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DOE OSTI2013

System Performance Testing of the Pulse-Echo Ultrasonic Instrument for Critical Velocity Determination during Hanford Tank Waste Transfer Operations - 13584

The delivery of Hanford double-shell tank waste to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) is governed by specific Waste Acceptance Criteria that are identified in ICD 19 - Interface Control Document for Waste Feed. Waste must be certified as acceptable before it can be delivered to the WTP. The fluid transfer velocity at which solid particulate deposition occurs in waste slurry transport piping (critical velocity) is a key waste acceptance parameter that must be accurately characterized to determine if the waste is acceptable for transfer to the WTP. Washington River Protection Solutions and the Pacific Northwest National Laboratory have been evaluating the ultrasonic PulseEcho instrument since 2010 for its ability to detect particle settling and determine critical velocity in a horizontal slurry transport pipeline for slurries containing particles with a mean particle diameter of =14 micrometers (μm). In 2012 the PulseEcho instrument was further evaluated under WRPS' System Performance test campaign to identify critical velocities for slurries that are expected to be encountered during Hanford tank waste retrieval operations or bounding for tank waste feed. This three-year evaluation has demonstrated the ability of the ultrasonic PulseEcho instrument to detect the onset of critical velocity for a broad range of physical and rheological slurry properties that are likely encountered during the waste feed transfer operations between the Hanford tank farms and the WTP. (authors)

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DOE OSTI2012

Development of a Thermodynamic Model for the Hanford Tank Waste Operations Simulator - 12193

The Hanford Tank Waste Operations Simulator (HTWOS) is the current tool used by the Hanford Tank Operations Contractor for system planning and assessment of different operational strategies. Activities such as waste retrievals in the Hanford tank farms and washing and leaching of waste in the Waste Treatment and Immobilization Plant (WTP) are currently modeled in HTWOS. To predict phase compositions during these activities, HTWOS currently uses simple wash and leach factors that were developed many years ago. To improve these predictions, a rigorous thermodynamic framework has been developed based on the multi-component Pitzer ion interaction model for use with several important chemical species in Hanford tank waste. These chemical species are those with the greatest impact on high-level waste glass production in the WTP and whose solubility depends on the processing conditions. Starting with Pitzer parameter coefficients and species chemical potential coefficients collated from open literature sources, reconciliation with published experimental data led to a self-consistent set of coefficients known as the HTWOS Pitzer database. Using Gibbs energy minimization with the Pitzer ion interaction equations in Microsoft Excel,1 a number of successful predictions were made for the solubility of simple mixtures of the chosen species. Currently, this thermodynamic framework is being programmed into HTWOS as the mechanism for determining the solid-liquid phase distributions for the chosen species, replacing their simple wash and leach factors. Starting from a variety of open literature sources, a collection of Pitzer parameters and species chemical potentials, as functions of temperature, was tested for consistency and accuracy by comparison with available experimental thermodynamic data (e.g., osmotic coefficients and solubility). Reconciliation of the initial set of parameter coefficients with the experimental data led to the development of the self-consistent set known as the HTWOS Pitzer database. Using Microsoft Excel to formulate the Gibbs energy minimization method and the multi-component Pitzer ion interaction equations, several predictions of the solubility of solute mixtures at various temperatures were made using the HTWOS Pitzer database coefficients. Examples of these predictions are shown in Figure 3 and Figure 4. A listing of the entire HTWOS Pitzer database can be found in RPP-RPT-50703. Currently, work is underway to install the Pitzer ion interaction model in HTWOS as the mechanism for determining the solid-liquid phase distributions of select waste constituents during tank retrievals and subsequent washing and leaching of the waste. Validation of the Pitzer ion interaction model in HTWOS will be performed with analytical laboratory data of actual tank waste. This change in HTWOS is expected to elicit shifts in mission criteria, such as mission end date and quantity of high-level waste glass produced by WTP, as predicted by HTWOS. These improvements to the speciation calculations in HTWOS, however, will establish a better planning basis and facilitate more effective and efficient future operations of the WTP. (authors)

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DOE OSTI2012

Continued Evaluation of the Pulse-Echo Ultrasonic Instrument for Critical Velocity Determination during Hanford Tank Waste Transfer Operations - 12518

