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At least 379 records · Page 21

University Pipeline (with UNM) for Criticality Safety Professionals [Slides]

The scope of the University Pipeline is to provide students with knowledge of NCS and to inspire students to pursue a career in NCS after graduation. There are several benefits of the University Pipeline: reduced training time and costs; interested students that naturally self-sort and pursue the discipline at the university level; and a pipeline of criticality safety candidates readily available within the DOE Complex so that unexpected organizational or mission changes can be reacted to with increased agility.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

CRADA Number NFE-18-07313 with Nth Cycle, Inc. (CRADA Final Report)

Cooperative Research and Development Agreement (CRADA) NFE-18-07313 between Oak Ridge National Laboratory (ORNL) and Nth Cycle Inc. focused on developing a technology for sustainable recycling of rare earth and specialty metals (e.g., Y, Co, Li; RESE), as well as bulk and precious metals from industrial manufacturing and waste streams through the use of electrochemical carbon nanotube-enabled filters. The project outcome was expected to be a stronger mechanistic understanding of the electrochemical recovery of metals from real manufacturing process streams and e-waste streams, and the development of an optimized high-throughput pilot-scale device ready for commercialization. Testing, design, and development of a v1 prototype to prove the technology was unsuccessful (we were not able to reach the go/no-go outlined in Objective 1) and we were unable to continue our redesign due to COVID-19 lockdown and no access to lab from March 2020 – until our graduation from the program.

36 MATERIALS SCIENCE↗

Theoretical Particle Physics in the Data-Driven Era (Final Report)

DOE award DE-SC0021447 supports theoretical research in high energy physics. PI and students are not a part of any experimental collaboration, even if some works were done in collaboration with experimental colleagues. All research products are in the form of research articles and they are publicly available under inspirehep.net and arxiv.org, which are typical publication methods in high energy physics. No invention or patent is involved with this research. No equipment or hardware is involved with the research under this award. Research outcomes are used by colleagues in high energy physics, including both theorists and experimentalists. Therefore the outcome of research topics under this award supported the High Energy Physics experimental research program, both in understanding the data and in finding new directions for experimental exploration. The research materials are used to train undergraduate students, graduate students and postdoctoral scholars. We summarize research activity under this award in the following section and major products are listed in section 3. Section 4 contains professional presentations given by PI. Other products developed during the award period are in section 5. Students’ activities are summarized in section 6.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

High Temperature Optocoupler for 3D High Density Power Modules

The goal of this proposed research is to develop a reliable high-temperature optocouplers, which can operate at 250°C with at least ten-year lifetime, and replace isolation transforms as the galvanic isolation solution for the 3D integration of high density power modules. The electrification of future transportations (i.e., electric vehicles) will continuously drive the demand for high density power modules. Optocouplers (i.e., packaged light emitter and detector) as a promising candidate to replace bulky isolation transformers are highly desirable to facilitate the continuous scale-down of gate driver circuitry that will lead to 3D high density power modules and achieve disruptive performance in terms of thermal management, power density, power efficiency, reliability and operating environments. However, regular semiconductor optoelectronic materials and devices have significant difficulty functioning in the harsh environments designated for high density power module usage (such as operation at high temperatures). Ultimately, it is not the intrinsic properties of power devices that prevent their use at higher temperatures, but rather the low voltage electronics needed to drive them and the packaging that surrounds them. The typical operating temperature for optocouplers is only up to 100°C, due to the limitations of light emitting diode (LED) devices inside and packaging materials. A systematic characterization methodology will be developed to analyze the performance, lifetime and reliability of LED devices and distinguish multiple failure mechanisms at high temperatures. An original methodology of “design for reliability” will be developed to design the optoelectronic devices with high reliability and long lifetime at high temperatures. A new architecture of high temperature high reliable optocouplers will be developed, fabricated and demonstrated with continuous operating at 250°C. The development of efficient, reliable high density 3D power modules is the foundation for energy efficiency and energy reliability. Enabled with advanced 3D integration and packaging technologies, high density power module solutions can achieve much more superior performance over the conventional discrete solutions in terms of efficiency, thermal management and power density. The proposed concept of high temperature optocouplers as the galvanic isolation solution for high density power modules will bring together interdisciplinary research involving the wide bandgap materials, optoelectronics, high reliable device design, electronics packaging and power modules. A streamline of skilled personnel would be trained including graduate and undergraduate students, local engineers and scientists which are in great demand to both academia and optoelectronics industry. The proposed research topics, such as, solid state lighting and high temperature device reliability, are currently of major interest at the Department of Energy, in particular, Sandia National Laboratories. This project can enhance collaborations between the University of Arkansas (UA) and Sandia National Laboratories. The findings of the proposed research are expected to be integrated into high density 3-D power modules at the Engineering Research Center for Power Optimization for Electro-Thermal Systems (POETS).

