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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

In-Situ 27Al NMR Spectroscopy of Aluminate in Sodium Hydroxide Solutions Above and Below Saturation with Respect to Gibbsite

Aluminum hydroxide (Al(OH)3, gibbsite) dissolution and precipitation processes in alkaline environments play a commanding role in aluminum refining and nuclear waste processing, yet mechanistic aspects underlying sluggish kinetics during crystallization have remained obscured due to a lack of in situ probes capable of isolating incipient ion pairs. At a molecular level Al is cycling between tetrahedral (Td) coordination in solution to octahedral (Oh) in the solid. We explored dissolution of Al(OH)3 that prepared variably saturated aluminate (Al(OH)4 -)-containing solutions under alkaline conditions (pH > 13) with in-situ 27Al magic angle spinning (MAS)-nuclear magnetic resonance (NMR) spectroscopy, and interrogated the results with ab initio molecular dynamics (AIMD) simulations complemented with chemical shift calculations based on high level theory. The collective results highlight the overall stability of the solvation structure for Td Al in the Al(OH)4 - oxyanion as a function of both temperature and Al concentration. The observed chemical shift did not change significantly even when the Al concentration in solution became supersaturated upon cooling and limited precipitation of the octahedral Al(OH)3 phase occurred. However, subtle changes in Al(OH)4 - speciation correlated with the dissolution/precipitation reaction were found. AIMDinformed chemical shift calculations indicate that measurable perturbations should begin when the Al(OH)4 -?Na+ distance is less than 6 Å, increasing dramatically at shorter distances, coinciding with appreciable changes to the electrostatic interaction and reorganization of the Al(OH)4 - solvation shell. The integrated findings thus suggest that, at conditions incipient to and concurrent with gibbsite crystallization, nominally expected contact ion pairs are insignificant and instead medium-range (4 – 6 Å) solvent-separated Al(OH)4 -?Na+ pairs predominate. Moreover, the fact that these medium-range interactions bear directly on resulting gibbsite characteristics was demonstrated by detailed microscopic and X-ray diffraction analysis, and by progressive changes in the FWHM of the Oh resonance, as measured by in-situ NMR. Sluggish gibbsite crystallization may arise from the activation energy associated with disrupting this robust medium-range ion pair interaction.

Graham, Trenton R.↗
DOE OSTI2023

Evaluation of a Sulfate Solubility Limit Greater Than 0.65 Weight Percent in Sludge Batch 10 Glasses

Previous laboratory-scale crucible testing with batch chemicals confirmed that the sulfate (SO 4 2- ) limit for Sludge Batch 10 (SB10) was 0.65 weight percent (wt.%) in glass. This limit signifies that 0.65 wt.% SO 4 2- can be retained in the glass without the formation of a sulfate phase. The Defense Waste Processing Facility imposes this constraint in the Material Tracking Program. Based on preliminary calculations to support the Material Tracking Program, it was anticipated that transfer volumes of the monosodium titanate/sludge solids (MST/SS) stream from the Salt Waste Processing Facility (SWPF) may need to be reduced to maintain projected sulfate concentrations below 0.65 wt.% in glass. Savannah River Mission Completion requested that the Savannah River National Laboratory perform additional sulfate testing to determine whether a sulfate solubility limit greater than 0.65 wt.% is feasible for SB10, which could allow for higher transfer volumes of the MST/SS stream. This report documents the results of the testing at higher sulfate concentrations for the glass composition region defined by the most recent SB10 projection (November 2022) and Frits 473 and 625. Frit 473 was recommended for SB10 and Frit 625 was used during SB9 processing and the SB9 to SB10 transition. A total of twenty-one glass compositions were developed based on the expected compositional variables, which include sludge-only (SO) and coupled processing with the SWPF, waste loading (WL), and frit composition. The target sulfate concentrations were varied from 0.65-0.85 wt.% at 32 and 40% WL. Each glass was prepared from reagent grade chemicals and melted at 1150 °C. Visual observations were used to confirm the presence of a sulfate salt phase on the cooled glass surfaces. Representative samples of each glass were submitted for chemical composition analysis by inductively coupled plasma-optical emission spectroscopy and Cs analysis by inductively coupled plasma-mass spectrometry. Overall the majority of mean measured values are consistent with the target values for each major oxide of interest with less than 5% error. The percent errors for the measured SO 4 2- concentrations are generally less than 10%, which is comparable with previous sulfate solubility study measurements and acceptable. Only the SO glasses based on Frit 625 formed a sulfate phase at a 0.80 wt.% SO 4 2- target concentration at both 32 and 40% WL. The remainder of the glasses did not form a sulfate layer. Due to the formation of the sulfate phase, the limit is conservatively set at 0.70 wt.% based on the measured sulfate concentrations of 0.71 wt.% and 0.75 wt.% for these two glasses. None of the SO or coupled operation glasses based on Frit 473 formed a sulfate salt phase, which supports a sulfate limit of 0.80 wt.%. The following SO 4 2- concentration limits are recommended during SO and coupled SB10 processing: (1) 0.70 wt.% during processing with Frit 625, and (2) 0.80 wt.% during processing with Frit 473.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Evaluating Liquid Waste Transfers and their Impacts to the SRS Tank Farms to Support Operations and Closure

