Radiation damage in silica-based glasses: Point defects, microstructural changes and possible implications on etching and leaching

Quantification of the boron speciation in alkali borosilicate glasses by electron energy loss spectroscopy

“…As insulators most glasses are not conductive in scanning electron microscope (SEM) and/or TEM instruments and thus, severe charging or heating effects can occur during the experiments, which may cause errors in the microstructural characterization. Previous studies have shown that the electron-beam irradiation damage could result in oxygen bubble formation, crystallization or phase separation in glasses 12 13 14 . In alkali borosilicate (ABS) glasses, one of the irradiation effects is the transformation of tetrahedral BO 4 into planar BO 3 units as a result of the removal of alkali species out of the illuminated area, and the speed of this transformation decreases with the size of the alkali ions increase (Li + , Na + , K + and Cs + ) 11 .…”

Effects of radionuclide decay on waste glass behavior: A critical review

“…Manara et al [104] noted ~50% volume expansion swelling after an electron fluence of -7 x 1020 e-/cm 2 . At this stage, the damage effects were saturated and no further increases in volume were noted for fluences of up to ~9 x 1020 e-/cm 2 , even though the bubble density still continued to increase (Fig.…”

“…The formation of these bubbles has the potential to increase the available surface area of the glass and may, therefore, affect leach rates [104]. Inagaki et al [65] examined annealing effects on helium bubbles that formed as a result of alpha decay processes.…”

“…Continued ionization of the glass in the absence of Na+ will lead to the formation of Si-O-Si bonds, 02, and electrons, with the 02 gas accumulating as bubbles within the glass. Bubble formation and gas evolution depend on the glass composition, with high-silica glasses displaying the lowest outgassing rates, while the addition of other oxides increased the oxygen evolution rate Manara et al [95,104] observed a marked increase in the electron flux required to induce bubble formation concurrent with increasing irradiation temperature between ~50 and 300*C. DeNatale and Howitt [98] examined the effect of cumulative dose vs. temperature in inducing bubble formation over a range of temperatures from ambient to 450*C. These authors observed a minimum in the total dose required to form bubbles located at approximately 250*C, with an increase in the threshold dose at both higher and lower temperatures (Fig. 10).…”

“…The increasing ease at which bubbles occur when temperatures are increased to 250*C has been used to support a diffusion behavior model for the formation of bubble-or void-like defects, although the increasing dose required to induce bubble formation between 250 and 450*C is not readily explained by a diffusion model. Manara et al [104] examined the complex interdependence of both temperature and glass composition on oxygen bubble formation in sodium silicate glasses. In these tests, the largest swelling rates were detected for glasses with lower silica concentrations (Fig.…”