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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Experimental validation of the mechanistic scale-up methodology of gas–solid spouted beds using radioactive particle tracking (RPT)

The very high-temperature reactors (VHTRs) are highly ranked among candidates of Generation IV of nuclear reactors due to their high efficiency, safety, the resistance to proliferation, and reliability. The VHTRs are preferentially fueled by Tristructural-isometric (TRISO) coated fuel particles which has fuel kernels of fissile material coated by four coating layers: a porous buffer pyrolysis carbon layer (buffer PyC), an inner dense pyrolysis carbon layer (IPyC), a silicon carbide layer (SiC) and an outer dense pyrolysis carbon layer (OPyC). The heart of the operation and safety of the VHTRs significantly depends on the reliability of the coating layers of TRISO particles to retain metallic and gaseous fission products within the particles. The technique used for coating TRISO particles are gas-solids spouted beds via chemical vapor deposition (CVD). Fabrication of high-quality low-defect TRISO fuel particles fuel at larger scale spouted beds is required to support the commercialization of the VHTRs. In this work, our new developed mechanistic scale-up methodology of gas-solids spouted beds based on matching the radial profile of gas-holdup has been demonstrated and validated using radioactive particle tracking (RPT). Two spouted beds of small and larger scales were used in the study. Three sets of conditions were carried out which include the conditions of the reference case in the large scale, conditions that provide similar gas holdup radial profile to that of the reference case and conditions that provided dissimilar gas holdup radial in the small-scale spouted beds. The results confirm the validation of the scale-up methodology in terms of the dimensionless values of the spout diameter, cumulative probability distribution of the solids particles penetration into the spout, fraction of cycle time in each region of the bed, the radial profiles of the dimensionless values of the root-mean-square particle velocities and solids eddy diffusivity. Finally, the results further advance the knowledge and understanding of the gas-solids spouted beds provide deeper insight into their solids dynamics and presenting important benchmarking data for validating computational fluid dynamics codes and models. At last, procedures are established for the implementation of the new scale-up methodology.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2023

In situ high-temperature 3D imaging of the damage evolution in a SiC nuclear fuel cladding material

Silicon carbide (SiC)-based nuclear fission fuel rod cladding has been considered as one of the possible designs for accident tolerant fuels. It is in the form of a SiC fibre reinforced SiC matrix composite tube (SiC f -SiC m ) with monolithic SiC outer and/or inner coating layers. This study focuses on the deformation and fracture processes in this material using in situ X-ray micro-computed tomography (XCT) at room temperature (RT) and 1200 °C in an inert gas environment in a C-ring compression loading configuration. Prior to testing, local properties and residual stresses were characterised using nanoindentation and Raman spectroscopy since they can impact the mechanical behaviour of the material. The 3D strain distribution, crack formation and propagation processes including the toughening mechanisms (e.g., crack deflection, micro-cracking, crack bridging and bifurcation) are investigated in the coating and underlying composites at RT and 1200 °C. There is no particular sequence which toughening mechanism occurs first – this is very different from the conventional toughening theory in ceramic-matrix composites under uniaxial tension loading. Indeed, no evidence of fibre pull-out or fibre fracture was observed in this SiC f -SiC m nuclear cladding material in the current C-ring compression configuration. The correlation between local measurements and bulk mechanical behaviour are discussed.

3D imaging↗
DOE OSTI2023

Ion and Hydrodynamic Translucency in 1D van der Waals Heterostructured Boron-Nitride Single-Walled Carbon Nanotubes

An unresolved challenge in nanofluidics is tuning ion selectivity and hydrodynamic transport in pores, particularly for those with diameters larger than a nanometer. In contrast to conventional strategies that focus on changing surface functionalization or confinement degree by varying the radial dimension of the pores, we explore a unique approach for manipulating ion selectivity and hydrodynamic flow enhancement by externally coating single-walled carbon nanotubes (SWCNTs) with a few layers of hexagonal boron nitride (h-BN). Here, for van der Waals heterostructured BN-SWCNTs, we observed a 9-fold increase in cation selectivity for K + versus Cl – compared to pristine SWCNTs of the same 2.2 nm diameter, while hydrodynamic slip lengths decreased by more than an order of magnitude. These results suggest that the single-layer graphene inner surface may be translucent to charge-regulation and hydrodynamic-slip effects arising from h-BN on the outside of the SWCNT. Such 1D heterostructures could serve as synthetic platforms with tunable properties for exploring distinct nanofluidic phenomena and their potential applications.

