RS-23-094, Relief Request I4R-24, Alternative for Post-Peening Reexamination Frequency for Reactor Pressure Vessel Head Penetration Nozzle Number 75

Relief Request I4R-24, Alternative for Post-Peening Reexamination Frequency for Reactor Pressure Vessel Head Penetration Nozzle Number 75

ML23272A242
Person / Time
Site:	Byron  (NPF-066)
Issue date:	09/29/2023
From:	Lueshen K Constellation Energy Generation
To:	Office of Nuclear Reactor Regulation, Document Control Desk
Shared Package
ML23272A241	List: RS-23-094, Relief Request I4R-24, Alternative for Post-Peening Reexamination Frequency for Reactor Pressure Vessel Head Penetration Nozzle Number 75
References
RS-23-094
Download: ML23272A242 (1)

Text

4300 Winfield Road Warrenville, IL 60555 630 657 2000 Office Proprietary Information - Withhold from Public Disclosure Under 10 CFR 2.390 Attachments 2 and 3 contains Proprietary Information. Withhold from public disclosure under 10 CFR 2.390. When separated from Attachments 2 and 3 this document is decontrolled.

September 29, 2023 10 CFR 50.55a RS-23-094 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Byron Station, Unit 2 Renewed Facility Operating License No. NPF-66 NRC Docket No. STN-50-455

Subject:

Relief Request I4R-24, Alternative for Post-Peening Reexamination Frequency for Reactor Pressure Vessel Head Penetration Nozzle Number 75 In accordance with 10 CFR 50.55a, "Codes and standards," paragraph (z)(2), Constellation Energy Generation (CEG), LLC requests U.S. Nuclear Regulatory Commission (NRC) approval of the attached relief request associated with the fourth inservice inspection interval (ISI) for Byron Station (Byron), Unit 2. Relief is requested to perform the post-peening volumetric examinations of Reactor Pressure Vessel Head Penetration Nozzle (RPVHPN) Number 75 until the next scheduled inspection for the rest of the RPVHPNs at Byron Unit 2. This duration includes the remainder of the current fourth ISI interval and the future fifth ISI interval for Byron Unit 2 until the next scheduled inspections for the RPVHPNs required by 10 CFR 50.55a(g)(6)(ii)(D) are performed.

CEG has identified the performance of this volumetric reexamination on RPVHPN Number 75 every other refueling outage, starting in spring 2025, as a hardship without a compensating increase in the level of quality and safety in accordance with 10 CFR 50.55a(z)(2). The details of the 10 CFR 50.55a request is enclosed.

CEG requests authorization of this request by July 1, 2024. There are no regulatory commitments contained within this letter.

Should you have any questions concerning this letter, please contact Brian Seawright at 779-231-6151.

Respectfully, Kevin Lueshen Sr. Manager Licensing Constellation Energy Generation, LLC Lueshen, Kevin Digitally signed by Lueshen, Kevin Date: 2023.09.29 15:17:40 -05'00'

U.S. Nuclear Regulatory Commission September 29, 2023 Page 2 Attachments 2 and 3 contains Proprietary Information. Withhold from public disclosure under 10 CFR 2.390. When separated from Attachments 2 and 3 this document is decontrolled.

Attachments:

1. 10 CFR 50.55a Relief Request I4R-24 for Byron Station, Revision 0 (Non-Proprietary)

2. Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation (Proprietary)

3. Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis (Proprietary)

4. Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation (Non-Proprietary)

5. Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis (Non-Proprietary)

6. Framatome Affidavit cc:

Regional Administrator - NRC Region III NRC Senior Resident Inspector - Byron Station Illinois Emergency Management Agency - Department of Nuclear Safety

ATTACHMENT 1 Byron Station Unit 2 10 CFR 50.55a Relief Request I4R-24 for Byron Station, Revision 0 Post-Peening Reexamination Frequency for Reactor Pressure Vessel Head Penetration Nozzle Number 75 with Mitigated Alloy 600/82/182 Peened Surfaces (Page 1 of 13)

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 2 of 13)

Request for Relief Post-Peening Reexamination Frequency for Reactor Pressure Vessel Head Penetration Nozzle Number 75 with Mitigated Alloy 600/82/182 Peened Surfaces

1.

ASME Code Components Affected Component Numbers:

Byron Station Unit 2, Reactor Vessel 2RC01R

==

Description:==

Post-Peening Reexamination Frequency for Reactor Pressure Vessel Head Penetration Nozzle (RPVHPN) Number 75 Having Pressure-Retaining Partial-Penetration J-groove Welds with Mitigated Alloy 600/82/182 Peened Surfaces Code Class:

Class 1 Examination Category:

ASME Code Case N-729-6 Code Item:

B4.20 Identification:

RPVHPN Number 75 (P-75)

Reference Drawing:

Closure Head Assembly: 185282E Size:

4 Inch Nominal Outside Diameter, 2.75 Inch Nominal Inside Diameter Material:

SB-167 UNS N06600 (Alloy 600), ENiCrFe-3 (Alloy 182), and ERNiCr-3 (Alloy 82)

2.

Applicable Code Edition and Addenda

Inservice Inspection (ISI) and Repair/Replacement Programs: American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Code,Section XI, 2007 Edition including 2008 Addenda [1]. Examinations of the RPVHPNs are performed in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)(6)(ii)(D), which specifies the use of ASME Code Case N-729-6, with conditions.

Code of Construction [Reactor Pressure Vessel (RPV)]: ASME Section III, 1971 Edition through Summer 1973 Addenda.

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 3 of 13)

3.

Applicable Code Requirement

3.1. General Requirements ASME Code Case N-729-6 contains requirements for the inspection of RPVHPNs, with or without flaws, as conditioned by 10 CFR 50.55a(g)(6)(ii)(D). The specific Code requirements for which use of the proposed alternative is being requested are as follows:

10 CFR 50.55a(g)(6)(ii)(D) requires (in part):

"Holders of operating licenses or combined licenses for pressurized-water reactors as of or after June 3, 2020 shall implement the requirements of ASME BPV Code Case N-729-6 instead of ASME BPV Code Case N-729-4, subject to the conditions specified in paragraphs (g)(6)(ii)(D)(2) through (8) of this section, by no later than one year after June 3, 2020."

ASME Code Case N-729-6, "Alternative Examination Requirements for PWR Reactor Vessel Upper Heads With Nozzles Having Pressure-Retaining Partial-Penetration Welds,Section XI, Division 1" [2], Figure 2, "Examination Volume for Nozzle Base Metal and Examination Area for Weld and Nozzle Base Metal," is applicable to the RPVHPNs. ASME Code Case N-729-6, Paragraph -2410 specifies that the reactor vessel head penetration welds mitigated by a peening mitigation technique shall be examined on a frequency in accordance with Table 1, Items B4.50 and B4.60, of the Code Case (Refer to [2], hereafter known as N-729-6).

10 CFR 50.55a(g)(6)(ii)(D)(5) requires:

"In lieu of inspection requirements of Table 1, Items B4.50 and B4.60, and all other requirements in ASME BPV Code Case N-729-6 pertaining to peening, in order for a RPV upper head with nozzles and associated J-groove welds mitigated by peening to obtain examination relief from the requirements of Table 1 for unmitigated heads, peening must meet the performance criteria, qualification, and examination requirements stated in MRP-335, Revision 3-A, with the exception that a plant-specific alternative request is not required and NRC condition 5.4 of MRP-335, Revision 3-A, does not apply."

MRP-335, Revision 3-A [3], Table 4-3, provides inspection requirements for Alloy 600 RPVHPNs mitigated by peening. In accordance with 10 CFR 50.55a(g)(6)(ii)(D)(5), the NRC condition 5.4 requirement for inspection in the first refueling outage post peening application (N+1), which is reflected in MRP-335, Revision 3-A, Table 4-3, Note (11)(b), is no longer required. Thus, only a follow-up examination in the second refueling outage post peening application (N+2) is required for RPVHPNs that have experienced less than 8 effective degradation years (EDYs), regardless if indications attributed to primary water stress corrosion cracking (PWSCC) have been previously found.

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 4 of 13)

The inspection frequency requirements for Item B4.60 for RPVHPNs mitigated by peening surface stress improvement (SSI) per MRP-335, Revision 3-A, Table 4-3

[3], require a pre-peening baseline inspection, follow-up inspection, and subsequent in-service inspection. The follow up inspections for all 79 nozzles were completed during spring 2022 (B2R23) refueling outage, where a volumetric examination of 100% of the required volume or equivalent surfaces of the nozzle tube and a leak path examination was performed. In the same manner, the volumetric examination of repaired penetrations 6 and 68 was performed during the same refueling outage.

The proposed alternative would not modify the requirement of 10 CFR 50.55a(g)(6)(ii)(D)(5) and MRP-335, Revision 3-A, Table 4-3, Item B4.50 [3] that a bare metal visual examination (VE) of all identified nozzles be performed each refueling outage. Under the proposed alternative, a VE will be performed of all identified nozzles in accordance with 10 CFR 50.55a(g)(6)(ii)(D).

4.

