Boolean Algebra Application in Simplifying Fault Tree Analysis

This paper discusses Boolean algebra applications in fault tree analysis. Fault tree analysis has been extensively used in nuclear power plant safety analysis, such as analysis of system hazard, determination of critical characteristics in commercial grade dedication, and estimation of industrial system reliability. In general, the logic relations presented in fault tree models can be equivalently represented in Boolean algebra formulas. The Boolean algebra representation has several advantages over the original fault tree representation. The most significant one is that the Boolean representation can easily be simplified to get a so-called minimum cut representation. From there, fault tree analysis can be applied to several applications mentioned above. In this paper, we use some simple examples to demonstrate how to use Boolean algebra as a tool to simplify the fault tree model to get an expression of minimum cut. We then point out possible applications of this technique, such as common mode failure using identical digital system/components and remedy by diversity design, hazard analysis, and critical characteristics determination.