Ontology-based approach for analyzing nuclear overall I&C architectures

Nuclear power plants have many different instrumentation and control (I&C) systems. Together, these systems (and their various dependencies) form the overall I&C architecture, which needs to fulfill the principle of defence-in-depth. The safety systems need to be sufficiently independent from the normal operation systems to avoid common cause failure.Semantic Web technologies use formal conceptual models— ontologies—to associate meaning with unstructured data. The knowledge base is built on named graphs, allowing complex queries with reasoning. The results are based on more than just statistical patterns.In this paper, we demonstrate the use of an OWL ontology to represent engineering knowledge about overall nuclear I&C architectures. We show how, using flexible SPARQL queries, we can then analyse the different dependencies between the I&C systems. We have built a public case study based on a proposed pressurised water reactor type. We detected several potential design issues, which suggests the approach could improve nuclear safety and support design work.