Evaluation of Neutronic and Thermophysical Characteristics of Molten Salts Specialized for Long-Lived Fission Products Transmutation in a Fusion Reactor
Plasma and Fusion Research
This study proposes new molten salts, which are specialized for transmuting long-lived fission products (LLFP) using a helical fusion reactor FFHR-d1, as a neutron source. Molten salts are binary systems consisting of BeF 2 and LLFP fluorides, such as BeF 2 -ZrF 2 , BeF 2 -PdF 4 , or BeF 2 -CsF. This study evaluates the effect of molten salts on the transmutation performance, and the amount of heat generated was evaluated by Monte Carlobased neutron transport and burnup calculations. Therefore,
... lations. Therefore, when the transmutation area was fixed at 4% of the blanket system volume, the higher molar ratio of LLFP fluorides leads to higher transmutation performance. Also, the viscosity, specific heat, and thermal conductivity of BeF 2 -CsF were evaluated by molecular dynamics (MD) simulations. The heat transfer characteristics were evaluated by calculating the Prandtl number from MD simulation results. The Prandtl number of 50% CsF, which produced the lowest melting point (475 • C), was evaluated to be 29.23, which was 60% larger compared to the Prandtl number of Flibe (LiF-BeF 2 ) when the BeF 2 molar ratio was 50%. This result suggested that the heat transfer performance was inferior to that of Flibe.