Abstract: MIGRATION STUDIES OF FISSION PRODUCT NUCLIDES IN ROCKS Ⅴ.DIFFUSION AND PERMEABILITY OF NUCLIDE~(125)I IN MARBLEWen Ruiyuan;Gao Hongcheng;Wang Xiangyun(Deportment of Technical Physics,Peking University,Beijing 100871)Abstract:The migration behaviour of nuclide~(125)Ⅰ,as a simulation of the longlived fission product~(125)I,in marble is studied in selfdesigned cells.A series of the most important parameters of diffusion and permeability(e.g.,intrinsic diffusion coefficient,dispersion coefficient and interstitial flow velocity,etc.)are determined.Based on the differrential equation of the nuclide migration,the distribution function and numerical solution of~(125)Ⅰin marble are presented.The results show that the migration velocity of~(125)I in marble is fast,indicating that it is not suitable to dispose nuclear waste in marble.Keywords:~(125)I Nuclide migration Nuclear waste disposal Marble