The behaviour of waste glass was investigated under open site disposal conditions. This glass was produced by vitrification of intermediate level radioactive waste from nuclear power plants. Two types of borosilicate glasses were obtained for two different reactor wastes, WWER and RBM.K. Leaching and alteration mechanisms are discussed as well as the data processing technique used for these long term tests. The decay of radionuclides was accounted for in order to obtain correct results. The leaching factors obtained can be used for the assesment of radionuclide retention. Discontinuous leaching of Cs-137 has been observed during more than 8 years testing time. The fluctuating leaching rate depends on glass composition. The average leaching rate remains within (0.4 – 4) μg/sq. sm·day.Alteration of waste glass includes the formation of surface layers and cracks on the glass surface. SEM analysis of glass was used to show these surface layers. The thickness of the layers was determined to be within 2–6 μm. The structure of these layers depends on glass composition and the interfacing environment.

Alkali-borosilicate glasses are widely used in nuclear industry as a matrix for immobilisation of hazardous radioactive wastes. Durability or corrosion resistance of these glasses is one of key parameters in waste storage and disposal safety. It is influenced by many factors such as composition of glass and surrounding media, temperature, time and so on. As these glasses contain radioactive elements most of their properties including corrosion resistance are also impacted by self-irradiation.The effect of external gamma-irradiation on the short-term (up to 27 days) dissolution of waste borosilicate glasses at moderate temperatures (30¢X to 60¢XC) was studied. The glasses studied were Magnox Waste glass used for immobilisation of HLW in UK, and K-26 glass used in Russia for ILW immobilisation. Glass samples were irradiated under ×-source (Co-60) up to doses 1 and 11 MGy. Normalised rates of elemental release and activation energy of release were measured for Na, Li, Ca, Mg, B, Si and Mo before and after irradiation. Irradiation up to 1 MGy results in increase of leaching rate of almost all elements from both MW and K-26 with the exception of Na release from MW glass. Further irradiation up to a dose of 11 MGy leads to the decrease of elemental release rates to nearly initial value. Another effect of irradiation is increase of activation energies of elemental release.

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