Development of the evaluation methodology for earthquake resistance of the engineered barrier system(II)

Mori, Koji*; Neyama, Atsushi*; Shirakawa, Toshihiko*

JNC TJ8400 99-080, 149 Pages, 1999/02

JNC-TJ8400-99-080.pdf:10.38MB

In this study, the following several tasks have been performed in order to evaluate the stability of earthquake resistance for the engineered barrier system of High Level Waste(HLW) geological isolation system. (1)Based on the wave propagation theory for one-dimensional multi-layer system, we have estimated the underground seismic wave that propagates in the HLW repository site. This analysis was based upon the JNC Virtual Geological Model and we used the E1-Centro earthquake data as the surface observed wave. Through this inversion analysis, we have found that this interest geological model has the about 60%(G.L.-1000m) and 20%(G.L.-500m) decreasing ratio of the acceleration to the surface observed acceleration level. (2)Since 1992 we have developed the three dimensional seismic response analysis code for the engineered barrier system, which based on Finite Element Methodology. This analysis code has various function to take into consideration ae realistic repository system(e.g. material nonlinear models, joint crack element and infinite viscous boundary element). We have made the study of the concrete analysis method designed to the near field seismic response analysis, through the sensitivity analysis using above various function. Based on these studies, we have evaluated the earthquake resistance stability for the near-field repository system. Two types of disposal concept were considered as the reference case associated with the JNC second progress report. Through this study, we have concluded that the shear stress due to earthquake in the buffer material is very small relative to that due to the earth load and the earthquake resistance stability will be maintained.