An evaluation method for seismic isolation effect in siting of a nuclear facility

Seismic reliability is one of the most appropriate indices to compare several site/design alternatives of important facilities from the viewpoint of seismic safety. A method is demonstrated here to compare seismic reliabilities of two buildings, with and without seismic base isolation, unbiasedly. Particular attentions are paid for ground motion characteristics and nonlinear load deformation relationships to avoid biases. thod is applied to an example of siting/design issues, situation of which is similar to an experimental fusion facility. Reference buildings are simply modeled and their annual probabilities of failure are evaluated. It is confirmed that an unbiased comparison between base isolated and non-base isolated buildings is reasonably possible. It is also confirmed in terms of reliability that introducing seismic base isolation system is an effective means for siting/design issues.