Prediction of Earthquake Frequencies at Sites of Nuclear Power Plants

摘要

One aspect of the Accident Initiation and Progression Analysis (AIPA) was to estimate earthquake occurrence frequencies at a representative HTGR site. This paper presents the results of the frequency assessments, compares them with the findings of other investigators, and presents some recommendations for further study. The model that was developed provides estimated occurrence frequencies of selected ground acceleration levels at individual sites of commercial nuclear power plants, based on appropriate data for each site. It also provides a measure of estimation uncertainty arising from limited data bases. The computed results indicate large uncertainties as determinable from both sampling uncertainty and site-to-site variabilities. The AIPA results for the Grand Gulf site indicate a smaller sampling uncertainty than that developed from a survey by Okrent, while the median frequency estimates for that site are about an order of magnitude apart. The average frequency estimates developed on the basis of the AIPA computational approach seem to be in reasonable agreement with the results of other investigators, including the Hsieh results. The fact that the Hsieh averages are somewhat higher than the AIPA averages does not seem unreasonable because the Hsieh averages appear to be primarily influenced by contributions from small geographic areas of high seismicity, areas that would tend to be avoided in the siting of commercial nuclear power plants. (ERA citation 03:047827)