Microstructural changes in irradiated silica based glasses

Radiation Damage of Glasses for Nuclear Waste Storage: Optical and Microstructural Aspects

“…Therefore, the obtained results may be considered as corresponding to extremely high local damage conditions which could be conceived in nuclear waste glasses. The first observations, performed in pure vitreous silica, were rather deceiving, since no defect agglomeration was detected, even with fully focussed beam at each of the adopted irradiation temperatures from RT to about 800 K (11). Such absence of microstructural changes has also been confirmed by other authors (23) and it is an important factor which needs justification in all models of interpretation of those phenomena which conversely take place readily in more complex glasses.…”

“…More recently, we have extended our investigations to explore defect clustering effects with special regard to the nucleation and growth of oxygen gas bubbles in electron irradiated borosilicate glasses (11)(12)(13)(14). In the following, we shall describe some of the most relevant obtained experimental results which will further be discussed within the limits of a first attempt to unify into a single frame of interpretation the different phenomena taking place both at the atomistic and at the microstructural scale.…”

A transmission electron microscopy study of radiation damages to β-dicalcium (Ca2SiO4) and M3-tricalcium (Ca3SiO5) orthosilicates

“…The type of radiation damage and/or some comments relative to the irradiated particle are given in the far right column of the was shown that quartz amorphizes under the electron beam [12,13], and that this transformation can be considered more or less rapid depending on the polymorph, cristobalite transforming faster than tridymite, which transforms faster than quartz [14]. From the microstructural point of view, it has long been known that pure silica remains stable under MeV electron irradiation (typically at 1 MeV) [16,17], and that the presence of cationic impurities migrating under the electron beam in silicate glasses are responsible for the observed formation of oxygen bubbles in these compounds [18]. With decreasing electron energy to 200 keV, and assuming unchanged the energy deposition process, the stability of pure SiO 2 under electron irradiation should not in principle be questioned.…”

Why neutron guides may end up breaking down? Some results on the macroscopic behaviour of alkali-borosilicate glass support plates under neutron irradiation

“…The irradiation induced shrinking of amorphous SiO 2 has been correlated more recently to an increase of the small silicon ring concentration and the associated decrease of the Si-O-Si bond angle [30,31]. In contrast, further studies using a variety of radiation sources [12,32,33,14,13,34] show less marked effects on vitreous silica when irradiated with electrons and photons than those found for vitreous borosilicate. For this kind of glass, the macroscopic evolution under irradiation has also been correlated to structural changes [35].…”