ML19248C742
| ML19248C742 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 09/25/2019 |
| From: | Peter Bamford Beyond-Design-Basis Management Branch |
| To: | Stoddard D Virginia Electric & Power Co (VEPCO) |
| Peter Bamford 301-415-2833 | |
| References | |
| EPID L-2018-JLD-0003 | |
| Download: ML19248C742 (3) | |
Text
UNITED ST ATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 25, 2019 Mr. Daniel G. Stoddard Senior Vice President and Chief Nuclear Officer Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060
SUBJECT:
NORTH ANNA POWER STATION, UNITS 1 AND 2 -CORRECTION REGARDING STAFF REVIEW OF SEISMIC PROBABILISTIC RISK ASSESSMENT ASSOCIATED WITH REEVALUATED SEISMIC HAZARD IMPLEMENTATION OF THE NEAR-TERM TASK FORCE RECOMMENDATION 2.1: SEISMIC (EPID NO. L-2018-JLD-0003)
Dear Mr. Stoddard:
The purpose of this letter is to provide a correction regarding the staff's evaluation of the North Anna Power Station, Units 1 and 2 (North Anna), seismic probabilistic risk assessment (SPRA) which was submitted in response to Near-Term Task Force (NTTF) Recommendation 2.1 "Seismic." The correction does not change the U.S. Nuclear Regulatory Commission (NRC) staff's previous conclusion that no further response or regulatory action associated with NTTF Recommendation 2.1 "Seismic" is required for North Anna.
By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340}, the NRC issued a request for information under Title 10 of the Code of Federal Regulations Section 50.54(f) (hereafter referred to as the 50.54(f) letter}. The request was issued as part of implementing lessons learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 1 to the 50.54(f) letter requested that licensees reevaluate seismic hazards at their sites using present-day methodologies and guidance. Enclosure 1, Item (8), of the 50.54(f) letter requested that certain licensees complete an SPRA to determine if plant enhancements are warranted due to the change in the reevaluated seismic hazard compared to the site's design-basis seismic hazard.
By letter dated March 28, 2018 (ADAMS Accession No. ML18093A445), Virginia Electric and Power Company (Dominion, the licensee), provided its SPRA submittal in response to, Item (8) of the 50.54(f) letter, for North Anna. The SPRA report was later supplemented by letter dated March 7, 2019 (ADAMS Accession No. ML19071A114). The NRC staff reviewed the SPRA submittal and provided its evaluation by letter dated April 25, 2019 (ADAMS Accession No. ML19052A522). This review used the guidance in NRC staff memorandum dated August 29, 2017, titled, "Guidance for Determination of Appropriate Regulatory Action Based on Seismic Probabilistic Risk Assessment Submittals in Response to Near Term Task Force Recommendation 2.1: Seismic" (ADAMS Accession No. ML17146A200; hereafter referred to as the SPRA Screening Guidance) to develop a recommendation based on its review of the SPRAs submitted by licensees in response to the 50.54(f) letter.
During an internal self-assessment review, the staff recently uncovered an error in the spreadsheet used in the SPRA Screening Guidance to evaluate the North Anna SPRA submittal. The correction of this error results in changes to certain numerical values documented in the staff's North Anna SPRA evaluation dated April 25, 2019. The affected portion of the staffs evaluation is located on page 35 of Enclosure 1, second to last sentence of first paragraph under "Detailed Screening". A description of the original sentence and a corrected version, with changes in bold lettering, is as follows:
Original Version:
The target RRWs based on the mean and 95th percentile SCDF and SLERF were also calculated by the NRC staff and ranged between 1.94 and 1.98 for both units.
Corrected Version:
The target RRWs based on the mean and 95th percentile SCDF and SLERF were also calculated by the NRC staff and ranged between 1.02 and 1.19 for both units.
The staff has confirmed that the changes to the numerical values do not impact or change the NRC decision documented by the previously referenced staff evaluation dated April 25, 2019.
The NRC staff regrets any inconvenience this may have caused. If you have any questions, please contact me at (301) 415-2833 or via e-mail at Peter.Bamford@nrc.gov.
Docket Nos. 50-338 and 50-339 cc: Distribution via Listserv Sincerely, Peter Bamford, Senior roject Manager Beyond-Design-Basis Management Branch Division of Licensing Projects Office of Nuclear Reactor Regulation
- concurrence via email OFFICE NRR/DLP/PBMB/PM NRR/DLP/PBMB/PM NRR/DLP/PBMB/LA NRR/DRA/APLB/TL(A)
NAME PBamford MValentin Slent SVasavada DATE 9/5/19 9/9/19 9/9/19 9/20/19 OFFICE NRR/DLP/PBMB/BC(A) NRR/DLP/PBMB/PM NAME BTitus PBamford nATE 9/24/19 9/25/19