South Korea on Friday resumed operation of a nuclear reactor recently shut down due to problems detected in its electric generator, plant operators said.

The reactor at Gori Nuclear Power Plant in Ulsan, 410 kilometers southeast of Seoul, was expected to reach its full output early Saturday, following its resumption of operation at 5:50 a.m. Friday, according to the Korea Hydro & Nuclear Power Co.

The state-run nuclear plant operator had to shut down the reactor with a capacity of 950,000 kilowatts Wednesday due to problems with the generator attached to the reactor.

The shutdown, along with an earlier interruption of operation of another reactor at a nearby plant in Uljin, 330 kilometers southeast of Seoul, had created a near panic amid fast rising demand during the winter peak season.

The two reactors generate 1.95 million kilowatts of electricity, nearly half of 4 million kilowatts the country needs to maintain a safe level of reserve supplies. The Uljin reactor resumed operation Thursday after its interruption was found to have been caused by what commerce minister Hong Suk-woo called a “mistake” by an unexperienced engineer.

South Korea currently has 21 nuclear reactors, supplying about 40 percent of the country’s total electricity needs. (Yonhap News)