SummaryOver several decades, site operations at what is now the U.S. Department of Energy's (DOE's) Idaho National Engineering and Environmental Laboratory have included nuclear reactor testing, reprocessing of spent nuclear fuel, and the storage, treatment, and disposal of the resultant radioactive and mixed wastes generated. Liquid, acidic, and radioactive high-level waste (HLW) and sodium bearing waste (SBW) from spent-fuel reprocessing operations have for the most part been calcined in the New Waste Calcining Facility (NWCF) and the earlier Waste Calcining Facility (WCF) to produce a dry granular waste form that is safer to store. However, about a million gallons of SBW remains uncalcined, and this liquid mixed waste, stored in tanks, does not meet current regulatory requirements for long-term storage and/or disposal. As a part of the Settlement Agreement between DOE and the State of Idaho, the tanks currently containing SBW are to be taken out of service by December 31, 2012, which requires the removal and treatment of the remaining SBW.Several potential options have been proposed for treating the SBW. Of those considered, vitrification received the highest weighted score against the criteria used. Beginning in fiscal year 2000, the INEEL HLW program embarked on a program for technology demonstration and development that would lead to conceptual design of a vitrification facility, based upon the liquid-fed melter technology, in the event that vitrification is the preferred alternative for SBW disposal. This program includes several separate activities that include, among others, waste-form development, process feed-stream design, and melter vitrification demonstration testing of the nonradioactive, surrogate SBW flowsheet. The first of the melter flowsheet tests conducted in support of INEEL's vitrification facility design is discussed below.The Pacific Northwest National Laboratory's (PNNL's) Research-Scale Melter (RSM) was used to conduct these initial melter-flowsheet evaluations. The RSM is a small (1/100-scale) joule-heated melter that is capable of processing melter feed on a continuous basis. This capability is key for:• developing/evaluating process flowsheets• characterizing relationships between feed composition and the properties of the final glass produced• establishing the fate and behavior of process effluent.This melter system's capability to produce glass in a continuous manner is also essential for estimating the behavior of a full-scale system. Moreover, the size of the RSM allows the impacts of process variables upon melter performance or glass quality to be quickly and efficiently evaluated without undue expense or waste generation.The experimental scope of this initial, 5-d, 120-h, SBW vitrification test was to evaluate the:• processing characteristics of the newly formulated SBW surrogate melter feed stream• acceptability of various SBW to glass-forming additive ratios• possible formation of a secondary sodium sulfate phase iv • effectiveness of sugar as a glass oxidation-state modifie...

SummaryThe loading of Idaho National Engineering and Environmental Laboratory sodium bearing waste (SBW) in glass will be limited by the allowable concentration of sulfate in the feed which is defined by the highest concentration that can be vitrified into glass at an acceptable rate without the accumulation of molten salt on the melt surface. This allowable concentration of sulfate in the feed is determined by many chemical (e.g., waste composition, chemistry of glass forming additives, waste loading, acid or reductant addition) and physical (e.g., melter-feed rate, plenum temperature, heat-transfer rate to the cold cap) parameters. This report documents the status of an ongoing study to determine the impacts of key processing parameters on the partitioning of sulfur species between the glass, a molten salt phase, and the off gas. As this study is continuing, the nature of these results is preliminary and incomplete. However, this report does give an indication of the relative importance of many parameters and the range of expected sulfur-partition coefficients during SBW vitrification.A series of tests was conducted to measure the partitioning of sulfur species between glass, the off gas, and a molten salt. In crucible tests, between 79 and 100% of the total sulfur was found to remain in the glass, and molten salts were not formed until the target concentration of sulfur in the glass exceeded roughly 1 mass% on an SO 3 basis. The use of high gas purge rates (e.g., 2300 ccm) in crucible tests decreased the fraction of sulfur in the glass to roughly 23% of that targeted. The influence of sugar concentration, heating rate, and starting feed pH were found to be minimal on the partitioning of sulfur species in these tests. Glass-forming additive composition was found to influence the formation of a salt layer. Details of the crucible tests are reported by Peeler et al. (2001).Three melter tests were performed with simulated SBW feed. The first test (EV-16-1999-1) was performed using the pilot-scale Envitco EV-16 melter at Clemson University in April 1999. The asbatched glass composition for this test contained 1.07 mass% of SO 3 . The measured concentration of sulfur in the glass produced was roughly 0.58 mass% based on SO 3 . No salt layer was observed during or after the test, suggesting that the remaining sulfur was driven to the off gas. However, power excursions occurred during the test, which occasionally brought the melt temperature to 1350°C. These excursions may have had a strong influence on the partitioning of sulfur during the test. Results of this test have yet to be published; highlights are described in Section 3.1.The second melter test (RSM-01-1) with simulated SBW feed was performed using the ResearchScale Melter (RSM) at Pacific Northwest National Laboratory in January 2001. This test was conducted in eight segments. The waste loading (30 to 35 mass% on a dry, non-volatile oxide basis), sulfur concentration (1.07 to 1.75 mass% based on SO 3 ), and sugar concentration (135 to 197 g/L of waste simu...

