External exposure of public to radionuclides deposited in the terrestrial environments after the accident at the Fukushima Daiichi Nuclear Power Station; The UNSCEAR Model 2020

Ulanowski, A.*; Balonov, M.*; Chipiga, L.*; 木名瀬 栄

no journal, , 

For the UNSCEAR 2020/2021 Report vol. II, the dynamics model of ambient dose rates and the long-term forecasts of external exposures in Japan has been critically reviewed and further developed, using results of extensive systematic radiation monitoring in various environments and population-based studies with personal dosimeters. The new model follows the generic framework compatible to existing approaches, while considering country-specific features important for the public dose assessment. The model has been applied for forecasting external doses and their uncertainties due to unknown future trends of dose rate dynamics or population behaviour. It is demonstrated that uncertainties of the dose rate trends may lead to substantial uncertainties of the estimated cumulative external doses, especially, for evacuated members of the public returning to their homes, due to countermeasures or remedial actions.