05:00 Dec 4, 2018
Hpci Inoperable Due to Mechanical Draft Cooling Tower Fan Brake Inverter Failure
At 0935 EST on December 4, 2018, the Division 2 Mechanical Draft Cooling Tower (MDCT) fans were declared inoperable due to failure of the over speed fan brake inverter. The brakes prevent fan over speed from a design basis tornado. The MDCT fans are required to support operability of the Ultimate Heat Sink (UHS). The UHS is required to support operability of the Division 2 Emergency Equipment Cooling Water (EECW) system. The EECW system cools various safety related components, including the High Pressure Coolant Injection (HPCI) system room cooler. An unplanned HPCI inoperability occurred based on a loss of the HPCI Room Cooler. Investigation into why the Division 2 MDCT fan over speed brake inverter failed is in progress. This report is being made pursuant to 10 CFR 50.72(b)(3)(v)(D) based on an unplanned HPCI inoperability.
The NRC Resident Inspector has been notified.Fermi 2 is in a 14-day LCO for inoperability of HPCI and a 72-hour LCO for UHS inoperability.
Michigan (NRC Region 3)
|10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident|
|LER:||look for an ler...|
|Time - Person (Reporting Time:+8.58 h|
13:35 Dec 4, 2018
|NRC Officer:||Bethany Cecere|
|Last Updated:||Dec 4, 2018|
|53772 - NRC Website|
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