The physics of TRU transmutation - A systematic approach to the intercomparison of systems

In this collaborative effort, a methodology is developed to enable systematic analysis and comparison of diverse nuclear fuel cycle strategies. First, transmutation potential is assessed by considering the neutron balance for destruction of each actinide isotope; a range of thermal and fast reactor systems are considered. In general, a harder neutron energy spectrum results in a more favorable neutron balance. The method is extended to compute equilibrium actinide compositions for a generalized fuel cycle model (open or closed). In this paper, the technique is employed to compare the transmutation performance of 1) PWRs with varying moderator-to-fuel ratio, 2) PWR closed cycle strategies with varying treatment of the minor actinide elements, and 3) fast reactors with either plutonium or transuranic recycle. The method is demonstrated to quickly evaluate the main characteristics of the associated fuel cycles (e.g., isotopic mass flows, neutron balance for critical enrichment) and give some indication of other performance parameters (e.g., reactivity effects).