05000259/LER-2021-001-01, Volt Load Shed Logic Inoperable Longer than Allowed by Technical Specifications Due to Failed Relay
| ML22188A133 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/06/2022 |
| From: | Rasmussen M Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 2021-001-01 | |
| Download: ML22188A133 (10) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 2592021001R01 - NRC Website | |
text
Post Office Box 2000, Decatur, Alabama 35609-2000 July 6, 2022 10 CFR 50.73 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Units 1 and 2 Renewed Facility Operating License Nos. DPR-33 and DPR-52 NRC Docket Nos. 50-259 and 50-260
Subject:
Licensee Event Report 50-259/2021-001-01
Reference:
TVA Letter to NRC dated November 22, 2021, "Licensee Event Report 50-259/2021-001-00" [ML21326A027]
The enclosed Licensee Event Report (LER) provides additional details of the 480 Volt Load Shed Logic Inoperable Longer than Allowed by Technical Specifications (TS) due to Failed Relay. 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 TSs and 50.73(a)(2)(v), as any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to (A) shut down the reactor and maintain it in a safe shutdown condition; (B) remove residual heat; (C) control the release of radioactive material; or (D) mitigate the consequences of an accident.
This revision to the referenced letter adds information regarding the failure to comply with TS 3.0.4 during a Mode change on Unit 2.
There are no new regulatory commitments contained in this letter. Should you have any questions concerning this submittal, please contact Christopher L. Vaughn, Nuclear Site Licensing Manager, at (256) 729-2636.
Respectfully, Matthew Rasmussen Site Vice President Browns Ferry Nuclear Plan IRU Respectfully, M tth R
U.S. Nuclear Regulatory Commission Page 2 July 6, 2022 Enclosure: Browns Ferry Nuclear Plant, Units 1 and 2, Licensee Event Report 50-259/2021-001 480 Volt Load Shed Logic Inoperable Longer than Allowed by Technical Specifications due to Failed Relay cc (w/ Enclosure):
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant NRC Project Manager - Browns Ferry Nuclear Plant
ENCLOSURE Browns Ferry Nuclear Plant Units 1 and 2 Licensee Event Report 50-259/2021-001-01 480 Volt Load Shed Logic Inoperable Longer than Allowed by Technical Specifications due to Failed Relay See Enclosed
Abstract
On September 23, 2021 at 02:00 CDT (Central Daylight Time), the Units 1 and 2 480 Volt (V) Load Shed Logic, Division I was declared inoperable during the performance of surveillance testing. During the performance of this surveillance procedure, relay 0-RLY-231-00A7 would not have energized when required due to an open circuit in the coil. The relay was replaced and the Units 1 and 2 480 V Load Shed Logic, Division I was declared operable on September 25, 2021 at 22:30 CDT.
An engineering evaluation of the relay failure was completed on October 28, 2021. This evaluation determined that 0-RLY-231-00A7 was likely inoperable since the last time it had been energized during testing on March 3, 2021. Additionally, the Units 1 and 2 480 V Load Shed Logic, Division II was out of service twice during this time period to support testing on March 4, 2021 and May 19, 2021.
Examination of the relay determined that the relay failed due to an internal failure of the coil with no external damage seen.
Page 7 of 7 B. Corrective Actions to Prevent Recurrence or to reduce the probability of similar events occurring in the future Additional review could not determine a cause of the failure. No damage was visible and no failure trends were identified.
VII. Previous Similar Events at the Same Site
There were no previous similar events occurring at BFN within the last three years.
VIII. Additional Information
There is no additional information.
IX.
Commitments
There are no new commitments.