Plant modification: Applying human reliability analysis to the risk assessment of McGuire Nuclear Station

The risk assessment of Duke Power Company's McGuire Nuclear Station, Unit 1, is a full-plant, integrated analysis. Such an analysis must necessarily consider the effects of operators in their role as incident managers and estimate the current level of plant operational reliability toward protecting the reactor core and the public. Findings from such an analysis, irrespective of numerical aspects, can directly lead to enhanced plant safety and reliability through modifications to procedures and plant practices. These ''soft'' changes are typically less costly, yet may be as beneficial to the plant as major hardware changes. This paper focuses on two examples of how human reliability analysis led directly to procedural or policy modifications. Further, these examples may serve to show that significant information and plant understanding can follow from an analysis that considers the role of operators in incident response. This gain is irrespective of the particular HRA techniques used. Numerical results will not be presented, since they would be misleading outside the full risk context. However, sequences cited can be assumed to have been assessed as relatively important to McGuire's safety or core protection reliability