Health effects attributable to coal and nuclear fuel cycle alternatives

International Nuclear Information System (INIS)

Gotchy, R.L.

1977-09-01

Estimates of mortality and morbidity are presented based on present-day knowledge of health effects resulting from current component designs and operations of the fuel cycles, and anticipated emission rates and occupational exposure for the various fuel cycle facilities expected to go into operation in approximately the 1975-1985 period. It was concluded that, although there are large uncertainties in the estimates of potential health effects, the coal fuel cycle alternative has a greater health impact on man than the uranium fuel cycle. However, the increased risk of health effects for either fuel cycle represents a very small incremental risk to the average individual in the public

Fuel property effects on Navy aircraft fuel systems

Science.gov (United States)

Moses, C. A.

1984-01-01

Problems of ensuring compatibility of Navy aircraft with fuels that may be different than the fuels for which the equipment was designed and qualified are discussed. To avoid expensive requalification of all the engines and airframe fuel systems, methodologies to qualify future fuels by using bench-scale and component testing are being sought. Fuel blends with increasing JP5-type aromatic concentration were seen to produce less volume swell than an equivalent aromatic concentration in the reference fuel. Futhermore, blends with naphthenes, decalin, tetralin, and naphthalenes do not deviate significantly from the correlation line of aromatic blends, Similar results are found with tensile strenth and elongation. Other elastomers, sealants, and adhesives are also being tested.

Effect of different fuel options on performance of high-temperature PEMFC (proton exchange membrane fuel cell) systems

International Nuclear Information System (INIS)

Authayanun, Suthida; Saebea, Dang; Patcharavorachot, Yaneeporn; Arpornwichanop, Amornchai

2014-01-01

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) have received substantial attention due to their high CO (carbon monoxide) tolerance and simplified water management. The hydrogen and CO fractions affect the HT-PEMFC performance and different fuel sources for hydrogen production result in different product gas compositions. Therefore, the aim of this study is to investigate the theoretical performance of HT-PEMFCs fueled by the reformate gas derived from various fuel options (i.e., methane, methanol, ethanol, and glycerol). Effects of fuel types and CO poisoning on the HT-PEMFC performance are analyzed. Furthermore, the necessity of a water-gas shift (WGS) reactor as a CO removal unit for pretreating the reformate gas is investigated for each fuel type. The methane steam reforming shows the highest possibility of CO formation, whereas the methanol steam reforming produces the lowest quantity of CO in the reformate gas. The methane fuel processing gives the maximum fraction of hydrogen (≈0.79) when the WGS reactor is included. The most suitable fuel is the one with the lowest CO poisoning effect and the maximum fuel cell performance. It is found that the HT-PEMFC system fueled by methanol without the WGS reactor and methane with WGS reactor shows the highest system efficiency (≈50%). - Highlights: • Performance of HT-PEMFC run on different fuel options is theoretically investigated. • Glycerol, methanol, ethanol and methane are hydrogen sources for the HT-PEMFC system. • Effect of CO poisoning on the HT-PEMFC performance is taken into account. • The suitable fuel for HT-PEMFC system is identified regarding the system efficiency

Effects of UO2 fuel microstructure and density on fuel in-reactor performance

International Nuclear Information System (INIS)

Hansson, L.

1988-02-01

The volume changes of UO 2 fuel pellets, produced by neutron irradiation, can be characterized by two processes: fission spike induced densification through pore skrinkage and later fission produced induced swelling of UO 2 matrix. In-pile densification is controlled by the initial density and microstructure of the fuel, particularly by the pore size distribution. The extent of swelling depends mainly on the amount of fission products produced, but the fission gas release as well as the swelling may be reduced by increasing the grain size of UO 2 . Fabrication of fuel pellets having certain in-reactor properties requires detailed knowledge of the effects of individual fabrication parameters. The irradiation experience of fuels fabricated by using different conversion and pelletizing methods is extensive. Based on this experience, some general characteristics of stable/well-performing fuel microstructures have been summarized

Effects of alpha-decay on spent fuel corrosion behaviour

International Nuclear Information System (INIS)

Wiss, T.; Rondinella, V.V.; Cobos, J.; Wegen, D.H.; Amme, M.; Ronchi, C.

2004-01-01

An overview of results in the area of spent fuel characterization as nuclear waste is presented. These studies are focused on primary aspects of spent fuel corrosion, by considering different fuel compositions and burn ups, as well as a wide set of environmental conditions. The key parameter is the storage time of the fuel e.g. in view of spent fuel retrieval or in view of its final disposal. To extrapolate data obtainable from a laboratory-acceptable timescale to those expected after storage periods of interest have elapsed (amounting in the extreme case to geological ages) is a tough challenge. Emphasis is put on key aspects of fuel corrosion related to fuel properties at a given age and environmental conditions expected in the repository: e.g. the fuel activity (radiolysis effects), the effects of helium build-up and of groundwater composition. A wide range of techniques, from traditional leaching experiments to advanced electrochemistry, and of materials, including spent fuel with different compositions/burnups and analogues like the so-called alpha-doped UO 2 , are employed for these studies. The results confirm the safety of European underground repository concepts. (authors)

Fuel composition effect on cathode airflow control in fuel cell gas turbine hybrid systems

Science.gov (United States)

Zhou, Nana; Zaccaria, Valentina; Tucker, David

2018-04-01

Cathode airflow regulation is considered an effective means for thermal management in solid oxide fuel cell gas turbine (SOFC-GT) hybrid system. However, performance and controllability are observed to vary significantly with different fuel compositions. Because a complete system characterization with any possible fuel composition is not feasible, the need arises for robust controllers. The sufficiency of robust control is dictated by the effective change of operating state given the new composition used. It is possible that controller response could become unstable without a change in the gains from one state to the other. In this paper, cathode airflow transients are analyzed in a SOFC-GT system using syngas as fuel composition, comparing with previous work which used humidified hydrogen. Transfer functions are developed to map the relationship between the airflow bypass and several key variables. The impact of fuel composition on system control is quantified by evaluating the difference between gains and poles in transfer functions. Significant variations in the gains and the poles, more than 20% in most cases, are found in turbine rotational speed and cathode airflow. The results of this work provide a guideline for the development of future control strategies to face fuel composition changes.

Engine control techniques to account for fuel effects

Science.gov (United States)

Kumar, Shankar; Frazier, Timothy R.; Stanton, Donald W.; Xu, Yi; Bunting, Bruce G.; Wolf, Leslie R.

2014-08-26

A technique for engine control to account for fuel effects including providing an internal combustion engine and a controller to regulate operation thereof, the engine being operable to combust a fuel to produce an exhaust gas; establishing a plurality of fuel property inputs; establishing a plurality of engine performance inputs; generating engine control information as a function of the fuel property inputs and the engine performance inputs; and accessing the engine control information with the controller to regulate at least one engine operating parameter.

Effect of power variations across a fuel bundle and within a fuel element on fuel centerline temperature in PHWR bundles in uncrept and crept pressure tubes

International Nuclear Information System (INIS)

Onder, E.N.; Roubtsov, D.; Rao, Y.F.; Wilhelm, B.

2017-01-01

Highlights: • Pressure tube creep effect on fuel pin power and temperatures was investigated. • Noticeable effects were observed for 5.1% crept pressure tube. • Bundle eccentricity effect on power variations was insignificant for uncrept channels. • Difference of 112 °C was observed between top & bottom elements in 5.1% crept channel. • Not discernible fission gas release was expected with temperature difference of 112 °C. - Abstract: The neutron flux and fission power profiles through a fuel bundle and across a fuel element are important aspects of nuclear fuel analysis in multi-scale/multi-physics modelling of Pressurized Heavy Water Reactors (PHWRs) with advanced fuel bundles. Fuel channels in many existing PHWRs are horizontal. With ageing, pressure tubes creep and fuel bundles in these pressure tubes are eccentrically located, which results in an asymmetric coolant flow distribution between the top and bottom of the fuel bundles. The diametral change of the pressure tube due to creep is not constant along the fuel channel; it reaches a maximum in the vicinity of the maximum neutron flux location. The cross-sectional asymmetric positioning of fuel bundles in a crept pressure tube contributes to an asymmetric power distribution within a ring of fuel elements. Modern reactor physics lattice codes (such as WIMS-AECL) are capable of predicting the details of power distribution from basic principles. Thermalhydraulics subchannel codes (such as ASSERT-PV) use models to describe inhomogeneous power distribution within and across fuel elements (e.g., flux tilt model, different powers in different ring elements, or radial power profiles). In this work, physics and thermalhydraulics codes are applied to quantify the effect of eccentricity of a fuel bundle on power variations across it and within a fuel element, and ultimately on the fuel temperature distribution and fuel centerline temperature, which is one of the indicators of fuel performance under normal

Effects of an oxidizing atmosphere in a spent fuel packaging facility

International Nuclear Information System (INIS)

Einziger, R.E.

1991-09-01

Sufficient oxidation of spent fuel can cause a cladding breach to propagate, resulting in dispersion of fuel particulates and gaseous radionuclides. The literature for spent fuel oxidation in storage and disposal programs was reviewed to evaluate the effect of an oxidizing atmosphere in a preclosure packaging facility on (1) physical condition of the fuel and (2) operations in the facility. Effects such as cladding breach propagation, cladding oxidation, rod dilation, fuel dispersal, 14 C and 85 Kr release, and crud release were evaluated. The impact of these effects, due to oxidation, upon a spent fuel handling facility is generally predicted to be less than the impact of similar effects due to fuel rod breached during handling in an inert-atmosphere facility. Preliminary temperature limits of 240 degree C and 227 degree C for a 2-week or 4-week handling period and 175 degree C for 2-year lag storage would prevent breach propagation and fuel dispersal. Additional data that are needed to support the assumptions in this analysis or complete the database were identified

Effects of Burnable Absorbers on PWR Spent Nuclear Fuel

International Nuclear Information System (INIS)

O'Leary, P.M.; Pitts, M.L.

2000-01-01

Burnup credit is an ongoing issue in designing and licensing transportation and storage casks for spent nuclear fuel (SNF). To address this issue, in July 1999, the U.S. Nuclear Regulatory Commission (NRC), Spent Fuel Project Office, issued Interim Staff Guidance-8 (ISG-8), Revision 1 allowing limited burnup credit for pressurized water reactor (PWR) spent nuclear fuel (SNF) to be used in transport and storage casks. However, one of the key limitations for a licensing basis analysis as stipulated in ISG-8, Revision 1 is that ''burnup credit is restricted to intact fuel assemblies that have not used burnable absorbers''. Because many PWR fuel designs have incorporated burnable-absorber rods for more than twenty years, this restriction places an unnecessary burden on the commercial nuclear power industry. This paper summarizes the effects of in-reactor irradiation on the isotopic inventory of PWR fuels containing different types of integral burnable absorbers (BAs). The work presented is illustrative and intended to represent typical magnitudes of the reactivity effects from depleting PWR fuel with different types of burnable absorbers

Study of Irradiation Effect onto Uranium silicide Fuel

International Nuclear Information System (INIS)

Suparjo

1998-01-01

The irradiation effect onto the U 3 Si-Al and U 3 Si 2 -Al dispersion type of fuel element has been studied. The fuel material performs swelling during irradiation due to boehmite (Al 2 O 3 (H 2 O)) formation in which might occurs inside the meat and on the cladding surface, the interaction between the fuel and aluminium matrix that produce U(Al,Si) 3 phase, and the formation of fission gas bubble inside the fuel. At a constant fission density, the U 3 Si-Al fuel swelling is higher than that of U 3 Si 2 -Al fuel. The swellings of both fuels increase with the increasing of fission density. The difference of swelling behavior was caused by formation of large bubble gases generated from fission product of U 3 Si fuel and distributed non-uniformly over all of fuel zone. On the other hand, the U 3 Si 2 fission produced small bubble gases, and those were uniformly distributed. The growth rate of fission gas bubble in the U 3 Si fuel has shown high diffusivity, transformation into amorph material and thus decrease its mechanical strength

Effects of fueling profiles on plasma transport

International Nuclear Information System (INIS)

Mense, A.T.; Houlberg, W.A.; Attenberger, S.E.; Milora, S.L.

1978-04-01

A one-dimensional (1-D), multifluid transport model is used to investigate the effects of particle fueling profiles on plasma transport in an ignition-sized tokamak (TNS). Normal diffusive properties of plasmas will likely maintain the density at the center of the discharge even if no active fueling is provided there. This significantly relaxes the requirements for fuel penetration. Not only is lower fuel penetration easier to achieve, but it may have the advantage of reducing or eliminating density gradient-driven trapped particle microinstabilities. Simulation of discrete pellet fueling indicates that relatively low velocity (approximately 10 3 m/sec) pellets may be sufficient to fuel a TNS-sized device (approximately 1.25-m minor radius), to produce a relatively broad, cool edge region of plasma which should reduce the potential for sputtering, and also to reduce the likelihood of trapped particle mode dominated transport. Low penetrating pellets containing up to 10 to 20 percent of the total plasma ions can produce fluctuations in density and temperature at the plasma edge, but the pressure profile and fusion alpha production remain almost constant

Effects of fuel particle size distributions on neutron transport in stochastic media

International Nuclear Information System (INIS)

Liang, Chao; Pavlou, Andrew T.; Ji, Wei

2014-01-01

Highlights: • Effects of fuel particle size distributions on neutron transport are evaluated. • Neutron channeling is identified as the fundamental reason for the effects. • The effects are noticeable at low packing and low optical thickness systems. • Unit cells of realistic reactor designs are studied for different size particles. • Fuel particle size distribution effects are not negligible in realistic designs. - Abstract: This paper presents a study of the fuel particle size distribution effects on neutron transport in three-dimensional stochastic media. Particle fuel is used in gas-cooled nuclear reactor designs and innovative light water reactor designs loaded with accident tolerant fuel. Due to the design requirements and fuel fabrication limits, the size of fuel particles may not be perfectly constant but instead follows a certain distribution. This brings a fundamental question to the radiation transport computation community: how does the fuel particle size distribution affect the neutron transport in particle fuel systems? To answer this question, size distribution effects and their physical interpretations are investigated by performing a series of neutron transport simulations at different fuel particle size distributions. An eigenvalue problem is simulated in a cylindrical container consisting of fissile fuel particles with five different size distributions: constant, uniform, power, exponential and Gaussian. A total of 15 parametric cases are constructed by altering the fissile particle volume packing fraction and its optical thickness, but keeping the mean chord length of the spherical fuel particle the same at different size distributions. The tallied effective multiplication factor (k eff ) and the spatial distribution of fission power density along axial and radial directions are compared between different size distributions. At low packing fraction and low optical thickness, the size distribution shows a noticeable effect on neutron

Effects of Fuel Type and Fuel Delivery System on Pollutant Emissions of Pride and Samand Vehicles

Directory of Open Access Journals (Sweden)

Akbar Sarhadi

2017-04-01

Full Text Available This research was aimed to study the effect of the type of fuel delivery system (petrol, dedicated or bifuel, the type of consumed fuel (petrol or gas, the portion of consumed fuel and also the duration of dual-fuelling in producing carbon monoxide, carbon dioxide and unburned hydrocarbons from Pride and Samand. According to research objectives, data gathering from 2000 vehicles has been done by visiting Hafiz Vehicle Inspection Center every day for 2 months. The results of this survey indicated that although there is no significant difference between various fuel delivery systems in terms of producing the carbon monoxide, carbon dioxide and unburned hydrocarbons by Samand, considering the emission amount of carbon dioxide, the engine performance of Pride in bifuel and dedicated state in GTXI and 132 types is more unsatisfactory than that of petrol state by 0.3 and 0.4%, respectively. On the other hand, consuming natural gas increases the amount of carbon monoxide emission in dual- fuel Pride by 0.18% and decreases that in dual-fuel Samand by 1.2%, which signifies the better design of Samand in terms of fuel pumps, used kit type and other engine parts to use this alternative fuel compared to Pride. Since the portion of consumed fuel and also duration of dual-fuelling does not have a significant effect on the amount of output pollutants from the studied vehicles, it can be claimed that the output substances from the vehicle exhaust are more related to the vehicle’s condition than the fuel type.

Emission Control Cost-Effectiveness of Alternative-Fuel Vehicles

OpenAIRE

Wang, Quanlu; Sperling, Daniel; Olmstead, Janis

1993-01-01

Although various legislation and regulations have been adopted to promote the use of alternative-fuel vehicles for curbing urban air pollution problems, there is a lack of systematic comparisons of emission control cost-effectiveness among various alternative-fuel vehicle types. In this paper, life-cycle emission reductions and life-cycle costs were estimated for passenger cars fueled with methanol, ethanol, liquified petroleum gas, compressed natural gas, and electricity. Vehicle emission es...

The Effect of Wood Fuels on Power Plant Availability

Energy Technology Data Exchange (ETDEWEB)

Orjala, Markku (Markku.Orjala@vtt.fi); Kaerki, Janne; Vainikka, Pasi [VTT Processes, Jyvaeskylae (Finland)

2003-11-01

There is a growing international interest in utilising renewable fuels, also in multifuel applications. Main reasons for this are the objective to reduce CO{sub 2} emissions and meet emission limits for NO{sub x} and SO{sub 2}. On one hand cofiring, defined as simultaneous combustion of different fuels in the same boiler, provides an alternative to achieve emission reductions. This is not only accomplished by replacing fossil fuel with biomass, but also as a result of the interaction of fuel reactants of different origin (e.g. biomass vs. coal). On the other hand, utilisation of solid biofuels and wastes sets new demands for process control and boiler design, as well as for combustion technologies, fuel blend control and fuel handling systems. In the case of wood-based fuels this is because of their high reactivity, high moisture content and combustion residues' high alkaline metal content. Combustion and cofiring properties of fuels have been studied both in VTT Processes' test facilities and in industrial-scale power plant boilers. The formation of alkaline and chlorine compounds in biomass combustion and their effect on boiler fouling and corrosion have been monitored by temperature controlled deposit formation and material monitoring probes. Deposit formation monitoring at full-scale boilers provides unique information on the rate of deposit formation, the effect of sootblowing and consequent changes in heat transfer. Additionally, the data from deposit formation monitoring has been shown to correlate with boiler performance, which gives basis for studying the interrelation of: fuel blend characteristics; deposit formation; boiler performance. If biomass fuels are blended with coal or peat, following implications may be expected: increased rate of deposit formation, shorter sootblowing interval, cleaning of heat transfer surfaces in revisions may be required, bed material agglomeration (in fluidised beds), increased risk of corrosion, higher in

Effect of aviation fuel type and fuel injection conditions on the spray characteristics of pressure swirl and hybrid air blast fuel injectors

Science.gov (United States)

Feddema, Rick

Feddema, Rick T. M.S.M.E., Purdue University, December 2013. Effect of Aviation Fuel Type and Fuel Injection Conditions on the Spray Characteristics of Pressure Swirl and Hybrid Air Blast Fuel Injectors. Major Professor: Dr. Paul E. Sojka, School of Mechanical Engineering Spray performance of pressure swirl and hybrid air blast fuel injectors are central to combustion stability, combustor heat management, and pollutant formation in aviation gas turbine engines. Next generation aviation gas turbine engines will optimize spray atomization characteristics of the fuel injector in order to achieve engine efficiency and emissions requirements. Fuel injector spray atomization performance is affected by the type of fuel injector, fuel liquid properties, fuel injection pressure, fuel injection temperature, and ambient pressure. Performance of pressure swirl atomizer and hybrid air blast nozzle type fuel injectors are compared in this study. Aviation jet fuels, JP-8, Jet A, JP-5, and JP-10 and their effect on fuel injector performance is investigated. Fuel injector set conditions involving fuel injector pressure, fuel temperature and ambient pressure are varied in order to compare each fuel type. One objective of this thesis is to contribute spray patternation measurements to the body of existing drop size data in the literature. Fuel droplet size tends to increase with decreasing fuel injection pressure, decreasing fuel injection temperature and increasing ambient injection pressure. The differences between fuel types at particular set conditions occur due to differences in liquid properties between fuels. Liquid viscosity and surface tension are identified to be fuel-specific properties that affect the drop size of the fuel. An open aspect of current research that this paper addresses is how much the type of aviation jet fuel affects spray atomization characteristics. Conventional aviation fuel specifications are becoming more important with new interest in alternative

Fuel fragmentation data review and separate effects testing

International Nuclear Information System (INIS)

Yueh, Ken. H.; Snis, N.; Mitchell, D.; Munoz-Reja, C.

2014-01-01

A simple alternative test has been developed to study the fuel fragmentation process at loss of coolant accident (LOCA) temperatures. The new test heats a short section of fuel, approximately two pellets worth of material, in a tube furnace open to air. An axial slit is cut in the test sample cladding to reduce radial restraint and to simulate ballooned condition. The tube furnace allows the fuel fragmentation process be observed during the experiment. The test was developed as a simple alternative so large number of tests could be conducted quickly and efficiently to identify key variables that influence fuel fragmentation and to zeroing on the fuel fragmentation burn-up threshold. Several tests were conducted, using fuel materials from fuel rods that were used in earlier integral tests to benchmark and validate the test technique. High burn-up fuel materials known to be above the fragmentation threshold was used to evaluate the fragmentation process as a function of temperature. Even with an axial slit and both ends open, no significant fuel detachment/release was detected until above 750°C. Additional tests were conducted with fuel materials at burn-ups closer to the fuel fragmentation burn-up threshold. Results from these tests indicate a minor power history effect on the fuel fragmentation burn-up threshold. An evaluation of available literature and data generated from this work suggest a fuel fragmentation burn-up threshold between 70 and 75 GWd/MTU. (author)

Effect of biodiesel fuels on diesel engine emissions

Energy Technology Data Exchange (ETDEWEB)

Lapuerta, Magin; Armas, Octavio; Rodriguez-Fernandez, Jose [Escuela Tecnica Superior de Ingenieros Industriales, University of Castilla-La Mancha, Avda. Camilo Jose Cela, s/n. 13071 Ciudad Real (Spain)

2008-04-15

The call for the use of biofuels which is being made by most governments following international energy policies is presently finding some resistance from car and components manufacturing companies, private users and local administrations. This opposition makes it more difficult to reach the targets of increased shares of use of biofuels in internal combustion engines. One of the reasons for this resistance is a certain lack of knowledge about the effect of biofuels on engine emissions. This paper collects and analyzes the body of work written mainly in scientific journals about diesel engine emissions when using biodiesel fuels as opposed to conventional diesel fuels. Since the basis for comparison is to maintain engine performance, the first section is dedicated to the effect of biodiesel fuel on engine power, fuel consumption and thermal efficiency. The highest consensus lies in an increase in fuel consumption in approximate proportion to the loss of heating value. In the subsequent sections, the engine emissions from biodiesel and diesel fuels are compared, paying special attention to the most concerning emissions: nitric oxides and particulate matter, the latter not only in mass and composition but also in size distributions. In this case the highest consensus was found in the sharp reduction in particulate emissions. (author)

Effects of salvage logging and pile-and-burn on fuel loading, potential fire behaviour, fuel consumption and emissions

Science.gov (United States)

Morris C. Johnson; Jessica E. Halofsky; David L. Peterson

2013-01-01

We used a combination of field measurements and simulation modelling to quantify the effects of salvage logging, and a combination of salvage logging and pile-and-burn fuel surface fuel treatment (treatment combination), on fuel loadings, fire behaviour, fuel consumption and pollutant emissions at three points in time: post-windstorm (before salvage logging), post-...

Air quality effects of alternative fuels. Final report

Energy Technology Data Exchange (ETDEWEB)

Guthrie, P.; Ligocki, M.; Looker, R.; Cohen, J.

1997-11-01

To support the Alternative Fuels Utilization Program, a comparison of potential air quality effects of alternative transportation fuels is being performed. This report presents the results of Phase 1 of this program, focusing on reformulated gasoline (RFG), methanol blended with 15 percent gasoline (M85), and compressed natural gas (CNG). The fuels are compared in terms of effects on simulated future concentrations of ozone and mobile source air toxics in a photochemical grid model. The fuel comparisons were carried out for the future year 2020 and assumed complete replacement of gasoline in the projected light-duty gasoline fleet by each of the candidate fuels. The model simulations were carried out for the areas surrounding Los Angeles and Baltimore/DC, and other (non-mobile) sources of atmospheric emissions were projected according to published estimates of economic and population growth, and planned emission control measures specific to each modeling domain. The future-year results are compared to a future-year run with all gasoline vehicle emissions removed. The results of the comparison indicate that the use of M85 is likely to produce similar ozone and air toxics levels as those projected from the use of RFG. Substitution of CNG is projected to produce significantly lower levels of ozone and the mobile source air toxics than those projected for RFG or M85. The relative benefits of CNG substitution are consistent in both modeling domains. The projection methodologies used for the comparison are subject to a large uncertainty, and modeled concentration distributions depend on meteorological conditions. The quantitative comparison of fuel effects is thus likely to be sensitive to alternative assumptions. The consistency of the results for two very different modeling domains, using very different base assumptions, lends credibility to the qualitative differentiation among these fuels. 32 refs., 42 figs., 47 tabs.

Water confinement effects on fuel assembly motion and damping

International Nuclear Information System (INIS)

Brenneman, B.; Shah, S.J.; Williams, G.T.; Strumpell, J.H.

2003-01-01

It has been established by other authors that the accelerations of the water confined by the reactor core baffle plates has a significant effect on the responses of all the fuel assemblies during LOCA or seismic transients. This particular effect is a consequence of the water being essentially incompressible, and thus experiencing the same horizontal accelerations as the imposed baffle plate motions. These horizontal accelerations of the fluid induce lateral pressure gradients that cause horizontal buoyancy forces on any submerged structures. These forces are in the same direction as the baffle accelerations and, for certain frequencies at least, tend to reduce the relative displacements between the fuel and baffle plates. But there is another confinement effect - the imposed baffle plate velocities must also be transmitted to the water. If the fuel assembly grid strips are treated as simple hydro-foils, these horizontal velocity components change the fluid angle of attack on each strip, and thus may induce large horizontal lift forces on each grid in the same direction as the baffle plate velocity. There is a similar horizontal lift due to inclined flow over the rods when axial flow is present. These combined forces appear to always reduce the relative displacements between the fuel and baffle plates for any significant axial flow velocity. Modeling this effect is very simple. It was shown in previous papers that the mechanism for the large fuel assembly damping due to axial flow may be the hydrodynamic forces on the grid strips, and that this is very well represented by discrete viscous dampers at each grid elevation. To include the imposed horizontal water velocity effects, on both the grids and rods, these dampers are simply attached to the baffle plate rather than 'ground'. The large flow-induced damping really acts in a relative reference frame rather than an absolute or inertial reference frame, and thus it becomes a flow-induced coupling between the fuel

A Study on Rack Thickness Effect for Spent Fuel Pool Storage

International Nuclear Information System (INIS)

Kim, Mi Jin; Lee, Hee-Jae; Sohn, Dong-Seong

2015-01-01

For the effective storage of used fuel, the development of high performance neutron absorbing materials is needed. One of the major concern for the used fuel storage is the assurance to keep subcriticality of the storage rack and the high performance neutron absorbing material is the vital part to assure this requirement. According to NRC guide line, the k-effective of the spent fuel storage racks must not exceed 0.95. To ensure its safety, subcriticality analysis is required. Subcriticality analysis of the used storage in spent fuel pool have been performed by different authors. Criticality calculations for light water reactor spent fuel storage rack were carried out by Jae et al. They used AMPX-KENO IV code and considered the effect of rack pitch and rack thickness for consolidated fuel. The criticality analysis has performed at Gd 0.2 and 1 wt% according to thickness change. As thickness increases, the volume of the spent fuel pool rack increases. Therefore, absorbing material also increases according to thickness

A Study on Rack Thickness Effect for Spent Fuel Pool Storage

Energy Technology Data Exchange (ETDEWEB)

Kim, Mi Jin; Lee, Hee-Jae; Sohn, Dong-Seong [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2015-05-15

For the effective storage of used fuel, the development of high performance neutron absorbing materials is needed. One of the major concern for the used fuel storage is the assurance to keep subcriticality of the storage rack and the high performance neutron absorbing material is the vital part to assure this requirement. According to NRC guide line, the k-effective of the spent fuel storage racks must not exceed 0.95. To ensure its safety, subcriticality analysis is required. Subcriticality analysis of the used storage in spent fuel pool have been performed by different authors. Criticality calculations for light water reactor spent fuel storage rack were carried out by Jae et al. They used AMPX-KENO IV code and considered the effect of rack pitch and rack thickness for consolidated fuel. The criticality analysis has performed at Gd 0.2 and 1 wt% according to thickness change. As thickness increases, the volume of the spent fuel pool rack increases. Therefore, absorbing material also increases according to thickness.

Radiation effects in fuel materials for fission reactors

International Nuclear Information System (INIS)

Matzke, H.

1983-01-01

Physical and chemical changes that occur in fuel materials during fission are described. Emphasis is placed on the fuels used today, or those foreseen for the future, hence oxides and carbides of uranium and plutonium. Examples are given to illustrate the most interesting neutron effects. (author)

Experimental study of fuel sootiness effects on flashover

Energy Technology Data Exchange (ETDEWEB)

Tsai, Kuang-Chung, E-mail: tsaikc@ccms.nkfust.edu.tw [Dept. of Safety, Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, 2 Juoyue Road, Nantzu, Kaohsiung 811, Taiwan (China); Chen, Hung-Hsiang [Dept. of Safety, Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, 2 Juoyue Road, Nantzu, Kaohsiung 811, Taiwan (China)

2010-06-15

Previous fire safety studies have demonstrated that flashover can result in severe injure and death and heat radiating back to a fuel is an important mechanism. Fuel sootiness dominates in radiative heat transfer. However, empirical correlations from previous investigations did not consider the fuel sootiness but nevertheless generated reasonably good predictions of flashover. In this study, a series of experiments was employed to examine fuel sootiness effects on flashover. The fuels used, in the order of their sootiness, were gasoline, n-hexane, iso-propanol and methanol. These fuels were filled in circular pans 100-320 mm in diameter to generate fires with different heat release rates and levels of sootiness. The pans were in 1/3 the size of the ISO 9705 test chamber. After ignition, the heat release rate (HRR), temperature inside the chamber, as well as heat flux on the floor and time to flashover (t{sub fo}) were determined. Experimental data show that HRR at flashover and t{sub fo} were strongly corrected and their relationship was independent of the fuel burned. Although heat feedback to the floor increased as fuel sootiness increased, consequently enhancing the burning of sooty fuels, flashover occurs only when the HRR at flashover criterion is reached.

FUEL CONSUMPTION EFFECT OF COMMERCIAL TURBOFANS ON GLOBAL WARMING

Energy Technology Data Exchange (ETDEWEB)

Onder Turan; T. Hikmet Karakoc [School of Civil Aviation, Anadolu University, Eskisehir (Turkey)

2008-09-30

The main objective pursued in this study is to parametrically investigate the fuel consumption effect of commercial turbofans on global warming. In this regard, Of the important parameters, specific fuel consumption of a commercial turbofans is taken into consideration. In order to minimize the effect of fuel consumption on global warming, the values of engine design parameters are optimized for maintaining minimum specific fuel consumption of high bypass turbofan engine under different flight conditions and design criteria. The backbones of optimization approach consisted of elitism-based genetic algorithm coupled with real parametric cycle analysis of a turbofan engine. For solving optimization problem a new software program is developed in MATLAB, while objective function is determined for minimizing the specific fuel consumption by considering the following parameters such as the fan pressure ratio ({pi}{sub f}), bypass ratio ({alpha}) and the fuel heating value [h{sub PR}-(kJ/kg)]. Accordingly, it may be concluded that the software program developed can successfully solve optimization problems at 1.2{le}{pi}{sub f}{le}2, 2{le}{alpha}{le}10 and 23000{le}h{sub PR}{le}120000 with aircraft flight Mach number {le}0.8. Fuel types used in preliminary engine cycle analysis were JP-4, JP-5, JP-8 and hydrogen in this paper.

Measuring method for effective neutron multiplication factor upon containing irradiated fuel assembly

International Nuclear Information System (INIS)

Ueda, Makoto; Mitsuhashi, Ishi; Sasaki, Tomoharu.

1993-01-01

A portion of irradiated fuel assemblies at a place where a reactivity effect is high, that is, at a place where neutron importance is high is replaced with standard fuel assemblies having a known composition to measure neutron fluxes at each of the places. An effective composition at the periphery of the standard fuel assemblies is determined by utilizing a calibration curve determined separately based on the composition and neutron flux values of the standard assemblies. By using the calibration curve determined separately based on this composition and the known composition of the standard fuel assemblies, an effective neutron multiplication factor for the fuel containing portion containing the irradiated fuel assemblies is recognized. Then, subcriticality is ensured and critical safety upon containing the fuel assemblies can be secured quantitatively. (N.H.)

Learning FuelPHP for effective PHP development

CERN Document Server

Tweedie, Ross

2013-01-01

The book follows a standard tutorial approach, which will enable readers to use the FuelPHP framework efficiently while developing PHP applications.If you are a PHP developer who is looking to learn more about using the FuelPHP framework for effective PHP development, this book is ideal for you. If you are interested in this book, you should already have a basic understanding of general PHP development.

Fundamental characterization of alternate fuel effects in continuous combustion systems

Energy Technology Data Exchange (ETDEWEB)

Blazowski, W.S.; Edelman, R.B.; Harsha, P.T.

1978-09-11

The overall objective of this contract is to assist in the development of fuel-flexible combustion systems for gas turbines as well as Rankine and Stirling cycle engines. The primary emphasis of the program is on liquid hydrocarbons produced from non-petroleum resouces. Fuel-flexible combustion systems will provide for more rapid transition of these alternate fuels into important future energy utilization centers (especially utility power generation with the combined cycle gas turbine). The specific technical objectives of the program are to develop an improved understanding of relationships between alternate fuel properties and continuous combustion system effects, and to provide analytical modeling/correlation capabilities to be used as design aids for development of fuel-tolerant combustion systems. Efforts this past year have been to evaluate experimental procedures for studying alternate fuel combustion effects and to determine current analytical capabilities for prediction of these effects. Jet Stirred Combustor studies during this period have produced new insights into soot formation in strongly backmixed systems and have provided much information for comparison with analytical predictions. The analytical effort included new applications of quasi-global modeling techniques as well as comparison of prediction with the experimental results generated.

Development of Dynamic Spent Nuclear Fuel Environmental Effect Analysis Model

International Nuclear Information System (INIS)

Jeong, Chang Joon; Ko, Won Il; Lee, Ho Hee; Cho, Dong Keun; Park, Chang Je

2010-07-01

The dynamic environmental effect evaluation model for spent nuclear fuel has been developed and incorporated into the system dynamic DANESS code. First, the spent nuclear fuel isotope decay model was modeled. Then, the environmental effects were modeled through short-term decay heat model, short-term radioactivity model, and long-term heat load model. By using the developed model, the Korean once-through nuclear fuel cycles was analyzed. The once-through fuel cycle analysis was modeled based on the Korean 'National Energy Basic Plan' up to 2030 and a postulated nuclear demand growth rate until 2150. From the once-through results, it is shown that the nuclear power demand would be ∼70 GWe and the total amount of the spent fuel accumulated by 2150 would be ∼168000 t. If the disposal starts from 2060, the short-term decay heat of Cs-137 and Sr-90 isotopes are W and 1.8x10 6 W in 2100. Also, the total long-term heat load in 2100 will be 4415 MW-y. From the calculation results, it was found that the developed model is very convenient and simple for evaluation of the environmental effect of the spent nuclear fuel

Effect of engine parameters and gaseous fuel type on the cyclic variability of dual fuel engines

Energy Technology Data Exchange (ETDEWEB)

Mohamed Y.E. Selim [United Arab Emirates University, Al-Ain (United Arab Emirates). Mechanical Engineering Department, Faculty of Engineering

2005-05-01

This paper presents an analysis of the cycle-to-cycle combustion variation as reflected in the combustion pressure data of a single cylinder, naturally aspirated, four stroke, Ricardo E6 engine converted to run as dual fuel engine on diesel and gaseous fuel of LPG or methane. A measuring set-up consisting of a piezo-electric pressure transducer with charge amplifier and fast data acquisition card installed on an IBM microcomputer was used to gather the data of up to 1200 consecutive combustion cycles of the cylinder under various combination of engine operating and design parameters. These parameters included type of gaseous fuel, engine load, compression ratio, pilot fuel injection timing, pilot fuel mass, and engine speed. The data for each operating conditions were analyzed for the maximum pressure, the maximum rate of pressure rise representing the combustion noise, and indicated mean effective pressure. The cycle-to-cycle variation is expressed as the mean value, standard deviation, and coefficient of variation of these three parameters. It was found that the type of gaseous fuel and engine operating and design parameters affected the combustion noise and its cyclic variation and these effects have been presented. 21 refs., 6 figs., 1 tab.

Fuel cell generator with fuel electrodes that control on-cell fuel reformation

Science.gov (United States)

Ruka, Roswell J [Pittsburgh, PA; Basel, Richard A [Pittsburgh, PA; Zhang, Gong [Murrysville, PA

2011-10-25

A fuel cell for a fuel cell generator including a housing including a gas flow path for receiving a fuel from a fuel source and directing the fuel across the fuel cell. The fuel cell includes an elongate member including opposing first and second ends and defining an interior cathode portion and an exterior anode portion. The interior cathode portion includes an electrode in contact with an oxidant flow path. The exterior anode portion includes an electrode in contact with the fuel in the gas flow path. The anode portion includes a catalyst material for effecting fuel reformation along the fuel cell between the opposing ends. A fuel reformation control layer is applied over the catalyst material for reducing a rate of fuel reformation on the fuel cell. The control layer effects a variable reformation rate along the length of the fuel cell.

Sanitary effects of fossil fuels

International Nuclear Information System (INIS)

Nifenecker, H.

2006-01-01

In this compilation are studied the sanitary effects of fossil fuels, behavioral and environmental sanitary risks. The risks in connection with the production, the transport and the distribution(casting) are also approached for the oil(petroleum), the gas and the coal. Accidents in the home are evoked. The risks due to the atmospheric pollution are seen through the components of the atmospheric pollution as well as the sanitary effects of this pollution. (N.C.)

Boiling transition phenomenon in BWR fuel assemblies effect of fuel spacer shape on critical power

International Nuclear Information System (INIS)

Yamamoto, Yasushi; Morooka, Shin-ichi; Mitsutake, Toru; Yokobori, Seiichi; Kimura, Jiro.

1996-01-01

A thorough understanding of the thermal-hydraulic phenomena near fuel spacer is necessary for the accurate prediction of the critical power of BWR fuel assemblies, and is thus essential for effective developments of a new BWR fuel assembly. The main purpose of this study is to develop an accurate method for predicting the effect of spacer shapes on critical power. Tests have been conducted under actual BWR operating conditions, using an annulus flow channel consisting of a heated rod and circular-tube channel, and BWR simulated 4x4 rod bundles with heater rods unheated just upsteam of spacer. The effect of spacer shapes on critical power was predicted analytically based on the droplet deposition rate estimation. The droplet deposition rate for different spacer shapes was calculated using a single-phase flow model. The prediction results were compared with the test results for the annulus flow channel using ring-type spacers. Analytical results of critical power agreed with measured critical power from point of the effects of changes in the rod-spacer clearance and the spacer thickness on critical power. (author)

Bayesian modelling of household solid fuel use: insights towards designing effective interventions to promote fuel switching in Africa.

Science.gov (United States)

Rehfuess, Eva A; Briggs, David J; Joffe, Mike; Best, Nicky

2010-10-01

Indoor air pollution from solid fuel use is a significant risk factor for acute lower respiratory infections among children in sub-Saharan Africa. Interventions that promote a switch to modern fuels hold a large health promise, but their effective design and implementation require an understanding of the web of upstream and proximal determinants of household fuel use. Using Demographic and Health Survey data for Benin, Kenya and Ethiopia together with Bayesian hierarchical and spatial modelling, this paper quantifies the impact of household-level factors on cooking fuel choice, assesses variation between communities and districts and discusses the likely nature of contextual effects. Household- and area-level characteristics appear to interact as determinants of cooking fuel choice. In all three countries, wealth and the educational attainment of women and men emerge as important; the nature of area-level factors varies between countries. In Benin, a two-level model with spatial community random effects best explains the data, pointing to an environmental explanation. In Ethiopia and Kenya, a three-level model with unstructured community and district random effects is selected, implying relatively autonomous economic and social areas. Area-level heterogeneity, indicated by large median odds ratios, appears to be responsible for a greater share of variation in the data than household-level factors. This may be an indication that fuel choice is to a considerable extent supply-driven rather than demand-driven. Consequently, interventions to promote fuel switching will carefully need to assess supply-side limitations and devise appropriate policy and programmatic approaches to overcome them. To our knowledge, this paper represents the first attempt to model the determinants of solid fuel use, highlighting socio-economic differences between households and, notably, the dramatic influence of contextual effects. It illustrates the potential that multilevel and spatial

Effective equivalencies of industrial fuels; Equivalencias efetivas de combustiveis industriais

Energy Technology Data Exchange (ETDEWEB)

Fehr, Manfred [Uberlandia Univ., MG (Brazil). Dept. de Engenharia Quimica

1986-01-01

This work perform comparison criteria between various solid, liquid and gaseous fuels, under several burn conditions. The objective of this comparison is to choose the most cost-effective fuel for heat generation, including the variables of fuel price, consumption, waste generation and safety conditions 16 refs., 1 fig., 8 tabs.

Design and analytic evaluation of a rim effect reduction type LWR fuel for extending burnup

International Nuclear Information System (INIS)

Matsumura, Tetsuo; Kameyama, Takanori; Kinoshita, Motoyasu

1991-01-01

We have designed a new concept fuel design 'Rim effect reduction type fuel' which has thin natural UO 2 layer on surface of a UO2 pellet. Our neutronic analyses with ANRB code show this fuel design can reduce rim effect (burnup at plelet rim) by about 30 GWd/t comparing a normal fuel. It is known that a high burnup fuel has different microstructure from as-fabricated one at fuel rim (which is called as rim region) due to rim effect. Therefore this fuel design can expect smaller rim region than a normal fuel. Our fuel performance analyses with EIMUS code show this fuel design can reduce fuel center temperature at high burnup if thermal conductivity of fuel pellet decreases with burnup in inverse proportion. However, this fuel design increases fuel center temperature at low and middle burnup than a normal fuel due to increase of thermal power density at pellet center. Additionally Irradiation experiment of this fuel design can be considered to offer important data which make clear the relation between rim effect and fuel performance. (author)

On the effects of fuel properties and injection timing in partially premixed compression ignition of low octane fuels

KAUST Repository

Naser, Nimal

2017-06-29

A better understanding on the effects of fuel properties and injection timing is required to improve the performance of advanced engines based on low temperature combustion concepts. In this work, an experimental and computational study was conducted to investigate the effects of physical and chemical kinetic properties of low octane fuels and their surrogates in partially premixed compression ignition (PPCI) engines. The main objective was to identify the relative importance of physical versus chemical kinetic properties in predicting practical fuel combustion behavior across a range of injection timings. Two fuel/surrogate pairs were chosen for comparison: light naphtha (LN) versus the primary reference fuel (PRF) with research octane number of 65 (PRF 65), and FACE (fuels for advanced combustion engines) I gasoline versus PRF 70. Two sets of parametric studies were conducted: the first varied the amount of injected fuel mass at different injection timings to match a fixed combustion phasing, and the second maintained the same injected fuel mass at each injection timing to assess resulting combustion phasing changes. Full-cycle computational fluid dynamic engine simulations were conducted by accounting for differences in the physical properties of the original and surrogate fuels, while employing identical chemical kinetics. The simulations were found to capture trends observed in the experiments, while providing details on spatial mixing and chemical reactivity for different fuels and injection timings. It was found that differences in physical properties become increasingly important as injection timing was progressively delayed from premixed conditions, and this was rationalized by analysis of mixture stratification patterns resulting from injection of fuels with different physical properties. The results suggest that accurate descriptions of both physical and chemical behavior of fuels are critical in predictive simulations of PPCI engines for a wide range of

On the effects of fuel properties and injection timing in partially premixed compression ignition of low octane fuels

KAUST Repository

Naser, Nimal; Jaasim, Mohammed; Atef, Nour; Chung, Suk-Ho; Im, Hong G.; Sarathy, Mani

2017-01-01

A better understanding on the effects of fuel properties and injection timing is required to improve the performance of advanced engines based on low temperature combustion concepts. In this work, an experimental and computational study was conducted to investigate the effects of physical and chemical kinetic properties of low octane fuels and their surrogates in partially premixed compression ignition (PPCI) engines. The main objective was to identify the relative importance of physical versus chemical kinetic properties in predicting practical fuel combustion behavior across a range of injection timings. Two fuel/surrogate pairs were chosen for comparison: light naphtha (LN) versus the primary reference fuel (PRF) with research octane number of 65 (PRF 65), and FACE (fuels for advanced combustion engines) I gasoline versus PRF 70. Two sets of parametric studies were conducted: the first varied the amount of injected fuel mass at different injection timings to match a fixed combustion phasing, and the second maintained the same injected fuel mass at each injection timing to assess resulting combustion phasing changes. Full-cycle computational fluid dynamic engine simulations were conducted by accounting for differences in the physical properties of the original and surrogate fuels, while employing identical chemical kinetics. The simulations were found to capture trends observed in the experiments, while providing details on spatial mixing and chemical reactivity for different fuels and injection timings. It was found that differences in physical properties become increasingly important as injection timing was progressively delayed from premixed conditions, and this was rationalized by analysis of mixture stratification patterns resulting from injection of fuels with different physical properties. The results suggest that accurate descriptions of both physical and chemical behavior of fuels are critical in predictive simulations of PPCI engines for a wide range of

First results on the effect of fuel-cladding eccentricity

International Nuclear Information System (INIS)

Panka, I.; Kereszturi, A.

2009-01-01

In the traditional fuel-behaviour or hot channel calculations it is assumed that the fuel pellet is centered within the clad. However, in the real life the pellet could be positioned asymmetrically within the clad, which leads to asymmetric gap conductance and therefore it is worthwhile to investigate the magnitude of the effect on maximal fuel temperature and surface heat flux. In this paper our first experiences are presented on this topic. (Authors)

Thermal-hydraulic effects of transition to improved System 80TM fuel

International Nuclear Information System (INIS)

Rodack, T.; Joffre, P.F.; Kapoor, R.K.

2004-01-01

ABB CE's improved System 80 TM PWR fuel design includes GUARDIAN debris-resistant features and laser-welded Zircaloy grids. The GUARDIAN features include an Inconel grid with debris-filtering features located just above the Lower End Fitting, and a solid fuel rod bottom end cap that extends above the filtering features. Tests and analyses were done to establish the impact of these design improvements on fuel assembly hydraulic performance. Further analysis was done to determine the mixed core thermal-hydraulic performance as the transition is made over two fuel cycles to a full core of the improved System 80 TM fuel. Results confirm that the Thermal-Hydraulic (T-H) effects of the reduction in hydraulic resistance between the improved and resident fuel due to the laser-welded Zircaloy grids offsets the effects of the increased resistance GUARDIAN grid. Therefore, the mechanically improved System 80 TM fuel can be implemented with no net impact on Departure from Nucleate Boiling (DNB) margin in transition cores. (author)

Effect of Biodiesel Fuel Injection Timing and Venture for Gaseous Fuel Induction on the Performance, Emissions and Combustion Characteristics of Dual Fuel Engine

Directory of Open Access Journals (Sweden)

Mallikarjun Bhovi

2018-02-01

Full Text Available Advancing or retarding pilot fuel injection timing in a diesel engine provided with either conventional mechanical fuel injection (CMFIS or high pressure injection as in common rail fuel injection (CRDI systems can significantly affect its performance and tail pipe emissions. Performance of diesel engine when fueled with various biofuels as well as gaseous fuels tends to vary with subsequent changes in pilot fuel injection timings. Biodiesel derived from rubber seed oil called Rubber Seed Oil Methyl Ester (RuOME and hydrogen (H2 and hydrogen enriched compressed natural gas called (HCNG both being renewable fuels when used in diesel engines modified to operate in dual fuel mode can provide complete replacement for fossil diesel. In the present study, effect of injection timings and venture design for gas mixing on the performance, combustion and emission characteristics of dual fuel engine fitted with both CMFIS and CRDI injection systems and operated on RuOME and HCNG/hydrogen has been investigated. Results showed that high pressure CRDI assisted injection of RuOME with optimized mixing chamber (carburetor for hydrogen induction in dual fuel engine performed improved compared to that with CMFIS. In addition, for the same fuel combinations, CRDI resulted in lower biodiesel consumption, lower carbon monoxide (BSCO and hydrocarbon (BSHC emissions and increased NOx emissions than CMFIS operation.

Modeling fuels and fire effects in 3D: Model description and applications

Science.gov (United States)

Francois Pimont; Russell Parsons; Eric Rigolot; Francois de Coligny; Jean-Luc Dupuy; Philippe Dreyfus; Rodman R. Linn

2016-01-01

Scientists and managers critically need ways to assess how fuel treatments alter fire behavior, yet few tools currently exist for this purpose.We present a spatially-explicit-fuel-modeling system, FuelManager, which models fuels, vegetation growth, fire behavior (using a physics-based model, FIRETEC), and fire effects. FuelManager's flexible approach facilitates...

Effect of reduced enrichment on the fuel cycle for research reactors

International Nuclear Information System (INIS)

Travelli, A.

