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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

High-energy synchrotron study of in-pile-irradiated U–Mo fuels

Here synchrotron scattering analysis results on U–7wt.%Mo fuel specimens irradiated in the Advanced Test Reactor to three burnup levels (3.0, 5.2, and 6.3 × 1021 fission/cm3) are reported. Mature fission gas bubble superlattice was observed to form at intermediate burnup. The superlattice constant was determined to be 11.7 and 12.0 nm by wide-angle and small-angle scattering respectively. Grain sub-division takes place throughout the irradiation and causes the collapse of the superlattice at high burnup. The bubble superlattice expands the U–Mo lattice and acts as strong sink for radiation-induced defects. The evolution of dislocation loops was, therefore, suppressed until the bubble superlattice collapsed.

metallic nuclear fuel↗
DOE OSTI2018

EISA (Energy Independence and Security Act) compliant ethanol fuel from corn stover in a depot-based decentralized system

Cellulosic biofuels face significant problems of feedstock aggregation and logistics leading to poor economies of scale. The current model is based on relatively small biorefineries using locally-gathered feedstocks. Here, we examine the potential capacity of a hypothetically distributed, depot-based, biorefinery system to produce cellulosic ethanol from corn stover in the United States Midwest. The local depots serve to aggregate, pretreat and densify biomass (via pellets), which are collected, transported, and fed to a few very large, cellulosic ethanol biorefineries. We found that a corn stover-based depot system would help establish one or two very large-scale biorefineries capable of processing about 8-12% of total corn stover available in the United States Midwest. About 55-153 depots could supply the pretreated pellets to each distributed biorefinery leading to an annual production of 1.02 - 2.91 billion liters of cellulosic ethanol. Most of the participating depots would be located in Illinois and Iowa. The ethanol selling price in this depot-based biorefinery system would varys between U$S 0.67 and U$S 0.72 liter-1. The estimated range of GHG savings from cellulosic ethanol in the depot system compared to gasoline was 3.35-4.84 Tg CO2 year-1. In addition of being economically competitive, a distributed, depot-based, biorefinery system could meet the 60% GHG reduction requirement of the U.S. Energy Independence and Security Act (EISA).

Biorefinery, Cellulosic biofuel, Corn stover, Dist↗
DOE OSTI2021

Catalytic Hydroprocessing of Single-Cell Oils to Hydrocarbon Fuels : Converting microbial lipids to fuels is a promising approach to replace fossil fuels

Microbial lipids hold great promise as biofuel precursors, and research efforts to convert such lipids to renewable diesel fuels have been increasing in recent years. In contrast to the numerous literature reviews on growing, characterising and extracting lipids from oleaginous microbes, and on converting vegetable oils to hydrocarbon fuels, this review aims to provide insight into aspects that are specific to hydroprocessing microbial lipids. While standard hydrotreating catalysts generally perform well with terrestrial oils, differences in lipid speciation and the presence of co-extracted compounds, such as chlorophyll and sterols, introduce additional complexities into the process for microbial lipids. Lipid cleanup steps can be introduced to produce suitable feedstocks for catalytic upgrading.

09 BIOMASS FUELS↗
DOE OSTI2013

Nuclear fuel assemblies and fuel debris monitor for characterization of fuel assemblies for final storage

NUKEM monitor FAMOS is designed to measure the burn up of fuel assemblies (FA's) and allows the calculation of the content of fissile material and other actinides. The knowledge of the isotopic composition and activities of FA's is required for a safe handling and storage of the elements. The monitor analyses the measurement results on the basis of burn up calculations which improve the quality of the results, with respect to previous systems, which did not use those. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

U.S. energy sector impacts of technology innovation, fuel price, and electric sector CO2 policy: Results from the EMF 32 model intercomparison study

