Accident Analysis of Complex Systems Based on System Control for Safety

Abstract

In modern complex systems such as chemical and nuclear plants, as its hardware system reliability increases due to the advancement of technology, systemic failures such as software design errors become a significant contributor to system accidents. State-of-the-art computers have made many technology-based systems so complex that new types of accidents now result from dysfunctional interactions between system components, further adding to the number of accidents resulting from component failure. Other factors, such as management effectiveness and organizational constraints, must also be considered as part of a failure prevention strategy. Conventional event-based analysis methods such as fault trees cannot be always applied to such types of accidents. This chapter applies a concept of system control for safety to the accident analysis in two ways. The first part deals with accident cause analysis, while the second part deals with the accident analysis in the defense-in-depth approach.