Officials at Connecticut's nuclear power plant says one of its two operating units shut down due to low levels of the water used to cool the reactor core.
Millstone Power Station spokesman Ken Holt says Unit 3 shut down automatically on Friday night.
He said Monday an instrument that measures the flow of water into a steam generator lost power and the water was not diverted correctly. He said safety systems responded as they should.
Holt said the unit remains offline as the plant works to determine the cause of the malfunction.
A spokesman for the Nuclear Regulatory Commission says the shutdown was uncomplicated. Spokesman Neil Sheehan says inspectors will follow up on the company's efforts to diagnose what went wrong.
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