36 MATERIALS SCIENCE↗
DOE OSTI2023

A fluorinated cation introduces new interphasial chemistries to enable high-voltage lithium metal batteries

Abstract Fluorides have been identified as a key ingredient in interphases supporting aggressive battery chemistries. While the precursor for these fluorides must be pre-stored in electrolyte components and only delivered at extreme potentials, the chemical source of fluorine so far has been confined to either negatively-charge anions or fluorinated molecules, whose presence in the inner-Helmholtz layer of electrodes, and consequently their contribution to the interphasial chemistry, is restricted. To pre-store fluorine source on positive-charged species, here we show a cation that carries fluorine in its structure is synthesized and its contribution to interphasial chemistry is explored for the very first time. An electrolyte carrying fluorine in both cation and anion brings unprecedented interphasial chemistries that translate into superior battery performance of a lithium-metal battery, including high Coulombic efficiency of up to 99.98%, and Li 0 -dendrite prevention for 900 hours. The significance of this fluorinated cation undoubtedly extends to other advanced battery systems beyond lithium, all of which universally require kinetic protection of highly fluorinated interphases.

25 ENERGY STORAGE↗
DOE OSTI2020

Unveiling the mechanisms of lithium dendrite suppression by cationic polymer film induced solid–electrolyte interphase modification

It is crucial to suppress lithium dendrite formation in lithium metal batteries. Formation of a good solid–electrolyte interphase (SEI) has been considered to be effective in limiting lithium dendrite growth. However, how the SEI may be modified during lithium deposition is hard to resolve due to challenges in in situ investigation of the SEI with fine details. Here, we report an in situ study that uncovers the lithium dendrite suppression mechanism arising from SEI modification by a poly(diallyldimethylammonium chloride) (PDDA) cationic polymer film, using electrochemical liquid cell transmission electron microscopy (TEM). Lithium nanogranules are obtained in the presence of the polymer film. Chemical mapping of the deposits provides remarkable details of the SEI on individual nanogranules. It shows that lithium fluorides are uniformly distributed within the inner SEI layer of individual lithium nanogranules, arising from the instantaneous reaction of the deposited lithium with PF 6 – ions accumulated by the cationic polymer film, and thus the dendritic growth of lithium is prohibited. The ability to directly measure SEI chemistry at the nanoscale down to the individual nanograins in situ and unveil its correlation with the lithium deposition behavior opens future opportunities to explore unsolved mechanisms in batteries.

25 ENERGY STORAGE↗
DOE OSTI2023

Characterization of a Novel CD4 Mimetic Compound YIR-821 against HIV-1 Clinical Isolates

