Study On Passive Residual Heat Removal System Design And Simulation

The nuclear power units should take emergency measures to remove the residual heat when it occurred blackout accident, the passive residual heat removal system with natural cycle characteristics of itself, can cool the core without external power, and ensure the safety of the reactor. This paper presents several different forms of passive residual heat removal system (PRHRS) program: seawater cooling solution, cooling water tank solution, air cooling solution and buffer tank solution. These programs have their own advantages and can meet core cooling requirements under different conditions for different types of nuclear power units.The design calculation determined the heat exchanger structure and main dimension of different programs based on the natural circulation characteristics. On this basis, the RELAP5 code is used to simulate the work condition of primary system and the PRHRS under the blackout accident, the dynamic characteristics of the reactor thermal hydraulics results show that the natural circulation is established to removal the residual heat and the PRHRS of different programs are available to ensure the core security. Finally, we analysed some main design parameters' effect on the system and the results showed that: the bigger the design parameters are, the easier the natural circulation establishment was made, the PRHRS can own stronger heat capacity, but too stronger heat capacity would lead the operating parameters change too fast, it may not good for the stability of the system and equipment safety.In this thesis, the design of different PRHRS were able to remove the residual heat under accident conditions, to ensure safety of the core, different PRHRS can meet requirements for different types of nuclear power units under different operating conditions; the work can provide some reference to the passive safety systems using in nuclear power units.