Analysis of operation time of ETY scavenge loop in nuclear power plants

The concentration of inert gas has risen and the content of oxygen has decreased in the containment vessel in recent years. The concentration of gas in the containment exceeds the national standard for personnel to work. The inability of personnel to enter the containment to carry out maintenance has led to the delay of the overhaul of nuclear power units, which has brought a certain economic losses. Nuclear power plants would like to reduce the content of inert gas or increase the content of oxygen in the containment vessel by operating the Containment Atmospheric Monitoring system's scavenging loop, to meeting the national standards for staff entering the containment. The one-dimensional analytical model and the method of safety impact analysis of probability are adopted to analyze the inert gas and oxygen concentration's changes in the containment after the Containment Atmospheric Monitoring system's scavenging loop has been put into operation, as well as the effects on the third shielding of nuclear power plants, and provide reasonable suggestions for the operation time of the Containment Atmospheric Monitoring system's scavenging loop. (authors)