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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil

Highlights: > The effects of soil physical properties on gas transport parameters were investigated. > Higher values of D{sub p} and k{sub a} exhibited in the '+gravel' than the '-gravel' fraction at same soil-air content ({epsilon}). > Recent power law models for D{sub p} (WLR) and k{sub a} (RPL) were modified. > Model parameters were linearly related to easily measurable dry bulk density ({rho}{sub b}). - Abstract: Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, {rho}{sub b}, and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D{sub p}/D{sub o}, ratio of gas diffusion coefficients in soil and free air) and air permeability (k{sub a}) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting {rho}{sub b} values ranging from 1.40 to 2.10 g cm{sup -3}. Results showed that D{sub p} and k{sub a} values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2 mm) under variably-saturated conditions for a given soil-air content ({epsilon}), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D{sub p} and k{sub a} was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D{sub p}/D{sub f}, the ratio of measured D{sub p} to D{sub p} in total porosity (f), (ii) for air permeability k{sub a}/k{sub a,pF4.1}, the ratio of measured k{sub a} to k{sub a} at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content ({epsilon}) to total porosity (f) (air saturation). Based on the normalized parameters, predictive power-law models for D{sub p}({epsilon}/f) and k{sub a}({epsilon}/f) models were developed based on a single parameter (water blockage factor M for D{sub p} and P for k{sub a}). The water blockage factors, M and P, were found to be linearly correlated to {rho}{sub b} values, and the effects of dry bulk density on D{sub p} and k{sub a} for both '+gravel' and '-gravel' fractions were well accounted for by the new models.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Using the Diffusion Equation to Predict CST Resin Breakthroughs - 19051

The crystalline silicotitanate, CST, resin manufactured by UOP Honeywell is well-suited for single-use decontamination of caustic liquid wastes at Hanford and Savannah River Sites. There are many measurements of column loading and breakthrough for CST resin decontamination of Cs-137 in various Hanford and SRS waste simulants. Such measurements provide a very good basis for estimating CST resin demand and these more refined predictions make the CST column loading as efficient as possible given the very expensive CST resin. Although there are a variety of tools for predicting chromatographic resin column performance, [1-4], there is a particularly useful method that is suitable as a simple spreadsheet model [4]. This spreadsheet model is an analytical error function for the mass transfer zone (mtz) diffusion width in resin columns and is well-suited for resin breakthrough and column loading. This paper describes just such an error function spreadsheet model and how well the error function agrees with more traditional models and fits the observed small scale breakthrough curves for CST that can then better predict large scale column loading efficiency. The very high sorption of Cs onto CST tends to be slower than that of other lower sorption resins and as a result of the slow CST kinetics, there is also a marked asymmetry in many CST breakthrough curves. The CST breakthrough asymmetry is largely due to the distribution of CST particle sizes because smaller particles sorb much faster than larger particles. It is then the smaller particles that determine the leading mtz at a decontamination factor of 1,000 breakthrough and therefore the decontamination efficiency for a given loading. The larger CST particles correspondingly determine the tailing mtz width and therefore the overall loading efficiency and it is important to model both leading and tailing mtz widths to best optimize CST for a particular Cs-137 decontamination application. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

GDSA framework, a computational framework for complex modeling problems in radioactive waste management

This paper details a computational framework to produce automated, graphical workflows, and how this framework can be deployed to support complex modeling problems like those in nuclear engineering. Key benefits of the framework include: automating previously manual workflows; intuitive construction and communication of workflows through a graphical interface; and automated file transfer and handling for workflows deployed across heterogeneous computing resources. This paper demonstrates the framework's application to probabilistic post-closure performance assessment of systems for deep geologic disposal of nuclear waste. However, the framework is a general capability that can help users running a variety of computational studies.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Final Report: Modifications and Optimization of the Organic Rankine Cycle to Improve the Recovery of Waste Heat

