EXTRA: A real time knowledge-based monitoring system for a nuclear power plant

EXTRA is an expert system for industrial process control. The main objectives are diagnosis and operation aids. From a methodological point of view, EXTRA is based on a deep knowledge of the plant operation and topology and on qualitative physics principles. This system represents a considerable step forward in the field of expert-systems because of the size of the knowledge-base and the real-time requirements. A specific application of EXTRA is developed for the BUGEY unit 2 (a 900 MWe pressurized water nuclear unit) concerning the electrical power supplies. This system called ''electrical power supplies supervision'' gives diagnosis in real time of the electric incidental situation origin. A connection to a data base make the expert system able to supply operators with information concerning the consequences of the electrical power system failures on the safety systems, the equipment measurement sensors and certain automatic devices (availability, unavailability, validity, etc.). A simulation part of the system, out of real time, can help the operators or the maintenance team to prepare the withdrawal from service of electric equipment by giving information on the consequences of it, in particular, information concerning the technical specifications. The system will be independently used and managed by the operating crews and maintenance team, but a priority is given to the diagnosis real time supervision. This expert-system will be installed for the beginning of 1989. (author). 5 refs, 2 pictures