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Dense hydrogen layers for high performance MagLIF

We report that Magnetized Liner Inertial Fusion (MagLIF) experiments driven by the Z machine produce >10 13 deuterium-deuterium fusion reactions. Simulations indicate high yields and gains (1000) with increased current and deuterium-tritium layers for burn propagation. Such a coating also isolates the metal liner from the gaseous fuel, which should reduce mixing of liner material into the fuel. However, the vapor density at the triple point is only 0.3 kg/m3, which is not high enough for MagLIF operation. We present two solutions to this problem. First, a fuel wetted low-density plastic foam can be used to form a layer on the inside of the liner. The desired vapor density can be obtained by controlling the temperature. This does however introduce carbon into the layer which will enhance radiation losses. Simulations indicate that this wetted foam layer can significantly contribute to the fusion yield when the foam density is less than 35 kg/m 3 . Second, we show that a pure frozen fuel layer can first be formed on the inside of the liner and then low temperature gaseous fuel can be introduced just before the implosion without melting a significant amount of the ice layer. This approach is the most promising for MagLIF to produce high yield and gain.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Design of experiments to spectroscopically characterize radiation flow in stochastic media

Precise characterization of experimental radiation flow is required to validate the high energy density physics models, numerical methods, and codes that are used to simulate radiation-hydrodynamics phenomena such as thermal radiation transport in stochastic media. The Cassio code is used to simulate thermal radiation flow through inhomogeneous, stochastic-media-foam configurations containing optically thick clumps dispersed within an optically thin background aerogel. Cassio can model small inhomogeneous problems directly, but most problems require approximations to meet computer limitations on run-times and memory usage. Various examples of these approximations are methods that produce, in one calculation, an ensemble-averaged solution and associated standard deviation; reduced spatial dimensionality with approximate geometries; and full material homogenization with no geometric detail. Cassio simulations are used to design experiments at the OMEGA-60 Laser Facility that can measure the radiation flow using the spatially resolved COAX absorption spectroscopy diagnostic. The experimental platforms flow radiation through foam targets ranging from a background-only aerogel, to a single configuration of a specified stochastic medium, to a fully homogenized foam of the background and clump materials. Under constant total clump mass, larger clumps (here, larger than 10 μm diameter) will mix more slowly with the background such that the bulk radiation flow is faster than it would be in a fully homogenized material. The COAX platform can be used to infer temperature and density profiles in both the background material and clumps, simultaneously, and therefore to differentiate radiation flow in a range of stochastic and homogeneous media.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Three-dimensional particle-in-cell simulations of laser-driven multiradiation sources based on double-layer targets

Double-layer targets (DLTs), made of a low-density foam on top of a solid substrate, can efficiently convert the energy of a high-intensity laser to provide sources of photons and protons. We investigate a 30-fs pulse with a peak intensity of I ~ 8.7×10 20 W/cm 2 and a peak power of ~120 TW interacting with a DLT using three-dimensional (3D) particle-in-cell simulations. We focus on providing quantitative results in full 3D geometry on the foam thickness dependence; on the competition between two photon-generating processes in DLTs, i.e., nonlinear inverse Compton scattering (NICS) and bremsstrahlung (BS); and on the acceleration of protons via enhanced target-normal sheath acceleration. Here, we discuss conversion efficiency, average energy, and angular distributions of such multiradiation sources. We find that NICS can prevail over BS if the DLT's substrate is thin enough (~µ⁢m) and that the optimal foam thickness that maximizes the conversion efficiency in NICS and BS photons and the proton cutoff energy, among those considered, is the same (15µ⁢m). These results show that DLTs constitute an excellent tool for developing relatively compact and optimized laser-driven multicomponent radiation sources.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Effect of sucrose on technetium and rhenium retention during vitrification of low-activity wastes