This research and development (R&D) project exemplifies a shared public private commitment to advance the development of energy efficient industrial technologies that will reduce the U.S. dependence upon foreign oil, provide energy savings and reduce greenhouse gas emissions. The purpose of this project was to develop and demonstrate a Direct Evaporator for the Organic Rankine Cycle (ORC) for the conversion of waste heat from gas turbine exhaust to electricity. In conventional ORCs, the heat from the exhaust stream is transferred indirectly to a hydrocarbon based working fluid by means of an intermediate thermal oil loop. The Direct Evaporator accomplishes preheating, evaporation and superheating of the working fluid by a heat exchanger placed within the exhaust gas stream. Direct Evaporation is simpler and up to 15% less expensive than conventional ORCs, since the secondary oil loop and associated equipment can be eliminated. However, in the past, Direct Evaporation has been avoided due to technical challenges imposed by decomposition and flammability of the working fluid. The purpose of this project was to retire key risks and overcome the technical barriers to implementing an ORC with Direct Evaporation. R&D was conducted through a partnership between the Idaho National Laboratory (INL) and General Electric (GE) Global Research Center (GRC). The project consisted of four research tasks: (1) Detailed Design & Modeling of the ORC Direct Evaporator, (2) Design and Construction of Partial Prototype Direct Evaporator Test Facility, (3) Working Fluid Decomposition Chemical Analyses, and (4) Prototype Evaluation. Issues pertinent to the selection of an ORC working fluid, along with thermodynamic and design considerations of the direct evaporator, were identified. The FMEA (Failure modes and effects analysis) and HAZOP (Hazards and operability analysis) safety studies performed to mitigate risks are described, followed by a discussion of the flammability analysis of the direct evaporator. A testbed was constructed and the prototype demonstrated at the GE GRC Niskayuna facility.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Release Fractions from Airborne Fluid and Slurry Spills

Release fractions are commonly used to make conservative estimates of emissions from processes and are applied to characterize industrial operations to safeguard workers and public. Release fractions cannot be derived theoretically; they must be measured. Appropriate measurements are limited. This paper describes tests that were conducted to provide large-scale release fraction data for estimating releases from three operations proposed for waste remediation at the Hanford Site in Richland, Washington. Experiments were conducted to measure release fractions of three processes: 1) pipe discharge of liquid and slurry in free fall into a liquid or slurry, 2) jet transfer of contents to the other side of the tank either impacting the tank wall or falling into the fluid pool, and 3) high pressure fan jet striking a steel plate or simulated waste from a small stand-off distance. The tests were conducted without forced ventilation in an enclosed prototypic ¼-scale model of a 3785 m^3 (1 million gallon) tank in use at the Hanford Site for storage of radioactive waste. Aerosol releases were characterized based on filter samples of aerosol collected near the process stream, tank wall, and tank top to determine release fraction at engineering scale. Particle size distribution measurements were analyzed to determine whether the particles were in the respirable range. The release fractions for the top of the unventilated tank ranged from 9x10-7 to 6x10-4 depending on the process simulated. The particle size distribution was determined to be log-normally distributed with geometric mean diameters ranging from 3 to 8 µm. Thus, all particles are conservatively considered to be “respirable.”

aerosol generation, release fraction, water spill,↗
DOE OSTI2026

Volume Change from Solidification Correlation for Hanford Tank Waste.

The U.S. Department of Energy (DOE), Hanford Field Office’s primary mission is to safely and effectively treat Hanford’s tank waste and deliver environmental remediation. Mixed radioactive waste is stored in the underground tanks at the Hanford Site. It was recently estimated that retrieval of the waste in the 200 West Area underground tanks in the SY, S, SX, and U Tank Farms will result in about 41 million gallons of mixed low-level waste (MLLW) (RPP-RPT-65147, Rev. 1). The current plan is to retrieve at least 22 S, SX, and U Farm tanks and pretreat1 to produce pretreated tank waste (PTW) which will be further treated (including solidification /immobilization) for Resource Conservation and Recovery Act (RCRA) Land Disposal Restriction (LDR) organics and inorganics before being transferred to an offsite out-of-state facility for disposal (RPP-PLAN-66135, Rev. 2). In addition, solidified PTW from the 200 East Area may also be transferred to an offsite out-of-state facility for disposal to ensure availability of critical Double-Shell Tank space, meet retrieval obligations, and optimize 200 East Area operations.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Hanford Direct Feed Low Activity Waste Program Throughput Optimization Through Modeling - 18587