1982-01-01

The new fuels developed by the RERTR Program and by other international programs for application in research reactors with reduced uranium enrichment (<20% EU) are discussed. It is shown that these fuels, combined with proper fuel-element design and fuel-management strategies, can provide at least the same core residence time as high-enrichment fuels in current use, and can frequently significantly extend it. The effect of enrichment reduction on other components of the research reactor fuel cycle, such as uranium and enrichment requirements, fuel fabrication, fuel shipment, and reprocessing are also briefly discussed with their economic implications. From a systematic comparison of HEU and LEU cores for the same reference research reactor, it is concluded that the new fuels have a potential for reducing the research reactor fuel cycle costs while reducing, at the same time, the uranium enrichment of the fuel

Effects of degree of approval and message on utility of nuclear fuel cycle

International Nuclear Information System (INIS)

Tanigaki, Toshihiko

2007-01-01

It is said that the effectiveness of nuclear power generation is the greatest factor contributing to whether or not people support the nuclear power policy. The major objectives of this research are twofold: from among opinions regarding the effectiveness of the nuclear fuel cycle, to clarify what kinds of opinions people support and what kinds of opinions have influenced judgments about the pros and cons of the nuclear fuel cycle; and to measure the extent to which people's awareness of the nuclear fuel cycle is influenced by numerical information that has been added to a nuclear-fuel-cycle-related message that has been created on the basis of results of the survey conducted for the first objective mentioned above. As for the first objective, the survey results revealed that the opinion 'the establishment of a nuclear fuel cycle leads to the effective use of energy resources' did not garner much support from the public. However, it was indicated that people being for or against that opinion may have relatively great effect on their judgment regarding the pros and ons of nuclear fuel cycle establishment. For the second objective, we showed people the messages the nuclear fuel cycle enables effective use of natural uranium' and 'the nuclear fuel cycle enables tens times more effective use of natural uranium' to the latter of which numerical information was added. As a result, we found no difference in people's attitude toward the nuclear fuel cycle even if numerical information was added to a nuclear-fuel-cycle-related message. (author)

Reactivity effect of spent fuel depending on burn-up history

International Nuclear Information System (INIS)

Hayashi, Takafumi; Suyama, Kenya; Nomura, Yasushi

2001-06-01

It is well known that a composition of spent fuel depends on various parameter changes throughout a burn-up period. In this study we aimed at the boron concentration and its change, the coolant temperature and its spatial distribution, the specific power, the operation mode, and the duration of inspection, because the effects due to these parameters have not been analyzed in detail. The composition changes of spent fuel were calculated by using the burn-up code SWAT, when the parameters mentioned above varied in the range of actual variations. Moreover, to estimate the reactivity effect caused by the composition changes, the criticality calculations for an infinite array of spent fuel were carried out with computer codes SRAC95 or MVP. In this report the reactivity effects were arranged from the viewpoint of what parameters gave more positive reactivity effect. The results obtained through this study are useful to choose the burn-up calculation model when we take account of the burn-up credit in the spent fuel management. (author)

Effect of Alternative Fuels on SCR Chemistry

OpenAIRE

Faramarzi, Simin

2012-01-01

In the time line of world industrial age, the most important era begins in the late 18th century when the use of fossil fuels was growing intensively. This approach has continued and developed up to the 20th century. Besides, this trend has had side effects like polluting environment. Air pollution is one of the critical issues nowadays that stems from using hydrocarbon fuels. One type of the problematic compounds in polluting air is nitrogen oxides that can be produced in combustion process ...

Effects of spent nuclear fuel aging on disposal requirements

International Nuclear Information System (INIS)

McKee, R.W.; Johnson, K.I.; Huber, H.D.; Bierschbach, M.C.

1991-10-01

This paper describes results of a study to analyze the waste management systems effects of extended spent fuel aging on spent fuel disposal requirements. The analysis considers additional spent fuel aging up to a maximum of 50 years relative to the currently planned 2010 repository startup in the United States. As part of the analysis, an equal energy disposition (EED) methodology was developed for determining allowable waste emplacement densities and waste container loading in a geologic repository. Results of this analysis indicate that substantial benefits of spent fuel aging will already have been achieved by a repository startup in 2010 (spent fuel average age will be 28 years). Even so, further significant aging benefits, in terms of reduced emplacement areas and mining requirements and reduced number of waste containers, will continue to accrue for at least another 50 years when the average spent fuel age would be 78 years, if the repository startup is further delayed

Burnup effect on nuclear fuel cycle cost using an equilibrium model

International Nuclear Information System (INIS)

Youn, S. R.; Kim, S. K.; Ko, W. I.

2014-01-01

The degree of fuel burnup is an important technical parameter to the nuclear fuel cycle, being sensitive and progressive to reduce the total volume of process flow materials and eventually cut the nuclear fuel cycle costs. This paper performed the sensitivity analysis of the total nuclear fuel cycle costs to changes in the technical parameter by varying the degree of burnups in each of the three nuclear fuel cycles using an equilibrium model. Important as burnup does, burnup effect was used among the cost drivers of fuel cycle, as the technical parameter. The fuel cycle options analyzed in this paper are three different fuel cycle options as follows: PWR-Once Through Cycle(PWR-OT), PWR-MOX Recycle, Pyro-SFR Recycle. These fuel cycles are most likely to be adopted in the foreseeable future. As a result of the sensitivity analysis on burnup effect of each three different nuclear fuel cycle costs, PWR-MOX turned out to be the most influenced by burnup changes. Next to PWR-MOX cycle, in the order of Pyro-SFR and PWR-OT cycle turned out to be influenced by the degree of burnup. In conclusion, the degree of burnup in the three nuclear fuel cycles can act as the controlling driver of nuclear fuel cycle costs due to a reduction in the volume of spent fuel leading better availability and capacity factors. However, the equilibrium model used in this paper has a limit that time-dependent material flow and cost calculation is impossible. Hence, comparative analysis of the results calculated by dynamic model hereafter and the calculation results using an equilibrium model should be proceed. Moving forward to the foreseeable future with increasing burnups, further studies regarding alternative material of high corrosion resistance fuel cladding for the overall

Effect of increased fuel temperature on emissions of oxides of nitrogen from a gas turbine combustor burning ASTM jet-A fuel

Science.gov (United States)

Marchionna, N. R.

1974-01-01

An annular gas turbine combustor was tested with heated ASTM Jet-A fuel to determine the effect of increased fuel temperature on the formation of oxides of nitrogen. Fuel temperature ranged from ambient to 700 K. The NOx emission index increased at a rate of 6 percent per 100 K increase in fuel temperature.

Effect of compressive force on PEM fuel cell performance

Science.gov (United States)

MacDonald, Colin Stephen

Polymer electrolyte membrane (PEM) fuel cells possess the potential, as a zero-emission power source, to replace the internal combustion engine as the primary option for transportation applications. Though there are a number of obstacles to vast PEM fuel cell commercialization, such as high cost and limited durability, there has been significant progress in the field to achieve this goal. Experimental testing and analysis of fuel cell performance has been an important tool in this advancement. Experimental studies of the PEM fuel cell not only identify unfiltered performance response to manipulation of variables, but also aid in the advancement of fuel cell modelling, by allowing for validation of computational schemes. Compressive force used to contain a fuel cell assembly can play a significant role in how effectively the cell functions, the most obvious example being to ensure proper sealing within the cell. Compression can have a considerable impact on cell performance beyond the sealing aspects. The force can manipulate the ability to deliver reactants and the electrochemical functions of the cell, by altering the layers in the cell susceptible to this force. For these reasons an experimental study was undertaken, presented in this thesis, with specific focus placed on cell compression; in order to study its effect on reactant flow fields and performance response. The goal of the thesis was to develop a consistent and accurate general test procedure for the experimental analysis of a PEM fuel cell in order to analyse the effects of compression on performance. The factors potentially affecting cell performance, which were a function of compression, were identified as: (1) Sealing and surface contact; (2) Pressure drop across the flow channel; (3) Porosity of the GDL. Each factor was analysed independently in order to determine the individual contribution to changes in performance. An optimal degree of compression was identified for the cell configuration in

Final Report - Effects of Impurities on Fuel Cell Performance and Durability

Energy Technology Data Exchange (ETDEWEB)

Trent Molter

2012-08-18

This program is focused on the experimental determination of the effects of key hydrogen side impurities on the performance of PEM fuel cells. Experimental data has been leveraged to create mathematical models that predict the performance of PEM fuel cells that are exposed to specific impurity streams. These models are validated through laboratory experimentation and utilized to develop novel technologies for mitigating the effects of contamination on fuel cell performance. Results are publicly disseminated through papers, conference presentations, and other means.

Effect of advanced fuel cycles on waste management policies

International Nuclear Information System (INIS)

Cavedon, J.M.; Haapalehto, T.

2005-01-01

The study aims at analysing a range of future fuel cycle options from the perspective of their impact on waste repository demand and specification. The study would focus on: Assessment of the characteristics of radioactive wastes arising from advanced nuclear fuel cycle options, repository performance analysis studies using source terms for waste arising from such advanced nuclear fuel cycles, identification of new options for waste management and disposal. Three families of fuel cycles having increasing recycling capabilities are assessed. Each cycle is composed of waste generating and management processes. Examples of waste generating processes are fuel factories (7 types) and reprocessing plants (7 types). Packaging and conditioning plants (7) and disposal facilities are examples of waste management processes. The characteristic of all these processes have been described and then total waste flows are summarised. In order to simplify the situation, three waste categories have been defined based on the IAEA definitions in order to emphasize the major effects of different types of waste. These categories are: short-life waste for surface or sub-surface disposal, long-life low heat producing waste for geological disposal, high-level waste for geological disposal. The feasibilities of the fuel cycles are compared in terms of economics, primary resource consumption and amount of waste generated. The effect of high-level waste composition for the repository performance is one of the tools in these comparisons. The results of this will be published as an NEA publication before the end of 2005. (authors)

An Analysis of Fuel Region to Region Dancoff Factor with the Random Mixture Effects of Moderator and Fuel Pebbles

International Nuclear Information System (INIS)

Kim, Song Hyun; Kim, Hong Chul; Kim, Jong Kyung; Noh, Jae Man

2009-01-01

Dancoff factor is an entering probability of the neutron escaped from specific fuel kernel to another one without the interaction with moderators. In order to analytically evaluate Dancoff factor considering double-heterogeneous effect, inter-pebble and intra-pebble Dancoff factors should be calculated, respectively. Intra-pebble Dancoff factor related with the fuel kernels in one pebble was analyzed in the past study. The fuel and moderator pebbles are randomly located in the pebble-type reactor. For the evaluation of inter-pebble Dancoff factor, a repetition of simple pebble structure is commonly assumed to simulate the complex geometry of pebble-type reactor. The evaluation using these structures can be underestimated because of the shadowing effects generated from the repetition of simple pebble structure. Fuel region to region Dancoff factor (FRDF) was defined as an entering probability of the neutron escaped from a specific fuel region to another one without any collision with moderator for a preliminary evaluation of inter-pebble Dancoff factor. To solve the underestimation problem of FRDF from the shadow effect, the specific pebble was assumed and FRDF was evaluated with the approximation method proposed in this study

the effect of advanced fuel designs on fuel utilization

International Nuclear Information System (INIS)

Sarikaya, B.; Colak, U.; Tombakoglu, M.; Yilmazbayhan, A.

1997-01-01

Fuel management is one of the key topic in nuclear engineering. It is possible to increase fuel burnup and reactor lifetime by using advanced fuel management strategies. In order to increase the cycle lifetime, required amount of excess reactivity must be added to system. Burnable poisons can be used to compensate this excess reactivity. Usually gadolinium (Gd) is used as burnable poison. But the use of Gd presents some difficulties that have not been encountered with the use of boron

Tri-fuel (diesel-biodiesel-ethanol) emulsion characterization, stability and the corrosion effect

Science.gov (United States)

Low, M. H.; Mukhtar, N. A. M.; Yohaness Hagos, Ftwi; Noor, M. M.

2017-10-01

This paper presents the result of experimenting emulsified tri-fuel in term of stability, physico-chemical properties and corrosion effect on three common metals. The results were interpreted in terms of the impact of five minutes emulsification approach. Tri-fuel emulsions were varied in proportion ratio consist of biodiesel; 0%, 5%, 10%, and ethanol; 5%, 10%, 15%. Fuel characterization includes density, calorific value, flash point, and kinematic viscosity. Flash point of tri-fuel emulsion came with range catalog. Calorific value of tri-fuel emulsion appeared in declining pattern as more ethanol and biodiesel were added. Biodiesel promoted flow resistance while ethanol with opposite effect. 15% ethanol content in tri-fuel emulsion separated faster than 10% ethanol content but ethanol content with 5% yield no phase separation at all. Close cap under static immersion with various ratio of tri-fuel emulsions for over a month, corrosiveness attack was detected via weight loss technique on aluminum, stainless steel and mild steel.

FUEL FORMULATION EFFECTS ON DIESEL FUEL INJECTION, COMBUSTION, EMISSIONS AND EMISSION CONTROL

Energy Technology Data Exchange (ETDEWEB)

Boehman, A; Alam, M; Song, J; Acharya, R; Szybist, J; Zello, V; Miller, K

2003-08-24

This paper describes work under a U.S. DOE sponsored Ultra Clean Fuels project entitled ''Ultra Clean Fuels from Natural Gas,'' Cooperative Agreement No. DE-FC26-01NT41098. In this study we have examined the incremental benefits of moving from low sulfur diesel fuel and ultra low sulfur diesel fuel to an ultra clean fuel, Fischer-Tropsch diesel fuel produced from natural gas. Blending with biodiesel, B100, was also considered. The impact of fuel formulation on fuel injection timing, bulk modulus of compressibility, in-cylinder combustion processes, gaseous and particulate emissions, DPF regeneration temperature and urea-SCR NOx control has been examined. The primary test engine is a 5.9L Cummins ISB, which has been instrumented for in-cylinder combustion analysis and in-cylinder visualization with an engine videoscope. A single-cylinder engine has also been used to examine in detail the impacts of fuel formulation on injection timing in a pump-line-nozzle fueling system, to assist in the interpretation of results from the ISB engine.

Fuel Effects on Emissions From Non-Road Engines

Energy Technology Data Exchange (ETDEWEB)

Murtonen, T.; Nylund, N.

2003-10-15

The objective of this project was to study how fuel quality affects the exhaust emissions from different kinds of non-road engines. The project was divided into two parts: emissions from small gasoline engines and emissions from diesel engines. The measured small engines were a 2-stroke chainsaw engine, and a 4-stroke OHV engine, which could be used in different applications. Measurements were done with three different fuels, with and without catalyst. Also a comparison between biodegradable vs. conventional lubrication oil was done with the 2-stroke engine. Measurements were done according to ISO8178 standard. The results clearly demonstrate that using a good quality fuel (e.g. low sulphur, low aromatics) and a catalyst gives the best outcome in overall emission levels from these small engines. In the second part two different diesel engines were tested with five different fuels. Two of the fuels were biodiesel blends. The engines were chosen to represent old and new engine technology. The old engine (MY 1985) was produced before EU emission regulations were in place, and the new engine fulfilled the current EU Stage 2 emission limits. These measurements were also done according to the ISO8178 standard. With the new engine comparison with and without oxidation catalyst was done using two fuels. The results in general are similar compared to the results from the small gasoline engines: fuel quality has an effect on the emissions and when combining a good quality fuel (e.g. low sulphur, low aromatics) and an oxidation catalyst the emission levels are significantly reduced. Also some unregulated emission measurements were done but those results are not included to this report.

Thermal Effects by Firing Oil Shale Fuel in CFB Boilers

Science.gov (United States)

Neshumayev, D.; Ots, A.; Parve, T.; Pihu, T.; Plamus, K.; Prikk, A.

It is well known that during firing of oil shale fuel the amount of heat released during its combustion per kg of fuel is significantly affected by the endothermic and exothermic processes taking place in mineral matter. These thermal effects are calcite and dolomite decomposing, marcasite FeS2 oxidising, CaO sulphation and formation of the new minerals. The given paper deals with the experimental study of the influence of these thermal effects of oil shale fuel having different heating value on total amount of heat released during combustion in calorimetric bomb, circulating fluidized bed (CFB) and pulverized-firing boiler (PFB). The large-scale (250 MWth) experiments were performed in the K11-1 CFB boiler of the Balti Power Plant. During experiments low heating value of a fuel varied within the range 8.5-11 MJ/kg. At the end some conclusions were drawn.

Effect of engine parameters and type of gaseous fuel on the performance of dual-fuel gas diesel engines. A critical review

Energy Technology Data Exchange (ETDEWEB)

Sahoo, B.B. [Centre for Energy, Indian Institute of Technology, Guwahati 781039 (India); Sahoo, N.; Saha, U.K. [Department of Mechanical Engineering, Indian Institute of Technology, Guwahati 781039 (India)

2009-08-15

Petroleum resources are finite and, therefore, search for their alternative non-petroleum fuels for internal combustion engines is continuing all over the world. Moreover gases emitted by petroleum fuel driven vehicles have an adverse effect on the environment and human health. There is universal acceptance of the need to reduce such emissions. Towards this, scientists have proposed various solutions for diesel engines, one of which is the use of gaseous fuels as a supplement for liquid diesel fuel. These engines, which use conventional diesel fuel and gaseous fuel, are referred to as 'dual-fuel engines'. Natural gas and bio-derived gas appear more attractive alternative fuels for dual-fuel engines in view of their friendly environmental nature. In the gas-fumigated dual-fuel engine, the primary fuel is mixed outside the cylinder before it is inducted into the cylinder. A pilot quantity of liquid fuel is injected towards the end of the compression stroke to initiate combustion. When considering a gaseous fuel for use in existing diesel engines, a number of issues which include, the effects of engine operating and design parameters, and type of gaseous fuel, on the performance of the dual-fuel engines, are important. This paper reviews the research on above issues carried out by various scientists in different diesel engines. This paper touches upon performance, combustion and emission characteristics of dual-fuel engines which use natural gas, biogas, producer gas, methane, liquefied petroleum gas, propane, etc. as gaseous fuel. It reveals that 'dual-fuel concept' is a promising technique for controlling both NO{sub x} and soot emissions even on existing diesel engine. But, HC, CO emissions and 'bsfc' are higher for part load gas diesel engine operations. Thermal efficiency of dual-fuel engines improve either with increased engine speed, or with advanced injection timings, or with increased amount of pilot fuel. The ignition

Fuel-steel mixing and radial mesh effects in power excursion simulations

International Nuclear Information System (INIS)

Chen, X.-N.; Rineiski, A.; Gabrielli, F.; Andriolo, L.; Vezzoni, B.; Li, R.; Maschek, W.; Kiefhaber, E.

2016-01-01

Highlights: • Fuel-steel mixing and radial mesh effects are significant on power excursion. • The earliest power peak is reduced and retarded by these two effects. • Unprotected loss of coolant transients in ESFR core are calculated. - Abstract: This paper deals with SIMMER-III once-through simulations of the earliest power excursion initiated by an unprotected loss of flow (ULOF) in the Working Horse design of the European Sodium Cooled Fast Reactor (ESFR). Since the sodium void effect is strictly positive in this core and dominant in the transient, a power excursion is initiated by sodium boiling in the ULOF case. Two major effects, namely (1) reactivity effects due to fuel-steel mixing after melting and (2) the radial mesh size, which were not considered originally in SIMMER simulations for ESFR, are studied. The first effect concerns the reactivity difference between the heterogeneous fuel/clad/wrapper configuration and the homogeneous mixture of steel and fuel. The full core homogenization (due to melting) effect is −2 $, though a smaller effect takes place in case of partial core melting. The second effect is due to the SIMMER sub-assembly (SA) coarse mesh treatment, where a simultaneous sodium boiling onset in all SAs belonging to one ring leads to an overestimated reactivity ramp. For investigating the influence of fuel/steel mixing effects, a lumped “homogenization” reactivity feedback has been introduced, being proportional to the molten steel mass. For improving the coarse mesh treatment, we employ finer radial meshes to take the subchannel effects into account, where the side and interior channels have different coolant velocities and temperatures. The simulation results show that these two effects have significant impacts on the earliest power excursion after the sodium boiling.

The effect of fuel chemistry on UO{sub 2} dissolution

Energy Technology Data Exchange (ETDEWEB)

Casella, Amanda, E-mail: amanda.casella@pnnl.gov [Pacific Northwest National Laboratory, PO Box 999, MSIN P7-25, Richland, WA 99352 (United States); Hanson, Brady, E-mail: brady.hanson@pnnl.gov [Pacific Northwest National Laboratory, PO Box 999, MSIN P7-27, Richland, WA 99352 (United States); Miller, William [University of Missouri Research Reactor, 1513 Research Park Drive, Columbia, MO 65211 (United States)

2016-08-01

The dissolution rate of both unirradiated UO{sub 2} and used nuclear fuel has been studied by numerous countries as part of the performance assessment of proposed geologic repositories. In the scenario of waste package failure and groundwater contact with the fuel, the effects of variables such as temperature, dissolved oxygen, and water and fuel chemistry on the dissolution rates of the fuel are necessary to provide a quantitative estimate of the potential release over geologic time frames. The primary objective of this research was to determine the influence these parameters, with primary focus on the fuel chemistry, have on the dissolution rate of unirradiated UO{sub 2} under oxidizing repository conditions and compare them to the rates predicted by current dissolution models. Both unirradiated UO{sub 2} and UO{sub 2} doped with varying concentrations of Gd{sub 2}O{sub 3}, to simulate used fuel composition after long time periods when radiolysis has minor contributions to dissolution, were examined. In general, a rise in temperature increased the dissolution rate of UO{sub 2} and had a larger effect on pure UO{sub 2} than on those doped with Gd{sub 2}O{sub 3}. Oxygen dependence was observed in the UO{sub 2} samples with no dopant and increased as the temperature rose; in the doped fuels less dependence was observed. The addition of gadolinia into the UO{sub 2} matrix resulted in a significant decrease in the dissolution rate. The matrix stabilization effect resulting from the dopant proved even more beneficial in lowering the dissolution rate at higher temperatures and dissolved O{sub 2} concentrations in the leachate where the rates would typically be elevated. - Highlights: • UO{sub 2} dissolution rates were measured for a matrix of repository relevant conditions. • Dopants in the UO{sub 2} matrix lowered the dissolution rate. • Reduction in rates by dopants were increased at elevated temperature and O{sub 2} levels. • UO{sub 2} may be overly

Analysis of impurity effect on Silicide fuels of the RSG-GAS core

International Nuclear Information System (INIS)

Tukiran-Surbakti

2003-01-01

Simulation of impurity effect on silicide fuel of the RSG-GAS core has been done. The aim of this research is to know impurity effect of the U-234 and U-236 isotopes in the silicide fuels on the core criticality. The silicide fuels of 250 g U loading and 19.75 of enrichment is used in this simulation. Cross section constant of fuels and non-structure material of core are generated by WIMSD/4 computer code, meanwhile impurity concentration was arranged from 0.01% to 2%. From the result of analysis can be concluded that the isotopes impurity in the fuels could make trouble in the core and the core can not be operated at critical after a half of its cycle length (350 MW D)

Effect of Intake Air Filter Condition on Vehicle Fuel Economy

Energy Technology Data Exchange (ETDEWEB)

Norman, Kevin M [ORNL; Huff, Shean P [ORNL; West, Brian H [ORNL

2009-02-01

The U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy and the U.S. Environmental Protection Agency (EPA) jointly maintain a fuel economy website (www.fueleconomy.gov), which helps fulfill their responsibility under the Energy Policy Act of 1992 to provide accurate fuel economy information [in miles per gallon (mpg)] to consumers. The site provides information on EPA fuel economy ratings for passenger cars and light trucks from 1985 to the present and other relevant information related to energy use such as alternative fuels and driving and vehicle maintenance tips. In recent years, fluctuations in the price of crude oil and corresponding fluctuations in the price of gasoline and diesel fuels have renewed interest in vehicle fuel economy in the United States. (User sessions on the fuel economy website exceeded 20 million in 2008 compared to less than 5 million in 2004 and less than 1 million in 2001.) As a result of this renewed interest and the age of some of the references cited in the tips section of the website, DOE authorized the Oak Ridge National Laboratory (ORNL) Fuels, Engines, and Emissions Research Center (FEERC) to initiate studies to validate and improve these tips. This report documents a study aimed specifically at the effect of engine air filter condition on fuel economy. The goal of this study was to explore the effects of a clogged air filter on the fuel economy of vehicles operating over prescribed test cycles. Three newer vehicles (a 2007 Buick Lucerne, a 2006 Dodge Charger, and a 2003 Toyota Camry) and an older carbureted vehicle were tested. Results show that clogging the air filter has no significant effect on the fuel economy of the newer vehicles (all fuel injected with closed-loop control and one equipped with MDS). The engine control systems were able to maintain the desired AFR regardless of intake restrictions, and therefore fuel consumption was not increased. The carbureted engine did show a decrease in

Responding effectively to fuel spills at airports

International Nuclear Information System (INIS)

Williams, L.E.

1991-01-01

Fuel spills are among the most frequent causes of emergency calls faced by airport firefighters. Most fuel spills are a result of human error and careless procedures. They always constitute an emergency and require fast, efficient action to prevent disaster. A fuel spill is an accidental release of fuel, in this case, from an aircraft fuel system, refueling vehicle or refueling system. A normal release of a few drops of fuel associated with a disconnection or other regular fueling operations should not be classified as a fuel spill. However, anytime fuel must be cleaned up and removed from an area, a fuel spill has occurred. Volatile fuels pose significant threats to people, equipment, facilities and cargo when they are released. Anyone near a spill, including ramp workers, fueling personnel and aircraft occupants, are in danger if the fuel ignites. Buildings and equipment in a spill area, such as terminals, hangars, aircraft, fuel trucks and service equipment also are at risk. An often neglected point is that aircraft cargo also is threatened by fuel spills

Effect of fuel injection pressure and injection timing of Karanja biodiesel blends on fuel spray, engine performance, emissions and combustion characteristics

International Nuclear Information System (INIS)

Agarwal, Avinash Kumar; Dhar, Atul; Gupta, Jai Gopal; Kim, Woong Il; Choi, Kibong; Lee, Chang Sik; Park, Sungwook

2015-01-01

Highlights: • Effect of FIP on microscopic spray characteristics. • Effect of FIP and SOI timing on CRDI engine performance, emissions and combustion. • Fuel injection duration shortened, peak injection rate increased with increasing FIP. • SMD (D 32 ) and AMD (D 10 ) of fuel droplets decreased for lower biodiesel blends. • Increase in biodiesel blend ratio and FIP, fuel injection duration decreased. - Abstract: In this investigation, effect of 10%, 20% and 50% Karanja biodiesel blends on injection rate, atomization, engine performance, emissions and combustion characteristics of common rail direct injection (CRDI) type fuel injection system were evaluated in a single cylinder research engine at 300, 500, 750 and 1000 bar fuel injection pressures at different start of injection timings and constant engine speed of 1500 rpm. The duration of fuel injection slightly decreased with increasing blend ratio of biodiesel (Karanja Oil Methyl Ester: KOME) and significantly decreased with increasing fuel injection pressure. The injection rate profile and Sauter mean diameter (D 32 ) of the fuel droplets are influenced by the injection pressure. Increasing fuel injection pressure generally improves the thermal efficiency of the test fuels. Sauter mean diameter (D 32 ) and arithmetic mean diameter (D 10 ) decreased with decreasing Karanja biodiesel content in the blend and significantly increased for higher blends due to relatively higher fuel density and viscosity. Maximum thermal efficiency was observed at the same injection timing for biodiesel blends and mineral diesel. Lower Karanja biodiesel blends (up to 20%) showed lower brake specific hydrocarbon (BSHC) and carbon monoxide (BSCO) emissions in comparison to mineral diesel. For lower Karanja biodiesel blends, combustion duration was shorter than mineral diesel however at higher fuel injection pressures, combustion duration of 50% blend was longer than mineral diesel. Up to 10% Karanja biodiesel blends in a CRDI

Reduced Gravity Studies of Soret Transport Effects in Liquid Fuel Combustion

Science.gov (United States)

Shaw, Benjamin D.

2004-01-01

Soret transport, which is mass transport driven by thermal gradients, can be important in practical flames as well as laboratory flames by influencing transport of low molecular weight species (e.g., monatomic and diatomic hydrogen). In addition, gas-phase Soret transport of high molecular weight fuel species that are present in practical liquid fuels (e.g., octane or methanol) can be significant in practical flames (Rosner et al., 2000; Dakhlia et al., 2002) and in high pressure droplet evaporation (Curtis and Farrell, 1992), and it has also been shown that Soret transport effects can be important in determining oxygen diffusion rates in certain classes of microgravity droplet combustion experiments (Aharon and Shaw, 1998). It is thus useful to obtain information on flames under conditions where Soret effects can be clearly observed. This research is concerned with investigating effects of Soret transport on combustion of liquid fuels, in particular liquid fuel droplets. Reduced-gravity is employed to provide an ideal (spherically-symmetrical) experimental model with which to investigate effects of Soret transport on combustion. The research will involve performing reduced-gravity experiments on combustion of liquid fuel droplets in environments where Soret effects significantly influence transport of fuel and oxygen to flame zones. Experiments will also be performed where Soret effects are not expected to be important. Droplets initially in the 0.5 to 1 mm size range will be burned. Data will be obtained on influences of Soret transport on combustion characteristics (e.g., droplet burning rates, droplet lifetimes, gas-phase extinction, and transient flame behaviors) under simplified geometrical conditions that are most amenable to theoretical modeling (i.e., spherical symmetry). The experiments will be compared with existing theoretical models as well as new models that will be developed. Normal gravity experiments will also be performed.

Effects of ambient conditions on fuel cell vehicle performance

Science.gov (United States)

Haraldsson, K.; Alvfors, P.

Ambient conditions have considerable impact on the performance of fuel cell hybrid vehicles. Here, the vehicle fuel consumption, the air compressor power demand, the water management system and the heat loads of a fuel cell hybrid sport utility vehicle (SUV) were studied. The simulation results show that the vehicle fuel consumption increases with 10% when the altitude increases from 0 m up to 3000 m to 4.1 L gasoline equivalents/100 km over the New European Drive Cycle (NEDC). The increase is 19% on the more power demanding highway US06 cycle. The air compressor is the major contributor to this fuel consumption increase. Its load-following strategy makes its power demand increase with increasing altitude. Almost 40% of the net power output of the fuel cell system is consumed by the air compressor at the altitude of 3000 m with this load-following strategy and is thus more apparent in the high-power US06 cycle. Changes in ambient air temperature and relative humidity effect on the fuel cell system performance in terms of the water management rather in vehicle fuel consumption. Ambient air temperature and relative humidity have some impact on the vehicle performance mostly seen in the heat and water management of the fuel cell system. While the heat loads of the fuel cell system components vary significantly with increasing ambient temperature, the relative humidity did not have a great impact on the water balance. Overall, dimensioning the compressor and other system components to meet the fuel cell system requirements at the minimum and maximum expected ambient temperatures, in this case 5 and 40 °C, and high altitude, while simultaneously choosing a correct control strategy are important parameters for efficient vehicle power train management.

Benefits of barrier fuel on fuel cycle economics

International Nuclear Information System (INIS)

Crowther, R.L.; Kunz, C.L.

1988-01-01

Barrier fuel rod cladding was developed to eliminate fuel rod failures from pellet/cladding stress/corrosion interaction and to eliminate the associated need to restrict the rate at which fuel rod power can be increased. The performance of barrier cladding has been demonstrated through extensive testing and through production application to many boiling water reactors (BWRs). Power reactor data have shown that barrier fuel rod cladding has a significant beneficial effect on plant capacity factor and plant operating costs and significantly increases fuel reliability. Independent of the fuel reliability benefit, it is less obvious that barrier fuel has a beneficial effect of fuel cycle costs, since barrier cladding is more costly to fabricate. Evaluations, measurements, and development activities, however, have shown that the fuel cycle cost benefits of barrier fuel are large. This paper is a summary of development activities that have shown that application of barrier fuel significantly reduces BWR fuel cycle costs

Effect of mastication and other mechanical treatments on fuel structure in chaparral

Science.gov (United States)

Brennan, Teresa J.; Keeley, Jon E.

2015-01-01

Mechanical fuel treatments are a common pre-fire strategy for reducing wildfire hazard that alters fuel structure by converting live canopy fuels to a compacted layer of dead surface fuels. Current knowledge concerning their effectiveness, however, comes primarily from forest-dominated ecosystems. Our objectives were to quantify and compare changes in shrub-dominated chaparral following crushing, mastication, re-mastication and mastication-plus-burning treatments, and to assess treatment longevity. Results from analysis of variance (ANOVA) identified significant differences in all fuel components by treatment type, vegetation type and time since treatment. Live woody fuel components of height, cover and mass were positively correlated with time since treatment, whereas downed woody fuel components were negatively correlated. Herbaceous fuels, conversely, were not correlated, and exhibited a 5-fold increase in cover across treatment types in comparison to controls. Average live woody fuel recovery was 50% across all treatment and vegetation types. Differences in recovery between time-since-treatment years 1–8 ranged from 32–65% and exhibited significant positive correlations with time since treatment. These results suggest that treatment effectiveness is short term due to the rapid regrowth of shrubs in these systems and is compromised by the substantial increase in herbaceous fuels. Consequences of not having a full understanding of these treatments are serious and leave concern for their widespread use on chaparral-dominated landscapes.

Effect of ramp-cavity on hydrogen fueled scramjet combustor

Directory of Open Access Journals (Sweden)

J.V.S. Moorthy

2014-03-01

Full Text Available Sustained combustion and optimization of combustor are the two challenges being faced by combustion scientists working in the area of supersonic combustion. Thorough mixing, lower stagnation pressure losses, positive thrust and sustained combustion are the key issues in the field of supersonic combustion. Special fluid mechanism is required to achieve good mixing. To induce such mechanisms in supersonic inflows, the fuel injectors should be critically shaped incurring less flow losses. Present investigations are focused on the effect of fuel injection scheme on a model scramjet combustor performance. Ramps at supersonic flow generate axial vortices that help in macro-mixing of fuel with air. Interaction of shocks generated by ramps with the fuel stream generates boro-clinic torque at the air & liquid fuel interface, enhancing micro-mixing. Recirculation zones present in cavities increase the residence time of the combustible mixture. Making use of the advantageous features of both, a ramp-cavity combustor is designed. The combustor has two sections. First, constant height section consists of a backward facing step followed by ramps and cavities on both the top and bottom walls. The ramps are located alternately on top and bottom walls. The complete combustor width is utilized for the cavities. The second section of the combustor is diverging area section. This is provided to avoid thermal choking. In the present work gaseous hydrogen is considered as fuel. This study was mainly focused on the mixing characteristics of four different fuel injection locations. It was found that injecting fuel upstream of the ramp was beneficial from fuel spread point of view.

Fuel properties effect on the performance of a small high temperature rise combustor

Science.gov (United States)

Acosta, Waldo A.; Beckel, Stephen A.

1989-01-01

The performance of an advanced small high temperature rise combustor was experimentally determined at NASA-Lewis. The combustor was designed to meet the requirements of advanced high temperature, high pressure ratio turboshaft engines. The combustor featured an advanced fuel injector and an advanced segmented liner design. The full size combustor was evaluated at power conditions ranging from idle to maximum power. The effect of broad fuel properties was studied by evaluating the combustor with three different fuels. The fuels used were JP-5, a blend of Diesel Fuel Marine/Home Heating Oil, and a blend of Suntec C/Home Heating Oil. The fuel properties effect on the performance of the combustion in terms of pattern factor, liner temperatures, and exhaust emissions are documented.

Palliative effects of H2 on SOFCs operating with carbon containing fuels

Science.gov (United States)

Reeping, Kyle W.; Bohn, Jessie M.; Walker, Robert A.

2017-12-01

Chlorine can accelerate degradation of solid oxide fuel cell (SOFC) Ni-based anodes operating on carbon containing fuels through several different mechanisms. However, supplementing the fuel with a small percentage of excess molecular hydrogen effectively masks the degradation to the catalytic activity of the Ni and carbon fuel cracking reaction reactions. Experiments described in this work explore the chemistry behind the "palliative" effect of hydrogen on SOFCs operating with chlorine-contaminated, carbon-containing fuels using a suite of independent, complementary techniques. Operando Raman spectroscopy is used to monitor carbon accumulation and, by inference, Ni catalytic activity while electrochemical techniques including electrochemical impedance spectroscopy and voltammetry are used to monitor overall cell performance. Briefly, hydrogen not only completely hides degradation observed with chlorine-contaminated carbon-containing fuels, but also actively removes adsorbed chlorine from the surface of the Ni, allowing for the methane cracking reaction to continue, albeit at a slower rate. When hydrogen is removed from the fuel stream the cell fails immediately due to chlorine occupation of methane/biogas reaction sites.

Radiolysis effects on fuel corrosion within a failed nuclear waste container

International Nuclear Information System (INIS)

Sunder, S.; Shoeshmith, D.W.; Christensen, H.C.

2003-01-01

The concept of geological disposal of used nuclear fuel in corrosion resistant containers is being investigated in several countries. In the Canadian Nuclear Fuel Waste Management Program (CNFWMP), it is assumed that the used fuel will be disposed of in copper containers. Since the predicted lifetimes of these containers are very long (>106 years), only those containers emplaced with an undetected defect will fail within the period for which radionuclide release from the fuel must be considered. Early failure could lead to the entry of water into the container and subsequent release of radionuclides. The release rate of radionuclides from the used fuel will depend upon its dissolution rate. The primary mechanism for release will be the corrosion of the fuel driven by radiolytically-produced oxidants. The studies carried out to determine the effects of water radiolysis on fuel corrosion are reviewed, and some of the procedures used to predict corrosion rates of used fuel in failed nuclear waste containers described. (author)

Effects of fuel relocation on reflood in a partially-blocked rod bundle

Energy Technology Data Exchange (ETDEWEB)

Kim, Byoung Jae [School of Mechanical Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134 (Korea, Republic of); Kim, Jongrok; Kim, Kihwan; Bae, Sung Won [Thermal-Hydraulic Safety Research Division, Korea Atomic Energy Research Division, 111 Daedeok-daero, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Moon, Sang-Ki, E-mail: skmoon@kaeri.re.kr [Thermal-Hydraulic Safety Research Division, Korea Atomic Energy Research Division, 111 Daedeok-daero, Yuseong-gu, Daejeon 34057 (Korea, Republic of)

2017-02-15

Ballooning of the fuel rods has been an important issue, since it can influence the coolability of the rod bundle in a large-break loss-of-coolant accident (LBLOCA). Numerous past studies have investigated the effect of blockage geometry on the heat transfer in a partially blocked rod bundle. However, they did not consider the occurrence of fuel relocation and the corresponding effect on two-phase heat transfer. Some fragmented fuel particles located above the ballooned region may drop into the enlarged volume of the balloon. Accordingly, the fuel relocation brings in a local power increase in the ballooned region. The present study’s objective is to investigate the effect of the fuel relocation on the reflood under a LBLOCA condition. Toward this end, experiments were performed in a 5 × 5 partially-blocked rod bundle. Two power profiles were tested: one is a typical cosine shape and the other is the modified shape considering the effect of the fuel relocation. For a typical power shape, the peak temperature in the ballooned rods was lower than that in the intact rods. On the other hand, for the modified power shape, the peak temperature in the ballooned rods was higher than that in the intact rods. Numerical simulations were also performed using the MARS code. The tendencies of the peak clad temperatures were well predicted.

Effects of poison panel shrinkage and gaps on fuel storage rack reactivity

International Nuclear Information System (INIS)

Boyd, W.A.; Mueller, D.E.

1988-01-01

Fixed poison panels are used in spent fuel rack designs to increase enrichment limits and reduce cell spacing; therefore, assurances that the maximum rack reactivity will meet the design limit (0.95) throughout the lifetime of the racks depend on the continued effectiveness of the poison with time. Industry data have shown that poison panels will shrink under irradiated conditions. From recent data, however, poison panels have been found to have gaps spanning their width after relatively short operating periods. This paper presents results of studies showing the fuel rack reactivity changes associated with poison panel shrinkage and formation of gaps. The discovery of gaps in the fuel rack poison panels at an operating plant raises concerns regarding the effectiveness of the poison over the lifetime of the fuel racks. Studies performed to evaluate the effect of the poison panel shrinkage on reactivity show that reactivity changes from zero to several percent are possible depending on the initial panel size. Results of recent studies show that some gaps can be accommodated in the fuel rack poison panels at the fuel midplane without causing the fuel rack K eff limit to be exceeded. With worst-case assumptions concerning gap size and the number of panels affected, other actions will likely be required to show that the rack K eff design limit will not be exceeded

Fuel quality issues in stationary fuel cell systems.

Energy Technology Data Exchange (ETDEWEB)

Papadias, D.; Ahmed, S.; Kumar, R. (Chemical Sciences and Engineering Division)

2012-02-07

Fuel cell systems are being deployed in stationary applications for the generation of electricity, heat, and hydrogen. These systems use a variety of fuel cell types, ranging from the low temperature polymer electrolyte fuel cell (PEFC) to the high temperature solid oxide fuel cell (SOFC). Depending on the application and location, these systems are being designed to operate on reformate or syngas produced from various fuels that include natural gas, biogas, coal gas, etc. All of these fuels contain species that can potentially damage the fuel cell anode or other unit operations and processes that precede the fuel cell stack. These detrimental effects include loss in performance or durability, and attenuating these effects requires additional components to reduce the impurity concentrations to tolerable levels, if not eliminate the impurity entirely. These impurity management components increase the complexity of the fuel cell system, and they add to the system's capital and operating costs (such as regeneration, replacement and disposal of spent material and maintenance). This project reviewed the public domain information available on the impurities encountered in stationary fuel cell systems, and the effects of the impurities on the fuel cells. A database has been set up that classifies the impurities, especially in renewable fuels, such as landfill gas and anaerobic digester gas. It documents the known deleterious effects on fuel cells, and the maximum allowable concentrations of select impurities suggested by manufacturers and researchers. The literature review helped to identify the impurity removal strategies that are available, and their effectiveness, capacity, and cost. A generic model of a stationary fuel-cell based power plant operating on digester and landfill gas has been developed; it includes a gas processing unit, followed by a fuel cell system. The model includes the key impurity removal steps to enable predictions of impurity breakthrough

Effects of Fuel Oil on the Geotechnical Properties of Clay Soil

Directory of Open Access Journals (Sweden)

Mahdi Obaid Karkush

2017-08-01

Full Text Available The present study highlights the effects of medium fuel oil (MFO on the chemical, physical and mechanical properties of clay soil samples (disturbed and undisturbed obtained from the site of the electrical power plant in the campus of the University of Baghdad at Al-Jadriah district in Baghdad/Iraq. The soil sample was classified according to the unified soil classification system (USCS as CL and described as lean clay of low plasticity. The medium fuel oil is an industrial wastewater disposed as a byproduct from the fuel used in the electricity power plant. The soil samples are artificially contaminated with two percentages of medium fuel oil, 10 and 20 % related to the dry weight of soil. The soil samples were mixed with the contaminant (MFO by hand and then left for 4 days for homogeneity. A series of laboratory tests are conducted on both natural and artificially contaminated soil samples to measure the effects of medium fuel oil on the chemical, physical and mechanical properties of soil samples. The results of tests showed that the medium fuel oil has significant impacts on some properties of soil and slight effects on the others. Increasing the percentage of contaminant causes a slight decrease in the liquid limit and particle size distribution; on the other hand, it causes a considerable increase in the consolidation parameters and decrease in shear strength parameters. Also, there is a slight change in the chemical composition of soil samples.

EFFECT SIGNIFICANCE ASSESSMENT OF THE THERMODYNAMICAL FACTORS ON THE SOLID OXIDE FUEL CELL OPERATION

Directory of Open Access Journals (Sweden)

V. A. Sednin

2015-01-01

Full Text Available Technologies of direct conversion of the fuel energy into electrical power are an upcoming trend in power economy. Over the last decades a number of countries have created industrial prototypes of power plants on fuel elements (cells, while fuel cells themselves became a commercial product on the world energy market. High electrical efficiency of the fuel cells allows predictting their further spread as part of hybrid installations jointly with gas and steam turbines which specifically enables achieving the electrical efficiency greater than 70 %. Nevertheless, investigations in the area of increasing efficiency and reliability of the fuel cells continue. Inter alia, research into the effects of oxidizing reaction thermodynamic parameters, fuel composition and oxidation reaction products on effectiveness of the solid oxide fuel cells (SOFC is of specific scientific interest. The article presents a concise analysis of the fuel type effects on the SOFC efficiency. Based on the open publications experimental data and the data of numerical model studies, the authors adduce results of the statistical analysis of the SOFC thermodynamic parameters effect on the effectiveness of its functioning as well as of the reciprocative factors of these parameters and gas composition at the inlet and at the outlet of the cell. The presented diagrams reflect dimension of the indicated parameters on the SOFC operation effectiveness. The significance levels of the above listed factors are ascertained. Statistical analysis of the effects of the SOFC functionning process thermodynamical, consumption and concentration parameters demonstrates quintessential influence of the reciprocative factors (temperature – flow-rate and pressure – flow-rate and the nitrogen N2 and oxygen O2 concentrations on the operation efficiency in the researched range of its functioning. These are the parameters to be considered on a first-priority basis while developing mathematical models

The effect of conservation tillage forward speed and depth on farm fuel consumption

Directory of Open Access Journals (Sweden)

A Jalali

2015-09-01

Full Text Available Introduction: In recent years, production techniques and equipment have been developed for conservation tillage systems that have been adopted by many farmers. With proper management, overall yield averages for conventional and reduced tillage systems are nearly identical. Sometimes, field operations can be combined by connecting two or more implements. Much research has focused on either reducing or eliminating tillage operations to develop sustainable crop production methods. The greatest costs in farm operations are associated with tillage due to greater specific energy requirement in tillage and the high fuel costs. Combined operations reduce both fuel consumption and time and labor requirements by eliminating at least one individual trip over the field. Light tillage, spraying, or fertilizing operations can be combined with eitherprimary or secondary tillage or planting operations. The amount of fuel saved depends on the combined operations. Generally, light tillage, spraying, and fertilizing operations consume between 0.25 and 0.50 gallons of diesel fuel per acre. Fuel savings of 0.12 to 0.33 gallons per acre can usually be expected from combining operations. Eliminating one primary tillage operation and combining one light tillage, spraying, or fertilizing operation with another tillage or planting operation can usually save at least a gallon of diesel fuel per acre. Combining operations has the added benefit of reducing wheel traffic and compaction. To improve the tillage energy efficiency, implementing effective and agronomic strategies should be improved. Different tillage systems should be tested to determine the most energy efficient ones. Tillage helps seed growth and germination through providing appropriate conditions for soil to absorb sufficient temperature and humidity. Tillage is a time consuming and expensive procedure. With the application of agricultural operations, we can save considerable amounts of fuel, time and

Fossil fuel and biomass burning effect on climate - heating or cooling

Energy Technology Data Exchange (ETDEWEB)

Kaufman, Y.J.; Fraser, R.S.; Mahoney, R.L. (NASA/Goddard Space Flight Center, Greenbelt, MD (USA))

1991-06-01

Emission from burning of fossil fuels and biomass (associated with deforestation) generates a radiative forcing on the atmosphere and a possible climate change. Emitted trace gases heat the atmosphere through their greenhouse effect, while particulates formed from emitted SO{sub 2} cause cooling by increasing cloud albedos through alteration of droplet size distributions. This paper reviews the characteristics of the cooling effect and applies Twomey's theory to check whether the radiative balance favours heating or cooling for the cases of fossil fuel and biomass burning. It is also shown that although coal and oil emit 120 times as many CO{sub 2} molecules as SO{sub 2} molecules, each SO{sub 2} molecule is 50-1100 times more effective in cooling the atmosphere (through the effect of aerosol particles on cloud albedo) than a CO{sub 2} molecule is in heating it. Note that this ratio accounts for the large difference in the aerosol (3-10 days) and CO{sub 2} (7-100 years) lifetimes. It is concluded, that the cooling effect from coal and oil burning may presently range from 0.4 to 8 times the heating effect. Within this large uncertainty, it is presently more likely that fossil fuel burning causes cooling of the atmosphere rather than heating. Biomass burning associated with deforestation, on the other hand, is more likely to cause heating of the atmosphere than cooling since its aerosol cooling effect is only half that from fossil fuel burning and its heating effect is twice as large. Future increases in coal and oil burning, and the resultant increase in concentration of cloud condensation nuclei, may saturate the cooling effect, allowing the heating effect to dominate. For a doubling in the CO{sub 2} concentration due to fossil fuel burning, the cooling effect is expected to be 0.1 to 0.3 of the heating effect. 75 refs., 8 tabs.

A comparison study on radioactive waste management effectiveness in various nuclear fuel cycles

International Nuclear Information System (INIS)

Ko, Won Il; Kim, Ho Dong

2001-07-01

This study examines whether the DUPIC (Direct Use of Spent PWR Fuel In CANDU) fuel cycle make radioactive waste management more effective, by comparing it with other fuel cycles such as the PWR (Pressurized Water Reactor) once-through cycle, the HWR (Pressurized Heavy Water Reactor) once-through cycle and the thermal recycling option to use an existing PWR with MOX (Mixed Oxide) fuel. This study first focuses on the radioactive waste volume generated in all fuel cycle steps, which could be one of the measures of effectiveness of the waste management. Then the total radioactive waste disposition cost is estimated based on two units measuring; m3/GWe-yr and US$/GWe-yr. We find from the radioactive waste volume estimation that the DUPIC fuel cycle could have lower volumes for milling tailings, low level waste and spent fuel than those of other fuel cycle options. From the results of the disposition cost analysis, we find that the DUPIC waste disposition cost is the lowest among fuel cycle options. If the total waste disposition cost is used as a proxy for quantifying the easiness or difficulty in managing wastes, then the DUPIC option actually make waste management easier

Effect of flexible fuels on mechanical properties of reinforced polyoxymethylenes (POM

Directory of Open Access Journals (Sweden)

M. Gómez-Mares

2014-08-01

Full Text Available The use of flexible fuels has been increased during the last years making essential to run compatibility tests with those materials exposed to them. In this work the effect of the flexible fuels M15A (Volume Mixture of 85% fuel C and 15 % Aggressive methanol and M30A (Volume mixture of 70% fuel C and 30 % Aggressive methanol on the mechanical properties of some polymers of the Polyoxymethylene (POM family is assessed. The polymers chosen had different levels of glass fiber filler (0, 10 and 25%. The samples were immersed on fuel and kept on a chamber at 80°C during 1008h. The results showed that the properties of polymers with filler are more affected than the ones of the polymers without it. Tensile stress at break and Tensile stress at yield diminished with the fuel exposure. The most aggressive fuel was found to be M30A, due to the higher methanol concentration.

