DIFFUSION OF RADON IN GELS AND CLAY BARRI ERS APPLIED IN ENVIRONMENTAL-PROTECTION

The effective diffusion coefficient of radon was determined in polymer /silicate gels and Montax/clay suspension used as sealing materials in environmental protection. On the basis of the experimental finding it was concluded that both materials drastically decrease the convective mass transport in porous media. Simultaneously, the effective diffusi on coefficient was reduced significantly. Thus, the radon flux might b e decreased by 5-6 orders of magnitude in porous systems having low wa ter saturation by injection of gel-forming materials or placement of c lay suspensions. At high water saturation, however, the diffusion tran sport of radon can only be slightly restricted in consolidated and unc onsolidated porous media. Laboratory studies permit the conclusion tha t hydrogels and clay suspensions are prospective candidates in an inte grated environmental technology to be used for restriction of radon mi gration in subsurface regions.