An assessment methodology of environmental risks associated with radioactive waste management

One of the major environmental concerns associated with the projected increase in nuclear power generation is the treatment and storage or disposal of radioactive wastes. The U.S. Environmental Protection Agency (EPA) in collaboration with the University of New Mexico has been developing a detailed assessment methodology of both the short-term as well as long-term quantitative risks on the environment resulting from the release of radionuclides during all phases of radioactive waste management operations. This past year a comprehensive model has been developed for the public health and environmental impacts from the disposal of high-level and transuranic waste in geological formations. Parametric studies have been performed with this model for various geological disposal media and for waste in different forms. EPA has planned to utilize these parametric risk calculations to translate probabilities and consequences of risk occurrences into a cost-effectiveness perspective for decision-making purposes. This comprehensive model has consisted of a release or fault tree model, an environmental model, and an economic model. Fault trees have been constructed to provide the relationships between various geophysical, meteorological, and man-caused events which are potential mechanisms for release of radioactive material to the environment from waste repositories. The environmental model includes the transport to and accumulations at various receptors in the biosphere, including a determination of pathways from environmental input concentrations to radiation dose to man. Finally, the economic results are used to compare and assess the various disposal concepts as a basis for formulating policy decisions. Implementation of this assessment methodology is possible for a whole range of both radioactive as well as non-radioactive hazardous materials which require perpetual care. Further, the output will be used by EPA in the short-term to develop general environmental standards applicable to any radioactive waste management alternative