Gas-driven permeation of deuterium through tungsten with different microstructures

Permeation behavior of deuterium (D) through various tungsten (W) materials, including rolled, annealed, recrystallized W and ZrC/La2O3-dispersion strengthened W, has been studied. Experiments were performed using a gas-driven permeation facility in the temperature range of 700-1000 K. The permeability of D was not sensitive to the dislocations/vacancies or ZrC/La2O3 phases in W, and the measured permeation values are comparable to Frauenfelder and Zahkarov's data. The diffusivity of D, however, is microstructure dependent. The higher the density of defects was, the lower the effective diffusivity was measured. These results imply that dislocations/vacancies or small amounts of ZrC/La2O3 phases in W will not influence the hydrogen isotopes steady state permeation flux through the first wall.