Nuclear Event – (Automatic Reactor Scram) Hot Shutdown: Grand Gulf Nuclear Station, Mississippi
Technological Hazard – Nuclear Event
North America – USA | State of Mississippi, Claiborne County, Port Gibson, Grand Gulf Nuclear Station
Location: 32°00’24.0″N 91°02’54.0″W
Present Operational Age: ~30 years
Event: RPS ACTUATION – CRITICAL/HOT SHUTDOWN
Nuclear Event in USA on Friday, 17 June, 2016 at 02:57 [CDT]
AUTOMATIC REACTOR SCRAM DURING TESTING
“During planned stop and control valve testing, two main turbine high pressure stop valves closed instead of the expected one (stop valve ‘B’). This caused the main turbine control valves, power, reactor pressure to swing and a division 2 half SCRAM. Control rods were inserted to reduce power and the power swings. At 0257 [CDT] the reactor automatically SCRAMMED. Reactor SCRAM, Turbine Trip [procedures] ONEPs and EP-2 were entered. Reactor water level was stabilized at 34 inches narrow range on startup level control and reactor pressure stabilized at 884 psig using main turbine bypass valves. No other safety related systems actuated and all systems performed as expected.”
The plant is in its normal shutdown electrical lineup using normal feedwater and turbine bypass valves for decay heat removal. Reactor pressure is slowly trending down. The licensee is investigating the cause of the second stop valve shutting.
The licensee notified the NRC Resident Inspector.
Nuclear Event in USA on Tuesday, 29 March, 2016 at 11:23 [CDT]. REACTOR SCRAM DUE TO TURBINE TRIP