Research and development of thick rubber bearing for SFR (Design formulas for thick rubber bearing based on static loading test utilized scale model)

Abstract

This paper describes design formulas and creep characteristics for thick rubber bearing applied to the Sodium-cooled Fast Reactor, which are based on the static loading test and creep test using scale models. The thick rubber bearing, which has a rubber layer roughly two times thicker in comparison with conventional rubber bearings, has been developed by the authors to ensure seismic safety margins for components by reducing the seismic response for the reactor building in the horizontal direction and vertical direction. The static loading tests using a scale model with parameter of first shape factor were conducted to investigate the applicability of proposed design formulas. Moreover, an estimation of creep characteristics due to aging is important issue because the rubber layer of thick rubber bearing which satisfies the design requirement for SFR is larger than conventional rubber layer. The creep test was preformed to estimate the creep characteristics using a scale model. From the above results, the thick rubber bearing is sufficiently rational for use as isolation system for SFR.