Advanced seismic isolation system

For seismic design, JSFR adopts an advanced seismic isolation system for SFR that mitigates the horizontal seismic force by thicker laminated rubber bearings with a longer period and the improvement of damping performance by adopting oil dampers (Okamura, 2011). 

Commission of Japan, 2006). Hence, the demonstration reactor of JSFR must adopt an advanced seismic isolation system, which is a practicable modification of previous technologies, because the earthquake force that affects the primary components must be mitigated more than that of the previous seismic isolation system. 

The advanced seismic isolation system for SFRs adopts laminated rubber bearings, which are thicker than those of the previous design, as well as oil dampers. As a result of the examination, the specification of the advanced seismic isolation system for SFRs is that the natural frequency in the horizontal direction is 0.29 Hz and in the vertical direction it is 8.0 Hz (Okamura et al., 2011). 

Cancellara D., De Angelis F. (2012)—Seismic analysis and comparison of different base isolation systems for a multi-storey RC building with irregularities in plan. Advanced Materials Research, Vol. 594-597, pp. 1788-1799. 

Ziegler, F., Khalid, B. (2011). A novel base isolation system for as5mimetric buildings in seismic active zones damping supplied by tuned liquid column-gas dampers. In Belyaev, A. K., Irschik, H., Krommer, M. (Eds.), Advanced dynamics and model based control of structures and machines (pp. 225-234). Wien, Austria Springer-Verlag. doi 10.1007/978-3-7091-0797-3 26... 

These measures are expected to be more realistic by introducing some innovative technologies such as Mod.9Cr-lMo steel with high strength at high temperatures, advanced elevated temperature structural design standards, two-dimensional seismic isolation, and a re-criticality free core as well as by taking the desirable characteristics of sodium coolant such as operability in a low-pressure system and excellent heat transfer characteristics into account. 

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