05000400/LER-2022-007-01, Automatic Reactor Trip Due to Loss of Power from the a Auxiliary Bus
| ML23026A333 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 01/26/2023 |
| From: | Hoffman D Duke Energy Progress |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| RA-23-0013 LER 2022-007-01 | |
| Download: ML23026A333 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| 4002022007R01 - NRC Website | |
text
d_-, DUKE
~ ENERGY~
January
, 2023 Serial: RA-23-0013 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 2022-007-01 Ladies and Gentlemen:
David S. Hoffman Plant 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 2022-007-01 in accordance with 1 O CFR 50. 73 for Shearon Harris Nuclear Power Plant, Unit 1 (HNP). This report is a planned supplement to LER 2022-007-00 submitted on December 20, 2022. 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.
David S. Hoffman Enclosure: Licensee Event Report 2022-007-01 cc:
P. Boguszewski, NRC Senior Resident Inspector, HNP M. Mahoney, NRC Project Manager, HNP NRC Regional Administrator, Region II 26
Abstract
Shearon Harris Nuclear Power Plant, Unit 1
00400 3
Automatic Reactor Trip due to Loss of Power from the A Auxiliary Bus 10 30 2022 2022 007 01 01 26 2023 1
016
Sarah McDaniel, Regulatory Affairs Engineer (984) 229-2002 A
EA XCT S188 Y
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. Corrective actions involved rewiring of the CTs in accordance with design.Page of
- 3. LER NUMBER YEAR SEQUENTIAL NUMBER REV NO.
052 050
D. Corrective Actions
Corrective actions involved rewiring of the differential CTs in accordance with design. An extent of condition review was completed on CT connections on other auxiliary buses that had maintenance completed in the refueling outage and no additional wiring errors were identified.
Accountability actions for individuals involved in the development of the lift/land sheets that lacked unique cable identifiers required by procedure will be completed. Maintenance personnel will receive training on lift/land sheet usage. Additionally, procedural guidance to improve the lift/land process will be implemented. A standing order has already been implemented to prescribe supervisor reviews of configuration control sheets prior to implementation, which will remain in effect until the improved procedural guidance is implemented. Procedural guidance that clarifies the conditions for utilizing wire land verification as a post-maintenance test to ensure risk has been evaluated will also be implemented.
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.
3 3
Shearon Harris Nuclear Power Plant, Unit 1 00400 2022 007 01