The Study On Optimization Of The Secondary Loop Thermal System Of Nuclear Power

Compared with the conventional power system of the ship,the nuclear power system has the significant advantages of high energy density of nuclear fuel,no need for oxygen supply,large propulsion power,stability and controllability,so that nuclear-power ships can get good endurance and reliability.Therefore the nuclear power system has been closely watched and gets rapid development.Converting thermal energy to mechanical energy and electricity energy,the secondary circuit system is the most important component of the nuclear power system in ship,not only providing forward power but also fulfilling the requirement for electricity.To minimize the weight and volume of the device and maximize the efficiency of the whole system,it is necessary and prevalent to study how to design the nuclear system effectively.In this paper,the secondary loop thermal system of the nuclear-power ship in the research project has been optimized.Based on the structural design of the steam generator,the mathematical model was established.And the mathematical model of other equipment was established by using the the lumped parameter method.According to the mathematical models,the simulation models of each device are established to build the complete simulation and calculation platform of the secondary loop thermal system of the nuclear-power ship in the MATLAB.By adopting the inertia weight adaptive adjustment strategy,introducing the concept of cross selection in genetic algorithm and the concept of constraint violation degree,the particle swarm optimization(PSO)has been improved appropriately to enhance the solving ability and make up for the defects that can not solve the constraint problems.Based on the system simulation platform and using the improved PSO,the weight and volume of steam generator and the efficiency of whole system have been optimized.The most suitable parameters combination has been found when the optimization objective is obtained.After optimization,the structural dimensions of the steam generator and the economics of the secondary loop system have been significantly improved.The weight of the steam generator can be reduced by up to 20.51%,and the maximum volume can be reduced by 27.05%,and after two-objective optimization the weight was reduced by 16.88%and the volume was reduced by 24.68%.The host efficiency can be increased by up to 4.512%,and the cycle efficiency can be increased by up to 1.469%,and after two-objective optimization the host efficiency was increased by 4.432%and the cycle efficiency was increased by 0.887%.The best combination of the design parameters determined after optimization was verified,and the results showed that they are within reasonable limits and the constrains are met.Providing theoretical support for the best design of the nuclear power secondary loop thermal system,the results obtained in this paper have some reference value.