100 tons of radioactive water leak at Fukushima plant

About 100 tons of highly radioactive water leaked from a storage tank at Japan's tsunami-stricken Fukushima Daiichi nuclear power plant, its operator Tokyo Electric Power Co. (TEPCO) said Thursday. A worker on patrol discovered water spilling from the tank's lid area late Wednesday, a TEPCO spokesman told a press conference, adding that the leak has been stopped and the tainted water did not reach the Pacific Ocean, which is 700 meters away. "As there is no drainage way near the leak, and the position is far from the sea, it is unlikely that the water has flowed into the ocean," he said. The tainted water flowed over a barrier surrounding the tank by passing through a rainwater drainage pipe, the spokesman said. The leak occurred because two valves in the pipes that transfer water from a decontamination system to storage tanks were mistakenly left open and another malfunctioned. The leaked water contains 230 million becquerels per liter of beta ray-emitting radioactive substances, consisting mainly of cancer-causing strontium 90, according to TEPCO. The latest leakage is one of the worst since August, when TEPCO said about 300 tons of radioactive water escaped from another tank, some of which is believed to have flowed into the ocean. The company is struggling to manage a massive amount of radioactive water used to cool the plant's three stricken reactors. The Fukushima plant, located 230 km north of Tokyo, was damaged by a 9. 0-magnitude earthquake and huge tsunami in March 2011, which resulted in the meltdown of three reactors and radiation leaks.