Characterization of high cesium containing glass-bonded ceramic waste forms

High cesium containing glass-bonded ceramic waste form samples were prepared and characterized to identify possible cesium phases present in glass-bonded ceramic waste forms developed for the containment of fission product bearing salts. Major phases of the waste forms are sodalite and glass. A combination of powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and nuclear magnetic resonance spectroscopy (NMR) were used to study the multiphase nature of these waste forms. Cesium was found to be present in the higher loaded waste forms in a cesium aluminosilicate phase with an analcime structure and a 1:1 Si:Al ratio, a pollucite phase, and also in the glass phase. The glass phase contains the majority of the cesium at lower loadings, however some pollucite also remains. Cesium was not detected in the sodalite phase of any of the samples.