Sucrose (C 12 H 22 O 11 ) has been used in low-activity waste (LAW) melter feeds containing large fractions of nitrates, nitrites, or both because it facilitates foam suppression and denitration. This study focused on the effect of sucrose in LAW feeds on technetium (Tc) and rhenium (Re) retention. The amount of sucrose added in feeds was varied to differentiate the carbon-to-nitrogen mole ratio (C/N ratio). The results show that larger sucrose addition (higher C/N ratio) enhances Tc and Re retention. Reducing conditions induced by sucrose decomposition and early chemical reactions between sucrose and NaNO 3 /NaNO 2 are expected to increase Tc and Re retention. However, high sucrose addition decreased sulfur (S) retention slightly because sodium sulfate decomposes in reducing conditions at lower temperature. This early sulfate decomposition can affect Tc and Re retention partly because these species can be soluble in sulfate phases. This correlation indicates that the decrease of sulfate phases in the glass by early decomposition can reduce the solubility of Tc and Re in the sulfate phases, which may increase Tc and Re retention in the glass. In addition, continuous gas evolution and vigorous foaming at the foaming temperature range of 700–900°C may influence Tc and Re retention process interrupting retention or facilitating volatilization.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Functional Photoresists for Energy Applications. Final Report

Monolithic ultralow-density porous bulk materials have recently attracted much interest due to many emerging applications in the areas of catalysis, energy storage and conversion, and thermal insulation. They are also important components of high energy density (HED) and inertial confinement fusion (ICF) targets. However, despite tremendous progress that has been made in the synthesis of porous materials, deterministic and independent control over microscopic architecture, density and composition remain key issues, and their integration in high precision devices requires cost and time-intensive mechanical machining that not only reduces reproducibility by generating debris but also limits the complexity of the 3D shapes that can be realized. In this project, we overcame these limitations by developing a universal templating capability that provides deterministic and independent control over density, composition, architecture, and macroscopic sample shape. This was achieved by developing the technology to 1) 3D print ultrahigh resolution, ultra-high precision polymeric micro-lattice templates, 2) coat these templates with the desired materials, and 3) removing the template (Fig. 1a). Atomic layer deposition (ALD) provides the atomic scale coating thickness accuracy required for precisely controlling density. While this templating approach had been demonstrated in prior work, limitations in suitable photoresists, 3D print technologies, print design, and template removal techniques did not allow the fabrication of millimeter-sized high-precision parts with sub-micron resolution. To enable this technology, we developed 1) two-photon polymerization (TPP) print designs that enable the fabrication of millimeter-sized, mechanically robust polymeric templates with sub-micron resolution and 2) a continuum level TPP printing simulation capability for additional print design guidance; 3) atomistic models to study photoresist polymerization kinetics and network topography, 4) refractive index matched polymeric and preceramic TPP photoresists, and 5) functional TPP photoresists including porous voxel structures and self-immolative polymer photoresist chemistries; and 6) damage free template removal techniques that enable the fabrication of defect-free high-precision low-density foam components. We also developed a templating approach for pure carbon microlattices with a unique tube-in-tube ligament morphology. As a test platform, we pursued the fabrication of foam liners that promise to further increase the neutron yield in indirect drive ICF experiments by improving implosion symmetry control and coupling between the laser and the deuterium-tritium fuel. This application requires fabrication and integration of a ultra-high precision, millimeter-sized, thin-walled (200-400 micrometer thick), low-density (10-30 mg/cc), high atomic number (high Z) cylindrical foam tube into the gold hohlraum of an indirect drive ICF target (Fig. 1b). While our hohlraum liner test case will mainly find application in HED and ICF experiments, the underlying science will also directly apply to previously developed nanoparticle and additive manufacturing technologies and will advance those techniques as well.

36 MATERIALS SCIENCE↗

Preshot Report for the NIF DDCyl Campaign: H_Hyd_DDCyl_DRT_AAA/BBB/CCC

The first two cylinder shot days on the National Ignition Facility, allocated through the Discovery Science program, provided a successful demonstration of the cylinder platform on the NIF. Both of these shot days used cylinders that were nominally 3 times larger in radial dimension than cylinders fielded at the OMEGA laser facility, here referred to as scale-3 targets. In the first Discovery Science shot day, we demonstrated that Rayleigh-Taylor instability growth during the deceleration phase is scale-invariant between the scale-1 OMEGA experiments and similarly tailored scale-3 NIF experiments at the same convergence ratio of CR=initial radius/final radius=2.25. In the second Discovery Science shot day, we increased the convergence ratio by lowering the density of the central foam from 300 mg/cm 3 to roughly 40 mg/cm 3 with the same laser drive, resulting in a higher CR=5 at the time when the rebounding shock strikes the aluminum marker. We also greatly improved the imaging setup for the second shot day, resulting in much higher quality (greater signal-to-noise) radiographs of the implosion. This current shot day was awarded through the High Energy Density (HED) Council, following this demonstration of platform viability. It was originally scheduled for June 2020, but it was postponed several times due to the COVID-19 pandemic. It is currently scheduled for January 6, 2021. For this shot day, we will increase the radial dimension of the cylinder to four times the OMEGA-scale targets, and these will be referred to as scale-4 cylinders. Increasing the radial dimension of the target is advantageous as we push these targets to higher convergence ratio. By starting with an initially larger target, the target can push to a higher CR while maintaining the same final viewing area. Other than the larger radial dimension, the targets are very similar in design to the previous ones, consisting of an epoxy ablator, an embedded aluminum marker layer, and a low density central CH foam. These will also use a 40 mg/cm3 CH foam, reaching a CR~4.5 with the same laser energy (the added target mass reduces the final CR slightly). Note that this is NOT designed to be scale-invariant with the previous scale-1 OMEGA and scale-3 NIF shots. It was determined that the laser energy required to achieve a scale-invariant implosion was above the allowable optics damage limits (though achievable on the NIF) for these scale-4 targets.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Imaging APO-BMI with Micro X-ray Computed Tomography (CT)

