2CAN122103, Relief Request ANO2-RR-21-002, Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 46 - Submittal of Analyses - Affidavits and Calculation Summary Sheet

Relief Request ANO2-RR-21-002, Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 46 - Submittal of Analyses - Affidavits and Calculation Summary Sheet

ML21344A071
Person / Time
Site:	Arkansas Nuclear
Issue date:	11/19/2021
From:	Opsal P Entergy Operations
To:	Office of Nuclear Reactor Regulation
Shared Package
ML21344A068	List: 2CAN122103, Relief Request ANO2-RR-21-002, Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 46 - Submittal of Analyses - Affidavits and Calculation Summary Sheet ML21344A069
References
2CAN122103 32-9338774-001
Download: ML21344A071 (137)

Text

Attachment 6 to 2CAN122103 Affidavit for Document Number 32-9338774-001

A F F I D A V I T

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 Framatome Calculation Summary Sheet 32-9338774-001

Title:

ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification. Information contained in this Document 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.

This Document contains 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 this Document as proprietary and confidential.

5.

This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document 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 this Document 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 this Document 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, 2021.

Philip A. Opsal Executed ed ed ed ed ed ed ed ed ed ed ed ed ed ed ed ed ed ed ed ed ed on November 19, 2021.

to 2CAN122103 Affidavit for Document Number 32-9338933-001

A F F I D A V I T

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 Framatome Calculation Summary Sheet 32-9338933-001

Title:

OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO-2. Information contained in this Document 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.

This Document contains 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 this Document as proprietary and confidential.

5.

This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document 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 this Document 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 this Document 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, 2021.

Philip A. Opsal Executed e on November 19, 2021.

to 2CAN122103 Affidavit for Document Number 32-9338944-001

A F F I D A V I T

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 Framatome Calculation Summary Sheet 32-9338944-001

Title:

ANO-2 CEDM IDTB Weld Repair One-Cycle Justification. Information contained in this Document 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.

This Document contains 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 this Document as proprietary and confidential.

5.

This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document 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 this Document 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 this Document 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, 2021.

Philip A. Opsal Executed ed ed ed ed ed ed ed ed ed ed ed ed ed ed ed ed ed on November 19, 2021.

to 2CAN122103 Affidavit for Document Number 51-9338718-001

A F F I D A V I T

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 Framatome Engineering Information Record 51-9338718-001

Title:

PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair. Information contained in this Document 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.

This Document contains 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 this Document as proprietary and confidential.

5.

This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document 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 this Document 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 this Document 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, 2021.

Philip A. Opsal Executed on November 19, 2021.

Phili A O l

0 to 2CAN122103 Affidavit for Document Number 51-9338948-001

A F F I D A V I T

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 Framatome Engineering Information Record 51-9338948-001

Title:

Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair Information contained in this Document 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.

This Document contains 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 this Document as proprietary and confidential.

5.

This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document 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 this Document 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 this Document 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, 2021.

Philip A. Opsal Executted ed ed ed ed ed ed ed ed ed ed ed e on November 19, 2021.

1 to 2CAN122103 ANO-2 CEDM Penetration 46 Modification As-Left J-Groove One Cycle Justification Document Number 32-9339466-001 NON-PROPRIETARY

Page 1 of 20 0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY CALCULATION

SUMMARY

SHEET (CSS)

Document No.

32 9339466 001 Safety Related: Yes No Title ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification -

Non Proprietary PURPOSE AND

SUMMARY

OF RESULTS:

PURPOSE: During the Fall 2021 outage (2R28) at Arkansas Nuclear One Unit 2 (ANO-2), an axial indication was discovered on the downhill side of Control Element Drive Mechanism (CEDM) Penetration No. 46 on the reactor vessel closure head (RVCH).

Therefore, a half nozzle repair is being performed, which removes and replaces the lower portion of the CEDM nozzle, using the inside diameter tempered bead (IDTB) weld process to attach the replacement nozzle to the RVCH and the remaining upper portion of the CEDM nozzle. The repair moves the pressure boundary from the existing J-Groove weld (JGW) to the new pressure boundary weld located in the RVCH penetration bore above the original JGW. The purpose of this evaluation is to perform a one cycle justification (OCJ) to assess the suitability of leaving a degraded, as-left J-Groove weld (ALJGW) in the RVCH following the CEDM nozzle repair.

Revision 001: The purpose of revision 001 is to add Appendix B to address contingency repairs identified in Reference 8.

SUMMARY

OF RESULTS: As summarized in Section 5.0, it is demonstrated by comparative analysis that based on evaluation of fatigue crack growth of the as-left J-Groove weld flaw into the low alloy steel RVCH, the ASME Code,Section XI, IWB-3612 requirements for fracture toughness are met for at least one fuel cycle (18 months) based on the transient input provided in Reference

1. In addition, the primary stress limits considering reinforcement requirements of NB-3330 are met, considering a local area reduction of the pressure retaining membrane of the nozzle opening that includes the area of the JGW and a conservatively bounding flaw size for the 18-month fuel cycle.

Based on the comparative analysis between ANO-2 and an existing ALJGW evaluation for a similar unit Plant A, the following conservatisms are noted for the ANO-2 configuration:

x The Plant A evaluation is based on the final flaw size at the predicted end life of the repair, which is [

] The ANO-2 OCJ requires evaluation for only 1.5 years (18 months). Table 4-3 summarizes the transient cycles for each plant for the applicable number of years, which demonstrates the cycles considered for Plant A are conservative.

x The Plant A RVCH radius is about [

] than the ANO-2 RVCH radius, while the RVCH thickness. [

] which results in conservative primary stresses for ANO-2. In addition, the initial flaw depth for Plant A is

[

] than the flaw depth for ANO-2.

x The Plant A evaluation used the lower bound crack arrest fracture toughness, KIa, instead of the crack initiation fracture toughness, KIc. In addition, the Plant A evaluation considers a RTNDT of [

] while a RTNDT of [

] is applicable to ANO-2. Both factors result in a conservative calculation of the structural margins per the ASME code requirement for ANO-2.

x The reinforcement requirements of ASME NB-3330 consider the reduction in the nozzle opening area including the JGW and flaw growth area based on the flaw growth at the end life for Plant A repair, which as summarized above is very conservative for ANO-2.

All other items considered are comparable between ANO-2 and Plant A.

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, AP 0402-01 requires that justification be provided.

THE DOCUMENT CONTAINS ASSUMPTIONS THAT SHALL BE VERIFIED PRIOR TO USE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT:

CODE/VERSION/REV CODE/VERSION/REV Yes No NONE Controlled Document

Document No. 32-9339466-001 0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 2 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 Name and Title (printed or typed)

Signature P/R/A/M and LP/LR Date Pages/Sections Prepared/Reviewed/Approved Jennifer Nelson Principal Engineer LP All Ashok Nana Advisory Engineer M

All Samer Mahmoud Advisory Engineer LR All Ryan Hosler Supervisory Engineer A

All 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 (printed or typed)

Title (printed or typed)

Signature Date Comments Mark Michaels

 



 

 


 

 



 

 





 



 

 



Controlled Document

Document No. 32-9339466-001 0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 3 Record of Revision Revision No.

Pages/Sections/Paragraphs Changed Brief Description / Change Authorization 000 All Original Release. The corresponding proprietary document is 32-9338774-000.

001 All Proprietary information in this document is indicated by bolded brackets ([ ]). The corresponding proprietary document is 32-9338774-001.

Pages 1-6 Updated to include Revision 001 details/changes.

Section 1.0 Added purpose of Revision 001.

Section 6.0 Updated the revision level of Reference 8, which is revised to add contingency repairs.

Added Reference 15.

Appendix B Added Appendix B to address contingency repairs identified in Reference 8.

Controlled Document

Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 4 Table of Contents Page SIGNATURE BLOCK................................................................................................................................ 2 RECORD OF REVISION.......................................................................................................................... 3 LIST OF TABLES..................................................................................................................................... 5 LIST OF FIGURES................................................................................................................................... 6 1.0 PURPOSE..................................................................................................................................... 7 2.0 ANALYTICAL METHODOLOGY................................................................................................... 7 2.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612)..................................................... 7 2.2 Primary Stress Limits (NB-3000)....................................................................................................... 8 3.0 ASSUMPTIONS............................................................................................................................ 8 3.1 Unverified Assumptions..................................................................................................................... 8 3.2 Justified Assumptions........................................................................................................................ 8 4.0 CALCULATION............................................................................................................................. 9 4.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612) Evaluation [

].......... 9 4.1.1 Geometry............................................................................................................................ 9 4.1.2 Material.............................................................................................................................10 4.1.3 Weld Residual Stresses....................................................................................................11 4.1.4 Transient Loading Conditions...........................................................................................12 4.1.5 Review of ASME Section XI Criteria.................................................................................13 4.2 Primary Stress Limit Evaluation (NB-3000).....................................................................................13 5.0

SUMMARY

OF RESULTS..........................................................................................................17

6.0 REFERENCES

............................................................................................................................18 APPENDIX A : EFFECTS OF WRS + [

] ON SIF.......................19 APPENDIX B : JUSTIFICATION FOR CONTINGENCY REPAIRS......................................................20 Controlled Document

Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 5 List of Tables Page Table 4-1: Geometry Comparison..........................................................................................................10 Table 4-2: Material [

].......................................................................................................11 Table 4-3: Transient Cycles...................................................................................................................13 Table 4-4: Primary Stress Limit Reinforcement Evaluation...................................................................14 Controlled Document

Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 6 List of Figures Page Figure 4-1: Reinforcement Area Diagram..............................................................................................16 Figure 4-2: J-Groove Weld plus Flaw Area Removed...........................................................................16 Controlled Document

Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 7 1.0 PURPOSE During the Fall 2021 outage (2R28) at Arkansas Nuclear One Unit 2 (ANO-2), an axial indication was discovered on the downhill side of Control Element Drive Mechanism (CEDM) Penetration No. 46 on the reactor vessel closure head (RVCH). Therefore, a half nozzle repair is performed, which removes and replaces the lower portion of the CEDM nozzle, using the inside diameter tempered bead (IDTB) weld process to attach the replacement nozzle to the RVCH and the remaining upper portion of the CEDM nozzle. The repair moves the pressure boundary from the existing J-Groove weld (JGW) to the new pressure boundary weld located in the RVCH penetration bore above the original JGW. The purpose of this evaluation is to perform a one cycle justification (OCJ) to assess the suitability of leaving a degraded, as-left J-Groove weld (ALJGW) in the RVCH following the CEDM nozzle repair.

The purpose of revision 001 is to add Appendix B to address contingency repairs identified in Reference 8.

2.0 ANALYTICAL METHODOLOGY Per IWB-3610(d), a component containing a flaw is acceptable for continued service during the evaluated time period if the following criteria are satisfied:

(1) the criteria of IWB-3611 or IWB-3612 (Reference 5),

(2) the primary stress limits of NB-3000 (Reference 6), assuming a local area reduction of the pressure retaining membrane that is equal to the area of the detected flaw(s) as determined by the flaw characterization rules of IWA-3000.

The evaluation time period for this calculation is one fuel cycle (18 months).

2.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612)

Per Section 4.7.4 of Reference 2, a comparative as-left J-groove weld (ALJGW) flaw evaluation shall be performed considering, geometry, materials, and transient loading conditions appropriate to the ANO-2 nozzle penetration No. 46 repair configuration to demonstrate acceptability for one-fuel cycle (18 months). The existing ALJGW flaw evaluation performed for a similar plant (will be referred to as Plant A in this document), which is used for this comparative analysis is documented in Reference 3. The general methodology of the analysis used in Reference 3 is summarized below:

Since a potential flaw in the JGW cannot be sized by currently available non-destructive examination techniques, it is assumed that the as-left condition of the remaining JGW includes degraded or cracked weld material extending through the entire JGW and Alloy 182 butter material. The purpose of this analysis is to determine from a fracture mechanics viewpoint the suitability of leaving degraded JGW material in the RVCH following repair of the nozzle. [

]

Controlled Document

Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 8 The fracture mechanics analysis is performed wherein stress intensity factors are calculated at increments of fatigue crack growth for comparison with the fracture toughness requirements of Section XI. Article IWB-3612 requires a safety fDFWRURI¥ for normal conditions to be used when comparing the applied stress intensity factor to the material fracture toughness. Calculations are performed for a postulated radial corner crack on the [

] side ( [

] ) of the CEDM nozzle.

Therefore, comparison of the ANO-2 specific design inputs to the existing Plant A ALJGW evaluation is done to demonstrate that the component containing the postulated flaw satisfies the acceptance criteria of IWB-3612 (Reference 5) per IWB-3610(d)(1), and thus it is acceptable for continued service during the evaluation time period (one fuel cycle).

This evaluation explicitly considers IWB-3612 (a) criteria for normal conditions only. IWB-3612 (b) criteria for emergency and faulted conditions are inferred to be met based on the discussion in Section 4.1.4, Item 3.

2.2 Primary Stress Limits (NB-3000)

Per IWB-3610(d)(2), primary stress limits of NB-3000 (Reference 6), assuming a local area reduction of the pressure retaining membrane that is equal to the area of the flaw, shall be satisfied. To evaluate this criterion, the reinforcement requirements of NB-3330 are evaluated, which compares the available reinforcement area at the location of the repaired nozzle with the area removed, including conservatively considering the entire area of the JGW and a bounding flaw growth associated with the life of the Plant A repair analysis and applying it to a one fuel cycle repair for ANO-2 penetration No. 46 repair configuration.

3.0 ASSUMPTIONS 3.1 Unverified Assumptions There are no unverified assumptions used in this evaluation.

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

Controlled Document

Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 9 4.0 CALCULATION 4.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612) Evaluation

[

]

As stated in Section 2.1, comparison of the ANO-2 nozzle penetration No. 46 repair configuration design inputs to the design inputs used in the Plant A ALJGW evaluation (Reference 3) is done to demonstrate the ANO-2 component containing the flaw satisfies the acceptance criteria of IWB-3612 (Reference 5). Thus, it is acceptable for continued service for one fuel cycle (18 months).

4.1.1 Geometry The geometry of the ANO-2 CEDM nozzle penetration No. 46 modification is compared to the geometry evaluated in an Plant A ALJGW analysis (Reference 3), which is summarized in Table 4-1. The following conclusions are made regarding the geometry of the analyzed configuration compared to the ANO-2 specific penetration:

1. [

] Therefore, it is concluded that the ANO-2 penetration is bounded by the Plant A penetration, in terms of the impact of geometry on [

]

2. [

] Therefore, in terms of [

] the ANO-2 configuration is bounded by Plant A.

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Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 10 Table 4-1: Geometry Comparison Description Equation ANO-2 Penetration No. 46 Plant A Penetration (CEDM)

Unit Reference Value Value ANO-2 Plant A Total Horizontal Distance to Penetration

' ¥'2+D22)

Nozzle Angle (Hillside)

VLQ-1(D/(R-tc))

Head Thickness at Penetration t

Radius to Base Metal R

R/t Ratio R/t Cladding Thickness tc CEDM Nozzle OD ODn Counterbore Db JGW Butter Layer Thickness tb Uphill, JGW Height, Chamfer to Butter-RVCH Interface (Plant A)

H1U Downhill, JGW Height, Chamfer to Butter-RVCH Interface (Plant A)

H1D Uphill, JGW Height, Clad to Chamfer (Plant A)

H2U Downhill, JGW Height, Clad to Chamfer (Plant A)

H2D Uphill, JGW Height, Clad to JGW-Butter Interface (ANO2)

H Downhill, JGW Height, Clad to JGW-Butter Interface (ANO2)

J Uphill, Equivalent Weld Height, Clad to Butter-RVCH Interface HWUH = H+tb (ANO2)

HWUH = H1U+H2U (Plant A)

Downhill, Equivalent Weld Height, Clad to Butter-RVCH Interface HWDH = J+tb (ANO2)

HWDH = H1D+H2D (Plant A) 4.1.2 Material The material aspects of the ANO-2 configuration are compared to the materials evaluated in the existing Plant A ALJGW analysis (Reference 3), which are summarized in Table 4-2. The following conclusions are made regarding the materials of the analyzed configuration compared to the ANO-2 specific penetration:

Document

Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 11

1. [

] Therefore, it is concluded that the ANO-2 penetration is equivalent to the Plant A penetration, in terms of the impact of [

]

2. [

] It is concluded that the yield strength is equivalent for SA-533 Gr. B CL. 1 material, applicable for both ANO-2 and Plant A.

3. [

] Since the ANO-2 RTNDT is less than the RTNDT value used for Plant A, the fracture toughness of the ANO-2 RVCH is bounded by the Plant A fracture toughness evaluation.

Table 4-2: Material [

]

Item ANO-2 Plant A Reference ANO-2 Plant A RVCH Material Cladding Material Existing Weld Material RVCH Yield Strength at 600 °F RVCH RTNDT 4.1.3 Weld Residual Stresses Consideration of weld residual stresses (WRS) for the Plant A evaluation is discussed in Section 5.0 of Reference 3. [

]

Comparing the repair drawings for ANO-2 (Reference 8) and Plant A (Reference 9), the original weld size for the ANO-2 JGW and butter is smaller than Plant A weld. Therefore, the WRS conclusions made for the Plant A evaluation would bound the ANO-2 configuration [

]

Effects of weld residual stresses plus [

] on the stress intensity factors are discussed in Appendix A.