In order to further the goal of optimizing Hanford's HLW borosilicate flowsheet, a glass-formulation effort was launched to develop an advanced high-capacity waste form exhibiting acceptable leach and crystal-formation characteristics. A simulated C-106/AY-102 waste envelope inclusive of LAW pretreatment products was chosen as the subject of these nonradioactive optimization efforts. To evaluate this optimized borosilicate waste formulation under continuous dynamic vitrification conditions, a research-scale Joule-heated ceramic melter was used to demonstrate the advanced waste form's flowsheet. The main objectives of this melter test was to evaluate 1) the processing characteristics of the newly formulated C-106/AY-102 surrogate melter-feed stream, 2) the effectiveness of sucrose as a glassoxidation-state modifier, and 3) the impact of this reductant upon processing rates. v Summary In Response to a U.S. Department of Energy (DOE) Headquarters directive to conduct a technical review of alternatives for solidification of high-level waste (HLW) that could achieve major cost reductions with reasonable long-term risks, (a) the Tanks Focus Area (TFA) chartered an independent Review Team to evaluate cost incentives associated with modifications to: waste-form product requirements, waste-stream processing constraints, product glass composition, and the reference wastevitrification technology itself.

The loading of Idaho National Engineering and Environmental Laboratory sodium bearing waste (SBW) in glass will be limited by the allowable concentration of sulfate in the feed which is defined by the highest concentration that can be vitrified into glass at an acceptable rate without the accumulation of molten salt on the melt surface. This allowable concentration of sulfate in the feed is determined by many chemical (e.g., waste composition, chemistry of glass forming additives, waste loading, acid or reductant addition) and physical (e.g., melter-feed rate, plenum temperature, heat-transfer rate to the cold cap) parameters. This report documents the status of an ongoing study to determine the impacts of key processing parameters on the partitioning of sulfur species between the glass, a molten salt phase, and the off gas. As this study is continuing, the nature of these results is preliminary and incomplete. However, this report does give an indication of the relative importance of many parameters and the range of expected sulfur-partition coefficients during SBW vitrification. A series of tests was conducted to measure the partitioning of sulfur species between glass, the off gas, and a molten salt. In crucible tests, between 79 and 100% of the total sulfur was found to remain in the glass, and molten salts were not formed until the target concentration of sulfur in the glass exceeded roughly 1 mass% on an SO 3 basis. The use of high gas purge rates (e.g., 2300 ccm) in crucible tests decreased the fraction of sulfur in the glass to roughly 23% of that targeted. The influence of sugar concentration, heating rate, and starting feed pH were found to be minimal on the partitioning of sulfur species in these tests. Glass-forming additive composition was found to influence the formation of a salt layer. Details of the crucible tests are reported by Peeler et al. (2001). Three melter tests were performed with simulated SBW feed. The first test (EV-16-1999-1) was performed using the pilot-scale Envitco EV-16 melter at Clemson University in April 1999. The asbatched glass composition for this test contained 1.07 mass% of SO 3. The measured concentration of sulfur in the glass produced was roughly 0.58 mass% based on SO 3. No salt layer was observed during or after the test, suggesting that the remaining sulfur was driven to the off gas. However, power excursions occurred during the test, which occasionally brought the melt temperature to 1350°C. These excursions may have had a strong influence on the partitioning of sulfur during the test. Results of this test have yet to be published; highlights are described in Section 3.1. The second melter test (RSM-01-1) with simulated SBW feed was performed using the Research-Scale Melter (RSM) at Pacific Northwest National Laboratory in January 2001. This test was conducted in eight segments. The waste loading (30 to 35 mass% on a dry, non-volatile oxide basis), sulfur concentration (1.07 to 1.75 mass% based on SO 3), and sugar concentration (135 to 197 g/L of waste simulant) w...

SummaryOver several decades, site operations at what is now the U.S. Department of Energy's (DOE's) Idaho National Engineering and Environmental Laboratory have included nuclear reactor testing, reprocessing of spent nuclear fuel, and the storage, treatment, and disposal of the resultant radioactive and mixed wastes generated. Liquid, acidic, and radioactive high-level waste (HLW) and sodium bearing waste (SBW) from spent-fuel reprocessing operations have for the most part been calcined in the New Waste Calcining Facility (NWCF) and the earlier Waste Calcining Facility (WCF) to produce a dry granular waste form that is safer to store. However, about a million gallons of SBW remains uncalcined, and this liquid mixed waste, stored in tanks, does not meet current regulatory requirements for long-term storage and/or disposal. As a part of the Settlement Agreement between DOE and the State of Idaho, the tanks currently containing SBW are to be taken out of service by December 31, 2012, which requires the removal and treatment of the remaining SBW.Several potential options have been proposed for treating the SBW. Of those considered, vitrification received the highest weighted score against the criteria used. Beginning in fiscal year 2000, the INEEL HLW program embarked on a program for technology demonstration and development that would lead to conceptual design of a vitrification facility, based upon the liquid-fed melter technology, in the event that vitrification is the preferred alternative for SBW disposal. This program includes several separate activities that include, among others, waste-form development, process feed-stream design, and melter vitrification demonstration testing of the nonradioactive, surrogate SBW flowsheet. The first of the melter flowsheet tests conducted in support of INEEL's vitrification facility design is discussed below.The Pacific Northwest National Laboratory's (PNNL's) Research-Scale Melter (RSM) was used to conduct these initial melter-flowsheet evaluations. The RSM is a small (1/100-scale) joule-heated melter that is capable of processing melter feed on a continuous basis. This capability is key for:• developing/evaluating process flowsheets• characterizing relationships between feed composition and the properties of the final glass produced• establishing the fate and behavior of process effluent.This melter system's capability to produce glass in a continuous manner is also essential for estimating the behavior of a full-scale system. Moreover, the size of the RSM allows the impacts of process variables upon melter performance or glass quality to be quickly and efficiently evaluated without undue expense or waste generation.The experimental scope of this initial, 5-d, 120-h, SBW vitrification test was to evaluate the:• processing characteristics of the newly formulated SBW surrogate melter feed stream• acceptability of various SBW to glass-forming additive ratios• possible formation of a secondary sodium sulfate phase iv • effectiveness of sugar as a glass oxidation-state modifie...