APO-BMI is a high-strength, high-temperature, and low-density foam comprised of 1,2-bis(2-aminophenylthio) ethane (APO-Link, formerly Apocure-601) and 4,4’-bismaleimidodiphenylmethane (BMI) that is used structural applications within the aerospace and weapons manufacturing sectors. APO-link is the diamine reagent used to synthesize BMI, a thermosetting resin. This resin can remain in a molten, flowing state for an extended period of time before crosslinking, allowing addition of glass or carbon microballoons to form its final structure. A portion of the current project was to observe the thermal effects on the structural integrity of the foam associated with exposure to an ion beam. Features within the foam were imaged using micro X-ray computed tomography (CT). The resulting imaging provided evidence that microballoon structure remained mostly intact at the points of failure, indicating that the failure of the material was occurring in the binder material.

36 MATERIALS SCIENCE↗

Integrated Heat Exchanger-Phase Change Material Thermal Energy Storage System

The purpose of this study is to experimentally investigate the thermal performance of an innovative thermal energy storage (TES) system that combines the advantages of the phase-change material (PCM)/graphite foam latent heat TES medium developed at Argonne National Laboratory (Argonne) and the internally supported plate-fin (ISPE) cell architecture heat transfer fluid (HTF) flow channels developed at Brayton Energy (Brayton). Several essential tasks were accomplished: (1) Thermal property characterization. Thermal properties of the graphite foam were characterized, providing necessary data for experimental result analysis and numerical simulation. (2) Design and optimization of lab-scale test module. Based on Brayton’s full-scale heat exchanger (HX)-TES system, the experimental test module was designed, optimized, and fabricated. (3) Thermal performance testing and data analysis. Five cycle tests were successfully conducted—including one with approximately 3.5 psig of pressure applied to the diaphragms—to investigate the thermal performance of the experimental test module for charging and discharging. Temperature profiles were generated for each charging test and discharging test as a function of time. The temperature profiles clearly show three TES stages: sensible heat (temperature increase), latent heat (melting), and sensible heat (temperature increase) for the charging process. Similarly, the temperature profiles clearly show three thermal energy release stages: sensible heat (temperature decrease), latent heat (solidification), and sensible heat (temperature decrease). Melting and solidification of the PCM generally occurred in relatively narrow temperature ranges, indicated by the flattened temperature regions in the temperature profiles. These phase changes ranged approximately 3°C for melting and 3.5°C for solidification. The charging and discharging temperature profiles were similar for similar experimental parameter tests whether or not pressure was applied to the diaphragm to eliminate the gap between the HX surface and the TES subsystem. This indicates that the effect of a small gap between the HX surface and the TES subsystem is insignificant for charging and discharging. (4) Comparison of experimental data and simulation results. We compared the experimental data to the numerical simulation results. Numerical simulations were conducted by using the ANSYS FLUENT 2019 R3 commercial computational fluid dynamics software. The predicted phase-change times agreed reasonably well with those from the experimental data. In most cases, the estimated time differences between the relative phase changes were within 16%. The predicted start and end times for the charging process agreed well with those from the experimental data. However, the simulation results showed earlier start and end times than the experimental data for the discharging process. Overall, the experimental data and its comparison with the simulation predictions verified the technical viability of the integrated ISPF HX-PCM/graphite foam latent-heat TES system.

