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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 1,135 records · Page 63
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

B a 2 NiOs O 6 : A Dirac-Mott insulator with ferromagnetism near 100 K

In this study, the ferromagnetic semiconductor Ba 2 NiOsO 6 ( T mag ~ 100 K ) was synthesized at 6 GPa and 1500 °C. It crystallizes into a double perovskite structure [Fm - 3m ; a = 8.0428 ( 1 ) Å], where the Ni 2+ and Os 6+ ions are perfectly ordered at the perovskite B site. We show that the spin-orbit coupling of Os 6+ plays an essential role in opening the charge gap. The magnetic state was investigated by density functional theory calculations and powder neutron diffraction. The latter revealed a collinear ferromagnetic order in a > 21 kOe magnetic field at 5 K. The ferromagnetic gapped state is fundamentally different from that of known dilute magnetic semiconductors such as (Ga,Mn)As and (Cd,Mn)Te ( T mag < 180 K ), the spin-gapless semiconductor Mn 2 CoAl ( T mag ~ 720 K ), and the ferromagnetic insulators EuO ( T mag ~ 70 K ) and Bi 3 Cr 3 O 11 ( T mag ~ 220 K ). It is also qualitatively different from known ferrimagnetic insulators and semiconductors, which are characterized by an antiparallel spin arrangement. Our finding of the ferromagnetic semiconductivity of Ba 2 NiOsO 6 should increase interest in the platinum group oxides, because this alternative class of materials should be useful in the development of spintronic, quantum magnetic, and related devices.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Microstructure-Based Understanding of High-Temperature Deformation Behaviors in Laser Powder Bed Fusion (LPBF) 316H Stainless Steel

This report presents the results of high-temperature mechanical property testing and microstructural analysis of laser powder bed fusion (LPBF) 316H stainless steel (SS) conducted during Fiscal Year 2025 (FY25) under the U.S. Department of Energy, Office of Nuclear Energy’s Advanced Materials and Manufacturing Technologies (AMMT) program. The study builds upon prior work by expanding the mechanical property test matrix and advancing a microstructure-based mechanistic understanding of LPBF 316H SS performance, with a focus on the solution annealed (SA, 1100°C for 1 hour) materials. High-temperature tension, creep, fatigue, and creep-fatigue tests were performed. Thermal aging studies were conducted. Advanced characterization techniques, including scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and high-energy synchrotron X-ray diffraction, were employed to investigate the microstructural evolution during thermal aging and mechanical testing. It was discovered that the as-built (AB) LPBF 316H SS exhibited precipitation kinetics during thermal aging that are 10–100 times faster than its wrought counterpart due to the presence of high densities of preferred nucleation sites, while the precipitation kinetics in SA LPBF 316H was under investigation. The accelerated precipitation of embrittling phases such as sigma phase in LPBF 316H SS compared to its wrought counterpart led to significant impacts on creep ductility. The influence of laser printing parameters and build orientations on fatigue and creep-fatigue performance was observed. In assessing the creep-fatigue performance, it was discovered that the SA LPBF 316H samples failed in less than 200 cycles under 595°C, 0.5% (strain amplitude) with a 60-minute hold time. This work establishes a mechanistic framework for predicting the long-term behavior of LPBF 316H SS, supporting its rapid qualification under the ASME BPVC. The findings contribute to the broader goal of enabling the deployment of advanced materials in next-generation nuclear energy systems. An outlook for FY26 work, including continued aging studies, mechanical testing, and microstructural characterization, is provided.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Embedded Aluminum Nitride Sensors for Advanced Reactors

This project aims to manipulate the of growth of aluminum nitride (AlN) inclusions in an iron-chromium-aluminum (FeCrAl) alloy, using the principle of powder metallurgy and heat treatment methods. to promote the formation of AlN phase within FeCrAl for embedded sensing. This effort seeks to fill in a gap with respect to robust sensor hardware for ubiquitous structural health monitoring of advanced nuclear reactors. A systematic evaluation of various solid-state methods will be performed to understand the influence of process conditions on AlN growth and to promote the growth of desirable AlN phase. Fabricated specimens will be analyzed to investigate the AlN structures that are formed using a suite of tools to characterize the concentration, morphology, and distribution of AlN within the FeCrAl substrate.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2021

Czochralski growth and characterization of the multicomponent garnet (Lu 1/4 Yb 1/4 Y 1/4 Gd 1/4 ) 3 Al 5 O 12

