05000338/LER-2024-003-01, Loss of Offsite Power Train a Relay Failure During Surveillance Testing
| ML25077A289 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 03/18/2025 |
| From: | Hilbert L Virginia Electric & Power Co (VEPCO) |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 25-001A LER 2024-003-01 | |
| Download: ML25077A289 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3382024003R01 - NRC Website | |
text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 10CFR50.73 Virginia Electric and Power Company North Anna Power Station 1022 Haley Drive Mineral, Virginia 23117 March 18, 2025 Attention: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
Dear Sir or Madam:
Serial No.:
25-001A NAPS:
RAP Docket Nos.: 50-338 License Nos.: NPF-4 Pursuant to 10CFR50.73, Virginia Electric and Power Company hereby submits the following Licensee Event Report applicable to North Anna Power Station Unit 1.
Report No. 50-338/2024-003-01 This report has been reviewed by the Facility Safety Review Committee and will be forwarded to the Management Safety Review Committee for its review.
- zaJ1--
Lisa Hilbert Site Vice President North Anna Power Station Enclosure Commitments contained in this letter: None cc:
United States Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, Georgia 30303-1257 NRC Senior Resident Inspector North Anna Power Station
Abstract
On November 12, 2024, at 0927 hours0.0107 days <br />0.258 hours <br />0.00153 weeks <br />3.527235e-4 months <br /> with Unit 1 in Mode 1, 100% power, while conducting routine surveillance testing under 1-PT-71.14, Loss of Offsite Power-Train A Operational Test for Auxiliary Feedwater Pumps, relay 1-EP-27 A-1 NNSF05-RELAY-F(0A-B) failed to actuate. Investigation into the event identified the relay disk was misaligned.
Unit 2 was not impacted by this event. Since the "A" train was not able to meet its surveillance requirement and was deemed inoperable since the previous surveillance, this event is reportable per 10 CFR 50.73(a)(2)(i)(B) for Operation or Condition Prohibited by Technical Specifications. The "B" train remained operable during this period; the safety function was maintained.
The health and safety of the public were not affected by this event.
1.0 Description of Event
- 2. DOCKET NUMBER
- 3. LER NUMBER I
00338 D
NUMBER NO.
I YEAR SEQUENTIAL REV
~-I 003 1-0 On November 12, 2024, at 0927 hours0.0107 days <br />0.258 hours <br />0.00153 weeks <br />3.527235e-4 months <br /> with Unit 1 in Mode 1, 100% power, while conducting routine surveillance testing under 1-PT-71.14, Loss of Offsite Power-Train A Operational Test for Auxiliary Feedwater Pumps, relay 1-EP-27A-1NNSF05-RELAY-F(0A-B) (EIIS System-ED, Component-27) failed to actuate. Investigation into the event identified the relay disk was misaligned. The relay disk was realigned and tested several times before performing the surveillance test satisfactorily.
This event is reportable per 10 CFR 50. 73(a)(2)(i)(B) for Operation or Condition Prohibited by Technical Specifications.
2.0 Significant Safety Consequences and Implications
The "B" train remained operable during this period; the safety function was maintained. The health and safety of the public were not affected by this event.
- 3. 0 Cause of the Event Investigation into the event identified that the relay disk was misaligned. The identified cause of the relay was vague procedural guidance that led to a failure to check for adequate mechanical clearance between the relay disk and coil/magnet assembly. While 1-PT-36.17 A "Channel Calibration For Station Blackout - Unit 1 Train A Bus 1 D And Bus 1 F" does include a step to check for obstruction in moving parts, it does not explicitly require verification of clearance between lhe induction disk and the magnet/coil assembly. The vague nature of this procedural step contributed to the failure to identify the misalignment.
~.0 Immediate Corrective Action Jhe relay disk was realigned and tested satisfactorily via 1-PT-71.14, at 1542 on November 12, 2024.
5.0 Additional Corrective Actions
There were no additional corrective actions beyond the initial repair.
6.0 Actions to Prevent Recurrence The associated periodic testing and electrical preventative maintenance procedures will be revised to ensure that the rotational disk in the relay is free from any obstructions and moves freely.
7.0 Similar Events
No similar events have been noted at North Anna.
- 8. 0 Additional Information I
- 2. DOCKET NUMBER
- 3. LER NUMBER 00338 I YEAR SEQUENTIAL REV
!2024 j NUMBER NO.
- - I 003 I -0 Unit 2 was not impacted by this event. The health and safety of the public were not affected by this event. Page 3
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