A probabilistic approach to evaluating the risk of future volcanism for a potential underground repository for disposal of high-level radioactive waste was developed for the Yucca Mountain Site Characterization Project (YMP) in the early 1980's. Extensive interactions with program participants, regulatory agencies and the State of Nevada provide a perspective for assessing the utility o f probabilistic risk assessment applied to a controversial issue. The risk of future volcanism from disruption of a repository is evaluated as a conditional probability: Pr_(volcanic risk) chemical bounds Pr(E3 given E2)Pr(E2 given E1)Pr(E1) where E3 is the probability of radiological rleases to the accessible enviroment from magmentic activity (eruptive and/or intrusive volcanic events), E2 is the probability of intersection of a specified area, and E1 is the recurrrence rate of volcanice envents. This conditional probability is applied iteratively to programmatic decisions for two topics: 1) the risk soletly from the effects of future volcanism on a repository (suitability issue) and 2) risk from couled effects of future eruptive and intrustive magmentic events on the waste isolation system (compliance issue).
展开▼
