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DOE OSTI2025

Role of Accelerated Burnup Irradiation Testing in Support of Accelerated Fuel Qualification

Accelerated fuel qualification has gained attention as a means to reduce the time needed to realize new nuclear fuel concepts and expand the operating windows of existing fuel forms. A key component of this approach is accelerated burnup irradiation testing. Although the concept of accelerated burnup has been familiar to the community for many decades, the specifics about how the increasing fission rate may be used as a qualification tool have not yet been elucidated. The present work provides a vision of how accelerated fission rate testing can enable accelerated fuel qualification. Technology readiness levels (TRLs) are reintroduced to demarcate the stages of traditional fuel qualification, and accelerated fuel qualification is presented in this context. The critical steps needed to achieve each TRL are reframed within the context of modern nuclear materials research and development, as revolutionary fuel concepts are more common than previous eras. The practical impacts of accelerated fuel qualification approaches as applied to contemporary fuel qualification efforts are illustrated. Examples are given to illustrate how accelerated burnup irradiations are being used currently and could be applied in the future to support qualification and licensure. Finally, outstanding challenges in the application of accelerated burnup methods to nuclear fuel qualification are summarized, with priority placed on understanding how fission rate impacts diffusion, microstructure evolution, and other critical mechanisms that dictate fuel performance.

Accelerated fuel qualification↗

DOE OSTI2026

The origin of metallic conductivity in Pt 3 O 4 : a first principles study

The platinum oxide Pt 3 O 4 exhibits metallic conductivity even though it contains square-planar PtO4 units, which in related oxides such as PtO are usually associated with insulating behavior. To identify the electronic origin of this anomalous metallicity, we performed a comprehensive first-principles study using the PBE and r 2 SCAN functionals together with Hubbard U corrections and spin-orbit coupling (SOC). Structural benchmarks show that r 2 SCAN with SOC and a moderate U value (<4 eV) reproduces the experimental lattice constants and formation enthalpy, whereas larger U values (~8 eV) destabilize the cubic structure. Across all functionals and U values considered in this work, Pt 3 O 4 remains metallic. Analyses of the projected density of states, band structures, charge-density isosurfaces, and bonding characteristics demonstrate that the dominant contribution to the metallic character originates from delocalized Pt–O–Pt hybridized antibonding states at the Fermi level. Direct Pt–Pt interactions are present but contribute less strongly to the conductivity. Bader charge analysis reveals only weak Pt charge disproportionation, consistent with mixed Pt II /Pt III character, and a small charge-transfer energy that prevents localization of the Pt 5d electrons even at elevated U. In contrast, PtO develops a Mott or charge-transfer gap under modest U despite having the same PtO 4 coordination environment. These findings demonstrate that persistent Pt–O–Pt covalency is the primary driver of metallicity in Pt 3 O 4 and support the view that this phase can remain conductive under oxygen reduction and oxygen evolution reaction conditions in fuel cell and electrolyzer environments.

36 MATERIALS SCIENCE↗

DOE OSTI2026

INtegrated Fluid & paRticles simulatioN cOde (INF&RNO) v1.0

INF&RNO (INtegrated Fluid & paRticle simulation cOde) is a 2D cylindrical (r-z) code to model the interaction of short laser pulse(s) with an underdense plasma. The code is based on an envelope model for the laser field, and the action of the laser on the plasma is modeled with the time-averaged ponderomotive force approximation. The code features an improved laser envelope solver which enables an accurate description of the laser pulse evolution deep into depletion even at a reasonably low resolution.

Benedetti, Carlo [Lawrence Berkeley National Labor↗

DOE OSTI2025

Levelized cost and carbon intensity of solar hydrogen production via water splitting using a scalable and intrinsically safe photocatalytic Z-scheme raceway system

Generating hydrogen from local energy resources such as solar or wind would unlock a low-carbon energy carrier that could be used to reduce greenhouse gas emissions in sectors such as industry and transportation. Yet, the allocation of new or existing power generation solely to hydrogen production remains contentious due to disputes regarding emissions accounting. Photocatalytic (PC) hydrogen production technologies offer a unique solution, as hydrogen is produced directly from solar energy and water, without the need for electricity generation. However, cost projections for all photocatalytic designs to date have suggested that they are not cost competitive compared to conventional electrolysis systems manufactured at scale. Herein, we offer the first illustrative benchmark of cost and carbon intensity of hydrogen produced in a type 2 “Z-scheme” photocatalytic reactor design, which employs suspended semiconducting nanoconductor particles organized into two stacked volumes in a raceway design. The “Z-scheme” system utilizes two separate photoabsorber particles, tuned to drive either the hydrogen evolution reaction or the oxygen evolution reaction individually, connected via a reversible, charge transfer redox couple in solution. Furthermore, the results suggest a highly competitive and scalable technology, that justifies further experimental validation and prototyping in the field.

