Instrumentation and Control (I&C) Systems important to safety must conform to their requirements, where regulatory requirements are first class entities, written by national safety authorities and completed using a set of national recommendation guides or standards. The global domain knowledge is scattered, not formalized and traceability links and the organization within the domain are implicit. Bridges between different national practices are not developed, whereas the understanding of requirements and practices variability concerns becomes a significant industrial issue. The thesis sets up in an industrial context with EDF R&D and the CONNEXION project that gathered the French nuclear I&C industry. Its contributions are defined around th...