Research On Pressurized Water Reactor Pressurizer Control System Based On Intelligent Control Theory

With the continued growth of the world’s population as well as peoplegradually increase the requirements of the standard of living, the world’senergy demand is increasing constantly. However, for a long time, theexcessive consumption of fossil fuels gives the world a serious problem ofenvironment pollution. And the nuclear power can be used as a new greenenergy, which does not discharge pollutants into the environment as burningcoal. Currently, the vast majority of the countries are developing and using thenuclear power actively. It is foreseeable that the vitality of the nuclear powerwill inevitably increase as time goes on.PWR (Pressurized Water Reactor) nuclear power station is mainlycomposed of main loop system and secondary loop system. And the main loopsystem consists of the reactor, the main pump, the pressurizer, the steamgenerators and the corresponding pipelines and so on. The pressurizer is animportant equipment in the PWR nuclear power plants, and the role of the pressurizer control system is to keep its water level and the pressure aroundthe set value. In other word, the pressurizer maintains its internal water andsteam in the saturated state balance. The water level can not too high or toolow. The higher water level will make the pressure regulator failure and thelower water level will make the electric heater exposes in the steam space andburned. And the pressure of the system should be maintained within a certainrange. The higher pressure will destroy the system pressure boundary, and thereactor core will occur DNB (Departure from Nucleate Boiling) when thepressure too low.The nuclear reactor pressurizer is a controlled object, which have thecharacteristics of large inertia, complicated and multi-interferences. And itscontrol method has been always paid attention. Currently, the water levelcontrol system and the pressure control system of the pressurizer adoptconventional PID control mostly. We just need to appropriately adjust PIDparameters to achieve the control requirements in the base of acquisition themathematical model of the controlled object. However, the PWR pressurizersystem has complex dynamic characteristics; its precise mathematical modelcan not be obtained accurately. Besides, the parameters of conventional PIDcontrol method can not be changed once been set, so it can hardly adapt tovarious disturbance and the change of the object, leading to the bad controleffect, such as: the large overshoot, the long adjustment time, the long risetime and the poor control precision and so on. In addition, for such a dual-inputs and dual-outputs system, coupling exists between water levelsystem and pressure system, bringing a greater challenge to the tradition PIDcontrol method.This main content of this paper include: firstly finish the dynamiccharacteristics test experimental of the PWR pressurizer in a nuclearlaboratory simulation platform; and then learn the theory of intelligent controland its advantages based on the traditional PID control method; and finallycomplete the simulation based on MATLAB software. The simulation resultsshow that the stead state performance has been greatly improved whencompared with the traditional PID control.