No health risk from Fukushima radiation

"Radiation exposure following the nuclear accident at Fukushima-Daiichi ... did not cause any immediate health effects," the UN Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) said.

"It is unlikely to be able to attribute any health effects in the future among the general public and the vast majority of workers for which dose histories have been assessed."

The committee, presenting after a meeting in Vienna the main findings of a report due to be published later this year, also praised the actions of the Japanese government immediately after the March 2011 disaster.

"The actions taken by the authorities to protect the public (evacuation and sheltering) significantly reduced the radiation exposures that would have otherwise been received by as much as a factor of 10," UNSCEAR said.

"No radiation-related deaths have been observed among nearly 25,000 workers involved at the accident site. Given the small number of highly exposed workers, it is unlikely that excess cases of thyroid cancer due to radiation exposure would be detectable in the years to come," it added.

The world's worst nuclear accident in 25 years was caused when a huge tsunami triggered by an earthquake hammered Japan's northeastern Pacific coast, sending multiple reactors at the decades-old nuclear power plant into meltdown.

The tsunami also crushed whole communities and some 19,000 people were killed by the natural disaster, but no one is officially recorded as having died as a direct result of the radiation that spewed from the crippled units in the following months.