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At least 703 records · Page 39

AGR-2 and AGR-3/4 Release-to-Birth Ratio Data Analysis

A series of Advanced Gas Reactor (AGR) irradiation tests is being conducted in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) in support of development and qualification of tristructural isotropic (TRISO) low enriched fuel used in the High Temperature Gas-cooled Reactor (HTGR). Each AGR test consists of multiple independently controlled and monitored capsules containing fuel compacts placed in a graphite cylinder shrouded by a steel shell. These capsules are instrumented with thermocouples embedded in the graphite enabling temperature control. AGR configuration and irradiation conditions are based on prismatic HTGR technology that is distinguished primarily through use of helium coolant, a low-power-density ceramic core capable of withstanding very high temperatures, and TRISO coated particle fuel. Thus, these tests provide valuable irradiation performance data to support fuel process development, qualify fuel for normal operating conditions, and support development and validation of fuel performance and fission product transport models and codes.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Prototype Testing of Encapsulated Phase Change Material Thermal Energy Storage (EPCM-TES) for Concentrated Solar Power

In the present study, experimental investigations were conducted on encapsulated phase-change material (EPCM) capsules from Terrafore Technologies. Several aspects of the EPCM capsules were evaluated, including shell fracture stress under compression and melting/solidification performance. The stress testing was conducted with the Instron universal test system, and the melting/solidification testing was conducted in Argonne National Laboratory’s high-temperature thermal energy storage test system. Results on the EPCM fracture stress, the melting/solidification characteristics of the EPCM capsules, the temperature repeatability under similar test conditions, and the heat balance for melting/solidification processes are presented in this report.

14 SOLAR ENERGY↗

AGR-1, AGR-2 and AGR-3/4 Release-to-Birth Ratio Data Analysis

A series of Advanced Gas Reactor (AGR) irradiation tests is being conducted in the Advanced Test Reactor at Idaho National Laboratory in support of development and qualification of tristructural isotropic (TRISO) low enriched fuel used in the High Temperature Gas-cooled Reactor (HTGR). Each AGR test consists of multiple independently controlled and monitored capsules containing fuel compacts placed in a graphite cylinder shrouded by a steel shell. These capsules are instrumented with thermocouples embedded in the graphite enabling temperature control. AGR configuration and irradiation conditions are based on prismatic HTGR technology distinguished primarily by the use of helium coolant, a low-power-density ceramic core capable of withstanding very high temperatures, and TRISO coated particle fuel. Thus, these tests provide valuable irradiation performance data to support fuel process development, qualify fuel for normal operating conditions, and support development and validation of fuel performance and fission product transport models and codes. The release-rate-to-birth-rate ratio (R/B) for each of fission product isotopes (i.e., krypton and xenon) is calculated from release rates in the sweep gas flow measured by the germanium detectors used in the AGR Fission Product Monitoring (FPM) System installed downstream from each irradiated capsule. Birth rates are calculated based on the fission power in the experiment and fission product generation models. Thus, this R/B is a measure of the ability of fuel kernel, particle coating layers, and compact matrix to retain fission gas atoms preventing their release into the sweep gas flow, especially in the event of particle coating failures that occurred during AGR-2 and AGR-3/4 irradiations. The major factors that govern gaseous radioactive decay, diffusion, and release processes are found to be material diffusion coefficient, temperature, and isotopic decay constant. For each of all AGR capsules, ABAQUS-based three-dimensional finite-element thermal models are created to predict daily averages of fuel compact temperatures for the entire irradiation period, which are used in establishing the R/B correlation with temperature and decay constant. This correlation can be used by reactor designers to estimate fission gas release from postulated failed fuel particles in HTGR cores, which is the key safety factor for fuel performance assessment.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

