CNL-22-070, Status Regarding the Improved Flood Mitigation System Project
| ML22181A343 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar, Sequoyah  |
| Issue date: | 06/30/2022 |
| From: | Rymer S Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CNL-22-070 | |
| Download: ML22181A343 (3) | |
Text
Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 CNL-22-070 June 30, 2022 10 CFR 50.4 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Sequoyah Nuclear Plant, Units 1 and 2 Renewed Facility Operating License Nos. DPR-77 and DPR-79 NRC Docket Nos. 50-327 and 50-328 Watts Bar Nuclear Plant, Units 1 and 2 Facility Operating License Nos. NPF-90 and NPF-96 NRC Docket Nos. 50-390 and 50-391
Subject:
STATUS REGARDING THE IMPROVED FLOOD MITIGATION SYSTEM PROJECT
References:
- 1. TVA Letter to NRC, Status Regarding the Improved Flood Mitigation System Project, dated September 30, 2020 (ML20274A368)
- 2. TVA Letter to NRC, Application to Revise Sequoyah Nuclear Plant Units 1 and 2 Updated Final Safety Analysis Report Regarding Changes to Hydrologic Analysis, (TS-19-02), dated January 14, 2020 (ML20016A396)
- 3. TVA Letter to NRC, Supplement to Application to Revise Sequoyah Nuclear Plant Units 1 and 2 Updated Final Safety Analysis Report Regarding Changes to Hydrologic Analysis, (TS-19-02)
(EPID L-2020-LLA-0004), dated February 18, 2020 (ML20049H184)
- 4. NRC letter to TVA, Summary of October 13, 2020, Closed Meeting with Tennessee Valley Authority to Discuss Responses to Requests for Additional Information Regarding Updated Final Safety Analysis Report Hydrologic Analysis License Amendment Request (EPID L-2020-LLA-0004), dated October 27, 2020 (ML20293A080).
By letter dated September 30, 2020, Tennessee Valley Authority (TVA) informed the Nuclear Regulatory Commission (NRC) of a change in the specified field implementation completion schedule to install improved flood mode mitigation systems (FMMS) at the Sequoyah Nuclear Plant (SQN), Units 1 and 2, and the Watts Bar Nuclear Plant (WBN),
Units 1 and 2 (Reference 1). The change in the implementation schedule was based on the ongoing TVA project to upgrade precipitation models and rerun hydraulic models to determine new probable maximum flood levels for both design basis and beyond-design-basis purposes.
U.S. Nuclear Regulatory Commission CNL-22-070 Page 2 June 30, 2022 A license amendment request (LAR) to incorporate an updated hydrologic analysis in the licensing basis for SQN was submitted by letter dated January 14, 2020 (Reference 2) and supplemented by letter dated February 18, 2020 (Reference 3). A similar LAR is being developed for WBN.
Delays in submitting the WBN LAR are associated with the resolution of the Apalachia Dam issue previously discussed with NRC. Following submittal of the SQN LAR to NRC, TVA determined that there was an unverified assumption in calculations concerning the Apalachia Dam failure analysis and entered this issue into the TVA Corrective Action Program. TVA communicated this information to the NRC during a closed public meeting on October 13, 2020 (Reference 4).
Consequently, as described in Reference 1, TVA has concluded it is prudent to further defer the field implementation of FMMS until completion of the revised hydraulic modeling and the submittal of license amendment request associated with the update to the WBN licensing basis. This will allow TVA to demonstrate what appropriate margin, if any, should be designed into additional flood mitigating systems at SQN and WBN. Therefore, TVA is revising the Commitment 1 due date (Enclosure 1 of Reference 1) to implement an FMMS at SQN Units 1 and 2, and WBN Units 1 and 2, from September 30, 2022, to September 30, 2024.
The enclosure to this letter provides the one revised regulatory commitment contained in this letter. If additional information is needed regarding this update, please contact Russell Thompson at rrthompson@tva.gov.
Respectfully, Stuart L. Rymer Director (Acting), Nuclear Regulatory Affairs
Enclosure:
Commitment cc (Enclosure):
NRR Director - NRC Headquarters NRC Regional Administrator - Region II NRC Project Manager - Sequoyah Nuclear Plant NRC Project Manager - Watts Bar Nuclear Plant NRC Senior Resident Inspector - Sequoyah Nuclear Plant NRC Senior Resident Inspector - Watts Bar Nuclear Plant Digitally signed by Rymer, Stuart Loveridge Date: 2022.06.30 10:48:17 -04'00'
CNL-22-070 E-1 of 1 ENCLOSURE COMMITMENT