Application of Membrane Dehumidifier for Gaseous Tritium Recovery in LHD

In order to perform deuterium plasma experiments by using the Large Helical Device (LHD), the NIFS is planning to install a system for tritium recovery from exhaust gas. NIFS is planning to apply the latest technologies for tritium recovery. Oxidized tritium (tritiated water vapor) contained in the purge gas is usually removed using an absorbent column. However, if a dew point of less than -60 °C could be obtained using a polymer membrane dehumidifier, the equipment could be reduced in size and a more stable dehumidifying performance could be expected. The applicability of a commercially available membrane dehumidifier has been evaluated experimentally. Based on the performance test results, an actual dehumidifier system that combines a membrane dehumidifier and an absorbent column is proposed and verified to be applicable to the LHD.