AGR-2 and AGR-3/4 Release-to-Birth Ratio Data Analysis

A series of Advanced Gas Reactor (AGR) irradiation tests is being conducted in the Advanced Test Reactor at Idaho National Laboratory in support of development and qualification of tristructural isotropic (TRISO) low enriched fuel used in the High Temperature Gas-cooled Reactor (HTGR). Each AGR test consists of multiple independently controlled and monitored capsules containing fuel compacts placed in a graphite cylinder shrouded by a steel shell. These capsules are instrumented with thermocouples embedded in the graphite enabling temperature control. AGR configuration and irradiation conditions are based on prismatic HTGR technology distinguished primarily by the use of helium coolant, a low-power-density ceramic core capable of withstanding very high temperatures, and TRISO coated particle fuel. Thus, these tests provide valuable irradiation performance data to support fuel process development, qualify fuel for normal operating conditions, and support development and validation of fuel performance and fission product transport models and codes. The release-rate-to-birth-rate ratio (R/B) for each of fission product isotopes (i.e., krypton and xenon) is calculated from release rates in the sweep gas flow measured by the germanium detectors used in the AGR Fission Product Monitoring (FPM) System installed downstream from each irradiated capsule. Birth rates are calculated based on the fission power in the experiment and fission product generation models. Thus, this R/B is a measure of the ability of fuel kernel, particle coating layers, and compact matrix to retain fission gas atoms preventing their release into the sweep gas flow, especially in the event of particle coating failures that occurred during AGR-2 and AGR-3/4 irradiations. The major factors that govern gaseous radioactive decay, diffusion, and release processes are found to be material diffusion coefficient, temperature, and isotopic decay constant. For each of all AGR capsules, ABAQUS-based three-dimensional finite-element thermal models are created to predict daily averages of fuel compact temperatures for the entire irradiation period, which are used in establishing the R/B correlation with temperature and decay constant. This correlation can be used by reactor designers to estimate fission gas release from postulated failed fuel particles in HTGR cores, which is the key safety factor for fuel performance assessment.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Carbon molecular sieve membrane for gas separations

An ultrathin high permselectivity carbon molecular sieve membrane (CMSM) for industrial gas separations is provided. The CMSM includes porous metal or ceramic supports to provide superior stability at high temperatures, pressures and chemical environments. The CMSM also offers the potential for cost-effective gas processing while overcoming disadvantages found in alternative media that are fragile and susceptible to shock due to thermal cycling and prone to end-sealing problems under industrial conditions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Electronic transport of titanate heterostructures and their potential as channels on (001) Si

Perovskite oxides and their heterostructures have demonstrated considerable potential for devices that require high carrier densities. These oxides are typically grown on ceramic substrates that suffer from low thermal conductivity, which limits performance under high currents, and from the limited size of substrates, which precludes large scale integration and processing. We address both of these hurdles by integrating oxide heterostructures with high carrier density 2D electron gases (2DEGs) directly on (001) Si. 2DEGs grown on Si show significant improvement of the high current performance over those grown on oxide substrates, a consequence of the higher thermal conductivity of the substrate. Hall analysis, transmission line measurements, and the conductance technique are employed for a detailed analysis of the carrier density, contact resistance, mobility, and electron drift velocities. Current densities of 10 A/cm are observed at room temperature with 2.9 × 10{sup 14} electrons/cm{sup 2} at a drift velocity exceeding 3.5 × 10{sup 5 }cm/s. These results highlight the promise of oxide 2DEGs integration on Si as channels for high electron density devices.

36 MATERIALS SCIENCE↗

Mechanical relaxation in thermoelectric oxide Ca{sub 3−x}Sr{sub x}Co{sub 4}O{sub 9+δ} (x=0, 0.25, 0.5, 1.0) associated with oxygen vacancies