BACKGROUND • SRMC mission critical milestones – 34 million liters (9 million gallons) Salt Waste Processing Facility (SWPF) Processing Rate – Accelerated Waste Tank Closures • Results in an increase in Tank Farm transfers • Barriers – Equipment failures, replacements, and adjustments – Weather – Procedure development – Outside facility changes How has the Tank Farm adapted to meet these milestones? By improving the transfer evaluation process

B↗
DOE OSTI2020

Session 078 - Panel: Start-Up of Three Major DOE Treatment Facilities -SWPF, IWTU and DFLAW (2/2) (R2.4)

This panel focused on the successes and challenges of the DOE High-Level radioactive tank waste management program, with an emphasis on the completion of construction and startup of three major treatment facilities - the Salt Waste Processing Facility (SWPF) at Savannah River, the Integrated Waste Treatment Unit (IWTU) at Idaho, and Direct Feed Low-Activity Waste (DFLAW) processing at Hanford. As a companion to Session 23, DOE managers and federal project directors discussed the status of facility startup efforts from a federal management and oversight perspective, highlighting readiness planning, challenges and lessons learned. Panelists with presentations: Transitioning Oversight: A Project Becomes an Operating Facility (James Folk); Tools for SU/C (Tom Fletcher); Startup and Commissioning -Integrate Waste Treatment Unit-Federal Perspective (Joel Case)

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DOE OSTI2025

Cesium exhibits different mesoscale segregation and ion pairing than lithium, sodium, or potassium in concentrated alkaline aqueous nitrite solutions

Understanding ion pairing in concentrated alkaline electrolytes facilitates the prediction and control of chemical processes in nuclear waste. While sodium is the dominant alkali metal in such systems, cesium often exhibits distinct bulk behavior relative to lighter alkali cations. Aqueous mixtures of cesium hydroxide and sodium nitrite were compared to alkali hydroxide analogs using small-angle x-ray scattering, revealing that cesium disrupts the sodium nitrite electrolyte structure, forming cesium-rich domains. This mesoscale segregation contrasts with the near-ideal mixing observed in other mixed hydroxide–nitrite systems. Raman spectroscopy indicates cesium–nitrite ion pairing, evidenced by vibrational shifts distinct from those associated with sodium. Multinuclear magnetic resonance spectroscopy further supports cesium–nitrite and cesium–hydroxide association, revealing a distinct local environment for nitrite in cesium-containing solutions. Together, these findings show that cesium promotes a unique solution structure dominated by specific ion pairing within segregated domains. This structural organization may influence radical generation pathways in high-ionic-strength alkaline media relevant to nuclear waste processing and management.

Nienhuis, Emily T. [Pacific Northwest National Lab↗
DOE OSTI2019

Summary Report for the Analysis of the Sludge Batch 8 (Macrobatch 10) DWPF Pour Stream Glass Sample

In order to comply with the Defense Waste Processing Facility (DWPF) Waste Form Compliance Plan for Sludge Batch 8, Savannah River National Laboratory (SRNL) personnel characterized a pour stream sample that was collected while canister S04274 was being filled. This report summarizes the results of the compositional analysis for reportable oxides and radionuclides, and the normalized Product Consistency Test (PCT) results. The PCT responses indicate that the DWPF produced glass is significantly more durable than the Environmental Assessment glass. Results and further details are documented in SRNL-STI-2018- 00699, “Analysis of the Sludge Batch 8 (Macrobatch 10) DWPF Pour Stream Glass Sample.”