We study the impact of fuel prices, technology innovation, and a CO2 emissions reduction policy on both the electric power and end-use sectors by comparing outputs from four U.S. energy-economic models through the year 2050. Achieving innovation goals decreases CO2 emissions in all models, regardless of natural gas price, due to increased energy efficiency and low-carbon generation becoming more cost competitive. For the models that include domestic natural gas markets, achieving innovation goals lowers wholesale electricity prices, but this effect diminishes as projected natural gas prices increase. Higher natural gas prices lead to higher wholesale electricity prices but fewer coal capacity retirements. A CO2 electric power sector emissions cap influences electric sector evolution under reference technology assumptions but has little to no incremental influence when added to innovation goals. Long-term, meeting innovation goals achieves a generation mix with similar CO2 emissions compared to the CO2 policy but with smaller increases to wholesale electricity prices. In the short-term, the relative effect on wholesale prices differs by model. Finally, higher natural gas prices, achieving innovation goals, and the combination of the two, increases the amount of renewable generation that is cost-effective to build and operate while slowing the growth of natural-gas fired generation, which is the predominant generation type in 2050 under reference conditions.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2016

Thrust I Fuel Merit Function: A Tool for Ranking Fuel-Enabled Efficiency Gains When Multiple Fuel Properties Vary Simultaneously

This is one of a series of reports produced as a result of the Co-Optimization of Fuels & Engines (Co-Optima) project, a Department of Energy (DOE)-sponsored multi-agency project initiated to accelerate the introduction of affordable, scalable, and sustainable biofuels and high-efficiency, low-emission vehicle engines. The simultaneous fuels and vehicles research and development is designed to deliver maximum energy savings, emissions reduction, and on-road performance.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2020

Gasoline Engine and Fuels Offering Reduced Fuel Consumption and Emissions: Vehicle Modeling Final Report

The Gasoline Engine and Fuels Offering Reduced Fuel Consumption and Emissions (GEFORCE) project was proposed in response to the U.S. Department of Energy’s Funding Opportunity Announcement 0991 by a team made up of the members of the Coordinating Research Council (CRC) and the research staff at Oak Ridge National Laboratory (ORNL.) The project focused on investigating the potential benefits that might be attained through synergistic use of specific engine technology together with fuels formulated to represent potential directions that high-octane fuels of the future might progress. A stated objective in the DOE FOA was to demonstrate a 25% reduction in petroleum consumption through optimization of the engine technologies together with a suitable fuel. An advanced engine was constructed and used with a matrix of research fuels to investigate potential avenues for efficiency improvement. The engine incorporated technologies expected to become mainstream for boosted engines in the next 10 to 20 years. These included increased compression ratio, a two-stage turbocharger, and cooled external exhaust gas recirculation (EGR). The fuel matrix was designed to investigate impacts from research octane number (RON), volumetric ethanol content, and the final boiling point of the fuel. The engine calibration was optimized for each fuel individually and data collected to enable vehicle system modelling that projected energy consumption, fuel economy, tailpipe CO₂ emissions, and impact on petroleum consumption for an industry-average mid-size sedan. The engine calibration and data collection were carried out at IAV in Michigan and is the subject of a separate report. IAV provided the engine data to Oak Ridge National Laboratory to support the vehicle modelling portion of the project. The vehicle modelling results show the following trends: Ethanol content does have a consistently strong influence on the fuel economy results for all cycles and all fuels. Among the fuels of a nominal RON level, increasing ethanol content consistently lowers fuel economy, with the 30% ethanol fuels always providing the lowest fuel economy for a given RON level. However, in some cases the energy consumption improvement allows the 30% ethanol fuels to match the fuel economy of the ethanol-free fuel P. These observations underscore the importance of both engine efficiency and fuel volumetric energy content on vehicle fuel economy.; There was no consistent trend in the projected energy consumption results for differences in fuel T90 for all fuels and cycles. Fuel economy projections did show a consistent trend, with the higher T90 fuel providing slightly greater fuel economy when compared to the low T90 fuel of the same ethanol content. The observed trends were consistent with differences in the heating value of the fuels.; The 102-RON fuels provided reduced energy consumption and greater fuel economy for the advanced engine on all drive cycles. The engine compression ratio of 11.5 was higher than would typically be used in a turbocharged engine when 92-RON fuel use is expected. Hence, the engine experiences more efficiency degradation from knock avoidance when using the 92-RON fuels. This degradation causes the fuel economy results for the 92-RON fuels to be lower than those for the 102-RON fuels.; Fuels E and F (92-RON, 30% ethanol) are projected to achieve 10% or greater reduction in petroleum consumption, with fuels K (102-RON, 30% ethanol) and O (97 RON, 30% ethanol) achieving greater than a 20% reduction. Fuel L (102-RON, 30% ethanol) achieves greater than 25% reduction, meeting the petroleum reduction target of the project. All of the fuels that achieve 10% or greater reduction in petroleum consumption are 30% ethanol blends.; Increasing final boiling point increased fuel economy at fixed ethanol content when the 102-RON fuels were used. This trend is a result of differences in the volumetric energy content of the fuels and the projected energy consumption values for the fuels. In the case of the 102-RON fuels, increasing final boiling point also resulted in an increase in the energy content of the fuel. There was not a consistent trend between the energy content and final boiling point for the 92-RON fuels at fixed ethanol content.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2019

