Retention of Cs in Boom Clay: comparison of data from batch sorption tests and diffusion experiments on intact clay cores

TY - JOUR

T1 - Retention of Cs in Boom Clay: comparison of data from batch sorption tests and diffusion experiments on intact clay cores

AU - Maes, Norbert

AU - Salah, Sonia

AU - Jacques, Diederik

AU - Aertsens, Marc

AU - Van Gompel, Marc

AU - De Cannière, Pierre

AU - Velitchkova, N.

N1 - Score = 10

PY - 2008/11

Y1 - 2008/11

N2 - For performance assessment analysis of a high-level waste and spent fuel disposal in a geological formation, retention data are needed. In most cases, retention data are derived from batch sorption experiments on dispersed systems but the applicability of these data for the real compacted state is still a point of debate. Cesium retention onto Boom Clay was measured by batch sorption tests on dispersed systems and by diffusion experiments on intact clay cores and the sorption parameters obtained from both methods were compared. In a dispersed system, the concentration dependent uptake of cesium onto Boom Clay is described using the generalised 3-sites cation-exchange model for illite developed by Bradbury and Baeyens. In the compacted state, diffusion experiments resulted in reproducible and robust values for the apparent diffusion coefficient. The determination of retardation factors suffered from a large uncertainty making a good comparison troublesome. A chemical coupled transport simulation for the Cs migration in Boom Clay based on the ion exchange model suggests that only part of the sorption sites are accessible in the compact clay. As illustrated for Cs retention in Boom Clay, conversion of batch sorption data to compacted systems can not be applied in a straightforward way.

AB - For performance assessment analysis of a high-level waste and spent fuel disposal in a geological formation, retention data are needed. In most cases, retention data are derived from batch sorption experiments on dispersed systems but the applicability of these data for the real compacted state is still a point of debate. Cesium retention onto Boom Clay was measured by batch sorption tests on dispersed systems and by diffusion experiments on intact clay cores and the sorption parameters obtained from both methods were compared. In a dispersed system, the concentration dependent uptake of cesium onto Boom Clay is described using the generalised 3-sites cation-exchange model for illite developed by Bradbury and Baeyens. In the compacted state, diffusion experiments resulted in reproducible and robust values for the apparent diffusion coefficient. The determination of retardation factors suffered from a large uncertainty making a good comparison troublesome. A chemical coupled transport simulation for the Cs migration in Boom Clay based on the ion exchange model suggests that only part of the sorption sites are accessible in the compact clay. As illustrated for Cs retention in Boom Clay, conversion of batch sorption data to compacted systems can not be applied in a straightforward way.

KW - Retention

KW - diffusion

KW - sorption

KW - clay

KW - cesium

KW - Boom Clay

UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/ezp_92644

UR - http://knowledgecentre.sckcen.be/so2/bibref/5316

U2 - 10.1016/j.pce.2008.10.002

DO - 10.1016/j.pce.2008.10.002

M3 - Article

VL - 33

SP - S149-S155

JO - Physics and Chemistry of the Earth

JF - Physics and Chemistry of the Earth

SN - 1474-7065

IS - Supplement 1

T2 - Clays in natural and engineered barriers for radioactive waste confinement

Y2 - 17 September 2007 through 20 September 2007

ER -