From Asahi Shinbun (6/17/2012):
Minister of Reconstruction Tatsuo Hirano met with Mayor of Namie-machi Tamotsu Baba on June 17 in Nihonmatsu City in Fukushima Prefecture and discussed the decontamination effort. Minister Hirano reported to Mayor Baba the result of the model decontamination that showed what decontamination could do and could not do.
According to the result, by decontaminating a road [surface] for 2 and a half minutes the air radiation level would go down by one-third, but beyond that there was hardly any effect of decontamination. The reduction of radiation by wiping off the roofs and walls of a residence varied significantly, between 19 and 66 percent, and the conclusion was that "not much effect in reducing the radiation can be expected by repeating the same decontamination". After meeting with the Namie-machi Mayor, Mr. Hirano spoke with the press. He said, "Maybe the national government has given a wrong understanding [impression] that decontamination will instantly reduce (the annual cumulative radiation exposure) to less than 1 millisievert", admitting to the limit to what decontamination could do.
On the other hand, the long-term goal of decontamination policy of the national government "to aim for 1 millisievert [per year] and below" [of radiation exposure of the general public] would be maintained, Hirano said. As to how to achieve the goal, however, he didn't specify other than to say "We will develop new technologies."
What decontamination by the national government has achieved, other than giving a lot of contracts and money to the large national general construction companies? Not much, a government minister has finally admitted.
So far, the high-tech Japan's tools for decontamination have been:
- high-pressure washer
- screw driver
- broom and dustpan
- paper towel
- plastic bags
- blue tarp
New decon technologies? I think the most effective of all is "time".