Reason for Request

On April 23, 2022, during the Byron Station, Unit 2, spring 2022 (B2R23) refueling outage, volumetric examinations of the Reactor Vessel Head Core Exit Thermocouple (CETC) Penetration P-75 identified a recordable indication that did not meet the applicable acceptance criteria during the post-peening N+4 follow-up volumetric examinations [26]. This indication was found within the required examination area in accordance with ASME Code Case N-729-6 [2]. No indications were identified on the rest of the RPVHPNs, and the extent of condition was limited to P-75.

The indication at P-75 was found outside the required peening coverage area in accordance with MRP-335, Revision 3-A [3]. Peening had not been performed on this area due to geometry limitations where the guide funnel fillet (tack) welds and the adjacent areas are shadowed by top of the guide funnel. This indication is located at 184 degrees with a length of 0.197" with a depth of 0.141" from the outer diameter (OD) surface of the CETC penetration. The indication extends from 1.498" to 1.695" from the end of the nozzle. The indication is axially oriented and is at the location of one of the guide funnel tack welds. The indication is in the CETC penetration nozzle itself and not in the guide funnel tack weld. Although this portion of the nozzle is not part of the pressure retaining boundary, it does fall within the jurisdiction of ASME Section XI and is Class 1 safety related.

Byron Station, prior to start up, completed an analysis to determine growth of the flaw in accordance with ASME Code Case N-729-6 [2] and ASME Section XI, 2007 Edition through the 2008 Addenda [1]. The immediate analysis documents that the Unit 2 reactor vessel head remains operable for two fuel cycles (until the spring 2025 (B2R25) refueling outage). A figure of the indication details is shown in an NRC submitted report summarizing that analysis [25].

Since 10 CFR 50.55a(g)(6)(ii)(D), ASME Code Case N-729-6 [2], and MRP-335, Revision 3-A [3] are silent on any reexamination requirements for flaws found outside the MRP-335, Revision 3-A [3] required peening area, it is assumed that the entire P-75 is flawed. As such, P-75 has been conservatively identified as Item No. B4.20 (MRP-335, Revision 3-A, Table 4-3 [3] or ASME Code Case N-729-6, Table 1 [2])

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 5 of 13) where the reexamination frequency becomes every other refueling outage until the flaw is repaired and post-repair volumetric examination is performed the following outage. The rest of the RPVHPNs are identified as Item No. B4.60 (MRP-335, Revision 3-A, Table 4-3 [3] or ASME Code Case N-729-6, Table 1 [2]) based on the post-peening volumetric examination results.

As a justification to align the reexamination frequency of P-75 with the rest of the RPVHPNs, a fatigue and PWSCC flaw growth evaluation [28] was performed using finite element analysis (FEA) to revert reexamination requirement of Item No. B4.20

[2][3] for P-75 back to Item No. B4.60 [2][3] like the rest of the RPVHPNs. This will result in a reduction in person-rem exposure and decrease outage complexity.

In summary, performance of a volumetric examination on P-75 every other refueling outage until the flaw is repaired, starting in spring 2025 (B2R25), is considered a hardship without a compensating increase in the level of quality and safety in accordance with 10 CFR 50.55a(z)(2) based on the assessments and supplemental evaluations described below.

5.

Proposed Alternative and Basis for Use 5.1. Proposed Alternative Constellation Energy Generation, LLC (CEG) is requesting relief to perform the post-peening volumetric examinations of P-75 in accordance with Item No. B4.60 [2][3]

once per inspection interval like the rest of the RPVHPNs. The next inspection for the rest of the RPVHPNs (Item No. B4.60) is scheduled to be performed during the fifth ISI interval as required by 10 CFR 50.55a(g)(6)(ii)(D). The proposed alternative is based on fatigue and PWSCC crack growth analyses [28].

Performing this examination every other refueling outage as an Item No. B4.20

[2][3] until the flaw is repaired is a hardship due to person-rem exposure and increased outage complexity. Based on these factors, CEG has identified the performance of this volumetric reexamination as a hardship without a compensating increase in the level of quality and safety in accordance with 10 CFR 50.55a(z)(2).

5.2. Fatigue and PWSCC Flaw Growth Evaluation - P-75 Guide Funnel Tack Weld Flaw A fatigue and PWSCC flaw growth evaluation [28] was performed using finite element analysis (FEA) to establish an acceptable period of operation based on the predicted crack growth and the acceptance criteria defined by ASME Section XI IWB-3663 [1].

Based on PWSCC crack growth rate of ASME Section XI, Article O-3230 [1], the acceptable period of operation is 17.4 effective full power years (EFPY) for the CETC nozzle. Based on PWSCC crack growth rate of MRP-420, Revision 1 [27], the acceptable period of operation is 15.3 EFPY for the CETC nozzle. Additionally, the minimum distance between the top of the final axial flaw length and the bottom of the J-groove weld is 3.7 inches so the flaw will not reach the pressure boundary weld. The guide funnel is not at risk of becoming foreign material prior to the next volumetric examination, as the evaluation [28] demonstrated that it would take 25 EFPY for the flaw to become circumferentially unacceptable.

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 6 of 13)

This demonstrates that the detected PWSCC found outside the peened area will not lead to a safety concern or an unacceptable probability of leakage in the time interval until the next Item No. B4.60 inspection interval. Therefore, this justifies a reexamination frequency of once per inspection interval for P-75 which allows CEG to revert to the examination requirement of Item No. B4.60 per 10 CFR 50.55a(g)(6)(ii)(D) and MRP-335, Revision 3-A [3] like the rest of the RPVHPNs.

The flaw growth evaluation [28] is provided in Attachment 2. Additionally, in support of the flaw growth evaluation, a 3D finite element weld residual and operating stress analysis [29] is provided in Attachment 3.

5.3. Post-Peening Volumetric Examinations at Other Units To date, within CEG, peening of RPVHPNs has been performed at Byron Unit 2 (spring 2016 / fall 2017), Braidwood Unit 1 (fall 2016 / spring 2018), Braidwood Unit 2 (spring 2017), and Byron Unit 1 (spring 2017). The post-peening N+2 follow-up volumetric examination was performed at Byron Unit 1 in spring 2020, with no indications accepted for continued service and no welded repairs required (i.e., no relevant indications) [20], thereby qualifying for the MRP-335, Revision 3-A, Table 4-3, Item No. B4.60 examination frequency of once per inspection interval. The post-peening N+4 follow-up volumetric examinations have been performed for the other units including any repaired penetrations. These examinations were performed in spring 2022 at Byron Unit 2, fall 2022 at Braidwood Unit 1, and spring 2023 at Braidwood Unit 2.

The RPVHPNs at Braidwood Unit 1, Braidwood Unit 2, Byron Unit 1, and Byron Unit 2 were all fabricated by Babcock and Wilcox (B&W) using Alloy 600 material supplied by B&W Tubular Products. The RPVHPNs at all four units were also peened using the Ultra High Pressure Cavitation Peening (UHPCP) process. Thus, the RPVHPNs in all four units have similar histories, with similar head materials, nozzle manufacturers, and peening processes. Hence, the favorable experiences with the post-peening follow-up volumetric examinations at Byron Unit 1 and Braidwood Units 1 and 2 are relevant to the peened head at Byron Unit 2.

6.

Duration of Proposed Alternative The proposed alternative is requested until the next scheduled inspection for Item No. B4.60 at Byron Unit 2 as required by 10 CFR 50.55a(g)(6)(ii)(D).

This duration includes the remainder of the current fourth ISI interval and the fifth ISI interval for Byron Unit 2 until the next scheduled inspections for Item No. B4.60 required by 10 CFR 50.55a(g)(6)(ii)(D) are performed.

7.

Precedent None.

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 7 of 13)

8.

References

1.

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

2.

ASME Code Case N-729-6, "Alternative Examination Requirements for PWR Reactor Vessel Upper Heads With Nozzles Having Pressure-Retaining Partial-Penetration Welds,Section XI, Division 1," Approval Date: March 3, 2016.

3.

Letter from David Czufin (TVA) and Brian Burgos (EPRI) to U.S. Nuclear Regulatory Commission, "Transmittal of 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," dated November 8, 2016. (available at www.epri.com) [NRC ADAMS Accession No. ML16319A282].

4.

Letter from D. Wrona (U.S. Nuclear Regulatory Commission) to B. Hanson (Exelon Generation Company, LLC), "Byron Station, Unit No 2, Relief from the Requirements of the ASME Code (EPID L-2018-LLR-0118)," dated February 25, 2019. Relief Request I4R-16 Regarding Alternative Follow-Up Inspections for Reactor Pressure Vessel Head Penetration Nozzles. [NRC ADAMS Accession No. ML19035A294].

5.

Letter from K. J. Green (U.S. Nuclear Regulatory Commission) to B. Hanson (Exelon Generation Company, LLC), "Byron Station, Unit Nos. 1 and 2 -

Request for Relief from the Requirements of the ASME Code (CAC Nos.

MF8282 and MF8283)," dated March 6, 2017. Relief Request No. I4R-10, Revision 2, Regarding Reactor Vessel Head Penetrations. [NRC ADAMS Accession No. ML17062A428].

6.

Letter from D. M. Gullott (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Response to Request for Additional Information for Byron Station and Braidwood Station Post Peening Relief Requests," dated July 14, 2017, including AREVA Licensing Report ANP 3601NP Revision 0, "Response to Request for Additional Information for Byron Station Unit 2 and Braidwood Station Unit 1," dated July 2017 (Non-Proprietary). [NRC ADAMS Accession No. ML17200C952].

