NL-24-0261, 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

ML24201A148
Person / Time
Site:	Hatch, Farley, Vogtle
Issue date:	07/19/2024
From:	Coleman J Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
NL-24-0261
Download: ML24201A148 (1)

Text

Regulatory Affairs 3535 Colonnade Parkway Birmingham, AL 35243 205.992.5000

July 19, 2024

Docket Nos.: 50-321 50-348 50-424 52-025 NL-24-0261 50-366 50-364 50-425 52-026

U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001

Edwin I. Hatch Nuclear Plant Units 1 and 2 Joseph M. Farley Nuclear Plant Units 1 and 2 Vogtle Electric Generating Plant Units 1, 2, 3, and 4 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

Ladies and Gentlemen:

Southern Nuclear Operating Company (SNC) is the licensed operator for the Edwin I. Hatch Nuclear Plant (HNP) Units 1 and 2, the Joseph M. Farley Nuclear Plant (FNP) Units 1 and 2, the Vogtle Electric Generating Plant (VEGP) Units 1 and 2, and VEGP Units 3 and 4. The requirements of 10 CFR 50.46(a)(3)(ii) include an annual report by licensees of changes to, or errors in, acceptable emergency core cooli ng system (ECCS) models that affect the temperature calculation and the estimated effect of changes or errors on the limiting ECCS analysis. Accordingly, the reports required by 10 CFR 50.46(a)(3)(ii) for FNP Units 1 and 2 and VEGP Units 1 and 2 ECCS models that affected the temperature calculation are provided in the enclosures to this letter.

For VEGP Units 3 and 4, Westinghouse Letter DCP_NRC_003348 (ADAMS Accession Number ML24086A510) documents general code maintenance changes affecting the ASTRUM (2004)

Realistic Large Break LOCA Evaluation Model that had a 0°F effect on PCT and was determined to be applicable to the plant-specific model. There were no changes to or errors in the NOTRUMP-AP Appendix K Small Break Model. Therefore, for calendar year 2023, no reports are required for VEGP Units 3 and 4.

For calendar year 2023, there were no changes or errors to report for HNP Units 1 and 2; thus, no reports are required for those units.

The resulting peak cladding temperatures (PCT) for HNP Units 1 and 2, FNP Units 1 and 2, and VEGP Units 1, 2, 3, and 4 continue to meet the criterion of 10 CFR 50.46(b)(1) (i.e., 2200°F).

This letter contains no NRC commitments. If you have any questions, please contact Ryan Joyce at 205.992.6468.

U. S. Nuclear Regulatory Commission NL-24-0261 Page 2

Respectfully submitted,

Jamie M. Coleman Regulatory Affairs Director

Enclosures:

1. Joseph M. Farley Nuclear Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

2. Alvin W. Vogtle Electric Generating Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

cc: Regional Administrator, Region ll NRR Project Manager - HNP, FNP, VEGP 1&2, and VEGP 3&4 Senior Resident Inspector - HNP, FNP, VEGP 1&2, and VEGP 3&4 RType: CGA02.001

Edwin I. Hatch Nuclear Plant Units 1 and 2 Joseph M. Farley Nuclear Plant Units 1 and 2 Vogtle Electric Generating Plant Units 1, 2, 3 and 4 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

Enclosure 1 to NL-24-0261

Joseph M. Farley Nuclear Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

to NL-24-0261 Joseph M. Farley Nuclear Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

Joseph M. Farley Nuclear Plant Unit 1 ASTRUM (2004) Best Estimate Large Break LOCA Evaluation

Table 1-1a - Summary of Changes/Errors (2023)

Estimated Description Effect

( PCT F)

Evaluation of 2°F containment temperature increase (Reference 1) 2 Evaluation of containment heat sink coatings (Reference 1) 0 General code maintenance (References 1 and 2) 0

Table 1-1b - Cumulative Impact of Changes/Errors

Description lPCTl (F)

Changes/Errors Previously Reported (References 3 and 4) 21 Summary of Changes/Errors (2023) (References 1 and 2) 2 Cumulative Total 23

Page 1 of 4 to NL-24-0261 Joseph M. Farley Nuclear Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

Joseph M. Farley Nuclear Plant - Unit 1 NOTRUMP Appendix K Small Break LOCA Evaluation

Table 1-1c - Summary of Changes/Errors (2023)

Estimated Description Effect

( PCT F)

Evaluation of 2°F containment temperature increase (Reference 1) 0

Table 1-1d - Cumulative Impact of Changes/Errors

Description lPCTl (F)

Changes/Errors Previously Reported (Reference 5) 0 Summary of Changes/Errors (2023) (Reference 1) 0 Cumulative Total 0

Page 2 of 4 to NL-24-0261 Joseph M. Farley Nuclear Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

Joseph M. Farley Nuclear Plant - Unit 2 ASTRUM (2004) Best Estimate Large Break LOCA Evaluation

Table 1-2a - Summary of Changes/Errors (2023)

Estimated Description Effect

( PCT F)

Evaluation of 2°F containment temperature increase (Reference 1) 2 Evaluation of containment heat sink coatings (Reference 1) 0 General code maintenance (References 1 and 2) 0

Table 1-2b - Cumulative Impact of Changes/Errors

Description lPCTl (F)

Changes/Errors Previously Reported (References 3 and 5) 21 Summary of Changes/Errors (2023) (References 1 and 2) 2 Cumulative Total 23

Page 3 of 4 to NL-24-0261 Joseph M. Farley Nuclear Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

Joseph M. Farley Nuclear Plant - Unit 2 NOTRUMP Appendix K Small Break LOCA Evaluation

Table 1-2c - Summary of Changes/Errors (2023)

Estimated Description Effect

( PCT F)

Evaluation of 2°F containment temperature increase (Reference 1) 0

Table 1-2d - Cumulative Impact of Changes/Errors

Description lPCTl (F)

Changes/Errors Previously Reported (Reference 5) 0 Summary of Changes/Errors (2023) (Reference 1) 0 Cumulative Total 0

References:

1. Westinghouse Letter ALAM-LOCA-TM-A5-000006, J. M. Farley Units 1 and 2, 10 CFR 50.46 Annual Notification and Reporting for 2023, dated February 12, 2024.

