JAPAN HAS revealed that the clean-up of land irradiated by the Fukushima nuclear disaster could stretch to an area larger than greater Tokyo.

Removing topsoil containing caesium and other contaminants is likely to leave a pile of nuclear waste almost 29 million cubic metres high – enough to fill one of the city’s largest stadiums 80 times, says a government report released this week.

The March 11th earthquake and tsunami triggered a triple meltdown and a series of explosions at the Fukushima Daiichi Nuclear Power Plant that showered the surrounding prefectures with radioactive materials.

Decontamination work from the world’s worst nuclear accident in 25 years could extend to a 2,400sq km (930sq miles) zone across the four worst affected prefectures, according to the environment ministry report, the first official assessment.

That’s an area roughly the size of Co Wexford.

Experts have advised the government that about 5cm of topsoil would have to be excavated to make the land safe. The laborious decontamination process will also involve removing leaves and dirt from woodland, which covers 60-70 per cent of the affected area.

More than 80,000 people have been evacuated from a 20km radius of the crippled nuclear plant and the most heavily irradiated towns and villages nearby. But radioactivity in cities up to 60km from the plant has exerted serious strain on local life there.

Operator Tokyo Electric Power Co (Tepco) said yesterday that temperatures in all three of the disabled reactors had fallen below boiling point for the first time since the crisis began. But the utility added that it would not declare cold shutdown – meaning the plant’s uranium fuel has been permanently cooled and made safe – until it stops emitting radiation.

Radioactive hotspots in some highly populated areas exceed those found in Chernobyl, scene of the 1986 nuclear disaster. The environment ministry is focusing its decontamination on areas where radiation exposure is more than 5 millisieverts a year, roughly double UN estimates for safe background radiation.

Minister for the environment Goshi Hosono faces fierce resistance from local officials in Fukushima to a tentative plan to temporarily store the radioactive waste in the prefecture while the government looks for a permanent home for it.

Last month Mr Hosono said the entire country must share Fukushima’s plight by hosting the waste. But as yet no local authority has stepped forward.

A budget of $2.9 billion has already been allocated for the clean-up, but the environment ministry has asked for another 450 billion yen for this fiscal year alone, according to Kyodo News.

The issue of compensation for evacuees has also become an increasingly vexed issue.

Tepco has been flooded with angry calls since announcing this month that the now homeless evacuees will have to fill in a 60-page application form before their claims can be processed.