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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 1,585 records · Page 88
All sourcesNASA NTRSDOE OSTI
NASA NTRS2014

Design Evolutuion of Hot Isotatic Press Cans for NTP Cermet Fuel Fabrication

Nuclear Thermal Propulsion (NTP) is under consideration for potential use in deep space exploration missions due to desirable performance properties such as a high specific impulse (> 850 seconds). Tungsten (W)-60vol%UO2 cermet fuel elements are under development, with efforts emphasizing fabrication, performance testing and process optimization to meet NTP service life requirements [1]. Fuel elements incorporate design features that provide redundant protection from crack initiation, crack propagation potentially resulting in hot hydrogen (H2) reduction of UO2 kernels. Fuel erosion and fission product retention barriers include W coated UO2 fuel kernels, W clad internal flow channels and fuel element external W clad resulting in a fully encapsulated fuel element design as shown.

Mireles, O. R.↗
DOE OSTI2017

Analysis and Experimental Qualification of an Irradiation Capsule Design for Testing Pressurized Water Reactor Fuel Cladding in the High Flux Isotope Reactor

The Advanced Fuels Campaign within the Fuel Cycle Research and Development program of the Department of Energy Office of Nuclear Energy is currently investigating a number of advanced nuclear fuel cladding concepts to improve the accident tolerance of light water reactors. Alumina-forming ferritic alloys (e.g., FeCrAl) are some of the leading candidates to replace traditional zirconium alloys due to their superior oxidation resistance, provided no prohibitive irradiation-induced embrittlement occurs. Oak Ridge National Laboratory has developed experimental designs to irradiate thin-walled cladding tubes with representative pressurized water reactor geometry in the High Flux Isotope Reactor (HFIR) under relevant temperatures. These designs allow for post-irradiation examination (PIE) of cladding that closely resembles expected commercially viable geometries and microstructures. The experiments were designed using relatively inexpensive rabbit capsules for the irradiation vehicle. The simplistic designs combined with the extremely high neutron flux in the HFIR allow for rapid testing of a large test matrix, thus reducing the time and cost needed to advanced cladding materials closer to commercialization. The designs are flexible in that they allow for testing FeCrAl alloys, stainless steels, Inconel alloys, and zirconium alloys (as a reference material) both with and without hydrides. This will allow a direct comparison of the irradiation performance of advanced cladding materials with traditional zirconium alloys. PIE will include studies of dimensional change, microstructure variation, mechanical performance, etc. This work describes the capsule design, neutronic and thermal analyses, and flow testing that were performed to support the qualification of this new irradiation vehicle.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRSDate not supplied

Development of Multilayered Coatings for Nerva-Type Graphite Fuel Elements- An Overview

“Mid-passage corrosion” (MPC) was observed in NbC and ZrC-coated graphite (Gr)-based nuclear fuels during the NERVA/Rover programs. A new multilayered coating concept was proposed to solve this problem. The concept envisions designing a compliant multilayered coatings architecture to accommodate the thermal expansion mismatch strains between the ZrC outer coating and the Gr/(U,Zr)C fuel matrix. Additionally, the coating architecture uses diffusion barriers to minimize carbon diffusion from the substrate, and hydrogen diffusion from the flowing gas stream, into the multilayer coating. The present paper provides a brief overview of the development of multilayered coatings deposited on Gr disks, as well as within the inner channels of a19-hole hexagonal rod 152.4 mm long, by chemical vapor deposition (CVD) in proof-of concept studies. The cross-sectional microstructural observations are discussed. These trials have established that it is possible to deposit multilayered coatings by CVD in 19-hole hexagonal rods similar to the NERVA fuel rod design although the quality of the coatings and the uniformity of their thicknesses require further improvement.

