Cause analysis for valve seat breakage of letdown regulating valve

The chemical and volume control system (RCV) is an important auxiliary system for nuclear power plants. In this system, the letdown regulating valve, as an extremely important component in the automatic control system, plays an important role. In a certain nuclear power plant, there were two cases in which the letdown regulating valve was not regulated correctly. In this paper, the test study is carried out for the fracture of the valve seat, the cause is found out, and relevant valve installation improvement program is put forward. (authors)