LOWER ALLOWAYS CREEK TOWNSHIP, N.J. (AP) — Workers have shut down a nuclear reactor in southern New Jersey after a leak was detected in the containment building.

The Nuclear Regulatory Commission says Salem Unit 1 in Lower Alloways Creek Township was shut down after slightly radioactive water was discovered leaking at a rate of 4 gallons a minute Thursday.

The NRC says the spill was confined to the plant’s containment building and there was no threat to the public or workers.

The initial investigation determined the leak came from packing on a pressurizer spray valve used in the reactor coolant system. The valve was last replaced during a refueling outage that began in April.

PSEG Nuclear says the leaking water went through the plant drain system as designed. It did not know when the unit will be returned to service.

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