A compilation and evaluation of radionuclide diffusion and sorption properties in the buffer material for the high-level waste repository

In this study, the radionuclide diffusion and sorption properties of the compacted bentonite were collected from the literatures. They show a similar trend although the spread in the data due to the difference in the type of bentonite and the measuring techniques exists. The radionuclide diffusion coefficients of bentonite are found to decrease with the increasing dry density of the bentonite. The radionuclide diffusion coefficient can be expressed as a second order polynomial of the dry density of bentonite. The distribution of diffusion coefficients is fitted by log-normal distribution at the 0.05 significance level. The distribution of radionuclide equilibrium distribution coefficient can also be approximated by log-normal distribution. For sorbing radionuclides, the radionuclide diffusion coefficients calculated using equilibrium distribution coefficients are much lower than measured ones