Abstract
Document available in extended abstract form only. In France, low and medium level radioactive waste of short period (nuclides with a half-life less than 31 years and an activity ranging from 100 to 1,000,000 Bq/g) is stored in concrete constructions on a surface site in Soulaines-Dhuys (Aube). The site was chosen for its simple geology: it entirely lays on an aquifer formation, the Upper Aptian sands, above a Lower Aptian impermeable clay formation. The site is surrounded by the Noues d'Amance stream, which serves as the single outlet of the groundwater on the site. The objective of this study is to improve knowledge of radionuclides migration in the aquifer formation to improve safety, using U(VI) as an example and focusing on colloids, capable of transporting U(VI) on long distances. The sediment is composed of two main phases: quartz and clay minerals (glauconite, with a small fraction of kaolinite and smectite), with relative amounts of 91 and 6% in weight, respectively. The aquifer water contains clay colloids, invisible to the eye though observed with SEM and TEM in a non disturbed sample. No signal was measured with usual light diffusion techniques and Asymmetric Flow Field-Flow Fractionation (AF4). Only the Laser Induced
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Le Cointe, P.;
[1]
Centre de Geosciences, Ecole des Mines de Paris, 35 rue St-Honore, 77305 Fontainebleau Cedex (France);
ANDRA 1/7 rue Jean Monnet - 92298 Chatenay Malabry Cedex (France)];
Grambow, B.;
Piscitelli, A.;
Montavon, G.;
[1]
Van der Lee, J.;
[2]
Giffaut, E.;
Schneider, V.
[3]
- Laboratoire SUBATECH, UMR 6457 Ecole des Mines/CNRS/Universite, 4 rue A. Kastler, BP 20722, 44307 Nantes Cedex 03 (France)
- EDF R ete D, Site des Renardieres, Route de Sens - Ecuelles, 77250 Moret sur Loing (France)
- ANDRA 1/7 rue Jean Monnet - 92298 Chatenay Malabry Cedex (France)
Citation Formats
Le Cointe, P., Centre de Geosciences, Ecole des Mines de Paris, 35 rue St-Honore, 77305 Fontainebleau Cedex (France), ANDRA 1/7 rue Jean Monnet - 92298 Chatenay Malabry Cedex (France)], Grambow, B., Piscitelli, A., Montavon, G., Van der Lee, J., Giffaut, E., and Schneider, V.
Migration of uranium in the presence of clay colloids in a sandy aquifer.
France: N. p.,
2010.
Web.
Le Cointe, P., Centre de Geosciences, Ecole des Mines de Paris, 35 rue St-Honore, 77305 Fontainebleau Cedex (France), ANDRA 1/7 rue Jean Monnet - 92298 Chatenay Malabry Cedex (France)], Grambow, B., Piscitelli, A., Montavon, G., Van der Lee, J., Giffaut, E., & Schneider, V.
Migration of uranium in the presence of clay colloids in a sandy aquifer.
France.
Le Cointe, P., Centre de Geosciences, Ecole des Mines de Paris, 35 rue St-Honore, 77305 Fontainebleau Cedex (France), ANDRA 1/7 rue Jean Monnet - 92298 Chatenay Malabry Cedex (France)], Grambow, B., Piscitelli, A., Montavon, G., Van der Lee, J., Giffaut, E., and Schneider, V.
2010.
"Migration of uranium in the presence of clay colloids in a sandy aquifer."
France.
@misc{etde_22430197,
title = {Migration of uranium in the presence of clay colloids in a sandy aquifer}
author = {Le Cointe, P., Centre de Geosciences, Ecole des Mines de Paris, 35 rue St-Honore, 77305 Fontainebleau Cedex (France), ANDRA 1/7 rue Jean Monnet - 92298 Chatenay Malabry Cedex (France)], Grambow, B., Piscitelli, A., Montavon, G., Van der Lee, J., Giffaut, E., and Schneider, V.}
abstractNote = {Document available in extended abstract form only. In France, low and medium level radioactive waste of short period (nuclides with a half-life less than 31 years and an activity ranging from 100 to 1,000,000 Bq/g) is stored in concrete constructions on a surface site in Soulaines-Dhuys (Aube). The site was chosen for its simple geology: it entirely lays on an aquifer formation, the Upper Aptian sands, above a Lower Aptian impermeable clay formation. The site is surrounded by the Noues d'Amance stream, which serves as the single outlet of the groundwater on the site. The objective of this study is to improve knowledge of radionuclides migration in the aquifer formation to improve safety, using U(VI) as an example and focusing on colloids, capable of transporting U(VI) on long distances. The sediment is composed of two main phases: quartz and clay minerals (glauconite, with a small fraction of kaolinite and smectite), with relative amounts of 91 and 6% in weight, respectively. The aquifer water contains clay colloids, invisible to the eye though observed with SEM and TEM in a non disturbed sample. No signal was measured with usual light diffusion techniques and Asymmetric Flow Field-Flow Fractionation (AF4). Only the Laser Induced Breakdown Detection (LIBD) technique could characterize the size (between 30 and 70 nm) and the concentration (around 10 ppb) of the clay colloids. Batch experiments were carried out to define U(VI)-Quartz and U(VI)-Clay interactions, with U(VI) concentration, pH and pCO{sub 2} being the studied variables. The data were modelled with the Chess geochemistry code developed at the Paris School of Mines and compared to literature. Davis applied model for U(VI)-Quartz interaction and Bradbury and Baeyens applied model for U(VI)-Illite interaction adequately describe the experimental data. To know if clay colloids can move freely in the groundwater, pore size