Device for Measuring Hydrogen Concentration in Containment During Severe Accident

The hydrogen explosion in Fukushima nuclear accident seriously challenged the safety of nuclear power plants in the world. Therefore, strengthening hydrogen concentration measurement in containment has become very important. To raise the nuclear safety level of in-service and under construction nuclear power plants in China, based on a document which was issued by the National Nuclear Safety Administration of China (NNSA, 2012), the function requirements, components, storage, and arrangement outlines of the hydrogen monitoring system after a severe accident was thoroughly analyzed in this article. Besides, two kinds of techniques for hydrogen concentration measurement in containment, respectively for direct measuring method and gas sampling measuring method, were also discussed and compared. Notably, based on the direct measuring method, the 718th Research Institute successfully developed the CH-15 type hydrogen concentration measuring device that suitable for used in severe accident. The hydrogen sensor, with independently intellectual property rights, is based on catalytic principles and installed inside the containment. It has many unique characteristics, such as wide measurement range, high measurement accuracy, and is capable of continuous measurement with multiple points. This device has simple structure and small size, with low energy consumption, so it is very suitable for being installed in the in-service and under construction nuclear power plants in China and abroad.