Single point failure analysis and innovative practice of speed control loop of main feed pump in NPP

In the operation of nuclear power plants, the speed-adjustable electric main feed pump has experienced several sudden speed drop faults, which leaded to power reduction or shutdown. According to the INPO AP913(Equipment Reliability Management Guide) reliability analysis method, the main feed pump speed control circuit is identified as the Single Point Vulnerability. In order to improve the reliability of the speed control loop, the paper studied the equipment failure mode of the main feed pump speed control loop based on the internationally accepted AP-913 as a guide, classifies the equipment, and puts forward targeted preventive maintenance, isolation mitigation, technical mitigation measures to improve equipment reliability. Moreover, further the SPV sub-component recognition and failure mode analysis are carried out. The program is validated by actual verification and can be applied to the transformation of the main feed pumps of other M310 units and HPR1000 units. (author)