Performance of the electrochemical hydrogen pump of a proton-conducting oxide for the tritium monitor

To improve the sensitivity of the tritium monitor, we have proposed a new type of tritium monitor and constructed a prototype system equipped with a closed loop and a proton-conducting oxide as an electrochemical hydrogen pump. To assess the performance of the hydrogen pump using CaZr0.9In0.1O3−α, hydrogen extraction by water vapor electrolysis is demonstrated at a constant current in the temperature range from 873 to 1073 K. The hydrogen extraction rate reached 1.8 cm3/min at 0.5 A and 973 K. The present cell exhibited mixed proton and electron hole conduction and the transport number of protons decreased at relatively high temperatures. This suggested that high temperatures are not required for a hydrogen pump operating under water vapor electrolysis conditions. Furthermore, as an initial feasibility study, a concentration test was performed on hydrogen gas using the closed loop system and hydrogen pump apparatus. It was found that the concentration rate of hydrogen in the closed loop reached five times that of water vapor in the anode compartment over a period of 50 min.