ABSORPTION OF ATOMIC HYDROGEN BY VANADIUM

In order to understand the capability of vanadium panels and membranes for fuel particle pumping at relatively low temperatures, absorption of neutral hydrogen atoms by vanadium sheet was examined at/below 350 °C under wide variety of experimental conditions. A niobium sheet kept at high temperature (420 °C) was used as a reference specimen. Sufficiently high absorption rates were obtained even at around room temperature in the range of incident fluxes from 101 7 to 1021 m -2 s -1 . No noticeable reduction in absorption rates was observed up to the H retention level of 0.1 at%. The influence of CO and water vapor was negligibly small up to an exposure of 1023 m -2 . Significant reduction in the absorption rate was observed only when an oxide film was formed on the surface by exposure to O 2 to 10 20 m -2 and to H 2 O over 1023 m -2 at room temperature.