The Direct Feed Low Activity Waste (DFLAW) program at Hanford allows for the early treatment of tank wastes years earlier than previously planned. Operational Research (OR) modeling is being used to provide invaluable insight into how complex and integrated processes will operate. The DFLAW OR models are used to help optimize the design and operation of the integrated system. The DFLAW OR models include the processes and real-life complexities involved in the day-to-day operation of the systems and equipment, and can predict key performance characteristics including throughput, mission timescale, equipment and labor utilization, lag storage and capacity requirements. The DFLAW OR models also have the in-built capability to simulate random events such as equipment failures. Adding random variability to models introduces a real-life element to model results. For example, OR modeling breakdown analysis of equipment failure and restoration times may inform specific improvements to a design and plant operation, including areas where the provision of spare (duty/standby) equipment would prove beneficial; the optimum number and capacity of lag storage tanks (for waste intermediate storage, reagents, etc.); operational issues, including scheduling constraints, labor resource constraints, effect of shift schedules (e.g. days only, extended shifts, 24/7),, maintenance strategies, including planned maintenance, equipment upgrades, on-hand spare part stockholding, etc. At Hanford, standalone OR models to date, have been used to help identify key operational issues and improve the design and operation of individual systems within the Tank Farms, Low Activity Waste Pretreatment System (LAWPS), Low Activity Waste (LAW) Vitrification and Effluent Management Facility (EMF) and Integrated Disposal Facility (IDF), logistics and infrastructure, 222-S laboratory [References 1 and 2] including: - Identification of critical spares including transfer pumps; - Underpin size and number of lag storage tanks to maintain continuous LAW feed to the LAW melters; - Underpin sample turnaround times at the 222-S Laboratory (e.g. feed prequalification and evaporator campaign samples) and determine how targets can be achieved without impacting waste feed delivery to LAWPS and the LAW Vitrification Facility; - Determine operational strategy required at IDF including shift schedules and sizes and the number of ILAW transporters that can support DFLAW throughput; - Identification of lag storage management strategies for glass formers, reagents, other consumables due to delivery distance and delays due to bad weather; and - Truck delivery badging needs to support 24/7 operation and management of shift in/out times required to reduce congestion. An Integrated DFLAW OR model has been developed and combines the standalone OR models such that integrated throughput and availability can be assessed from a program perspective. The Integrated OR model will provide a more detailed understanding of the interactions between Tank Farms, LAWPS, LAW VIT and IDF such that key bottleneck areas can be identified and ensure improvements are focused. Examples of future improvements that may be considered include identification of critical spare parts, required on-site maintenance capabilities, shift scheduling, and craft and labor availability. The methods, results and insights derived by DFLAW OR modeling efforts are expected to provide useful applications to other projects that involve combinations of mechanical handling, chemical processing, waste treatment/packaging or environmental remediation operations. (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 OSTI2013

TRANSIENT HEAT TRANSFER ANALYSIS FOR SRS RADIOACTIVE TANK OPERATION

The primary objective of the present work is to perform a heat balance study for type-I waste tank to assess the impact of using submersible mixer pumps during waste removal. The temperature results calculated by the model will be used to evaluate the temperatures of the slurry waste under various tank operating conditions. A parametric approach was taken to develop a transient model for the heat balance study for type-I waste tanks such as Tank 11, during waste removal by SMP. The tank domain used in the present model consists of two SMP's for sludge mixing, one STP for the waste removal, cooling coil system with 36 coils, and purge gas system. The sludge waste contained in Tank 11 also has a decay heat load of about 43 W/m{sup 3} mainly due to the emission of radioactive gamma rays. All governing equations were established by an overall energy balance for the tank domain, and they were numerically solved. A transient heat balance model used single waste temperature model, which represents one temperature for the entire waste liquid domain contained in the tank at each transient time.

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DOE OSTI2020

Inspection Tools for Hanford Tanks and Waste Transport Systems - 20444

Recent integrity issues in the double-shell tanks (DST) at Hanford have motivated the need for developing innovative tools that can provide information regarding the health of the tanks. These issues include the primary linear failure of AY-102 and recent concerns of thinning in the DST secondary liners. Other concerns include erosion or corrosion on transfer lines and processing pipes. In recent years, Florida International University (FIU) has supported DOE-EM by developing tools that can assist in understanding the health of tanks and waste transport system at Hanford. More specifically, FIU has developed a miniature rover that can be deployed through small risers and gain access to refractory slots in the Hanford DSTs. It traverses through the slots on the primary liner upside down via magnets to avoid debris in the slots. Recent modifications include a spring loaded magnetic arm that allows the unit to traverse over large weld seams but does not reduce the overall functionality of the system. The system has also incorporated a control capsule that will sit within the annulus of the tank and improves on issues related to signal and voltage loss over long tether lines. Lastly, the unit is also being augmented with a second module that will include a means to prep the tank surface and obtain a thickness measurement using a dual element ultrasonic sensor. FIU has also developed a 6-inch peristaltic pipe crawler that operates similar to the previous pipe crawlers developed at FIU. This crawler is a marsupial type crawler that will navigate through the 6-inch drain lines, and deploy a small rover at the entrance of the drain slots. This rover will also traverse upside down on the secondary liner and provide information regarding the health of the liner. An initial prototype for the crawler unit has been developed, assembled and tested. The system is pneumatic and consists of three modules - two grippers and one extender. The validation tests are conducted in a mockup of the drain lines and demonstrate the system's ability to navigate through long pipe lengths and elbows. In this paper, a general overview of each of the aforementioned systems is presented along with results from testing and demonstrations that shows the applicability of each system. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Analysis Of The Sludge Batch 7b (Macrobatch 9) DWPF Pour Stream Glass Sample (Rev. 1)

