Hydrogen and Deuterium Permeation on Niobium Coated by Ultrathin Pd25%Ag for Tritium Recovery in EU Demo

The hydrogen and deuterium permeation in pure niobium and niobium Pd25%Ag coated are measured using a permeation gas phase technique. The coating with different thicknesses, are deposited on Nb by a Dual Ion Beam Sputtering Technique. Measurements are performed in the temperature range of 573–723 K with hydrogen or deuterium driving pressures in the range 1.0⋅102−1.2⋅104 Pa (1 to 120 mbar). This work highlights how PdAg-coated Nb membranes can be fruitfully rated in the design of tritium recovery plants where niobium pipes for lead lithium are under consideration. Ultra-thin PdAg coatings mitigate the effects of the oxide in reducing of hydrogen permeation through the niobium walls.