[en] The TFA uses a systematic process for developing its annual program that draws from the tanks science and technology development needs expressed by the five DOE tank waste sites. TFA's annual program development process is iterative and involves the following steps: Collection of site needs; Needs analysis; Development of technical responses and initial prioritization; Refinement of the program for the next fiscal year; Formulation of the Corporate Review Budget (CRB); Preparation of Program Execution Guidance (PEG) for the next FY Revision of the Multiyear Program Plan (MYPP). This document describes the outcomes of the first phase of this process, from collection of site needs to the initial prioritization of technical activities. The TFA received site needs in October- December 2000. A total of 170 site needs were received, an increase of 30 over the previous year. The needs were analyzed and integrated, where appropriate. Sixty-six distinct technical responses were drafted and prioritized. In addition, seven strategic tasks were approved to compete for available funding in FY 2002 and FY 2003. Draft technical responses were prepared and provided to the TFA Site Representatives and the TFA User Steering Group (USG) for their review and comment. These responses were discussed at a March 15, 2001, meeting where the TFA Management Team established the priority listing in preparation for input to the DOE Office of Science and Technology (OST) budget process. At the time of publication of this document, the TFA continues to finalize technical responses as directed by the TFA Management Team and clarify the intended work scopes for FY 2002 and FY 2003

[en] Studies were performed to develop and test a glass formulation for immobilization of sodium-bearing waste (SBW), which is a high soda, acidic, high-activity waste stored at the Idaho National Engineering and Environmental Laboratory (INEEL) in 10 underground tanks. It was determined in previous studies that SBW?s sulfur content dictates its loading in borosilicate glasses to be melted by currently assumed processes. If the sulfur content (which is ∼4.5 mass% SO3 on a non-volatile oxide basis in SBW) of the melter feed is too high, then a molten, alkali-sulfate-containing salt phase accumulates on the melt surface. The avoidance of salt accumulation during the melter process and the maximization of sulfur incorporation into the glass melt were the main focus of this development work. A glass was developed for 20 mass% SBW (on a non-volatile oxide basis), which contained 0.91 mass% SO3, that met all the processing and product-quality constraints determined for SBW vitrification at a planned INEEL treatment plant?SBW-22-20. This paper summarizes the formulation efforts and presents the data developed on a series of glasses with simulated SBW.

[en] The TFA uses a systematic process for developing its annual program that draws from the tanks science and technology development needs expressed by the five DOE tank waste sites. TFA's annual program development process is iterative and involves the following steps: Collection of site needs; Needs analysis; Development of technical responses and initial prioritization; Refinement of the program for the next fiscal year; Formulation of the Corporate Review Budget (CRB); Preparation of Program Execution Guidance (PEG) for the next FY Revision of the Multiyear Program Plan (MYPP). This document describes the outcomes of the first phase of this process, from collection of site needs to the initial prioritization of technical activities. The TFA received site needs in October- December 2000. A total of 170 site needs were received, an increase of 30 over the previous year. The needs were analyzed and integrated, where appropriate. Sixty-six distinct technical responses were drafted and prioritized. In addition, seven strategic tasks were approved to compete for available funding in FY 2002 and FY 2003. Draft technical responses were prepared and provided to the TFA Site Representatives and the TFA User Steering Group (USG) for their review and comment. These responses were discussed at a March 15, 2001, meeting where the TFA Management Team established the priority listing in preparation for input to the DOE Office of Science and Technology (OST) budget process. At the time of publication of this document, the TFA continues to finalize technical responses as directed by the TFA Management Team and clarify the intended work scopes for FY 2002 and FY 2003

[en] The liquidus temperatures, TL, of rare earth-alumino-borosilicate glasses were measured as functions of glass composition. The TL values ranged from 1153 C to 1405 C. Three primary crystalline phases were identified in the study. The most frequently encountered was a rare earth silicate phase in which the TL values ranged from 1153 C to 1405 C. Al2O3 was encountered in glasses with an Al2O3:SiO2 mass ratio greater than 1, with TL values ranging from 1242 C to 1305 C. Alumino-silicate crystals were encountered as the primary phase in glasses with less than 43 mass% of mixed rare earth oxides (Ln2O3) with TL values between 1164 C and 1255 C. A linear relationship between total mixed rare earth oxide concentration and TL was found within all three primary phase fields. In the rare earth silicate primary phase field, normalizing the Ln2O3 with its mean ionic radius enhanced this linear relationship

[en] Preliminary models for liquidus temperature (TL) and temperature at 1 vol% crystal (T01) applicable to WTP HLW glasses in the spinel primary phase field were developed. A series of literature model forms were evaluated using consistent sets of data form model fitting and validation. For TL, the ion potential and linear mixture models performed best, while for T01 the linear mixture model out performed all other model forms. TL models were able to predict with smaller uncertainty. However, the lower T01 values (even with higher prediction uncertainties) were found to allow for a much broader processing envelope for WTP HLW glasses

