South Korea investigates nuclear reactor malfunction

South Korea is investigating the problem that caused a nuclear reactor, located 330 kilometres southeast of Seoul in Uljin, to abruptly halt early Wednesday morning.A (Yonhap) news agency report, quoting Korean officials, said the reactor stopped working due to an unusual signal, but there was no immediate danger of a radiation leak.The Reactor Unit 5 at the Hanul Nuclear Power Plant halted operation at 4:17 am after a warning signal came on, according to officials from the Korea Hydro & Nuclear Power Company.An investigation is currently under way to identify the exact problem. Four reactors, including Hanul, are currently out of operation.South Korea currently operates 23 nuclear reactors that supply about 30 percent of its total electricity consumption, Yonhap said.