Ca{sub 3}Co{sub 4}O{sub 9+δ} has a unique structure that leads to exceptionally good thermoelectric (TE) properties. To change the concentration of oxygen vacancies (OVs) of the sample, the same sintered Ca{sub 3}Co{sub 4}O{sub 9+δ} polycrystalline ceramic suffered treating in 30 wt% oxydol (H{sub 2}O{sub 2}) solution and then annealing at 600 °C in pure N{sub 2}-gas atmosphere. Before and after each treatment, we performed dynamic mechanical analysis (DMA) with different frequencies, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) on the sample. A relaxation peak was observed at the temperature range from 90 °C to 150 °C, and the relaxation process is most likely caused by the migration of single OVs. The consistency in the results from TGA and XPS could well support the conclusion that the OVs of Ca{sub 3}Co{sub 4}O{sub 9+δ} are located on the O site of CoO layer in Ca{sub 2}CoO{sub 3} subsystem. Further DMA investigations on the Ca{sub 3−x}Sr{sub x}Co{sub 4}O{sub 9+δ} (x=0, 0.25, 0.5, 1.0) ceramic indicated that Sr substitution of Ca could suppress the relaxation peak, suggesting the migration of single OVs mainly processes between CoO and CaO layers of Ca{sub 2}CoO{sub 3} subsystem. - Graphical abstract: A relaxation peak and a transition peak could be observed in the internal friction spectra of Ca{sub 3}Co{sub 4}O{sub 9+δ}. The calculated activation energy indicates the relaxation process is associated with migration of oxygen vacancies. Highlights: ► We performed dynamic mechanical analysis on the thermoelectric oxide Ca{sub 3}Co{sub 4}O{sub 9+δ}. ► We observed a relaxation peak and a transition peak. ► The oxygen vacancies are located in CoO layer of Ca{sub 2}CoO{sub 3} subsystem. ► The relaxation peak originates from migration of single oxygen vacancies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Editorial: Functionalization of porous materials for sustainable energy applications

Global energy demands are shifting toward a more sustainable future, with the goal of achieving carbon neutrality by 2050. Emerging technologies are driving this transition. The industry, academia, government, non-profit organizations, and the broader community are collaboratively working to reduce greenhouse gas (GHG) emissions and address climate change to ensure a sustainable future. According to the International Energy Agency, in 2022, the production, transportation, and processing of oil and gas resulted in 5.1 billion tons of CO 2 -equivalent emissions, representing nearly 15% of all energy-related GHG emissions. Moreover, the end-use of oil and gas accounted for an additional 40% of emissions. The IEA’s Net Zero Emissions by 2050 Scenario calls for immediate, collective action from the industry, transportation and other stakeholders to mitigate these emissions. In this effort, the development of energy materials will play a critical role in reducing emissions. Among these, porous materials offer an innovative solution, leveraging their high surface area, adjustable pore sizes, and chemical versatility to address these pressing challenges effectively. By carefully designing their nanostructures, the architecture and properties of these materials can be tailored for specific applications. Key factors such as chemical composition, particle size, pore distribution, and surface area optimization enhance the reactivity and energy conversion efficiency. Additionally, pre- and post-functionalization processes can introduce targeted chemical properties, further improving their performance. This Research Topic explores recent advancements in energy and materials science through four scholarly papers, showcasing innovative solutions for sustainable energy technologies while providing valuable insights into the unique properties and structure of porous materials (Figure 1). Li et al. present their work on highly defective NiFeV layered triple hydroxides, highlighting enhanced electrocatalytic activity and stability for oxygen evolution reactions (OER). Kovalskii et al. contribute a mini-review on hydrogen storage using hexagonal boron nitride (h-BN) and BN-based materials, offering an insightful overview of these promising materials. Chava et al. discuss their recent achievements in ceramic electrolytes used for improvement of performance of solid-state batteries. Lastly, Li et al. review the properties of porous materials with a focus on shrinkage behavior during the drying process, shedding light on key considerations for material design.

36 MATERIALS SCIENCE↗

Development of Glass and Glass Ceramic Proppants from Gas Shale Well Drill Cuttings

The objective of this study was to develop a method of converting drill cuttings from gas shale wells into high strength proppants via flame spheroidization and devitrification processing. Conversion of drill cuttings to spherical particles was only possible for small particle sizes (< 53 μm) using a flame former after a homogenizing melting step. This size limitation is likely to be impractical for application as conventional proppants due to particle packing characteristics. In an attempt to overcome the particle size limitation, sodium and calcium were added to the drill cuttings to act as fluxes during the spheroidization process. However, the flame former remained unable to form spheres from the fluxed material at the relatively large diameters (0.5 - 2 mm) targeted for proppants. For future work, the flame former could be modified to operate at higher temperature or longer residence time in order to produce larger, spherical materials. Post spheroidization heat treatments should be investigated to tailor the final phase assemblage for high strength and sufficient chemical durability.