Effects of cold worked and fully annealed claddings on fuel failure behaviour

International Nuclear Information System (INIS)

Saito, Shinzo; Hoshino, Hiroaki; Shiozawa, Shusaku; Yanagihara, Satoshi

1979-12-01

Described are the results of six differently heat-treated Zircaloy clad fuel rod tests in NSRR experiments. The purpose of the test is to examine the extent of simulating irradiated claddings in mechanical properties by as-cold worked ones and also the effect of fully annealing on the fuel failure bahaviour in a reactivity initiated accident (RIA) condition. As-cold worked cladding does not properly simulated the embrittlement of the irradiated one in a RIA condition, because the cladding is fully annealed before the fuel failure even in the short transient. Therefore, the fuel behaviour such as fuel failure threshold energy, failure mechanism, cladding deformation and cladding oxidation of the fully annealed cladding fuel, as well as that of the as-cold worked cladding fuel, are not much different from that of the standard stress-relieved cladding fuel. (author)

Water confinement effects in response of fuel assembly to faulted condition loads

International Nuclear Information System (INIS)

Shah, S.J.; Brenneman, B.; Williams, G.T.; Strumpel, J.H.

2004-01-01

It has been established by other authors that the accelerations of the water confined by the reactor core baffle plates has a significant effect on the responses of all the fuel assemblies during LOCA (loss of coolant accident) or seismic transients. This particular effect is a consequence of the water being essentially incompressible, and thus experiencing the same horizontal accelerations as the imposed baffle plate motions. These horizontal accelerations of the fluid induce lateral pressure gradients that cause horizontal buoyancy forces on any submerged structures. These forces are in the same direction as the baffle accelerations and, for certain frequencies at least, tend to reduce the relative displacements between the fuel and baffle plates. But there is another confinement effect: the imposed baffle plate velocities must also be transmitted to the water. If the fuel assembly grid strips are treated as simple hydro-foils, these horizontal velocity components change the fluid angle of attack on each strip, and thus may induce large horizontal lift forces on each grid in the same direction as the baffle plate velocity. There is a similar horizontal lift due to inclined flow over the rods when axial flow is present. These combined forces appear to reduce the relative displacements between the fuel and baffle plates for any significant axial flow velocity. Modeling this effect is very simple. It was shown in previous papers that the mechanism for the large fuel assembly damping due to axial flow may be the hydrodynamic forces on the grid strips, and that this is very well represented by discrete viscous dampers at each grid elevation. To include the imposed horizontal water velocity effects, on both the grids and rods, these dampers are simply attached to the baffle plate rather than 'ground'. The large flow-induced damping really acts in a relative reference frame rather than an inertial reference frame, and thus it becomes a flow-induced coupling between the

Corrosion effect of fast reactor fuel claddings on their mechanical properties

International Nuclear Information System (INIS)

Davydov, E.F.; Krykov, F.N.; Shamardin, V.K.

1985-01-01

Fast reactor fuel cladding corrosion effect on its mechanical properties was investigated. UO 2 fuel elements were irradiated in the BOP-60 reactor at the linear heat rate of 42 kw/m. Fuel cladding is made of stainless steel OKh16N15M3BR. Calculated maximum cladding temperature is 920 K. Neutron fluence in the central part of fuel elements is 6.3x10 26 m+H- 2 . To investigate the strength changes temperature dependence of corrossion depth, cladding strength reduction factors was determined. Samples plasticity reduction with corrosion layer increase is considered to be a characteristic feature

Effects of Fuel Ethanol Use on Fuel-Cycle Energy and Greenhouse Gas Emissions

International Nuclear Information System (INIS)

C. Saricks; D. Santini; M. Wang

1999-01-01

We estimated the effects on per-vehicle-mile fuel-cycle petroleum use, greenhouse gas (GHG) emissions, and energy use of using ethanol blended with gasoline in a mid-size passenger car, compared with the effects of using gasoline in the same car. Our analysis includes petroleum use, energy use, and emissions associated with chemicals manufacturing, farming of corn and biomass, ethanol production, and ethanol combustion for ethanol; and petroleum use, energy use, and emissions associated with petroleum recovery, petroleum refining, and gasoline combustion for gasoline. For corn-based ethanol, the key factors in determining energy and emissions impacts include energy and chemical usage intensity of corn farming, energy intensity of the ethanol plant, and the method used to estimate energy and emissions credits for co-products of corn ethanol. The key factors in determining the impacts of cellulosic ethanol are energy and chemical usage intensity of biomass farming, ethanol yield per dry ton of biomass, and electricity credits in cellulosic ethanol plants. The results of our fuel-cycle analysis for fuel ethanol are listed below. Note that, in the first half of this summary, the reductions cited are per-vehicle-mile traveled using the specified ethanol/gasoline blend instead of conventional (not reformulated) gasoline. The second half of the summary presents estimated changes per gallon of ethanol used in ethanol blends. GHG emissions are global warming potential (GWP)-weighted, carbon dioxide (CO2)-equivalent emissions of CO2, methane (CH4), and nitrous oxide (N2O)

10 CFR 51.52 - Environmental effects of transportation of fuel and waste-Table S-4.

Science.gov (United States)

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Environmental effects of transportation of fuel and waste... Environmental effects of transportation of fuel and waste—Table S-4. Under § 51.50, every environmental report... detailed analysis of the environmental effects of transportation of fuel and wastes to and from the reactor...

Current state of knowledge in radiolysis effects on spent fuel corrosion

International Nuclear Information System (INIS)

Christensen, H.; Sunder, S.

1998-09-01

Literature data on the effect of water radiolysis products on spent fuel oxidation and dissolution have been reviewed. Effects of γ-radiolysis, α-radiolysis and dissolved O 2 or H 2 O 2 in unirradiated solutions have been discussed separately. Also the effect of carbonate in γ-irradiated solutions and radiolysis effects on leaching of spent fuels have been reviewed. In addition a radiolysis model for calculation of corrosion rates of UO 2 , presented previously, has been discussed. The model has been shown to give a good agreement between calculated and measured corrosion rates in the case of γ-radiolysis and in unirradiated solutions of dissolved oxygen or hydrogen peroxide. The model has failed to predict the results of α-radiolysis. In a recent study it was shown that the model gave a good agreement with measured corrosion rates of spent fuel exposed in deionized water

Measurement of fuel importance distribution in non-uniformly distributed fuel systems

International Nuclear Information System (INIS)

Yamane, Yoshihiro; Hirano, Yasushi; Yasui, Hazime; Izima, Kazunori; Shiroya, Seiji; Kobayashi, Keiji.

1995-01-01

A reactivity effect due to a spatial variation of nuclear fuel concentration is an important problem for nuclear criticality safety in a reprocessing plant. As a theory estimating this reactivity effect, the Goertzel and fuel importance theories are well known. It has been shown that the Goertzel's theory is valid in the range of our experiments based on measurements of reactivity effect and thermal neutron flux in non-uniformly distributed fuel systems. On the other hand, there have been no reports concerning systematic experimental studies on the flatness of fuel importance which is a more general index than the Goertzel's theory. It is derived from the perturbation theory that the fuel importance is proportional to the reactivity change resulting from a change of small amount of fuel mass. Using a uniform and three kinds of nonuniform fuel systems consisting of 93.2% enriched uranium plates and polyethylene plates, the fuel importance distributions were measured. As a result, it was found experimentally that the fuel importance distribution became flat, as its reactivity effect became large. Therefore it was concluded that the flatness of fuel importance distribution is the useful index for estimating reactivity effect of non-uniformly distributed fuel system. (author)

Effect of wood fuels on power plant operability

International Nuclear Information System (INIS)

Orjala, M.; Ingalsuo, R.

2001-01-01

The objective of the research is to determine the critical properties of wood fuels on the basis of power plant operability, to determine the optimal conditions for reduction of harmful detriments, and to study how the storage and processing of wood fuels effect on the operability. Both the CFB and BFB technologies are studied. The project started in December 2000 and it will be ended by the end of 2002. Experts of the Fuels and Combustion research field of VTT Energy carry out the main parts of the research. Experts of the research field of Mineral Processing of VTT Chemical Technology, located in Outokumpu, and Kemian tutkimuspalvelut Oy/Oulu University, located in Outokumpu, participate in the analytics, and the research field of Materials and Manufacturing Technology of VTT Manufacturing Technology in Otaniemi participates in the research on material effects. System Technology Laboratory of Oulu University carries out the power plant automation and boiler control technology research under supervision of Professor Urpo Kortela. Co-operation with the materials research unit of EU's JRC, located in Petten, which started in the research 'Combustion of Forest Chips', will be continues in this research. Co-operation will be made with Swedish Vaermeforsk in the field of information exchange on experiences in utilisation of wood fuels in Swedish power plants and possibilities to join in the projects of Vaermeforsk in this research field. Following companies participate in the project: Etelae-Savon Energia Oy, Foster Wheeler Energia Oy, Kvaerner Pulping Oy, Simpele pasteboard factory of M-Real Oyj and Vaermeforsk AB (Sweden). (orig.)

Effect of Pu-rich agglomerate in MOX fuel on a lattice calculation

International Nuclear Information System (INIS)

Kawashima, Katsuyuki; Yamamoto, Toru; Namekawa, Masakazu

2007-01-01

The effect of Pu-rich agglomerates in U-Pu mixed oxide (MOX) fuel on a lattice calculation has been demonstrated. The Pu-rich agglomerate parameters are defined based on the measurement data of MIMAS-MOX and the focus is on the highly enriched MOX fuel in accordance with increased burnup resulting in a higher volume fraction of the Pu-rich agglomerates. The lattice calculations with a heterogeneous fuel model and a homogeneous fuel model are performed simulating the PWR 17x17 fuel assembly. The heterogeneous model individually treats the Pu-rich agglomerate and U-Pu matrix, whereas the homogeneous model homogenizes the compositions within the fuel pellet. A continuous-energy Monte Carlo burnup code, MVP-BURN, is used for burnup calculations up to 70 GWd/t. A statistical geometry model is applied in modeling a large number of Pu-rich agglomerates assuming that they are distributed randomly within the MOX fuel pellet. The calculated nuclear characteristics include k-inf, Pu isotopic compositions, power density and burnup of the Pu-rich agglomerates, as well as the pellet-averaged Pu compositions as a function of burnup. It is shown that the effect of Pu-rich agglomerates on the lattice calculation is negligibly small. (author)

Effects of chemical equilibrium on turbine engine performance for various fuels and combustor temperatures

Science.gov (United States)

Tran, Donald H.; Snyder, Christopher A.

1992-01-01

A study was performed to quantify the differences in turbine engine performance with and without the chemical dissociation effects for various fuel types over a range of combustor temperatures. Both turbojet and turbofan engines were studied with hydrocarbon fuels and cryogenic, nonhydrocarbon fuels. Results of the study indicate that accuracy of engine performance decreases when nonhydrocarbon fuels are used, especially at high temperatures where chemical dissociation becomes more significant. For instance, the deviation in net thrust for liquid hydrogen fuel can become as high as 20 percent at 4160 R. This study reveals that computer central processing unit (CPU) time increases significantly when dissociation effects are included in the cycle analysis.

Effect analysis of air introduced by pressurization on fuel rod performances

International Nuclear Information System (INIS)

Ren Qisen; Liu Tong; Sheng Guofu

2012-01-01

In the process of pressurization and seal welding, it is common practice to vacuumize before gas filling for the sake of preventing introducing air and other impurities, which would affect the gas composition inside of the fuel rod. However, vacuumization during pressurization is likely not being required sometimes in order to simplify the fabrication procedure. In the present work, based on the AFA3G fuel rod design with 2 MPa of filling gas, analyses on fuel rod performances were carried out under the condition of pressurization with and without vacuumization, respectively. Furthermore, the effect on hydrogen content in fuel rod was preliminarily discussed. Results indicate that the impacts of air composition introduced by pressurization on fuel rod thermal-mechanical performances, such as internal pressure and fuel center temperature, were extremely slight. The gap conductance varies to some extent as a result of the change of gas composition due to air introduced in fuel rod. The impact of humidity on water content in fuel rod is negligible at a low temperature of around 25℃. However, at higher temperature, it is essential to pay attention on the control of fabrication process, and prevent much moisture entering into the fuel rod and increasing the probability of hydriding failure. (authors)

Fuel assemblies

International Nuclear Information System (INIS)

Nagano, Mamoru; Yoshioka, Ritsuo

1983-01-01

Purpose: To effectively utilize nuclear fuels by increasing the reactivity of a fuel assembly and reduce the concentration at the central region thereof upon completion of the burning. Constitution: A fuel assembly is bisected into a central region and a peripheral region by disposing an inner channel box within a channel box. The flow rate of coolants passing through the central region is made greater than that in the peripheral region. The concentration of uranium 235 of the fuel rods in the central region is made higher. In such a structure, since the moderating effect in the central region is improved, the reactivity of the fuel assembly is increased and the uranium concentration in the central region upon completion of the burning can be reduced, fuel economy and effective utilization of uranium can be attained. (Kamimura, M.)

Effects of coal-derived trace species on performance of molten carbonate fuel cells

Energy Technology Data Exchange (ETDEWEB)

1992-05-01

The Carbonate Fuel Cell is a very promising option for highly efficient generation of electricity from many fuels. If coal-gas is to be used, the interactions of coal-derived impurities on various fuel cell components need to be understood. Thus the effects on Carbonate Fuel Cell performance due to ten different coal-derived contaminants viz., NH{sub 3}, H{sub 2}S, HC{ell}, H{sub 2}Se, AsH{sub 3}, Zn, Pb, Cd, Sn, and Hg, have been studied at Energy Research Corporation. Both experimental and theoretical evaluations were performed, which have led to mechanistic insights and initial estimation of qualitative tolerance levels for each species individually and in combination with other species. The focus of this study was to investigate possible coal-gas contaminant effects on the anode side of the Carbonate Fuel Cell, using both out-of-cell thermogravimetric analysis by isothermal TGA, and fuel cell testing in bench-scale cells. Separate experiments detailing performance decay in these cells with high levels of ammonia contamination (1 vol %) and with trace levels of Cd, Hg, and Sn, have indicated that, on the whole, these elements do not affect carbonate fuel cell performance. However, some performance decay may result when a number of the other six species are present, singly or simultaneously, as contaminants in fuel gas. In all cases, tolerance levels have been estimated for each of the 10 species and preliminary models have been developed for six of them. At this stage the models are limited to isothermal, benchscale (300 cm{sup 2} size) single cells. The information obtained is expected to assist in the development of coal-gas cleanup systems, while the contaminant performance effects data will provide useful basic information for modeling fuel cell endurance in conjunction with integrated gasifier/fuel-cell systems (IGFC).

Power Peaking Effect of OTTO Fuel Scheme Pebble Bed Reactor

Science.gov (United States)

Setiadipura, T.; Suwoto; Zuhair; Bakhri, S.; Sunaryo, G. R.

2018-02-01

Pebble Bed Reactor (PBR) type of Hight Temperature Gas-cooled Reactor (HTGR) is a very interesting nuclear reactor design to fulfill the growing electricity and heat demand with a superior passive safety features. Effort to introduce the PBR design to the market can be strengthen by simplifying its system with the Once-through-then-out (OTTO) cycle PBR in which the pebble fuel only pass the core once. Important challenge in the OTTO fuel scheme is the power peaking effect which limit the maximum nominal power or burnup of the design. Parametric survey is perform in this study to investigate the contribution of different design parameters to power peaking effect of OTTO cycle PBR. PEBBED code is utilized in this study to perform the equilibrium PBR core analysis for different design parameter and fuel scheme. The parameters include its core diameter, height-per-diameter (H/D), power density, and core nominal power. Results of this study show that diameter and H/D effectsare stronger compare to the power density and nominal core power. Results of this study might become an importance guidance for design optimization of OTTO fuel scheme PBR.

Thermochemical modeling of nuclear fuel and the effects of oxygen potential buffers

Energy Technology Data Exchange (ETDEWEB)

Loukusa, Henri, E-mail: henri.loukusa@vtt.fi; Ikonen, Timo; Valtavirta, Ville; Tulkki, Ville

2016-12-01

The elemental and chemical composition of nuclear fuel pellets are key factors influencing the material properties of the pellets. The oxidation state of the fuel is one of the most important chemical properties influencing the material properties of the fuel, and it can only be determined with the knowledge of the chemical composition. A measure of the oxidation state is the oxygen chemical potential of the fuel. It can be buffered by redox pairs, such as the well-known Mo/MoO{sub 2} pair. In this work, the elemental composition of the fuel is obtained from a burnup calculation and the temperature and pressure calculated with a fuel performance code. An estimate of the oxygen potential of fuel is calculated with Gibbs energy minimization. The results are compared against experimental data from the literature. The significance of the UMoO{sub 6} compound and its buffering effect on the oxygen potential is emphasized. - Highlights: • A Gibbs energy minimization routine has been developed for nuclear fuel modeling. • The initial stoichiometry affects the development of the oxygen potential of fuel. • UMoO{sub 6} is found to buffer the oxygen potential of nuclear fuel.

The effect of fuel burnup and dispersed water intrusion on the criticality of spent high-level nuclear fuel in a geologic repository

International Nuclear Information System (INIS)

Culbreth, W.G.; Zielinski, P.R.

1994-01-01

Studies of the spent fuel waste package have been conducted through the use of a Monte-Carlo neutron simulation program to determine the ability of the fuel to sustain a chain reaction. These studies have included fuel burnup and the effect of water mists on criticality. Results were compared with previous studies. In many criticality studies of spent fuel waste packages, fresh fuel with an enrichment as high as 4.5% is used as the conservative (worst) case. The actual spent fuel has a certain amount of burnup that decreases the concentration of fissile uranium and increases the amount of radionuclides present. The LWR Radiological Data Base from OCRWM has been used to determine the relative radionuclide ratios and KENO 5.1 was used to calculate values of the effective multiplication factor, k eff . Spent fuel is not capable of sustaining a chain reaction unless a suitable moderator, such as water, is present. A completely flooded container has been treated as the worst case for criticality. Results of a previous report that demonstrated that k eff actually peaked at a water-to-mixture ratio of 13% were analyzed for validity. In the present study, these results did not occur in the SCP waste package container

Current state of knowledge of water radiolysis effects on spent nuclear fuel corrosion

International Nuclear Information System (INIS)

Christensen, H.; Sunder, S.

2000-07-01

Literature data on the effect of water radiolysis products on spent-fuel oxidation and dissolution are reviewed. Effects of gamma radiolysis, alpha radiolysis, and dissolved O 2 or H 2 O 2 in unirradiated solutions are discussed separately. Also, the effect of carbonate in gamma-irradiated solutions and radiolysis effects on leaching of spent fuel are reviewed. In addition, a kinetic model for calculating the corrosion rates of UO 2 in solutions undergoing radiolysis is discussed. The model gives good agreement between calculated and measured corrosion rates in the case of gamma radiolysis and in unirradiated solutions containing dissolved oxygen or hydrogen peroxide. However, the model fails to predict the results of alpha radiolysis. In a recent study , it was shown that the model gave good agreement with measured corrosion rates of spent fuel exposed in deionized water. The applications of radiolysis studies for geologic disposal of used nuclear fuel are discussed. (author)

Effect of energy taxation on fuel choice and emissions

International Nuclear Information System (INIS)

Leino, P.; Kosunen, P.; Rauhamaeki, J.

1997-01-01

The aim of the project was to study how various tax models for power plant fuels affect the fuel consumption and emissions of particles, sulphur dioxide (SO 2 ), nitrogen oxide (NO x ) and carbon dioxide (CO 2 ). First, the development of Finnish energy taxation is discussed, followed by a survey of the energy production structure for 1994. For this purpose, it was necessary to prepare a large boiler database, which covers about 95 % of the fuel consumption of Finnish energy production. The boiler database was used to calculate the emissions of particles, SO 2 , NO x and CO 2 in 1994. The year 2010 selected under review is the year by which the Ministry of Trade and Industry has prepared their primary energy consumption estimates. Four different alternatives were studied as future tax models. In the first alternative taxation would be as it in years 1995-1996 and in the second alternative taxation would be as in January 1997. In the third alternative the Finnish application of EU taxes would be in force in full, i.e., the tax on heavy fuel oil would be 10 US dollars a barrel. In the fourth alternative there would be no taxes on fuels. The boiler database was used to find out how the consumption distribution of the fuels used in 2010 would change in the various tax models. The tax models affect most the position of fuel peat and natural gas in Finland. If the EU alternative, which is favourable for fuel peat and natural gas, comes true, the consumption of fuel peat will grow by two thirds and the consumption of natural gas will more than double from the present level. If the taxation is as 1 January 1997, the consumption of peat will remain the same as today and the consumption of natural gas will grow by about 50 %. However, if there are no taxes on fuels, the consumption of fuel peat will fall by almost a third and the consumption of natural gas will remain the same as expected at the existing and planned plants. The effect of the various tax models on emissions

Obesity-related health impacts of fuel excise taxation- an evidence review and cost-effectiveness study.

Science.gov (United States)

Brown, V; Moodie, M; Cobiac, L; Mantilla Herrera, A M; Carter, R

2017-05-04

Reducing automobile dependence and improving rates of active transport may reduce the impact of obesogenic environments, thereby decreasing population prevalence of obesity and other diseases where physical inactivity is a risk factor. Increasing the relative cost of driving by an increase in fuel taxation may therefore be a promising public health intervention for obesity prevention. A scoping review of the evidence for obesity or physical activity effect of changes in fuel price or taxation was undertaken. Potential health benefits of an increase in fuel excise taxation in Australia were quantified using Markov modelling to simulate obesity, injury and physical activity related health impacts of a fuel excise taxation intervention for the 2010 Australian population. Health adjusted life years (HALYs) gained and healthcare cost savings from diseases averted were estimated. Incremental cost-effectiveness ratios (ICERs) were reported and results were tested through sensitivity analysis. Limited evidence on the effect of policies such as fuel taxation on health-related behaviours currently exists. Only three studies were identified reporting associations between fuel price or taxation and obesity, whilst nine studies reported associations specifically with physical activity, walking or cycling. Estimates of the cross price elasticity of demand for public transport with respect to fuel price vary, with limited consensus within the literature on a probable range for the Australian context. Cost-effectiveness modelling of a AUD0.10 per litre increase in fuel excise taxation using a conservative estimate of cross price elasticity for public transport suggests that the intervention would be cost-effective from a limited societal perspective (237 HALYs gained, AUD2.6 M in healthcare cost savings), measured against a comparator of no additional increase in fuel excise. Under "best case" assumptions, the intervention would be more cost-effective (3181 HALYs gained, AUD34.2�

Effect study of multi-bubbles on stress distribution of fuel particle

International Nuclear Information System (INIS)

Zhao Yi; Wang Xiaomin; Long Chongsheng

2015-01-01

The finite element model was proposed to simulate the process of the UO_2 dispersion fuel particle sustaining the internal pressure of multi-bubbles, and the stress distribution of fuel particle with intra-bubbles was calculated. The results show that when the bubbles line equidistantly along x axis, the max normal stress along y axis increases with the number of bubbles, meanwhile, the increment of the normal stress gradually decreases. There is a limit that the effect of bubble's number imposes on the max normal stress in the fuel particle. When multi-column of bubbles exist, the max normal stress along x axis in the fuel particle increases, and the max normal stress along y axis decreases with the increase of the number of bubble column. The stress concentration in the fuel particle decreases with the spacing radius ratio increasing. (authors)

Effect of Crossflow on Hot Spot Fuel Temperature in Prismatic VHTR

International Nuclear Information System (INIS)

Lee, Sung Nam; Tak, Nam-il; Kim, Min Hwan; Noh, Jae Man; Park, Goon-Cherl

2014-01-01

Various studies have been conducted to predict the thermal-hydraulics of a prismatic gas-cooled reactor. However, most previous studies have concentrated on the nominal-designed core. The fuel assembly of a high temperature gas-cooled reactor consists of a fuel compact and graphite block used as a moderator. This graphite faces a dimensional change due to irradiation or heating during normal operation. This size change might affect the coolant flow distribution in the active core. Therefore, the hot spot fuel temperature position or value could vary. There are two types of flows by the size change of graphite. One is the bypass flow and the other is the crossflow. The crossflow occurs at the crossflow gap between the vertical stacks of fuel blocks. In this study, the effect of the crossflow on the hot spot fuel temperature has been intensively investigated. (author)

Study Of The Fuel Cycle Effect To The Electricity Generating Cost

International Nuclear Information System (INIS)

Salimy, D. H.

1998-01-01

The nuclear fuel cycle cost contributes relatively small fraction to the total nuclear power generation cost, I.e. about 15 to 30%, compared to the fuel cost in the coal-generated electricity (40-60%). Or in the oil-generated electricity (70-80%). This situation will give effect that the future generation cost is much less sensitive to the changes in the fuel prince than in the case of fossil fuel power plants. The study has shown that by assuming a 100% increase in the natural uranium price, the total nuclear fuel cycle cost would increase only by about 27% and in turn it contributes about 29% increase to the total nuclear fuel cycle cost. As a result, it contributes only 4 to 8% increase in the nuclear energy generation cost. As a comparison, if the same situation should occur to fossil fuel plants, the assumed fuel price increase would have increased the electricity generating cost by about 40-65% for coal-fired plants, and about 70-85% for oil-fired plants. This study also has assesses the economic aspects of the electricity generating cots for nuclear power plant (NPP) and the coal power plant. For an NPP the most affecting factor is the investment cost, while for the coal power plant, the major factor influencing the total cost is the price/cost of the fuel

Development of an analytical model to assess fuel property effects on combustor performance

Science.gov (United States)

Sutton, R. D.; Troth, D. L.; Miles, G. A.; Riddlebaugh, S. M.

1987-01-01

A generalized first-order computer model has been developed in order to analytically evaluate the potential effect of alternative fuels' effects on gas turbine combustors. The model assesses the size, configuration, combustion reliability, and durability of the combustors required to meet performance and emission standards while operating on a broad range of fuels. Predictions predicated on combustor flow-field determinations by the model indicate that fuel chemistry, as defined by hydrogen content, exerts a significant influence on flame retardation, liner wall temperature, and smoke emission.

The determinants of fuel use in the trucking industry - volume, fleet characteristics and the rebound effect

DEFF Research Database (Denmark)

de Borger, Bruno; Mulalic, Ismir

2012-01-01

This paper studies the determinants of fuel use in the trucking industry in Denmark, using aggregate time series data for the period 1980–2007. The model captures the main linkages between the demand for freight transport, the characteristics of the vehicle fleet, and the demand for fuel. Results...... of this effect is approximately 10% in the short run and 17% in the long run, so that a 1% improvement in fuel efficiency reduces fuel use by 0.90% (short-run) to 0.83% (long-run). Second, we find that higher fuel prices raise the average capacity of trucks, and they induce firm sto invest in newer, typically...... more fuel efficient, trucks. Third, these adjustments and the rebound effect jointly imply that the effect of higher fuel prices on fuel use in the trucking industry is fairly small; estimated price elasticities are _0:13 and _0:22 in the short run and in the long run, respectively. The empirical...

Effects of the biodiesel blend fuel on aldehyde emissions from diesel engine exhaust

Science.gov (United States)

Peng, Chiung-Yu; Yang, Hsi-Hsien; Lan, Cheng-Hang; Chien, Shu-Mei

Interest in use of biodiesel fuels derived from vegetable oils or animal fats as alternative fuels for petroleum-based diesels has increased due to biodiesels having similar properties of those of diesels, and characteristics of renewability, biodegradability and potential beneficial effects on exhaust emissions. Generally, exhaust emissions of regulated pollutants are widely studied and the results favor biodiesels on CO, HC and particulate emissions; however, limited and inconsistent data are showed for unregulated pollutants, such as carbonyl compounds, which are also important indicators for evaluating available vehicle fuels. For better understanding biodiesel, this study examines the effects of the biodiesel blend fuel on aldehyde chemical emissions from diesel engine exhausts in comparison with those from the diesel fuel. Test engines (Mitsubishi 4M40-2AT1) with four cylinders, a total displacement of 2.84 L, maximum horsepower of 80.9 kW at 3700 rpm, and maximum torque of 217.6 N m at 2000 rpm, were mounted and operated on a Schenck DyNAS 335 dynamometer. Exhaust emission tests were performed several times for each fuel under the US transient cycle protocol from mileages of 0-80,000 km with an interval of 20,000 km, and two additional measurements were carried out at 40,000 and 80,000 km after maintenance, respectively. Aldehyde samples were collected from diluted exhaust by using a constant volume sampling system. Samples were extracted and analyzed by the HPLC/UV system. Dominant aldehydes of both fuels' exhausts are formaldehyde and acetaldehyde. These compounds together account for over 75% of total aldehyde emissions. Total aldehyde emissions for B20 (20% waste cooking oil biodiesel and 80% diesel) and diesel fuels are in the ranges of 15.4-26.9 mg bhp-h -1 and 21.3-28.6 mg bhp-h -1, respectively. The effects of increasing mileages and maintenance practice on aldehyde emissions are insignificant for both fuels. B20 generates slightly less emission than

Effects of Fuel Ethanol Use on Fuel-Cycle Energy and Greenhouse Gas Emissions; TOPICAL

International Nuclear Information System (INIS)

C. Saricks; D. Santini; M. Wang

1999-01-01

We estimated the effects on per-vehicle-mile fuel-cycle petroleum use, greenhouse gas (GHG) emissions, and energy use of using ethanol blended with gasoline in a mid-size passenger car, compared with the effects of using gasoline in the same car. Our analysis includes petroleum use, energy use, and emissions associated with chemicals manufacturing, farming of corn and biomass, ethanol production, and ethanol combustion for ethanol; and petroleum use, energy use, and emissions associated with petroleum recovery, petroleum refining, and gasoline combustion for gasoline. For corn-based ethanol, the key factors in determining energy and emissions impacts include energy and chemical usage intensity of corn farming, energy intensity of the ethanol plant, and the method used to estimate energy and emissions credits for co-products of corn ethanol. The key factors in determining the impacts of cellulosic ethanol are energy and chemical usage intensity of biomass farming, ethanol yield per dry ton of biomass, and electricity credits in cellulosic ethanol plants. The results of our fuel-cycle analysis for fuel ethanol are listed below. Note that, in the first half of this summary, the reductions cited are per-vehicle-mile traveled using the specified ethanol/gasoline blend instead of conventional (not reformulated) gasoline. The second half of the summary presents estimated changes per gallon of ethanol used in ethanol blends. GHG emissions are global warming potential (GWP)-weighted, carbon dioxide (CO2)-equivalent emissions of CO2, methane (CH4), and nitrous oxide (N2O)

Fuel morphology effects on fission product release

International Nuclear Information System (INIS)

Osetek, D.J.; Hartwell, J.K.; Cronenberg, A.W.

1986-01-01

Results are presented of fission product release behavior observed during four severe fuel damage tests on bundles of UO 2 fuel rods. Transient temperatures up to fuel melting were obtained in the tests that included both rapid and slow cooldown, low and high (36 GWd/t) burnup fuel and the addition of Ag-In-Cd control rods. Release fractions of major fission product species and release rates of noble gas species are reported. Significant differences in release behavior are discussed between heatup and cooldown periods, low and high burnup fuel and long- and short-lived fission products. Explanations for the observed differences are offered that relate fuel morphology changes to the releases

Numerical analysis on effect of aspect ratio of planar solid oxide fuel cell fueled with decomposed ammonia

Science.gov (United States)

Tan, Wee Choon; Iwai, Hiroshi; Kishimoto, Masashi; Brus, Grzegorz; Szmyd, Janusz S.; Yoshida, Hideo

2018-04-01

Planar solid oxide fuel cells (SOFCs) with decomposed ammonia are numerically studied to investigate the effect of the cell aspect ratio. The ammonia decomposer is assumed to be located next to the SOFCs, and the heat required for the endothermic decomposition reaction is supplied by the thermal radiation from the SOFCs. Cells with aspect ratios (ratios of the streamwise length to the spanwise width) between 0.130 and 7.68 are provided with the reactants at a constant mass flow rate. A parametric study is conducted by varying the cell temperature and fuel utility factor to investigate their effects on the cell performance in terms of the voltage efficiency. The effect of the heat supply to the ammonia decomposer is also studied. The developed model shows good agreement, in terms of the current-voltage curve, with the experimental data obtained from a short stack without parameter tuning. The simulation study reveals that the cell with the highest aspect ratio achieves the highest performance under furnace operation. On the other hand, the 0.750 aspect ratio cell with the highest voltage efficiency of 0.67 is capable of thermally sustaining the ammonia decomposers at a fuel utility of 0.80 using the thermal radiation from both sidewalls.

Measuring the effect of fuel treatments on forest carbon using landscape risk analysis

Science.gov (United States)

A.A. Ager; M.A. Finney; A. McMahan; J. Carthcart

2010-01-01

Wildfire simulation modelling was used to examine whether fuel reduction treatments can potentially reduce future wildfire emissions and provide carbon benefits. In contrast to previous reports, the current study modelled landscape scale effects of fuel treatments on fire spread and intensity, and used a probabilistic framework to quantify wildfire effects on carbon...

Effects of Oxygen Content of Fuels on Combustion and Emissions of Diesel Engines

Directory of Open Access Journals (Sweden)

Haiwen Song

2016-01-01

Full Text Available Effects of oxygen content of fuels on combustion characteristics and emissions were investigated on both an optical single cylinder direct injection (DI diesel engine and a multi-cylinder engine. Three fuels were derived from conventional diesel fuel (Finnish City diesel summer grade by blending Rapeseed Methyl Ester (RME or Diglyme and Butyl-Diglyme of different quantities to make their oxygen content 3%, 3% and 9%, respectively. The experimental results with three tested fuels show that the fuel spray development was not affected apparently by the oxygenating. Compared with the base fuel, the ignition delay to pilot injection was shortened by 0%, 11% and 19% for three oxygenated fuels, respectively. The ignition delay to main injection was shortened by 10%, 19% and 38%, respectively. With regard to emissions, the smoke level was reduced by 24% to 90%, depending on fuel properties and engine running conditions. The penalties of increased NOx emissions and fuel consumption were up to 19% and 24%, respectively.

Effect of reactor chemistry and operating variables on fuel cladding corrosion in PWRs

International Nuclear Information System (INIS)

Park, Moon Ghu; Lee, Sang Hee

1997-01-01

As the nuclear industry extends the fuel cycle length, waterside corrosion of zircaloy cladding has become a limiting factor in PWR fuel design. Many plant chemistry factors such as, higher lithium/boron concentration in the primary coolant can influence the corrosion behavior of zircaloy cladding. The chemistry effect can be amplified in higher duty fuel, particularlywhen surface boiling occurs. Local boiling can result in increased crud deposition on fuel cladding which may induce axial power offset anomalies (AOA), recently reported in several PWR units. In this study, the effect of reactor chemistry and operating variables on Zircaloy cladding corrosion is investigated and simulation studies are performed to evaluate the optimal primary chemistry condition for extended cycle operation. (author). 8 refs., 3 tabs., 16 figs

Assessment of effective thermal conductivity in U–Mo metallic fuels with distributed gas bubbles

Energy Technology Data Exchange (ETDEWEB)

Hu, Shenyang; Casella, Andrew M.; Lavender, Curt A.; Senor, David J.; Burkes, Douglas E.

2015-07-15

This work presents a numerical method to assess the relative impact of various microstructural features including grain sizes, nanometer scale intragranular gas bubbles, and larger intergranular gas bubbles in irradiated U–Mo metallic fuels on the effective thermal conductivity. A phase-field model was employed to construct a three-dimensional polycrystalline U–Mo fuel alloy with a given crystal morphology and gas bubble microstructures. An effective thermal conductivity “concept” was taken to capture the effect of polycrystalline structures and gas bubble microstructures with significant size differences on the thermal conductivity. The thermal conductivity of inhomogeneous materials was calculated by solving the heat transport equation. The obtained results are in reasonably good agreement with experimental measurements made on irradiated U–Mo fuel samples containing similar microstructural features. The developed method can be used to predict the thermal conductivity degradation in operating nuclear fuels if the evolution of microstructures is known during operation of the fuel.

Fuel effect on solution combustion synthesis of Co(Cr,Al)2O4 pigments

International Nuclear Information System (INIS)

Gilabert, J.; Palacios, M.D.; Sanz, V.; Mestre, S.

2017-01-01

The fuel effect on the synthesis of a ceramic pigment with a composition CoCr2−2ΨAl2ΨO4 (0≤Ψ≤1) by means of solution combustion synthesis process (SCS) has been studied. Three different fuels were selected to carry out the synthesis (urea, glycine and hexamethylentetramine (HMT)). Highly foamy pigments with very low density were obtained. Fd-3m spinel-type structure was obtained in all the experiments. Nevertheless, crystallinity and crystallite size of the spinels show significant differences with composition and fuel. The use of glycine along with the chromium-richest composition favours ion rearrangement to obtain the most ordered structure. Lattice parameter does not seem to be affected by fuel, although it evolves with Ψ according to Vegard's law. Colouring power in a transparent glaze shows important variations with composition. On the other hand, fuel effect presents a rather low influence since practically the same shades are obtained. However, it exerts certain effect on luminosity (L*). [es

Climate consequences of low-carbon fuels: The United States Renewable Fuel Standard

International Nuclear Information System (INIS)

Hill, Jason; Tajibaeva, Liaila; Polasky, Stephen

2016-01-01

A common strategy for reducing greenhouse gas (GHG) emissions from energy use is to increase the supply of low-carbon alternatives. However, increasing supply tends to lower energy prices, which encourages additional fuel consumption. This “fuel market rebound effect” can undermine climate change mitigation strategies, even to the point where efforts to reduce GHG emissions by increasing the supply of low-carbon fuels may actually result in increased GHG emissions. Here, we explore how policies that encourage the production of low-carbon fuels may result in increased GHG emissions because the resulting increase in energy use overwhelms the benefits of reduced carbon intensity. We describe how climate change mitigation strategies should follow a simple rule: a low-carbon fuel with a carbon intensity of X% that of a fossil fuel must displace at least X% of that fossil fuel to reduce overall GHG emissions. We apply this rule to the United States Renewable Fuel Standard (RFS2). We show that absent consideration of the fuel market rebound effect, RFS2 appears to reduce GHG emissions, but once the fuel market rebound effect is factored in, RFS2 actually increases GHG emissions when all fuel GHG intensity targets are met. - Highlights: • Low-carbon fuels partially displace petroleum via fuel market rebound effect. • Synthesis of recent analyses shows incomplete petroleum displacement by biofuels. • Fuel market rebound effect can reduce or reverse climate benefit of low-carbon fuels. • Fossil fuel displacement must exceed relative carbon footprint of a low-carbon fuel. • The Renewable Fuel Standard increases greenhouse gas emissions when mandate is met.

Effect of Coal Contaminants on Solid Oxide Fuel System Performance and Service Life

Energy Technology Data Exchange (ETDEWEB)

Gopala Krishnan; P. Jayaweera; J. Bao; J. Perez; K. H. Lau; M. Hornbostel; A. Sanjurjo; J. R. Albritton; R. P. Gupta

2008-09-30

The U.S. Department of Energy's SECA program envisions the development of high-efficiency, low-emission, CO{sub 2} sequestration-ready, and fuel-flexible technology to produce electricity from fossil fuels. One such technology is the integrated gasification-solid oxide fuel cell (SOFC) that produces electricity from the gas stream of a coal gasifier. SOFCs have high fuel-to-electricity conversion efficiency, environmental compatibility (low NO{sub x} production), and modularity. Naturally occurring coal has many impurities and some of these impurities end in the fuel gas stream either as a vapor or in the form of fine particulate matter. Establishing the tolerance limits of SOFCs for contaminants in the coal-derived gas will allow proper design of the fuel feed system that will not catastrophically damage the SOFC or allow long-term cumulative degradation. The anodes of Ni-cermet-based SOFCs are vulnerable to degradation in the presence of contaminants that are expected to be present in a coal-derived fuel gas stream. Whereas the effects of some contaminants such as H{sub 2}S, NH{sub 3} and HCl have been studied, the effects of other contaminants such as As, P, and Hg have not been ascertained. The primary objective of this study was to determine the sensitivity of the performance of solid oxide fuel cells to trace level contaminants present in a coal-derived gas stream in the temperature range 700 to 900 C. The results were used to assess catastrophic damage risk and long-term cumulative effects of the trace contaminants on the lifetime expectancy of SOFC systems fed with coal-derived gas streams.

Theoretical Investigation For The Effect of Fuel Quality on Gas Turbine Power Plants

Science.gov (United States)

AbdulRazzak khudair, Omar; Alwan Abass, Khetam; Saadi Abed, Noor; Hussain Ali, Khalid; AbdulAziz, Saad; Chlaib Shaboot, Ali

2018-05-01

Gas turbine engine power generation is declined dramatically because of the reduction in thermodynamic parameters as a work of turbine, compressor ratio, compressor work, and air mass flow rate and fuel consumption. There are two main objectives of this work, the first is related with the effect of fuel kinds and their quality on the operation of fuel flow divider and its performance specifically gear pump displacement and fuel flow rate to the combustion chambers of gas power plant. AL-DORA gas turbine power plant 35MW was chosen to predict these effects on its performance MATLAB Software program is used to perform thermodynamic calculations. Fuel distribution stage before the process of combustion and as a result of the kind and its quality, chemical reaction will occur between the fuel and the parts of the gear system of each pump of the flow divider, which causes the erosion of the internal pump wall and the teeth of the gear system, thus hampering the pump operation in terms of fuel discharge. The discharge of fuel form the eight external gates of flow divider is decreased and varied when going to the combustion chambers, so that, flow divider does not give reliable mass flow rate due to absence of accurate pressure in each of eight exit pipes. The second objective deals with the stage of fuel combustion process inside the combustion chamber. A comparative study based upon performance parameters, such as specific fuel consumption for gas and gasoil and power generation. Fuel poor quality causes incomplete combustion and increased its consumption, so that combustion products are interacted with the surface of the turbine blades, causing the erosion and create surface roughness of the blade and disruption of gas flow. As a result of this situation, turbulence flow of these gases will increase causing the separation of gas boundary layers over the suction surface of the blade. Therefore the amount of extracted gas will decrease causing retreat work done by

Effects of ashes in solid fuels on fuel particle charging during combustion in an air stream

Energy Technology Data Exchange (ETDEWEB)

Zakharov, A.G.; Fialkov, B.S.; Mel' nichuk, A.Yu.; Khvan, L.A.

1982-09-01

Black coal from the Karaganda basin is mixed with sodium chloride and graphite. Coal characteristics are given in a table (density, ashes, content of silica, aluminium oxides, iron oxides, calcium oxides, potassium oxides and magnesium oxides). Effects of ash fluctuations on electric potential of fuel particles during combustion are analyzed. Analyses show that with increasing ash content electric potential of fuel particles decreases and reaches the minimum when ash content ranges from 70 to 80 %. Particles with electric potential are generated during chemical processes between carbon and oxygen when coal is burned in an air stream. (5 refs.) (In Russian)

Fossil fuel produced radioactivities and their effect on foodchains

Energy Technology Data Exchange (ETDEWEB)

Okamoto, K [New South Wales Univ., Kensington (Australia). Dept. of Applied Mathematics

1980-10-01

The environmental impact of radioactivities produced from fossil fuel burning is not necessarily small compared with that of nuclear energy. The effect of these radioactivities on the foodchain through seafoods is discussed.

Blending Biodiesel in Fishing Boat Fuels for Improved Fuel Characteristics

International Nuclear Information System (INIS)

Lin, Cherng-Yuan

2014-01-01

Biodiesel is a renewable, clean, alternative energy source with advantages, such as excellent lubricity, superior biodegradability, and high combustion efficiency. Biodiesel is considered for mixing with fishing boat fuels to adjust their fuel characteristics so that toxic pollutants and greenhouse-effect gas emissions from such shipping might be reduced. The effects of blending fishing boat fuels A and B with various weight proportions of biodiesel are experimentally investigated in this study. The results show that biodiesel blending can significantly improve the inferior fuel properties of both fishing boat fuels and particularly fuel B. The flash points of both of these fuels increases significantly with the addition of biodiesel and thus enhances the safety of transporting and storing these blended fuels. The flash point of fishing boat fuel B even increases by 16% if 25 wt.% biodiesel is blended. The blending of biodiesel with no sulfur content is found to be one of the most effective ways to reduce the high sulfur content of fishing boat fuel, resulting in a reduction in the emission of sulfur oxides. The addition of only 25 wt.% biodiesel decreased the sulfur content of the fishing boat fuel by 37%. The high kinematic viscosity of fishing boat fuel B was also observed to be reduced by 63% with the blending of just 25 wt.% biodiesel. However, biodiesel blending caused a slight decrease in heating value around 1–4.5%.

Blending Biodiesel in Fishing Boat Fuels for Improved Fuel Characteristics

Energy Technology Data Exchange (ETDEWEB)

Lin, Cherng-Yuan, E-mail: lin7108@ntou.edu.tw [Department of Marine Engineering, National Taiwan Ocean University, Keelung, Taiwan (China)

2014-02-24

Biodiesel is a renewable, clean, alternative energy source with advantages, such as excellent lubricity, superior biodegradability, and high combustion efficiency. Biodiesel is considered for mixing with fishing boat fuels to adjust their fuel characteristics so that toxic pollutants and greenhouse-effect gas emissions from such shipping might be reduced. The effects of blending fishing boat fuels A and B with various weight proportions of biodiesel are experimentally investigated in this study. The results show that biodiesel blending can significantly improve the inferior fuel properties of both fishing boat fuels and particularly fuel B. The flash points of both of these fuels increases significantly with the addition of biodiesel and thus enhances the safety of transporting and storing these blended fuels. The flash point of fishing boat fuel B even increases by 16% if 25 wt.% biodiesel is blended. The blending of biodiesel with no sulfur content is found to be one of the most effective ways to reduce the high sulfur content of fishing boat fuel, resulting in a reduction in the emission of sulfur oxides. The addition of only 25 wt.% biodiesel decreased the sulfur content of the fishing boat fuel by 37%. The high kinematic viscosity of fishing boat fuel B was also observed to be reduced by 63% with the blending of just 25 wt.% biodiesel. However, biodiesel blending caused a slight decrease in heating value around 1–4.5%.

Emergency fuels utilization guidebook. Alternative Fuels Utilization Program

Energy Technology Data Exchange (ETDEWEB)

1980-08-01

The basic concept of an emergency fuel is to safely and effectively use blends of specification fuels and hydrocarbon liquids which are free in the sense that they have been commandeered or volunteered from lower priority uses to provide critical transportation services for short-duration emergencies on the order of weeks, or perhaps months. A wide variety of liquid hydrocarbons not normally used as fuels for internal combustion engines have been categorized generically, including limited information on physical characteristics and chemical composition which might prove useful and instructive to fleet operators. Fuels covered are: gasoline and diesel fuel; alcohols; solvents; jet fuels; kerosene; heating oils; residual fuels; crude oils; vegetable oils; gaseous fuels.

Obesity-related health impacts of fuel excise taxation- an evidence review and cost-effectiveness study

Directory of Open Access Journals (Sweden)

V. Brown

2017-05-01

Full Text Available Abstract Background Reducing automobile dependence and improving rates of active transport may reduce the impact of obesogenic environments, thereby decreasing population prevalence of obesity and other diseases where physical inactivity is a risk factor. Increasing the relative cost of driving by an increase in fuel taxation may therefore be a promising public health intervention for obesity prevention. Methods A scoping review of the evidence for obesity or physical activity effect of changes in fuel price or taxation was undertaken. Potential health benefits of an increase in fuel excise taxation in Australia were quantified using Markov modelling to simulate obesity, injury and physical activity related health impacts of a fuel excise taxation intervention for the 2010 Australian population. Health adjusted life years (HALYs gained and healthcare cost savings from diseases averted were estimated. Incremental cost-effectiveness ratios (ICERs were reported and results were tested through sensitivity analysis. Results Limited evidence on the effect of policies such as fuel taxation on health-related behaviours currently exists. Only three studies were identified reporting associations between fuel price or taxation and obesity, whilst nine studies reported associations specifically with physical activity, walking or cycling. Estimates of the cross price elasticity of demand for public transport with respect to fuel price vary, with limited consensus within the literature on a probable range for the Australian context. Cost-effectiveness modelling of a AUD0.10 per litre increase in fuel excise taxation using a conservative estimate of cross price elasticity for public transport suggests that the intervention would be cost-effective from a limited societal perspective (237 HALYs gained, AUD2.6 M in healthcare cost savings, measured against a comparator of no additional increase in fuel excise. Under “best case” assumptions, the intervention

Effects of high density dispersion fuel loading on the kinetic parameters of a low enriched uranium fueled material test research reactor

Energy Technology Data Exchange (ETDEWEB)

Muhammad, Farhan [Department of Nuclear Engineering, Pakistan Institute of Engineering and Applied Sciences, P.O. Nilore, Islamabad 45650 (Pakistan)], E-mail: mfarhan_73@yahoo.co.uk; Majid, Asad [Department of Nuclear Engineering, Pakistan Institute of Engineering and Applied Sciences, P.O. Nilore, Islamabad 45650 (Pakistan)

2008-09-15

The effects of using high density low enriched uranium on the neutronic parameters of a material test research reactor were studied. For this purpose, the low density LEU fuel of an MTR was replaced with high density LEU fuels currently being developed under the RERTR program. Since the alloying elements have different cross-sections affecting the reactor in different ways, therefore fuels U-Mo (9 w/o) which contain the same elements in same ratio were selected for analysis. Simulations were carried out to calculate core excess reactivity, neutron flux spectrum, prompt neutron generation time, effective delayed neutron fraction and feedback coefficients including Doppler feedback coefficient, and reactivity coefficients for change of water density and temperature. Nuclear reactor analysis codes including WIMS-D4 and CITATION were employed to carry out these calculations. It is observed that the excess reactivity at the beginning of life does not increase as the uranium density of fuel. Both the prompt neutron generation time and the effective delayed neutron fraction decrease as the uranium density increases. The absolute value of Doppler feedback coefficient increases while the absolute values of reactivity coefficients for change of water density and temperature decrease.