Carbon↗

NASA NTRS1987

Polymer crystal growth facility concept for Space Station laboratory module

Interest in materials processing in space began to evolve in the late 1950's through low gravity simulation and some experiments on Apollo flights. Encouraged by the early results and considerations of the likely behavior of liquids and solidification process in low-gravity gave the recognition that this environment might be useful for a variety of unique processes. This generated a number of experimental ideas and gave rise to the design and development of facilities that will perform the experiments in space vehicles. These include the evolution of apparatus leading to the development of facilities for processing of materials on Skylab and now for the Space Transportation System (STS). The U.S. module on Space Station (SS) is going to expand this unique laboratory environment with practically no constraint on materials processing activity. This will need technology advancement for the hardware that will be required in this era. This presentation discusses the current concept for the experimental facility which will be housed in the U.S. Laboratory module on the Space Station and will allow the growth of single crystals of polymeric and organic materials using the state-of-the-art growth techniques.

Mookherji, Tripty↗

NASA NTRS2002

Origins of Solar Systems Program

O'D. Alexander, Conel↗

NASA NTRS2003

Final Summary of Research Report to the National Aeronautics and Space Administration Origins of Solar Systems Program

The chondrites are aggregates of components (e.g. chondrules, chondrule rims and matrix) that formed in the nebula but, at present, there is no consensus on how any of these components formed or whether their formation produced or post dated the chemical fractionations between the chondrites. Chondrites are, at present, the most primitive Solar System objects available for laboratory study and the conditions under which their principle components formed would provide the most direct constraints for models of nebula formation and evolution. The conditions under which chondrules formed is of particular importance because, if their relative abundance in chondrites approximates that in the nebula, they are the products of one of the most energetic and pervasive processes that operated in the early Solar System. The goal of this proposal was to combine theoretical modeling with a comprehensive study of the elemental and isotopic compositions of the major components in unequilibrated ordinary chondrites (UOCs), with the aim of determining the conditions in the nebula at the time of their formation. The isotopes of volatile and moderately volatile elements should be particularly revealing of conditions during chondrule formation, as evaporation under most conditions would lead to isotopic mass fractionation. Modeling of chondrule and matrix formation requires the development of a kinetic model of evaporation and condensation, and calibration of this model against experiments. Cosmic spherules present an opportunity to test our evaporation models under flash heating conditions that would be difficult to simulate experimentally. However, there is surprisingly little known about the isotopic compositions of silicate cosmic spherules, and a number of questions need to be addressed. Is the range of compositions they exhibit due to evaporation? If they are, are the relative volatilities consistent with the models/experiments and are the isotopic fractionations consistent with Rayleigh conditions? For instance, do the alkalis and S evaporate prior to significant melting so that conditions did not meet the Rayleigh criteria of rapid diffusion? If so, their isotopic fractionation might be considerably suppressed. Could this mechanism of K loss apply to chondrule formation? The Fe isotopic fractionation during evaporation of silicates has not been measured, so cosmic spherules might provide a clue to whether FeO diffusion is fast enough to maintain Rayleigh conditions during evaporation. And so on.

O'D. Alexander, Conel↗

NASA NTRS2023

Relativistic Electron Beams Accelerated By an Interplanetary Shock

Context: Collisionless shock waves have long been considered to be among the most prolific particle accelerators in the universe. Shocks alter the plasma they propagate through, and often exhibit complex evolution across multiple scales. Interplanetary (IP) traveling shocks have been recorded in situ for over half a century and act as a natural laboratory for experimentally verifying various aspects of large-scale collisionless shocks. A fundamentally interesting problem in both heliophysics and astrophysics is the acceleration of electrons to relativistic energies (> 300 keV) by traveling shocks. Aims: The reason for an incomplete understanding of electron acceleration at IP shocks is due to scale-related challenges and a lack of instrumental capabilities. This Letter presents the first observations of field-aligned beams of relativistic electrons upstream of an IP shock, observed thanks to the instrumental capabilities of Solar Orbiter. This study presents the characteristics of the electron beams close to the source and contributes to the understanding of their acceleration mechanism. Methods: On 25 July 2022, Solar Orbiter encountered an IP shock at 0.98 AU. The shock was associated with an energetic storm particle event, which also featured upstream field-aligned relativistic electron beams observed 14 min prior to the actual shock crossing. The distance of the beam’s origin was investigated using a velocity dispersion analysis (VDA). Peak-intensity energy spectra were analyzed and compared with those obtained from a semi-analytical fast-Fermi acceleration model. Results: By leveraging Solar Orbiter’s high temporal resolution Energetic Particle Detector (EPD), we successfully showcase an IP shock’s ability to accelerate relativistic electron beams. Our proposed acceleration mechanism offers an explanation for the observed electron beam and its characteristics, while we also explore the potential contributions of more complex mechanisms.

