Unit 1 at the Catawba nuclear plant in South Carolina tripped Monday night after offsite power to the plant was cut.
The unit shut down normally just after 8 p.m., according to an event report from the Nuclear Regulatory Commission, and its four diesel emergency generators provided electricity until offsite AC power was restored at 1:35 a.m. Unit two had been shut down for refueling. Per NRC regulations, the plant declared an unusual event, the lowest of the NRC’s emergency declarations, which ended shortly after offsite power was restored.
The trip follows a fire earlier this week that affected non-safety-related equipment in unit 2. The NRC reported a transformer in the lower part of an inverter ignited in the plant vital battery room area at about 6:30 a.m. Monday. The fire was quickly put out with a fire extinguisher, and no emergency was declared.
The plant near Charlotte, S.C., is owned by Duke Energy, North Carolina Municipal Power Agency No. 1, North Carolina Electric Membership Corporation and the Piedmont Municipal Power Agency. It uses two 1,129 megawatt Westinghouse pressurized water reactors first licensed in the mid 1980s.