The Nuclear Regulation Authority has drafted a proposal to accelerate the return home of Fukushima nuclear disaster evacuees by using radiation readings that tend to be lower than the ones now officially used.
The NRA wants residents to take radiation measurements with dosimeters instead of relying on the current government system of determining levels through aircraft monitoring.
The proposal does not seek a change in the long-term goal of reducing accumulated radiation exposure in affected communities to 1 millisievert a year.
But the government’s air dose rate has often been three to seven times higher than exposure levels checked by individual residents with dosimeters, according to a survey conducted by municipalities in Fukushima Prefecture.
Given the same 1 millisievert target, radiation levels based on dosimeter readings could effectively become a more relaxed target than that based on the air dose rates.
The current dose rates are based on the assumption that people will spend eight hours a day outdoors and 16 hours indoors.
Since September, at the request of the government's Nuclear Emergency Response Headquarters, a team consisting of NRA members and outside experts has discussed “scientific and technical aspects” of a basic direction regarding the return home of evacuees.
At a June meeting following decontamination work in Tamura, Fukushima Prefecture, the central government suggested that residents check radiation exposure levels by themselves with dosimeters.
The NRA urged the government to continue the decontamination work to further reduce radiation levels, saying that giving residents an option to choose the timing of their return home is its responsibility.
But the NRA’s draft proposal, to be announced on Nov. 11, does not refer to impact on evacuees’ health and measures that should be taken. An NRA official also confirmed that it never used the word “safe” in discussions.
The NRA proposal recommends having “communicators” explain to residents about acceptable levels of radiation to eliminate their anxieties.
Under international standards, an annual radiation dose of 1 to 20 millisieverts is acceptable.
Based on those standards, the Japanese government plans to bring annual radiation doses in heavily contaminated areas to within 20 millisieverts to allow residents to return, and eventually to “1 millisievert or less” as a long-term goal.
The government has already spent billions of yen on decontamination work in municipalities affected by the nuclear disaster.
But some evacuees have raised concerns about returning to areas that have not achieved the 1-millisievert goal.
Some members of the ruling Liberal Democratic Party have requested a review of the 1-millisievert long-term goal. In addition, the government has sought to have the individual dose limit eased with the endorsement of the NRA to encourage residents to return to their homes.
The NRA agreed to change the calculation method of radiation doses from an estimate based on aircraft monitoring to individual measurements with dosimeters.
(This article was written by Yuri Oiwa and Ryuta Koike.)
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