Effects of irradiation on the mechanisms controlling the residual rate of an alumino-borosilicate glass
Résumé
The alteration of a four-oxide alumino-borosilicate glass close to ISG was studied in Si saturation conditions at pH 3, pH 7, and pH 9 using solution and post mortem solid analyses. In particular, the study examined the impact of structural disorder on the glass alteration generated by swift heavy ion irradiation (i.e. Se>>Sn). It is shown that the pre-irradiated glass altered approximately 3 times more than the non-irradiated glass, whatever the pH. This increased alteration can be attributed to two factors: an increased hydrolysis speed of the Si-O-B bonds which control the glass dissolution under these Si saturation conditions, and a less passivating alteration layer. The latter effect suggests that the glass structural disorder is retained by the first gel formed, which means very low Si atom mobility during alteration. However, gel maturation tends to mitigate the detrimental effect of radiation damages. These results will contribute to the development of a predictive residual rate model.