Nuclear fuel recycling: National and regional options for the US nuclear energy system

Abstract

A system dynamics model is applied to study the impact of spent fuel recycling on the US nuclear energy system and the implications of a bilateral hypothetical collaboration between the US and Brazil. In particular, the impact of different options for advanced fuel cycle facilities needed for the US nuclear energy market alone and under a Brazil partnership is studied. Different recycling technology options are considered: (1) thermal recycling of transuranics (TRUs) in Light Water Reactors (LWRs) using Combined Non-Fertile and UO₂ Fuel (CONFU); (2) recycling of TRU in fertile-free metallic fuel in fast Actinide Burner Reactors (ABRs); and (3) fast recycling of TRU with UO₂ in self-sustaining Gas-cooled Fast Reactors (GFRs). These recycling options are truly advanced and will require significant development, but they allow the evolution of nuclear energy systems with minimum transuranic elements in the nuclear waste, hence reduce the long term environmental burden of the waste. Case studies for different advanced technology introduction dates are examined under a prescribed rate of growth in demand for nuclear electricity. The timing of introduction of recycling is important for proper technology development. In the model, the rate of deployment is restrained by the industrial capacity to build TRU separation plants, as well as the desire for high utilization factor of the deployed facilities over their life time. It is notable that all recycling options result in only modest reductions in total uranium consumption at the end of the century. Due to its unity fissile conversion ratio, early introduction of the self-sustaining GFR recycling scheme leads to the largest reduction in uranium consumption and enrichment requirements, about 20%. On the other hand, the CONFU recycling scheme keeps the TRU inventory in the entire system well below other schemes, and guarantees equilibrium between the generation and consumption of TRU without investments in fast reactors. The three schemes reduce the TRU sent to the repository for disposal by two orders of magnitude, but the ABR and the GFR schemes require the introduction of the more costly fast reactors. The rate of deployment of fast reactors becomes limited by the availability of TRU from LWRs in the last quarter of the century. Moreover, an assessment of the impact on the US nuclear energy system of a major commitment to supply the nuclear fuel cycle needs of other countries, with Brazil as the example, is made. The partnership with Brazil implies that the US recycling facilities would be used at higher utilization factor, and more TRU will be available to start fast reactors in the US. Economic analysis for the US nuclear energy market indicates that the CONFU technology is more attractive at current uranium price level, and that fast recycling becomes as attractive as thermal recycling at much higher uranium prices.