Nuclear Event – Manual Reactor Trip: Watts Bar Nuclear Plant (Unit 2), Tennessee
North America – USA | State of Tennessee, Rhea County, Spring City, Watts Bar Nuclear Plant
Location: 35°36’10.0″N 84°47’22.0″W
Site Operational Age: ~32 years
Event: RPS ACTUATION – CRITICAL/MANUAL REACTOR TRIP/HOT STANDBY
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) – RPS ACTUATION – CRITICAL
50.72(b)(3)(iv)(A) – VALID SPECIF SYS ACTUATION
Nuclear Event in USA on Monday, 20 March, 2017 at 08:13 [EDT].
MANUAL REACTOR TRIP AS A RESULT OF SECONDARY PLANT TRANSIENT
“On March 20, 2017 at 0813 EDT, Watts Bar Nuclear Plant (WBN) Unit 2 operations personnel manually tripped the plant from approximately 91 percent power based on lowering steam generator levels. Prior to the plant trip, the 2A Hotwell pump tripped at 0758 EDT and the 2C Condensate Booster Pump subsequently tripped at 0802 EDT. Operations personnel commenced to lower plant power after the 2A Hotwell pump trip in an attempt to maintain steam generator levels, but were unable to recover level and manually tripped the unit.
“All control rods fully inserted and all automatically actuated safety related equipment operated as designed. At 0905 EDT, operations personnel exited the emergency operating instructions after the plant was stabilized. The cause of the event is under investigation.
“This event is reportable to the NRC within four hours under 10 CFR 50.72(b)(2)(iv)(B) as a result of the actuation of the Reactor Protection System and in eight hours under 10 CFR 50.72(b)(3)(iv)(A) as a result of actuation of the Auxiliary Feedwater system.
“The licensee notified the NRC Resident Inspector.”
Source: NRC Event Number: 52625