The Pilgrim nuclear plant shut down and multiple safety systems initiated Thursday when a problem with its feedwater pumps briefly caused the water level in the reactor to drop.
Operators tripped the reactor manually at 7:55 a.m. from 98 percent power, according to a report filed with the Nuclear Regulatory Commission. It indicated a main feedwater power supply breaker likely tripped, causing the pumps to stop. During the event, the reactor's water level dropped to -46 inches, according to the NRC. The water level triggered part of the primary containment isolation system, the high pressure coolant injection system and the reactor core isolation cooling system, as well as an automatic start of emergency diesel generators. Water levels quickly recovered, no emergency was declared, and the unit was cooled down without incident.
Entergy operates the General Electric Type 3 boiling water reactor southeast of Boston. The shutdown Thursday follows a refueling outage extended by a small fire in the plant's turbine hall in May and an automatic trip during a snowstorm and power outage in February.