Risk informed optimization of instrumentation and control (I&C) architecture

The need of risk informed design approach for system, structure and components of nuclear facility has been realized, as it has features to identify weakness and determine an appropriate architecture with respect to safety and cost. In this study, we modified the risk informed design approach for I&C architecture to include multi-component risk importance along with other reliability, risk and optimization metrics. Few features of this approach are implemented on analog, digital and hybrid I&C configurations to perform optimization based on availability and reliability indices. Reliability parameters and optimization metrics are compared with those of reference architecture and International Electrotechnical Commission standard criteria. It is found that analog can yield higher level of availability with highest cost saving. However, the concern of obsolescence of analog I&C components makes it difficult option. Other competitor is hybrid configuration, which attains high level of availability compared to IEC criteria with rational cost saving and can be concluded as a feasible option.