High level waste properties

Devitrification and leaching analyses of four waste glasses were made to compare non-radioactive compositions to compositions made using fully radioactive waste calcine. Microstructural analyses of the phase behavior of glasses were performed by means of optical microscopy, x-ray diffraction, x-ray fluorescence, scanning electron microscopy, and electron microprobe analysis. The author's summary of the major findings are: Melt insoluables and crystallization products were found to the same extent in both radioactive and non-radioactive glasses of similar composition. High radiation field appeared to have no effect on the crystallization behavior. The results of long-term IAEA static leach tests indicated no significant difference between the average leach rates of the fully radioactive and non-radioactive glass formulations. Glass composition was more important in determining leach rates than was the extent of devitrification. In both short time tests at 75/sup 0/C or longer leach tests at 25/sup 0/C elemental analyses suggested that congruent dissolution did not occur