Hydrogen extraction from a helium purge gas comparison of the ZrCo/ZAO getter material

From the known getter materials proposed for the storage, supply, and recovery of hydrogen isotopes the interalloy ZrCo has been selected as reference material. However, because of disproportionation occurring after prolonged thermal cycling, ZrCo loses its ability to reversibly absorb, or desorb tritium. Therefore, several other interalloys such as ZAO have been suggested as potential candidate materials to replace ZrCo. The new materials need to be tested and compared to ZrCo, before their use as replacement to ZrCo. In this report, the same amount (48 g) of both materials (ZrCo and ZAO) are subjected to the same experimental conditions, i.e. to several successive loading-deloading cycles (LDCs) and their performance in terms of absorption/desorption of hydrogen is compared.
This report describes a comparison of the results obtained for both interalloys. It is remarkable to see that although several consecutive LDCs are very similar for ZrCo, this is not the case for ZAO. A constant feature of ZAO is that the first LDC is very different from the subsequent LDCs, since after the first LDC the material does not release the entire amount of hydrogen absorbed during the 1st cycle. ... mehrThis behaviour indicates that for its regeneration, ZAO requires much higher temperatures than the∼430ºC used here, although 430ºC is enough to regenerate ZrCo. Furthermore, the formation of several hydrogenated species involving some other ZAO's constituents (V, Ti, etc.…) could also explain the need for a higher regeneration temperature, some of them are assumed to have different activation energies for the hydrogen release and therefore require higher regeneration temperatures.