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Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 12 4.1.4 Transient Loading Conditions

[

] stresses due to transient loading conditions and cycles are considered in the flaw growth evaluation.

The transient loading conditions applicable to ANO-2 and Plant A are defined in the following references.

ANO-2: Per Section 4.2 of Reference 2, the applicable transients, cycles, temperature and pressures for ANO-2 are per Appendix A of Reference 1, Table 1 of Reference 1 and Reference 12 (Section 5.2.1.5).

Plant A: Per Section 5.0 of Reference 3, transient stresses are obtained from the IDTB repair analysis (Reference 7). The transients used for this evaluation are listed in Table 5-1 of Reference 7, with pressure and temperature values for each transient defined in Table 5-2 through Table 5-6 of Reference 7, with timepoints selected for the Section III structural evaluation listed in Table 6-1 through Table 6-5 of Reference 7.

Reviewing the above inputs, the following conclusions are made regarding the transient loading conditions of the analyzed configuration compared to the ANO-2 specific penetration:

1. [

] Thus, it is concluded that the ANO-2 penetration is bounded by the Plant A penetration, in terms of the transient impact on the applied stresses.

2. [

] For all transients evaluated in Reference 3, the number of cycles evaluated for Plant A bound the cycles for ANO-2 for 1 fuel cycle (1.5 years).

[

]

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Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 13 3.

It is noted that Level C/D (Emergency/Faulted) requirements are not explicitly evaluated in Reference 3.

However, the IWB-3612 safety factor for Normal/Upset conditions LV¥ , YHUVXV¥ IRU

Emergency/Faulted conditions. Table 1 of Reference 2 states that maximum Level C/D pressure is

[

] which is only slightly higher than the maximum pressure evaluated in Reference 3 of

[

]

Therefore, it can be inferred that Level C/D criteria are met.

Table 4-3: Transient Cycles Analyzed Transient Plant A ANO-2 Cycles/ Year (Reference 3)

Cycles/

[

]

Cycles/ 60 Years (References 1 and 2)

Cycles/

1.5 Years 4.1.5 Review of ASME Section XI Criteria Reviewing the equations used in Reference 3, the following conclusions are made regarding the differences in Reference 3 compared to the equations applicable to ANO-2 using ASME Code,Section XI, Reference 5.

1. [

] Therefore, the evaluation contained in Reference 3 is conservative in this respect, per the requirements of Reference 5.

4.2 Primary Stress Limit Evaluation (NB-3000)

Per IWB-3610(d)(2), primary stress limits of NB-3000 (Reference 6), assuming a local area reduction of the pressure retaining membrane that is equal to the area of the flaw shall be satisfied. To evaluate this criterion, the reinforcement requirements of NB-3330 are evaluated, which compares the available reinforcement area at the location of the repaired nozzle with the area removed, including the entire area of the JGW and bounding flaw growth obtained from the existing Plant A analysis, and making it applicable for one fuel cycle for ANO-2.

Table 4-4 calculates the available reinforcement area (Ah), as depicted in Figure 4-1, and the area removed (Arem)

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Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 14 by the penetration bore and JGW plus flaw, as depicted in Figure 4-1 and Figure 4-2. Since the available reinforcement area is larger than the area removed, the reinforcement requirements of NB-3330 are met.

Table 4-4: Primary Stress Limit Reinforcement Evaluation Calculation Parameter Equation Value Unit Reference Tentative Pressure Thickness Design Pressure Inside radius of head Design stress intensity Tentative pressure thickness (NB-3324.2)

Removed Area due to Nozzle Bore Bore Diameter (Max)(1)

Plane distance of center of nozzle Tentative outside radius of head Vertical distance to inside radius Vertical distance to outer tentative thickness Depth of opening Opening area removed Removed Area due to JGW plus Crack Growth Maximum JGW Height Maximum Crack Growth + Compressive Zone Total height of flaw into RVCH Width of JGW from RVCH bore (at top of JGW)(2)

Total width of JGW + flaw into RVCH (at top)

JGW Angle Width of JGW angle area Nozzle Angle (Hillside)

Downhill area removed Total JGW + flaw removed area Removed Area Total removed area Limits of Reinforcement Radius RVCH thickness Nozzle thickness (no credit taken)

Mean radius of RVCH NB-3334.1(a)(1) Lw1 NB-3334.1(a)(2) Lw2 Distance to accommodate 100%

reinforcement NB-3334.1(b)(1)

NB-3334.1(b)(2)

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Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 15 Calculation Parameter Equation Value Unit Reference Distance to accommodate 2/3 reinforcement Length available for Reinforcement (Half distance to nearest opening)

Reinforcement Area Outer RVCH radius Vertical distance to outer RVCH Depth of reinforcement RVCH reinforcement area available Verify Reinforcement Area is greater than Removed Area Document

Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 16 Figure 4-1: Reinforcement Area Diagram Figure 4-2: J-Groove Weld plus Flaw Area Removed Controlled Document

Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 17 5.0

SUMMARY

OF RESULTS Per Section 4.1, it is demonstrated by comparative analysis that based on the evaluation of fatigue crack growth of the as-left J-Groove weld flaw into the low alloy steel RVCH, the ASME Code,Section XI, IWB-3612 requirements for fracture toughness are met for at least one fuel cycle (18 months) for the key transient inputs provided in Reference 1 for the evaluation. In addition, per Section 4.2, the primary stress limits considering reinforcement requirements of NB-3330 are met, considering a local area reduction in the pressure retaining membrane of the nozzle opening which includes the JGW and a conservatively bounding flaw size for the 18-month fuel cycle.

Based on the comparative analysis between ANO-2 and the existing Plant A ALJGW evaluation, the following conservatisms are noted for the ANO-2 configuration:

x The Plant A evaluation is based on the final flaw size at the predicted end life of the repair, which is

[

] The ANO-2 OCJ requires evaluation for only 1.5 years (18 months). Table 4-3 summarizes the transient cycles for each plant for the applicable number of years, which demonstrates the cycles considered for Plant A are conservative. See Section 4.1.4.

x The Plant A RVCH radius is about [

] than the ANO-2 RVCH radius, while the RVCH thickness is [

] which results in conservative primary stresses for ANO-2. In addition, the initial flaw depth for Plant A is [

] than the flaw depth for ANO-2. See Section 4.1.1.

x The Plant A HYDOXDWLRQXVHGWKHFUDFNDUUHVWIUDFWXUHWRXJKQHVV.Ia, instead of the crack initiation fracture WRXJKQHVV.Ic. In addition, the Plant A evaluation considers a RTNDT of [

] while a RTNDT of

[

] is applicable to ANO-2. Both factors result in a conservative calculation of the structural margins per the ASME code requirement per Reference 5 for ANO-2. See Sections 4.1.2 and 4.1.5.

x The reinforcement requirements of ASME NB-3330 consider the reduction in the nozzle opening area including the JGW and flaw growth area based on the flaw growth at the end life for Plant A repair (See Section 4.2), which as summarized above is very conservative for ANO-2.

All other items considered are comparable between ANO-2 and Plant A.

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Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 18

6.0 REFERENCES

References identified with an (*) are maintained within ANO-2 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.

[

]

4.

[

]

5.

ASME Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Division 1, 2007 Edition with 2008 Addenda.

6.

ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Facility Components, Division 1, 1992 Edition with no Addenda.

7.

[

]

8.

[

]

9.

[

]

10.

ASME Boiler and Pressure Vessel Code,Section II, Part D, 1992 Edition with no Addenda.

11.

Westinghouse Report, WCAP-18169-NP, Rev. 1, Arkansas Nuclear One Unit 2 Heatup and Cooldown Limit Curves for Normal Operation, June 2018.

12.

• Arkansas Nuclear One - Unit 2, Safety Analysis Report, Facility Operating License Number NPF-6, Docket Number 50-368, updated through Amendment 30.

13.

• ANO-2 Document M-2001-C2-26, Closure Head Penetrations. 234-761, Rev 3.

14.

[

]

15.

[

]

Document

Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 19 APPENDIX A: EFFECTS OF WRS + [

] ON SIF The purpose of this appendix is to provide additional discussion on the effects of the weld residual stresses (WRS) plus [

] on the stress intensity factors (SIFs).

Stress intensity factors are calculated for Plant A in Section 6.0 of Reference 3. Table 5 of Reference 3 contains SIF values due to effects of [

] only. As discussed in Section 4.1.3, [

]

Therefore, an additional existing ALJGW flaw evaluation performed for a similar plant in Reference 14 (referred to as Plant B in this appendix), is used for this comparative analysis.

Plant B RVCH and CRDM nozzle penetration key dimensions are listed as follows:

Spherical radius to cladding = [

]

Head thickness = [

]

Cladding thickness = [

]

Penetration bore = [

]

Horizontal Radius to Outermost Penetration = [

]

Based on the dimensions listed for ANO-2 in Table 4-1, the R/t ratio for ANO-2 is [

] than for Plant B and therefore, the hoop stresses due to pressure in the RVCH are [

] for ANO-2. In addition, Plant B RVCH and JGW filler and butter materials are [

]

With respect to JGW dimensions, Plant B has [

] JGW volume with an initial flaw depth of [

] which is [

] than ANO-2 initial flaw size [

]

[

] Table A-1 of Reference 14 calculates a SIF for the initial flaw depth due WRS of [

] Table A-7 of Reference 14 calculates the SIF due to [

] The total SIF at the initial flaw depth due to WRS plus

[

] is calculated to be [

] which is below the maximum allowable SIF value of 63.2 ksiin based on a required linear elastic fracture mechanics (LEFM) safety margin of 10 per IWB-3612 (Reference 5).

Based on the comparative analysis between ANO-2 and the existing Plant B ALJGW evaluation, it is concluded that the effects of WRS plus [

] on the initial flaw size for Plant B would bound the ANO-2 configuration.

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Document No. 32-9339466-001 PROPRIETARY ANO-2 CEDM Penetration 46 Modification As-Left J-Groove Weld One Cycle Justification - Non Proprietary Page 20 APPENDIX B:

JUSTIFICATION FOR CONTINGENCY REPAIRS The purpose of this appendix is to address the two contingency repairs identified in Reference 8. Section B.1 addresses the Contingency Shallow Cut repair and Section B.2 addresses the Contingency Overbore repair.

B.1 Contingency Shallow Cut Repair The Contingency Shallow Cut repair is identified in Steps 4A.1 through 4A.3 of Reference 8. [

]

[

] this repair does not impact the evaluation contained in the main body of this document, with the following considerations noted:

B.2 Contingency Overbore Repair The Contingency Overbore repair is identified in Steps 4C.1 through 4C.3 of Reference 8. [

] Therefore, the analysis detailed in Section 4.2 is still applicable and this contingency repair has no impact on the evaluation contained in the main body of this document.

[

]

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2 to 2CAN122103 OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO-2 Document Number 32-9339477-001 NON-PROPRIETARY

Page 1 of 15 0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY CALCULATION

SUMMARY

SHEET (CSS)

Document No.

32 9339477 001 Safety Related: Yes No Title OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary PURPOSE AND

SUMMARY

OF RESULTS:

Purpose:

This document presents a comparative One Cycle Justification (OCJ) for the Inner Diameter Temper Bead (IDTB) weld anomalies postulated for the repaired Control Element Drive Mechanism (CEDM) nozzle penetration No. 46 at Arkansas Nuclear One Unit 2 (ANO-2).

Summary: This document demonstrates by comparison to detailed analysis for the life of the repair of the IDTB weld anomalies (initial flaw depth up to [

] ) postulated at a similar location in a plant with comparable design and loading conditions.

The weld anomalies postulated at ANO-2 repaired CEDM nozzle penetration No. 46 with an IDTB weld procedure, is demonstrated to meet the acceptance criteria of IWB-3612 for normal/upset and emergency/faulted operating conditions. Thus, the modification is acceptable for one cycle (18 months) of operation.

Based on the comparative analysis between ANO-2 and an existing IDTB repair weld anomalies evaluation for a similar nuclear unit (Plant A), the following conservatisms are noted for the ANO-2 configuration:

x The Plant A evaluation is based on the final flaw size at the predicted end life of the repair, [

] years.

The ANO-2 OCJ requires evaluation for only 1.5 years (18 months). Table 4-3 summarizes the transient cycles for each plant for the applicable number of years, which demonstrates that the associated cycles considered in the reference analysis are conservative.

x The Plant A RVCH radius is about [

] than the ANO-2 RVCH radius, while the RVCH thickness is comparable for both plants, which results in conservative prediction of primary stresses for ANO-2.

x The Plant A evaluation considered used the [

] instead of the [

] In addition, the evaluation considered an RTNDT of [

] while an RTNDT of 10°F is applicable to ANO-2. Both factors result in conservative structural margins per the ASME code requirements for ANO-2.

x The Plant A evaluation also meets acceptance criteria of NB-3227.1 (shear stress in IDTB weld with postulated crack),

as well as acceptance criteria of IWB-3642 (sufficient loading capacity with full 360° radial-circumferential postulated flaw),

and requirement of IWB-3643 that flaws with depth greater than 75% of the wall thickness are unacceptable.

Revision 1 added Appendix A, which concluded that the proposed contingency repairs are still bounded by the comparative analysis for the OCJ.

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

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, AP 0402-01 requires that justification be provided.

THE DOCUMENT CONTAINS ASSUMPTIONS THAT SHALL BE VERIFIED PRIOR TO USE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT:

CODE/VERSION/REV CODE/VERSION/REV Yes No N / A Controlled Document

Document No. 32-9339477-001 0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 2 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 Name and Title (printed or typed)

Signature P/R/A/M and LP/LR Date Pages/Sections Prepared/Reviewed/Approved Samer Mahmoud, Advisory Engineer P

All Pages / All Sections Martin Kolar Principal Engineer R

All Pages / All Sections Ryan Hosler Supervisory Engineer A

All Pages / All Sections 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.

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Name (printed or typed)

Title (printed or typed)

Signature Date Comments N / A

 



 



 



 

 



Document

Document No. 32-9339477-001 0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 3 Record of Revision Revision No.

Pages/Sections/Paragraphs Changed Brief Description / Change Authorization 000 All Pages / All Sections Initial release of the document. The corresponding proprietary document is 32-9338933-000.

001 All The corresponding proprietary document is 32-9338933-001.

Pages 1 thru 4 Updated with revision.

Page 6 Added purpose for Revision 001.

Page 13 Updated Revision to References 7 and 9.

Added References 17, and 18.

Appendix A Added Appendix A.

Controlled Document

Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 4 Table of Contents Page SIGNATURE BLOCK................................................................................................................................2 RECORD OF REVISION..........................................................................................................................3 LIST OF TABLES.....................................................................................................................................5 1.0 PURPOSE.....................................................................................................................................6 2.0 METHODOLOGY..........................................................................................................................6 2.1 Postulated Flaws...............................................................................................................................6 2.2 Acceptance Criteria...........................................................................................................................7 3.0 ASSUMPTIONS............................................................................................................................7 3.1 Justified Assumptions........................................................................................................................7 3.2 Modeling Simplifications....................................................................................................................8 4.0 DESIGN INPUTS..........................................................................................................................8 4.1 Construction Materials.......................................................................................................................8 4.2 Geometry...........................................................................................................................................8 4.3 Transient Loading..............................................................................................................................9 4.4 Weld Residual Stresses..................................................................................................................11 4.5 Comparison of Flaw Evaluations.....................................................................................................11 4.5.1 Acceptance Criteria..........................................................................................................11 4.5.2 Crack Growth Rates.........................................................................................................12 5.0 RESULTS / CONCLUSION.........................................................................................................12

6.0 REFERENCES

............................................................................................................................13 APPENDIX A : CONTINGENCY REPAIRS EVALUATION...................................................................14 Controlled Document

Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 5 List of Tables Page Table 4-1: Materials of Construction.........................................................................................................8 Table 4-2: Dimension................................................................................................................................9 Table 4-3: List of Design Transient Cycles............................................................................................11 Document

Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 6 1.0 PURPOSE During the Fall 2021 outage (2R28) at Arkansas Nuclear One Unit 2 (ANO 2), an axial indication was discovered on the downhill side of Control Element Drive Mechanism (CEDM) Penetration No. 46 on the reactor vessel closure head (RVCH). As a mitigative measure, a half nozzle repair is being performed to remove and replace the lower portion of the CEDM nozzle. The inside diameter tempered bead (IDTB) weld procedure is used to attach the replacement nozzle to the RVCH and the remaining upper portion of the CEDM nozzle. The repair moves the pressure boundary from the existing J-Groove weld (JGW) to the new pressure boundary at the IDTB weld located in the RVCH penetration bore above the original JGW. During the welding process, weld anomalies may form at the triple point locations, where the three materials of the weld, nozzle and RVCH intersect. Two weld anomalies may potentially form at the upper and lower triple points. The upper triple point is defined as the intersection of the RVCH low alloy steel base material, the existing CEDM nozzle, and the [

]

weld. The lower triple point is defined as the intersection of the RVCH low alloy steel base material, the

[

] replacement CEDM nozzle, and the [

] weld. The purpose of this evaluation is to provide a one cycle justification (OCJ) for the acceptability of the CEDM nozzle repair using a fracture mechanics comparative analysis to assess the triple point weld anomalies impact on the structural integrity of the repair.

This justification focuses only on weld anomalies at pressure boundary formed by newly installed IDTB weld; the as left j-groove weld is addressed elsewhere.

The purpose of Rev. 001 is to address the contingency repair options. The evaluation is included in Appendix A of this document.

