Structural changes on the surfaces of borosilicate glasses induced by gamma‐ray irradiation

Abstract

Vitrification is a kind of glass that can solidify high‐level radioactive waste (HLW). As the basic material of vitrification, borosilicate glass was studied extensively. To keep HLW away from the biosphere, the tolerance of borosilicate glass to irradiation is important. In this work, various samples of borosilicate glass with different compositions were irradiated with gamma rays at ambient temperature to study their stability. The hardness, moduli, and microscopic changes on surfaces of the borosilicate glasses were measured at specific absorbed doses. Upon the gamma irradiation, the structural changes on surfaces of borosilicate glasses were identified, which were strongly influenced by the composition of borosilicate glasses. The results demonstrate that gamma irradiation, as well as beta irradiation, might strongly influence the properties of vitrification. The irradiation effects on vitrification induced by gamma irradiation should be paid more attention to than before.

Elemental behaviors of γ‐irradiated borosilicate glass as a vitrification model

“…The intensity changes at these two locations are similar to a former report, 20 where significant changes of nano hardness and modulus occurred in the samples. The third change is the appearance of a peak at 1640 cm −1 , which is caused by the H‐O‐H bending vibration of free water 29 .…”

“…After cooling again, the borosilicate glasses were cut into sheets with a dimension of 10 ×10 ×1 mm and finally well‐polished. The hardness of NBS9 and NBS10 were both 7.8 GPa, and modulus 87.1 GPa and 86.9 GPa, respectively 20 …”

“…The hardness of NBS9 and NBS10 were both 7.8 GPa, and modulus 87.1 GPa and 86.9 GPa, respectively. 20 Prior to irradiation, the NBS samples were ultrasonically cleaned by acetone, ethanol, and deionized water to remove possible impurities. Then the borosilicate glasses were attached with carbon tape in two polypropylene (PP) boxes for further γ irradiation.…”

“…However, recently Mao presented that both γ irradiation and β irradiation have influence on the mechanical properties of Na-Bi-Si (NBS) glass. 20 The effects are also closely related to the composition of borosilicate glass. Additionally, as one of the complex processes in geological disposals, γ irradiation would have obvious effects on the subsequent behaviors, such as the alteration/corrosion, if the glass is corroded in groundwater over a long time.…”

“…Above researches have proven that the γ‐ray resistance of the borosilicate glass is dependent on the glass compositions, but no obvious effects have been shown. However, recently Mao presented that both γ irradiation and β irradiation have influence on the mechanical properties of Na‐Bi‐Si (NBS) glass 20 . The effects are also closely related to the composition of borosilicate glass.…”