Prognosis of thyroid doses in case of a maximum design basis accident at a nuclear power plant

The aim of this study was to make prognosis of thyroid doses in case of an accident at a nuclear power plant. In order to achieve this, the following was done: - assessment of thyroid doses formed due to maximum design basis accident (MDBA) at NPP with pressurized water reactor (at different distances from the station); - estimation of the length of the territories at which dose exposure may exceed the current international generic criteria for protective and other actions in case of a nuclear emergency. Various scenarios of possible weather conditions were considered in order to simulate the transfer of radionuclides in the atmosphere. This study allowed estimating the thyroid doses, as well as the necessity of protective and other actions in case of the MDBA. Results of prognosis using the international models have demonstrated that: - thyroid doses due to inhalation of iodine-131 don't exceed 2 mGy, due to consumption of contaminated milk - 40 mGy, vegetables - 5 mGy; - there is no need in thyroid blocking for population; The results of modeling performed in this study form a basis for developing national arrangements for response to a MDBA at considered NPP. (authors)