Effects of high density dispersion fuel loading on the kinetic parameters of a low enriched uranium fueled material test research reactor

International Nuclear Information System (INIS)

Muhammad, Farhan; Majid, Asad

2008-01-01

The effects of using high density low enriched uranium on the neutronic parameters of a material test research reactor were studied. For this purpose, the low density LEU fuel of an MTR was replaced with high density LEU fuels currently being developed under the RERTR program. Since the alloying elements have different cross-sections affecting the reactor in different ways, therefore fuels U-Mo (9 w/o) which contain the same elements in same ratio were selected for analysis. Simulations were carried out to calculate core excess reactivity, neutron flux spectrum, prompt neutron generation time, effective delayed neutron fraction and feedback coefficients including Doppler feedback coefficient, and reactivity coefficients for change of water density and temperature. Nuclear reactor analysis codes including WIMS-D4 and CITATION were employed to carry out these calculations. It is observed that the excess reactivity at the beginning of life does not increase as the uranium density of fuel. Both the prompt neutron generation time and the effective delayed neutron fraction decrease as the uranium density increases. The absolute value of Doppler feedback coefficient increases while the absolute values of reactivity coefficients for change of water density and temperature decrease

Potential exposures and health effects from spent fuel transportation

International Nuclear Information System (INIS)

Sandquist, G.M.; Rogers, V.C.

1986-01-01

The radiation exposures and consequent health effects associated with normal operations and accidents during transportation of spent fuel have been analyzed and evaluated. This study was performed for the U.S. Department of Energy (DOE) as contributory data for response to specific public inquires regarding the Draft Environmental Assessments issued by DOE in 1984. Large quantities of spent fuel from power reactors will be shipped by truck and/or rail from the site of generation or temporary storage to nuclear waste repositories. This transportation activity has the potential for increasing radiation exposures and risks above normal background levels in the vicinity of the transportation route. For normal, accident-free transport of spent fuel, radiation exposures arise from both gamma and neutron sources within the spent fuel cask. U.S. regulations limit the radiation dose equivalent rate to 10 millirem per hour at any point 2 meters from the outer lateral surfaces of the transport vehicle. Computer program PATHRAE-T was developed and employed to determine the total, combined dose field. PATHRAE-T was used to estimate the maximum individual doses from rail cask accidents. The maximum individual exposure, primarily due to inhalation, is about 10 rem and occurs about 70 meters downwind. Ground deposited nuclides account for 99 percent of the population dose. The maximum population dose accident could result in about 22 latent health effects for the urban population. The same case rail cask accidents were also evaluated for a maximum water pathway contamination scenario. The nuclide contaminated plume was assumed to be transported over a large reservoir used for domestic and agricultural water. This accident could result in a 63,000 person-rem dose causing about 13 latent health effects in the absence of any natural and industrial processes for nuclide removal from the water

The Analysis of the Effect of Coolant Channel Width on Fuel Loading of the RSG-GAS Core

International Nuclear Information System (INIS)

Surbakti; Tukiran

2004-01-01

The RGS-GAS using uranium silicide fuel, plate type and 250 g U of loading is planned to increase the fuel loading to 300 g U even to 400 g U. The silicide fuel has advantages when increase the fuel loading in the same volume. Because of that case, it is necessary to analyze the effect of coolant channel width on fuel loading of the RSG-GAS core. Analyzing the effect the work which done is to generate cell and core calculation using WIMSD/4 and Batan-2DIFF codes. The WIMSD/4 code is used to generate cross section of core material and Batan-2DIFF is used to calculate the effective multiplication factor. The model that used in this calculation there are three kind of fuel loading namely, 250 g U, 300 g U and 400 g U. The coolant channel width is simulated from 1.75 mm to 2.55 mm. From that fuel loadings, it is analyzed which coolant channel width gave the best effective multiplication factor. From result of analysis showed that the best effective multiplication factor is on the coolant channel width of 2.55 mm for third of fuel loadings. (author)

Driving for fun? Comparing the effect of fuel prices on weekday and weekend fuel consumption

Energy Technology Data Exchange (ETDEWEB)

Frondel, Manuel; Vance, Colin [Rheinisch-Westfaelisches Institut fuer Wirtschaftsforschung (RWI), Hohenzollernstr. 1-3, D-45128 Essen (Germany)

2010-01-15

Focusing on individual motorists in car-owning households in Germany, this paper investigates the determinants of automobile travel, with the specific aim of quantifying the effects of fuel prices and person-level attributes on travel conducted over a five-day week and weekend. Our analysis is predicated on the notion that car use is an individual decision, albeit one that is dependent on intra-household allocation processes, thereby building on a growing body of literature that has identified the importance of socioeconomic factors such as employment status, gender, and the presence of children in determining both access to and use of the car. To capture this two-stage decision process, we employ the two-part model, which consists of probit and OLS estimators, and derive elasticity estimates that incorporate both the discrete and continuous choices pertaining to car use. With fuel price elasticity estimates ranging between - 0.45 and - 0.50, our results suggest raising prices via fuel taxes to be a promising energy conservation and climate protection measure. (author)

Driving for fun? Comparing the effect of fuel prices on weekday and weekend fuel consumption

International Nuclear Information System (INIS)

Frondel, Manuel; Vance, Colin

2010-01-01

Focusing on individual motorists in car-owning households in Germany, this paper investigates the determinants of automobile travel, with the specific aim of quantifying the effects of fuel prices and person-level attributes on travel conducted over a five-day week and weekend. Our analysis is predicated on the notion that car use is an individual decision, albeit one that is dependent on intra-household allocation processes, thereby building on a growing body of literature that has identified the importance of socioeconomic factors such as employment status, gender, and the presence of children in determining both access to and use of the car. To capture this two-stage decision process, we employ the two-part model, which consists of probit and OLS estimators, and derive elasticity estimates that incorporate both the discrete and continuous choices pertaining to car use. With fuel price elasticity estimates ranging between - 0.45 and - 0.50, our results suggest raising prices via fuel taxes to be a promising energy conservation and climate protection measure. (author)

Emissions and Fuel Consumption Modeling for Evaluating Environmental Effectiveness of ITS Strategies

Directory of Open Access Journals (Sweden)

Yuan-yuan Song

2013-01-01

Full Text Available Road transportation is a major fuel consumer and greenhouse gas emitter. Recently, the intelligent transportation systems (ITSs technologies, which can improve traffic flow and safety, have been developed to reduce the fuel consumption and vehicle emissions. Emission and fuel consumption estimation models play a key role in the evaluation of ITS technologies. Based on the influence analysis of driving parameters on vehicle emissions, this paper establishes a set of mesoscopic vehicle emission and fuel consumption models using the real-world vehicle operation and emission data. The results demonstrate that these models are more appropriate to evaluate the environmental effectiveness of ITS strategies with enough estimation accuracy.

Effects of fuel properties, temperature, and pressure on fuel reactivity, formation and destruction of nitrogen oxides, and release of alkalis

International Nuclear Information System (INIS)

Aho, M.

1998-01-01

This study assists in the development of advanced combustion technologies (PFBC, IGCC) with high efficiency of electricity production from solid fuels (η = 47 - 50%) and in minimizing emissions of nitrogen oxides in atmospheric and pressurised FB combustion. In addition to the work done within the LIEKKI 2 programme, research work has been carried out inside the Joule 2 programme of EU. The research work may be divided into three parts: (1) Study of N x O y formation and destruction, (2) Study of fuel reactivity at elevated pressures, and (3) Study on alkali release from different coals. Experimental work was carried out utilizing a novel pressurized entrained flow reactor (PEFR) completed in VTT Energy in the autumn 1992. The device was unique in the world between 1992 and 1995. The effects of fuel properties on the formation of N 2 O and NO at conditions typical to FB combustion were studied for a large number of fuels including different coals, coal-derived char, peat, and bark. This work started before 1993 and was completed in 1995. FTIR technology was utilized for on-line gas analysis of N 2 O, NO, and NO 2 . The ratio fuel-O/fuel-N was found to be the most important fuel factor determining the formation of N 2 O and NO from volatile fuel-N. Only a small part of N 2 O is formed from char-N. The effect of pressure (0.2 - 2.0 MPa) on the formation of N 2 O, NO, and NO 2 , and destruction of NO with ammonia (Thermal DeNO x , experiments at 0.2, 0.5, and 1.5 MPa) and urea (NO x Out, experiments at 0.5 MPa) were studied in cooperation with Aabo Akademi University (AaAU). VTT performed the experimental work and AaAU the kinetic modelling. A part of these results are presented in the report by AaAU. Increase of pressure decreases NO formation and increases NO 2 formation. The behaviour of N 2 O is more complex. Both destruction processes for NO seem to operate well at elevated pressure, although clear effects of pressure on the temperature window of Thermal DeNO x

Study and simulation of the rim effect in rep fuel rods

International Nuclear Information System (INIS)

Hermitte, B.

1996-01-01

The RIM effect has been discovered fifteen years ago during the examination of first irradiated rods at more than 45 gWJ/TU in experimental reactors. The rods observation revealed a continuously degradation of the granular structure in the pellet skin, jointly to the porosity increase in this area. This study proposes a RIM formation and development mechanism for high combustion level. The first part presents the simulation of the fission gases in the fuel fraction concerned by the RIM. In the proposed model the gas bubbles increase is bound to the volume fraction of restructured fuel. This model allows the determination of the pores volume fraction in the fuel, the average size of these pores and the volume distribution of the fission gases between the bubbles and the fuel matrix. (A.L.B.)

The fuel string relocation effect - why the Bruce reactors were derated

Energy Technology Data Exchange (ETDEWEB)

Gold, M; Farooqui, M Z; Adebiyi, A S; Chu, R Y; Le, N T; Oliva, A F [Ontario Hydro, Toronto, ON (Canada); Balog, G; Qu, T; DeBuda, P G [Ontario Hydro, Tiverton, ON (Canada). Bruce Nuclear Generating Station-A

1996-12-31

In the CANDU Safety Analysis process, a series of design basis accidents are chosen and analyzed to confirm safety system effectiveness. Of all the postulated accidents, the Large Break Loss of Coolant Accident (LBLOCA) - a postulated break in the Heat Transport System piping near a component that services a large number of fuel channels - sets the most demanding requirements on the speed and reactivity depth of the shutdown system devices - shutoff rods and liquid poison injection. While the event is extremely improbable, it is reanalyzed periodically and its consequences examined to ensure continued shutdown system effectiveness. In March 1993, an additional effect was identified: if the break occurred in the piping on the inlet side of the core, this would cause sudden movement of the fuel bundles (so-called fuel string relocation) in a large number of channels. In Ontario Hydro`s Bruce NGS A, Bruce NGS B and Darlington reactors, each channel is fuelled against the flow. In this situation, the relocation of the fuel string results in a sudden positive reactivity increase. This reactivity increase is in addition to the reactivity due to the core coolant voiding. The combined reactivity effect could lead to power pulses much higher than those that would arise due to coolant voiding alone. To maintain safety margins in the event of such a postulated accident, the eight Bruce NGS A and Bruce NGS B units were initially derated to 60 percent power within 2 days of the identification and confirmation of this effect. This paper: describes the fuel string relocation phenomenon in detail; explains why the consequences differ at the various Ontario Hydro reactors; outlines the actions taken with respect to each of the Ontario Hydro reactors in the months following March 1993; describes the design solutions implemented to mitigate the problem and return the Bruce reactors to higher powers. 6 refs., 1 tab., 6 figs.

Fire suppression and fuels treatment effects on mixed-conifer carbon stocks and emissions

Science.gov (United States)

M. North; M Hurteau; J Innes

2009-01-01

Depending on management, forests can be an important sink or source of carbon that if released as CO2 could contribute to global warming. Many forests in the western United States are being treated to reduce fuels, yet the effects of these treatments on forest carbon are not well understood. We compared the immediate effects of fuels treatments on carbon stocks and...

Chronic fuel oil toxicity in American mink (Mustela vison): systemic and hematological effects of ingestion of a low-concentration of bunker C fuel oil

International Nuclear Information System (INIS)

Schwartz, Julie A.; Aldridge, Brian M.; Lasley, Bill L.; Snyder, Paul W.; Stott, Jeff L.; Mohr, F. Charles

2004-01-01

Petroleum oil enters the coastal marine environment through various sources; marine mammals such as sea otters that inhabit this environment may be exposed to low concentrations of petroleum hydrocarbons through ingestion of contaminated prey. The inability to perform controlled studies in free-ranging animals hinders investigations of the effects of chronic petroleum oil exposure on sea otter morbidity and mortality, necessitating the development of a reliable laboratory model. We examined the effects of oral exposure to 500 ppm bunker C fuel oil over 113-118 days on American mink, a species phylogenetically related to the sea otter. Hematological parameters and organs were examined for fuel oil-associated changes. Hepatic cytochrome P4501A1 mRNA expression and fecal cortisol concentrations were also measured. Ingestion of fuel oil was associated with a decrease in erythrocyte count, hemoglobin concentration (Hgb), hematocrit (HCT), and an increase in mean corpuscular volume (MCV). Total leukocytes were elevated in the fuel oil group from increases in neutrophils, lymphocytes, and monocytes. Significant interactions between fuel oil and antigen challenge were found for erythrocyte parameters, monocyte and lymphocyte counts. Liver and adrenal weights were increased although mesenteric lymph node weights were decreased in the fuel oil group. Hepatic cytochrome P4501A1 mRNA was elevated in the fuel oil group. Fecal cortisol concentration did not vary between the two groups. Our findings show that fuel oil exposure alters circulating leukocyte numbers, erythrocyte homeostasis, hepatic metabolism and adrenal physiology and establish a framework to use mink as a model for sea otters in studying the systemic effects of marine contaminants

Soil moisture effects during bioventing in fuel-contaminated arid soils

International Nuclear Information System (INIS)

Zwick, T.C.; Leeson, A.; Hinchee, R.E.; Hoeppel, R.E.; Bowling, L.

1995-01-01

This study evaluated the effects of soil moisture addition on microbial activity during bioventing of dry, sandy soils at the Marine Corps Air Ground Combat Center (MCAGCC), Twentynine Palms, California. Soils at the site have been contaminated to a depth of approximately 80 ft (24 m) with gasoline, JP-5 jet fuel, and diesel fuel. Based on the low soil moisture measured at the site (2 to 3% by weight), it was determined that soil moisture may be limiting biodegradation. To evaluate the effect that moisture addition had on microbial activity under field conditions, a subsurface drip irrigation system was installed above the fuel hydrocarbon plume. Irrigation water was obtained from two monitoring wells on the site, where groundwater was approximately 192 ft (59 m) below ground surface. Advancement of the wetting front was monitored. In situ respiration rates increased significantly after moisture addition. The results of this study provide evidence for the potential applicability of moisture addition in conjunction with bioventing for site remediation in arid environments. Further work is planned to investigate optimization of moisture addition

Fuel cycles with high fuel burn-up: analysis of reactivity coefficients

International Nuclear Information System (INIS)

Kryuchkov, E.F.; Shmelev, A.N.; Ternovykh, M.J.; Tikhomirov, G.V.; Jinhong, L.; Saito, M.

2003-01-01

Fuel cycles of light-water reactors (LWR) with high fuel burn-up (above 100 MWd/kg), as a rule, involve large amounts of fissionable materials. It leads to forming the neutron spectrum harder than that in traditional LWR. Change of neutron spectrum and significant amount of non-traditional isotopes (for example, 237 Np, 238 Pu, 231 Pa, 232 U) in such fuel compositions can alter substantially reactivity coefficients as compared with traditional uranium-based fuel. The present work addresses the fuel cycles with high fuel burn-up which are based on Th-Pa-U and U-Np-Pu fuel compositions. Numerical analyses are carried out to determine effective neutron multiplication factor and void reactivity coefficient (VRC) for different values of fuel burn-up and different lattice parameters. The algorithm is proposed for analysis of isotopes contribution to these coefficients. Various ways are considered to upgrade safety of nuclear fuel cycles with high fuel burn-up. So, the results obtained in this study have demonstrated that: -1) Non-traditional fuel compositions developed for achievement of high fuel burn-up in LWR can possess positive values of reactivity coefficients that is unacceptable from the reactor operation safety point of view; -2) The lattice pitch of traditional LWR is not optimal for non-traditional fuel compositions, the increased value of the lattice pitch leads to larger value of initial reactivity margin and provides negative VRC within sufficiently broad range of coolant density; -3) Fuel burn-up has an insignificant effect on VRC dependence on coolant density, so, the measures undertaken to suppress positive VRC of fresh fuel will be effective for partially burnt-up fuel compositions also and; -4) Increase of LWR core height and introduction of additional moderators into the fuel lattice can be used as the ways to reach negative VRC values for full range of possible coolant density variations

Fission-induced recrystallization effect on intergranular bubble-driven swelling in U-Mo fuel

Energy Technology Data Exchange (ETDEWEB)

Liang, Linyun; Mei, Zhi-Gang; Yacout, Abdellatif M.

2017-10-01

We have developed a mesoscale phase-field model for studying the effect of recrystallization on the gas-bubble-driven swelling in irradiated U-Mo alloy fuel. The model can simulate the microstructural evolution of the intergranular gas bubbles on the grain boundaries as well as the recrystallization process. Our simulation results show that the intergranular gas-bubble-induced fuel swelling exhibits two stages: slow swelling kinetics before recrystallization and rapid swelling kinetics with recrystallization. We observe that the recrystallization can significantly expedite the formation and growth of gas bubbles at high fission densities. The reason is that the recrystallization process increases the nucleation probability of gas bubbles and reduces the diffusion time of fission gases from grain interior to grain boundaries by increasing the grain boundary area and decreasing the diffusion distance. The simulated gas bubble shape, size distribution, and density on the grain boundaries are consistent with experimental measurements. We investigate the effect of the recrystallization on the gas-bubble-driven fuel swelling in UMo through varying the initial grain size and grain aspect ratio. We conclude that the initial microstructure of fuel, such as grain size and grain aspect ratio, can be used to effectively control the recrystallization and therefore reduce the swelling in U-Mo fuel.

Theory of precipitation effects on dead cylindrical fuels

Science.gov (United States)

Michael A. Fosberg

1972-01-01

Numerical and analytical solutions of the Fickian diffusion equation were used to determine the effects of precipitation on dead cylindrical forest fuels. The analytical solution provided a physical framework. The numerical solutions were then used to refine the analytical solution through a similarity argument. The theoretical solutions predicted realistic rates of...

Water reactor fuel element fabrication, with special emphasis on its effects on fuel performance

International Nuclear Information System (INIS)

1979-01-01

Full text: The performance of nuclear fuel has improved over the years and is now a minor cause of outages and of power limitations in nuclear power plants. On the other hand, an increasing number of countries are in the process of developing or implementing their own capability for manufacturing fuel elements. In this context, the IAEA International Working Group on Water Reactor Fuel Performance and Technology (IWGFPT) advised that a symposium be organized devoted to the relationship between fuel fabrication and performance The Czechoslovak Atomic Energy Commission agreed to co-operate in the organization of this symposium and to host it in Prague. Those factors which influence fuel fabrication requirements are now well ascertained: as little reactor primary circuit contamination as possible, the tendency to increased burnups, reactor manoeuverability to match power grid demands, the desirability of an autonomous fabrication capability. It is the general experience of fuel element suppliers that fuel quality and performance has increased over the years, the importance of quality assurance and process monitoring has been decisive in this respect The ever increasing mass-production aspect of nuclear fuel leads to some processing steps being revised and alternatives being developed. The relation between fabrication processes and fuel performance characteristics, although generally well perceived, are still the subject of a large amount of experiment and assessment in most countries, both industrial and developing This evidence is most encouraging; it means indeed that nuclear power, which is already amongst the cheapest and safest sources of energy, will continue to be improved. The performance of Zircaloy fuel cladding - presently the material used in most water reactors - is under particular consideration. Better understanding of this quite recent alloy will pave the way for broader fuel utilization limits in the future. The panel discussion, which noted some

Biodiesel production from various feedstocks and their effects on the fuel properties.

Science.gov (United States)

Canakci, M; Sanli, H

2008-05-01

Biodiesel, which is a new, renewable and biological origin alternative diesel fuel, has been receiving more attention all over the world due to the energy needs and environmental consciousness. Biodiesel is usually produced from food-grade vegetable oils using transesterification process. Using food-grade vegetable oils is not economically feasible since they are more expensive than diesel fuel. Therefore, it is said that the main obstacle for commercialization of biodiesel is its high cost. Waste cooking oils, restaurant greases, soapstocks and animal fats are potential feedstocks for biodiesel production to lower the cost of biodiesel. However, to produce fuel-grade biodiesel, the characteristics of feedstock are very important during the initial research and production stage since the fuel properties mainly depend on the feedstock properties. This review paper presents both biodiesel productions from various feedstocks and their effects on the fuel properties.

The effect of the fuel rod friction force to the fuel assembly lateral mechanical characteristics

International Nuclear Information System (INIS)

Ha, Dong Geun; Jeon, Sang Youn; Suh, Jung Min

2012-01-01

The Fuel Assembly (FA) for light water reactor consists of hundreds of fuel rods, guide tubes, spacer grids, top/bottom nozzles. The guide tubes transmit vertical loads between the top and bottom nozzles, position the fuel rod support grids vertically, react the loads from the fuel rods that are applied to the grids, and provide some of the lateral load capability for the overall fuel assembly. The guide tubes are the structural members of the skeleton assembly. And the spacer grids maintain the fuel rod array by providing positive lateral restraint to the fuel rod but only frictional restraint in the axial direction. Figure 1 shows the outline of skeleton, FA and the location of guide tubes in the view of cross section. 17x17 FA has 24 guide tubes and one instrumentation tube. When the FA is in reactor, the lateral stiffness is one of very important factors from the view point of in reactor integrity of fuel assembly such as guarantee of the cool able geometry, the control rod insertion etc. The lateral stiffness of FA is mainly determined by skeleton lateral stiffness. And the fuel rods loaded in the spacer grids reinforce the FA lateral stiffness. Generally, fuel rods and spacer grids create the nonlinear friction force between fuel rod tube and grid spring/dimple against external lateral force of FA. Thus, it is necessary to study the contribution of the fuel rods friction force to the FA lateral stiffness. So, this paper is to show how much amount of the fuel rod grid interaction contributes to the FA lateral stiffness based on the test results

Effect of W/O Emulsion Fuel Properties on Spray Combustion

Science.gov (United States)

Ida, Tamio; Fuchihata, Manabu; Takeda, Shuuco

This study proposes a realizable technology for an emulsion combustion method that can reduce environmental loading. This paper discusses the effect on spray combustion for W/O emulsion fuel properties with an added agent, and the ratio between water and emulsifier added to a liquid fuel. The addition of water or emulsifier to a liquid fuel affected the spray combustion by causing micro-explosions in the flame due to geometric changes in the sprayed flame and changes to the temperature distribution. Experimental results revealed that the flame length shortened by almost 40% upon the addition of the water. Furthermore, it was found that water was effective in enhancing combustion due to its promoting micro-explosions. Results also showed that when the emulsifier was added to the spray flame, the additive burned in the flame's wake, producing a bright red flame. The flame length was observed to be long as a result. The micro-explosion phenomenon, caused by emulsifier dosage differences, was observed using time-dependent images at a generated frequency and an explosion scale with a high-speed photography method. Results indicated that the micro-explosion phenomenon in the W/O emulsion combustion method effectively promoted the combustion reaction and suppressed soot formation.

Experimental Measurement and Numerical Modeling of the Effective Thermal Conductivity of TRISO Fuel Compacts

International Nuclear Information System (INIS)

Folsom, Charles

2015-01-01

Accurate modeling capability of thermal conductivity of tristructural-isotropic (TRISO) fuel compacts is important to fuel performance modeling and safety of Generation IV reactors. To date, the effective thermal conductivity (ETC) of tristructural-isotropic (TRISO) fuel compacts has not been measured directly. The composite fuel is a complicated structure comprised of layered particles in a graphite matrix. In this work, finite element modeling is used to validate an analytic ETC model for application to the composite fuel material for particle-volume fractions up to 40%. The effect of each individual layer of a TRISO particle is analyzed showing that the overall ETC of the compact is most sensitive to the outer layer constituent. In conjunction with the modeling results, the thermal conductivity of matrix-graphite compacts and the ETC of surrogate TRISO fuel compacts have been successfully measured using a previously developed measurement system. The ETC of the surrogate fuel compacts varies between 50-30 W m -1 K -1 over a temperature range of 50-600°C. As a result of the numerical modeling and experimental measurements of the fuel compacts, a new model and approach for analyzing the effect of compact constituent materials on ETC is proposed that can estimate the fuel compact ETC with approximately 15-20% more accuracy than the old method. Using the ETC model with measured thermal conductivity of the graphite matrix-only material indicate that, in the composite form, the matrix material has a much greater thermal conductivity, which is attributed to the high anisotropy of graphite thermal conductivity. Therefore, simpler measurements of individual TRISO compact constituents combined with an analytic ETC model, will not provide accurate predictions of overall ETC of the compacts emphasizing the need for measurements of composite, surrogate compacts.

Compositional Effects of Gasoline Fuels on Combustion, Performance and Emissions in Engine

KAUST Repository

Ahmed, Ahfaz

2016-10-17

Commercial gasoline fuels are complex mixtures of numerous hydrocarbons. Their composition differs significantly owing to several factors, source of crude oil being one of them. Because of such inconsistency in composition, there are multiple gasoline fuel compositions with similar octane ratings. It is of interest to comparatively study such fuels with similar octane ratings and different composition, and thus dissimilar physical and chemical properties. Such an investigation is required to interpret differences in combustion behavior of gasoline fuels that show similar knock characteristics in a cooperative fuel research (CFR) engine, but may behave differently in direct injection spark ignition (DISI) engines or any other engine combustion modes. Two FACE (Fuels for Advanced Combustion Engines) gasolines, FACE F and FACE G with similar Research and Motor Octane Numbers but dissimilar physical properties were studied in a DISI engine under two sets of experimental conditions; the first set involved early fuel injection to allow sufficient time for fuel-air mixing hence permitting operation similar to homogenous DISI engines, while the second set consists of advance of spark timings to attain MBT (maximum brake torque) settings. These experimental conditions are repeated across different load points to observe the effect of increasing temperature and pressure on combustion and emission parameters. The differences in various engine-out parameters are discussed and interpreted in terms of physical and thermodynamic properties of the fuels.

Ecological effects of fuel cycle activities

Energy Technology Data Exchange (ETDEWEB)

Barnthouse, L; Cada, G; Kroodsma, R; Shriner, D; Tolbert, V; Turner, R

1994-07-01

The purpose of this paper is to summarize the approach used to characterize ecological impacts of the coal fuel cycle. The same approach is used for many of the impacts in other fuel cycles as well. The principal analytical approach being used in the study is an accounting framework - that is, a series of matrices that map each phase of the fuel cycle to a suite of possible. emissions, each emission to a suite of impact categories, and each impact category to an external cost. This paper summarizes the ecological impacts of all phases of the coal fuel cycle, defines the ecological impact categories used in the study's 'accounting framework', and discusses alternative approaches to quantification. Externalities associated with CO{sub 2}-induced global climate change are beyond the scope of this paper and are not discussed.

Ecological effects of fuel cycle activities

International Nuclear Information System (INIS)

Barnthouse, L.; Cada, G.; Kroodsma, R.; Shriner, D.; Tolbert, V.; Turner, R.

1994-01-01

The purpose of this paper is to summarize the approach used to characterize ecological impacts of the coal fuel cycle. The same approach is used for many of the impacts in other fuel cycles as well. The principal analytical approach being used in the study is an accounting framework - that is, a series of matrices that map each phase of the fuel cycle to a suite of possible. emissions, each emission to a suite of impact categories, and each impact category to an external cost. This paper summarizes the ecological impacts of all phases of the coal fuel cycle, defines the ecological impact categories used in the study's 'accounting framework', and discusses alternative approaches to quantification. Externalities associated with CO 2 -induced global climate change are beyond the scope of this paper and are not discussed

The determinants of fuel use in the trucking industry – volume, size and the rebound effect

DEFF Research Database (Denmark)

Mulalic, Ismir

2011-01-01

We analyse the determinants of trucking firm fuel use. We develop a simple model to show that trucking firm fuel use depends, in addition to the fuel price and the traffic volume, also on the output of the trucking firm’s production process (the movement of cargo) measured in tonkilometres...... these elasticities using a simultaneous-equation model based on aggregate time-series data for Denmark for 1980-2007. Our best estimates of the short run and the long run rebound effects for road freight transportation are 19% and 28%, respectively. We also find that an increase in the fuel price surprisingly has...... a small but significant negative effect on the fuel efficiency (measured here as vehicle kilometres travelled (VKT) per litre of consumed fuel), i.e. a 1% increase in the fuel price decreases the fuel efficiency by 0.13% in the long run. However, less distance has to be driven for the same payload. An 1...

Effect of time-varying humidity on the performance of a polymer electrolyte membrane fuel cells

Energy Technology Data Exchange (ETDEWEB)

Noorani, Shamsuddin [Department of Mechanical Engineering, University of Michigan-Dearborn (United States); Shamim, Tariq [Mechanical Engineering, Masdar Institute of Science and Technology (United Arab Emirates)], E-mail: tshamim@masdar.ac.ae

2011-07-01

In the energy sector, fuel cells constitute a promising solution for the future due to their energy-efficient and environment-friendly characteristics. However, the performance of fuel cells is very much affected by the humidification level of the reactants, particularly in hot regions. The aim of this paper is to develop a better understanding of the effect of driving conditions on the performance of fuel cells. A macroscopic single-fuel-cell-based, one dimensional, isothermal model was used on a polymer electrolyte membrane fuel cell to carry out a computational study of the impact of humidity conditions which vary over time. It was found that the variation of humidity has a significant effect on water distribution but a much lower impact on power and current densities. This paper provided useful information on fuel cells' performance under varying conditions which could be used to improve their design for mobile applications.

The Effect of Fuel Injector Nozzle Configuration on JP-8 Sprays at Diesel Engine Conditions

Science.gov (United States)

2014-10-01

The Effect of Fuel Injector Nozzle Configuration on JP-8 Sprays at Diesel Engine Conditions by Matthew Kurman, Luis Bravo, Chol-Bum Kweon...Fuel Injector Nozzle Configuration on JP-8 Sprays at Diesel Engine Conditions Matthew Kurman, Luis Bravo, and Chol-Bum Kweon Vehicle Technology...March 2014 4. TITLE AND SUBTITLE The Effect of Fuel Injector Nozzle Configuration on JP-8 Sprays at Diesel Engine Conditions 5a. CONTRACT NUMBER 5b

Experiments to investigate the effects of small changes in fuel stoichiometry on fission gas release

Energy Technology Data Exchange (ETDEWEB)

Copeland, P S; Smith, R C [Windscale Lab., AEA Technology, Seascale, Cumbria (United Kingdom)

1997-08-01

Fuel pin failure in-reactor leads to fission product and in the case of a PWR fuel debris release to the coolant. For economic reasons immediate shutdown and discharge of failed fuel needs to be avoided but this needs to be counter-balanced against the increasing dose to operators. PWR practice is to continue running wit failed rods, monitoring coolant activity, and only shutting down the reactor and discharging the fuel when circuit activity levels become unacceptable. The rate of fission product release under failed fuel conditions is of key importance and considerable effort has been directed towards establishing the dependency of release on temperature, heating rate, burn-up, and also the extent of fuel oxidation. As a precursor to a possible wider investigation of this area, a small programme was mounted during 1992/1993 to confirm whether small changes in the oxidation state of the fuel, for example those caused by minor cladding defects, would significantly effect fuel behaviour during postulated design basis faults. The objective of the programme was to determine the effects of small departures from stoichiometric fuel composition on fission gas release, and to compare the results with the current methodology for calculating releases under fault conditions. A total of eight experiments was performed. Two were intended as baseline tests to provide a reference with which to compare the effect of oxidation state influenced behaviour with that of thermal effects. It was found that small changes in stoichiometry of {sup {approx}}1 x 10{sup -6} had little or no effect on release but that changes of {sup {approx}} 1 x 10{sup -4} were observed to increase the diffusion coefficient, for {sup 85}Kr, by up to an order of magnitude and hence greatly increase the release rate. The stoichiometry of the sample used in these tests was, for convenience, adjusted using He/H{sub 2}/H{sub 2}O atmospheres. (Abstract Truncated)

The Effect of Uncertainties on the Operating Temperature of U-Mo/Al Dispersion Fuel

Energy Technology Data Exchange (ETDEWEB)

Sweidana, Faris B.; Mistarihia, Qusai M.; Ryu Ho Jin [KAIST, Daejeon (Korea, Republic of); Yim, Jeong Sik [KAERI, Daejeon (Korea, Republic of)

2016-05-15

In this study, uncertainty and combined uncertainty studies have been carried out to evaluate the uncertainty of the parameters affecting the operational temperature of U-Mo/Al fuel. The uncertainties related to the thermal conductivity of fuel meat, which consists of the effects of thermal diffusivity, density and specific heat capacity, the interaction layer (IL) that forms between the dispersed fuel and the matrix, fuel plate dimensions, heat flux, heat transfer coefficient and the outer cladding temperature were considered. As the development of low-enriched uranium (LEU) fuels has been pursued for research reactors to replace the use of highly-enriched uranium (HEU) for the improvement of proliferation resistance of fuels and fuel cycle, U-Mo particles dispersed in an Al matrix (UMo/Al) is a promising fuel for conversion of the research reactors that currently use HEU fuels to LEUfueled reactors due to its high density and good irradiation stability. Several models have been developed for the estimation of the thermal conductivity of U–Mo fuel, mainly based on the best fit of the very few measured data without providing uncertainty ranges. The purpose of this study is to provide a reasonable estimation of the upper bounds and lower bounds of fuel temperatures with burnup through the evaluation of the uncertainties in the thermal conductivity of irradiated U-Mo/Al dispersion fuel. The combined uncertainty study using RSS method evaluated the effect of applying all the uncertainty values of all the parameters on the operational temperature of U-Mo/Al fuel. The overall influence on the value of the operational temperature is 16.58 .deg. C at the beginning of life and it increases as the burnup increases to reach 18.74 .deg. C at a fuel meat fission density of 3.50E+21 fission/cm{sup 3}. Further studies are needed to evaluate the behavior more accurately by including other parameters uncertainties such as the interaction layer thermal conductivity.

Aging effect on the fuel behaviors for CANDU fuel safety analysis

Energy Technology Data Exchange (ETDEWEB)

Jung, J.Y.; Bae, J.H.; Park, J.H.; Song, Y.M., E-mail: agahee@kaeri.re.kr [Korea Atomic Energy Research Inst., Yuseong-gu, Daejeon (Korea, Republic of)

2013-07-01

Because of the aging of heat transport system components, the reactor thermalhydraulic conditions can vary, which may affect the safety response. In a recent safety analysis for the refurbished Wolsong 1 NPP, various aging effects were incorporated into the hydraulic models of the components in the primary heat transport system (PHTS) for conservatism. The aging data of the thermal-hydraulic components for an 11 EFPY of Wolsong 1 were derived based on the site operation data and were modified to the appropriate input data for the thermal-hydraulic code for a safety analysis of a postulated accident. This paper deals with the aging effect of the PHTS of the CANDU reactor on the fuel performance during normal operation and transient period following a postulated accident such as a feeder stagnation break. (author)

Numerical study of assembly pressure effect on the performance of proton exchange membrane fuel cell

Energy Technology Data Exchange (ETDEWEB)

Taymaz, Imdat; Benli, Merthan [Department of Mechanical Engineering, University of Sakarya, 54187 Adapazari (Turkey)

2010-05-15

The performance of the fuel cell is affected by many parameters. One of these parameters is assembly pressure that changes the mechanical properties and dimensions of the fuel cell components. Its first duty, however, is to prevent gas or liquid leakage from the cell and it is important for the contact behaviors of fuel cell components. Some leakage and contact problems can occur on the low assembly pressures whereas at high pressures, components of the fuel cell, such as bipolar plates (BPP), gas diffusion layers (GDL), catalyst layers, and membranes, can be damaged. A finite element analysis (FEA) model is developed to predict the deformation effect of assembly pressure on the single channel PEM fuel cell in this study. Deformed fuel cell single channel model is imported to three-dimensional, computational fluid dynamics (CFD) model which is developed for simulating proton exchange membrane (PEM) fuel cells. Using this model, the effect of assembly pressure on fuel cell performance can be calculated. It is found that, when the assembly pressure increases, contact resistance, porosity and thickness of the gas diffusion layer (GDL) decreases. Too much assembly pressure causes GDL to destroy; therefore, the optimal assembly pressure is significant to obtain the highest performance from fuel cell. By using the results of this study, optimum fuel cell design and operating condition parameters can be predicted accordingly. (author)

Evaluation of parameters effect on the maximum fuel temperature in the core thermal and hydraulic design of HTTR

International Nuclear Information System (INIS)

Fujimoto, Nozomu; Maruyama, Soh; Sudo, Yukio; Fujii, Sadao; Niguma, Yoshinori.

1988-10-01

This report presents the results of quantitative evaluation on the effects of the dominant parameters on the maximum fuel temperature in the core thermal hydraulic design of the High Temperature Engineering Test Reactor(HTTR) of 30 MW in thermal power, 950 deg C in reactor outlet coolant temperature and 40 kg/cm 2 G in coolant pressure. The dominant parameters investigated are 1) Gap conductance. 2) Effect of eccertricity of fuel compacts in graphite sleeve. 3) Effect of spacer ribs on heat transfer coefficients. 4) Contact probability of fuel compact and graphite sleeve. 5) Validity of uniform radial power density in the fuel compacts. 6) Effect of impurity gas on gap conductance. 7) Effect of FP gas on gap conductance. The effects of these items on the maximum fuel temperature were quantitalively identified as hot spot factors. A probability of the appearance of the maximum fuel temperature was also evaluated in this report. (author)

Atomic-scale effects of chromium-doping on defect behaviour in uranium dioxide fuel

Energy Technology Data Exchange (ETDEWEB)

Guo, Zhexi; Ngayam-Happy, Raoul, E-mail: raoul.ngayam-happy@psi.ch; Krack, Matthias; Pautz, Andreas

2017-05-15

The effects of doping conventional UO{sub 2} fuel with chromium are studied through atomistic simulations using empirical force field methods. We first analyse the stable structures of unirradiated doped fuel by determining the preferred lattice configuration of chromium ions and oxygen vacancies within the matrix. In order to understand the physical effects of the dopants, we investigate the energy change upon inserting isolated defects and Frenkel pairs in the vicinity of chromium. The behaviour of point defects is then studied with collision cascade simulations and relaxation of doped simulation cells containing Frenkel pairs. The defective structures are analysed using an in-house tool named ASTRAM. Results indicate definite effects of chromium-doping on the ease with which defects are formed. Moreover, the extent of Cr effects on the residual damage following a displacement cascade is dependent on the dopant distribution and concentration in the fuel matrix.

Atomic-scale effects of chromium-doping on defect behaviour in uranium dioxide fuel

International Nuclear Information System (INIS)

Guo, Zhexi; Ngayam-Happy, Raoul; Krack, Matthias; Pautz, Andreas

2017-01-01

The effects of doping conventional UO 2 fuel with chromium are studied through atomistic simulations using empirical force field methods. We first analyse the stable structures of unirradiated doped fuel by determining the preferred lattice configuration of chromium ions and oxygen vacancies within the matrix. In order to understand the physical effects of the dopants, we investigate the energy change upon inserting isolated defects and Frenkel pairs in the vicinity of chromium. The behaviour of point defects is then studied with collision cascade simulations and relaxation of doped simulation cells containing Frenkel pairs. The defective structures are analysed using an in-house tool named ASTRAM. Results indicate definite effects of chromium-doping on the ease with which defects are formed. Moreover, the extent of Cr effects on the residual damage following a displacement cascade is dependent on the dopant distribution and concentration in the fuel matrix.

Effect of reactor radiation on the thermal conductivity of TREAT fuel

Energy Technology Data Exchange (ETDEWEB)

Mo, Kun, E-mail: kunmo@anl.gov; Miao, Yinbin; Kontogeorgakos, Dimitrios C.; Connaway, Heather M.; Wright, Arthur E.; Yacout, Abdellatif M.

2017-04-15

The Transient Reactor Test Facility (TREAT) at the Idaho National Laboratory is resuming operations after more than 20 years in latency in order to produce high-neutron-flux transients for investigating transient-induced behavior of reactor fuels and their interactions with other materials and structures. A parallel program is ongoing to develop a replacement core in which the fuel, historically containing highly-enriched uranium (HEU), is replaced by low-enriched uranium (LEU). Both the HEU and prospective LEU fuels are in the form of UO{sub 2} particles dispersed in a graphite matrix, but the LEU fuel will contain a much higher volume of UO{sub 2} particles, which may create a larger area of interphase boundaries between the particles and the graphite. This may lead to a higher volume fraction of graphite exposed to the fission fragments escaping from the UO{sub 2} particles, and thus may induce a higher volume of fission-fragment damage on the fuel graphite. In this work, we analyzed the reactor-radiation induced thermal conductivity degradation of graphite-based dispersion fuel. A semi-empirical method to model the relative thermal conductivity with reactor radiation was proposed and validated based on the available experimental data. Prediction of thermal conductivity degradation of LEU TREAT fuel during a long-term operation was performed, with a focus on the effect of UO{sub 2} particle size on fission-fragment damage. The proposed method can be further adjusted to evaluate the degradation of other properties of graphite-based dispersion fuel.

Theoretical study of the effects of pilot fuel quantity and its injection timing on the performance and emissions of a dual fuel diesel engine

International Nuclear Information System (INIS)

Papagiannakis, R.G.; Hountalas, D.T.; Rakopoulos, C.D.

2007-01-01

Various solutions have been proposed for improving the combustion process of conventional diesel engines and reducing the exhaust emissions without making serious modifications on the engine, one of which is the use of natural gas as a supplement for the conventional diesel fuel, the so called dual fuel natural gas diesel engines. The most common type of these is referred to as the pilot ignited natural gas diesel engine (PINGDE). Here, the primary fuel is natural gas that controls the engine power output, while the pilot diesel fuel injected near the end of the compression stroke auto-ignites and creates ignition sources for the surrounding gaseous fuel mixture to be burned. Previous research studies have shown that the main disadvantage of this dual fuel combustion is its negative impact on engine efficiency compared to the normal diesel operation, while carbon monoxide emissions are also increased. The pilot diesel fuel quantity and injection advance influence significantly the combustion mechanism. Then, in order to examine the effect of these two parameters on the performance and emissions, a comprehensive two-zone phenomenological model is employed and applied on a high-speed, pilot ignited, natural gas diesel engine located at the authors' laboratory. According to the results, the simultaneously increase of the pilot fuel quantity accompanied with an increase of its injection timing results to an improvement of the engine efficiency (increase) and of the emitted CO emissions (decrease) while it has a negative effect (increase) of NO emissions

PIE and separate effect test of high burnup UO2 fuel

International Nuclear Information System (INIS)

Yang, Yong Sik; Kim, S.K.; Kim, D.H.

2005-01-01

To investigate the performance of a high burnup UO 2 fuel, the highest burnup fuel assembly in KOREA was transported to the PIE facility in KAERI. It was a 17·17 fuel assembly irradiated at the Ulchin Unit 2 PWR. The peak fuel rod average burnup was about 57MWd/kgU and locally 65MWd/kgU. The general PIE was performed to investigate the fuel rod irradiation performance. Fission gas release, burnup, oxide thickness, hydrogen pickup, CRUD, and density change were measured by destructive of non-destructive test. Microstructure change, bubble and pore size distributions were observed by optical microscopy, SEM and EPMA. All generated and available PIE results were used to verify high burnup fuel performance code INFRA. Several rods were cut for additional separate effect test. For the high burnup fission gas release behaviour analysis, annealing apparatus were developed and installed in hot cell and preliminary test was performed. In addition to current apparatus new induction furnace will be installed in hot cell to investigate the high temperature and transient fission gas release behaviour. Ring tensile test was performed to analyze the material property degradation which caused by the oxidation and hydride, and additional mechanical tests will be performed. (Author)

Auxiliary aggregates: Effects on fuel consumption and potential fuel savings; Einfluss und Potenzial von Nebenaggregaten auf den Kraftstoffverbrauch

Energy Technology Data Exchange (ETDEWEB)

Rauchfuss, Lutz; Hindorf, Kay [Robert Bosch GmbH (Germany)

2008-07-01

New concepts and new developments in the field of auxiliary aggregates will help to reduce fuel consumption in the future. One aspect is the higher efficiency of components, the other on-demand power supply management. The contribution shows that thermomanagement, intelligent generator control, the start/stop system, auxiliary power control and fuel pumps may achieve considerable savings in the driving cycle and also in real operation. Efficient air conditioning systems and higher generator efficiency will show their potential in real operation. Cost-profit analyses are presented to prove the economic effects for the customer. (orig.)

Effects of Fuel Quantity on Soot Formation Process for Biomass-Based Renewable Diesel Fuel Combustion

KAUST Repository

Jing, Wei

2016-12-01

Soot formation process was investigated for biomass-based renewable diesel fuel, such as biomass to liquid (BTL), and conventional diesel combustion under varied fuel quantities injected into a constant volume combustion chamber. Soot measurement was implemented by two-color pyrometry under quiescent type diesel engine conditions (1000 K and 21% O2 concentration). Different fuel quantities, which correspond to different injection widths from 0.5 ms to 2 ms under constant injection pressure (1000 bar), were used to simulate different loads in engines. For a given fuel, soot temperature and KL factor show a different trend at initial stage for different fuel quantities, where a higher soot temperature can be found in a small fuel quantity case but a higher KL factor is observed in a large fuel quantity case generally. Another difference occurs at the end of combustion due to the termination of fuel injection. Additionally, BTL flame has a lower soot temperature, especially under a larger fuel quantity (2 ms injection width). Meanwhile, average soot level is lower for BTL flame, especially under a lower fuel quantity (0.5 ms injection width). BTL shows an overall low sooting behavior with low soot temperature compared to diesel, however, trade-off between soot level and soot temperature needs to be carefully selected when different loads are used.

Effects of Fuel and Nozzle Characteristics on Micro Gas Turbine System: A Review

Science.gov (United States)

Akasha Hashim, Muhammad; Khalid, Amir; Salleh, Hamidon; Sunar, Norshuhaila Mohamed

2017-08-01

For many decades, gas turbines have been used widely in the internal combustion engine industry. Due to the deficiency of fossil fuel and the concern of global warming, the used of bio-gas have been recognized as one of most clean fuels in the application of engine to improve performance of lean combustion and minimize the production of NOX and PM. This review paper is to understand the combustion performance using dual-fuel nozzle for a micro gas turbine that was basically designed as a natural gas fuelled engine, the nozzle characteristics of the micro gas turbine has been modelled and the effect of multi-fuel used were investigated. The used of biogas (hydrogen) as substitute for liquid fuel (methane) at constant fuel injection velocity, the flame temperature is increased, but the fuel low rate reduced. Applying the blended fuel at constant fuel rate will increased the flame temperature as the hydrogen percentages increased. Micro gas turbines which shows the uniformity of the flow distribution that can be improved without the increase of the pressure drop by applying the variable nozzle diameters into the fuel supply nozzle design. It also identifies the combustion efficiency, better fuel mixing in combustion chamber using duel fuel nozzle with the largest potential for the future. This paper can also be used as a reference source that summarizes the research and development activities on micro gas turbines.

Effect of prenatal exposure to kitchen fuel on birth weight

Directory of Open Access Journals (Sweden)

Yugantara Ramesh Kadam

2013-01-01

Full Text Available Background: Maternal exposure to kitchen fuel smoke may lead to impaired fetal growth. Objective: To study the effect of exposure to various kitchen fuels on birth weight. Methodology : Study type: Retrospective analytical. Study setting: Hospital based. Study Subjects: Mothers and their newborns. Inclusion Criteria: Mothers registered in first trimester with minimum 3 visits, non-anemic, full-term, and singleton delivery. Exclusion Criteria: History of Pregnancy Induced Hypertension (PIH, Diabetes Mellitus (DM, tobacco chewers or mishri users. Sample size: 328 mothers and their new-borne. Study period: Six months. Study tools: Chi-square, Z-test, ANOVA, and binary logistic regression. Results: Effect of confounders on birth weight was tested and found to be non-significant. Mean ± SD of birth weight was 2.669 ± 0.442 in Liquid Petroleium Gas (LPG users (n = 178, 2.465 ± 0.465 in wood users (n = 94, 2.557 ± 0.603 in LPG + wood users (n = 27 and 2.617 ± 0.470 in kerosene users (n = 29. Infants born to wood users had lowest birth weight and averagely 204 g lighter than LPG users (F = 4.056, P < 0.01. Percentage of newborns with low birth weight (LBW in wood users was 44.68% which was significantly higher than in LPG users (24.16%, LPG + wood users (40.74% and in kerosene users (34.48% (Chi-square = 12.926, P < 0.01. As duration of exposure to wood fuel increases there is significant decline in birth weight (F = 3.825, P < 0.05. By using logistic regression type of fuel is only best predictor. Conclusion: Cooking with wood fuel is a significant risk-factor for LBW, which is modifiable.

Global radiative effects of solid fuel cookstove aerosol emissions

Science.gov (United States)

Huang, Yaoxian; Unger, Nadine; Storelvmo, Trude; Harper, Kandice; Zheng, Yiqi; Heyes, Chris

2018-04-01

We apply the NCAR CAM5-Chem global aerosol-climate model to quantify the net global radiative effects of black and organic carbon aerosols from global and Indian solid fuel cookstove emissions for the year 2010. Our assessment accounts for the direct radiative effects, changes to cloud albedo and lifetime (aerosol indirect effect, AIE), impacts on clouds via the vertical temperature profile (semi-direct effect, SDE) and changes in the surface albedo of snow and ice (surface albedo effect). In addition, we provide the first estimate of household solid fuel black carbon emission effects on ice clouds. Anthropogenic emissions are from the IIASA GAINS ECLIPSE V5a inventory. A global dataset of black carbon (BC) and organic aerosol (OA) measurements from surface sites and aerosol optical depth (AOD) from AERONET is used to evaluate the model skill. Compared with observations, the model successfully reproduces the spatial patterns of atmospheric BC and OA concentrations, and agrees with measurements to within a factor of 2. Globally, the simulated AOD agrees well with observations, with a normalized mean bias close to zero. However, the model tends to underestimate AOD over India and China by ˜ 19 ± 4 % but overestimate it over Africa by ˜ 25 ± 11 % (± represents modeled temporal standard deviations for n = 5 run years). Without BC serving as ice nuclei (IN), global and Indian solid fuel cookstove aerosol emissions have net global cooling radiative effects of -141 ± 4 mW m-2 and -12 ± 4 mW m-2, respectively (± represents modeled temporal standard deviations for n = 5 run years). The net radiative impacts are dominated by the AIE and SDE mechanisms, which originate from enhanced cloud condensation nuclei concentrations for the formation of liquid and mixed-phase clouds, and a suppression of convective transport of water vapor from the lower troposphere to the upper troposphere/lower stratosphere that in turn leads to reduced ice cloud formation. When BC is allowed

Advanced fuel system technology for utilizing broadened property aircraft fuels

Science.gov (United States)

Reck, G. M.

