The Nuclear Safety and Security Commission has concluded that the power outage at the Gori-1 reactor on Feb. 9 had been caused by a combination of a worker’s mistake, a defect in the emergency diesel power generator and a weak safety culture. Korea Hydro and Nuclear Power Co., a state-run company that oversees the nation’s 21 nuclear reactors in operation, said the back-up power generator was checked a month ago but its failure to operate in an emergency suggests the test was perfunctory.
The accident highlights the issues raised with nuclear safety at nuclear power facilities. According to reports, the external power supply to the nuclear reactor while tests were run on the back-up diesel generators. The worker is reported to not have followed instructions, which led to problems with the air supply valve.
During the power loss that lasted for 12 minutes, the temperatures of the cooling water in the reactor went up from 36.9 to 58.3 degrees Celsius and the spent fuel storage tank from 21 to 21.5 degrees Celsius The air supply valve of the emergency diesel power generator at Gori-1 unit will be replaced with a new one and moveable diesel power generators will be placed.
After the blackout was reported, the leadership in charge attempted to cover up the incident, and not report it to upper management at KHNP. By law, nuclear accidents must be reported to the commission within 15 minutes.
“The chief of the Gori-1 unit entered the main control room during the power loss and decided not to report the accident to the KHNP and the NSSC in a meeting with senior staff after the power came back on,” the NSSC said in a press release. “According to related rules, the NSSC plans to press charges against those responsible for the delayed reports and omitting of records to cover up the accident.”
To conceal the power loss, the Gori-1 unit staff omitted it from the daily operation log. The event was only discovered after a Busan City Council member, who overheard a conversation between plant engineers at a restaurant, formally inquired what had happened.
“A chief engineeer and his colleagues had covered it up for more than a month,” NSSC chairman Kang Shang-Sun told a televised press conference. “They will be thoroughly held responsible, legally and administratively as well,” he said.
The Gori-1 reactor has had its 30-year life span recently extended despite questions about its safety, and is one of five reactors at the nuclear power plant in Busan that went online in 1978. The 35 year-old plant is the oldest nuclear plant in South Korea.
More needs to be done for global nuclear security: IAEA
The International Atomic Energy Agency (IAEA) said Wednesday that more needs to be done to improve the safety of nuclear and radioactive materials worldwide, citing security incidents which happened in recent years.
Khammar Mrabit, director of the IAEA’s Office of Nuclear Security, made the remarks at a press briefing at the UN nuclear watchdog’s headquarters in Vienna, ahead of next week’s Nuclear Security Summit in Seoul.
“Nuclear and other radioactive materials are still not properly secured. We have roughly around 200 incidents per year,” he said, adding that “continuous improvement is a must. Complacency is bad”.