Abstract: THE STUDY ON RADIONUCLIDE MIGRATION IN GEOLOGIC MEDIAWANG RONGSHU；FENG WEI （Department of Chemical Engineering，Tianjin Universljy，300072）ABSTRACT The only reasonable mechanism by which radionuclide can be brought from a repository tobiosphere is through migration in barrier materials under the movement of groundwater． Throughgreat amount of experiments，it has been proved that the diffusion of radionuclides in geologic me-dia obeys Ficy's econd Law. This paper gives the analytic solution of the radionuclide migration e-quation by the Laplace transformation. Thus we can predict the migration of radionuclides in cer-tain medium conveniently. Key words Nuclide migration Diffusion Groundwater