Highly contaminated water leaked from yet another storage tank at Japan’s devastated Fukushima nuclear plant, Tokyo Electric Power Co said on Thursday.
“Some of the water could have flowed into the sea through a ditch nearby,” said Hiroki Kawamata, a spokesman for Tokyo Electric, the operator of the Fukushima Daiichi Nuclear Power Station.
An estimated 430 litres of radiation-contaminated water leaked and the operator detected 200,000 becquerels per litre of beta ray-emitting radioactive substances including strontium 90, far above the legal limit of 30 becquerels per litre, Mr Kawamata said.
Tokyo Electric found the leak on Wednesday night and it was attributed to the overfilling of the tank built on a slope, he said. The tank is made of steel sheets joined by bolts, the same kind as the one from which about 300 tons of highly-contaminated water escaped in August, some of which may have flowed into the sea, the operator said.
Later that month, the Nuclear Regulation Authority raised the severity of the leak on the International Nuclear Event Scale to level 3 — denoting a “serious incident.” Of some 1,000 storage tanks that have been built in the complex, about 350 are of the same type that was discovered leaking this week, Mr Kawamata said.
The tanks are used to contain large amounts of contaminated water from three reactors that suffered meltdowns after the plant was hit by the March 2011 earthquake and tsunami.