Waste Glass Leaching and Alteration Under Conditions of Open Site Tests

Abstract

ABSTRACTThe 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.