An electrical malfunction triggered an automatic shutdown of the Salem Unit 2 reactor Wednesday afternoon, with the cause still under investigation.
The system had been online for 387 consecutive days before the shutdown at 3:39 p.m. Wednesday, said PSEG Nuclear spokesman Joe Delmar.
A circuit breaker on a part of the system that supplies one of the reactor’s coolant pumps shut off after a surge indication, a Nuclear Regulatory Commission (NRC) report said.
All safety systems operated as expected, with Salem’s reactor remaining in a stable mode, Delmar said.
Salem Unit 1 and the nearby Hope Creek nuclear plant were unaffected.
The NRC’s performance oversight system shows that Unit 2 has not had any previous unplanned, automatic shutdowns since the first quarter of 2014, and no unplanned power changes since the first quarter of this year. Reactor tracking systems require stepped up oversight if plants record three or more unplanned shutdowns over the most-recent 7,000 hour, or nearly 10-month, period.
PSEG Nuclear, part of Public Service Enterprise Group, operates three reactors on Artificial Island in New Jersey, along the Delaware River southeast of Port Penn. Artificial Island ranks as the nation’s second largest nuclear generating complex.
During the last refueling shutdown at Salem Unit 2, which began in April 2014, workers discovered broken bolts in all four of the plant’s cooling water pumps. The problem, linked to the type of metal used in the bolts, led to a costly extension of the plant’s idling.