Knowledge engineering as a support for decision making in plant operation and maintenance

Electricite de France (EDF) considers the preservation of expert know-how as a major issue, especially in the field of nuclear power plant operation and maintenance. This can be related to the growing interest corporate knowledge management has encountered during the past years, but is basically due to the key role played by expert knowledge and know-how in plant operation and maintenance tasks. Furthermore, in the past fifteen years a significant amount of work has been devoted to the development of knowledge-based systems for the diagnosis and maintenance support of plant components. During this period, several various needs have emerged from the field of plant operation and maintenance. As most of these needs appeared to be based on the exploitation of technical knowledge and know-how achieved by EDF operational experts during the past years, we focused our work on knowledge modeling and reuse. This paper presents a general knowledge based system design approach derived from our past experience in the development of knowledge-based solutions for troubleshooting and maintenance support that meet plant operators' needs. Our goal is to provide them with automated operation or maintenance assistance. This approach is targeted at sharing and using expertise on technical fields. It relies on the use of models as an efficient supporting framework for knowledge acquisition and knowledge reuse (via the implementation of operational tools that make knowledge available to others and facilitate knowledge maintenance and consistency). This provided assistance relies on services that have been applied for diagnosis and predictive maintenance for such components as reactor coolant pumps or turbine-generators. Services range from reference-knowledge browsing to health assessment, diagnosis or maintenance schedule analysis; these are available as web internet services and are implemented using the eKCM software environment (eKnowlege for Competitive Maintenance) that has been jointly developed by EDF and Sharing Knowledge a software company. This article highlights the rationales that led us to use knowledge engineering - and distributed knowledge based systems - to support plant operation and maintenance; it will present the modeling and application design methodology, the unified framework and the associated software framework we developed to formalize, express and process expert knowledge and know-how; it focuses on some significant operational examples such as condition-based maintenance, life cycle management or plant decommissioning. This paper will also describe the way our solutions can be integrated in operational activities and the associated benefits. The article will expose the way we conduct such knowledge management projects to efficiently manage expert knowledge and to develop adapted operational tools. (author)