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DOE OSTI2019

Results of the Supplementary Analyses of Salt Batch 10 and 11 Samples

Supplementary analyses of material from the Interim Salt Disposition Project (ISDP) Salt Batch (SB) 10 and Salt Batch 11 (SB11) samples were analyzed beyond what is described in previous reports. These additional analyses are required to verify these materials meet Salt Waste Processing Facility (SWPF) Waste Acceptance Criteria (WAC) feed requirements. The stored SB10 and SB11 samples have been analyzed without filtering and the results found to be very similar to the previous filtered analyses performed for SB10 and SB11. The only result of significant difference is the wt% insoluble solids result for the SB11 sample. It would appear the newer method of analyzing larger volumes gives more accurate measurements for solutions with low quantities of solids.

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DOE OSTI2020

Calculation of Glycolate Concentration Factors Across the 242-25H (3H) Evaporator System

Two models were developed to predict glycolate concentration factors across the 242-25H (3H) Evaporator system. The first model, identified as the Unrestricted Evaporation Model, was designed to evaluate concentration of typical 3H feed material to relatively high densities in order to calculate the concentration factor of glycolate in a given feed stream. This model may be used to understand the potential of glycolate to concentrate from a generic feed material through the 3H system. The second model, identified as the Holistic Evaporation Model, was designed to evaluate the evaporation of dilute, glycolate-containing Defense Waste Processing Facility (DWPF) waste with the requirement that high silicon concentrations typical of recycle material require dilution to adhere to current technical safety requirements. This model may be used to understand the potential of glycolate from DWPF recycle material to concentrate as a result of feeding through the 3H system.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1979

Research recommendations

The research and development sequences and priorities for CELSS development were established for each of the following areas: nutrition and food processing, food production, waste processing, systems engineering/modeling, and ecology-systems safety.

Source record↗
NASA NTRS1982

Controlled Ecological Life Support System: Research and Development Guidelines

Results of a workshop designed to provide a base for initiating a program of research and development of controlled ecological life support systems (CELSS) are summarized. Included are an evaluation of a ground based manned demonstration as a milestone in CELSS development, and a discussion of development requirements for a successful ground based CELSS demonstration. Research recommendations are presented concerning the following topics: nutrition and food processing, food production, waste processing, systems engineering and modelling, and ecology-systems safety.

Mason, R. M.↗
NASA NTRS1981

The CELSS program - An overview of its structure and use of computer modelling

NASA has initiated a research program, CELSS, directed at the acquisition of the knowledge and technology required for the development of an autonomous, regenerative life support system. The program is structured to promote effective, cooperative research in fundamental, applied and engineering science. The initial research thrusts involve investigations into problems of food production, waste processing and system control and integration. In the area of food production both conventional, higher plant-based processes as well as chemosynthetic food production technologies are being investigated. Alternative waste processing procedures, both biological and physicochemical, are being examined. Computer based modelling as an aid to design and analysis is an integral part of the approach to system control and management. A mass balance model depicting the flow of elemental mass in a conceptualized closed, regenerative life support system is described.

Averner, M. M.↗
DOE OSTI2020

Qualification of Processing Batches for Tank Closure Cesium Removal Through In-Tank Batch Contact Testing - 20470

