The 1,109 MWe Unit 1 at the Vogtle nuclear power plant in Georgia shut down automatically during a maintenance outage August 31.
Southern Co. (NYSE: SO) said in a release that safety systems operated as designed and expected. The 1,127 MW Unit 2 is currently at 97 percent power and is preparing for a routine refueling outage. Both units are Westinghouse four-loop pressurized water reactors. Unit 1 began operations in 1987.
A spokesperson was quoted as saying that workers noticed water levels rising inside the unit's steam generator during work involving a valve controlling water flow.
Plant Vogtle is the site for two new proposed 1,100 MW Westinghouse AP1000 reactors. The company is awaiting final permits from the Nuclear Regulatory Commission before construction on units 3 and 4 can begin.