Features of exposure doses to the public due to the Fukushima accident

福島事故による住民への外部被ばくの特徴

斎藤 公明  

Saito, Kimiaki

According to trials for evaluating exposure doses to the public after the Fukushima accident, it has been made clear that doses from external exposures are more significant than those from internal exposures. The maximum external effective dose for the first 4 months after the accident was estimated to be 25 mSv by Fukushima prefecture. Additional external effective doses of Fukushima residents in recent years are evaluated to be all within a several mSv per year. It is expected that evacuees will not receive large additional external doses after they return to their home. The maximum thyroid dose due to inhalation of I in the early phase of the accident was estimated to be round 30 mSv by NIRS. Committed effective doses due to internal exposures from radiocesium intake have been evaluated to be notably smaller than 1 mSv as a whole. Further investigations to reduce the uncertainties in dose evaluation are urgent.