Deuterium permeation and diffusion in high-purity beryllium

The permeation rate of deuterium through high-purity beryllium membranes was measured using the gas-driven permeation technique. The time-dependent and the steady-state deuterium flux data were analyzed and the effective diffusivities of the samples were determined. Using multilayer permeation theory the effects of surface oxide were eliminated and the diffusion coefficients of the bulk beryllium determined. The diffusion parameters obtained for the extra-grade beryllium samples (99.8%) are D0 = 6.7 × 10−9m2/s and ED = 28.4 kJ/mol. For the high-grade beryllium samples (99%) the parameters are D0 = 8.0 × 10−9m2/s and ED = 35.1 kJ/mol.