42 ENGINEERING↗

Quasi-static to Dynamic Response and Microstructure Development of Tantalum-Tungsten Alloys

Lawrence Livermore National Laboratory (LLNL) has a need to understand the quasi-static to dynamic mechanical response and microstructure evolution of tantalum-tungsten (Ta-W) alloys made by conventional wrought processing and additive manufacturing (AM). This two-year work scope will be performed at the Colorado School of Mines (Mines) and will include quasi-static (e.g., 10 -3 s -1 ) mechanical testing in tension and compression, along with high strain rate (Kolsky) pressure bar testing in tension and compression (e.g., 10 3 s -1 ), without and with temperature variations. Gas gun experiments at higher strain rates (e.g., over 10 3 s -1 ) will also be pursued. Complementary microstructure characterization will be performed on undeformed and deformed samples to fundamentally understand the role of processing on the microstructure characteristics and resulting deformation mechanisms that dictate the mechanical response of these alloys with variations in strain rate, temperature, and strain state. Alloys of interest will be Ta-based, containing up to 10 wt.% W. LLNL will supply initial wrought-processed material for sample machining. LLNL will also supply samples built by AM during the project for testing. Arc melting and casting may also be performed at Mines to produce small quantities of different alloys for machining and exploratory testing on an as-needed basis. This project will support multiple postdocs and graduate students at Mines, training them with the knowledge, skills, and abilities needed to study materials under extreme conditions of interest to the National Nuclear Security Agency.

36 MATERIALS SCIENCE↗

MPA Materials Matter (Fall 2022)

The first cuprate high temperature superconductor was discovered when Leonardo Civale was a physics graduate student in Argentina. Fascinated, he abandoned his previous research to focus on these exotic materials—the existence of which challenged years of accepted knowledge—and he never strayed.

36 MATERIALS SCIENCE↗

X-ray Pump-Probe Measurements using a Laser-Plasma Accelerator (Final Report)

This project funded one graduate student, Mario Balcazar, to perform experiments on high power laser facilities to study the application of X-rays generated by laser wakefield accelerated electrons for advanced radiography, in particular X-ray phase contrast imaging of hydrodynamic shocks/instabilities. The work made use of the DOE’s LaserNetUS facilities. We performed dynamic phase-contrast X-ray imaging of the shock generated by a 200 ps duration laser pulse (E = 1 J, I = 10 15 Wcm –2 ) with a 30 µm diameter liquid target, with unprecedented spatio-temporal resolution. This includes multi-shock generation within the liquid jet and plasma instability formation. Innovative electron-beam radiography was used to probe the laser-plasma interplay finding evidence of bilateral heating of the water followed by strong electric field generation. These measurements help explain some of the discrepancies between simulation and experiment and pave the way to better plasma diagnostic systems in HED and ICF physics experiments. This work was performed in collaboration with researchers from Michigan, LLNL, LBL and Sandia National Laboratories, Queen’s University Belfast and Imperial College.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Neptunyl and Uranyl Peroxide Chemistry in Molten Salts, Uranyl Structures from Nature, and Thermodynamic Studies Extending into the Transuranium Elements (Final Report)

This project was initially funded in 2007 and the current technical report is for 2019-2022. The specific objectives of this project (2019-2022) were: (1) Synthesis of actinide peroxide compounds in molten salt eutectics, (2) Studies of new uranyl minerals with fascinating structures and compositions, (3) Drop-solution calorimetric studies of actinide compounds extending into the transuranium elements, with an emphasis on the uranyl-sulfate system, (4) Continuation of studies of uranyl vanadate clusters synthesized using ionic liquids, (5) The training of Ph.D. graduate students in actinide chemistry, and to introduce undergraduate students to actinide research through providing research assistantships and supervision. The report lists 67 archival journal papers describing the work, of which 23 were since 2019. Highlights of the work are summarized for the period 2019-2022.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Neutron Capture and Transmission Measurements of 54 Fe at the RPI LINAC [Slides]

Transmission and capture measurements provide a wholistic set of experimental data to start resonance evaluation on 54 Fe. Analysis thus far supports that changes are needed in 54 Fe evaluation. Major accomplishments include the completion of radiative capture measurements of 54 Fe and the completion of total cross section measurements of 54 Fe. Future work includes the completion of data analysis relevant to capture and transmission measurements (May 2022), complete fitting of new resonance parameters to 54 Fe data (early 2023), and completion of all required deliverables for graduation (May 2023).

