05000325/LER-2024-002, Re Automatic Start of Emergency Diesel Generator Due to Emergency Bus De-energization
| ML24102A124 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 04/10/2024 |
| From: | Krakuszeski J Duke Energy Progress |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| RA-24-0075 LER 2024-002-00 | |
| Download: ML24102A124 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 3252024002R00 - NRC Website | |
text
~ ~ DUKE
~ ENERGY April 10, 2024 Serial: RA-24-0075 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
Subject:
Brunswick Steam Electric Plant, Unit Nos. 1 and 2 Renewed Facility Operating License Nos. DPR-71 and DPR-62 Docket Nos. 50-325 and 50-324 Licensee Event Report 1-2024-002 John A. Krakuszeski Vice President Brunswick Nuclear Plant 8470 River Rd SE Southport, NC 28461 o: 910.832.3698 10 CFR 50.73 In accordance with the Code of Federal Regulations, Title 10, Part 50.73, Duke Energy Progress, LLC, is submitting the enclosed Licensee Event Report (LER). This report fulfills the requirement for a written report within sixty (60) days of a reportable occurrence.
This document contains no regulatory commitments.
Please refer any questions regarding this submittal to Mr. Mark DeWire, Manager - Nuclear Support Services, at (910) 832-6641.
Sincerely, John A. Krakuszeski
Enclosure:
Licensee Event Report
U.S. Nuclear Regulatory Commission Page 2 of 2 cc (with enclosure):
Ms. Laura Dudes, NRC Regional Administrator, Region II Mr. Luke Haeg, NRC Project Manager Mr. Gale Smith, NRC Senior Resident Inspector
Abstract
At approximately 23:25 Eastern Standard Time (EST) on February 18, 2024, with Unit 1 in Mode 5 at 0 percent power during a planned refueling outage and Unit 2 in Mode 1 at 100 percent power, Emergency Bus E-2 de-energized. Emergency Diesel Generator (EDG) 2 automatically started and re-energized E-2, as designed. The de-energization of E-2 also resulted in Unit 1 Primary Containment Isolation System (PCIS) partial Group 2, Group 6, and partial Group 10 isolations. The PCIS actuations were as expected for the outage plant line up on Unit 1 at the time.
The de-energization of E-2 occurred during a planned transfer of E-2 Direct Current (DC) control power from normal to alternate for the 1B-1 battery. During this control power transfer the E-2 degraded voltage relays mis-operated and caused E-2 to de-energize.
There was no impact on the health and safety of the public or plant personnel. This event is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A) due to actuation of PCIS and EDG 2. This event is also being reported for Unit 2 due to Brunswicks interconnected electrical distribution system.
(See Page 2 for required number of digits/characters for each block)
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
Corrective Actions
The mis-operating degraded voltage relays were replaced.
In addition, the procedure associated with transferring control power is planned to be revised to preclude a relay mis-operation resulting in a similar event in the future. Procedure revisions are planned to be completed by April 25, 2024.
Any changes to corrective actions or completion schedules will be made in accordance with the sites corrective action program.
Previous Similar Events
No previous similar events have occurred within the past 20 years in which mis-operating degraded voltage relays caused an Emergency Bus to de-energize.
Commitments
No regulatory commitments are contained in this report.