Abstract
The paper describes an approach to obtaining prior imprecise reliability values of components and systems. The mathematical basis of the approach is the theory of coherent imprecise probabilities. The procedure of prior imprecise probability elicitation is based on analogical reasoning, and two cases of precise and imprecise reliabilities of prototypes are considered. Cases of combining different reliability judgements for the same component are analyzed. The remainder of the paper is devoted to imprecise reliability assessments of different system structures: components in parallel, in series and in series-parallel. The formulae obtained allow getting the lower and upper probabilities without the assumption of conditional independence. What we can expect from the use of this new tool is briefly discussed.