Nuclear Event South Carolina

Officials with the U.S. Nuclear Regulatory Commission and Progress Energy are looking into an unplanned reactor shutdown that occurred at the H.B. Robinson Nuclear Plant near Hartsville on Monday. "We had an automatic plant trip," said Progress Energy spokesperson Jessica Lambert, who said a faulty electrical relay caused the shutdown. Progress Energy owns and operates the plant. The incident happened at about 11:45 a.m., Lambert said. She said the shutdown occurred when the system that monitors the flow of coolant through the reactor's coolant system indicated a low flow of coolant in the system. Lambert said plant officials have now determined that the incident resulted from a failed electrical relay in the reactor protection system and not from a problem in the coolant system. The reactor was still down on Wednesday, and Lambert said plant personnel are working to make the needed repairs to bring it back into service soon. "Of course, the NRC has on-site inspectors here, and we are working very closely with them," Lambert said. "It was an automatic shutdown," said NRC Region II spokesman Roger Hannah. "There was nothing complicated about it." Hannah said the reactor system is designed to shut down automatically in the event of a low coolant flow signal. "Everything worked like it was supposed to," he said. "We're following up with our resident inspectors on site." The shutdown occurred just days before the NRC was supposed to close a final deficiency finding related to performance at Robinson and problems resulting in unplanned shutdowns that occurred in 2009 and 2010 that resulted in heightened oversight of the Robinson facility by the regulatory agency. That finding was to have been closed this Friday unless additional findings occurred before then.