Massachusetts' Pilgrim nuclear plant shut down automatically and relied on its diesel generators for backup power Monday after an offsite power disruption brought about its third unplanned outage in as many months.
An Entergy spokeswoman told the Patriot Ledger that an offsite power line failed at 9:21 p.m. while a second 345-kilovolt line was undergoing maintenance by Northeast Utilities subsidiary NStar. The shutdown proceeded safely, and the generators provided power to remove decay heat from the reactor while offsite electricity was being restored.
Last month, operators powered the plant down to troubleshoot a small steam leak, and they manually tripped the boiling water reactor in August when an electrical problem stopped its main feedwater pumps. The plant was refueled in May, but its full restart was delayed by a small oil-pump fire in its turbine hall.
According to the Patriot Ledger, Pilgrim had been offline 73 of 288 days in 2013, as of Tuesday, including the 46-day refueling outage.