Advanced Control and Operator Interface Systems For CANDU 9 Fuel Handling System

Abstract

One of the goals of CANDU 9 plant design is to provide an advanced, state of the art control system and an operator friendly human machine interface to assure error free operation of the Fuel Handling (FIH) system. This system is an evolution from CANDU 6 retaining its proven strengths. Extensive operational experience feedback from CANDU stations was utilized in the design of these systems. An important decision made for the CANDU 9 is that the control functions and operator interface functions are separated into two systems, while providing a tight coupling between them. Another important feature is that FIH control and display systems are part of the overall plant wide control and display systems network while providing full functional and operational independence from the rest of the plant control and display systems. The CANDU 9 FIH control system uses a modern Distributed Control System (DCS) to perform all mechanism controls, process control, sequential control and operational interlocks. An independent hardwired system is provided for safety related interlocks. The system is partitioned and distributed on the basis of natural arrangement and relationships between various FIH equipment. Redundancy is provided where necessary for operational reasons. In addit ion, extensive system monitoring and diagnostic facilities are provided to minimize system down time. A seismic trip system is also incorporated to avoid inadvertent operation of the FIH equipment in the event of any seismic activity. The F/H Display System (FDS) provides the human-machine interface functions primarily through a sit-down FIH operator's console. All normal. abnormal and emergency FIH operations are carried out from this console through 4 CRTs, which provide control and information display functions. The display system provided at this console is designed based on strict human factors guidelines to provide a user friendly and task oriented operational environment. The FM operator has quick access to all the F/H information through a context sensitive display navigation system. The displays are predominantly graphical and require minimal data entry by the operators. Two additional alarm CRTs and a sophisticated annunciation interrogation facility are provided for fault indication and quick diagnosis of FIH problems. A hardwired backup control panel with limited control and monitoring functionality is provided to put the F/H system in to a safe state in case of unavailability of either the F/H DCS or the FDS. Specific features used in the design of CANDU 9 FIH control and operator interface systems are (1) to provide standardization with rest of the plant and (2) to utilize open systems standards and commercially available hardware and software components to build the system. These systems are also designed for easy application to evolving new CANDU plant designs as well as for retrofit applications to the existing CANDU stations.