核电厂主蒸汽隔离阀控制系统故障分析及可靠性提升

主蒸汽隔离阀是核电厂核岛与常规岛间主蒸汽管线上最重要的隔离设备，主要介绍了秦山第二核电厂1/2号机组主蒸汽隔离阀控制系统功能及控制原理、故障模式分析。结合历史故障统计得出系统的薄弱点—限位开关，并对限位开关故障失效机理和根本原因分析进行了重点阐述，最后针对系统的可靠性提升从人、机、料、法、环5方面提出了改进措施，对国内其他在役核电厂主蒸汽隔离控制系统维护和改进有一定的借鉴和参考意义。 

Failure Analysis and Reliability Improvement of Control System of Main Steam Isolation Valve in Nuclear Power Plants

The main steam isolation valve is the most important isolation equipment of the steam pipeline between the nuclear island and the conventional island in nuclear power plants. This paper mainly introduced the function and control theory, and the failure mode analysis. Combined with the historical fault statistics, the weak point of the system-limit switch is obtained, and the failure mechanism and root cause analysis of limit switch failure are emphatically expounded. At last, the paper puts forward the improvement measures from five aspects: human, machine, material, method and environment, which has certain reference significance for the maintenance and improvement of the main steam isolation control system of other nuclear power plants in service in China.