ML24094A140

Staff Response to Request for Revision to NRC Staff Assessment of Updated Seismic Hazard Information and Latest Understanding of Seismic Hazards at the Vogtle Plant Site Following the NRC Process for the Ongoing Assessment of Natural Hazard

ML24094A140
Person / Time
Site:	Vogtle
Issue date:	05/16/2024
From:	John Lamb Plant Licensing Branch II
To:	Coleman J Southern Nuclear Operating Co
References
Download: ML24094A140 (3)

Text

May 16, 2024

Jamie M. Coleman Regulatory Affairs Director Southern Nuclear Operating Co., Inc.

3535 Colonnade Parkway Birmingham, AL 35243

SUBJECT:

STAFF RESPONSE TO REQUEST FOR REVISION TO NRC STAFF ASSESSMENT OF UPDATED SEISMIC HAZARD INFORMATION AND LATEST UNDERSTANDING OF SEISMIC HAZARDS AT THE VOGTLE PLANT SITE FOLLOWING THE NRC PROCESS FOR THE ONGOING ASSESSMENT OF NATURAL HAZARDS INFORMATION

Dear Jamie Coleman:

By letter dated March 28, 2024 (Agencywide Documents and Access Management System (ADAMS) Accession No. ML24088A317), Southern Nuclear Operating Company (SNC, the licensee) requests that the U.S. Nuclear Regulatory Commission (NRC) revise the Vogtle Electric Generating Plant (Vogtle), Units 1, 2, and 3 seismic hazards process for the ongoing assessment of natural hazards information (POANHI) letter to remove a paragraph from the NRC letter dated May 15, 2023 ( ML23006A091), to be consistent with letters issued to other utilities on this subject matter. The paragraph that SNC is requesting to be removed is the following:

The NRC staff notes that Southern Nuclear Operating Company is responsible for considering the impact of this updated hazard on its plant-specific licensing basis including, approved risk informed applications, and, if applicable, the approved program for maintaining the plant-specific seismic probabilistic risk assessment supporting such applications.

In its letter dated May 15, 2023, the NRC staff documented its latest understanding of seismic hazards at the Vogtle, Units 1, 2, and 3, following POANHI. The NRC staff assessment considered new seismic ground motion attenuation models for central and eastern North America and updated seismic site response methods. The POANHI framework was intended to use the minimum res ources necessary to consider new information in a timely manner that is not overly burdensome to licensees.

Based on its evaluation of updated seismic hazard curves for the Vogtle plant site, using the new ground motion models and updated site response methods, the NRC staff determined that no further regulatory evaluation of the Vogtle, Units 1, 2, and 3, plant seismic risk was warranted by the NRC.

J. Coleman

Subsequent plants, such as North Anna and H.B. Robinson, were issued similar letters without the paragraph cited above. The original intent of the subject paragraph was to provide a reminder for licensees to manage/maintain their licensing bases. However, based on stakeholder feedback after issuance of the Vogtle letter, the NRC staff removed the paragraph from subsequent letters to avoid confusion about it s intent. For clarification, the NRC staff was and is not imposing or implying any additional actions or requirements on the licensee beyond those already in its licensing basis. Licensees have existing procedures and practices for evaluating new information and taking corrective action, as appropriate.

The conclusion in the NRC staffs letter dated May 15, 2023, continues to remain valid.

Specifically, based on its evaluation of updated seismic hazard curves for the Vogtle plant site, using the new ground motion models and updated site response methods, the NRC staff determined that no further NRC regulatory action or evaluation of the Vogtle, Units 1, 2, and 3, plant seismic risk is warranted at this time.

If you have any questions, please contact me at (301) 415-3100 or via email at John.Lamb@nrc.gov.

Sincerely,

/RA/

John G. Lamb, Senior Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Docket Nos. 50-424, 50-425, and 52-25

cc: Listserv

ML24094A140 NRR-106 OFFICE NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1/LA NRR/DRA/APLC/BC NAME JLamb KGoldstein SVasavada DATE 04/01/2024 04/03/2024 05/13/2024 OFFICE NRR/DORL/LPL2-1/BC NRR/DORL/D NRR/DORL/LPL2-1/PM NAME MMarkley JPelton JLamb DATE 05/13/2024 05/15/2024 05/16/2024