Neutronics performance evaluation of fast-fission fuel breeding blankets for a fusion–fission hybrid reactor

An investigation was conducted to evaluate the range of performance of several kinds of fast-fission natural uranium blankets adopted different fuel forms: oxide form, carbide form, nitride form, and metallic form based on plasma parameters of the FDS-FB (Fusion Driven Sub-critical System for Fuel Breeding). The objective parameters of the performance were in terms of four figures of merit (FOMs), which consist of fissile fuel breeding mass (FFBM), the blanket energy multiplication (M), tritium breeding ratio (TBR) and the waste produced mass (WPM). The results showed that the best characteristic parameters of FFBM and M were found in the blanket loaded with metallic uranium fuel, followed by carbide fuel, nitride fuel and finally the oxide fuel in two cases of with and without considering tritium self-sustaining. Metallic uranium was found to deposit with the smallest waste inventory, and the fast-fission blanket loaded with carbide uranium or nitride uranium showed significantly higher waste produced mass.