Single-Fuel Reactivity Controlled Compression Ignition Combustion Enabled by Onboard Fuel Reformation (Final Report)

Reactivity-Controlled Compression Ignition (RCCI) is a promising new advanced, low temperature combustion mode that offers efficiencies equal to or greater than conventional diesel combustion, but significantly lower soot and NOx emissions. Additionally, RCCI has enhanced controllability over the combustion process compared to some of the other advanced combustion modes. Therefore, RCCI combustion has the potential to be of great benefit to the public by increasing the efficiency and reducing the harmful pollutant emissions from transportation. However, RCCI combustion achieves this favorable level of performance through the use of two distinct fuels (e.g., diesel and gasoline, diesel and natural gas, or diesel and ethanol). In a vehicle application, RCCI therefore requires two different fuel tanks and fuel injection systems, which presents a significant drawback to the commercialization RCCI. This project proposed a new concept to enable RCCI combustion from a single parent fuel stored onboard the vehicle in a single fuel tank. Specifically, the parent fuel would be stored in the fuel tank and one branch of the fuel system would deliver the parent fuel, unaltered, to the cylinder, while a second branch of the fuel system would route the parent fuel through a fuel reformer to chemically react the fuel into a gaseous fuel mixture, called “reformate”, that has different properties from the original parent fuel. In this way, there can be two fuels at the engine that have different properties, but only one parent fuel needs to be stored and refilled in the vehicle. This initial, exploratory investigation into the feasibility of this promising new concept included reacting three potential parent fuels (diesel, gasoline, and natural gas) in a fuel reformer and determining the composition of the gaseous reformate fuel that exited the fuel reformer. There are different types of reformation processes, but since this project was a proof-of-concept investigation into the potential of Single-Fuel RCCI and the combustion process in the cylinder, a catalytic partial oxidation (CPOX) reformation process was selected, which is more straightforward to perform and control, and would potentially be easier to implement in a vehicle application compared to other reformation processes. Once the three parent fuels were reformed to varying degrees and their reformate compositions were determined, their autoignition tendencies were experimentally determined by comparing advanced combustion results of the reformate mixtures with known reference fuels. This showed that diesel fuel and its reformate fuel mixture exhibited the largest reactivity separation, which is necessary to enable RCCI combustion in the cylinder. Using diesel fuel as the parent fuel, experimental testing was conducted to provide a better understanding of the operational considerations, benefits, and drawbacks of Single-Fuel RCCI with onboard fuel reformation. The experimental testing was accompanied by computational fluid dynamics and system-level modeling to help complement the experiments and further expand the understanding. The main conclusions are that Single-Fuel RCCI using diesel fuel as the direct injected, high reactivity fuel and diesel’s gaseous reformate mixture as the premixed, low reactivity fuel is viable. The efficiencies were equal to, or sometimes greater than, RCCI with conventional fuel pairs, and the emissions were comparable as well. A key consideration is that gaseous reformate fuel contains a large amount of diluents in the fuel which displace air entering the cylinder and act as EGR inside the cylinder. Additionally, the reactivity separation between diesel and its reformate fuel mixture is larger than diesel-gasoline, but less than diesel-natural gas, and the combustion process therefore responded in a manner that was between the two conventional fuel pairs. Finally, although achievable in the cylinder, there are practical drawbacks or other disadvantages of Single-Fuel RCCI with onboard fuel reformation. First, this project used a CPOX reformation process which is exothermic, meaning that a portion of the fuel’s energy was released in the reformer where it could not be converted into useful work. This constituted an efficiency penalty of the system of on the order of 10% or 4 percentage points. Future research should therefore focus on alternate reforming processes including steam-methane reforming or autothermal reforming where there might not be any energy released in the reformer, or there could even be an energy gain in the reformer (through an endothermic process with waste heat recovery). Practical drawbacks that exist, but were beyond the scope of this preliminary proof-of-concept research project, are the added cost of the fuel reformer, which is a catalyst made of precious metals, transient response of the system, and the lifetime of the fuel reformer.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2020

