21:40 Jul 12, 2019
Invalid Auto Isolation Signal of High Pressure Coolant Injection
At 1640 CDT on 7/12/19, Unit 1 High Pressure Coolant Injection (HPCI) received an invalid auto isolation signal which closed the HPCI steam supply valves rendering HPCI inoperable. This condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D), as an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.
The isolation occurred while performing a calibration and functional check of a level switch for the Unit 1 Core Spray system. Continuity was checked across the incorrect set of contacts which completed the circuit in logic bus 'A' for the auto isolation signal in the HPCI system. There was no impact to the safety of the public or plant personnel during the time HPCI system was isolated. HPCI was returned to operable at 2110 CDT on 7/12/19.
CR 1532094 documents this condition in the Corrective Action Program.The licensee has notified the NRC Resident Inspector
|Browns Ferry |
Alabama (NRC Region 2)
|10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident|
|Time - Person (Reporting Time:+1.17 h0.0488 days <br />0.00696 weeks <br />0.0016 months <br />)|
22:50 Jul 12, 2019
|NRC Officer:||Michael Bloodgood|
|Last Updated:||Jul 12, 2019|
|54162 - NRC Website|