South Korea widens nuclear investigation, risks power cuts By Meeyoung Cho SEOUL (Reuters) - South Korea's main nuclear power supervisor extended an investigation into forged safety certificates for reactor components to three more facilities on Tuesday, a day after shutting down two reactors. South Korea generates 30 percent of its electricity from 23 nuclear reactors at state-owned plants, and the government warned of the potential for unprecedented power shortages as the shutdowns eat into the country's thin spare capacity. Authorities were at pains to stress that the parts involved related to non-crucial aspects of the plants' operation and posed no risk to safety. Yet in the aftermath of the Fukushima nuclear accident in Japan, there were concerns the discovery could tarnish the image of the country's nuclear program. The commission will verify all the components at the reactors by setting up a private and public team ... We will make regulations to supervise them," said one of the nine members of the Nuclear Safety and Security Commission, who could not be named as he was not authorized to speak to the media. A spokesman at the commission added that members of the private and public joint team would be announced on Wednesday at the earliest, along with their investigation schedules. The three additional reactors under investigation are still running. The two reactors already shut down will remain closed until the parts are replaced. With another five reactors already closed for regular maintenance and glitches, a total of 6,500 megawatts of power capacity has been removed from the grid, from a total capacity of 81,740 MW. The two shut reactors, each able to supply 1,000 MW, were found to have components with certificates purportedly from U.S. and Canadian regulators that had been forged by the suppliers of the parts. The latest incident comes after a series of problems in South Korea's nuclear power sector this year. Several reactors have been shut down for varying periods for malfunctioning, and officials at state-owned Korea Hydro & Nuclear Power (KHNP) have been investigated for receiving bribes, according to local media. There were a lot of glitches earlier this year in reactors management. Those in charge of the matter often said they didn't know, but not knowing is also a problem," said Kim Jin-woo, president and chief executive of Korea Energy Economics Institute, a government think-tank for energy policy. KHNP, fully owned by state-run utility Korea Electric Power Corp (KEPCO), reported eight firms that supplied parts had forged 60 certificates to cover 7,682 items between 2003 and 2012, the ministry and the company officials said. KHNP declined to identify the eight firms. Local media reported on Tuesday that KEPCO President and Chief Executive Kim Joong-kyum would soon tender his resignation, although the reports did not say why. A KEPCO spokesman said on Tuesday that he had no knowledge of the matter. Government officials said South Korea would take measures to cut power consumption rather than hiking imports of alternative fuels to feed additional electricity generation. "We will not increase our purchases of LNG and coal compared with what we have usually bought for the peak winter demand," said an official at the Ministry of the Knowledge Economy, adding that most power plants were operating at full capacity anyway. We will control demand. We are holding meetings to detail the control measures. South Korea generates 40 percent of its 81,740 megawatts of power with coal, 30 percent with nuclear and the remainder with liquefied natural gas (LNG), according to government data. Actual spare capacity in the peak winter demand months of January and February could fall to just over half the safety margin that the government aims to keep to guarantee supplies. With little spare capacity, the grid would be strained and vulnerable to power outages. The government aims to maintain 4,500 megawatts of reserve power generation capacity over projected demand, officials said. Excess capacity is expected to be 2,750-5,400 megawatts in November and December, and could fall to 2,300 megawatts in January and February, according to the government forecast on Monday. South Korea, which experienced nationwide power cuts in September of last year, has been campaigning to encourage consumers to save energy in the peak seasons of summer and winter. Authorities imposed fines on public buildings that kept doors open while running air conditioning this summer and stipulated that thermostats in big department stores and hotels be set at 26 degrees Celsius, several degrees higher than usual. It has also built up fuel supplies that could be deployed during an emergency through such measures as filling up LNG storage. Reporting by Meeyoung Cho; Additional reporting by Eunhye Shin and Jumin Park; Editing by Raju Gopalakrishnan and Simon Webb