2.0 METHODOLOGY As required by Section 4.7.5 of Reference 9, the comparative weld anomaly analysis shall consider geometry, material, and transient loading conditions that are appropriate to the ANO-2 nozzle penetration No. 46 repair configuration. The evaluation shall demonstrate acceptability for one-fuel cycle by demonstrating that the postulated IDTB weld anomalies at the modified RVCH nozzle penetration meet the acceptance criteria of ASME Code Section XI (Reference 2), paragraph IWB-3612 for normal/upset and emergency/faulted conditions.

To conduct the comparative assessment for the OCJ, the fracture analysis of the IDTB repair weld triple point anomaly performed in Reference 12 for a similar plant is used as the basis for the comparison contained in the current document. The analyzed plant in Reference 12 will be referred to as Plant A throughout this document. The justification in this document is based on comparison of geometry, materials of construction, weld residual stresses, and operating loads, including possible margins gained by changes in acceptance criteria.

Note: no engineering software was used to generate results presented in this document.

2.1 Postulated Flaws The following flaws are postulated at both the upper and lower weld anomalies (triple points) locations.

All postulated flaws are [

] deep:

1.

Radial-circumferential with respect to the CEDM nozzle axis (see Figure A-3541-1 of Reference 3, full 360° circumferential flaw). Since this flaw reduces the cross section of the nozzle, it is required to demonstrate by limit load analysis that the remaining ligament has sufficient loading capacity (IWB-3642 of Reference 2).

2.

Radial-axial with respect to the CEDM nozzle axis (see Figure A-3560-1 of Reference 3).

3.

Cylindrical flaw, which is a flaw concentric with the CEDM nozzle; the flaw is located at the interface between the IDTB weld and closure head penetration surface.

Document

Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 7 2.2 Acceptance Criteria According to IWB-3612 (Reference 2), a flaw is acceptable if the applied stress intensity factor at the final flaw size is less than the fracture toughness (at the crack tip temperature) of the material with appropriate safety factors, and it satisfies the following criteria:

1.

For Level A and Level B (Normal and Upset) service level condition:

_ (_) < _/10 2.

For Level C and Level D (Emergency and Faulted) service level conditions:

_ (_) < _/2 Where KI(af) is the maximum applied stress intensity factor at the final flaw size af, and KIc is the initiation fracture toughness of the material at the corresponding crack tip temperature and irradiation level obtained from Figure A-4200-1 of Reference 2.

For the radial-circumferential (full 360° circumferential) flaw the paragraph IWB-3642 requires that remaining ligament has sufficient loading capacity.

For the cylindrical flaw, the requirement of NB-3227.1 shall be met.

Any flaw is less than 75% of the wall thickness (IWB-3643).

3.0 ASSUMPTIONS There are no unverified assumptions.

3.1 Justified Assumptions 1.

For fatigue crack growth calculations, cycles are assumed to accumulate at a linear rate. Based on plant operating experience, it can be demonstrated that linear rates generally envelope the actual accumulation rates observed for transients.

2.

Reference 15 states that the cycle counts for the remaining transients, particularly the [

] than the ANO-2 design by [

] please modify to

[

] cycles. It is noted that Section 5.2.1.5 of Reference 4 states that there are one million cycles of Normal Cyclic Variations (step changes) of [

] and [

] and that is selected based on one million cycles approximating an infinite number of cycles so that the limiting stress is the endurance limit. Based on experience with flaw growth calculations, [

] of [

]

and [

] do not significantly contribute to the flaw growth since the stress intensity factor range

.SURGXFHGE\\ these variations is less than [

] as determined by reviewing the data in References 10 and 126LQFH.LVWKHNH\\SDUDPHWHUWKDWGULYHVIDWLJXHFUDFNJURZWKHYHQFRQVLGHULQJ

[

] cycles, these variations would result in insignificant crack growth, for the one cycle justification herein, and are therefore not considered further in this comparative evaluation.

3.

Given the purpose of this document (one cycle justification) and that the postulated flaw propagates in [

] weld material, the stress corrosion cracking is considered negligible.

Controlled Document

Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 8 3.2 Modeling Simplifications 1.

The design of the CEDM housing nozzle modification includes [

]

IDTB weld. According to Section 5.3 of Reference 10, mechanical loads from the control element drive mechanisms are transmitted to the RV head [

] The [

] design feature [

] For this reason, the IDTB weld [

] Thus, this document treats [

]

4.0 DESIGN INPUTS 4.1 Construction Materials 1.

The material aspects of the ANO-2 configuration are compared to the materials evaluated in the Plant A analysis (Reference 12), which are summarized in Table 4-1. The following conclusions are made regarding the materials of the analyzed configuration compared to the repaired ANO-2 Nozzle No. 46 specific penetration. As shown in Table 4-1, the RV closure head base metal RTNDT for ANO-2 is taken from the P-T limits document (Reference 5); the Plant A RTNDT [

] Therefore, the RTNDT of the ANO-2 closure head is bounded by the Plant A analysis.

2.

The IDTB weld materials are considered identical for both ANO-2 and the Plant A analysis.

3.

Material of the CEDM nozzle is also identical for both ANO-2 and the Plant A analysis.

Table 4-1: Materials of Construction Item ANO-2 Design Reference Plant A Design Reference RV Material RV Material RTNDT CEDM Nozzle Material Replacement CEDM Nozzle Material IDTB Weld Material 4.2 Geometry The geometry comparison between the ANO-2 CEDM nozzle penetration No. 46 modification and the geometry evaluated in the Plant A analysis (Reference 12) is shown in Table 4-2. The following conclusions are made regarding the geometry of the analyzed configuration compared to the ANO-2 Nozzle No. 46 specific penetration:

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Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 9 1.

The RVCH base metal radius (Ri) for ANO-2 is approximately [

] smaller than the Plant A analysis radius ( [

] ). However, the RVCH base metal thickness (tRV) is similar ( [

] ), which produces a smaller R/t ratio for ANO-2 ( [

] ). Thus, the hoop stresses due to pressure in the RVCH are smaller for ANO-2, while the thermal stresses will be of similar magnitude due to comparable thicknesses (including cladding). In addition, the bore diameter and counterbore are comparable ( [

] ). Therefore, it is concluded that the ANO-2 penetration is bounded by the Plant A analysis, in terms of the impact of geometry on the applied primary and secondary stresses.

2.

The dimensions of the IDTB weld and relevant dimensions of the repaired nozzle are nearly identical. Thus, the dimensions of the IDTB weld and the nozzle have no impact on the analysis.

Table 4-2: Dimension Item Symbol ANO-2 Design Reference Plant A Design Reference Closure Head Inner Radius (base metal) [inch]

Ri Closure Head Thickness (base metal) [inch]

tRV Closure Head Unit Membrane Hoop Stress [psi]

M 1*R/(2*t)

Ratio of Membrane Hoop Stresses M M Nozzle Outer Diameter (CEDM) [inch]

do Nozzle Wall Thickness (CEDM) [inch]

tN calculated IDTB Weld Outer Diameter [inch]

dw IDTB Weld Thickness [inch]

tw calculated IDTB Weld Length [inch]

Lw 4.3 Transient Loading The Plant A analysis uses transient stresses developed in Reference 10 and it is recognized that unlike ANO-2 opening No. 46, the Plant A analysis covers [

] Therefore, the transient stresses are bounded by Plant A analysis of Reference 12.

The transient loading conditions applicable to ANO-2 and to the Plant A analysis are defined in the following references:

1.

ANO-2: Per Section 4.2 of Reference 9, applicable transients, cycles, temperature and pressures for ANO-2 are per Appendix A of Reference 15, Table 1 of Reference 15 and Reference 4 (Section 5.2.1.5).

2.

Plant A analysis: Per Section 5.0 of Reference 12, transient stresses are obtained from the IDTB repair analysis (Reference 10). The transients used for this evaluation are listed in Table 5-1 of Reference 10, with pressure and temperature values for each transient defined in Table 6-1 through Table 6-5 of Reference 7.

Reviewing the inputs provided in the above references, the following conclusions are made regarding the transient loading conditions of the analyzed configuration compared to the ANO-2 specific penetration:

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Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 10 I.

The pressure and temperature values specified in Appendix A of Reference 15 for ANO-2 are identical to the values listed in Table 6-1 through Table 6-5 of Reference 10, which were used in the Plant A analysis evaluation, with the following exception: Table 1 of Reference 15 states that the heat-up and cool-down rates specified in Appendix A of Reference 15 should be modified to [

] for both heat-up and cool-down excursions. Detail review of input data show that the Plant A analysis does consider [

] heat-up and cool-down rates. Therefore, it is concluded that the ANO-2 closure head penetration No. 46 is bounded by the penetration evaluated in the Plant A analysis.

II.

Table 4-3 lists the transient cycles applicable to ANO-2 for one fuel cycle (18 months), with comparison to the number of Plant A cycles for [

] of operation, which is the acceptable operating period (for the life of repair analysis) per Section 7.0 of Reference 11. For all transients evaluated in Reference 11, the number of cycles evaluated for Plant A bound the cycles for ANO-2 for one fuel cycle (1.5 years).

III.

Table 1 of Reference 15 states that the cycle counts for the remaining transients, particularly the [

] than the ANO-2 design by approximately [

] please modify

[

]. It is noted that Section 5.2.1.5 of Reference 12 states that there are one million cycles of Normal Cyclic Variations (step changes) of [

] and [

], and that is selected based on one million cycles approximating an infinite number of cycles so that the limiting stress is the endurance limit. Based on experience with flaw growth calculations, [

]

of [

] and [

] do not contribute to significant flaw growth since the stress intensity IDFWRUUDQJH.SURGXFHGE\\WKHVHYDULDWLRQVLVOHVVWKDQ [

], as determined by reviewing the data in References 10 and 126LQFH.LVWKHNH\\SDUDPHWHUWKDWGULYHVIDWLJXHFUDFNJURZWKHYHQ

considering [

] cycles, these variations would result in insignificant crack growth, for one fuel cycle, and are therefore not considered further in this comparative evaluation. See Section 3.1, Item #2.

IV.

It is noted that Level C/D (Emergency/Faulted) conditions were not explicitly evaluated in Reference 12.

However, the IWB- VDIHW\\ IDFWRU IRU 1RUPDO8SVHW FRQGLWLRQV LV ¥   YHUVXV ¥ 

for Emergency/Faulted conditions. Table 1 of Reference 15 states that the maximum Level C/D pressure is [

], which is approximately only [

] higher than the maximum pressure of [

]

evaluated in Reference 12. Considering that the Plant A analysis was developed on a closure head geometry where the primary membrane stress is more than [

] (Table 4-2) than at ANO-2 design, such increase in ANO-2 maximum Level C/D pressure is deemed bounded by Level A/B (Normal/Upset) for the purpose of the one cycle justification herein. Therefore, it is inferred that Level C/D criteria are met without specific evaluation.

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Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 11 Table 4-3: List of Design Transient Cycles 4.4 Weld Residual Stresses Consideration of weld residual stresses (WRS) in the Plant A analysis is discussed in Section 5.0 of Reference 12.

[

]

Comparing the repair drawings for ANO-2 (Reference 7) with the configuration in the Plant A analysis documented in Reference 6, shows that both weld sizes are identical. Therefore, the weld residual stresses used

[

] are applicable to the ANO-2 comparative analysis.

4.5 Comparison of Flaw Evaluations 4.5.1 Acceptance Criteria Comparing the equations used in Reference 12 to the equations applicable to ANO-2 using ASME Code,Section XI, Reference 2, the following conclusion is made:

Reference 12 uses the equation for [

] per Section XI, Article A-4200 when evaluating the IWB-3612 safety margins. [

] Therefore, the evaluation contained in Reference 12 is bounding in this respect per the requirements of Reference 2.

As demonstrated in Reference 16, the shear stress criteria of NB-3227.1 are met for the IDTB weld without flaw with substantial margin, therefore the reduction in cross section caused by flaw of up to [

] is met [

]

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Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 12 4.5.2 Crack Growth Rates The IDTB weld is made of [

], Step 3 in Reference 7). Although the 2007 edition of ASME BPV Code Section XI (Reference 2) [

] it states in paragraph C-8430 that crack growth rates for materials not covered by crack growth rates for austenitic and ferritic steels may be obtained from other sources. The growth rate curve should represent conservative values of fatigue crack growth rates for appropriate environment, cyclic loading and R ratios.

The analysis of Plant A uses [

] weld material. The 2021 edition of ASME BPV Code Section XI (Reference 3) provides [

] Therefore, the results of fatigue crack growth in Plant A analysis are applicable.

Considering that the fatigue crack growth in Plant A is shown as relatively small and that fatigue crack growth

[

] the analysis of Plant A valid for the life of repair is bounding.

5.0 RESULTS / CONCLUSION This document demonstrates by comparison to detailed analysis for the life of the repair of the IDTB weld anomalies (initial flaw depth up to [

] ) postulated at a similar location in a plant with comparable design and loading conditions. The weld anomalies postulated at ANO-2 repaired CEDM nozzle penetration No. 46 with an IDTB weld procedure, are demonstrated to meet the acceptance criteria of IWB-3612 for normal/upset and emergency/faulted operating conditions. Thus, the modification is acceptable for one cycle (18 months) of operation.

Based on the comparative analysis between ANO-2 and an existing IDTB repair weld anomalies evaluation for a similar nuclear unit (Plant A), the following conservatisms are noted for the ANO-2 configuration:

The Plant A evaluation is based on the final flaw size at the predicted end life of the repair, [

] years. The ANO-2 OCJ requires evaluation for only 1.5 years (18 months). Table 4-3 summarizes the transient cycles for each plant for the applicable number of years, which demonstrates that the associated cycles considered in the Plant A evaluation are conservative.

The Plant A RVCH radius is about [

] than the ANO-2 RVCH radius, while the RVCH thickness is comparable for both plants, which results in conservative primary stresses for ANO-2.

The Plant A evaluation used the [

] instead of the

[

] In addition, the Plant A evaluation considered an RTNDT of [

]

while an RTNDT of 10°F is applicable to ANO-2. Both factors result in conservative structural margins per the ASME code requirement for ANO-2.

The Plant A evaluation also meets acceptance criteria of NB-3227.1 (shear stress in IDTB weld with postulated crack), as well as acceptance criteria of IWB-3642 (sufficient loading capacity with full 360° radial-circumferential postulated flaw), and requirement of IWB-3643 that flaws with depth greater than 75% of the wall thickness are unacceptable.

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Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 13

6.0 REFERENCES

1.

Code of Federal Regulations, Title 10, Part 50.55a, Domestic Licensing of Production and Utilization Facilities, Codes and Standards, Federal Register Vol. 85, p. 65662, Oct. 16, 2020

2.

ASME Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Division 1, 2007 Edition with 2008 Addenda

3.

ASME Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components Division 1, 2021 Edition

4.

Arkansas Nuclear One, Unit 2, Safety Analysis Report, Facility Operating License Number NPF-6, Docket Number 50-368, updated through Amendment 30.

5.

Westinghouse Report WCAP-18169-NP, Rev.1, Arkansas Nuclear One Unit 2 Heatup and Cooldown Limit Curves for Normal Operation, June 2018

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

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Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 14 APPENDIX A:

CONTINGENCY REPAIRS EVALUATION A.1 Purpose This appendix addresses the impact of the proposed contingency repairs on the OCJ pertaining to the triple point weld anomaly fracture mechanics evaluation. Contingency repairs were proposed to remove an indication detected in the IDTB by the post weld NDE that was performed after the initial implementation of the half nozzle IDTB repair procedure. Two continency repairs were proposed and described in the design drawing (Reference 7)

A.1.1 Option 1: STEP 4A.1 through 4A.3-CONTINGENCY SHALLOW CUT Description Assessment Controlled Document

Document No. 32-9339477-001 PROPRIETARY OCJ IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non Proprietary Page 15 A.1.2 Option 2: STEPS 4C.1 through 4C.3 - CONTINGENCY OVERBORE Description Assessment A.2 Conclusion The relevant parameters to the IDTB weld anomaly FM evaluation include geometry, residual stresses, operating stresses, and acceptance criteria. As discussed in Sections A.1.1 and A.1.2, both contingency repairs have minor or no impact on these parameters. Thus, it is concluded that OCJ for the postulated weld anomalies FM evaluation in the main body of this document is valid for both contingency repairs.

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3 to 2CAN122103 ANO-2 CEDM IDTB Weld Repair One-Cycle Justification Document Number 32-9339421-001 NON-PROPRIETARY

Page 1 of 39 0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY CALCULATION

SUMMARY

SHEET (CSS)

Document No.

32 9339421 001 Safety Related: Yes No Title ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary PURPOSE AND

SUMMARY

OF RESULTS:

Purpose:

The purpose of this calculation is to qualify the Arkansas Nuclear One Unit 2 with a repaired control element drive mechanism (CEDM) inner diameter temper bead (IDTB) weld based on requirements specified in the Design Specification (Reference 1) for justifying one operating cycle.

The purpose of Revision 001 is to evaluate the contingent repairs shown in Appendix A and Appendix B.

Results:

The IDTB weld repair satisfies the applicable ASME Code requirements for one operating cycle.

The results from Revision 001 do not impact the conclusion of Revision 000.

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, AP 0402-01 requires that justification be provided.

