Study on Vibration Deadening of Double Pipe-Filled Bead for Primary Piping System in Fast Breeder Reactor

Abstract

There are a lot of earthquakes in Japan. For this reason, it is very important to evaluate the soundness of piping of a nuclear power plant for adequate safety of seismic design. Additionally, piping in nuclear power plant confronts the effect of aging. The object of this study is to clarify relations between damping characteristics of piping and several conditions of pipe. In this study, thickness of pipe test, support type test, damaged pipe test and double pipe-filled glass bead test were conducted with impact system. The results obtained through the study are as follows; (1)Pipe thickness and support type contribute to the damping characteristics of pipe.(2)Damaged pipe don't affect the damping, but the frequency of pipe decrease as damage grew. (3)Double co-axial pipe has high damping ratio. Especially, the damping ratio when glass bead are filled between the inner pipe and outer pipe is about 10%.