This work demonstrates the potential for practical scalable growth of complex garnets and evaluates the implications of a multicomponent composition in the optical quality and elemental distribution of a Czochralski-grown crystal. Furthermore, our experimental approach was designed to elucidate the relation between a complex garnet composition ( Lu 1 / 4 Yb 1 / 4 Y 1 / 4 Gd 1 / 4 ) 3 Al 5 O 12 , crystal growth parameters, crystal structural, and elemental homogeneity. Our hypothesis is that combining multiple rare earths (REs) that will fractionally occupy the dodecahedral site in the aluminum garnet structure will result in a stable, single garnet compound that can be grown by the Czochralski method. Single-crystal and powder x-ray diffraction indicated a single garnet phase with an increasing unit cell volume from seed to tail. In addition, we propose that the pattern of elemental segregation will be based on the deviation of the ionic radius of each constituent RE from the average RE ionic radius of the multicomponent garnet. Electron probe microanalysis revealed that ions that are smaller than that average ( Lu 3 + and Yb 3 + ) are preferentially incorporated in the crystal, while elements that are larger than that average ( Gd 3 + ) are rejected. The ionic radius of Y 3 + is close to that average and yttrium segregation was minimal. The concentrations of the four REs are closer to stoichiometric on the tail end of the boule. Scanning electron microscopy and energy-dispersive x-ray spectroscopy analysis reveal Gd-rich inclusions with eutectic microstructures in the tail end of the boule.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Titanium porous-transport layers for PEM water electrolysis prepared by tape casting

While the porous-transport layer (PTL) is a key component in PEM electrolyzers, it is one of the most underexplored due to limited available structures. In this work, we present a novel PTL design for PEM water electrolyzers enabled by a cost-effective, scalable tape-casting technique. Here, a precise control of the PTL pore structure is achieved by incorporating poreformers of various sizes, and by varying the titanium and poreformer ratio. The structures are characterized with SEM and synchrotron X-ray computed tomography imaging techniques. Comprehensive electrochemical performance analysis demonstrates that higher titanium loading provides improved contact at the catalyst-layer/PTL interface but suffers from severe mass-transport losses due to gas bubbles. We solve this mass-transport problem by mixing in large poreformer beads that produce a highly porous structure with excellent gas removal properties yet still maintaining mechanical integrity. The PTL fabricated with 60:40 Ti:PMMA ratio and 60 μm PMMA bead size outperformed the standard commercial Ti powder-based PTL by 62 mV at 4 A/cm 2 .

25 ENERGY STORAGE↗
DOE OSTI2023

Active site identification and CO oxidation in UiO-66-XX thin films

Metal-organic frameworks (MOFs) offer an intrinsically porous and chemically tunable platform for gas adsorption, separation, and catalysis. Herein we investigate thin film derivatives of the well-studied Zr–O based MOF powders to understand their adsorption properties and reactivity with their adaption to thin films, involving diverse functionality with the incorporation of different linker groups and the inclusion of embedded metal nanoparticles: UiO-66, UiO-66-NH 2 , and Pt@UiO-66-NH 2 . Using transflectance IR spectroscopy, we determine the active sites in each film upon consideration of the acid-base properties of the adsorption sites and guest species, and perform metal-based catalysis with CO oxidation of a Pt@UiO-66-NH 2 film. Our study shows how surface science characterization techniques can be used to characterize the reactivity and the chemical and electronic structure of MOFs.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Chemical crystallography by serial femtosecond X-ray diffraction

Abstract Inorganic–organic hybrid materials represent a large share of newly reported structures, owing to their simple synthetic routes and customizable properties 1 . This proliferation has led to a characterization bottleneck: many hybrid materials are obligate microcrystals with low symmetry and severe radiation sensitivity, interfering with the standard techniques of single-crystal X-ray diffraction 2,3 and electron microdiffraction 4–11 . Here we demonstrate small-molecule serial femtosecond X-ray crystallography (smSFX) for the determination of material crystal structures from microcrystals. We subjected microcrystalline suspensions to X-ray free-electron laser radiation 12,13 and obtained thousands of randomly oriented diffraction patterns. We determined unit cells by aggregating spot-finding results into high-resolution powder diffractograms. After indexing the sparse serial patterns by a graph theory approach 14 , the resulting datasets can be solved and refined using standard tools for single-crystal diffraction data 15–17 . We describe the ab initio structure solutions of mithrene (AgSePh) 18–20 , thiorene (AgSPh) and tethrene (AgTePh), of which the latter two were previously unknown structures. In thiorene, we identify a geometric change in the silver–silver bonding network that is linked to its divergent optoelectronic properties 20 . We demonstrate that smSFX can be applied as a general technique for structure determination of beam-sensitive microcrystalline materials at near-ambient temperature and pressure.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Development of LWR fuels with enhanced accident tolerance. Final report

