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U.S. Department of Energy
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Evaluating the effects of seismic events on systems in a nuclear facility using the. sigma. PI method

Technical Report ·
OSTI ID:6363590

This report describes an application of the ..sigma..-PI method to a seismic safety problem. The ..sigma..-PI method is a very recent advance in probabilistic modeling and computation. It simplifies the computation of failure probabilities of large systems such as power plant systems in the seismic safety problem which SEISIM, an existing model, evaluates. For such systems, using no more computer resources, ..sigma..-PI calculates estimates of system failure probabilities, whereas SEISIM calculates upper bounds to its estimators of the same probabilities. ..sigma..-PI is actually two methods, ..sigma.. and PI. PI is a modeling technique which leads to fast and accurate calculations of cut set probability estimators. PI can evaluate large cut sets of dependent basic events without difficulty, whereas SEISIM is drastically limited by the rapid acceleration of computer requirements with respect to cut set size. The ..sigma..-PI method described in this report has been implemented and tested and is now available for merging with existing seismic safety computer codes.

Research Organization:
Lawrence Livermore National Lab., CA (USA)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
6363590
Report Number(s):
UCID-19810; ON: DE83013705
Country of Publication:
United States
Language:
English