The delivery of Hanford double-shell tank waste to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) will be governed by specific Waste Acceptance Criteria that are identified in ICD 19 - Interface Control Document for Waste Feed. Waste must be certified as acceptable before it can be delivered to the WTP. The fluid transfer velocity at which solid particulate deposition occurs in waste slurry transport piping (critical velocity) is a key waste parameter that must be accurately characterized to determine if the waste is acceptable for transfer to the WTP. In 2010 Washington River Protection Solutions and the Pacific Northwest National Laboratory began evaluating the ultrasonic PulseEcho instrument to accurately identify critical velocities in a horizontal slurry transport pipeline for slurries containing particles with a mean particle diameter of >50 micrometers. In 2011 the PulseEcho instrument was further evaluated to identify critical velocities for slurries containing fast-settling, high-density particles with a mean particle diameter of <15 micrometers. This two-year evaluation has demonstrated the ability of the ultrasonic PulseEcho instrument to detect the onset of critical velocity for a broad range of physical and rheological slurry properties that are likely encountered during the waste feed transfer operations between the Hanford tank farms and the WTP. (authors)

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DOE OSTI2017

The Integrated Waste Feed Delivery Plan for the Direct Feed Low-Activity Waste Mission - 17160

In order to begin tank waste treatment and reduce the risk to the liquid waste cleanup mission, a plan to directly feed the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Low-Activity Waste (LAW) Vitrification Facility before other WTP facilities has been implemented. Implementation requires another facility, the Low-Activity Waste Pretreatment System (LAWPS), to generate LAW from tank waste supernatant, along with upgrades to the existing tank farm facilities to provide waste feed and receive process returns. The Integrated Waste Feed Delivery Plan (IWFDP) presents the strategy for reliably delivering compliant waste feed to the LAWPS and subsequently WTP to safely and efficiently accomplish the direct feed LAW (DFLAW) mission. Modifications to existing systems and installation of new systems will be coordinated to meet WTP startup, commissioning, and processing needs. The IWFDP presents the process approach, feed campaign plans, and a list of infrastructure projects required to upgrade the DST system in order to support DFLAW start-up and operations. (authors)

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DOE OSTI2017

Design, Fabrication and Start-up of Test Facilities for the LAWPS Full-Scale IX Column Test and Engineering Scale Test - 17418

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DOE OSTI2015

Plan for resolution of technical issues at the Hanford waste treatment and immobilization plant project - 15596

The Waste Treatment and Immobilization Plant (WTP) Project has a number of first-of-a-kind technical challenges that have necessitated expert analysis and testing activities to resolve. Since 2006, the U.S. Department of Energy (DOE) chartered two major WTP technical reviews. Most recently, in 2012, a number of top scientists and engineers conducted a review focused on the design and operability of WTP black cell and hard-to-reach areas. To provide leadership and oversight for resolution of the technical issues, DOE assembled a Design Completion Team composed of personnel from the DOE Office of River Protection (ORP), DOE contractors, and the national laboratories. The Design Completion Team established five technical sub-teams to address specific focus areas. The work of these sub-teams has evolved such that the project is now focused on eight technical issues referred to as T1 to T8. The WTP contractor has developed, and DOE has approved, plans for resolution of these issues. These plans form the basis for the Pretreatment (PT) Facility engineering work that will be performed over the coming years. This work, along with a corresponding update to the PT Facility safety basis, will result in an authorization to resume the engineering work necessary to complete the PT Facility design. (authors)

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DOE OSTI2016

Progress on Resuming Full Construction on the Waste Treatment and Immobilization Plant's High-Level Waste Facility - 16283

