Japanese government on alert as Fukushima leaks radiation

Japan’s government is on maximum alert over the Fukushima nuclear plant where highly radioactive water has halted repair work and plutonium has been found in the soil. Small amounts of radiation have spread across Asia.

Reuters/Christian Slund/Greenpeace

Prime Minister Naoto Kan conceded that the situation at the coastal atomic power station, which has leaked radiation into the sea, remained "unpredictable" and pledged his government would "tackle the problem while in a state of maximum alert".

Emergency crews have used fire engines and pumps to pour thousands of tons of water onto reactors where fuel rods are thought to have partially melted. They have also topped up pools for spent fuel rods.

But the run-off is now making it too dangerous for workers to go near several of the reactor buildings to repair the cooling systems needed to stabilise the plant.

For now they have no choice but to keep pumping water into the stricken reactors, top government spokesperson Yukio Edano said Tuesday.

If the rods are fully exposed to the air, experts fear that they would rapidly heat up, melt down and spew out far greater plumes of radiation at the site, which is 250 kilometres north-east of Tokyo.

The water out of reactor two has measured 1,000 millisieverts per hour - four times the recently-raised total exposure limit for emergency staff, and a level that can cause radiation sickness with nausea and vomiting in an hour.

The immediate challenge is to safely dispose of the massive amounts of contaminated water.

The plant’s operator Tokyo Electric Power Co (Tepco) said Tuesday that plutonium had been detected in soil samples that were taken a week ago at five spots in the plant. But the company says that it believes there is not enough to harm human health.

The US environmental protection agency says internal exposure to plutonium "is an extremely serious health hazard" as it stays in the body for decades, exposing organs and tissue to radiation and increasing the risk of cancer.

Tepco shares plunged 18.67 per cent on Tuesday, and have now lost nearly three quarters of their pre-crisis value. The government is reported to be considering taking a majority stake in the power company.

The governments of China, South Korea, the Philippines and Vietnam have reported that radiation has drifted over their territories, while saying that the levels are so low that there is not health risk.

Rainwater in the US state of Ohio was found to have been contaminated on Monday.