South Korea on Wednesday restarted the operation of a nuclear reactor that was shut down early last month for an emergency safety check following reports that thousands of substandard parts had been used under fake warranties in at least two reactors.

The Younggwang 6 reactor resumed operation earlier in the day after the Nuclear Safety and Security Commission approved its restart on Monday.

The safety commission earlier said a total of 13,794 substandard parts had been supplied to the Korea Hydro & Nuclear Power Co. for the past decade and that 6,494 of them had actually been used in Younggwang 5 and Younggwang 6 reactors.

“All the parts that had been supplied under fake warranties have been replaced and all safety checks needed for a restart of the reactors have been completed,” the safety commission said in a released statement.

The Younggwang 5 reactor was restarted following the safety commission’s approval on Monday, but the Younggwang 6 reactor had required additional safety checks as it has also been undergoing a period of regular maintenance.

The restart of the two 1-million kilowatt reactors is expected to greatly improve the country’s power supply. (Yonhap News)