New seismic design spectra for nuclear power plants

Under a US Nuclear Regulatory Commission-sponsored project recommendations for seismic design ground motions for nuclear facilities are being developed. These recommendations will take several forms. Spectral shapes will be developed empirically and augmented as necessary by analytical models. Alternative methods of scaling the recommended shapes will be included that use a procedure that integrates over fragility curves to obtain approximately consistent risk at all sites. Site-specific soil effects will be taken into account by recommending site-specific analyses that can be used to modify rock hazard curves at a site. Also, ii database of strong motion records will be archived tor the project, along with recommendations on the development of artificial motions. This will aid the generation of motions for detailed soil- and structural-response studies.