Utilization of particle fuels in different reactor concepts

International Nuclear Information System (INIS)

1983-04-01

To date, particle fuel is only used in high temperature reactors (HTR). In this reactor type the particles exist of oxide fuel with a diameter of about 0.5 mm and are surrounded by various coatings in order to safely enclose fission products and decrease the radioactive release into the primary circuit. However, it is felt that fuel based upon spherical particles could have some advantages compared with pellets both on fabrication and in-core behaviour in several reactor concepts. This fuel is now of general interest and there is a high level of research and development activity in some countries. In order to collect, organize additional information and summarize experience on utilization of particle fuels in different reactor concepts, a questionnaire was prepared by IAEA in 1980 and sent to Member States, which might be involved in relevant developments. This survey has been prepared by a group of consultants and is mainly based on the responses to the IAEA questionnaire

Improved moulding material for addition to nuclear fuel particles to produce nuclear fuel elements

International Nuclear Information System (INIS)

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

1976-01-01

A suggestion is made to improve the moulding materials used to produce carbon-contained nuclear fuel particles by a coke-reducing added substance. The nuclear fuel particles are meant for the formation of fuel elements for gas-cooled high-temperature nuclear reactors. The moulding materials are above all for the formation of coated particles which are burnt in situ in nuclear fuel element chambers out of 'green' nuclear fuel bodies. The added substance improves the shape stability of the particles forming and prevents a stiding or bridge formation between the particles or with the surrounding walls. The following are named as added substances: 1) Polystyrene and styrene-butadiene-Co polymers (mol. wt. between 5oo and 1,000,000), 2) aromatic compounds (mol. wt. 75 to 300), 3) saturated hydrocarbon polymers (mol. wt. 5,000 to 1,000,000). Additional release agents further improve the properties in the same direction (e.g. alcohols, fatty acids, amines). (orig.) [de

Development of coated particle fuel technology

International Nuclear Information System (INIS)

Cho, Moonsung; Kim, B. G.; Kim, D. J.

2011-06-01

Ammonia contacting method for prehardenning the surfaces of ADU liquid droplets and the ageing/washing/drying method and equipment for spherical dried-ADU particles were improved and tested with laboratory sacle. After the improvement of fabrication process, the sphericity of UO 2 kernel obtained to 1.1, and the sintered density and O/U ratio of final UO 2 kernel were above 10.60g/cm 3 . 2.01 respectively. Defects of SiC coating layer could be minimized by optimization of gas flow rate. The fracture strength of SiC layer increased from 450 MPa to 530 MPa by controlling the coating defects. An effort was made to develop the fundamental technology for the fuel element compact for use in High Temperature Gas-cooled Reactor(HTGR) through an establishment of fabrication process, required materials and process equipment as well as performing experiments to identify the basic process conditions and optimize them. Thermal load simulation and verification experiments were carried out for an assesment of the design feasibility of the irradiation rod. Out-of-pile testing of irradiation device such as measurement of pressure drop and vibration, endurance test was performed and the validity of its design was confirmed. A fuel performance analysis code, COPA has been developed to calculate the fuel temperature, the failure fractions of coated fuel particles, the release of fission products. The COPA code can be used to evaluate the performance of the high temperature reactor fuel under the reactor operation, irradiation, heating conditions. KAERI participated in the round robin test of IAEA CRP-6 program to characterize the diameter, sphericity, coating thickness, density and anisotropy of coated particles provided by Korea, USA and South Africa. QC technology was established for TRISO-coated fuel particle. A method for accurate measurement of the optical anisotropy factor for PyC layers of coated particles was developed. Technology and inspection procedures for density

Impact on burnup performance of coated particle fuel design in pebble bed reactor with ROX fuel

International Nuclear Information System (INIS)

Ho, Hai Quan; Obara, Toru

2015-01-01

The pebble bed reactor (PBR), a kind of high-temperature gas-cooled reactor (HTGR), is expected to be among the next generation of nuclear reactors as it has excellent passive safety features, as well as online refueling and high thermal efficiency. Rock-like oxide (ROX) fuel has been studied at the Japan Atomic Energy Agency (JAEA) as a new once-through type fuel concept. Rock-like oxide used as fuel in a PBR can be expected to achieve high burnup and improve chemical stabilities. In the once-through fuel concept, the main challenge is to achieve as high a burnup as possible without failure of the spent fuel. The purpose of this study was to investigate the impact on burnup performance of different coated fuel particle (CFP) designs in a PBR with ROX fuel. In the study, the AGR-1 Coated Particle design and Deep-Burn Coated Particle design were used to make the burnup performance comparison. Criticality and core burnup calculations were performed by MCPBR code using the JENDL-4.0 library. Results at equilibrium showed that the two reactors utilizing AGR-1 Coated Particle and Deep-Burn Coated Particle designs could be critical with almost the same multiplication factor k eff . However, the power peaking factor and maximum power per fuel ball in the AGR-1 coated particle design was lower than that of Deep-Burn coated particle design. The AGR-1 design also showed an advantage in fissions per initial fissile atoms (FIFA); the AGR-1 coated particle design produced a higher FIFA than the Deep-Burn coated particle design. These results suggest that the difference in coated particle fuel design can have an effect on the burnup performance in ROX fuel. (author)

Improved graphite matrix for coated-particle fuel

International Nuclear Information System (INIS)

Schell, D.H.; Davidson, K.V.

1978-10-01

An experimental process was developed to incorporate coated fuel particles in an extruded graphite matrix. This structure, containing 41 vol% particles, had a high matrix density, >1.6 g/cm 3 , and a matrix conductivity three to four times that of a pitch-injected fuel rod at 1775 K. Experiments were conducted to determine the uniformity of particle loadings in extrusions. Irradiation specimens were supplied for five tests in the High-Fluence Isotope Reactor at the Oak Ridge National Laboratory

Critical Issues for Particle-Bed Reactor Fuels

Science.gov (United States)

Evans, Robert S.; Husser, Dewayne L.; Jensen, Russell R.; Kerr, John M.

1994-07-01

Particle-Bed Reactors (PBRs) potentially offer performance advantages for nuclear thermal propulsion, including very high power densities, thrust-to-weight ratios, and specific impulses. A key factor in achieving all of these is the development of a very-high-temperature fuel. The critical issues for all such PBR fuels are uranium loading, thermomechanical and thermochemical stability, compatibility with contacting materials, fission product retention, manufacturability, and operational tolerance for particle failures. Each issue is discussed with respect to its importance to PBR operation, its status among current fuels, and additional development needs. Mixed-carbide-based fuels are recommended for further development to support high-performance PBRs.

SP-100 coated-particle fuel development. Phase I. Final report

International Nuclear Information System (INIS)

1983-03-01

This document is the final report of Phase I of the SP-100 Coated-Particle Fuel Development Program conducted by GA Technologies Inc. for the US Department of Energy under contract DE-AT03-82SF11690. The general objective of the study conducted between September and December 1982 was to evaluate coated-particle type fuel as an alternate or backup fuel to the UO 2 tile-and-fin arrangement currently incorporated into the reference design of the SP-100 reactor core. This report presents and discusses the following topics in the order listed: the need for an alternative fuel for the SP-100 nuclear reactor; an abbreviated description of the reference and coated-particle fuel module concepts; the bases and results of the study and analysis leading to the preliminary design of a coated particle suitable for the SP-100 space power reactor; incorporation of the fuel particles into compacts and heat-pipe-cooled modules; initial efforts and plans to fabricate coated-particle fuel and fuel compacts; the design and performance of the proposed alternative core relative that of the reference fuel; and a summary of critical issues and conclusions consistent with the level of effort and duration of the study

Physicochemical analysis of interaction of oxide fuel with pyrocarbon coatings of fuel particles

International Nuclear Information System (INIS)

Lyutikov, R.A.; Khromov, Yu.F.; Chernikov, A.S.

1990-01-01

Equilibrium pressure of (CO+Kr,Xe) gases inside fuel particle with oxide kern depending on design features of fuel particle, on temperature. on (O/U) initial composition and fuel burnup is calculated using the suggested model. Analysis of possibility for gas pressure reduction by means of uranium carbide alloying of kern and degree increase of solid fission product retention (Cs for example) during alumosilicate alloying of uranium oxide is conducted

Development of Coated Particle Fuel Technology

International Nuclear Information System (INIS)

Cho, Moon Sung; Kim, B. G.; Kim, Y. K.

2009-04-01

UO 2 kernel fabrication technology was developed at the lab sacle(20∼30g-UO 2 /batch). The GSP technique, modified method of sol-gel process, was used in the preparation of spherical ADU gel particle and these particles were converted to UO 3 and UO 2 phases in calcination furnace and sintering furnace respectively. Based on the process variables optimized using simulant kernels in 1-2 inch beds, SiC TRISO-coated particles were fabricated using UO 2 kernel. Power densities of TRISO coated particle fuels and gamma heat of the tubes are calculated as functions of vertical location of the fuel specimen in the irradiation holes by using core physics codes, MCNP and Helios. A finite model was developed for the calculations of temperatures and stresses of the specimen and the irradiation tubes. Dimensions of the test tubes are determined based on the temperatures and stresses as well as the gamma heat generated at the given condition. 9 modules of the COPA code (MECH, FAIL, TEMTR, TEMBL, TEMPEB, FPREL, MPRO, BURN, ABAQ), the MECH, FAIL, TEMTR, TEMBL, TEMPEB, and FPREL were developed. The COPA-FPREL was verified through IAEA CRP-6 accident benchmarking problems. KAERI participated in the round robin test of IAEA CRP-6 program to characterize the diameter, sphericity, coating thickness, density and anisotropy of coated particles provided by Korea, USA and South Africa. The inspection and test plan describing specifications and inspection method of coated particles was developed to confirm the quality standard of coated particles. The quality inspection instructions were developed for the inspection of coated particles by particle size analyzer, density inspection of coating layers by density gradient column, coating thickness inspection by X-ray, and inspection of optical anistropy factor of PyC layer. The quality control system for the TRISO-coated particle fuel was derived based on the status of quality control systems of other countries

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

Silver release from coated particle fuel

International Nuclear Information System (INIS)

Brown, P.E.; Nabielek, H.

1977-03-01

The fission product Ag-110 m released from coated particles can be the dominant source of radioactivity from the core of a high temperature reactor in the early stages of the reactor life and possibly limits the accessability of primary circuit components. It can be shown that silver is retained in oxide fuel by a diffusion process (but not in carbide or carbon-diluted fuel) and that silver is released through all types of pyrocarbon layers. The retention in TRISO particles is variable and seems to be mainly connected with operating temperature and silicon carbide quality. (orig.) [de

Advances in Automated QA/QC for TRISO Fuel Particle Production

International Nuclear Information System (INIS)

Hockey, Ronald L.; Bond, Leonard J.; Batishko, Charles R.; Gray, Joseph N.; Saurwein, John J.; Lowden, Richard A.

2004-01-01

Fuel in most Generation IV reactor designs typically encompasses billions of the TRISO particles. Present day QA/QC methods, done manually and in many cases destructively, cannot economically test a statistically significant fraction of the large number of the individual fuel particles required. Fully automated inspection technologies are essential to economical TRISO fuel particle production. A combination of in-line nondestructive (NDE) measurements employing electromagnetic induction and digital optical imaging analysis is currently under investigation and preliminary data indicate the potential for meeting the demands of this application. To calibrate high-speed NDE methods, surrogate fuel particle samples are being coated with layers containing a wide array of defect types found to degrade fuel performance and these are being characterized via high-resolution CT and digital radiographic images

Selenium fuel: Surface engineering of U(Mo) particles to optimise fuel performance

International Nuclear Information System (INIS)

Van den Berghe, S.; Leenaers, A.; Detavernier, C.

2010-01-01

Recent developments on the stabilisation of U(Mo) in-pile behaviour in plate-type fuel have focussed almost exclusively on the addition of Si to the Al matrix of the fuel. This has now culminated in a qualification effort in the form of the European LEONIDAS initiative for which irradiations will start in 2010. In this framework, many discussions have been held on the Si content of the matrix needed for stabilisation of the interaction phase and the requirement for the formation of Si-rich layers around the particles during the fabrication steps. However, it is clear that the Si needs to be incorporated in the interaction phase for it to be effective, for which the currently proposed methods depend on a diffusion mechanism, which is difficult to control. This has lead to the concept of a Si coated particle as a more efficient way of incorporating the Si in the fuel by putting it immediately where it will be required : at the fuel-matrix interface. As part of the SELENIUM (Surface Engineered Low ENrIched Uranium-Molybdenum fuel) project, SCK CEN has built a sputter coater for PVD magnetron sputter coating of particles in collaboration with the University of Ghent. The coater is equipped with three 3 inch magnetron sputter heads, allowing deposition of 3 different elements or a single element at high deposition speed. The particles are slowly rotated in a drum to produce homogeneous layer thicknesses. (author)

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)

Performance evaluation of large U-Mo particle dispersed fuel irradiated in HANARO

International Nuclear Information System (INIS)

Ryu, Ho Jin; Park, Jong Man; Oh, Seok Jin; Jang, Se Jung; Yu, Byung Ok; Lee, Choong Seong; Seo, Chul Gyo; Chae, Hee Taek; Kim, Chang Kyu

2008-01-01

U-Mo/Al dispersion fuel is being developed as advanced fuel for research reactors. Irradiation behavior of U-Mo/Al dispersion fuel has been studied to evaluate its fuel performance. One of the performance limiting factors is a chemical interaction between the U-Mo particle and the Al matrix because the thermal conductivity of fuel meat is decreased with the interaction layer growth. In order to overcome the interaction problem, large-sized U-Mo particles were fabricated by controlling the centrifugal atomization conditions. The fuel performance behavior of U-Mo/Al dispersion fuel was estimated by using empirical models formulated based on the microstructural analyses of the post-irradiation examination (PIE) on U-Mo/Al dispersion fuel irradiated in HANARO reactor. Temperature histories of U-Mo/Al dispersion fuel during irradiation tests were estimated by considering the effect of an interaction layer growth on the thermal conductivity of the fuel meat. When the fuel performances of the dispersion fuel rods containing U-Mo particles with various sizes were compared, fuel temperature was decreased as the average U-Mo particle size was increases. It was found that the dispersion of a larger U-Mo particle was effective for mitigating the thermal degradation which is associated with an interaction layer growth. (author)

Behaviour of HTGR coated fuel particles at high-temperature tests

International Nuclear Information System (INIS)

Chernikov, A.S.; Lyutikov, R.A.; Kurbakov, S.D.; Repnikov, V.M.; Khromonozhkin, V.V.; Soloviyov, G.I.

1990-01-01

At the temperature range 1200-2600 deg. C prereactor tests of TRISO fuel particles on the base of UO 2 , UC x O y and UO 2 +2Al 2 O 3 . SiO 2 kernels, and also fuel particle models with ZrC kernels were performed. Isothermal annealings carried out at temperatures of 1400-2600 deg. C, thermogradient ones at 1200-2200 deg. C (Δ T = 200-1200 deg. C/cm). It is shown that at heating to 2200 deg. C integrity of fuel particles is limited by different thermal expansion of PyC and SiC coatings, and also by thermal dissociation of SiC. At higher temperatures the failure is caused by development of high pressures within weakened fuel particles. It is found that uranium migration from alloyed fuel (UC x O y , UO 2 +2Al 2 O 3 .SiO 2 ) in the process of annealing is higher than that from UO 2 . (author)

Coated particle fuel for high temperature gas cooled reactors

Energy Technology Data Exchange (ETDEWEB)

Verfondern, Karl; Nabielek, Heinz [Research Center Julich (FZJ), Julich (Germany); Kendall, James M. [Global Virtual L1c, Prescott (United States)

2007-10-15

Roy Huddle, having invented the coated particle in Harwell 1957, stated in the early 1970s that we know now everything about particles and coatings and should be going over to deal with other problems. This was on the occasion of the Dragon fuel performance information meeting London 1973: How wrong a genius be{exclamation_point} It took until 1978 that really good particles were made in Germany, then during the Japanese HTTR production in the 1990s and finally the Chinese 2000-2001 campaign for HTR-10. Here, we present a review of history and present status. Today, good fuel is measured by different standards from the seventies: where 9 x 10{sup -4} initial free heavy metal fraction was typical for early AVR carbide fuel and 3 x 10{sup -4} initial free heavy metal fraction was acceptable for oxide fuel in THTR, we insist on values more than an order of magnitude below this value today. Half a percent of particle failure at the end-of-irradiation, another ancient standard, is not even acceptable today, even for the most severe accidents. While legislation and licensing has not changed, one of the reasons we insist on these improvements is the preference for passive systems rather than active controls of earlier times. After renewed HTGR interest, we are reporting about the start of new or reactivated coated particle work in several parts of the world, considering the aspects of designs/traditional and new materials, manufacturing technologies/ quality control/ quality assurance, irradiation and accident performance, modeling and performance predictions, and fuel cycle aspects and spent fuel treatment. In very general terms, the coated particle should be strong, reliable, retentive, and affordable. These properties have to be quantified and will be eventually optimized for a specific application system. Results obtained so far indicate that the same particle can be used for steam cycle applications with 700-750 .deg. C helium coolant gas exit, for gas turbine

Coated particle fuel for high temperature gas cooled reactors

International Nuclear Information System (INIS)

Verfondern, Karl; Nabielek, Heinz; Kendall, James M.

2007-01-01

Roy Huddle, having invented the coated particle in Harwell 1957, stated in the early 1970s that we know now everything about particles and coatings and should be going over to deal with other problems. This was on the occasion of the Dragon fuel performance information meeting London 1973: How wrong a genius be! It took until 1978 that really good particles were made in Germany, then during the Japanese HTTR production in the 1990s and finally the Chinese 2000-2001 campaign for HTR-10. Here, we present a review of history and present status. Today, good fuel is measured by different standards from the seventies: where 9 x 10 -4 initial free heavy metal fraction was typical for early AVR carbide fuel and 3 x 10 -4 initial free heavy metal fraction was acceptable for oxide fuel in THTR, we insist on values more than an order of magnitude below this value today. Half a percent of particle failure at the end-of-irradiation, another ancient standard, is not even acceptable today, even for the most severe accidents. While legislation and licensing has not changed, one of the reasons we insist on these improvements is the preference for passive systems rather than active controls of earlier times. After renewed HTGR interest, we are reporting about the start of new or reactivated coated particle work in several parts of the world, considering the aspects of designs/traditional and new materials, manufacturing technologies/ quality control/ quality assurance, irradiation and accident performance, modeling and performance predictions, and fuel cycle aspects and spent fuel treatment. In very general terms, the coated particle should be strong, reliable, retentive, and affordable. These properties have to be quantified and will be eventually optimized for a specific application system. Results obtained so far indicate that the same particle can be used for steam cycle applications with 700-750 .deg. C helium coolant gas exit, for gas turbine applications at 850-900 .deg. C

Support vector machine to predict diesel engine performance and emission parameters fueled with nano-particles additive to diesel fuel

Science.gov (United States)

Ghanbari, M.; Najafi, G.; Ghobadian, B.; Mamat, R.; Noor, M. M.; Moosavian, A.

2015-12-01

This paper studies the use of adaptive Support Vector Machine (SVM) to predict the performance parameters and exhaust emissions of a diesel engine operating on nanodiesel blended fuels. In order to predict the engine parameters, the whole experimental data were randomly divided into training and testing data. For SVM modelling, different values for radial basis function (RBF) kernel width and penalty parameters (C) were considered and the optimum values were then found. The results demonstrate that SVM is capable of predicting the diesel engine performance and emissions. In the experimental step, Carbon nano tubes (CNT) (40, 80 and 120 ppm) and nano silver particles (40, 80 and 120 ppm) with nanostructure were prepared and added as additive to the diesel fuel. Six cylinders, four-stroke diesel engine was fuelled with these new blended fuels and operated at different engine speeds. Experimental test results indicated the fact that adding nano particles to diesel fuel, increased diesel engine power and torque output. For nano-diesel it was found that the brake specific fuel consumption (bsfc) was decreased compared to the net diesel fuel. The results proved that with increase of nano particles concentrations (from 40 ppm to 120 ppm) in diesel fuel, CO2 emission increased. CO emission in diesel fuel with nano-particles was lower significantly compared to pure diesel fuel. UHC emission with silver nano-diesel blended fuel decreased while with fuels that contains CNT nano particles increased. The trend of NOx emission was inverse compared to the UHC emission. With adding nano particles to the blended fuels, NOx increased compared to the net diesel fuel. The tests revealed that silver & CNT nano particles can be used as additive in diesel fuel to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

Adaptive neuro-fuzzy inference system (ANFIS) to predict CI engine parameters fueled with nano-particles additive to diesel fuel

Science.gov (United States)

Ghanbari, M.; Najafi, G.; Ghobadian, B.; Mamat, R.; Noor, M. M.; Moosavian, A.

