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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Assessment of Sandia's 2021 Pilot Program for Research Traineeships to Broaden and Diversify Fusion Energy Science: Development and Rapid Screening of Refractory Multi-Principal Elemental Composites for Plasma Facing Components

The Fusion Energy Sciences office supported “A Pilot Program for Research Traineeships to Broaden and Diversify Fusion Energy Sciences” at Sandia National Laboratories during the summer of 2021. This pilot project was motivated in part by the Fusion Energy Sciences Advisory Committee report observation that “The multidisciplinary workforce needed for fusion energy and plasma science requires that the community commit to the creation and maintenance of a healthy climate of diversity, equity, and inclusion, which will benefit the community as a whole and the mission of FES”. The pilot project was designed to work with North Carolina A&T (NCAT) University and leverage SNL efforts in FES to engage underrepresented students in developing and accessing advanced material solutions for plasma facing components in fusion systems. The intent was to create an environment conducive to the development of a sense of belonging amongst participants, foster a strong sense of physics identity among the participants, and provide financial support to enable students to advance academically while earning money. The purpose of this assessment is to review what worked well and lessons that can be learned. We reviewed implementation and execution of the pilot, describe successes and areas for improvement and propose a no-cost extension of the pilot project to apply these lessons and continue engagement activities in the summer of 2022.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Data Fusion via Neural Network Entropy Minimization for Target Detection and Multi-Sensor Event Classification

Broadly applicable solutions to multimodal and multisensory fusion problems across domains remain a challenge because effective solutions often require substantive domain knowledge and engineering. The chief questions that arise for data fusion are in when to share information from different data sources, and how to accomplish the integration of information. The solutions explored in this work remain agnostic to input representation and terminal decision fusion approaches by sharing information through the learning objective as a compound objective function. The objective function this work uses assumes a one-to-one learning paradigm within a one-to-many domain which allows the assumption that consistency can be enforced across the one-to-many dimension. The domains and tasks we explore in this work include multi-sensor fusion for seismic event location and multimodal hyperspectral target discrimination. We find that our domain- informed consistency objectives are challenging to implement in stable and successful learning because of intersections between inherent data complexity and practical parameter optimization. While multimodal hyperspectral target discrimination was not enhanced across a range of different experiments by the fusion strategies put forward in this work, seismic event location benefited substantially, but only for label-limited scenarios.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Key Goals and Innovations Needed for a U.S. Compact Fusion Pilot (Final Technical Report)

Fusion energy offers the prospect of addressing the nation's energy needs and contributing to the transition to a low-carbon emission electrical generation infrastructure. Technology and research results from U.S. investments in the major fusion burning plasma experiment known as ITER, coupled with a strong foundation of research funded by the Department of Energy (DOE), position the United States to begin planning for its first fusion pilot plant. Strong interest from the private sector is an additional motivating factor, as the process of decarbonizing and modernizing the nation's electric infrastructure accelerates and companies seek to lead the way. At the request of DOE, Bringing Fusion to the U.S. Grid builds upon the work of the 2019 report Final Report of the Committee on a Strategic Plan for U.S. Burning Plasma Research to identify the key goals and innovations - independent of confinement concept - that are needed to support the development of a U.S. fusion pilot plant that can serve as a model for producing electricity at the lowest possible capital cost.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Opportunities in Pulsed Magnetic Fusion Energy

Fusion is a potentially transformational energy technology, which promises limitless clean energy. Yet, it requires continued scientific and technological development to realize its potential. The conditions necessary for fusion energy gain in terms of the product of plasma pressure P and confinement time $\tau$ have been known for many decades. An underappreciated fact is that pulsed magnetic fusion has demonstrated P $\tau$ performance on par with laser-driven ICF and tokamaks despite receiving only a small fraction of investment relative to those concepts. In light of this demonstrated performance, well-established scaling relations, and opportunities for further innovations, here we advocate for pulsed magnetic fusion as the most attractive path towards commercialization of fusion energy.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Development and Qualification of Advanced Alloys Used in High Helium and Displacement Damage Service for Fusion Energy Applications