1980-01-01

Possible changes in fuel properties are identified based on current trends and projections. The effect of those changes with respect to the aircraft fuel system are examined and some technological approaches to utilizing those fuels are described.

Fuel cycles with high fuel burn-up: analysis of reactivity coefficients

Energy Technology Data Exchange (ETDEWEB)

Kryuchkov, E.F.; Shmelev, A.N.; Ternovykh, M.J.; Tikhomirov, G.V.; Jinhong, L. [Moscow Engineering Physics Institute (State University) (Russian Federation); Saito, M. [Tokyo Institute of Technology (Japan)

2003-07-01

Fuel cycles of light-water reactors (LWR) with high fuel burn-up (above 100 MWd/kg), as a rule, involve large amounts of fissionable materials. It leads to forming the neutron spectrum harder than that in traditional LWR. Change of neutron spectrum and significant amount of non-traditional isotopes (for example, {sup 237}Np, {sup 238}Pu, {sup 231}Pa, {sup 232}U) in such fuel compositions can alter substantially reactivity coefficients as compared with traditional uranium-based fuel. The present work addresses the fuel cycles with high fuel burn-up which are based on Th-Pa-U and U-Np-Pu fuel compositions. Numerical analyses are carried out to determine effective neutron multiplication factor and void reactivity coefficient (VRC) for different values of fuel burn-up and different lattice parameters. The algorithm is proposed for analysis of isotopes contribution to these coefficients. Various ways are considered to upgrade safety of nuclear fuel cycles with high fuel burn-up. So, the results obtained in this study have demonstrated that: -1) Non-traditional fuel compositions developed for achievement of high fuel burn-up in LWR can possess positive values of reactivity coefficients that is unacceptable from the reactor operation safety point of view; -2) The lattice pitch of traditional LWR is not optimal for non-traditional fuel compositions, the increased value of the lattice pitch leads to larger value of initial reactivity margin and provides negative VRC within sufficiently broad range of coolant density; -3) Fuel burn-up has an insignificant effect on VRC dependence on coolant density, so, the measures undertaken to suppress positive VRC of fresh fuel will be effective for partially burnt-up fuel compositions also and; -4) Increase of LWR core height and introduction of additional moderators into the fuel lattice can be used as the ways to reach negative VRC values for full range of possible coolant density variations.

Effects of coal-derived trace species on performance of molten carbonate fuel cells. Final report

Energy Technology Data Exchange (ETDEWEB)

1992-05-01

The Carbonate Fuel Cell is a very promising option for highly efficient generation of electricity from many fuels. If coal-gas is to be used, the interactions of coal-derived impurities on various fuel cell components need to be understood. Thus the effects on Carbonate Fuel Cell performance due to ten different coal-derived contaminants viz., NH{sub 3}, H{sub 2}S, HC{ell}, H{sub 2}Se, AsH{sub 3}, Zn, Pb, Cd, Sn, and Hg, have been studied at Energy Research Corporation. Both experimental and theoretical evaluations were performed, which have led to mechanistic insights and initial estimation of qualitative tolerance levels for each species individually and in combination with other species. The focus of this study was to investigate possible coal-gas contaminant effects on the anode side of the Carbonate Fuel Cell, using both out-of-cell thermogravimetric analysis by isothermal TGA, and fuel cell testing in bench-scale cells. Separate experiments detailing performance decay in these cells with high levels of ammonia contamination (1 vol %) and with trace levels of Cd, Hg, and Sn, have indicated that, on the whole, these elements do not affect carbonate fuel cell performance. However, some performance decay may result when a number of the other six species are present, singly or simultaneously, as contaminants in fuel gas. In all cases, tolerance levels have been estimated for each of the 10 species and preliminary models have been developed for six of them. At this stage the models are limited to isothermal, benchscale (300 cm{sup 2} size) single cells. The information obtained is expected to assist in the development of coal-gas cleanup systems, while the contaminant performance effects data will provide useful basic information for modeling fuel cell endurance in conjunction with integrated gasifier/fuel-cell systems (IGFC).

Fuel choices for fuel-cell vehicles : well-to-wheel energy and emission impacts

International Nuclear Information System (INIS)

Wang, M.

2002-01-01

Because of their high energy efficiencies and low emissions, fuel-cell vehicles (FCVs) are undergoing extensive research and development. While hydrogen will likely be the ultimate fuel to power fuel-cell vehicles, because of current infrastructure constraints, hydrogen-carrying fuels are being investigated as transitional fuel-cell fuels. A complete well-to-wheels (WTW) evaluation of fuel-cell vehicle energy and emission effects that examines (1) energy feedstock recovery and transportation; (2) fuel production, transportation, and distribution; and (3) vehicle operation must be conducted to assist decision makers in selecting the fuel-cell fuels that achieve the greatest energy and emission benefits. A fuel-cycle model developed at Argonne National Laboratory--called the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model--was used to evaluate well-to-wheels energy and emission impacts of various fuel-cell fuels. The results show that different fuel-cell fuels can have significantly different energy and greenhouse gas emission effects. Therefore, if fuel-cell vehicles are to achieve the envisioned energy and emission reduction benefits, pathways for producing the fuels that power them must be carefully examined.

Effects of alternative-fuel vehicles on air quality in Ontario, Canada

International Nuclear Information System (INIS)

Kantor, I.; Fowler, M.; Hajimiragha, A.; Canizares, C.; Elkamel, A.

2009-01-01

The economies of the developed world are increasingly including green technologies and processes that consider social, environmental and economic consequences. Hybrid electric vehicles and other fuel-efficient vehicle types can supply consumers with vehicles that decrease their ecological footprint and reduce the cost of fuel. However, one of the societal concerns often overlooked is the impact of alternative-fuel vehicle usage on the air quality in the urban environment. This paper presented a study that assessed the impact on air quality stemming from the operation of alternative fuel vehicles in urban environments. The study specifically focused on the province-wide emissions in Ontario and urban air pollution in the city of Toronto. The paper considered the life-cycle impacts of using alternative fuels for transportation purposes in terms of six major stressors for climate change, acidification and urban air quality. The two types of vehicles that were studied were plug-in hybrid electric vehicles (PHEVs) and fuel cell vehicles. Modeling of the penetration rates for both types of vehicles was completed based on the maximum capacity of the electrical grid including planned improvements. The scope of the study and discussion of health effects was first presented followed by data gathering and usage, methodology, results of supportable penetration and vehicle growth, and pollution abatement results. It was concluded that fuel cell vehicles have an advantage over, or near-equality with, PHEVs in almost every aspect of their emissions. 13 refs., 2 tabs., 10 figs

Numerical investigation of injector geometry effects on fuel stratification in a GCI engine

KAUST Repository

Atef, Nour; Badra, Jihad; Jaasim, Mohammed; Im, Hong G.; Sarathy, Mani

2017-01-01

Injectors play an important role in direct injection (DI) gasoline compression ignition (GCI) engines by affecting the in-cylinder mixture formation and stratification, which in turn impacts combustion and emissions. In this work, the effects of two different injector geometries, a 7-hole solid-cone injector and an outwardly opening hollow-cone injector, on fuel mixture stratification in a GCI engine were investigated by computational simulations. Three fuels with similar autoignition kinetics, but with different physical properties, were studied to isolate the effect of the combustion chemistry on combustion phasing. In addition, start of injection (SOI) sweeps relevant to low-load engine operating conditions were performed. The results show that physical properties of the fuel do not have significant influence when using a hollow-cone injector. Richer mixtures were observed at all the studied SOI (−40 to −14 CAD aTDC) cases, which can be attributed to the nature of the hollow cone spray. At later SOIs (−18 and −14 CAD aTDC), the richer mixtures are accompanied by lower mean in-cylinder temperature due to the charge cooling effect, which surpasses the equivalence ratio effect. The effect of fuel physical properties on combustion phasing was evident in multi-hole injection cases, which can be attributed to the differences in mixture stratification and equivalence ratio distribution at the time of ignition.

Numerical investigation of injector geometry effects on fuel stratification in a GCI engine

KAUST Repository

Atef, Nour

2017-11-24

Injectors play an important role in direct injection (DI) gasoline compression ignition (GCI) engines by affecting the in-cylinder mixture formation and stratification, which in turn impacts combustion and emissions. In this work, the effects of two different injector geometries, a 7-hole solid-cone injector and an outwardly opening hollow-cone injector, on fuel mixture stratification in a GCI engine were investigated by computational simulations. Three fuels with similar autoignition kinetics, but with different physical properties, were studied to isolate the effect of the combustion chemistry on combustion phasing. In addition, start of injection (SOI) sweeps relevant to low-load engine operating conditions were performed. The results show that physical properties of the fuel do not have significant influence when using a hollow-cone injector. Richer mixtures were observed at all the studied SOI (−40 to −14 CAD aTDC) cases, which can be attributed to the nature of the hollow cone spray. At later SOIs (−18 and −14 CAD aTDC), the richer mixtures are accompanied by lower mean in-cylinder temperature due to the charge cooling effect, which surpasses the equivalence ratio effect. The effect of fuel physical properties on combustion phasing was evident in multi-hole injection cases, which can be attributed to the differences in mixture stratification and equivalence ratio distribution at the time of ignition.

Diesel Emission Control -- Sulfur Effects (DECSE) Program; Phase I Interim Date Report No. 3: Diesel Fuel Sulfur Effects on Particulate Matter Emissions

Energy Technology Data Exchange (ETDEWEB)

DOE; ORNL; NREL; EMA; MECA

1999-11-15

The Diesel Emission Control-Sulfur Effects (DECSE) is a joint government/industry program to determine the impact of diesel fuel sulfur levels on emission control systems whose use could lower emissions of nitrogen oxides (NO{sub x}) and particulate matter (PM) from on-highway trucks in the 2002--2004 model years. Phase 1 of the program was developed with the following objectives in mind: (1) evaluate the effects of varying the level of sulfur content in the fuel on the emission reduction performance of four emission control technologies; and (2) measure and compare the effects of up to 250 hours of aging on selected devices for multiple levels of fuel sulfur content. This interim report covers the effects of diesel fuel sulfur level on particulate matter emissions for four technologies.

Dwarf mistletoe effects on fuel loadings in ponderosa pine forests in northern Arizona

Science.gov (United States)

Chad Hoffman; Robert Mathiasen; Carolyn Hull Sieg

2007-01-01

Southwestern dwarf mistletoe (Arceuthobium vaginatum (Willd.) J. Presl ssp. cryptopodum) infests about 0.9 million ha in the southwestern United States. Several studies suggest that dwarf mistletoes affect forest fuels and fire behavior; however, few studies have quantified these effects. We compared surface fuel loadings and...

77 FR 59458 - Regulation of Fuels and Fuel Additives: 2013 Biomass-Based Diesel Renewable Fuel Volume

Science.gov (United States)

2012-09-27

... gasoline and diesel fuel or renewable fuels such as ethanol and biodiesel. Potentially regulated categories... of Biodiesel 1. Grease and Rendered Fats 2. Corn Oil 3. Soybean Oil 4. Effects on Food Prices 5.... Deliverability and Transport Costs of Materials, Goods, and Products Other Than Renewable Fuel 6. Wetlands...

PWR fuel thermomechanics

International Nuclear Information System (INIS)

Traccucci, R.; Leclercq, J.

1986-01-01

Fuel thermo-mechanics means the studies of mechanical and thermal effects, and more generally, the studies of the behavior of the fuel assembly under stresses including thermal and mechanical loads, hydraulic effects and phenomena induced by materials irradiation. This paper describes the studies dealing with the fuel assembly behavior, first in normal operating conditions, and then in accidental conditions. 43 refs [fr

Apparatus for loading fuel pellets in fuel rods

International Nuclear Information System (INIS)

Tedesco, R.J.

1976-01-01

An apparatus is disclosed for loading fuel pellets into fuel rods for a nuclear reactor including a base supporting a table having grooves therein for holding a multiplicity of pellets. Multiple fuel rods are placed in alignment with grooves in the pellet table and a guide member channels pellets from the table into the corresponding fuel rods. To effect movement of pellets inside the fuel rods without jamming, a number of electromechanical devices mounted on the base have arms connected to the lower surface of the fuel rod table which cyclically imparts a reciprocating arc motion to the table for moving the fuel pellets longitudinally of and inside the fuel rods. These electromechanical devices include a solenoid having a plunger therein connected to a leaf type spring, the arrangement being such that upon energization of the solenoid coil, the leaf spring moves the fuel rod table rearwardly and downwardly, and upon deenergization of the coil, the spring imparts an upward-forward movement to the table which results in physical displacement of fuel pellets in the fuel rods clamped to the table surface. 8 claims, 6 drawing figures

Fuel accumulation and forest structure change following hazardous fuel reduction treatments throughout California

Science.gov (United States)

Nicole M. Vaillant; Erin K. Noonan-Wright; Alicia L. Reiner; Carol M. Ewell; Benjamin M. Rau; Josephine A. Fites-Kaufman; Scott N. Dailey

2015-01-01

Altered fuel conditions coupled with changing climate have disrupted fire regimes of forests historically characterised by high-frequency and low-to-moderate-severity fire. Managers use fuel treatments to abate undesirable fire behaviour and effects. Short-term effectiveness of fuel treatments to alter fire behaviour and effects is well documented; however, long-term...

KMRR fuel design

International Nuclear Information System (INIS)

Son, D.S.; Sim, B.S.; Kim, T.R.; Hwang, W.; Kim, B.G.; Ku, Y.H.; Lee, C.B.; Lim, I.C.

1992-06-01

KMRR fuel rod design criteria on fuel swelling, blistering and oxide spallation have been reexamined. Fuel centerline temperature limit of 250deg C in normal operation condition and fuel swelling limit of 12 % at the end of life have been proposed to prevent fuel failure due to excessive fuel swelling. Fuel temperature limit of 485deg C has been proposed to exclude the possibility of fuel failures during transients or under accident condition. Further analyses are needed to decide the fuel cladding temperature limit to preclude the oxide spallation. Design changes in fuel assembly structure and their effects on related systems have been reviewed from a structural integrity viewpoint. The remained works in fuel mechanical design area have been identified and further efforts of fuel design group will be focused on these aspects. (Author)

Effects of pellet shape on the fuel failure behavior under a RIA condition

International Nuclear Information System (INIS)

Hosokawa, Takanori; Hoshi, Tsutao; Yanagihara, Satoshi; Iwamura, Takamichi; Orita, Yoshihiko.

1980-10-01

The two types of fuel rods with different pellet shaped, i.e. flat pellets and dished pellets, were tested in the NSRR to investigate the effects of pellet shapes on the fuel failure behavior under an RIA condition and the results were compared with those of the chamfered pellet fuel rods which are used as the reference rod in the NSRR experiments. In addition, the deformation of pellets due to thermal expansion is calculated by using an FEM computer code. Through the above results, following conclusions are obtained. (1) In the experiments, insignificant differences on the cladding surface temperature responses and the appearance of post-irradiated rods are observed in each type of rods. (2) Evident differences on the deformation of fuel pellets have not appeared in the calculation. (3) In the RIA conditions, it is concluded that the fuel failure behavior and threshold energy might not be affected by pellet shape of which size is in the range of the current LWR's fuel rods. (author)

The investigation of effects specific fuel comsumption and emissions fuel mixtures nitromethane

Directory of Open Access Journals (Sweden)

Samet Çelebi

2013-08-01

Full Text Available In this study, changes of specific fuel consumption and exhaust emmission values of chemical produced nitromethane are compared with values of gasoline fuel. In motor tests conducted at full load, gasoline mixture including % 5 nitromethane yield decreased specific fuel consumption value of 3200 min-1 and low engine speed of % 6,18 percentage. On the other hand, engine power is increased. While CO and HC emissions were observed to be less than gasoline, CO2 and NOx emissions remained to be increased. In performed tests, it is also observed that when mixing nitromethane with % 10 more gasoline, over knocking and unstable motor behavior is observed.

Fuel cells for electricity generation from carbonaceous fuels

Energy Technology Data Exchange (ETDEWEB)

Ledjeff-Hey, K; Formanski, V; Roes, J [Gerhard-Mercator- Universitaet - Gesamthochschule Duisburg, Fachbereich Maschinenbau/Fachgebiet Energietechnik, Duisburg (Germany); Heinzel, A [Fraunhofer Inst. for Solar Energy Systems (ISE), Freiburg (Germany)

1998-09-01

Fuel cells, which are electrochemical systems converting chemical energy directly into electrical energy with water and heat as by-products, are of interest as a means of generating electricity which is environmentally friendly, clean and highly efficient. They are classified according to the electrolyte used. The main types of cell in order of operating temperature are described. These are: alkaline fuel cells, the polymer electrolyte membrane fuel cell (PEMFC); the phosphoric acid fuel cell (PAFC); the molten carbonate fuel cell (MCFC); the solid oxide fuel cell (SOFC). Applications depend on the type of cell and may range from power generation on a large scale to mobile application in cars or portable systems. One of the most promising options is the PEM-fuel cell stack where there has been significant improvement in power density in recent years. The production from carbonaceous fuels and purification of the cell fuel, hydrogen, is considered. Of the purification methods available, hydrogen separation by means of palladium alloy membranes seems particular effective in reducing CO concentrations to the low levels required for PEM cells. (UK)

Fuel assembly

International Nuclear Information System (INIS)

Nomata, Terumitsu.

1993-01-01

Among fuel pellets to be loaded to fuel cans of a fuel assembly, fuel pellets having a small thermal power are charged in a region from the end of each of spacers up to about 50mm on the upstream of coolants that flow vertically at the periphery of fuel rods. Coolants at the periphery of fuel rods are heated by the heat generation, to result in voids. However, since cooling effect on the upstream of the spacers is low due to influences of the spacers. Further, since the fuel pellets disposed in the upstream region have small thermal power, a void coefficient is not increased. Even if a thermal power exceeding cooling performance should be generated, there is no worry of causing burnout in the upstream region. Even if burnout should be caused, safety margin and reliability relative to burnout are improved, to increase an allowable thermal power, thereby enabling to improve integrity and reliability of fuel rods and fuel assemblies. (N.H.)

BWR fuel performance

International Nuclear Information System (INIS)

Baily, W.E.; Armijo, J.S.; Jacobson, J.; Proebstle, R.A.

1979-01-01

The General Electric experience base on BWR fuel includes over 29,000 fuel assemblies which contain 1,600,000 fuel rods. Over the last five years, design, process and operating changes have been introduced which have had major effects in improving fuel performance. Monitoring this fuel performance in BWRs has been accomplished through cooperative programs between GE and utilities. Activities such as plant fission product monitoring, fuel sipping and fuel and channel surveillance programs have jointly contributed to the value of this extensive experience base. The systematic evaluation of this data has established well-defined fuel performance trends which provide the assurance and confidence in fuel reliability that only actual operating experience can provide

The effect of non-uniform fuel rod temperatures on effective resonance integrals

International Nuclear Information System (INIS)

Reichel, A.

1961-06-01

The effective resonance integral for heterogeneous lattices can be reduced to the effective resonance integral for an equivalent homogeneous system with a fairly well defined error depending on lump size and geometry. This report investigates the effect of a radial parabolic temperature variation in cylindrical lumps on the equivalent homogeneous effective resonance integral. Also determined is the equivalent uniform temperature to be taken in the usual formulae to allow for non-uniform fuel rod temperature. This effective temperature is found to be T eff. = T s + 4/9 (T c - T s ) where T s and T c are the surface and central temperatures of the lump. (author)

2000 Annual Progress Report for Fuels for Advanced CIDI Engines and Fuel Cells

Energy Technology Data Exchange (ETDEWEB)

Chalk, S.

2000-12-11

The Department of Energy's Office of Transportation Technologies Fiscal Year (FY) 2000 Annual Progress Report for the Fuels for Advanced CIDI Engines and Fuel Cells Program highlights progress achieved during FY 2000 and comprises 22 summaries of industry and National Laboratory projects that were conducted. The report provides an overview of the exciting work being conducted to tackle the tough technical challenges associated with developing clean burning fuels that will enable meeting the performance goals of the Emission Control R and D for Advanced CIDI Engines and the Transportation Fuel Cell Power Systems Programs. The summaries cover the effects of CIDI engine emissions and fuel cell power system performance, the effects of lubricants on engine emissions, the effects of fuel and consumed lubricants on exhaust emission control devices and the health and safety, materials compatibility, and economics of advanced petroleum-based fuels.

The effect of dissolved hydrogen on the dissolution of 233U doped UO2(s) high burn-up spent fuel and MOX fuel

International Nuclear Information System (INIS)

Carbol, P.; Spahiu, K.

2005-03-01

In this report the results of the experimental work carried out in a large EU-research project (SFS, 2001-2004) on spent fuel stability in the presence of various amounts of near field hydrogen are presented. Studies of the dissolution of 233 U doped UO 2 (s) simulating 'old' spent fuel were carried out as static leaching tests, autoclave tests with various hydrogen concentrations and electrochemical tests. The results of the leaching behaviour of a high burn-up spent fuel pellet in 5 M NaCl solutions in the presence of 3.2 bar H 2 pressure and of MOX fuel in dilute synthetic groundwater under 53 bar H 2 pressure are also presented. In all the experimental studies carried out in this project, a considerable effect of hydrogen in the dissolution rates of radioactive materials was observed. The experimental results obtained in this project with a-doped UO 2 , high burn-up spent fuel and MOX fuel together with literature data give a reliable background to use fractional alteration/dissolution rates for spent fuel of the order of 10 -6 /yr - 10 -8 /yr with a recommended value of 4x10 -7 /yr for dissolved hydrogen concentrations above 10 -3 M and Fe(II) concentrations typical for European repository concepts. Finally, based on a review of the experimental data and available literature data, potential mechanisms of the hydrogen effect are also discussed. The work reported in this document was performed as part of the Project SFS of the European Commission 5th Framework Programme under contract no FIKW-CT-2001-20192 SFS. It represents the deliverable D10 of the experimental work package 'Key experiments using a-doped UO 2 and real spent fuel', coordinated by SKB with the participation of ITU, FZK-INE, ENRESA, CIEMAT, ARMINES-SUBATECH and SKB

Spent fuel workshop'2002

International Nuclear Information System (INIS)

Poinssot, Ch.

2002-01-01

This document gathers the transparencies of the presentations given at the 2002 spent fuel workshop: Session 1 - Research Projects: Overview on the IN CAN PROCESSES European project (M. Cowper), Overview on the SPENT FUEL STABILITY European project (C. Poinssot), Overview on the French R and D project on spent fuel long term evolution, PRECCI (C. Poinssot); Session 2 - Spent Fuel Oxidation: Oxidation of uranium dioxide single crystals (F. Garrido), Experimental results on SF oxidation and new modeling approach (L. Desgranges), LWR spent fuel oxidation - effects of burn-up and humidity (B. Hanson), An approach to modeling CANDU fuel oxidation under dry storage conditions (P. Taylor); Session 3 - Spent Fuel Dissolution Experiments: Overview on high burnup spent fuel dissolution studies at FZK/INE (A. Loida), Results on the influence of hydrogen on spent fuel leaching (K. Spahiu), Leaching of spent UO 2 fuel under inert and reducing conditions (Y. Albinsson), Fuel corrosion investigation by electrochemical techniques (D. Wegen), A reanalysis of LWR spent fuel flow through dissolution tests (B. Hanson), U-bearing secondary phases formed during fuel corrosion (R. Finch), The near-field chemical conditions and spent fuel leaching (D. Cui), The release of radionuclides from spent fuel in bentonite block (S.S. Kim), Trace actinide behavior in altered spent fuel (E. Buck, B. Hanson); Session 4 - Radiolysis Issues: The effect of radiolysis on UO 2 dissolution determined from electrochemical experiments with 238 Pu doped UO 2 M. Stroess-Gascoyne (F. King, J.S. Betteridge, F. Garisto), doped UO 2 studies (V. Rondinella), Preliminary results of static and dynamic dissolution tests with α doped UO 2 in Boom clay conditions (K. Lemmens), Studies of the behavior of UO 2 / water interfaces under He 2+ beam (C. Corbel), Alpha and gamma radiolysis effects on UO 2 alteration in water (C. Jegou), Behavior of Pu-doped pellets in brines (M. Kelm), On the potential catalytic behavior of

Radiation and Thermal Effects on Used Nuclear Fuel and Nuclear Waste Forms

Energy Technology Data Exchange (ETDEWEB)

Weber, William J. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering; Zhang, Yanwen [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering

2016-09-20

This is the final report of the NEUP project “Radiation and Thermal Effects on Used Nuclear Fuel and Nuclear Waste Forms.” This project started on July 1, 2012 and was successfully completed on June 30, 2016. This report provides an overview of the main achievements, results and findings through the duration of the project. Additional details can be found in the main body of this report and in the individual Quarterly Reports and associated Deliverables of this project, which have been uploaded in PICS-NE. The objective of this research was to advance understanding and develop validated models on the effects of self-radiation from beta and alpha decay on the response of used nuclear fuel and nuclear waste forms during high-temperature interim storage and long-term permanent disposition. To achieve this objective, model used-fuel materials and model waste form materials were identified, fabricated, and studied.

An optimized BWR fuel lattice for improved fuel utilization

International Nuclear Information System (INIS)

Bernander, O.; Helmersson, S.; Schoen, C.G.

1984-01-01

Optimization of the BWR fuel lattice has evolved into the water cross concept, termed ''SVEA'', whereby the improved moderation within bundles augments reactivity and thus improves fuel cycle economy. The novel design introduces into the assembly a cruciform and double-walled partition containing nonboiling water, thus forming four subchannels, each of which holds a 4x4 fuel rod bundle. In Scandinavian BWRs - for which commercial SVEA reloads are now scheduled - the reactivity gain is well exploited without adverse impact in other respects. In effect, the water cross design improves both mechanical and thermal-hydraulic performance. Increased average burnup is also promoted through achieving flatter local power distributions. The fuel utilization savings are in the order of 10%, depending on the basis of comparison, e.g. choice of discharge burnup and lattice type. This paper reviews the design considerations and the fuel utilization benefits of the water cross fuel for non-Scandinavian BWRs which have somewhat different core design parameters relative to ASEA-ATOM reactors. For one design proposal, comparisons are made with current standard 8x8 fuel rod bundles as well as with 9x9 type fuel in reactors with symmetric or asymmetric inter-assembly water gaps. The effect on reactivity coefficients and shutdown margin are estimated and an assessment is made of thermal-hydraulic properties. Consideration is also given to a novel and advantageous way of including mixed-oxide fuel in BWR reloads. (author)

Effects of fuel treatments on carbon-disturbance relationships in forests of the northern Rocky Mountains

Science.gov (United States)

Elizabeth Reinhardt; Lisa Holsinger

2010-01-01

Fuel treatments alter conditions in forested stands at the time of the treatment and subsequently. Fuel treatments reduce on-site carbon and also change the fire potential and expected outcome of future wildfires, including their carbon emissions. We simulated effects of fuel treatments on 140 stands representing seven major habitat type groups of the northern Rocky...

Fissile fuel doubling time characteristics for reactor lifetime fuel logistics

International Nuclear Information System (INIS)

Heindler, M.; Harms, A.A.

1978-01-01

The establishment of nuclear fuel requirements and their efficient utilization requires a detailed knowledge of some aspects of fuel dynamics and processing during the reactor lifetime. It is shown here that the use of the fuel stockpile inventory concept can serve effectively for this fuel management purpose. The temporal variation of the fissile fuel doubling time as well as nonequilibrium core conditions are among the characteristics which thus become more evident. These characteristics - rather than a single figure-of-merit - clearly provide an improved description of the expansion capacity and/or fuel requirements of a nuclear reactor energy system

Effects of experimental fuel additions on fire intensity and severity: unexpected carbon resilience of a neotropical forest.

Science.gov (United States)

Brando, Paulo M; Oliveria-Santos, Claudinei; Rocha, Wanderley; Cury, Roberta; Coe, Michael T

2016-07-01

Global changes and associated droughts, heat waves, logging activities, and forest fragmentation may intensify fires in Amazonia by altering forest microclimate and fuel dynamics. To isolate the effects of fuel loads on fire behavior and fire-induced changes in forest carbon cycling, we manipulated fine fuel loads in a fire experiment located in southeast Amazonia. We predicted that a 50% increase in fine fuel loads would disproportionally increase fire intensity and severity (i.e., tree mortality and losses in carbon stocks) due to multiplicative effects of fine fuel loads on the rate of fire spread, fuel consumption, and burned area. The experiment followed a fully replicated randomized block design (N = 6) comprised of unburned control plots and burned plots that were treated with and without fine fuel additions. The fuel addition treatment significantly increased burned area (+22%) and consequently canopy openness (+10%), fine fuel combustion (+5%), and mortality of individuals ≥5 cm in diameter at breast height (dbh; +37%). Surprisingly, we observed nonsignificant effects of the fuel addition treatment on fireline intensity, and no significant differences among the three treatments for (i) mortality of large trees (≥30 cm dbh), (ii) aboveground forest carbon stocks, and (iii) soil respiration. It was also surprising that postfire tree growth and wood increment were higher in the burned plots treated with fuels than in the unburned control. These results suggest that (i) fine fuel load accumulation increases the likelihood of larger understory fires and (ii) single, low-intensity fires weakly influence carbon cycling of this primary neotropical forest, although delayed postfire mortality of large trees may lower carbon stocks over the long term. Overall, our findings indicate that increased fine fuel loads alone are unlikely to create threshold conditions for high-intensity, catastrophic fires during nondrought years. © 2016 John Wiley & Sons Ltd.

Thermal conductivity of U–Mo/Al dispersion fuel. Effects of particle shape and size, stereography, and heat generation

International Nuclear Information System (INIS)

Cho, Tae Won; Sohn, Dong-Seong; Kim, Yeon Soo

2015-01-01

This paper describes the effects of particle sphericity, interfacial thermal resistance, stereography, and heat generation on the thermal conductivity of U–Mo/Al dispersion fuel. The ABAQUS finite element method (FEM) tool was used to calculate the effective thermal conductivity of U–Mo/Al dispersion fuel by implementing fuel particles. For U–Mo/Al, the particle sphericity effect was insignificant. However, if the effect of the interfacial thermal resistance between the fuel particles and Al matrix was considered, the thermal conductivity of U–Mo/Al was increased as the particle size increases. To examine the effect of stereography, we compared the two-dimensional modeling and three-dimensional modeling. The results showed that the two-dimensional modeling predicted lower than the three-dimensional modeling. We also examined the effect of the presence of heat sources in the fuel particles and found a decrease in thermal conductivity of U–Mo/Al from that of the typical homogeneous heat generation modeling. (author)

The effect of copper, MDA, and accelerated aging on jet fuel thermal stability as measured by the gravimetric JFTOT

Energy Technology Data Exchange (ETDEWEB)

Pande, S.G. [Geo-Centers, Inc., Ft. Washington, MD (United States); Hardy, D.R. [Navy Technology Center for Safety and Survivability, Washington, DC (United States)

1995-05-01

Thermally unstable jet fuels pose operational problems. In order to adequately identify such fuels, factors that realistically impact on thermal stability were examined. Evaluation was based on a quantitative method of measuring thermal stability, viz., NRL`s recently developed gravimetric JFTOT. This method gives a quantitative measurement of both the strip deposit and filterables formed. The pertinent factors examined, included the individual and interactive effects of: soluble copper, MDA (metal deactivator), and aging. The latter was accelerated to simulate field conditions of approximately six months aging at ambient temperature and pressure. The results indicate that the individual and interactive effects of copper, MDA, and accelerated aging appear to be fuel dependent. Based on the results, the three test fuels examined (one JP-8 and two JP-5s) were categorized as exhibiting very good, typical, and poor thermal stabilities, respectively. For both the very good and poor thermal stability fuels, the effect of copper in conjunction with accelerated aging did not significantly increase the total thermal deposits of the neat fuels. In contrast, for the typical thermal stability fuel, the combined effects of copper and accelerated aging, did. Furthermore, the addition of MDA prior to aging of the copper-doped, typical stability fuel significantly counteracted the adverse effect of copper and aging. A similar beneficial effect of MDA was not observed for the poor stability fuel. These results focus on the compositional differences among fuels and the need to elucidate these differences (physical and chemical) for a better understanding and prediction of their performance.

Measuring the effect of fuel treatments on forest carbon using landscape risk analysis

Directory of Open Access Journals (Sweden)

A. A. Ager

2010-12-01

Full Text Available Wildfire simulation modelling was used to examine whether fuel reduction treatments can potentially reduce future wildfire emissions and provide carbon benefits. In contrast to previous reports, the current study modelled landscape scale effects of fuel treatments on fire spread and intensity, and used a probabilistic framework to quantify wildfire effects on carbon pools to account for stochastic wildfire occurrence. The study area was a 68 474 ha watershed located on the Fremont-Winema National Forest in southeastern Oregon, USA. Fuel reduction treatments were simulated on 10% of the watershed (19% of federal forestland. We simulated 30 000 wildfires with random ignition locations under both treated and untreated landscapes to estimate the change in burn probability by flame length class resulting from the treatments. Carbon loss functions were then calculated with the Forest Vegetation Simulator for each stand in the study area to quantify change in carbon as a function of flame length. We then calculated the expected change in carbon from a random ignition and wildfire as the sum of the product of the carbon loss and the burn probabilities by flame length class. The expected carbon difference between the non-treatment and treatment scenarios was then calculated to quantify the effect of fuel treatments. Overall, the results show that the carbon loss from implementing fuel reduction treatments exceeded the expected carbon benefit associated with lowered burn probabilities and reduced fire severity on the treated landscape. Thus, fuel management activities resulted in an expected net loss of carbon immediately after treatment. However, the findings represent a point in time estimate (wildfire immediately after treatments, and a temporal analysis with a probabilistic framework used here is needed to model carbon dynamics over the life cycle of the fuel treatments. Of particular importance is the long-term balance between emissions from the

Measuring the effect of fuel treatments on forest carbon using landscape risk analysis

Science.gov (United States)

Ager, A. A.; Finney, M. A.; McMahan, A.; Cathcart, J.

2010-12-01

Wildfire simulation modelling was used to examine whether fuel reduction treatments can potentially reduce future wildfire emissions and provide carbon benefits. In contrast to previous reports, the current study modelled landscape scale effects of fuel treatments on fire spread and intensity, and used a probabilistic framework to quantify wildfire effects on carbon pools to account for stochastic wildfire occurrence. The study area was a 68 474 ha watershed located on the Fremont-Winema National Forest in southeastern Oregon, USA. Fuel reduction treatments were simulated on 10% of the watershed (19% of federal forestland). We simulated 30 000 wildfires with random ignition locations under both treated and untreated landscapes to estimate the change in burn probability by flame length class resulting from the treatments. Carbon loss functions were then calculated with the Forest Vegetation Simulator for each stand in the study area to quantify change in carbon as a function of flame length. We then calculated the expected change in carbon from a random ignition and wildfire as the sum of the product of the carbon loss and the burn probabilities by flame length class. The expected carbon difference between the non-treatment and treatment scenarios was then calculated to quantify the effect of fuel treatments. Overall, the results show that the carbon loss from implementing fuel reduction treatments exceeded the expected carbon benefit associated with lowered burn probabilities and reduced fire severity on the treated landscape. Thus, fuel management activities resulted in an expected net loss of carbon immediately after treatment. However, the findings represent a point in time estimate (wildfire immediately after treatments), and a temporal analysis with a probabilistic framework used here is needed to model carbon dynamics over the life cycle of the fuel treatments. Of particular importance is the long-term balance between emissions from the decay of dead trees

The effect of test configuration on the true operating conditions of PEM fuel cells. Paper no. IGEC-1-124

International Nuclear Information System (INIS)

Simpson, T.; Li, X.

2005-01-01

The operating conditions of a single PEM fuel cell can be significantly affected by the configuration in which the fuel cell test is setup. This study investigates the effect on the gas dewpoint temperature of not insulating the inlet fittings to a PEM fuel cell and the effect of non-optimal stack control thermocouple placement on fuel cell stack operating temperature. Both of these setup configurations can significantly affect fuel cell membrane humidification conditions, especially in a single fuel cell as demonstrated through the sample test conditions presented in this paper. (author)

Influence of Fuel-Matrix Interaction on the Deformation of U-Mo Dispersion Fuel

Energy Technology Data Exchange (ETDEWEB)

Ryu, Ho Jin [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Kim, Yeon Soo [Argonne National Laboratory, Chicago (United States)

2014-05-15

In order to predict the fuel plate failure leading to breakaway swelling in the meat, an understanding of the effects of the fuel-matrix interaction behavior on the deformation of fuel meat is necessary. However, the effects of IL formation on the development of breakaway swelling have not been studied thoroughly. A mechanism that explains large pore growth that leads to breakaway swelling has not been included in the existing fuel performance models. In this study, the effect of the fuel-matrix interaction on large interfacial porosity development at the IL-Al interface is analyzed using both mechanistic correlations and observations from the post-irradiation examination results of U-Mo Dispersion fuels. The effects of fuel-matrix interaction on the fuel performance of U-Mo/Al Dispersion fuel were investigated. Fuel-matrix interaction bears the causes for breakaway swelling that can lead to a fuel failure under a high-power irradiation condition. Fission gas atoms are released from U-Mo particles to the interaction layer via diffusion and recoil. The fission gases released from the U-Mo and produced in the ILs are further released to the IL-Al interface by diffusion in the IL and recoil. Large pore formation at the IL-Al interface is attributed to the active diffusion of fission gas atoms in the ILs and coalescence between the small bubbles there. A model calculation showed that IL growth increases the probability of forming a breakaway swelling condition. ILs are connected to each other and the Al matrix decreases as ILs grow. When more ILs are interconnected, breakaway swelling can occur when the effective stress from the fission gas pressure in the IL-Al interfacial pore becomes larger than the yield strength of the Al matrix.

Effect of exhaust gas recirculation on some combustion characteristics of dual fuel engine

Energy Technology Data Exchange (ETDEWEB)

Selim, Mohamed Y.E. [United Arab Emirates Univ., Dept. of Mechanical Engineering, Al-Ain (United Arab Emirates)

2003-03-01

Combustion pressure rise rate and thermal efficiency data are measured and presented for a dual fuel engine running on a dual fuel of Diesel and compressed natural gas and utilizing exhaust gas recirculation (EGR). The maximum pressure rise rate during combustion is presented as a measure of combustion noise. The experimental investigation on the dual fuel engine revealed the noise generated from combustion and the thermal efficiency at different EGR ratios. A Ricardo E6 Diesel version engine is converted to run on a dual fuel of Diesel and compressed natural gas and having an exhaust gas recycling system is used throughout the work. The engine is fully computerized, and the cylinder pressure data and crank angle data are stored in a PC for offline analysis. The effects of EGR ratio, engine speeds, loads, temperature of recycled exhaust gases, intake charge pressure and engine compression ratio on combustion noise and thermal efficiency are examined for the dual fuel engine. The combustion noise and thermal efficiency of the dual fuel engine are found to be affected when EGR is used in the dual fuel engine. (Author)

Irradiation effects on fuels for space reactors

International Nuclear Information System (INIS)

Ranken, W.A.; Cronenberg, A.W.

1984-01-01

A review of irradiation-induced swelling and gas release experience is presented here for the three principal fuels UO 2 , UC, and UN. The primary advantage of UC and UN over UO 2 is higher thermal conductivity and attendant lower fuel temperature at equivalent pellet diameter and power density, while UO 2 offers the distinct benefit of well-known irradiation performance. Irradiation test results indicate that at equivalent burnup, temperature, and porosity conditions, UC experiences higher swelling than UO 2 or UN. Fission gas swelling becomes important at fuel temperatures above 1320 K for UC, and at somewhat higher temperatures for UO 2 and UN. Evidence exists that at equivalent fuel temperatures and burnups, high density UO 2 and UN experience comparable swelling behavior; however, differences in thermal conductivity influence overall irradiation performance. The low conductivity of UO 2 results in higher thermal gradients which contribute to fuel microcracking and gas release. As a result UO 2 exhibits higher fractional gas release than UN, at least or burnups up to about 3%

Skin toxicity of jet fuels: ultrastructural studies and the effects of substance P

International Nuclear Information System (INIS)

Monteiro-Riviere, Nancy A.; Inman, Alfred O.; Riviere, Jim E.

2004-01-01

Topical exposure to jet fuel is a significant occupational hazard. Recent studies have focused on dermal absorption of fuel and its components, or alternatively, on the biochemical or immunotoxicological sequelae to exposure. Surprisingly, morphological and ultrastructural analyses have not been systematically conducted. Similarly, few studies have compared responses in skin to that of the primary target organ, the lung. The focus of the present investigation was 2-fold: first, to characterize the ultrastructural changes seen after topical exposure to moderate doses (335 or 67 μl/cm 2 ) of jet fuels [Jet A, Jet Propellant (JP)-8, JP-8+100] for up to 4 days in pigs, and secondly, to determine if co-administration of substance P (SP) with JP-8 jet fuel in human epidermal keratinocyte cell cultures modulates toxicity as it does to pulmonary toxicity in laboratory animal studies. The primary change seen after exposure to all fuels was low-level inflammation accompanied by formation of lipid droplets in various skin layers, mitochondrial and nucleolar changes, cleft formation in the intercellular lipid lamellar bilayers, as well as disorganization in the stratum granulosum-stratum corneum interface. An increased number of Langerhans cells were also noted in jet fuel-treated skin. These changes suggest that the primary effect of jet fuel exposure is damage to the stratum corneum barrier. SP administration decreased the release of interleukin (IL)-8 normally seen in keratinocytes after JP-8 exposure, a response similar to that reported for SP's effect on JP-8 pulmonary toxicity. These studies provide a base upon which biochemical and immunological data collected in other model systems can be compared

Quantifying the effect of fuel reduction treatments on fire behavior in boreal forests

Science.gov (United States)

B.W. Butler; R.D. Ottmar; T.S. Rupp; R. Jandt; E. Miller; K. Howard; R. Schmoll; S. Theisen; R.E. Vihnanek; D. Jimenez

2013-01-01

Mechanical (e.g., shearblading) and manual (e.g., thinning) fuel treatments have become the preferred strategy of many fire managers and agencies for reducing fire hazard in boreal forests. This study attempts to characterize the effectiveness of four fuel treatments through direct measurement of fire intensity and forest floor consumption during a single prescribed...

Exhaust gas emissions from various automotive fuels for light-duty vehicles. Effects on health, environment and energy utilization

International Nuclear Information System (INIS)

Ahlvik, P.; Brandberg, Aa.

1999-12-01

The main aim of the investigation has been to assess the effects on health and environment from various alternative fuels for light-duty vehicles. Effects that can be identified and quantified, such as acidification, ozone formation, cancer risk and climate change, have been of primary interest but other effects, such as respiratory diseases, have also been investigated. Data have been collected through literature surveys for subsequent calculation of the mentioned effects in different time-frames. Corrections have been used to take into consideration the influence of climate, ageing and driving pattern. Emissions generated in fuel production have also been accounted for. The most significant and important differences between the fuels have been found for effects as ozone formation cancer risk and particulate emissions. Alternative fuels, such as methanol and methane (natural gas and biogas), significantly decrease the ozone formation in comparison to petrol, while ethanol, methanol and methane are advantageous concerning cancer risk. The particulate emissions are considerably higher for diesel engines fuelled by diesel oil and RME in comparison to the other fuels. In the future, the importance of acid emissions in the fuel production will increase since the NO x and SO x emissions will decrease from the vehicles. The emissions of climate gases could be significantly reduced by using non-fossil fuels but the efficiency of the drive train is also of importance. The technical development potential for further emission reductions is considerable for all fuels but the advantage for the best fuel options will remain in the future

Contact behavior modelling and its size effect on proton exchange membrane fuel cell

Science.gov (United States)

Qiu, Diankai; Peng, Linfa; Yi, Peiyun; Lai, Xinmin; Janßen, Holger; Lehnert, Werner

2017-10-01

Contact behavior between the gas diffusion layer (GDL) and bipolar plate (BPP) is of significant importance for proton exchange membrane fuel cells. Most current studies on contact behavior utilize experiments and finite element modelling and focus on fuel cells with graphite BPPs, which lead to high costs and huge computational requirements. The objective of this work is to build a more effective analytical method for contact behavior in fuel cells and investigate the size effect resulting from configuration alteration of channel and rib (channel/rib). Firstly, a mathematical description of channel/rib geometry is outlined in accordance with the fabrication of metallic BPP. Based on the interface deformation characteristic and Winkler surface model, contact pressure between BPP and GDL is then calculated to predict contact resistance and GDL porosity as evaluative parameters of contact behavior. Then, experiments on BPP fabrication and contact resistance measurement are conducted to validate the model. The measured results demonstrate an obvious dependence on channel/rib size. Feasibility of the model used in graphite fuel cells is also discussed. Finally, size factor is proposed for evaluating the rule of size effect. Significant increase occurs in contact resistance and porosity for higher size factor, in which channel/rib width decrease.

Repairing fuel for reinsertion

International Nuclear Information System (INIS)

Krukshenk, A.

1986-01-01

Eqiupment for nuclear reactor fuel assembly repairing produced by Westinghouse and Brawn Bovery companies is described. Repair of failed fuel assemblies replacement of defect fuel elements gives a noticeable economical effect. Thus if the cost of a new fuel assembly is 450-500 thousand dollars, the replacement of one fuel element in it costs approximately 40-60 thousand dollars. In simple cases repairing includes either removal of failed fuel elements from a fuel assembly and its reinsertion with the rest of fuel elements into the reactor core (reactor refueling), or replacement of unfailed fuel elements from one fuel assembly to a new one (fuel assembly overhaul and reconditioning)

Management of spent oxide fuel from thermal reactors: the environmental and radiological effects of alternative approaches

International Nuclear Information System (INIS)

Martin, A.; Fry, T.M.; Edmunds, J.

1983-07-01

The report presents the results of a study of the environmental and radiological effects of alternative approaches to the management of spent oxide fuel from the UK nuclear power programme. The two main alternatives are extended storage of the fuel, pending decisions on fissile material recycle, and reprocessing of the fuel commencing in the early 1990s. A review is made of experience in spent fuel storage, of the technical issues in long-term storage and of the possible needs of the UK nuclear programme. The main environmental and radiological effects of reprocessing considered in the study are the generation of radioactive wastes, the release of radioactivity in effluents with the resulting radiation exposure of the public, and occupational radiation exposure. The influence of the delay between reprocessing and fabrication of mixed oxide fuel on the environmental and radiological effects of plutonium recycle is investigated and it is shown that the effects would be minimised if reprocessing were delayed until there was a requirement for recycle. Strategies for the management of heavy elements other than plutonium are discussed and results are presented illustrating aspects of actinide management. (author)

Irradiation effects on thermal properties of LWR hydride fuel

Energy Technology Data Exchange (ETDEWEB)

Terrani, Kurt, E-mail: terrani@berkeley.edu [University of California, 4155 Etcheverry Hall, M.C. 1730, Berkeley, CA 94720-1730 (United States); Balooch, Mehdi [University of California, 4155 Etcheverry Hall, M.C. 1730, Berkeley, CA 94720-1730 (United States); Carpenter, David; Kohse, Gordon [Massachusetts Institute of Technology, 138 Albany St., Cambridge, MA 02139 (United States); Keiser, Dennis; Meyer, Mitchell [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Olander, Donald [University of California, 4155 Etcheverry Hall, M.C. 1730, Berkeley, CA 94720-1730 (United States)

2017-04-01

Three hydride mini-fuel rods were fabricated and irradiated at the MIT nuclear reactor with a maximum burnup of 0.31% FIMA or ∼5 MWd/kgU equivalent oxide fuel burnup. Fuel rods consisted of uranium-zirconium hydride (U (30 wt%)ZrH{sub 1.6}) pellets clad inside a LWR Zircaloy-2 tubing. The gap between the fuel and the cladding was filled with lead-bismuth eutectic alloy to eliminate the gas gap and the large temperature drop across it. Each mini-fuel rod was instrumented with two thermocouples with tips that are axially located halfway through the fuel centerline and cladding surface. In-pile temperature measurements enabled calculation of thermal conductivity in this fuel as a function of temperature and burnup. In-pile thermal conductivity at the beginning of test agreed well with out-of-pile measurements on unirradiated fuel and decreased rapidly with burnup.

Fuel treatment effectiveness in reducing fire intensity and spread rate - An experimental overview

Science.gov (United States)

Eric Mueller; Nicholas Skowronski; Albert Simeoni; Kenneth Clark; Robert Kremens; William Mell; Michael Gallagher; Jan Thomas; Alexander Filkov; Mohamad El Houssami; John Hom; Bret Butler

2014-01-01

Fuel treatments represent a significant component of the wildfire mitigation strategy in the United States. However, the lack of research aimed at quantifying the explicit effectiveness of fuel treatments in reducing wildfire intensity and spread rate limits our ability to make educated decisions about the type and placement of these treatments. As part of a larger...

Performance effects of coal-derived contaminants on the carbonate fuel cell

Energy Technology Data Exchange (ETDEWEB)

Pigeaud, A. [Energy Research Corp., Danbury, CT (United States); Wilemski, G. [Physical Sciences, Inc., Andover, MA (United States)

1993-05-01

Coal-derived contaminant studies have been pursued at ERC since the early 1980`s when the pace of carbonate fuel cell development began to markedly increase. Initial work was concerned with performance effects on laboratory and bench-scale carbonate fuel cells primarily due to sulfur compounds. Results have now also been obtained with respect to nine additional coal-gas contaminants, including volatile trace metal species. Thermochemical calculations, out-of-cell experiments, and cell performance as well as endurance testshave recently been conducted which have involved the following species: NH{sub 3}, H{sub 2}S [COS], HCl, AsH{sub 3}[As{sub 2}(v)], Zn(v), Pb(v), Cd(v), H{sub 2} Se, Hg(v), Sn(v). Employing thermochemically calculated results, thermogravimetric (TGA) and pre-, and post-test analytical data as well as fuel cell performance observations, it has been shown that there are four main mechanisms of contaminant interaction with the carbonate fuel cell. These have been formulated into performance models for six significant contaminant species, thus providing long-term endurance estimations.

