Investigation of the thermal behaviour of high level waste glass in steel canisters during cooling and at equilibrium

Since the decision was taken to vitrify high-level-liquid waste from reprocessing operations worldwide, the further behaviour of produced glass blocks became interesting especially during cooling. Crack formation and its influence of surface increase, heat removal, equilibrium temperature distribution were investigated with inactive simulates and finally with two high-level glass canisters. In both cases the acoustic emission analysis was used simultaneously with temperature profile recording to evaluat e different cooling modes on the above mentioned characteristics. As result one can state, that crack free active blocks cannot be produced due to remaining thermal gradients. However heat removal is not hampered by the cracks formed. The equilibrium temerature profils can be calculated after fitting the computer codes with results of this report and surface increase estimates are evaluated according to different cooling procedures.