The U.S. Department of Energy (DOE) restricted certain engineering, procurement and construction work on the Waste Treatment and Immobilization Plant's (WTP) High-Level Waste (HLW) Facility in 2012 and early 2013 because of unresolved technical issues, and a need to align the nuclear safety basis with the design as the HLW Facility technical issues were resolved. The DOE Office of River Protection (ORP) needed a way to minimize the government's risk exposure, while continuing limited critical path construction work and resolving the technical and safety basis issues. ORP issued the Plan for Evaluation and Decision to Proceed for the High-Level Waste Facility in October 2013 to establish the process to evaluate the WTP contractor's progress on resolving the issues and to identify actions and deliverables needed to facilitate an ORP decision to resume production activities. This process provided for a phased resumption of HLW engineering, procurement and construction activities, with two decision points: Decision 1: Authorization to resume design/production engineering along with limited procurements and construction ramp-up. Decision 2: Full authorization to resume engineering, procurement and construction. In August 2014, ORP provided authorization for the WTP contractor to resume all engineering work necessary to finalize the design of the HLW Facility. The decision to proceed with production engineering in the HLW Facility was based on significant progress in resolving technical issues and improving work processes to align the HLW design and safety basis. ORP is working closely with the WTP contractor to facilitate decisions for resuming procurement of HLW Facility equipment with safety functions, and resuming full construction in the most complex process cells in the Facility. (authors)

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DOE OSTI2016

Progress on Resolution of Technical Issues at the Hanford Waste Treatment And Immobilization Plant Project - 16285

The U.S. Department of Energy's (DOE) Waste Treatment and Immobilization Plant (WTP) Pretreatment (PT) Facility has a number of first-of-a-kind technical challenges that have required additional expert analysis and testing activities to resolve. In 2006 an External Flowsheet Review Team identified 28 technical vulnerabilities with the plant design or future operability. Over a period of three months starting in September 2012, a number of top scientists and engineers conducted a review of the major technical issues associated with the design and operability of the WTP. These experts also provided independent advice on some of the broader challenges associated with completing the Hanford tank waste mission - highlighting the linkage between the physical and chemical properties of the tank waste and the PT Facility technical issues. In 2012 and early 2013 DOE's Office of River Protection (ORP) directed the WTP contractor to suspend production work on the Pretreatment Facility until the outstanding technical issues could be resolved and the nuclear safety basis could be updated and brought into alignment with any updates to the facility design and/or process flowsheet. Specific plans for resolving each the technical issues have been developed and significant progress has been made over the past year in identifying solution sets for each of the issues. The eight remaining technical issues (referred to as T1 to T8) are as follows: (T1) Hydrogen Gas Release from Vessel Solids; (T2) Potential Criticality in Pretreatment Facility Vessels; (T3) Hydrogen in Piping and Ancillary Vessels; (T4) Pulse-Jet Mixing and Control; (T5) Erosion and Localized Corrosion in WTP Vessels and Piping; (T6) Design Redundancy in Black Cells/In-Service Inspection; (T7) Black Cell Vessel Structural Integrity; (T8) Facility Ventilation. This paper provides a synopsis of the progress that has been made on resolving the Pretreatment technical issues over the past year, and how resolution of the issues will enable DOE to make an informed decision to resume design and production engineering for the Pretreatment Facility. (authors)

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DOE OSTI2016

Direct Feed Low Activity Waste (DFLAW) Program: Development, Progression and Risk Management - 16476

This Direct Feed Low-Activity Waste (DFLAW) Program paper describes the key programmatic elements to enable the startup of treatment and disposal of Hanford tank waste through a phased startup of the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Specifically the DFLAW Program consists of the Low- Activity Waste (LAW) vitrification facility, and the direct feed to LAW of treated tank farm supernatant from the Low-Activity Waste Pretreatment System (LAWPS). This document identifies the overall strategy, objectives, and processes of the U.S. Department of Energy (DOE), Office of River Protection (ORP) and all supporting DOE subcontractors, and describes the scope of the program elements. In addition gaps, risks, and opportunities to successful integration for commissioning of all needed systems and facilities to produce immobilized LAW product (ILAW) are described. The scope of the DFLAW Program extends up to the point that LAW Facility hot commissioning is complete and all DFLAW systems are fully operational. The DFLAW Program coordinates, integrates, and monitors all the activities necessary to successfully commission and start up the WTP LAW facility. This involves integrating the readiness of all the plant, personnel and program/procedures that support startup of hot commissioning of tank farms systems, WTP systems, waste treatment and disposal systems, and site utility, infrastructure and services. Multiple Hanford contractors have responsibilities to execute and perform scope under the umbrella of the DFLAW Program. The primary focus of the One System organization, comprised of WTP Project and Tank Operations Contract (TOC) personnel, is to manage the coordination and integration across the interfaces of the work scope described above. (authors)

