Comparative analyses of a nuclear island on linear and non-linear aseismic bearing pads

Seismic foundation isolation schemes are an attractive solution for the design of nuclear power plants in seismic areas. By reducing the horizontal accelerations, especially in the high frequency range, they allow the use of standardized design on sites with significant seismicity. Two solutions have been adopted to date to isolate the most important buildings of nuclear power plants during a postulated Safe Shutdown Earthquake (SSE). The first isolation scheme which was utilized in France (Cruas Nuclear Power Plant) includes elastomer bearing pads while the second scheme (used at the Koeberg Nuclear Power Plant in South Africa) also comprises sliding elements. The paper presents a comparison between these two isolation schemes for which dynamic analyses were performed as part of the feasibility study of a nuclear power plant to be designed for a peak ground acceleration of 0.26 g. (orig./HP)