Assessment of population doses resulting from radioactive releases into the atmosphere-methodology

The assessment of the collective dose resulting from radioactive releases, required for the assessment of nuclear plant impact on man, is difficult on account of the complexity of the pathways. A method is presented as an example to assess in an average French region the collective doses resulting from continuous release of noble gases and iodine 131. An attempt is made to evaluate the variability of collective and individual doses, which are compared with the doses to the individuals of the more exposed group. Atmospheric concentrations are calculated from average diffusion conditions for French sites. Iodine-131 concentrations in milk used for the calculation of doses resulting from the ingestion of contaminated milk are assessed, taking account of the use of agricultural lands and marketing of the products. The doses from annual releases of 1Ci, differ by several orders of magnitude according to the various radionuclides. They should be weighted according to the isotopic compositions of releases from the various types of plants whose impact of the population is to be assessed