A seismic margin methodology for assessing existing DOE facilities beyond design basis

摘要

For evaluation of existing DOE facilities subjected to seismic hazards, the seismic hazard assessment is often out of date relative to the current state of the art. Another problem frequently associated with seismic evaluation of existingfacilities is that design information is either non-existing or inadequate. As a result, assumptions based on best judgment have to be made in order to conduct the evaluation. Due to the additional uncertainties associated with existing facilities in theseismic evaluation of existing facilities, it is often required to look beyond the design basis. Two methodologies are considered acceptable to identify potential seismic vulnerabilities of existing facilities beyond the design basis. The first is aseismic probabilistic risk assessment and the second is one of the seismic margin methodologies. The seismic margin approach is usually more cost effective as compared with the seismic probabilistic risk assessment. This paper describes a seismic marginmethodology which can be applied to most existing DOE facilities in the Central and Eastern United States.