05000338/LER-2022-001, Automatic Reactor Trip During Control Rod Operability Testing
| ML22178A007 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 06/07/2022 |
| From: | Hilbert L Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 22-133 LER 2022-001-00 | |
| Download: ML22178A007 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 3382022001R00 - NRC Website | |
text
10CFR50.73 Virginia Electric and Power Company North Anna Power Station 1022 Haley Drive Mineral, Virginia 23117 June 7, 2022 Attention: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
Dear Sir or Madam:
Serial No.:
22-133 NAPS:
CNC 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. 50-338/2022-001-00 This report has been reviewed by the Facility Safety Review Committee and will be forwarded to the Management Safety Review Committee for its review.
Sincerely,
~~
Lisa Hilbert
~ite Vice President North Anna Power Station Enclosure Commitments contained in this letter: None cc:
United States Nuclear Regulatory Commission Region II Marquis One Tower
?45 Peachtree Center Ave., NE, Suite 1200 Atlanta, Georgia 30303-1257 NRC Senior Resident Inspector North Anna Power Station L
Abstract
On April 14, 2022, at 0928 hours0.0107 days <br />0.258 hours <br />0.00153 weeks <br />3.53104e-4 months <br /> with Unit 1 in Mode 1, 100 percent power, an automatic reactor trip occurred during the performance ofthe control rod operability periodic test. The reactor trip occurred during the manipulation of the rod control selector switch as part of the rod operability testing. A 4-hour and 8-hour non-emergency report was made per 10 CFR 50.72(8)
(2)(iv)(B) for RPS actuation (trip) and 10 CFR 50.72(b)(3)(iv)(A) for a valid actuation of an ESF system, respectively.
The cause of the event is currently under evaluation and will be provided at a later date as a supplement to this LER.
Unit 2 continued to operate at 99 percent power, Mode 1, during the event. The health and safety of the public were not affected by this event.
This event is reportable in accordance with 10 CFR 50.73(a)(2)(iv)(A) for RPS actuation (trip) and a valid actuation of the auxiliary feedwater system.
5.0 Additional Corrective Actions
Communication with Westinghouse was initiated to discuss the cause and the failed 1/0 Amplifier card and additional identified cards were sent to Westinghouse for further evaluation.
A work order was issued to address the relay that was found to be mechanically bound resulting in the 1-SD-MOV-102A/
B/C/D valves cycling. Work and associated testing were completed satisfactorily.
Compensating voltages were adjusted for the N-36 Intermediate Range Nuclear Instrumentation satisfactorily.
6.0 Actions to Prevent Recurrence A complete discussion of the actions to prevent recurrence will be-provided as a supplement to this LER after receiving and evaluating the results from Westinghouse failure analysis.
7.0 Similar Events
A review of internal operating experience was performed, and one similar event was identified:
On August 27, 1996, North Anna Unit 1 experienced an automatic reactor trip from 100 percent power with the initiating signal being "Hi Flux Rate - Reactor Trip" during Rod Operability testing when the Operator at the Controls.started to insert Control Bank "B." Multiple rods in Control Bank "B" Group 2 fell into the core. The cause was a faulty input/output isolation amplifier card in the Control Rod Drive System which failed to supply a full current - stationary current order to Control Bank "B" Group 2.
8.0 Additional Information
Unit 2 continued to operate at 99 percent power, Mode 1 during this event.
There were no releases of radioactive materials, radiation exposures or personnel injuries associated with this event. Page 3
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