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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 793 records · Page 44
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Investigation of an r-f radiant energy source with uranium hexafluoride and tungsten hexafluoride injection.

An experimental investigation was conducted using the UARL 1.2-megw r-f induction heater to simulate thermal environment and fuel region characteristics expected in nuclear light bulb reactors. Argon was injected at the ends of the test chamber to provide radial-inflow vortex flow pattern. In some tests, simulated fuel consisting of a mixture of argon gas with either tungsten hexafluoride gas, uranium hexafluoride gas, or tungsten particles was injected into the discharge region from probes located at the centers of the end walls. The encouraging initial results obtained are discussed.

Roman, W. C.↗
DOE OSTI2023

Solution combustion synthesis of iron-based alumina catalysts for dehydrogenation of fossil fuels

Microwave-assisted thermocatalytic dehydrogenation of fossil fuels has been proposed as a method for hydrogen production with no CO2 emissions. The byproduct is carbon, which has a commercial value. Iron-based alumina nanocomposites are promising catalysts for this process as they both absorb microwave radiation and catalyze the dehydrogenation. In addition, they may have magnetic properties, which could be used for their separation from the carbon byproduct. Solution combustion synthesis (SCS) is an attractive technique for the fabrication of iron-based alumina nanocomposites because it can produce high specific surface area oxides in a facile manner. However, the effects of the heating mode, the fuel, and the iron/aluminum ratio on the combustion synthesis behavior and the product properties have not been studied yet. In the present work, the iron-based alumina nanocomposites were obtained by SCS using a hotplate, a muffle furnace, and a microwave oven. The initial mixtures were aqueous solutions of iron nitrate, aluminum nitrate, and an organic fuel. The concentrations of the two nitrates were varied in proportion to Fe:Al molar ratios of 1:2, 1:1, and 2:1. Two fuels were tested: citric acid and glycine. The combustion was less vigorous when citric acid was used as the fuel, which is explained by the lower exothermicity of the reaction. X-ray diffraction analysis of the products confirmed the formation of complex oxides of Fe and Al, specifically it detected hercynite and magnetite phases. Brunauer-Emmett-Teller surface area analysis has shown that the powders obtained using citric acid have specific surface areas as high as 276 m2/g, significantly higher than those obtained using glycine. Muffle furnace and hotplate heating led to comparable specific surface areas, while microwave heating resulted in significantly lower specific surface areas. The magnetic properties of the products increase with increasing the Fe/Al molar ratio from 1:2 (no response to a magnetic field) to 1:1 (weak response) and 2:1 (strong response).

solution combustion synthesis, nanoscale oxides, f↗
DOE OSTI2019

Fabrication and Irradiation Test Plan for Fully Ceramic Microencapsulated Fuels

The objective of this work is to irradiate fully ceramic microencapsulated (FCM) fuel in the High Flux Isotope Reactor (HFIR) to (1) facilitate irradiation of novel fuel concepts and (2) validate potential fuel performance. The FCM fuel used in this study is composed of either uranium nitride (UN) or two phase uranium oxide and uranium carbide (UCO) kernels, each of which are coated with a tristructural-isotropic (TRISO) coating layer and compacted into a silicon carbide (SiC) matrix. The TRISO layers and matrix provide multiple barriers to fission product release. Five particles are placed into the matrix and, combined, are considered a single “pellet”. This fuel concept is a candidate accident-tolerant fuel (ATF) for use in light water reactors (LWRs) and advanced reactor concepts. The potential benefits of the FCM fuel concept include greater burnup, improved fuel reliability, and improved thermal performance. The UN particles used in this fuel concept are intended to enhance heavy metal loading to achieve sustainable LWR cycle lengths. These kernels were developed and produced under the Advanced Fuels Campaign (AFC) at Oak Ridge National Laboratory (ORNL) beginning in FY15, and coating parameters for UN were completed in FY16. Production of very high-density TRISO-coated UN kernels was completed more recently in FY18. The experiment described herein is being conducted to provide basic data on the irradiation performance of these fuel pellets at relevant LWR temperatures. This report presents the irradiation test plan for this novel fuel concept.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2025

