Reactive chemical transport within engineered barriers

A technique to delay hydration and maturation of borehole seals of expansive clay

“…Once the seals are installed the clay will not be exposed to temperatures higher than some 50°C caused by the radioactive decay since the waste canisters will not be placed close to them (Pusch, 2008). Comprehensive theoretical and practical investigations of the mineralogical stability of smectites have shown that they will remain virtually intact for hundreds of thousands of years at this temperature (Pytte & Reynolds, 1989;Grindrod & Takase, 1993;Pusch & Ramqvist, 2006, Pusch, 2008. Talc is a magnesium silicate with very high chemical and thermal stability as documented by the mineral …”

Stiffening of smectite buffer clay by hydrothermal effects

“…A more recent version of the model that is relevant to the KBS-3 concept and gives quantitative data of quartz precipitation was proposed in the early nineties by Grindrod and Takase (Grindrod and Takase, 1994). In contrast to the conventional Pytte/Reynold-type models it does not preset smectite-to-illite as the basic reaction.…”

An Efficient Implementation of the Method of Lines for Multicomponent Reactive Transport Equations

“…Several recent works have shown that the GIA can be more efficient than the OS approach (Steefel and MacQuarrie 1996;Shen and Nikolaidis 1997;Saaltink et al 2001;Fahs et al 2008). In the last decade, the GIA has been increasingly implemented in numerical models for MRT simulations (for example, TOUGH2 (White 1995), GIMRT (Steefel and Yabusaki 1995), and ARASE (Grindrod and Takase 1996). The improvement of the GIA is currently a priority subject for modeling reactive transport problems (Saaltink et al 1998;Knabner 2005, 2007;Amir and Kern 2009).…”