Small CD4-mimetic compound (CD4mc), which inhibits the interaction between gp120 with CD4, acts as an entry inhibitor and induces structural changes in the HIV-1 envelope glycoprotein trimer (Env) through its insertion within the Phe43 cavity of gp120. Here, we recently developed YIR-821, a novel CD4mc, that has potent antiviral activity and lower toxicity than the prototype NBD-556. To assess the possibility of clinical application of YIR-821, we tested its antiviral activity using a panel of HIV-1 pseudoviruses from different subtypes. YIR-821 displayed entry inhibitor activity against 53.5% (21/40) of the pseudoviruses tested and enhanced neutralization mediated by coreceptor binding site (CoRBS) antibodies in 50% (16/32) of these. Furthermore, when we assessed the antiviral effects using a panel of pseudoviruses and autologous plasma IgG, enhancement of antibody-mediated neutralization activity was observed for 48% (15/31) of subtype B strains and 51% (28/55) of non-B strains. The direct antiviral activity of YIR-821 as an entry inhibitor was observed in 53% of both subtype B (27/51) and non-B subtype (40/75) pseudoviruses. Enhancement of antibody-dependent cellular cytotoxicity was also observed with YIR-821 for all six selected clinical isolates, as well as for the transmitted/founder (T/F) CH58 virus-infected cells. The sequence diversity in the CD4 binding site as well as other regions, such as the gp120 inner domain layers or gp41, may be involved in the multiple mechanisms related to the sensitive/resistant phenotype of the virus to YIR-821. Our findings may facilitate the clinical application of YIR-821.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

Searches for New Long-Lived Particles and Upgrade to the ATLAS Inner Detector (Final Technical Report)

The search for new fundamental particles is one of the defining goals of the Large Hadron Collider (LHC). The discovery of the Higgs Boson by the ATLAS and CMS collaborations provided the capstone of the Standard Model of particle physics, but outstanding questions remain. Why does the Higgs boson have a mass of 125 GeV when its natural mass would be many orders of magnitude larger? Is there a universal symmetry which unites all three forces described by the Standard Model? Can that symmetry be extended to include gravity? Is dark matter, evidenced by astronomical observations, made of a particle that interacts via Standard Model forces with the rest of matter? Together, these motivations provide compelling arguments that new physical processes await discovery. This project addressed some outstanding questions about the fundamental particles and their interactions with the ATLAS experiment at the Large Hadron Collider. In particular, the project improved the discovery potential for new, long- lived particles produced via electroweak processes in proton-proton collisions and set world-leading limits on their existence for certain values of their potential mass and lifetime. To achieve this, the project developed new data analysis methods, developed new triggers to select events with new long-lived particles during data-taking of the ATLAS experiment, and analyzed the largest proton–proton collision dataset ever produced. The project also supported significant development of the data acquisition software for the upgrade to the ATLAS inner detector, the Inner TracKer (ITk). The upgrade of the ATLAS inner detector is essential to the success of the entire Phase II physics program on ATLAS. Personnel supported by the project provided support for integration, assembly, and testing of the inner two layers of the ITk pixel system during its prototype and pre-production phase. Four PhD students and two post-doctoral scholars were supported by the grant and received invaluable scientific training as part of the research endeavor. The students and postdocs gained essential professional skills in the areas of advanced data analysis techniques, statistical analysis of data and simulation, programming in C++ and Python, hardware and instrumentation development, and presentation and collaboration skills. Additionally, approximately ten undergraduate students supported through other funding sources participated in research activities synergistic with the goals of this project, receiving essential mentorship from the personnel supported by this project.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

A pixel detector ROIC with a 3-bit, 40 Msps synchronous ADC per pixel for HL LHC

The prototype Fermi Compact Muon Solenoid (CMS) Pixel (FCP130), manufactured in a 130 nm process, is a readout integrated circuit (ROIC) designed for the High Luminosity upgrade of the Large Hadron Collider. It employs a synchronous analog to digital converter (ADC) for the front-end design, with signal processing and data conversion within a single bunch crossing of 25 ns. It is therefore capable of accurately detecting hits occurring in consecutive bunch crossings, without off-time registration of events, making it particularly suitable for the inner most layers of the vertex detector. The ROIC consists of a matrix of 48 × 160 pixels, each 100 × 30 μm2 in size. Each pixel contains a charge sensitive preamplifier with self-biasing leakage current compensation, eight auto-zero comparators and a Gray code encoder for a 3-bit flash-type ADC. The total power consumption is approximately 24 μW per pixel. The measured noise at the output of all the hit comparators across the ROIC is < 80 e- with threshold dispersion < 110 e-RMS, which allows an in-time threshold setting of ~ 1000 e-.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