THE DOCUMENT CONTAINS ASSUMPTIONS THAT SHALL BE VERIFIED PRIOR TO USE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT:

CODE/VERSION/REV CODE/VERSION/REV Yes No None Controlled Document

Document No. 32-9339421-001 0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 2 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 Name and Title (printed or typed)

Signature P/R/A/M and LP/LR Date Pages/Sections Prepared/Reviewed/Approved John Cosso Engineer I P

All Tomas Straka Advisory Engineer R

All Dave Skulina Supervisory Engineer A

All Don Kim Advisory Engineer M

All 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 (printed or typed)

Title (printed or typed)

Signature Date Comments N/A N/A N/A N/A N/A

 

 














 





 

 

Controlled Document

Document No. 32-9339421-001 0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 3 Record of Revision Revision No.

Pages/Sections/Paragraphs Changed Brief Description / Change Authorization 000 All Initial release. The corresponding proprietary document is 32-9338944-000.

001 Pages 1-5 Updated to address purpose of Revision 001.

Appendix A and Appendix B Added.

Section 8.0 Note added.

Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 4 Table of Contents Page SIGNATURE BLOCK................................................................................................................................2 RECORD OF REVISION..........................................................................................................................3 LIST OF TABLES.....................................................................................................................................6 LIST OF FIGURES...................................................................................................................................7

1.0 INTRODUCTION

...........................................................................................................................8 2.0 PURPOSE AND SCOPE...............................................................................................................8 3.0 ANALYTICAL METHODOLOGY...................................................................................................8 4.0 ASSUMPTIONS............................................................................................................................8 4.1 Unverified Assumptions.....................................................................................................................8 4.2 Justified Assumptions........................................................................................................................8 5.0 DESIGN INPUTS..........................................................................................................................9 5.1 Geometry...........................................................................................................................................9 5.2 Materials..........................................................................................................................................10 5.2.1 Replacement Guide Material Justification........................................................................10 6.0 CALCULATIONS.........................................................................................................................10 6.1 Primary Stress Evaluation...............................................................................................................11 6.1.1 ASME Code Allowable Stresses.......................................................................................12 6.1.2 Loading.............................................................................................................................12 6.1.3 Primary Stress Intensity and Pure Shear Stress Calculation...........................................14 6.1.4 Triaxial Stress Calculation................................................................................................17 6.2 Weld Size Requirements.................................................................................................................17 6.3 Tentative Thickness Calculation.....................................................................................................19 6.3.1 RVCH................................................................................................................................19 6.3.2 CEDM Nozzle...................................................................................................................19 6.4 Reinforcement Requirements.........................................................................................................20 6.4.1 Removed Area..................................................................................................................20 6.4.2 Limits of Reinforcement....................................................................................................21 6.4.3 Available Reinforcement Area..........................................................................................22 6.5 Stress and Fatigue Usage Criteria..................................................................................................23 7.0 RESULTS

SUMMARY

AND CONCLUSION...............................................................................23

8.0 REFERENCES

............................................................................................................................23 APPENDIX A : SHALLOW CUT REPAIR CONTINGENCY..................................................................24 Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Table of Contents (continued)

Page Page 5 APPENDIX B : OVERBORE REPAIR CONTINGENCY.........................................................................32 Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 6 List of Tables Page Table 5-1: Material Properties................................................................................................................10 Table 6-1: ASME Code Allowable Stresses for Design Conditions (Level A and B).............................12 Table 6-2: ASME Code Allowable Stresses for Emergency Conditions (Level C).................................12 Table 6-3: ASME Code Allowable Stresses for Faulted Conditions (Level D)........................................12 Table 6-4: CEDM Loads (Reference 2).................................................................................................14 Table 6-5: Local Piping Loads Under Service Levels............................................................................14 Table 6-6: Primary Stress Intensities at IDTB Weld...............................................................................15 Table 6-7: Pure Shear Stresses at IDTB Weld......................................................................................16 Table 6-8: Primary Stress Intensities at CEDM Nozzle.........................................................................16 Table 6-9: IDTB Weld Size Results.......................................................................................................18 Table A-1: Primary Stress Intensities at IDTB Weld...............................................................................27 Table A-2: Pure Shear Stresses at IDTB Weld.......................................................................................27 Table A-3: Primary Stress Intensities at CEDM Nozzle..........................................................................28 Table A-4: IDTB Weld Size Results........................................................................................................29 Table B-1: Primary Stress Intensities at IDTB Weld...............................................................................34 Table B-2: Pure Shear Stresses at IDTB Weld.......................................................................................34 Table B-3: Primary Stress Intensities at CEDM Nozzle..........................................................................35 Table B-4: IDTB Weld Size Results........................................................................................................36 Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 7 List of Figures Page Figure 5-1: CEDM IDTB Weld Repair......................................................................................................9 Figure 6-1: Analysis Locations...............................................................................................................11 Figure 6-2: Location of External Loads..................................................................................................13 Figure 6-3: NB-4244(d)-1(c)...................................................................................................................17 Figure 6-4: Weld Size Location..............................................................................................................18 Figure 6-5: Reinforcement Area Calculation..........................................................................................20 Figure A-1: Replacement CEDM Nozzle Thickness..............................................................................25 Figure A-2: NB-4244(d)-1(c)...................................................................................................................29 Figure A-3: Weld Size Location..............................................................................................................30 Figure B-1: NB-4244(d)-1(c)...................................................................................................................36 Figure B-2: Weld Size Location..............................................................................................................37 Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 8

1.0 INTRODUCTION

During the Fall 2021 outage (2R28), as a part of the ultrasonic examination (UT) for the in-service inspection at Arkansas Nuclear One Unit 2 (ANO 2), an axial indication was discovered on the downhill side of Control Element Drive Mechanism (CEDM) Penetration No. 46 on the reactor vessel closure head. Subsequently, an outside diameter (OD) surface eddy current testing (ET) was performed to confirm the presence of a surface indication; furthermore, an outside diameter surface dye penetrant test (PT) in the area of the UT indication confirmed a surface breaking indication. An Inner Diameter Temper Bead (IDTB) weld repair is being performed per Reference 1.

CEDM #46 is located in the reactor vessel closure head (RVCH) at x, y coordinates of [

]

(Reference 2). The original nozzle is connected to the RV head with a partial penetration J-groove weld made on the inside of the RV head. The modification consists of the removal and replacement of the lower portion of the existing CEDM nozzle (including nozzle guide) at CEDM penetration #46. The upper portion of the nozzle will remain in place. The modification removes an existing portion of the pressure boundary partial penetration J-groove weld on the inside of the RVCH. The new pressure boundary weld is established in the RVCH penetration bore above the original weld.

2.0 PURPOSE AND SCOPE This calculation justifies plant operation of one cycle with the repaired penetration based on Section III of the ASME Boiler & Pressure Vessel Code (Reference 3). A subsequent analysis will demonstrate acceptability of the repaired penetration for operation beyond one cycle.

3.0 ANALYTICAL METHODOLOGY Compliant with the ASME Boiler & Pressure Vessel Code (Reference 3) the following steps will be performed to demonstrate the acceptability of the IDTB weld repair:

x Primary stress criteria will be evaluated at the new IDTB weld and existing CEDM nozzle x

Reinforcement requirements will be evaluated due to the removal of area within the RVCH x

Acceptability of the new IDTB weld configuration with respect to the ASME Code dimensional requirements will be determined x

A qualitative assessment of the primary + secondary stress (P+Q) as well as fatigue will be made regarding a single cycle of operation (18 months) 4.0 ASSUMPTIONS 4.1 Unverified Assumptions There are no unverified assumptions used in this calculation.

4.2 Justified Assumptions Minor justified assumptions are stated throughout the calculation as used.

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Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 9 5.0 DESIGN INPUTS 5.1 Geometry The repair is illustrated in Figure 5-1. Key nominal dimensions are listed below in inches.

RV head inside radius to base metal (Reference 2)

RV head thickness at penetration #46 (Reference 2)

RV head cladding thickness (Reference 2)

Original CEDM nozzle OD (Reference 2)

Original CEDM nozzle ID (Reference 2)

IDTB Weld Length (Reference 4)

IDTB Weld OD (Reference 4)

IDTB Weld ID (Reference 4)

Figure 5-1: CEDM IDTB Weld Repair Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 10 5.2 Materials The materials designations of the sub-components are:

RV head =

(Reference 2)

Original CEDM housing nozzle =

(Reference 2)

Cladding =

(Reference 2)

IDTB Repair weld (1) =

(Reference 4)

Replacement lower portion of CEDM =

(Reference 1)

J-groove weld =

(Reference 2)

Replacement guide (2) =

(Reference 1)

Notes:

(1) The allowable stress value used for the IDTB weld are taken to be [

]

(2) The replacement guide material differs from the replacement CEDM material. See Section 5.2.1 for further explanation.

Table 5-1 lists the material properties for the materials used in the analysis at the design temperature. Sm values come from Reference 6. Sy and Su values come from Reference 7. Note that both materials share the same Sm and Su values.

Table 5-1: Material Properties Material Sm (psi)

Sy (psi)

Su (psi)

SB-166 23,300 35,000 80,000 SB-167 23,300 30,000 80,000 SA-533 Gr. B Cl. 1 26,700 Not used Not used 5.2.1 Replacement Guide Material Justification The purpose of this section is to ensure the threaded connection between the replacement CEDM nozzle and replacement guide are not compromised due to the material differences. The two components have different thermal expansion coefficients, therefore, during thermal expansion they expand at different rates. By inspection, the thermal expansion of the replacement guide will expand faster than the replacement CEDM nozzle. Using Figure 5-1, the replacement guide will expand faster than the replacement nozzle making the threaded connection tighter. In addition, per Reference 4, once the guide is fully seated on the end of the nozzle, they are welded together to ensure the guide does not become unthreaded during operation.

6.0 CALCULATIONS All calculations were completed in excel file OCJ_IDTB Weld_ANO2. This file can be found in Framatome Inc ColdStor system in folder cold/General-Access/32/32-9000000/32-9338944-000.

Note that all dimensions in the following sections will use the worst-case dimension, accounting for tolerances stated on the design drawings, unless otherwise stated. If no tolerance is listed the nominal value is used.

Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 11 In addition, similar analyses of RVCH IDTB repairs performed for other plants have successfully met all ASME Section III criteria in the required follow-on analysis for the life of repair.

6.1 Primary Stress Evaluation Per Reference 1, a primary stress intensity evaluation is required using the criteria of Reference 3. The evaluation checks stresses on the IDTB weld and the CEDM nozzle due to internal pressure and external loads. Stresses at each service level are evaluated. Figure 6-1 describes the locations analyzed. Conservatively, the nozzle analysis location uses the same moment arm as the weld analysis.

Figure 6-1: Analysis Locations Based on the slow corrosion rate [

] computed in Reference 5, it is concluded that corrosion has an insignificant impact on the CEDM nozzle and the weld. However, the effects of corrosion are considered in the reinforcement requirements only for the RVCH as it is made of low alloy steel. The length of time used in the calculations considering corrosion is [

]

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Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 12 6.1.1 ASME Code Allowable Stresses Allowable stresses are calculated at the design temperature of [

] using Reference 6.

Table 6-1: ASME Code Allowable Stresses for Design Conditions (Level A and B)

Location Membrane (ksi)

Membrane + Bending (ksi)

Pure Shear (ksi)

Sm 1.5Sm 0.6Sm IDTB Weld and CEDM 23.30 34.95 13.98 The allowable stresses for Normal (Level A) and Upset (Level B) Conditions are per NB-3222 and NB-3223 respectively, Reference 3. Level A and B stress are bounded by the design conditions. Note that Reference 3 states that Level B allowable stress intensity values shall be increased to 110% of the values given on Figure NB-3221-1. Conservatively, this is not considered. The allowable stresses for pure shear are per NB-3227.2.

Table 6-2: ASME Code Allowable Stresses for Emergency Conditions (Level C)

Location Membrane (ksi)

Membrane + Bending (ksi)

Pure Shear (ksi) 1.2Sm 1.8Sm 1.2(0.6Sm)

IDTB Weld and CEDM 27.96 41.94 16.78 The allowable stresses for emergency (Level C) Conditions are per NB-3224, Reference 3.

Table 6-3: ASME Code Allowable Stresses for Faulted Conditions (Level D)

Location Membrane (ksi)

Membrane + Bending (ksi)

Pure Shear (ksi) 2.4Sm 1.5(2.4Sm) 0.42Su (1)

IDTB Weld and CEDM 55.92 83.88 33.60 (1) Su value is from Table I Reference 7.

The allowable stresses for Faulted (Level D) Conditions are per NB-3225 and Appendix F, Reference 3. Note that the primary side hydrostatic test condition is not checked since it is not expected to be performed anymore.

6.1.2 Loading The external mechanical loadings are specified in Reference 2. The internal pressure used in the analysis is

[

] specified in Reference 1 as design pressure. Based on Reference 2, the external loads are applied at the RVCH outer surface and CEDM nozzle junction. Conservatively, the uphill side of the CEDM nozzle and RVCH outer surface location is used as the point the external loads act on. Figure 6-2 shows the location the external loads act on.

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 13 Figure 6-2: Location of External Loads The uphill side location was calculated to be [

] away from the weld, this is the value used as the moment arm. Applicable loads from Reference 2 are collected in Table 6-4 where the direction A is the nozzle axial positive upwards, B is horizontal positive outwards, and C is determined by the right-hand rule.

Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 14 Table 6-4: CEDM Loads (Reference 2)

Load Case FA (lbs) FB (lbs) FC (lbs) MA (in-lbs) MB (in-lbs) MC (in-lbs)

The load combinations are specified in Reference 2. For primary stress evaluation, the load combinations are listed as follows:

• SRSS = square root sum of the squares Table 6-5 calculates the services loads based on the loading combinations, where x, y. and z are the directions a, b, and c in Table 6-4, respectively. Cap axial force due to pressure is included in service loads. Conservatively, deadweight is considered to act in the same direction as pressure and seismic loads.

Table 6-5: Local Piping Loads Under Service Levels Service Load FA (lbs)

FB (lbs)

FC (lbs)

MA (in-lbs)

MB (in-lbs)

MC (in-lbs) 6.1.3 Primary Stress Intensity and Pure Shear Stress Calculation The primary stress intensities are calculated in the excel file at the inner radius, mean radius, and outer radius not including corrosion. The pure shear stresses are calculated in the excel file only at the outer radius of the IDTB weld, this calculation includes the effects of corrosion. The corrosion reduces the length of the weld along the head, ultimately reducing the area. All values are listed below including the stress ratio, which is calculated as shown below.

=

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 15 Below are the general equations used to calculate the stresses:

Axial stress:

=

+

()

+

Hoop stress:

=

(

+ 1)

Radial stress:

=

(

1)

Shear stresses:

=

+

, = = 0 All the calculated stresses conservatively do not consider the support of the RVCH. The original CEDM nozzle is roll expanded, therefore the IDTB weld and nozzle only see a fraction of the stresses listed in Table 6-6, Table 6-7, and Table 6-8.

Note membrane stresses are typically listed as average values. Being that membrane stresses are listed at all three locations they only need to meet criteria at the mean radius location.

Table 6-6: Primary Stress Intensities at IDTB Weld Service Level Location Membrane

+

Bending (psi)

Stress Ratio Membrane (psi)

Stress Ratio Level A Inside Outside Mean Level B Inside Outside Mean Level C Inside Outside Mean Level D Inside Outside Mean Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 16 Table 6-7: Pure Shear Stresses at IDTB Weld Service Level Location Shear Stress (psi)

Stress Ratio Level A Weld OD Level B Weld OD Level C Weld OD Level D Weld OD Table 6-8: Primary Stress Intensities at CEDM Nozzle Service Level Location Membrane

+

Bending (psi)

Stress Ratio Membrane (psi)

Stress Ratio Level A Inside Outside Mean Level B Inside Outside Mean Level C Inside Outside Mean Level D Inside Outside Mean Both the IDTB weld and the CEDM nozzle met the primary stress intensity requirements at all locations and all service levels. In addition, the IDTB weld meets the pure shear requirements at all service levels.

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 17 6.1.4 Triaxial Stress Calculation To meet the requirement, Reference 3 states that the algebraic sum of the three primary stresses shall not exceed 4Sm, expect for service level D.

4= 4(23,300 ) = 93,200 The three primary stresses that bound the IDTB weld and CEDM nozzle are:

[

] The algebraic sum of the three primary stresses is

[

] Since [

] the triaxial stress requirement is met.

6.2 Weld Size Requirements Weld Size (NB-3352.4, Reference 3)

This weld needs to satisfy the minimum dimension requirements of FIG. NB-4244(d)-1(c) per Reference 3. FIG.

NB-4244(d)-1(c) is shown in Figure 6-3. Reference 4 states the CEDM nozzle has an OD of [

]

and ID of [

] which results in a nominal thickness of [

] With the nominal thickness the weld size requirements can be determined. Table 6-9 lists the IDTB weld size requirements and results. Figure 6-4 shows how the weld size results are applicable to the requirements of NB-4244(d)-1(c).

Figure 6-3: NB-4244(d)-1(c)

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 18 Table 6-9: IDTB Weld Size Results IDTB Weld Formula Description Design Value Allowable Value Criteria met?

Yes Yes Yes Figure 6-4: Weld Size Location Nozzle Diametric Clearance (NB-3337.3(a), Reference 3)

For a nozzle OD greater than 4 the maximum diametric clearance of 0.030 per NB-3337.3(a). Per Reference 4 the replacement nozzle OD is [

] and the bore ID is [

] The equation below solves for the nozzle diametric clearance.

