The colloid and radionuclide retardation experiment at the Grimsel Test Site: influence of bentonite colloids on radionuclide migration in a fractured rock

Montmorillonite colloids: I. Characterization and stability of dispersions with different size fractions

“…In the present case, we tend to the composition of the granitic groundwater coming from the Grimsel Test Site (Möri et al, 2003;Geckeis et al, 2004). This is done by mixing the requested amounts of the different salts (NaOH, NaCl, CaCl 2 , MgCl 2 , NaF, Na 2 SO 4 and NaHCO 3 ) and an aliquot of the Si standard solution in ultra-pure water.…”

“…In case of large mass loss, the buffer functionality will be endangered. Also, in the case of a canister failure, the transport of RNs can be enhanced, when transported by mobile montmorillonite colloids (Möri et al, 2003).…”

Review on subsurface colloids and colloid-associated contaminant transport in saturated porous media

“…Complexes with organic matter can result in humic colloids that are transported under favorable conditions of solution composition and water content [164 -167]. Contardi et al [168], have shown that inclusion of colloids into a conceptual model of contaminant transport can result in a several order of magnitude reduction in the retardation factor for strongly retained ions like Am and Th, Mori et al [157] have shown from their laboratory column experiments that migration behavior of the tri and tetravalent actinides Am and Pu was strongly mediated by the bentonite colloids. Colloidmediated Pu transport in groundwater has been reported by Kersting et al [5].…”

“…Magaritz et al [191] were able to show that the metals associated with the colloid fraction recovered in their passive groundwater samplers were enriched relative to the metal content of the surrounding sediment. Mori et al [157] have presented the results of the colloid and radionuclide retardation (CRR) experiment for in situ migration behavior of selected actinides and fission products in the absence and presence of bentonite colloids in fractured rock at nagra's Grimsel Test Site (GTS) in the central Swiss Alps. Bentonite colloids were stable in the groundwater and the in situ monitored breakthrough of the tri and tetravalent actinides Am and Pu and Cs followed the colloid breakthrough indicating some degree of colloidmediated migration of these radionuclides in the experimental shear zone.…”

The tritiated water and iodine migration in situ in Grimsel granodiorite. Part I: determination of the diffusion profiles

“…matrix diffusion) and sorption onto the mineral surfaces are the most significant processes that retard RNs flowing through fractures [6][7][8]. Diffusion and sorption of RNs have been studied extensively in the laboratory [9][10][11][12] but very few studies have been carried out using in situ experiments, especially with RNs [13][14][15]. One of the main reasons for this is that these experiments are time consuming, cost intensive and require special legislation if RNs are used.…”