Hydrogen retention and release behaviour during full life use of ZrVFe alloy for isotopic water processing

Abstract

In this paper, we present the results of an experiment wherein Zr[V 0.5Fe 0.5] 2 alloy has been used for the conversion of light water vapour to hydrogen at a temperature of 400°C and partial pressure of ∼4 kPa through a series of batch processes nearly up to its full life. After ∼1960 cumulated hours of conversion, the oxygen uptake was found to be ∼2.24 moles of oxygen per an equivalent mole of alloy. Systematic investigations of the conversion process revealed a reduction in the hydrogen release capabilities as the oxidation of the alloy increased. The role and consequence of the hydrogen and oxygen atoms resulting from the cracking of water vapour molecules at the alloy surface are discussed from the observed dependences of the hydrogen release on the duration of conversion and the relaxation time between two successive conversions. The significance of the experimental results towards the usage and disposal of the alloy material, for the purpose of tritiated water conversion in a fusion reactor situation, is also discussed.