=

Considering,

[

]

[

]

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 19 The nozzle diametric requirement is met. In addition, the original nozzle is roll expanded and therefore meets the requirements as well.

6.3 Tentative Thickness Calculation Tentative Thickness Calculation (NB-3324.1)

The tentative thickness calculation of the RVCH is determined by the methodology specified in NB-3324 of the ASME boiler and Pressure Vessel Code (Reference 3). As stated in the article, except in local areas, the wall thickness of a vessel shall never be less than that obtained from the formula in NB-3324.1 for cylindrical shells and NB-3324.2 for spherical shells.

NB-3324.1 (Cylindrical Shells):

=

NB-3324.2 (Spherical Shells):

=

Where:

t = Tentative thickness, in.

P = Design pressure, psi R = Inside radius, in.

Sm = Design stress intensity value, psi 6.3.1 RVCH Per Reference 2 the original RVCH inner radius is [

] (including maximum tolerance) and the RVCH thickness is [

] Using the spherical shell formula with P [

] and Sm

[

], the tentative pressure thickness is:

Comparing the design thickness to the tentative thickness.

Therefore, the tentative thickness requirement is met.

6.3.2 CEDM Nozzle Per Reference 4 the original nozzle OD is [

] and ID is [

] (including maximum tolerance). Using the cylindrical shell formula with P [

], R [

] and Sm

[

] the tentative pressure thickness is:

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 20 The nozzle wall thickness considering the nominal dimensions is:

Therefore, the tentative thickness requirement is met.

6.4 Reinforcement Requirements Due to the area removal in the RVCH to accommodate the IDTB weld repair an evaluation is required to determine the reinforcement requirements are met.

The calculation for the minimum required area of reinforcement is based on the methodology listed in NB-3330 Reference 3. Figure 6-5 describes the dimensions and areas being analyzed.

Figure 6-5: Reinforcement Area Calculation 6.4.1 Removed Area The maximum penetration diameter including the effects of corrosion and dimensioning tolerances is:

do

[

]

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 21 This includes the corrosion rate of [

] from Reference 5 over the life of [

] (end of the plants license).

The plane distance to the center of the penetration No. 46 (C) can be calculated by the x and y coordinated in Reference 2 to be:

C

[

]

The inside radius of the head (Ri) is [

] (Reference 2).

The mean radius of head:

R

= Ri + t/2

[

]

The minimum required thickness of the RVCH was previously calculated to be:

tt

[

]

The outside radius of the head to the required head thickness (Rt) is:

Rt

= Ri + tt

[

]

The vertical distance from center of head-to-head inside radius (Hi) is:

Hi

= (Ri2 - C2)0.5

[

]

The vertical distance from center of head to the outside radius of the required head thickness (Ht) is:

Ht

= (Rt2 - C2)0.5

[

]

Removed area due to opening (Arem) is:

Arem

= (Ht - Hi)*do

[

]

6.4.2 Limits of Reinforcement Reference 3 establishes the limits of the reinforcement area along and normal to the vessel surface. The limits of reinforcement, measured along the mid surface of the nominal wall thickness, shall meet the following:

A. One hundred percent of the required reinforcement shall be within a distance on each side of the axis of the opening equal to the greater of the following:

a.

NB-3334.1(a)(1), Diameter of finished opening, do [

]

b.

NB-3334.1(a)(2), Sum of radius of finished opening, thickness of nozzle (conservatively equal to zero) and vessel wall which equals [

]

B. Two thirds of the required reinforcement shall be within a distance on each side of the axis of the opening equal to the greater of the following:

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 22 a.

NB-3334.1(b)(1): r+0.5 (Rt)0.5 Where R is the mean radius of head, t is the nominal vessel wall thickness, and r is the radius of the finished opening in the corroded condition:

r+0.5 (Rt)0.5 [

]

b.

NB-3334.1(b)(2): r+2(t + tn)/3 Where r is the radius of the finished opening in the corroded condition, tn is the nozzle thickness (conservatively equal to zero) and t is the nominal vessel wall thickness:

r+2(t+ tn)/3 [

]

Furthermore, the ASME code prohibits the same reinforcing material from being applied to more than one opening and requires that one half of the reinforcing material lie on each side of the opening. Therefore, the reinforcement limit is restricted to one-half of the distance between similar adjacent penetrations. Reference 2 shows shortest distance to another opening from penetration No. 46 is [

] Accordingly, the limit of reinforcement Lr is [

]

6.4.3 Available Reinforcement Area The available area of reinforcement is shown in Figure 6-5 and is calculated as follows:

The outside radius of the RVCH (Ro) is:

Ro

= Ri + t

[

]

The vertical distance from center of head to outside radius of the head (Ho) is:

Ho

= (Ro2 - C2)0.5

[

]

The thickness of the RVCH (tr) that was not removed is:

tr

= Ho - Ht

[

]

The area of the original flawed J-groove weld needs to be account for as area removed. It is conservatively estimated to be 3 in2. Conservatively, the IDTB weld is not being credited for area of reinforcement.

Ajgw

[

]

Total area removed is:

Aremoved = Arem + Ajgw

[

]

Considering there are no other repairs in the vicinity of nozzle #46, the total area of reinforcement is:

Arein

= 2*tr*(Lr - (do/2))

[

]

Since the total reinforced area is greater than the total area removed the reinforcement requirements are met.

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 23 6.5 Stress and Fatigue Usage Criteria The ASME Code places a limit on the primary plus secondary stress intensity in order to prevent failure by excessive distortion caused by the repeated application of loads. The Code also limits total stresses, through the cumulative fatigue usage factor, in order to prevent failure by fatigue. Primary plus secondary stress intensity and fatigue for one cycle are qualitatively assessed. In addition, the presence of differential thermal expansion is discussed in Section 5.2.1. The 3Sm stress check will be performed as part of the required subsequent full Section III analysis.

[

]

7.0 RESULTS

SUMMARY

AND CONCLUSION The repair of CEDM nozzle #46 is acceptable for one cycle of operation.

8.0 REFERENCES

Note: The references in this section are at the appropriate revision level for the main body results. There are additional references in Appendix A and Appendix B. The references in the appendices are updated to the current revision level and are at the appropriate revision level for the appendix results.

1.

Framatome Document 08-9338577-000, ANO-2 CEDM Penetration #46 Modification.

2.

Framatome Document 38-2201963-001, Design Input Record: LTR-SDA-21-083 Rev. 5.

3.

ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Facility Components, Division I, 1992 with no Addenda.

4.

Framatome Drawing 02-9338578-E-000, ANO-2 CEDM Nozzle Pen. #46 IDTB Weld Repair.

5.

Framatome Document 51-9338948-000, Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair.

6.

ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Vessels, Division 1, 1968 Edition with Addenda through Summer 1970.

7.

ASME Boiler and Pressure Vessel Code,Section II, Material Specifications Part B - Nonferrous, 1968 Edition with Addenda through Summer 1970.

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 24 APPENDIX A:

SHALLOW CUT REPAIR CONTINGENCY A.1 Introduction CEDM penetration #46 at ANO-2 underwent an IDTB weld repair. During the repair weld inclusions were found.

Consequently, addition analysis is necessary. This analysis is for the shallow cut repair contingency.

A.2 Purpose The purpose of this calculation is to re-evaluate the ASME code requirements per Reference A1 based on the updated shallow cut contingency dimensions in step 4A per Reference A2.

A.3 Methodology The methodology is the same as the original analysis, contained the main body of the document. Herein referred to as the original analysis.

A.4 Assumptions The assumptions are the same as the original analysis.

A.5 Design Inputs A.5.1 Geometry Most of the geometry is the same as the original analysis. The geometry that is not the same is listed below.

IDTB Weld ID:

[

]

(Reference A2)

It is worth noting that the shallow cut repair does cut into the replacement CEDM nozzle ID. This affectively reduced the thickness of the replacement CEDM nozzle. Per Reference A2, by inspection, the cut area is not the thinnest part of the replacement CEDM nozzle. Therefore, no additional analysis is required. See Figure A-1 for a visual of the replacement CEDM nozzle thickness.

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 25 Figure A-1: Replacement CEDM Nozzle Thickness A.5.2 Materials The materials are the same as the original analysis.

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 26 A.6 Calculations All calculations were completed in excel file shallow cut_REVISED_OCJ_IDTB Weld_ANO2. This file can be found in Framatome Inc ColdStor system in folder cold/General-Access/32/32-9000000/32-9338944-001.

Note that all dimensions in the following sections will use the worst-case dimension, accounting for tolerances stated on the design drawings, unless otherwise stated. If no tolerance is listed the nominal value is used.

In addition, similar analyses of RVCH IDTB repairs performed for other plants have successfully met all ASME Section III criteria in the required follow-on analysis for the life of repair.

A.6.1 Primary Stress Evaluation The primary stress evaluation uses the same methodology as the original analysis.

A.6.1.1 ASME Code Allowable Stresses All the information in the ASME code allowable stresses section in the original analysis is applicable to this analysis.

A.6.1.2 Loading All the information in the loading section in the original analysis is applicable to this analysis.

A.6.1.3 Primary Stress Intensities and Pure Shear Calculation The primary stress intensities are calculated in the excel file at the inner radius, mean radius, and outer radius not including corrosion. The pure shear stresses are calculated in the excel file only at the outer radius of the IDTB weld, this calculation includes the effects of corrosion. The corrosion reduces the length of the weld along the head, ultimately reducing the area. All values are listed below including the stress ratio, which is calculated as shown below.

=

Below are the general equations used to calculate the stresses:

Axial stress:

=

+

()

+

Hoop stress:

=

(

+ 1)

Radial stress:

=

(

1)

Shear stresses:

=

+

, = = 0 All the calculated stresses conservatively do not consider the support of the RVCH. The original CEDM nozzle is roll expanded, therefore the IDTB weld and nozzle only see a fraction of the stresses listed in Table A-1, Table A-2, and Table A-3.

Note membrane stresses are typically listed as average values. Being that membrane stresses are listed at all three locations they only need to meet criteria at the mean radius location.

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 27 Table A-1: Primary Stress Intensities at IDTB Weld Service Level Location Membrane

+

Bending (psi)

Stress Ratio Membrane (psi)

Stress Ratio Level A Inside Outside Mean Level B Inside Outside Mean Level C Inside Outside Mean Level D Inside Outside Mean Table A-2: Pure Shear Stresses at IDTB Weld Service Level Location Shear Stress (psi)

Stress Ratio Level A Weld OD Level B Weld OD Level C Weld OD Level D Weld OD Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 28 Table A-3: Primary Stress Intensities at CEDM Nozzle Service Level Location Membrane

+

Bending (psi)

Stress Ratio Membrane (psi)

Stress Ratio Level A Inside Outside Mean Level B Inside Outside Mean Level C Inside Outside Mean Level D Inside Outside Mean Both the IDTB weld and the CEDM nozzle met the primary stress intensity requirements at all locations and all service levels. In addition, the IDTB weld meets the pure shear requirements at all service levels.

A.6.1.4 Triaxial Stress Calculation To meet the requirement, Reference A1 states that the algebraic sum of the three primary stresses shall not exceed 4Sm, expect for service level D.

4= 4(23,300 ) = 93,200 The three primary stresses that bound the IDTB weld and CEDM nozzle are: [

] The algebraic sum of the three primary stresses is [

] Since

[

] the triaxial stress requirement is met.

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 29 A.6.2 Weld Size Requirements This weld needs to satisfy the minimum dimension requirements of FIG. NB-4244(d)-1(c) per Reference A1.

FIG. NB-4244(d)-1(c) is shown in Figure A-2. Reference A2 states the original CEDM nozzle has an OD of

[

] and ID of [

] which results in a nominal thickness of [

]

With the nominal thickness the weld size requirements can be determined. Table A-4 lists the IDTB weld size requirements and results. Figure A-3 shows how the weld size results are applicable to the requirements of NB-4244(d)-1(c).

Figure A-2: NB-4244(d)-1(c)

Table A-4: IDTB Weld Size Results IDTB Weld Formula Description Design Value Allowable Value Criteria met?

Yes Yes Yes Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 30 Figure A-3: Weld Size Location Nozzle Diametric Clearance (NB-3337.3(a), Reference A1)

For a nozzle OD greater than 4 the maximum diametric clearance of 0.030 per NB-3337.3(a). Per Reference A2 the replacement nozzle OD is [

] and the bore ID is [

] The equation below solves for the nozzle diametric clearance.

[

]

Considering,

[

]

The nozzle diametric requirement is met. In addition, the original nozzle is roll expanded and therefore meets the requirements as well.

A.6.3 Tentative Thickness Calculation Tentative Thickness Calculation (NB-3324.1)

The tentative thickness calculation of the RVCH is determined by the methodology specified in NB-3324 of the ASME boiler and Pressure Vessel Code (Reference A1). As stated in the article, except in local areas, the wall thickness of a vessel shall never be less than that obtained from the formula in NB-3324.1 for cylindrical shells and NB-3324.2 for spherical shells.

NB-3324.1 (Cylindrical Shells):

=

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 31 NB-3324.2 (Spherical Shells):

=

Where:

t = Tentative thickness, in.

P = Design pressure, psi R = Inside radius, in.

Sm = Design stress intensity value, psi A.6.3.1 RVCH The RVCH tentative thickness requirement is the same as the original analysis, contained in the main body of this document.

A.6.3.2 CEDM Nozzle Per Reference A2, the original CEDM nozzle OD is [

] and ID is [

] Using the cylindrical shell formula with P [

] R ( [

] ) and Sm ( [

] ),

the tentative pressure thickness is:

The nozzle wall thickness considering the nominal dimensions is:

[

]

Therefore, the tentative thickness requirement is met.

A.6.4 Reinforcement Requirements The reinforcement requirements are the same as the original analysis, contained in the main body of this document.

A.6.5 Stress and Fatigue Usage Criteria The stress and fatigue usage criteria are the same as the original analysis, contained in the main body of this document.

A.7 Results Summary and Conclusion The repair of CEDM nozzle #46 is acceptable for one cycle of operation.

A.8 References A1.

ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Facility Components, Division I, 1992 with no Addenda A2.

Framatome Drawing 02-9338578-E-002, ANO-2 CEDM Nozzle Pen. #46 IDTB Weld Repair A3.

Framatome Document 08-9338577-001, ANO-2 CEDM Penetration #46 Modification Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 32 APPENDIX B: OVERBORE REPAIR CONTINGENCY B.1 Introduction CEDM penetration #46 at ANO-2 underwent an IDTB weld repair. During the repair weld inclusions were found.

Consequently, addition analysis is necessary. This analysis is for the overbore repair contingency.

B.2 Purpose The purpose of this calculation is to re-evaluate the ASME code requirements per Reference B1 based on the updated overbore contingency dimensions in step 4C per Reference B2.

B.3 Methodology The methodology is the same as the original analysis, contained in the main body of this document. Herein referred to as the original analysis.

B.4 Assumptions The assumptions are the same as the original analysis.

B.5 Design Inputs B.5.1 Geometry Most of the geometry is the same as the original analysis. The geometry that is not the same is listed below.

IDTB Weld OD:

[

]

(Reference B2)

IDTB Weld ID:

[

]

(Reference B2)

B.5.2 Materials The materials are the same as the original analysis.

B.6 Calculations All calculations were completed in excel file overbore_REVISED_OCJ_IDTB Weld_ANO2. This file can be found in Framatome Inc ColdStor system in folder cold/General-Access/32/32-9000000/32-9338944-001.

Note that all dimensions in the following sections will use the worst-case dimension, accounting for tolerances stated on the design drawings, unless otherwise stated. If no tolerance is listed the nominal value is used.

In addition, similar analyses of RVCH IDTB repairs performed for other plants have successfully met all ASME Section III criteria in the required follow-on analysis for the life of repair.

B.6.1 Primary Stress Evaluation The primary stress evaluation uses the same methodology as the original analysis.

B.6.1.1 ASME Code Allowable Stresses All the information in the ASME code allowable stresses section in the original analysis is applicable to this analysis.

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 33 B.6.1.2 Loading All the information in the loading section in the original analysis is applicable to this analysis.

B.6.1.3 Primary Stress Intensities and Pure Shear Calculation The primary stress intensities are calculated in the excel file at the inner radius, mean radius, and outer radius not including corrosion. The pure shear stresses are calculated in the excel file only at the outer radius of the IDTB weld, this calculation includes the effects of corrosion. The corrosion reduces the length of the weld along the head, ultimately reducing the area. All values are listed below including the stress ratio, which is calculated as shown below.

=

Below are the general equations used to calculate the stresses:

Axial stress:

=

+

()

+

Hoop stress:

=

(

+ 1)

Radial stress:

=

(

1)

Shear stresses:

=

+

, = = 0 All the calculated stresses conservatively do not consider the support of the RVCH. The original CEDM nozzle is roll expanded, therefore the IDTB weld and nozzle only see a fraction of the stresses listed in Table B-1, Table B-2, and Table B-3.

Note membrane stresses are typically listed as average values. Being that membrane stresses are listed at all three locations they only need to meet criteria at the mean radius location.