2015-12-01

This paper studies the use of adaptive neuro-fuzzy inference system (ANFIS) to predict the performance parameters and exhaust emissions of a diesel engine operating on nanodiesel blended fuels. In order to predict the engine parameters, the whole experimental data were randomly divided into training and testing data. For ANFIS modelling, Gaussian curve membership function (gaussmf) and 200 training epochs (iteration) were found to be optimum choices for training process. The results demonstrate that ANFIS is capable of predicting the diesel engine performance and emissions. In the experimental step, Carbon nano tubes (CNT) (40, 80 and 120 ppm) and nano silver particles (40, 80 and 120 ppm) with nanostructure were prepared and added as additive to the diesel fuel. Six cylinders, four-stroke diesel engine was fuelled with these new blended fuels and operated at different engine speeds. Experimental test results indicated the fact that adding nano particles to diesel fuel, increased diesel engine power and torque output. For nano-diesel it was found that the brake specific fuel consumption (bsfc) was decreased compared to the net diesel fuel. The results proved that with increase of nano particles concentrations (from 40 ppm to 120 ppm) in diesel fuel, CO2 emission increased. CO emission in diesel fuel with nano-particles was lower significantly compared to pure diesel fuel. UHC emission with silver nano-diesel blended fuel decreased while with fuels that contains CNT nano particles increased. The trend of NOx emission was inverse compared to the UHC emission. With adding nano particles to the blended fuels, NOx increased compared to the net diesel fuel. The tests revealed that silver & CNT nano particles can be used as additive in diesel fuel to improve combustion of the fuel and reduce the exhaust emissions significantly.

Irradiation behaviors of coated fuel particles, (4)

International Nuclear Information System (INIS)

Fukuda, Kousaku; Kashimura, Satoru; Ogawa, Toru; Ikawa, Katsuichi; Iwamoto, Kazumi; Ishimoto, Kiyoshi

1981-09-01

Loose coated fuel particles prepared in confirmity to a preliminary design for the multi-purpose VHTR in fiscal 1972 - 1974 were irradiated by 73F - 12A capsule in JMTR. Main purpose for this irradiation experiment was to examine irradiation stability of the candidate TRISO coated fuel particles for the VHTR. Also the coated particles possessing low-density kernel (90%TD), highly anisotropic OLTI-PyC and ZrC coating layer were loaded with the candidate particles in this capsule. The coated particles were irradiated up to 1.5 x 10 21 n/cm 2 of fast neutron fluence (E > 0.18 MeV) and 3.2% FIMA of burnup. In the post irradiation examination it was observed that among three kinds of TRISO particles exposed to irradiation corresponding to the normal operating condition of the VHTR ones possessing poor characteristics of the coating layers did not show a good stability. The particles irradiated under abnormally high temperature condition (> 1800 0 C) revealed 6.7% of max. EOL failure fraction (95% confidence limit). Most of these particles were failed by the ameoba effect. Furthermore, among four kinds of the TRISO particles exposed to irradiation corresponding to the transient condition of the VHTR (--1500 0 C) the two showed a good stability, while the particles possessing highly anisotropic OLTI-PyC or poorly characteristic coating layers were not so good. (author)

Analytical Dancoff factor evaluations for reactor designs loaded with TRISO particle fuel

International Nuclear Information System (INIS)

Ji, Wei; Liang, Chao; Pusateri, Elise N.

2014-01-01

Highlights: • The Dancoff factors for randomly distributed TRISO fuel particles are evaluated. • A new “dual-sphere” model is proposed to predict Dancoff factors. • The new model accurately accounts for the coating regions of fuel particles. • High accuracy is achieved over a broad range of design parameters. • The new model can be used to analyze reactors with double heterogeneity. - Abstract: A new mathematical model, the dual-sphere model, is proposed to analytically evaluate Dancoff factors of TRISO fuel kernels based on the chord method. The accurate evaluation of fuel kernel Dancoff factors is needed when one analyzes nuclear reactors loaded with TRISO particle fuel. In these reactor designs, fuel kernels are randomly distributed and shield each other, causing a shadowing effect. The Dancoff factor is a quantitative measure of this effect and is determined by the spatial distribution of fuel kernels. A TRISO fuel particle usually consists of four layers that form a coating region outside the fuel kernel. When fuel particles are loaded in the reactor, the spatial distribution of fuel kernels can be affected by the thickness of the coating region. Therefore, the coating region should be taken into account in the calculation of Dancoff factors. However, the previous model, the single-sphere model, assumes no coating regions in the Dancoff factor predictions. To address this model deficiency, the dual-sphere model is proposed by deriving a new chord length distribution function between two fuel kernels that explicitly accounts for coating regions. The new model is employed to derive analytical solutions of infinite medium, intra-fuel pebble and intra-fuel compact/pin Dancoff factors over a wide range of volume packing fractions of TRISO fuel particles, varying from 2% to 60%. Comparisons are made with the predictions from the single-sphere model and reference Monte Carlo simulations. A significant improvement of the accuracy, over the ranges of

Fission product released experiment of coated fuel particles

Energy Technology Data Exchange (ETDEWEB)

Shijiang, Xu; Bing, Yang; Chunhe, Tang; Junguo, Zhu; Jintao, Huang; Binzhong, Zhang [Inst. of Nucl. Energy Technology, Tsinghua Univ., Beijing (China); Jinghan, Luo [Inst. of Atomic Energy, Beijing (China)

1992-01-15

Four samples of coated fuel particles were irradiated in the Heavy-Water Research Reactor of the Institute of Atomic Energy. Each of them was divided into two groups and irradiated to the burn up of 0.394% fima and 0.788% fima in two static capsules, respectively. After irradiation and cooling, post irradiation annealing experiment was carried out, the release ratios of the fission product {sup 133}Xe and {sup 131}I were measured, they are in the order of 10{sup -6}{approx}10{sup -7}. The fission product release ratio of naked kernel was also measured under the same conditions as for the coated fuel particles, the ratio of the fission product release of the coated fuel particles and of the naked kernel was in the order of 10{sup -5}{approx}10{sup -4}.

Factors affecting defective fraction of biso-coated HTGR fuel particles during in-block carbonization

International Nuclear Information System (INIS)

Caputo, A.J.; Johnson, D.R.; Bayne, C.K.

1977-01-01

The performance of Biso-coated thoria fuel particles during the in-block processing step of HTGR fuel element refabrication was evaluated. The effect of various process variables (heating rate, particle crushing strength, horizontal and/or vertical position in the fuel element blocks, and fuel hole permeability) on pitch coke yield, defective fraction of fuel particles, matrix structure, and matrix porosity was evaluated. Of the variables tested, only heating rate had a significant effect on pitch coke yield while both heating rate and particle crushing strength had a significant effect on defective fraction of fuel particles

Modeling of coated fuel particles irradiation behavior

International Nuclear Information System (INIS)

Liang Tongxiang; Phelip, M.

2006-01-01

In this report, PANAMA code was used to estimate the CP performance under normal and accident condition. Under the normal irradiation test (1000 degree C 625 efpd, 10% FIMA), for intact CP fuel, failure fraction is in the level of 10 -7 . As-fabricated SiC failed particles results in the through coatings failed particles much earlier than the intact particles does, OPyC layer does not fail immediately after irradiation starts. The significant failures start at beyond the burnup of about 7% FIMA. Under the accident condition, the calculated results showed that when the heating temperature is much higher than 1850 degree C, the failure fraction of coated particle can reach the level of 1 percent. The CP fuel fails significantly if it has a buffer layer thinner than 65 urn, SiC layer thinner than 30 μm. High burnup CP need to develop small size kernel, thick buffer layer and thick SiC layer. (authors)

Irradiation behaviors of coated fuel particles, (3)

International Nuclear Information System (INIS)

Fukuda, Kousaku; Kashimura, Satoru; Iwamoto, Kazumi; Ikawa, Katsuichi

1980-07-01

This report is concerning to the irradiation experiments of the coated fuel particles, which were performed by 72F-6A and 72F-7A capsules in JMTR. The coated particles referred to the preliminary design of VHTR were prepared for the experiments in 1972 and 1973. 72F-6A capsule was irradiated at G-10 hole of JMTR fuel zone for 2 reactor cycles, and 72F-7A capsule had been planned to be irradiated at the same irradiation hole before 72F-6A. However, due to slight leak of the gaseous fission products into the vacuum system controlling irradiation temperature, irradiation of 72F-7A capsule was ceased after 85 hrs since the beginning. In the post irradiation examination, inspection to surface appearance, ceramography, X-ray microradiography and acid leaching for the irradiated particle samples were made, and crushing strength of the two particle samples was measured. (author)

The failure mechanisms of HTR coated particle fuel and computer code

International Nuclear Information System (INIS)

Yang Lin; Liu Bing; Shao Youlin; Liang Tongxiang; Tang Chunhe

2010-01-01

The basic constituent unit of fuel element in HTR is ceramic coated particle fuel. And the performance of coated particle fuel determines the safety of HTR. In addition to the traditional detection of radiation experiments, establishing computer code is of great significance to the research. This paper mainly introduces the structure and the failure mechanism of TRISO-coated particle fuel, as well as a few basic assumptions,principles and characteristics of some existed main overseas codes. Meanwhile, this paper has proposed direction of future research by comparing the advantages and disadvantages of several computer codes. (authors)

Fluidized combustion of beds of large, dense particles in reprocessing HTGR fuel

International Nuclear Information System (INIS)

Young, D.T.

1977-03-01

Fluidized bed combustion of graphite fuel elements and carbon external to fuel particles is required in reprocessing high-temperature gas-cooled reactor (HTGR) cores for recovery of uranium. This burning process requires combustion of beds containing both large particles and very dense particles as well as combustion of fine graphite particles which elutriate from the bed. Equipment must be designed for optimum simplicity and reliability as ultimate operation will occur in a limited access ''hot cell'' environment. Results reported in this paper indicate that successful long-term operation of fuel element burning with complete combustion of all graphite fines leading to a fuel particle product containing <1% external carbon can be performed on equipment developed in this program

Pyrometric fuel particle measurements in pressurised reactors

Energy Technology Data Exchange (ETDEWEB)

Hernberg, R.; Joutsenoja, T. [Tampere Univ. of Technology (Finland)

1996-12-01

A fiberoptic two-colour pyrometric technique for fuel particle temperature and size measurement is modified and applied to three pressurized reactors of different type in Finland, Germany and France. A modification of the pyrometric method for simultaneous in situ measurement of the temperature and size of individual pulverized coal particles at the pressurized entrained flow reactor in Jyvaeskylae was developed and several series of measurements were made. In Orleans a fiberoptic pyrometric device was installed to a pressurised thermogravimetric reactor and the two-colour temperatures of fuel samples were measured. Some results of these measurements are presented. The project belongs to EU`s Joule 2 extension research programme. (author)

Automatic particle-size analysis of HTGR recycle fuel

International Nuclear Information System (INIS)

Mack, J.E.; Pechin, W.H.

1977-09-01

An automatic particle-size analyzer was designed, fabricated, tested, and put into operation measuring and counting HTGR recycle fuel particles. The particle-size analyzer can be used for particles in all stages of fabrication, from the loaded, uncarbonized weak acid resin up to fully-coated Biso or Triso particles. The device handles microspheres in the range of 300 to 1000 μm at rates up to 2000 per minute, measuring the diameter of each particle to determine the size distribution of the sample, and simultaneously determining the total number of particles. 10 figures

Improvements in the preparation of nuclear fuel elements with addition of a molding mixture to fuel particles

International Nuclear Information System (INIS)

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

1975-01-01

An improved molting mixture to be added to nuclear fuel particles for the preparation of nuclear fuel elements is presented. It consists of carbon and pitch particles and contains an additive reducing the final coke yield of the fuel mass formed. This additive is chosen from: polystyrene and copolymers of styrene and butadiene of molecular weight between 500 and 1000000; aromatic compounds of molecular weight between 75 and 300; saturated hydrocarbon polymers of molecular weight between 500 and 1000000. The additive may be camphor, naphthalene, anthracene, phenanthrene, dimethyl terephthalate or their mixtures and is present at a concentration of 5 to 50% by weight. The carbon particles used consist of powdered graphite. These fuel elements are intended for gas-cooled high-temperature reactors [fr

Development of a pneumatic transfer system for HTGR recycle fuel particles

International Nuclear Information System (INIS)

Mack, J.E.; Johnson, D.R.

1978-02-01

In support of the High-Temperature Gas-Cooled Reactor (HTGR) Fuel Refabrication Development Program, an experimental pneumatic transfer system was constructed to determine the feasibility of pneumatically conveying pyrocarbon-coated fuel particles of Triso and Biso designs. Tests were conducted with these particles in each of their nonpyrophoric forms to determine pressure drops, particle velocities, and gas flow requirements during pneumatic transfer as well as to evaluate particle wear and breakage. Results indicated that the material can be pneumatically conveyed at low pressures without excessive damage to the particles or their coatings

Development of a fissile particle for HTGR fuel recycle

International Nuclear Information System (INIS)

Homan, F.J.; Long, E.L. Jr.; Lindemer, T.B.; Beatty, R.L.; Tiegs, T.N.

1976-12-01

Recycle fissile fuel particles for high-temperature gas-cooled reactors (HTGRs) have been under development since the mid-1960s. Irradiation performance on early UO 2 and Th 0 . 8 U 0 . 2 O 2 kernels is described in this report, and the performance limitations associated with the dense oxide kernels are presented. The development of the new reference fuel kernel, the weak-acid-resin-derived (WAR) UO 2 --UC 2 , is discussed in detail, including an extensive section on the irradiation performance of this fuel in HFIR removable beryllium capsules HRB-7 through -10. The conclusion is reached that the irradiation performance of the WAR fissile fuel kernel is better than that of any coated particle fuel yet tested. Further, the present fissile kernel is adequate for steam cycle HTGRs as well as for many advanced applications such as gas turbine and process heat HTGRs

Small PWR 'PFPWR50' using cermet fuel of Th-Pu particles

International Nuclear Information System (INIS)

Hirayama, Takashi; Shimazu, Yoichiro

2009-01-01

An innovative concept of PFPWR50 has been studied. The main feature of PFPWR50 has been to adopt TRISO coated fuel particles in a conventional PWR cladding. Coated fuel particle provides good confining ability of fission products. But it is pointed out that swelling of SiC layer at low temperature by irradiation has possibilities of degrading the integrity of coated fuel particle in the LWR environment. Thus, we examined the use of Cermet fuel replacing SiC layer to Zr metal or Zr compound. And the nuclear fuel has been used as fuel compact, which is configured to fix coated fuel particles in the matrix material to the shape of fuel pellet. In the previous study, graphite matrix is adopted as the matrix material. According to the burnup calculations of the several fuel concepts with those covering layers, we decide to use Zr layer embedded in Zr metal base or ZrC layer with graphite matrix. But carbon has the problem at low temperature by irradiation as well as SiC. Therefore, Zr covering layer and Zr metal base are finally selected. The other feature of PFPWR50 concept has been that the excess reactivity is suppressed during a cycle by initially loading burnable poison (gadolinia) in the fuels. In this study, a new loading pattern is determined by combining 7 types of assemblies in which the gadolinia concentration and the number of the fuel rods with gadolinia are different. This new core gives 6.7 equivalent full power years (EFPY) as the core life of a cycle. And the excess reactivity is suppressed to less than 2.0%Δk/k during the cycle. (author)

Experiments in MARIUS on HTR tubular fuel with loose particles

Energy Technology Data Exchange (ETDEWEB)

Bosser, R; Langlet, G

1972-06-15

The work described on HTR tubular fuel with loose particles is the first part of a program in three points. The cell is the same in the three experiments, only particles in the fuel container are changed. The aim of the experiment is to achieve the buckling in a critical facility. A description of the techniques of measurements, calculations, and results are presented.

Key differences in the fabrication of US and German TRISO-coated particle fuel, and their implications on fuel performance

International Nuclear Information System (INIS)

Petti, D.A.; Buongiorno, J.; Maki, J.T.; Miller, G.K.; Hobbins, R.R.

2002-01-01

Historically, the irradiation performance of TRISO-coated gas reactor particle fuel in Germany has been superior to that in the US. German fuel generally displayed in-pile gas release values that were three orders of magnitude lower than US fuel. Thus, we have critically examined the TRISO-coated fuel fabrication processes in the US and German and the associated irradiation database with a goal of understanding why the German fuel behaves acceptably, why the US fuel has not faired as well, and what process/production parameters impart the reliable performance to this fuel form. The postirradiation examination results are also reviewed to identify failure mechanisms that may be the cause of the poorer US irradiation performance. This comparison will help determine the roles that particle fuel process/product attributes and irradiation conditions (burnup, fast neutron fluence, temperature, degree of acceleration, power per particle) have on the behavior of the fuel during irradiation and provide a more quantitative linkage between acceptable processing parameters, as-fabricated fuel properties and subsequent in-reactor performance. (author)

Review of experimental studies of zirconium carbide coated fuel particles for high temperature gas-cooled reactors

International Nuclear Information System (INIS)

Minato, Kazuo; Ogawa, Toru; Fukuda, Kousaku

1995-03-01

Experimental studies of zirconium carbide(ZrC) coated fuel particles were reviewed from the viewpoints of fuel particle designs, fabrication, characterization, fuel performance, and fission product retentiveness. ZrC is known as a refractory and chemically stable compound, so ZrC is a candidate to replace the silicon carbide(SiC) coating layer of the Triso-coated fuel particles. The irradiation experiments, the postirradiation heating tests, and the out-of-reactor experiments showed that the ZrC layer was less susceptible than the SiC layer to chemical attack by fission products and fuel kernels, and that the ZrC-coated fuel particles performed better than the standard Triso-coated fuel particles at high temperatures, especially above 1600degC. The ZrC-coated fuel particles demonstrated better cesium retention than the standard Triso-coated fuel particles though the ZrC layer showed a less effective barrier to ruthenium than the SiC layer. (author) 51 refs

Washing of gel particles in wet chemical manufacture of reactor fuel particles

International Nuclear Information System (INIS)

Ringel, H.

1980-07-01

In the manufacture of HTR fuel particles and particles of fertile material by wet chemical methods, the ammonium nitrate formed during the precipitation reaction must be washed out of the gel particles. This washing process has been investigated theoretically and experimentally. A counter-current washer has been developed which in particular takes account of the aspects of refabrication - such as compact construction and minimum waste. A counter-current washing column of 17 mm internal diameter and 640 mm length gives to gel particle throughput of 0.65 1/h. The volume ratio of wash water to gel particles is 5, and the residual nitrate concentration in the particles is 7 x 10 -3 mols of NO - 3 /1. (orig.) [de

Research on in-pile release of fission products from coated particle fuels

International Nuclear Information System (INIS)

Fukuda, K.; Iwamoto, K.

1985-01-01

Coated particle fuels fabricated in accordance with VHTR (Very High Temperature gas-cooled Reactor) fuel design have been irradiated by both capsules and an in-pile gas loop (OGL-1), and data on the fission products release under irradiation were obtained for loose coated particles, fuel compacts and fuel rods in the temperature range between 800 deg. C and 1600 deg. C. For the fission gases, temperature- and time dependences of the fractional release(R/B) were measured. Relation between release and failure fraction of the coated particles was elucidated on the VHTR reference fuels. Also measured was tritium concentration in the helium coolant of OGL-1. In-pile release behavior of the metallic fission products was studied by measuring the activities of the fission products adsorbed in the graphite sleeves of the OGL-1 fuel rods and the graphite fuel container of the sweep gas capsules in the PIE. Investigation on palladium interaction with SiC coating layer was included. (author)

SPOUTED BED DESIGN CONSIDERATIONS FOR COATED NUCLEAR FUEL PARTICLES

Energy Technology Data Exchange (ETDEWEB)

Marshall, Douglas W.

