South Korea's nuclear safety commission on Friday approved restarting a nuclear reactor that was shut down last week due to what has been determined as a technical problem in one of its control cards.

"The investigation confirmed a control card that regulates the level of output of the reactor had been damaged, triggering the safety shutdown system that halted the reactor's operation," the Nuclear Safety and Security Commission said in a press release.

The reactor at Wolseong Nuclear Power Plant, located some 400 kilometers southeast of Seoul, stopped operating at 6:50 a.m. last Saturday.

The commission said the damaged control card has been replaced with all other 13 control cards also checked for any damages. (Yonhap)