X-ray CT imaging of vitrified glasses containing simulant radioactive wastes: structure and chemical reactions of glass beads and wastes in the cold cap

摘要

Simulated cold caps for a liquid fed ceramic melter (LFCM) were prepared using a special electric furnace that incorporated a temperature gradient and a synchronously movable stage that fed glass beads and simulant nuclear waste (NW) solution. X-ray computed tomography (X-ray CT) analysis was used for nondestructive investigation of the simulated cold cap structure after rapid quenching. Traces of the melting of the supplied glass beads, reactions with NW components, the production of gas phases and their encapsulation as bubbles/voids, together with homogenization, were clearly seen in the 3-dimensional image data. Changes in the concentration of NW in solution greatly affected the size and spatial distribution of bubbles/voids in the quenched simulated cold cap. The first application of the X-ray CT technique was found to have high potential to reveal the thermal properties of the cold cap in LFCM system.