Development of a Method for the Assessment of Modern I&C System Architectures with Regard to Failure Effects

Due to the reconstruction of new nuclear power plants (NPPs) and the retrofitting of existing facilities, more and more digital I&C systems are used for safety-important functions worldwide in NPPs. The structure, operation, and communication of digital I&C systems are strongly influenced by the implemented automatic failure detection and handling procedures (e.g. correction of certain failure types). Therefore, a new method for the sensitivity analysis and assessment of different I&C architectures has been developed to investigate the dynamic behavior of those systems in case of external errors. The paper presents results of the sensitivity analysis for some typical example architectures showing that this method can support the verification and validation activities on the design and operation of digital I&C systems at an early stage. (author)