Modelling and quantification of testing, maintenance and calibration errors in system analysis and risk assessment

摘要

general equations are developed for quantification of the probabilities of combinations of sequentially dependent human errors asspciated with testing, maintenance or calibration (sometimes called "pre-accident" or "pre-initiator" tasks) of redundant safety systes. Specific guidance is presented for incorporating these dependent events in large system analysis. Exact implicit and explicit methods are described as well as some approximate analytical methods. The results show that some hidden or arbitrary assumptions and other weaknesses are present in earlier methods and guides.