The 966-megawatt V.C. Summer Nuclear Station, about 25 miles northwest of Columbia, began ramping up on December 17 and gradually reached full power December 21, said utility spokesman Robert Yanity.
The unit was shut down December 16 so workers could repair one of four valves that control the amount of steam turning the units turbine.
The shutdown was not considered an emergency.
South Carolina Electric & Gas Co., a principal subsidiary of SCANA Co., completed a nearly two-month-long scheduled refueling and maintenance outage December 10.