AGR-5/6/7 Irradiation As Run Predictions Using PARFUME

The PARticle FUel ModEl (PARFUME), a fuel performance modeling code used for high-temperature gas-cooled reactors, was used to model the Advanced Gas Reactor (AGR)-5/6/7 irradiation test using as-run physics and thermal data. The AGR-5/6/7 irradiation test consists of the combined fifth, sixth, and seventh planned irradiations of the AGR Fuel Development and Qualification Program. The AGR-5/6/7 test train is a multi-capsule, instrumented experiment that is designed for irradiation in the 133.4-mm diameter northeast flux trap position of the Advanced Test Reactor (ATR) at Idaho National Laboratory. Each capsule contains compacts filled with uranium oxycarbide unaltered fuel particles. This report documents the calculations performed to predict the failure probability of tristructural isotropic (TRISO)-coated fuel particles during the AGR-5/6/7 experiment. In addition, this report documents the calculated fission product release fraction from the fuel. The calculations include modeling of the AGR 5/6/7 irradiation that occurred from February 2018 to July 2020 over nine ATR cycles, including six normal cycles and three power axial locator mechanism cycles, for a total of approximately 376 effective full power days (EFPD). The irradiation conditions and material properties of the AGR-5/6/7 test predicted zero fuel particle failures in Capsules 1, 3, and 4. Fuel particle failures were predicted in two of the compacts in Capsule 2 and one particle failure is predicted in each one of the compacts in Capsule 5. All compacts that exhibited fuel particle failures predicted by PARFUME were caused by localized stress concentrations in the silicon carbide (SiC) layer caused by cracking in the inner pyrolytic (IPyC) layer. In addition, shrinkage of the buffer and IPyC layer during irradiation resulted in formation of a buffer-IPyC gap. Compacts with a lower irradiation temperature and fluence experienced the smallest buffer-IPyC gap formation. Conversely, higher irradiated temperature compacts with a high fluence experienced the largest buffer-IPyC gap formation. Compact 3-6-3 experienced the largest buffer IPyC gap formation of just under 21.7 µm. The release fraction of fission products silver (Ag), cesium (Cs), and strontium (Sr) vary depending on capsule location and irradiation temperature. The maximum release fraction of Ag occurs in Capsule 3, reaching up to 59.5% for the TRISO fuel particles (compact 3-6-3). The release fraction of the other two fission products, Cs and Sr, are much smaller. A maximum Cs release fraction of 1.1% occurred in compact 3-4-3 and 4.4% for Sr in compact 3-6-3.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

In-Pixel Readout IC with compact in-pixel ADC for Pixel detectors at HL LHC

The prototype Smart Pixel concept test chip (SP28), designed in a CMOS 28 nm bulk process, is a proof of concept readout integrated circuit (ROIC) designed for a future Phase III High Luminosity upgrade of the Large Hadron Collider. It employs a synchronous analog to digital converter (ADC) for the front-end design, with signal processing and data conversion within a single bunch crossing of 25 ns. It is therefore capable of accurately detecting hits occurring in consecutive bunch crossings, without off-time registration of events and pileup insensitivity, making it particularly suitable for the inner most layers of the vertex detector. The ROIC consists of a matrix of 32 × 16 pixels, each 25 × 25 µm 2 in size. Each pixel contains a charge sensitive preamplifer with leakage current compensation, three auto-zero comparators for a 2-bit fash-type ADC. The total power consumption is approximately 5 µW per pixel. The measured noise at the output of all the hit comparators across the ROIC is < 90 e- with threshold dispersion < 45 e-RMS, which allows an in-time threshold setting of ≈ 475 e-.

