NL-21-0606, 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2020

10 CFR 50.46 ECCS Evaluation Model Annual Report for 2020

ML21182A369
Person / Time
Site:	Hatch, Vogtle, Farley
Issue date:	07/01/2021
From:	Coleman J Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-21-0606
Download: ML21182A369 (4)

Text

Regulatory Affairs 3535 Colonnade Parkway Birmingham, AL 35243 205.992.6611 tel July 1, 2021 Docket Nos.: 50-321 50-348 50-424 NL-21-0606 50-366 50-364 50-425 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 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2020 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, and the Vogtle Electric Generating Plant (VEGP) Units 1 and 2. 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 cooling system (ECCS) models that affect the temperature calculation and the estimated effect of changes or errors on the limiting ECCS analysis.

Accordingly, the report required by 10 CFR 50.46(a)(3)(ii) for HNP Unit 1 is provided in the enclosure to this letter.

There were no changes or errors to report for 2020 for the HNP Unit 2, FNP Units 1 and 2, and VEGP Units 1 and 2 ECCS models that affected PCT; 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 and 2 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 Jamie Coleman at 205.992.6611.

Respectfully submitted, Jamie M. Coleman Licensing Manager JMC/tle

U. S. Nuclear Regulatory Commission NL-21-0606 Page 2

Enclosure:

Edwin I. Hatch Nuclear Plant Unit 1 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2020 cc: Regional Administrator, Region ll NRR Project Manager - HNP, FNP, VEGP 1 & 2 Senior Resident Inspector - HNP, FNP, VEGP 1 & 2 NRR Project Manager - HNP, FNP, VEGP 1 & 2 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 and 2 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2020 Enclosure Edwin I. Hatch Nuclear Plant Unit 1 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2020

Enclosure to NL-21-0606 Edwin I. Hatch Nuclear Plant Unit 1 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2020 Edwin I. Hatch Nuclear Plant Unit 1 Table 1-1a - TRACG-LOCA Summary of Changes / Errors (2020)1 (GNF2, GNF3)

Estimated Description Effect

( PCT, °F)

TRACG radiation heat transfer calculation2 (Reference 1) +35 Table 1-1b - TRACG-LOCA Cumulative Impact of Changes / Errors1 GNF2 GNF3 (LUAs)

Description lPCTl lPCTl

(°F) (°F)

Changes/Errors Affecting PCT Previously Reported 0 0 (See Notes)

Summary of Changes/Errors Affecting PCT (2020) 35 35 (References 1 and 2)

Cumulative Total 35 35 Notes:

1. HNP Unit 1 Cycle 29, which ended in February 2020, was the final use of the SAFER/PRIME-LOCA methodology for HNP Unit 1. There were no errors affecting PCT to report for SAFER/PRIME-LOCA. HNP Unit 1 Cycle 30, which started in March 2020, is the first use of TRACG-LOCA methodology for HNP Unit 1. TRACG-LOCA was already in use for HNP Unit 2 starting in March 2019 (Reference 2).

2. The TRACG radiation heat transfer calculation error is applicable to TRACG-LOCA. It was previously reported for HNP Unit 2 in Reference 2. There were no changes to report for 2020 for HNP Unit 2 regarding the TRACG-LOCA methodology in addition to those previously reported in Reference 1.

References:

1. GE Hitachi 10 CFR 50.46 Notification Letter 2019-02, dated March 21, 2019

2. Letter from Cheryl A. Gayheart to USNRC (NL-20-0630), ML20176A577, 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 E-1