PNNL

Abstract

During batch-to-glass conversion, the glass-forming melt connects, creating a foam layer between the batch and glass melt. Due to its transient nature and opacity, the investigation of this foam layer presents a formidable challenge. In this work, we use in-situ X-ray computed tomography to characterize the foam morphology that evolves during batch-to-glass conversion of a simulated nuclear waste glass. Rapid one-minute scans with voxel size of 38 micrometers were performed to capture the foam structure during heating. Geometric volume, total porosity, and bubble size distribution are reported. Using evolved gas analysis and considering the temperature-dependent melt viscosity in combination with X-ray data, we explain the evolution of foam structure during the foam growth and subsequent collapse.