Parpillon, Benjamin↗
DOE OSTI2020

First Field Measurements of the 15 T Nb 3 Sn Dipole Demonstrator MDPCT1

Within the US Magnet Development Program (MDP) a 15 T Nb 3 Sn dipole was developed, to demonstrate a magnet design for a post-LHC pp Collider. Specifically, the magnet design is based on 60 mm aperture 4-layer shell-type coils, graded between the inner and outer layers to maximize the magnet performance. The cable in the two innermost layers has 28 strands 1.0 mm in diameter and the cable in the two outermost layers has 40 strands 0.7 mm in diameter. Both cables use RRP Nb3Sn wires produced by Bruker-OST. Magnet coils are surrounded by vertically-split thick iron laminations, con-nected by aluminum I-clamps, and a thick stainless-steel skin. The magnet was tested at the Vertical Magnet Test Facility (VMTF) at Fermilab. This paper reports the first results of magnetic measure-ments of the 15 T Nb 3 Sn dipole demonstrator including geometrical harmonics, coil magnetization and iron saturation effects. The ex-perimental data are compared with the magnetic calculations.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Expanding the Cage of 2D Bromide Perovskites by Large A-Site Cations

Two-dimensional (2D) halide perovskites have outstanding optoelectronic properties, and they feature a variety of organic cation spacers and cage A-site cations that can be incorporated into their structures. It has recently been reported that the Goldschmidt tolerance factor can be relaxed and expanded in iodide 2D perovskites. Bromide 2D perovskites, whose multilayer structures and optical properties are much less studied, provide a great platform for studying structure-property relationships for 2D perovskites with large Asite cations. Herein, we report the synthesis and structure of three new 2D bromide perovskites-(BA)(2)(MHy)(2)Pb3Br10 (BA, butylammonium; MHy, methylhydrazinium), (BA)(2)(EA)(2)Pb3Br10 (EA is ethylammonium), and (BA)(2)(DMA)Pb2Br7 (DMA is dimethylammonium). We compared them with other 2D perovskites with different A-site cations but with the same spacer and layer thickness. Single-crystal structures show that the Pb-Br bonds are elongated to accommodate the large A-site cations. Additionally, the octahedra in (BA)(2)(MHy)(2)Pb3Br10 and (BA)(2)(EA)(2)Pb3Br10 are highly distorted, and their different stacking patterns of the inner and outer layers lead to the formation of the n = 3 phases. Density functional theory calculations show that 2D perovskites with larger A-site cations (e.g., DMA, MHy, and EA) have smaller band dispersions and larger effective masses than those with Cs+ and MA. (BA)(2)(MHy)(2)Pb3Br10 also exhibits one of the largest Rashba splittings in the literature. Structures with large cage cations also exhibit high band gaps within the same n number and short photoluminescence (PL) lifetimes. Temperature- and power-dependent PL measurements reveal that the broad shoulder in the PL peak originates from the trap states.

Emission↗
DOE OSTI2022

Methods and systems for treatment of superconducting materials to improve low field performance

A system and method for treating a cavity comprises preparing a superconducting radio frequency (SRF) cavity for removal of a dielectric layer from on an inner surface of the SRF cavity, subjecting the SRF cavity to a heat treatment in order to remove the dielectric layer from the inner surface of the SRF cavity, and preventing the development of a new dielectric layer on the inner surface of the SRF cavity by preventing an interaction between the inner surface of the SRF cavity and atmospheric gasses.

Romanenko, Alexander↗
DOE OSTI2022

Microstructure of irradiated AGR TRISO particle buffer layers as measured by X-ray computed tomography

