Chemical and physical modifications in waste glasses ion-implanted at different temperatures
The French nuclear borosilicate waste glass R7T7 was implanted with Kr-ions of 100 to 380 keV energy at different temperatures up to 350 C, thus covering and extending the range of temperatures expected in a repository for vitrified radioactive high level waste. The ion dose was kept constant at 1.0 E15 ions/cm2. Following implantation, and with unimplanted glasses for comparison, hardness and fracture toughness K(Ic) were determined with Vickers identations, and leaching was done in deionised water at 100 and 150 C. The leached glasses were analysed by RBS and ERDA. A significant increase in K(Ic) was observed for glasses implanted at room temperature. This positive effect diminished with increased implantation temperatures, indicating that damage-induced stresses are decreased at higher implantation temperature. Leaching produced hydration and the well known surface enrichment of elements of low solubility (Ti, rare earths etc.). In contrast to the behaviour of K(Ic), damage-induced enhanced leaching and hydration were also observed at the higher implantation temperatures. The damage features (including enhanced Na-migration) causing increased leaching recovered at much higher temperatures than those responsible for increased fracture toughness. The results are compared with similar data obtained for the German waste glass GP 98/12, and with glasses damaged by alpha-decay of incorporated short-lived 244Cm.
Bibliographic Reference: Paper presented: E-MRS Symposium on Chemical and Physical Modifications Induced by Irradiation in Glasses, Strasbourg (FR), Nov. 4-8, 1991
Availability: Available from (1) as Paper EN 36567 ORA
Record Number: 199210195 / Last updated on: 1994-12-02
Original language: en
Available languages: en