Abstract : This report deals with the HYTEC model, coupling chemical and hydrodynamic processes, and its application to the recycling of inorganic wastes and the disposal of hazardous and radioactive wastes. A common feature is the assessment of geomaterial durability while submitted to chemical disturbances by their industrial or natural environment and, reciprocally, the quantification of contaminant fate in soils and aquifers. Research papers In a first section numerically oriented, HYTEC is validated by means of an intercomparison exercise based on oxidative UO2 dissolution and the subsequent migration of U species in subsurface environments. A numerical approach of leaching tests is also discussed. Several researches based on HYTEC follows. The evolution of the cement/clay interface is simulated in the framework of the multi-barrier system of radioactive waste disposal and the Tournemire engineering analog ; discriminating between the physical and chemical key processes. The physico-chemical processes of cement biodegradation by fungi are investigated with a focus on acidic hydrolysis and complexation by biogenic carboxylic acids. Modeling of source-terms and ageing with respect to contaminant migration is discussed in the case of the chemical alteration of spent fuel pellets under disposal conditions by considering radiolytic dissolution, inhibiting effect and radioactive decay, and by analyzing the effect of fractures on the containment properties of subsurface disposal facilities of stabilized/solidified waste. Leaching lab experiments applied to steel slag and the chemical evolution of leachate from MSWI subbases of two pilot roads over 10 years are eventually modelled to better estimate the environmental impact of such recycling scenarios. On-going research In the straight lines of the modeling of radioactive waste disposal, a first perspective is to investigate the transient states driven by thermal gradient and water resaturation of the near-field barriers and their effects on steel/cement/clay interactions. An other perspective is to model the environment control on the dissolution of vitrified waste by using the GRAAL model (CEA) based on the concept of passivating reactive interface. With respect to biodegradation, the effect of several types of biogenic acids on leaching of CEM-I and CEM V cement pastes will be investigated with HYTEC as well as iron/clay interactions catalyzed by sulfate and iron reducing bacteria. HYTEC modeling of the chemical processes occurring in soil stabilization by lime and the treatment durability in civil engineering is also in progress.