Multilayer coatings, graphite, nuclear thermal pro↗
DOE OSTI2018

Assessment of Methane Emissions – Impact of Using Natural Gas Engines in Unconventional Resource Development

Researchers at the Center for Alternative Fuels, Engines, and Emissions (CAFEE) completed a multi-year program under DE-FE0013689 entitled, “Assessing Fugitive Methane Emissions Impact Using Natural Gas Engines in Unconventional Resource Development.” When drilling activity was high and industry sought to lower operating costs and reduce emissions they began investing in dual fuel and dedicated natural gas engines to power unconventional well equipment. From a review of literature we determined that the prime-movers (or major fuel consumers) of unconventional well development were the service trucks (trucking), horizontal drilling rig (drilling) engines, and hydraulic stimulation pump (fracturing) engines. Based on early findings from on-road studies we assessed that conversion of prime movers to operate on natural gas could contribute to methane emissions associated with unconventional wells. As such, we collected significant in-use activity data from service trucks and in-use activity, fuel consumption, and gaseous emissions data from drilling and fracturing engines. Our findings confirmed that conversion of the prime movers to operate as dual fuel or dedicated natural gas – created an additional source of methane emissions. While some gaseous emissions were decreased from implementation of these technologies – methane and CO 2 equivalent emissions tended to increase, especially for non-road engines. The increases were highest for dual fuel engines due to methane slip from the exhaust and engine crankcase. Dedicated natural gas engines tended to have lower exhaust methane emissions but higher CO 2 emissions due to lower efficiency. Therefore, investing in currently available natural gas technologies for prime movers will increase the greenhouse gas footprint of the unconventional well development industry.

03 NATURAL GAS↗
DOE OSTI2022

Uncertainty in Thermal Modeling of Spent Nuclear Fuel Casks

Uncertainty is a key metric in computational modeling that must be evaluated for results to have wide ranging applicability. A well characterized uncertainty range is ideal with clear error bars on results that can be presented to stakeholders. In the field of spent fuel cask modeling, this ideal has been historically difficult to achieve in practice because of the computationally intensive nature of the models used and the difficulty assigning reasonable uncertainties to quantities in as-built systems. The work in this report has been conducted to evaluate the overall state of uncertainty and sensitivity in spent fuel cask models and develop methodologies for evaluating these uncertainties. These methodologies must be practical for engineering applications. They should not require excessive computational resources or calendar time to achieve results. In engineering, the model must be on a scale such that it can be changed and adapted throughout a project as new information is discovered and project goals evolve. This report covers three major modeling task areas that provide an overview of the types of sensitivity and uncertainty present in a spent fuel storage and transportation system. Section 3 discusses sensitivity and uncertainty analysis in the effective thermal conductivity model for the fuel region and applies these results to a single assembly model. Section 4 shows sensitivity analysis of a full cask model in the TN-32B and Section 5 demonstrates the overall uncertainty workflow using Coolant Boiling in Rod Arrays – Spent Fuel Storage and STAR-CCM+ developed from the sensitivity work in the preceding sections.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1980

Vaporization of droplets in premixing chambers

Detailed measurements were made of the structures of turbulent fuel sprays vaporizing in heated airstreams. The measurements show the size dependent vaporization and dispersion of the droplets and the important influence of the large eddies in the turbulence. The measurements form a data base for the development of models of fuel spray vaporization. Two laser techniques were specially developed for the investigation. A laser tomography technique converts line-of-sight light scattering measurements into time averaged 'point' measurements of droplet size distribution and volume concentration. A laser anemometer particle sizing technique was further developed to permit accurate measurements of individual particle sizes and velocities, with backscatter collection of light. The experiments are combined with heat transfer models to analyze the performance of miniature thermocouples in liquid sprays.

Yule, A. J.↗
DOE OSTI2019

Co-Optimization of Fuels & Engines: FY18 Year in Review

The U.S. Department of Energy (DOE) Co-Optima initiative is accelerating the introduction of efficient, clean, affordable, and scalable high-performance fuels and engines. This first-of-its-kind effort is simultaneously tackling fuel and engine research and development (R&D) to maximize light, medium, and heavy-duty vehicle fuel economy and performance, while mapping lower-cost pathways to reduce emissions, leveraging diverse domestic fuel resources, boosting U.S. economic productivity, and enhancing national energy security. Co-Optima brings together DOE's Office of Energy Efficiency & Renewable Energy (EERE), nine national laboratories, 13 universities, and numerous industry and government stakeholders in a collaboration exploring solutions with potential for near-term improvements to the types of fuels and engines found in most vehicles currently on the road, as well as potential for the development of revolutionary new engine technologies.

