05000400/LER-2022-007, Automatic Reactor Trip Due to Loss of Power from the ‘A’ Auxiliary Bus
| ML22354A199 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 12/20/2022 |
| From: | Gunter W Duke Energy Progress |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| RA-22-0332 LER 2022-007-00 | |
| Download: ML22354A199 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| 4002022007R00 - NRC Website | |
text
20 J_., DUKE
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December
, 2022 Serial: RA-22-0332 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Shearon Harris Nuclear Power Plant, Unit 1 Docket No. 50-400/Renewed License No. NPF-63 Subject: Licensee Event Report 2022-007-00 Ladies and Gentlemen:
William Gunter Nuclear Support Services Manager Shearon Harris Nuclear Power Plant 5413 Shearon Harris Road New Hill, NC 27562-9300 10 CFR 50.73 Duke Energy Progress, LLC, submits the enclosed Licensee Event Report 2022-007-00 in accordance with 10 CFR 50. 73 for Shearon Harris Nuclear Power Plant, Unit 1 (HNP). On October 30, 2022, with HNP in Mode 1, an automatic reactor trip occurred due to an under-voltage condition on the 'A' reactor coolant pump (RCP) and the 'C' RCP that resulted from a loss of power from the 'A' auxiliary bus. This event had no significance with respect to the health and safety of the public.
There are no regulatory commitments contained within this report.
Please refer any questions regarding this submittal to Sarah McDaniel at (984) 229-2002.
Sincerely, William Gunter Enclosure: Licensee Event Report 2022-007-00 cc:
P. Boguszewski, NRC Senior Resident Inspector, HNP M. Mahoney, NRC Project Manager, HNP NRC Regional Administrator, Region II
Abstract
Shearon Harris Nuclear Power Plant, Unit 1 400 3
Automatic Reactor Trip due to Loss of Power from the A Auxiliary Bus 10 30 2022 2022 007 00 12 20 2022 1
016
Sarah McDaniel, Regulatory Affairs Engineer (984) 229-2002 A
EA XCT S188 Y
02 28 2023 At 06:53 Eastern Daylight Time, with Shearon Harris Nuclear Power Plant, Unit 1, in Mode 1, at sixteen percent power following the completion of a refueling outage, an automatic reactor trip occurred due to an under-voltage condition on the 'A' reactor coolant pump (RCP) and the 'C' RCP that resulted from a loss of power from the A auxiliary bus. Power was lost from the 'A' auxiliary bus while operators were performing a procedure to transfer power from the 'A' start-up transformer to the 'A' unit auxiliary transformer (UAT). With the loss of power from the A auxiliary bus, the A main feedwater pump (MFP) tripped. The B MFP was not in service and with the loss of the last running MFP, the auxiliary feedwater system actuated as designed. Safety systems functioned as required. This event did not impact public health and safety. An investigation determined that the current transformers (CTs) in the 1A-3 cubicle were mis-wired, resulting in a differential current protective relay sensing the equivalent of a differential current in the C phase on the A auxiliary bus. When current was applied through the A UAT to the 1A-3 cubicle, the differential current protective relay actuated, which actuated the lockout of the A auxiliary bus. The wiring error occurred during maintenance activities on the CTs that were reinstalled during the refueling outage. Causal factors for the wiring error will be determined from the ongoing cause evaluation. Once the evaluation is complete, a supplemental report will be issued containing the causal factors for this event. Corrective actions involved rewiring of the CTs in accordance with design.
Additional actions will be determined following completion of the cause evaluation.
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E. Safety Analysis
Following the reactor trip, the A auxiliary bus was able to be reenergized from the A SUT. The reactor trip was not complex, with all safety systems functioning as designed during and following the reactor trip. The automatic reactor trip had no impact on public health and safety. The plant is designed for a loss of main feedwater and plant systems responded as expected for this condition.
F. Additional Information
There have been no events at HNP similar to the event documented in this LER in the past three years.
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