Evaluation of Neutronic and Thermophysical Characteristics of Molten Salts Specialized for Long-Lived Fission Products Transmutation in a Fusion Reactor

2020 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,
more » ... 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.
doi:10.1585/pfr.15.2405077 fatcat:gabiw2faxbdnfapm3fpa42rmgu