The Hope Creek nuclear reactor had operated for 138 consecutive days until Monday night's shutdown.
LOWER ALLOWAYS CREEK TWP. -- PSEG Nuclear's Hope Creek reactor has shut down after two key pumps stopped operating, officials said.
The reactor went off-line at 8:46 p.m., Monday, according to Joe Delmar, spokesman for the plant's operator, PSEG Nuclear.
Both of the plant's two recirculating pumps tripped at the same time, Delmar said. The pumps control the circulation of cooling water through the reactor and that flow helps to control reactor power.
What caused the pumps to trip still remained under investigation Tuesday morning.
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Neil Sheehan, spokesman for the Nuclear Regulatory Commission which oversees the operation of the nation's nuclear plants, said the shutdown happened during the testing of a safety system.
Sheehan said the test was to confirm all the circuits and equipment are operating properly.
He said the plant responded as designed and NRC inspectors at the plant responded and observed the shutdown.
"There were no immediate safety concerns," Sheehan said.
Delmar said it was not known when the reactor would be returned to service.
Hope Creek had been in service for 138 days before Monday's shutdown.
It is one of three reactors operated by PSEG Nuclear at the Island.
The other two -- Salem 1 and Salem 2 -- remained operating at full power Tuesday, according to Delmar.
The three units comprise the second-largest commercial nuclear generating complex in the United States.
There are four nuclear reactors operating in New Jersey -- the three in Lower Alloways Creek and Oyster Creek in Lacy Township, Ocean County.
Bill Gallo Jr. may be reached at bgallo@njadvancemedia.com. Follow South Jersey Times on Twitter @TheSJTimes. Find NJ.com on Facebook.