7.

Letter from D. Hoots (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Licensee Event Report (LER) 455-2007-001-00, Reactor Pressure Vessel Head Control Rod Drive Mechanism Penetration Nozzle Weld Indication Due to an Initial Construction Weld Defect Allows the Initiation of Primary Water Stress Corrosion Cracking," dated June 8, 2007.

[NRC ADAMS Accession No. ML071590211].

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 8 of 13)

8.

Letter from F. Kearney (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Licensee Event Report (LER) 455-2014-004-00, Byron Unit 2 Reactor Pressure Vessel Head Control Rod Drive Mechanism Penetration Nozzle Weld Indication Attributed to Primary Water Stress Corrosion Cracking," dated December 5, 2014. [NRC ADAMS Accession No. ML14339A538].

9.

Byron Unit 2, Penetration 68 Inspection Data Sheets:

a. CBE-R13-BP05-68-04, Ultrasonic Report Sheet, dated April 13, 2007.

b. CBE-R13-BP01-68-01, Ultrasonic Report Sheet, dated April 9, 2007.

c. CBE-R13-BP01-68-01, Eddy Current Report Sheet, dated April 9, 2007.

d. Exelon Nuclear Liquid Penetrant Examination Data Sheet, Report Number 2007-276, dated April 10, 2007.

e. CBE-R12-2-068-R1, R2, R3, Ultrasonic Report Sheet, dated April 27, 2007.

f.

CBE-R13-2-068-R1, Eddy Current Report Sheet, dated April 27, 2007.

g. "Review of CRDM inspection Data from Byron Unit 2 Penetration #68,"

dated April 2007. KUW009 R1 Draft B.

h. "Review of CRDM Inspection Data from Byron Unit 2 Penetration #68" dated April 2007. KUW009 R2 Issue 1-0.

i.

Exelon Nuclear Liquid Penetrant Examination Data Sheet, Report Number 2007-315, dated April 23, 2007.

10. Byron Unit 2, Penetration 6 Inspection Data Sheets:

a. CBE-R18-CP02-06-03, 04, 05, Ultrasonic Report Data Sheet, dated October 17, 2014.

b. CBE-R18-CP02-06-01, Ultrasonic Report Data Sheet, dated October 7, 2014.

11. Byron Unit 2 - Technical Basis for Reactor Pressure Vessel Head Inspection Relaxation, AM-2007-011 Revision 1, Exelon Nuclear, September 27, 2007. [NRC ADAMS Accession No. ML091030445].

12. Materials Reliability Program (MRP) Crack Growth Rates for Evaluating Primary Water Stress Corrosion Cracking (PWSCC) of Thick-Wall Alloy 600 Materials (MRP-55) Revision 1, EPRI, Palo Alto, CA: 2002. 1006695.

13. Exelon Engineering Change EC628148 Rev 000, "B2R21 Effective Degradation Years (EDY) Results and Effective Full Power Years Evaluation,"

dated August 7, 2019.

14. G. White, K. Fuhr, M. Burkardt, and C. Harrington, "Deterministic Technical Basis for Re-Examination Interval of Every Second Refueling Outage for PWR Reactor Vessel Heads Operating at Tcold with Previously Detected PWSCC,"

Proceedings of the ASME 2016 Pressure Vessels & Piping Conference, ASME, PVP2016-64032.

15. Technical Note TN-4069-00-02, Revision 1, "Experience for Unmitigated CRDM Nozzles in U.S. PWRs Evaluated for Margin Against Leakage Considering Additional PWSCC Growth if Indications Had Remained in Service," Dominion Engineering, Inc., Reston, VA, July 2020.

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 9 of 13)

16. Letter from H. Berkov (U.S. Nuclear Regulatory Commission) to H. A. Sepp (Westinghouse Electric Company), "Acceptance for Referencing - Topical Report WCAP-15987-P, Revision 2, 'Technical Basis for the Embedded Flaw Process for Repair of Reactor Vessel Head Penetrations,'" dated July 3, 2003.

[NRC ADAMS Accession No. ML031840237].

17. Letter from R. Pascarelli (U.S. Nuclear Regulatory Commission) to T. D. Gatlin (South Carolina Electric & Gas Company), "Virgil C. Summer Nuclear Station, Unit 1 - Alternative Request Weld Repair for Reactor Vessel Upper Head Penetrations (TAC NO. MF3546)," dated April 30, 2014. [NRC ADAMS Accession No. ML14107A332].

18. Materials Reliability Program: Reevaluation of Technical Basis for Inspection of Alloy 600 PWR Reactor Vessel Top Head Nozzles (MRP-395). EPRI, Palo Alto, CA: 2014. 3002003099. [NRC ADAMS Accession No. ML14307B007].

19. Letter from J. A. Hardy (Entergy) to U.S. Nuclear Regulatory Commission, "LER 2018-003 Indications Identified in Reactor Pressure Vessel Head Nozzle Penetrations, Palisades Nuclear Plant," dated January 3, 2019.

[NRC ADAMS Accession No. ML19003A239]

20. Letter from H. Peterson (NRC) to B. C. Hanson (Exelon), "Byron Station -

Integrated Inspection Report 05000454/2020001 and 05000455/2020001,"

dated April 24, 2020. [NRC ADAMS Accession No. ML20115E528].

21. "Generic Guidance for an Effective Boric Acid Inspection Program for Pressurized Water Reactors," WCAP-15988-NP Revision 2, June 2012.

22. Letter from A. J. Vitale (Entergy) to U.S. Nuclear Regulatory Commission, "Licensee Event Report # 2018-001-00, 'Penetration Indications Discovered During Reactor Pressure Vessel Head Inspection,' Indian Point Unit No. 2,"

dated May 21, 2018. [NRC ADAMS Accession No. ML18149A126].

23. "Pressurized Water Reactor Owners Group Standard RCS Leakage Action Levels and Responses Guidelines for Pressurized Water Reactors," WCAP-16465-NP Revision 0, September 2006. [NRC ADAMS Accession No. ML070310082].

24. Letter from H. Welt (Constellation) to U.S. Nuclear Regulatory Commission, LER 2022-001-01 for Byron Station, Unit 2, Volumetric Examinations of Reactor Pressure Vessel Head Core Exit Thermocouple Penetration P-75 Identified an Indication Attributed to Primary Water Stress Corrosion Cracking. [NRC ADAMS Accession No. ML23243A934].

25. Letter from J. J. Kowalski (Constellation) to U.S. Nuclear Regulatory Commission, Report Summarizing the evaluation, including inputs, methodologies, assumptions, extent of conditions, and causes of the new flaw, unacceptable flaw, or flaw growth pursuant of the Topical Report for Primary Water Stress Corrosion Cracking Mitigation by Surface Stress Improvement (MRP-335, Revision 3-A) Report. [NRC ADAMS Accession No. ML22123A219].

26. INR-B2R23-UT-75, RVCH Penetration Ultrasonic Examination, Penetration 75, Reportable Indication Notification Report, dated April 22, 2022.

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 10 of 13)

27. Materials Reliability Program: Crack Growth Rates for Evaluating Primary Water Stress Corrosion Cracking (PWSCC) of Thick-Wall Alloy 600 Materials and Alloy 82, 182, and 132 Welds (MRP-420, Revision 1), EPRI Document Number 3002014244, July 2018.

28. Framatome Document 32-9360155-001, Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation, (Proprietary Version).

Framatome Document 32-9366084-000, Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary, (Non-Proprietary Version).

29. Framatome Document 32-9355610-001, Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis, (Proprietary Version). Framatome Document 32-9366076-000, Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary, (Non-Proprietary Version).

30. Letter from N. L. Delgado (U.S. Nuclear Regulatory Commission) to B. Hanson (Exelon Generation Company, LLC), "Byron Station, Unit No. 2 - Relief from the Requirement of the ASME Code {COVID-19] (EPID L-2020-LLR-0098) dated September 9, 2020. Safety Evaluation by The Office Nuclear Regulation:

Relief Request I4R-17 Regarding Alternative Follow-Up Inspections for Reactor Pressure Vessel Head Penetration Nozzles Exelon Generation Company, LLC Byron Station, Unit No. 2 Docket No. 50-455. [NRC ADAMS Accession No. ML20245E506].

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 11 of 13)

Table 1: Summary of Byron Unit 2 CRDM Nozzle PWSCC Indications Outage Detected Outage Number Pen. #

Nozzle OD/ID Uphill /

Downhill Primary Flaw Orient.

Depth, a (in.)

Depth-to-Thick.,

a/t Length 2c (in.)

Aspect

Ratio, 2c/a Elevation of Upper Tip Above As-Built Weld Toe (in.)

Remaining Vertical Ligament to Leakage (in.)

Spring 2007 B2R13 68 OD Downhill Axial 0.304 47%

0.60 2.0 0.50 1.22 Fall 2014 B2R18 6

OD Downhill Axial 0.222 34%

0.52 2.3 0.60 0.96 NOTE Table 2: Summary of Byron Unit 2 CETC Nozzle Guide Funnel Tack Weld PWSCC Indication Outage Detected Outage Number Pen. #

Nozzle OD/ID Primary Flaw Orient.