2017-07-01

High Temperature Gas Cooled Reactors (HTGRs) are fueled with tristructural isotropic (TRISO) coated nuclear fuel particles embedded in a carbon-graphite fuel body. TRISO coatings consist of four layers of pyrolytic carbon and silicon carbide that are deposited on uranium ceramic fuel kernels (350µm – 500µm diameters) in a concatenated series of batch depositions. Each layer has dedicated functions such that the finished fuel particle has its own integral containment to minimize and control the release of fission products into the fuel body and reactor core. The TRISO coatings are the primary containment structure in the HTGR reactor and must have very high uniformity and integrity. To ensure high quality TRISO coatings, the four layers are deposited by chemical vapor deposition (CVD) using high purity precursors and are applied in a concatenated succession of batch operations before the finished product is unloaded from the coating furnace. These depositions take place at temperatures ranging from 1230°C to 1550°C and use three different gas compositions, while the fuel particle diameters double, their density drops from 11.1 g/cm3 to 3.0 g/cm3, and the bed volume increases more than 8-fold. All this is accomplished without the aid of sight ports or internal instrumentation that could cause chemical contamination within the layers or mechanical damage to thin layers in the early stages of each layer deposition. The converging section of the furnace retort was specifically designed to prevent bed stagnation that would lead to unacceptably high defect fractions and facilitate bed circulation to avoid large variability in coating layer dimensions and properties. The gas injection nozzle was designed to protect precursor gases from becoming overheated prior to injection, to induce bed spouting and preclude bed stagnation in the bottom of the retort. Furthermore, the retort and injection nozzle designs minimize buildup of pyrocarbon and silicon carbide on the

Novel technique for manipulating MOX fuel particles using radiation pressure of a laser light

International Nuclear Information System (INIS)

Omori, R.

2000-01-01

We have continued theoretical and experimental studies on laser manipulation of nuclear fuel particles, such as UO 2 , PuO 2 and ThO 2 , In this paper, we investigate the applicability of the collection of MOX particles floating in air using radiation pressure of a laser light; some preliminary results are shown. This technique will be useful for removal and confinement of MOX particles being transported by air current or dispersed in a cell box. First, we propose two types of principles for collecting MOX particles. Second, we show some experimental results, Third, we show numerical results of radiation pressure exerted on submicrometer-sized UO 2 particles using Generalized Lorentz-Mie theory. Because optical constants of UO 2 are similar to those of MOX fuel particles, it seems that calculation results obtained hold for MOX fuel particles. 2. Principles of collecting MOX fuel particles using radiation pressure (authors)

Crushing strength of HTGR fuel particles

International Nuclear Information System (INIS)

Lackey, W.J.; Stinton, D.P.; Davis, L.E.; Beatty, R.L.

1976-01-01

The whole-particle crushing strengths of High-Temperature Gas-Cooled Reactor fertile and fissile coated particles were measured and correlated with fabrication procedures. The crushing strength of Biso-coated fertile particles was increased by the following factors: (1) increasing the outer coating thickness by 10 μm increased strengths by 0.3 lb (1.3 N) for annealed particles and by 0.5 lb (2.2 N) for unannealed particles. (2) An 1800 0 C postcoating anneal increased strengths by 1 lb (4.4 N) for particles with thick outer coatings and by 2 lb (8.9 N) for particles having thin coatings. (3) Increasing the inner coating density by 0.1 g/cm 3 increased strength by 0.6 lb (2.7 N). The crushing strength of Triso-coated fissile particles was proportional to the thickness of the SiC coatings, and strength decreased on annealing by about 0.2 lb (0.9 N) when a porous plate was used to distribute the coating gas and by about 1.5 lb (6.7 N) when a conical gas distributor was used. The strengths of fertile and fissile coated particles as well as uncoated kernels appear adequate to allow fuel fabrication without excessive particle damage

Thermochemical equilibrium in a kernel of a UN TRISO coated fuel particle

International Nuclear Information System (INIS)

Kim, Young Min; Jo, C. K.; Lim, H. S.; Cho, M. S.; Lee, W. J.

2012-01-01

A coated fuel particle (CFP) with a uranium mononitride (UN) kernel has been recently considered as an advanced fuel option, such as in fully ceramic micro encapsulated (FCM) replacement fuel for light water reactors (LWRs). In FCM fuel, a large number of tri isotropic coated fuel particles (TRISOs) are embedded in a silicon carbide (SiC) matrix. Thermochemical equilibrium calculations can predict the chemical behaviors of a kernel in a TRISO of FCM fuel during irradiation. They give information on the kind and quantity of gases generated in a kernel during irradiation. This study treats the quantitative analysis of thermochemical equilibrium in a UN TRISO of FCM LWR fuel using HSC software

Characteristics of SME biodiesel-fueled diesel particle emissions and the kinetics of oxidation.

Science.gov (United States)

Jung, Heejung; Kittelson, David B; Zachariah, Michael R

2006-08-15

Biodiesel is one of the most promising alternative diesel fuels. As diesel emission regulations have become more stringent, the diesel particulate filter (DPF) has become an essential part of the aftertreatment system. Knowledge of kinetics of exhaust particle oxidation for alternative diesel fuels is useful in estimating the change in regeneration behavior of a DPF with such fuels. This study examines the characteristics of diesel particulate emissions as well as kinetics of particle oxidation using a 1996 John Deere T04045TF250 off-highway engine and 100% soy methyl ester (SME) biodiesel (B100) as fuel. Compared to standard D2 fuel, this B100 reduced particle size, number, and volume in the accumulation mode where most of the particle mass is found. At 75% load, number decreased by 38%, DGN decreased from 80 to 62 nm, and volume decreased by 82%. Part of this decrease is likely associated with the fact that the particles were more easily oxidized. Arrhenius parameters for the biodiesel fuel showed a 2-3times greater frequency factor and approximately 6 times higher oxidation rate compared to regular diesel fuel in the range of 700-825 degrees C. The faster oxidation kinetics should facilitate regeneration when used with a DPF.

Fueling profile sensitivities of trapped particle mode transport to TNS

International Nuclear Information System (INIS)

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

1977-01-01

A key factor in the plasma thermal behavior is the anticipated existence of dissipative trapped particle modes. A possible scheme for controlling the strength of these modes was found. The scheme involves varying the cold fueling profile. A one dimensional multifluid transport code was used to simulate plasma behavior. A multiregime model for particle and energy transport was incorporated based on pseudoclassical, trapped electron, and trapped ion regimes used elsewhere in simulation of large tokamaks. Fueling profiles peaked toward the plasma edge may provide a means for reducing density-gradient-driven trapped particle modes, thus reducing diffusion and conduction losses

Evaluation of Particle Counter Technology for Detection of Fuel Contamination Detection Utilizing Fuel System Supply Point

Science.gov (United States)

2014-06-19

product used as a diesel product for ground use (1). Free water contamination (droplets) may appear as fine droplets or slugs of water in the fuel...methods and test procedures for the calibration and use of automatic particle counters. The transition of this technology to the fuel industry is...UNCLASSIFIED 6 UNCLASSIFIED Receipt Vehicle Fuel Tank Fuel Injector Aviation Fuel DEF (AUST) 5695B 18/16/13 Parker 18

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)

Calculating failure probabilities for TRISO-coated fuel particles using an integral formulation

International Nuclear Information System (INIS)

Miller, Gregory K.; Maki, John T.; Knudson, Darrell L.; Petti, David A.

2010-01-01

The fundamental design for a gas-cooled reactor relies on the safe behavior of the coated particle fuel. The coating layers surrounding the fuel kernels in these spherical particles, termed the TRISO coating, act as a pressure vessel that retains fission products. The quality of the fuel is reflected in the number of particle failures that occur during reactor operation, where failed particles become a source for fission products that can then diffuse through the fuel element. The failure probability for any batch of particles, which has traditionally been calculated using the Monte Carlo method, depends on statistical variations in design parameters and on variations in the strengths of coating layers among particles in the batch. An alternative approach to calculating failure probabilities is developed herein that uses direct numerical integration of a failure probability integral. Because this is a multiple integral where the statistically varying parameters become integration variables, a fast numerical integration approach is also developed. In sample cases analyzed involving multiple failure mechanisms, results from the integration methods agree closely with Monte Carlo results. Additionally, the fast integration approach, particularly, is shown to significantly improve efficiency of failure probability calculations. These integration methods have been implemented in the PARFUME fuel performance code along with the Monte Carlo method, where each serves to verify accuracy of the others.

Randomly dispersed particle fuel model in the PSG Monte Carlo neutron transport code

International Nuclear Information System (INIS)

Leppaenen, J.

2007-01-01

High-temperature gas-cooled reactor fuels are composed of thousands of microscopic fuel particles, randomly dispersed in a graphite matrix. The modelling of such geometry is complicated, especially using continuous-energy Monte Carlo codes, which are unable to apply any deterministic corrections in the calculation. This paper presents the geometry routine developed for modelling randomly dispersed particle fuels using the PSG Monte Carlo reactor physics code. The model is based on the delta-tracking method, and it takes into account the spatial self-shielding effects and the random dispersion of the fuel particles. The calculation routine is validated by comparing the results to reference MCNP4C calculations using uranium and plutonium based fuels. (authors)

Fuel particles in the Chernobyl cooling pond: current state and prediction for remediation options

International Nuclear Information System (INIS)

Bulgakov, A.; Konoplev, A.; Smith, J.; Laptev, G.; Voitsekhovich, O.

2009-01-01

During the coming years, a management and remediation strategy for the Chernobyl cooling pond (CP) will be implemented. Remediation options include a controlled reduction in surface water level of the cooling pond and stabilisation of exposed sediments. In terrestrial soils, fuel particles deposited during the Chernobyl accident have now almost completely disintegrated. However, in the CP sediments the majority of 90 Sr activity is still in the form of fuel particles. Due to the low dissolved oxygen concentration and high pH, dissolution of fuel particles in the CP sediments is significantly slower than in soils. After the planned cessation of water pumping from the Pripyat River to the Pond, significant areas of sediments will be drained and exposed to the air. This will significantly enhance the dissolution rate and, correspondingly, the mobility and bioavailability of radionuclides will increase with time. The rate of acidification of exposed bottom sediments was predicted on the basis of acidification of similar soils after liming. Using empirical equations relating the fuel particle dissolution rate to soil and sediment pH allowed prediction of fuel particle dissolution and 90 Sr mobilisation for different remediation scenarios. It is shown that in exposed sediments, fuel particles will be almost completely dissolved in 15-25 years, while in parts of the cooling pond which remain flooded, fuel particle dissolution will take about a century

A novel concept of QUADRISO particles Part III: applications to the plutonium-thorium fuel cycle

International Nuclear Information System (INIS)

Talamo, A.

2009-01-01

In the present study, a plutonium-thorium fuel cycle is investigated including the 233 U production and utilization. A prismatic thermal High Temperature Gas Reactor (HTGR) and the novel concept of quadruple isotropic (QUADRISO) coated particles, designed at the Argonne National Laboratory, have been used for the study. In absorbing QUADRISO particles, a burnable poison layer surrounds the central fuel kernel to flatten the reactivity curve as a function of time. At the beginning of life, the fuel in the QUADRISO particles is hidden from neutrons, since they get absorbed in the burnable poison before they reach the fuel kernel. Only when the burnable poison depletes, neutrons start streaming into the fuel kernel inducing fission reactions and compensating the fuel depletion of ordinary TRISO particles. In fertile QUADRISO particles, the absorber layer is replaced by natural thorium with the purpose of flattening the excess of reactivity by the thorium resonances and producing 233 U. The above configuration has been compared with a configuration where fissile (neptunium-plutonium oxide from Light Water Reactors irradiated fuel) and fertile (natural thorium oxide) fuels are homogeneously mixed in the kernel of ordinary TRISO particles. For the 233 U utilization, the core has been equipped with europium oxide absorbing QUADRISO particles.

Nuclear fuel particles in the environment - characteristics, atmospheric transport and skin doses

International Nuclear Information System (INIS)

Poellaenen, R.

2002-05-01

In the present thesis, nuclear fuel particles are studied from the perspective of their characteristics, atmospheric transport and possible skin doses. These particles, often referred to as 'hot' particles, can be released into the environment, as has happened in past years, through human activities, incidents and accidents, such as the Chernobyl nuclear power plant accident in 1986. Nuclear fuel particles with a diameter of tens of micrometers, referred to here as large particles, may be hundreds of kilobecquerels in activity and even an individual particle may present a quantifiable health hazard. The detection of individual nuclear fuel particles in the environment, their isolation for subsequent analysis and their characterisation are complicated and require well-designed sampling and tailored analytical methods. In the present study, the need to develop particle analysis methods is highlighted. It is shown that complementary analytical techniques are necessary for proper characterisation of the particles. Methods routinely used for homogeneous samples may produce erroneous results if they are carelessly applied to radioactive particles. Large nuclear fuel particles are transported differently in the atmosphere compared with small particles or gaseous species. Thus, the trajectories of gaseous species are not necessarily appropriate for calculating the areas that may receive large particle fallout. A simplified model and a more advanced model based on the data on real weather conditions were applied in the case of the Chernobyl accident to calculate the transport of the particles of different sizes. The models were appropriate in characterising general transport properties but were not able to properly predict the transport of the particles with an aerodynamic diameter of tens of micrometers, detected at distances of hundreds of kilometres from the source, using only the current knowledge of the source term. Either the effective release height has been higher

Chemical thermodynamics of iodine species in the HTGR fuel particle

International Nuclear Information System (INIS)

Lindemer, T.B.

1982-09-01

The iodine-containing species in an intact fuel particle in the high-temperature gas-cooled reactor (HTGR) have been calculated. Assumptions include: (1) attainment of chemical thermodynamic equilibrium among all species in the open porosity of the particle, primarily in the buffer layer; and (2) fission-product concentrations in proportion to their yields. The primary gaseous species is calculated to be cesium iodide; in carbide-containing fuels, gaseous barium iodide may exhibit equivalent pressures. The condensed iodine-containing phase is usually cesium iodide, but in carbide-containing fuels, barium iodide may be stable instead. Absorption of elemental iodine on the carbon in the particle appears to be less than or equal to 10 -4 μg I/g C. The fission-product-spectra excess of cesium over iodine would generally be adsorbed on the carbon, but may form Cs 2 MoO 4 under some circumstances

Corrosion Studies of Platinum Nano-Particles for Fuel Cells

DEFF Research Database (Denmark)

Shim, Signe Sarah

The main focus of the present thesis is on corrosion and prevention of corrosion of platinum particles supported on carbon. This is important for instance in connection with start up and shutdown of fuel cells. The degradation mechanism of platinum particles supported on carbon has been character......The main focus of the present thesis is on corrosion and prevention of corrosion of platinum particles supported on carbon. This is important for instance in connection with start up and shutdown of fuel cells. The degradation mechanism of platinum particles supported on carbon has been...... characterized during oxygen reduction reaction (ORR) condition using identical location (IL) transmission electron microscopy (TEM). A TEM grid was used as the working electrode in an electrochemical setup allowing a direct correlation between the electrochemical response and the TEM analysis. The main results...... thirds and one monolayer of gold on platinum supported on carbon were synthesized by an inverse micelle method. The results obtained appear independent of the gold coverage. It has been shown that the electrochemical active surface areas of the platinum and platinum gold particles synthesized...

HTGR fuel particle crusher design evaluation

International Nuclear Information System (INIS)

Johanson, N.W.

1978-10-01

This report describes an evaluation of the design of the existing engineering-scale fuel particle crushing system for the HTGR reprocessing cold pilot plant at General Atomic Company (GA). The purpose of this evaluation is to assess the suitability of the existing design as a prototype of the HTGR Recycle Reference Facility (HRRF) particle crushing system and to recommend alternatives where the existing design is thought to be unsuitable as a prototype. This evaluation has led to recommendations for an upgraded design incorporating improvements in bearing and seal arrangement, housing construction, and control of roll gap thermal expansion. 23 figures, 6 tables

Design and development on automated control system of coated fuel particle fabrication process

International Nuclear Information System (INIS)

Liu Malin; Shao Youlin; Liu Bing

2013-01-01

With the development trend of the large-scale production of the HTR coated fuel particles, the original manual control system can not meet the requirement and the automation control system of coated fuel particle fabrication in modern industrial grade is needed to develop. The comprehensive analysis aiming at successive 4-layer coating process of TRISO type coated fuel particles was carried out. It was found that the coating process could be divided into five subsystems and nine operating states. The establishment of DCS-type (distributed control system) of automation control system was proposed. According to the rigorous requirements of preparation process for coated particles, the design considerations of DCS were proposed, including the principle of coordinated control, safety and reliability, integration specification, practical and easy to use, and open and easy to update. A complete set of automation control system for coated fuel particle preparation process was manufactured based on fulfilling the requirements of these principles in manufacture practice. The automated control system was put into operation in the production of irradiated samples for HTRPM demonstration project. The experimental results prove that the system can achieve better control of coated fuel particle preparation process and meet the requirements of factory-scale production. (authors)

Pseudo three-dimensional modeling of particle-fuel packing using distinct element method

International Nuclear Information System (INIS)

Yuki, Daisuke; Takata, Takashi; Yamaguchi, Akira

2007-01-01

Vibration-based packing of sphere-pac fuel is a key technology in a nuclear fuel manufacturing. In the production process of sphere-pac fuel, a Mixed Oxide (MOX) fuel is formed to spherical form and is packed in a cladding tube by adding a vibration force. In the present study, we have developed a numerical simulation method to investigate the behavior of the particles in a vibrated tube using the Distinct Element Method (DEM). In general, the DEM requires a significant computational cost. Therefore we propose a new approach in which a small particle can move through the space between three larger particles even in the two-dimensional simulation. We take into account an equivalent three-dimensional effect in the equations of motion. Thus it is named pseudo three-dimensional modeling. (author)

Method to produce carbon-cladded nuclear fuel particles

International Nuclear Information System (INIS)

Sturge, D.W.; Meaden, G.W.

1978-01-01

In the method charges of micro-spherules of fuel element are designed to have two carbon layers, whereby a one aims to achieve a uniform granulation (standard measurement). Two drums are used for this purpose connected behind one another. The micro-spherules coated with the first layer (phenolformaldehyde resin coated graphite particles) leave the first drum and enter the second one. Following the coating with a second layer, the micro-spherules are introduced into a grain size separator. The spherules that are too small are directly recycled into the second drum and those ones that are too large are recycled into the first drum after removing the graphite layers. The method may also be applied to metal cladded particles to manufacture cermet fuels. (RW) [de

Fluoride-Salt-Cooled High-Temperature Reactor (FHR) with Silicon-Carbide-Matrix Coated-Particle Fuel

International Nuclear Information System (INIS)

Forsberg, C. W.; Snead, Lance Lewis; Katoh, Yutai

2012-01-01

The FHR is a new reactor concept that uses coated-particle fuel and a low-pressure liquid-salt coolant. Its neutronics are similar to a high-temperature gas-cooled reactor (HTGR). The power density is 5 to 10 times higher because of the superior cooling properties of liquids versus gases. The leading candidate coolant salt is a mixture of 7 LiF and BeF 2 (FLiBe) possessing a boiling point above 1300 C and the figure of merit ρC p (volumetric heat capacity) for the salt slightly superior to water. Studies are underway to define a near-term base-line concept while understanding longer-term options. Near-term options use graphite-matrix coated-particle fuel where the graphite is both a structural component and the primary neutron moderator. It is the same basic fuel used in HTGRs. The fuel can take several geometric forms with a pebble bed being the leading contender. Recent work on silicon-carbide-matrix (SiCm) coated-particle fuel may create a second longer-term fuel option. SiCm coated-particle fuels are currently being investigated for use in light-water reactors. The replacement of the graphite matrix with a SiCm creates a new family of fuels. The first motivation behind the effort is to take advantage of the superior radiation resistance of SiC compared to graphite in order to provide a stable matrix for hosting coated fuel particles. The second motivation is a much more rugged fuel under accident, repository, and other conditions.

Fuel Design for Particle-Bed Reactors for Thermal Propulsion Applications

Science.gov (United States)

Husser, Dewayne L.; Evans, Robert S.; Jensen, Russell R.; Kerr, John M.

