Basic considerations and prerequisites for the assessment of future fuel cycles with special regard to P and T issues

The radio-toxical evaluation of actinides and long-lived fission products will be presented and discussed with special regard to Partitioning and Transmutation (P and T) issues. Calculations for different fuel types are exhibited and the resulting toxicity potentials are compared to the time-dependent values of charged fresh fuel in order to solely quantify in an idealized way the consequences of human intervention. The long-term toxicity potentials for the direct disposal of PWR fuel elements and the Pu-recycling within MOX elements using U and Th as diluent are presented. The inherent drawbacks lead to the conclusion that with respect to a modified goal of final disposal only a full-scale P and T scheme is able to achieve long-term toxicity potentials on the same level as that of fresh fuel decaying naturally. Thus, the storage in a repository can relay more heavily on engineered barriers. (authors)