25 ENERGY STORAGE↗

Multiphysics and Multiscale Simulation Methods for Electromagnetic Energy Assisted Fossil Fuel to Hydrogen Conversion (Final Scientific/Technical Report)

This report summarizes the technical accomplishments of the four-year research project “Multiphysics and Multiscale Simulation Methods for Electromagnetic Energy Assisted Fossil Fuel to Hydrogen Conversion” (Award No. DE-FE0032092), conducted at Howard University and the University of Houston (subawardee) from September 2021 to August 2025. The project successfully achieved all four major objectives: 1. 3D Structural Characterization – Developed 3D optical imaging and mechanical sectioning methods to characterize catalyst distribution and support morphology in nickel foam substrates. Successfully reconstructed 3D geometries and imported them into COMSOL Multiphysics for electromagnetic simulations. 2. EM Hotspot Simulation – Created all-frequency stable electromagnetic formulations and 3D nodal discontinuous Galerkin (NDG) methods for coupled electromagnetic-thermal-fluid problems in multiscale catalytic media. Demonstrated stable solutions from DC to microwave frequencies. 3. Multiphysics Coupling – Developed multiscale simulation methods coupling FEM electromagnetic solvers with thermal transport equations. Reactive molecular dynamics (ReaxFF MD) simulations were performed to investigate catalytic reaction mechanisms at the atomistic level. Demonstrated electromagnetic-thermal co-simulation capabilities for porous catalyst structures. 4. System Optimization – Designed and optimized EM-assisted catalytic systems using nickel foam and carbon foam structures, demonstrating significant temperature increases due to microwave heating. Observed and characterized plasma generation in carbon fiber catalysts. Investigated multiple reaction chamber geometries for improved microwave energy deposition. The project produced significant scientific contributions including 15+ peer-reviewed publications, trained multiple Ph.D. students and undergraduate researchers, and advanced the understanding of microwave-assisted hydrogen production from fossil fuels.

08 HYDROGEN↗

Comparing Synthetic Routes and Thermal Characteristics of Alternate APO Variants

Low density, high-strength, temperature-resistant foams see widespread application in the aerospace and weapons fields due to their excellent qualities as structural supports. In these demanding environments, the most common formulation is a three-phase syntactic foam containing APOCure-601, BMI, and carbon or glass microballoons. Of these, APOCure-601 and BMI form the polymer resin amino-poly(oxadiazole) bismaleimide (APO-BMI), also known as Legacy APO or S-1,2-Ethyl-APO. In manufacturing this foam, the selective laser sintering (SLS) additive manufacturing technique is quickly gaining prominence, over more traditional injection molding since SLS allows for 3D printing of materials and reduces overall cost and waste production. That said, SLS also requires a narrow window between the melt and cure temperatures for a successful print. SLS printing of APO-BMI is therefore difficult since the compound possesses a broad window between its melting and curing temperatures, and also requires several post-cure steps or complete polymerization. This work explores synthesis optimization and thermal characteristics for variant Apo-BMI structures by observing the effect that alternative heteroatoms in the APO linkages, geometries 0f the BMI groups, and bridge structure identities impart on the resultant material. Synthetic methods for these altered structures were established in batch, with some others further converted to continuous flow chemistry, a method that produces materials in a continuous stream and is highly reproducible and readily scaled. Additionally, each structural change significantly altered the melt and cure properties for each APO variant, which is advantageous for SLS manufacturing.

60 APPLIED LIFE SCIENCES↗

Enhanced Pool Boiling of Low-Pressure Refrigerants on Round Tubes- An Experimental Evaluation

Pool boiling heat transfer is one of the most effective heat transfer methos and crucial for several energy conversion processes such as electronic cooling, steam generation, water purification and thermal management. Enhancing boiling heat transfer around the tubes enables higher heat flux, which can improve the efficiency and lead to compact heat exchangers. Delaying the onset of critical heat flux (CHF) allows for higher CHFs and protects equipment during anomalous transient conditions. Growing interest in process intensification and delayed CHF has motivated the current study. An experimental approach has been deployed to investigate a potential technique to enhance the pool boiling performance around small diameter tubes by open cell metal foams. The findings for nucleate pool boiling of Novec HFE 7000 on the externally enhanced and smooth tubes are reported. The enhanced tube comprised of compressed aluminum foam brazed around. All the samples were horizontally oriented, and the experiments were performed under ambient pressure conditions. The heat transfer measurements for the smooth tubes were compared with several existing correlations and established the baseline. The preliminary results showed that the aluminum foam effectively enhanced the heat transfer coefficient and delayed the onset of critical heat flux. In addition, the pool boiling process around the round tube sample was visualized from both side and front views to comprehend the heat transfer mechanisms underlying substantial enhancement observed during experiments.