acceleration of particles↗

NASA NTRS1995

Evolution of the solar wind acceleration region during 1990-1994

The single-station measurements of interplanetary scintillation (IPS) at 2 and 8 GHz have been made at the Kashima Space Research Center of the Communications Research Laboratory in the period from 1990 to 1994. These IPS data are used to study the radial distribution of solar wind velocity and density fluctuations near the sun (i.e. 10-70 Rs), and the long-term variation in these properties. The IPS co-spectrum technique is applied here to estimate the solar wind velocity. Derived velocities show that the solar wind gains a speed significantly in the radial range from 10 to 30 Rs (solar radii). which is much farther than the source surface of the thermally driven solar wind model. From the scintillation index analysis. it is found that the radial fall of density fluctuations is well described by the power-law function. A series of IPS observations reveals that a pronounced change in velocity and turbulence level for this radial range occurs at the polar region of the sun during 1990-1994. That is, the high speed wind and the reduced turbulence region develop there as the solar activity declines. On the other hand, little long-term variation is observed for the solar wind acceleration region at a low latitude. From the comparison with He 1O83 nm observations. it is demonstrated that the change of the solar wind structure is closely linked with the evolution of the coronal hole on the solar surface.

Tokumaru, M.↗

DOE OSTI2024

Surface Composition Impacts Selectivity of ZnTe Photocathodes in Photoelectrochemical CO 2 Reduction Reaction

Light-driven reduction of CO 2 into chemicals using a photoelectrochemical (PEC) approach is considered as a promising way to meet the carbon neutral target. The very top surface of the photoelectrode and semiconductor/electrolyte interface plays a pivotal role in defining the performance for PEC CO 2 reduction. However, such impact remains poorly understood. Here, we report an electrodeposition-annealing route for tailoring surface composition of ZnTe photocathodes. Our work demonstrates that a Zn-rich surface on the ZnTe photocathode is essential to impact the CO 2 reduction activity and selectivity. In particular, the Zn-rich surface not only facilitated the interfacial charge carrier transfer, but also acted as electrocatalyst for boosting carbon product selectivity and suppressing the hydrogen evolution reaction. This work provides a new avenue to optimize the photocathode, as well as improvement of the CO 2 RR performance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2025

Viral Dynamic Models During COVID‐19: Are We Ready for the Next Pandemic?

Mathematical models have been used for about 30 years to improve our understanding of virus-host interaction, in particular during chronic infections. During the COVID-19 pandemic, these models have been used to provide insights into the natural history of acute SARS-CoV-2 infection, optimize antiviral treatment strategies, understand factors associated with transmission, and optimize surveillance systems. The impact of modeling has been accelerated by the availability of unprecedented multidimensional immune data from animal and human systems, which enhanced partnerships between experimentalists and theorists and led to exciting new modeling and statistical developments. In this mini review, we examine the lessons learned from the COVID-19 pandemic and discuss the main insights provided by mathematical models of viral dynamics at the different stages of the outbreak. Although we focus on respiratory infection, we also consider the new areas for development in anticipation of future acute infections from new or reemerging pathogens.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2024

Cultivation of novel Atribacterota from oil well provides new insight into their diversity, ecology, and evolution in anoxic, carbon-rich environments