2. Westinghouse Letter LTR-NRC-24-6, U.S. Nuclear Regulatory Commission, 10 CFR 50.46 Annual Notification and Reporting for 2023, dated March 14, 2024 (ML24086A508).

3. Letter NL-17-1480 from J. J. Hutto to USNRC, Joseph M. Farley Nuclear Plant Units 1 and 2, 10 CFR 50.46 ECCS Evaluation Model Annual Report Update, dated September 11, 2017 (ML17254A191).

4. Letter NL-20-0630 from Cheryl A. Gayheart to USNRC, Edwin I. Hatch Nuclear Plant Units 1 and 2, Joseph M. Farley Nuclear Plant Units 1 and 2, Vogtle Electric Generating Plant Units 1 and 2, 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2019, dated June 19, 2020 (ML20176A577).

5. Letter NL-19-0650 from Cheryl A. Gayheart to USNRC, Edwin I. Hatch Nuclear Plant Units 1 and 2, Joseph M. Farley Nuclear Plant Units 1 and 2, Vogtle Electric Generating Plant Units 1 and 2, 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2018, dated June 5, 2019 (ML19156A245).

Page 4 of 4 Edwin I. Hatch Nuclear Plant Units 1 and 2 Joseph M. Farley Nuclear Plant Units 1 and 2 Vogtle Electric Generating Plant Units 1, 2, 3 and 4 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

Enclosure 2 to NL-24-0261

Vogtle Electric Generating Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023 to NL-24-0261 Vogtle Electric Generating Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

Vogtle Electric Generating Plant - Unit 1 BASH Appendix K Large Break LOCA Evaluation

Table 1-1a - Summary of Changes/Errors (2023)

Estimated Description Effect

( PCT) (F)

Evaluation of the impact of modifications to the containment heat sink coatings on the large break loss-of-coolant accident (LBLOCA) analysis 2 of record (AOR) for Vogtle Units 1 and 2.

Evaluation of the impact on the large break loss-of-coolant accident (LBLOCA) analysis of record (AOR) of removing the concrete shield ring 0 from containment.

Table 1-1b - Cumulative Impact of Changes/Errors

Description lPCTl (F)

Changes/Errors Previously Reported (Reference 1) 29 Summary of Changes/Errors (2023) (Reference 2) 2 Cumulative Total 31

Page 1 of 4 to NL-24-0261 Vogtle Electric Generating Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

Vogtle Electric Generating Plant - Unit 1 NOTRUMP Appendix K Small Break LOCA Evaluation

Table 1-1c - Summary of Changes/Errors (2023)

Estimated Description Effect

( PCT)

None affecting PCT. 0

Table 1-1d - Cumulative Impact of Changes/Errors

Description lPCTl (F)

Changes/Errors Previously Reported (Reference 1) 0 Changes/Errors 2023 Calendar Year (Reference 2) 0 Cumulative Total 0

Page 2 of 4 to NL-24-0261 Vogtle Electric Generating Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

Vogtle Electric Generating Plant - Unit 2 BASH Appendix K Large Break LOCA Evaluation

Table 1-2a - Summary of Changes/Errors (2023)

Estimated Description Effect

( PCT)

Evaluation of the impact of modifications to the containment heat sink coatings on the large break loss-of-coolant accident (LBLOCA) analysis of 2 record (AOR) for Vogtle Units 1 and 2.

Evaluation of the impact on the large break loss-of-coolant accident (LBLOCA) analysis of record (AOR) of removing the concrete shield ring 0 from containment.

Table 1-2b - Cumulative Impact of Changes/Errors

Description lPCTl (F)

Changes/Errors Previously Reported (Reference 1) 29 Summary of Changes/Errors (2023) (Reference 2) 2 Cumulative Total 31

Page 3 of 4 to NL-24-0261 Vogtle Electric Generating Plant Units 1 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023

Vogtle Electric Generating Plant - Unit 2 NOTRUMP Appendix K Small Break LOCA Evaluation

Table 1-2c - Summary of Changes/Errors (2023)

Estimated Description Effect

( PCT)

None affecting PCT. 0

Table 1-2d - Cumulative Impact of Changes/Errors

Description lPCTl (F)

Changes/Errors Previously Reported (Reference 1) 0 Changes/Errors 2023 Calendar Year (Reference 2) 0 Cumulative Total 0

References:

1. Letter NL-19-0650 from Cheryl A. Gayheart to USNRC, Edwin I. Hatch Nuclear Plant Units 1 and 2, Joseph M. Farley Nuclear Plant Units 1 and 2, Vogtle Electric Generating Plant Units 1 and 2, 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2018, dated June 5, 2019 (ML19156A245)

2. Westinghouse Letter GAEM-LOCA-TM-A5-000004, A. W. Vogtle Units 1 and 2, 10 CFR 50.46 Annual Notification and Reporting for 2023, dated February 13, 2024

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