This document represents a final report on the Department of Energy (DOE) Office of Science, Office of Fusion Energy Science (OFES) Grant Entitled “Development and Qualification of Advanced Alloys Used in High Helium and Displacement Damage Service for Fusion Energy Applications” (DE-FG02-94ER54275). This grant has been funded since 1994, by a series of five and three-year renewals. We express our deep appreciation for the long-standing support by OFES for our fusion materials research. The latest three-year renewal was awarded in 2019. This renewal subsequently received a 1- year no-cost extension, followed by another funded 1-year phaseout period. Here, we focus on this five-year effort. The final report is composed of 35 Fusion Semiannual Reports covering the period from 2019 to 2024. In addition, Appendix A lists 158 fusion materials papers published since 1994, with the partial, or full, support of the OFES program. We note that, as metrics of their high impact, these papers have received a total of 8582 citations, with an average of 54 per paper.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Detection of Foreign Materials on Broiler Breast Meat Using a Fusion of Visible Near-Infrared and Short-Wave Infrared Hyperspectral Imaging

Foreign material (FM) found on a poultry product lowers the quality and safety of the product. We developed a fusion method combining two hyperspectral imaging (HSI) modalities in the visible-near infrared (VNIR) range of 400–1000 nm and the short-wave infrared (SWIR) range of 1000–2500 nm for the detection of FMs on the surface of fresh raw broiler breast fillets. Thirty different types of FMs that could be commonly found in poultry processing plants were used as samples and prepared in two different sizes (5 × 5 mm 2 and 2 × 2 mm 2 ). The accuracies of the developed Fusion model for detecting 2 × 2 mm 2 pieces of polymer, wood, and metal were 95%, 95%, and 81%, respectively, while the detection accuracies of the Fusion model for detecting 5 × 5 mm 2 pieces of polymer, wood, and metal were all 100%. The performance of the Fusion model was higher than the VNIR- and SWIR-based detection models by 18% and 5%, respectively, when F1 scores were compared, and by 38% and 5%, when average detection rates were compared. The study results suggested that the fusion of two HSI modalities could detect FMs more effectively than a single HSI modality.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Nuclear diagnostics for Inertial Confinement Fusion (ICF) plasmas

The field of nuclear diagnostics for Inertial Confinement Fusion (ICF) is broadly reviewed from its beginning in the seventies to present day. During this time, the sophistication of the ICF facilities and the suite of nuclear diagnostics have substantially evolved, generally a consequence of the efforts and experience gained on previous facilities. As the fusion yields have increased several orders of magnitude during these years, the quality of the nuclear-fusion-product measurements has improved significantly, facilitating an increased level of understanding about the physics governing the nuclear phase of an ICF implosion. The field of ICF has now entered an era where the fusion yields are high enough for nuclear measurements to provide spatial, temporal and spectral information, which have proven indispensable to understanding the performance of an ICF implosion. At the same time, the requirements on the nuclear diagnostics have also become more stringent. To put these measurements into context, this review starts by providing some historical remarks about the field of ICF and the role of nuclear diagnostics, followed by a brief overview of the basic physics that characterize the nuclear phase and performance of an ICF implosion. A technical discussion is subsequently presented of the neutron, gamma-ray, charged-particle and radiochemistry diagnostics that are, or have been, routinely used in the field of ICF. This discussion is followed by an elaboration of the current view of the next-generation nuclear diagnostics. Since the seventies, the overall progress made in the areas of nuclear diagnostics and scientific understanding of an ICF implosion has been enormous, and with the implementation of new high-fusion-yield facilities world-wide, the next-generation nuclear diagnostics will play an even more important role for decades to come.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Design of inertial fusion implosions reaching the burning plasma regime

One of the last remaining milestones in fusion research before reaching ignition is creating a burning plasma state, where alpha particles from deuterium-tritium (DT) fusion reactions redeposit their energy as the dominant source of heating in the plasma. The indirect-drive inertial confinement fusion approach at the National Ignition Facility (NIF) uses a laser-generated radiation cavity (hohlraum) to spherically implode DT fuel to high temperatures and densities in a central ”hot spot”. Here, we deliver more energy to the hot spot than ever before, while maintaining the extreme pressures required for inertial confinement, by increasing the size of the implosion compared to previous experiments. We develop more efficient hohlraums, to drive these larger implosions within NIF’s current laser energy and power capability and control symmetry by moving energy between laser beams and by changing the shape of the hohlraum. These designs resulted in record fusion powers of 1.5 petawatts, greater than the input power of the laser, and 170 kJ of fusion energy. Radiation hydrodynamics simulations show alpha particle heating as the dominant term in the hot spot energy balance, e.g. a burning plasma state. This work is expected to motivate future studies of burning plasmas and improve predictive capability by providing a benchmark for modeling used to understand the proximity to ignition.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS2014