Yang, Cheng-Min↗

THE DESIGN OF RADIAL HONEYCOMB LATTICES FOR IMPACT ENERGY ABSORPTION IN RADIOACTIVE MATERIALS PACKAGES

In this research we present a variation on the corrugation technique of honeycomb lattices, for cylindrical honeycombs, making them much easier to design for impact energy absorption in radioactive materials packages. This variation, termed radial honeycomb lattices, eliminates the residual strain and saddle effect. The use of honeycomb lattices provides advantages over the typically used foams. While foams are effective at absorbing impact energy, they can burn, their material properties are difficult to control, they can degrade over time, and procurement of raw materials can be dependent on timing of manufacturer batch runs. While the weaknesses of foam are strengths for honeycomb lattices, lattices have a different set of problems. Typically, when cylindrical honeycomb lattices are manufactured, they are manufactured flat, wrapped around a mandrel of the desired radius, and then brazed. This approach introduces residual strains, resulting in the saddle effect, which limits both the radial thickness and cylinder length. The radial honeycomb lattice approach presented here makes the design of thicker and longer cylinder honeycombs possible. To address these issues, we propose a honeycomb lattice which changes in cross-section from the inner to the outer radius of the cylinder. This causes the lattice to automatically wrap into a cylinder as it exits the corrugating gears. The theoretically bounding case, of a square cross-section at the inner radius, transitioning through a hexagon, to a diamond cross-section at the outer radius, results in a maximum thickness of approximately 41% of the inner radius. Full mathematical derivations, implemented in computer code, allow for the design of an entire radial honeycomb lattice, including the corrugating gears. To accomplish this only the radial thickness, inner cross-section shape, cell size, and nominal gear radius need to be specified, making the design of these lattices very efficient. Radial honeycomb lattice prototypes have demonstrated that the honeycomb does indeed wrap into a cylinder as intended, without the saddle effect, and can therefore be used to create thick-walled cylinders of any length. These design improvements make cylindrical honeycomb lattices much more accessible as a design element for radioactive materials packages

Johnson, William R. [Savannah River National Labor↗

Distinct Melt Infusion Architectures of Antiperovskite Solid Electrolytes

Antiperovskite solid electrolytes are an emerging class of lithium‐ion conductors distinguished by their unusually low melting points, enabling scalable, low‐temperature processing routes not accessible to most solid electrolytes. In this work, we synthesize phase‐pure chloride (Cl), bromide (Br), and mixed halide (ClBr) variants of antiperovskites and investigate their ionic conductivities in both powder and hot‐pressed forms. Hot pressing significantly enhances conductivity across all compositions, while energy‐dispersive X‐ray spectroscopy (EDS) of the mixed halide system reveals halide surface migration during densification. We further investigate the melt‐infiltration behavior of these electrolytes into substrates relevant to solid‐state battery architectures, including Al and Cu current collectors, conventional NMC and LFP cathodes, and a foamed NMC cathode with a highly porous architecture. The foamed cathode enables deep and uniform electrolyte penetration, highlighting the role of electrode architecture in facilitating melt infiltration. Across all substrates, electrolyte halide chemistry strongly influences wetting behavior, penetration depth, and resulting microstructural morphology. Together, these results establish clear processing–structure relationships for melt‐infiltrated antiperovskite solid electrolytes and demonstrate how electrolyte chemistry and electrode architecture govern interfacial morphology during integration, providing practical guidelines for processing and structural design in solid‐state battery systems.

antiperovskite↗

Critical roles of pores and moisture in sustainable nanocellulose-based super-thermal insulators

