Simulation Of 600MW Sodium-cooled Fast Reactor Steam Generator

The Sodium-cooled Fast Reactor(SFR)generally includes three heat transfer circuits.The Second Circuit is a unique system of the SFR system.And the steam generator(SG)is an important device that connects the nuclear island with the conventional island.The SFR generally adopts One-through Steam Generator(OTSG)to produce steam with high quality to improve the Rankine cycle efficiency.The OTSG has high maneuverability.However,due to its rapid response to disturbances,the requirements of the control system are relatively high.And a plurality of parallel steam generator modules will be arranged in the secondary circuit system when modular steam generator design is adopted in SFR system.Due to the complicated flow and heat transfer conditions in the OTSG,the calculation is time consuming,and it is difficult to achieve real-time simulation while ensuring accuracy,when simulation of several steam generators is carried on in the same time.Based on the basic conservation equations,a set of models,including heat exchanger heat transfer model,sodium heat transfer model,forced flow boiling heat transfer model,sodium physical property calculation model,water & steam physical property calculation model,friction resistance calculation model,local resistance calculation model,material physical property model,suitable for the transient thermal hydraulic real-time calculation of 600 MW SFR OTSG is established,according to the structural parameters and operating characteristics of OTSG.The heat transfer equation is discretized by the second upwind scheme.And the fourth Runge-Kutta method is used to solve the momentum equations.The models solve the problem that it is difficult to achieve real-time simulation when several steam generators are simulated at the same time.Based on the FORTRAN language,the real-time simulation calculation program is develped.The program meets the requirements of real-time simulation while ensuring accuracy and interfaces with other systems are set in the program.By comparing the steady-state results calculated by the program with the operating parameters of the BN-600 reactor,the correctness of the program is verified.In the simulation of the dynamic characteristics of OTSG,disturbances on inlet parameters,including feed water flow,sodium flow,feed water enthalpy and sodium inlet enthalpy,are respectively disturbed to the system at different degrees,and the dynamic characteristics of OTSG are obtained under various disturbances.The malfunctions,including evaporator tube plug,super-heater tube plug and single steam generator module being isolated from the system,are introduced to the system.The response characteristics and working performance of the whole loop are analyzed.And parallel characteristics of the system are obtained.Results shows that the program meets the requirements of real-time simulation in all above dynamic conditions while ensuring accuracy and the transient response obtained by simulation meets the physical laws.After the program is transplanted to the real-time simulation platform SimExec and combined with other systems,more conditions of 600 MW SFR will be able to be simulated.