Distillation Column for Hydrogen Removal in Liquid Lithium PFC Systems

Tritium trapping in liquid lithium plasma-facing components remains one of the major counterarguments to the use of lithium in fusion devices. This trapping could contribute to tritium inventory concerns and the loss of the low recycling boundary. As such, it is crucial to develop technology for the removal of hydrogen and other impurity species. These systems can prevent lithium saturation, reduce corrosion of materials, and limit the clogging of distribution systems. At the Center for Plasma-Material Interactions (CPMI), a distillation column has been developed to thermally treat the liquid lithium and remove the hydrogenic species.

The Hydrogen Distillation Experiment (HyDE) has shown the ability to remove hydrogen from static Li/LiH systems at rates (3x10¹⁸ H₂ cm^-2 s^-1) applicable to large scale fusion devices, while operating at reasonable temperatures (<750°C). HyDE also demonstrates the ability for lithium capture and initial re-flow back to the main lithium system. Moving towards a complete flowing system is the next step in the development of hydrogen extraction technologies. The distillation column is being adapted to a flowing lithium system with in-situ hydrogen flux to an open-surface PFC. Current status of the lithium loop and distillation addition are presented.