Performance effects of coal-derived contaminants on the carbonate fuel cell

Energy Technology Data Exchange (ETDEWEB)

Pigeaud, A. (Energy Research Corp., Danbury, CT (United States)); Wilemski, G. (Physical Sciences, Inc., Andover, MA (United States))

1993-01-01

Coal-derived contaminant studies have been pursued at ERC since the early 1980's when the pace of carbonate fuel cell development began to markedly increase. Initial work was concerned with performance effects on laboratory and bench-scale carbonate fuel cells primarily due to sulfur compounds. Results have now also been obtained with respect to nine additional coal-gas contaminants, including volatile trace metal species. Thermochemical calculations, out-of-cell experiments, and cell performance as well as endurance testshave recently been conducted which have involved the following species: NH[sub 3], H[sub 2]S [COS], HCl, AsH[sub 3][As[sub 2](v)], Zn(v), Pb(v), Cd(v), H[sub 2] Se, Hg(v), Sn(v). Employing thermochemically calculated results, thermogravimetric (TGA) and pre-, and post-test analytical data as well as fuel cell performance observations, it has been shown that there are four main mechanisms of contaminant interaction with the carbonate fuel cell. These have been formulated into performance models for six significant contaminant species, thus providing long-term endurance estimations.

Effect of stress evolution on microstructural behavior in U-Mo/Al dispersion fuel

Energy Technology Data Exchange (ETDEWEB)

Jeong, G.Y. [Department of Nuclear Engineering, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Kim, Yeon Soo; Jamison, L.M. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Robinson, A.B. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States); Lee, K.H. [Korea Atomic Energy Research Institute, 989-111 Daedeokdaero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Sohn, Dong-Seong, E-mail: dssohn@unist.ac.kr [Department of Nuclear Engineering, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of)

2017-04-15

U-Mo/Al dispersion fuel irradiated to high burnup at high power (high fission rate) exhibited microstructural changes including deformation of the fuel particles, pore growth, and rupture of the Al matrix. The driving force for these microstructural changes was meat swelling resulting from a combination of fuel particle swelling and interaction layer (IL) growth. In some cases, pore growth in the interaction layers also contributed to meat swelling. The main objective of this work was to determine the stress distribution within the fuel meat that caused these phenomena. A mechanical equilibrium between the stress generated by fuel meat swelling and the stress relieved by fission-induced creep in the meat constituents (U-Mo particles, Al matrix, and IL) was considered. Test plates with well-recorded fabrication data and irradiation conditions were used, and their post-irradiation examination (PIE) data was obtained. ABAQUS finite element analysis (FEA) was utilized to simulate the microstructural evolution of the plates. The simulation results allowed for the determination of effective stress and hydrostatic stress exerted on the meat constituents. The effects of fabrication and irradiation parameters on the stress distribution that drives microstructural evolutions, such as pore growth in the IL and Al matrix rupture, were investigated. - Highlights: •Post-irradiation data for irradiated miniplates were analyzed by using their optical microscopy images. •ABAQUS finite element analysis (FEA) package was utilized to simulate the microstructural evolution of the selected plates. •Stresses were assessed to analyze their effects on microstructural changes during irradiation.

Quantifying physical characteristics of wildland fuels using the fuel characteristic classification system.

Science.gov (United States)

Cynthia L. Riccardi; Susan J. Prichard; David V. Sandberg; Roger D. Ottmar

2007-01-01

Wildland fuel characteristics are used in many applications of operational fire predictions and to understand fire effects and behaviour. Even so, there is a shortage of information on basic fuel properties and the physical characteristics of wildland fuels. The Fuel Characteristic Classification System (FCCS) builds and catalogues fuelbed descriptions based on...

Review on Fuel Loading Process and Performance for Advanced Fuel Handling Equipment

International Nuclear Information System (INIS)

Chang, Sang-Gyoon; Lee, Dae-Hee; Kim, Young-Baik; Lee, Deuck-Soo

2007-01-01

The fuel loading process and the performance of the advanced fuel handling equipment for OPR 1000 (Optimized Power Plant) are analyzed and evaluated. The fuel handling equipment, which acts critical processes in the refueling outage, has been improved to reduce fuel handling time. The analysis of the fuel loading process can be a useful tool to improve the performance of the fuel handling equipment effectively. Some recommendations for further improvement are provided based on this study

Numerical and experimental investigation on effects of inlet humidity and fuel flow rate and oxidant on the performance on polymer fuel cell

International Nuclear Information System (INIS)

Takalloo, Pourya Karimi; Nia, Ehsan Shabahang; Ghazikhani, Mohsen

2016-01-01

Highlights: • The impact of alteration in humidification on performance of fuel cell. • The impact of variation of temperature on performance of fuel cell. • The effects of using pure oxygen on the polarity curve are studied. • Fuel cell has been investigated both experimentally and numerically. - Abstract: Considering the importance of water management in a fuel cell and in order to increase the rate of the electro-chemical process in fuel cells with polymer membrane, it is required to optimize the humidity and inlet flow rates on anode and cathode sides. In this study, the impact of alteration in humidification and inlet flow rates on performance improvements for polymer membrane fuel cells is investigated both experimentally and numerically. To obtain the objective, employing the results from experiments and simulations, polarity curve and power density are produced and further used to conduct the desired investigations. In addition, through the conducted simulations the effects of using pure oxygen in the cathode side and inlet gas temperatures on the polarity curve is studied. The results demonstrate that an increase in humidity of the inlet gases will lead to performance amelioration in the cell, due to reduction in ionic resistance at the membrane. Furthermore, with the aforementioned increment; molar fractions of hydrogen and oxygen are decreased through the channel which results in produced water increment. Amplification in inlet flow rates to a certain level will improve the penetration possibility for gaseous forms leading to betterment of the cell performance in this specified range. Performance improvements with inlet gases temperature increment conclude other results of this study.

Reduced enrichment fuel and its reactivity effects in the University Training Reactor Moata

International Nuclear Information System (INIS)

Wilson, D.J.

1983-08-01

Concern for nuclear proliferation is likely to preclude future supply of highly enriched uranium fuel for research reactors such as the University Training Reactor Moata. This study calculates the fuel densities necessary to maintain the reactivity per plate of the present high enrichment (90 per cent 235 U) fuel for a range of lower enrichments assuming that no geometry changes are allowed. The maximum uranium density for commercially available aluminium-type research reactor fuels is generally considered to be about 1.7 g cm -3 . With this density limitation, the minimum enrichment to maintain present reactivity per plate is about 35 per cent 235 U. For low enrichment (max. 20 per cent 235 U) fuel, the required U density is about 2.9 g cm -3 , which is beyond the expected range for UAl/sub x/-Al but within that projected for the longer term development and full qualification for U 3 O 8 -Al. Medium enrichment (nominally 45 per cent 235 U) Al/sub x/-Al would be entirely satisfactory as an immediate replacement fuel, requiring no modifications to the reactor and operating procedures, and minimal reappraisal of safety issues. Included in this study are calculations of the fuel coefficients at various enrichments, the effect of replacing standard fuel plates or complete elements with 45 per cent enriched fuel, and the reactivity to be gained by replacing 12-plate with 13-plate elements

Effect of cracks in coating on gas release from a fuel microparticle

International Nuclear Information System (INIS)

Bondarenko, A.G.; Gudkov, A.N.; Tselishchev, Yu.V.

1988-01-01

Effect of cracks in protective coating on gas release from a fuel microparticle is investigated in a general form. A fuel microparticle comprizing a kern, a buffer layer and an external protective coating is considered. The pressure of radioactive inert gases in the microparticle buffer layer is evaluated within the 1000-1800 K temperature range on the base of diffusion-defect-trap transport theory. It is shown that the process of radionuclide adsorption interaction with the coating material leads to a more abrupt than by exponent, weakening of mass transfer coefficient. In this case for long-living isotopes the effect of adsorption processes manifests weaker than for short-living ones. Mass transfer coefficient for the crack system depends sufficiently on the total pressure of gas mixture under the coating while for a single cracks such dependence is not observed. A conclusion is drawn that the obtained ratios can be applied for evaluating the character of fuel microparticle protective coating destruction (single non-intersecting cracks or a crack system) using the data on various nuclide release. These ratios can be also applied for the choice of the coating thichness under which gaseous fission product release from the fuel microparticle in case of its protective coating failure does not exceed the acceptable limits

Global warming and urban smog: The cost effectiveness of CAFE standards and alternative fuels

International Nuclear Information System (INIS)

Krupnick, A.J.; Walls, M.A.; Collins, C.T.

1992-01-01

This paper evaluates alternative transportation policies for reducing greenhouse gas emissions and ozone precursors. The net cost-effectiveness -- i.e., the cost per ton of greenhouse gas reduced, adjusted for ozone reduction benefits -- of substituting methanol, compressed natural gas (CNG), and reformulated gasoline for conventional gasoline is assessed and compared with the cost-effectiveness of raising the corporate average fuel economy (CAFE) standard to 38 miles per gallon. Computing this open-quotes netclose quotes cost-effectiveness is one way of measuring the joint environmental benefits that these alternatives provide. Greenhouse gas emissions are assessed over the entire fuel cycle and include not only carbon dioxide emissions, but also methane, carbon monoxide, and nitrous oxide emissions. In computing cost-effectiveness, we account for the so-called open-quotes rebound effectclose quotes -- the impact on vehicle-miles traveled of higher or lower fuel costs. CNG is found to be the most cost-effective of these alternatives, followed by increasing the CAFE standard, substituting methanol for gasoline, and substituting reformulated for conventional gasoline. Including the ozone reduction benefits does not change the rankings of the alternatives, but does make the alternative fuels look better relative to increasing the CAFE standard. Incorporating the rebound effect greatly changes the magnitude of the estimates but does not change the rankings of the alternatives. None of the alternatives look cost-effective should a carbon tax of $35 per ton be passes (the proposal in the Stark bill, H.R. 1086), and only CNG under optimistic assumptions looks cost-effective if a tax of $100 per ton of carbon is passed

Effects of ethylene glycol ethers on diesel fuel properties and emissions in a diesel engine

Energy Technology Data Exchange (ETDEWEB)

Gomez-Cuenca, F.; Gomez-Marin, M. [Compania Logistica de Hidrocarburos (CLH), Central Laboratory, Mendez Alvaro 44, 28045 Madrid (Spain); Folgueras-Diaz, M.B., E-mail: belenfd@uniovi.es [Department of Energy, University of Oviedo, Independencia 13, 33004 Oviedo (Spain)

2011-08-15

Highlights: {yields} Effect of ethylene glycol ethers on diesel fuel properties. {yields} Effect of ethylene glycol ethers on diesel engine specific consumption and emissions. {yields} Blends with {<=}4 wt.% of oxygen do not change substantially diesel fuel quality. {yields} Blends with 1 and 2.5 wt.% of oxygen reduce CO and HC emissions, but not smoke. - Abstract: The effect of ethylene glycol ethers on both the diesel fuel characteristics and the exhaust emissions (CO, NO{sub x}, smoke and hydrocarbons) from a diesel engine was studied. The ethers used were monoethylene glycol ethyl ether (EGEE), monoethylene glycol butyl ether (EGBE), diethylene glycol ethyl ether (DEGEE). The above effect was studied in two forms: first by determining the modification of base diesel fuel properties by using blends with oxygen concentration around 4 wt.%, and second by determining the emission reductions for blends with low oxygen content (1 wt.%) and with 2.5 wt.% of oxygen content. The addition of DEGEE enhances base diesel fuel cetane number, but EGEE and EGBE decrease it. For concentrations of {>=}4 wt.% of oxygen, EGEE and diesel fuel can show immiscibility problems at low temperatures ({<=}0 {sup o}C). Also, every oxygenated compound, according to its boiling point, modifies the distillation curve at low temperatures and the distillate percentage increases. These compounds have a positive effect on diesel fuel lubricity, and slightly decrease its viscosity. Blends with 1 and 2.5 wt.% oxygen concentrations were used in order to determine their influence on emissions at both full and medium loads and different engine speeds. Generally, all compounds help to reduce CO, and hydrocarbon emissions, but not smoke. The best results were obtained for blends with 2.5 wt.% of oxygen. At this concentration, the additive efficiency in decreasing order was EGEE > DEGEE > EGBE for CO emissions and DGEE > EGEE > EGBE for hydrocarbon emissions. For NO{sub x}, both its behaviour and the

Fuel assembly

International Nuclear Information System (INIS)

Ueda, Makoto; Ogiya, Shunsuke.

1989-01-01

For improving the economy of a BWR type reactor by making the operation cycle longer, the fuel enrichment degree has to be increased further. However, this makes the subcriticality shallower in the upper portion of the reactor core, to bring about a possibility that the reactor shutdown becomes impossible. In the present invention, a portion of fuel rod is constituted as partial length fuel rods (P-fuel rods) in which the entire stack length in the effective portion is made shorter by reducing the concentration of fissionable materials in the axial portion. A plurality of moderator rods are disposed at least on one diagonal line of a fuel assembly and P-fuel rods are arranged at a position put between the moderator rods. This makes it possible to reactor shutdown and makes the axial power distribution satisfactory even if the fuel enrichment degree is increased. (T.M.)

High density fuels using dispersion and monolithic fuel

Energy Technology Data Exchange (ETDEWEB)

Gomes, Daniel S.; Silva, Antonio T.; Abe, Alfredo Y.; Muniz, Rafael O.R.; Giovedi, Claudia, E-mail: dsgomes@ipen.br, E-mail: teixeira@ipen.br, E-mail: alfredo@ctmsp.mar.mil.br, E-mail: rafael.orm@gmail.com, E-mail: claudia.giovedi@ctmsp.mar.mil.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Universidade de São Paulo (USP), SP (Brazil). Departamento de Engenharia Naval e Oceânica

2017-07-01

Fuel plates used in high-performance research reactors need to be converted to low-enrichment uranium fuel; the fuel option based on a monolithic formulation requires alloys to contain 6 - 10 wt% Mo. In this case, the fuel plates are composed of the metallic alloy U-10Mo surrounded by a thin zirconium layer encapsulated in aluminum cladding. This study reviewed the physical properties of monolithic forms. The constraints produced during the manufacturing process were analyzed and compared to those of dispersed fuel. The bonding process used for dispersion fuels differs from the techniques applied to foil bonding used for pure alloys. The quality of monolithic plates depends on the fabrication method, which usually involves hot isostatic pressing and the thermal annealing effect of residual stress, which degrades the uranium cubic phase. The preservation of the metastable phase has considerable influence on fuel performance. The physical properties of the foil fuel under irradiation are superior to those of aluminum-dispersed fuels. The fuel meat, using zirconium as the diffusion barrier, prevents the interaction layer from becoming excessively thick. The problem with dispersed fuel is breakaway swelling with a medium fission rate. It has been observed that the fuel dispersed in aluminum was minimized in monolithic forms. The pure alloys exhibited a suitable response from a rate at least twice as much as the fission rate of dispersions. The foils can support fissile material concentration combined with a reduced swelling rate. (author)

High density fuels using dispersion and monolithic fuel

International Nuclear Information System (INIS)

Gomes, Daniel S.; Silva, Antonio T.; Abe, Alfredo Y.; Muniz, Rafael O.R.; Giovedi, Claudia; Universidade de São Paulo

2017-01-01

Fuel plates used in high-performance research reactors need to be converted to low-enrichment uranium fuel; the fuel option based on a monolithic formulation requires alloys to contain 6 - 10 wt% Mo. In this case, the fuel plates are composed of the metallic alloy U-10Mo surrounded by a thin zirconium layer encapsulated in aluminum cladding. This study reviewed the physical properties of monolithic forms. The constraints produced during the manufacturing process were analyzed and compared to those of dispersed fuel. The bonding process used for dispersion fuels differs from the techniques applied to foil bonding used for pure alloys. The quality of monolithic plates depends on the fabrication method, which usually involves hot isostatic pressing and the thermal annealing effect of residual stress, which degrades the uranium cubic phase. The preservation of the metastable phase has considerable influence on fuel performance. The physical properties of the foil fuel under irradiation are superior to those of aluminum-dispersed fuels. The fuel meat, using zirconium as the diffusion barrier, prevents the interaction layer from becoming excessively thick. The problem with dispersed fuel is breakaway swelling with a medium fission rate. It has been observed that the fuel dispersed in aluminum was minimized in monolithic forms. The pure alloys exhibited a suitable response from a rate at least twice as much as the fission rate of dispersions. The foils can support fissile material concentration combined with a reduced swelling rate. (author)

Fuel assembly

International Nuclear Information System (INIS)

Bando, Masaru.

1993-01-01

As neutron irradiation progresses on a fuel assembly of an FBR type reactor, a strong force is exerted to cause ruptures if the arrangement of fuel elements is not displaced, whereas the fuel elements may be brought into direct contact with each other not by way of spacers to cause burning damages if the arrangement is displaced. In the present invention, the circumference of fuel elements arranged in a normal triangle lattice is surrounded by a wrapper tube having a hexagonal cross section, wire spacers are wound therearound, and deformable spacers are distributed to optional positions for fuel elements in the wrapper tube. Interaction between the fuel elements caused by irradiation is effectively absorbed, thereby enabling to delay the occurrence of the rupture and burning damages of the elements. (N.H.)

Estimating the effect of urban density on fuel demand

Energy Technology Data Exchange (ETDEWEB)

Karathodorou, Niovi; Graham, Daniel J. [Imperial College London, London, SW7 2AZ (United Kingdom); Noland, Robert B. [Rutgers University, New Brunswick, NJ 08901 (United States)

2010-01-15

Much of the empirical literature on fuel demand presents estimates derived from national data which do not permit any explicit consideration of the spatial structure of the economy. Intuitively we would expect the degree of spatial concentration of activities to have a strong link with transport fuel consumption. The present paper addresses this theme by estimating a fuel demand model for urban areas to provide a direct estimate of the elasticity of demand with respect to urban density. Fuel demand per capita is decomposed into car stock per capita, fuel consumption per kilometre and annual distance driven per car per year. Urban density is found to affect fuel consumption, mostly through variations in the car stock and in the distances travelled, rather than through fuel consumption per kilometre. (author)

Fuel effects on the stability of turbulent flames with compositionally inhomogeneous inlets

KAUST Repository

Guiberti, T. F.

2016-10-11

This paper reports an analysis of the influence of fuels on the stabilization of turbulent piloted jet flames with inhomogeneous inlets. The burner is identical to that used earlier by the Sydney Group and employs two concentric tubes within the pilot stream. The inner tube, carrying fuel, can be recessed, leading to a varying degree of inhomogeneity in mixing with the outer air stream. Three fuels are tested: dimethyl ether (DME), liquefied petroleum gas (LPG), and compressed natural gas (CNG). It is found that improvement in flame stability at the optimal compositional inhomogeneity is highest for CNG and lowest for DME. Three possible reasons for this different enhancement in stability are investigated: mixing patterns, pilot effects, and fuel chemistry. Numerical simulations realized in the injection tube highlight similarities and differences in the mixing patterns for all three fuels and demonstrate that mixing cannot explain the different stability gains. Changing the heat release rates from the pilot affects the three fuels in similar ways and this also implies that the pilot stream is unlikely to be responsible for the observed differences. Fuel reactivity is identified as a key factor in enhancing stability at some optimal compositional inhomogeneity. This is confirmed by inference from joint images of PLIF-OH and PLIF-CHO, collected at a repetition rate of 10kHz in turbulent flames of DME, and from one-dimensional calculations of laminar flames using detailed chemistry for DME, CNG, and LPG.

Effect of reference parameters and properties of materials for WWER-type fuel elements on their reliability

Energy Technology Data Exchange (ETDEWEB)

Bibilashvili, Yu K; Malachenko, L L; Medvedev, A V; Solyany, V I; Sukhanov, G I; Tonkov, V Yu

1987-05-01

Present approach to requirements for reference parameters and properties of materials for WWER-1000 fuel elements is presented as well as evaluation of their effects on fuel reliability. Some results of investigations with the aim of improving fuel element reliability in operational NPP conditions are discussed. 4 references, 7 figures, 3 tables.

Effect of unequal fuel and oxidizer Lewis numbers on flame dynamics

Energy Technology Data Exchange (ETDEWEB)

Shamim, Tariq [Department of Mechanical Engineering, The University of Michigan-Dearborn, Dearborn, MI 48128-1491 (United States)

2006-12-15

The interaction of non-unity Lewis number (due to preferential diffusion and/or unequal rates of heat and mass transfer) with the coupled effect of radiation, chemistry and unsteadiness alters several characteristics of a flame. The present study numerically investigates this interaction with a particular emphasis on the effect of unequal and non-unity fuel and oxidizer Lewis numbers in a transient diffusion flame. The unsteadiness is simulated by considering the flame subjected to modulations in reactant concentration. Flames with different Lewis numbers (ranging from 0.5 to 2) and subjected to different modulating frequencies are considered. The results show that the coupled effect of Lewis number and unsteadiness strongly influences the flame dynamics. The impact is stronger at high modulating frequencies and strain rates, particularly for large values of Lewis numbers. Compared to the oxidizer side Lewis number, the fuel side Lewis number has greater influence on flame dynamics. (author)

Distributional effects of taxing transport fuel

International Nuclear Information System (INIS)

Sterner, Thomas

2012-01-01

This paper takes as its starting point the observation that fuel prices – and thus taxes – are important for good management of climate change and other environmental problems. To economists this should be no surprise yet it seems that the role of fuel taxation as an instrument of climate policy has not been fully appreciated. It is however one of the few policy instruments that, since several decades, has actually reduced fuel consumption appreciably. Thanks to taxation (mainly in Europe and Japan), carbon emissions are considerably lower than they would have been otherwise. In future where carbon emissions are to be cut drastically, this instrument will be crucial. There is however much opposition to the instrument. This opposition uses various arguments, for instance that fuel taxes hurt the poor since they are strongly regressive. We however find that the choice of country and methodology turns out to be of great consequence. We study seven European countries—France, Germany, United Kingdom, Italy, Serbia, Spain and Sweden and do find some evidence of regressivity but the evidence is very weak. It does not apply when lifetime income is used and it does not apply to the poorest country in the group. The best one-line summary is probably that the tax is approximately proportional.

Integration of the AVLIS (atomic vapor laser isotopic separation) process into the nuclear fuel cycle. [Effect of AVLIS feed requirements on overall fuel cycle

Energy Technology Data Exchange (ETDEWEB)

Hargrove, R.S.; Knighton, J.B.; Eby, R.S.; Pashley, J.H.; Norman, R.E.

1986-08-01

AVLIS RD and D efforts are currently proceeding toward full-scale integrated enrichment demonstrations in the late 1980's and potential plant deployment in the mid 1990's. Since AVLIS requires a uranium metal feed and produces an enriched uranium metal product, some change in current uranium processing practices are necessitated. AVLIS could operate with a UF/sub 6/-in UF/sub 6/-out interface with little effect to the remainder of the fuel cycle. This path, however, does not allow electric utility customers to realize the full potential of low cost AVLIS enrichment. Several alternative processing methods have been identified and evaluated which appear to provide opportunities to make substantial cost savings in the overall fuel cycle. These alternatives involve varying levels of RD and D resources, calendar time, and technical risk to implement and provide these cost reduction opportunities. Both feed conversion contracts and fuel fabricator contracts are long-term entities. Because of these factors, it is not too early to start planning and making decisions on the most advantageous options so that AVLIS can be integrated cost effectively into the fuel cycle. This should offer economic opportunity to all parties involved including DOE, utilities, feed converters, and fuel fabricators. 10 refs., 11 figs., 2 tabs.

Fuel substitution - poverty impacts on biomass fuel suppliers (Uganda, Kenya and Ethiopia)

International Nuclear Information System (INIS)

2002-01-01

Many sub Saharan countries view the increasing use of traditional fuels (primarily charcoal and, to a lesser extent, wood) in urban areas as a major cause of environmental degradation. Governments are concerned about the effects of perceived rising costs of traditional fuels on poor households and seek to reduce those costs. Many are also concerned with the health impacts that using traditional fuels may have in households. In response to this, many governments have prompted a shift from traditional fuels for cooking to kerosene, gas and electricity as substitutes, and to energy-efficient charcoal and wood stoves to reduce these impacts. Such interventions can have major impacts on the livelihoods of people engaged in the production, transport and sale of traditional biomass supplies due to the decline in demand for wood-based fuels. This project will quantify the impact that fuel substitution will have on people engaged in traditional fuel supply, distribution and trade and develop a set of recommendations for Kenya, Ethiopia and Uganda that will recommend ways to mitigate the negative effects of fuel substitution on traditional biomass fuel suppliers. At the same time, it will address how this can be accomplished while mitigating the environmental and health impacts of continued use of traditional fuels. (author)

Fuel substitution - poverty impacts on biomass fuel suppliers (Uganda, Kenya and Ethiopia)

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-07-01

Many sub Saharan countries view the increasing use of traditional fuels (primarily charcoal and, to a lesser extent, wood) in urban areas as a major cause of environmental degradation. Governments are concerned about the effects of perceived rising costs of traditional fuels on poor households and seek to reduce those costs. Many are also concerned with the health impacts that using traditional fuels may have in households. In response to this, many governments have prompted a shift from traditional fuels for cooking to kerosene, gas and electricity as substitutes, and to energy-efficient charcoal and wood stoves to reduce these impacts. Such interventions can have major impacts on the livelihoods of people engaged in the production, transport and sale of traditional biomass supplies due to the decline in demand for wood-based fuels. This project will quantify the impact that fuel substitution will have on people engaged in traditional fuel supply, distribution and trade and develop a set of recommendations for Kenya, Ethiopia and Uganda that will recommend ways to mitigate the negative effects of fuel substitution on traditional biomass fuel suppliers. At the same time, it will address how this can be accomplished while mitigating the environmental and health impacts of continued use of traditional fuels. (author)

Effect of Granule Size on Diametric Tolerance of Annular Fuel Pellet

International Nuclear Information System (INIS)

Rhee, Young Woo; Kim, Dong Joo; Kim, Jong Hun; Yang, Jae Ho; Kim, Keon Sik; Kang, Ki Won; Song, Kun Woo

2008-01-01

A dual cooled annular fuel has been seriously considered as a favorable option for an extended power uprate of a Pressurized Water Reactor fuel assembly. An annular fuel shows a lot of advantages from the point of a fuel safety and its economy due to its unique configurational merit such as an increased heat transfer area and a thin pellet thickness. From the viewpoint of the fuel pellet fabrication, however, the unique shape of annular fuel pellet causes challenging difficulties to satisfy a diametric tolerance. A sintered cylindrical PWR fuel pellet fabricated by a conventional double-acting press has an hour-glass shape due to an inhomogeneous green density distribution in a powder compact. Thus, a sintered pellet usually undergoes a centerless grinding process in order to secure diametric tolerance specifications. In the case of an annular pellet fabrication using a conventional double-acting press, the same hour-glass shape would probably occur. An inhomogeneous green density distribution in a powder compact is attributed to granule-granule frictions and granule to pressing mold wall frictions. Frictions result in an irregular pressing load distribution in a powder compact. In order to mitigate the frictions, a lot of process variables should be considered such as pre-compaction pressure, lubricant content, granule size and compaction pressure. The purpose of this study is to investigate the effect of a granule size on the amount of deformation after sintering, in other words, the amount of an hour-glassing. The granules with classified size ranges were made to green annular pellets with the same height and diameters. The hour-glassing amounts of the sintered annular pellets were measured and compared with that of the annular pellet made by unclassified granule

Alternative-Fuel Effects on Contrails & Cruise Emissions (ACCESS-2) Flight Experiment

Science.gov (United States)

Anderson, Bruce E.

2015-01-01

Although the emission performance of gas-turbine engines burning renewable aviation fuels have been thoroughly documented in recent ground-based studies, there is still great uncertainty regarding how the fuels effect aircraft exhaust composition and contrail formation at cruise altitudes. To fill this information gap, the NASA Aeronautics Research Mission Directorate sponsored the ACCESS flight series to make detailed measurements of trace gases, aerosols and ice particles in the near-field behind the NASA DC-8 aircraft as it burned either standard petroleum-based fuel of varying sulfur content or a 50:50 blend of standard fuel and a hydro-treated esters and fatty acid (HEFA) jet fuel produced from camelina plant oil. ACCESS 1, conducted in spring 2013 near Palmdale CA, focused on refining flight plans and sampling techniques and used the instrumented NASA Langley HU-25 aircraft to document DC-8 emissions and contrails on five separate flights of approx.2 hour duration. ACCESS 2, conducted from Palmdale in May 2014, engaged partners from the Deutsches Zentrum fuer Luft- und Raumfahrt (DLR) and National Research Council-Canada to provide additional scientific expertise and sampling aircraft (Falcon 20 and CT-133, respectively) with more extensive trace gas, particle, or air motion measurement capability. Eight, muliti-aircraft research flights of 2 to 4 hour duration were conducted to document the emissions and contrail properties of the DC-8 as it 1) burned low sulfur Jet A, high sulfur Jet A or low sulfur Jet A/HEFA blend, 2) flew at altitudes between 6 and 11 km, and 3) operated its engines at three different fuel flow rates. This presentation further describes the ACCESS flight experiments, examines fuel type and thrust setting impacts on engine emissions, and compares cruise-altitude observations with similar data acquired in ground tests.

Investigation of microalgae HTL fuel effects on diesel engine performance and exhaust emissions using surrogate fuels

International Nuclear Information System (INIS)

Hossain, Farhad M.; Nabi, Md. Nurun; Rainey, Thomas J.; Bodisco, Timothy; Rahman, Md. Mostafizur; Suara, Kabir; Rahman, S.M.A.; Van, Thuy Chu; Ristovski, Zoran; Brown, Richard J.

2017-01-01

Highlights: • Development of a microalgae HTL surrogate of biocrude fuel using chemical compounds. • Physiochemical properties of surrogate blends were analysed. • Experimentally investigated diesel engine performance and emissions using surrogate fuels. • No significant changes in engine performance were observed with HTL surrogate blends. • Major emissions including PM, PN and CO were reduced significantly with increasing of NOx emission. - Abstract: This paper builds on previous work using surrogate fuel to investigate advanced internal combustion engine fuels. To date, a surrogate fuel of this nature has not been used for microalgae hydrothermal liquefaction (HTL) biocrude. This research used five different chemical groups found in microalgae HTL biocrude to design a surrogate fuel. Those five chemical groups constitute around 65% (by weight) of a microalgae biocrude produced by HTL. Weight percentage of the microalgae HTL biocrude chemical compounds were used to design the surrogate fuel, which was miscible with diesel at all percentages. The engine experiments were conducted on a EURO IIIA turbocharged common-rail direct-injection six-cylinder diesel engine to test engine performance and emissions. Exhaust emissions, including particulate matter and other gaseous emissions, were measured with the surrogate fuel and a reference diesel fuel. Experimental results showed that without significantly deteriorating engine performance, lower particulate mass, particulate number and CO emissions were observed with a penalty in NOx emissions for all surrogate blends compared to those of the reference diesel.

Reforming petroleum-based fuels for fuel cell vehicles : composition-performance relationships

International Nuclear Information System (INIS)

Kopasz, J. P.; Miller, L. E.; Ahmed, S.; Devlin, P. R.; Pacheco, M.

2001-01-01

Onboard reforming of petroleum-based fuels, such as gasoline, may help ease the introduction of fuel cell vehicles to the marketplace. Although gasoline can be reformed, it is optimized to meet the demands of ICEs. This optimization includes blending to increase the octane number and addition of oxygenates and detergents to control emissions. The requirements for a fuel for onboard reforming to hydrogen are quite different than those for combustion. Factors such as octane number and flame speed are not important; however, factors such as hydrogen density, catalyst-fuel interactions, and possible catalyst poisoning become paramount. In order to identify what factors are important in a hydrocarbon fuel for reforming to hydrogen and what factors are detrimental, we have begun a program to test various components of gasoline and blends of components under autothermal reforming conditions. The results indicate that fuel composition can have a large effect on reforming behavior. Components which may be beneficial for ICEs for their octane enhancing value were detrimental to reforming. Fuels with high aromatic and naphthenic content were more difficult to reform. Aromatics were also found to have an impact on the kinetics for reforming of paraffins. The effects of sulfur impurities were dependent on the catalyst. Sulfur was detrimental for Ni, Co, and Ru catalysts. Sulfur was beneficial for reforming with Pt catalysts, however, the effect was dependent on the sulfur concentration

Fuel composition effect on the electrostatically-driven atomization of bio-butanol containing engine fuel blends

International Nuclear Information System (INIS)

Agathou, Maria S.; Kyritsis, Dimitrios C.

2012-01-01

Highlights: ► Sprays of alcohol-containing blends are amenable to electrostatic manipulation. ► Monodispersion is non-achievable for conditions pertaining to automotive applications. ► Electrical conductivity and surface tension do not determine fully the spray behavior. ► Non-dimensional analysis was performed to classify flow regimes for each blend. ► We numbers revealed the possibility of droplet secondary break-up. - Abstract: Electrostatically assisted sprays of three fuel blends of bio-butanol, ethanol and heptane were studied experimentally. Mixture composition was selected such that electrical conductivity and surface tension were kept constant for all three mixtures. In this manner, the effect of fuel composition was investigated in a context that broadens the classical focus on the effective decrease of surface tension through the action of electrostatic fields. High-speed visualization was used in order to capture e-spray morphology. In addition, probability density functions of the e-spray droplet size and velocity were measured using Phase-Doppler Anemometry for a variety of flow rates and applied voltages. The dependence of droplet average diameter on both flow rate and applied electric field was highlighted. Polydisperse sprays were observed which was rationalized through the calculation of droplet Weber numbers that pointed to the possibility of a secondary droplet break-up.

Global warming and urban smog: Cost-effectiveness of CAFE standards and alternative fuels

International Nuclear Information System (INIS)

Krupnick, A.J.; Walls, M.A.; Collins, C.T.

1993-01-01

In this paper we estimate the cost-effectiveness, in terms of reducing greenhouse gas emissions, of increasing the corporate average fuel economy (CAFE) standard to 38 miles per gallon and substituting methanol, compressed natural gas (CNG), and reformulated gasoline for conventional gasoline. Greenhouse gas emissions are assessed over the entire fuel cycle and include carbon dioxide, methane, carbon monoxide, and nitrous oxide emissions. To account for joint environmental benefits, the cost per ton of greenhouse gas reduced is adjusted for reductions in volatile organic compound (VOC) emissions, an ozone precursor. CNG is found to be the most cost-effective of these alternatives, followed by increasing the CAFE standard, substituting methanol for gasoline, and substituting reformulated for conventional gasoline. Including the VOC benefits does not change the ranking of the alternatives, but does make the alternative fuels look better relative to increasing the CAFE standard. None of the alternatives look cost-effective should a carbon tax of $35 per ton be passed, and only CNG under optimistic assumptions looks cost-effective with a tax of $100 per ton of carbon. 35 refs., 4 figs., 6 tabs

Containing method for spent fuel and spent fuel containing vessel

International Nuclear Information System (INIS)

Maekawa, Hiromichi; Hanada, Yoshine.

1996-01-01

Upon containing spent fuels, a metal vessel main body and a support spacer having fuel containing holes are provided. The support spacer is disposed in the inside of the metal vessel main body, and spent fuel assemblies are loaded in the fuel containing holes. Then, a lid is welded at the opening of the metal vessel main body to provide a sealing state. In this state, heat released from the spent fuel assemblies is transferred to the wall of the metal vessel main body via the support spacer. Since the support spacer has a greater heat conductivity than gases, heat of the spent fuel assemblies tends to be released to the outside, thereby capable of removing heat of the spent fuel assemblies effectively. In addition, since the surfaces of the spent fuel assemblies are in contact with the inner surface of the fuel containing holes of the support spacer, impact-resistance and earthquake-resistance are ensured, and radiation from the spent fuel assemblies is decayed by passing through the layer of the support spacer. (T.M.)

An automatic procedure for optimizing fuel loading in consideration of the effect of burnup nonuniformity in assembly

International Nuclear Information System (INIS)

Wang Guoli.

1988-01-01

The effect of burnup nonuniformity across the assembly on optimizing fuel loading in core is investigated. Some new rules which can be used for optimizing fuel loading in the core are proposed. New automatic procedure for optimizing fuel loading in the core is described

Effects of consumer subsidy on household fuel switching from coal to cleaner fuels: A case study for anthracites in Korea

International Nuclear Information System (INIS)

Park, Hojeong; Kwon, Hyucksoo

2011-01-01

The Korean coal industry is in a transition under low carbon policy through the steady reduction of coal production. Since consumer subsidy for the consumption of anthracites briquette in low-income households caused a distortion in domestic coal market, the so-called coupon program will be the first target in energy reform policy in order to induce fuel switching from anthracites to alternative clean energy. This paper tries to identify various factors that influence households' fuel switching decision. Disutility from briquette consumption is also considered as an important factor. Using the 2007 census data on briquette-consuming households, it is found that the coupon program provides an adverse effect to switching fuels to clean energy while the disutility of briquettes is positively associated with the probability of fuel switching. However, the empirical finding suggests that the policy alone attempting to remove coupon program may fail to switch fuels unless the cost of boiler changes is substantially reduced through the provision of accessible networks to alternative energy sources. It indicates that reform policy for consumer subsidy must be understood in line with more comprehensive regional energy plans to resolve energy poverty issue. - Research highlights: → Various factors are identified for low income households' fuel switching from coal to clean energy. → Coupon program and accessibility to alternative energy sources are considered; Result shows that accessible network to alternative clean energy sources is essential for low income group. → More comprehensive regional energy plans are required to resolve energy poverty issue.

Model for incorporating fuel swelling and clad shrinkage effects in diffusion theory calculations (LWBR Development Program)

International Nuclear Information System (INIS)

Schick, W.C. Jr.; Milani, S.; Duncombe, E.

1980-03-01

A model has been devised for incorporating into the thermal feedback procedure of the PDQ few-group diffusion theory computer program the explicit calculation of depletion and temperature dependent fuel-rod shrinkage and swelling at each mesh point. The model determines the effect on reactivity of the change in hydrogen concentration caused by the variation in coolant channel area as the rods contract and expand. The calculation of fuel temperature, and hence of Doppler-broadened cross sections, is improved by correcting the heat transfer coefficient of the fuel-clad gap for the effects of clad creep, fuel densification and swelling, and release of fission-product gases into the gap. An approximate calculation of clad stress is also included in the model

Analysis Of The Effect Of Fuel Enrichment Error On Neutronic Properties Of The RSG-GAS Core

International Nuclear Information System (INIS)

Saragih, Tukiran; Pinem, Surian

2002-01-01

The analysis of the fuel enrichment error effect on neutronic properties has been carried out. The fuel enrichment could be improperly done because of wrong fabrication. Therefore it is necessary to analyze the fuel enrichment error effect to determine how many percents the fuel enrichment maximum can be accepted in the core. The analysis was done by simulation method The RSG-GAS core was simulated with 5 standard fuels and 1 control element having wrong enrichment when inserted into the core. Fuel enrichment error was then simulated from 20%, 25% and 30% and the simulation was done using WIMSD/4 and Batan-2DIFF codes. The cross section of core material of the RSG-GAS was generated by WIMSD/4 code in 1-D, X-Y geometry and 10 energy neutron group. Two dimensions, diffusion calculation based on finite element method was done by using Batan-2DIFF code. Five fuel elements and one control element changed the enrichment was finally arranged as a new core of the RSG-Gas reactor. The neutronic properties can be seen from eigenvalues (k eff ) as well as from the kinetic properties based on moderator void reactivity coefficient. The calculated results showed that the error are still acceptable by k eff 1,097 even until 25% fuel enrichment but not more than 25,5%

Data feature: Fuel procurement

International Nuclear Information System (INIS)

Anon.

1994-01-01

This document is a review of the effect of fuel costs on the procurement strategies of a utility and a conjecture that the same strategies may have an effect on the price of fuel. Factors affecting fuel costs are reviewed, and a number of procurement strategies taken to trim fuel costs are reviewed. The major trend is away from long-term enrichment contracts and into such strategies as: (1) Spot market purchases, (2) Inventory reduction, (3) Purchase of CIS material, and (4) Market-related contracts instead of base-escalated contracts

Influences of in-fuel physical-chemical processes on serviceability of energy reactor fuel elements

Energy Technology Data Exchange (ETDEWEB)

Bibilashvili, Yu K; Nekrasova, G A; Sukhanov, G I

1989-01-01

In-fuel physico-chemical processes and their effect on stress corrosion cracking of fuel element zirconium cladding are considered in the review. The mechanism of fission product release from the fuel is studied and the negative role of primarily iodine on the cladding corrosion process is demonstrated. Directions for improving the fuel element claddings and fuel to increase the fuel element serviceability are specified.

Influences of in-fuel physical-chemical processes on serviceability of energy reactor fuel elements

International Nuclear Information System (INIS)

Bibilashvili, Yu.K.; Nekrasova, G.A.; Sukhanov, G.I.

1989-01-01

In-fuel physico-chemical processes and their effect on stress corrosion cracking of fuel element zirconium cladding are considered in the review. The mechanism of fission product release from the fuel is studied and the negative role of primarily iodine on the cladding corrosion process is demonstrated. Directions for improving the fuel element claddings and fuel to increase the fuel element serviceability are specified

Method of making a graphite fuel element having carbonaceous fuel bodies

International Nuclear Information System (INIS)

Miertschin, G.N.; Leary, D.F.

1977-01-01

Particulate nuclear fuel material, particulate carbon and pitch are combined with an additive which is effective to reduce the coke yield upon carbonization to mold a green fuel body. The additive may be polystyrene, a styrene-butadiene copolymer, an aromatic hydrocarbon having a molecular weight between about 75 and 300 or a saturated hydrocarbon polymer. The green fuel body is inserted in a complementary cavity within a porous nuclear fuel element body and heated in situ to decompose the pitch and additive, leaving a relatively close-fitting fuel body in the cavity

The effect of reference parameters and properties of materials for WWER-type fuel elements on their reliability

International Nuclear Information System (INIS)

Bibilashvili, Yu.K.; Malachenko, L.L.; Medvedev, A.V.; Solyany, V.I.; Sukhanov, G.I.; Tonkov, V.Yu.

1987-01-01

Present approach to requirements for reference parameters and properties of materials for WWER-1000 fuel elements is presented as well as evaluation of their effects on fuel reliability. Some results of investigations with the aim of improving fuel element reliability in operational NPP conditions are discussed. (author)

Impact of Fuel Failure on Criticality Safety of Used Nuclear Fuel

International Nuclear Information System (INIS)

Marshall, William J.; Wagner, John C.

2012-01-01

Commercial used nuclear fuel (UNF) in the United States is expected to remain in storage for considerably longer periods than originally intended (e.g., 45 GWd/t) may increase the potential for fuel failure during normal and accident conditions involving storage and transportation. Fuel failure, depending on the severity, can result in changes to the geometric configuration of the fuel, which has safety and regulatory implications. The likelihood and extent of fuel reconfiguration and its impact on the safety of the UNF is not well understood. The objective of this work is to assess and quantify the impact of fuel reconfiguration due to fuel failure on criticality safety of UNF in storage and transportation casks. This effort is primarily motivated by concerns related to the potential for fuel degradation during ES periods and transportation following ES. The criticality analyses consider representative UNF designs and cask systems and a range of fuel enrichments, burnups, and cooling times. The various failed-fuel configurations considered are designed to bound the anticipated effects of individual rod and general cladding failure, fuel rod deformation, loss of neutron absorber materials, degradation of canister internals, and gross assembly failure. The results quantify the potential impact on criticality safety associated with fuel reconfiguration and may be used to guide future research, design, and regulatory activities. Although it can be concluded that the criticality safety impacts of fuel reconfiguration during transportation subsequent to ES are manageable, the results indicate that certain configurations can result in a large increase in the effective neutron multiplication factor, k eff . Future work to inform decision making relative to which configurations are credible, and therefore need to be considered in a safety evaluation, is recommended.

Investigation of the effects of renewable diesel fuels on engine performance, combustion, and emissions

KAUST Repository

Ogunkoya, Dolanimi

2015-01-01

A study was undertaken to investigate renewable fuels in a compression-ignition internal combustion engine. The focus of this study was the effect of newly developed renewable fuels on engine performance, combustion, and emissions. Eight fuels were investigated, and they include diesel, jet fuel, a traditional biodiesel (fatty acid methyl ester: FAME), and five next generation biofuels. These five fuels were derived using a two-step process: hydrolysis of the oil into fatty acids (if necessary) and then a thermo-catalytic process to remove the oxygen via a decarboxylation reaction. The fuels included a fed batch deoxygenation of canola derived fatty acids (DCFA), a fed batch deoxygenation of canola derived fatty acids with varying amounts of H2 used during the deoxygenation process (DCFAH), a continuous deoxygenation of canola derived fatty acids (CDCFA), fed batch deoxygenation of lauric acid (DLA), and a third reaction to isomerize the products of the deoxygenated canola derived fatty acid alkanes (IPCF). Diesel, jet fuel, and biodiesel (FAME) have been used as benchmarks for comparing with the newer renewable fuels. The results of the experiments show slightly lower mechanical efficiency but better brake specific fuel consumption for the new renewable fuels. Results from combustion show shorter ignition delays for most of the renewable (deoxygenated) fuels with the exception of fed batch deoxygenation of lauric acid. Combustion results also show lower peak in-cylinder pressures, reduced rate of increase in cylinder pressure, and lower heat release rates for the renewable fuels. Emission results show an increase in hydrocarbon emissions for renewable deoxygenated fuels, but a general decrease in all other emissions including NOx, greenhouse gases, and soot. Results also demonstrate that isomers of the alkanes resulting from the deoxygenation of the canola derived fatty acids could be a potential replacement to conventional fossil diesel and biodiesel based on the

Effects of Ethanol-Gasoline Blended Fuels on Learning and Memory

Science.gov (United States)

The potential toxicity of ethanol-gasoline blended fuels to the developing nervous system is of concern. We previously reported an absence of effect on learning and memory as seen in a trace fear conditioning task and water maze task in offspring of dams exposed prenatally to the...

Spent fuel workshop'2002

Energy Technology Data Exchange (ETDEWEB)

Poinssot, Ch

2002-07-01

This document gathers the transparencies of the presentations given at the 2002 spent fuel workshop: Session 1 - Research Projects: Overview on the IN CAN PROCESSES European project (M. Cowper), Overview on the SPENT FUEL STABILITY European project (C. Poinssot), Overview on the French R and D project on spent fuel long term evolution, PRECCI (C. Poinssot); Session 2 - Spent Fuel Oxidation: Oxidation of uranium dioxide single crystals (F. Garrido), Experimental results on SF oxidation and new modeling approach (L. Desgranges), LWR spent fuel oxidation - effects of burn-up and humidity (B. Hanson), An approach to modeling CANDU fuel oxidation under dry storage conditions (P. Taylor); Session 3 - Spent Fuel Dissolution Experiments: Overview on high burnup spent fuel dissolution studies at FZK/INE (A. Loida), Results on the influence of hydrogen on spent fuel leaching (K. Spahiu), Leaching of spent UO{sub 2} fuel under inert and reducing conditions (Y. Albinsson), Fuel corrosion investigation by electrochemical techniques (D. Wegen), A reanalysis of LWR spent fuel flow through dissolution tests (B. Hanson), U-bearing secondary phases formed during fuel corrosion (R. Finch), The near-field chemical conditions and spent fuel leaching (D. Cui), The release of radionuclides from spent fuel in bentonite block (S.S. Kim), Trace actinide behavior in altered spent fuel (E. Buck, B. Hanson); Session 4 - Radiolysis Issues: The effect of radiolysis on UO{sub 2} dissolution determined from electrochemical experiments with {sup 238}Pu doped UO{sub 2} M. Stroess-Gascoyne (F. King, J.S. Betteridge, F. Garisto), doped UO{sub 2} studies (V. Rondinella), Preliminary results of static and dynamic dissolution tests with {alpha} doped UO{sub 2} in Boom clay conditions (K. Lemmens), Studies of the behavior of UO{sub 2} / water interfaces under He{sup 2+} beam (C. Corbel), Alpha and gamma radiolysis effects on UO{sub 2} alteration in water (C. Jegou), Behavior of Pu-doped pellets in brines

Reducing the fuel temperature for pressure-tube supercritical-water-cooled reactors and the effect of fuel burnup

Energy Technology Data Exchange (ETDEWEB)

Nichita, E., E-mail: eleodor.nichita@uoit.ca; Kovaltchouk, V., E-mail: vitali.kovaltchouk@uoit.ca

2015-12-15

Highlights: • Typical PT-SCWR fuel uses single-region pins consisting of a homogeneous mixture of ThO{sub 2} and PuO{sub 2}. • Using two regions (central for the ThO{sub 2} and peripheral for the PuO{sub 2}) reduces the fuel temperature. • Single-region-pin melting-to-average power ratio is 2.5 at 0.0 MW d/kg and 2.3 at 40 MW d/kg. • Two-region-pin melting-to-average power ratio is 36 at 0.0 MW d/kg and 10.5 at 40 MW d/kg. • Two-region-pin performance drops with burnup due to fissile-element buildup in the ThO{sub 2} region. - Abstract: The Pressure-Tube Supercritical-Water-Cooled Reactor (PT-SCWR) is one of the concepts under investigation by the Generation IV International Forum for its promise to deliver higher thermal efficiency than nuclear reactors currently in operation. The high coolant temperature (>625 K) and high linear power density employed by the PT-SCWR cause the fuel temperature to be fairly high, leading to a reduced margin to fuel melting, thus increasing the risk of actual melting during accident scenarios. It is therefore desirable to come up with a fuel design that lowers the fuel temperature while preserving the high linear power ratio and high coolant temperature. One possible solution is to separate the fertile (ThO{sub 2}) and fissile (PuO{sub 2}) fuel materials into different radial regions in each fuel pin. Previously-reported work found that by locating the fertile material at the centre and the fissile material at the periphery of the fuel pin, the fuel centreline temperature can be reduced by ∼650 K for fresh fuel compared to the case of a homogeneous (Th–Pu)O{sub 2} mixture for the same coolant temperature and linear power density. This work provides a justification for the observed reduction in fuel centreline temperature and suggests a systematic approach to lower the fuel temperature. It also extends the analysis to the dependence of the radial temperature profile on fuel burnup. The radial temperature profile is

Fuel charging machine

International Nuclear Information System (INIS)

Uchikawa, Sadao.