Recent Advances in Registration, Integration and Fusion of Remotely Sensed Data: Redundant Representations and Frames

In recent years, sophisticated mathematical techniques have been successfully applied to the field of remote sensing to produce significant advances in applications such as registration, integration and fusion of remotely sensed data. Registration, integration and fusion of multiple source imagery are the most important issues when dealing with Earth Science remote sensing data where information from multiple sensors, exhibiting various resolutions, must be integrated. Issues ranging from different sensor geometries, different spectral responses, differing illumination conditions, different seasons, and various amounts of noise need to be dealt with when designing an image registration, integration or fusion method. This tutorial will first define the problems and challenges associated with these applications and then will review some mathematical techniques that have been successfully utilized to solve them. In particular, we will cover topics on geometric multiscale representations, redundant representations and fusion frames, graph operators, diffusion wavelets, as well as spatial-spectral and operator-based data fusion. All the algorithms will be illustrated using remotely sensed data, with an emphasis on current and operational instruments.

Fusion↗
NASA NTRS2018

Pulsed Fission-Fusion (PuFF)

In September 2013 the NASA Innovative Advanced Concept (NIAC) organization awarded a phase I contract to the PuFF team. Our phase 1 proposal discussed a pulsed fission-fusion propulsion system that injected gaseous deuterium (D) and tritium (T) as a mixture in a column, surrounded concentrically by gaseous uranium fluoride (UF6) and then an outer shell of liquid lithium. A high power current would flow down the liquid lithium and the resulting Lorentz force would compress the column by roughly a factor of 10. The compressed column would reach criticality and a combination of fission and fusion reactions would occur. The fission reactions would further energize the fusion center, and the fusion reactions would generate neutrons that promote more complete burnup of the fission fuel. The lithium liner provides some help as a neutron reflector but also acts as a propulsive medium, being converted to plasma which is then expanded against a magnetic nozzle for thrust. The expansion of the (primarily) lithium plasma against the nozzle's magnetic field inducts a current that is used to charge the system for the next pulse. Our concept also included secondary injection of a Field Reversed Configuration (FRC) plasmoid that would provide a secondary compression direction, axially against the column, and push the column away from the injection manifold, increasing the manifold's survivability.Our phase 1 proposal included modeling the above process first under steady state assumptions and second under a time variant integration. We proposed including these results into a Mars concept vehicle and finally proposing promising conditions to be evaluated experimentally in Phase II. In phase I we quickly realized that we needed to modify our approach. Our steady state work was completed as proposed, and the results indicated that one, a two stage compression system was not needed and two, that we wanted to move away from UF6. The steady state model shows much more margin than expected, to the point that we may well reach breakeven with the Charger – 1 facility, a 572 kJ Marx bank currently under refurbishment at UAH. Additionally we found that using gaseous D-T and UF6, provided a relatively simple prospect of using a pulsed injector, made reaching criticality more difficult. The introduction of large amounts of fluorine meant a radiative sink, sapping power from the fusion plasma and was harder to handle. Therefore we moved to a solid uranium target that held D-T under pressure. In so doing we could move our target closer to criticality and remove any material that did not sustain the reaction.