Location (deg.)

End Point 1 from End of Nozzle.

(in.)

End Point 2 from End of Nozzle.

(in.)

Length, 2c (in.)

Depth, a (in.)

Depth-to-Thick.,

a/t Distance between Top of Axial Flaw and Bottom of J-Groove Weld, (in.)

Spring 2022 B2R23 75 OD Axial 184 1.498 1.695 0.197 0.141 23%

5.9 NOTE

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 12 of 13)

Table 3: Summary of Byron Unit 2 RPVHPN NDE Since Spring 2007 Outage Season Outage Number Volumetric Examination and Leak Path Assessment per N-729-x Direct Visual Examination (VE) per N-729-x Visual Mode 3 Walkdowns and VT-2 per ASME Section XI Relevant Indications PT of Embedded Flaw Repairs Examination of Previously Repaired Nozzles Spring 2007 B2R13 Performed Performed Performed UT indication, penetration 68 Performed on penetration 68 N/A Fall 2008 B2R14 Performed Performed Performed UT, PT of penetration 68 Spring 2010 B2R15 Performed on penetration 68 only Performed Performed UT, PT of penetration 68 Fall 2011 B2R16 Performed Performed Performed UT, PT of penetration 68 Spring 2013 B2R17 Performed on penetration 68 only Performed Performed UT, PT of penetration 68 Fall 2014 B2R18 Performed Performed Performed UT indication, penetration 6 Performed on penetration 6 UT, PT of penetration 68 Spring 2016 B2R19 Performed Performed Performed UT of penetrations 6 and 68 PT of penetration 6 Fall 2017 B2R20 Performed on 9 nozzles being re-peened Performed Performed UT of penetration 68 PT of penetrations 6 and 68 Spring 2019 B2R21 Performed Performed Fall 2020 B2R22 Deferral to B2R23 Performed Performed PT of penetration 6 and 68 scheduled Spring 2022 B2R23 Performed Performed Performed UT indication, penetration 75 guide funnel tack weld (outside of required peened area)

UT of penetrations 6 and 68 Note:

Direct visual examinations were also performed in B2R10 (Fall 2002) and B2R12 (Fall 2005).

10 CFR 50.55a Relief Request I4R-24 for Byron Station, Unit 2 Revision 0 (Page 13 of 13)

Table 4: Results for PWSCC Growth of Hypothetical 12% Through-Wall Axial Flaws in Byron Unit 2 CRDM Nozzle Nozzle Incidence Angle (°)

Calendar years from a/t = 12% until leak (See Note 2)

ID flaw on uphill side ID flaw on downhill side OD flaw on uphill side OD flaw on downhill side 0.0 9.1 See Note 1 11.0 11.0 25.4 8.6 9.1 13.6 42.8 7.2 9.6 17.5 43.8 7.1 9.6 18.4 47.0 6.9 10.0 20.6 Note 1:

For axially oriented ID flaws on the inside surface of the nozzle, the most rapid growth is predicted on the uphill side of the J-groove weld for a flaw located at the weld. Thus, results for ID flaws on the downhill side are not presented in AM-2007-011 [11].

Note 2:

Results shown conservatively assume a 98% capacity factor.

ATTACHMENT 4 Framatome Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation (Non-Proprietary)

Page 1 of 25 0402-01-F01 (Rev. 021, 03/12/2018)

CALCULATION

SUMMARY

SHEET (CSS)

Document No.

32 9366084 000 Safety Related: Yes No Title Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary PURPOSE AND

SUMMARY

OF RESULTS:

Purpose:

The purpose of this calculation is to evaluate fatigue and primary water stress corrosion crack growth of a postulated semi-elliptical axial flaw and a semi-elliptical circumferential flaw located in the RV head CETC nozzle (penetration

1. 75) OD surface (inboard region of the J-groove weld) at Byron Unit 2 nuclear power plant in order to establish the acceptable period of operation based on ASME Section XI IWB-3663 (Reference [2]) acceptance criteria.

The proprietary version of this document is 32-9360155-001.

Summary of Results:

The results of the flaw growth analysis, performed to establish an acceptable period of operation based on the predicted PWSCC and fatigue crack growth and the acceptance criteria defined by ASME Section XI IWB-3663, Reference [2], show that, based on PWSCC crack growth rate of ASME Section XI, Article O-3230 (Reference [2]),

the acceptable period of operation is [

] effective full power years (EFPY) for the CETC nozzle. Based on PWSCC crack growth rate of MRP-420, Revision 1 (Reference [3]), the acceptable period of operation is [

]

EFPY for the CETC nozzle.

Additionally, the minimum distance between the top of the final axial flaw length and the bottom of the J-groove weld is [

] inches.

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 kweightv3 (Section 5.0)

Document No. 32-9366084-000 0402-01-F01 (Rev. 021, 03/12/2018)

Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - 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 Luziana Matte, Advisory Engineer LP All Pages/All Sections Samer Mahmoud, Advisory Engineer LR All Pages/All Sections Tim Schmitt Unit Manager 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.

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



 













Document No. 32-9366084-000 0402-01-F01 (Rev. 021, 03/12/2018)

Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 3 Record of Revision Revision No.

Pages/Sections/Paragraphs Changed Brief Description / Change Authorization 000 All Original Issue. The proprietary version of this document is 32-9360155-001.

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - 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 INTRODUCTION

/ PURPOSE...................................................................................................... 7 2.0 ANALYTICAL METHODOLOGY................................................................................................... 8 2.1 Postulated Flaws............................................................................................................................... 8 2.2 Stress Intensity Factor (SIF) Solutions............................................................................................ 10 2.3 Crack Growth Mechanisms in Alloy 600......................................................................................... 11 2.3.1 Fatigue Crack Growth Rate............................................................................................................ 11 2.3.2 PWSCC Crack Growth Rate - ASME Section XI Article O-3230................................................... 11 2.3.3 PWSCC Crack Growth Rate - MRP-420 Revision 1...................................................................... 12 2.4 Methodology for Flaw Growth Analysis........................................................................................... 13 2.5 Acceptance Criteria......................................................................................................................... 14 3.0 ASSUMPTIONS.......................................................................................................................... 14 3.1 Unverified Assumptions................................................................................................................... 14 3.2 Justified Assumptions and Modeling Simplifications....................................................................... 14 4.0 DESIGN INPUTS........................................................................................................................ 16 4.1 Geometry......................................................................................................................................... 16 4.2 Applied Stresses............................................................................................................................. 17 4.2.1 Residual plus Transient Stresses................................................................................................... 17 4.2.2 Residual plus Normal Operating Steady State Stresses................................................................ 19 4.2.3 Sustained Stresses due to Deadweight......................................................................................... 19 4.2.4 Sustained Stresses due to Crack Face Pressure........................................................................... 20 5.0 COMPUTER USAGE.................................................................................................................. 21 5.1 Software and Hardware................................................................................................................... 21 5.2 Computer Files................................................................................................................................ 21 6.0 CALCULATIONS......................................................................................................................... 22 6.1 Axial Flaw........................................................................................................................................ 22 6.2 Circumferential Flaw........................................................................................................................ 23

7.0 CONCLUSION

S.......................................................................................................................... 24

8.0 REFERENCES

............................................................................................................................ 25

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 5 List of Tables Page Table 2-1: Relevant Sources of Stress for Fatigue and PWSCC Flaw Growth Analysis....................... 13 Table 3-1: [

]..................................................... 15 Table 4-1: Flaw Propagation Path Geometry......................................................................................... 16 Table 4-2: Operating Transients and Cycles......................................................................................... 18 Table 4-3: Residual + 100% Power Steady State Operating Condition Stress Distributions................. 19 Table 5-1: Computer Files for Revision 000.......................................................................................... 21 Table 6-1: Summary of Crack Growth for Axial Flaws in Alloy 600....................................................... 22 Table 6-2: Summary of Contribution to Crack Depth Growth ('a) for Axial Flaw in Alloy 600............... 22 Table 6-3: Summary of Contribution to Crack Half-Length Growth ('c) for Axial Flaw in Alloy 600............................................................................................................................... 23 Table 6-4: Summary of Crack Growth for Circumferential Flaws in Alloy 600....................................... 23 Table 6-5: Summary of Contribution to Crack Depth Growth ('a) for Circumferential Flaw in Alloy 600............................................................................................................................... 24 Table 6-6: Summary of Contribution to Crack Half-Length Growth ('c) for Circumferential Flaw in Alloy 600............................................................................................................................ 24

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 6 List of Figures Page Figure 1-1: RVCH CETC Nozzle Penetration 75, Indication Details........................................................ 7 Figure 2-1: OD Surface-Connected, Partial Through-Wall, Semi-Elliptical Axial Flaw............................ 9 Figure 2-2: OD Surface-Connected, Partial Through-Wall, Semi-Elliptical Circumferential Flaw.......... 10 Figure 4-1: Flaw Propagation Path Lines............................................................................................... 17 Figure 4-2: Funnel Guide Half-Model Volume....................................................................................... 20

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 7

1.0 INTRODUCTION

/ PURPOSE During the spring 2022 refueling outage at Byron Station Unit 2 (B2R23), the in-service inspection of the Alloy 600 reactor vessel penetration nozzles such as Control Rod Drive Mechanism (CRDM) and Core Exit Thermocouple (CETC) nozzle penetrations has revealed one indication at Penetration 75 which is a CETC nozzle as shown in Figure 1-1 (Indication Notification Report INR-B2R23-UT-75, included in Appendix A of Reference [1]). The indication is axially oriented and is at the location of one of the funnel fillet welds.

