The state-run operator of nuclear power plants has resumed the operation of South Korea\'s oldest nuclear reactor after a regular maintenance, an official said Sunday. The resumption of the 587,000 kilowatt reactor on Saturday came six months after the Korea Hydro and Nuclear Power inspected equipment and replaced facilities at the Kori reactor 1 in the area of the same name, about 410 kilometers southeast of Seoul, said Choi Yong-jin, an official of the Korea Hydro and Nuclear Power. The reactor, which started its commercial operation in 1978, is the oldest one in South Korea. Kori, a sea-front area in South Korea\'s second-largest city of Busan, is home to four out of South Korea\'s 23 nuclear reactors that supply about 30 percent of the country\'s total electricity consumption. Currently, six out of the 23 reactors are currently offline due mainly to a scheduled maintenance or work to replace the substandard parts, Choi said.