Radioactive gaseous waste processing device

The present invention provides a device for continuously removing a moisture content in radioactive gaseous wastes (off gas) generated from a BWR type power generation plant. Namely, in a dehumidification device by utilizing hollow thread membranes of an off gas processing device, thermometers are disposed for measuring each of the temperature of off gases and the temperature of entrance of the off gas dehumidification device. A heater is disposed for heating the inside of the dehumidification device to a state corresponding to the temperature of off gases. A control device for controlling the heater by comparing the temperate of inflown gases and the temperature of the body of the dehumidification device. The inside of the dehumidifying device is heated to a temperature at or higher than the temperature of inflown off gases. Then, condensation of the moisture content contained in off gases in the dehumidification device can be prevented. In addition, if demister is disposed to an entrance nozzle portion of an off gas entrance chamber of the dehumidification device, mist of inflown off gases can be removed thereby enabling to improve steam permeation property of a hollow thread module. (I.S.)