Constellation Energy, which operates Byron Station Unit 2, has requested that Framatome evaluate fatigue and PWSCC growth analysis of a postulated semi-elliptical axial flaw and a semi-elliptical circumferential flaw located in the RV head CETC nozzle OD surface (inboard region of the J-groove weld), where the indication was found at Byron Unit 2, in order to establish the acceptable period of operation based on ASME Section XI IWB-3663 (Reference [2]) acceptance criteria.

The purpose of Revision 001 is to add proprietary bracketing. The results and conclusions of the analysis are not affected.

Figure 1-1: RVCH CETC Nozzle Penetration 75, Indication Details

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 8 2.0 ANALYTICAL METHODOLOGY This section presents several aspects of the fracture mechanics analysis that form the basis of the present flaw evaluation.

2.1 Postulated Flaws As shown in the indication report INR-B2R23-UT-75, included in Appendix A of Reference [1], the indication is located at [

] from the OD surface. The indication also extends

[

]

An OD surface-connected, partial through-wall, semi-elliptical axial flaw is postulated on the remaining Alloy 600 nozzle OD surface where the indication was found as shown in Figure 2-1. Similarly, an OD surface-connected, partial through-wall, semi-elliptical circumferential flaw is also postulated as shown in Figure 2-2.

The analyses contained herein address the growth of the postulated flaws by primary water stress corrosion and fatigue crack growth resulting by the application of cyclic transient stress, weld residual stresses, and sustained loads.

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 9 Figure 2-1: OD Surface-Connected, Partial Through-Wall, Semi-Elliptical Axial Flaw

[

]

[

]

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 10 Figure 2-2: OD Surface-Connected, Partial Through-Wall, Semi-Elliptical Circumferential Flaw 2.2 Stress Intensity Factor (SIF) Solutions The weight function method is used for calculating the SIF solution for the analyzed flaws. This is a well-established fracture mechanics methodology which Framatome has implemented in a Microsoft Excel macro (Kweightv3.xla) and that has been used in NRC approved analyses. The technical basis for this implementation is given in Reference [9].

The general expression of the SIF solution recommended in ASME Section XI, Article O-3210, Eq. (2),

Reference [2], uses the influence coefficients and flaw shape factor, which may be determined using the procedure defined in ASME Section XI, Article A-3000. However, ASME Section XI, Article O-3210 permits alternative procedures to be used. The influence SIF solution discussed in Article O-3210, Eq. (2), Reference [2], are provided for a semi-elliptical flaw in a flat plate geometry. The weight function method implemented in Reference [9] uses more appropriate influence coefficients for semi-elliptical flaws in a cylindrical shell. Verification and validation of the software SIF functions developed in Kweightv3.xla, Reference [9], is documented in Section 5.0.

[

]

[

]

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 11 2.3 Crack Growth Mechanisms in Alloy 600 2.3.1 Fatigue Crack Growth Rate Per Article O-3220 of ASME Section XI (Reference [2]), the fatigue crack growth rate (CGR) of Alloy 600 material in PWR environments can be characterized in terms of the range of the applied stress intensity factor, KI. This characterization is of the form:

= ()

Where 'K is the stress intensity factor range in terms of MPam and da/dN is the fatigue crack growth rate in terms of m/cycle.

C = 4.835x10-14 + 1.622x10-16T - 1.490x10-18T2 + 4.355x10-21T3 SR = [1 - 0.82R]-2.2 SENV = 1 + A (C*SR*'Kn)m-1*TR1-m A = 4.4 x 10-7 m = 0.33 n = 4.1 T = metal temperature (at crack location), oC TR = rise time, set at 30 seconds.

2.3.2 PWSCC Crack Growth Rate - ASME Section XI Article O-3230 Per Article O-3230 of ASME Section XI (Reference [2]), the PWSCC CGR equation for Alloy 600 is given by:

=

1

1

()

Where the crack growth rate is in units of m/sec and the stress intensity factor KI is in units of MPam. The other constants are given by:

Qg = thermal activation energy for crack growth = 130 kJ/mole (31.0 kcal/mole)

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 12 R = universal gas constant = 8.314x10í kJ/mole °K (1.103 x10í kcal/mole °R)

Tref = absolute reference temperature used to normalize data = 598.15 °K (1076.67 °R)

T = absolute operating temperature at location of crack in units of Kelvin or Rankine D = crack growth rate coefficient

= 2.67x10í (for KI is in units of MPam and da/dt in m/seconds)

= 3.69x10í (for KI is in units of ksiin and da/dt in in/year)

Kth = crack tip stress intensity factor threshold = 9 MPam (8.19 ksi in)

E = exponent = 1.16 2.3.3 PWSCC Crack Growth Rate - MRP-420 Revision 1 In addition to the PWSCC CGR from Article O-3230 of ASME Section XI, Reference [2], described in Section 2.3.2, the CGR from equation 6-2 of MRP-420, Rev. 1, Reference [3], is also utilized. The Alloy 600 revised disposition equation provided in Section 6.1.2 of Reference [3] was developed from guidance of the full Expert Panel whose approach is documented in Section 2 of Reference [3] and accounts for cold work levels of up to 12%

(Section 7 of Reference [3]).

The PWSCC CGR solution available in ASME Section XI, Article O-3230, Reference [2], is based on Eq. (4) of MRP-55, Revision 1, published in 2002. The CGR from Reference [3] is compared in Figure 6-1 of [3] and shows that the MRP-420 R1 CGR new fit is conservative relative to the MRP-55 curve fit.

The PWSCC crack growth rate equation for Alloy 600 from Reference [3] is given by:

=

1

1

2 2

Where:

D = crack growth constant = 1.19 x 10-13 for da/dt in terms of m/s K = stress intensity factor in terms of MPam T = metal temperature (at crack location) in units of Kelvin (Justified Assumption Item 3.2.2),

Tref = absolute reference temperature used to normalize data = 598.15 K (325oC)

E

= stress intensity factor exponent = 2.0 Q = thermal activation energy for crack growth = 120 kJ/mol R = universal gas constant = 0.008314 kJ/mol-K The values of the dissolved hydrogen term fH2 / fH2ref at various temperature and hydrogen concentration [H2]

combinations for Alloy 600 are provided in Table 6-1 of Reference [3]. Values at intermediate temperatures and/or hydrogen concentrations are linearly interpolated.

For Byron Unit 2, the [

] hydrogen concentration [H2] of [

] is conservatively selected for analysis per Reference [4], which yields a dissolved hydrogen term fH2 / fH2ref equal to [

]

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 13 2.4 Methodology for Flaw Growth Analysis For the flaw growth analysis, the applied stress intensity factors of the postulated axial and circumferential flaws are driven by hoop and axial stresses, respectively. The relevant sources of stresses for fatigue and PWSCC crack growth are summarized in Table 2-1 and further described in Section 4.2 of this document.

Table 2-1: Relevant Sources of Stress for Fatigue and PWSCC Flaw Growth Analysis

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 14 2.5 Acceptance Criteria The objective of the flaw growth analysis is to establish an acceptable period of operation based on the predicted crack growth and the acceptance criteria defined by ASME Section XI, Reference [2]. Per ASME Section XI Table IWB-3663-1, the service life for a postulated axial flaw located on the inboard of the J-groove weld (nozzle OD) is determined when the postulated axial flaw grows through 100% of the wall thickness. For a postulated circumferential flaw located on the inboard of the J-groove weld (nozzle OD), the service life is determined when the postulated circumferential flaw grows through 100% of the wall thickness or reaches a final flaw length equal to 75% of the nozzle circumferential arc length.

Since the identified flaw is in the vicinity of the funnel guide fillet weld attaching the funnel guide to the CETC nozzle, the acceptance criteria discussed above applies. In addition, the minimum distance between the top of the final axial flaw length and the bottom of the J-groove weld is estimated and reported in this document. This distance does not impact the acceptance criteria of the identified flaw that is established based on ASME Section XI Table IWB-3663-1. However, this distance is reported for information only to demonstrate that the flaw would not reach the pressure boundary weld.

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

3.2 Justified Assumptions and Modeling Simplifications

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 15 Table 3-1: [

]

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 16 4.0 DESIGN INPUTS 4.1 Geometry Crack growth analysis is performed along two path lines in the Alloy 600 nozzle [

]

located at [

] and shown in Figure 4-1. Per Section 6.3.1 of Reference [5], the as-found indication is [

]

The basic dimensions for the selected path lines are taken from Reference [5]. Table 4-1 lists the selected flaw propagation path geometry employed for the flaw growth analysis.

Table 4-1: Flaw Propagation Path Geometry

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 17 Figure 4-1: Flaw Propagation Path Lines 4.2 Applied Stresses The categories of applied stresses that need to be considered are discussed in this section.

4.2.1 Residual plus Transient Stresses The combined cyclic operating stresses and weld residual stresses that are needed to calculate fatigue crack growth are obtained from the analysis performed in Reference [5] along the path lines of interest through the CETC nozzle shown in Figure 4-1.

