Full Digital I&C System in Tianwan Nuclear Power Station Summary of Operational Experience and Analysis of Typical Events

The paper introduces the first full digital Instrumentation & Control System (referred to as "I&C System" hereinafter) in Tianwan Nuclear Power Station in China, in which the computer and Ethernet network were adopted as the technique platform. After introduction of the characteristics and composing of the I&C system, some problems appeared during commissioning and normal operation are described, mainly focuses on I&C system design optimization, major defects elimination and solution, reasons analysis and corrective remedies for typical events. Since the two units were in commercial operation in 2007, "nuclear safety culture" of the station has been promoted persistently, management and administration regulations are strict and precise, responsibilities are clearly assigned, and documentation system is completely developed, work is being continuously improved. The full digital I&C system is maintained by qualified I&C staffs strictly in accordance with the procedures; The full digital I&C system has exhibited its excellent qualities and remarkable characteristics as follows: stable operation, reliable function, friendly man-machine interface, intuitionistic operation and monitoring, easy configuration, and convenient trouble-shooting. Tianwan Nuclear Power Station I&C system has never caused any event that led to change of the unit operation status, thus has contributed great deal to the safe, stable and economic operation of the two units.