An inventory analysis of thermal-spectrum thorium-fueled molten salt reactor concepts

Inventory analyses of thermal-spectrum, thorium-fueled molten salt reactors (MSRs) have been performed to support US Department of Energy fuel cycle screening and evaluation activities within the. A single-fluid, single-zone 2250 MW_th (1000 MW_e) MSR concept with a fuel-bearing molten fluoride salt moderated by graphite was used as the basis for this work. Depletion calculations were performed using SCALE 6.1.1 with ENDF/B-VII.0 nuclear data. Equilibrium conditions were evaluated for several design parameter sets using a methodology developed at Oak Ridge National Laboratory (ORNL) that enables MSR analysis by performing multiple SCALE/TRITON depletion calculations with material flow modeling calculations between time steps. Adequate modeling approximations were identified by comparing results obtained from calculations that used different modeling choices and levels of fidelity. Parametric analyses examined the performance sensitivity of a thorium MSR to different separations approaches and elemental removal efficiencies. Finally, an inventory analysis for a thorium-fueled MSR with full recycling demonstrated how these insights can be applied and showed that such a system appears feasible from a mass flow and reactivity basis.