A new leak of 100 tons of highly radioactive water has been discovered at Fukushima, the plant's operator said Thursday, after it revealed only one of nine thermometers in a crippled reactor was still working.
The toxic water is no longer escaping from a storage tank on the site, said a spokesman for Tokyo Electric Power Co (TEPCO), adding it was likely contained, but the news is a further blow to the company's already-battered reputation for safety.
"As there is no drainage way near the leak, which is in any case far from the ocean, it is unlikely that the water has made its way into the sea," he said.
The tank, one of hundreds at the site that are used to store water contaminated during the process of cooling broken reactors, sits around 700 meters from the shore.
The water it contains is highly radioactive, with a beta radiation reading "at 230 million becquerel per liter," he said.
That contamination level compares with government limits of 100 becquerels per kilogram in food and 10 becquerels per liter in drinking water. A becquerel is a unit of radioactivity.
Beta radiation, including from cancer-causing strontium-90, is potentially very harmful to humans and can cause damage to DNA. But it is relatively easy to guard against and cannot penetrate a thin sheet of aluminium.
"We are now in the process of recovering the leaked water and the earth it has contaminated," the spokesman added.
The tank holds water filtered to remove cesium but which still contains strontium, a substance that accumulates in bones and can cause cancer if consumed.
About half of the beta radiation from the latest leak is thought to be strontium-90, TEPCO said, meaning its concentration level is nearly four million times the legal limit of 30 becquerels per liter.© (c) 2014 AFP