Background: Control rod drive mechanism（CRDM） is one of the important safety-related equipment for nuclear power plants.Purpose: The operating parameters of stepping movement

including lifting loads

step distance and step velocity

are all critical design targets.Methods: FEA and numerical simulation are used to analyze stepping movement separately.Results: The motion equations of the movable magnet in stepping movement are established by load analysis.Gravitation

magnetic force

fluid resistance and spring force are all in consideration in the load analysis.The operating parameters of stepping movement are given.Conclusions: The results

including time history curves of force

speed and etc

can positively used in the design of CRDM.