ENS Event | |
|---|---|
21:51 Jul 22, 2021 | |
| Title | Unanalyzed Condition of Fire Safe Shutdown Equipment |
| Event Description | On July 20, 2021, at 1707 EDT, an apparent non-compliance with 10 CFR 50, Appendix R, section III.G.2 (separation of redundant fire safe shutdown equipment) was identified. This issue was initially categorized as not affecting train separation or the ability of the equipment to perform their Design Basis functions. The original concern was entered into the licensee's Corrective Action Program as CR1177199.
Subsequently, on July 22, 2021, at 1751 EDT, a further 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 breaker position interlocks routed to or through non-safety related components or spaces may affect the ability to provide emergency power on the affected unit due to impacts on the control power circuits during an Appendix R fire associated with a loss of offsite power. The following are the affected fire areas: - Unit 1 and Unit 2 Turbine Buildings - Unit 1 and Unit 2 Cable Spreading Rooms - Unit 1 and Unit 2 Normal (307) Switchgear Rooms This condition is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(B). This is also reportable as a 60-day written report pursuant to 10 CFR 50.73(a)(2)(ii)(B). This event was entered into the licensee's Corrective Action Program as CR 1177399. The NRC Resident Inspector has been notified of this event. |
| Where | |
|---|---|
North Anna  Virginia (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| Time - Person (Reporting Time:+-1.38 h-0.0575 days <br />-0.00821 weeks <br />-0.00189 months <br />) | |
| Opened: | Marc Hofmann 20:28 Jul 22, 2021 |
| NRC Officer: | Ossy Font |
| Last Updated: | Jul 22, 2021 |
| 55375 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 553752021-07-22T21:51:00022 July 2021 21:51:00
[Table view]10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition of Fire Safe Shutdown Equipment ENS 514602015-10-08T01:47:0008 October 2015 01:47:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition High Energy Line Break Door Found Unlatched ENS 472012011-08-26T17:00:00026 August 2011 17:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Based on Seismic Activity That Potentially Exceeded Design Basis Earthquake Magnitude 2021-07-22T21:51:00 | |