Repository performance assessment and advanced fuel cycle models for input to decision making of options for nuclear waste and resource management

A methodology and computer software is described which can be used to track the inventory of radionuclides as they are affected by various nuclear, physical and chemical processes during reactor, storage, effluent and disposal phases of the nuclear fuel cycle. Such a model is required to provide an assessment of economic, environmental and societal performance indicators which underpin decisions regarding options for the use and management and nuclear materials. An example generic deep repository model is described which can be used to provide an indicator of environmental performance of vitrified high level waste and UO2 and mixed oxide (MOX) spent fuels. The assessment models highlight the significance of the I-129 fission product which necessitates the use of appropriate dose assessment models to be considered for each process step of the nuclear fuel cycle in order that a complete environmental assessment of process options can be determined. (author)