03 NATURAL GAS↗

Laser-induced slip casting as an additive manufacturing approach for silicon carbide

Here, this work presents processing silicon carbide (SiC) with the laser-induced slip casting (LIS) additive manufacturing (AM). SiC was stabilized in water with polyethyleneimine (PEI) dispersant, and SiC slurries were made with rheology for LIS printing. High-density ceramic parts were printed, followed by single-step binder burnout and sintering. The printed parts achieved 93–95 % of theoretical density. X-ray computed tomography (XCT) revealed a small distribution of flaws exceeding 100 microns. The mechanical properties were measured in both parallel and perpendicular to the printing layers, and the orientation with layers perpendicular to the bending moment resulted in higher strength compared to the parallel direction. Porosity resulting from processing and large inclusions of boron carbide (B4C) were the root cause of failure in the measured samples. Despite these defects through this effort, this new approach demonstrates promise for green forming of SiC with densities greater than 95 % theoretical and tensile strengths above 250 MPa.

Additive Manufacturing↗

Design of Circular, Square, Single, and Multi-layer Induction Coils for Electromagnetic Priming Using Inductance Estimates

Special induction coils used for electro magnetic priming of ceramic foam filters in liquid metal filtration have been designed using a combination of analytical and finite element modeling. Relatively simple empirical equations published by Wheeler in 1928 and 1982 have been used during the design process. The equations were found to accurately predict the z-component of the magnetic flux densities of both single- and multi-layer coils as verified both experimentally and by using COMSOL{sup ®} 5.1 multiphysics simulations.

36 MATERIALS SCIENCE↗

Miniature low-pass filter in low-loss 9k7 LTCC

DuPont 9k7 low-temperature cofired ceramic (LTCC) is a low-loss, or high-quality-factor Q, tape system targeting at radio frequency (RF) applications. This paper reports on the effect of a critical process parameter, the heating rate, on the densification and dielectric properties of the 9k7 LTCC. The role of competing densification and crystallization during the sintering of 9k7 is discussed. The high Q of DuPont 9K7 can be used to improve RF system performance, for example a better receiver noise figure, by designing embedded passive RF components such as inductors, capacitors and filters. Furthermore, miniaturized multilayer low-pass filters (LPF) with a wide stopband were fabricated to showcase the technology.

36 MATERIALS SCIENCE↗

Rolling Behavior of Surface Tagged Aluminum 6061 using Photoluminescent Oxides

Physical tagging of nuclear fuel is potentially one way of tracking throughout the fuel lifecycle. The process of tagging can take many forms, but one promising method is to embed a small amount of photoluminescent particles in the surface of a material which are not detectable under normal illumination but are readily visible under excitation by ultraviolet light. The goal of this project was to explore the potential to tag simulated nuclear fuel cladding with small ceramic particles, via laser beam welding or gas tungsten arc welding, and measure the photoluminescent response. Surface tagging using this method has demonstrated viability and detectability throughout this project; work in FY24 focused on the survivability of these tags through subsequent deformation processing similar to what taggants in a fuel manufacturing environment would be subjected to. This work demonstrated that particles are readily visible in the as-welded state (i.e., before subsequent rolling treatment to represent mechanical processing of a fuel material), but visibility is reduced as the deformation is induced. Despite the reduction in photoluminescence, the taggants are still visible after rolling processes are performed, making this surface tagging technique a promising candidate for nuclear fuel cladding tagging. This work demonstrated, though, that targeted optimization work would be necessary to develop a robust taggant depending on the fidelity and luminescent properties required.

