It is necessary to evaluate the influence of the colloid on radionuclide migration under geological disposal environment for safety assessment of radioactive waste disposal. In this study, batch sorption experiments and column transport experiments were carried out to evaluate the availability of analytical model of radionuclide migration based on assumption of equilibrated sorption among radionuclide, colloid and rock. Granodiorite was used in the experiments. Bentonite colloid sorbed by strontium was injected into the parallel plate made by the granodiorite.
The comparison between the experimental and the calculated results of the column experiments showed the good agreements by using constant sorption ratio of tracer among the colloid, rock, and aqueous phase. This result indicates the availability of the model for the safety assessment. The flow rate of the column experiments was rather high compared with the natural groundwater flow rate, therefore the kinetic approach is still important to assess the colloidal transport and its effect on the radionuclide migration in the natural groundwater flow.
