05000259/LER-2024-004, Main Steam Relief Valves Lift Settings Outside of Technical Specifications Required Setpoints
| ML25010A346 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 01/10/2025 |
| From: | Komm D Tennessee Valley Authority |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| LER 2024-004-00 | |
| Download: ML25010A346 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2592024004R00 - NRC Website | |
text
Post Office Box 2000, Decatur, Alabama 35609-2000 January 10, 2025 10 CFR 50.73 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 50-259/2024-004 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 David J. Renn, Nuclear Site Licensing Manager, at (256) 729-2636.
Respectfully, Daniel A. Komm Site Vice President Enclosure: Licensee Event Report 50-259/2024-004 Main Steam Relief Valves Lift Settings Outside of Technical Specifications Required Setpoints 1\\14 TENNESSEE VALLEY AUTHORITY
U.S. Nuclear Regulatory Commission Page 2 January 10, 2025 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 November 12, 2024, the Tennessee Valley Authority (TVA) was notified of as-found testing results that two (2) 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 one MSRV failed above its setpoint due to corrosion bonding to the valve seats.
The other MSRV failed below its setpoint due to relaxed setpoint springs. All thirteen of the MSRV pilot valves were replaced during the Unit 1 Fall 2024 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 pilot discs. BFN will continue to verify that the springs pass spring rate testing during their rebuilding and replacing those which do not.
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ID Page 6 of 6 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.
BFN will take additional actions to verify that the springs associated with each low lliftpoint passes Spring Rate testing or is replaced.
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 50-296/2024-003-00, for Unit 3 Cycle 21 LER 50-260/2023-002-00, for Unit 2 Cycle 22 LER 50-259/2022-003-00, for Unit 1 Cycle 14 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
VIII. Additional Information
There is no additional information.
IX.
Commitments
There are no new commitments.