Future TRISO fuel irradiations in the Advanced Test Reactor

AGR-5/6/7 was thought to be the last experiment in the AGR series and the last experiment directly sponsored by DOE. Over the last five years three developments have caused a reevaluation of that assumption. First is that interest in TRISO fueled reactors has spiked dramatically. Virtually all of the new reactor designs are for SMRs or micro-reactors . Some of these reactors use new fuel designs with higher concentrations of U235. This results in changes to the particle design and even fuel pellet design. Second, a design flaw in AGR-5/6/7 Capsule 1 produced a large number of particle failures which resulted in the loss of data from Capsule 1. An additional irradiation could fill in this lost data set. Thirdly, many reactor developers have decided to use AGR spec fuel but different irradiation goals have been identified.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

INL transient reactor restart progress

The United States Department of Energy (DOE) has authorized resumption of transient testing and the restart of the Transient Reactor Test (TREAT) facility. The TREAT reactor was used from 1959 to 1994 to conduct more than 2800 nuclear fuel transient tests prior to being placed in standby in 1994. The plant was extensively upgraded shortly before it was placed in standby. Present day assessments revealed that a sound infrastructure remains at the plant. The assessments included extensive walk-downs and subsequent functional testing. The testing was broad in scope, but ensured that any plant operability issues, including age related degradation were discovered and resolved. The primary age related degradation found was capacitors in Reactor Trip System and Automatic Reactor Control System power supplies. The majority of low voltage power supplies required replacement. Although minimal degradation was evident, in some cases elastomers such as hydraulic hoses were preemptively replaced to take advantage of the existing maintenance window and ensure future reliable operation. Configuration management has been extensively reviewed and the plant components re-labeled using modern standards. The re-labeling required extensive work including updates to plant drawings and procedures. The plant organization has been established to restart the reactor and will subsequently seamlessly transition to reactor operations. For the restart effort, the operating organization is being supplemented by subcontractors including some personnel who were involved in TREAT historical operations. During 2015 and the first half of 2016 substantial progress has been made to renew reactor systems and infrastructure, update procedures and configuration management documents, and put in place a qualified operating organization. Reactor startup is anticipated no later than 2018. (author)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2017

U.S. Light-duty Vehicle Air Conditioning Fuel Use and the Impact of Four Solar/Thermal Control Technologies

The U.S. uses 7.6 billion gallons of fuel per year for vehicle air conditioning (A/C), equivalent to 5.7 percent of the total national light-duty vehicle (LDV) fuel use. This equates to 30 gallons/year per vehicle, or 23.5 grams (g) of carbon dioxide (CO2) per mile, for an average U.S. vehicle. A/C is a significant contribution to national fuel use; therefore, technologies that reduce A/C loads may reduce operational costs, A/C fuel use, and CO2 emissions. Since A/C is not operated during standard EPA fuel economy testing protocols, EPA provides off-cycle credits to encourage OEMs to implement advanced A/C technologies that reduce fuel use in the real world. NREL researchers assessed thermal/solar off-cycle credits available in the U.S. Environmental Protection Agency's (EPA's) Final Rule for Model Year 2017 and Later Light-Duty Vehicle Greenhouse Gas Emissions and Corporate Average Fuel Economy. Credits include glazings, solar reflective paint, and passive and active cabin ventilation. Implementing solar control glass reduced CO2 emissions by 2.0 g/mi, and solar reflective paint resulted in a reduction of 0.8 g/mi. Active and passive ventilation strategies only reduced emissions by 0.1 and 0.2 g/mi, respectively. The national-level analysis process is powerful and general; it can be used to determine the impact of a wide range of new vehicle thermal technologies on fuel use, EV range, and CO2 emissions.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2015

Optimization of a dry, mixed nuclear fuel storage array for nuclear criticality safety - 14339