These cyclic stresses are developed for multiple transients at a number of time points to capture the maximum and minimum stresses due to fluctuations in pressure and temperature. According to Reference [7], the number of cycles of the RVCH design transients is established for 40 years of design life. The list of applicable transients and number of cycles are listed in Table 4-2.

Predictions of fatigue crack growth are evaluated for either the acceptable period of operation defined in Section 2.5 or 25 years of plant operation which corresponds to the time remaining to the end of Bryon Unit 2 license period scheduled for November 2043 from the release of the indication report INR-B2R23 (Appendix A of [1]) dated April 2022. The transient stresses, temperatures, and pressures for path lines [

] are extracted from the output files generated in Reference [5].

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 18 Table 4-2: Operating Transients and Cycles

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 19 4.2.2 Residual plus Normal Operating Steady State Stresses For PWSCC crack growth calculations, residual plus steady state normal operating steady state conditions hoop and axial stresses are evaluated in Reference [5]. The axial and hoop residual stresses at the steady state normal operating condition on path lines [

] are extracted from Table A-3 and Table A-4 in Reference

[5] and listed in Table 4-3 below.

Table 4-3: Residual + 100% Power Steady State Operating Condition Stress Distributions 4.2.3 Sustained Stresses due to Deadweight The sustained deadweight axial stress due to the funnel guide and nozzle length deadweight below the flaw indication is applied to the crack face of the postulated circumferential flaw.

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 20 A conservative deadweight axial stress of [

] is selected in this analysis. [

]

Figure 4-2: Funnel Guide Half-Model Volume 4.2.4 Sustained Stresses due to Crack Face Pressure For the fatigue and PWSCC crack growth analyses, it is conservatively assumed that primary water gets into the flaw and the crack faces are subjected to additional pressure load. [

] Transient pressures as a function of time are obtained from Reference [5]. For PWSCC crack growth analysis, the normal operating pressure load of [

]

Reference [5], is applied to the crack faces.

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 21 5.0 COMPUTER USAGE 5.1 Software and Hardware The Framatome software verification process for this calculation includes the execution of test cases that exercise features of the software which are applicable to the actual analysis done in the calculation. These test cases and the actual analysis are done using the same version of the computer program Kweightv3.xla, Reference [9], executed on the same hardware and operating system. The documentation of the verification process includes identification of the hardware and operating system, the applicable software version, and the results of the test cases, demonstrating that the correct results are achieved.

To validate the use of the SIF functions developed in Kweightv3.xla, Reference [9], Test Cases A1, A2, and B1 provided in Reference [9] are executed. Test cases A1 and A2 are consistency tests to verify the routines interpolating from non-dimensional stress intensity factors tables, and test case B1 is an accuracy test to verify the results against open-source literature. The installation of the software on a PC workstation is documented below and verification tests of similar applications are listed as follows.

Computer program tested: Kweightv3.xla Computer hardware used: [

]

Name of person running the tests: L. Matte Date of tests: 02/02/2023 Acceptability: Results agree with those documented for the corresponding test cases in Reference [9]. Test case runs are documented in the Table 5-1.

5.2 Computer Files The computer files pertinent to revision 000 of this document are listed in Table 5-1 and located in the following ColdStor directory: [

]

Table 5-1: Computer Files for Revision 000

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 22 6.0 CALCULATIONS For every postulated flaw type, a crack growth analysis is conducted to establish the acceptable period of operation based on the predicted crack growth. The final flaw depth is determined by either reaching 25 years of operation from the indication observation date in April 2022 to the end of Bryon Unit 2 license period scheduled for November 2043 or by reaching the allowable final flaw configurations established by the flaw acceptance criteria outlined in Section 2.5.

The following subsections provide the fatigue and PWSCC crack growth analyses for the postulated axial and circumferential flaws.

6.1 Axial Flaw A summary of the fatigue plus PWSCC flaw growth in the Alloy 600 CETC nozzle material for the postulated axial flaw is summarized in Table 6-1 for all path lines. Results are shown with the PWSCC crack growth rates from ASME Section XI, Article O-3230 described in Section 2.3.2 and from MRP-420, Revision 1 described in Section 2.3.3. Contributions of the transient fatigue and PWSCC growths to the final crack depth and length are given in Table 6-2 and Table 6-3.

Table 6-1: Summary of Crack Growth for Axial Flaws in Alloy 600 Table 6-2: Summary of Contribution to Crack Depth Growth ('a) for Axial Flaw in Alloy 600

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 23 Table 6-3: Summary of Contribution to Crack Half-Length Growth ('c) for Axial Flaw in Alloy 600 6.2 Circumferential Flaw A summary of the fatigue plus PWSCC flaw growth in the Alloy 600 CETC nozzle material for the postulated circumferential flaw is summarized in Table 6-4 for all path lines. Results are shown with the PWSCC crack growth rates from ASME Section XI, Article O-3230 described in Section 2.3.2 and from MRP-420, Revision 1 described in Section 2.3.3. Contributions of the transient fatigue and PWSCC growths to the final crack depth and length are given in Table 6-5 and Table 6-6.

Table 6-4: Summary of Crack Growth for Circumferential Flaws in Alloy 600

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 24 Table 6-5: Summary of Contribution to Crack Depth Growth ('a) for Circumferential Flaw in Alloy 600 Table 6-6: Summary of Contribution to Crack Half-Length Growth ('c) for Circumferential Flaw in Alloy 600

7.0 CONCLUSION

S The results of the flaw growth analysis, performed to establish an acceptable period of operation based on the predicted crack growth and the acceptance criteria defined by ASME Section XI IWB-3663, Reference [2], show that, based on PWSCC crack growth rate of ASME Section XI, Article O-3230 (Reference [2]), the acceptable period of operation is [

] effective full power years (EFPY) for the CETC nozzle. Based on PWSCC crack growth rate of MRP-420, Revision 1 (Reference [3]), the acceptable period of operation is [

] EFPY for the CETC nozzle.

Additionally, the minimum distance between the top of the final axial flaw length and the bottom of the J-groove weld is [

] inches.

Document No. 32-9366084-000 Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation - Non-Proprietary Page 25

8.0 REFERENCES

1.

Framatome Document [

]

2.

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

3.

Materials Reliability Program: Crack Growth Rates for Evaluating Primary Water Stress Corrosion Cracking (PWSCC) of Thick-Wall Alloy 600 Materials and Alloy 82, 182, and 132 Welds (MRP-420, Revision 1), EPRI Document Number 3002014244, July 2018.

4.

Framatome Document [

]

5.

Framatome Document [

]

6.

Framatome Document [

]

7.

Redacted Byron/Braidwood Nuclear Stations, Revision 16 to Updated Final Safety Analysis Report, Chapter 3, Design of Structures, Components, Equipment, and Systems. (1438 page(s), 12/15/2016),

ADAMS Accession # ML17086A600

8.

Framatome Document [

]

9.

Framatome Trade Secret Document [

]

ATTACHMENT 5 Framatome Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis (Non-Proprietary)

Page 1 of 70 0402-01-F01 (Rev. 021, 03/12/2018)

CALCULATION

SUMMARY

SHEET (CSS)

Document No.

32 9366076 000 Safety Related: Yes No Title Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary PURPOSE AND

SUMMARY

OF RESULTS:

Purpose:

The purpose of this document is to perform a [

] finite element weld residual stress (WRS) and operating stress analyses of the Byron Unit 2 reactor vessel closure head (RVCH) penetration No. 75 core exit thermocouple (CETC) nozzle J-groove weld and guide funnel attachment welds in support of a subsequent flaw evaluation.

The proprietary version of this document is 32-9355610-001.

Summary of Results:

The state of stress after welding and key operating transients, as predicted by the results from the ANSYS finite element analysis, are summarized in Section 7.0 to support a subsequent flaw evaluation analysis.

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 ANSYS v 19.2 (See Section 5.1)

Document No. 32-9366076-000 0402-01-F01 (Rev. 021, 03/12/2018)

Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - 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 Luziana Matte Advisory Engineer LP All Samer Mahmoud Advisory Engineer LR All Tim Schmitt Unit Manager 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)

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Document No. 32-9366076-000 0402-01-F01 (Rev. 021, 03/12/2018)

Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 3 Record of Revision Revision No.

Pages/Sections/Paragraphs Changed Brief Description / Change Authorization 000 All Initial Release. The proprietary version of this document is 32-9355610-001.

