Research and development of three-dimensional isolation system for SFR (Experimental study on static characteristics using half scale size model)

The seismic resistance of nuclear power plants, particularly those using Sodium-Cooled Fast Reactor (SFR) design, is of crucial significance. This paper presents an innovative three-dimensional seismic isolation system developed to address the inherent challenges of SFR design. Given that these designs necessitate components with a thin wall thickness for achieving high-temperature structural integrity, this can inadvertently lead to a disadvantageous seismic design. Hence, reducing seismic forces in both horizontal and vertical directions is crucial to ensure seismic resistance. This isolation system, designed for application to the reactor building, aims to make it an effectively isolated entity within the larger plant structure. It has been developed to manage seismic forces acting on components, thereby balancing the requirements of both seismic and high-temperature structural designs. The feasibility and effectiveness of this design have been verified through static loading tests conducted on a half-scale model of the system, investigating force-displacement relationships in both horizontal and vertical directions. The results demonstrate that the system's horizontal supporting function provides a stable load path. Additionally, it validates the decoupling of force-displacement interactions under the condition of simultaneous horizontal and vertical loading, an essential presumption in the formulation of the design basis ground motion.