09 BIOMASS FUELS↗
DOE OSTI2018

Multidimensional Numerical Simulations of Knocking Combustion in a Cooperative Fuel Research Engine

A numerical approach was developed based on multidimensional computational fluid dynamics (CFD) to predict knocking combustion in a cooperative fuel research (CFR) engine. G-equation model was employed to track the turbulent flame front and a multizone model was used to capture auto-ignition in the end-gas. Furthermore, a novel methodology was developed wherein a lookup table generated from a chemical kinetic mechanism could be employed to provide laminar flame speed as an input to the Gequation model, instead of using empirical correlations. To account for fuel chemistry effects accurately and lower the computational cost, a compact 121-species primary reference fuel (PRF) skeletal mechanism was developed from a detailed gasoline surrogate mechanism using the directed relation graph (DRG) assisted sensitivity analysis (DRGASA) reduction technique. Extensive validation of the skeletal mechanism was performed against experimental data available from the literature on both homogeneous ignition delay and laminar flame speed. The skeletal mechanism was used to generate lookup tables for laminar flame speed as a function of pressure, temperature, and equivalence ratio. The numerical model incorporating the skeletal mechanism was employed to perform simulations under research octane number (RON) and motor octane number (MON) conditions for two different PRFs. Parametric tests were conducted at different compression ratios (CR) and the predicted values of critical CR, delineating the boundary between “no knock” and “knock,” were found to be in good agreement with available experimental data. The virtual CFR engine model was, therefore, demonstrated to be capable of adequately capturing the sensitivity of knock propensity to fuel chemistry.

CFD↗
DOE OSTI2025

Testing piezoelectric sensors in a nuclear reactor environment

Several Department of Energy Office of Nuclear Energy (DOE-NE) programs, such as the Fuel Cycle Research and Development (FCRD), Advanced Reactor Concepts (ARC), Light Water Reactor Sustainability, and Next Generation Nuclear Power Plants (NGNP), are investigating new fuels, materials, and inspection paradigms for advanced and existing reactors. A key objective of such programs is to understand the performance of these fuels and materials during irradiation. In DOE-NE’s FCRD program, ultrasonic based technology was identified as a key approach that should be pursued to obtain the high-fidelity, high-accuracy data required to characterize the behavior and performance of new candidate fuels and structural materials during irradiation testing. The radiation, high temperatures, and pressure can limit the available tools and characterization methods. In this work piezoelectric transducers capable of making these measurements are developed. Specifically, three piezoelectric sensors (Bismuth Titanate, Aluminum Nitride, and Zinc Oxide) are tested in the Massachusetts Institute of Technology Research reactor to a fast neutron fluence of 8.65x1020 nf/cm2. It is demonstrated that Bismuth Titanate is capable of transduction up to 5 x1020 nf/cm2, Zinc Oxide is capable of transduction up to at least 6.27 x1020 nf/cm2 , and Aluminum Nitride is capable of transduction up to at least 8.65x x1020 nf/cm2.

T. Reinhardt, Brian↗
DOE OSTI2022

An experimental and modeling study on auto-ignition kinetics of ammonia/methanol mixtures at intermediate temperature and high pressure