07 ISOTOPE AND RADIATION SOURCES↗

2022 LLNL Nuclear Science and Security Summer Internship Program

The Lawrence Livermore National Laboratory (LLNL) Nuclear Science and Security Summer Internship Program (NS 3 IP) is designed to give graduate and undergraduate students an opportunity to come to LLNL for 8–10 weeks of hands-on research. Students conduct research under the supervision of a staff scientist, attend a weekly lecture series, interact with other students, and present their work to the LLNL scientific community at the end of the program. Students also have the opportunity to meet staff scientists one-on-one, participate in LLNL facility tours (e.g., the National Ignition Facility and Center for Accelerator Mass Spectrometry), and gain a better understanding of the various science programs at LLNL. Due to the travel and access restrictions imposed by the COVID-19 pandemic, the 2022 NS 3 IP was organized as a hybrid internship program. Five of the 20 NS 3 IP students participated remotely. One of the 8 students funded directly by DTRA participated remotely. With LLNL’s extensive institutional support, remote students accessed the laboratory’s cyberinfrastructure through a secure virtual desktop environment and all seminars, mentor interactions, summer presentations, and laboratory tours had a remote option. The hybrid approach to the internship program provided flexibility to both the interns and their mentors to construct creative research projects that maximized student exposure to nuclear science research that is relevant to DTRA and LLNL. We anticipate continuing a hybrid internship format in the summer of 2023.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

Exploratory Synthesis for Reactive f-Element Separations without Solvent

Solvent extraction is commonly used to separate different f-metals found in spent nuclear fuel, but this process results in large volumes of highly contaminated liquid waste that must be remediated or stored at significant expense. The project funded under this award was aimed at addressing solvent-related issues encountered in conventional f-metal separations. Our strategy focused on using solvent-free mechanochemical reactions to prepare lanthanide and actinide borohydride complexes so that they could be separated based on differences in their volatility. Key deliverables described in this report include proof-of-principle results demonstrating that borohydrides called aminodiboranates can be used for volatile lanthanide/lanthanide and lanthanide/uranium separations, as we proposed. Moreover, exploration of a closely related class of borohydrides called phosphinodiboranates allowed us to identify underlying chemical factors that control the volatility of trivalent lanthanide and uranium borohydride complexes with identical structures. Details of published and pending research products are provided, and these include comprehensive synthesis and characterization efforts required to support fundamental studies related to the proposed separations. These technical efforts supported the training of nine graduate students and three undergraduate researchers, and they established air-sensitive transuranic capabilities at the University of Iowa to enhance radiochemical workforce development.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Understanding and Controlling Turbulent Mixing in a Laboratory Magnetosphere

This report summarizes our most important recent research, building upon several years of productive research. This resulted in breakthroughs in our understanding of plasma confined by the strong field of a magnetic dipole, dissertations from several graduate students, and learning experiences from our undergraduate students.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Understanding and Controlling Turbulent Mixing in a Laboratory Magnetosphere

This report summarizes our most important recent re search, building upon several years of productive research. This resulted in breakthroughs in our understanding of plasma confined by the strong field of a magnetic dipole, dissertations from several graduate students, and learning experiences from our undergraduate students.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Reduced diffusion and enhanced retention of multiple radionuclides from pore structure characterization of barrier materials for enhanced repository performance