Fusion↗
DOE OSTI2025

STORM: Scrape-off layer turbulence in tokamak fusion reactors

The scrape-off layer of a tokamak fusion reactor carries the plasma exhaust from the hot core plasma to the material surfaces of the reactor vessel. The heat loads imposed by the exhaust are a critical limit on the performance of fusion power plants. Turbulent transport of the plasma regulates the width of the scrape-off layer plasma and must be modelled to understand the intensity of these heat loads. STORM is a plasma turbulence code capable of simulating three dimensional turbulence across the full scrape-off layer of a tokamak fusion reactor, using a drift reduced, collisional fluid model. STORM uses mostly finite difference schemes, with a staggered grid in the direction parallel to the magnetic field. We describe the model, geometry and initialisation options used by STORM, as well as the numerical methods, which are implemented using the BOUT++ plasma simulation framework. BOUT++ has been enhanced alongside the development of STORM, providing better support for staggered grid methods. We summarise these enhancements, including a detailed explanation of the parallel derivative methods, which underwent a major update for version 4 of BOUT++.

BOUT++↗
DOE OSTI2026

State of the art, gaps, and prospects in fusion materials theory and modelling

Advancing the theory and simulation of materials for fusion applications remains a key component of global roadmaps aimed at delivering much-needed fusion power. Especially as the drive for commercial application increases, prototypes must be designed against radiation damage before the relevant experimental data can be collected and cost reductions that are possible by testing materials in silico become even more important. Here, we summarise the state of the art as it emerged during the 7 th Fusion Materials Theory & Modelling Workshop that took place in 2024, with the aim to highlight present gaps and future directions for the fusion materials modelling community. Of particular interest were the effects of transmutations, chemical complexity with the development of novel alloys and interatomic potentials, advancements in modelling high-dose microstructures, comparison with experimental data and multiscale models for structural assessment relying on high-performance computing and virtual reality.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Progress with applications of three-ion ICRF scenarios for fusion research: A review

The viability of magnetic confinement fusion as an energy source depends on achieving the high ion temperatures required for D-T fusion. Among the available techniques, plasma heating with waves in the ion cyclotron range of frequencies (ICRF) is a prominent method for bulk ion heating in fusion plasmas. Furthermore, a detailed understanding of the non-linear physics of alpha heating and the complex impact of MeV-range fast ions on plasma dynamics becomes progressively more important. This paper provides a comprehensive overview of recent developments with the three-ion ICRF scenarios on Alcator C-Mod, ASDEX Upgrade and JET tokamaks. The results demonstrate the flexibility of these novel scenarios for heating bulk ions in D-T ≈ 50%-50% plasmas and efficient generation of MeV-range fast ions in multi-ion species plasmas. In conclusion, several key results relevant for ITER and future fusion reactors are highlighted.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2026

Bremsstrahlung constraints on proton-boron 11 inertial fusion

Proton-boron 11 (pB11) fusion is relatively safe and clean, but difficult to use for net power production, since bremsstrahlung radiation tends to radiate away power more quickly than it can be generated by fusion power, particularly once poisoning by alpha particles is taken into account. While in magnetic confinement fusion, this problem can be addressed by deconfining the alphas, in inertial confinement fusion (ICF), the alphas that heat the plasma linger for the duration of the reaction. Thus, it becomes essential to trap the bremsstrahlung radiation in the hotspot. Through burn simulations incorporating bremsstrahlung emission and reabsorption, we infer the necessary conditions to capture enough radiation to produce scientific breakeven in a pB11 ICF plasma. We find that breakeven requires a stagnation areal density roughly two orders of magnitude higher than the current state-of-the-art, at pressures three orders of magnitude higher.

Alpha particles↗
DOE OSTI2026

Studies of localized mix and asymmetry caused by the stalk in inertial fusion experiments at OMEGA

In an inertially confined fusion experiment, a capsule of fusion fuel is compressed to high temperatures and densities using lasers, creating a hot plasma in which thermonuclear fusion reactions take place. To achieve efficient conversion of laser energy to fuel heating, the implosion must be as spherically symmetric as possible. One common source of asymmetry that degrades performance is the stalk and glue spot that hold the capsule in place before the experiment. The exact nature and magnitude of this perturbation had not been previously quantified. In this work, inertially confined fusion experiments were executed with an additional stalk on the capsule to measure and quantify the effect of the stalk and glue spot on the symmetry and performance. It is found that the stalk drives low-mode asymmetry by shadowing the laser drive on the part of the shell near the glue spot, enhancing the hot-spot velocity toward the stalk by 40–80 km/s and elongating the hot-spot along the stalk axis. It is also found that localized mix due to the additional stalk has a negligible effect on implosion performance. Two-dimensional radiation-hydrodynamic simulations using the xRAGE code reproduce the direction of the experimentally observed change to hot-spot velocity and implosion performance metrics, but not the observed elongation, suggesting that this feature results from an interaction between stalk perturbations and other preexisting asymmetry seeds, such as laser drive asymmetry.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Irradiation damage concurrent challenges with RAFM and ODS steels for fusion reactor first-wall/blanket: a review