1994-07-01

The design of particle bed reactor (PBR) fuels is an iterative process involving close coordination of design and manufacturing operations. The process starts with the generation of an initial particle design, based on a knowledge of the system requirements and interfaces (such as, fissile loading requirements, coolant type, exit gas temperatures, operation time, number of cycles, contacting materials, etc.). The designer must consider materials property data, heat-transfer and thermal-hydraulic characteristics of the particle and particle bed, and available (or anticipated) manufacturing technology. The design process also uses parametric studies to identify the influences of composition, size, and coating thickness on fuel performance. This resulting design is then used to provide a target manufacturing specification against which initial manufacturing development can be assessed and which provides the framework for manufacturing and testing derived feedback that can be incorporated into the subsequent particle design modifications. In this paper, an example of this design process for a hypothetical particle using a (U,Zr)C kernel and a NbC outer coating designed for a thermal propulsion application is given.

Automatic size analysis of coated fuel particles

International Nuclear Information System (INIS)

Wallisch, K.; Koss, P.

1977-01-01

The determination of the diameter, coating thickness, and sphericity of coated fuel particles by conventional methods is very time consuming. Therefore, statistical data can only be obtained with limited accuracy. An alternative method is described that avoids these disadvantages by utilizing a fast optical data-collecting system of high accuracy. This system allows the determination of the diameter of particles in the range between 100 and 1500 μm, with an accuracy of better than +-2 μm and with a rate of 100 particles per second. The density and thickness of coating layers can be determined by comparing the data obtained before and after coating, taking into account the relative increase of weight. A special device allows the automatic determination of the sphericity of single particles as well as the distribution in a batch. This device measures 50 to 100 different diameters of each particle per second. An on-line computer stores the measured data and calculates all parameters required, e.g., number of particles measured, particle diameter, standard deviation, diameter limiting values, average particle volume, average particle surface area, and the distribution of sphericity in absolute and percent form

Application of boron and gadolinium burnable poison particles in UO2 and PUO2 fuels in HTRs

International Nuclear Information System (INIS)

Kloosterman, J.L.

2003-01-01

Burnup calculations have been performed on a standard HTR fuel pebble (fuel zone with radius of 2.5 cm surrounded with a 0.5 cm thick graphite layer) and burnable poison particles (BPPs) containing B 4 C made of pure 10 B or containing Gd 2 O 3 made of natural Gd. Two types of fuel were considered: UO 2 fuel made of 8% enriched uranium and PuO 2 fuel made of plutonium from LWR spent fuel. The radius of the BPP and the number of particles per fuel pebble were varied to find the flattest reactivity-to-time curve. For the UO 2 fuel, the reactivity swing is lowest (around 2%) for BPPs made of B 4 C with radius of 75 μm. In this case around 1070 BPPs per fuel pebble are needed. For the PuO 2 fuel to get a reactivity swing below 4%, the optimal radius of the BPP is the same, but the number of particles per fuel pebble should be around 1600. The optimal radius of the Gd 2 O 3 particles in the UO 2 fuel is about 10 times that of the B 4 C particles. The reactivity swing is around 3% when each fuel pebble contains only 9 BPPs with radius of 840 μm. The results of the Gd particles illustrate nicely the usage of black burnable poison particles introduced by Van Dam [Ann. Nuclear Energy 27 (2000) 733

Nuclear fuel particles in the environment - characteristics, atmospheric transport and skin doses

Energy Technology Data Exchange (ETDEWEB)

Poellaenen, R

2002-05-01

In the present thesis, nuclear fuel particles are studied from the perspective of their characteristics, atmospheric transport and possible skin doses. These particles, often referred to as 'hot' particles, can be released into the environment, as has happened in past years, through human activities, incidents and accidents, such as the Chernobyl nuclear power plant accident in 1986. Nuclear fuel particles with a diameter of tens of micrometers, referred to here as large particles, may be hundreds of kilobecquerels in activity and even an individual particle may present a quantifiable health hazard. The detection of individual nuclear fuel particles in the environment, their isolation for subsequent analysis and their characterisation are complicated and require well-designed sampling and tailored analytical methods. In the present study, the need to develop particle analysis methods is highlighted. It is shown that complementary analytical techniques are necessary for proper characterisation of the particles. Methods routinely used for homogeneous samples may produce erroneous results if they are carelessly applied to radioactive particles. Large nuclear fuel particles are transported differently in the atmosphere compared with small particles or gaseous species. Thus, the trajectories of gaseous species are not necessarily appropriate for calculating the areas that may receive large particle fallout. A simplified model and a more advanced model based on the data on real weather conditions were applied in the case of the Chernobyl accident to calculate the transport of the particles of different sizes. The models were appropriate in characterising general transport properties but were not able to properly predict the transport of the particles with an aerodynamic diameter of tens of micrometers, detected at distances of hundreds of kilometres from the source, using only the current knowledge of the source term. Either the effective release height has

Spot Ignition of Natural Fuels by Hot Metal Particles

OpenAIRE

Urban, James Linwood

2017-01-01

The spot ignition of combustible material by hot metal particles is an important pathway by which wildland and urban spot fires and smolders are started. Upon impact with a fuel, such as dry grass, duff, or saw dust, these particles can initiate spot fires by direct flaming or smoldering which can transition to a flame. These particles can be produced by processes such as welding, powerline interactions, fragments from bullet impacts, abrasive cutting, and pyrotechnics. There is little publi...

Quality control of coated fuel particles for high temperature gas-cooled reactor

International Nuclear Information System (INIS)

Kaneko, Mitsunobu

1987-01-01

The quality control of the coated fuel particles for high temperature gas-cooled reactors is characterized by the fact that the size of the target product to be controlled is very small, and the quantity is very large. Accordingly, the sampling plan and the method of evaluating the population through satisfically treating the measured data of the samples are the important subjects to see and evaluate the quality of a batch or a lot. This paper shows the fabrication process and the quality control procedure for the coated fuel particles. The development work of a HTGR was started by Japan Atomic Energy Research Institute in 1969, and as for the production technology for coated fuel particles, Nuclear Fuel Industries, Ltd. has continued the development work. The pilot plan with the capacity of about 40 kg/year was established in 1972. The fuel product fabricated in this plant was put to the irradiation experiment and out-of-pile evaluation test. In 1983, the production capacity was expanded to 200 kg/year, and the fuel compacts for the VHTRC in JAERI were produced for two years. The basic fuel design, the fabrication process, the quality control, the process control and the quality assurance are reported. For the commercial product, the studies from the viewpoint of production and quality control costs are required. (Kako, I.)

Novel technique for manipulating MOX fuel particles using radiation pressure of a laser light

International Nuclear Information System (INIS)

Omori, R.; Suzuki, A.

2001-01-01

We proposed two principles based on the laser manipulation technique for collecting MOX fuel particles floating in air. While Principle A was based on the acceleration of the MOX particles due to the radiation pressure of a visible laser light, Principle B was based on the gradient forces exerted on the particles when an infrared laser light was incident. Principle A was experimentally verified using MnO 2 particles. Numerical results also showed the possibility of collecting MOX fuel particles based on both the principles. (authors)

Pebble bed reactor fuel cycle optimization using particle swarm algorithm

Energy Technology Data Exchange (ETDEWEB)

Tavron, Barak, E-mail: btavron@bgu.ac.il [Planning, Development and Technology Division, Israel Electric Corporation Ltd., P.O. Box 10, Haifa 31000 (Israel); Shwageraus, Eugene, E-mail: es607@cam.ac.uk [Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

2016-10-15

Highlights: • Particle swarm method has been developed for fuel cycle optimization of PBR reactor. • Results show uranium utilization low sensitivity to fuel and core design parameters. • Multi-zone fuel loading pattern leads to a small improvement in uranium utilization. • Thorium mixes with highly enriched uranium yields the best uranium utilization. - Abstract: Pebble bed reactors (PBR) features, such as robust thermo-mechanical fuel design and on-line continuous fueling, facilitate wide range of fuel cycle alternatives. A range off fuel pebble types, containing different amounts of fertile or fissile fuel material, may be loaded into the reactor core. Several fuel loading zones may be used since radial mixing of the pebbles was shown to be limited. This radial separation suggests the possibility to implement the “seed-blanket” concept for the utilization of fertile fuels such as thorium, and for enhancing reactor fuel utilization. In this study, the particle-swarm meta-heuristic evolutionary optimization method (PSO) has been used to find optimal fuel cycle design which yields the highest natural uranium utilization. The PSO method is known for solving efficiently complex problems with non-linear objective function, continuous or discrete parameters and complex constrains. The VSOP system of codes has been used for PBR fuel utilization calculations and MATLAB script has been used to implement the PSO algorithm. Optimization of PBR natural uranium utilization (NUU) has been carried out for 3000 MWth High Temperature Reactor design (HTR) operating on the Once Trough Then Out (OTTO) fuel management scheme, and for 400 MWth Pebble Bed Modular Reactor (PBMR) operating on the multi-pass (MEDUL) fuel management scheme. Results showed only a modest improvement in the NUU (<5%) over reference designs. Investigation of thorium fuel cases showed that the use of HEU in combination with thorium results in the most favorable reactor performance in terms of

Pebble bed reactor fuel cycle optimization using particle swarm algorithm

International Nuclear Information System (INIS)

Tavron, Barak; Shwageraus, Eugene

2016-01-01

Highlights: • Particle swarm method has been developed for fuel cycle optimization of PBR reactor. • Results show uranium utilization low sensitivity to fuel and core design parameters. • Multi-zone fuel loading pattern leads to a small improvement in uranium utilization. • Thorium mixes with highly enriched uranium yields the best uranium utilization. - Abstract: Pebble bed reactors (PBR) features, such as robust thermo-mechanical fuel design and on-line continuous fueling, facilitate wide range of fuel cycle alternatives. A range off fuel pebble types, containing different amounts of fertile or fissile fuel material, may be loaded into the reactor core. Several fuel loading zones may be used since radial mixing of the pebbles was shown to be limited. This radial separation suggests the possibility to implement the “seed-blanket” concept for the utilization of fertile fuels such as thorium, and for enhancing reactor fuel utilization. In this study, the particle-swarm meta-heuristic evolutionary optimization method (PSO) has been used to find optimal fuel cycle design which yields the highest natural uranium utilization. The PSO method is known for solving efficiently complex problems with non-linear objective function, continuous or discrete parameters and complex constrains. The VSOP system of codes has been used for PBR fuel utilization calculations and MATLAB script has been used to implement the PSO algorithm. Optimization of PBR natural uranium utilization (NUU) has been carried out for 3000 MWth High Temperature Reactor design (HTR) operating on the Once Trough Then Out (OTTO) fuel management scheme, and for 400 MWth Pebble Bed Modular Reactor (PBMR) operating on the multi-pass (MEDUL) fuel management scheme. Results showed only a modest improvement in the NUU (<5%) over reference designs. Investigation of thorium fuel cases showed that the use of HEU in combination with thorium results in the most favorable reactor performance in terms of

Nuclear fuel element containing particles of an alloyed Zr, Ti, and Ni getter material

International Nuclear Information System (INIS)

Grossman, L.N.; Levin, H.A.

1975-01-01

A nuclear fuel element for use in the core of a nuclear reactor is disclosed. The nuclear fuel element has disposed therein an alloy having the essential components of nickel, titanium and zirconium, and the alloy reacts with water, water vapor and reactive gases at reactor ambient temperatures. The alloy is disposed in the plenum of the fuel element in the form of particles in a hollow gas permeable container having a multiplicity of openings of size smaller than the size of the particles. The openings permit gases and liquids entering the plenum to contact the particles of alloy. The container is preferably held in the spring in the plenum of the fuel element. (Official Gazette)

Operation Procedure of Inspection Equipment for TRISO-coated Fuel Particle

International Nuclear Information System (INIS)

Kim, S. H.; Kim, Y. K.; Cho, M. S.; Kim, Y. M.; Park, J. Y.; Kim, W. J.; Jeong, K. C.; Oh, S. C.; Lee, Y. W.

2007-03-01

TRISO-coated fuel particle for HTGR(high temperature gas cooled reactor) is composed of fuel kernel and coating layers. The kernel and coated particle are characterized by inspection processes for inspection items such as diameter of kernel, thickness, density and an-isotropy of coating layer. The coating thickness can be nondestructively measured by X-ray inspection equipment. The coating thickness as well as the sphericity can be also measured by optical inspection system as a ceramography method. The an-isotropy can be characterized by photometer. The density of coating layer can be measured by density column. The size and sphericity of particles can be measured by PSA(particle size analyzer). The thermo-chemical characteristics of kernel can be analyzed by TG/DTA(Thermogravimetric/Differential Thermal Analyzer). The inspection objective, equipment composition, operation principle, operation manual for each equipment was described in this operation procedure, which will be used for the characterization of inspection items described above

THE INFLUENCE OF CARBON BURNOUT ON SUBMICRON PARTICLE FORMATION FROM EMULSIFIED FUEL OIL COMBUSTION

Science.gov (United States)

The paper gives results of an examination of particle behavior and particle size distributions from the combustion of different fuel oils and emulsified fuels in three experimental combusators. Results indicate that improved carbon (C) burnout from fule oil combustion, either by...

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)

Thermomechanical behavior of fuel particles in a matrix during reactor power excursions

International Nuclear Information System (INIS)

Brittan, R.O.; Smith, R.S.

1977-01-01

This work determines the largest particle size that can be used in fabricating fuel material without exceeding temperature or stress criteria during transient operation. To do this temperature distribution histories must be determined for various particle sizes and volume fractions using typical power densities histories of transient reactor operation. From these, the critical stresses are calculated. The model chosen to accomplish this is a spherical fuel particle in a spherical matrix shell. Heat flow and temperature continuity conditions are imposed at the interface, and a zero temperature gradient is specified at the outer radius of the matrix shell. The particle power density is assumed to be uniform radially. Provisions are made for uniform power density in the matrix to model gamma heating and power density in interface layers to allow for radiant and fission fragment heating. A computer code was prepared to solve the model performance, yielding the temperature and stress distribution histories. Material property variation with temperature is employed, along with a close mockup of the power density history during self-limiting reactor transients. To date, four fuel systems have been investigated: 1) UC.ZrC particles in graphite; 2) UO 2 particles in graphite; 3) UO 2 particles in chromium 4) UO 2 particles in stainless steel. The study indicates that the maximum allowable particle diameter varies as the square root of the initial transient period and of the particle volume fraction. The critical thermophysical parameter is the thermal diffusivity of the particle, since in all cases studied it is many times smaller than that of the matrix. That of the UC.ZrC solid solution particle is 5 or more times larger than that of the UO 2 particle. It was found that the particles of system 1) above could be about 4 times larger than that of the other sy

Neutronics feasibility of using Gd2O3 particles in VVER-1000 fuel assembly

International Nuclear Information System (INIS)

Hoang Van Khanh; Hoang Thanh Phi Hung; Tran Hoai Nam

2016-01-01

Neutronics feasibility of using Gd 2 O 3 particles for controlling excess reactivity of VVER-1000 fuel assembly has been investigated. The motivation is that the use of Gd 2 O 3 particles would increase the thermal conductivity of the UO 2 +Gd 2 O 3 fuel pellet which is one of the desirable characteristics for designing future high burnup fuel. The calculation results show that the Gd 2 O 3 particles with the diameter of 60 µm could control the reactivity similarly to that of homogeneous mixture with the same amount of Gd 2 O 3 . The power densities at the fuel pin with Gd 2 O 3 particles increase by about 10-11%, leading to the decrease of the power peak and a slightly flatter power distribution. The power peak appears at the periphery pins at the beginning of burnup process which is decreased by 0.9 % when using Gd 2 O 3 particles. Further work and improvement are being planned to optimize the high power peaking at the beginning of burnup. (author)

Design and operation of equipment used to develop remote coating capability for HTGR fuel particles

International Nuclear Information System (INIS)

Suchomel, R.R.; Stinton, D.P.; Preston, M.K.; Heck, J.L.; Bolfing, B.J.; Lackey, W.J.

1978-12-01

Refabrication of HTGR fuels is a manufacturing process that consists of preparation of fuel kernels, application of multiple layers of pyrolytic carbon and silicon carbide, preparation of fuel rods, and assembly of fuel rods into fuel elements. All the equipment for refabrication of 233 U-containing fuel must be designed for completely remote operation and maintenance in hot-cell facilities. Equipment to remotely coated HTGR fuel particles has been designed and operated. Although not all of the equipment development needed for a fully remote coating system has been completed, significant progress has been made. The most important component of the coating furnace is the gas distributor, which must be simple, reliable, and easily maintainable. Techniques for loading and unloading the coater and handling microspheres have been developed. An engineering-scale system, currently in operation, is being used to verify the workability of these concepts. Coating crucible handling components are used to remove the crucible from the furnace, remove coated particles, and exchange the crucible, if necessary. After the batch of particles has been unloaded, it is transferred, weighed, and sampled. The components used in these processes have been tested to ensure that no particle breakage or holdup occurs. Tests of the particle handling system have been very encouraging because no major problems have been encountered. Instrumentation that controls the equipment performed very smoothly and reliably and can be operated remotely

Coated fuel particles: requirements and status of fabrication technology

International Nuclear Information System (INIS)

Huschka, H.; Vygen, P.

1977-01-01

Fuel cycle, design, and irradiation performance requirements impose restraints on the fabrication processes. Both kernel and coating fabrication processes are flexible enough to adapt to the needs of the various existing and proposed high-temperature gas-cooled reactors. Extensive experience has demonstrated that fuel kernels with excellent sphericity and uniformity can be produced by wet chemical processes. Similarly experience has shown that the various multilayer coatings can be produced to fully meet design and specification requirements. Quality reliability of coated fuel particles is ensured by quality control and quality assurance programs operated by an aduiting system that includes licensing officials and the customer

Physical and chemical analysis of interaction between oxide fuel and pyrocarbon coating of coated particles

International Nuclear Information System (INIS)

Lyutikov, R.A.; Kromov, Yu.F.; Chernikov, A.S.

1991-01-01

In terms of the model proposed the equilibrium pressure of gases (CO, Kr, Xe) in pyrocarbon-coated uranium dioxide fuel particles has been calculated, as function of the initial composition of the fuel (O/U), the design features of the coated particles, the fuel temperature, and the burnup. The possibility of reducing gas pressure in the particles by alloying the kernels with uranium carbide, and increasing the kernel capacity for retention of solid fission products by alloying the uranium oxide with aluminum-silicates, has been investigated. (author)

Gas Generation from K East Basin Sludges and Irradiated Metallic Uranium Fuel Particles Series III Testing

International Nuclear Information System (INIS)

Schmidt, Andrew J.; Delegard, Calvin H.; Bryan, Samuel A.; Elmore, Monte R.; Sell, Rachel L.; Silvers, Kurt L.; Gano, Susan R.; Thornton, Brenda M.

2003-01-01

The path forward for managing of Hanford K Basin sludge calls for it to be packaged, shipped, and stored at T Plant until final processing at a future date. An important consideration for the design and cost of retrieval, transportation, and storage systems is the potential for heat and gas generation through oxidation reactions between uranium metal and water. This report, the third in a series (Series III), describes work performed at the Pacific Northwest National Laboratory (PNNL) to assess corrosion and gas generation from irradiated metallic uranium particles (fuel particles) with and without K Basin sludge addition. The testing described in this report consisted of 12 tests. In 10 of the tests, 4.3 to 26.4 g of fuel particles of selected size distribution were placed into 60- or 800-ml reaction vessels with 0 to 100 g settled sludge. In another test, a single 3.72-g fuel fragment (i.e., 7150-mm particle) was placed in a 60 ml reaction vessel with no added sludge. The twelfth test contained only sludge. The fuel particles were prepared by crushing archived coupons (samples) from an irradiated metallic uranium fuel element. After loading the sludge materials (whether fuel particles, mixtures of fuel particles and sludge, or sludge-only) into reaction vessels, the solids were covered with an excess of K Basin water, the vessels closed and connected to a gas measurement manifold, and the vessels back-flushed with inert neon cover gas. The vessels were then heated to a constant temperature. The gas pressures and temperatures were monitored continuously from the times the vessels were purged. Gas samples were collected at various times during the tests, and the samples analyzed by mass spectrometry. Data on the reaction rates of uranium metal fuel particles with water as a function of temperature and particle size were generated. The data were compared with published studies on metallic uranium corrosion kinetics. The effects of an intimate overlying sludge layer

Performance limits of coated particle fuel. Part I. The significance of empirical performance diagrams and mathematical models in fuel development and power reactor studies

Energy Technology Data Exchange (ETDEWEB)

Graham, L. W.; Hick, H.