The Tank Closure Cesium Removal (TCCR) process at the Savannah River Site (SRS) is currently processing waste from Tank 10H, generating decontaminated salt solution that is sent to Tank 11H. Transfers out of Tank 11H are then disposed of on site as a grout wasteform in the SRS Saltstone Processing Facility. This is a full-scale demonstration of the use of Crystalline Silicotitanate (CST) for the decontamination of aqueous nuclear waste supernate. CST primarily removes cesium from the high sodium alkaline feed, but also adsorbs strontium, actinides, and some other trace metals. The TCCR unit is an at-tank set of four ion exchange columns, with two typically being operated in series during waste processing. Tank 10H is serving a dual function as both the salt dissolution tank as well as the feed tank for the TCCR system. Prior to operation of TCCR, Tank 10H must undergo dissolution campaigns, dissolving the salt cake to form an aqueous salt solution (supernate). After each dissolution campaign, the supernate created must be qualified prior to processing through the TCCR system. Qualification includes detailed characterization of the supernate as well as in-tank batch contact tests to determine the equilibrium loading of Cs-137 on the CST ion exchange media (IONSIV{sup TM} R9120-Ba). In support of the in-tank batch contact testing, Savannah River National Laboratory (SRNL) developed a CST sample holder, also referred to as a 'tea-bag', to hold a measured amount (∼0.1 grams) of pretreated CST between stainless steel screens. The tea-bag fits within a standard stainless steel sample vial that has been modified to allow the flow of supernate to the CST. This sample holder is then immersed in the waste tank allowing free contact between the CST beads and the surrounding liquid, at an effectively infinite liquid-to-solid phase ratio. A pair of tea-bags are deployed in the tank for a period of 10 days for each batch, after which the CST is recovered, digested, and analyzed to determine the loading of cesium isotopes on the CST. This result then supports the TCCR column thermal loading limits for processing as part of the TCCR safety basis. This paper will discuss the design and testing of the CST sample holder, as well as results from the first few batches of waste qualified and subsequently processed through the TCCR system. In addition, results from analyses of Tank 11H samples, showing decontamination of the product will be included. (authors)

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DOE OSTI2019

Development of a Testbed for Pipeline Flushing - 19409

Pipelines which carry radioactive waste within the DOE complex should be properly flushed, particularly in the cases where stationary or moving beds of solid sediment occur, or lines are prone to hydrogen gas buildup. Present guidelines establish a minimum for the amount of water used for post-transfer flushing operations to achieve satisfactory cleaning of pipelines. However, further studies are needed to limit the amount of water used for flushing operations, thus minimizing the consequent downstream waste. These efforts are significantly helpful to DOE waste remediation sites by preserving tank storage, preventing additional waste processing, and minimizing dilution and changes in waste chemistry. An experimental pipe loop designed for study of non-Newtonian slurry flushing is currently being developed at the Florida International University (FIU). The testbed is designed to investigate parameters that effect the efficiency of flushing operations. The objective is to find flush velocity values/modes which lead to satisfactory cleaning of transport lines with a minimum amount of water usage. The developed methodologies will be streamlined according to the demands from both Hanford and Savannah River sites. A test matrix containing parameters such as pipeline length, flow rate, and simulant composition (solid concentration, rheology, particle size and density) has been developed. In the initial phase of testing, material composition and loop length will be fixed to a mixture of 17 wt% kaolin in water (to attain density, viscosity, and yield stress in the applicable range to operations at Savannah River and Hanford sites) and 165 feet, respectively. This matrix provides a parametric study on the flush velocity. Prescribed velocities in this test matrix comply with the maximum and minimum recommended flush velocity values by the flushing guidelines for Hanford waste (RPP-RPT-59600, Rev. 0, SRNL-STI-2015-00014, TFC-ENG-STD-26, REV C-1). Efforts will focus on creating repeatable sediment beds inside the pipeline in both fully-flooded and gravity-drained systems. Bed characterization (i.e., measurement of sediment height, solids concentration, and rheology) will be conducted to ensure consistency of initial conditions between tests. A combination of Pulse-Echo technique, Coriolis meter, and optical inspections will be used to accomplish initial bed characterization (ensuring consistency between tests), control/monitor density variations (initial bed creation, flush velocity control, and post-flush evaluations), and serve as reference (validation of PulseEcho and pipe surface cleanness evaluation), respectively. This paper will present the details of the development of the test loop and the test matrix. (authors)

