Summary of the historical development of seismic design of nuclear power plants in Japan and the U.S.

Over the past 50 years seismic design of nuclear power plants in Japan and the U.S. have undergone very significant changes in the three activities associated with design:
• Quantification of seismic load and other applicable loads and specification of their load combinations to be considered in design.
• Analysis methods and procedures necessary to convert input earthquake motions and loads normally expressed in the form of acceleration to resultant seismic dynamic or equivalent static forces, moments or stresses, fms in structures, systems and components, SSC.
• Codes or standards acceptance criteria used to evaluate resultant forces, moments or stresses, fms in nuclear safety SSC to determine design adequacy.These applications to the historical development of Nuclear Power Plant, NPP designs in Japan and U.S. are summarized.