SEOUL, April 14 (Reuters) - South Korea's oldest nuclear reactor has been shut down due to a glitch in the plant's electric circuits, an official said on Thursday, amid rising concerns about nuclear safety after Japan's nuclear crisis.
There were no radiation leaks from the plant on the peninsula's southeast coast, the operator said.
Reactor One at the Kori nuclear power plant, which began operation in 1978, has been down since Tuesday when the electric circuit malfunction was discovered and repairs will likely continue through Friday, the power plant official said, asking not be named.
"The problem is at the system that supplies electricity to the power plant," the official said. "It would be wrong to say there is a problem to the reactor."
The Kori reactor has been in operation past its initially intended 30-year life but has undergone extensive renovation to extend its use by another decade through 2017, local media said.
Concerns about radiation fallout from Japan's nuclear disaster have kept South Korea on edge about whether radioactive material could reach the country about 1,000 km from the site of the crippled nuclear plant in Fukushima.
It also raised concerns about the safety of its 21 nuclear reactors at the four plants in operation in South Korea, which span in age from 33 years to less than three months.
Some regions of South Korea are prone to earthquakes but none greater than magnitude 4.0 have been reported for decades and officials say all its reactors have been built to resist damage from natural disasters possible in the country.
Officials said there was no change to its policy of expanding nuclear energy use, and 11 new reactors are under construction or being planned.
South Korea's nuclear power plants supply about 24 percent of the country's electricity supply and are operated by Korea Hydro & Nuclear Power Co., a wholly owned subsidiary of state-run KEPCO .
South Korea has expressed concerns about Japan's handling of the crisis, accusing Tokyo of incompetence for failing to notify Seoul it would pump radioactive water into the sea.
Seoul wants to send a team of its own experts to inspect the plant, but Japan has refused. Nuclear experts from the two countries met in Japan this week, but failed to agree on a visit, Yonhap news agency said.
South Korea and China agreed on Wednesday during a meeting in Beijing to cooperate on nuclear safety and ensure swift exchange of information in the event of emergency situations at either country's nuclear sites. (Reporting by Jack Kim; Editing by Jeremy Laurence and Sugita Katyal)