A dry storage array of used nuclear fuel at the Idaho National Laboratory contains a mixture of more than twenty different types of research and test reactor fuels. Significant neutronic interaction occurs between fuel canisters within this large storage arrangement of 636 fuel storage canisters. Nuclear criticality safety is maintained primarily by moderation control and through control of neutron interaction and leakage provided by the credited geometry. Over the nearly forty years of operation the collected fuels are now arranged in a configuration that does not minimize the system neutron multiplication factor (k{sub eff}). This creates a concern since the entire remaining facility storage capacity cannot be utilized without exceeding the system minimum subcritical state (k{sub safe}) for ensuring nuclear criticality safety. This work determines a more optimal arrangement for the stored fuels with a goal to minimize the system k{sub eff}, but also with a minimum of potential fuel canister relocation movements. The ultimate goal is to establish a solution for this multiple-objective optimization problem by finding the Pareto Front for maximum k{sub eff} reduction versus the number of canister relocations. The process first required additional analysis of the array by Monte-Carlo neutron transport codes (specifically, MCNP) to gain a greater understanding of the interaction characteristics of the disparate fuel types. Some stored fuels are composed of primarily metallic and oxide components that provide very little inherent moderation, while other fuel types contain graphite or zirconium-hydride which can contribute a significant amount of moderation. These factors cause a complex relationship within a fuel arrangement with respect to thermal utilization and axial leakage probability. The new MCNP analysis was utilized to develop a simplified spreadsheet-based empirical model which simulates the array k{sub eff} result. This empirical model was benchmarked against additional MCNP calculations for various arrangements and then employed in the optimization analysis. A Tabu metaheuristic and stochastic approximation optimization was applied to the empirical model with the optimization function to minimize the array k{sub eff}. The optimization algorithm interrogated the empirical model to determine the optimal rearrangement for up to sixty canister movements. The Pareto Front was found, which shows that a limited number of canister relocation movements could allow the existing thirty-one empty array positions to be filled with common research reactor fuels while also yielding a reduction in the overall array k{sub eff} relative to the current arrangement. This will impart an improvement in the facility utilization while also offering an enhancement in the safety margin. The reduction in array reactivity has been confirmed by a final set of MCNP calculations with the proposed new arrangements. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

USHPRR MP-1 Irradiation Test: Assessment of Edge Pitting and Bond Line Corrosion in Vendor Produced Fuel Plates

This report summarizes an effort to identify the source of anomalous localized edge pitting and bond line corrosive attack of experimental mini fuel plates manufactured at the commercial fuel vendor BWXT and tested in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) as part of the Miniplate 1 (MP-1) irradiation test. The MP-1 test was conducted by the US High Performance Research Reactor Project (USHPRR) and overseen by the Fuel Qualification Pillar (FQ). The test involved evaluation of a mix of 62 “vendor” fuel plates fabricated at BWXT and 12 “laboratory” fuel plates fabricated at Idaho National Laboratory using commercial-scale and labscale fabrication processes respectively. The MP-1 test was the first in a series of tests to generate data to support qualification of a new plate-type low-enriched uranium (LEU) U-10Mo monolithic fuel system. The major objective of the MP-1 experiment was to test, for the first time, miniplates fabricated by a commercial fuel vendor over the range of irradiation conditions relevant to conversion of NRC regulated High Performance Research Reactors (HPRRs) from high-enriched uranium to LEU. The focus of the efforts described in this report are the vendor fuel plates to inform changes in the fabrication process prior to fabrication of the next miniplate experiment MP2.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS2013

Thermal Stability Results of a Fischer-Tropsch Fuel With Various Blends of Aromatic Solution

