Uncertainties in the assessment of the radiation impact on biota in the vicinity of nuclear facilities

Evaluation of radiation impact on biota inhabiting near nuclear facilities of radioactive release to atmosphere from reactors of different types (WWER-1200, BN-600, BN-800, UVV-2M) is considered in the paper. Radiation dose rates to reference groups of terrestrial biota species (annelids, insects, large and small mammals, grasses and conifers) vary from 0.01 to 0.2 µGy/day. The impact of the NPP using up-to-date reactor WWER-1200 is shown to be not exceeding 1% of the total radiation impact. To compare correctly radiation impacts on the biota species from radioactive release and from exposure to established radiation dose rate limits, it is necessary to take into account contribution of all constituents of radiation background. Impacts on biota species from the total exposure to radioactive release or the exposure to established radiation dose rate limits were evaluated. Estimated radiation impact from exposure to the radioactive release did not exceed 0.1; the impact from the established dose rate limits was 0.9. Obtained information allows making the following conclusion: uncertainty of quantitative evaluation of radiation impact on biota in planned radiation situations is mainly caused by uncertainty of established dose rate limits. There is a need to establish dose criteria for emergency, it will allow creating “weighty” radioecologic justification of “nuclear power plants with account for potential emergency conditions.