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DOE OSTI2018

Implementing a Direct-Feed Low-Activity Waste Capability in the Hanford Waste Treatment Plant - 18332

The original design of the Waste Treatment and Immobilization Plant (WTP) requires that all waste be processed through the Pretreatment (PT) Facility in order to separate the low-activity waste and high-level waste streams. The U.S. Department of Energy (DOE) has developed a sequenced approach to completing the WTP Project, beginning with feeding some liquid waste directly to the Low-Activity Waste (LAW) Facility, bypassing the PT Facility. Sending low-activity waste from the tank farms to the LAW Facility is referred to as direct-feed LAW (DFLAW). Under this plan, low-activity waste will be pretreated in the Hanford tank farms for cesium and solids separation to meet LAW Facility waste acceptance criteria and produce an acceptable low-activity waste product. The waste feed will then be transferred to the LAW Facility where it will be immobilized in glass, poured into stainless steel containers, and then transported by truck to the Integrated Disposal Facility, a mixed low-level waste disposal site located in the Hanford 200 East Area. The DFLAW operation will deliver about 1 million gallons of double-shell tank waste for treatment each year of operation, and nominally produce 21 metric tons of immobilized low-activity waste glass per day. The resultant freed space in the double-shell tanks will support safe tank farm operations and staging of additional waste for treatment. In December 2016 DOE executed a contract modification and approved a change to the project's performance baseline to complete the LAW Facility, Balance of Facilities (BOF), and Analytical Laboratory (LAB) and incorporate modifications needed to allow direct feed of low-activity waste to the LAW Facility. The contract modification and revised performance baseline support completion and hot commissioning of WTP facilities needed for DFLAW operations is as early as January 2022. DOE has made significant progress on design, equipment procurements, and civil construction of modifications required to implement the DFLAW capability in the WTP, including progress on civil construction of a new effluent management facility, which will process secondary liquid waste resulting from LAW Facility vitrification operations. (authors)

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DOE OSTI2018

Process Control Approach to Implement High Waste Loading Glass Formulations for Hanford Low Activity Waste Vitrification - 18435

Acceptable glass formulations for vitrification of Hanford low activity waste (LAW) at The Hanford Tank Waste Treatment and Immobilization Plant (WTP) must meet a variety of product quality, processability, and waste loading requirements. The glass formulation development work underpinning the WTP baseline LAW glasses was captured in a vitrification process control approach developed by the Vitreous State Laboratory (VSL) and Atkins Energy Federal EPC, Inc. that permits the calculation of the glass formulation required for each particular batch of LAW delivered to the LAW vitrification facility. Since that time, we have developed a wide range of glass formulations that achieve considerably higher waste loadings and which therefore are more economically attractive in terms of reduced amounts of glass produced and decreased time for treatment. That work was done in support of the Department of Energy's Office of River Protection program that is examining options to optimize the LAW facility and LAW glass waste form. Implementation of these high waste loading formulations at the WTP requires the development of a new LAW vitrification process control algorithm, which is the subject of this paper. Waste loadings in LAW glasses are typically limited by either the alkali loading for LAW with low sulfate content or the SO{sub 3} loading for LAW with high sulfate content. In the former case, waste loadings are limited by refractory corrosion and glass corrosion on the vapor hydration test (VHT) and product consistency test (PCT), all of which tend to increase with higher alkali concentrations. In the latter case, waste loadings are limited by the formation of a molten sulfate phase in the melter, which has deleterious effects. The LAW vitrification process control strategy must mitigate these effects while optimizing waste loadings. Given the composition of any LAW stream, the new LAW vitrification process control algorithm permits the calculation of a suitable high waste loading glass composition and the required glass forming additives such that all processing, waste loading, and product quality requirements are met. This algorithm was developed from data for a large number of glasses that were formulated, and characterized with respect to a variety of properties affecting processability and product quality; many of these formulations were also subjected to melter testing to verify acceptable processing characteristics, processing rates, and the absence of secondary sulfate phase formation. This paper describes the development of the present algorithm, comparisons to the present lower waste loading baseline WTP process control approach, and plans for further development and testing. (authors)

