Analysis of fuel alternatives to achieve breeding capability in the FUJI-U3-(0) reactor

In this study, the core physics of the FUJI-U3-(0) small modular molten salt reactor was simulated using the SERPENT code. The cylindrical thermal reactor core was modeled with three concentric regions, each containing distinct fuel channel radii embedded within hexagonal graphite moderator rods. Five molten salt fuel compositions were analyzed, varying the fissile and fertile materials and their respective proportions. After criticality was achieved, key reactor performance metrics, including conversion ratio and waste production, were evaluated. The results led to discussion of the feasibility of a thermal molten salt breeder reactor with different fuel types. Furthermore, APTh1000 and ANGRA-I nuclear waste was incorporated into selected fuel compositions. For APTh1000 waste, an economic assessment of recycled fuel was performed, which revealed that it is more cost-effective and environmentally advantageous compared to fresh fuel. • A thermal breeder molten salt reactor is evaluated, and fast spectrum is discussed. • Multiple molten salt fuel compositions are analyzed and compared. • Neutron spectrum characteristics are assessed for each salt configuration. • Spent nuclear waste is considered as fuel material. • Cost comparison is made between fresh fuel and nuclear waste reuse.