Development of Level-1 PSA method for sodium-cooled fast reactors, 3; Development of response analysis method considering seismic isolation characteristics

Minagawa, Keisuke*; Fujita, Satoshi*; Yamaguchi, Akira*; Takata, Takashi*; Kurisaka, Kenichi 

In order to reduce the seismic load that is inputted into the reactor building and its internal components, adoption of an advanced seismic isolation system in the sodium-cooled fast reactor (SFR) is considered. Laminated rubber bearings have linear stiffness in the normal operation range. But as deformation increases, the bearings show non-linearity that causes hardening in the horizontal direction, and softening in the vertical. In this study, a simulation analysis was made to investigate an effect of the non-linearity on the building and internal components. In this analysis, the building was simulated with a mass-model and mechanical property of the bearings was simulated with multi-linear model. As a result, it was confirmed that (1) as the seismic load increases, the bearings indicate the hardening and it affects seismic response of the building, and that (2) a sensitivity of the seismic response to the parameters related to the bearings becomes high due to the hardening.