In the high-level radioactive waste disposal project, in order to know the infiltration behavior, it have to be examined that the bentonite buffer material is used as a barrier, and the measuring device of moisture with the high accuracy is required. In this study it is discussed the usefulness for Frequency Domain Refrectometry (FDR) method through the measuring dielectric constant and making the calibration curve for the several kinds of bentonite material block (pure and silica sand mixing)
