Study on Influence of Nonlinear Characteristics of Laminated Rubber Bearings on Reactor Buildings Including SMR

Abstract The development of small modular reactors (= SMR), which are safer and more rational than current nuclear power generation facilities, is underway. As a countermeasure against earthquakes, it is assumed that a laminated rubber bearing for seismic isolation system will be installed. It is well known that laminated rubber bearing has nonlinear mechanical properties in a large deformation region.[1] Therefore, searching for conditions where the effects of the nonlinear mechanical properties of laminated rubber bearing are likely to appear through modal analysis. Then, a nonlinear time history response analysis and a floor response spectrum are calculated for the selected conditions. The results will evaluate the effects of the nonlinear mechanical properties of laminated rubber bearing on reactor buildings and internal equipment. As a result of the evaluation, when the mass ratio of the base plate and the building is equal in the horizontal direction, the seismic isolation period is 2.00 s and the building vibration frequency is 4.00 Hz, and in the vertical direction, when the mass ratio is equal, the isolation frequency 20.0 Hz and the reactor building natural frequency 20.0 Hz, that was confirmed that the influence of nonlinear dynamic characteristics is noticeable.