Reliability analysis of nuclear fail-safe redundancy

In many critical nuclear safety system applications, fault tolerance has been an essential design attribute for achieving high reliability. Generally, operating systems cannot achieve the intended reliability without employing redundancy. Redundant systems, however, require additional resources in terms of both labor and materials. Therefore, the redundancy level needed to achieve fault tolerance must be carefully determined by balancing the reliability and the cost of the systems. In this paper, the optimization problem is formulated and solved for the minimum average total cost of nuclear fail-safe systems. We also determine the optimal system size which minimizes the average total system cost subject to a restricted type I design error. Application and numerical examples are given to illustrate the results.