In a recent report in Matter, Bergström and co-workers describe a novel thermal transport behavior that subverts this assumption of porous materials. In their work, the authors describe a nanocellulose-based foam that features ultrahigh porosity (> 99.6%) and aligned µm-scale pores (10–100 µm) whose radial thermal conductivity (i.e., perpendicular to the pore alignment) is close to that of free air in the dry state. Furthermore, the radial thermal conductivity of the cellulose-based foam can be reduced to ~14 mW/(m·K) when the relative humidity is ~35%. Super-thermal insulators, which demonstrate a thermal conductivity below that of stationary air (~ 25 mW/(m·K), 20 ºC, 1.0 atm), are needed to minimize heat loss in various applications (e.g., buildings, thermal energy storage tanks, cold chain packaging, etc.) to mitigate the energy crisis and reduce carbon emissions. Introducing pores into a material is a facile and effective way to achieve low thermal conductivity as pores can suppress thermal transport through solids by reducing the cross-sectional area and increasing the tortuosity of the heat transfer pathway. In porous structures there are two kinds of pores: open and closed. While increased porosity can reduce heat conduction through solids with an open porous structure, the improved gas conduction creates a competing effect that simultaneously elevates the heat transfer. Therefore, the thermal conductivity of a material with µm-scale open pores is usually larger than that of stationary air. Reducing the pore size to less than the mean free path of air (~ 70 nm, 20 ºC, 1.0 atm) can effectively reduce gas conduction, enabling the material to achieve a thermal conductivity below that of stationary air. However, high cost of the nanosized raw materials and time-consuming fabrication processes limit the large-scale applications of nanoporous thermal insulators. Meanwhile, closed pores can block heat transport only through the continuous gas phase. As a result, the thermal conductivity of a closed porous structure can theoretically be much smaller than that of stationary air if the solid conduction can also be suppressed by (1) lowering the solid content of the material, (2) reducing the thermal conductivity of the building blocks of the material, and/or (3) increasing interfacial thermal resistance between neighboring building blocks. Most processes used to generate porous structures (e.g., supercritical drying, freeze drying) involve a solvent that escapes the material. Therefore, it is difficult to create pores and isolate them simultaneously, preventing the fabrication of super-thermal insulators with closed pores.

36 MATERIALS SCIENCE↗

Ultrathin Atomic Layer Deposited Al 2 O 3 Overcoat Stabilizes Al 2 O 3 -Pt/Ni-Foam Hydrogenation Catalysts

Galvanic exchange seeds the growth of Pt nanostructures on Ni foam monolith. Subsequent atomic layer deposition of ultrathin Al 2 O 3 followed by annealing under air affords supported Pt catalysts with ultralow loading (0.020 ppm). Here, the Al 2 O 3 overcoat plays a crucial role in catalyst stability. In addition to the expected enhancement of the stability of the Pt particles on the surface, the ca. 2 nm Al 2 O 3 overcoat appears to also play a crucial role in the overall structural integrity of the NiO x nanoplates which grow on the Ni foam surface as a result of the preparative route. The resulting material is physically robust towards repeated handling and showcases retention of catalytic activity over ten standard catalyst recycling trials; standing in marked contrast to the uncoated samples. Catalyst activity was tested via the hydrogenation of various functionalized styrenes at low temperatures and low hydrogen pressure in ethanol as solvent, with a TOF as high as 9.5 × 10 6 h -1 for unfunctionalized styrene. Notably, the catalysts show excellent tolerance towards F, Cl, and Br substituents, and no hydrogenation of the aromatic ring.

36 MATERIALS SCIENCE↗

Effect of material properties on batch‐to‐glass conversion kinetics

Abstract A recently developed model of the cold cap—the reacting glass batch (melter feeds) floating on molten glass in an electric glass melter—couples heat transfer with the feed‐to‐glass conversion kinetics. The model allows for determining the distributions of temperature and various properties within the cold cap. In the present study, this model is applied to four melter feeds designed for high‐level and low‐activity nuclear wastes. Profiles of temperature, conversion degree, cold cap porosity and density, condensed matter velocity, and heating rate were determined using the material properties of the cold cap. Effects of vigorous foaming at the cold cap bottom were considered. Density, thermal conductivity, and glass production rate strongly affect the cold cap thickness and the fraction of undissolved silica entering the melt under the cold cap. The heating rate profile in the cold cap is highly nonlinear, with high heating rates observed in the foam layer.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Tuscaloosa Marine Shale Laboratory

