Failure Analysis on Corrosion of Motor Shafts of Motor-driven Feedwater Pumps

Local corrosion were found on motor shafts of motor-driven feedwater pumps for a nuclear power plant when the pumps were overhauled,and the corrosion reasons were analyzed by means of scene macro analysis,chemical compositions analysis,corrosion products energy spectrum analysis and oil sample analysis.The results show that the corrosion of motor shafts was mainly caused by free water in the lubricating oil,and the foreign body in the atmosphere entering into the bearing bush accelerated the corrosion.Finally suggestions were proposed to avoid the similar corrosion failure.