MPGV: an expert system for steam generator maintenance

The tube bundles in PWR steam generator are, by far, the major source of problems whether they are due to primary and secondary side corrosion mechanisms or to tube vibration-induced wear at tube support locations. Because of differences in SG operating conditions, materials, and fabrication processes, the damage may differ from steam generator to steam generator. MPGV, an expert system for steam generator maintenance uses all steam generator data bases containing data on materials, fabrication processes, inservice inspection, and water chemistry. It has access to operational data for individual steam generators and contains models of possible degradation mechanisms. The objectives of the system are: - Diagnosing the most probable degradation mechanism or mechanisms by reviewing the entire steam generator history; - Identifying the tubes most exposed to future damage and evaluating the urgency of repair by simulating the probable development of the problem in time; - Establishing the appropriate preventive actions such as repair, inspection or other measures and establishing an action schedule. The system is intended for utilities either for individual plans before each inspection outage or any time an incident occurs or for a set of plants through a central MPGV center