Study of vibration behavior of deep underground cavity and internal structure (2); Cooperative project of JNC with National Research Institute for Earth Science and Disaster Prevention Science and Technology Agency

Taniguchi, Wataru ; Takachi, Kazuhiko; not registered; Mori, Koji*

In Japan, where many earthquakes have been occurring, it's very important to evaluate aseismatic mechanical stability of the engineered barrier system (EBS) of high-level radioactive waste (HLW) repository. In this study as a cooperative project of JNC with National Research Institute for Earth Science and Disaster Prevention Science and Technology Agency, that started from 1992, aseismatic mechanical stability of the EBS of HLW repository have been evaluated based on the engineering scale vibration test of the engineered barrier and the analytical methods. In this report, the results of the engineering scale vibration test of the engineered barrier and the development of the analytical computer code for seismic response of the engineered barriers are described, following Study of Vibration Behavior Deep Underground Cavity and Internal Structure (1). From this study, the following conclusions are obtained (1)Engineering scale vibration test of engineered barrier. From the results of sweep wave vibration tests conducted to examine the effect of natural frequency of the EBS, the natural frequency of the EBS tends to decrease as the acceleration increases. From the results of vibration tests with the actual seismic waves characteristics, both of the simulated overpack and the buffer have no significant response against seismic and then simulated engineered barriers behave dynamically as a rigid body. (2)Development of the analytical computer code for seismic response of the engineered barrier. The analytical computer code has been developed considering the non-linear dynamic properties of the buffer material between stress and strain. verification analysis results for the engineering scale vibration test of the engineered barrier mentioned above, using the analytical computer code, agree with vibration test of the engineered barrier.