Reduced activation ferritic martensitic (RAFM) and oxide dispersion strengthened (ODS) steels are the most promising candidates for fusion first-wall/blanket (FW/B) structures. The performance of these steels will deteriorate during service due to neutron damage and transmutation-induced gases, such as helium/hydrogen, at elevated operating temperatures. Here, after highlighting the operating conditions of fusion reactor concepts and a brief overview, the main irradiation-induced degradation challenges associated with RAFM/ODS steels are discussed. Their long-term degradation scenarios such as (a) low-temperature hardening embrittlement (LTHE)—including dose-temperature dependent yield stress, tensile elongations, necking ductility, test temperature effect on hardening, Charpy impact ductile-to-brittle transition temperature and fracture toughness, (b) intermediate temperature cavity swelling, (c) the effect of helium on LTHE and cavity swelling, (d) irradiation creep and (e) tritium management issues are reviewed. The potential causes of LTHE are discussed, which highlights the need for advanced characterisation techniques. The mechanical properties, including the tensile/Charpy impact of RAFM and ODS steels, are compared to show that the current generation of ODS steels also suffers from LTHE, and shows irradiation hardening up to high temperatures of ~400 °C–500 °C. To minimise this, future ODS steel development for FW/B-specific application should target materials with a lower Cr concentration (to minimise α'), and minimise other elements that could form embrittling phases under irradiation. RAFM steel-designing activities targeting improvements in creep and LTHE are reviewed. The need to better understand the synergistic effects of helium on the thermo-mechanical properties in the entire temperature range of FW/B is highlighted. Because fusion operating conditions will be complex, including stresses due to the magnetic field, primary loads like coolant pressure, secondary loads from thermal gradients, and due to spatial variation in damage levels and gas production rates, an experimentally validated multiscale modelling approach is suggested as a pathway to future reactor component designing such as for the fusion neutron science facility.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Direct drive with the argon fluoride laser as a path to high fusion gain with sub-megajoule laser energy

Argon fluoride (ArF) is currently the shortest wavelength laser that can credibly scale to the energy and power required for high gain inertial fusion. ArF's deep ultraviolet light and capability to provide much wider bandwidth than other contemporary inertial confinement fusion (ICF) laser drivers would drastically improve the laser target coupling efficiency and enable substantially higher pressures to drive an implosion. Our radiation hydrodynamics simulations indicate gains greater than 100 are feasible with a sub-megajoule ArF driver. Our laser kinetics simulations indicate that the electron beam-pumped ArF laser can have intrinsic efficiencies of more than 16%, versus about 12% for the next most efficient krypton fluoride excimer laser. We expect at least 10% ‘wall plug' efficiency for delivering ArF light to target should be achievable using solid-state pulsed power and efficient electron beam transport to the laser gas that was demonstrated with the U.S. Naval Research Laboratory's Electra facility. These advantages could enable the development of modest size and lower cost fusion power plant modules. This would drastically change the present view on inertial fusion energy as being too expensive and the power plant size too large.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Quantifying resonance behavior in the fusion of O 17 with C 12 at above-barrier energies

Recent measurement of the fusion excitation function for 17 O + 12 C reported the significant suppression of the fusion cross section at E c.m. ≈ 14 MeV. This suppression was hypothesized to signal the existence of a 16 O + n + 12 C molecular configuration. Using the active-target detector MuSIC@Indiana provided an effective means of reexamining the fusion excitation function for 17 O + 12 C.The accuracy of this thick-target measurement is strengthened through comparison with the thin-target measurement of the excitation function for 17 F + 12 C. Furthermore, the result provides important information about the dependence of the average fusion cross section for the oxygen isotopic chain on neutron excess.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