Study on Control Requirements of Radioactive Pollution in Secondary Cycle of PWR Nuclear Power Plants

PWR nuclear power plant steam generator tube leak will result in radioactive contamination, affecting the release of radioactive effluent to the environment. It is necessary to set the leak rate monitoring system and steam generator blowdown system for controlling the secondary cycle system water quality and the radioactive environment release within an acceptable range. By analyzing the migration path of the radioactive secondary cycle, the calculation models of secondary cycle source term and radioactive effluent are obtained. According to the calculation models and assumptions of the secondary cycle radioactive control requirements, the steam generator tube leak rate at design basis is determined, and the design requirements on leak detection system and blowdown system of the steam generator are developed.