Hydrogen injection into liquid PbLi for fusion applications: Fabrication and commissioning

The self-sufficiency function of a fusion reactor needs experimental validation of the tritium extraction systems at laboratory scale. This implies the employment of dedicated optimized systems for gas solubilization, in order to reproduce the tritium breeding that occurs in the breeding blanket. A novel approach based on forced permeation through a permeable membrane for hydrogen injection into lead-lithium eutectic alloy (PbLi) is proposed. Two complete functional prototypes have been manufactured using niobium and vanadium as membranes. The leak-tightness of both assemblies has been analyzed and tested, taking into account the huge nominal operation temperature (550 °C), requiring the use of special washers, bolts, and gaskets. Hereafter, the commissioning of the prototypes under deuterium flux has been made in a range of temperatures between 350 °C and 450 °C and gas pressures from 1 mbar to 500 mbar. The gas permeation is in the order of 1E-7 mol/m 2 s for the vanadium membrane while for the niobium is in the order of 1E-11 mol/m 2 s. • Vanadium and niobium are potential materials for hydrogen permeation. • They have been used for deuterium solubilization into liquid metals for fusion applications. • The deuterium permeation through vanadium is in the order of 1E-7 mol/m2s while the niobium is in the order of 1E-11 mol/m2s. • A new system to improve experiments of hydrogen interaction with liquid metals has been validated.