Forty-five tons of radioactive water leaked from a processing facility at the Fukushima No. 1 nuclear power plant and some has likely entered the sea, Tokyo Electric Power Co. officials said on Dec. 4.
Forty-five tons of radioactive water leaked from a processing facility at the Fukushima No. 1 nuclear power plant and some has likely entered the sea, Tokyo Electric Power Co. officials said on Dec. 4.Although the water was processed after becoming highly contaminated when it was used to cool the damaged reactors, it still contains radioactive materials at a concentration level much higher than permissible standards, they said.An estimated 220 tons of water has leaked from the processing facility, including the 45 tons, the officials said.The water is used in a recycling system that pumps water into the reactors to keep them submerged and cool. It is then purified and again pumped into the reactors.The cesium level per liter of the leaked water was 45,000 becquerels, about 300 times higher than permissible standards in seawater under the law for regulation of nuclear reactors and related facilities.According to an analysis of data collected so far, the concentration level for strontium was estimated at around 100 million becquerels, or 1 million times higher than permissible standards. But TEPCO officials said that was just an estimate, and that more time is needed to ensure accuracy.Operations of the processing facility were suspended because of the leak. However, more than 10,000 tons of processed water is stored in tanks, giving TEPCO enough water to continue the cooling process of the reactors, the company said."There will be no (adverse) influence on the cold shutdown schedule," a TEPCO official said.The utility and the government said they expect to achieve a stable state of cold shutdown at the stricken plant before the end of the year.A worker of a subcontractor found the leak around 11:30 a.m. on Dec. 4, TEPCO officials said. The water had accumulated around a device in the processing system and was leaking through a crack near the floor into a gutter, which leads to the sea about 500 meters away. TEPCO stopped the leakage with sandbags.The company checked the cesium levels in the sea and found a concentration of 31 becquerels per liter of water, about the same as or slightly higher than the level shown in recent monitoring of the seawater.According to TEPCO officials, the leaked water contains a "middle-level" concentration of radioactive substances, which is higher than the "lower-level" water discharged into the sea in April.The radiation level on the surface of the leaked water was 110 millisieverts per hour in terms of beta particles and 1.8 millisieverts for gamma particles. Beta particles are created from certain substances, including strontium, that could lead to exposure to radiation in human bodies, while gamma particles come from substances that include cesium and can penetrate the body more easily.