Radioecological assessment of reactor facilities based on postulated emergency scenarios

The methodical approach based on scenarios of design and beyond design basis accidents was developed for comparative radioecological assessment of reactor facilities. The dynamics of possible radiation doses to the thyroid and the whole body of the public resided nearby the Russian nuclear power plants equipped with the VVER-440, VVER-1000, VVER-1200 and BN-800 reactors was estimated. With the use of the conservative approach for each accident scenario, as well as with the use of acute and medium-term dose criteria, radiation exposure indices were calculated for each accident scenario. Reactor facilities are ranked according to an index summarizing the accident scenarios features and the probability of their realization, the height of radioactive emissions and the activity of dosage-forming radionuclides. The potential radioecological danger of Russian reactors to the population has been reduced. The lowest estimates of the summarized emergency risk are typical for the advanced VVER-1200 reactor of the 3+ generation and the fast neutron reactor BN-800. The most severe emergency scenarios for each considered reactor are highlighted. The VVER-440 reactor has the highest number of severe projected accidents exceeding the dosage criteria envisaging evacuation of the population. The directions of further research related to the analysis of the environmental radiological effects, the justification of radiation protection measures and the development of operational intervention levels in the acute post-accident period are outlined.