FIRE PRA ADVANCEMENTS IN ESTIMATING THE LIKELIHOOD OF FIRE-INDUCED SPURIOUS OPERATIONS

摘要

Two projects utilizing expert judgment have been carried out recently that focus on the qualitative and quantitative aspects of hot short-induced spurious operation of equipment as a result of fire damage to electrical cables within a nuclear power plant (NPP). This paper summarizes the efforts and reports the main results obtained so far. Both projects were under the direction of Brookhaven National Laboratory. The first project engaged a group of electrical experts to construct a Phenomena Identification and Ranking Table (PIRT) with the objective of using expert judgment to identify and rank the parameters that influence fire-induced cable damage. The results of this panel provided technical consensus on several contentious safety issues related to fire-PRA electrical circuit analyses. Specifically, the PIRT results categorized circuit configurations as being possible, implausible or incredible; which provided strong technical recommendations to support regulatory activities. Additionally, the results of the PIRT panel identified areas where knowledge is low and suggested areas of future research prioritized on risk insights. A second project involved a group of fire PRA experts with the goal of using expert judgment for quantifying probabilities and durations of hot short-induced spurious operations caused by fire damage to electrical cables. The later project applied the Senior Seismic Hazard Analysis Committee (SSHAC) process, so the results obtained are expected to represent the opinion of the relevant informed technical community. These results are mainly aimed for performance-based applications.