1973-06-15

This report introduces a general survey of our present knowledge and understanding of coated particle fuel performance. It defines first the reference power reactor conditions and the reference coated particle design on which the survey is centred. It describes then the typical strategy which has been followed in coated particle fuel development by the Dragon Project R & D Branch. Finally it shows the priorities which have governed the time scale and scope of fuel development and of the present review.

EVALUATION OF THE IMPACT OF OIL PRESENCE IN THE AVIATION FUEL ON PARTICLE SIZE DISTRIBUTION

Directory of Open Access Journals (Sweden)

Remigiusz JASIŃSKI

2017-03-01

Full Text Available Emissions from aircraft engines represent a highly complex and important issue, which is related to the risk to human health. Particles emitted in urban areas and in the vicinity of airports affect air quality and have a particularly negative impact on airport workers. The development of measurement techniques and the methodology for evaluating exhaust emissions have allowed for the elaboration of appropriate procedures for the certification of aircraft and the enhancement of existing standards. Particulate matter emissions depend, among other things, on the composition of the fuel used and its additives. Some aircraft engine designs require a fuel additive in the form of oil, which ensures the proper operation of the fuel supply system. This article presents the results of studies conducted on jet engines powered by clean aviation fuel and fuel with the addition of oil. The aim of the study was to evaluate the effect of the addition of oil on the size distribution and concentration of emitted particles. It was found that, for small values of thrust, oil additive increases the concentration of particles. With an increase in the thrust force, the reduction of particles concentration was recorded in the case of the engine powered by fuel with oil additive. There was no significant effect of oil additive on the size distribution of emitted particles.

New developments in image-based characterization of coated particle nuclear fuel

Science.gov (United States)

Price, Jeffery R.; Aykac, Deniz; Hunn, John D.; Kercher, Andrew K.; Morris, Robert N.

2006-02-01

We describe in this paper new developments in the characterization of coated particle nuclear fuel using optical microscopy and digital imaging. As in our previous work, we acquire optical imagery of the fuel pellets in two distinct manners that we refer to as shadow imaging and cross-sectional imaging. In shadow imaging, particles are collected in a single layer on an optically transparent dish and imaged using collimated back-lighting to measure outer surface characteristics only. In cross-sectional imaging, particles are mounted in acrylic epoxy and polished to near-center to reveal the inner coating layers for measurement. For shadow imaging, we describe a curvaturebased metric that is computed from the particle boundary points in the FFT domain using a low-frequency parametric representation. We also describe how missing boundary points are approximated using band-limited interpolation so that the FFT can be applied. For cross-section imaging, we describe a new Bayesian-motivated segmentation scheme as well as a new technique to correct layer measurements for the fact that we cannot observe the true mid-plane of the approximately spherical particles.

Particle and NO{sub x} Emissions from a HVO-Fueled Diesel Engine

Energy Technology Data Exchange (ETDEWEB)

Happonen, M.

2012-10-15

Concerns about oil price, the strengthening climate change and traffic related health effects are all reasons which have promoted the research of renewable fuels. One renewable fuel candidate is diesel consisting of hydrotreated vegetable oils (HVO). The fuel is essentially paraffinic, has high cetane number (>80) and contains practically no oxygen, aromatics or sulphur. Furthermore, HVO fuel can be produced from various feedstocks including palm, soybean and rapeseed oils as well as animal fats. HVO has also been observed to reduce all regulated engine exhaust emissions compared to conventional diesel fuel. In this thesis, the effect of HVO fuel on engine exhaust emissions has been studied further. The thesis is roughly divided into two parts. The first part explores the emission reductions associated with the fuel and studies techniques which could be applied to achieve further emission reductions. One of the studied techniques was adjusting engine settings to better suit HVO fuel. The settings chosen for adjustments were injection pressure, injection timing, the amount of EGR and the timing of inlet valve closing (with constant inlet air mass flow, i.e. Miller timing). The engine adjustments were also successfully targeted to reduce either NO{sub x} or particulate emissions or both. The other applied emission reduction technique was the addition of oxygenate to HVO fuel. The chosen oxygenate was di-n-pentyl ether (DNPE), and tested fuel blend included 20 wt-% DNPE and 80 wt-% HVO. Thus, the oxygen content of the resulting blend was 2 wt-%. Reductions of over 25 % were observed in particulate emissions with the blend compared to pure HVO while NOx emissions altered under 5 %. On the second part of this thesis, the effect of the studied fuels on chosen surface properties of exhaust particles were studied using tandem differential mobility analyzer (TDMA) techniques and transmission electron microscopy (TEM). The studied surface properties were oxidizability and

Automatic X-ray inspection for escaped coated particles in spherical fuel elements of high temperature gas-cooled reactor

International Nuclear Information System (INIS)

Yang, Min; Liu, Qi; Zhao, Hongsheng; Li, Ziqiang; Liu, Bing; Li, Xingdong; Meng, Fanyong

2014-01-01

As a core unit of HTGRs (high-temperature gas-cooled reactors), the quality of spherical fuel elements is directly related to the safety and reliability of HTGRs. In line with the design and performance requirements of the spherical fuel elements, no coated fuel particles are permitted to enter the fuel-free zone of a spherical fuel element. For fast and accurate detection of escaped coated fuel particles, X-ray DR (digital radiography) imaging with a step-by-step circular scanning trajectory was adopted for Chinese 10 MW HTGRs. The scanning parameters dominating the volume of the blind zones were optimized to ensure the missing detection of the escaped coated fuel particles is as low as possible. We proposed a dynamic calibration method for tracking the projection of the fuel-free zone accurately, instead of using a fuel-free zone mask of fixed size and position. After the projection data in the fuel-free zone were extracted, image and graphic processing methods were combined for automatic recognition of escaped coated fuel particles, and some practical inspection results were presented. - Highlights: • An X-ray DR imaging system for quality inspection of spherical fuel elements was introduced. • A method for optimizing the blind-zone-related scanning parameter was proposed. • A dynamic calibration method for tracking the fuel-free zone accurately was proposed. • Some inspection results of the disqualified spherical fuel elements with escaped coated fuel particles were presented

Code-B-1 for stress/strain calculation for TRISO fuel particle (Contract research)

International Nuclear Information System (INIS)

Aihara, Jun; Ueta, Shohei; Shibata, Taiju; Sawa, Kazuhiro

2011-12-01

We have developed Code-B-1 for the prediction of the failure probabilities of the coated fuel particles for the high temperature gas-cooled reactors (HTGRs) under operation by modification of an existing code. A finite element method (FEM) is employed for the stress calculation part and Code-B-1 can treat the plastic deformation of the coating layer of the coated fuel particles which the existing code cannot treat. (author)

DEM simulation of particle mixing for optimizing the overcoating drum in HTR fuel fabrication

Science.gov (United States)

Liu, Malin; Lu, Zhengming; Liu, Bing; Shao, Youlin

2013-06-01

The rotating drum was used for overcoating coated fuel particles in HTR fuel fabrication process. All the coated particles should be adhered to equal amount of graphite powder, which means that the particle should be mixed quickly in both radial and axial directions. This paper investigated the particle flow dynamics and mixing behavior in different regimes using the discrete element method (DEM). By varying the rotation speed, different flow regimes such as slumping, rolling, cascading, cataracting, centrifuging were produced. The mixing entropy based on radial and axial grid was introduced to describe the radial and axial mixing behaviors. From simulation results, it was found that the radial mixing can be achieved in the cascading regime more quickly than the slumping, rolling and centrifuging regimes, but the traditional rotating drum without internal components can not achieve the requirements of axial mixing and should be improved. Three different structures of internal components are proposed and simulated. The new V-shaped deflectors were found to achieve a quick axial mixing behavior and uniform axial distribution in the rotating drum based on simulation results. At last, the superiority was validated by experimental results, and the new V-shaped deflectors were used in the industrial production of the overcoating coated fuel particles in HTR fuel fabrication process.

Burn-up calculations for a thorium HTR with one and with two types of fuel particle

Energy Technology Data Exchange (ETDEWEB)

Griggs, C. F.

1975-06-15

Cell burn-up calculations have been made on a thorium pin-cell operating with one or with two types of particle. With one particle, the input thorium and uranium are mixed prior to irradiation and all discharged uranium is recycled. With two particles, the fuel is kept in two streams and only the uranium generated from thorium is recycled. The two models are found to give similar power generations from a given initial U-235 input. The choice between the two types of particle is probably not determined by reactor physics considerations but by the value of the fuel credits and by the cost of fuel fabrication and reprocessing.

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)

Determination of uranium in coated fuel particle compact by potassium fluoride fusion-gravimetric method

International Nuclear Information System (INIS)

Ito, Mitsuo; Iso, Shuichi; Hoshino, Akira; Suzuki, Shuichi.

1992-03-01

Potassium fluoride-gravimetric method has been developed for the determination of uranium in TRISO type-coated fuel particle compact. Graphite matrix in the fuel compact is burned off by heating it in a platinum crucible at 850degC. The coated fuel particles thus obtained are decomposed by fusion with potassium fluoride at 900degC. The melt was dissolved with sulfuric acid. Uranium is precipitated as ammonium diuranate, by passing ammonia gas through the solution. The resulting precipitate is heated in a muffle furnace at 850degC, to convert uranium into triuranium octoxide. Uranium in the triuranium octoxide was determined gravimetrically. Ten grams of caoted fuel particles were completely decomposed by fusion with 50 g of potassium fluoride at 900degC for 3 hrs. Analytical result for uranium in the fuel compact by the proposed method was 21.04 ± 0.05 g (n = 3), and was in good agreement with that obtained by non-destructive γ-ray measurement method : 21.01 ± 0.07 g (n = 3). (author)

Army Demonstration of Light Obscuration Particle Counters for Monitoring Aviation Fuel Contamination

Science.gov (United States)

2013-05-07

Hydraulic industry has utilized this technology for decades and created a mature process •Hydraulic industry has developed recognized calibration ...Vehicle Fuel Tank Fuel Injector Aviation Fuel DEF (AUST) 5695B 18/16/13 Parker 18/16/13 14/10/7 Pamas/Parker/Particle Solutions 19/17/12 U.S. Army 19...17/14/13* Diesel Fuel World Wide Fuel Charter 4th 18/16/13 DEF (AUST) 5695B 18/16/13 Bosch/Cummins 18/16/13 Donaldson 22/21/18 14/13/11 12/9/6 P ll

Moisture desorption in mechanically masticated fuels: effects of particle fracturing and fuelbed compaction

Science.gov (United States)

Jesse K. Kreye; J.Morgan Varner; Eric E. Knapp

2012-01-01

Mechanical mastication is increasingly used as a wildland fuel treatment, reducing standing trees and shrubs to compacted fuelbeds of fractured woody fuels. One major shortcoming in our understanding of these fuelbeds is how particle fracturing influences moisture gain or loss, a primary determinant of fire behaviour. To better understand fuel moisture dynamics, we...

Automatic particle-size analysis of HTGR nuclear fuel microspheres

International Nuclear Information System (INIS)

Mack, J.E.

1977-01-01

An automatic particle-size analyzer (PSA) has been developed at ORNL for measuring and counting samples of nuclear fuel microspheres in the diameter range of 300 to 1000 μm at rates in excess of 2000 particles per minute, requiring no sample preparation. A light blockage technique is used in conjunction with a particle singularizer. Each particle in the sample is sized, and the information is accumulated by a multi-channel pulse height analyzer. The data are then transferred automatically to a computer for calculation of mean diameter, standard deviation, kurtosis, and skewness of the distribution. Entering the sample weight and pre-coating data permits calculation of particle density and the mean coating thickness and density. Following this nondestructive analysis, the sample is collected and returned to the process line or used for further analysis. The device has potential as an on-line quality control device in processes dealing with spherical or near-spherical particles where rapid analysis is required for process control

Pressure analysis in the fabrication process of TRISO UO2-coated fuel particle

International Nuclear Information System (INIS)

Liu Malin; Shao Youlin; Liu Bing

2012-01-01

Highlights: ► The pressure signals during the real TRISO UO2-coated fuel particle fabrication process. ► A new relationship about the pressure drop change and the coated fuel particles properties. ► The proposed relationship is validated by experimental results during successive coating. ► A convenient method for monitoring the fluidized state during coating process. - Abstract: The pressure signals in the coating furnace are obtained experimentally from the TRISO UO 2 -coated fuel particle fabrication process. The pressure signals during the coating process are analyzed and a simplified relationship about the pressure drop change due to the coated layer is proposed based on the spouted bed hydrodynamics. The change of pressure drop is found to be consistent with the change of the combination factor about particle density, bed density, particle diameter and static bed height, during the successive coating process of the buffer PyC, IPyC, SiC and OPyC layer. The newly proposed relationship is validated by the experimental values. Based on this relationship, a convenient method is proposed for real-time monitoring the fluidized state of the particles in a high-temperature coating process in the spouted bed. It can be found that the pressure signals analysis is an effective method to monitor the fluidized state on-line in the coating process at high temperature up to 1600 °C.

Method of producing encapsulated thermonuclear fuel particles

International Nuclear Information System (INIS)

Smith, W.H.; Taylor, W.L.; Turner, H.L.

1976-01-01

A method of producing a fuel particle is disclosed, which comprises forming hollow spheroids which have a mass number greater than 50, immersing said spheroids while under the presence of pressure and heat in a gaseous atmosphere containing an isotope, such as deuterium and tritium, so as to diffuse the gas into the spheroid and thereafter cooling said spheroids up to about 77 0 Kelvin to about 4 0 Kelvin. 4 Claims, 3 Drawing Figures

Calculations of IAEA-CRP-6 Benchmark Case 1 through 7 for a TRISO-Coated Fuel Particle

International Nuclear Information System (INIS)

Kim, Young Min; Lee, Y. W.; Chang, J. H.

2005-01-01

IAEA-CRP-6 is a coordinated research program of IAEA on Advances in HTGR fuel technology. The CRP examines aspects of HTGR fuel technology, ranging from design and fabrication to characterization, irradiation testing, performance modeling, as well as licensing and quality control issues. The benchmark section of the program treats simple analytical cases, pyrocarbon layer behavior, single TRISO-coated fuel particle behavior, and benchmark calculations of some irradiation experiments performed and planned. There are totally seventeen benchmark cases in the program. Member countries are participating in the benchmark calculations of the CRP with their own developed fuel performance analysis computer codes. Korea is also taking part in the benchmark calculations using a fuel performance analysis code, COPA (COated PArticle), which is being developed in Korea Atomic Energy Research Institute. The study shows the calculational results of IAEACRP- 6 benchmark cases 1 through 7 which describe the structural behaviors for a single fuel particle

Contributions of fuel combustion to pollution by airborne particles in urban and non-urban environments

International Nuclear Information System (INIS)

1995-06-01

The application of ion beam analysis (IBA) techniques to aerosol pollution problems has been used in a number of countries since the late 1970's and early 1980's. The technique, however, had not been tested in Australia. This document is the final report of a project which aimed to establish a fine particle monitoring network covering the greater Wollongong/Sydney/ Newcastle ares, investigate the relationships between fuel combustion and fine particle aerosols in urban and non urban environments, add to the limited database of baseline information on concentrations of fine particles resulting from such processes as fossil fuel burning and industrial manufacturing, identify and quantify sources of fine particles in New South Wales, and introduce into Australia accelerator based IBA techniques for the analysis of filter papers obtained from large scale monitoring networks. These objectives were addressed by the project which identified and quantified some sources of fine particles and established some relationships between fuel combustion and fine aerosols. More work is required to fully quantify relationships between natural and anthropogenic fine particle sources. 24 tabs., 44 figs., 83 refs

Problems of dosimetry and risk assessment associated with inhalation of fuel particles

International Nuclear Information System (INIS)

Repin, V.S.; Nechaev, S.Y.; Bondarenko, O.A.; Bykorez, A.I.; Kononenko, L.I.

1995-01-01

This work deals with the problems of dosimetry and risk assessment associated with inhalation of fuel particles. Radioactive emission parameters and potential for assessment of the lung cancer risk with inhalation penetration of hot particles are described. (O.L.). 10 refs., 9 figs., 1 tab

Detection and analysis of particles with failed SiC in AGR-1 fuel compacts

Energy Technology Data Exchange (ETDEWEB)

Hunn, John D., E-mail: hunnjd@ornl.gov [Oak Ridge National Laboratory (ORNL), P.O. Box 2008, Oak Ridge, TN 37831-6093 (United States); Baldwin, Charles A.; Gerczak, Tyler J.; Montgomery, Fred C.; Morris, Robert N.; Silva, Chinthaka M. [Oak Ridge National Laboratory (ORNL), P.O. Box 2008, Oak Ridge, TN 37831-6093 (United States); Demkowicz, Paul A.; Harp, Jason M.; Ploger, Scott A. [Idaho National Laboratory (INL), P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States)

2016-09-15

Highlights: • Cesium release was used to detect SiC failure in HTGR fuel. • Tristructural-isotropic particles with SiC failure were isolated by gamma screening. • SiC failure was studied by X-ray tomography and SEM. • SiC degradation was observed after irradiation and subsequent safety testing. - Abstract: As the primary barrier to release of radioactive isotopes emitted from the fuel kernel, retention performance of the SiC layer in tristructural isotropic (TRISO) coated particles is critical to the overall safety of reactors that utilize this fuel design. Most isotopes are well-retained by intact SiC coatings, so pathways through this layer due to cracking, structural defects, or chemical attack can significantly contribute to radioisotope release. In the US TRISO fuel development effort, release of {sup 134}Cs and {sup 137}Cs are used to detect SiC failure during fuel compact irradiation and safety testing because the amount of cesium released by a compact containing one particle with failed SiC is typically ten or more times higher than that released by compacts without failed SiC. Compacts with particles that released cesium during irradiation testing or post-irradiation safety testing at 1600–1800 °C were identified, and individual particles with abnormally low cesium retention were sorted out with the Oak Ridge National Laboratory (ORNL) Irradiated Microsphere Gamma Analyzer (IMGA). X-ray tomography was used for three-dimensional imaging of the internal coating structure to locate low-density pathways through the SiC layer and guide subsequent materialography by optical and scanning electron microscopy. All three cesium-releasing particles recovered from as-irradiated compacts showed a region where the inner pyrocarbon (IPyC) had cracked due to radiation-induced dimensional changes in the shrinking buffer and the exposed SiC had experienced concentrated attack by palladium; SiC failures observed in particles subjected to safety testing were

Milling Behavior of Matrix Graphite Powders with Different Binder Materials in HTGR Fuel Element Fabrication: I. Variation in Particle Size Distribution

International Nuclear Information System (INIS)

Lee, Young Woo; Cho, Moon Sung

2011-01-01

The fuel element for HTGR is manufactured by mixing coated fuel particles with matrix graphite powder and forming into either pebble type or cylindrical type compacts depending on their use in different HTGR cores. The coated fuel particle, the so-called TRISO particle, consists of 500-μm spherical UO 2 particles coated with the low density buffer Pyrolytic Carbon (PyC) layer, the inner and outer high density PyC layer and SiC layer sandwiched between the two inner and outer PyC layers. The coated TRISO particles are mixed with a matrix graphite powder properly prepared and pressed into a spherical shape or a cylindrical compact finally heat-treated at about 1900 .deg. C. These fuel elements can have different sizes and forms of compact. The basic steps for manufacturing a fuel element include preparation of graphite matrix powder, overcoating the fuel particles, mixing the fuel particles with a matrix powder, carbonizing green compact, and the final high-temperature heat treatment of the carbonized fuel compact. In order to develop a fuel compact fabrication technology, it is important to develop a technology to prepare the matrix graphite powder (MGP) with proper characteristics, which has a strong influence on further steps and the material properties of fuel element. In this work, the milling behavior of matrix graphite powder mixture with different binder materials and their contents was investigated by analyzing the change in particle size distribution with different milling time

Effect of the relationship between particle size, inter-particle distance, and metal loading of carbon supported fuel cell catalysts on their catalytic activity

Science.gov (United States)

Corradini, Patricia Gon; Pires, Felipe I.; Paganin, Valdecir A.; Perez, Joelma; Antolini, Ermete

2012-09-01

The effect of the relationship between particle size ( d), inter-particle distance ( x i ), and metal loading ( y) of carbon supported fuel cell Pt or PtRu catalysts on their catalytic activity, based on the optimum d (2.5-3 nm) and x i / d (>5) values, was evaluated. It was found that for y fuel cell electrode than that using catalysts with y ethanol oxidation on PtRu/C catalysts with same particle size and same degree of alloying but different metal loading. Tests in direct ethanol fuel cells showed that, compared to 20 wt% PtRu/C, the negative effect of the lower x i / d on the catalytic activity of 30 and 40 wt% PtRu/C catalysts was superior to the positive effect of the thinner catalyst layer.

