Analytical Study on Vertical Response Behavior of Fast Reactor Plant with Three-dimensional Seismic Isolation System during Severe Earthquake

Abstract

The seismic design is important for the SFR(:Sodium-cooled Fast Reactor). Not only the decrease of the horizontal seismic load but also the decrease of the vertical seismic load is necessary in the severe seismic condition. Accordingly, the three-dimensional seismic isolation system is developed for the SFR. This system was designed with a horizontal natural frequency of 0.294 Hz and a vertical natural frequency of 3 Hz. This system consists of thick rubber bearings, coned disc springs, and oil dampers. The static test in these elements of this system was carried out. The investigation of seismic PRA in the SFR with this system is necessary. In this study, the analytic examination on the vertical response behavior during severe earthquake is carried out. In this report, the analysis model with the mechanical characteristic, which is provided in the element test, is investigated. The time history response analysis with this model is carried out during severe earthquake. The response of components is approximately linear in the input seismic load. The extreme response increase of components hardly is confirmed. As a result, the reliability of this system is confirmed.