Investigating permeation and transport of H isotopes in tungsten by first-principles

• W and W-alloy are considered as the promising plasma facing material.
• Hydrogen isotopes (H, D, T) have large effect on the properties of W.
• Permeation and transport of H isotopes is very important in W.
• Especially, permeation of T in W is a great concern of safety.

We have investigated permeation and transport of hydrogen (H) isotopes in tungsten (W) single crystal employing first-principles calculations in junction with Fick’ law. Permeability was approximately evaluated according to the solubility and diffusion coefficient of H. The solubility for H in bulk W from present calculation is consistent with the experimental results measured by Frauenfelder. The permeation fluxes of H isotopes are examined at the different thickness of W wall. The permeation fluxes of deuterium with the W thickness of 21 μm at the temperature of 770 K and with the W thickness of 50 μm at the temperature of 893 K were 0.68 × 1013 atom/m2s and 0.34 × 1014 atom/m2s, respectively. The dissociation coefficients of H isotopes are also evaluated. We believe that the present first-principles combined with Fick’ law method can be also generalized to investigate permeation and transport of H isotopes in most metals since such H isotopes behaviors in most metals are similar to those of H isotopes in W.