[en] Recent tank retrieval and blending strategies at both the Savannah River Site (SRS) and Hanford have identified increased amounts of high-Al2O3 waste streams that are scheduled to be processed through their respective high-level waste (HLW) vitrification facilities. It is well known that the addition of small amounts of Al2O3 to borosilicate glasses generally enhances the durability of the waste glasses. However, at higher Al2O3 concentrations nepheline (NaAlSiO4) formation can result in a severe deterioration of the chemical durability of the slowly cooled glass near the center of the canister. Additionally, higher concentrations of Al2O3 generally increase the liquidus temperature of the melt and decrease the processing rate and thus result in a decreased waste loading in glass. Because of these effects, the maximum concentrations of Al2O3 in glasses have been restricted to the range of 17 wt% or lower. Pacific Northwest National Laboratory (PNNL), Savannah River National Laboratory (SRNL), and Khlopin Radium Institute (KRI) are jointly performing laboratory and scaled melter tests, through US Department of Energy, EM-21 Office of Waste Processing program, to develop glass formulations with increased Al2O3 concentrations. These glasses are formulated for specific DOE waste compositions at Hanford and SRS. The objectives are to avoid nepheline formation while maintaining or meeting waste loading and/or waste throughput expectations as well as satisfying critical process and product performance related constraints. This paper reports the results of recent tests of simulated Hanford HLW glasses containing up to 26 wt% Al2O3 in glass.

[en] Transformational melter technologies are being considered to support mission acceleration within the U.S. Department of Energy (DOE) complex. New glass formulations are required to take full advantage of the next generation melters, for example, the cold crucible induction melter (CCIM). The key advantage of CCIM technology over current reference technologies is its capability to provide higher processing temperatures, which can lead to an increased waste throughput rate by achieving higher waste loadings and by increasing the feed processing rate. Various waste compositions within the DOE complex were evaluated to determine their potential for successfully demonstrating the unique advantages of the CCIM technology. Glass formulations that satisfy a set of constraints for product quality and assumed CCIM processing conditions were developed for two Hanford waste streams, AZ-101 high-level waste (HLW) and AN-105 low-activity waste (LAW). Three glasses selected for AZ-101 HLW have waste loadings of 40, 42.5, and 45 wt%. The 45-wt% waste loading corresponds to a 22% increase from 37 wt%, which is the maximum expected waste loading based on the current reference formulation. One glass selected for AN-105 LAW has a waste loading of 31.3 wt% at 24 wt% Na2O in glass, which is a 14% increase from the current reference formulation maximum of 21 wt% Na2O. These four glasses are planned for scaled melter tests for initial demonstration of the CCIM technologies for Hanford wastes.

[en] This report documents the preliminary results of glass formulation and characterization accomplished within the finished scope of the EM-31 technology development tasks for WP-4 and WP-5, including WP-4.1.2: Glass Formulation for Next Generation Melter, WP-5.1.2.3: Systematic Glass Studies, and WP-5.1.2.4: Glass Formulation for Specific Wastes. This report also presents the suggested studies for eventual restart of these tasks. The initial glass formulation efforts for the cold crucible induction melter (CCIM), operating at ∼1200 C, with selected HLW (AZ-101) and LAW (AN-105) successfully developed glasses with significant increase of waste loading compared to that is likely to be achieved based on expected reference WTP formulations. Three glasses formulated for AZ-101HLW and one glass for AN-105 LAW were selected for the initial CCIM demonstration melter tests. Melter tests were not performed within the finished scope of the WP-4.1.2 task. Glass formulations for CCIM were expanded to cover additional HLWs that have high potential to successfully demonstrate the unique advantages of the CCIM technologies based on projected composition of Hanford wastes. However, only the preliminary scoping tests were completed with selected wastes within the finished scope. Advanced glass formulations for the reference WTP melter, operating at ∼1200 C, were initiated with selected specific wastes to determine the estimated maximum waste loading. The incomplete results from these initial formulation efforts are summarized. For systematic glass studies, a test matrix of 32 high-aluminum glasses was completed based on a new method developed in this study.

[en] At the Hanford Site in Richland, Washington, the path to site cleanup involves vitrification of the majority of the wastes that currently reside in large underground tanks. A Joule-heated glass melter is the equipment of choice for vitrifying the high-level fraction of these wastes. Even though this technology has general national and international acceptance, opportunities may exist to improve or change the technology to reduce the enormous cost of accomplishing the mission of site cleanup. Consequently, the U.S. Department of Energy requested the staff of the Tanks Focus Area to review immobilization technologies, waste forms, and modifications to requirements for solidification of the high-level waste fraction at Hanford to determine what aspects could affect cost reductions with reasonable long-term risk. The results of this study are summarized in this report

[en] Although the current baseline Hanford flowsheet for immobilizing low-activity waste (LAW) assumes borosilicate-based glass, opportunities exist to improve or change this baseline to reduce the current schedule and cost requirements of accomplishing the mission of site cleanup. Development of an alternative glass-forming system can lead to this goal of cost and schedule reduction through enhanced waste loading and higher plant throughput. The purpose of this project is to investigate the iron-phosphate glass system as an alternative for immobilizing Hanford LAW. Previous studies on the iron phosphate glass systems and their potential advantages for immobilizing Hanford LAW have been reviewed and technical uncertainties and data required before implementing this technology have been presented. A team of researchers and engineers from the MO-SCI Corporation, the Pacific Northwest National Laboratory, the Savannah River Technology Center, and the University of Missouri at Rolla has performed a series of tests to address some of the open questions about the potential use of iron phosphate glass for immobilizing Hanford LAW. The results of this team effort are summarized along with recommendations regarding the further laboratory study needs. Additional longer-term testing requirements for implementing the iron phosphate glass-based immobilization process at Hanford are also presented.