The sensitivity of fuel cycle performance to separation efficiency

Reprocessing separation efficiency is a major design variable in the implementation of advanced fuel cycles as it affects waste disposal requirements, fuel fabrication, system economics, and other fuel cycle system characteristics. Using a newly developed, physics-based integrated fuel cycle systems analysis model, this study investigated the impact of varying reprocessing separation efficiencies on fuel cycle cost (FCC), proliferation resistance and repository impact. Repository impact was captured by the disposal facility capacity governed by thermal output, the projected dose rate, mass inventory, and waste toxicity index. The coupled systems analysis model included fast reactor simulation tool to analyze the depletion in the fast reactor and the requirements for the fresh fuel in transient and equilibrium states. In this calculation, the feedback between separation efficiencies and fresh and discharged fuel compositions was dynamically accounted for. The new systems model was benchmarked against published results and used to investigate a single-tier nuclear fuel cycle scenario in which light water reactors (LWRs) and 0.5 transuranic (TRU) conversion ratio (CR) sodium-cooled fast reactors are deployed in an equilibrium that results in zero net TRU production. The results indicated that fuel cycle system performance is significantly affected by the changes in partitioning strategies and elemental separation efficiency in reprocessing plants. Moreover, the effect of varying separation efficiencies on reactor performance, fuel cycle mass balances and economic performance are discussed.