Preparation of radiological inputs for environmental impact assessment of routine normal operation of nuclear facilities

Abstract

The paper describes the input data generation for EIA (Environmental Impact Assessment) procedure based on the latest US EPA methodology for case of radioactive discharges from nuclear facilities to the living environment. Previous concept of numerical dose factors (or dose coefficient) for estimation of radiation doses due to exposure to radionuclides is in the EPA model extended to the numerical risk coefficients which enable alternative estimation of risk to health from exposure to radionuclides . The main characteristics of radiological situation around the source of pollution are computed on the basis of profound analysis of radionuclides propagation in atmosphere, hydrosphere and their further food-chain transport. The risk assessment is then done such a product of the risk coefficients and the main characteristics. A special software tool was developed and is presented here enabling to distinguish between short-term acute exposure scenarios and chronic long-term processes resulting in constant concentration (e. g. annually averaged) of a radionuclide in a given environmental medium. Particular attention was dedicated to ingestion pathway where dynamic models for computation of the annual activity intakes were customised to the local Czech conditions. Two cases of one-time radioactive fallout in a certain Julian day of a year (accidental releases) and long-term continuous submersion of ecosystem into the contaminated environment (normal releases during routine nuclear power plant (NPP) operation) are described by two different ingestion algorithms.