摘要
Distribution coefficients (K (d)), apparent diffusion coefficients (D (a)) and retardation factor (Rf) in this work obtained by batch and through-diffusion experiments have been performed, respectively. The accumulative concentration method developed by Crank (The mathematics of diffusion, 12) was applied to realize apparent and effective diffusion coefficient (D (a) and D (e)) of Se. Besides, a non-reactive radionuclide, HTO, was initially conducted in through-diffusion experiment for assessing the ability of radionuclide retardation. The distribution coefficients (K (d)) obtained by batch tests in 14 days under aerobic and anaerobic systems were 6.98 +/- A 0.35 and 5.21 +/- A 0.25 mL/g. Moreover, Rf(cal) and K (d) (cal) of Se obtained from accumulative concentration's method in through-diffusion test showed an obvious discrepancy with the increase of length/diameter (L/D) ratio. However, it presented an agreement of Rf(H/Se) and K (d) (H/Se) in a various L/D ratio by comparison of apparent diffusion coefficient's (D (a)) between HTO and Se. It appears that the Rf(H/Se) and K (d) (H/Se) obtained from the through-diffusion experiments are lower than those derived from the batch experiments. Therefore, it demonstrates that reliable Rf and K (d) of Se by through-diffusion experiments could be achieved at a non-reactive radiotracer (HTO) prior to tests and will be more confident in long-term performance assessment of disposal repository.