Drop Analysis of the Advanced Test Reactor Fresh Fuel Shipping Container with Heavier Low-Enriched Uranium Fuel Contents

The Advanced Test Reactor Fresh Fuel Shipping Container (ATR FFSC) is a rectangular stainless steel container used for shipping radioactive material. The container is described in the ATR FFSC Safety Analysis Report (SAR). Per the ATR FFSC SAR, the ATR FFSC is designated a Type AF-96 packaging per the definition of 10 CFR §71.4, and was originally designed to transport high enriched uranium (HEU) reactor fuel elements for the Advanced Test Reactor (ATR), the Advanced Test Reactor Critical (ATRC) facility, the Massachusetts Institute of Technology Reactor (MITR), and the University of Missouri Research Reactor (MURR). The Department of Energy, National Nuclear Security Administration’s (NNSA), Office of Material Management and Minimization (M3) is working with the Idaho National Laboratory (INL) to develop and qualify new low enriched uranium (LEU) fuels and technologies for use in the ATR, ATRC, MITR, and MURR reactors. The LEU fuel elements will weigh significantly more than the current HEU designs and, combined with their associated Fuel Handling Enclosures for packaging, some configurations will exceed the 50 lbf used in the ATR FFSC qualifying drop tests. There are LEU versions of MITR, MURR, and ATR fuel elements. However, for this evaluation, drop analysis of the ATR FFSC with only the heavier ATR Low Enrichment (LOWE) fuel element is considered in this evaluation because the LOWE fuel element is the heaviest of the considered LEU fuel elements. The ATR HEU fuel element and the ATR LOWE fuel element are identical in every design aspect except for the fuel meat inside the 19 fuel plates. The LEU fuel meats are made using a U-10Mo high-density foil rather than uranium dispersed in aluminum in the HEU fuel elements. The high density of the uranium in the LEU fuel meat increases the LOWE fuel element weight to just under 44 lbf (versus the 22.1 lbf weight of the tested ATR HEU fuel element). ATR fuel elements are placed in a thin-gauge aluminum weldment called a "Fuel Handling Enclosure" during packaging. The Fuel Handling Enclosure is used to cover and protect the element during loading and unloading operations. The ATR Fuel Handling Enclosure weighs about 15 lbf per the drawings in the ATR FFSC SAR and the weight is accounted for in this evaluation. Transporting the heavier LEU fuel elements require evaluation of two issues. The first is the effect of the increased mass of the LEU fuel elements on the survivability of the ATR FFSC package following the requisite drop qualifications. The second is the effect of the increased mass of the fuel plates on the fuel element during the same drops. The ATR FFSC containing an ATR HEU fuel element in an ATR Fuel Handling Enclosure was physically dropped multiple times to qualify the container as a Type AF-96 package. The ATR FFSC SAR describes the drop tests performed with an actual ATR HEU fuel element weighing 22.1 lbf contained in a 14.3 lbf Fuel Handling Enclosure for a total payload of 36.4 lbf. Those drop tests showed that the ATR FFSC maintained containment of the ATR HEU fuel element and the fuel element was not significantly damaged. (Containment herein is not defined as a leak tight but is retention of the radioactive contents.) The purpose of the evaluation is to analytically show that, for a similar set of tests, the ATR FFSC maintains containment of the heavier ATR LOWE fuel element and to assess the damage to the fuel element during the drops. The approach was to create finite element analysis (FEA) models that produce the same results as the physical drops. Those models were then used as the benchmarks for the follow-on analyses using the heavier contents. FEA models of the drops of ATR FFSC using up to a 115 lbf fuel element were run and evaluated. Likewise, drops of a LOWE fuel element weighing 44 lbf in the ATR FFSC were run and evaluated. It is important to note that this report was done at the quality level necessary to be included in a nuclear facility safety basis. However, it is not the intent of this report to conclude the suitability of the ATR FFSC for transporting the heavier payloads. This report only describes the results of the FEA as related to the required drop scenarios. Incorporation of the FEA into the safety basis will be evaluated by the ATR FFSC design authority. The physical drop tests of the HEU fuel element and FEA drop analysis for the LOWE fuel element showed noteworthy damage to the fuel plates. An aluminum protective block was conceived to mitigate the damage. The concept requires the blocks to be placed in the fuel element between the end boxes and fuel plates. Additional FEA drop analyses were performed using the protective block. The addition of the blocks is primarily intended to mitigate the damage to the LOWE fuel element fuel plates. However, FEA drop analyses of the ATR HEU fuel element with the blocks were also performed and included for information.

