Generic Models And Parameters For Assessing The Environmental Transfer Of Radionuclides From Routine Releases

Describes an approach for assessing doses to members of the public as part of an environmental impact analysis of predictive radioactive discharges. This is achieved by using screening models which describe environmental processes in mathematical terms, producing a quantitative result.

This handbook provides generic parameter values for estimating the transfer of radionuclides from environmental media to wildlife for the purpose of assessing potential radiation exposure under equilibrium conditions. These data are intended for use where site specific data are either not available or not required, and to parameterize generic assessment models. They are based on a comprehensive review of the available literature, including many Russian language publications that have not previously been available in English. The publication addresses the limitations of the parameter values and the applicability of data. Some general background information on the assessment of potential impacts of radioactive releases on wildlife is also included. It complements the existing handbook in the same IAEA series with parameter to assess the radiological impact to humans.

This publication provides the results from Working Group 1, on Reference Methodologies for Controlling Discharges of Routine Releases, of the IAEA's EMRAS II (Environmental Modelling for Radiation Safety) programme, which ran from 2009 to 2011. This Working Group carried out an intercomparison of methods used for assessing radiological impacts to people and the environment due to authorized releases of radionuclides during normal operation of nuclear facilities. Three important types of exposure scenarios were considered, those related to atmospheric, marine and river releases. The publication describes the details of the hypothetical radioactive release scenarios, the environmental pathways considered, the environmental transfer models applied, the calculation methods and the results obtained. An analysis of the results and the main findings and conclusions relevant for the use of the described input data and methodologies in regulatory applications is included. The publication also presents considerations on selection of the 'representative person' and a summary of the different approaches in some States for the regulatory control of radioactive discharges. Input data is included in the annex.

Assessment of the radiological impact of planned or existing practices involving the (actual or potential) release of radionuclides to the environment are largely based on the use of modelling techniques which allow prediction of the relationship between environmental levels and releases and the associated radiation dose to man. Models are imperfect means of representing environmental transfer processes, and it is essential to know the reliability which can be associated with the predictions of these models for each and every assessment situation. Such information is necessary in order to establish confidence in model predictions and, in particular, to allow adequate safety margins to be set in the design of nuclear facilities. This knowledge is also a prerequisite to determine release limits or to decide whether further research is justified in order to improve predictive accuracy. Therefore a number of distinguished pilpers have been presented during this workshop which focused both on practical aspects of variability of observations of facts occuring in nature, but also on learned aspects of the science of statistics. It is not very clear, however, whether much insight in mechanisms is gained by such an approach. This insight is probably rather reached by a straightforward judgment of the quality of the primary data and by the willingness to think over carefully the experiments and measurernents before doing them. The book is composed such as to give the reader the chance to quietly study the presented papers in good order.