Microscopic analysis of irradiated AGR-1 coated particle fuel compacts

Energy Technology Data Exchange (ETDEWEB)

Ploger, Scott A., E-mail: scott.ploger@inl.gov [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3855 (United States); Demkowicz, Paul A. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3855 (United States); Hunn, John D.; Kehn, Jay S. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6093 (United States)

2014-05-01

The AGR-1 experiment involved irradiation of 72 TRISO-coated particle fuel compacts to a peak compact-average burnup of 19.5% FIMA with no in-pile failures observed out of 3 × 10{sup 5} total particles. Irradiated AGR-1 fuel compacts have been cross-sectioned and analyzed with optical microscopy to characterize kernel, buffer, and coating behavior. Six compacts have been examined, spanning a range of irradiation conditions (burnup, fast fluence, and irradiation temperature) and including all four TRISO coating variations irradiated in the AGR-1 experiment. The cylindrical specimens were sectioned both transversely and longitudinally, then polished to expose from 36 to 79 individual particles near midplane on each mount. The analysis focused primarily on kernel swelling and porosity, buffer densification and fracturing, buffer–IPyC debonding, and fractures in the IPyC and SiC layers. Characteristic morphologies have been identified, 981 particles have been classified, and spatial distributions of particle types have been mapped. No significant spatial patterns were discovered in these cross sections. However, some trends were found between morphological types and certain behavioral aspects. Buffer fractures were found in 23% of the particles, and these fractures often resulted in unconstrained kernel protrusion into the open cavities. Fractured buffers and buffers that stayed bonded to IPyC layers appear related to larger pore size in kernels. Buffer–IPyC interface integrity evidently factored into initiation of rare IPyC fractures. Fractures through part of the SiC layer were found in only four classified particles, all in conjunction with IPyC–SiC debonding. Compiled results suggest that the deliberate coating fabrication variations influenced the frequencies of IPyC fractures and IPyC–SiC debonds.

Stress Calculation of a TRISO Coated Particle Fuel by Using a Poisson's Ratio in Creep Condition

International Nuclear Information System (INIS)

Cho, Moon-Sung; Kim, Y. M.; Lee, Y. W.; Jeong, K. C.; Kim, Y. K.; Oh, S. C.; Kim, W. K.

2007-01-01

KAERI, which has been carrying out the Korean VHTR (Very High Temperature modular gas cooled Reactor) project since 2004, has been developing a performance analysis code for the TRISO coated particle fuel named COPA (COated Particle fuel Analysis). COPA predicts temperatures, stresses, a fission gas release and failure probabilities of a coated particle fuel in normal operating conditions. KAERI, on the other hand, is developing an ABAQUS based finite element(FE) model to cover the non-linear behaviors of a coated particle fuel such as cracking or debonding of the TRISO coating layers. Using the ABAQUS based FE model, verification calculations were carried out for the IAEA CRP-6 benchmark problems involving creep, swelling, and pressure. However, in this model the Poisson's ratio for elastic solution was used for creep strain calculation. In this study, an improvement is made for the ABAQUS based finite element model by using the Poisson's ratio in creep condition for the calculation of the creep strain rate. As a direct input of the coefficient in a creep condition is impossible, a user subroutine for the ABAQUS solution is prepared in FORTRAN for use in the calculations of the creep strain of the coating layers in the radial and hoop directions of the spherical fuel. This paper shows the calculation results of a TRISO coated particle fuel subject to an irradiation condition assumed as in the Miller's publication in comparison with the results obtained from the old FE model used in the CRP-6 benchmark calculations

The influence of design and fuel parameters on the particle emissions from wood pellets combustion. Final report

Energy Technology Data Exchange (ETDEWEB)

Wiinikka, Henrik; Gebart, Rikard [Energy Technology Centre, Piteaa (Sweden)

2005-02-01

Combustion of solid biomass under fixed bed conditions is a common technique to generate heat and power in both small and large scale grate furnaces (domestic boilers, stoves, district heating plants). Unfortunately, combustion of biomass will generate particle emissions containing both large fly ash particles and fine particles that consist of fly ash and soot. The large fly ash particles have been produced from fusion of non-volatile ash-forming species in burning char particle. The inorganic fine particles have been produced from nucleation of volatilised ash elements (K, Na, S, Cl and Zn). If the combustion is incomplete, soot particles are also produced from secondary reaction of tar. The particles in the fine fraction grows by coagulation and coalescence to a particle diameter around 0.1 pm. Since the smallest particles are very hard to collect in ordinary cleaning devices they contribute to the ambient air pollution. Furthermore, fine airborne particles have been correlated to adverse effects on the human health. It is therefore essential to minimize particle formation from the combustion process and thereby reduce the emissions of particulates to the ambient air. The aim with this project is to study particle emissions from small scale combustion of wood pellets and to investigate the impact of different operating, construction and fuel parameters on the amount and characteristic of the combustion generated particles. To address these issues, experiments were carried out in a 10 kW updraft fired wood pellets reactor that has been custom designed for systematic investigations of particle emissions. In the flue gas stack, particle emissions were sampled on a filter. The particle mass and number size distributions were analysed by a low pressure cascade impactor and a SMPS (Scanning Electron Mobility Particle Sizer). The results showed that the temperature and the flow pattern in the combustion zone affect the particle emissions. Increasing combustion

Fission product retention in TRISO coated UO2 particle fuels subjected to HTR simulated core heating tests

International Nuclear Information System (INIS)

Baldwin, C.A.; Kania, M.J.

1991-01-01

Results of the examination and analysis of 25,730 individual microspheres from spherical fuel elements HFR-K3/1 and HFR-K3/3 are reported. The parent spheres were irradiated in excess of end-of-life exposure and subsequently subjected to simulated core heating tests in a special high-temperature furnace at Forschungszentrum, Juelich, GmbH (KFA). Following the heating tests, the spheres were electrolytically deconsolidated to obtain unbounded fuel particles for Irradiated Microsphere Gamma Analyzer (IMGA) analysis. For sphere HFR-K3/1, which was heated for 500 h at 1600 deg. C, only four particles were identified as having released fission products. The remaining particles from the sphere showed no statistical evidence of fission product release. Scanning Electron Microscopy (SEM) examination showed that three of the defect particles had large sections of the TRISO coating missing, while the fourth appeared normal. For sphere HFR-K3/3, which was heated for 100 h at 1800 deg. C, the IMGA data revealed that fission product release (cesium) from individual particles was significant and that there was large particle-to-particle variation in retention capabilities. Individual particle release (cesium) averaged ten times the KFA-measured integral spherical fuel element release value. In addition, the bimodal distribution of the individual particle data indicated that two distinct modes of failure at fuel temperatures of 1800 deg. C and above may exist. (author). 6 refs, 6 figs, 4 tabs

Fission product retention in TRISCO coated UO2 particle fuels subjected to HTR simulated core heating tests

International Nuclear Information System (INIS)

Baldwin, C.A.; Kania, M.J.

1990-11-01

Results of the examination and analysis of 25,730 individual microspheres from spherical fuel elements HFR-K3/1 and HFR-K3/3 are reported. The parent spheres were irradiated in excess of end-of-life exposure and subsequently subjected to simulated core heating tests in a special high-temperature furnace at Forschungszentrum, Juelich, GmbH (KFA). Following the heating tests, the spheres were electrolytically deconsolidated to obtain unbonded fuel particles for Irradiated Microsphere Gamma Analyzer (IMGA) analysis. For sphere HFR-K3/1, which was heated for 500 h at 1600 degree C, only four particles were identified as having released fission products. The remaining particles from the sphere showed no statistical evidence of fission product release. Scanning Electron Microscopy (SEM) examination showed that three of the defect particles had large sections of the TRISO coating missing, while the fourth appeared normal. For sphere HFR-K3/3, which was heated for 100 h at 1800 degree C, the IMGA data revealed that fission product release (cesium) from individual particles was significant and that there was large particle-to-particle variation in retention capabilities. Individual particle release (cesium) averaged ten times the KFA-measured integral spherical fuel element release value. In addition, the bimodal distribution of the individual particle data indicated that two distinct modes of failure at fuel temperatures of 1800 degree C and above may exist. 6 refs., 6 figs., 4 tabs

The significance of strength of silicon carbide for the mechanical integrity of coated fuel particles for HTRs

International Nuclear Information System (INIS)

Bongartz, K.; Scheer, A.; Schuster, H.; Taeuber, K.

1975-01-01

Silicon carbide (SiC) and pyrocarbon are used as coating material for the HTR fuel particles. The PyC shell having a certain strength acts as a pressure vessel for the fission gases whereas the SiC shell has to retain the solid fission products in the fuel kernel. For measuring the strength of coating material the so-called Brittle Ring Test was developed. Strength and Young's modulus can be measured simultaneously with this method on SiC or PyC rings prepared out of the coating material of real fuel particles. The strength measured on the ring under a certain stress distribution which is characteristic for this method is transformed with the aid of the Weibull formalism for brittle fracture into the equivalent strength of the spherical coating shell on the fuel particle under uniform stress caused by the fission gas pressure. The values measured for the strength of the SiC were high (400-700MN/m 2 ), it could therefore be assumed that a SiC layer might contribute significantly also to the mechanical strength of the fuel coating. This assumption was confirmed by an irradiation test on coated particles with PyC-SiC-PyC coatings. There were several particles with all PyC layers broken during the irradiation, whereas the SiC layers remained intact having to withstand the fission gas pressure alone. This fact can only be explained assuming that the strength of the SiC is within the range of the values measured with the brittle ring test. The result indicates that, in optimising the coating of a fuel particle, the PyC layers of a multilayer coating should be considered alone as prospective layers for the SiC. The SiC shell, besides acting as a fission product barrier, is then also responsible for the mechanical integrity of the particle

Detection and Analysis of Particles with Failed SiC in AGR-1 Fuel Compacts

International Nuclear Information System (INIS)

Hunn, John D.; Baldwin, Charles A.; Gerczak, Tyler J.; Montgomery, Fred C.; Morris, Robert N.; Silva, Chinthaka M.; Demkowicz, Paul A.; Harp, Jason M.; Ploger, Scott A.

2014-01-01

As the primary barrier to release of radioactive isotopes emitted from the fuel kernel, retention performance of the SiC layer in tristructural isotropic (TRISO) coated particles is critical to the overall safety of reactors that utilize this fuel design. Most isotopes are well-retained by intact SiC coatings, so pathways through this layer due to cracking, structural defects, or chemical attack can significantly contribute to radioisotope release. In the US TRISO fuel development effort, release of "1"3"4Cs and "1"3"7Cs are used to detect SiC failure during fuel compact irradiation and safety testing because the amount of cesium released by a compact containing one particle with failed SiC is typically ten or more times higher than that released by compacts without failed SiC. Compacts with particles that released cesium during the AGR-1 irradiation test or post-irradiation safety testing at 1600– 1800°C were identified, and individual particles with abnormally low cesium retention were sorted out with the ORNL Irradiated Microsphere Gamma Analyzer (IMGA). X-ray tomography was used for three-dimensional imaging of the internal coating structure to locate low-density pathways through the SiC layer and guide subsequent materialography by optical and scanning electron microscopy. All three cesium-releasing particles recovered from as-irradiated compacts showed a region where the inner pyrocarbon (IPyC) had cracked due to radiation-induced dimensional changes in the shrinking buffer and the exposed SiC had experienced concentrated attack by palladium; SiC failures observed in particles subjected to safety testing were related to either fabrication defects or showed extensive Pd corrosion through the SiC where it had been exposed by similar IPyC cracking. (author)

Characterisation of TRISO fuel particles

International Nuclear Information System (INIS)

Lopez H, E.; Yang, D.

2012-10-01

The TRISO (tri structural isotropic) coated fuel particle is a key component contributing to the inherent safety of the High Temperature Reactor. A uranium kernel is coated with three layers of pyrolytic carbon and one of silicon carbide. The purpose of these coatings is to work as a miniature fission product containment vessel capable of enclosing all important radio nuclei under normal and off-normal reactor operating conditions. Due to the importance of these coatings, is of great interest to establish characterisation techniques capable of providing a detailed description of their microstructure and physical properties. Here we describe the use of Raman spectroscopy and two modulator generalised ellipsometry to study the anisotropy and thermal conductivity of pyrolytic carbon coatings, as well as the stoichiometry of the silicon carbide coatings and fibres. (Author)

Measurement of particle size distribution and mass concentration of nuclear fuel aerosols

International Nuclear Information System (INIS)

Pickering, S.

1982-01-01

The particle size distribution and particle mass concentration of a nuclear fuel aerosol is measured by admitting the aerosol into a vertically-extending container, positioning an alpha particle detector within the container so that its window is horizontal and directed vertically, stopping the admission of aerosol into the container, detecting the alpha-activity of the particles of the aerosol sedimenting onto the detector window (for example in a series of equal time intervals until a constant level is reached), and converting the alpha-activity measurements into particle size distribution and/or particle mass concentration measurements. The detector is attached to a pivotted arm and by raising a counterweight can be lowered from the container for cleaning. (author)

Encapsulation of TRISO particle fuel in durable soda-lime-silicate glasses

International Nuclear Information System (INIS)

Heath, Paul G.; Corkhill, Claire L.; Stennett, Martin C.; Hand, Russell J.; Meyer, Willem C.H.M.; Hyatt, Neil C.

2013-01-01

Tri-Structural Isotropic (TRISO) coated particle-fuel is a key component in designs for future high temperature nuclear reactors. This study investigated the suitability of three soda lime silicate glass compositions, for the encapsulation of simulant TRISO particle fuel. A cold press and sinter (CPS) methodology was employed to produce TRISO particle–glass composites. Composites produced were determined to have an aqueous durability, fracture toughness and Vickers’ hardness comparable to glasses currently employed for the disposal of high level nuclear wastes. Sintering at 700 °C for 30 min was found to remove all interconnected porosity from the composite bodies and oxidation of the outer pyrolytic carbon layer during sintering was prevented by processing under a 5% H 2 /N 2 atmosphere. However, the outer pyrolytic carbon layer was not effectively wetted by the encapsulating glass matrix. The aqueous durability of the TRISO particle–glass composites was investigated using PCT and MCC-1 tests combined with geochemical modelling. It was found that durability was dependent on silicate and calcium solution saturation. This study provides significant advancements in the preparation of TRISO particle encapsulant waste forms. The potential for the use of non-borosilicate sintered glass composites for TRISO particle encapsulation has been confirmed, although further refinements are required

Encapsulation of TRISO particle fuel in durable soda-lime-silicate glasses

Energy Technology Data Exchange (ETDEWEB)

Heath, Paul G.; Corkhill, Claire L.; Stennett, Martin C.; Hand, Russell J. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, Robert Hadfield Building, University of Sheffield, Sheffield S1 3JD (United Kingdom); Meyer, Willem C.H.M. [Necsa, South African Nuclear Energy Corporation, PO Box 582, Pretoria, Gauteng (South Africa); Hyatt, Neil C., E-mail: n.c.hyatt@sheffield.ac.uk [Immobilisation Science Laboratory, Department of Materials Science and Engineering, Robert Hadfield Building, University of Sheffield, Sheffield S1 3JD (United Kingdom)

2013-05-15

Tri-Structural Isotropic (TRISO) coated particle-fuel is a key component in designs for future high temperature nuclear reactors. This study investigated the suitability of three soda lime silicate glass compositions, for the encapsulation of simulant TRISO particle fuel. A cold press and sinter (CPS) methodology was employed to produce TRISO particle–glass composites. Composites produced were determined to have an aqueous durability, fracture toughness and Vickers’ hardness comparable to glasses currently employed for the disposal of high level nuclear wastes. Sintering at 700 °C for 30 min was found to remove all interconnected porosity from the composite bodies and oxidation of the outer pyrolytic carbon layer during sintering was prevented by processing under a 5% H{sub 2}/N{sub 2} atmosphere. However, the outer pyrolytic carbon layer was not effectively wetted by the encapsulating glass matrix. The aqueous durability of the TRISO particle–glass composites was investigated using PCT and MCC-1 tests combined with geochemical modelling. It was found that durability was dependent on silicate and calcium solution saturation. This study provides significant advancements in the preparation of TRISO particle encapsulant waste forms. The potential for the use of non-borosilicate sintered glass composites for TRISO particle encapsulation has been confirmed, although further refinements are required.

Aqueous alteration of VHTR fuels particles under simulated geological conditions

Energy Technology Data Exchange (ETDEWEB)

Ait Chaou, Abdelouahed, E-mail: aitchaou@subatech.in2p3.fr; Abdelouas, Abdesselam; Karakurt, Gökhan; Grambow, Bernd

2014-05-01

Very High Temperature Reactor (VHTR) fuels consist of the bistructural-isotropic (BISO) or tristructural-isotropic (TRISO)-coated particles embedded in a graphite matrix. Management of the spent fuel generated during VHTR operation would most likely be through deep geological disposal. In this framework we investigated the alteration of BISO (with pyrolytic carbon) and TRISO (with SiC) particles under geological conditions simulated by temperatures of 50 and 90 °C and in the presence of synthetic groundwater. Solid state (scanning electron microscopy (SEM), micro-Raman spectroscopy, electron probe microanalyses (EPMA) and X-ray photoelectron spectroscopy (XPS)) and solution analyses (ICP-MS, ionique chromatography (IC)) showed oxidation of both pyrolytic carbon and SiC at 90 °C. Under air this led to the formation of SiO{sub 2} and a clay-like Mg–silicate, while under reducing conditions (H{sub 2}/N{sub 2} atmosphere) SiC and pyrolytic carbon were highly stable after a few months of alteration. At 50 °C, in the presence and absence of air, the alteration of the coatings was minor. In conclusion, due to their high stability in reducing conditions, HTR fuel disposal in reducing deep geological environments may constitute a viable solution for their long-term management.

Improvement in retention of solid fission products in HTGR fuel particles by ceramic kernel additives

International Nuclear Information System (INIS)

Foerthmann, R.; Groos, E.; Gruebmeier, H.

1975-08-01

Increased requirements concerning the retention of long-lived solid fission products in fuel elements for use in advanced High Temperature Gas-cooled Reactors led to the development of coated particles with improved fission product retention of the kernel, which represent an alternative to silicon carbide-coated fuel particles. Two irradiation experiments have shown that the release of strontium, barium, and caesium from pyrocarbon-coated particles can be reduced by orders of magnitude if the oxide kernel contains alumina-silica additives. It was detected by electron microprobe analysis that the improved retention of the mentioned fission products in the fuel kernel is caused by formation of the stable aluminosilicates SrAl 2 Si 2 O 8 , BaAl 2 Si 2 O 8 and CsAlSi 2 O 6 in the additional aluminasilica phase of the kernel. (orig.) [de

HTGR fuel particle crusher: Mark 2 design

Energy Technology Data Exchange (ETDEWEB)

Baer, J.W.

1979-06-01

The double-roll crusher for fracturing the silicon carbide coatings of high-temperature gas-cooled reactor (HTGR) fuel particles has been redesigned to improve the equipment. The housing was simplified and reduced to a two-piece assembly; the bearings were changed to accommodate thermal effects; the bearing protection seals were improved with triple redundancy; the bearing preload arrangement was simplified and improved; and localized wear areas were reinforced with better materials or special treatment. In addition, the crusher drive was changed for impoved characteristics and an increase in power.

HTGR fuel particle crusher: Mark 2 design

International Nuclear Information System (INIS)

Baer, J.W.