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 34 Table B-1: Primary Stress Intensities at IDTB Weld Service Level Location Membrane

+

Bending (psi)

Stress Ratio Membrane (psi)

Stress Ratio Level A Inside Outside Mean Level B Inside Outside Mean Level C Inside Outside Mean Level D Inside Outside Mean Table B-2: Pure Shear Stresses at IDTB Weld Service Level Location Shear Stress (psi)

Stress Ratio Level A Weld OD Level B Weld OD Level C Weld OD Level D Weld OD Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 35 Table B-3: Primary Stress Intensities at CEDM Nozzle Service Level Location Membrane

+

Bending (psi)

Stress Ratio Membrane (psi)

Stress Ratio Level A Inside Outside Mean Level B Inside Outside Mean Level C Inside Outside Mean Level D Inside Outside Mean Both the IDTB weld and the CEDM nozzle met the primary stress intensity requirements at all locations and all service levels. In addition, the IDTB weld meets the pure shear requirements at all service levels.

B.6.1.4 Triaxial Stress Calculation To meet the requirement, Reference B1 states that the algebraic sum of the three primary stresses shall not exceed 4Sm, expect for service level D.

4= 4(23,300 ) = 93,200 The three primary stresses that bound the IDTB weld and CEDM nozzle are: [

] The algebraic sum of the three primary stresses is [

] Since

[

] the triaxial stress requirement is met.

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 36 B.6.2 Weld Size Requirements This weld needs to satisfy the minimum dimension requirements of FIG. NB-4244(d)-1(c) per Reference B1. FIG.

NB-4244(d)-1(c) is shown in Figure B-1. Reference B2 states the CEDM nozzle has an OD of [

]

and ID of [

] which results in a nominal thickness of [

] With the nominal thickness the weld size requirements can be determined. Table B-4 lists the IDTB weld size requirements and results. Figure B-2 shows how the weld size results are applicable to the requirements of NB-4244(d)-1(c).

Figure B-1: NB-4244(d)-1(c)

Table B-4: IDTB Weld Size Results IDTB Weld Formula Description Design Value Allowable Value Criteria met?

Yes Yes Yes Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 37 Figure B-2: Weld Size Location Nozzle Diametric Clearance (NB-3337.3(a), Reference B1)

For a nozzle OD greater than 4 the maximum diametric clearance of 0.030 per NB-3337.3(a). Per Reference B2 the replacement nozzle OD is [

] and the bore ID is [

] The equation below solves for the nozzle diametric clearance.

[

]

Considering,

[

]

The nozzle diametric requirement is met. In addition, the original nozzle is roll expanded and therefore meets the requirements as well.

B.6.3 Tentative Thickness Calculation Tentative Thickness Calculation (NB-3324.1)

The tentative thickness calculation of the RVCH is determined by the methodology specified in NB-3324 of the ASME boiler and Pressure Vessel Code (Reference B1). As stated in the article, except in local areas, the wall thickness of a vessel shall never be less than that obtained from the formula in NB-3324.1 for cylindrical shells and NB-3324.2 for spherical shells.

NB-3324.1 (Cylindrical Shells):

=

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 38 NB-3324.2 (Spherical Shells):

=

Where:

t = Tentative thickness, in.

P = Design pressure, psi R = Inside radius, in.

Sm = Design stress intensity value, psi B.6.3.1 RVCH The RVCH tentative thickness requirement is the same as the original analysis B.6.3.2 CEDM Nozzle Per Reference B2, the original nozzle OD is [

] and ID is [

] Using the cylindrical shell formula with P ( [

] ), R ( [

] ) and Sm ( [

] ), the tentative pressure thickness is:

The nozzle wall thickness considering the nominal dimensions is:

[

]

Therefore, the tentative thickness requirement is met.

B.6.4 Reinforcement Requirements Reinforcement calculations have been updated to reflect the diameter expansion from the reboring process.

B.6.4.1 Removed Area The removed area calculation is almost identical to the one used in the original analysis. The only change is the maximum penetration diameter including the effects of corrosion and dimensioning tolerances is:

do

[

]

Following the methodology used in Section 6.4.1, using the same parameters the removed area due to opening (Arem) is:

Arem

[

]

B.6.4.2 Limits of Reinforcement Reference B2 establishes the limits of the reinforcement area along and normal to the vessel surface. The limits of reinforcement, measured along the mid surface of the nominal wall thickness, shall meet the following:

A. One hundred percent of the required reinforcement shall be within a distance on each side of the axis of the opening equal to the greater of the following:

a.

NB-3334.1(a)(1), Diameter of finished opening, do [

]

Controlled Document

Document No. 32-9339421-001 PROPRIETARY ANO-2 CEDM IDTB Weld Repair One-Cycle Justification - Non Proprietary Page 39 b.

NB-3334.1(a)(2), Sum of radius of finished opening, thickness of nozzle (conservatively equal to zero) and vessel wall which equals [

]

B. Two thirds of the required reinforcement shall be within a distance on each side of the axis of the opening equal to the greater of the following:

a.

NB-3334.1(b)(1): r+0.5 (Rt)0.5 Where R is the mean radius of head, t is the nominal vessel wall thickness, and r is the radius of the finished opening in the corroded condition:

r+0.5 (Rt)0.5 = [

]

b.

NB-3334.1(b)(2): r+2(t + tn)/3 Where r is the radius of the finished opening in the corroded condition, tn is the nozzle thickness (conservatively equal to zero) and t is the nominal vessel wall thickness:

r+2(t+ tn)/3 = [

]

Furthermore, the ASME code prohibits the same reinforcing material from being applied to more than one opening and requires that one half of the reinforcing material lie on each side of the opening. Therefore, the reinforcement limit is restricted to one-half of the distance between similar adjacent penetrations. Used in the original analysis and applicable to this analysis the shortest distance to another opening from penetration No. 46 is

[

] Accordingly, the limit of reinforcement Lr is [

]

B.6.4.3 Available Reinforcement Area The available reinforcement area calculation is almost identical to the one used in the original analysis. The only change is the maximum penetration diameter including the effects of corrosion and dimensioning tolerances is:

do

[

]

Following the methodology used in Section 6.4.3, using the same parameters the total area of reinforcement (Arein) is:

Arein

[

]

Since the total reinforced area is greater than the total area removed the reinforcement requirements are met.

B.6.5 Stress and Fatigue Usage Criteria The stress and fatigue usage criteria are the same as the original analysis.

B.7 Results Summary and Conclusion The repair of CEDM nozzle #46 is acceptable for one cycle of operation.

B.8 References B1.

ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Facility Components, Division I, 1992 with no Addenda B2.

Framatome Drawing 02-9338578-E-002, ANO-2 CEDM Nozzle Pen. #46 IDTB Weld Repair B3.

Framatome Document 08-9338577-001, ANO-2 CEDM Penetration #46 Modification Controlled Document

4 to 2CAN122103 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair Document Number 51-9339429-001 NON-PROPRIETARY

20004-026 (08/12/2020)

Page 1 of 20, including A-1 through A-5 Framatome Inc.

Engineering Information Record Document No.:

51 9339429 -

001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Controlled Document

20004-026 (08/12/2020)

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 2 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 Name and Title/Discipline Signature P/LP, R/LR, M, A-CRF, A Date Pages/Sections Prepared/Reviewed/

Approved or Comments Will Blankenship Engineer I Materials Engineering P

All Ryan Hosler Engineering Supervisor Materials Engineering M

All Stacy Yoder Engineer III Materials Engineering R

All Ryan Hosler Engineering Supervisor Materials Engineering A

All 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 (printed or typed)

Title (printed or typed)

Signature Date N/A

 



 

 



 

 

 



 

 



Controlled Document

20004-026 (08/12/2020)

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 3 Record of Revision Revision No.

Pages/Sections/

Paragraphs Changed Brief Description / Change Authorization 000 All Original Issue. Proprietary information is marked by bold brackets. The corresponding proprietary document is 51-9338718-000.

001 1.0 6.0 Appendix A added Purpose of revision 001 added.

References updated.

Adds a discussion on the effects of the two contingency repairs shown in drawing (Reference 3). Proprietary information is marked by bold brackets.

The corresponding proprietary document is 51-9338718-001.

Controlled Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 4 Table of Contents Page SIGNATURE BLOCK................................................................................................................................2 RECORD OF REVISION..........................................................................................................................3 LIST OF FIGURES...................................................................................................................................5

1.0 BACKGROUND

AND PURPOSE.................................................................................................6 2.0 ASSUMPTIONS............................................................................................................................9 2.1 Justified Assumptions........................................................................................................9 2.2 Assumptions Requiring Verification.................................................................................10 3.0 EVALUATION.............................................................................................................................10 3.1 Scenario #1: Weld Repair without Surface Remediation................................................10 3.1.1 Determination of a PWSCC Crack Growth Rate..............................................11 3.1.2 PWSCC Evaluation of the Modified CEDM Configuration................................11 3.2 Scenario #2: Weld Repair with Rotary Peening Surface Remediation............................11 3.2.1 Service Life of the Rotary Peening Surface Remediation................................11 4.0 REQUIRED REMEDIATION LENGTH........................................................................................12

5.0 CONCLUSION

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

6.0 REFERENCES

............................................................................................................................14 APPENDIX A :

EFFECT OF SHALLOW CUT AND OVERBORE CONTINGENCIES..................... A-1 Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 5 List of Figures Page Figure 1-1: Current Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 (Reference 3)...........7 Figure 1-2: Modified Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 (Reference 3)........................................................................................................................8 Figure 4-1: Distinction Between Top of Rolled Transition and Effective Length of Roll Expansion (Reference 3).......................................................................................................................13 Figure A-1: Initial Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 after Shallow Cut (Reference 3).............................................................................................................. A-1 Figure A-2: Final Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 after Shallow Cut (Reference 3)..................................................................................................................... A-2 Figure A-3: Final Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 after Overbore (Reference 3)..................................................................................................................... A-4 Controlled Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 6

1.0 BACKGROUND

AND PURPOSE Routine inspection of reactor vessel closure head (RVCH) nozzles has revealed cracking in control rod drive mechanism (CRDM) nozzles in United States (U.S.) commercial pressurized water reactors (PWRs). Some of the cracking has resulted in reactor coolant leaks at the pressure boundary. Evidence of such leaks was observed as boric acid crystal deposits via visual inspection of the RVCH. The cracking mechanism has generally been attributed to primary water stress corrosion cracking (PWSCC).

During the Fall 2021 outage (2R28) ultrasonic examination (UT) and surface dye penetrant testing (PT) revealed the presence of a surface breaking indication on the downhill side of the Control Element Drive Mechanism (CEDM) Penetration No. 46 on the RVCH of Arkansas Nuclear One Unit 2 (ANO-2). Due to the aforementioned conditions, Entergy Nuclear Corporation (Owner) contracted Framatome to repair RVCH penetration nozzle No. 46.

The purpose of this document is to evaluate PWSCC of the remaining American Society of Mechanical Engineers (ASME) SB-166 (Alloy 600) nozzle material affected by the repair after performance of the RVCH penetration nozzle inside diameter temperbead (IDTB) weld repair (with rotary peening surface remediation) at ANO-2 (Reference 1) compared to the PWSCC susceptibility of a non-remediated repair. Conclusions from this evaluation can be used to show the benefit of utilizing the surface remediation technique of rotary peening, but the scope of this document does not include providing justification for inspection relief through the MRP-335 process (Reference 2); however, additional analyses can be performed in the future to justify that this peening process meets the requirements in MRP-335. This evaluation includes the CEDM Nozzle Penetration No. 46 seen in the IDTB weld repair drawing (Reference 3). The current configuration of the ANO-2 CEDM is shown in Figure 1-1. This evaluation considers the RVCH Penetration No. 46 nozzle in the as-repaired condition (no surface remediation) and the rotary peening remediated condition.

The areas adjacent to the IDTB weld and the roll and/or machined surface transition on the inner diameter (ID) of the remaining Alloy 600 nozzle are areas of concern. The rotary peening remediation technique is to be applied above the roll transition or machined ID surface, thereby helping to alleviate the concern for PWSCC at this transition region. Therefore, this evaluation is limited in scope to PWSCC concerns of the remaining Alloy 600 nozzle portion affected by the repair (i.e., adjacent to the IDTB weld and the roll and/or machined surface transition (Reference 3)). Figure 1-2 depicts the CEDM modification after rotary peening remediation is performed.

The purpose of revision 001 is to add Appendix A which considers the effects of two contingency repairs on the PWSCC evaluation.

Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 7 Figure 1-1: Current Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 (Reference 3)

Controlled Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 8 Figure 1-2: Modified Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 (Reference 3)

Controlled Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 9 2.0 ASSUMPTIONS 2.1 Justified Assumptions 1.

Upon completion of the repair, it is unlikely that PWSCC flaws will be present in the portion of the Alloy 600 RVCH penetration nozzle affected by the repair. [

] The assumption that it is unlikely for PWSCC flaws to be present in the remaining Alloy 600 nozzle affected by the repair is justified for the following reasons:

a. [

] factors that have historically caused PWSCC (elevated tensile stress (i) and/or off chemistry conditions (ii)) [

]

i.

For RVCH penetration nozzles, the primary cause of elevated tensile stress is residual stresses from the original J-groove welding process, which only affects the base metal directly adjacent to the weld. [

]

ii.

Off-chemistry conditions have caused PWSCC flaws in RVCH penetration nozzles in relatively low stress locations at one international site where resin ingress caused prolonged periods of high sulfate levels Reference 4). In response, the Nuclear Regulatory Commission (NRC) requested in Generic Letter (GL) 97-01 that all U.S. PWRs report whether any resin intrusions exceeded the EPRI PWR water chemistry guidelines (Reference 5). Entergy responded to GL 97-01 and the NRC was satisfied with their response (Reference 6).

Additionally, because ANO-2 follows the EPRI PWR Primary Water Chemistry Guidelines (Reference 7), in the unlikely event of significant resin intrusion, it would be identified and addressed prior to becoming a concern.

b. [

] As part of the modification process, the whole length of the ID of the remaining Alloy 600 CEDM affected by the modification, i.e., the area to be remediated as seen in Figure 1-2, is required to pass PT after machining (Reference 3). The lack of PT indications is commonly accepted as indicative of a flaw-free surface. While PT has missed reasonably deep cracks in CEDM welds, it is acknowledged that a higher quality inspection surface may help improve the reliability of the PT (Reference 8). [

]

c. [

] After performing the IDTB weld, the ID of the Alloy 600 CEDM will be bored, [

]

Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 10

2. [

]

3. [

]

2.2 Assumptions Requiring Verification There are no assumptions requiring verification.

3.0 EVALUATION In November 2001, the NRC published flaw acceptance criteria for axial flaws in RVCH nozzle pressure boundary material (Reference 10). In the repair configuration for ANO-2 RVCH penetration nozzle, the final pressure boundary is comprised of the remaining Alloy 600 nozzle material and the Alloy 52M IDTB weld material (Reference 1). The maximum allowable flaw depth is 75% of the (original) nozzle wall thickness for pressure boundary material. Therefore, where surface remediation is performed, the life of the repair will be based on the estimated time for a PWSCC flaw to propagate through 75% of the thickness of the original Alloy 600 nozzle, considering no initiation time of the PWSCC flaw in the absence of a compressive stress layer. This 75%

through-wall allowable flaw depth remains the acceptance criterion for axial flaws in the pressure boundary portion of the nozzles as seen in ASME Boiler & Pressure Vessel (B&PV) Code 2007 with 2008a Addenda Section XI IWB-3660 (Reference 11).

Stress corrosion cracking requires three synergistic components to occur: 1) susceptible material, 2) aggressive environment, and 3) a sustained tensile stress. Based on laboratory testing and operating experience, Alloy 600 is susceptible to PWSCC in PWR primary water when sufficient tensile stresses are present (typically due to weld residual stresses) (Reference 12). [

] However, the modification also includes rotary peening surface remediation (Reference 1). Rotary peening surface remediation creates a compressive stress layer which removes the tensile stress component required for the initiation of a PWSCC flaw.

This evaluation will estimate the service life (regarding PWSCC) of the remaining Alloy 600 RVCH penetration nozzle material affected by the modification for the following two scenarios: 1) no surface remediation, and 2) rotary peening surface remediation.

3.1 Scenario #1: Weld Repair without Surface Remediation By not performing any surface remediation process, the remaining Alloy 600 nozzle affected by the repair will be susceptible to PWSCC. Initiation of a PWSCC crack can sometimes take decades, but laboratory testing (Reference 12) and operating experience (Reference 13) also indicates that initiation can occur almost immediately in some cases. To estimate the life of the CEDM nozzle without surface remediation, assuming an immediate initiation of a crack after repair, a crack growth rate will be determined and applied to the modified CEDM configuration.

Controlled Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 11 3.1.1 Determination of a PWSCC Crack Growth Rate 3.1.2 PWSCC Evaluation of the Modified CEDM Configuration 3.2 Scenario #2: Weld Repair with Rotary Peening Surface Remediation 3.2.1 Service Life of the Rotary Peening Surface Remediation Rotary peening is a captive shot technology that was originally developed by 3M Corporation for small and/or hard-to-reach surfaces. This process creates compressive residual stresses on the surface much like traditional shot peening (Reference 15), except that the rotary peening process is more controlled and thus results in a more consistent and uniform compressive stress layer. Surface remediation using rotary peening should inhibit PWSCC initiation based on the principle that PWSCC requires a sustained tensile stress, and the rotary peening process will create a uniform compressive stress layer.