After a tsunami triggered plant black out at the Fukushima Daiichi site, followed by hydrogen explosions, the US Department of Energy partnered with fuel vendors to study safer alternatives to the current UO2 – zirconium alloy fuel system. This accident tolerant fuel (ATF) alternative should better tolerate a loss of cooling in the core for a considerably longer time while maintaining or improving the fuel performance during normal operation conditions. General Electric, Oak Ridge National Laboratory, and their partners are proposing to replace zirconium alloy cladding in current commercial light water power reactors with an iron-chromium-aluminum (FeCrAl) cladding such as APMT, C26M or FeCrAl ODS, which has been named IronClad by GE. Extensive testing and evaluation has been conducted to determine the suitability of FeCrAl for the entire fuel cycle from rod fabrication to used fuel disposition. Most of the environmental characterization was conducted to evaluate the behavior of IronClad under normal operation conditions and under severe accident conditions. Results show that FeCrAl has excellent corrosion resistance under normal operation conditions and FeCrAl is several orders of magnitude more resistant than zirconium alloys to degradation by superheated steam under accident conditions, generating less heat of oxidation and lower amount of combustible hydrogen gas. Higher parasitic neutron absorption and potential tritium release into the coolant effects can be minimized by design and operational measures. IronClad material can be manufactured using traditional melting and forging (C26M) or powder metallurgy processes (APMT & FeCrAl ODS). Tubes can be made to full length of 5 m with a wall thickness of 0.4 mm by pilgering or drawing. The fuel rods can be readily hermetically sealed in an industrial production setting by welding end caps to the thin wall tubing using either TIG or resistance welding. The implementation of FeCrAl IronClad cladding is a near term solution to enhance the safety of the current fleet of commercial light water power reactors.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

Computational Model and Characterization of Stacking Faults in ZIF-8 Polymorphs

Degradation of metal–organic frameworks (MOFs) in aqueous, humid, and acid gas environments likely begins at defect sites. Until now, however, theoretical studies of MOFs have widely assumed an ideal defect-free structure. Here we present a computational model for low-energy extended defects in bulk zeolitic imidazolate frameworks (ZIFs) that are analogous to stacking faults in zeolites. We demonstrate the thermodynamic accessibility of stacking faults in ZIFs and examine the impact of these defects on pore diffusion and accessible surface area. We identify strong correlations between the defect density of a structure and its X-ray diffraction spectra. Finally, by examining a topologically isomorphic ZIF that has been reported experimentally we find characteristic defect-induced peak broadening and splitting in the reported powder patterns, giving strong evidence for the existence for stacking faults in this material.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

ASb 3 Mn 9 O 19 (A = K or Rb): New Mn-Based 2D Magnetoplumbites with Geometric and Magnetic Frustration

Magnetoplumbites are one of the most broadly studied families of hexagonal ferrites, typically with high magnetic ordering temperatures, making them excellent candidates for permanent magnets. However, magnetic frustration is rarely observed in magnetoplumbites. Herein, the discovery, synthesis, and characterization of the first Mn-based magnetoplumbite, as well as the first magnetoplumbite involving pnictogens (Sb), ASb 3 Mn 9 O 19 (A = K or Rb) are reported. The Mn 3+ ( S = 2) cations, further confirmed by DC magnetic susceptibility and X-ray photoelectron spectroscopy, construct three geometrically frustrated sublattices, including Kagome, triangular, and puckered honeycomb lattices. Magnetic properties measurements revealed strong antiferromagnetic spin–spin coupling as well as multiple low-temperature magnetic features. Heat capacity data does not show any prominent λ-anomaly, suggesting minimal associated magnetic entropy. Moreover, neutron powder diffraction (NPD) implied the absence of long-range magnetic ordering in KSb 3 Mn 9 O 19 down to 3 K. However, several magnetic peaks are observed in RbSb 3 Mn 9 O 19 at 3 K, corresponding to an incommensurate magnetic structure. Interestingly, strong diffuse scattering is seen in the NPD patterns of both compounds at low angles and is analyzed by reverse Monte Carlo refinements, indicating short-range spin ordering related to frustrated magnetism as well as 2D magnetic correlations in ASb 3 Mn 9 O 19 (A = K or Rb).

