The nuclear reactor was shut down in early December 2012 for an emergency safety check following reports that many substandard parts were used under fake warranties in at least two reactors.

The NSSC earlier informed that a total of 13,794 substandard parts were supplied to the Korea Hydro & Nuclear Power for the past decade.

In addition, the safety commission noted that nearly 6,500 of them had actually been used in Younggwang 5 & 6 reactors.

The Nuclear Safety and Security Commission was quoted by Yonhap news agency as saying that, "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."

With the restart of the two 1 million kW reactors, the power supply is expected to significantly improve in South Korea.

As of now, the country operates 23 nuclear reactors that are supplying about 30% of the nation’s entire electricity consumption.