Effect of thermal annealing on the properties of boron-containing basalt systems containing radioactive waste components

The effect of thermal annealing on the resistance of borosilicate systems to crystallization and on the hydrolytic resistance of the materials was examined. The systems containing individual components of radioactive wastes of both REE + TUE and, for comparison, Cs + Sr fractions were examined. Under the experimental conditions (annealing temperature 800°C, time 100 h), the materials of all the examined compositions crystallize to certain extent. The matrices incorporating REE crystallize to the least extent. In all the cases, the crystalline phase contains mainly compounds of the component being incorporated and also Fe compounds. A distinctive feature of the matrices containing lanthanide oxide and of the boron-containing basalt matrix itself is increased resistance to leaching in water after annealing in the temperature range 400–500°C.