affected materials with a modified version of Alloy 600 and Alloy 82/182 [14]. The modified Alloy 82/182 added carbide stabilizers (niobium and tantalum) to minimize chromium depletion at the grain boundaries. The pressurized water reactor (PWR) industry selected Alloy 690 and Alloy 52/152 as replacement materials [15].

Alloy 690 was also thermally treated to improve the microstructure, but grain boundary chromium depletion of Alloy 690/52/152 was avoided by doubling the chromium content (from ~15% to ~30%) instead of using carbide stabilizers. Laboratory studies indicate that Alloy 690 and Alloy 52/152 have superior SCC resistance relative to the non-modified Alloy 600 and Alloy 82/182 [15].

Although most testing of Alloy 690/52/152 has been under PWR conditions, some studies have been performed in environments more similar to BWRs. Creviced U-bend specimens of Alloy 600 and Alloy 690 were tested at 600°F for 48 weeks with an environment of 6 ppm oxygen [16]. The Alloy 600 readily cracked, whereas Alloy 690 showed no cracking. Also, testing of Alloy 690 in high purity water containing 36 ppm oxygen at 289°C

(~550°F) for 47 weeks resulted in no cracking [16].

Extensive testing has been performed on Alloy 52/152 in high temperature deaerated water, which indicate that Alloy 52/152 is much less susceptible to SCC compared to Alloy 82/182 (the Alloy 600 weld metal) [15] [17]

[18]. Test data of Alloy 52/152 in a high temperature oxygenated environment is not readily available, but Alloy 52/152 is expected to have a low susceptibility to SCC under these conditions as well based on the similarity of Alloy 52/152 to Alloy 690.

The only difference between the Alloy 52M to be used in the repair and Alloy 52/152 are small alloying additions to improve weldability. The corrosion resistance is expected to be similar. Based on laboratory studies and operating experience, the replacement higher chromium content nickel-based alloys (Alloy 690 and Alloy 52M) are much less susceptible to SCC than Alloy 600 and Alloy 182 and SCC of these materials is not expected during the life of the modification.

5.0 CONCLUSION

The modification of the N16-A reactor vessel nozzle at Peach Bottom exposes the LAS reactor vessel in a small area to a water environment and introduces new materials (Alloy 690 and Alloy 52M). For the exposed LAS, general corrosion, galvanic corrosion, crevice corrosion, and SCC were evaluated. It is concluded that 1) galvanic corrosion and crevice corrosion are bound by general corrosion, 2) the projected material loss by general corrosion is not a concern for one fuel cycle based on the Section III analysis, and 3) SCC is not a concern for one fuel cycle based on the Section XI analysis. In addition, it is concluded that SCC of the replacement higher chromium content nickel-based alloys (Alloy 690 and Alloy 52M) is not a concern over the life of the modification.

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Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification

6.0 REFERENCES

References identified with an (*) are maintained within Exelon Records System and are not retrievable from Framatome Records Management. These are acceptable references per Framatome Administrative Procedure 0402-01, Attachment 7. See page 2 for Project Manager Approval of customer references.

1. [

]

2. [

]

3. *BWRVIP-190 Revision 1: BWR Vessel and Internals Project, Volume 2: BWR Water Chemistry Guidelines - Technical Basis. EPRI, Palo Alto, CA: 2014. 3002002623.

4. [

]

5. [ ]

6. [

]

7. ASM Handbook, Volume 13, Corrosion, Formerly 9th Edition, Metals Handbook.

8. D.C. Vreeland, et al., Corrosion of Carbon and Low-Alloy Steels in Out-of-Pile Boiling-Water-Reactor Environment, Corrosion, Vol 17, No. 6, 1961.

9. [

]

10. ASME B&PV Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Division 1, 2013 Edition, Subject to the conditions of 10 CFR 50.55a.

11. [

]

12. [

]

13. [

]

14. NUREG/CR-6923, Expert Panel Report on Proactive Materials Degradation Assessment.

15. Materials Reliability Program (MRP): Resistance to Primary Water Stress Corrosion Cracking of Alloys 690, 52, and 152 in Pressurized Water Reactors (MRP-111). EPRI, Palo Alto, CA: 2004. 1009801.

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Document No.: 51-9321006-001 Corrosion Evaluation of the Peach Bottom Unit 2 N16-A Reactor Vessel Nozzle Modification

16. Sedriks, A.J., Schultz, J.W., Cordovi, M.A., Inconel Alloy 690 - A New Corrosion Resistant Material, Corrosion Engineering (Boshoku Gijutsu), vol. 28, pp. 82-95, 1979, Japan Society of Corrosion Engineering.

17. M. J. Psaila-Dombrowski et al., Evaluation of Weld Metals 82, 152, 52 and Alloy 690 Stress Corrosion Cracking and Corrosion Fatigue Susceptibility, Eighth International Symposium on Environmental Degradation of Materials In Nuclear Power Systems - Water Reactors, Aug 10-14 1997, Amelia Island, FL, ANS.

18. Crum, J.R., Nagashima, T., Review of Alloy 690 Steam Generator Studies, Eight International Symposium on Environmental Degradation of Materials In Nuclear Power Systems - Water Reactors, Aug 10-14 1997, Amelia Island, FL, ANS.

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