The Tuscaloosa Marine Shale (TMS) in Louisiana and Mississippi is an Upper Cretaceous source rock formation sandwiched between the sands of the upper and lower Tuscaloosa sections. The TMS is believed to be the source rock for underlying prolific Tuscaloosa sand formation. The TMS has an unproven estimate of 7,000,000,000 bbls of recoverable oil while its current total average production is about 3,000 bbls of oil per day in 2017. In 2013 and 2014, more than 80 wells were drilled horizontally into the TMS that were fractured using multi-stage fracturing technology. The results from this have been mixed, but recent production for several wells show an appealing initial oil production rate of more than 1000 bbl/day. The preliminary core analysis by industry partners and a few literature studies shows that the TMS is one of the most clay-rich and sensitive shales to water. Due to these and other technical problems, there is high risk for the economic development of TMS compared to other shale plays. The experiences of major industrial players in the TMS show the necessity of open and collaborative efforts to better understand the critical gaps in the development of this challenging and potentially highly economic shale play to enable more cost-efficient and environmentally-sound recovery from this unconventional liquid-rich shale play. The overall objective of this project is to form a consortium of science and industry partners to address the following six major objectives using scientific and technical approaches: 1. To improve wellbore integrity by better understanding the sources of the wellbore instability issues, proposing innovative mud and cement design for the TMS. 2. To improve formation evaluation using laboratory techniques for the evaluation of mineralogical composition, organic content, and produced-water chemistry as well as well log and geophysical analysis. 3. To determine the role of geologic discontinuities on fracture growth and shale creep behavior using digital image correlation technique. 4. To investigate the application of stable CO 2 foam and super-hydrophobic proppants for improved reservoir stimulation. 5. To better understand the nature of water/hydrocarbon/CO 2 flow in clay and organic-rich formation and the role of water/fluid interaction on recovery. 6. To prepare better socio-economic environment for TMS development by community engagement. Subsequently, the TMS virtual laboratory conducted testing and analysis of various properties of rock and formation fluids from the TMS, including but not limited to the following: Analyzing reports and logs to better understand the source of wellbore instability in TMS wells; Experiments to design a customized cement based on TMS requirements; Experiments to obtain the mineralogical and geochemical composition of TMS samples; Seismic analysis of TMS geophysical data to better predict total organic carbon (TOC) content and brittleness in TMS; Well log analysis to better estimate the TOC and geo-mechanical properties of TMS; Experiments on formation water to understand the chemistry of produced water; Experiments to determine the role of lamination and natural fractures on fracture propagation or rock deformation using digital image correlation technique in in-direct tensile tests, semi-circular bend test and creep tests Experiments to determine the stability and rheological properties of nanoparticle-stabilized CO 2 foam in TMS rock samples; Experiments to determine fluid dynamics in un-propped TMS fractures and the role of nano-coating of proppants on fluid dynamics in fractures with proppants; Micro-fluidics experiments to enhance the understanding of fluid dynamics in tight liquidrich pores with high clay content; Socio-economic studies to better engage communities in TMS development.

58 GEOSCIENCES↗

Porous Polymer Structures with Tunable Mechanical Properties Using a Water Emulsion Ink

Recently, the manufacturing of porous polydimethylsiloxane (PDMS) with engineered porosity has gained considerable interest due to its tunable material properties and diverse applications. An innovative approach to control the porosity of PDMS is to use transient liquid phase water to improve its mechanical properties, which has been explored in this work. Adjusting the ratios of deionized water to the PDMS precursor during blending and subsequent curing processes allows for controlled porosity, yielding water emulsion foam with tailored properties. The PDMS-to-water weight ratios were engineered ranging from 100:0 to 10:90, with the 65:35 specimen exhibiting the best mechanical properties with a Young’s Modulus of 1.17 MPa, energy absorption of 0.33 MPa, and compressive strength of 3.50 MPa. This led to a porous sample exhibiting a 31.46% increase in the modulus of elasticity over a bulk PDMS sample. Dowsil SE 1700 was then added, improving the storage capabilities of the precursor. The optimal storage temperature was probed, with -60 °C resulting in great pore stability throughout a three-week duration. The possibility of using these water emulsion foams for paste extrusion additive manufacturing (AM) was also analyzed by implementing a rheological modifier, fumed silica. Fumed silica’s impact on viscosity was examined, revealing that 9 wt% of silica demonstrates optimal rheological behaviors for AM, bearing a viscosity of 10,290 Pa·s while demonstrating shear-thinning and thixotropic behavior. This study suggests that water can be used as pore-formers for PDMS in conjunction with AM to produce engineered materials and structures for aerospace, medical, and defense industries as sensors, microfluidic devices, and lightweight structures.

36 MATERIALS SCIENCE↗