In situ diffusion experiment in granite: Phase I

ABSTRACTMatrix diffusion is a key process for radionuclide retention in crystalline rocks. Within the LTD project (Long-Term Diffusion), an in-situ diffusion experiment in unaltered non-fractured granite was performed at the Grimsel Test Site (www.grimsel.com, Switzerland). The tracers included 3H as HTO, 22Na+, 134Cs+ and 131I- with stable I- as carrier.The dataset (except for 131I- because of complete decay) was analyzed with different diffusion-sorption models by different teams (NAGRA / IDAEA-CSIC, UJV-Rez, JAEA, Univ. Poitiers) using different codes, with the goal of obtaining effective diffusion coefficients (De) and porosity (ϕ) or rock capacity (α) values. A Borehole Disturbed Zone (BDZ), which was observed in the rock profile data for 22Na+ and 134Cs+, had to be taken into account to fit the experimental observations. The extension of the BDZ (1-2 mm) was about the same magnitude as the mean grain size of the quartz and feldspar grains.De and α values for the different tracers in the BDZ are larger than the respective values in the bulk rock. Capacity factors in the bulk rock are largest for Cs+ (strong sorption) and smallest for 3H (no sorption). However, 3H seems to display large α values in the BDZ. This phenomenon will be investigated in more detail in a second test starting in 2013.

Download Full-text

A fully 3-D anisotropic numerical model of the DI-B in situ diffusion experiment in the Opalinus clay formation

Physics and Chemistry of the Earth Parts A/B/C ◽

10.1016/j.pce.2006.04.017 ◽

2006 ◽

Vol 31 (10-14) ◽

pp. 531-540 ◽

Cited By ~ 30

Author(s):

J. Samper ◽

C. Yang ◽

A. Naves ◽

A. Yllera ◽

A. Hernández ◽

...

Keyword(s):

Numerical Model ◽

Opalinus Clay ◽

Diffusion Experiment ◽

In Situ Diffusion ◽

Clay Formation

Download Full-text

In-Situ Diffusion Experiment In Sparsely Fractured Granite

MRS Proceedings ◽

10.1557/proc-824-cc7.4 ◽

2004 ◽

Vol 824 ◽

Cited By ~ 1

Author(s):

Peter Vilks ◽

Neil H. Miller ◽

Mark Jensen

Keyword(s):

Field Experiments ◽

Effective Diffusion ◽

Rock Properties ◽

Experimental Program ◽

Diffusion Experiment ◽

Stress Regime ◽

In Situ Experiments ◽

In Situ Diffusion ◽

Conservative Values

AbstractThe in-situ diffusion experiment was conducted at AECL's Underground Research Laboratory (URL) to improve the understanding of diffusive solute transport in sparsely fractured or intact granitic rock (SFR). The experimental program used a comparative series of laboratory and in-situ field experiments to evaluate the ability of laboratory measurements to estimate in-situ rock properties and to explore issues surrounding the influence of stress relaxation, rock texture, porosity, pore geometry, and anisotropy on derived effective diffusion coefficients (De). In-situ experiments yielded iodide Debetween 1.4 × 10−13 and 1.1 × 10−12 m2/s. Unlike laboratory results, the in-situ De estimates did not exhibit correlation with sample depth or varied stress regime. Laboratory-derived measurements of De, porosity and permeability were found to systematically increase for samples removed from greater depths and higher stress regimes. Laboratory-derived iodide De values consistently trended higher than in-situ values by a factor of 1 to 15, except on the shallowest 240-m Level (σ1 ≍ 30 MPa) where differences were negligible. Laboratory-derived estimates of permeability were consistently higher than in-situ derived values by a factor of 2 to 100. This experimental program provides evidence that laboratory steady-state diffusion experiments are most likely to yield conservative values of De for simulation of diffusive mass transport in SFR.

Download Full-text

Comparative modeling of an in situ diffusion experiment in granite at the Grimsel Test Site

Journal of Contaminant Hydrology ◽

10.1016/j.jconhyd.2015.06.002 ◽

2015 ◽

Vol 179 ◽

pp. 89-101 ◽

Cited By ~ 29

Author(s):

Josep M. Soler ◽

Jiri Landa ◽

Vaclava Havlova ◽

Yukio Tachi ◽

Takanori Ebina ◽

...

Keyword(s):

Comparative Modeling ◽

Test Site ◽

Diffusion Experiment ◽

Grimsel Test Site ◽

In Situ Diffusion

Download Full-text

The DR-A in-situ diffusion experiment at Mont Terri: Effects of changing salinity on diffusion and retention properties.

MRS Proceedings ◽

10.1557/opl.2014.629 ◽

2014 ◽

Vol 1665 ◽

pp. 63-69 ◽

Cited By ~ 3

Author(s):

Josep M. Soler ◽

Olivier X. Leupin ◽

Thomas Gimmi ◽

Luc R. Van Loon

Keyword(s):

British Columbia ◽

Reactive Transport ◽

High Salinity ◽

Transport Modeling ◽

Reactive Transport Modeling ◽

Diffusion Experiment ◽

Predictive Capability ◽

In Situ Diffusion ◽

Mont Terri

ABSTRACTIn the new DR-A in-situ diffusion experiment at Mont Terri, a perturbation (replacement of the initial synthetic porewater in the borehole with a high-salinity solution) has been induced to study the effects on solute transport and retention, and more importantly, to test the predictive capability of reactive transport codes. Reactive transport modeling is being performed by different teams (IDAEA-CSIC, PSI, Univ. Bern, Univ. British Columbia, Lawrence Berkeley Natl. Lab.). Initial modeling results using the CrunchFlow code and focusing on Cs+ behavior are reported here.

Download Full-text