The beleaguered Fort Calhoun nuclear plant in Nebraska is temporarily offline because of a lockout of its main generator.
Omaha Public Power District (OPPD) officials said the plant automatically took its reactor and turbine offline Wednesday morning. Officials said the plant responded as designed.
Staffers are reviewing the cause of the generator lockout, but additional information was not immediately available. The Nuclear Regulatory Commission (NRC) is aware of the situation.
While the plant is offline, it remains at normal operating pressure and temperature.
Fort Calhoun, about 20 miles north of downtown Omaha, started back up in December 2013 after being offline since April 2011, when it went down for scheduled refueling. It was in a cold shutdown as floods overtopped the banks of the Missouri River, then placed under federal control after an electrical fire broke out and officials found a number of safety violations.
Since then, OPPD has spent $177 million on recommissioning the plant. That work entailed clearing a 450-item checklist of corrective items issued by the NRC.