Distribution map of natural gamma-ray dose rates for studies of the additional exposure dose after the Fukushima Dai-ichi Nuclear Power Station accident

福島第一原子力発電所事故後の追加被ばく線量評価のための天然放射線分布

眞田 幸尚   ; 吉村 和也  ; 卜部 嘉*; 岩井 毅行*; Katengeza, E. W.*

Sanada, Yukihisa; Yoshimura, Kazuya; Urabe, Yoshimi*; Iwai, Takeyuki*; Katengeza, E. W.*

The information on the absorbed dose rate which is derived from natural radionuclides needs to evaluate additional exposure dose around Fukushima Daiichi Nuclear Power Station. However, there are not enough position resolution and precision for data for this evaluation. In this study, we created the map of the absorbed dose rate which is derived from natural radionuclides based on several airborne radiation monitoring data. The created map was made sure to have sufficient reliable accuracy by comparing with the many in-situ measurement on the ground. These data were applied to discriminate the absorbed dose rate of background from an actual periodic dose rate survey results as an application study. Evaluation results for the distribution of absorbed dose rate of background are expected to contribute to the summarization of international studies of the FDNPS accident.