Experimental study on full-scale ZrCo and depleted uranium beds applied for fast recovery and delivery of hydrogen isotopes

• Thin double-layered annulus beds with ZrCo and depleted uranium were fabricated.
• Depleted uranium bed delivered 16.41 mol H2 at rate of 20 Pa m3/s within 30 min.
• The delivery property of depleted uranium bed was very stable during the 10 cycles.

Metal hydride bed is an important component for the deuterium–tritium fusion energy under development in International Thermonuclear Experimental Reactor (ITER), in which the hydrogen recovery and delivery properties are influenced by the bed configuration, operation conditions and the hydrogen storage materials contained in the bed. In this work, a thin double-layered annulus bed configuration was adopted and full-scale beds loaded with ZrCo and depleted uranium (DU) for fast recovery and delivery of hydrogen isotopes were fabricated. The properties of hydrogen recovery/delivery together with the inner structure variation in the fabricated beds were systematically studied. The effects of operation conditions on the performances of the bed were also investigated. It was found that both of the fabricated ZrCo and DU beds were able to achieve the hydrogen storage target of 17.5 mol with fast recovery rate. In addition, experimental results showed that operation of employing extra buffer vessel and scroll pump could not only promote the hydrogen delivery process but also reduce the possibility about disproportionation of ZrCo. Compared with ZrCo bed, DU bed exhibited superior hydrogen delivery performances in terms of fast delivery rate and high hydrogen delivery amount, which could deliver over 16.4 mol H2 (93.7% of recovery amount) within 30 min at the average delivery rate of 20 Pa m3/s. Good reversibility as high as 10 cycles without obvious degradation tendency in both of hydrogen delivery amount and delivery rate for DU bed was also achieved in our study. It was suggested that the fabricated thin double-layered annulus DU bed was a good candidate to rapidly deliver and recover massive hydrogen isotopes for fusion energy application.