An approach to the quantification of seismic margins in nuclear power plants: The importance of BWR plant systems and functions to seismic margins

In NUREG/CR-4334 (''An Approach to the Quantification of Seismic Margins in Nuclear Power Plants''), the Expert Panel on Quantification of Seismic Margins presented a technique for studying the issue of quantifying seismic margins. As part of that technique, the panel included methods for simplifying the margins assessment by screening out components and systems using both systems and fragilities screening guidelines. At the time of that report, the panel was able to develop fragilities screening guidelines for all plants, however the systems screening guidelines applied only to PWRs (due to a shortage of BWR seismic PRAs upon which to base BWR systems screening guidelines). This report develops the BWR systems screening guidelines by utilizing the results of a number of BWR PRAs which have become available since the publication of NUREG/CR-4334