LER-2024-001, Inoperability of Unit 3 Diesel Generator Due to Relay Failure |
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10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
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Post Office Box 2000, Decatur, Alabama 35609-2000 April 11, 2024 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, Units 1, 2, and 3 Renewed Facility Operating License Nos. DPR-33, DPR-52, and DPR-68 NRC Docket Nos. 50-259, 50-260, and 50-296
Subject:
Licensee Event Report 50-259/2024-001-00 The enclosed Licensee Event Report provides details of an inoperability of a Unit 3 Diesel Generator. The Tennessee Valley Authority (TVA) is submitting this report in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.73(a)(2)(i)(B), as any operation or condition which was prohibited by the plants Technical Specifications.
There will be a supplement to this Licensee Event Report to allow additional time to complete the cause evaluation.
There are no new regulatory commitments contained in this letter. Should you have any questions concerning this submittal, please contact David Renn, Site Licensing Manager, at (256) 729-2636.
Respectfully, Manu Sivaraman BFN Site Vice President
Enclosure:
Licensee Event Report 50-259/2024-001 Inoperability of Unit 3 Diesel Generator due to Relay Failure 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 February 14, 2024, while performing Surveillance Procedure 3-SR-3.8.1.9(3D OL), Diesel Generator 3D Emergency Load Acceptance Test with Unit 3 Operating, the Unit 3 D Emergency Diesel Generator (DG) did not start on an undervoltage condition on its associated safety bus as expected. A past operability evaluation determined that the DG had been inoperable since December 14, 2022.
During this event, the 3D DG would have continued to support the safety function of starting on the receipt of an accident signal as designed. Although the 3D DG would not have automatically started during a loss of offsite power, operators are directed to immediately ensure DGs are started and tied to their respective safety busses.
The causal analysis and corrective actions will be reported later in a supplement to this LER.
A. Immediate Corrective Actions
The failed SUDR relay was repaired and 3D DG was returned to Operable status on February 15, 2024.
B. Corrective Actions to Prevent Recurrence or to reduce the probability of similar events occurring in the future Corrective actions will be reported later in a supplement to this LER.
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 no similar events.
VIII. Additional Information
There is no additional information.
IX.
Commitments
There are no new commitments.
Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
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