ANALYSIS OF SOURCE TERM IN SECONDARY LOOP OF HPR1000

抄録

A very minor leak from the primary to the secondary side of the steam generator heat transfer tube may allow a very small amount of primary coolant to enter the secondary loop system during reactor operation, contaminating the secondary loop system. While radionuclides entering the gas phase are ultimately discharged directly into the turbine plant through the turbine leakage or into the nuclear auxiliary plant ventilation system through the condenser evacuation and then discharged from the chimney after monitoring, radionuclides entering the liquid phase in the second-loop system are purified through the steam generator drainage system and the condensate purification system. As a result, for the radiation protection design of nuclear auxiliary systems and turbine plants, the second-loop source term analysis is crucial. The Hua-Long Pressurized Reactor (HPR1000), a third-generation nuclear power plant, was built using experience gained from Chinese commercial nuclear power plant designs, construction, operation, and maintenance. Based on the generation, transfer, and removal of radioactive substances in the HPR1000 unit's second-loop system, the calculation model for the radioactive source term in the second-loop system is established in this paper. The results of γ source intensity analysis in the cooling water of the secondary loop under different operating conditions are given. The findings can be used to analyze dose change, optimize staff occupational exposure dosage exposure during operation, and evaluate radiation protection for the secondary loop discharge system under various operating situations.