The report presents the historical development of the seismic design for the U.S., France and Sweden with special focus on issues related to severe earthquakes beyond the design basis as well as important aspects concerning the design basis ground motions for the Swedish nuclear facilities.
The report provides recommendations on a revised model for seismic hazard assessments, on minimum requirements for seismic analysis of safety-related nuclear structures in Sweden as well as some recommendations for new structural design or redesign of existing structures. It also provides a proposal to address seismic margin assessments for severe earthquakes beyond the design basis.
The detailed recommendations on minimum requirements and safety assessments are focused on the safety-related building structures