2-D magnetic correlation↗
DOE OSTI2019

Effect of laser power on defect, texture, and microstructure of a laser powder bed fusion processed 316L stainless steel

The effect of laser power on defect characteristics, microstructure development, constituent phases, and crystallographic texture was studied on a laser powder bed fusion (L-PBF) processed 316L stainless steel. A series of cylindrical specimens were additively manufactured as a function of laser power ranging from 380 to 200W with a fixed scan speed of 300 mm/s using a selective laser melting system. The density (in terms of count, surface area, and porosity), size (mean values of major axis length, surface area, and volume), shape (aspect ratio and sphericity), and orientation (in terms of the angle between the major axis and build direction) of macroscopic defects in as-printed L-PBF cylinders were characterized using high-resolution synchrotron x-ray computed microtomography with a 0.65μm resolution. Moreover, the changes in the preferred crystallographic orientations and constituent phases were investigated using high-energy synchrotron x-ray diffraction. Finally, the melt pool shape and grain size/orientation were analyzed using metallography. The results show that the porosity increases linearly from 0.13 to 0.88% with the decrease in laser power. However, even with the decrease in laser power by about half and corresponding seven-fold increase in porosity, the 200W case can still be considered as nearly fully dense. On the other hand, with the same decrease in the laser power, the melt pool size/shape, grain size, and texture changed significantly. In conclusion, the role of energy input in the simultaneous changes in defect properties and microstructure development will be discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Microscopic Characterization of Pb 10−x Cu x (PO 4 ) 6 O by 31 P and 63/65 Cu NMR Measurements

The report of the first room-temperature, ambient-pressure superconductivity in copper-doped lead apatite Pb 10−x Cu x (PO 4 ) 6 O has attracted lots of attention. However, subsequent studies revealed the presence of numerous impurity phases in the polycrystalline sample, and the sharp superconducting-like transition is not due to a superconducting transition but most likely due to a reduction in resistivity caused by the first-order structural phase transition of Cu 2 S at around 385 K from the β phase at high temperature to the γ phase at low temperature. Before now, only bulk measurements have been performed on a Pb 10−x Cu x (PO 4 ) 6 O powder sample, which could be affected by the impurity phases, masking the intrinsic properties of Pb 10−x Cu x (PO 4 ) 6 O. In this study, 31 P and 63/65 Cu nuclear magnetic resonance (NMR) measurements have been performed on a Pb 10−x Cu x (PO 4 ) 6 O powder sample to investigate its physical properties from a microscopic point of view. Our NMR data evidence the non-magnetic insulating nature of Pb 10−x Cu x (PO 4 ) 6 O without any trace of electron correlation effects. Furthermore, the 63/65 Cu NMR results suggest that no copper or very little copper is substituted for Pb in Pb 10 (PO 4 ) 6 O prepared by sintering Pb 2 SO 5 and Cu 3 P.

lead apatite↗
DOE OSTI2018

Unordinary Ferromagnetic Phase Transitions in Mn- and Fe-doped Half-Heusler CoTiSb

Unordinary ferromagnetic character and high Curie temperature around 900 K have been detected for CoTi {sub 1−x}M{sub x}Sb (M = Mn and Fe, x = 0.1) multiphases systems. The synthesis process was carried out at high temperature in evacuated quartz tubes. The x-ray powder diffraction analysis through Rietveld method was applied to refine the crystal structure. By manipulating the search match program, three nanocrystalline phases of CoTiSb (64.5%), CoSb (15.5%), and TiSb{sub 2} (20.5%) for Mn-doped system and CoTiSb (33%), Ti{sub 3}Sb (35.3%), and CoTi{sub 2} (30.7%) for Fe-doped system were recognized. The term “phase” was used to address the coexistence of different stable chemical compositions for the same half-Heusler alloy. The scanning electron microscope (SEM) and the high-resolution transmission electron microscope (HR-TEM) were applied to characterize the morphology, size, shape, crystallinity and lattice spacing. Good matching was detected between the obtained d values using electron diffraction data and those calculated from x-ray analysis. Well defined nanocrystalline structure with average interatomic distances equaling 0.229 nm, 0.286 nm together with many successive rings with sharp diffraction spots characterized the Fe-doped system. In contrast, partially distorted structured planes and smeared halo surrounded by weak rings were detected in the Mn-doped system. Thermo-magnetic measurements (M-T) were performed for both systems. In addition to Curie transition, many magnetic phase transitions were detected and confirmed through the ΔM/ ΔT vs. T relationship. The field-dependence magnetization (M-H) was measured at different temperatures. The M-H hysteresis loops showed the ferromagnetic character for both systems. Tentative magnetic phase diagrams are suggested as a guide for future research.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Crystal field splittings and magnetic ground state of the square-lattice antiferromagnets YbBi 2 ⁢ClO 4 and YbBi 2 ⁢IO 4 with J eff = $\frac{1}{2}$