42 ENGINEERING↗
DOE OSTI2023

Engine Operating Conditions, Fuel Property Effects, and Associated Fuel–Wall Interaction Dependencies of Stochastic Preignition

This work for the Coordinating Research Council (CRC) explores dependencies on the opportunity for fuel to impinge on internal engine surfaces (i.e., fuel–wall impingement) as a function of fuel properties and engine operating conditions and correlates these data with measurements of stochastic preignition (SPI) propensity. SPI rates are directly coupled with laser–induced florescence measurements of dye-doped fuel dilution measurements of the engine lubricant, which provides a surrogate for fuel–wall impingement. Literature suggests that SPI may have several dependencies, one being fuel–wall impingement. However, it remains unknown if fuel-wall impingement is a fundamental predictor and source of SPI or is simply a causational factor of SPI. In this study, these relationships on SPI and fuel-wall impingement are explored using 4 fuels at 8 operating conditions per fuel, for 32 total test points. The fuels were directly injected at two different injection timings: an earlier injection timing that initially targets the piston crown and a later injection timing that targets the cylinder liner. At each injection timing, the engine was operated at both 90°C and 70°C coolant and lubricant temperatures, and 185 and 200 kPa absolute intake manifold pressure. This work serves as an exploratory effort to down select conditions and provide initial fuel properties of interest for a secondary study to explore fuel property specific effects on fuel-wall interaction and SPI propensity. Significant findings from this initial operating condition and fuel property exploratory work are: 1. reduced engine operating coolant and lubricant temperatures, along with 2. retarded injection timings were required to increase SPI propensity. Moreover, at these conditions some fuel specific effects were also observed; specifically, increased ethanol content increased measured dye–wall (i.e., fuel–wall) interaction. However, despite increased dye–wall interaction, the increased volatility of the ethanol containing fuels also reduced the estimated fuel retention in the top-ring zone and associated measured SPI propensity. Thus, the findings of this unique approach to explore relationships between fuel-wall impingement and SPI highlight that SPI propensity is more directly proportional to retained fuel, and not simply fuel–wall impingement. Furthermore, fuel retention was found to be directly influenced by complex fuel property and engine operating condition relationships. Either retarded injection timings and/or increased fuel volatility increased fuel wall-impingement, while less volatile fuels and/or reduced coolant temperatures increased fuel retention. Therefore, for a given operating condition, the data highlights that greater volatile fuels exhibit increased fuel wall impingement without increased fuel retention or SPI propensity, while less volatile fuels could exhibit reduced fuel-wall impingement but increased fuel retention and SPI propensity rates.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2014