36 MATERIALS SCIENCE↗

Phase Field Modeling of Pressure Induced Densification in Solid Electrolytes

Adoption of dense and homogeneous solid electrolytes can possibly mitigate the propagation of lithium dendrites and enable lithium metal anodes. Application of external pressure helps to minimize the sintering temperature in oxide ceramics and can potentially densify softer sulfide electrolytes even under room temperature conditions. Here, a previously developed phase field-based computational scheme for predicting the high-temperature sintering-induced densification of oxide ceramic solid electrolytes is extended in the present context to capture the influence of external pressure for densifying solid electrolytes. Two different bulk deformation mechanisms, namely, "reorganization" and "creep deformation," are dominant under external pressure, which is different from the surface and grain-boundary diffusion-induced densification of solid electrolytes that occurs during high temperature sintering. External pressure also increases the points of contact between the particles, which further enhances the propensity of diffusion-induced sintering process. Results obtained from simulations indicate that densification under external pressure is independent of the solid electrolyte particle morphology. Finally, a phase map is generated between applied pressure and temperature for achieving complete densification of oxide ceramics, which can possibly guide the synthesis of thin and dense solid electrolyte separators.

25 ENERGY STORAGE↗

Savannah River Site Defense Waste Processing Facility Melt Cell Remote Cleanup - 18037

This paper documents experiences at Savannah River Site (SRS) related to both the modification and use of a commercial remote vehicle to remove years of process-related litter (glass and various objects) from a hot cell floor during a production outage. The outage was necessary to replace a Department of Energy Environmental Management (DOE-EM) remotely-operated glass melter that had vitrified waste for 14 years at the Defense Waste Processing Facility. Both chunks of waste glass and numerous items littered the floor of the cell all associated with the long production run. The presence of litter become problematic as it could eventually impede movement or placement of items necessary to continue facility operation. The cleanup also reduces radiation rates within the hot cell which is beneficial. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Optimized Slurries for Spray Drying: Different Approaches to Obtain Homogeneous and Deformable Alumina-Zirconia Granules

Spray drying is widely used for producing granulated feed materials for compaction process, which is the current industrial method for manufacturing alumina-zirconia femoral heads. The optimization of the granules compaction behavior requires the control of the slurry rheology. Moreover, for a dual-phase ceramic suspension, the even phase distribution has to be kept through the atomization step. Here we present two approaches addressing the key issues involved in the atomization of a composite system. Alumina-10 vol % zirconia powders were prepared by either a powder mixing route, or by the surface modification of a commercial α-alumina powder with a zirconium salt. Slurries from both powders were spray dried. The correlation between slurry rheology and pH, granules morphology and sintered microstructures was here investigated and discussed on the ground of the two feed materials characteristics. The processing conditions were optimized to obtain dense and homogeneous alumina-zirconia micro-nano composites by both processing routes.

36 MATERIALS SCIENCE↗

Spark Plasma Sintering of W-UO2 Cermets

About 50 vol.% 3 um depleted uranium dioxide (UO2) powder was encapsulated within a tungsten super alloy matrix produced from sub-micron tungsten powders using the Spark Plasma Sintering (SPS) process. An additive of 25 atom-percent (at.%) rhenium was included within the tungsten matrix to improve the ductility and fracture toughness of the ceramic–metallic (cermet) matrix. Cermet fabrication to 97.9% of the theoretical cermet density was achieved by sintering at 1500 degrees C with 40 MPa of applied pressure for 20 min. The results presented are from the first known trials of W–UO2 and nuclear cermet production via SPS.

36 MATERIALS SCIENCE↗

Pre-ceramic polymer-assisted nucleation and growth of copper sulfide nanoplates

Abstract Polymer-derived ceramics derived from pre-ceramic polymers (PCPs), have access to several form factors and are highly tunable systems. Tunability can be further expanded with the incorporation of functional nanoparticle fillers throughout the matrix for advanced nanocomposite polymer-derived ceramic development. However, capping ligands used in nanoparticle syntheses mix unfavorably with PCPs, giving aggregated filler material and diminished properties. To control dispersion, secondary nanoparticle processing is performed by adhering PCP-miscible caps to the surface after synthesis. This often sacrifices size control established for small nanoparticles (<10 nm). Herein, we successfully eliminate the need for extra nanoparticle processing through the development of a one-pot, copper sulfide synthesis in which a PCP assists the stable formation of nanoparticles and serves as the final graft molecule. We monitor the success of this methodology and the PCP’s role in the reaction through several characterization methods probing both the nanoparticle core and polymer graft.

Loughney, Patricia A. (ORCID:0000000199472267)↗