A rapid compression machine (RCM) has been applied to measure the ignition delay times of NH 3 /CH 3 OH mixtures covering pressures of 20 and 40 bar, equivalence ratios of 0.5, 1.0 and 2.0, and temperatures between 845 and 1100 K. Here the measurements show that the NH 3 /CH 3 OH mixtures become more reactive with increasing methanol addition. Addition of merely 1% (molar basis) of CH 3 OH to NH 3 lowers the ignition temperature around 100 K at 40 bar in comparison to pure NH 3 . The ignition delay is a complex function of fuel mixture and stoichiometry. For the 1% CH 3 OH mixture, the leaner mixtures are more reactive, while the reverse trend is found for mixtures with 5%, 20% and pure CH 3 OH. Analysis of the pressure profiles shows three distinct ignition modes for NH 3/ CH 3 OH mixtures, facilitated by the pre-ignition heat release from NH 3 consumption. A detailed mechanism for ignition of NH 3 /CH 3 OH fuel blends has been developed, capable of reproducing the ignition behavior of mixtures with reasonable accuracy. A subset for amine / methanol interactions was established, with rate constants for the key reaction between NH 2 and CH 3 OH calculated from ab initio theory. A sensitivity analysis indicates that the critical reactions during the auto-ignition process vary with the CH 3 OH mole fraction in the fuel. The ammonia chemistry, namely NH 2 + NO, NH2 + NO 2 and NH 2 + HO 2 , is dominant for the mixture with 1% CH 3 OH, while the reactions related to CH 3 OH and H 2 O 2 are more important for the 20% CH 3 OH mixture. The interaction between ammonia and methanol shows a more prominent effect on auto-ignition for mixtures with 5% CH 3 OH in fuel as compared to those with 1% and 20% CH 3 OH. According to the modeling results, methanol addition is found to enrich the O/H radical pool, consuming ammonia and promoting auto-ignition through different reaction pathways.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Enabling Coal Technology with Carbon Capture for Future Markets with Flameless Pressurized Oxy-Combustion (FPO)

Future markets for power are expected to require more load following power plants, which reduces output during the night and early morning. This is when the demand for electricity is the lowest, so plants must respond rapidly at any time to peak loads resulting from the variable output of wind and solar power. A coal power plant based on Flameless Pressurized Oxy-combustion (FPO) can go from 5% to 100% of capacity rate in less than 30 minutes in response to fluctuating demand, operating at capacity when power prices are highest. FPO is a proven oxy-combustion technology that was developed to recover energy from low ranking coal, other brown fuels and wastes. ITEA began developing FPO in 2003 on a 5-MWth pilot in Gioia del Colle, Italy, to destroy hazardous industrial waste and as such, design objectives were very high combustion efficiencies and capture of metals in the fuel in the vitreous slag. The technology was subsequently deployed in 2009 at the 15-MWth scale at the Jurong Island petrochemical cluster in Singapore for waste incineration. FPO is an oxy-combustion process whereby oxygen is separated from the air, and it is used in combustion with recirculated flue gas to maintain combustion temperatures at acceptable levels. The resultant flue gas is primarily CO 2 and water, which allows for a relatively simple and cheap CO 2 capture process. This is in contrast to air-combustion systems which require a complex and costly post-combustion capture (PCC) process. Coal is fed to the combustor slurried in water, and the combustor operates at elevated pressure (approximately 12 bar) which improves the overall efficiency and reduces the size and cost of the combustor. Notably, the FPO cycle maintains high efficiency by recovering most of the heat of vaporisation of the contained water. The combustor is designed to coalesce the molten ash particles so that they settle to the chamber walls and drain to the outlet, significantly reducing the particulate content in the exhaust gas and allowing the use of coals with up to 40% alkaline ash content. FPO is a low-emission technology: zero thermal NOx minimises overall NOx; any organic nitrogen is converted to elemental nitrogen (N2). Total organic content (TOC) at combustor exit is hundreds of times lower than for traditional combustion processes, with dioxin and furans close to zero. Work commenced on a DOE funded pilot demonstration project in October 2016 to provide the design for a 50-MWth FPO pilot plant that can fire a wide range of high-to-low rank coals. The project will investigate updating and improving the cycle for power generation with CO 2 capture by incorporating a turbo-expander with a principal steam power island that utilizes a heat recovery steam generator, increasing the overall efficiency of the cycle. A cost study is also performed on the updated FPO design as part of the project. The FPO pilot plant built based on the design will then be demonstrated over a 3-year test program to generate data for the design of a commercial-scale 500 MWth firing module commercial power plant with integral carbon capture and sequestration (CCS), which could start construction in 2025. A discussion of the levelized cost of electricity (LCOE) of various cases are presented, including a comparison of established supercritical with PCC (SCPC) technologies with FPO fitted with CO 2 compression and liquefaction, and FPO ready for carbon capture and sequestration (CCS-ready). This would enable CO 2 capture for use in enhanced oil recovery (EOR) or sequestration when market conditions make it attractive to do so. In addition, a comparison of LCOE of FPO and conventional processes for firing low-ranking coals with high water and ash content will be provided.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2022