Irradiation performance of U-Mo monolithic fuel

High-performance research reactors require fuel that operates at high specific power to high fission density, but at relatively low temperatures. Research reactor fuels are designed for efficient heat rejection, and are composed of assemblies of thin-plates clad in aluminum alloy. The development of low-enriched fuels to replace high-enriched fuels for these reactors requires a substantially increased uranium density in the fuel to offset the decrease in enrichment. Very few fuel phases have been identified that have the required combination of very-high uranium density and stable fuel behavior at high burnup. U-Mo alloys represent the best known tradeoff in these properties. Testing of aluminum matrix U-Mo aluminum matrix dispersion fuel revealed a pattern of breakaway swelling behavior at intermediate burnup, related to the formation of a molybdenum stabilized high aluminum intermetallic phase that forms during irradiation. In the case of monolithic fuel, this issue was addressed by eliminating, as much as possible, the interfacial area between U-Mo and aluminum. Based on scoping irradiation test data, a fuel plate system composed of solid U-10Mo fuel meat, a zirconium diffusion barrier, and Al6061 cladding was selected for development. Developmental testing of this fuel system indicates that it meets core criteria for fuel qualification, including stable and predictable swelling behavior, mechanical integrity to high burnup, and geometric stability. In addition, the fuel exhibits robust behavior during power-cooling mismatch events under irradiation at high power.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2012

Texas Hydrogen Highway Fuel Cell Hybrid Bus and Fueling Infrastructure Technology Showcase (Final Scientific/Technical Report)

The Texas Hydrogen Highway project has showcased a hydrogen fuel cell transit bus and hydrogen fueling infrastructure that was designed and built through previous support from various public and private sector entities. The aim of this project has been to increase awareness among transit agencies and other public entities on these transportation technologies, and to place such technologies into commercial applications, such as a public transit agency. The initial project concept developed in 2004 was to show that a skid-mounted, fully-integrated, factory-built and tested hydrogen fueling station could be used to simplify the design, and lower the cost of fueling infrastructure for fuel cell vehicles. The approach was to design, engineer, build, and test the integrated fueling station at the factory then install it at a site that offered educational and technical resources and provide an opportunity to showcase both the fueling station and advanced hydrogen vehicles. The two primary technology components include: Hydrogen Fueling Station: The hydrogen fueling infrastructure was designed and built by Gas Technology Institute primarily through a funding grant from the Texas Commission on Environmental Quality. It includes hydrogen production, clean-up, compression, storage, and dispensing. The station consists of a steam methane reformer, gas clean-up system, gas compressor and 48 kilograms of hydrogen storage capacity for dispensing at 5000 psig. The station is skid-mounted for easy installation and can be relocated if needed. It includes a dispenser that is designed to provide temperature compensated fills using a control algorithm. The total station daily capacity is approximately 50 kilograms. Fuel Cell Bus: The transit passenger bus built by Ebus, a company located in Downey, CA, was commissioned and acquired by GTI prior to this project. It is a fuel cell plug-in hybrid electric vehicle which is ADA compliant, has air conditioning sufficient for Texas operations, and regenerative braking for battery charging. It uses a 19.3 kW Ballard PEM fuel cell, will store 12.6 kg of hydrogen at 350 Bar, and includes a 60 kWh battery storage system. The objectives of the project included the following: (a) To advance commercialization of hydrogen-powered transit buses and supporting infrastructure; (b) To provide public outreach and education by showcasing the operation of a 22-foot fuel cell hybrid shuttle bus and Texas first hydrogen fueling infrastructure; and (c) To showcase operation of zero-emissions vehicle for potential transit applications. As mentioned above, the project successfully demonstrated an early vehicle technology, the Ebus plug-in hybrid fuel cell bus, and that success has led to the acquisition of a more advanced vehicle that can take advantage of the same fueling infrastructure. Needed hydrogen station improvements have been identified that will enhance the capabilities of the fueling infrastructure to serve the new bus and to meet the transit agency needs. Over the course of this project, public officials, local government staff, and transit operators were engaged in outreach and education activities that acquainted them with the real world operation of a fuel cell bus and fueling infrastructure. Transit staff members in the Dallas/Ft. Worth region were invited to a workshop in Arlington, Texas at the North Central Texas Council of Governments to participate in a workshop on hydrogen and fuel cells, and to see the fuel cell bus in operation. The bus was trucked to the meeting for this purpose so that participants could see and ride the bus. Austin area transit staff members visited the fueling site in Austin to be briefed on the bus and to participate in a fueling demonstration. This led to further meetings to determine how a fuel cell bus and fueling station could be deployed at Capital Metro Transit. Target urban regions that expressed additional interest during the project in response to the outreach meetings and showcase events include San Antonio and Austin, Texas. In summary, the project objectives were achieved in the following ways: Through presentations and papers provided to a variety of audiences in multiple venues, the project team fulfilled its goal of providing education and outreach on hydrogen technology to statewide audiences. The project team generated interest that exists well beyond the completion of the project, and indeed, helped to generate financial support for a subsequent hydrogen vehicle project in Austin. The University of Texas, Center for ElectroMechanics operated the fuel cell-electric Ebus vehicle for over 13,000 miles in Austin, Texas in a variety of routes and loading configurations. The project took advantage of prior efforts that created a hydrogen fueling station and fuel cell electric-hybrid bus and continued to verify their technical foundation, while informing and educating potential future users of how these technologies work.

