Root Cause Analysis of Ventilation System Motor Shaft Fracture in Nuclear Power Plants

The motor shaft rupture incident of Ling’ao nuclear power plant was analyzed by the international popular technique of root cause analysis.Firstly,all the probable failure modes of the motor rupture cause were analyzed with the efficient analytical techniques of Metallographic,Scanning Electron Microscope,Spectral Element Analysis,Stress Analysis and the Feedback of the Maintenance and Vibration test.And then the non-related failure modes were rejected,and the root cause and the contributor cause of the motor rupture were evidenced.Finally,the efficient maintenance and management advice are given to ensure the similar motor in a safe and reliable condition.