05000259/LER-2022-003, Main Steam Relief Valves Lift Settings Outside of Technical Specifications Required Setpoints
| ML23037A992 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  (DPR-033) |
| Issue date: | 02/06/2023 |
| From: | Sivaraman M Tennessee Valley Authority |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| LER 22-003-00 | |
| Download: ML23037A992 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2592022003R00 - NRC Website | |
text
Post Office Box 2000, Decatur, Alabama 35609-2000 February 6, 2023 10 CFR 50.73 10 CFR 50.4(a)
ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Unit 1 Renewed Facility Operating License No. DPR-33 NRC Docket No. 50-259
Subject:
Licensee Event Report 50-259/2022-003 Main Steam Relief Valves Lift Settings Outside of Technical Specifications Required Setpoints The enclosed Licensee Event Report provides details of Main Steam Relief Valves which failed to meet their Surveillance Requirements for longer than allowed by plant Technical Specifications. The Tennessee Valley Authority is submitting this report in accordance with Title 10 of the Code of Federal Regulations 50.73(a)(2)(i)(B), as any operation or condition which was prohibited by the plants Technical Specifications.
There are no new regulatory commitments contained in this letter. Should you have any questions concerning this submittal, please contact Chris L. Vaughn, Site Licensing Manager, at (256) 729-2636.
Respectfully, Manu Sivaraman Site Vice President Enclosure: Licensee Event Report 50-259/2022-003 Main Steam Relief Valves Lift Settings Outside of Technical Specifications Required Setpoints
U.S. Nuclear Regulatory Commission Page 2 February 6, 2023
cc (w/ Enclosure):
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant NRC Project Manager - Browns Ferry Nuclear Plant
Abstract
On December 6, 2022, the Tennessee Valley Authority was notified of As-Found testing results that two Main Steam Relief Valves (MSRVs) from Browns Ferry Nuclear Pant (BFN), Unit 1 were outside of their Surveillance Requirement limits for an indeterminate amount of time. These affected valves remained capable of maintaining reactor pressure within the American Society of Mechanical Engineers code limits and were still able to perform their safety function.
It was determined that the MSRVs failed due to corrosion bonding to the valve seats and non-quantifiable leakage known as simmering. All thirteen of the MSRV pilot valves were replaced during the Unit 1 fall 2022 refueling outage. The Boiling Water Reactor Owners' Group is continuing to work toward a solution to improve the quality and adhesion of the platinum coating on the discs.
Page 6 of 6 VI.
Corrective Actions
Corrective Actions are being managed by the TVAs corrective action program under Condition Reports (CRs), 962223, 1286467, 1410577, 1521190, 1658693, 1699286, 1775232, and 1822254.
A. Immediate Corrective Actions
All thirteen of the BFN, Unit 1 MSRV pilot valves were replaced with refurbished valves during U1R14. As left testing verified that these refurbished pilot valves were within +/- 1 percent of their setpoints.
B. Corrective Actions to Prevent Recurrence or to reduce the probability of similar events occurring in the future As discussed in LER 50-260/2021-002-00, a flaking issue has been noted with the platinum coated pilot discs. The Boiling Water Reactor Owners' Group (BWROG) is continuing to work toward a solution to improve the quality and adhesion of the platinum coating on the discs. The corrective actions suggested by the BWROG will be incorporated to correct setpoint drift. To reduce the probability of seat leakage occurring in the future, pilot seat rebuilds will be performed in valves that have low stellite in the seat.
VII. Previous Similar Events at the Same Site
A search of LERs from BFN, Units 1, 2, and 3 over the last five years identified seven LERs associated with MSRV lift settings outside of TS required setpoints:
LER 50-296/2022-001-00, for Unit 3 Cycle 20 LER 50-260/2021-002-00, for Unit 2 Cycle 21 LER 50-259/2020-003-01, for Unit 1 Cycle 13 LER 50-296/2020-002-00, for Unit 3 Cycle 19 LER 50-260/2019-002-00, for Unit 2 Cycle 20 LER 50-259/2018-007-00, for Unit 1 Cycle 12 LER 50-296/2018-004-00, for Unit 3 Cycle 18
VIII. Additional Information
There is no additional information.
IX.
Commitments
There are no new commitments.