03 NATURAL GAS↗
DOE OSTI2013

Preliminary Examination of Ethanol Fuel Effects on EPA’s R-factor for Vehicle Fuel Economy

The U.S. Department of Energy (DOE) supported a test program from 2007 through 2012 to evaluate the potential impacts of intermediate ethanol blends (also known as mid-level blends) on legacy vehicles and other engines. The purpose of the program was to assess the viability of using intermediate ethanol blends as a contributor to meeting national goals for the use of renewable fuels. Appendix A lists a bibliography of related studies. The catalyst durability program involved aging and emissions testing vehicles on a range of ethanol blends. The study was completed in 2011 and a final report issued shortly after. This report describes a preliminary analysis of the fuel economy data from the catalyst durability study, to determine the proper value for the R factor which is called out in the Code of Federal Regulations (CFR) for computing vehicle fuel economy on the certification cycle. The fuel economy equation that is specified in CFR for gasoline-fuelled vehicles is based on a carbon mass balance (CMB) approach to determine the amount of fuel consumed during the test by measuring the carbon-bearing emissions that are produced; however, it also incorporates a scaling factor (R factor) based on the net heating value of the fuel and the sensitivity of fuel economy to changes in the heating value. The impact of the R factor is a fixed ratio in the resultant fuel economy that is dependent upon fuel properties other than those required for a typical CMB calculation. This equation was put in place in 1988 to correct for differences between certification fuels to address corporate average fuel economy (CAFE) credit issues associated with fuel property variations. The algorithm adjusts the calculated fuel economy to compute what would have been measured had the 1975 certification fuel been used for the test. The R factor was defined as the sensitivity of the fuel economy result to changes in fuel energy content. When R equals 1.0, the fuel economy change exactly tracks the energy density difference between the fuels. If R is less than 1.0, the fuel economy change is smaller than the change in energy density. The R factor was defined to be 0.6 based on tests using 1980s vehicles. Since that time, the Auto/Oil test program has established that the R factor for 1990s vehicles is higher (about 0.93). More recently EPA analyzed the EPAct/V2/E-89 dataset to compute the R factor, resulting in an average of 0.82 to 0.86. It is important to note that the EPAct/V2/E89 test program used the LA92 test cycle, a cycle known to contain more aggressive accelerations than the FTP. To date, EPA has only required emissions and fuel economy testing of gasoline vehicles with a certification fuel that does not contain ethanol. However in 2013 EPA issued a Proposed Rule seeking comment on the establishment of an emissions certification fuel containing ethanol, such as E10 or E15. Calculating modern vehicle fuel economy with the existing CFR equation with an R factor of 0.6 when ethanol blends are used produces significant errors. For the catalyst durability program, a straightforward CMB approach was used to compute fuel economy, thereby allowing a straightforward evaluation of the impact of ethanol content on fuel economy. However, if an ethanol-containing fuel is to become the new certification fuel for light-duty vehicles, consistent application of the CFR equation needs to be considered for the benefit of manufacturers’ CAFE compliance. Analysis of city cycle Federal Test Procedure (FTP) fuel economy test results and fuel analyses from the catalyst durability study indicates that the average R-factor for modern vehicles is very close to unity at about 0.94±0.04. This result is very similar to the results of the 1993 Auto/Oil test program. Future work should examine other drive cycles, and advanced vehicle technologies which may reveal sensitivities to properties other than heating value.

