Hydraulic characteristics of buffer material-II; The influence which saline water exert on hydraulic properties of bentonite buffer material

Kikuchi, Hirohito*; Tanai, Kenji; Matsumoto, Kazuhiro*; Sato, Haruo; Ueno, Kenichi; Tetsu, Takeshi*

JNC TN8430 2003-002, 47 Pages, 2003/03

JNC-TN8430-2003-002.pdf:2.11MB

By the second progress report(H12) on research and development for the geological disposal of HLW in Japan, Japan Nuclear Cycle Development Institute (JNC) extended the database on basic properties of compacted bentonite, and this was mainly obtained by using distilled water as test fluid. This report presents influence of dry densities, silica sand content and temperature on the hydraulic properties of compacted bentonite under condition of marine-based groundwater, which was simulated by use of synthesized seawater. We found that hydraulic conductivity increases with increasing temperature, and the relationship between effective clay density and intrinsic permeability is obtained by the following equation. = exp(-47.155 + 15.138 -7.878 ) where is intrinsic permeability[m], is effective clay density[Mg/m]. Intrinsic permeability using synthetic seawater as test fluid is about ten times higher then that under distilled water condition. Difference between them however becomes smaller with increasing dry density. We also examined the smectite layers distance after test samples, but remarkable change was not found between them.