1978-01-01

Purpose: To enable continuous fuel discharging and charging steps in a bwr type reactor by effecting positioning only for once by providing a plurality of fuel assembly grippers and their drives co-axially on a rotatable surface. Constitution: A plurality of fuel assembly grippers and their drives are provided co-axially on a rotatable surface. For example, a gripper A, a drive B, a gripper C and a drive D are arranged co-axially in symmetric positions on a disk rotated on rails by wheels and rotational drives. A new fuel in a fuel pool is gripped by the gripper A and transported above the reactor core. Then, the disk is positioned so that the gripper C can grip the spent fuel in the core, and the fuel to be discharged is gripped and raised by the gripper C. Then the disk is rotated by 180 0 and the new fuel in the gripper A is charged into the position from which the old fuel has been discharged and, finally, the discharged fuel is sent to the fuel pool for storage. (Seki, T.)

Main conditions and effectiveness of gas fuel use for powering of dual fuel IC self-ignition engine

Directory of Open Access Journals (Sweden)

Stefan POSTRZEDNIK

2015-09-01

Full Text Available Internal combustion engines are fuelled mostly with liquid fuels (gasoline, diesel. Nowadays the gaseous fuels are applied as driving fuel of combustion engines. In case of spark ignition engines the liquid fuel (petrol can be totally replaced by the gas fuels. This possibility in case of compression engines is essentially restricted through the higher self-ignition temperatures of the combustible gases in comparison to classical diesel oil. Solution if this problem can be achieved by using of the dual fuel system, where for ignition of the prepared fuel gas - air mixture a specified amount of the liquid fuel (diesel oil should be additionally injected into the combustion chamber. For assurance that the combustion process proceeds without mistakes and completely, some basic conditions should be satisfied. In the frame of this work, three main aspects of this problem are taken into account: a. filling efficiency of the engine, b. stoichiometry of the combustion, c. performance of mechanical parameters (torque, power. A complex analysis of these conditions has been done and some achieved important results are presented in the paper.

Effect of phosphorus addition in combustion of biomass fuels; Effekter av fosfortillsats vid foerbraenning av biomassa

Energy Technology Data Exchange (ETDEWEB)

Grimm, Alejandro; Skoglund, Nils; Eriksson, Gunnar; Bostroem, Dan; Oehman, Marcus

2010-11-15

The results from this project show that phosphorous-rich additives could be of interest to reduce fouling and high temperature corrosion without causing increase in slagging and/or bed agglomeration tendency for typical biofuels. General results in this series of experiments show that in order to achieve a good potassium-binding effect the calcium and magnesium content should be low in the phosphorous-rich fuel and additive. If the content of Ca and Mg is high in the final fuel mixture (including both P-fuel/additive and the bulk fuel) the K-binding effect is reduced and more P needs to be added. Of course, this also means that the additive of choice (fuel or chemical) should have a low content of calcium and magnesium. It is therefore probable that the best results will be obtained when using a fuel mix where the final blend has a molar ratio of P/(K+Na+2/3Ca+2/3Mg) approaching 1. For instance, using monoammonium phosphate, this would be equivalent to a cost (autumn 2009) of about 9-14, 10-15 and 30-40 SEK in P-additive cost per MWh of added fuel to achieve this molar ratio for typical logging residue, salix and wheat straw biofuels.

Physical and chemical effects of low octane gasoline fuels on compression ignition combustion

KAUST Repository

Badra, Jihad

2016-09-30

Gasoline compression ignition (GCI) engines running on low octane gasoline fuels are considered an attractive alternative to traditional spark ignition engines. In this study, three fuels with different chemical and physical characteristics have been investigated in single cylinder engine running in GCI combustion mode at part-load conditions both experimentally and numerically. The studied fuels are: Saudi Aramco light naphtha (SALN) (Research octane number (RON) = 62 and final boiling point (FBP) = 91 °C), Haltermann straight run naphtha (HSRN) (RON = 60 and FBP = 140 °C) and a primary reference fuel (PRF65) (RON = 65 and FBP = 99 °C). Injection sweeps, where the start of injection (SOI) is changed between −60 and −11 CAD aTDC, have been performed for the three fuels. Full cycle computational fluid dynamics (CFD) simulations were executed using PRFs as chemical surrogates for the naphtha fuels. Physical surrogates based on the evaporation characteristics of the naphtha streams have been developed and their properties have been implemented in the engine simulations. It was found that the three fuels have similar combustion phasings and emissions at the conditions tested in this work with minor differences at SOI earlier than −30 CAD aTDC. These trends were successfully reproduced by the CFD calculations. The chemical and physical effects were further investigated numerically. It was found that the physical characteristics of the fuel significantly affect the combustion for injections earlier than −30 CAD aTDC because of the low evaporation rates of the fuel because of the higher boiling temperature of the fuel and the colder in-cylinder air during injection. © 2016 Elsevier Ltd

Effects of dimethyl ether on the performance characteristics of a direct methanol fuel cell

International Nuclear Information System (INIS)

Seo, Sang Hern; Lee, Chang Sik

2013-01-01

Highlights: • Activation loss is significantly reduced in fuel cell with DME-methanol. • DME crossover through the membrane reduces. • The open circuit voltage of DME-methanol the fuel cell increases. • The overall efficiency of the mixed fuel cell is higher than that of DMFC. - Abstract: The objective of this study was to determine the effects of dimethyl ether (DME) on the performance characteristics of a direct methanol fuel cell. Impedance and crossover experiments were performed in order to investigate the performance losses such as ohmic loss, activation loss and crossover loss accurately. The DME was pressurized to 5 bar to supply with liquid phase was and blended with an aqueous methanol solution. In this experiment, the membrane electrode assembly (MEA) was composed of Nafion 115, anode catalyst loaded Pt–Ru and cathode catalyst loaded Pt-Black. Experimental results showed that fuel cells with DME-methanol enhanced performance when compared to fuel cells with methanol only. Such performance enhancement was due to a decrease in activation losses by DME oxidation reactions. As the DME crossover through the membrane was reduced, the open circuit voltage (OCV) of the fuel cell increased. Other output characteristics are also discussed

Prediction models for density and viscosity of biodiesel and their effects on fuel supply system in CI engines

Energy Technology Data Exchange (ETDEWEB)

Tesfa, B.; Mishra, R.; Gu, F. [Computing and Engineering, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH (United Kingdom); Powles, N. [Chemistry and Forensic Science, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH (United Kingdom)

2010-12-15

Biodiesel is a promising non-toxic and biodegradable alternative fuel used in the transport sector. Nevertheless, the higher viscosity and density of biodiesel poses some acute problems when it is used it in unmodified engine. Taking this into consideration, this study has been focused towards two objectives. The first objective is to identify the effect of temperature on density and viscosity for a variety of biodiesels and also to develop a correlation between density and viscosity for these biodiesels. The second objective is to investigate and quantify the effects of density and viscosity of the biodiesels and their blends on various components of the engine fuel supply system such as fuel pump, fuel filters and fuel injector. To achieve first objective density and viscosity of rapeseed oil biodiesel, corn oil biodiesel and waste oil biodiesel blends (0B, 5B, 10B, 20B, 50B, 75B, and 100B) were tested at different temperatures using EN ISO 3675:1998 and EN ISO 3104:1996 standards. For both density and viscosity new correlations were developed and compared with published literature. A new correlation between biodiesel density and biodiesel viscosity was also developed. The second objective was achieved by using analytical models showing the effects of density and viscosity on the performance of fuel supply system. These effects were quantified over a wide range of engine operating conditions. It can be seen that the higher density and viscosity of biodiesel have a significant impact on the performance of fuel pumps and fuel filters as well as on air-fuel mixing behaviour of compression ignition (CI) engine. (author)

Steady state investigation on neutronics of a molten salt reactor considering the flow effect of fuel salt

Institute of Scientific and Technical Information of China (English)

ZHANG Da-Lin; QIU Sui-Zheng; LIU Chang-Liang; SU Guang-Hui

2008-01-01

The Molten Salt Reactor (MSR),one of the‘Generation Ⅳ'concepts,is a liquid-fuel reactor,which is different from the conventional reactors using solid fissile materials due to the flow effect of fuel salt.The study on its neutronice considering the fuel salt flow,which is the base of the thermal-hydraulic calculation and safety analysis,must be done.In this paper,the theoretical model on neutronics under steady condition for a single-liquid-fueled MSR is conducted and calculated by numerical method.The neutronics model consists of two group neutron diffusion equations for fast and thermal neutron fluxes,and balance equations for six-group delayed neutron precursors considering the flow effect of fuel salt. The spatial discretization of the above models is based on the finite volume method,and the discretization equations are computed by the source iteration method.The distributions of neutron fluxes and the distributions of the delayed neutron precursors in the core are obtained.The numerical calculated results show that,the fuel salt flow has little effect on the distribution of fast and thermal neutron fluxes and the effective multiplication factor;however,it affects the distribution of the delayed neutron precursors significantly,especially the long-lived one.In addition,it could be found that the delayed neutron precursors influence the nentronics slightly under the steady condition.

Steady state investigation on neutronics of a molten salt reactor considering the flow effect of fuel salt

International Nuclear Information System (INIS)

Zhang Dalin; Qiu Suizheng; Su Guanghui; Liu Changliang

2008-01-01

The Molten Salt Reactor (MSR), one of the 'Generation IV' concepts, is a liquid-fuel reactor, which is different from the conventional reactors using solid fissile materials due to the flow effect of fuel salt. The study on its neutronics considering the fuel salt flow, which is the base of the thermal-hydraulic calculation and safety analysis, must be done. In this paper, the theoretical model on neutronics under steady condition for a single-liquid-fueled MSR is conducted and calculated by numerical method. The neutronics model consists of two group neutron diffusion equations for fast and thermal neutron fluxes, and balance equations for six-group delayed neutron precursors considering the flow effect of fuel salt. The spatial discretization of the above models is based on the finite volume method, and the discretization equations are computed by the source iteration method. The distributions of neutron fluxes and the distributions of the delayed neutron precursors in the core are obtained. The numerical calculated results show that, the fuel salt flow has little effect on the distribution of fast and thermal neutron fluxes and the effective multiplication factor; however, it affects the distribution of the delayed neutron precursors significantly, especially the long-lived one. In addition, it could be found that the delayed neutron precursors influence the neutronics slightly under the steady condition. (authors)

The role of spent fuel test facilities in the fuel cycle strategy

International Nuclear Information System (INIS)

Huang, S. T.; Gross, D. L.; Snyder, N. W.; Woods, W. D.

1988-01-01

Disposal of commercial spent nuclear fuels in the major industrialized countries may be categorized into two broad approaches: a once-through policy which will dispose of spent fuels and recycle fissile materials. Within reprocess spent fuels and recycle fissile materials. Within each policy, various technical, licensing, institutional and public issues exist. These issues tend to complicate the formulation of an effective and acceptable fuel cycle strategy which will meet various cost, schedule, and legislative constraints. This paper examines overall fuel cycle strategies from the viewpoint of these underlying technical issues and assesses the roles of spent fuel test facilities in the overall fuel cycles steps. Basic functions of such test facilities are also discussed. The main emphasis is placed on the once-through policy although the reprocessing / recycle policy is also discussed. Benefits of utilizing test facilities in the fuel cycle strategies are explored. The results indicate that substantial benefits may be obtained in terms of minimizing programmatic risks, increasing public confidence, and more effective utilization of overall budgetary resources by structuring and highlighting the test facilities as an important element in the overall strategy

The Fuel Performance Analysis of LWR Fuel containing High Thermal Conductivity Reinforcements

International Nuclear Information System (INIS)

Kim, Seung Su; Ryu, Ho Jin

2015-01-01

The thermal conductivity of fuel affects many performance parameters including the fuel centerline temperature, fission gas release and internal pressure. In addition, enhanced safety margin of fuel might be expected when the thermal conductivity of fuel is improved by the addition of high thermal conductivity reinforcements. Therefore, the effects of thermal conductivity enhancement on the fuel performance of reinforced UO2 fuel with high thermal conductivity compounds should be analyzed. In this study, we analyzed the fuel performance of modified UO2 fuel with high thermal conductivity reinforcements by using the FRAPCON-3.5 code. The fissile density and mechanical properties of the modified fuel are considered the same with the standard UO2 fuel. The fuel performance of modified UO2 with high thermal conductivity reinforcements were analyzed by using the FRAPCON-3.5 code. The thermal conductivity enhancement factors of the modified fuels were obtained from the Maxwell model considering the volume fraction of reinforcements

Numerical Investigation of Fuel Distribution Effect on Flow and Temperature Field in a Heavy Duty Gas Turbine Combustor

Science.gov (United States)

Deng, Xiaowen; Xing, Li; Yin, Hong; Tian, Feng; Zhang, Qun

2018-03-01

Multiple-swirlers structure is commonly adopted for combustion design strategy in heavy duty gas turbine. The multiple-swirlers structure might shorten the flame brush length and reduce emissions. In engineering application, small amount of gas fuel is distributed for non-premixed combustion as a pilot flame while most fuel is supplied to main burner for premixed combustion. The effect of fuel distribution on the flow and temperature field related to the combustor performance is a significant issue. This paper investigates the fuel distribution effect on the combustor performance by adjusting the pilot/main burner fuel percentage. Five pilot fuel distribution schemes are considered including 3 %, 5 %, 7 %, 10 % and 13 %. Altogether five pilot fuel distribution schemes are computed and deliberately examined. The flow field and temperature field are compared, especially on the multiple-swirlers flow field. Computational results show that there is the optimum value for the base load of combustion condition. The pilot fuel percentage curve is calculated to optimize the combustion operation. Under the combustor structure and fuel distribution scheme, the combustion achieves high efficiency with acceptable OTDF and low NOX emission. Besides, the CO emission is also presented.

Effect of fuel particles' size variations on multiplication factor in pebble-bed nuclear reactor

International Nuclear Information System (INIS)

Snoj, L.; Ravnik, M.

2005-01-01

The pebble-bed reactor (Pbr) spherical fuel element consists of two radial zones: the inner zone, in which the fissile material in form of the so-called TRISO particles is uniformly dispersed in graphite matrix and the outer zone, a shell of pure graphite. A TRISO particle is composed of a fissile kernel (UO 2 ) and several layers of carbon composites. The effect of TRISO particles' size variations and distance between them on PBR multiplication factor is studied using MCNP code. Fuel element is modelled in approximation of a cubical unit cell with periodic boundary condition. The multiplication factor of the fuel element depends on the size of the TRISO particles due to resonance self-shielding effect and on the inter-particle distance due to inter-kernel shadowing. (author)

Fuel assembly

International Nuclear Information System (INIS)

Sano, Hiroki; Fushimi, Atsushi; Tominaga, Kenji; Aoyama, Motoo; Ishii, Kazuya.

1997-01-01

In burnable poison-incorporated uranium fuels of a BWR type reactor, the compositional ratio of isotopes of the burnable poisons is changed so as to increase the amount of those having a large neutron absorbing cross sectional area. For example, if the ratio of Gd-157 at the same burnable poison enrichment degree is made greater than the natural ratio, this gives the same effect as the increase of the enrichment degree per one fuel rod, thereby providing an effect of reducing a surplus reactivity. Gadolinium, hafnium and europium as burnable poisons have an absorbing cross sectional area being greater in odd numbered nuclei than in even numbered nuclei, on the contrary, boron has a cross section being greater in even numbered nucleus than odd numbered nuclei. Accordingly, if the ratio of isotopes having greater cross section at the same burnable poison enrichment degree is made greater than the natural ratio, surplus reactivity at the initial stage of the burning can be reduced without greatly increasing the amount of burnable poison-incorporated uranium fuels, fuel loading amount is not reduced and the fuel economy is not worsened. (N.H.)

Nuclear fuels

International Nuclear Information System (INIS)

Beauvy, M.; Berthoud, G.; Defranceschi, M.; Ducros, G.; Guerin, Y.; Limoge, Y.; Madic, Ch.; Santarini, G.; Seiler, J.M.; Sollogoub, P.; Vernaz, E.; Guillet, J.L.; Ballagny, A.; Bechade, J.L.; Bonin, B.; Brachet, J.Ch.; Delpech, M.; Dubois, S.; Ferry, C.; Freyss, M.; Gilbon, D.; Grouiller, J.P.; Iracane, D.; Lansiart, S.; Lemoine, P.; Lenain, R.; Marsault, Ph.; Michel, B.; Noirot, J.; Parrat, D.; Pelletier, M.; Perrais, Ch.; Phelip, M.; Pillon, S.; Poinssot, Ch.; Vallory, J.; Valot, C.; Pradel, Ph.; Bonin, B.; Bouquin, B.; Dozol, M.; Lecomte, M.; Vallee, A.; Bazile, F.; Parisot, J.F.; Finot, P.; Roberts, J.F.

2009-01-01

fuel, Anticipated evolution of fuel in dry storage, Anticipated evolution of fuel in deep geological disposal); Boiling-water reactor fuel (Similarities, and differences with PWR fuel, Axial and radial zoning, Rod and channel box sizes, Poisoning and reactivity control, Cladding specific characteristics, Trends in fuel evolution); 3 - Liquid-metal-cooled fast reactor fuel: Fast-neutron irradiation damage in structural materials (Fast-neutron-induced damage in metals, What materials should be used?); Fuels and targets for fast-reactor transmutation (Fast reactors: reactors affording the ability to carry out effective actinide transmutation, Recycling: homogeneous, or heterogeneous?); 4 - gas-cooled reactor fuel: Particle fuel (From the initial concept to the advanced TRISO particle concept, Kernel fabrication processes, Particle coating by chemical vapor deposition, Fuel element fabrication: particle compaction, Characterization of fuel particles, and elements, From HTR fuel to VHTR and GFR fuels: the GAIA facility at CEA/Cadarache); Irradiation behavior of particle fuels (Particle fuel: a variety of failure modes for a high-strength object, The amoeba effect, Fission product behavior, and diffusion in particle fuels); Mechanical modeling of particle fuel; Very-high-temperature reactor (VHTR) fuel; Gas-cooled fast reactor (GFR) fuel (The specifications for GFR fuel, GFR fissile material, First containment baffler materials, GFR fuel element concepts); 5 - Research reactor fuels (A considerable feedback from experience, Conversion of French reactors to low-enriched (≤20% U-235)U 3 Si 2 fuel, Conversion of all reactors: R and D requirements for high-performance reactors, An 'advanced' research reactor fuel: UMo, The startup fuel for the Jules Horowitz Reactor (JHR) will still be U 3 Si 2 -Al; 6 - An instrument for future fuel research: the Jules Horowitz Reactor (JHR): Fuel irradiation experiments in JHR, JHR: a flexible instrument; 7 - Glossary-Index

Nuclear fuels

Energy Technology Data Exchange (ETDEWEB)

Beauvy, M.; Berthoud, G.; Defranceschi, M.; Ducros, G.; Guerin, Y.; Limoge, Y.; Madic, Ch.; Santarini, G.; Seiler, J.M.; Sollogoub, P.; Vernaz, E.; Guillet, J.L.; Ballagny, A.; Bechade, J.L.; Bonin, B.; Brachet, J.Ch.; Delpech, M.; Dubois, S.; Ferry, C.; Freyss, M.; Gilbon, D.; Grouiller, J.P.; Iracane, D.; Lansiart, S.; Lemoine, P.; Lenain, R.; Marsault, Ph.; Michel, B.; Noirot, J.; Parrat, D.; Pelletier, M.; Perrais, Ch.; Phelip, M.; Pillon, S.; Poinssot, Ch.; Vallory, J.; Valot, C.; Pradel, Ph.; Bonin, B.; Bouquin, B.; Dozol, M.; Lecomte, M.; Vallee, A.; Bazile, F.; Parisot, J.F.; Finot, P.; Roberts, J.F

2009-07-01

nature of spent nuclear fuel, Anticipated evolution of fuel in dry storage, Anticipated evolution of fuel in deep geological disposal); Boiling-water reactor fuel (Similarities, and differences with PWR fuel, Axial and radial zoning, Rod and channel box sizes, Poisoning and reactivity control, Cladding specific characteristics, Trends in fuel evolution); 3 - Liquid-metal-cooled fast reactor fuel: Fast-neutron irradiation damage in structural materials (Fast-neutron-induced damage in metals, What materials should be used?); Fuels and targets for fast-reactor transmutation (Fast reactors: reactors affording the ability to carry out effective actinide transmutation, Recycling: homogeneous, or heterogeneous?); 4 - gas-cooled reactor fuel: Particle fuel (From the initial concept to the advanced TRISO particle concept, Kernel fabrication processes, Particle coating by chemical vapor deposition, Fuel element fabrication: particle compaction, Characterization of fuel particles, and elements, From HTR fuel to VHTR and GFR fuels: the GAIA facility at CEA/Cadarache); Irradiation behavior of particle fuels (Particle fuel: a variety of failure modes for a high-strength object, The amoeba effect, Fission product behavior, and diffusion in particle fuels); Mechanical modeling of particle fuel; Very-high-temperature reactor (VHTR) fuel; Gas-cooled fast reactor (GFR) fuel (The specifications for GFR fuel, GFR fissile material, First containment baffler materials, GFR fuel element concepts); 5 - Research reactor fuels (A considerable feedback from experience, Conversion of French reactors to low-enriched ({<=}20% U-235)U{sub 3}Si{sub 2} fuel, Conversion of all reactors: R and D requirements for high-performance reactors, An 'advanced' research reactor fuel: UMo, The startup fuel for the Jules Horowitz Reactor (JHR) will still be U{sub 3}Si{sub 2}-Al; 6 - An instrument for future fuel research: the Jules Horowitz Reactor (JHR): Fuel irradiation experiments in JHR, JHR: a flexible

Irradiation effects on mechanical properties of fuel element cladding from thermal reactors

International Nuclear Information System (INIS)

Chatterjee, S.

2005-01-01

During reactor operation, UO 2 expands more than the cladding tube (Zirconium alloys for thermal reactors), is hotter, cracks and swells. The fuel therefore will interact with the cladding, resulting in straining of the later. To minimize the possibility of rupture of the cladding, ideally it should have good ductility as well as high strength. However, the ductility reduces with increase in fuel element burn-up. Increased burn-up also increases swelling of the fuel, leading to increased contact pressure between the fuel and the cladding tube. This would cause strains to be concentrated over localized regions of the cladding. For fuel elements burnup exceeding 40 GWd/T, the contribution of embrittlement due to hydriding, and the increased possibility of embrittlement due to stress corrosion cracking, also need to be considered. In addition to the tensile properties, the other mechanical properties of interest to the performance of cladding tube in an operating fuel element are creep rate and fatigue endurance. Irradiation is reported to have insignificant effect on high cycle endurance limit, and fatigue from fuel element vibration is most unlikely, to be life limiting. Even though creep rates due to irradiation are reported to increase by an order of magnitude, the cladding creep ductility would be so high that creep type failures in fuel element would be most improbable. Thus, the most important limiting aspect of mechanical performance of fuel element cladding has been recognized as the tensile ductility resulting from the stress conditions experienced by the cladding. Some specific fission products of threshold amount (if) deposited on the cladding, and hydride morphology (e.g. hydride lenses). The presentation will brief about irradiation damage in cladding materials and its significance, background of search for better Zirconium alloys as cladding materials, and elaborate on the types of mechanical tests need to be conducted for the evaluation of claddings

Effect of variation in LPG composition on emissions and performance in a dual fuel diesel engine

Energy Technology Data Exchange (ETDEWEB)

H.E. Saleh [Mattaria, Helwan University, Cairo (Egypt). Department of Mechanical Power Engineering

2008-10-15

This paper investigates the effect of variation in LPG composition on emissions and performance characteristics in a dual fuel engine run on diesel fuel and five gaseous fuel of LPG with different composition. To quantify the best LPG composition for dual fuel operation especially in order to improve the exhaust emissions quality while maintaining high thermal efficiency comparable to a conventional diesel engine, a two-cylinder, naturally aspirated, four-stroke, DI diesel engine converted to run as pilot-injected dual fuel engine. The tests and data collection were performed under various conditions of load at constant engine speed. From the results, it is observed that the exhaust emissions and fuel conversion efficiency of the dual fuel engine are found to be affected when different LPG composition is used as higher butane content lead to lower NOx levels while higher propane content reduces CO levels. Fuel No. 3 (70% propane, 30% butane) with mass fraction 40% substitution of the diesel fuel was the best LPG composition in the dual fuel operation except that at part loads. Also, tests were made for fuel No. 3-diesel blend in the dual fuel operation at part loads to improve the engine performances and exhaust emissions by using the Exhaust Gas Recirculation (EGR) method. 26 refs., 15 figs., 5 tabs.

Effects of coal-derived trace species on the performance of molten carbonate fuel cells

Energy Technology Data Exchange (ETDEWEB)

Pigeaud, A.

1991-10-01

The overall objective of the present study was to determine in detail the interaction effects of 10 simultaneously present, coal-gas contaminants, both on each other and on components of the Carbonate Fuel Cell. The primary goal was to assess underlying chemistries and reaction mechanisms which may cause decay in fuel cell performance or endurance as a result of both physics-chemical and/or mechanical interactions with the cell components and internal fuel cell parts. It was found, both from theory and cell test evidence, that trace contaminant interactions may occur with: Fuel-cell Electrodes (e.g., in this study with the Ni-anode), Lithium/Potassium Carbonate Electrolyte, Nickel and SS-Hardware, and by Mechanical Obstruction of Gas Flow in the Anode Plenum.

Effect of fuel string relocation on the consequences of postulated inlet header LBLOCA in KANUPP reactor

International Nuclear Information System (INIS)

Ahmed, I.; Chow, H.C.; Younis, M.H.

1996-01-01

An investigation aimed at determining the effect of fuel string relocation on reactivity excursion and power pulse following a hypothetical Large Break Loss of Coolant Accident in KANUPP reactor is reported. The assessment of reactivity insertion was performed making use of global (reactor) core analysis computer code RFSP. The reactor kinetics module CERBERUS of the RFSP code and the SOPHT (thermal-hydraulics code) were subsequently employed for the neutronic transient analysis. The effect was evaluated in context of determining the adequacy of moderator dump shutdown system. Because of the presence of the gap between the inlet shield plug and the fuel string, the fuel bundles may shift in such a manner that low-irradiated fuel is moved towards the core centre. This represents an additional reactivity increase to be accounted for in the analysis. The reactivity excursion, however, is alleviated by an earlier reactor trip. The net impact is that the energy deposited in the maximum rated fuel pencil is increased from 56% of the 960 kJ/kg fuel-centre-line melting limit to 63%. The result demonstrated the adequacy of the shutdown system against the maximum credible accident event. (author)

Effect of inlet fuel type on the degradation of Ni/YSZ anode of solid oxide fuel cell by carbon deposition

Directory of Open Access Journals (Sweden)

Suttichai Assabumrungrat

2006-11-01

Full Text Available According to the high operating temperature of Solid Oxide Fuel Cell (SOFC (700-1100ºC, it is known that some hydrocarbon fuels can be directly used as inlet fuel instead of hydrogen by feeding straight to the anode. This operation is called a direct internal reforming SOFC (DIR-SOFC. However, the major difficulty of this operation is the possible degradation of anode by the carbon deposition, as the carbon species are easily formed. In the present work, the effect of inlet fuel (i.e. H2, synthesis gas (H2+CO, CH4, CH4+H2O, CH3OH+H2O, and C2H5OH+H2O on the degradation of nickel cermet (Ni/YSZ, which is the most common anode material of SOFC, was studied.It was found from the work that hydrogen and synthesis gas (CO+H2 are proper to be used as direct inlet fuels for DIR-SOFC with Ni/YSZ anode, since the carbon formation on Ni/YSZ occurred in the small quantity. The mixture of methane and steam (CH4+H2O can also be used as the inlet feed, but the H2O/CH4 ratio plays an important role. In contrast, pure methane (CH4, methanol with steam (CH3OH+H2O and ethanol with steam (C2H5OH+H2O are not suitable for using as direct inlet fuel for DIR-SOFC with Ni/YSZ anode even the higher H2O/CH3OH and H2O/C2H5OH ratios were applied.

Elements of nuclear reactor fueling theory

International Nuclear Information System (INIS)

Egan, M.R.

1984-01-01

Starting with a review of the simple batch size effect, a more general theory of nuclear fueling is derived to describe the behavior and physical requirements of operating cycle sequences and fueling strategies having practical use in the management of nuclear fuel. The generalized theory, based on linear reactivity modeling, is analytical and represents the effects of multiple-stream, multiple-depletion-batch fueling configurations in systems employing arbitrary, non-integer batch size strategies, and containing fuel with variable energy generation rates. Reactor operating cycles and cycle sequences are represented with realistic structure that includes the effects of variable cycle energy production, cycle lengths, end-of-cycle operating extensions and maneuvering allowances. Results of the analytical theory are first applied to the special case of degenerate equilibrium cycle sequences, yielding several fundamental principles related to the selection of refueling strategy, and which govern fueling decisions normally made by the fuel manager. It is also demonstrated in this application that the simple batch size effect is not valid for non-integer fueling strategies, even in the simplest sequence configurations, and that it systematically underestimates the fueling requirements of degenerate sequences in general

Fuel density effect on near nozzle flow field in small laminar coflow diffusion flames

KAUST Repository

Xiong, Yuan

2015-01-01

Flow characteristics in small coflow diffusion flames were investigated with a particular focus on the near-nozzle region and on the buoyancy force exerted on fuels with densities lighter and heavier than air (methane, ethylene, propane, and n-butane). The flow-fields were visualized through the trajectories of seed particles. The particle image velocimetry technique was also adopted for quantitative velocity field measurements. The results showed that the buoyancy force exerted on the fuel as well as on burnt gas significantly distorted the near-nozzle flow-fields. In the fuels with densities heavier than air, recirculation zones were formed very close to the nozzle, emphasizing the importance of the relative density of the fuel to that of the air on the flow-field. Nozzle heating influenced the near-nozzle flow-field particularly among lighter fuels (methane and ethylene). Numerical simulations were also conducted, focusing specifically on the effect of specifying inlet boundary conditions for fuel. The results showed that a fuel inlet boundary with a fully developed velocity profile for cases with long tubes should be specified inside the fuel tube to permit satisfactory prediction of the flow-field. The calculated temperature fields also indicated the importance of the selection of the location of the inlet boundary, especially in testing various combustion models that include soot in small coflow diffusion flames. © 2014 The Combustion Institute.

Reducing Fuel Volatility. An Additional Benefit From Blending Bio-fuels?

Energy Technology Data Exchange (ETDEWEB)

Bailis, R. [Yale School of Forestry and Environmental Studies, 195 Prospect Street, New Haven, CT 06511 (United States); Koebl, B.S. [Utrecht University, Science Technology and Society, Budapestlaan 6, 3584 CD Utrecht (Netherlands); Sanders, M. [Utrecht University, Utrecht School of Economics, Janskerkhof 12, 3512 BL Utrecht (Netherlands)

2011-02-15

Oil price volatility harms economic growth. Diversifying into different fuel types can mitigate this effect by reducing volatility in fuel prices. Producing bio-fuels may thus have additional benefits in terms of avoided damage to macro-economic growth. In this study we investigate trends and patterns in the determinants of a volatility gain in order to provide an estimate of the tendency and the size of the volatility gain in the future. The accumulated avoided loss from blending gasoline with 20 percent ethanol-fuel estimated for the US economy amounts to 795 bn. USD between 2010 and 2019 with growing tendency. An amount that should be considered in cost-benefit analysis of bio-fuels.

Proceedings of fuel strategies for conventional and unconventional fuels

International Nuclear Information System (INIS)

Mahr, D.; Nechvatal, T.T.

1991-01-01

Fuel selection is a major decision for a power engineer. It is the single largest item in the power plant operating budget and has a major effect on power plant economics. Fuel determines plant design requirements and the types of systems that are provided. As a result, it affects capital budgets and financing requirements. In the last few decades, we have seen different fuels of choice at any one time. Coal has always been a staple for power generation. During the 1950s and 1960s, oil became an attractive alternative. Nuclear fuel became a popular choice due to its very low energy cost. After Three-Mile-Island, however, capital budgets went through the roof, resulting in severe financial constraints. Natural gas, which was rationed in some regions a few years ago, is now a popular choice. Some sources predict that its cost will increase faster than other fuels. To mitigate the relative variations in energy cost for different fuels, a balanced energy plan is required. A balanced power generation plan with fuel options provides the flexibility to react to unpredictable changes. The papers in this book are a continuation of the Fuel Strategies theme. Three technical topics are covered: Converting to Orimulsion, A Replacement Fuel for Heavy Oil; Innovations in Handling Conventional and Unconventional Fuels for Power Plants; and Pacific Rim Experience With Coal

Sulphur in liquid fuels 2002

Energy Technology Data Exchange (ETDEWEB)

Guthrie, J. [Environment Canada, Gatineau, PQ (Canada). Fuels Div., Oil, Gas and Energy Branch ; Sabourin, R. [Carleton Univ., Ottawa, ON (Canada)

2003-08-01

Environment Canada has developed new regulations for sulphur content in fuels in an effort to align with requirements recently passed by the U.S. Environmental Protection Agency. This report summarizes data regarding sulphur content in liquid fuels for the year 2002. The requirements of the Sulphur in Gasoline Regulation came into effect in 2002, limiting the average sulphur content of gasoline to 150 mg/kg. In January 2005, a 30 mg/kg average limit will come into effect. Also, in July 2002, the Sulphur in Diesel Fuel Regulation stipulated a maximum limit of 500 mg/kg for on-road diesel fuel. The new regulation continues this limit until mid-2006 at which time a 15 mg/kg limit will come into effect for on-road diesel fuel. Nationally, the average sulphur content in gasoline in 2002 was 246 mg/kg, which was 14.3 per cent lower than in 2001. The data covers the period from January 1 to December 31, 2002 and was obtained from petroleum refineries and importing companies that are required to submit quarterly information to the regional office of Environment Canada. Failure to comply results in penalties. The report includes data for aviation turbo fuel, motor gasoline, aviation gasoline, kerosene oil, low-sulphur diesel fuel, diesel fuel, light fuel oil, and heavy fuel oil. 16 tabs., 17 figs., 7 appendices.

Sanitary effects of fossil fuels; Effets sanitaires des combustibles fossiles

Energy Technology Data Exchange (ETDEWEB)

Nifenecker, H. [Centre National de la Recherche Scientifique (IN2P3/CNRS), 38 - Grenoble (France)

2006-07-01

In this compilation are studied the sanitary effects of fossil fuels, behavioral and environmental sanitary risks. The risks in connection with the production, the transport and the distribution(casting) are also approached for the oil(petroleum), the gas and the coal. Accidents in the home are evoked. The risks due to the atmospheric pollution are seen through the components of the atmospheric pollution as well as the sanitary effects of this pollution. (N.C.)

Evaluation of Effective thermal conductivity models on the prismatic fuel block of a Very High Temperature Reactor by CFD analysis

International Nuclear Information System (INIS)

Shin, Dong-Ho; Cho, Hyoung-Kyu; Tak, Nam-Il; Park, Goon-Cherl

2014-01-01

Effective thermal conductivity models which can be used to analyze the heat transfer phenomena of a prismatic fuel block were evaluated by CFD analysis. In the accident condition of VHTR when forced convection is lost, the heat flows in radial direction through the hexagonal fuel blocks that contain the large number of coolant holes and fuel compacts. Due to the complex geometry of fuel block and radiation heat transfer; the detail heat transfer computation on the fuel block needs excessive computation resources. Therefore, the detail computation isn’t appropriate for the lumped parameter code. The system code such as GAMMA+ adopts effective thermal conductivity model. Despite the complexity in heat transfer modes, the accurate analysis on the heat transfer in fuel block is necessary since it is directly relevant to the integrity of nuclear fuel embedded in fuel block. To satisfy the accurate analysis of complex heat transfer modes with limited computing sources, the credible effective thermal conductivity (ETC) models in which the effects of all of heat transfer modes are lumped is necessary. In this study, various ETC models were introduced and they are evaluated with CFD calculations. It is estimated that Maxwell-based model was the most pertinent one among the introduced ETC models. (author)

Thermal Radiation Effects on Thermal Explosion in Polydisperse Fuel Spray-Probabilistic Model

Directory of Open Access Journals (Sweden)

Ophir Navea

2011-06-01

Full Text Available We investigate the effect of thermal radiation on the dynamics of a thermal explosion of polydisperse fuel spray with a complete description of the chemistry via a single-step two-reactant model of general order. The polydisperse spray is modeled using a Probability Density Function (PDF. The thermal radiation energy exchange between the evaporation surface of the fuel droplets and the burning gas is described using the Marshak boundary conditions. An explicit expression of the critical condition for thermal explosion limit is derived analytically and represents a generalization of the critical parameter of the classical Semenov theory. Because we investigated the model in the range where the temperature is very high, the effect of the thermal radiation is significant.

Bio-fuel barometer

International Nuclear Information System (INIS)

2015-01-01

After a year of doubt and decline the consumption of bio-fuel resumed a growth in 2014 in Europe: +6.1% compared to 2013, to reach 14 millions tep (Mtep) that is just below the 2012 peak. This increase was mainly due to bio-diesel. By taking into account the energy content and not the volume, the consumption of bio-diesel represented 79.7% of bio-fuel consumption in 2014, that of bio-ethanol only 19.1% and that of biogas 1%. The incorporating rate of bio-fuels in fuels used for transport were 4.6% in 2013 and 4.9% in 2014. The trend is good and the future of bio-fuel seems clearer as the European Union has set a not-so-bad limit of 7% for first generation bio-fuels in order to take into account the CASI effect. The CASI effect shows that an increase of the consumption of first generation bio-fuels (it means bio-fuels produced from food crops like rape, soy, cereals, sugar beet,...) implies in fact a global increase in greenhouse gas release that is due to a compensation phenomenon. More uncultivated lands (like forests, grasslands, bogs are turned into cultivated lands in order to compensate lands used for bio-fuel production. In most European countries the consumption of bio-diesel increased in 2014 while it was a bad year for the European industry of ethanol because ethanol prices dropped by 16 %. Oil companies are now among the most important producers of bio-diesel in Europe.

Effects of Biodiesel Blend on Marine Fuel Characteristics for Marine Vessels

Directory of Open Access Journals (Sweden)

Cherng-Yuan Lin

2013-09-01

Full Text Available Biodiesel produced from vegetable oils, animal fats and algae oil is a renewable, environmentally friendly and clean alternative fuel that reduces pollutants and greenhouse gas emissions in marine applications. This study investigates the influence of biodiesel blend on the characteristics of residual and distillate marine fuels. Adequate correlation equations are applied to calculate the fuel properties of the blended marine fuels with biodiesel. Residual marine fuel RMA has inferior fuel characteristics compared with distillate marine fuel DMA and biodiesel. The flash point of marine fuel RMA could be increased by 20% if blended with 20 vol% biodiesel. The sulfur content of residual marine fuel could meet the requirement of the 2008 MARPOL Annex VI Amendment by blending it with 23.0 vol% biodiesel. In addition, the kinematic viscosity of residual marine fuel could be reduced by 12.9% and the carbon residue by 23.6% if 20 vol% and 25 vol% biodiesel are used, respectively. Residual marine fuel blended with 20 vol% biodiesel decreases its lower heating value by 1.9%. Moreover, the fuel properties of residual marine fuel are found to improve more significantly with biodiesel blending than those of distillate marine fuel.

The verification of PWR-fuel code for PWR in-core fuel management

International Nuclear Information System (INIS)

Surian Pinem; Tagor M Sembiring; Tukiran

2015-01-01

In-core fuel management for PWR is not easy because of the number of fuel assemblies in the core as much as 192 assemblies so many possibilities for placement of the fuel in the core. Configuration of fuel assemblies in the core must be precise and accurate so that the reactor operates safely and economically. It is necessary for verification of PWR-FUEL code that will be used in-core fuel management for PWR. PWR-FUEL code based on neutron transport theory and solved with the approach of multi-dimensional nodal diffusion method many groups and diffusion finite difference method (FDM). The goal is to check whether the program works fine, especially for the design and in-core fuel management for PWR. Verification is done with equilibrium core search model at three conditions that boron free, 1000 ppm boron concentration and critical boron concentration. The result of the average burn up fuel assemblies distribution and power distribution at BOC and EOC showed a consistent trend where the fuel with high power at BOC will produce a high burn up in the EOC. On the core without boron is obtained a high multiplication factor because absence of boron in the core and the effect of fission products on the core around 3.8 %. Reactivity effect at 1000 ppm boron solution of BOC and EOC is 6.44 % and 1.703 % respectively. Distribution neutron flux and power density using NODAL and FDM methods have the same result. The results show that the verification PWR-FUEL code work properly, especially for core design and in-core fuel management for PWR. (author)

Effect of fission yield libraries on the irradiated fuel composition in Monte Carlo depletion calculations

International Nuclear Information System (INIS)

Mitenkova, E.; Novikov, N.

2014-01-01

Improving the prediction of radiation parameters and reliability of fuel behaviour under different irradiation modes is particularly relevant for new fuel compositions, including recycled nuclear fuel. For fast reactors there is a strong dependence of nuclide accumulations on the nuclear data libraries. The effect of fission yield libraries on irradiated fuel is studied in MONTEBURNS-MCNP5-ORIGEN2 calculations of sodium fast reactors. Fission yield libraries are generated for sodium fast reactors with MOX fuel, using ENDF/B-VII.0, JEFF3.1, original library FY-Koldobsky, and GEFY 3.3 as sources. The transport libraries are generated from ENDF/B-VII.0 and JEFF-3.1. Analysis of irradiated MOX fuel using different fission yield libraries demonstrates the considerable spread in concentrations of fission products. The discrepancies in concentrations of inert gases being ∼25%, up to 5 times for stable and long-life nuclides, and up to 10 orders of magnitude for short-lived nuclides. (authors)

In situ metal ion contamination and the effects on proton exchange membrane fuel cell performance

Science.gov (United States)

Sulek, Mark; Adams, Jim; Kaberline, Steve; Ricketts, Mark; Waldecker, James R.

Automotive fuel cell technology has made considerable progress, and hydrogen fuel cell vehicles are regarded as a possible long-term solution to reduce carbon dioxide emissions, reduce fossil fuel dependency and increase energy efficiency. Even though great strides have been made, durability is still an issue. One key challenge is controlling MEA contamination. Metal ion contamination within the membrane and the effects on fuel cell performance were investigated. Given the possible benefits of using stainless steel or aluminum for balance-of-plant components or bipolar plates, cations of Al, Fe, Ni and Cr were studied. Membranes were immersed in metal sulfide solutions of varying concentration and then assembled into fuel cell MEAs tested in situ. The ranking of the four transition metals tested in terms of the greatest reduction in fuel cell performance was: Al 3+ ≫ Fe 2+ > Ni 2+, Cr 3+. For iron-contaminated membranes, no change in cell performance was detected until the membrane conductivity loss was greater than approximately 15%.

A dynamic programming approach for modeling low-carbon fuel technology adoption considering learning-by-doing effect

International Nuclear Information System (INIS)

Chen, Yuche; Zhang, Yunteng; Fan, Yueyue; Hu, Kejia; Zhao, Jianyou

2017-01-01

Highlights: • Dynamic programming method is used in transportation fuel portfolio planning. • The learning effect in new fuel technology is endogenously modeled through an experience curve. • Cellulosic biofuels play critical role in de-carbonization transport sector in near term. • The initial 3–4 billion gallons production is critical to bring down cellulosic biofuels’ cost. • Large penetration of Zero Emission Vehicles will discourage development of cellulosic biofuels. - Abstract: Promoting the adoption of low-carbon technologies in the transportation fuel portfolio is an effective strategy to mitigate greenhouse gas emissions from the transportation sector worldwide. However, as one of the most promising low-carbon fuels, cellulosic biofuel has not fully entered commercial production. Governments could provide guidance in developing cellulosic biofuel technologies, but no systematic approach has been proposed yet. We establish a dynamic programming framework for investigating time-dependent and adaptive decision-making processes to develop advanced fuel technologies. The learning-by-doing effect inherited in the technology development process is included in the framework. The proposed framework is applied in a case study to explore the most economical pathway for California to develop a solid cellulosic biofuel industry under its Low Carbon Fuel Standard. Our results show that cellulosic biofuel technology is playing a critical role in guaranteeing California’s 10% greenhouse gas emission reduction by 2020. Three to four billion gallons of cumulative production are needed to ensure that cellulosic biofuel is cost-competitive with petroleum-based fuels or conventional biofuels. Zero emission vehicle promoting policies will discourage the development of cellulosic biofuel. The proposed framework, with small adjustments, can also be applied to study new technology development in other energy sectors.

Network-based model for predicting the effect of fuel price on transit ridership and greenhouse gas emissions

Directory of Open Access Journals (Sweden)

Michael W. Levin

2017-12-01

Full Text Available As fuel prices increase, drivers may make travel choices to minimize not only travel time, but also fuel consumption. Consideration of fuel consumption would affect route choice and influence trip frequency and mode choice. For instance, travelers may elect to live closer to their workplace, or use public transit to avoid fuel consumption and the associated costs. To incorporate network characteristics into predictions of the effects of fuel prices, we develop a multi-class combined elastic demand, mode choice, and user equilibrium model using a generalized cost function of travel time and fuel consumption with a combined solution algorithm. The algorithm is implemented in a custom software package, and a case study application on the Austin, Texas network is presented. We evaluate the fuel-price sensitivity of key variables such as drive-alone and transit class proportions, person-miles traveled, link-level traffic flow and per capita fuel consumption and emissions. These effects are examined across a heterogeneous demand set, with multiple user-classes categorized based on their value of travel time. The highest relative transit elasticities against fuel price are observed among low value of time classes, as expected. Although total personal vehicle travel decreases, congestion increases on some roads due to the generalized cost function. Reductions in system-wide fuel consumption and greenhouse gas emissions are observed as well. The study uncovers the combined interactions among fuel prices, multi-modal choice behavior, travel performance, and resultant environmental impacts, all of which dictate the urban travel market. It also equips agencies with motivation to tailor emissions reduction and transit-ridership stimulus policies around the most responsive user classes.

Numerical and experimental investigation of the effect of geometry on combustion characteristics of solid-fuel ramjet

Science.gov (United States)

Gong, Lunkun; Chen, Xiong; Musa, Omer; Yang, Haitao; Zhou, Changsheng

2017-12-01

Numerical and experimental investigation on the solid-fuel ramjet was carried out to study the effect of geometry on combustion characteristics. The two-dimensional axisymmetric program developed in the present study adopted finite rate chemistry and second-order moment turbulence-chemistry models, together with k-ω shear stress transport (SST) turbulence model. Experimental data were obtained by burning cylindrical polyethylene using a connected pipe facility. The simulation results show that a fuel-rich zone near the solid fuel surface and an air-rich zone in the core exist in the chamber, and the chemical reactions occur mainly in the interface of this two regions; The physical reasons for the effect of geometry on regression rate is the variation of turbulent viscosity due to the geometry change. Port-to-inlet diameter ratio is the main parameter influencing the turbulent viscosity, and a linear relationship between port-to-inlet diameter and regression rate were obtained. The air mass flow rate and air-fuel ratio are the main influencing factors on ramjet performances. Based on the simulation results, the correlations between geometry and air-fuel ratio were obtained, and the effect of geometry on ramjet performances was analyzed according to the correlation. Three-dimensional regression rate contour obtained experimentally indicates that the regression rate which shows axisymmetric distribution due to the symmetry structure increases sharply, followed by slow decrease in axial direction. The radiation heat transfer in recirculation zone cannot be ignored. Compared with the experimental results, the deviations of calculated average regression rate and characteristic velocity are about 5%. Concerning the effect of geometry on air-fuel ratio, the deviations between experimental and theoretical results are less than 10%.

The effect of CO{sub 2} dissolved in a diesel fuel on the jet flame characteristics

Energy Technology Data Exchange (ETDEWEB)

Xiao Jin; Huang Zhen; Qiao Xinqi; Hou Yuchun [Shanghai Jiao Tong University, Shanghai (China). Research Institute of Internal Combustion Engine

2008-03-15

This paper is concerned with an experimental study of the jet diffusion flame characteristics of fuel containing CO{sub 2}. Using diesel fuel containing dissolved CO{sub 2} gas, experiments were performed under atmospheric conditions with a diesel hole-type nozzle of 0.19 mm orifice diameter at constant injection pressure. In this study, four different CO{sub 2} mass fraction in diesel fuel such as 3.13%, 7.18%, 12.33% and 17.82% were used to study the effect of CO{sub 2} concentration on the jet flame characteristics. Jet flame characteristics were measured by direct photography, meanwhile the image colorimetry is used to assess the qualitative features of jet flame temperature. Experimental results show that the CO{sub 2} gas dilution effect and the atomization effect have a great influence on the flame structure and average temperature. When the injection pressure of diesel fuel increased from 4 MPa to 6 MPa, the low temperature flame length increased from 18.4 cm to 21.7 cm and the full temperature flame length decreased from 147.6 cm to 134.7 cm. With the increase of CO{sub 2} gas dissolved in the diesel fuel, the jet flame full length decreased for the jet atomization being improved greatly meanwhile the low temperature flame length increased for the CO{sub 2} gas dilution effect; with the increase of CO{sub 2} gas dissolved in the diesel fuel, the average temperature of flame increases firstly and then falls. Experimental results validate that higher injection pressure will improve jet atomization and then increased the flame average temperature. 27 refs., 13 figs.

The effects of fission gas release on PWR fuel rod design and performance

International Nuclear Information System (INIS)

Leech, W.J.; Kaiser, R.S.