intermediate ethanol blends↗
DOE OSTI2016

Transmutation Fuels Development in the Advanced Fuels Campaign

Metallic fuels have a history of use that spans the entire nuclear age, especially in association with the development of the LMFBR. Initially, metallic fuels were employed due to their ease of fabrication and high heavy metal density (which led to the most favorable breeding efficiencies in fast reactors). During subsequent decades of use, metallic fuel technology has matured significantly, leading to the realization of major benefits in the areas of fuel reliability and burnup, proliferation-resistant recycling, remote fabrication, and passive reactor safety. Such characteristics continue to make metallic fuels a highly attractive technology, especially for use with future sodium fast reactors. Current research and development activities on metallic fuels in DOE's Advanced Fuels Campaign are focused on their potential use for actinide transmutation in advanced SFRs. In such a mission, metallic fuels would be employed as part of a closed fuel cycle into which plutonium and minor actinides (Am, Np) recovered from LWR spent fuel would be incorporated. All actinides in this metallic fuel would be fissioned or transmuted in a fast reactor to eliminate the extremely long-lived, heat-producing actinides in order to reduce the volume, heat load, and radio-toxicity burden on a future geological repository. Thus, the need exists to demonstrate reliable performance of metallic fuels with Pu and minor actinide constituents to very high burnup. As part of this application, there is also a need for a near zero-loss fabrication process, since losses during fuel fabrication are a potential source of long-lived actinides destined for geologic disposal. This paper presents the current state and future direction of the development of metallic fuels for actinide transmutation in the US. Metallic fuels have had a long history of use in sodium-cooled fast reactors. Continued research, development, and design innovation over a period of decades have demonstrated this fuel technology to be safe and reliable to extremely high burnups over a wide range of compositions. Their simple fabrication has historically given them a significant economic advantage over other fuel forms. Research and development on metallic fuels continues, with particular emphasis on showing that this fuel technology can incorporate significant quantities of plutonium and minor actinides for the purpose of efficiently and economically transmuting these elements in a fast-spectrum reactor. New fabrication methods to improve retention of the volatile fuel constituents during the casting process (and reduce waste generation), are being developed. Irradiation testing of the new metallic fuels has so far indicated that the new compositions, although differing significantly both in the quantities of Pu and minor actinides included and in the Zr alloying addition, perform as a function of fission density very analogously to the historic U-Zr and U-Pu-Zr fuels. In the next few years it is anticipated that a new casting furnace prototype will demonstrate that these new metallic fuel alloys can be fabricated at engineering scale, in a remote environment, with no significant fuel loss or waste generation. Irradiation tests currently underway will provide the performance data needed to assess fuel reliability/burnup capability and identify any unique behaviors that are a result of the new compositions. If these future results are consistent with the intermediate data available at present, metallic fuels are expected to continue to be a strong contender for the fuel technology choice of future fast reactors. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2017

Synthesis and electrochemical characterization of Ti{sub x}Ta{sub y}Al{sub z}N{sub 1-δ}O{sub γ} for fuel cell catalyst supports

Quinary Ti{sub x}Ta{sub y}Al{sub z}N{sub 1-δ}O{sub γ} of various compositions have been prepared by a co-precipitation method followed by ammonolysis. The nitride samples were examined as potential catalyst supports in polymer electrolyte membrane fuel cells. The nitride products crystallized in the rock salt (NaCl) structure over a wide range of compositions. The addition of Ta and Al was highly beneficial towards improving the chemical and electrochemical stability of TiN, without a significant loss of electrical conductivity. Platinum particles were successfully deposited on the (oxy)nitride samples, and the composite samples at some compositions were found to be comparable to Pt/carbon in their stability and catalytic activity even without optimizing the Pt deposition and dispersion processes. - Graphical abstract: The effect of additions of Ta and Al into TiN structure. Shifts the lattice constant, and increases its chemical stability in acidic environment.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