Research on Lift Pole Thread Fatigue of Magnetic Lifting Control Rod Drive Mechanism

Control Rod Drive Mechanism（CRDM） is a servomechanism of reactor control and protection system,and it is the only movable equipment in reactor body.Its reliability affects the reactor safety and operation directly.Especially in accident conditions,CRDM must release the control rod to insert into the core immediately.This paper presents the thread fatigue analysis of the CRDM lift pole through electromagnetic analysis,mechanical analysis and fatigue analysis method,and presents a fatigue analysis method for thread bearing impact load in Magnetic Lifting CRDM.This method can be used in the analysis and design of the similar type of CRDM.