Pilgrim Nuclear Power Station in Plymouth was shut down early Tuesday morning after a problem with a valve, officials said.
The valve was leaking steam used to drive the main turbine, Nuclear Regulatory Commission spokesman Neil Sheehan said.
The problem had nothing to do with the nuclear operation of the plant, Sheehan said.
The problem was discovered Monday night and the plant, which is owned by Entergy Nuclear Operations, was shut down by 6:30 a.m. Tuesday. This was a planned gradual shutdown, rather than a sudden, unplanned shutdown, known as a “scram,” Sheehan said.
Repairs to the valve are not expected to take a considerable amount of time, Sheehan said.
Pilgrim is already under additional oversight by the NRC due to the amount of scrams followed by complications experienced by the plant in the third quarter. The NRC will be sending a team to inspect the plant and address the issues, Sheehan said.