Fischer-Tropsch (F-T) jet fuel composition differs from petroleum-based, conventional commercial jet fuel because of differences in feedstock and production methodology. F-T fuel typically has a lower aromatic and sulfur content and consists primarily of iso and normal paraffins. The ASTM D3241 specification for Jet Fuel Thermal Oxidation Test (JFTOT) break point testing method was used to test the breakpoint of a baseline commercial grade F-T jet fuel, and various blends of this F-T fuel with an aromatic solution. The goal of this research is to determine the effect of aromatic content on the thermal stability of F-T fuel. The testing completed in this report was supported by the NASA Fundamental Aeronautics Subsonic Fixed Wing Project. Two different aromatic content fuels from Rentech, as well as these fuels with added aromatic blend were analyzed for thermal stability using the JFTOT method. Preliminary results indicate a reduction in thermal stability occurs upon increasing the aromatic content to 10% by adding an aromatic blend to the neat fuel. These results do not specify a failure based on pressure drop, but only on tube color. It is unclear whether tube color correlates to more deposition on the tube surface or not. Further research is necessary in order to determine if these failures are true failures based on tube color. Research using ellipsometry to determine tube deposit thickness rather than color will be continued in follow-up of this study.

Lindsey, Jennifer↗
NASA NTRS2014

Raising Nuclear Thermal Propulsion (NTP) Technology Readiness Above 3

NTP development is currently supported by the NASA program office "Advanced Exploration Systems". The concept is a main propulsion option being considered for human missions to Mars in the 2030's. Major NTP development took place in the 1960's and 1970's under the Rover/NERVA program. The technology had matured to TRL 6 and was preparing to go to TRL 7 with a prototype flight engine before the program was cancelled. Over the last 40 years, a variety of continuations started, but only lasted a few years each. The Rover/NERVA infrastructure is almost all gone. The only remains are a few pieces of hardware, final reports and a few who worked the Rover/NERVA. Two types of nuclear fuel are being investigated to meet the current engine design specific impulse of 900 seconds compared to approximately 850 seconds demonstrated during Rover/NERVA. One is a continuation of composite fuel with new coatings to better control mid-band corrosion. The other type is a CERMET fuel made of Tungsten and UO2. Both fuels are being made from Rover/NERVA lessons learned, but with slightly different recipes to increase fuel endurance at higher operating temperatures. The technology readiness level (TRL) of these current modified reactor fuels is approximately TRL 3. To keep the development cost low and help mature the TRL level past 4 quickly, a few special non-nuclear test facilities have been made to test surrogate fuel, with depleted uranium, as coupons and full length elements. Both facilities utilize inductive heating and are licensed to handle depleted uranium. TRL 5 requires exposing the fuel to a nuclear environment and TRL 6 requires a prototype ground or flight engine system test. Currently, three different NTP ground test facility options are being investigated: exhaust scrubber, bore hole, and total exhaust containment. In parallel, a prototype flight demonstration test is also being studied. The first human mission to Mars in the 2030's is currently 2033. For an advanced propulsion concept to be seriously considered for use, the engine development plans need to show it is feasible and affordable to reach TRL 8 by 2027 and can be qualified for human mission use.

Gerrish, Harold P., Jr.↗
NASA NTRS2016

Thermal Propulsion Capture System Heat Exchanger Design

One of the biggest challenges of manned spaceflight beyond low earth orbit and the moon is harmful radiation that astronauts would be exposed to on their long journey to Mars and further destinations. Using nuclear energy has the potential to be a more effective means of propulsion compared to traditional chemical engines (higher specific impulse). An upper stage nuclear engine would allow astronauts to reach their destination faster and more fuel efficiently. Testing these engines poses engineering challenges due to the need to totally capture the engine exhaust. The Thermal Propulsion Capture System is a concept for cost effectively and safely testing Nuclear Thermal Engines. Nominally, hydrogen exhausted from the engine is not radioactive, but is treated as such in case of fuel element failure. The Thermal Propulsion Capture System involves injecting liquid oxygen to convert the hydrogen exhaust into steam. The steam is then cooled and condensed into liquid water to allow for storage. The Thermal Propulsion Capture System concept for ground testing of a nuclear powered engine involves capturing the engine exhaust to be cooled and condensed before being stored. The hydrogen exhaust is injected with liquid oxygen and burned to form steam. That steam must be cooled to saturation temperatures before being condensed into liquid water. A crossflow heat exchanger using water as a working fluid will be designed to accomplish this goal. Design a cross flow heat exchanger for the Thermal Propulsion Capture System testing which: Eliminates the need for water injection cooling, Cools steam from 5800 F to saturation temperature, and Is efficient and minimizes water requirement.

