Monitor system for radioactive exhaust gases

Purpose: To enable safety and efficient detection for radioactive exhaust gases by combining a tritium recovery device and a carbon 14 recovery device or a krypton 85 detector in parallel with each other thereby enabling them to be operated independently. Method: A leading passage is provided for leading radioactive exhaust gases from an exhaust cylinder in a nuclear reactor and a recovery device for water containing tritium and a recovery device for CO2 containing carbon 14 are provided in passages branched from the leading passage in parallel with each other. A returning pipeway for joining the exhaust sides of the recovery device and leading to the reactor exhaust cylinder is provided, in which means for detecting the recovered products from each of the recovery devices for H2O and CO2 is provided. The recovery devices are made usable switchingly between each other. A concentration device for krypton 85 and a radiation detector for detecting krypton 85 are provided in parallel with the recovery devices. (Kawakami, Y.)