Background: The Atribacterota are widely distributed in the subsurface biosphere. Recently, the first Atribacterota isolate was described and the number of Atribacterota genome sequences retrieved from environmental samples has increased significantly; however, their diversity, physiology, ecology, and evolution remain poorly understood. Results: We report the isolation of the second member of Atribacterota, Thermatribacter velox gen. nov., sp. nov., within a new family Thermatribacteraceae fam. nov., and the short-term laboratory cultivation of a member of the JS1 lineage, Phoenicimicrobium oleiphilum HX-OS.bin.34 TS , both from a terrestrial oil reservoir. Physiological and metatranscriptomics analyses showed that Thermatribacter velox B11 T and Phoenicimicrobium oleiphilum HX-OS.bin.34 TS ferment sugars and n-alkanes, respectively, producing H 2 , CO 2 , and acetate as common products. Comparative genomics showed that all members of the Atribacterota lack a complete Wood-Ljungdahl Pathway (WLP), but that the Reductive Glycine Pathway (RGP) is widespread, indicating that the RGP, rather than WLP, is a central hub in Atribacterota metabolism. Ancestral character state reconstructions and phylogenetic analyses showed that key genes encoding the RGP (fdhA, fhs, folD, glyA, gcvT, gcvPAB, pdhD) and other central functions were gained independently in the two classes, Atribacteria (OP9) and Phoenicimicrobiia (JS1), after which they were inherited vertically; these genes included fumarate-adding enzymes (faeA; Phoenicimicrobiia only), the CODH/ACS complex (acsABCDE), and diverse hydrogenases (NiFe group 3b, 4b and FeFe group A3, C). Finally, we present genome-resolved community metabolic models showing the central roles of Atribacteria (OP9) and Phoenicimicrobiia (JS1) in acetate- and hydrocarbon-rich environments. Conclusion: Our findings expand the knowledge of the diversity, physiology, ecology, and evolution of the phylum Atribacterota. This study is a starting point for promoting more incisive studies of their syntrophic biology and may guide the rational design of strategies to cultivate them in the laboratory.

59 BASIC BIOLOGICAL SCIENCES↗

NASA NTRS1984

Final stages of transition to turbulence in plane channel flow

This paper involves a numerical simulation of the final stages of transition to turbulence in plane channel flow at a Reynolds number of 1500. Three-dimensional incompressible Navier-Stokes equations are numerically integrated to obtain the time evolution of two- and three-dimensional finite-amplitude disturbances. Computations are performed on the CYBER-203 vector processor for a 32 x 51 x 32 grid. Solutions indicate the existence of structures similar to those observed in the laboratory and characteristics of the various stages of transition that lead to final breakdown. In particular, evidence points to the formation of a upside-down-V-shaped vortex and the subsequent system of horseshoe vortices inclined to the main flow direction as the primary elements of transition. Details of the resulting flow field after breakdown indicate the evolution of streaklike formations found in turbulent flows. Although the flow field does approach a steady state (turbulent channel flow), the introduction of subgrid-scale terms seems necessary to obtain fully developed turbulence statistics.

Biringen, S.↗

NASA NTRS2016

Laboratory Analysis of Silicate Stardust Grains of Diverse Stellar Origins

Silicate dust is ubiquitous in a multitude of environments across the cosmos, including evolved oxygen-rich stars, interstellar space, protoplanetary disks, comets, and asteroids. The identification of bona fide silicate stardust grains in meteorites, interplanetary dust particles, micrometeorites, and dust returned from comet Wild 2 by the Stardust spacecraft has revolutionized the study of stars, interstellar space, and the history of dust in the Galaxy. These stardust grains have exotic isotopic compositions that are records of nucleosynthetic processes that occurred in the depths of their now extinct parent stars. Moreover, the chemical compositions and mineralogies of silicate stardust are consequences of the physical and chemical nature of the stellar condensation environment, as well as secondary alteration processes that can occur in interstellar space, the solar nebula, and on the asteroid or comet parent body in which they were incorporated. In this talk I will discuss our use of advanced nano-scale instrumentation in the laboratory to conduct coordinated isotopic, chemical, and mineralogical analyses of silicate stardust grains from AGB stars, supernovae, and novae. By analyzing the isotopic compositions of multiple elements in individual grains, we have been able to constrain their stellar sources, explore stellar nucleosynthetic and mixing processes, and Galactic chemical evolution. Through our mineralogical studies, we have found these presolar silicate grains to have wide-ranging chemical and mineral characteristics. This diversity is the result of primary condensation characteristics and in some cases secondary features imparted by alteration in space and in our Solar System. The laboratory analysis of actual samples of stars directly complements astronomical observations and astrophysical models and offers an unprecedented level of detail into the lifecycles of dust in the Galaxy.

