Nuclear Event – Manual Reactor SCRAM (Hot Shutdown): Nine Mile Point Nuclear Station, Unit 1, New York
Nuclear Event in USA on Friday, 10 December, 2016 at 08:48 [EST].
MANUAL REACTOR SCRAM DUE TO HIGH MAIN TURBINE VIBRATIONS
“On December 10, 2016 at 0848 EST, [operators at] Nine Mile Point Unit 1 manually scrammed the reactor due to high vibrations on the Main Turbine. Cause of the high vibrations is being investigated.
“Following the scram, the High Pressure Coolant Injection (HPCI) system automatically initiated as expected. At Nine Mile Point Unit 1, a HPCI system actuation signal on low reactor pressure vessel (RPV) level is normally received following a reactor scram, due to level shrink. HPCI is a flow control mode of the normal feedwater system and is not an emergency core cooling system. At 0849, RPV level was restored above the HPCI system low level actuation set point and the HPCI system initiation signal was reset. Pressure control was established on the turbine bypass valves, the preferred system. No Electromatic relief valves actuated due to this scram.
“Nine Mile Point Unit 1 is currently in Hot Shutdown, with reactor water level and pressure maintained within normal bands. Decay heat is being removed via steam to the main condenser using the bypass valves. The offsite grid is stable with no grid restrictions or warnings in effect.
“The unit is currently implementing post scram recovery procedures.”
The licensee has notified the state of New York Public Service Commission and the NRC Resident Inspector.