ENS 52468
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ENS Event | |
|---|---|
03:29 Dec 29, 2016 | |
| Title | Loss of Safety Function Due to Two Inoperable Standby Liquid Control Subsystems |
| Event Description | On December 28, 2016 at 2119 EST, the Standby Liquid Control system (SLC) subsystem A was declared inoperable in accordance with the surveillance instruction for performance of a routine surveillance test. At 2229 EST, control room operators received an out-of-service alarm for the explosive-actuated injection valve for SLC subsystem B and declared subsystem B inoperable, thereby rendering both subsystems inoperable. With both subsystems inoperable, the SLC system was unable to fulfill its safety function. At 2335, the surveillance was completed and subsystem A was restored to operable status, which restored the ability for the system to fulfill its safety function.
Troubleshooting determined that the cause for subsystem B inoperability was an intermittent electrical connection for the explosive-actuated injection valve. Repairs were conducted and the subsystem was restored to operable status on December 29, 2016 at 1708 EST. This issue was entered into the Corrective Action Program and during post reportability review, it was determined that this was a reportable event under 10 CFR 50.72(b)(3)(v)(A) for an event or condition that could have prevented the fulfillment of a safety function of a system that is needed to shut down the reactor and maintain it in a safe shutdown condition and under 10 CFR 50.72(b)(3)(v)(D) for a system that was unavailable for accident mitigation. The NRC Resident Inspector has been notified. |
| Where | |
|---|---|
Perry  Ohio (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| LER: | 05000440/LER-2016-004 |
| Time - Person (Reporting Time:+35.18 h1.466 days <br />0.209 weeks <br />0.0482 months <br />) | |
| Opened: | David Duesing 14:40 Dec 30, 2016 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Dec 30, 2016 |
| 52468 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (98 %) |
| After | Power Operation (98 %) |
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