Electromagnetic Simulation And Optimization Design Of Magnetic Control Rod Drive Mechanism

With the rapid development of science and technology and economy in the world,the problem of energy shortage has become increasingly prominent.As a clean energy with good environmental protection、safety and economy,nuclear nergy is more and more favored by all countries.Nuclear power is one of the most widely used forms of nuclear energy,and the development of nuclear power is an important guarantee for China’s national security.Pressurized water reactor(PWR)is one of the most commonly used and mature nuclear power reactors.Nowadays,magnetic control rod drive mechanism(CRDM)is widely used in PWR nuclear power plants.The magnetic control rod drive mechanism uses electromagnetic force and the gravity of the moving components to complete the lifting,lowering,holding,and rapid fall of the control rod,so that the reactor can realize the functions of safe starting,stopping the reactor,and adjusting the power.Electromagnetic design is the key technology to ensure the safe and stable operation of magnetic control rod drive mechanism.In the past,engineers and technicians have done a lot of related research on CRDM,but there are still some problems:(1)engineers and technicians have carried out detailed electromagnetic analysis and calculation on CRDM,and deduced the solution process of electromagnetic force,but they have not clearly deduced the determination process of electromagnetic coil current(2)the motion process of magnetic control rod drive mechanism is a complex dynamic process of electromagnetic field-flow field-motion field coupling,which involves multi-disciplinary problems.In the past,a single simulation software was used to simulate the process of a certain state,but the joint simulation was not done from the perspective of multi field coupling,and the results have large errors.(3)The motion of magnetic control rod drive mechanism is the result of multi-field interaction,involving multiple parts.The existing researchers have little research on the armature,which is one of the main collision parts.The armature is prone to collision and wear,which affects the service life of the whole drive mechanism.In view of the above-mentioned problems,this paper conducts electromagnetic simulation and optimization design research on the magnetic control rod drive mechanism.The main research results include:(1)Aiming at the complex motion process of the magnetic control rod drive mechanism,the motion process of the drive mechanism and the force of the armature component are analyzed,the dynamic equation when the armature starts to move in the electromagnetic dynamic response process is determined,and the drive mechanism is studied.It involves the dynamic response process of electric field-magnetic field-flow field-sports field.From the perspective of electric circuit and magnetic circuit,the method for determining the electromagnetic coil current of the driving mechanism is deduced,and the calculation model of the electromagnetic force of the driving mechanism is established.(2)Based on the two-dimensional model of the magnetic control rod drive mechanism,during the lifting phase of the drive mechanism,the pull-in process of holding armature,moving armature and lifting armature was analyzed with the help of ANSYS Maxwell,and the corresponding numerical simulation analysis method was established.The influence of the number of coil turns and current,air gap size,magnetic ring spacing,electromagnetic coil spacing and the electromagnetic force are analyzed.(3)The influence of the verification of the independence of the armature grid on the simulation results of the armature collision of the driving mechanism is studied.During the lifting phase of the driving mechanism,the collision process of holding the armature,moving the armature and lifting the armature is analyzed,and then the lifting armature in the lifting phase is analyzed.The force situation and the position of the maximum stress during the collision,and the lifting armature is determined as the object of optimization design.(4)Regarding the lifting armature as the optimization object,the optimization design process of the driving mechanism lifting armature based on the agency model was established.By analyzing the functional characteristics and structural characteristics of the lifting armature,the design variables and their ranges and optimization goals are determined.Based on the accuracy comparison of multiple surrogate model methods,the standard second-order response surface method was selected to establish a surrogate model to improve the armature optimization problem.With the help of the multi-objective genetic algorithm,the optimal design variable parameters are obtained,and the optimized design of the lifting armature is completed.