Technical background on design of DS recombiner for fusion facility

Abstract Detritiation system of a nuclear fusion facility should maintain its detritiation performance even in an event of accident of the facility such as fire. The major technical background on design of recombiner for tritium oxidation are detailed kinetics data including the impact of possible gaseous impurities on kinetics, characteristics on pressure drop, impact of heat of reaction and effect of flow rate on kinetics. The volume of catalyst is evaluated by the overall reaction rate constant, required conversion efficiency and gas flow rate for processing. Our demonstration showed that the overall reaction rate constant has the effect of hydrogen concentration. Among possible impurity gases, water vapor, ammonia and halogenated acids affect tritium oxidation. Experimental demonstration revealed that the scale of recombiner have little effect on the overall reaction rate constant. The height of the catalyst layer is determined first from the allowable pressure drop considering the upstream line of the recombiner not to be pressurized. Then, the inner diameter of the recombiner is determined from the volume of catalyst. The concept of adiabatic recombiner with a vacuum jacket can be applied to avoid tritium permeation. The rate of tritiated methane produced by side reactions on the catalyst between methane and tritium was negligibly small.