Development of a fixed inert gas monitoring device

[Background] After the Fukushima nuclear accident, China's nuclear power authorities have put forward new requirements for the safety management of nuclear facilities in operation. A variety of radioactive inert gases are produced in nuclear power plant (NPP) accidents. [Purpose] The aims of this study is to develope a special inert gas monitoring device for NPP. [Methods] With the combination of flow gas differential detection component and local processing/display unit, a fixed inert gas monitoring device was developed by integrating the relevant detection device, filter device, gas sensing instrument (flowmeter, pressure gauge), sampling pipeline, valve (stop valve and regulating valve), sampling joint and various components together on this fixed equipment platform. The sensitivity of the detector was predicted by using simulation software MCNP to ensure the satisfaction of requirements. [Results] The fixed inert gas monitoring device developed in this study not only preserves all functionalities, optimizes the measurement index, but also reduces the volume and weight. Compared with the similar equipment, the integrated layout is convenient for maintenance and management with better performance index, smaller volume and lighter weight. [Conclusions] This device canbe employed to monitor the activity concentration of radioactive inert gas in the environment more quickly and accurately, find the leakage of radioactive gas in the nuclear power plant in time, and ensure the safe operation of the nuclear power plant and the radiation safety of the field personnel. (authors)