Radiation dose assessment data for external exposures from radioactive cesium in environment

Takahashi, Fumiaki  

JAEA has developed a radiation transport calculation code PHITS and Japanese adult models that enable us to perform computation dosimetry. In recent years, we have analyzed radiation dose assessment data by PHITS for public external exposure from radioactive cesium following the Fukushima Dai-ichi NPP accident. Here, a numerical method was developed to simulate transport of photons in environment and conversion coefficient data were analyzed to estimate effective dose for public including various ages. An integral dose assessment method was developed to predict radiation dose in future by taking account for cesium transfer and indoor dose reduction data were assessed by PHITS. In addition, the relationship between and effective dose and dosimeter reading was clarified for public exposure. These data were useful to make discussions on returning of habitants and to confirm verification of individual monitoring. These results and future plans on computational dosimetry are to be reported in this presentation.