1986 年 28 巻 4 号 p. 337-343
A coaxial double-pipe structure is to be used in both the main and auxiliary primary coolant systems of the very high-temperature gas-cooled reactor which has been developed by Japan Atomic Energy Research Institute. By using a straight-type model of the coaxial double-pipe structure, the experiment has been carried out to study the following items: Effect of both the pitch of spacers in the axial direction and insulator inserted into the inner pipe on the damping vibration characteristics. These experimental results are compared with calculated values for a parallel-beam model using a structural analysis code COSMOS-7. The followings are the conclusions derived: (1) Damping ratio of a coaxial double-pipe structure increase with decrease of the pitch of spacers in the axial direction. (2) The calculated results of displacement-time response against the impact force almost agree with the experimental ones.