Study of isotope effects in the hydrogen transport of an 8% CrWVTa martensitic steel

A time-dependent gas-phase isovolumetric desorption technique has been used to assess the isotope effects in the diffusive transport parameters of hyd rogen in an 8% CrWVTa reduced activation martensitic steel in the temperatu re range of 423-892 K and driving pressures from 9 x 10(4)-1 x 10(5) Pa. Ti le experiments have been run with both protium and dcuterium obtaining thei r respective transport parameters, diffusivity (D), Sieverts' constant (K-S ), permeability (Phi), trap site density (eta (t)) and the trapping activat ion energy (E,). Isotope effects on steel are analysed and compared with rr -iron. A new way to derive more accurate tritium transport parameters Is pr oposed.