PNNL

Abstract

This article summarizes recent studies of electron irradiation damage in sodium borosilicate, iron phosphate and aluminophosphate glass waste forms using a modern analytical electron microscope. Three different borosilicate and iron phosphate glasses and an aluminophosphate glass were studied. Results indicate that all these glasses decomposed under the 200 kV electron irradiation. Migration of alkali elements from the irradiated centers to the peripheries under irradiation occurred in the alkali-element containing glasses, which results in the formation of alkali-depleted and -enriched phases. Formation of bubbles was only observed in the alkali-element containing iron phosphate and aluminophosphate glasses, not in the sodium borosilicate glasses when irradiated over a broad of dose rates. Separation of boron-rich phase from silicon-rich phase, iron-rich/aluminum-rich phase from phosphorous-rich domains were observed in the three types of glasses, respectively. Further irradiation resulted in formation of small particles. In the Fe-containing borosilicate glasses, the Fe is associated with the boron-rich phases after phase separation.