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DOE OSTI2018

Testing Results from the Low Activity Waste Pretreatment System (LAWPS) Full-Scale Ion Exchange Column Test and Engineering Scale Integrated System Test - 18634

The U.S. Department of Energy (DOE), Office of River Protection's (ORP) primary mission is to retrieve and treat Hanford's tank waste and close the Tank Farms to protect the Columbia River. Mixed radioactive waste is stored in 177 underground tanks at the Hanford Site as reported in DOE/ORP 2003- 02, Environmental Impact Statement for Retrieval, Treatment, and Disposal of Tank Waste and Closure of the Single Shell Tanks at the Hanford Site, Richland WA, Inventory and Source Term Data Package. The 177 underground tanks are estimated to contain about 56 million gallons of waste. The Low Activity Waste Pretreatment System (LAWPS) Project provides for the early production of immobilized low activity waste (ILAW) by feeding LAW directly from Tank Farms to the Hanford Waste Treatment Plant's (WTP's) LAW Facility, bypassing the Pretreatment Facility. Prior to the transfer of feed to the WTP LAW Vitrification Facility, tank supernatant waste will be pretreated in the LAWPS to meet the WTP LAW waste acceptance criteria. The LAWPS will also facilitate the return of secondary liquid wastes from the WTP LAW Vitrification Facility to the Tank Farms. In November of 2015 DOE's Tank Operations Contractor, Washington River Protection Solutions (WRPS), awarded a contract to the AECOM team to design, fabricate and operate two test platforms to generate performance data at two different scales and demonstrate technology maturation. The first platform models the ion exchange (IX) columns at full scale, and the second platform models the integrated flowsheet (cross flow filter (CFF) and IX) at 1/9. scale. Overarching technical objectives of performing the full-scale ion exchange test and the engineering-scale integrated test are to: 1. Test interactions between unit process operations; 2. Test removal of non-radioactive cesium from process stream; 3. Test removal of undissolved solids from process stream; 4. Confirm operational flow rate range and stability; 5. Confirm volumetric throughput of waste stream over flow operating range; 6. Confirm range of process temperatures over planned operating range; 7. Establish system hydraulics and process criteria; 8. Coordinate key control and monitoring components; 9. Establish treated product chemistry meets requirements (cesium, solids, and pH); and 10. Test the hazard control strategy for a no flow condition through the IX column. Data collected during testing will be used by WRPS to validate the preliminary design, inform the final design of the permanent plant equipment, and demonstrate that the critical technology elements have advanced to a technology readiness level of 6 (prototypical system validation in a relevant environment). Testing on both platforms started in fall of 2016 generating NQA-1 data. This paper covers test results from the first five phases of testing on the 1/9. scale integrated test platform. A further three phases of testing are currently being executed, these including a 5.6 M sodium simulant containing foulant, a high viscosity simulant and finally a run performed with a lower Cs concentration (all earlier tests were spiked to 4 x Cs to reduce volume and cost). Results from these tests were not available at the time of writing available. Results are also presented from the full scale IX testing. Eight test were performed covering column loading, elution and regeneration; column loading, elution and regeneration with upflow displacement; IX column loading and gas migration; resin removal; solids accumulation; and IX column emergency recirculation and vent. (authors)

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DOE OSTI2019

Career Development through Discreet Simulation Modeling - 19009

The cleanup mission of the Department of Energy (DOE) Office of River Protection (ORP) at the Hanford Site is to immobilize 212,000 m3 (56 million gallons) of nuclear waste, currently stored in 177 underground tanks, at the Waste Treatment and Immobilization Plant (WTP) and associated supplemental treatment facilities. Waste transfers to and from the WTP utilize the intricate Hanford Waste Feed Delivery (WFD) system, a network composed of: double-shell tanks (DSTs), single shell tanks (SSTs), the effluent treatment facility (ETF), a large number of pumps, valves, and leak detectors, and thousands of feet of underground transfer lines. This equipment must be prepared to safely and reliably transfer waste to the WTP. This study used discrete event simulation modeling to explore the behavior of the waste transfer system to identify areas of improvement. Two models and their subsequent results are presented: the Effluent Treatment Facility and the next-to-be-retrieved single-shell tanks (A/AX Farms). This study focused on identifying throughput bottlenecks, operational constraints, choke-point analysis, and redundancy in equipment, process design, and operational strategy. Analysis performed on the ETF OR Model indicated that the existing facility operation strategy will not result in a sufficient throughput to prevent WTP melter idling. Furthermore, in the absence of equipment failures, the facility was still shown to be unable to reach the required throughput to prevent melter idling. It is concluded that ETF system maintenance events are currently the main bottlenecks in the ETF facility. Analysis performed on the SST (A/AX) OR model indicate that the main drivers of the retrieval schedule are the hard retrieval start dates for each SST tank. In addition, it was concluded that operating the ventilation trains in parallel results in 15 times less retrieval interruptions and shortens the retrieval durations. (authors)