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DOE OSTI2023

Evaluation of High Level Waste Sludge Processing Behavior

The U.S. Department of Energy’s (DOE) Hanford Site has 177 underground storage tanks that contain wastes from past nuclear fuel reprocessing and waste-management operations. Over 20% of this waste is in the form of an insoluble sludge that will require slurry modification before its transfer to the Waste Treatment and Immobilization Plant (WTP). Specific WTP acceptance criteria for waste feed delivery describe the physical and chemical characteristics of the waste that must be met before the waste is transferred to the WTP. One challenging requirement relates to the undissolved solids (UDS) composition in a waste feed because the waste contains solid particles that settle, and their concentration and relative proportion can change during the transfer of the waste in individual batches. A key uncertainty is the ability to transfer and mix wastes with large variations in UDS concentrations and resulting settling rates. To address this uncertainty, a number of small scale mixing and settling tests have been conducted to determine the mobilization performance of variable chemistry simulants. Comparison of the size and density of the particulate for each simulant to that of southeast area Hanford sludge was made using metrics for particle mobilization, suspension, settling, and pipeline transfer where dependance on particle size and density may be different, including: 1. Settling velocity, 2. Critical shear stress for erosion, 3. Just-suspended impeller speed, and 4. Pipeline critical transport velocity. Existing high-level waste sludge data has shown the effect that increasing Al concentration has on resulting settled solids. This differential settling of particles in the sludge has the possibility of resulting in solids segregation during feed preparation and uneven particle distribution during pipeline transportation or mixer jet pump operations. Understanding the predictive capabilities of HLW solids settling and transport as well as potential remedies for addressing disparate sludge behaviors can help provide technical guidance during HLW flowsheet planning.

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DOE OSTI2019

Peroxide Decomposer Module Catalyst Testing to Support Preparations for Increased Demand - 19052

The Hanford Site Effluent Treatment Facility's (ETF) mission is to receive, treat, and dispose of liquid effluents from on-site programs and projects. Its roles in the management and mitigation of tank waste volume is integral to the overall Hanford tank farms mission, as tank space is limited. ETF's role will become even more essential as the Direct-Feed Low Activity Waste process comes online at the Waste Treatment and Immobilization Plant (WTP). In order to accommodate the additional liquid effluent streams, the ETF will undergo a number of facility and equipment upgrades. Included in this is the reinstatement of the Peroxide Decomposer Module (PDM) into the ETF's main treatment train. The PDM is used to remove any residual hydrogen peroxide not fully consumed in the preceding ultraviolet/oxidation (UV/OX) treatment stage for organic destruction. Future waste stream estimates have been shown to contain organic content requiring excess hydrogen peroxide addition. Restoration of the PDM will ensure the ETF can accommodate the higher anticipated levels of organic content in these new influent streams. Due to low organic content levels in the current influents and some operability issues with the PDM, it has not been in operation since 1998. One aspect of the repair and upgrade of the PDM is the usability of manganese dioxide on alumina catalyst, Sud-Chemie T-2525, which was purchased in 2008 but has remained in storage since. The manufacturer of the catalyst states there is no known shelf life for the product and no current data to indicate the catalyst's performance after long-term storage. To determine the usability of the stored catalyst, a laboratory test was developed. The testing of this stored catalyst was based on testing methods and information collected from initial catalyst product testing performed in 2008. This test involved spiking the catalyst with 200 ppm hydrogen peroxide and then testing the resulting solution to determine the extent of peroxide destruction. Initial testing results of the Sud-Chemie T-2525 catalyst indicated reduced performance, so additional catalyst materials were selected for inclusion in the testing. These materials included Carulite{sup R} 200 catalyst, LayneOx{sup R}, natural manganese ore - pyrolusite (Pro-Ox{sup R}), and EnviCat{sup R} 2531 SPH 4-6. With the expansion of the test scope, fines generation testing was added to provide additional data for product selection, as excessive fines cause plugging in the PDM. The resulting test data are compared to the 2008 catalyst product testing data in order to evaluate performance of each product to determine whether the Sud-Chemie T-2525 is still viable and to determine the best candidate for its replacement. This testing provides essential information to the engineering and operations organizations managing the facility and equipment upgrades for the ETF. (authors)

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DOE OSTI2020

Panel Session 23: Start-up of Three Major DOE Treatment Facilities - SWPF, IWTU and DFLAW

This panel focused on the DOE-EM planning to complete construction and start up three major treatment facilities in the next 18 months. This included the Salt Waste Processing Facility (SWPF) at Savannah River, the Integrated Waste treatment Unit (IWTU) at Idaho and the Direct Feed Low-Activity Waste (DFLAW) at Hanford. DOE Site Managers from SC, ID and WA introduced each facility then the DOE Contractor provided the details on their biggest challenges in regulatory issues, construction, start-up and operations of each facility. Panelists with presentations: Lessons in Managing Risks in First of a Kind Nuclear Construction and Start-Up (Pamela Marks); Integrated Waste Treatment Unit (Connie Flohr); IWTI-Fluor (Frederick Hughes); Startup and Commissioning (Tom Fletcher)

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