IAEA on Fukushima clean-up

Japan has been advised not to be overly conservative in its decontamination of areas affected by the Fukushima accident. Its work so far has been good but it should focus squarely on effective reduction of public radiation dose.

The advice comes from a team of 12 experts assembled by the International Atomic Energy Agency (IAEA) that has spent time with Japanese authorities over in the area marked for ‘deliberate evacuation’, northwest of the Fukushima Daiichi plant.

This is the area where most of the released radioisotopes came to ground, settling on the surfaces of buildings and into the first five centimetres of topsoil. Virtually everyone has left this 500 square kilometre area on advice from government, and they will not return until radiation doses from contaminants are assured to be less than 20 millisieverts per year.

The principle advice for the Japanese government was that it should “cautiously balance” the different factors that affect the net benefit of clean-up to ensure the actual reduction of radiation doses to the public. “They are advised to avoid over-conservatism which could not effectively contribute to the reduction of exposure rates.”

In practical terms this translates to focusing on the quickest dose reduction, without unwanted side effects like classifying millions of tonnes of very lightly contaminated topsoil as ‘radioactive waste’. It may be desirable to remove this soil from childrens’ playgrounds, for example, but some of the material may pose no realistic threat to health and could be recycled or used in construction work, said the IAEA team.

Courtesy of WNN
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