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DOE OSTI2025

Advanced Computational Modeling of High-Level Waste Vitrification at the Hanford Site

The U.S. Department of Energy (DOE) has selected vitrification for stabilizing legacy tank waste at the Hanford site, where radioactive waste from plutonium production was historically stored in underground tanks. This waste will be separated into low-activity waste (LAW) and high-level waste (HLW) fractions and processed at the Waste Treatment and Immobilization Plant (WTP). At WTP, glass melters are used for the vitrification of radioactive tank waste, transforming it into a stable borosilicate glass form for safe long-term storage. The melter vessel is constructed from highly durable and heat-resistant materials, where the vitrification process occurs. The main regions that are modeled are the melt pool, plenum, cold cap, riser/discharge chamber, and surrounding structure with insulation layers. Forced convection induced by air bubblers at the base of the melter ensure uniform temperature distribution and provide heat to the cold cap layer. The cold cap is a region of reacting batch feed that floats on top of the molten glass and is where the batch-to-glass reactions occur. Joule heating provided by electrodes mounted along the vertical walls of the melter and immersed directly in the glass, generates the necessary heat for the net endothermic conversion processes that occur in the cold cap. The high temperatures, radioactivity, and opaque nature of the glass prevent direct observation inside the melters. Therefore, computational models are essential for providing insight into factors that affect melter throughput. Thermocouples in the plenum provide operators with plenum temperature measurements. Operational adjustments include bubbling rate, voltage supplied to the electrodes, feed adjustments, and glass removal rate. Different computational fluid dynamics (CFD) models have been developed, each serving a specific purpose. There are CFD models of different scale melters, as well as models that capture the two-phase flow interfaces of rising bubbles in the molten glass or models with a simplified molten glass region so that the surrounding structure and plenum can be feasibly incorporated. Pilot-scale melter models have been developed to serve as validation of the methods employed in the simulation of the full-scale WTP melters. Models incorporating resolved bubbling are used to develop momentum source terms to implement into a single phase, multi-region, steady-state flow model that is being validated by measured process parameters such as glass production rate, voltage, input power, plenum temperatures, etc. The resolved bubbling model uses the multiphase volume of fluid approach to model the system with a high-resolution interface capturing scheme to maintain sharp interfaces between the molten glass and the air phase. The suite of CFD models is continually being improved to incorporate more realistic physics and achieve faster turnaround time. For example, an incremental controller is implemented to automatically adjust electrode voltage within the simulation to a molten glass set point temperature of 1150°C. Newer models feature improved meshes to ensure conformal meshes between regions and eliminate unnecessary mesh refinement in areas that are not of interest (such as boundary layers in offgas ports). Instead of explicitly modeling the structural, refractory, and insulation layers of the melter, a thermal resistance approach is used with published correlations used for boundary conditions. The development of robust and efficient CFD models will be instrumental in enabling the WTP to successfully fulfill its mission of safely stabilizing legacy nuclear waste.

