Inverted relation between stabilities of secondary minerals and alteration rate of montmorillonite in chemistry/mass-transport coupled analyses of cement/bentonite engineered barrier system for TRU-2 report

Honda, Akira; Yamaguchi, Kohei*; Oda, Chie  

More significant alteration of montmorillonite was estimated if the precipitation of meta-stable as opposed to stable secondary minerals was assumed in a chemical/mass-transport coupled analyses of cement/bentonite engineered barrier system for TRU-2. In general, this tendency is reversal. In order to understand the reason of this reversal tendency, geochemical calculations of batch system were conducted. The S.I. of montmorillonite is lower in the case of meta-stable secondary minerals, except for the very short initial period. Because the S.I. of montmorillonite is higher throughout most of the reaction period in the case of meta-stable secondary minerals, the alteration is more significant.