Nuclear Event – Accident Mitigation: Three Mile Island Nuclear Station, Unit 1, Pennsylvania
Technological Hazard (Nuclear Event) – Emergency Alert
North America – USA | State of Pennsylvania, Middletown, Three Mile Island Nuclear Station, Unit 1
Location: 40°09’14.0″N 76°43’29.0″W
Present Operational Age: ~42 years
Event: ACCIDENT MITIGATION CONDITION RESULTING IN LOSS OF SAFETY FUNCTION
Nuclear Event in USA on Tuesday, 28 June, 2016 at 10:55 [EDT].
BOTH A & B TRAINS HPI INOPERABLE DUE TO VOID IN COMMON SUCTION LINE RESULTING IN LOSS OF SAFETY FUNCTION
“At 1055 [EDT] on 06/28/16 a gas void was found during the monthly surveillance inspection located in the common suction line to the High Pressure Injection / Makeup (HPI / MU) pumps. At 1150 on 06/28/16 the HPI suction line cross-connect valves were closed to isolate and separate the ‘A’ & ‘B’ Trains of HPI. The ‘A’ train of HPI was declared degraded and initiated a 72 hour LCO [Limiting Condition of Operation] under TS [Technical Specification] 3.3.2. Investigation and analysis by Engineering determined that the size of the void did not meet the acceptance criteria for system operability. Due to the size of the void and location at time of discovery, both trains of HPI were determined to be inoperable until the suction cross connect valves were closed.
“This condition is reportable under 10 CFR 50.72(b)(3)(v)(D) as a Condition That Could Have Prevented Fulfillment of a Safety Function to mitigate the consequences of an accident. The void is being vented to restore a water-solid condition. The last successful surveillance was conducted on 05/31/16. The cause of the void is being investigated.
“The NRC Resident Inspector has been informed.”
Nuclear Event in USA on Monday, 05 October, 2015 at 21:15 [EDT]. ALERT DECLARATION DUE TO FIRE IN THE AUXILIARY BUILDING
Nuclear Event in USA on Wednesday, 06 May, 2015 at 19:14 (07:14 PM) UTC. REACTOR SHUTDOWN DUE TO ELECTRICAL FAULT WITH CONTROL ROD MECHANISM