A review on the research status of reliability analysis of the digital instrument and control system in NPPs

Abstract

Abstract The widely use of digital instrument and control (I&C) systems in nuclear power plants (NPPs) and their important role in plant safety put forward the requirement for developing reliability modeling for digital systems with the capacity to be integrated into the existing probabilistic safety analysis (PSA) framework. However, challenges arise in the reliability analysis which mainly come from the modeling of complex interactions among the system hardware, software, controlled process physics, and operator. Generally, these factors are analyzed separately since at present there isn’t universal methods for modeling them in a uniform framework. In this paper, the research status of reliability modeling methodologies, software reliability assessment methods and human reliability analysis for digital instrument and control systems in NPPs were introduced. The survey results show that ET/FT is still the mainstream method in reliability studies of digital systems in NPPs, and DFM is a dynamic method with great potential. At present, there is no generally accepted software reliability analysis method. The researches about human errors under digital environment and the theoretical basis of corresponding human reliability analysis method is being developed.