Enhanced Hlw Glass Formulations for the Waste Treatment & Immobilization Plant

Current estimates and glass formulation efforts are conservative vis-à-vis achievable waste loadings. These formulations have been specified to ensure that glasses are homogenous, contain essentially no crystalline phases, are processable in jouleheated, ceramic-lined melters and meet WTP Contract terms. The WTP’s overall mission will require the immobilization of tank waste compositions that are dominated by mixtures of aluminum, chromium, bismuth, iron, phosphorous, zirconium, and sulfur compounds as waste-limiting components. Glass compositions for these waste mixtures have been developed based upon previous experience and current glass property models. DOE has a testing program to develop and characterize HLW glasses with higher waste loadings. This work has demonstrated the feasibility of increases in waste loading from 25 wt% to 33-50 wt% (based on oxide loading) in the glass depending on the waste stream. It is expected these higher waste loading glasses will reduce the HLW canister production requirement by 25% or more. NOMENCLATURE DOE US Department of Energy DM-10 DuraMelter-10 (0.02 m 2 melt surface area) DM-100 DuraMelter-100 (0.11 m 2 melt surface area) DM-1200 DuraMelter-1200 (1.2 m 2 melt surface area) WTP HLW Melter 3.75 m 2 melt surface area ILAW Immobilized Low-Activity Waste IHLW Immobilized High-Level Waste MT Metric Tonnes ORP Office of River Protection PCT Product Consistency Test (ASTM-1285) TCLP Toxic Characteristics Leach Procedure WTP Waste Treatment & Immobilization Plant INTRODUCTION The Department of Energy-Office of River Protection (DOE-ORP) is constructing the Hanford Tank Waste Treatment and Immobilization Plant (WTP) to treat radioactive waste currently stored in underground tanks at the Hanford site in Washington. The WTP that is being designed and constructed by a team led by Bechtel National, Inc. (BNI) will separate the tank waste into High Level Waste (HLW) and Low Activity Waste (LAW) fractions with the majority of the mass (~90%) directed to LAW and most of the activity (>95%) directed to HLW. Both the HLW and LAW will be vitrified in Joule Heated Ceramic Melters (JHCMs) for disposal. The JHCM is typically operated at a melt pool temperature of 1150°C. The slurry feed is introduced from the top of the melter and during operation the melt pool is almost entirely covered with unmelted feed termed the cold cap. The Hanford JHCMs are fitted with a patented bubbler system to agitate the melt pool, thus improving heat transfer to the cold cap and, therefore, feed processing rate. The current estimates and glass formulation efforts have been conservative in terms of achievable waste loadings. These formulations have been specified to ensure that the glasses are homogenous, contain essentially no crystalline phases, are processable in joule-heated, ceramic-lined melters and meet WTP Contract terms. The WTP’s overall mission will require the immobilization of tank waste compositions that are dominated by mixtures of aluminum (Al), chromium (Cr), bismuth (Bi), iron (Fe), phosphorous (P), zirconium (Zr), and sulphur (S) compounds as waste-limiting components. Glass compositions for these waste mixtures have been developed based upon previous experience and current glass property models. Recently, the DOE has initiated a testing program to develop and characterize HLW glasses with higher waste