Investigation of alkali borosilicate glass durability using tritium tracing, β-autoradiography, scanning electron microscopy and ion beam analysis

Abstract A Li–Na-containing borosilicate glass was submitted to aqueous corrosion in static mode in tritiated solutions of various pH at room temperature and 90 °C. Tritium counting, β-autoradiography, scanning electron microscopy (SEM) and ion beam analysis (IBA) techniques have been used to investigate the composition variations of the leached glass surfaces. In an acidic medium, the glass surface is covered by a thick hydrated silica layer; mobile elements like Li, Na and B and transition elements like Fe and Mo are strongly depleted. Near pH 7, relative enrichments of aluminium and iron are shown together with strong Li, Na and B depletions. In a basic medium, the glass surface exhibits iron and molybdenum enrichments whereas mobile elements seem to be kept at their nominal concentration level at the glass surface. The tritium activity and distribution on the leached glass surface is shown to depend strongly on the pH of the tritiated solutions. These observations are correlated with the observed changes of the surface morphology and chemistry characterized by IBA and SEM analysis. Elemental solubility versus pH of various chemical species have been calculated for comparison purpose with the experimental observations.