DIFFUSION OF RADON IN POROUS-MEDIA SATURATED WITH GELS AND EMULSIONS

The effective diffusion coefficient of radon was determined in polymer /silicate gels and clay suspension used as sealing materials in enviro nmental protection. On the basis of the experimental findings, it was concluded that both materials drastically decrease the convective mass transport in porous media. Simultaneously, the effective diffusion co efficient was reduced significantly. Thus, the radon flux might be dec reased by 5 to 6 orders of magnitude in porous systems originally havi ng gas or low water saturation by injection of gel-forming materials o r placement of clay suspensions. At high water saturation, however, th e diffusion transport of radon can be slightly restricted in consolida ted and unconsolidated porous media. The laboratory studies may firmly allow us to conclude that hydrogels and clay suspensions are prospect ive candidates in an integrated environmental technology to be used fo r restriction of radon migration in subsurface regions.