Tritium Control for Flibe/V-Alloy Blanket System

One of the critical issues of Flibe/V-alloy blanket with REDOX control by Be is a large tritium inventory in V-alloy structures. Among the possible solutions to this issue would be to control REDOX not by Be but by addition of MoF₆ or WF₆ enhancing the reaction from T₂ to TF. The present study investigated feasibility of this procedure by thermodynamic and neutronics calculations. Using the blanket dimensions of Force Free Helical Reactor (FFHR), tritium inventory in V-alloy structure and Flibe were estimated based on the calculated equilibrium partial pressures of T₂ and TF in various cases of REDOX control by MoF₆ or WF₆. Also carried out were neutronics examinations for the impact of Mo or W doping in the blanket. The results showed that the tritium inventory in the blanket area would be less than 100g at the TF level of 0.1 and 1 ppm in Flibe with addition of WF₆ and MoF₆, respectively. WF₆ doping is far more advantageous than MoF₆ doping for low activation purposes.