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 4 Table of Contents Page SIGNATURE BLOCK................................................................................................................................ 2 RECORD OF REVISION.......................................................................................................................... 3 LIST OF TABLES..................................................................................................................................... 6 LIST OF FIGURES................................................................................................................................... 8

1.0 INTRODUCTION

AND PURPOSE................................................................................................ 9 2.0 ANALYTICAL METHODOLOGY................................................................................................... 9 3.0 ASSUMPTIONS.......................................................................................................................... 11 3.1 Unverified Assumptions................................................................................................................... 11 3.2 Justified Assumptions and Modeling Simplifications....................................................................... 11 4.0 DESIGN INPUT........................................................................................................................... 14 4.1 Geometry......................................................................................................................................... 14 4.2 Materials.......................................................................................................................................... 15 4.3 Loading Conditions.......................................................................................................................... 16 4.3.1 Static Load Conditions...................................................................................................... 16 4.3.2 Operating Transient Conditions........................................................................................ 16 4.3.3 Welding Parameters......................................................................................................... 23 4.3.4 Post Weld Heat Treatment............................................................................................... 24 5.0 COMPUTER USAGE.................................................................................................................. 24 5.1 Software and Hardware................................................................................................................... 24 5.2 Computer Files................................................................................................................................ 25 6.0 FINITE ELEMENT ANALYSIS.................................................................................................... 30 6.1 Finite Element Model....................................................................................................................... 30 6.1.1 Welding Simulation........................................................................................................... 34 6.1.2 Static and Transient Condition Evaluation........................................................................ 37 6.2 Finite Element Analysis Run........................................................................................................... 38 6.3 Finite Element Model Post-Processing........................................................................................... 41 6.3.1 Weld Residual Stresses at Cold and 100% Power Steady State Conditions...................41 6.3.2 Transient Operating plus Residual Stresses.................................................................... 43 7.0

SUMMARY

OF RESULTS.......................................................................................................... 43 7.1.1 Weld Residual Stresses at Cold and 100% Power Steady State Conditions................... 43 7.1.2 Transient Operating plus Residual Stress Results........................................................... 48

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Table of Contents (continued)

Page Page 5

8.0 REFERENCES

............................................................................................................................ 49 APPENDIX A : STRESS TABLES FOR FRACTURE MECHANICS ANALYSIS.................................... 50 APPENDIX B : TEMPERATURES AND GRADIENTS FROM TRANSIENT THERMAL ANALYSIS.................................................................................................................... 54

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 6 List of Tables Page Table 4-1: CETC Nozzle Penetration Key Dimensions.......................................................................... 15 Table 4-2: Component Material Designations........................................................................................ 16 Table 4-3: Static Loads: Pressure and Temperature Values................................................................. 16 Table 4-4: Operating Transients............................................................................................................ 17 Table 4-5: Transient [

].................................................................................................................... 18 Table 4-6: Transient [

].................................................................................................................... 18 Table 4-7: Transient [

].................................................................................................................... 18 Table 4-8: Transient [

].................................................................................................................... 19 Table 4-9: Transient [

]................................................................................................................... 19 Table 4-10: Transient [

]................................................................................................................ 19 Table 4-11: Transient [

].............................................................................................................. 20 Table 4-12: Transient [

]................................................................................................................ 20 Table 4-13: Transient [

]................................................................................................................ 20 Table 4-14: Transient [

].................................................................................................................. 21 Table 4-15: Transient [

]................................................................................................................ 21 Table 4-16: Transient [

].............................................................................................................. 21 Table 4-17: Transient [

]................................................................................................................. 22 Table 4-18: Transient [

]............................................................................................................... 22 Table 4-19: Transient [

].................................................................................................................. 22 Table 4-20: Transient [

].............................................................................................................. 23 Table 4-21: Heat Transfer Coefficients................................................................................................... 23 Table 4-22: Welding Parameters........................................................................................................... 24 Table 4-23: Post-Weld Heat Treatment Temperature............................................................................ 24 Table 5-1: Computer Files..................................................................................................................... 25 Table 6-1: Finite Element Analysis Run Sequence................................................................................ 38 Table 6-2: Time Points in Stress Analysis - Normal/Test Transients.................................................... 40 Table 6-3: Time Points in Stress Analysis - Upset Transients.............................................................. 40 Table A-1: Residual Stress Distributions at Cold Shutdown Condition - [

]........................ 50 Table A-2: Residual Stress Distributions at Cold Shutdown Condition - [

].................... 51 Table A-3: Residual + 100% Power Steady State Operating Condition Stress Distributions -

[

]......................................................................................................................... 52

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary List of Tables (continued)

Page Page 7 Table A-4: Residual + 100% Power Steady State Operating Condition Stress Distributions -

[

].................................................................................................................... 53

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 8 List of Figures Page Figure 4-1: RVCH CETC Nozzle Geometry........................................................................................... 14 Figure 6-1: Finite Element Model........................................................................................................... 31 Figure 6-2: Weld Passes for [

]................................................................................................... 32 Figure 6-3: Weld Passes for [

].................................................................................... 33 Figure 6-4: Weld Passes for [

].......................................................................................... 34 Figure 6-5: Boundary Condition Surfaces.............................................................................................. 37 Figure 6-6: Node Pairs for Evaluation of Temperature Gradient........................................................... 39 Figure 6-7: Stress Path Lines................................................................................................................ 42 Figure 7-1: Residual Stress Contours at Cold Conditions..................................................................... 44 Figure 7-2: Residual Stress Contours at Operating Conditions............................................................. 45 Figure 7-3: Residual Hoop Stress (SY) at Cold Conditions................................................................... 46 Figure 7-4: Residual Axial Stress (SZ) at Cold Conditions.................................................................... 46 Figure 7-5: Residual plus 100% Power Steady State Hoop Stress (SY)............................................... 47 Figure 7-6: Residual plus 100% Power Steady State Axial Stress (SZ)................................................ 47

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 9

1.0 INTRODUCTION

AND PURPOSE During the spring 2022 refueling outage at Byron Station Unit 2 (B2R23), the in-service inspection of the Alloy 600 reactor vessel penetration nozzles such as Control Rod Drive Mechanism (CRDM) and Core Exit Thermocouple (CETC) nozzle penetrations has revealed one indication at Penetration 75, which is a CETC nozzle (Indication Notification Report INR-B2R23-UT-75, included in Appendix A of Reference [1]). The indication is axially oriented and is at the location of one of the guide funnel fillet welds.

The purpose of this analysis is to perform a [

] finite element weld residual stress (WRS) plus operating stress analysis of the Byron Unit 2 Reactor Vessel Closure Head (RVCH) CETC nozzle penetration 75 J-groove weld and guide funnel fillet welds. [

] The state of stress after welding and sufficient cycles between shutdown and normal operating pressure/temperature to achieve shakedown of stresses, as well as stresses due to key operating transients, as predicted by the results of the ANSYS finite element analysis (Reference [2]), are summarized in this report to support a subsequent flaw evaluation analysis.

The purpose of Revision 001 is to add proprietary bracketing and to incorporate document amendment (DA) 159-9363976-000. The results and conclusions of the analysis are not affected.

2.0 ANALYTICAL METHODOLOGY The methodology is based on the methods described in the WRS analysis technical basis document (Reference [3]) and it complies with the general recommendations of industry WRS modeling guidance documents such as MRP-317 (Reference [4]). The fabrication stages of the welding processes are simulated using a [

] finite element model (FEM). The general purpose finite element code ANSYS (Reference [2]) is used to perform the WRS FEA, with the basic steps as follows:

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Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 11 3.0 ASSUMPTIONS 3.1 Unverified Assumptions There are no unverified assumptions used in this analysis 3.2 Justified Assumptions and Modeling Simplifications The following justified assumptions and modeling simplifications are used in this analysis:

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Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 14 4.0 DESIGN INPUT 4.1 Geometry The Byron Unit 2 CETC nozzle penetration, welds and RVCH geometries are illustrated in Figure 4-1 [

] Key dimensions used in the FEM are obtained from References [5], [6], and [7] and listed in Table 5-1. Details of the J-Groove weld and nozzle are obtained from References [8] and [9].

Figure 4-1: RVCH CETC Nozzle Geometry

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 15 Table 4-1: CETC Nozzle Penetration Key Dimensions 4.2 Materials The material designations for the FEA components are listed in Table 4-2. [

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 16 Table 4-2: Component Material Designations 4.3 Loading Conditions 4.3.1 Static Load Conditions The static loading conditions for the evaluation described in Section 2.0, Steps 7 and 8, are listed in Table 4-3 and are obtained from Reference [14].

Table 4-3: Static Loads: Pressure and Temperature Values 4.3.2 Operating Transient Conditions The applicable operating transient conditions for the evaluation described in Section 2.0, [

] are listed in Table 4-4 and are obtained from the original Stress Report documented in Reference [14] and from Table 3.9-1 of the UFSAR, Reference [15]. Temperature and pressure data for each transient are obtained from Figures 1 through 9 of Reference [14] as shown in Table 4-5 through Table 4-20. [

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 17 Table 4-4: Operating Transients

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]

Table 4-6: Transient [

]

Table 4-7: Transient [

]

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]

Table 4-9: Transient [

]

Table 4-10: Transient [

]

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]

Table 4-12: Transient [

]

Table 4-13: Transient [

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 21 Table 4-14: Transient [

]

Table 4-15: Transient [

]

Table 4-16: Transient [

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 22 Table 4-17: Transient [

]

Table 4-18: Transient [

]

Table 4-19: Transient [

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 23 Table 4-20: Transient [

]

4.3.2.1 Heat Transfer Coefficients The heat transfer coefficient values used in the evaluation of the operating transient thermal analysis are listed in Table 4-21.

Table 4-21: Heat Transfer Coefficients 4.3.3 Welding Parameters Reference [16] provides a set of welding assumptions that are used in this document to establish welding parameters for the [

] welds. The welding parameters used for modeling the welding processes of the

[

] welds for the evaluation described in Section 2.0, [

] are provided in Table 4-22.

