Control device for the burnable gas concentration

Purpose: To surely decrease the radioactive materials within a container upon loss of coolant accidents in BWR type reactors. Constitution: In the control device for the burnable gas concentration according to this invention, airs in the dry well of a container are sucked by a blower and a radioactive material capturing water tank for forcibly capturing radioactive materials in a gas phase is disposed to the upstream of the blower. Further, a feed pump for supplying the liquid to the suppression chamber is disposed. As the loss of coolant accidents proceed and the differential pressure between the dry well and the suppression chamber is decreased, the control system for the burnable gas concentration is actuated to start up the blower and result in a pressure, in which the inner air is released as small bubbles into the liquid phase to forcively capture the water soluble materials and suspended radioactive grains. The remaining internal air is heated, recombined, cooled and then returned to the suppression chamber. The amount of the condensates in the system can be reduced to improve the system reliability. (Kamimura, M.)