Transient Analysis of Secondary-Side Passive Residual Heat Removal System

One design scheme for secondary-side passive residual heat removal system is presented based on the prototype of AP1000 primary system.The RELAP5/MOD3.2 is used to simulate and analyze the transient process of the PRHR system during blackout accident.In addition,the factors having effects on the capacity of natural circulation and the stability of interface between cold and hot fluid in density lock are analyzed based on the calculation results.The results show that the core residual heat is able to be removed effectively using natural circulation,and the capacity of system can be assured by the PRHR system which is rationally designed,and the height difference between steam generator and PRHR heat exchanger and the local resistance in density lock are the principal factors having effects on the operating capacity of system.