Here, we report on the crystal field level splitting and magnetic ground state of the J eff = $\frac{1}{2}$ square lattice antiferromagnets YbBi 2 ⁢ClO 4 and YbBi 2 ⁢IO 4 using powder inelastic neutron scattering (INS) and neutron diffraction measurements. Both compounds exhibit a well-isolated Γ 7 doublet ground state under a tetragonal crystal field environment, confirming a robust J eff = $\frac{1}{2}$ picture with slight XY-type anisotropic character in the g-tensor. Notably, the ground state wave functions closely resemble the Γ 7 doublet expected in the perfect cubic limit, consistent with the nearly cubic ligand configuration of eight O 2- ions surrounding Yb 3+ . Below T N = 0.21 K, YbBi 2 ⁢IO 4 exhibits a stripe long-range magnetic order characterized by an ordering wave vector q m = (1/2, 0, 0) or its symmetry-equivalent (0, 1/2, 0), with magnetic moments aligned along q m . The ordered moment is approximately 79% of the classical prediction, significantly larger than expected from the isotropic J 1 -J 2 model, suggesting the possible involvement of exchange anisotropy in explaining this observation. We show that symmetry-allowed XXZ and bond-dependent anisotropic exchange terms in a square lattice can play a critical role in stabilizing the stripe order and suppressing the moment reduction as observed. These findings establish YbBi 2 ⁢ClO 4 and YbBi 2 ⁢IO 4 as unique platforms for exploring rich J eff = $\frac{1}{2}$ magnetism from two less investigated perspectives: (i) on a square lattice and (ii) within a (nearly) cubic ligand environment.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Influence of Ba Substitutions on Microstructure and Magnetic Properties of La–Ca–Co System Permanent Ferrite

La{sub 0.6}Ca{sub 0.4−x}Ba{sub x}O⋅n/2(Fe{sub 1−y}Co{sub y}){sub 2}O{sub 3}(x = 0, 0.05, 0.1, 0.15 and 0.2) permanent ferrite materials were prepared by ceramic technique. The topography and the structure were characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD), respectively. The magnetic properties were measured using vibrating sample magnetometer (VSM) and digital magnetometer. Single M-phase and flake-like grains were obtained for samples without Ba substitution(x = 0), and the magnetic properties of the pre-sintering La–Ca–Co ferrite were as follows: B{sub r} = 440 mT, H{sub cb} = 296 kA/m, H{sub cj} = 426 kA/m, (BH){sub max} = 36.6 kJ/m{sup 3} and H{sub k}/H{sub cj} = 0.83. When Ca was substituted by Ba, pre-sintered powder presents single M-phase structure and close three-dimensional size of grains, resulting in an improved rectangle ratio of sintered magnet. The rectangle ratio of sintered magnet reaches a maximum of 0.93 when x = 0.1. By optimizing process parameters, M-type La–Ca–Ba–Co sintered magnet was prepared with B{sub r} = 445 mT, H{sub cb} = 337 kA/m, H{sub cj} = 420 kA/m, (BH){sub max} = 38.6 kJ/m{sup 3} and H{sub k}/H{sub cj} = 0.95.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Development of Solid Synchronous Reluctance Rotors With Multi-Material Additive Manufacturing