Fluid flow and chemical transport in porous media are the macroscopic consequences of pore structure, which integrates geometry (e.g., pore size and surface area, pore-size distribution) and topology (e.g., pore connectivity). Low-permeability geological media whose pores are poorly interconnected will exhibit the characteristics of anomalous diffusion and sample size-dependent effective porosity, which will strongly impact long-term net diffusion and retention of radionuclides in geological repository settings involving different host rocks and barrier materials. A suite of innovative and complementary experimental approaches is utilized to study the microscopic pore structure and macroscopic fluid flow & chemical transport for a range of host rocks and barrier materials, in addition to standard clay minerals and reference rocks. With a particular focus on quantifying the presence and magnitude of “isolated” pores for a reduced effective porosity in low-permeability geomedia, the integrated methodologies for basic properties and pore structure characterization of these geomedia include X-ray diffraction, thin section petrography, grain size distribution, water immersion porosimetry after vacuum-pulling for full saturation, mercury intrusion porosimetry, nitrogen physisorption, scanning electron microscopy, X-ray computed tomography, and (ultra-)small angle neutron (X-ray) scattering. In addition, custom-designed gas diffusion, tracer recipe involving a range of anionic and cationic chemicals with subsequent analyses by laser ablation and inductively coupled plasma-mass spectrometry, along with batch sorption, column transport, and imbibition tests were conducted for coupled effects of pore structure and chemical retention/transport. From the perspectives of pore structure in conjunction with multiple and complementary approaches to examining a range of sample sizes under different observational scales, we find that the poor pore connectivity is prevalent in low-permeability media (mudstone and crystalline rock) that is related to geological processes (e.g., compaction, diagenesis and thermal maturation). For example, the deep and organic matter-rich mudstones have a much smaller effective porosity than the total porosity (as a result of poor pore connectivity) and associated diffusion coefficient, and the effective porosity & diffusion coefficients are also dependent upon the sample sizes used in the measurement. Similarly, most of the pore space in the shallow mudstone is also controlled by pore-throat diameters in the 5-50 nm range of intergranular pore types from its fine-grained nature, but with an overall good pore connectivity. However, the nm-sized pore space (physically pore-network architecture) and strong sorption capacities (chemical retention from clay minerals) of both shallow and deep mudstones lead to the synergistic retention of cationic radionuclides and their utilities as effective host rocks and barrier materials. Our unique approaches of studying how the micro-scale pore structure affect macro-scale fluid flow, diffusion & retention, and chemical transport produce improved mechanistic understanding, and realistic quantification, of diffusion and retention of typical radionuclides in a range of generic host rocks and barrier materials (clay/shale, salt, crystalline rock, and tuff), with the overall results leading to scientifically-based understanding of enhanced isolation (from both diffusion and retention) of radionuclides and improved confidence on the long-term performance of geological repository to store high-level radioactive wastes. In addition to the training of 25 undergraduates, graduates, and postdocs of UTA, the scientists (organizations) involved in performing this work (e.g., discussion, sample sharing, and operation of SANS and SAXS instruments) include Ed Matteo, Yifeng Wang, and Kristopher Kuhlman (Sandia National Laboratories), Jens Birkholzer, Liange Zheng, Tim Kneafsey, and Sharon Borglin (Lawrence Berkeley National Laboratory), Mavrik Zavarin (Lawrence Livermore National Laboratory), Yukio Tachi and Yuta Fukatsu (Japan Atomic Energy Agency), Mieke de Craen (Euridice, Belgium), Markus Bleuel (NIST), Wei-Ren Chen, Gergely Nagy, Changwoo Do, William Heller, Larry Anovitz, and Kenneth Littrell (ORNL), as well as Jan Illvsky, Ivan Kuzmenko, Ju-Sang Park and Jon Almers (ANL). Key deliverables include a total of 13 peer-reviewed journal articles (nine published and three under review), 23 presentations at scientific conferences (AAPG, AAPG Southwest Section, AGU, Asian Clay Conference, GSA, GSA South-Central Section, IHLRWM, InterPore, International Conference on Chemistry and Migration Behavior of Actinides and Fission Products in the Geosphere, International Conference on Coupled Processes in Fractured Geological Media: Observation, Modeling and Application), and academic institutions (UTA, New Mexico State University; University of Poitiers, France; University of Helsinki, Finland; Uppsala University, Sweden; Istanbul Technical University, Turkey) and other organizations (Andra, France; Posiva Oy, Finland).

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Electronic Structure, Bonding and Reactivity in f-Element Chemistry (Final Technical Report)

The proposed research aims to further develop and apply advanced inorganic spectroscopic methods to f-element systems, including well-defined compounds, in-situ generated complexes (including potentially complex mixtures) and transient species. Our long term goal is to develop and apply advanced inorganic spectroscopic methods in f-element chemistry in order to advance our understanding of electronic structure, bonding and reactivity in f-element systems up to the level currently available for d-block systems. A further goal of our program is the training and development of graduate students in the application of advanced inorganic spectroscopic methods for the study of f-element systems, which is critically underdeveloped at US academic institutions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Production and Separations for High Specific Activity 186 Re, 189 Re and 47 Sc for Research and Clinical Applications: effective design of targets and recycling of targets and radioisotope separation

This grant involved three objectives for producing high specific activity radionuclides using reactor and accelerator technologies that would find use in medical, industrial and research applications. There was a strong emphasis in all projects to develop and train staff and students in all aspects of targetry, reactor and accelerator production, separation of radionuclides from enriched target material, and evaluating the specific activity of the product radionuclides. An additional objective was training of students (undergraduate, graduate, postdoctoral) in all aspects of radiochemistry.

