ASCE 4 Provisions for Seismic Isolation of Safety-Related Nuclear Structures

Seismic isolation is a viable method of protecting nuclear safety-related structures from the damaging effects of earthquake shaking. The soon-to-be completed 2013 edition of ASCE Standard 4 will include detailed provisions and commentary (Section 7.7) to enable the horizontal seismic isolation of nuclear facilities such as nuclear power reactors and waste storage facilities. Although the provisions and commentary focus on building-type structures, they can be applied, in principle, to other structures, systems, and components, including small modular reactors and safety-related systems such as diesel generators. The performance expectations associated with the provisions, and their integration with ASCE 43-05, are presented together with the design basis for the isolated superstructure and safety-related secondary systems, the isolators, the foundation and the umbilical lines that cross the isolation interface.