Nguyen, Ann N.↗

DOE OSTI2025

Feedforward equilibrium trajectory optimization with GSPulse

One of the common tasks required for designing new plasma scenarios or evaluating capabilities of a tokamak is to design the desired equilibria using a Grad-Shafranov (GS) equilibrium solver. However, most standard equilibrium solvers are time-independent and do not include dynamic effects such as plasma current flux consumption, induced vessel currents, or voltage constraints. Another class of tools, plasma equilibrium evolution simulators, do include time-dependent effects. These are generally structured to solve the forward problem of evolving the plasma equilibrium given feedback-controlled voltages. In this work, we introduce GSPulse, a novel algorithm for equilibrium trajectory optimization, that is more akin to a pulse planner than a pulse simulator. GSPulse includes time-dependent effects and solves the inverse problem: given a user-specified set of target equilibrium shapes, as well as limits on the coil currents and voltages, the optimizer returns trajectories of the voltages, currents, and achievable equilibria. This task is useful for scoping performance of a tokamak and exploring the space of achievable pulses. The computed equilibria satisfy both Grad-Shafranov force balance and axisymmetric circuit dynamics. The optimization is performed by restructuring the free-boundary equilibrium evolution equations into a form where it is computationally efficient to optimize the entire dynamic sequence. GSPulse can solve for hundreds of equilibria simultaneously within a few minutes. GSPulse has been validated against NSTX-U and MAST-U experiments and against SPARC feedback control simulations, and is being used to perform scenario design for SPARC. The computed trajectories can be used as feedforward inputs that are connected to the feedback controller to inform and improve feedback performance. The code for GSPulse is available open-source at github.com/jwai-cfs/GSPulse_public.

equilibrium↗

DOE OSTI2025

Evolution of Mass Spectrometers for High m / z Biological Ion Formation, Transmission, Analysis and Detection: A Personal Perspective

Mass spectrometry (MS) has become an essential tool in virtually all academic, pharmaceutical, and biopharmaceutical analytical laboratories. The specialized and bespoke area of MS research and application of high m / z ion (> m / z 6000 and high mass, >150 kDa) formation, transmission, analysis, and detection is a relatively new area of focus for MS that has seen dramatic acceleration in interest over the last two decades. Herein we delve into this exciting aspect of MS, discussing how MS instrumentation has been refined and evolved for native-MS analysis. We cover the early groundbreaking experiments showing high m / z ion formation, transmission, and preservation of protein structure in the gas phase. Additionally, we discuss specific instrument optimizations and modifications that have advanced high m / z ion generation, transmission, analysis, and detection, contributing to the research area known as gas-phase structural biology. Native-MS sample introduction methods, emerging technologies, and future perspectives are also examined. Finally, we share personal opinions, observations, and experiences that are new to the community or previously unpublished.

collisions↗

NASA NTRS2010

Evolution of the Tropical Cyclone Integrated Data Exchange And Analysis System (TC-IDEAS)

The Tropical Cyclone Integrated Data Exchange and Analysis System (TC-IDEAS) is being jointly developed by the Jet Propulsion Laboratory (JPL) and the Marshall Space Flight Center (MSFC) as part of NASA's Hurricane Science Research Program. The long-term goal is to create a comprehensive tropical cyclone database of satellite and airborne observations, in-situ measurements and model simulations containing parameters that pertain to the thermodynamic and microphysical structure of the storms; the air-sea interaction processes; and the large-scale environment.

CloudSat↗

NASA NTRS2017

The Evolution of Planetary Protection Implementation on Mars Landed Missions

NASA has developed requirements dedicated to the prevention of forward and backward contamination during space exploration. Historically, international agreements provided guidelines to prevent contamination of the Moon and other celestial bodies, as well as the Earth (e.g., sample return missions). The UN Outer Space Treaty was established in 1967 and the Committee on Space Research (COSPAR) maintains a planetary protection policy complying with Article IX of this treaty. By avoiding forward contamination, the integrity of scientific exploration is preserved. Planetary Protection mission requirements are levied on missions to control contamination. These requirements are dependent on the science of the mission and on the celestial bodies encountered or targeted along the way. Consequently, categories are assigned to missions, and specific implementation plans are developed to meet the planetary protection requirements. NASA missions have evolved over time with increasingly more demanding scientific objectives and more complex flight systems to achieve those objectives and, thus, planetary protection methods and processes used for implementation have become much more intricate, complicated, and challenging. Here, we will portray the evolution of planetary protection implementation at JPL in several important areas throughout the course of NASA sponsored robotic Mars lander or rover missions, starting from Mars Pathfinder through the beginning of Mars 2020. Highlighted in the discussion will be process changes in planetary protection requirements development and flow down. Development and implementation of new and improved methods used in the reduction of spacecraft bioburden will be discussed as well as approaches and challenges that come along with setting up remote laboratories to perform bioassays. The consequences and forward planning of delays on missions will be highlighted as well as lessons learned on the impact of communication and training in achieving planetary protection requirements. The evolution of methods used for the detection of microbial bioburden on spacecraft hardware will be considered. These methods use standard microbiology as well as the adaptation of advances in biotechnology, molecular biology, and bioinformatics. Technical approaches developed for the prevention of contamination and recontamination of hardware during Assembly, Test, and Launch Operations will be discussed.

Kazarians, Gayane A.↗