Study on Method of Pneumatic Test for Pressure Vessels in NPP Nuclear Island

According to the requirements of the in-service inspection code and program, periodic hydrostatic test should be carried out for the nuclear island pressure vessels of the French-system nuclear power plant. However, due to the reasons of system design, some vessels can not be subject to hydrostatic test with liquid, but can only be subject to pneumatic test. In this paper, the implementation requirements of pneumatic test in domestic and foreign codes are compared and analyzed, and combined with the process of pneumatic test in the stage of nuclear island installation, the test pressure, test medium and acceptance standard of nuclear island pressure vessel are selected. At the same time, combined with the risk analysis and radiation protection requirements of the vessel hydrostatic test, the protective measures for the pneumatic test are formulated. According to the above test parameters and risk protection measures, the pressure vessel pneumatic test is successfully carried out in the nuclear island of a nuclear power plant, providing important reference for the pressure vessel pneumatic test of the nuclear island in the subsequent in-service phase.