was measured using X-ray microtomography. Nanoparticles tracing was done with polystyrene standards on different sediment samples (core sample, reconsolidated auger sample and clay-free reconsolidated auger sample). The filtration threshold has been defined between 70 and 100 nm, except for the clay-free sample, for which it is above 500 nm. Laboratory column experiments were performed with 70 nm clay colloids, U(VI) and clay colloids + U(VI). To make the system simpler, the clay fraction was removed from the sediment and the experiments were carried out at a low ionic strength, to avoid clay colloids flocculation. The breakthrough behaviour of clay colloids and U(VI) was monitored and compared to conservative tracers (HTO and {sup 36}Cl). The data were modelled with the HYTEC reactive transport code developed at the Paris School of Mines, considering both hydrodynamic properties of the porous system (porosity of 30%, Darcy velocity fixed to 3.10{sup -6} m/s, close to the one measured in situ) and the parameters quantifying U(VI)-Quartz and U(VI)-Clay interactions. An in situ tracing experiment was also conducted with both conservative (D{sub 2}O, H{sub 2}{sup 18}O) and colloidal (polystyrene nanoparticles) tracers. The objective is to ensure the reactive transport model, based on laboratory experiments, can be extended to a parcel of the site, and finally to the whole site, using experimental and modelling data collected by Andra. (authors)}
place = {France}
year = {2010}
month = {Jul}
}
title = {Migration of uranium in the presence of clay colloids in a sandy aquifer}
author = {Le Cointe, P., Centre de Geosciences, Ecole des Mines de Paris, 35 rue St-Honore, 77305 Fontainebleau Cedex (France), ANDRA 1/7 rue Jean Monnet - 92298 Chatenay Malabry Cedex (France)], Grambow, B., Piscitelli, A., Montavon, G., Van der Lee, J., Giffaut, E., and Schneider, V.}
abstractNote = {Document available in extended abstract form only. In France, low and medium level radioactive waste of short period (nuclides with a half-life less than 31 years and an activity ranging from 100 to 1,000,000 Bq/g) is stored in concrete constructions on a surface site in Soulaines-Dhuys (Aube). The site was chosen for its simple geology: it entirely lays on an aquifer formation, the Upper Aptian sands, above a Lower Aptian impermeable clay formation. The site is surrounded by the Noues d'Amance stream, which serves as the single outlet of the groundwater on the site. The objective of this study is to improve knowledge of radionuclides migration in the aquifer formation to improve safety, using U(VI) as an example and focusing on colloids, capable of transporting U(VI) on long distances. The sediment is composed of two main phases: quartz and clay minerals (glauconite, with a small fraction of kaolinite and smectite), with relative amounts of 91 and 6% in weight, respectively. The aquifer water contains clay colloids, invisible to the eye though observed with SEM and TEM in a non disturbed sample. No signal was measured with usual light diffusion techniques and Asymmetric Flow Field-Flow Fractionation (AF4). Only the Laser Induced Breakdown Detection (LIBD) technique could characterize the size (between 30 and 70 nm) and the concentration (around 10 ppb) of the clay colloids. Batch experiments were carried out to define U(VI)-Quartz and U(VI)-Clay interactions, with U(VI) concentration, pH and pCO{sub 2} being the studied variables. The data were modelled with the Chess geochemistry code developed at the Paris School of Mines and compared to literature. Davis applied model for U(VI)-Quartz interaction and Bradbury and Baeyens applied model for U(VI)-Illite interaction adequately describe the experimental data. To know if clay colloids can move freely in the groundwater, pore size was measured using X-ray microtomography. Nanoparticles tracing was done with polystyrene standards on different sediment samples (core sample, reconsolidated auger sample and clay-free reconsolidated auger sample). The filtration threshold has been defined between 70 and 100 nm, except for the clay-free sample, for which it is above 500 nm. Laboratory column experiments were performed with 70 nm clay colloids, U(VI) and clay colloids + U(VI). To make the system simpler, the clay fraction was removed from the sediment and the experiments were carried out at a low ionic strength, to avoid clay colloids flocculation. The breakthrough behaviour of clay colloids and U(VI) was monitored and compared to conservative tracers (HTO and {sup 36}Cl). The data were modelled with the HYTEC reactive transport code developed at the Paris School of Mines, considering both hydrodynamic properties of the porous system (porosity of 30%, Darcy velocity fixed to 3.10{sup -6} m/s, close to the one measured in situ) and the parameters quantifying U(VI)-Quartz and U(VI)-Clay interactions. An in situ tracing experiment was also conducted with both conservative (D{sub 2}O, H{sub 2}{sup 18}O) and colloidal (polystyrene nanoparticles) tracers. The objective is to ensure the reactive transport model, based on laboratory experiments, can be extended to a parcel of the site, and finally to the whole site, using experimental and modelling data collected by Andra. (authors)}
place = {France}
year = {2010}
month = {Jul}
}