Airtight automatic drainage device of radiation monitoring channel

The invention belongs to the technical field of nuclear power plant radioactive gas monitoring, and in particular relates to an airtight automatic drainage device and method of a radiation monitoring channel. The device provided by the invention comprises an oblique tee, a valve, a pipeline and an automatic steam trap which form an automatic drainage line, and an oblique tee, a valve, a pipeline and a bucket which form a manual drainage line. According to the invention, a monitoring channel instrument is prevented from being damaged or failing due to water coming into a monitoring channel measuring chamber; the running safety and availability of the monitoring channel are improved; outside gas is prevented from flowing back into the radiation monitoring channel, which ensures the accuracy of monitoring data and the system safety; the manual drainage line is set; when the automatic drain line is failed or maintained, condensate water is drained through the manual drainage line; and the redundancy and reliabili