Richard, Evan M.↗
NASA NTRS1992

Results of Labscale Hybrid Rocket Motor investigation

This work was performed to establish a labscale hybrid rocket motor test and evaluation capability at NASA Marshall Space Flight Center. The scope included activation of a Labscale Hybrid Motor, determination of baseline burning rates for PMMA fuel, and replication of pressure oscillations for HTPB fuel. The 0.820-in.-diam port, 10-in.-long fuel grains were burned for two seconds with gaseous oxygen. PMMA fuels were tested at oxygen fluxes from 0.047 lbm/sec sq in. to 0.378 lbm/sec sq in., and the HTPB fuel was evaluated at 0.378 lbm/sec sq in. The results showed that the labscale hybrid motor replicated previously reported PMMA fuel regression rates. The results also replicated low-frequency (less than 100 Hz) pressure oscillations that have been observed for HTPB fuels. These results establish the Labscale Hybrid Motor facility at MSFC.

Greiner, B.↗
NASA NTRS1982

Advanced ceramic coating development for industrial/utility gas turbines

A program was conducted with the objective of developing advanced thermal barrier coating (TBC) systems. Coating application was by plasma spray. Duplex, triplex and graded coatings were tested. Coating systems incorporated both NiCrAly and CoCrAly bond coats. Four ceramic overlays were tested: ZrO2.82O3; CaO.TiO2; 2CaO.SiO2; and MgO.Al2O3. The best overall results were obtained with a CaO.TiO2 coating applied to a NiCrAly bond coat. This coating was less sensitive than the ZrO2.8Y2O3 coating to process variables and part geometry. Testing with fuels contaminated with compounds containing sulfur, phosphorus and alkali metals showed the zirconia coatings were destabilized. The calcium titanate coatings were not affected by these contaminants. However, when fuels were used containing 50 ppm of vanadium and 150 ppm of magnesium, heavy deposits were formed on the test specimens and combustor components that required frequent cleaning of the test rig. During the program Mars engine first-stage turbine blades were coated and installed for an engine cyclic endurance run with the zirconia, calcium titanate, and calcium silicate coatings. Heavy spalling developed with the calcium silicate system. The zirconia and calcium titanate systems survived the full test duration. It was concluded that these two TBC's showed potential for application in gas turbines.

Vogan, J. W.↗
DOE OSTI2019

U.S. HIGH PERFORMANCE RESEARCH REACTOR PRELIMINARY DESIGN MILESTONE FOR CONVERSION TO LOW ENRICHED URANIUM FUEL

The U.S. reactors that regularly refuel with highly enriched uranium (HEU) have undertaken conversion to low-enriched uranium (LEU) using a high-density alloy of uranium-10 wt% molybdenum (U-10Mo) that is under development for the U.S. High Performance Research Reactors (USHPRR). The U.S. National Nuclear Security Administration (NNSA) Material Management and Minimization (M3) Reactor Conversion Program is pursuing USHPRR conversion. The USHPRR consists of nine national laboratories and three universities working with a uranium processing plant and commercial fuel fabricator to convert five reactors and an associated critical assembly. Feasibility designs were completed in 2009 for all USHPRR. Since then, the USHPRR have completed key milestones leading to preliminary designs. Between 2007 and 2011, the Fuel Qualification (FQ) Pillar conducted seven irradiation campaigns consisting of 14 large size plates and over 60 mini plates with U-10Mo fuel with a zirconium interlayer. The Preliminary Report on U-Mo Monolithic Fuel for Research Reactors submitted for review to the U.S. Nuclear Regulatory Commission (NRC) in 2017 summarizes these irradiation tests. The Fuel Fabrication (FF) Pillar has installed and is operating a fabrication pilot line at BWX Technologies, Inc. In tandem, the Reactor Conversion (RC) Pillar, has been working with each USHPRR to mature conversion designs and to include recent data. As of 2018, all five USHPRR have completed LEU designs. This includes three Preliminary Safety Analysis Reports (PSARs) submitted between 2014 and 2017 to the NRC by the National Institute of Standards and Technology, University of Missouri, and Massachusetts Institute of Technology for their reactors NBSR, MURR, and MITR, respectively. In 2018, the two USHPRR reactors regulated by the U.S. Department of Energy (DOE) at Idaho National Laboratory (ATR) and Oak Ridge National Laboratory (HFIR) completed optimized conceptual or preliminary designs, with ATR confirming a ‘base fuel’ design of the same fabrication complexity as required for MURR, MITR and NBSR. Instead of available U-10Mo designs, HFIR is pursuing a longer silicide (U3Si2) fuel design with a fuel meat density of 4.8 gU/cm3. However, HFIR conversion will require additional fuel qualification due to the complex fuel design containing boron and since HFIR exceeds existing silicide qualification limits. These preliminary designs allow for a commercial fabrication demonstration, and subsequent irradiation qualification of these fuel element designs in order to complete final SARs that allow for USHPRR conversion to LEU fuel.