The Defense Waste Processing Facility (DWPF) began processing Sludge Batch 7b (SB7b), also referred to as Macrobatch 9 (MB9), in January 2012. SB7b is a blend of the heel of Tank 40 from Sludge Batch 7a (SB7a) and the SB7b material that was transferred to Tank 40 from Tank 51. SB7b was processed using Frit 418. During processing of each sludge batch, the DWPF is required to take at least one glass sample to meet the objectives of the Glass Product Control Program (GPCP), which is governed by the DWPF Waste Form Compliance Plan, and to complete the necessary Production Records so that the final glass product may be disposed of at a Federal Repository. Two pour stream glass samples were collected while processing SB7b. The samples were transferred to the Savannah River National Laboratory (SRNL) where one was analyzed and the other was archived. The following conclusions were drawn from the analytical results provided in this report: The sum of oxides for the official SB7b pour stream glass is within the Product Composition Control System (PCCS) limits (95-105 wt%); The average calculated Waste Dilution Factor (WDF) for SB7b is 2.3. In general, the measured radionuclide content of the official SB7b pour stream glass is in good agreement with the calculated values from the Tank 40 dried sludge results from the SB7b Waste Acceptance Program Specification (WAPS) sample; As in previous pour stream samples, ruthenium and rhodium inclusions were detected by Scanning Electron Microscopy-Electron Dispersive Spectroscopy (SEM-EDS) in the SB7b pour stream sample; The Product Consistency Test (PCT) results indicate that the official SB7b pour stream glass meets the waste acceptance criteria for durability with a normalized boron release of 0.8 g/L, which is an order of magnitude less than the Environmental Assessment (EA) glass; The measured density of the SB7b pour stream glass was 2.70 g/cm 3 ; The Fe 2+ /ΣFe ratio of the SB7b pour stream samples was 0.07.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Sorption Modeling and Verification for Off-Gas Treatment

This project was successfully executed to provide valuable adsorption data and improve a comprehensive model developed in previous work by the authors. Data obtained were used in an integrated computer program to predict the behavior of adsorption columns. The model is supported by experimental data and has been shown to predict capture of off gas similar to that evolving during the reprocessing of nuclear waste. The computer program structure contains (a) equilibrium models of off-gases with the adsorbate; (b) mass-transfer models to describe off-gas mass transfer to a particle, diffusion through the pores of the particle, and adsorption on the active sites of the particle; and (c) incorporation of these models into fixed bed adsorption modeling, which includes advection through the bed. These models are being connected with the MOOSE (Multiphysics Object-Oriented Simulation Environment) software developed at the Idaho National Laboratory through DGOSPREY (Discontinuous Galerkin Off-gas SeParation and REcoverY) computer codes developed in this project. Experiments for iodine and water adsorption have been conducted on reduced silver mordenite (Ag0Z) for single layered particles. Adsorption apparatuses have been constructed to execute these experiments over a useful range of conditions for temperatures ranging from ambient to 250°C and water dew points ranging from -69 to 19°C. Experimental results were analyzed to determine mass transfer and diffusion of these gases into the particles and to determine which models best describe the single and binary component mass transfer and diffusion processes. The experimental results were also used to demonstrate the capabilities of the comprehensive models developed to predict single-particle adsorption and transients of the adsorption-desorption processes in fixed beds. Models for adsorption and mass transfer have been developed to mathematically describe adsorption kinetics and transport via diffusion and advection processes. These models were built on a numerical framework for solving conservation law problems in one-dimensional geometries such as spheres, cylinders, and lines. Coupled with the framework are specific models for adsorption in commercial adsorbents, such as zeolites and mordenites. Utilizing this modeling approach, the authors were able to accurately describe and predict adsorption kinetic data obtained from experiments at a variety of different temperatures and gas phase concentrations. A demonstration of how these models, and framework, can be used to simulate adsorption in fixed- bed columns is provided. The CO 2 absorption work involved modeling with supportive experimental information. A dynamic model was developed to simulate CO 2 absorption using high alkaline content water solutions. The model is based upon transient mass and energy balances for chemical species commonly present in CO 2 absorption. A computer code was developed to implement CO 2 absorption with a chemical reaction model. Experiments were conducted in a laboratory scale column to determine the model parameters. The influence of geometric parameters and operating variables on CO 2 absorption was studied over a wide range of conditions. Continuing work could employ the model to control column operation and predict the absorption behavior under various input conditions and other prescribed experimental perturbations. The value of the validated models and numerical frameworks developed in this project is that they can be used to predict the sorption behavior of off-gas evolved during the reprocessing of nuclear waste and thus reduce the cost of the experiments. They can also be used to design sorption processes based on concentration limits and flow-rates determined at the plant level.