1980-01-01

The purpose of this investigation was to determine the effects of fission gas release on PWR fuel rod design and performance. Empirical models were developed from fission gas release data. Fission gas release during normal operation is a function of burnup. There is little additional fission gas release during anticipated transients. The empirical models were used to evaluate Westinghouse fuel rod designs. It was determined that fission gas release is not a limiting parameter for obtaining rod average burnups in the range of 50,000 to 60,000 MWD/MTU. Fission gas release during anticipated transients has a negligible effect on the margins to rod design limits. (author)

EFFECT OF COMPOSITION OF FUEL CONTAINING BUTANOL ON WORKING PROCESS PARAMETERS OF DIESEL ENGINE

Directory of Open Access Journals (Sweden)

D. G. Hershan

2017-01-01

Full Text Available Computational researches the effect of composition of fuel containing butanol on working process parameters of 4ЧН 11/12,5 diesel engine on the external speed characteristic have been conducted. Nominal power is 140 kW at engine speed 2300 min–1. The engine is equipped with gas turbine pressure charging with intercooling of charging air, accumulator-type fuel-handling system. Calculations of the working process have been made in accordance with the developed computer program and models. Investigations have been carried out in two stages: without any changes in regulation of fuel-handling system and with cyclic fuel delivery that ensure such value of excess air factor at various operational modes which corresponds to the operation with diesel fuel. All the obtained results have been analyzed in the paper. The paper shows changes in mean indicated pressure, specific indicated fuel consumption, indicated efficiency, specific nitrogen oxides emissions for various modes in question while using 5, 10, 15, 20, 25 and 30 % mixture of diesel fuel with butanol. Dependences of parameters pertaining to diesel operation have been determined according to external speed characteristic for various mixtures and the obtained data make it possible to justify parameters of the fuel-handling system. It has been recommended to use a diesel fuel-butanol mixture containing 15 % of butanol without any changes in regulating and design engine parameters. It has been revealed that in order to improve parameters of the engine operational process mixture composition must be changed while changing the operational mode. An injector nozzle with a compound needle for the fuel-handling system has been developed and it allows to change fuel composition according to engine operational mode.

Effects of Fuel Quantity on Soot Formation Process for Biomass-Based Renewable Diesel Fuel Combustion

KAUST Repository

Jing, Wei; Wu, Zengyang; Roberts, William L.; Fang, Tiegang

2016-01-01

Soot formation process was investigated for biomass-based renewable diesel fuel, such as biomass to liquid (BTL), and conventional diesel combustion under varied fuel quantities injected into a constant volume combustion chamber. Soot measurement

Fuel treatment effectiveness in forests of the upper Atlantic Coastal Plain—an evaluation at two spatial scales

Science.gov (United States)

Roger D. Ottmar; Susan J. Prichard

2012-01-01

Fuel treatment effectiveness in Southern forests has been demonstrated using fire behavior modeling and observations of reduced wildfire area and tree damage. However, assessments of treatment effectiveness may be improved with a more rigorous accounting of the fuel characteristics. We present two case studies to introduce a relatively new approach to characterizing...

Kinetic parameters of a material test research reactor fueled with various low enriched uranium dispersion fuels

International Nuclear Information System (INIS)

Muhammad, Farhan; Majid, Asad

2009-01-01

The effects of using different low enriched uranium fuels, having same uranium density, on the kinetic parameters of a material test research reactor were studied. For this purpose, the original aluminide fuel (UAl x -Al) containing 4.40 gU/cm 3 of an MTR was replaced with silicide (U 3 Si-Al and U 3 Si 2 -Al) and oxide (U 3 O 8 -Al) dispersion fuels having the same uranium density as of the original fuel. Simulations were carried out to calculate prompt neutron generation time, effective delayed-neutron fraction, core excess reactivity and neutron flux spectrum. Nuclear reactor analysis codes including WIMS-D4 and CITATION were used to carry out these calculations. It was observed that both the silicide fuels had the same prompt neutron generation time 0.02% more than that of the original aluminide fuel, while the oxide fuel had a prompt neutron generation time 0.05% less than that of the original aluminide fuel. The effective delayed-neutron fraction decreased for all the fuels; the decrease was maximum at 0.06% for U 3 Si 2 -Al followed by 0.03% for U 3 Si-Al, and 0.01% for U 3 O 8 -Al fuel. The U 3 O 8 -Al fueled reactor gave the maximum ρ excess at BOL which was 21.67% more than the original fuel followed by U 3 Si-Al which was 2.55% more, while that of U 3 Si 2 -Al was 2.50% more than the original UAl x -Al fuel. The neutron flux of all the fuels was more thermalized, than in the original fuel, in the active fuel region of the core. The thermalization was maximum for U 3 O 8 -Al followed by U 3 Si-Al and then U 3 Si 2 -Al fuel.

Investigation of Reactivity Feedback Mechanism of Axial and Radial Expansion Effect of Metal-Fueled Sodium-Cooled Fast Reactor

International Nuclear Information System (INIS)

Seong, Seung-Hwan; Choi, Chi-Woong; Jeong, Tae-Kyung; Ha, Gi-Seok

2015-01-01

The major inherent reactivity feedback models for a ceramic fuel used in a conventional light water reactor are Doppler feedback and moderator feedback. The metal fuel has these two reactivity feedback mechanisms previously mentioned. In addition, the metal fuel has two more reactivity feedback models related to the thermal expansion phenomena of the metal fuel. Since the metal fuel has a good capability to expand according to the temperature changes of the core, two more feedback mechanisms exist. These additional two feedback mechanism are important to the inherent safety of metal fuel and can make metal-fueled SFR safer than oxide-fueled SFR. These phenomena have already been applied to safety analysis on design extended condition. In this study, the effect of these characteristics on power control capability was examined through a simple load change operation. The axial expansion mechanism is induced from the change of the fuel temperature according to the change of the power level of PGSFR. When the power increases, the fuel temperatures in the metal fuel will increase and then the reactivity will decrease due to the axial elongation of the metal fuel. To evaluate the expansion effect, 2 cases were simulated with the same scenario by using MMS-LMR code developed at KAERI. The first simulation was to analyze the change of the reactor power according to the change of BOP power without the reactivity feedback model of the axial and radial expansion of the core during the power transient event. That is to say, the core had only two reactivity feedback mechanism of Doppler and coolant temperature

Effect of process parameters on the dynamic behavior of polymer electrolyte membrane fuel cells for electric vehicle applications

Directory of Open Access Journals (Sweden)

A.A. Abd El Monem

2014-03-01

Full Text Available This paper presents a dynamic mathematical model for Polymer Electrolyte Membrane “PEM” fuel cell systems to be used for electric vehicle applications. The performance of the fuel cell, depending on the developed model and taking the double layer charging effect into account, is investigated with different process parameters to evaluate their effect on the unit behavior. Thus, it will be easy to develop suitable controllers to regulate the unit operation, which encourages the use of fuel cells especially with electric vehicles applications. The steady-state performance of the fuel cell is verified using a comparison with datasheet data and curves provided by the manufacturer. The results and conclusions introduced in this paper provide a base for further investigation of fuel cells-driven dc motors for electric vehicle.

Simulation of a 250 kW diesel fuel processor/PEM fuel cell system

Science.gov (United States)

Amphlett, J. C.; Mann, R. F.; Peppley, B. A.; Roberge, P. R.; Rodrigues, A.; Salvador, J. P.

Polymer-electrolyte membrane (PEM) fuel cell systems offer a potential power source for utility and mobile applications. Practical fuel cell systems use fuel processors for the production of hydrogen-rich gas. Liquid fuels, such as diesel or other related fuels, are attractive options as feeds to a fuel processor. The generation of hydrogen gas for fuel cells, in most cases, becomes the crucial design issue with respect to weight and volume in these applications. Furthermore, these systems will require a gas clean-up system to insure that the fuel quality meets the demands of the cell anode. The endothermic nature of the reformer will have a significant affect on the overall system efficiency. The gas clean-up system may also significantly effect the overall heat balance. To optimize the performance of this integrated system, therefore, waste heat must be used effectively. Previously, we have concentrated on catalytic methanol-steam reforming. A model of a methanol steam reformer has been previously developed and has been used as the basis for a new, higher temperature model for liquid hydrocarbon fuels. Similarly, our fuel cell evaluation program previously led to the development of a steady-state electrochemical fuel cell model (SSEM). The hydrocarbon fuel processor model and the SSEM have now been incorporated in the development of a process simulation of a 250 kW diesel-fueled reformer/fuel cell system using a process simulator. The performance of this system has been investigated for a variety of operating conditions and a preliminary assessment of thermal integration issues has been carried out. This study demonstrates the application of a process simulation model as a design analysis tool for the development of a 250 kW fuel cell system.

Reforming options for hydrogen production from fossil fuels for PEM fuel cells

Energy Technology Data Exchange (ETDEWEB)

Ersoz, Atilla; Olgun, Hayati [TUBITAK Marmara Research Center, Institute of Energy, Gebze, 41470 Kocaeli (Turkey); Ozdogan, Sibel [Marmara University Faculty of Engineering, Goztepe, 81040 Istanbul (Turkey)

2006-03-09

PEM fuel cell systems are considered as a sustainable option for the future transport sector in the future. There is great interest in converting current hydrocarbon based transportation fuels into hydrogen rich gases acceptable by PEM fuel cells on-board of vehicles. In this paper, we compare the results of our simulation studies for 100kW PEM fuel cell systems utilizing three different major reforming technologies, namely steam reforming (SREF), partial oxidation (POX) and autothermal reforming (ATR). Natural gas, gasoline and diesel are the selected hydrocarbon fuels. It is desired to investigate the effect of the selected fuel reforming options on the overall fuel cell system efficiency, which depends on the fuel processing, PEM fuel cell and auxiliary system efficiencies. The Aspen-HYSYS 3.1 code has been used for simulation purposes. Process parameters of fuel preparation steps have been determined considering the limitations set by the catalysts and hydrocarbons involved. Results indicate that fuel properties, fuel processing system and its operation parameters, and PEM fuel cell characteristics all affect the overall system efficiencies. Steam reforming appears as the most efficient fuel preparation option for all investigated fuels. Natural gas with steam reforming shows the highest fuel cell system efficiency. Good heat integration within the fuel cell system is absolutely necessary to achieve acceptable overall system efficiencies. (author)

Reforming options for hydrogen production from fossil fuels for PEM fuel cells

Science.gov (United States)

Ersoz, Atilla; Olgun, Hayati; Ozdogan, Sibel

PEM fuel cell systems are considered as a sustainable option for the future transport sector in the future. There is great interest in converting current hydrocarbon based transportation fuels into hydrogen rich gases acceptable by PEM fuel cells on-board of vehicles. In this paper, we compare the results of our simulation studies for 100 kW PEM fuel cell systems utilizing three different major reforming technologies, namely steam reforming (SREF), partial oxidation (POX) and autothermal reforming (ATR). Natural gas, gasoline and diesel are the selected hydrocarbon fuels. It is desired to investigate the effect of the selected fuel reforming options on the overall fuel cell system efficiency, which depends on the fuel processing, PEM fuel cell and auxiliary system efficiencies. The Aspen-HYSYS 3.1 code has been used for simulation purposes. Process parameters of fuel preparation steps have been determined considering the limitations set by the catalysts and hydrocarbons involved. Results indicate that fuel properties, fuel processing system and its operation parameters, and PEM fuel cell characteristics all affect the overall system efficiencies. Steam reforming appears as the most efficient fuel preparation option for all investigated fuels. Natural gas with steam reforming shows the highest fuel cell system efficiency. Good heat integration within the fuel cell system is absolutely necessary to achieve acceptable overall system efficiencies.

Fuel behavior in advanced water reactors

International Nuclear Information System (INIS)

Bolme, A.B.

1996-01-01

Fuel rod behavior of advanced pressurized water reactors under steady state conditions has been investigated in this study. System-80+ and Westinghouse Vantage-5 fuels have been considered as advanced pressurized water reactor fuels to be analyzed. The purpose of this study is to analyze the sensitivity of ditferent models and the effect of selected design parameters on the overall fuel behavior. FRAPCON-II computer code has been used for the analyses. Different modelling options of FRAPCON-II have also been considered in these analyses. Analyses have been performed in two main parts. In the first part, effects of operating conditions on fuel behavior have been investigated. First, fuel rod response under normal operating conditions has been analyzed. Then, fuel rod response to different fuel ratings has been calculated. In the second part, in order to estimate the effect of design parameters on fuel behavior, parametric analyses have been performed. In this part, the effects of initial gap thickness, as fabricated fuel density, and initial fill gas pressure on fuel behavior have been analyzed. The computations showed that both of the fuel rods used in this study operate within the safety limits. However, FRAPCON-II modelling options have been resulted in different behavior due to their modelling characteristics. Hence, with the absence of experimental data, it is difficult to make assesment for the best fuel parameters. It is also difficult to estimate error associated with the results. To improve the performance of the code, it is necessary to develop better experimental correlations for material properties in order to analyze the eftect ot considerably different design parameters rather than nominal rod parameters

Effect of titania addition on the thermal conductivity of UO2 fuel [Paper IIIB-C

International Nuclear Information System (INIS)

Sengupta, A.K.; Kumar, A.; Arora, K.B.S.; Pandey, V.D.; Nair, M.R.; Kamath, H.S.

1986-01-01

Pellet clad interaction in nuclear reactor fuel elements can be reduced by the use of higher grain size UO 2 fuel. This is achieved by the addition of dopant like titania, niobia etc. However, these dopants are considered as impurities which may affect the thermophysical and thermomechanical properties of the fuel. Thermal Conductivity which is one of the important properties controlling the inpile performance of the fuel has been measured for pure UO 2 and UO 2 containing 0.05wt per cent and 0.1wt per cent TiO 2 in the temperature range 900K to 1900K in vacuum. Thermal conductivity was obtained from thermal diffusivity data measured by laser flash method. The paper highlights the experimental results and discusses the effect of TiO 2 on the thermal conductivity of UO 2 fuel. (author)

Effect of titania addition on the thermal conductivity of UO2 fuel (Paper IIIB-C)

Energy Technology Data Exchange (ETDEWEB)

Sengupta, A K; Kumar, A; Arora, K B.S.; Pandey, V D; Nair, M R; Kamath, H S

1986-01-01

Pellet clad interaction in nuclear reactor fuel elements can be reduced by the use of higher grain size UO2 fuel. This is achieved by the addition of dopant like titania, niobia etc. However, these dopants are considered as impurities which may affect the thermophysical and thermomechanical properties of the fuel. Thermal Conductivity which is one of the important properties controlling the inpile performance of the fuel has been measured for pure UO2 and UO2 containing 0.05wt per cent and 0.1wt per cent TiO2 in the temperature range 900K to 1900K in vacuum. Thermal conductivity was obtained from thermal diffusivity data measured by laser flash method. The paper highlights the experimental results and discusses the effect of TiO2 on the thermal conductivity of UO2 fuel. 5 figures.

The effect of dissolved hydrogen on the dissolution of {sup 233}U doped UO{sub 2}(s) high burn-up spent fuel and MOX fuel

Energy Technology Data Exchange (ETDEWEB)

Carbol, P. [Inst. for Transuranium Elements, Karlsruhe (Germany); Spahiu, K. (ed.) [and others

2005-03-01

In this report the results of the experimental work carried out in a large EU-research project (SFS, 2001-2004) on spent fuel stability in the presence of various amounts of near field hydrogen are presented. Studies of the dissolution of {sup 233}U doped UO{sub 2}(s) simulating 'old' spent fuel were carried out as static leaching tests, autoclave tests with various hydrogen concentrations and electrochemical tests. The results of the leaching behaviour of a high burn-up spent fuel pellet in 5 M NaCl solutions in the presence of 3.2 bar H{sub 2} pressure and of MOX fuel in dilute synthetic groundwater under 53 bar H{sub 2} pressure are also presented. In all the experimental studies carried out in this project, a considerable effect of hydrogen in the dissolution rates of radioactive materials was observed. The experimental results obtained in this project with a-doped UO{sub 2}, high burn-up spent fuel and MOX fuel together with literature data give a reliable background to use fractional alteration/dissolution rates for spent fuel of the order of 10{sup -6}/yr - 10{sup -8}/yr with a recommended value of 4x10{sup -7}/yr for dissolved hydrogen concentrations above 10{sup -3} M and Fe(II) concentrations typical for European repository concepts. Finally, based on a review of the experimental data and available literature data, potential mechanisms of the hydrogen effect are also discussed. The work reported in this document was performed as part of the Project SFS of the European Commission 5th Framework Programme under contract no FIKW-CT-2001-20192 SFS. It represents the deliverable D10 of the experimental work package 'Key experiments using a-doped UO{sub 2} and real spent fuel', coordinated by SKB with the participation of ITU, FZK-INE, ENRESA, CIEMAT, ARMINES-SUBATECH and SKB.

The effect of dissolved hydrogen on the dissolution of {sup 233}U doped UO{sub 2}(s) high burn-up spent fuel and MOX fuel

Energy Technology Data Exchange (ETDEWEB)

Carbol, P [Inst. for Transuranium Elements, Karlsruhe (Germany); Spahiu, K [and others

2005-03-01

In this report the results of the experimental work carried out in a large EU-research project (SFS, 2001-2004) on spent fuel stability in the presence of various amounts of near field hydrogen are presented. Studies of the dissolution of {sup 233}U doped UO{sub 2}(s) simulating 'old' spent fuel were carried out as static leaching tests, autoclave tests with various hydrogen concentrations and electrochemical tests. The results of the leaching behaviour of a high burn-up spent fuel pellet in 5 M NaCl solutions in the presence of 3.2 bar H{sub 2} pressure and of MOX fuel in dilute synthetic groundwater under 53 bar H{sub 2} pressure are also presented. In all the experimental studies carried out in this project, a considerable effect of hydrogen in the dissolution rates of radioactive materials was observed. The experimental results obtained in this project with a-doped UO{sub 2}, high burn-up spent fuel and MOX fuel together with literature data give a reliable background to use fractional alteration/dissolution rates for spent fuel of the order of 10{sup -6}/yr - 10{sup -8}/yr with a recommended value of 4x10{sup -7}/yr for dissolved hydrogen concentrations above 10{sup -3} M and Fe(II) concentrations typical for European repository concepts. Finally, based on a review of the experimental data and available literature data, potential mechanisms of the hydrogen effect are also discussed. The work reported in this document was performed as part of the Project SFS of the European Commission 5th Framework Programme under contract no FIKW-CT-2001-20192 SFS. It represents the deliverable D10 of the experimental work package 'Key experiments using a-doped UO{sub 2} and real spent fuel', coordinated by SKB with the participation of ITU, FZK-INE, ENRESA, CIEMAT, ARMINES-SUBATECH and SKB.

Agricultural transportation fuels

International Nuclear Information System (INIS)

Anon.

1993-01-01

The recommendations on the title subject are focused on the question whether advantages and disadvantages of agricultural fuels compared to fossil fuels justify the Dutch policy promotion of the use of agricultural products as basic materials for agricultural fuels. Attention is paid to energetic, environmental and economical aspects of both fuel types. Four options to apply agricultural transportation fuels are discussed: (1) 10% bio-ethanol in euro-unleaded gasoline for engines of passenger cars, equipped with a three-way catalyst; (2) the substitution of 15% methyl tertiair butyl ether (MTBE) by ethyl tertiair butyl ether (ETBE) as a substituent for lead in unleaded super plus gasoline (Sp 98) for engines of passenger cars, equipped with a three-way catalyst; (3) 50% KME (rapeseed oil ester) in low-sulfur diesel (0.05%S D) for engines of vans without a catalyst; and (4) the substitution of 0.05% S D by bio-ethanol or KME for buses with fuel-adjusted engines, equipped with a catalyst. Also the substitution by liquefied petroleum gas (LPG), compressed natural gas (CNG) or E 95 was investigated in option four. Each of the options investigated can contribute to a reduction of the use of fossil energy and the environmental effects of the use of fossil fuels, although some environmental effects from agricultural fuels must be taken into consideration. It is recommended to seriously pay attention to the promotion of agricultural fuels, not only in the Netherlands, but also in an international context. Policy instruments to be used in the stimulation of the use of such fuels are the existing European Community subsidies on fallow lands, exemption of the European Community energy levy, and the use of tax differentiation. Large-scale demonstration projects must be started to quantify hazardous emissions and to solve still existing technical problems. 8 figs., 3 tabs., refs., 4 appendices

Reducing the viscosity of Jojoba Methyl Ester diesel fuel and effects on diesel engine performance and roughness

Energy Technology Data Exchange (ETDEWEB)

Selim, Mohamed Y.E. [Mech. Eng. Dept., UAE University, Al-Ain, Abu Dhabi 17555 (United Arab Emirates)

2009-07-15

An experimental investigation has been carried out to test two approaches to reduce the viscosity of the Jojoba Methyl Ester (JME) diesel fuel. The first approach is the heating of the fuel to two temperatures of 50 and 70 C as compared to the base ambient temperature and to diesel fuel too. The second approach is adding one chemical which is considered by its own as alternative and renewable fuel which is Diethyl Ether (DEE). The viscosity has been reduced by both methods to close to diesel values. The performance of a diesel engine using those fuels has been tested in a variable compression research engine Ricardo E6 with the engine speed constant at 1200 rpm. The measured parameters included the exhaust gas temperature, the ignition delay period, the maximum pressure rise rate, maximum pressure, and indicated mean effective pressure and maximum heat release rate. The engine performance is presented and the effects of both approaches are scrutinized. (author)

Reducing the viscosity of Jojoba Methyl Ester diesel fuel and effects on diesel engine performance and roughness

International Nuclear Information System (INIS)

Selim, Mohamed Y.E.

2009-01-01

An experimental investigation has been carried out to test two approaches to reduce the viscosity of the Jojoba Methyl Ester (JME) diesel fuel. The first approach is the heating of the fuel to two temperatures of 50 and 70 deg. C as compared to the base ambient temperature and to diesel fuel too. The second approach is adding one chemical which is considered by its own as alternative and renewable fuel which is Diethyl Ether (DEE). The viscosity has been reduced by both methods to close to diesel values. The performance of a diesel engine using those fuels has been tested in a variable compression research engine Ricardo E6 with the engine speed constant at 1200 rpm. The measured parameters included the exhaust gas temperature, the ignition delay period, the maximum pressure rise rate, maximum pressure, and indicated mean effective pressure and maximum heat release rate. The engine performance is presented and the effects of both approaches are scrutinized.

A study of hydrogen isotopes fuel control by wall effect in magnetic fusion devices

Energy Technology Data Exchange (ETDEWEB)

Motevalli, S.M., E-mail: motavali@umz.ac.ir; Safari, M.

2016-11-15

Highlights: • A particle balance model for the main plasma and wall inventory in magnetic fusion device has been represented. • The dependence of incident particles energy on the wall has been considered in 10–300 eV for the sputtering yield and recycling coefficient. • The effect of fueling methods on plasma density behavior has been studied. - Abstract: Determination of plasma density behavior in magnetic confinement system needs to study the plasma materials interaction in the facing components such as first wall, limiter and divertor. Recycling of hydrogen isotope is an effective parameter in plasma density rate and plasma fueling. Recycling coefficient over the long pulse operation, gets to the unity, so it has a significant effect on steady state in magnetic fusion devices. Typically, sputtered carbon atoms from the plasma facing components form hydrocarbons and they redeposit on the wall. In this case little rate of hydrogen loss occurs. In present work a zero dimensional particle equilibrium model has been represented to determine particles density rate in main plasma and wall inventory under recycling effect and codeposition of hydrogen in case of continues and discontinues fueling methods and effective parameters on the main plasma decay has been studied.

Effects of operating conditions and fuel properties on emission performance and combustion efficiency of a swirling fluidized-bed combustor fired with a biomass fuel

International Nuclear Information System (INIS)

Kuprianov, Vladimir I.; Kaewklum, Rachadaporn; Chakritthakul, Songpol

2011-01-01

This work reports an experimental study on firing 80 kg/h rice husk in a swirling fluidized-bed combustor (SFBC) using an annular air distributor as the swirl generator. Two NO x emission control techniques were investigated in this work: (1) air staging of the combustion process, and (2) firing rice husk as moisturized fuel. In the first test series for the air-staged combustion, CO, NO and C x H y emissions and combustion efficiency were determined for burning 'as-received' rice husk at fixed excess air of 40%, while secondary-to-primary air ratio (SA/PA) was ranged from 0.26 to 0.75. The effects of SA/PA on CO and NO emissions from the combustor were found to be quite weak, whereas C x H y emissions exhibited an apparent influence of air staging. In the second test series, rice husks with the fuel-moisture content of 8.4% to 35% were fired at excess air varied from 20% to 80%, while the flow rate of secondary air was fixed. Radial and axial temperature and gas concentration (O 2 , CO, NO) profiles in the reactor, as well as CO and NO emissions, are discussed for the selected operating conditions. The temperature and gas concentration profiles for variable fuel quality exhibited significant effects of both fuel-moisture and excess air. As revealed by experimental results, the emission of NO from this SFBC can be substantially reduced through moisturizing rice husk, while CO is effectively mitigated by injection of secondary air into the bed splash zone, resulting in a rather low emission of CO and high (over 99%) combustion efficiency of the combustor for the ranges of operating conditions and fuel properties.

A method for determining an effective porosity correction factor for thermal conductivity in fast reactor uranium-plutonium oxide fuel pellets

International Nuclear Information System (INIS)

Inoue, Masaki; Abe, Kazuyuki; Sato, Isamu

2000-01-01

A reliable method has been developed for determining an effective porosity correction factor for calculating a realistic thermal conductivity for fast reactor uranium-plutonium (mixed) oxide fuel pellets. By using image analysis of the ceramographs of transverse sections of mixed-oxide fuel pellets, the fuel morphology could be classified into two basic types. One is a 'two-phase' type that consists of small pores dispersed in the fuel matrix. The other is a 'three-phase' type that has large pores in addition to the small pores dispersed in the fuel matrix. The pore sizes are divided into two categories, large and small, at the 30 μm area equivalent diameter. These classifications lead to an equation for calculating an effective porosity correction factor by accounting for the small and large pore volume fractions and coefficients. This new analytical method for determining the effective porosity correction factor for calculating the realistic thermal conductivity of mixed-oxide fuel was also experimentally confirmed for high-, medium- and low-density fuel pellets

DART model for irradiation-induced swelling of dispersion fuel elements including aluminum-fuel interaction

International Nuclear Information System (INIS)

Rest, J.; Hofman, G.L.

1997-01-01

The Dispersion Analysis Research Tool (DART) contains models for fission-gas-induced fuel swelling, interaction of fuel with the matrix aluminum, for the resultant reaction-product swelling, and for the calculation of the stress gradient within the fuel particle. The effects of an aluminide shell on fuel particle swelling are evaluated. Validation of the model is demonstrated by a comparison of DART calculations of fuel swelling of U 3 SiAl-Al and U 3 Si 2 -Al for various dispersion fuel element designs with the data

Fuel assembly, channel box of fuel assembly, fuel spacer of fuel assembly and method of manufacturing channel box

International Nuclear Information System (INIS)

Chaki, Masao; Kanazawa, Toru; Orii, Akihito; Nagayoshi, Takuji; Nishida, Koji; Kawasaki, Terufumi.

1997-01-01

In a fuel assembly of a BWR type reactor, fuel rods disposed at corners of side walls of a channel box or in the periphery of the side walls are partially removed, and recessed portions are formed on the side walls of the channel box from which the fuel rods are removed. Spaces closed at the sides are formed in the inner side of the corner portions. Openings are formed for communicating the closed space with the outside of the channel box. Then, the channel area of the outer side of the channel box is increased, through which much water flows to increase the amount of water in the reactor core thereby promoting the moderation of neutrons and providing thermal neutrons suitable to nuclear fission. The degree of freedom for distribution of the spaces in the reactor core is increased to improve neutron economy thereby enabling to utilize reactor fuels effectively. (N.H.)

Effects of water-emulsified fuel on a diesel engine generator's thermal efficiency and exhaust.

Science.gov (United States)

Syu, Jin-Yuan; Chang, Yuan-Yi; Tseng, Chao-Heng; Yan, Yeou-Lih; Chang, Yu-Min; Chen, Chih-Chieh; Lin, Wen-Yinn

2014-08-01

Water-emulsified diesel has proven itself as a technically sufficient improvement fuel to improve diesel engine fuel combustion emissions and engine performance. However, it has seldom been used in light-duty diesel engines. Therefore, this paper focuses on an investigation into the thermal efficiency and pollution emission analysis of a light-duty diesel engine generator fueled with different water content emulsified diesel fuels (WD, including WD-0, WD-5, WD-10, and WD-15). In this study, nitric oxide, carbon monoxide, hydrocarbons, and carbon dioxide were analyzed by a vehicle emission gas analyzer and the particle size and number concentration were measured by an electrical low-pressure impactor. In addition, engine loading and fuel consumption were also measured to calculate the thermal efficiency. Measurement results suggested that water-emulsified diesel was useful to improve the thermal efficiency and the exhaust emission of a diesel engine. Obviously, the thermal efficiency was increased about 1.2 to 19.9%. In addition, water-emulsified diesel leads to a significant reduction of nitric oxide emission (less by about 18.3 to 45.4%). However the particle number concentration emission might be increased if the loading of the generator becomes lower than or equal to 1800 W. In addition, exhaust particle size distributions were shifted toward larger particles at high loading. The consequence of this research proposed that the water-emulsified diesel was useful to improve the engine performance and some of exhaust emissions, especially the NO emission reduction. Implications: The accumulated test results provide a good basis to resolve the corresponding pollutants emitted from a light-duty diesel engine generator. By measuring and analyzing transforms of exhaust pollutant from this engine generator, the effects of water-emulsified diesel fuel and loading on emission characteristics might be more clear. Understanding reduction of pollutant emissions during the use

Fuel assembly and reactor core

International Nuclear Information System (INIS)

Aoyama, Motoo; Koyama, Jun-ichi; Uchikawa, Sadao; Bessho, Yasunori; Nakajima, Akiyoshi; Maruyama, Hiromi; Ozawa, Michihiro; Nakamura, Mitsuya.

1990-01-01

The present invention concerns fuel assemblies charged in a BWR type reactor and the reactor core. The fuel assembly comprises fuel rods containing burnable poisons and fuel rods not containing burnable poisons. Both of the highest and the lowest gadolinia concentrations of the fuel rods containing gadolinia as burnable poisons are present in the lower region of the fuel assembly. This can increase the spectral shift effect without increasing the maximum linear power density. (I.N.)

Long term storage effects of irradiated fuel elements on power distribution and reactivity

Energy Technology Data Exchange (ETDEWEB)

Ponzoni Filho, P.; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso T.I.C.; Fernandes Vanderlei Borba [FURNAS, Rio de Janeiro, RJ (Brazil); Fetterman, R.J. [Westinghouse Electric Corp., Pittsburgh, PA (United States)

1995-12-31

The ALPHA/PHOENIX-P/ANC (APA) code package was used to calculate the pin by pin power distribution and reactivity for Angra 1 Power Plant, Cycle 5. The Angra 1 Cycle 5 core was loaded with several irradiated fuel elements which were stored in the Spent Fuel Pool (SFP) for more than 8 years. Generally, neutronic codes take into account the buildup and depletion of just a few key fission, products such as Sm-149. In this paper it is shown that the buildup effects of other fission products must be considered for fuel which has been out of the core for significant periods of time. Impacts of these other fission products can change core reactivity and power distribution. (author). 3 refs, 4 figs, 4 tabs.

Long term storage effects of irradiated fuel elements on power distribution and reactivity

International Nuclear Information System (INIS)

Ponzoni Filho, P.; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso T.I.C.; Fernandes Vanderlei Borba; Fetterman, R.J.

1995-01-01

The ALPHA/PHOENIX-P/ANC (APA) code package was used to calculate the pin by pin power distribution and reactivity for Angra 1 Power Plant, Cycle 5. The Angra 1 Cycle 5 core was loaded with several irradiated fuel elements which were stored in the Spent Fuel Pool (SFP) for more than 8 years. Generally, neutronic codes take into account the buildup and depletion of just a few key fission, products such as Sm-149. In this paper it is shown that the buildup effects of other fission products must be considered for fuel which has been out of the core for significant periods of time. Impacts of these other fission products can change core reactivity and power distribution. (author). 3 refs, 4 figs, 4 tabs

Fuels Registration, Reporting, and Compliance Help

Science.gov (United States)

Information about the requirements for registration and health effects testing of new fuels or fuel additives and mandatory registration for fuels reporting and about mandatory reporting forms for parties regulated under EPA fuel programs.

Out-pile Test of Double Cladding Fuel Rod Mockups for a Nuclear Fuel Irradiation Test

Energy Technology Data Exchange (ETDEWEB)

Sohn, Jaemin; Park, Sungjae; Kang, Younghwan; Kim, Harkrho; Kim, Bonggoo; Kim, Youngki [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2008-05-15

An instrumented capsule for a nuclear fuel irradiation test has been developed to measure fuel characteristics, such as a fuel temperature, internal pressure of a fuel rod, a fuel pellet elongation and a neutron flux during an irradiation test at HANARO. In the future, nuclear fuel irradiation tests under a high temperature condition are expected from users. To prepare for this request, we have continued developing the technology for a high temperature nuclear fuel irradiation test at HANARO. The purpose of this paper is to verify the possibility that the temperature of a nuclear fuel can be controlled at a high temperature during an irradiation test. Therefore we designed and fabricated double cladding fuel rod mockups. And we performed out-pile tests using these mockups. The purposes of a out-pile test is to analyze an effect of a gap size, which is between an outer cladding and an inner cladding, on the temperature and the effect of a mixture ratio of helium gas and neon gas on the temperature. This paper presents the design and fabrication of double cladding fuel rod mockups and the results of the out-pile test.

Fuel consumption models for pine flatwoods fuel types in the southeastern United States

Science.gov (United States)

Clinton S. Wright

2013-01-01

Modeling fire effects, including terrestrial and atmospheric carbon fluxes and pollutant emissions during wildland fires, requires accurate predictions of fuel consumption. Empirical models were developed for predicting fuel consumption from fuel and environmental measurements on a series of operational prescribed fires in pine flatwoods ecosystems in the southeastern...

Hydraulic noise in reactor circuits and loops, and its effect on nuclear fuel vibration

International Nuclear Information System (INIS)

Card, D.C.

This paper reports the results of an investigation at WNRE to monitor noise levels in reactor circuits and loops, so as to characterize the systems and establish the importance of this noise on fuel and pressure tube vibration. Some of the techniques necessary for in-reactor installations of pressure transducers have been developed and measurements have been obtained in the vertical fuel channels of a very noisy out-reactor loop as well as in the WR-1 reactor circuits. A very quiet out-reactor loop has been constructed to study the vibration behaviour of 37-element fuel bundles in the horizontal CANDU pressurized-heavy water reactor systems. In this facility various types and levels of hydraulic noise are being generated to study their effect on the fuel bundles and flow tube at flow velocities up to approximately 13 m/s. (author)

The Effect of H2S on the Performance of SOFCs using Methane Containing Fuel

DEFF Research Database (Denmark)

Rasmussen, Jens Foldager Bregnballe; Hagen, Anke

2010-01-01

In recent years, the interest for using biogas derived from biomass as fuel in solid oxide fuel cells (SOFCs) has increased. To maximise the biogas to electrical energy output, it is important to study the effects of the main biogas components (CH4 and CO2), minor ones and traces (e.g. H2S...

Health Effects Associated with Inhalation Exposure to Diesel Emission Generated with and without CeO2 Nano Fuel Additive

Science.gov (United States)

Diesel exhaust (DE) exposure induces adverse cardiopulmonary effects. Addition of nano cerium (Ce) oxide additive to diesel fuel (DECe) increases fuel burning efficiency resulting in altered emission characteristics and potentially altered health effects. We hypothesized that inh...

Taxation on vehicle fuels: its impacts on switching to cleaner fuels

International Nuclear Information System (INIS)

Hung, W.-T.

2006-01-01

Vehicular consumption of fossil fuel contributes over 90% of air pollution in Hong Kong. A key strategy to improve Hong Kong's air quality is to discourage dirty fuels (e.g., leaded petrol and high-sulphur diesel) and to promote the use of clean fuels (e.g., low-sulphur diesel and liquefied petroleum gas (LPG)). This paper presents the empirical evidence on the effectiveness of the Government's clean fuel programs that offer tax subsidy to lower the consumption cost of such fuels. For the cases of unleaded petrol and ultra-low-sulphur diesel, lower fuel duties were offered so that the prices of these fuels were below those of leaded petrol and conventional diesel. Conventional petrol and diesel were phased out. In order to decide on the level of fuel duty concessions required to introduce LPG for taxis and bio-diesel for other vehicles, various Government-run trial programs were introduced to obtain cost estimates of using these alternative cleaner fuels. LPG using vehicles were subsequently exempted from the fuel duty in order to attract taxi and light bus operators to switch to LPG. It is apparent that the higher the subsidy, the faster is the rate at which switching to cleaner fuels takes place

Methanol as an alternative fuel: Economic and health effects

International Nuclear Information System (INIS)

Yuecel, M.K.

1991-01-01

Switching from gasoline to methanol fuels has important economic and health effects. Replacing gasoline with methanol will affect oil markets by lowering the demand for oil and thus lowering oil prices. Increased demand for the natural gas feedstock will increase natural gas prices. Because methanol is more costly than gasoline, fuel prices will also increase. On the other hand, methanol use will reduce ozone pollution and some of the health risks associated with gasoline. Considering all three markets affected by the phasing-out of gasoline, the switch to methanol results in net gains. The health benefits from lower pollution and the lives saved from the switch from gasoline to methanol are in addition to these gains. Overall, the benefits of the policy far outweigh the costs. However, the gains in the oil market, arising from the US monopsony power in the world oil market, can be captured by other, more efficient policies. 21 refs., 2 figs., 3 tabs

Environmental effects of fossil fuel combustion

International Nuclear Information System (INIS)

Chmielewski, A.G.

1999-01-01

Fossil fuel which include natural gas, petroleum, shale oil and bitumen are the main source of heat and electrical energy. All these fuels contain beside major constituents (carbon, hydrogen, oxygen) other materials as metal, sulfur and nitrogen compounds. During the combustion process different pollutants as fly ash, sulfur oxides (SO 2 and SO 3 ), nitrogen oxides (NO x NO + NO 2 ) and volatile organic compounds are emitted. Fly ash contain different trace elements (heavy metals). Gross emission of pollutants is tremendous all over the world. These pollutants are present in the atmosphere in such conditions that they can affect man and his environment. Air pollution caused by the particulate matter and other pollutants not only acts directly on environment but by contamination of water and soil leads to their degradation. Wet and dry deposition of inorganic pollutants leads to acidification of environment. These phenomena affect health of the people, increase corrosion, destroy cultivated soil and forests. Most of the plants, especially coniferous trees are not resistant to sulfur and nitrogen oxides. Following longer exposure leaves wither and fall. Widespread forest damage has been reported in Europe and North America regions. Many cultivated plants are not resistant to these pollutants either especially in the early period vegetation. The mechanisms of pollutants transformation in atmosphere are described by environmental chemistry. An important role in these transformations plays photochemistry. SO 2 and NO x are oxidized and sulfuric and nitric acids are formed in presence of water vapours, fog and droplets. Other problem discussed connected with human activities is emission of volatile organic compounds to the atmosphere. These emissions cause stratospheric ozone depletion, ground level photochemical ozone formation, toxic or carcinogenic human health effects, enhancing the global greenhouse effect, accumulation and persistence in environment. Wet flue gas

Environmental effects of fossil fuel combustion

Energy Technology Data Exchange (ETDEWEB)

Chmielewski, A G

1999-07-01

Fossil fuel which include natural gas, petroleum, shale oil and bitumen are the main source of heat and electrical energy. All these fuels contain beside major constituents (carbon, hydrogen, oxygen) other materials as metal, sulfur and nitrogen compounds. During the combustion process different pollutants as fly ash, sulfur oxides (SO{sub 2} and SO{sub 3}), nitrogen oxides (NO{sub x} NO + NO{sub 2}) and volatile organic compounds are emitted. Fly ash contain different trace elements (heavy metals). Gross emission of pollutants is tremendous all over the world. These pollutants are present in the atmosphere in such conditions that they can affect man and his environment. Air pollution caused by the particulate matter and other pollutants not only acts directly on environment but by contamination of water and soil leads to their degradation. Wet and dry deposition of inorganic pollutants leads to acidification of environment. These phenomena affect health of the people, increase corrosion, destroy cultivated soil and forests. Most of the plants, especially coniferous trees are not resistant to sulfur and nitrogen oxides. Following longer exposure leaves wither and fall. Widespread forest damage has been reported in Europe and North America regions. Many cultivated plants are not resistant to these pollutants either especially in the early period vegetation. The mechanisms of pollutants transformation in atmosphere are described by environmental chemistry. An important role in these transformations plays photochemistry. SO{sub 2} and NO{sub x} are oxidized and sulfuric and nitric acids are formed in presence of water vapours, fog and droplets. Other problem discussed connected with human activities is emission of volatile organic compounds to the atmosphere. These emissions cause stratospheric ozone depletion, ground level photochemical ozone formation, toxic or carcinogenic human health effects, enhancing the global greenhouse effect, accumulation and persistence in

Determination of the perturbing effect of the measuring device on thermal neutron distribution inside the fuel rod

Energy Technology Data Exchange (ETDEWEB)

Takac, S M; Krcevinac, S B [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

1966-07-15

The measurement of the thermal neutron distribution in an elementary cell of the reactor core is based on activating some of the existing detectors such as gold, copper, dysprosium, etc., inside the fuel rod and the corresponding part of the slowing-down medium. The techniques of measuring may be classified in two groups: - technique with detector foils, and - technique with a detector wire. The first group includes all experiments based on the so called 'tube technique'. By this technique the detector foils are arranged specifically in the tube by means of spacers and are positioned in a radially bored fuel rod. The 'spiral technique' is also included here. By this technique the fuel rod, which is first radially cut, is axially bored along the spiral and then detector foils inserted in the holes. The second group includes techniques according to which the detector wires may be positioned either in the radially bored hole through the fuel rod or in the spiral groove made in the horizontal cross-section in the fuel rod. To obtain higher resolution the detector wire after activation can be extruded, or before irradiation, spirally wound around a solid core and thus positioned in the radial hole in the fuel rod. In all cases the fuel region is perturbed either by the holes and the detector material, or by the holder of the detector foils. A number of authors have carried out these experiments under different geometrical and nuclear conditions, so obviously this perturbation had different effects on the results. So far the cell perturbation effects have not been discussed in the literature, neither this effect has been corrected in the final results. With respect to this a series of experiments for determining the micro distribution of thermal neutrons inside the fuel rod were made on the heavy-water natural-uranium system for different lattice pitches, with special stress or the investigation of the perturbing effects in the fuel rod which inevitably must be

Determination of the perturbing effect of the measuring device on thermal neutron distribution inside the fuel rod

International Nuclear Information System (INIS)

Takac, S.M.; Krcevinac, S.B.

1966-07-01

The measurement of the thermal neutron distribution in an elementary cell of the reactor core is based on activating some of the existing detectors such as gold, copper, dysprosium, etc., inside the fuel rod and the corresponding part of the slowing-down medium. The techniques of measuring may be classified in two groups: - technique with detector foils, and - technique with a detector wire. The first group includes all experiments based on the so called 'tube technique'. By this technique the detector foils are arranged specifically in the tube by means of spacers and are positioned in a radially bored fuel rod. The 'spiral technique' is also included here. By this technique the fuel rod, which is first radially cut, is axially bored along the spiral and then detector foils inserted in the holes. The second group includes techniques according to which the detector wires may be positioned either in the radially bored hole through the fuel rod or in the spiral groove made in the horizontal cross-section in the fuel rod. To obtain higher resolution the detector wire after activation can be extruded, or before irradiation, spirally wound around a solid core and thus positioned in the radial hole in the fuel rod. In all cases the fuel region is perturbed either by the holes and the detector material, or by the holder of the detector foils. A number of authors have carried out these experiments under different geometrical and nuclear conditions, so obviously this perturbation had different effects on the results. So far the cell perturbation effects have not been discussed in the literature, neither this effect has been corrected in the final results. With respect to this a series of experiments for determining the micro distribution of thermal neutrons inside the fuel rod were made on the heavy-water natural-uranium system for different lattice pitches, with special stress or the investigation of the perturbing effects in the fuel rod which inevitably must be

Effects of diluent admissions and intake air temperature in exhaust gas recirculation on the emissions of an indirect injection dual fuel engine

Energy Technology Data Exchange (ETDEWEB)

Abd-Alla, G.H.; Soliman, H.A.; Badr, O.A.; Abd-Rabbo, M.F. [Zagazig University, Cairo (Egypt). Shoubra Faculty of Engineering

2001-05-01

The operation of Diesel engines on gaseous fuels, commonly known as dual fuel engines, uses Diesel fuel as the pilot fuel and gaseous fuel (methane and sometimes propane in the present work) as the main fuel. The gaseous fuel was inducted in the intake manifold to mix with the intake air. The investigation was conducted on a high speed indirect injection (Ricardo-E6) dual fuel engine and was concerned with the effects of exhaust gas recirculation (EGR) on the dual fuel engine combustion and emissions, in particular, the effects of intake air temperature and diluent admissions (N{sub 2} and CO{sub 2}) on combustion and emissions. The use of diluents to displace oxygen (O{sub 2}) in the intake air resulted in a reduction in the O{sub 2} supplied to the engine, increased the inlet charge thermal capacity (thermal effect) and, potentially, CO{sub 2} and N{sub 2} participated in the combustion process (chemical effect). In a separate series of tests, the temperature of the engine inlet charge was raised gradually in order to simulate the effect of mixing hot EGR with the engine inlet gaseous fuel air mixture. It was found that the admission of diluents resulted in reductions in the exhaust oxides of nitrogen (NO{sub x}). Higher inlet charge temperature increases the exhaust NO{sub x} but reduces the unburned hydrocarbon emissions. Finally, when carbon dioxide was added to the inlet gaseous fuel air charge, large reductions in NO{sub x} were observed. (author)

Nuclear fuel assembly

International Nuclear Information System (INIS)

Hirano, Yasushi; Hirukawa, Koji; Sakurada, Koichi.

1994-01-01

A bundle of fuel rods is divided into four fuel rod group regions of small fuel rod bundles by a cross-shaped partitioning structure consisting of paired plate-like structures which connect two opposing surfaces of a channel box. A water removing material with less neutron absorption (for example, Zr or a Zr alloy) or a solid moderator is inserted and secured to a portion of a non-boiling water region interposed between the paired plate-like structure. It has a structure that light water flows to the region in the plate-like structure. The volume, density or composition of the water removing material is controlled depending on the composition of the fuels, to change the moderating characteristics of neutrons in the non-boiling water region. This can easily moderate the difference of nuclear characteristics between each of fuel assemblies using fuel materials of different fuel compositions. Further, the reactivity control effect of the burnable poisons can be enhanced without worsening fuel economy or linear power density. (I.N.)

Response of a direct methanol fuel cell to fuel change

Energy Technology Data Exchange (ETDEWEB)

Leo, T.J. [Dpto de Sistemas Oceanicos y Navales- ETSI Navales, Univ. Politecnica de Madrid, Avda Arco de la Victoria s/n, 28040 Madrid (Spain); Raso, M.A.; de la Blanca, E. Sanchez [Dpto de Quimica Fisica I- Fac. CC. Quimicas, Univ. Complutense de Madrid, Avda Complutense s/n, 28040 Madrid (Spain); Navarro, E.; Villanueva, M. [Dpto de Motopropulsion y Termofluidodinamica, ETSI Aeronauticos, Univ. Politecnica de Madrid, Pza Cardenal Cisneros 3, 28040 Madrid (Spain); Moreno, B. [Instituto de Ceramica y Vidrio, Consejo Superior de Investigaciones Cientificas, C/Kelsen 5, Campus de la UAM, 28049 Cantoblanco, Madrid (Spain)

2010-10-15

Methanol and ethanol have recently received much attention as liquid fuels particularly as alternative 'energy-vectors' for the future. In this sense, to find a direct alcohol fuel cell that able to interchange the fuel without losing performances in an appreciable way would represent an evident advantage in the field of portable applications. In this work, the response of a in-house direct methanol fuel cell (DMFC) to the change of fuel from methanol to ethanol and its behaviour at different ambient temperature values have been investigated. A corrosion study on materials suitable to fabricate the bipolar plates has been carried out and either 316- or 2205-duplex stainless steels have proved to be adequate for using in direct alcohol fuel cells. Polarization curves have been measured at different ambient temperature values, controlled by an experimental setup devised for this purpose. Data have been fitted to a model taking into account the temperature effect. For both fuels, methanol and ethanol, a linear dependence of adjustable parameters with temperature is obtained. Fuel cell performance comparison in terms of open circuit voltage, kinetic and resistance is established. (author)

Demonstration and evaluation of dual-fuel technology; Demonstration och utvaerdering av dual-fuel-tekniken

Energy Technology Data Exchange (ETDEWEB)

Staalhammar, Per; Erlandsson, Lennart; Willner, Kristina (AVL MTC Motortestcenter AB (Sweden)); Johannesson, Staffan (Ecoplan AB (Sweden))

2011-06-15

There is an increased interest for Dual Fuel (methane-Diesel) applications in Sweden since this technology is seen as one of the more interesting options for a fast and cost effective introduction of biomethane as fuel for HD engines. The Dual Fuel technology has been used for many years, mainly for stationary purpose (generators, pumps and ships) while the Spark Ignited (SI) 'Otto' technology has been used for trucks and busses. One obstacle for introducing Dual Fuel technology for busses and trucks is the EU legislation that don't allow for HD on road certification of Dual Fuel applications. Challenges with the Dual Fuel technology is to develop cost effective applications that is capable of reaching low emissions (especially CH{sub 4} and NO{sub x}) in combination with high Diesel replacement in the test cycles used for on road applications. AVL MTC Motortestcenter AB (hereinafter called AVL) has on commission by SGC (Swedish Gas technical Centre) carried out this project with the objectives to analyze the Dual Fuel (Diesel-methane) technology with focus on emissions, fuel consumption and technical challenges. One important part of this project was to carry out emission tests on selected Dual Fuel applications in Sweden and to compile experiences from existing Dual Fuel technology. This report also summarizes other commonly used technologies for methane engines and compares the Dual Fuel with conventional Diesel and Otto technologies. The major challenges with Dual Fuel applications for on road vehicles will be to develop robust and cost effective solutions that meet the emission legislations (with aged catalysts) and to increase the Diesel replacement to achieve reasonable reduction of green house gases (GHG). This is especially important when biomethane is available as fuel but not Bio-Diesel. It will probably be possible to reach EURO V emission limits with advanced Dual Fuel systems but none of the tested systems reached EURO V emission levels