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 24 Table 4-22: Welding Parameters 4.3.4 Post Weld Heat Treatment The post-weld heat treatment temperature for the evaluation described in 2.0, [

] is given in Table 4-23.

Table 4-23: Post-Weld Heat Treatment Temperature 5.0 COMPUTER USAGE 5.1 Software and Hardware ANSYS Version 19.2 (Reference [2]) is used to solve the following physical problems in this calculation: thermal conduction and nonlinear elastic-plastic structural. The results of the calculations confirm that the thermal and structural responses of the models developed are within the range of applicability for these types of physical problems. Use of this version of ANSYS is acceptable since error notices were reviewed and none was found applicable to this analysis.

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 25 5.2 Computer Files The computer files used in this analysis are listed in Table 5-1. All files are located in ColdStor folder:

[

] The files listed in Table 5-1 are maintained and retrievable from the Framatome quality records system.

Table 5-1: Computer Files

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 26

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 27

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Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 30 6.0 FINITE ELEMENT ANALYSIS 6.1 Finite Element Model The finite element model is a [

] The finite element mesh consists of [

]

The thermal and structural finite element models are generated using the ANSYS Workbench generated input file Generate_Models.inp (Table 5-1). The finite element model is shown in Figure 6-1.

[

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 31 Figure 6-1: Finite Element Model

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 32 Figure 6-2: Weld Passes for [

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 33 Figure 6-3: Weld Passes for [

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 34 Figure 6-4: Weld Passes for [

]

6.1.1 Welding Simulation 6.1.1.1 Thermal Boundary Conditions

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 35 6.1.1.2 Structural Boundary Conditions

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 36

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 37 Figure 6-5: Boundary Condition Surfaces 6.1.1.3 Post Weld Heat Treatment

[

]

6.1.2 Static and Transient Condition Evaluation The surfaces for boundary condition application are shown in Figure 6-5.

6.1.2.1 Thermal Boundary Conditions The following thermal boundary conditions are applied to the model for transient thermal FEA:

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 38 6.1.2.2 Structural Boundary Conditions The following structural boundary conditions are applied to the model for static and transient structural FEAs:

6.2 Finite Element Analysis Run The FEA run sequence described in Section 2.0 is listed in Table 6-1.

Table 6-1: Finite Element Analysis Run Sequence

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[

] Thermal gradient and temperature plots are shown in Appendix B. Time points for the structural transient runs are listed in Table 6-2 and Table 6-3. [

] The thermal gradient listings can be found in the output files *_Ts.txt (Table 5-1). The

• represents the abbreviation for the specific transient of interest (See Table 4-4).

Figure 6-6: Node Pairs for Evaluation of Temperature Gradient

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 40 Table 6-2: Time Points in Stress Analysis - Normal/Test Transients Table 6-3: Time Points in Stress Analysis - Upset Transients

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 41 6.3 Finite Element Model Post-Processing 6.3.1 Weld Residual Stresses at Cold and 100% Power Steady State Conditions Per Appendix A of Reference [1] and page D-27 of Reference [7], the as-found indication is located at [

]

Therefore, path lines are defined in the nozzle as shown in Figure 6-7 [

]

[

]

Stresses are extracted along these paths in a local cylindrical coordinate system with the X-axis radial, Z-axis axial (aligned with the nozzle axis) and Y-axis hoop, as documented in the output computer files WRS_SD.out and WRS_OP.out (Table 5-1). The hoop (SY) and axial (SZ) stresses are extracted [

] along the paths for cold shutdown conditions [

] and steady state operating conditions at 100% power

[

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 42 Figure 6-7: Stress Path Lines

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 43 6.3.2 Transient Operating plus Residual Stresses Stresses due to residual plus transient operating conditions are extracted along the path lines described in Section 6.3.1.

Stresses are listed in a local cylindrical coordinate system with the X-axis radial, Y-axis hoop, and Z-axis axial along the nozzle. The hoop (SY) and axial (SZ) stresses along with temperatures (TH) are listed [

]

along the paths for all analyzed transient time points.

Computer files are listed in Table 5-1. Output files follow the naming convention of *_fr_SY/SZ/TH.out where the

• represents the transient abbreviation per Table 4-4.

7.0

SUMMARY

OF RESULTS 7.1.1 Weld Residual Stresses at Cold and 100% Power Steady State Conditions

[

] The hoop and axial stress contours for the model are shown in Figure 7-1 for cold shutdown conditions and in Figure 7-2 for the 100% power steady state conditions.

The axial and hoop stress profiles are extracted along the path lines through the thickness in the CETC Nozzle shown in Figure 6-7. Charts showing the through wall distribution of residual axial (SZ) and hoop (SY) stresses at cold conditions and 100% power steady state conditions are presented in Figure 7-3 through Figure 7-6. In addition, the hoop and axial through wall stress distributions are also tabulated in Appendix A to be used in subsequent flaw evaluation.

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 44 Figure 7-1: Residual Stress Contours at Cold Conditions

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 45 Figure 7-2: Residual Stress Contours at Operating Conditions

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 46 Figure 7-3: Residual Hoop Stress (SY) at Cold Conditions Figure 7-4: Residual Axial Stress (SZ) at Cold Conditions

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 47 Figure 7-5: Residual plus 100% Power Steady State Hoop Stress (SY)

Figure 7-6: Residual plus 100% Power Steady State Axial Stress (SZ)

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 48 7.1.2 Transient Operating plus Residual Stress Results Stresses due to residual plus transient operating conditions are extracted along the path lines described in Section 6.3.1.

The hoop (SY) and axial (SZ) stresses along with temperatures (TH) are documented in computer files listed in Table 5-1. Output files follow the naming convention of *_fr_SY/SZ/TH.out where the

• represents the transient abbreviation per Table 4-4.

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8.0 REFERENCES

1.

Framatome Document [

]

2.

ANSYS Computer Code, Version 19.2, ANSYS Inc., Canonsburg, PA.

3.

Framatome Document [

]

4.

Materials Reliability Program: Welding Residual Stress Dissimilar Metal Butt-Weld Finite Element Modeling Handbook (MRP-317, Revision 1). EPRI, Palo Alto, CA: 2015. 3002005499.

5.

Framatome Drawing [

]

6.

Framatome Drawing [

]

7.

Framatome Document [

]

8.

Framatome Drawing [

]

9.

Framatome Drawing [

]

10.

Framatome Document [

]

11.

Framatome Document [

]

12.

Byron/Braidwood Nuclear Stations, Revision 16 to Updated Final Safety Analysis Report, Chapter 5, Reactor Coolant System and Connected Systems. (261 page(s), 12/15/2016), ADAMS Accession #

ML16357A521.

13.

Framatome Document [

]

14.

Framatome Document [

]

15.

Byron/Braidwood Nuclear Stations, Revision 16 to Updated Final Safety Analysis Report, Chapter 3, Design of Structures, Components, Equipment, and Systems. (1438 page(s), 12/15/2016), ADAMS Accession # ML17086A600

16.

Framatome Document [

]

17.

Framatome Document [

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 50 APPENDIX A: STRESS TABLES FOR FRACTURE MECHANICS ANALYSIS Table A-1: Residual Stress Distributions at Cold Shutdown Condition - [

]

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]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 52 Table A-3: Residual + 100% Power Steady State Operating Condition Stress Distributions - [

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 53 Table A-4: Residual + 100% Power Steady State Operating Condition Stress Distributions - [

]

Document No. 32-9366076-000 Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis - Non-Proprietary Page 54 APPENDIX B: TEMPERATURES AND GRADIENTS FROM TRANSIENT THERMAL ANALYSIS The following temperatures and temperature gradients between points of interest are used to determine critical time points for thermal stresses. The temperature distribution at the critical time points is used as an input to the structural analysis along with the pressure at that time. Plots in this Appendix are produced from data contained within the nodal temperature thermal output files named *_Ts.txt (Table 5-1). The

• represents the abbreviation for the specific transient of interest. See Section 6.2 for additional discussion.

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]

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]

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]

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]

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]

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]

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ATTACHMENT 6 Framatome Affidavit

A F F I D A V I T

1.

My name is Morris Byram. I am Manager, Licensing & Regulatory Affairs for Framatome Inc. (Framatome) 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 documents numbered 32-9355610-001 and 32-9360155-001 and entitled Byron Unit 2 RVCH CETC Nozzle Penetration No. 75 Weld Residual and Operating Stress Analysis, and Byron Unit 2 RVCH CETC Nozzle PWSCC and Fatigue Flaw Growth Evaluation, respectively, and referred to herein as Documents. Information contained in these Documents has been classified by Framatome as proprietary in accordance with the policies established by Framatome for the control and protection of proprietary and confidential information.

4.

These Documents contain information of a proprietary and confidential nature and is of the type customarily held in confidence by Framatome and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in these Documents as proprietary and confidential.

5.

These Documents have been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in these Documents be withheld from public disclosure. The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure

is requested qualifies under 10 CFR 2.390(a)(4) Trade secrets and commercial or financial information.

6.

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

(a)

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

(b)

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

(c)

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

(d)

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

(e)

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

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

7.

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

8.

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

9.

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

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

Executed on: (8/09/2023)

(NAME) morris.byram@framatome.com BYRAM Morris Digitally signed by BYRAM Morris Date: 2023.08.09 15:53:51 -07'00'