PWSCC initiation is not expected in the compressive stress region induced by the rotary peening process due to the removal of one of the three synergistic components of SCC. [

]

Controlled Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 12 4.0 REQUIRED REMEDIATION LENGTH The purpose of this section is to establish the minimum remediation length needed to ensure all regions with stress > 20 ksi (per Code Case N-729-1]) are remediated (Reference 18).

Controlled Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 13 Figure 4-1: Distinction Between Top of Rolled Transition and Effective Length of Roll Expansion (Reference 3)

5.0 CONCLUSION

An evaluation of PWSCC initiation and growth was performed for the CEDM Nozzle Penetration No. 46 IDTB weld modification process for ANO-2. Conservative assumptions were used for the flaw initiation time and CGR.

The industry adopted, 75% through-wall, flaw acceptance criterion was used. In the absence of the compressive stress layer, the estimated minimum time for a PWSCC flaw to grow to a length of 75% of the as-built wall thickness into the modified configuration wall thickness of the CEDM is 2.7 EFPY. With the added compressive stress layer from rotary peening surface remediation, crack initiation from PWSCC is not expected.

Controlled Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 14

6.0 REFERENCES

1.

[

]

2.

Materials Reliability Program: Topical Report for Primary Water Stress Corrosion Cracking Mitigation by Surface Stress Improvement (MRP-335 Revision 3-A), EPRI, Palo Alto, CA: 2016. 3002009241.

3.

[

]

4.

NRC Information Notice 96-11, Ingress of Demineralizer Resins Increases Potential for Stress Corrosion Cracking of Control Rod Guide Drive Mechanism Penetrations, February 14, 1996.

5.

NRC Generic Letter 97-01, Degradation of Control Rod Drive Mechanism Nozzle and Other Vessel Closure Head Penetrations, April 1, 1997.

6.

Letter from Thomas W. Alexion, NRC, to Mr. Craig G. Anderson, Entergy Operations, Arkansas Nuclear One Unit 2 RE: Generic Letter 97-01, Degradation of Control Rod Drive Mechanism Nozzle and Other Vessel Closure Head Penetrations (TAC No. M98544), March 23, 2000, NRC Accession Number ML003695160.

7.

Electric Power Research Institute (EPRI), Pressurized Water Reactor Primary Water Chemistry Guidelines, Volume 1, Revision 7, 2014. 3002000505.

8.

NRC Report NUREG/CR-6996 (PNNL-18372), Nondestructive and Destructive Examination Studies on Removed-from-Service Control Rod Drive Mechanism Penetrations, July 2009, NRC Accession Number ML092170313 and ML092170314.

9.

[

]

10.

Letter from J. Strosnider, NRC, to A. Marion, NEI, Flaw Evaluation Guidelines, NRC Accession Number ML013250451.

11.

American Society of Mechanical Engineers (ASME) Boiler & Pressure Vessel (B&PV) Code, 2007 with 2008a Addenda, IWB-3660 Evaluation Procedure and Acceptance Criteria for PWR Reactor Vessel Head Penetration Nozzles,Section XI, Division 1, July 1, 2008.

12.

Pichon, C. et al., Phenomenon Analysis of Stress Corrosion Cracking in the Vessel Head Penetrations of French PWRs, Proceedings of the Seventh International Symposium on Environmental Degradation of Materials - Nuclear Power Systems, NACE, 1995.

13.

Alley, D. and Dunn, D., Current NRC Perspectives Concerning Primary Water Stress Corrosion Cracking, Proceedings of the 15th International Symposium on Environmental Degradation, TMS, 2011.

14.

Materials Reliability Program Crack Growth Rates for Evaluation Primary Water Stress Corrosion Cracking (PWSCC) of Thick-Wall Alloy 600 Materials and Alloy 82, 182, and 132 Welds (MRP-420)

Revision 1, EPRI, Palo Alto, CA: 2018. 3002014244.

15.

Materials Reliability Program: An Assessment of the Control Rod Drive Mechanism (CRDM) Alloy 600 Reactor Vessel Head Penetration PWSCC Remedial Techniques (MRP-61), EPRI, Palo Alto, CA: 2003.

1008901.

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Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page 15

16.

[

]

17.

[

]

18.

American Society of Mechanical Engineers (ASME) Boiler & Pressure Vessel (B&PV) Code, Code Case N-729-1, Alternative Examination Requirements for PWR Reactor Vessel Upper Heads with Nozzles Having Pressure-Retaining Partial-Penetration Welds,Section XI, Division 1, March 28, 2006.

19.

[

]

20.

[

]

21.

[

]

22.

[

]

Controlled Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page A-1 APPENDIX A:

EFFECT OF SHALLOW CUT AND OVERBORE CONTINGENCIES A.1 Shallow Cut Contingency

[

] The initial configuration of the CEDM after the shallow cut is machined is shown in Figure A-1, and the final configuration of the CEDM after the shallow cut contingency repair is complete is shown in Figure A-2.

Figure A-1: Initial Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 after Shallow Cut (Reference 3)

Controlled Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page A-2 Figure A-2: Final Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 after Shallow Cut (Reference 3)

A.1.1 Scenario #1: Weld Repair without Surface Remediation after Shallow Cut Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page A-3 A.1.1.1 PWSCC Evaluation of the Shallow Cut Contingency Repair CEDM Configuration A.1.2 Scenario #2: Weld Repair with Rotary Peening Surface Remediation after Shallow Cut A.1.3 Required Remediation Length after Shallow Cut A.2 Overbore Contingency

[

] The final configuration of the CEDM after the overbore contingency repair is complete is shown in Figure A-3.

[

] After performing the IDTB weld, the ID of the Alloy 600 CEDM will be bored, [

]

Controlled Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page A-4 Figure A-3: Final Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 after Overbore (Reference 3)

A.2.1 Scenario #1: Weld Repair without Surface Remediation after Overbore Document

Document No.: 51-9339429-001 PWSCC Evaluation for ANO-2 CEDM Nozzle Penetration No. 46 IDTB Weld Repair - Non Proprietary Page A-5 A.2.1.1 PWSCC Evaluation of the Overbore Contingency Repair CEDM Configuration A.2.2 Scenario #2: Weld Repair with Rotary Peening Surface Remediation after Overbore A.2.3 Required Remediation Length after Overbore A.3 Conclusions For both contingency repairs, the industry adopted 75% through-wall flaw acceptance criterion was used. In the absence of the compressive stress layer, the estimated minimum time for a PWSCC flaw to grow to a length of 75% of the as-built wall thickness into the modified configuration wall thickness of the CEDM is [

] With the added compressive stress layer from rotary peening surface remediation, crack initiation from PWSCC is not expected.

Controlled Document

5 to 2CAN122103 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair Document Number 51-9339414-001 NON-PROPRIETARY

20004-026 (08/12/2020)

Page 1 of 18 Framatome Inc.

Engineering Information Record Document No.:

51 9339414 -

001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Controlled Document

20004-026 (08/12/2020)

Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 2 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 Name and Title/Discipline Signature P/LP, R/LR, M, A-CRF, A Date Pages/Sections Prepared/Reviewed/

Approved or Comments Roluf Andersen Materials Engineering Engineer I P

All Ryan Hosler Materials Engineering Engineering Supervisor R

All Darren Wood Manager Engineering A

All 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 (printed or typed)

Title (printed or typed)

Signature Date Mark Michaels Project Manager

 




 

 

 



 





 



 





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20004-026 (08/12/2020)

Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 3 Record of Revision Revision No.

Pages/Sections/

Paragraphs Changed Brief Description / Change Authorization 000 All Original Issue. Proprietary information is marked by bold brackets. The corresponding proprietary document is 51-9338948-000.

001 As noted Appendix A added; Reference 2 updated.

Proprietary information is marked by bold brackets. The corresponding proprietary document is 51-9338948-001.

Controlled Document

Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 4 Table of Contents Page SIGNATURE BLOCK................................................................................................................................ 2 RECORD OF REVISION.......................................................................................................................... 3 LIST OF FIGURES................................................................................................................................... 5 1.0 PURPOSE..................................................................................................................................... 6

2.0 BACKGROUND

............................................................................................................................ 6 2.1 Known Occurrences of Exposed Carbon/Low Alloy Steel Base Metal.............................. 9 3.0 ASSUMPTIONS..........................................................................................................................10 3.1 Justified Assumptions......................................................................................................10 3.2 Assumptions Requiring Verification.................................................................................10 4.0 EVALUATION.............................................................................................................................11 4.1 Corrosion of Exposed Low Alloy Steel in the Modified Configuration.............................11 4.1.1 General Corrosion of Exposed Base Metal......................................................11 4.1.2 Crevice Corrosion of Exposed Base Metal.......................................................12 4.1.3 Galvanic Corrosion of Exposed Base Metal.....................................................13 4.1.4 Stress Corrosion Cracking of Exposed Base Metal..........................................13 4.1.5 Hydrogen Embrittlement of Exposed Base Metal.............................................14 4.2 Corrosion of Alloy 690 and Alloy 52M.............................................................................14 4.3

[

].............................................................15

5.0 CONCLUSION

............................................................................................................................15

6.0 REFERENCES

............................................................................................................................16 APPENDIX A :

IMPACT OF REPAIR CONTINGENCIES IN REFERENCE 2................................. A-1 Controlled Document

Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 5 List of Figures Page Figure 2-1: Current Configuration of CEDM Nozzle at ANO-2 (Reference 2)..........................................7 Figure 2-2: IDTB CEDM Nozzle Repair Configuration (Reference 2)......................................................8 Controlled Document

Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 6 1.0 PURPOSE This document evaluates potential corrosion concerns arising from the final geometrical configuration of the inside diameter temper bead (IDTB) weld modification of the control element drive mechanism (CEDM) Nozzle 46 at Arkansas Nuclear One Unit 2 (ANO-2) (Reference 1). The evaluations performed herein are applicable for the life of the repair. The materials with potential corrosion concerns evaluated within this document include the exposed low alloy steel (LAS) of the reactor vessel closure head (RVCH) as well as the new materials, which include the Alloy 52M IDTB weld, the Alloy 690 replacement CEDM nozzle, the [

] replacement CEDM nozzle guide, and the Alloy 52M fillet weld joining the replacement nozzle to the replacement guide. In evaluating the potential corrosion concerns, this document will provide an estimate of the total corrosion rate of the exposed LAS at the locations of interest affected by the modification. The only corrosion type that will not be evaluated in this document is PWSCC of the remaining Alloy 600 nozzle, which will be evaluated separately.

Revision 001 The purpose of Revision 001 is to discuss the impact of the repair contingencies in Reference 2. This is discussed in Appendix A.

2.0 BACKGROUND

Starting in 2000, several RVCH nozzles at U.S. pressurized water reactors (PWRs) have reported indications which have been attributed to primary water stress corrosion cracking (PWSCC). During the Fall 2021 outage (2R28), ultrasonic examination (UT) and surface dye penetrant testing (PT) revealed the presence of a surface breaking indication on the downhill side of the CEDM Penetration No. 46 on the RVCH of ANO-2. Due to the aforementioned conditions, Entergy Nuclear Corporation (Owner) contracted Framatome to repair RVCH penetration nozzle #46. The current configuration is shown in Figure 2-1 (Reference 2). Framatome will perform an IDTB weld modification of this nozzle, as shown in Figure 2-2 (Reference 2). The repair involves removal of the existing CEDM nozzle guide, roll expansion and machining of the Alloy 600 nozzle, application of the IDTB weld, rotary peening of the modified surface, and welding of the replacement nozzle guide. The repair configuration will leave portions of the LAS inside the RV head penetrations exposed to the primary reactor coolant. Note that Figure 2-1 and Figure 2-2 are for information only and the design specification and design drawings (References 1 and 2, respectively) are the official records of the design.

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Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 7 Figure 2-1: Current Configuration of CEDM Nozzle at ANO-2 (Reference 2)

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Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 8 Figure 2-2: IDTB CEDM Nozzle Repair Configuration (Reference 2)

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Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 9 2.1 Known Occurrences of Exposed Carbon/Low Alloy Steel Base Metal The primary reactor coolant system (RCS), the pressurizer, reactor vessel, and the steam generator are clad with either a stainless steel or nickel-base alloy to prevent corrosion of the carbon or LAS base metal. Throughout the operating history of U.S. PWRs, there have been many cases where a localized area of the carbon or LAS base metal has been exposed to the primary coolant. Several such instances are listed below:

1960s Yankee-Rowe reactor vessel - Surveillance capsules fell from holder assemblies to the bottom of the vessel, releasing test specimens and other debris, leading to perforations in the cladding.

1990 Three Mile Island Unit 1 steam generator - Several tubes have separated within the tube-sheet area exposing the tube-sheet material to primary coolant. (LER 289-1990-005) 1990 ANO Unit 1 pressurizer - A leak was detected at the pressurizer upper level tap nozzle within the steam space in December 1990. The repair consisted of removing the outer section of the nozzle followed by welding a new section of nozzle to the OD of the pressurizer. (LER 313-1990-021) 1991 Oconee-Unit 1 steam generator - A mis-drilled tube-sheet hole in the upper tube-sheet of one of the steam generators, during plugging operation in 1991, led to exposure of a small area of unclad tube-sheet to primary coolant. (Note: This area of the tube-sheet has since been patched and is no longer exposed to coolant.)

1993 McGuire-Unit 2 reactor vessel - A defect in the vessel cladding was discovered during an inspection in July 1993; the defect is believed to have occurred as a result of a pipe dropped in the vessel during construction (1975).

1993 SONGS-Unit 2 hot leg nozzle - A repair to a hot leg nozzle was completed during the 1993 outage at the SONGS Unit 2. This repair consisted of replacing a section of the existing Alloy 600 nozzle with a new nozzle section fabrication from Alloy 690. A gap approximately [

] wide exists between the two nozzle sections where the carbon steel base metal is exposed to the primary coolant. Verbal communication with SONGS personnel indicated that the hot leg nozzle containing this repair was removed and the exposed carbon steel examined.

1994 Calvert Cliffs-Unit 1 pressurizer - Two leaking heater nozzles in the lower head of the pressurizer were partially removed and the penetrations were plugged in 1994. (LER 317-1994-003) 1997 Oconee-Unit 1 OTSG manway - During the end-of-cycle (EOC) 17 refueling outage, a degraded area was observed in the bore of the 1B once through steam generator (OTSG). Subsequent inspection revealed a

[

] long circumferential damaged area to the cladding surface of the manway opening. The exposure of the base metal was confirmed by etching.

2001 CRDM repairs at Oconee Unit 2, Oconee Unit 3, Crystal River Unit 3, Three Mile Island Unit 1, and Surry Unit 1. (LER 270-2001-002, 287-2001-003, 302-2001-004, 289-2001-002, 280-2001-003) 2002 CRDM repairs at Oconee Unit 1 and Oconee Unit 2. (LER 269-2002-003, 270-2002-002) 2003 CRDM/CEDM repairs at St. Lucie Unit 2 and Millstone Unit 2, half nozzle repairs of STP-1 bottom mounted instrument nozzles, half nozzle repairs of pressurizer instrument nozzles at Crystal River Unit

3. (LER 389-2003-002, 498-2003-003, 302-2003-003) 2005 Half-nozzle modification for the TMI-1 pressurizer vent nozzle.

2013 AREVA IDTB half-nozzle repairs to the Harris CRDM nozzle penetrations. (LER 400-2013-001)

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Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 10 In each of these instances, carbon or LAS base metal was exposed to primary coolant in a localized area. Each plant returned to normal operation with the base metal exposed; in the case of Yankee-Rowe, the vessel operated for roughly 30 years with the base metal exposed. There are no known cases of exposed LAS resulting in reduced functionality of the pressure boundary. The operating experience listed above is expected to be applicable to ANO-2 since all are U.S. PWRs, which generally have similar environments (i.e., water temperature and chemistry).

3.0 ASSUMPTIONS 3.1 Justified Assumptions 1.

The methodology used to calculate the combined corrosion rate in Section 4.1.1.2 is conservative relative to any typical variations in the environmental conditions of the primary coolant that may occur at ANO-2.

This is based on several factors. First, the laboratory test conditions reported in Reference 18 are intended to be representative of typical PWR operation. In addition, three major layers of conservatism are built into the methodology:

While plant startup and shutdown are briefly expected to have differing conditions, this is not expected to be a concern. Per Reference 17, the corrosion rate for these conditions is 0.017 ipy, [

] However, the intermediate conditions (350°F) resulting in the faster rate will only occur for a brief duration. Given all of the conservatisms discussed above, the differing conditions during plant startup and shutdown will remain bound by the conservative combined corrosion rate in Section 4.1.1.2.

3.2 Assumptions Requiring Verification No assumptions requiring verification have been used in this evaluation.

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Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 11 4.0 EVALUATION 4.1 Corrosion of Exposed Low Alloy Steel in the Modified Configuration Several types of corrosion can occur when carbon and LAS base metal are exposed to primary coolant. During operating conditions, the primary coolant is deaerated at high temperatures (343°C [650°F] design temperature (Reference 1) depending on the location within the RCS. During shutdown conditions, the primary coolant temperature approaches 21°C (70°F) and may become aerated and/or stagnant depending on the location within the RCS. The following sections discuss the possible corrosion mechanisms for the exposed LAS base metal at the modified location depicted in Figure 2-2.