07 ISOTOPE AND RADIATION SOURCES↗

Tunable Laser-Plasma Amplifier (Final Report)

Exploration at the laser intensity frontier has always offered new avenues for physics and reaching beyond this frontier is a grand challenge. Present-day petawatt-class lasers provide focused intensities on target of 10 22 W/cm 2 , corresponding to electric fields of 200 TV/m, while laser-plasma amplification opens a route for focused intensities well above 10 23 W/cm 2 . Intensities in this range provide the ability to test quantum electrodynamics in the unexplored low-energy, strong-field regime where signatures for new physics may arise. The behavior of matter under such extraordinary conditions is a rich and fascinating subject, not only in its own right in fundamental plasma physics, but for the many potential applications that promise to enrich the natural sciences in the future, including compact electron-beam, ion-beam particle accelerators, and ultra-bright X-ray sources. Although laser systems are now under construction internationally to access intensities of 10 23 W/cm 2 , the current technologies used appear to be fundamentally limited to these intensities. The realization of intensities beyond 10 23 W/cm 2 using parametric amplification in plasmas promises a breakthrough in high-energy density physics. Parametric amplification using Raman scattering in a plasma could provide the enabling technology for the generation of ultra-high-power laser pulses, but a more complete understanding of the nonlinear optics of plasmas is required. There is a significant gap in well-diagnosed laser-plasma instability studies of nonlinear plasma-wave phenomena, which are critical to understand for future laser-plasma devices. To achieve an efficient laser-plasma amplifier, plasma waves must be driven to large amplitude where significant energy can be rapidly transferred from the pump to the seed over the pulse duration of the seed. Simulations suggest that this nonlinear pump depletion regime can be achieved in the “pi-pulse” amplification regime. While simulations show this optimal regime with efficient amplification, it has remained elusive in experiments and there is a growing consensus within the community that thermal effects and pump beam limitations prevent laser-plasma amplifiers from progressing through the linear regime into the nonlinear pump depletion regime. Previous experiments have been significantly limited by the laser power available at the necessary wavelengths for the seed laser; therefore, the amplification is required to start in the linear regime where it is sensitive to many deleterious effects. The enabling technology (currently unique to plasma-wave amplification in the world) at the University of Rochester is the ability to provide a seed pulse with sufficient power (4 mJ/100 fs seed) to immediately drive nonlinear plasma waves into the pi-pulse regime and to tune its wavelength to optimize the efficiency of energy transfer. This in combination with the state-of-the-art OMEGA heater beams providing multiple kilojoules in a nanosecond to sufficiently heat the plasma make this system distinct from previous studies. These heater beams will provide, for the first time in Raman amplification studies, a homogeneous electron temperature high enough to prevent pump beam propagation issues that have plagued previous experiments. These systems will provide a platform for driving electron-plasma waves into the nonlinear regime where pump depletion and pulse shortening are predicted to lead to high amplification efficiencies (>30%). The Team has made significant progress through prior support from DOE Fusion Energy Sciences [DOE Office of Science Award Number DE-SC0016253 (2016-2022)]. This includes twenty-two peer-reviewed manuscripts, one patent, ten contributed talks presented at international conferences, and research that was highlighted as invited talks at fifteen international conferences. The broader impacts of this research are evident in the support of early career scientists, two Ph.D. theses, four current graduate students, a Masters Project, two undergraduate researchers, and an underrepresented minority student hired through the California Alliance for Minority Participation who now works as a Research Engineer in the group. This research met all of the funded research objectives and the highlights from primary Raman amplification thrust of this work are discussed below and form the foundation for the proposed research.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Mechanistic Studies to Enable Aerobic Oxidation of C-H Bonds by Manganese Catalysts (Final Report)

The project Mechanistic Studies to Enable Aerobic Oxidation of C-H Bonds by Manganese Catalysts provided fundamental new insight into the factors affecting hydrocarbon oxidation reactions by manganese-oxo complexes. These insights stem from the development of a structure-function relationship, whereby particular molecular properties of manganese(IV)-oxo complexes were shown to correlate to their efficacy in hydrocarbon oxidation reactions. This work is important, as manganese oxidation catalysts have seen increasing use in synthetic transformations, including reactions relevant to the synthesis of pharmaceuticals and other value-added chemicals. The desirability of developing new manganese catalysts stems from the inexpensive nature and low toxicity of the metal manganese, which contrasts with the high cost and toxicity of many other metals. The work carried out by this project was disseminated to the scientific community in the form of 14 peer-reviewed publications and over twenty presentations. In addition, the research results were incorporated into graduate and undergraduate courses at the University of Kansas, providing additional means of dissemination.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