1979-06-01

The double-roll crusher for fracturing the silicon carbide coatings of high-temperature gas-cooled reactor (HTGR) fuel particles has been redesigned to improve the equipment. The housing was simplified and reduced to a two-piece assembly; the bearings were changed to accommodate thermal effects; the bearing protection seals were improved with triple redundancy; the bearing preload arrangement was simplified and improved; and localized wear areas were reinforced with better materials or special treatment. In addition, the crusher drive was changed for impoved characteristics and an increase in power

Structures of the particles of the condensed dispersed phase in solid fuel combustion products plasma

International Nuclear Information System (INIS)

Samaryan, A.A.; Chernyshev, A.V.; Nefedov, A.P.; Petrov, O.F.; Fortov, V.E.; Mikhailov, Yu.M.; Mintsev, V.B.

2000-01-01

The results of experimental investigations of a type of dusty plasma which has been least studied--the plasma of solid fuel combustion products--were presented. Experiments to determine the parameters of the plasma of the combustion products of synthetic solid fuels with various compositions together with simultaneous diagnostics of the degree of ordering of the structures of the particles of the dispersed condensed phase were performed. The measurements showed that the charge composition of the plasma of the solid fuels combustion products depends strongly on the easily ionized alkali-metal impurities which are always present in synthetic fuel in one or another amount. An ordered arrangement of the particles of a condensed dispersed phase in structures that form in a boundary region between the high-temperature and condensation zones was observed for samples of aluminum-coated solid fuels with a low content of alkali-metal impurities

Development of Improved Models and Designs for Coated-Particle Gas Reactor Fuels (I-NERI Annual Report)

International Nuclear Information System (INIS)

Petti, David Andrew; Maki, John Thomas; Languille, Alain; Martin, Philippe; Ballinger, Ronald

2002-01-01

The objective of this INERI project is to develop improved fuel behavior models for gas reactor coated particle fuels and to develop improved coated-particle fuel designs that can be used reliably at very high burnups and potentially in fast gas-cooled reactors. Thermomechanical, thermophysical, and physiochemical material properties data were compiled by both the US and the French and preliminary assessments conducted. Comparison between U.S. and European data revealed many similarities and a few important differences. In all cases, the data needed for accurate fuel performance modeling of coated particle fuel at high burnup were lacking. The development of the INEEL fuel performance model, PARFUME, continued from earlier efforts. The statistical model being used to simulate the detailed finite element calculations is being upgraded and improved to allow for changes in fuel design attributes (e.g. thickness of layers, dimensions of kernel) as well as changes in important material properties to increase the flexibility of the code. In addition, modeling of other potentially important failure modes such as debonding and asphericity was started. A paper on the status of the model was presented at the HTR-2002 meeting in Petten, Netherlands in April 2002, and a paper on the statistical method was submitted to the Journal of Nuclear Material in September 2002. Benchmarking of the model against Japanese and an older DRAGON irradiation are planned. Preliminary calculations of the stresses in a coated particle have been calculated by the CEA using the ATLAS finite element model. This model and the material properties and constitutive relationships will be incorporated into a more general software platform termed Pleiades. Pleiades will be able to analyze different fuel forms at different scales (from particle to fuel body) and also handle the statistical variability in coated particle fuel. Diffusion couple experiments to study Ag and Pd transport through SiC were

Auxiliary plasma heating and fueling models for use in particle simulation codes

International Nuclear Information System (INIS)

Procassini, R.J.; Cohen, B.I.

1989-01-01

Computational models of a radiofrequency (RF) heating system and neutral-beam injector are presented. These physics packages, when incorporated into a particle simulation code allow one to simulate the auxiliary heating and fueling of fusion plasmas. The RF-heating package is based upon a quasilinear diffusion equation which describes the slow evolution of the heated particle distribution. The neutral-beam injector package models the charge exchange and impact ionization processes which transfer energy and particles from the beam to the background plasma. Particle simulations of an RF-heated and a neutral-beam-heated simple-mirror plasma are presented. 8 refs., 5 figs

Improvement in retention of solid fission products in HTGR fuel particles by ceramic kernel additives

Energy Technology Data Exchange (ETDEWEB)

Foerthmann, R.; Groos, E.; Gruebmeier, H.

1975-08-15

Increased requirements concerning the retention of long-lived solid fission products in fuel elements for use in advanced High Temperature Gas-cooled Reactors led to the development of coated particles with improved fission product retention which represent an alternative to silicon carbide-coated fuel particles. Two irradiation experiments have shown that the release of strontium, barium, and caesium from pyrocarbon-coated particles can be reduced by orders of magnitude if the oxide kernel contains alumina-silica additives. It was detected by electron microprobe analysis that the improved retention of the mentioned fission products in the fuel kernel is caused by formation of the stable aluminosilicates SrAl₂Si₂O₈, BaAl₂Si₂O₈and CsAlSi₂O₆ in the additional alumina-silica phase of the kernel.

A comparative study of the number and mass of fine particles emitted with diesel fuel and marine gas oil (MGO)

Science.gov (United States)

Nabi, Md. Nurun; Brown, Richard J.; Ristovski, Zoran; Hustad, Johan Einar

2012-09-01

The current investigation reports on diesel particulate matter emissions, with special interest in fine particles from the combustion of two base fuels. The base fuels selected were diesel fuel and marine gas oil (MGO). The experiments were conducted with a four-stroke, six-cylinder, direct injection diesel engine. The results showed that the fine particle number emissions measured by both SMPS and ELPI were higher with MGO compared to diesel fuel. It was observed that the fine particle number emissions with the two base fuels were quantitatively different but qualitatively similar. The gravimetric (mass basis) measurement also showed higher total particulate matter (TPM) emissions with the MGO. The smoke emissions, which were part of TPM, were also higher for the MGO. No significant changes in the mass flow rate of fuel and the brake-specific fuel consumption (BSFC) were observed between the two base fuels.

A Small Modular Reactor Core Design using FCM Fuel and BISO BP particles

Energy Technology Data Exchange (ETDEWEB)

Choi, Jae Yeon; Hwang, Dae Hee; Yoo, Ho Seong; Hong, Ser Gi [Kyung Hee University, Yongin (Korea, Republic of)

2016-10-15

The objective of this work is to design a PWR small modular reactor which employs the advanced fuel technology of FCM particle fuels including BISO burnable poisons and advanced cladding of SiC in order to improve the fuel economy and safety by increasing fuel burnup and temperature, and by reducing hydrogen generation under accidents. Recently, many countries including USA have launched projects to develop the accident tolerant fuels (ATF) which can cope with the accidents such as LOCA (Loss of Coolant Accident). In general, the ATF fuels are required to meet the PWR operational, safety, and fuel cycle constraints which include enhanced burnup, lower or no generation of hydrogen, lower operating temperatures, and enhanced retention of fission products. Another stream of research and development in nuclear society is to develop advanced small modular reactors in order to improve inherent passive safety and to reduce the risk of large capital investment. In this work, a small PWR modular reactor core was neutronically designed and analyzed. The SMR core employs new 13x13 fuel assemblies which are loaded with thick FCM fuel rods in which TRISO fuel particles AO and also the first cycle has the AOs which are within the typical design limit. Also, this figure shows that the evolutions of AO for the cycles 6 and 7 are nearly the same. we considered the SiC cladding for reduction of hydrogen generation under accidents. From the results of core design and analysis, it is shown that the core has long cycle length of 732 -1191 EFPDs, high discharge burnup of 101-105 MWD/kg, low power peaking factors, low axial offsets, negative MTCs, and large shutdown margins except for BOC of the first cycle. So, it can be concluded that the new SMR core is neutronically feasible.

A Small Modular Reactor Core Design using FCM Fuel and BISO BP particles

International Nuclear Information System (INIS)

Choi, Jae Yeon; Hwang, Dae Hee; Yoo, Ho Seong; Hong, Ser Gi

2016-01-01

The objective of this work is to design a PWR small modular reactor which employs the advanced fuel technology of FCM particle fuels including BISO burnable poisons and advanced cladding of SiC in order to improve the fuel economy and safety by increasing fuel burnup and temperature, and by reducing hydrogen generation under accidents. Recently, many countries including USA have launched projects to develop the accident tolerant fuels (ATF) which can cope with the accidents such as LOCA (Loss of Coolant Accident). In general, the ATF fuels are required to meet the PWR operational, safety, and fuel cycle constraints which include enhanced burnup, lower or no generation of hydrogen, lower operating temperatures, and enhanced retention of fission products. Another stream of research and development in nuclear society is to develop advanced small modular reactors in order to improve inherent passive safety and to reduce the risk of large capital investment. In this work, a small PWR modular reactor core was neutronically designed and analyzed. The SMR core employs new 13x13 fuel assemblies which are loaded with thick FCM fuel rods in which TRISO fuel particles AO and also the first cycle has the AOs which are within the typical design limit. Also, this figure shows that the evolutions of AO for the cycles 6 and 7 are nearly the same. we considered the SiC cladding for reduction of hydrogen generation under accidents. From the results of core design and analysis, it is shown that the core has long cycle length of 732 -1191 EFPDs, high discharge burnup of 101-105 MWD/kg, low power peaking factors, low axial offsets, negative MTCs, and large shutdown margins except for BOC of the first cycle. So, it can be concluded that the new SMR core is neutronically feasible

Oxide particle size distribution from shearing irradiated and unirradiated LWR fuels in Zircaloy and stainless steel cladding: significance for risk assessment

International Nuclear Information System (INIS)

Davis, W. Jr.; West, G.A.; Stacy, R.G.

1979-01-01

Sieve fractionation was performed with oxide particles dislodged during shearing of unirradiated or irradiated fuel bundles or single rods of UO 2 or 96 to 97% ThO 2 --3 to 4% UO 2 . Analyses of these data by nonlinear least-squares techniques demonstrated that the particle size distribution is lognormal. Variables involved in the numerical analyses include lognormal median size, lognormal standard deviation, and shear cut length. Sieve-fractionation data are presented for unirradiated bundles of stainless-steel-clad or Zircaloy-2-clad UO 2 or ThO 2 --UO 2 sheared into lengths from 0.5 to 2.0 in. Data are also presented for irradiated single rods (sheared into lengths of 0.25 to 2.0 in.) of Zircaloy-2-clad UO 2 from BWRs and of Zircaloy-4-clad UO 2 from PWRs. Median particle sizes of UO 2 from shearing irradiated stainless-steel-clad fuel ranged from 103 to 182 μm; particle sizes of ThO 2 --UO 2 , under these same conditions, ranged from 137 to 202 μm. Similarly, median particle sizes of UO 2 from shearing unirradiated Zircaloy-2-clad fuel ranged from 230 to 957 μm. Irradiation levels of fuels from reactors ranged from 9,000 to 28,000 MWd/MTU. In general, particle sizes from shearing these irradiated fuels are larger than those from the unirradiated fuels. In addition, variations in particle size parameters pertaining to samples of a single vendor varied as much as those between different vendors. The fraction of fuel dislodged from the cladding is nearly proportional to the reciprocal of the shear cut length, until the cut length attains some minimum value below which all fuel is dislodged. Particles of fuel are generally elongated with a long-to-short axis ratio usually less than 3. Using parameters of the lognormal distribution deduced from experimental data, realistic estimates can be made of fractions of dislodged fuel having dimensions less than specified values

Fission product behavior in HTGR fuel particles made from weak-acid resins

International Nuclear Information System (INIS)

Tiegs, T.N.; Henson, T.J.

1979-04-01

Fission product retention and behavior are of utmost importance in HTGR fuel particles. The present study concentrates on particles made from weak-acid resins, which can vary in composition from 100% UO 2 plus excess carbon to 100% UC 2 plus excess carbon. Five compositions were tested: UC 4 58 O 2 04 , UC 3 68 O 0 01 , UC 4 39 O 1 72 , UC 4 63 O 0 97 , and UC 4 14 O 1 53 . Metallographically sectioned particles were examined with a shielded electron microprobe. The distributions of the fission products were determined by monitoring characteristic x-ray lines while scanning the electron beam over the particle surface

A study on coated particle fuel properties and performances and phase-I data base establishment

International Nuclear Information System (INIS)

Kim, Yong Soo; Lee, Hyo Cheol; Im, Byeong Ju; Yun, Sang Pil; Son, Seung Beom; Lee, Gyeong Hui; Jang, Jeong Nam

2006-03-01

For the successful development of the high temperature gas cooled reactor acquisition and generation of the high temperature properties of reactor materials, especially temperature and burn-up dependent properties of coated particle fuel and fuel element, are crucially essential. Recently national project for HTGR for hydrogen production has been kicked off. However, we have had little experience on this new challenges. Therefore, it became necessary to build up the materials properties and fuel performance data base. In this study, a primitive properties and performance DB for coated particle fuel was developed. This database report consists two sections: materials properties and fuel performance. The materials properties has three parts: kernel materials, carbide coating materials, and fuel elements and graphite matrix. UO 2 and UCO belong to kernel materials while PyC, SiC, and ZrC comprises the coating materials section. Thermal, mechanical and physical properties of these materials were collected, reviewed, and summarized. Additionally, the property change induced by manufacture process and irradiation were collected and summarized. Performance data were also collected, reviewed, and analyzed based on the key phenomena and failure mechanism. All of these data will be accessible in the on-line system. These results will be directly used for HTGR fuel design and fabrication and preliminary fuel performance analysis under irradiation

Error Analysis of Ceramographic Sample Preparation for Coating Thickness Measurement of Coated Fuel Particles

International Nuclear Information System (INIS)

Liu Xiaoxue; Li Ziqiang; Zhao Hongsheng; Zhang Kaihong; Tang Chunhe

2014-01-01

The thicknesses of four coatings of HTR coated fuel particle are very important parameters. It is indispensable to control the thickness of four coatings of coated fuel particles for the safety of HTR. A measurement method, ceramographic sample-microanalysis method, to analyze the thickness of coatings was developed. During the process of ceramographic sample-microanalysis, there are two main errors, including ceramographic sample preparation error and thickness measurement error. With the development of microscopic techniques, thickness measurement error can be easily controlled to meet the design requirements. While, due to the coated particles are spherical particles of different diameters ranged from 850 to 1000μm, the sample preparation process will introduce an error. And this error is different from one sample to another. It’s also different from one particle to another in the same sample. In this article, the error of the ceramographic sample preparation was calculated and analyzed. Results show that the error introduced by sample preparation is minor. The minor error of sample preparation guarantees the high accuracy of the mentioned method, which indicates this method is a proper method to measure the thickness of four coatings of coated particles. (author)

Carbon Nanostructure of Diesel Soot Particles Emitted from 2 and 4 Stroke Marine Engines Burning Different Fuels.

Science.gov (United States)

Lee, Won-Ju; Park, Seul-Hyun; Jang, Se-Hyun; Kim, Hwajin; Choi, Sung Kuk; Cho, Kwon-Hae; Cho, Ik-Soon; Lee, Sang-Min; Choi, Jae-Hyuk

2018-03-01

Diesel soot particles were sampled from 2-stroke and 4-stroke engines that burned two different fuels (Bunker A and C, respectively), and the effects of the engine and fuel types on the structural characteristics of the soot particle were analyzed. The carbon nanostructures of the sampled particles were characterized using various techniques. The results showed that the soot sample collected from the 4-stroke engine, which burned Bunker C, has a higher degree of order of the carbon nanostructure than the sample collected from the 2-stroke engine, which burned Bunker A. Furthermore, the difference in the exhaust gas temperatures originating from the different engine and fuel types can affect the nanostructure of the soot emitted from marine diesel engines.

Comparison of stochastic models in Monte Carlo simulation of coated particle fuels

International Nuclear Information System (INIS)

Yu Hui; Nam Zin Cho

2013-01-01

There is growing interest worldwide in very high temperature gas cooled reactors as candidates for next generation reactor systems. For design and analysis of such reactors with double heterogeneity introduced by the coated particle fuels that are randomly distributed in graphite pebbles, stochastic transport models are becoming essential. Several models were reported in the literature, such as coarse lattice models, fine lattice stochastic (FLS) models, random sequential addition (RSA) models, metropolis models. The principles and performance of these stochastic models are described and compared in this paper. Compared with the usual fixed lattice methods, sub-FLS modeling allows more realistic stochastic distribution of fuel particles and thus results in more accurate criticality calculation. Compared with the basic RSA method, sub-FLS modeling requires simpler and more efficient overlapping checking procedure. (authors)

Effects of fuel components and combustion particle physicochemical properties on toxicological responses of lung cells.

Science.gov (United States)

Jaramillo, Isabel C; Sturrock, Anne; Ghiassi, Hossein; Woller, Diana J; Deering-Rice, Cassandra E; Lighty, JoAnn S; Paine, Robert; Reilly, Christopher; Kelly, Kerry E

2018-03-21

The physicochemical properties of combustion particles that promote lung toxicity are not fully understood, hindered by the fact that combustion particles vary based on the fuel and combustion conditions. Real-world combustion-particle properties also continually change as new fuels are implemented, engines age, and engine technologies evolve. This work used laboratory-generated particles produced under controlled combustion conditions in an effort to understand the relationship between different particle properties and the activation of established toxicological outcomes in human lung cells (H441 and THP-1). Particles were generated from controlled combustion of two simple biofuel/diesel surrogates (methyl decanoate and dodecane/biofuel-blended diesel (BD), and butanol and dodecane/alcohol-blended diesel (AD)) and compared to a widely studied reference diesel (RD) particle (NIST SRM2975/RD). BD, AD, and RD particles exhibited differences in size, surface area, extractable chemical mass, and the content of individual polycyclic aromatic hydrocarbons (PAHs). Some of these differences were directly associated with different effects on biological responses. BD particles had the greatest surface area, amount of extractable material, and oxidizing potential. These particles and extracts induced cytochrome P450 1A1 and 1B1 enzyme mRNA in lung cells. AD particles and extracts had the greatest total PAH content and also caused CYP1A1 and 1B1 mRNA induction. The RD extract contained the highest relative concentration of 2-ring PAHs and stimulated the greatest level of interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNFα) cytokine secretion. Finally, AD and RD were more potent activators of TRPA1 than BD, and while neither the TRPA1 antagonist HC-030031 nor the antioxidant N-acetylcysteine (NAC) affected CYP1A1 or 1B1 mRNA induction, both inhibitors reduced IL-8 secretion and mRNA induction. These results highlight that differences in fuel and combustion conditions

Oxide particle size distribution from shearing irradiated and unirradiated LWR fuels in Zircaloy and stainless steel cladding: significance for risk assessment

Energy Technology Data Exchange (ETDEWEB)

Davis, W. Jr.; West, G.A.; Stacy, R.G.

1979-03-22

Sieve fractionation was performed with oxide particles dislodged during shearing of unirradiated or irradiated fuel bundles or single rods of UO/sub 2/ or 96 to 97% ThO/sub 2/--3 to 4% UO/sub 2/. Analyses of these data by nonlinear least-squares techniques demonstrated that the particle size distribution is lognormal. Variables involved in the numerical analyses include lognormal median size, lognormal standard deviation, and shear cut length. Sieve-fractionation data are presented for unirradiated bundles of stainless-steel-clad or Zircaloy-2-clad UO/sub 2/ or ThO/sub 2/--UO/sub 2/ sheared into lengths from 0.5 to 2.0 in. Data are also presented for irradiated single rods (sheared into lengths of 0.25 to 2.0 in.) of Zircaloy-2-clad UO/sub 2/ from BWRs and of Zircaloy-4-clad UO/sub 2/ from PWRs. Median particle sizes of UO/sub 2/ from shearing irradiated stainless-steel-clad fuel ranged from 103 to 182 ..mu..m; particle sizes of ThO/sub 2/--UO/sub 2/, under these same conditions, ranged from 137 to 202 ..mu..m. Similarly, median particle sizes of UO/sub 2/ from shearing unirradiated Zircaloy-2-clad fuel ranged from 230 to 957 ..mu..m. Irradiation levels of fuels from reactors ranged from 9,000 to 28,000 MWd/MTU. In general, particle sizes from shearing these irradiated fuels are larger than those from the unirradiated fuels; however, unirradiated fuel from vendors was not available for performing comparative shearing experiments. In addition, variations in particle size parameters pertaining to samples of a single vendor varied as much as those between different vendors. The fraction of fuel dislodged from the cladding is nearly proportional to the reciprocal of the shear cut length, until the cut length attains some minimum value below which all fuel is dislodged. Particles of fuel are generally elongated with a long-to-short axis ratio usually less than 3. Using parameters of the lognormal distribution estimates can be made of fractions of dislodged fuel having

Analysis of irradiation-induced stresses in coating layers of coated fuel particles for the High Temperature Engineering Test Reactor (HTTR)

International Nuclear Information System (INIS)

Hayashi, Kimio; Kikuchi, Teruo; Fukuda, Kousaku; Sato, Sadao; Toyota, Junji; Shiozawa, Shusaku; Sawa, Kazuhiro; Kashimura, Satoru.

