Research On Fault Diagnosis For Reactor Coolant Pump Based On Nonlinear Frequency Analysis

The reactor coolant pump is the only high speed operation in the reactor coolant system,and very powerful precision equipment. Being the main power source of reactor coolantcirculation, the reactor coolant pump belongs to the key equipment in PWR power station,which is the heart of reactor. Due to nuclear reactor is potentially dangerous, the reactorcoolant pump rotor once has an accident, will cause very serious economic and social impact.Therefore, the condition monitoring and fault diagnosis of reactor coolant pump are veryimportant to ensure their safety and reliability.The reactor coolant pump rotor system is the core component of rotating machinery.There is nonlinear vibration on the rotor system, and nonlinear problem is more obviousespecially in the event of failure cracks. Therefore, in order to better study the dynamicalbehavior of the rotor system, fault dagnosis method of nonlinear frequency analysis is usedfor studying the intrinsic link between nonlinear output frequency response function and therunning state of the reactor coolant pump rotor, and positioning of the main coolant pumprotor crack fault location.The fault dagnosis method of nonlinear frequency analysis is introduced to detect cracksin reactor coolant pump rotor in this paper. The crack fault models of reactor coolant pumpare built by MATLAB program and Simulink toolbox respectively. The frequency responseof pump rotor with a single frequency and multi-frequency external excitation is solved bynonlinear frequency output response functions; results of system frequency domain faulteigenvalues locate the single and multiple cracks failure position. Throughout simulationanalysis to the reactor coolant pump faults, the validity of fault diagnosis method based onnonlinear frequency analysis has been confirmed, so that the method can be used for thedetection of cracks fault diagnosis in reactor coolant pump.