A Survey on the Quantitative Evaluation Methods of Software Reliability of Digital I&C Systems at NPPs

The instrumentation and control (I&C) systems are important parts of the Nuclear Power Plants (NPPs). They are the key to safety, reliability and economic operation of the nuclear power generating units. With the development of systems at NPPs. Software reliability is important because software failure is usually considered as one form of common cause failures in digital I&C systems. The reliability analysis of the digital I&C systems, particularly quantitative evaluation on the software reliability analysis of the digital I&C systems belongs to a great challenge. This paper provides an overview of the ongoing research activities on a reliability analysis of digital I&C systems of NPPs, quantitative evaluation methods of software reliability, the advantages and disadvantages of the approaches, and research status at home and abroad. China is using the untraditional reliability analysis method of Multilevel Flow Model (MFM) to evaluate software reliability in digital I&C systems.