42 ENGINEERING↗
DOE OSTI2016

Final Scientific Report: Bacterial Nanowires and Extracellular Electron Transfer to Heavy Metals and Radionuclides by Bacterial Isolates from DOE Field Research Centers

This proposal involved the study of bacteria capable of transferring electrons from the bacterial cells to electron acceptors located outside the cell. These could be either insoluble minerals that were transformed into soluble products upon the addition of electrons, or they could be soluble salts like uranium or chromium, that become insoluble upon the addition of electrons. This process is called extracellular electron transport or EET, and can be done directly by cellular contact, or via conductive appendages called bacterial nanowires. In this work we examined a number of different bacteria for their ability to perform EET, and also looked at their ability to produce conductive nanowires that can be used for EET at a distance away from the EET-capable cells. In the work, new bacteria were isolated, new abilities of EET were examined, and many new methods were developed, and carefully described in the literature. These studies set the stage for future work dealing with the bioremediation of toxic metals like uranium and chromium. They also point out that EET (and conductive nanowires) are far more common that had been appreciated, and may be involved with energy transfer not only in sediments, but in symbioses between different bacteria, and in symbiosis/pathogenesis between bacteria and higher organisms.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Materials-to-device design of hybrid metal-polymer heat exchanger tubes for low temperature waste heat recovery

Heat exchangers for low temperature (<150 °C) waste heat recovery (WHR) are challenging due to severe constraints on materials costs, manufacturing methods, and maintenance opportunities after installation. Here, the use of polymers instead of metals, offers an avenue for cost reduction in WHR applications, provided the typical low thermal conductivity of polymers (~0.2 W m –1 K –1 ) that results in poor overall heat transfer coefficient can be overcome. Previous approaches to enhance the thermal conductivity of polymers remain problematic in terms of cost, thermal, and thermomechanical considerations. In this work, we propose a novel hybrid metal-polymer composite assembled from strips of polymer and copper. Polymer strips with metal-clad edges are wound helically and the interfaces between the strips joined to obtain a tube for a cross-flow heat exchanger. Interfaces are designed to enhance effective heat conduction across the material and increase the overall heat transfer coefficient. Through numerical simulations, we obtain metal-polymer layouts that achieve wall effective thermal conductivity ~1 W m –1 K –1 at ~23% or ~35% volume fraction of copper or aluminum, respectively. The conductivity enhancement is sufficient for typical low temperature WHR, resulting in a ~20% enhancement in the overall heat transfer coefficient compared to a similar all-polymer heat exchanger. Thermomechanical simulations revealed that the composite pipe designs can withstand >1.4 MPa internal pressure, under the normal operating conditions of the heat exchanger. Our work provides guidelines for designing macroscopic metal-polymer composites that can be adapted for specific requirements such as reduced materials costs, ease of manufacturing, and heat transfer enhancement. In conclusion, the optimized design of hybrid metal-polymer heat exchanger tubes potentially provides a scalable and cost-effective route toward harvesting waste heat from low temperature sources.