Feedstock Carbon Intensity Calculator (FD-CIC): Users’ Manual and Technical Documentation

The carbon intensities (CIs) of biofuels are determined with the life cycle analysis (LCA) technique, which accounts for the energy/material uses and emissions during the complete supply chain of biofuel including feedstock production and fuel conversion stages. Regulatory agencies such as California Air Resources Board (CARB) adopts LCA to calculate biofuel CIs. The Low Carbon Fuel Standard (LCFS) program developed by CARB allows individual biofuel conversion facilities to submit their own biofuel CIs with their facility input data and incentivizes the reduction in the CI specific to that particular facility compared to a reference fuel’s CI (Liu et al 2020). Such an incentive program has driven innovations in biorefineries to reduce their greenhouse gas (GHG) emissions by linking their revenue directly to its CI score through LCFS credit trading. Besides the biofuel conversion stage, different farming practices for feedstock growth can result in significant CI variations for feedstocks, thus for biofuels. To provide evidence-based research findings, the U.S. Department of Energy’s Advanced Research Projects Agency–Energy (ARPA-E) has supported the Systems Assessment Center of the Energy Systems and Infrastructure Analysis Division at Argonne National Laboratory to examine CI variations of different farming practices to grow agricultural crops for biofuel production. Meanwhile, the ARPA-E has launched the Systems for Monitoring and Analytics for Renewable Transportation Fuels from Agricultural Resources and Management (SMARTFARM) program to develop technologies and data platforms that enable an accurate measurement of key farming parameters that can help robust accounting of the GHG benefits of sustainable, low-carbon agronomic practices at farm level.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

STAT7 v1.2 User Guide: The STAT7 Code for Statistical Propagation of Uncertainties in Steady-State Thermal Hydraulics Analysis of Plate-Fueled Reactors

The STAT7 software was developed to perform steady-state, single-phase thermal hydraulics analysis of plate-fueled reactors based on statistical propagation of uncertainties. Application of the software is for non-power research and test reactors, including conversion to low-enriched uranium fuel of U.S. High-Performance Research Reactors such as Massachusetts Institute of Technology Research Reactor. Since it can be necessary to repeat analysis during fuel reloading, STAT7 accommodates flexibility in analyzing many realistic aspects of reactor fuel management. STAT7 uses a Monte Carlo approach to model uncertainty in common fuel fabrication parameters and other key reactor operating parameters required for thermal hydraulics analyses of research and test reactors. These safety calculations are ultimately intended to protect against high fuel plate temperatures due to critical heat flux, or onset of flow instability. STAT7 supports water properties based on the IAPWS-IF97 functions (The International Association for the Properties of Water and Steam Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam) in addition to the fit functions. STAT7 predicts axial profiles of fuel, cladding, and coolant temperature along a lateral stripe that runs the full length of the fuel plate from the bottom to the top. STAT7 can simultaneously analyze all of the axial nodes of all of the fuel plates and all of the coolant channels for one latera stripe of a fuel element. Power splits are calculated for each axial node of each plate to determine how much of the power goes out each face of the plate. By running STAT7 multiple times, full core analysis can be performed by analyzing the margin to onset of nucleate boiling and onset of flow instability for each axial node of each stripe of each plate of each fuel element in the core.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS1984

Broad specification fuels combustion technology program

Design and development efforts to evolve promising aircraft gas turbine combustor configurations for burning broadened-properties fuels were discussed. Design and experimental evaluations of three different combustor concepts in sector combustor rig tests was conducted. The combustor concepts were a state of the art single-annular combustor, a staged double-annular combustor, and a short single-annular combustor with variable geometry to control primary zone stoichiometry. A total of 25 different configurations of the three combustor concepts were evaluated. Testing was conducted over the full range of CF6-80A engine combustor inlet conditions, using four fuels containing between 12% and 14% hydrogen by weight. Good progress was made toward meeting specific program emissions and performance goals with each of the three combustor concepts. The effects of reduced fuel hydrogen content, including increased flame radiation, liner metal temperature, smoke, and NOx emissions were documented. The most significant effect on the baseline combustor was a projected 33% life reduction, for a reduction from 14% to 13% fuel hydrogen content, due to increased liner temperatures.