Synchronous reluctance (SynR) machines are promising rare-earth material-free alternatives to permanent magnet machines. However, structural challenges limit their operating speed and power density. This paper proposes and investigates multi-material additive manufacturing (MMAM) as a key-enabler to realize power-dense and high-speed SynR machines. It does so by proposing designs that guide magnetic flux through solid rotors realized by selective placement of magnetic and non-magnetic materials. To explore this concept, first, material samples are additively manufactured and experimentally characterized to assess the structural and magnetic properties that can be expected for the proposed rotors. Second, the design space of each rotor type is explored using these measured properties within finite element analysis. The results reveal that MMAM can enable fabrication of SynR motors with power density levels that are at the leading edge of all conventional electric machine topologies. It is shown that tip speeds in excess of 300 m/s can be achieved, resulting in 3-4x improvement in power density over conventional SynR motors. A solid SynR rotor is printed in an experimental MMAM laser powder bed fusion system. The rotor is paired with an existing stator to create a functional SynR motor with a saliency ratio of 2.59 and torque rating of 4.15 Nm. This is the first publication of a SynR rotor prototype constructed via MMAM.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Coupled Hydrothermal Extraction and Ligand-Associated Swellable Glass Media Recovery of Rare Earth Elements from Coal Fly Ash (Final Report)

Wayne State University (WSU) researchers, in collaboration with the University of California-Los Angeles (UCLA) and Los Alamos National Laboratory (LANL), have successfully developed a new sorbent media used in a process that concentrated the rare earth content in a coal fly ash sample from southeast MI by >350×, resulting in >13 wt% REO powder. The project developed a new DTPA-associated media that was used to concentrate total REEs. This project demonstrated a coupled hydrothermal extraction and solid-liquid recovery process that produced REO powder from raw fly ash while nearly eliminating the use of organic solvents. The project successfully: 1) identified a commercially viable ash supply with >$2.5 M in REO value being deposited monthly, 2) hydrothermally extracted >77% of REEs in coal fly ash (20% more than acid alone), 3) developed a new sorbent media that was used to concentrate REEs, 4) and engineered a process that resulted in a >13 wt% REO powder. The media also demonstrates a selectivity for mid and heavy REEs over Ce and La and the potential for use in separating individual rare earth elements. An invention disclosure for the sorbent media has been filed with WSU and a patent application will be submitted in the near future. The project examined the potential to couple hydrothermal leaching of coal fly ash with the engineering of a custom ligand-associated media to provide an organic solvent-free method of extracting and recovering REEs. Fly ash feedstock was collected from Detroit area coal-fired power plants, characterized for REE content, and subjected to a bench-top batch hydrothermal leaching/dissolution process inside custom-build pressure reactors at Los Alamos National Laboratory (LANL). This process applied a dissolution technique previously developed to process spent nuclear fuel and other nuclear materials. The modified ash was acidified and the resulting leachate was enriched with REEs along with Ca, Al, and Si. Ligands known to be effective in lanthanide/actinide separation were evaluated based on a series of criteria such as selectivity and association to organosilica through hydrophobicity. Batch experiments were conducted to establish the best conditions (e.g., pH, eluent, etc.) and best ligand systems for the effective extraction of REEs from the alkaline feed solution obtained from the hydrothermal leaching process. Once the organosilica-ligand extraction media was developed for REE concentration, an acidic solution was used to back extract and concentrate the REEs into a heavily REE-laden strip solution. The REEs in the strip solution were precipitated with oxalate to produce rare earth oxides.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2018

Thermal Safety Characterization of HMX, LX-07, PBX 9502, and XTX-8004 in the ODTX System

Incidents caused by fire and combat operations can heat energetic materials that may lead to thermal explosion and result in structural damage and casualty. Some explosives may thermally explode at fairly low temperatures (< 100 C) and the violence from thermal explosion may cause a significant damage. Thus, it is important to understand the response of energetic materials to thermal insults. The One- Dimensional-Time to Explosion (ODTX) system at the Lawrence Livermore National Laboratory has been used for decades to measure times to thermal explosion, threshold thermal explosion temperature, and to determine the kinetic parameters of thermal decomposition of energetic materials. The kinetic parameters are being used to construct predictive models for thermal safety assessment on systems that use the energetic materials. Samples of different configurations (pressed part, powder, paste, and liquid) can be tested in the system. This report summarizes the results of our recent ODTX experiments on 4 energetic materials from 2016 to 2018: HMX (class 1 and class 2), LX-07 (two densities), PBX 9502 (two densities) and XTX-8004, lot C-639. Extensive P-ODTX testing was also performed on the 4 energetic materials and the results will be summarized in a separate report.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