Seismic Isolation for Advanced Fast Reactors

Abstract

We present the results of a survey of the state of seismic isolation technology. The emphasis of the review is placed in the United States. The purpose of this survey was to provide an engineering basis for the use of seismic isolation in the design of nuclear power plants. In particular, the survey is focused on providing a basis for the design of advanced fast reactor (AFR) nuclear power plants. These AFR plants typically have components and piping that are thin walled as opposed to the thick-walled components and piping in light water reactor (LWR) plants. As a result the AFR plants do not have the adequate inherent strength to resist seismic loads that exists in the LWR plants. It is far more desirable, therefore, to reduce the seismic demand on the AFR plants than to require costly measures to strengthen the structures and components. It is believed that the use of seismic isolation is a viable and effective way to provide this reduction in seismic demand. Various types of seismic isolation systems and devices are reviewed along with their strengths and weaknesses. Descriptions of several U.S. seismically isolated buildings are presented. The results of actual performance of seismically isolated buildings are also presented, including representative measurements of accelerations in the structures when subjected to actual seismic events. It is concluded that the seismic isolation technology is well established and that the path forward leading to the use of this technology for AFR nuclear power plants is clear and achievable.