High-Pressure Hydrogen Isotopes Sources Based on Vanadium Hydride

Equilibrium pressures of protium and deuterium desorption over a two-phase area of monohydride-vanadium dihydride were measured. Temperature measurement range was 300-635 K and the pressure range 1-500 MPa. Obtained temperature-dependences of fugacities within the given measurement range are: lgf(MPa) = -2152/T+ 6.6 and lgf(MPa) = -2575/T + 7.4 for protium and deuterium, respectively. The values of enthalpy and entropy for vanadium dihydride phase formation were calculated from obtained relations. Using expressions obtained for fugacities and literature data on hydrogen imperfection the pressures, which can be obtained with vanadium dihydride employed in thermodesorption hydrogen sources, were estimated. Taking into account that due to deterioration in strength properties of the used structural materials, the heating temperature of the load-bearing body is limited to ∼973 K, maximal calculated pressure, which can be obtained with such sources as ∼1820 MPa for protium and ∼2220 MPa for deuterium.