December 10, 2013
Wrecked Fukushima storage tank leaking highly radioactive water
Contaminated water with dangerously high levels of radiation is leaking from a storage tank at Japan's crippled Fukushima nuclear plant, the most serious setback to the clean up of the worst nuclear accident since Chernobyl.
The storage tank breach of about 300 tonnes of water is separate from contaminated water leaks reported in recent weeks, plant operator Tokyo Electric Power Co said.
The latest leak is so contaminated that a person standing half a metre (1 ft 8 inches) away would, within an hour, receive a radiation dose five times the average annual global limit for nuclear workers.
After 10 hours, a worker in that proximity to the leak would develop radiation sickness with symptoms including nausea and a drop in white blood cells.
"That is a huge amount of radiation. The situation is getting worse," said Michiaki Furukawa, who is professor emeritus at Nagoya University and a nuclear chemist.
The embattled utility Tokyo Electric has struggled to keep the Fukushima site under control since an earthquake and tsunami caused three reactor meltdowns in March 2011.
Japan's Nuclear Regulation Authority has classified the latest leak as a level 1 incident, the second lowest on an international scale for radiological releases, a spokesman said.
It is the first time Japan has issued a so-called INES rating for Fukushima since the meltdowns. Following the quake and tsunami, Fukushima was assigned the highest rating of 7, when it was hit by explosions after a loss of power and cooling.
A Tokyo Electric official said workers who were monitoring storage tanks appeared to have failed to detect the leak of water, which pooled up around the tank.
"We failed to discover the leak at an early stage and we need to review not only the tanks but also our monitoring system," he said.
Tokyo Electric, also known as Tepco, said it did not believe water from the latest leak had reached the Pacific Ocean, about 500 metres (550 yards) away.
Nonetheless, continued leaks have alarmed Japan's neighbours South Korea and China.