Glass formulation development and testing for the vitrification of Oak Ridge tank waste

Abstract

As part of joint project between the Oak Ridge National Laboratory (ORNL) and the Savannah River Technology Center (SRTC), radioactive waste from four different ORNL tank farms will be immobilized. This work, which is funded by the DOE Office of Science and Technology, is designed to create a direct comparison between grouting and vitrification technologies. SRTC efforts have been focused on developing and testing glass formulations for the vitrification of the tank wastes. The radioactive waste is from four different ORNL tank farms: Melton Valley Storage Tanks (MVST), Bethel Valley Evaporator Service Tanks (BVEST), Gunite and Associated Tanks (GAAT), and Old Hydrafracture Tanks (OHF). The sludges in these tanks contain transuranic radionuclides at levels which will make the final waste form (at reasonable waste loadings) TRU. Glass is an acceptable waste form because of its ability to accept a wide variety of components into its network structure. This is important since the waste varies significantly from tank to tank and from tank farm to tank farm. Therefore, glass formulation efforts have centered on developing a formulation that is robust enough to handle large fluctuations in waste composition. Crucible studies have been performed with simulated GAAT, MVST and BVEST sludges. The results of these tests indicate that high waste loadings can be obtained in the glass to significantly reduce the waste volume. This paper will present the results of the glass formulation efforts