05000280/LER-2021-001, Unanalyzed Condition Due to Appendix R Concern Identified with Cable Separation
| ML21315A001 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 11/11/2021 |
| From: | Lawrence D Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 21-343 LER 2021-001-00 | |
| Download: ML21315A001 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition |
| 2802021001R00 - NRC Website | |
text
10CFR50.73 Virginia Electric and Power Company Surry Power Station 5570 Hog Island Road Surry, Virginia 23883 Serial No.:
SPS:
Docket No.:
License No.:
21-343 MMT 50-280 50-281 DPR-32 DPR-37 Pursuant to 10CFR50.73, Virginia Electric and Power Company hereby submits the following Licensee Event Report applicable to Surry Power Station Unit 1 and Unit 2.
Report No. 50-280 / 2021-001-00 This report has been reviewed by the Station Facility Safety Review Committee and will be forwarded to the Management Safety Review Committee.
Douglas Site Vice esident Surry Power Station Enclosure Commitment contained in the LER: None cc:
U.S. Nuclear Regulatory Commission, Region II Marquis One Tower, Suite 1200 245 Peachtree Center Ave., NE Atlanta, GA 30303-1257 NRC Senior Resident Inspector Surry Power Station November 11, 2021 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555-0001
Dear Sir or Madam:
Abstract
On September 13, 2021, at 1822 EDT, an apparent non-compliance with 10 CFR 50, Appendix R, Section III.G.2 (separation of redundant fire safe shutdown equipment) was identified based on Operating Experience (OE) from North Anna Power Station (LER 2021-002-00). A review of the affected control circuits for the Unit 1 and Unit 2 Emergency Diesel Generator (EDG) output breakers and Emergency Bus feeder breakers identified a concern that damage to the control power circuits during a fire may affect the ability to provide emergency power on both units. An 8-hour non-emergency report was made per 10 CFR 50.72(b)(3)(ii)(B) for an unanalyzed condition. Fire watches were established in the affected areas.
The cause of this condition is the stations original post-fire safe shutdown analysis did not accurately assess the impact on the equipment from associated cable damage due to fire for the select cables. Risk mitigating actions have been developed, implemented, and will continue to be performed until appropriate permanent corrective actions are in place to mitigate this condition.
This event is reportable in accordance with 10 CFR 50.73(a)(2)(ii)(B) for Any event or condition that resulted in the nuclear power plant being in an unanalyzed condition that significantly degraded plant safety.
11 11 2021Page of 05000-
- 3. LER NUMBER YEAR SEQUENTIAL NUMBER REV NO.
3 3
Surry Power Station, Unit 1 280 2021 001 00
4.0 Immediate Corrective Action
Fire watches were established in the Unit 1 Normal Switchgear Room, Unit 1 Cable Tray Room, Unit 1 Emergency Switchgear Room, and Unit 2 Cable Vault and Tunnel to mitigate the risk of fire and aid in early detection of fire. Risk mitigating actions have been developed, implemented, and will continue to be performed until appropriate permanent corrective actions are in place to mitigate this condition.
5.0 Additional Corrective Actions
A Reasonable Assurance of Safety (RAS) was developed with risk mitigating actions implemented until final resolution is completed. Procedures ECA-0.0 (Loss of All AC Power) and Flex Support Guidelines (FSGs) were reviewed to mitigate the results of a loss of all AC power conditions. Periodic reviews of applicable procedures and Fire Fighting Strategies for fires in areas of concern have been established. Prior to any unavailability of the Turbine Driven Auxiliary Feedwater (TDAFW) pump (EIIS Component P, System BA), guidance has been provided to pre-stage the Beyond Design Basis (BDB) Auxiliary Feedwater Pump.
The station is currently evaluating design changes to eliminate the vulnerability.
6.0 Actions to Prevent Recurrence The applicable control cables associated with the EDG output breakers and Emergency Bus normal feeder breakers are planned to be modified or manual actions are planned to be established, where applicable, to regain compliance as required by Appendix R Safe Shutdown Analysis.
7.0 Similar Events
A review of internal operating experience was performed, and no similar events were identified that were previously reported to the Nuclear Regulatory Commission.
8.0 Additional Information
Units 1 and 2 continued to operate at 100% power.