Abstract
The accident at TEPCO's Fukushima Daiichi nuclear power plant was expanded into severe accident (reactor damage and hydrogen explosion). The instrumentation systems for the severe accident of the nuclear plant are being developed1). In order to prevent the hydrogen explosion, the hydrogen concentration sensor is being developed. Although almost sensor could not be adopted by the severe accident's environment, the solid oxide electrolyte type hydrogen sensor (proton conductor) was selected for its durability to high temperature and high pressure. In the fabrication process of the sensor, the joining techniques for metal part and solid electrolyte (ceramic) is very important. After heat cycle test and pressure cycle test for joints, the test results confirmed the soundness of the ceramic parts and joints. By the hydrogen measurement in inert gas and air, it shows the theoretically predicted behavior (Nernst's Equation) in inert gas, and linear relationship between electromotive force (emf) and hydrogen concentration (logarithm) in air. It was able to confirm the feasibility of this method. Furthermore, the operating characteristics of the sensor under irradiation shows data on irradiation effect. In this paper, the performance test results of the hydrogen sensor under various conditions are presented.
