the investigation about the impact of the vibration period change in the vertical isolation element

In this study, the investigation about the impact (: flexibility of the component design and possibility of the design rationalization) of the vibration period change in the vertical isolation element was carried out. Furthermore, the feasibility studies of the vertical isolation system and configuration of the vertical isolation system in the Fast Reactor Plants were examined. (1) The investigation about the impact of the vibration period change in the vertical isolation element. The possibility of the short period by reduction of the coned disk spring series number in this system was examined. The possibility of the reduction of the coned disk spring series number was confirmed. As the result, it was confirmed that rationalization of coned disk spring isolation element and that the damper and the supporting structure for the seismic horizontal force are compacted. Furthermore, the impact on configuration in the plant with the rationalization of the coned disk spring elements was examined. It was anticipated that the effect to common deck size by the coned disk spring diameter reduction was small and the effect of the rationalization by the configuration in the plant is also small. (2) Examination of the vertical isolation system. The examination about realization of the vertical isolation system was carried out for the sodium cooled medium size reactor plant. The common deck shape at the sodium medium size furnace is the following: A common deck height of 2.25m, 50m of steel plate board thickness, 301ton of a support weight of a coned disk spring. It is necessary to make weight imbalance of the common deck small, because the rocking vibration is affected by the weight imbalance. When the coned disk spring rigidity is increased, the displacement of vertical motion decreases but the displacement by the locking increases. The depression effect of the element displacement in vertical direction by the increase of the rigidity of coned disk spring can not be expected. The displacement difference of top and bottom of the common deck can be allowed to 25mm. (3) Plant arrangement examination. The configuration of the vertical isolation system in the Fast Reactor Plants was examined. As the result, it was possible to keep rate of increase of the building volume to 3.4% in comparison with the horizontal base isolation system condition.(author)