12 - MGMT OF RADIOACTIVE AND NON-RADIOACTIVE WASTE↗

DOE OSTI2021

Characterization of the Sulfur-Saturated Melt Versions of the HFG1 Study Glasses

The U.S. Department of Energy (DOE) is responsible for building the Hanford Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site in Washington to remediate 55 million gallons of radioactive waste that is temporarily stored in 177 underground tanks. The Office of River Protection (ORP) has requested that the Savannah River National Laboratory (SRNL) contribute to current glass studies to support successful startup of the WTP, due to SRNL’s recognized capabilities and expertise for glass waste form development. As part of this effort, the Pacific Northwest National Laboratory (PNNL) is developing, batching, and fabricating simulated high-level waste (HLW) glasses to generate the associated property data needed to validate or identify areas of potential characterization improvements in the current glass property/ composition models. Currently, the models cover only a small fraction of the waste compositions projected in the Hanford tank farm; therefore, the models must be expanded to include high fluoride compositions to successfully complete the WTP mission. SRNL support of this work is defined in the Task Technical and Quality Assurance Plan (TTQAP). This report provides results from the chemical analyses of a series of sulfur-saturated melt (SSM) versions of simulated nuclear waste glasses fabricated at PNNL. The glasses were selected as part of a broader study of the influence of glass composition on chemical durability, sulfur retention, and other properties. The glasses were designated the High Fluoride Glasses-1 (HLG1).

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DOE OSTI2021

Product Consistency Test Results for the HFG1 Glasses

The U.S. Department of Energy (DOE) is responsible for building the Hanford Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford site in Washington to remediate 55 million gallons of radioactive waste that is temporarily stored in 177 underground tanks. The Office of River Protection (ORP) has requested that the Savannah River National Laboratory (SRNL) contribute in areas of recognized capabilities and expertise for glass waste form development to support successful startup of the WTP. As part of this effort, the Pacific Northwest National Laboratory (PNNL) is developing, batching, and fabricating simulated high-level waste (HLW) glasses to generate the associated property data needed to validate or identify areas of potential characterization improvement in the current glass property/composition models. Currently, the models cover only a small fraction of the waste compositions projected in the Hanford tank farm; therefore, the models must be expanded to include high fluoride compositions to successfully complete the WTP mission. SRNL support of this work is defined in the Task Technical and Quality Assurance Plan (TTQAP). This report provides the results of the Product Consistency Test (PCT) leachates from the High Fluoride Glasses-1 (HFG1), a series of simulated nuclear waste glasses fabricated at PNNL. The series included quenched (Q) and canister-centerline cooled (CCC) versions of the glasses. The glasses were selected as part of a broader study of the influence of glass composition on chemical durability, sulfur retention, and other properties. These data will be used to validate or identify areas of potential characterization improvements in the current glass property/composition models.

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DOE OSTI2015

Lifecycle assessment of microalgae to biofuel: Comparison of thermochemical processing pathways

Microalgae are currently being investigated as a renewable transportation fuel feedstock based on various advantages that include high annual yields, utilization of poor quality land, does not compete with food, and can be integrated with various waste streams. This study focuses on directly assessing the impact of two different thermochemical conversion technologies on the microalgae to biofuel process through life cycle assessment. A system boundary of a “well to pump” (WTP) is defined and includes sub-process models of the growth, dewatering, thermochemical bio-oil recovery, bio-oil stabilization, conversion to renewable diesel, and transport to the pump. Models were validated with experimental and literature data and are representative of an industrial-scale microalgae to biofuel process. Two different thermochemical bio-oil conversion systems are modeled and compared on a systems level, hydrothermal liquefaction (HTL) and pyrolysis. The environmental impact of the two pathways were quantified on the metrics of net energy ratio (NER), defined here as energy consumed over energy produced, and greenhouse gas (GHG) emissions. Results for WTP biofuel production through the HTL pathway were determined to be 1.23 for the NER and GHG emissions of -11.4 g CO 2-eq (MJ renewable diesel) -1 . WTP biofuel production through the pyrolysis pathway results in a NER of 2.27 and GHG emissions of 210 g CO2 eq (MJ renewable diesel)-1. The large environmental impact associated with the pyrolysis pathway is attributed to feedstock drying requirements and combustion of co-products to improve system energetics. Discussion focuses on a detailed breakdown of the overall process energetics and GHGs, impact of modeling at laboratory- scale compared to industrial-scale, environmental impact sensitivity to engineering systems input parameters for future focused research and development and a comparison of results to literature.

09 BIOMASS FUELS↗

DOE OSTI2019

Formulation of high-Al2O3 waste glasses from projected Hanford waste compositions

Not Available

Kroll, Jared O.↗