42 ENGINEERING↗
DOE OSTI2012

Analysis Of DWPF Sludge Batch 7a (Macrobatch 8) Pour Stream Samples

The Defense Waste Processing Facility (DWPF) began processing Sludge Batch 7a (SB7a), also referred to as Macrobatch 8 (MB8), in June 2011. SB7a is a blend of the heel of Tank 40 from Sludge Batch 6 (SB6) and the SB7a material that was transferred to Tank 40 from Tank 51. SB7a was processed using Frit 418. During processing of each sludge batch, the DWPF is required to take at least one glass sample to meet the objectives of the Glass Product Control Program (GPCP), which is governed by the DWPF Waste Compliance Plan, and to complete the necessary Production Records so that the final glass product may be disposed of at a Federal Repository. Three pour stream glass samples and two Melter Feed Tank (MFT) slurry samples were collected while processing SB7a. These additional samples were taken during SB7a to understand the impact of antifoam and the melter bubblers on glass redox chemistry. The samples were transferred to the Savannah River National Laboratory (SRNL) where they were analyzed.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Dry Storage of Research Reactor Spent Nuclear Fuel - 13321

Spent fuel from domestic and foreign research reactors is received and stored at the Savannah River Site's L Area Material Storage (L Basin) Facility. This DOE-owned fuel consists primarily of highly enriched uranium in metal, oxide or silicide form with aluminum cladding. Upon receipt, the fuel is unloaded and transferred to basin storage awaiting final disposition. Disposition alternatives include processing via the site's H Canyon facility for uranium recovery, or packaging and shipment of the spent fuel to a waste repository. A program has been developed to provide a phased approach for dry storage of the L Basin fuel. The initial phase of the dry storage program will demonstrate loading, drying, and storage of fuel in twelve instrumented canisters to assess fuel performance. After closure, the loaded canisters are transferred to pad-mounted concrete overpacks, similar to those used for dry storage of commercial fuel. Unlike commercial spent fuel, however, the DOE fuel has high enrichment, very low to high burnup, and low decay heat. The aluminum cladding presents unique challenges due to the presence of an oxide layer that forms on the cladding surface, and corrosion degradation resulting from prolonged wet storage. The removal of free and bound water is essential to the prevention of fuel corrosion and radiolytic generation of hydrogen. The demonstration will validate models predicting pressure, temperature, gas generation, and corrosion performance, provide an engineering scale demonstration of fuel handling, drying, leak testing, and canister backfill operations, and establish 'road-ready' storage of fuel that is suitable for offsite repository shipment or retrievable for onsite processing. Implementation of the Phase I demonstration can be completed within three years. Phases II and III, leading to the de-inventory of L Basin, would require an additional 750 canisters and 6-12 years to complete. Transfer of the fuel from basin storage to dry storage requires integration with current facility operations, and selection of equipment that will allow safe operation within the constraints of existing facility conditions. Examples of such constraints that are evaluated and addressed by the dry storage program include limited basin depth, varying fuel lengths up to 4 m, (13 ft), fissile loading limits, canister closure design, post-load drying and closure of the canisters, instrument selection and installation, and movement of the canisters to storage casks. The initial pilot phase restricts the fuels to shorter length fuels that can be loaded to the canister directly underwater; subsequent phases will require use of a shielded transfer system. Removal of the canister from the basin, followed by drying, inerting, closure of the canister, and transfer of the canister to the storage cask are completed with remotely operated equipment and appropriate shielding to reduce personnel radiation exposure. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Thermal dissipation studies and Pu238/Li source simulation (MCNP) of the K2 containers (COWS)

The six K2 containers (COWS) have been proposed to be shipped to WIPP in the configuration depicted in Figure 1. Currently, the containers reside in the water bath storage and have not been opened since LANL received them. The K2 containers containing the mound scrap material each have their own unique dose rate and thermal loading. 3 The properties of each container are listed below in Table 1. The problem with loading the K2 container into the proposed configuration is the thermal load the package will experience. Each component within the package has a thermal working limit that should not be exceeded. 2 However, the package must also maintain enough shielding to lower the measured dose rate at the surface of the drum to be accepted by WIPP. Testing the current configuration through simulation LANL can prove heat will not compromise any components and dose can be reduced to a safe configuration.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Characterization of infrequent samples from the concentration, storage and transfer facility: leak detection box (LDB) drain cell sample LIMS# 20195

Savannah River Remediation Engineering (SRR-E) requested that the Savannah River National Laboratory (SRNL) analyze the Concentration, Storage, and Transfer Facility (CSTF) samples from the following Tank Farm areas: the sump encasement, catch tank, drain cell and waste tank annulus. In general, these CSTF samples will be analyzed on an infrequent basis and analyses will include detection for total beta/gamma, total alpha activities and pH measurements. This report presents characterization results for the Leak Detection Box Drain Cell (LDB-DC) sample. The results are measurements for total gamma, total alpha, total beta, pH, density, anions, elementals and total mercury for the LDB-DC sample.

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