A5075127575- Nuclear Materials and Properties
- Radioactive element chemistry and processing
- Nuclear materials and radiation effects
- Nuclear Physics and Applications
- Radioactive contamination and transfer
- Luminescence Properties of Advanced Materials
- Molten salt chemistry and electrochemical processes
- Additive Manufacturing Materials and Processes
- Nuclear reactor physics and engineering
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Condensed Matter Physics
- Ammonia Synthesis and Nitrogen Reduction
- Fusion materials and technologies
- Extraction and Separation Processes
- Advanced X-ray Imaging Techniques
- Ion-surface interactions and analysis
- Additive Manufacturing and 3D Printing Technologies
- Semiconductor materials and devices
- Advanced Photocatalysis Techniques
- Machine Learning in Materials Science
- Quantum, superfluid, helium dynamics
- Advanced materials and composites
- Radiation Detection and Scintillator Technologies
- Astronomical and nuclear sciences
- Lanthanide and Transition Metal Complexes
Lawrence Livermore National Laboratory
2016-2025
Lawrence Livermore National Security
2017-2018
Karlsruhe Institute of Technology
2012
University of Nevada, Las Vegas
2009-2011
California State University, San Marcos
2008
Density Functional Tight Binding (DFTB) is an attractive method for accelerated quantum simulations of condensed matter due to its enhanced computational efficiency over standard Theory approaches. However, DFTB models can be challenging determine individual systems interest, especially metallic and interfacial where different bonding arrangements lead significant changes in electronic states. In this regard, we have created a rapid-screening approach determining systematically improvable...
Hydrogel infused additive manufacturing (HIAM) is an emerging technique for the of ceramics and metals. Distinct from slurry- or powder-based techniques, a hydrogel scaffold obtained in the...
This study demonstrates the 100 g scale manufacture of a plutonium alloy that ages at an accelerated rate. The resulting six times faster than typical weapons-grade due to addition 238Pu. As major innovation, process involved using partial direct oxide reduction technique. method was achieved by developing new, complex geometry stirrer additive manufacturing reduce 238Pu and efficiently incorporate it into metal. material then purified molten salt extraction electrorefining before being...
Understanding plutonium’s interaction with metals is crucial for optimizing pyrochemical operations, nuclear fuel containment, and various actinide processing techniques. Traditionally, tantalum crucibles are employed plutonium due to their high durability, excellent temperature stability, low solubility in plutonium. However, faces challenges such as wetting diffusion, making surface coatings particularly important applications enhance corrosion resistance against Tantalum also expensive...
One of the most toxic byproducts nuclear power and weapons production is transuranics, which have a high radiotoxicity long biological half-life due to their tendency accumulate in skeletal system. This accumulation inhomogeneous has been associated with chemical properties structure bone material rather than its location or function. suggests driving force incorporation requires an atomic scale mechanistic understanding process. Here we propose new mechanism for trivalent actinides...
This work presents the results for identification of chemical phases obtained by several laboratories as a part an international nuclear forensic round-robin exercise. In this powder X-ray diffraction (p-XRD) is regarded reference technique. Neutron produced superior high-angle pattern relative to p-XRD. Requiring only small amounts sample, µ-Raman spectroscopy was used first time in context potentially complementary technique The were identified pure UO2 two materials, and mixture UO2, U3O8...
Uranium metal is associated with several aspects of nuclear technology; it used as fuel for research and power reactors, targets medical isotope productions, explosive weapons precursors in synthetic chemistry. The study uranium at the laboratory scale presents opportunity to evaluate metallic fuels, develop new methods spent reprocessing advance science relevant forensics production. Since its first isolation 1841, from reaction chloride potassium metal, has been prepared by solid-state...
Nuclear weapons testing generates large volumes of glassy materials that influence the transport dispersed actinides in environment and may carry information on composition detonated device. We determine oxidation state U Fe (which is known to buffer actinide elements affect redox groundwater) samples melt glass collected from three U.S. nuclear tests. For selected samples, we also coordination geometry Fe, report Pu one sample. find significant variations among and, particular, a clear...
We have investigated the behavior of uranium dioxide (UO2) under high static pressure using a combination experimental and theoretical techniques. made Raman spectroscopic measurements up to 87 GPa, electrical transport 50 GPa from 10 K room temperature, optical transmission 28 GPa. also carried out calculations within GGA + U framework. find that frequencies match large extent, predictions for cotunnite (Pnma) structure above 30 but at higher pressures some is not captured theoretically....
The production of ceramics from uranium coordination compounds can be achieved through thermal processing if an excess amount the desired atoms (i.e., C or N), reactive gaseous products (e.g., methane nitrogen oxide) is made available to metal core via decomposition/fragmentation surrounding ligand groups. Here, computational thermodynamic approaches were utilized identify temperatures necessary produce some starting compounds─UI4(TMEDA)2, UCl4(TMEDA)2, UCl3(pyridine)x, and UI3(pyridine)4....
The aim of this work is to assess the effect ligand strength, symmetry, and coordination number on solid solution formation trivalent actinides lanthanides in carbonate sulfate minerals. This particular importance radionuclide migration where such as Pu, Am, Cm are responsible for majority radiotoxicity after 1000 years. Time-resolved laser fluorescence spectroscopy was used study trace concentrations dopant ion interaction with mineral phase. expands previous aragonite gypsum it found that...
Producing gram quantities of uranium metal in a controlled manner by traditional methods is challenging due to the complex chemistry precursor material and extreme thermal requirements. In this article, novel approach reported that combines modeling an advanced experimental technique for extracting from uranium-containing compound. Using nitride as example, computational thermodynamic identified decomposition pathway convert at temperatures exceeding 2500 K under conditions rapid cooling. To...
The compound ${\mathrm{Sm}}_{2}{\mathrm{Co}}_{17}$ displays magnetic properties amenable to permanent magnet applications owing both the $3d$ electrons of Co and $4f$ Sm. long-standing description interactions between Sm ions implies a truly ferromagnetic configuration, but some recent calculations challenge this axiom, suggesting at least propensity for ferrimagnetic behavior. We have used high-pressure synchrotron x-ray techniques characterize structural reveal robust state. local moment...
In this study, the photoemission from U 4f7/2 and 4d5/2 states N6O45O45 N67O45V x-ray excited Auger transitions were measured for a range of uranium compounds. The data are presented in Wagner plots parameter is calculated to determine utility technique analysis materials. It was demonstrated that equal core-level shift assumption holds uranium. therefore possible quantify relative relaxation energies, found have localized core-hole shielding. position compounds within plot made it infer...
Synchrotron radiation spectromicroscopy provides a combination of submicron spatial resolution and chemical sensitivity that is well-suited to analysis heterogeneous nuclear materials. The physical characteristics determined by scanning transmission X-ray microscopy (STXM) are complementary information obtained from standard radiochemical methods. In addition, microscopic quantities radioactive material can be characterized rapidly STXM with minimal sample handling intrusion, especially in...