INVESTIGATION ON ULTIMATE STRENGTH EVALUATION OF SNUBBER IN PIPING SYSTEM OF JAPANESE NPP

摘要

It is confirmed that strength of snubbers which have been used in piping systems of apanese NPP, are one and a half times as strong as one's fixed capacity. However, it is expected that snubbers have above two times strength of one's fixed capacity.In this study, destructive experiments were conducted, ultimate strength evaluation of snubber was accomplished. This study was carried out by 10 apanese utilities and 3 plant manufacturers as joint research.Snubbers consist of functional elements such a pipette valve except strong elements. It is needed to confirmwhether their functional elements preserve one's functions for seismic load in the case of evaluating ultimatestrength of snubber. Therefore, destructive experiments were conducted for snubbers used in piping systems ofapanese NPP from a point of functional preservation. Further more, destructive experiments were conducted from apoint of buckling.Based on the experimental results, ultimate strength evaluation of snubber have been investigated, according to study on differences between ultimate strength obtained by destructive experiments and expected ultimate strength based on the strength of materials.