Dodds, W. J.↗
DOE OSTI2025

Development of advanced vacuum technologies for extending plasma pulse duration on EAST

Advanced vacuum technologies, including pumping, fueling and wall conditioning, have been successfully developed or upgraded to efficiently control the fuel and impurity particles to extend the plasma pulse duration in the experimental advanced superconducting tokamak (EAST). To improve the particle exhaust rate cryopumps with a 60% increase in pumping speed and ∼2 times increase in saturation capacity have been developed, and molecular pumps with a ∼30% increase in pumping speed have been upgraded. In order to monitor the molecular pump status while avoiding bearing faults and overload accidents, a fault detection system has been built which can offer an early warning to avoid more losses within the fusion device. A series of fueling technologies have been developed including gas injection system, supersonic molecular beam injector, pellet injector (PI), massive gas injector and shattered pellet injector, installed at the midplane and divertor positions at different ports to improve fueling uniformity and efficiency. Meanwhile, routine wall conditioning such as electric and hot N 2 baking, ion cyclotron wall conditioning and glow discharge cleaning have been successfully developed to remove the impurity particles from the inner component and materials. The low Z material wall coating and real-time powder injection during plasma discharge are also designed and applied to further improve particle control capability. Finally, by using these advanced vacuum related technologies, good vacuum (<2 × 10 −6 Pa) and wall conditions are realized, and the fuel and impurity particles can be effectively and stably controlled, which promotes the achievement of the record plasma of ∼1056 s pulse duration with the line-averaged electron density of 1.8 × 10 19 m −3 on EAST. They provide a very important reference for vacuum system design and operation for future fusion devices.

EAST↗
NASA NTRS1992

The NASA hypersonic research engine program

An overview is provided of the NASA Hypersonic Research Engine Program. The engine concept is described which was evolved, and the accomplishments of the program are summarized. The program was undertaken as an in-depth program of hypersonic airbreathing propulsion research to provide essential inputs to future prototype engine development and decision making. An airbreathing liquid hydrogen fueled research oriented scramjet was to be developed to certain performance goals. The work was many faceted, required aerodynamic design evaluation, structures development, and development of flight systems such as the fuel and control system, but the main objective was the study of the internal aerothermodynamics of the propulsion system.

Rubert, Kennedy F.↗
DOE OSTI2019

Development of NiO-Nanocarbon and MnO{sub 2}-Nanocarbon Energetic Catalytic Electrode Materials to Synthesize Electrical Energy through Electrochemical Oxidation of Glucose

Automobile and transportation on land and in air are the major causes of global environment pollution through the chemical combustion of petroleum fuels. The need of the hour is to run the transportation units by fuel cells which convert fuels to energy through electrochemical oxidation, straight to pure electrical energy with no polluting substances. Development of fuel cell lies on exhaustive research on development of high energetic electrocatalytic electrodes over which the fuels break to produce free electron and ions, delivering electrical energy. The present work aims at developing two electrocatalytic materials: NiO-nanocarbon and MnO{sub 2}-nanocarbon by electrosynthesis method. The performance of the materials was investigated by electrochemical characterization: cyclic voltammetry, chronoammetry, polarization tests and impedance spectroscopy. The materials were found to deliver a high current on electro-oxidation of glucose. The effect of nanocarbon on NiO and MnO{sub 2} has enhanced the current to a level of over 100 mA/cm{sup 2}. XRD study showed the presence of metal oxides and carbon. The electron microscopy images revealed fine grain oxides with entrapped nanocarbon. The carbon seems to be in the form of graphene, produced during electrochemical exfoliation at anode. The SEM morphology of enhanced 3D surface area with high energetic nanocarbon phase entrapped with fine structure metal oxides accounts for the high current obtained by electro-oxidation of the fuel. The materials developed are found to be very good energetic electrodes for future fuel cell in automotive industry.

36 MATERIALS SCIENCE↗