4.1.1 General Corrosion of Exposed Base Metal General corrosion is defined as a type of corrosion attack (deterioration) which proceeds more or less uniformly over an exposed surface without appreciable localization (Reference 4). Stainless steels and nickel-based alloys (e.g., wrought Type 304, Type 316, Alloy 600, and Alloy 690 and their equivalent weld metals) are essentially resistant to general corrosion in a PWR environment due to their passive protective surface layer. Carbon and LAS, however, may be susceptible to general corrosion depending on the service environment. The major factors affecting the general corrosion susceptibility of LAS are temperature, fluid velocity, water chemistry, and time.

The general corrosion rates of carbon and LAS in aerated and deaerated conditions are discussed in the subsections below.

4.1.1.1 Oxygen Concentration in the Modified Area

[

] Note that there may be some variations in the water chemistry at the exposed LAS due to crevice conditions that could affect the corrosion rate, but this is addressed in Section 4.1.2 4.1.1.2 General Corrosion Rate Many investigators have reported corrosion rates of carbon and LAS in various environments (References 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16). In several instances, the corrosion rates for carbon and LAS have been observed to be similar in PWR environments; this data is applicable to carbon and LAS materials such as A-302, SA-533, and SA-516 plates (References 7, 9, 10, 14). The ANO-2 RVCH LAS is SA-533 Gr. B, Cl. 1.

The Electric Power Research Institute (EPRI) has published a handbook on boric acid corrosion (Reference 17).

This handbook summarizes the industry field experience with boric acid corrosion incidents, a discussion of boric acid corrosion mechanisms, and a compilation of prior boric acid corrosion testing and results. In one evaluation, ASTM A302 Grade B plate was exposed to primary coolant in aerated and deaerated conditions (Reference 18). It was shown that under deaerated conditions (i.e., during operation), the corrosion rate depended on temperature, fluid velocity, boric acid concentration, and time (Reference 18). The corrosion rate was determined to be 0.0762 Controlled Document

Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 12 millimeters/year (mmy) (0.003 inch/year [ipy]) at the maximum velocity tested (11 m/sec [36 ft/sec]), which is expected to be faster than the maximum flow velocity in the vicinity of the modification. This was the maximum corrosion rate reported. Under static conditions (i.e., stagnant) at 343°C [650°F], a maximum corrosion rate of 0.0229 mmy (0.0009 ipy) was reported. In this same study at shutdown conditions (aerated, at low temperature),

the maximum corrosion rate was determined to be 0.0381 millimeter (0.0015 inch) for a two-month shutdown, or 0.229 mmy (0.009 ipy) (Reference 18).

4.1.1.3 General Corrosion Rate in the HAZ 4.1.1.4 Long Term General Corrosion The initial corrosion rate for the exposed LAS is conservatively estimated to be [

] assuming the conditions described in Section 4.1.1.2. [

] the rate will decrease significantly as corrosion occurs causing the formation of an oxide film. To a lesser degree, the corrosion rate will also decrease over time as corrosion products fill the gap between the nozzle and the bore. The gap between the LAS RVCH and the replacement nozzle, depicted on Figure 2-2, is expected to eventually become packed with iron oxide corrosion products such as Fe3O4 and Fe2O3. The long-term release of Fe corrosion products in the RCS is expected to be negligible.

4.1.2 Crevice Corrosion of Exposed Base Metal The environmental conditions in a crevice can become aggressive with time and can cause accelerated local corrosion. The geometry of the gap between the RVCH and replacement nozzle could create the conditions for crevice corrosion. Experiments were conducted to determine the crevice corrosion rate of LAS. The results indicate that the crevice corrosion rate for both aerated and deaerated conditions is less than the respective general corrosion rate (References 12, 18). Operating experience from PWRs shows that crevice corrosion is not normally a problem in PWR systems with expected low oxygen contents (Reference 14).

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Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 13 Several corrosion studies have examined crevice corrosion in the gaps between [

]

Based on previous experiments, crevice corrosion is not expected to be a concern for this modification [

]

4.1.3 Galvanic Corrosion of Exposed Base Metal Galvanic corrosion may occur when two dissimilar metals in contact are exposed to a conductive solution or coupled together. The three essential components to galvanic corrosion are 1) materials possessing different surface potential, 2) a common electrolyte, and 3) a common electrical path. The larger the potential difference between the metals, the greater the likelihood of galvanic corrosion. Low alloy and carbon steel are more anodic than stainless steels and nickel-base alloys (Reference 22) and could therefore be subject to galvanic attack when coupled and exposed to reactor coolant.

Several corrosion tests were performed to determine the influence of coupling. In one test, carbon steel specimens were coupled and uncoupled to stainless steel and exposed to simulated reactor shutdown conditions. The corrosion rates while coupled and uncoupled were determined to be similar (Reference 17).

Additionally, galvanic corrosion of carbon steel coupled to stainless steel in boric acid solution in the absence of oxygen is about equal to the general corrosion rate (Reference 18).

Austenitic stainless steels, such as Type 304, have approximately the same corrosion potential as nickel-base alloys such as Alloy 690. Therefore, galvanic corrosion studies of LAS and stainless steel give insight into the galvanic corrosion of LAS and nickel-base alloys. Specimens made from 5% chromium steel coupled to Type 304 stainless steel were exposed to aerated water at 260°C (500°F) for 85 days (~2000 hours) with no evidence of galvanic corrosion. In the test above, the corrosion rates were not affected by coupling (Reference 16).

Additionally, results of the NRCs boric acid corrosion test program have shown that the galvanic difference between ASTM A533 Grade B (LAS), Alloy 600, and 308 stainless steel is not significant enough to consider galvanic corrosion as a strong contributor to the overall boric acid corrosion process (Reference 23).

Galvanic corrosion between the exposed LAS and Alloy 600, Alloy 690, or their weld metals is not expected to be a concern for the proposed modification.

4.1.4 Stress Corrosion Cracking of Exposed Base Metal Stress corrosion cracking (SCC) can only occur when the following three conditions are present:

x A susceptible material x

A tensile stress x

An aggressive environment Controlled Document

Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 14 Under normal PWR conditions (deaerated), primary water is not a particularly aggressive environment for LAS unless a departure from normal operating conditions occurs (Reference 24). This service environment (i.e.,

deaerated; and low sulfate and chlorides) does not generally support localized corrosion of LAS; therefore the likelihood of a pit or notch forming which would contribute a stress concentrator or SCC initiation site is negligible. Extensive experience with exposed LAS in PWRs (see Section 2.1 of this document) has not resulted in any reported SCC. Overall, SCC in exposed LAS is not expected to be a concern for the IDTB weld modification.

4.1.5 Hydrogen Embrittlement of Exposed Base Metal Hydrogen embrittlement occurs when a materials properties are degraded due to the presence of hydrogen. This type of damage usually occurs in combination with a stress; residual, applied, or otherwise. Hydrogen embrittlement is typically observed in high pressure hydrogen environments and in deformed metals. Hydrogen embrittlement is characterized by ductility losses and lowering of the fracture toughness (Reference 4). High pressure hydrogen environments are not typical of PWR systems and are defined as an environment with approximately 34 MPa to 69 MPa (5,000-10,000 psi) (Reference 25). Although hydrogen is added to PWR water to scavenge oxygen (see Section 4.1.1.1 of this report), the primary contributor of hydrogen diffusion into the LAS is the corrosion process. Corrosion tests on LAS in deaerated boric acid solutions indicated that the maximum concentration of the hydrogen in the LAS from the corrosion process was less than 2 ppm and did not increase with time (Reference 18). The quantity of hydrogen that may accumulate at locations within the coolant system is not expected to induce hydrogen embrittlement in materials at these locations. Therefore, hydrogen embrittlement is not expected to be a concern for the LAS exposed to primary water.

4.2 Corrosion of Alloy 690 and Alloy 52M Alloy 52M (Alloy 52 modified) is the specified IDTB weld material and fillet weld material for the modification of the nozzle (Reference 1, 2). Information regarding the corrosion of Alloy 690 (the associated base metal to Alloy 52M) and Alloy 52 (the base Alloy 52 not containing some of the alloying elements of Alloy 52M) will also be presented. This will provide a better understanding of the potential corrosion concerns of Alloy 52M. The corrosion resistance of Alloy 52M is expected to be similar to that of Alloy 52 and Alloy 690. The difference between Alloy 52 and 52M is minor alloying elements for enhanced weldability. The chromium content, which provides the corrosion resistance of the material, is similar. The corrosion resistance of Alloy 690 has been extensively studied as a result of numerous PWSCC failures in mill annealed Alloy 600 in primary water environments. As a result of Alloy 600 failures, Alloy 690 has been chosen by the nuclear industry as the replacement material for Alloy 600 components. A comprehensive review for the use of Alloy 690 in PWR systems cites numerous investigations and test results under a wide array of conditions, including both primary (high temperature deoxygenated water) and secondary coolant environments. The first Alloy 690 steam generator went online in May 1989 with no reported failures due to environmental degradation as of the date of that publication (August 1997) (Reference 26). No environmental degradation of Alloy 690 or its related weld metals has been reported since August 1997. More specifically, industry experience has shown that crevice and general corrosion of austenitic nickel-base materials are not expected to be of great concerns in typical PWR conditions (Reference 27).

Alloy 52M was tested (not as a part of this work scope) in accelerated corrosion conditions by testing a weld mockup that simulated nozzle safe end repairs. The testing consisted of 400°C (752°F) steam plus hydrogen doped with 30 ppm each of fluoride, chloride, and sulfate anions. The hydrogen partial pressure was controlled at approximately 75kPa (10 psi) with a total steam pressure of 20 MPa (2.9 ksi); this environment has been previously used to accelerate the simulated PWSCC of nickel-base alloys. After a cumulative exposure of 2051 hours0.0237 days <br />0.57 hours <br />0.00339 weeks <br />7.804055e-4 months <br /> (equivalent to 45.6 EFPY), no environmental degradation was detected on the surface of the Alloy 52M welds. Small micro-fissures on the surface of the Alloy 52M welds, stressed in tension, did not serve as initiation sites for environmental degradation, nor did they propagate during the tests. Stress corrosion cracks initiated in the also-tested Alloy 182 welds in exposure times less than one-fifth the total exposure time of the Controlled Document

Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 15 Alloy 52M specimens (Reference 28). This study, along with many others (examples in References 29, 30, and 31) indicate that the Alloy 52M weld metal in the proposed modification has a high resistance to PWSCC.

SCC test data comparing results between Alloy 690 and Alloy 600 is available in both aerated and deaerated high temperature water. [

] Based on the above studies and the excellent operating experience, Alloy 690 [

]

4.3

[

]

5.0 CONCLUSION

This document evaluates the potential corrosion mechanisms that may affect the final geometrical configuration of the exposed LAS in the proposed ANO-2 RVCH penetration modification configuration, shown in Figure 2-2.

Based on this evaluation, the modification is found acceptable with respect to its effect on corrosion of the affected material (as detailed below).

Galvanic corrosion, hydrogen embrittlement, SCC, and crevice corrosion are not expected to be a concern for the exposed LAS base metal resulting from the IDTB modification process. General corrosion of the exposed LAS base metal will occur. Based on industry data, the general corrosion rate of the LAS due to the nozzle modification is conservatively estimated to be [

]

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Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 16 Extensive operating experience and laboratory testing of Alloy 52 and its associated base metal (Alloy 690) indicate that the Alloy 52M weld metal and Alloy 690 in the modification has a high resistance to PWSCC and is not susceptible to any other forms of degradation in the PWR environment.

[

]

6.0 REFERENCES

References identified with an (*) are maintained within Entergys 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.

U.S. Nuclear Regulatory Commission, NUREG/CR-6923, Expert Panel Report on Proactive Materials Degradation Assessment.

4.

ASM Metals Handbook, Eleventh Edition, Volume 13A Corrosion, 2003.

5.

B. Pastina, et. al., The Influence of Water Chemistry on the Radiolysis of the Primary Coolant Water in Pressurized Water Reactors, Journal of Nuclear Materials, 264 (1999) 309-318.

6.

P. Scott, A Review of Irradiation Assisted Stress Corrosion Cracking, Journal of Nuclear Materials, 211 (1994) 101-122.

7.

Whitman, G. D. et. al., A Review of Current Practice in Design, Analysis, Materials, Fabrication, Inspection, and Test, ORNL-NSIC-21, ORNL, December 1967.

8.

Vreeland, D. C. et. al., Corrosion of Carbon and Low-Alloy Steels in Out-of-Pile Boiling Water Reactor Environment, Corrosion, v17, June 1961, p. 269.

9.

Vreeland, D. C. et. al., Corrosion of Carbon Steel and Other Steels in Simulated Boiling-Water Reactor Environment: Phase II, Corrosion, v18, October 1962, p. 368.

10.

Uhlig, H. H., Corrosion and Corrosion Control, John Wiley & Sons, New York, 1963.

11.

Copson, H. R., Effects of Velocity on Corrosion by Water, Industrial and Engineering Chemistry, v44, No. 8, p. 1745, August 1952.

12.

Vreeland, D. C., Corrosion of Carbon Steel and Low Alloy Steels in Primary Systems of Water-Cooled Nuclear Reactors, Presented at Netherlands-Norwegian Reactor School, Kjeller, Norway, August 1963.

13.

Pearl, W. L. and Wozadlo, G. P., Corrosion of Carbon Steel in Simulated Boiling Water and Superheated Reactor Environments, Corrosion, v21, August 1965, p. 260.

14.

DePaul, E. J., Corrosion and Wear Handbook for Water-Cooled Reactors, McGraw-Hill Book Company, Inc. 1957.

15.

Tackett, D. E. et. al., Review of Carbon Steel Corrosion Data in High-Temperature Water, High-Purity Water in Dynamic Systems, USAEC Report, WAPD-LSR(C)-134, Westinghouse Electric Corporation, October 14, 1955.

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Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 17

16.

Ruther, W. E. and Hart, R. K., Influence of Oxygen on High Temperature Aqueous Corrosion of Iron, Corrosion, v19, April 1963, p. 127.

17.

• Boric Acid Corrosion Guidebook, Revision 2: Managing Boric Acid Corrosion Issues at PWR Power Stations, EPRI, Palo Alto, CA: 2012. 1025145.

18.

Evaluation of Yankee Vessel Cladding Penetrations, Yankee Atomic Electric Company to the U. S.

Atomic Energy Commission, WCAP-2855, License No. DPR-3, Docket No. 50-29, October 15, 1965.

19.

Ferguson, M., Examination of 24-inch Tube Sheet Assembly from the 37-Tube OTSG, LR:68:2218-05:1, Babcock & Wilcox, AREVA NP, Inc. Proprietary, Alliance, Ohio, January 18, 1968.

20.

Emanuelson, R. H., et al., Results of the Operation and Examination of a 19 Tube Model Boiler Damaged to Simulate Crystal River 3-B Steam Generator, LR:81:5267-05:01, Babcock & Wilcox, Alliance, Ohio, October 26, 1981.

21.

MRP-163, Materials Reliability Program: Reactor Vessel head Boric Acid Corrosion Testing (MRP-163) - Task 1: Stagnant and Flow Primary Water Tests, December 2005.

22.

ASM Metals Handbook, Ninth Edition, Volume 13 Corrosion, 1987.

23.

U. S. NRC publication NUREG-1823, U.S. Plant Experience with Alloy 600 Cracking and Boric Acid Corrosion of Light-Water Reactor Pressure Vessel Materials, NRC Accession No. ML051390139.

24.

P.M. Scott and D.R. Tice, Stress Corrosion in Low Alloy Steels, Nuclear Engineering and Design, Volume 119, 1990.

25.

Gray, H.R., Testing for Hydrogen Environment Embrittlement: Experimental Variables, STP543, 1974, ASTM.

26.

Crum, J.R., Nagashima, T., Review of Alloy 690 Steam Generator Studies, Eighth International Symposium on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, August 10-14, 1997, ANS.

27.

Fyfitch, S. (2012) Corrosion and Stress Corrosion Cracking of Ni-Base Alloys. In: Konings R.J.M., (ed.)

Comprehensive Nuclear Materials, volume 5, pp. 69-92, Amsterdam: Elsevier.

28.

Jacko, R.J., et. al., Accelerated Corrosion Testing of Alloy 52M and Alloy 182 Weldments, Eleventh International Conference on Environmental Degradation of Materials in Nuclear System, August 10-14, 2003, ANS.

29.

Sedriks, A.J., et. al., Inconel Alloy 690 - A New Corrosion Resistant Materials, Boshoku Gijutsu, Japan Society of Corrosion Engineering, v28, No. 2, pp. 82-95, 1979.

30.

Brown, C.M., and Mills, W.J., Effect of Water on Mechanical Properties and Stress Corrosion Behavior of Alloy 600, Alloy 690, EN82H Welds, and EN52 Welds, Corrosion, v55(2), February 1999.

31.

Mills, W.J., and Brown, C.M., Fracture Behavior of Nickel-Based Alloys in Water, Ninth International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, August 1-5, 1999, TMS.

32.

MRP 2008-018, MRP White Paper on Stress Corrosion Cracking of Stainless Steel Components in Pressurized Water Reactors Primary Water Environments, December 2007.

33.

[

]

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Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page A-1 APPENDIX A:

IMPACT OF REPAIR CONTINGENCIES IN REFERENCE 2 Several repair contingences have been developed by Framatome in Reference 2. These contingencies will be discussed in the following sections.

A.1 Shallow Cut Contingency

[

] Therefore, this contingency will not have an effect on the conclusions of Revision 000 of this document (see Section 5.0).

A.2 Overbore Contingency

[

] this contingency will not have an effect on the conclusions of Revision 000 of this document (see Section 5.0).

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