Wilson, E. H.↗
DOE OSTI2023

Analysis of Uncertainty Impacts on Emissions and Fuel Economy Evaluation for Chassis Dynamometer Testing

This study illustrates a methodology for quantifying the uncertainties encountered in the measurement of tailpipe emissions and in the fuel consumption measurements for light-duty conventional vehicles tested on a four-wheel drive chassis dynamometer. The study leverages high-fidelity experimental data collected over three standard drive cycles, UDDS, HWY and US06, intended to simulate a wide range of operating conditions. Here, a method is developed to estimate the measurement uncertainties in fuel consumption for a test cycle, which occur due to the accumulation of measurement uncertainties propagated through the system. The uncertainty determination model uses statistical analysis and standard propagation techniques to evaluate and combine the uncertainties introduced from various sources (including the vehicle, chassis dynamometer, driver, and instrumentation). The analysis also examines three different experimental methods for determining the fuel consumption: 1) carbon mass balance, 2) volumetric fuel scale and 3) gravimetric fuel scale, and takes into consideration the properties of the instrumentation used. The results show that the most significant influence on the determination of the emissions comes from the concentration measurement, and similarly the biggest impact on the total fuel consumption uncertainty comes from the uncertainty in the determination of the carbon dioxide mass, due to the large presence of this pollutant in the overall emissions. It was found that the fuel consumption uncertainties are in the range of ±1-2% for all three methods analyzed, with the lowest values being obtained for measurements performed using the gravimetric method for all three drive cycles considered.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2018

Assessment of failure modes of monolithic fuel plates

Monolithic fuel is a fuel form that is considered for the conversion of high performance research reactors. In order to qualify this new fuel system, the fuel plates should meet the safety standards and perform well in reactor. The fuel system must maintain its mechanical integrity, sustain a geometric stability and should have stable and predictable irradiation behavior. The requirement to maintain mechanical integrity under normal operating conditions is primarily demonstrated by a successful testing of fuel plates up to the limiting conditions defined by the fuel performance envelope, including an adequate margin. Although large number of plates have been tested with satisfactory thermo-mechanical performance, post-irradiation examination of plates from previous RERTR-12 experiments have revealed that pillowing occurred in several plates, rendering performance of these plates unacceptable. To address such failures, efforts are underway to define the mechanisms responsible for the in-reactor pillowing, and suggest improvements to the fuel plate design and operational envelope. For this purpose, selected plates from previous experiments were simulated to understand the thermo-mechanical response of the plates to the fission density and thermally induced stresses. Simulation results were then comparatively evaluated with post-irradiation examinations of selected plates. The simulation results and experimental observations established a possible correlation between failure by plate pillowing, high porosity and a presence of tensile stress state. The study has implied that porosity leading to degradation of material properties, accompanied by a sufficiently large tensile stress state can lead to a pillowing-type failure at reactor shutdown. This paper presents these findings, discusses such failure modes, and the influence of fuel burn-up and power on the magnitude of the shutdown-induced tensile stresses.

42 ENGINEERING↗