Absorption/desorption of hydrogen isotopes and isotopic waters by Zr‐alloy getters

Abstract

Zr‐alloy getters have been applied to tritium handling and vacuum conditioning for fusion devices. Some of their properties, however, should be improved to apply them in future devices. From this viewpoint, we have studied the effects of alloying on the getter properties of Zr alloys. We found that the activation energy of absorption and desorption of hydrogen varied considerably with alloying. The activation energy for hydrogen absorption was 0.74 for Zr61Al39, 0.01 for Zr57V36Fe7, 0.63 for Zr67Ni33, and 2.8 kcal/mol for Zr85Ni15, whereas that for Zr was 2.6 kcal/mol. The heat of hydrogen absorption was 27.8 kcal/mol for Zr: it changed with alloying as 32.0–33.4 (Zr61Al39), 27.8–28.4 (Zr57V36Fe7), 29.0 (Zr67Ni33), and 28.0 (Zr85Ni15). In addition, the ratio of the pumping speed of water vapor to that of hydrogen at room temperature varied with alloying element: for example, 1/40 for Zr57V36Fe7 and 1/4 for Zr67Ni33. The alloying effects mentioned above are considered due to modification of the electronic ...