Microscopic cracks have been found in six tunnels that guide control rods in a 1,000 MW reactor at the Yonggwang nuclear power plant in South Korea.
According to Reuters, the reactor where the cracks were found was offline for maintenance and will remain offline until the source of the problem is found. Workers with Korean Hydro and Nuclear Power Co. (KHNP) found the cracks just two days after the plant was forced to shut down to replace parts that had been provided with forged certificates, the article said.
The problem was discovered while the reactor was switched off for a regular 36-day maintenance period. But it will now stay out of service for a further 47 days as inspectors seek to determine the cause of the cracks, the South Korean Nuclear Safety and Security Commission said.
“There are cracks in six tunnels. The reactor has been halted since October 18 for regular maintenance and now the process has been extended by a further 47 days for repair of the cracks,” a spokeswoman with the presidential Korea Nuclear Safety and Security Commission said.
South Korea must now investigate all 23 nuclear reactors after thousands of parts were supplied with forged safety documents.
The Yonggwang Nuclear Power Complex has six units of three types. Units No. 1 and No. 2 are Westinghouse pressurized light water reactors. Units No. 3 and No. 4 are CE System 80 (2-loop) steam supply system pressurized water reactors. No. 5 and No. 6 are based on the design of the Ulchin-3 reactor, which was the first Korean Standard Nuclear Power Plant, with several updates and modifications.