Shrinkage of the initially low-density buffer layer in tristructural isotropic (TRISO) coated fuel particles during irradiation is a well-known phenomenon with potential implications for fission product and actinide transport, as well as potential pyrocarbon fracture that in some cases has been observed to impact particle performance. During post-irradiation examination, the buffer layer's structure is commonly determined using 2D microscopy of a particle cross section or a series of particle cross sections at staggered depths. Although these methods provide a general idea of the irradiated buffer microstructure, they do not provide a full picture of the TRISO coating microstructure. By contrast, x-ray computed tomography (XCT) provides full 3D imaging of the TRISO particle. Particles from various compacts irradiated for the Advanced Gas Reactor Fuel Development and Qualification Program were imaged using XCT. Some of these particles were selected because of abnormal fission product inventories (e.g., low 137 Cs), whereas others were randomly selected from the center of the fission product inventory distribution. Qualitative and quantitative analysis techniques were applied to the randomly selected particles as representatives of typical TRISO behavior to study the post-irradiation structure of the buffer layer. These results showed that, while separation of the buffer and inner pyrolytic carbon layers was a common behavior during the radiation-induced shrinkage of the buffer, a portion of the original buffer/inner pyrolytic carbon interface remained intact throughout irradiation in nearly all cases. Furthermore, these results also indicated clear trends in the degree of buffer densification with irradiation temperature and fluence.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Field Measurement Results of the 15 T Nb 3 Sn Dipole Demonstrator MDPCT1b

A 15 T Nb 3 Sn dipole with cos-theta-type coils was developed to demonstrate a possible magnet design for a post-LHC proton-proton Collider. The magnet has 4-layer coils with 60-mm aperture, and has graded current density between the inner and outer layers to maximize performance. The coils are constrained by vertically-split, thick iron laminations, connected by aluminum Iclamps, and a thick stainless-steel skin. The magnet was previously tested at the Vertical Magnet Test Facility (VMTF) at Fermilab with reduced pre-load, and achieved record 14.1 T fields at maximum current. Now the magnet has been reassembled with full pre-load and has been cryogenically retested at VMTF. We report here on the magnetic measurements results of these tests, including field strength, geometrical harmonics, coil magnetization, and iron saturation characteristics of the demonstrator.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Development and Test of a Large Aperture $Nb_3Sn$ Cos-Theta Dipole Coil with Stress Management

An innovative stress-management (SM) concept for cos-theta (CT) coils (SMCT coil concept) has been proposed at Fermilab. A large-aperture two-layer Nb3Sn SMCT dipole coil was designed and manufactured to validate and test the SM concept including coil design, fabrication technology, and performance. The first large-aperture SMCT coil (SMCT1) was fabricated and assembled with a small-aperture Nb3Sn coil inside a dipole mirror magnet. SMCT1 coil tests in a dipole mirror structure was performed in two configurations - SMCTM1a with only powered two-layer SMCT1 coil and SMCTM1b with the SMCT coil connected in series with an inner two-layer dipole coil. The test goals are to prove the SMCT coil concept in two-layer and four-layer mirror configurations; demonstrate that the magnet can reach the targeted quench current at the established preload; study magnet training, training memory after thermal cycle, ramp rate and temperature dependences of the magnet quench current; and test the SMCT1 coil quench protection parameters. This paper summarizes the SMCT1 coil design and parameters, the coil main fabrication steps, its assembly in the dipole mirror structure. The results of the SMCTM1a/b mirror test are presented and discussed.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Validating methods for modeling composition gradients in planar shock experiments

An interface is Rayleigh–Taylor (RT) unstable when acceleration pushes a less dense material into a more dense one, and the growth of the instability is governed partly by the Atwood number gradient. Double-shell inertial confinement fusion capsules have a foam spacer layer pushing on an inner capsule composed of a beryllium tamper and high-Z inner shell, and so have RT unstable interfaces that require benchmarking. To this end, the results of a planar shock experiment with beryllium/tungsten targets are presented. One target had the normal bilayer construction of beryllium and tungsten in two distinct layers; the second target had the beryllium grading into tungsten with a quasi-exponential profile, motivated by the potential for reduced RT growth with the gradient profile. Simulations mimic the shock profiles for both targets and match the shock velocity to within 5%. These results validate the ability of our simulations to model double-shell capsules with bilayer or graded layer Be/W inner shells, which are needed to design future experiments at the National Ignition Facility.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