Development of seismic counter measures against cliff edges for enhancement of comprehensive safety of nuclear power plants; A Study for nuclear building system

Nishida, Akemi  ; Choi, B.  ; Guo, Z.; Takada, Tsuyoshi*  

In this research, the seismic safety of a nuclear power plant (NPP) is treated as a system in which the various cliff edge effects are identified and quantified based on the concepts of risk and defense in depth. A methodology is then developed for avoiding these cliff edge effects. In order to examine how the cliff edge state specified in the seismic response analysis of the building system depends on the modeling factor, we investigated the seismic isolation mechanism and the modeling of the boundary condition of the retaining wall collision event, etc. In this paper, we describe these results and discuss about them.