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Kurosawa, Susumi; Ibaraki, Motomu*; Scott, J.*; Yui, Mikazu; Russell, A.*
JNC TN8400 2004-016, 35 Pages, 2004/09
JNC-TN8400-2004-016.pdf:1.18MB
To evaluate the influence of colloids on radionuclide transport through the fractured rock, the colloid and radionuclide retardation experiment project were carried out in a shear zone in the Grimsel Test Site on one of JNC-NAGRA internatinal collaboration programs. In this study, the results of the transport experiments were analyzed by numerical simulation code of radionuclide transport, COLFRAC, which describe colloid-facilitated solute transport in fractured media.
Kurosawa, Susumi; Ibaraki, Motomu*; Yui, Mikazu; Ueta, Shinzo*; Yoshikawa, Hideki
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(3), p.249 - 256, 2004/09
Colloidal effect is one of the major factors to enhance the transport of radionuclide in groundwater. In this study, the impact of kinetic reactions of radionuclide sorption onto both the fracture wall and colloid on the transport behavior of radionuclide were investigated by carrying out the transport experiment of the radionuclide with colloid through fractured rock. In the experiments, the Cs and clay colloid were used as moderately sorbing radionuclide and typical natural colloid by the concentration of 1.0
10
g/l (7.510
mol/l) and 3.510
g/l, respectively. The granodiorite with artificially the single fracture (dimension: 50500.5 mm) was used. The results of the transport experiments were analyzed by numerical simulation code of radionuclide transport COLFRAC which can model radionuclide transport based on either equilibrium or kinetic reaction of radionuclide sorption onto fracture wall and colloid. Consequently, it was indicated that calculated results strongly dep
Kurosawa, Susumi; Yui, Mikazu; Yoshikawa, Hideki; Ibaraki, Motomu*; Ueta, Shinzo*
Abstracts P.510-511, p.510 - 511, 2004/00
Many studies have shown that colloidal particles which exist in ground water can facilitate radionuclide transport in subsurface environments. We conducted a series of laboratory experiments to investigate the effects of radionuclide sorption onto colloids and the surfaces of rock fractures. We focused on overall effects related to the kinetic behavior of those sorption processes. A mixed solution of cesium and clay colloids was injected into an artificially-created single fracture in a granite column. The fracture aperture and length are 0.5 mm and 50 cm, respectively. Numerical simulations were conducted to analyze the experiment results using a numerical code COLFRAC which can simulate colloid-facilitated solute transport in discretely-fractured porous media. The numerical formulation allows for either equilibrium or kinetic sorption onto the fracture walls, and the mobile and filtered colloidal particles. A series of experimental and numerical analyses shows that migration of cesium is facilitated by mobile colloidal particles which can sorb cesium and migrate in the fracture. The analyses also demonstrate that cesium migration is significantly enhanced if desorption of cesium from the colloids is a slow kinetic process and illustrate the importance of evaluating the parameters which describe such kinetic processes. Furthermore, radionuclide transport is likely to be retarded if mobile colloidal particles which sorb radionuclides are vigorously filtered on the fracture surfaces.
Kurosawa, Susumi; Ibaraki, Motomu*; Yui, Mikazu; Ueta, Shinzo*; Yoshikawa, Hideki
Materials Research Society Symposium Proceedings, Vol.824, 473 Pages, 2004/00
We conducted a series of laboratory experiments to investigate the effects of radionuclide sorption onto colloids and the surfaces of rock fractures. We focused on overall effects related to the kinetic behavior of those sorption processes. A mixed solution of cesium and clay colloids was injected into an artificially-created single fracture in a granite column. Numerical simulations were conducted to analyze the experiment results using a numerical code COLFRAC which can simulate colloid-facilitated solute transport in discretely-fractured porous media. A series of experimental and numerical analyses show that migration of cesium is facilitated by mobile colloidal particles which can sorb cesium and migrate in the fracture. The analyses also demonstrate that cesium migration is significantly enhanced if desorption of cesium from the colloids is a slow kinetic process and illustrate the importance of evaluating the parameters which describe such kinetic processes. Furthermore, radionuclide transport is likely to be retarded if mobile colloidal particles which sorb radionuclides are vigorously filtered on the fracture surfaces.
