Hydrogen Extraction Characteristics of Proton-conducting Ceramics under a Wet Air Atmosphere for a Tritium Stack Monitor

概要

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For the purpose of designing a tritium monitoring system combined with proton-conducting ceramics as a membrane separator, the hydrogen pump characteristics of CaZr0.9In0.1O3−α proton-conducting ceramics were evaluated. In the experiments, argon gas containing 20.7% oxygen and 1.2% water vapor was fed to the anode at a rate of 47–137 ml/min at 600–800°C and an applied voltage until 3.5 V. The resulting hydrogen evolution rate reached maximally 0.67 ml/min and the hydrogen recovery rate was 60%. However, the proton transport number decreased to 0.52 because the electron-hole current increased along with protonic current according to the defect equilibrium reaction occurring under a wet atmosphere containing oxygen. During operation, the hydrogen evolution rate fluctuates over time by at least 0.1 ml/min, which is approximately 20% of the hydrogen evolution rate. Additionally, the hydrogen evolution rate increased with an increase in the partial pressure of water vapor at the anode. It is important to design the tritium monitoring system taking into consideration the fluctuation in hydrogen evolution rate.
社団法人日本原子力学会の論文
2004-10-25