The main mechanisms and conditions of interaction of lava-like fuel-containing materials (LFCM) with the atmosphere, water and aqueous solutions are presented. The mechanisms of destruction of the LFCM surface, including ion-exchange processes, hydrolysis, dissolution, oxidation, etc., were analyzed. Inhomogeneous diffusion coefficients for UO22+, Cs+ ions at the interface “aqueous solution of radioactive elements – LFCM” were calculated. The interdiffusion processes and the rate of penetration into the porous medium of the reaction front of the internal hydrolysis of the silicon-oxygen network during interaction with an aqueous solution were analyzed, where the reaction and adsorption processes are hidden in the rate of internal hydrolysis.