Application of goal trees to evaluation of the impact of information upon plant availability

Development of a comprehensive risk management program for a nuclear plant owner requires that an integrating framework be devised to provide not only identification of all the discrete contributors to risk, but also an understanding of the ways in which they contribute. It is this understanding which enables the owner to effectively evaluate all potentially feasible schemes to be employed in maintaining overall risk at an acceptable or optimal level. The authors describe how a goal tree can prove useful in providing this required degree of understanding. The results of numerous risk assessments would seem to indicate that improvement in human performance provides better potential for risk reduction than does improvement in hardware performance. The focus here is on a process to evaluate the benefits which accrue from improvements in informational systems. In this report a rigorous and quantitative approach is described for information and its worth in improving equipment availability, particularly in the area of equipment protection