Seismic risk at NPP Cernavoda

The paper presents a brief description of the probabilistic analysis method employed to analyze a nuclear power plant (NPP) state during seismic events. For evaluating the seismic hazard at NPP Cernavoda, deterministic judgment are employed for determining the focus position, the attenuation of the seismic intensity and the local effects. The authors have designed a support device which can operate in damping regimes or as a snubber having also the function of non-linear elastic support with a progressive characteristic for permanent loads. This support can take over very great static and dynamics loads. The support and damping devices are hydro-pneumatic systems which completely eliminate the gaskets. The non-linear elastic supporting force is provided by compressing a volume of gas and the damping force is provided by a liquid flowing through a system of calibrated nozzles covered on one side or the other by a set of elastic blades of an imposed stiffness. The sizes and weight of the devices are under the ones of the current devices and they provide higher reliability. (Author)