Distributed process interlock system for LWR

The process interlock system is one of the systems of the primary plant control system for light water reactor. This system controls all the primary plant equipment's such as pumps and valves by implementing the process interlock logics. The system consists of six geographically distributed, physically distinct sub systems. All these sub systems are microprocessor based triple modular redundant systems and they are connected via a triplicated serial bus. This system also communicates with the data acquisition system via a dual redundant serial bus. The paper describes in detail, the system architecture and highlights the fault diagnostics features that are incorporated in the system. (author)