South Carolina's V.C. Summer nuclear plant tripped offline Tuesday as it was powering up.
The plant had reached 48 percent power when a condensate bypass valve failed to open, according to a report filed with the Nuclear Regulatory Commission. Operators at the time were in the process of removing the condensate polishing system from service. When the valve failed, it caused the water level to drop in a deaerator storage tank, tripping feedwater pumps. According to the NRC, water in a steam generator then fell to a level actuating safety systems that shut down the reactor and started emergency feedwater pumps. Water levels recovered quickly, and the shutdown was uncomplicated.
V.C. Summer's Westinghouse three-loop pressurized water reactor re-entered service May 31 following a scheduled refueling outage. South Carolina media reported that it then shut down voluntarily July 13 to repair a leaking relief valve. The unit had restarted and reached 2 percent power as of Wednesday morning, according to the NRC.