Effect of rare earth components on product consistency test (PCT) boron release

Borosilicate glass meets these three conditions to a high degree. Out of various tests that have been developed to assess the chemical durability of nuclear waste glass, the product consistency test (PCT) has been selected as an acceptability gauge for the geological repository. A property-composition database, complied from more than 50 studies, contains around 3406 nuclear waste glass compositions of which over 1600 possess valid PCT boron release data. The effect of rare earth oxides on the PCT boron release was estimated by fitting Eq. (2) to 1627 data. The result indicate that Gd₂0₃, Ld₂O₃ and Nd₂O₃ tend to decrease chemical durability of borosilicate glasses (i.e., increase the normalize release of boron), whereas Ce₂O₃ has a beneficial effect.