The operators of a Plymouth nuclear power plant have shut it down to investigate what they called a minor leak at a valve on a pipe that carries steam.

    The Pilgrim Nuclear Power Station shut down the plant at about 5:45 a.m. Monday.

    In a statement, plant owner Entergy said workers are investigating the cause of the leak at a pilot valve on one of the plant's four safety relief valves.

    It said the plant ``is in a safe, stable condition and there is no threat to public safety.''

    The shutdown comes just four days after the 685-megawatt plant came back online after being shut down for seven days. That Jan. 10 shutdown came after the failure of an electrical relay caused Pilgrim's two large water recirculation pumps to automatically turn off. (Associated Press)