Areas surrounding Japan's crippled Fukushima nuclear plant could remain uninhabitable for decades due to high radiation, the government warned on Saturday as it struggles to clean up after the world's worst nuclear disaster since Chernobyl.

日本政府上周六警告称，被废弃的福岛核电站周围地区由于高辐射，可能几十年内都无法居住。福岛核事故是切尔诺贝利核事故来最严重的一起，日本政府一直尽力清除放射性物质。

Japan faces the daunting¹ task of decontaminating large areas of land around the Fukushima Daiichi nuclear complex, which is still leaking low levels of radiation nearly six months after an earthquake and tsunami² triggered a nuclear meltdown.

In a meeting with local officials on Saturday, the government estimated it could take more than 20 years before residents could safely return to areas with current radiation readings of 200 millisieverts per year, and a decade for areas at 100 millisieverts per year.

The estimates, which merely confirm what many experts have been saying for months, are based on the natural decline of radiation over time and do not account for the impact of decontamination（净化） steps such as removing affected³ soil.

An vast area is still uninhabitable around the Chernobyl plant 25 years after that disaster.

The Japanese government unveiled guidelines last week with the aim of halving⁴ radiation in problem areas in two years, but for spots with very high readings it could take much longer to reach safe levels.

Japan has banned people from entering within 20 km (12 miles) of the Fukushima plant, located 240 km northeast of Tokyo. Around 80,000 people have been evacuated⁵ since the March 11 quake and tsunami and many are living in shelters or temporary homes.

The government's announcement follows the release of data last week showing radiation readings in 35 spots in the evacuation zone above the 20 millisieverts per year level deemed safe by the government. The highest reading was 508 millisieverts in the town of Okuma, about 3 km from the nuclear plant.

Kan, who resigned on Friday as leader of the ruling Democratic Party of Japan amid intense criticism of his handling of the nuclear crisis, also told Sato that the government planned to build a temporary storage facility in Fukushima for radioactive waste.

The accident at the Fukushima plant is likely to have released about 15 percent of the radiation released at Chernobyl in 1986, Japan's Nuclear and Industrial Safety Agency has estimated.

But that is still more than seven times the amount of radiation produced by Three Mile Island accident in the United States in 1979, and experts have estimated Japan's decontamination efforts could cost as much as 10 trillion yen⁶ ($130 billion).