1991-07-01

Irradiation-induced stresses in coating layers of coated fuel particles were analyzed by the MICROS-2 code for the fuels of the High Temperature Engineering Test Reactor (HTTR) under its operating conditions. The analyses were made on the standard core fuel (A-type) and the test fuels comprising the advanced SiC-coated particle fuel (B-1 type) and the ZrC-coated particle fuel (B-2 type). For the B-1 type fuel, the stresses were relieved due to the thicker buffer and SiC layers than for the A type fuel. The slightly decreased thickness of the fourth layer for the B-1 type than for the A type fuel had no significant effect on the stresses. As for the B-2 type fuel, almost the same results as for the B-1 type were obtained under an assumption that the ZrC layer as well as the SiC layer undergoes negligible dimension change within the analysis conditions. The obtained results indicated that the B-1 and B-2 type fuels are better than the A type fuel in terms of integrity against the irradiation-induced stresses. Finally, research subjects for development of the analysis code on the fuel behavior are discussed. (author)

Some calculations of the failure statistics of coated fuel particles

International Nuclear Information System (INIS)

Martin, D.G.; Hobbs, J.E.

1977-03-01

Statistical variations of coated fuel particle parameters were considered in stress model calculations and the resulting particle failure fraction versus burn-up evaluated. Variations in the following parameters were considered simultaneously: kernel diameter and porosity, thickness of the buffer, seal, silicon carbide and inner and outer pyrocarbon layers, which were all assumed to be normally distributed, and the silicon carbide fracture stress which was assumed to follow a Weibull distribution. Two methods, based respectively on random sampling and convolution of the variations were employed and applied to particles manufactured by Dragon Project and RFL Springfields. Convolution calculations proved the more satisfactory. In the present calculations variations in the silicon carbide fracture stress caused the greatest spread in burn-up for a given change in failure fraction; kernel porosity is the next most important parameter. (author)

Coating Thickness Measurement of the Simulated TRISO-Coated Fuel Particles using an Image Plate and a High Resolution Scanner

International Nuclear Information System (INIS)

Kim, Woong Ki; Kim, Yeon Ku; Jeong, Kyung Chai; Lee, Young Woo; Kim, Bong Goo; Eom, Sung Ho; Kim, Young Min; Yeo, Sung Hwan; Cho, Moon Sung

2014-01-01

In this study, the thickness of the coating layers of 196 coated particles was measured using an Image Plate detector, high resolution scanner and digital image processing techniques. The experimental results are as follows. - An X-ray image was acquired for 196 simulated TRISO-coated fuel particles with ZrO 2 kernel using an Image Plate with high resolution in a reduced amount of time. - We could observe clear boundaries between coating layers for 196 particles. - The geometric distortion error was compensated for the calculation. - The coating thickness of the TRISO-coated fuel particles can be nondestructively measured using X-ray radiography and digital image processing technology. - We can increase the number of TRISO-coated particles to be inspected by increasing the number of Image Plate detectors. A TRISO-coated fuel particle for an HTGR (high temperature gas-cooled reactor) is composed of a nuclear fuel kernel and outer coating layers. The coating layers consist of buffer PyC (pyrolytic carbon), inner PyC (I-PyC), SiC, and outer PyC (O-PyC) layer. The coating thickness is measured to evaluate the soundness of the coating layers. X-ray radiography is one of the nondestructive alternatives for measuring the coating thickness without generating a radioactive waste. Several billion particles are subject to be loaded in a reactor. A lot of sample particles should be tested as much as possible. The acquired X-ray images for the measurement of coating thickness have included a small number of particles because of the restricted resolution and size of the X-ray detector. We tried to test many particles for an X-ray exposure to reduce the measurement time. In this experiment, an X-ray image was acquired for 196 simulated TRISO-coated fuel particles using an image plate and high resolution scanner with a pixel size of 25Χ25 μm 2 . The coating thickness for the particles could be measured on the image

Thermo-mechanical behaviour modelling of particle fuels using a multi-scale approach

International Nuclear Information System (INIS)

Blanc, V.

2009-12-01

Particle fuels are made of a few thousand spheres, one millimeter diameter large, compound of uranium oxide coated by confinement layers which are embedded in a graphite matrix to form the fuel element. The aim of this study is to develop a new simulation tool for thermo-mechanical behaviour of those fuels under radiations which is able to predict finely local loadings on the particles. We choose to use the square finite element method, in which two different discretization scales are used: a macroscopic homogeneous structure whose properties in each integration point are computed on a second heterogeneous microstructure, the Representative Volume Element (RVE). First part of this works is concerned by the definition of this RVE. A morphological indicator based in the minimal distance between spheres centers permit to select random sets of microstructures. The elastic macroscopic response of RVE, computed by finite element has been compared to an analytical model. Thermal and mechanical representativeness indicators of local loadings has been built from the particle failure modes. A statistical study of those criteria on a hundred of RVE showed the significance of choose a representative microstructure. In this perspective, a empirical model binding morphological indicator to mechanical indicator has been developed. Second part of the work deals with the two transition scale method which are based on the periodic homogenization. Considering a linear thermal problem with heat source in permanent condition, one showed that the heterogeneity of the heat source involve to use a second order method to localized finely the thermal field. The mechanical non-linear problem has been treats by using the iterative Cast3M algorithm, substituting to integration of the behavior law a finite element computation on the RVE. This algorithm has been validated, and coupled with thermal resolution in order to compute a radiation loading. A computation on a complete fuel element

Mass-spectrometric determination in individual coated HTR fuel particles

International Nuclear Information System (INIS)

Strigl, A.

1976-11-01

A method is described which allows the simultaneous determination of fission and reaction gases in individual coated particles at temperatures up to 2000 0 C. The particles are heated under high-vacuum in a micro resistance-furnace up to the desired temperature. After preselected times the particles are crushed by action of a pneumatic cylinder. The gases liberated are fed into a quadrupoleanalyzer where they are analyzed in a dynamic mode. A peak selector allows the simultaneous measurement of up to four gases. The method is used routinely for the determination of fission gases (Kr and Xe) and of carbon monoxide which is formed as a reaction gas from oxide fuel. Precision and accuracy are in the order of a few percent. Detection limits for routine measurements are about 10 -7 cm 3 (STP) for KR and Xe and 2 x 10 -5 cm 3 (STP) for CO but can be lowered by special techniques. (author)

Fuel Property, Emission Test, and Operability Results from a Fleet of Class 6 Vehicles Operating on Gas-to-Liquid Fuel and Catalyzed Diesel Particle Filters

Energy Technology Data Exchange (ETDEWEB)

Alleman, T. L.; Eudy, L.; Miyasato, M.; Oshinuga, A.; Allison, S.; Corcoran, T.; Chatterjee, S.; Jacobs, T.; Cherrillo, R. A.; Clark, R.; Virrels, I.; Nine, R.; Wayne, S.; Lansing, R.

2005-11-01

A fleet of six 2001 International Class 6 trucks operating in southern California was selected for an operability and emissions study using gas-to-liquid (GTL) fuel and catalyzed diesel particle filters (CDPF). Three vehicles were fueled with CARB specification diesel fuel and no emission control devices (current technology), and three vehicles were fueled with GTL fuel and retrofit with Johnson Matthey's CCRT diesel particulate filter. No engine modifications were made.

Fission product Pd-SiC interaction in irradiated coated particle fuels

International Nuclear Information System (INIS)

Tiegs, T.N.

1980-04-01

Silicon carbide is the main barrier to fission product release from coated particle fuels. Consequently, degradation of the SiC must be minimized. Electron microprobe analysis has identified that palladium causes corrosion of the SiC in irradiated coated particles. Further ceramographic and electron microprobe examinations on irradiated particles with kernels ranging in composition from UO 2 to UC 2 , including PuO/sub 2 -x/ and mixed (Th, Pu) oxides, and in enrichment from 0.7 to 93.0% 235 U revealed that temperature is the major factor affecting the penetration rate of SiC by Pd. The effects of kernel composition, Pd concentration, other fission products, and SiC properties are secondary

Interaction of Al2O3xSiO2 alloyed uranium oxide with pyrocarbon coating of fuel particles under irradiation

International Nuclear Information System (INIS)

Chernikov, A.S.; Khromov, Yu.F.; Svistunov, D.E.; Chujko, E.E.

1989-01-01

Method of comparative data analysis for P O2 and P CO was used to consider interaction in fuel particle between pyrocarbon coating and fuel sample, alloyed with alumosilicate addition. Equations of interaction reactions for the case of hermetic and depressurized fuel particle are presented. Calculations of required xAl 2 O 3 XySiO 2 content, depending on oxide fuel burnup, were conducted. It was suggested to use silicon carbide for limitation of the upper level of CO pressure in fuel particle. Estimation of thermal stability of alumosilicates under conditions of uranium oxide burnup equals 1100 and 1500 deg C for Al/Si ratio in addition 1/1 and 4/1 respectively

Advanced Characterization Techniques for Silicon Carbide and Pyrocarbon Coatings on Fuel Particles for High Temperature Reactors (HTR)

Energy Technology Data Exchange (ETDEWEB)

Basini, V.; Charollais, F. [CEA Cadarache, DEN/DEC/SPUA, BP 1, 13108 St Paul Lez Durance (France); Dugne, O. [CEA Marcoule, DEN/DTEC/SCGS BP 17171 30207 Bagnols sur Ceze (France); Garcia, C. [Laboratoire des Composites Thermostructuraux (LCTS), UMR CNRS 5801, 3 allee de La Boetie, 33600 Pessac (France); Perez, M. [CEA Grenoble DRT/DTH/LTH, 17 rue des Martyrs, 38054 Grenoble cedex 9 (France)

2008-07-01

Cea and AREVA NP have engaged an extensive research and development program on HTR (high temperature reactor) fuel. The improving of safety of (very) high temperature reactors (V/HTR) is based on the quality of the fuel particles. This requires a good knowledge of the properties of the four-layers TRISO particles designed to retain the uranium and fission products during irradiation or accident conditions. The aim of this work is to characterize exhaustively the structure and the thermomechanical properties of each unirradiated layer (silicon carbide and pyrocarbon coatings) by electron microscopy (SEM, TEM), selected area electronic diffraction (SEAD), thermo reflectance microscopy and nano-indentation. The long term objective of this study is to define pertinent parameters for fuel performance codes used to better understand the thermomechanical behaviour of the coated particles. (authors)

Effects of fuel particle size and fission-fragment-enhanced irradiation creep on the in-pile behavior in CERCER composite pellets

Energy Technology Data Exchange (ETDEWEB)

Zhao, Yunmei [Institute of Mechanics and Computational Engineering, Department of Aeronautics and Astronautics, Fudan University, Shanghai 200433 (China); Ding, Shurong, E-mail: dsr1971@163.com [Institute of Mechanics and Computational Engineering, Department of Aeronautics and Astronautics, Fudan University, Shanghai 200433 (China); Zhang, Xunchao; Wang, Canglong; Yang, Lei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2016-12-15

The micro-scale finite element models for CERCER pellets with different-sized fuel particles are developed. With consideration of a grain-scale mechanistic irradiation swelling model in the fuel particles and the irradiation creep in the matrix, numerical simulations are performed to explore the effects of the particle size and the fission-fragment-enhanced irradiation creep on the thermo-mechanical behavior of CERCER pellets. The enhanced irradiation creep effect is applied in the 10 μm-thick fission fragment damage matrix layer surrounding the fuel particles. The obtained results indicate that (1) lower maximum temperature occurs in the cases with smaller-sized particles, and the effects of particle size on the mechanical behavior in pellets are intricate; (2) the first principal stress and radial axial stress remain compressive in the fission fragment damage layer at higher burnup, thus the mechanism of radial cracking found in the experiment can be better explained. - Highlights: • A grain-scale gas swelling model considering the development of recrystallization and resolution is adopted for particles. • The influence of fission-gas-induced porosity is considered in the constitutive relations for particles. • A simulation method is developed for the multi-scale thermo-mechanical behavior. • The effects of fuel particle size and fission-fragment-enhanced irradiation creep are investigated in pellets.

Morphology of single inhalable particle inside public transit biodiesel fueled bus.

Science.gov (United States)

Shandilya, Kaushik K; Kumar, Ashok

2010-01-01

In an urban-transit bus, fueled by biodiesel in Toledo, Ohio, single inhalable particle samples in October 2008 were collected and detected by scanning electron microscopy and energy dispersive X-ray spectrometry (SEM/EDS). Particle size analysis found bimodal distribution at 0.2 and 0.5 microm. The particle morphology was characterized by 14 different shape clusters: square, pentagon, hexagon, heptagon, octagon, nonagon, decagon, agglomerate, sphere, triangle, oblong, strip, line or stick, and unknown, by quantitative order. The square particles were common in the samples. Round and triangle particles are more, and pentagon, hexagon, heptagon, octagon, nonagon, decagon, strip, line or sticks are less. Agglomerate particles were found in abundance. The surface of most particles was coarse with a fractal edge that can provide a suitable chemical reaction bed in the polluted atmospheric environment. The three sorts of surface patterns of squares were smooth, semi-smooth, and coarse. The three sorts of square surface patterns represented the morphological characteristics of single inhalable particles in the air inside the bus in Toledo. The size and shape distribution results were compared to those obtained for a bus using ultra low sulfur diesel.

Fuel particle coating data. [Detailed information on coating runs at Los Alamos Scientific Laboratory

Energy Technology Data Exchange (ETDEWEB)

Hollabaugh, C.M.; Wagner, P.; Wahman, L.A.; White, R.W.

1977-01-01

Development of coating on nuclear fuel particles for the High-Temperature Fuels Technology program at the Los Alamos Scientific Laboratory included process studies for low-density porous and high-density isotropic carbon coats, and for ZrC and ''alloy'' C/ZrC coats. This report documents the data generated by these studies.

Rheology of Colombian coal-water slurry fuels: Effect of particle-size distribution

Energy Technology Data Exchange (ETDEWEB)

Pulido, J E; Rojas, C P; Acero, G [Universidad Industrial de Santander, Bucaramanga (Colombia)

1996-12-31

Coal-water slurry fuels (CWSF`s) have been prepared and characterized in a research project in Colombia, sponsored by Colciencias and Ecocarbon, in order to evaluate the effects of the different composition variables on the behavior during preparation and pipe line transportation. The authors have previously presented details describing the characteristics of the slurry fuels prepared with five types of Colombian thermal coals and the influence of their chemical composition on the optimum particle-size distribution (PSD) required to prepare highly loaded and workable CWSF`s. The formulation and design of flow systems of suspensions with high solids content, such as the CWSF`s, require a detailed rheological knowledge of the suspension in terms of the governing parameters related to PSD, coal content, surface chemistry of the particles and dispersants used to stabilize the slurries. Important studies on these aspects have been reviewed and carried out experimentally by other authors specially devoted to the correlations between apparent viscosity, solids content and average coal particle-size. One of the targets to obtain an optimum control on the viscosity and flow properties of the CWSF`s must be based in correlating the Theological constants for the prevailing model of viscosity law to the characteristic parameters of the particle-size distribution and to the coal content in the slurry. In spite of the effect of PSD on the rheology of highly-loaded coal slurries have been long recognized as significant, the specific influence of the various PSD`s on the parameters of the Theological model continues to receive attention to further understanding in order to improve the slurry formulations for a specified purpose on preparation and hydraulic handling. This paper reports the results of an experimental technique of examining the various PSD`s on coal slurry fuel rheology, taking special attention for the effect on the parameters of the rheological model.

Stress Analysis of a TRISO Coated Particle Fuel by Using ABAQUS Finite Element Visco-Elastoplastic Solutions

International Nuclear Information System (INIS)

Cho, Moon Sung; Kim, Y. M.; Lee, Y. W.

2006-01-01

The fundamental design for a gas-cooled reactor relies on an understanding of the behavior of a coated particle fuel. KAERI, which has been carrying out the Korean VHTR (Very High Temperature modular gas cooled Reactor) Project since 2004, is developing a fuel performance analysis code for a VHTR named COPA (COated Particle fuel Analysis). A validation of COPA was attempted by comparing its benchmark results with the visco-elastic solutions obtained from the ABAQUS code calculations for the IAEA-CRP-6 TRISO coated particle benchmark problems involving a creep, swelling, and pressure. However, the ABAQUS finite element model used for the above-mentioned analysis did not consider the material nonlinearity of the SiC coating layer that showed stress levels higher than the assumed yield point of the material. In this study, a consideration of the material nonlinearity is included in the ABAQUS model to obtain the visco-elastoplastic solutions and the results are compared with the visco-elastic solutions obtained from the previous ABAQUS model

Device for fracturing silicon-carbide coatings on nuclear-fuel particles

Science.gov (United States)

Turner, L.J.; Willey, M.G.; Tiegs, S.M.; Van Cleve, J.E. Jr.

This invention is a device for fracturing particles. It is designed especially for use in hot cells designed for the handling of radioactive materials. In a typical application, the device is used to fracture a hard silicon-carbide coating present on carbon-matrix microspheres containing nuclear-fuel materials, such as uranium or thorium compounds. To promote remote control and facilitate maintenance, the particle breaker is pneumatically operated and contains no moving parts. It includes means for serially entraining the entrained particles on an anvil housed in a leak-tight chamber. The flow rate of the gas is at a value effecting fracture of the particles; preferably, it is at a value fracturing them into product particulates of fluidizable size. The chamber is provided with an outlet passage whose cross-sectional area decreases in the direction away from the chamber. The outlet is connected tangentially to a vertically oriented vortex-flow separator for recovering the product particulates entrained in the gas outflow from the chamber. The invention can be used on a batch or continuous basis to fracture the silicon-carbide coatings on virtually all of the particles fed thereto.

Method for fracturing silicon-carbide coatings on nuclear-fuel particles

Science.gov (United States)

Turner, Lloyd J.; Willey, Melvin G.; Tiegs, Sue M.; Van Cleve, Jr., John E.

1982-01-01

This invention is a device for fracturing particles. It is designed especially for use in "hot cells" designed for the handling of radioactive materials. In a typical application, the device is used to fracture a hard silicon-carbide coating present on carbon-matrix microspheres containing nuclear-fuel material, such as uranium or thorium compounds. To promote remote control and facilitate maintenance, the particle breaker is pneumatically operated and contains no moving parts. It includes means for serially entraining the entrained particles on an anvil housed in a leak-tight chamber. The flow rate of the gas is at a value effecting fracture of the particles; preferably, it is at a value fracturing them into product particulates of fluidizable size. The chamber is provided with an outlet passage whose cross-sectional area decreases in the direction away from the chamber. The outlet is connected tangentially to a vertically oriented vortex-flow separator for recovering the product particulates entrained in the gas outflow from the chamber. The invention can be used on a batch or continuous basis to fracture the silicon-carbide coatings on virtually all of the particles fed thereto.

Development of Coated Particle Fuel Technology

International Nuclear Information System (INIS)

Lee, Young Woo; Kim, B. G.; Kim, S. H.

2007-06-01

Uranium kernel fabrication technology using a wet chemical so-gel method, a key technology in the coated particle fuel area, is established up to the calcination step and the first sintering of UO2 kernel was attempted. Experiments on the parametric study of the coating process using the surrogate ZrO2 kernel give the optimum conditions for the PyC and SiC coating layer and ZrC coating conditions were obtained for the vaporization of the ZrCl4 precursor and coating condition from ZrC coating experiments using plate-type graphite substrate. In addition, by development of fuel performance analysis code a part of the code system is completed which enables the participation to the benchmark calculation and comparison in the IAEA collaborated research program. The technologies for irradiation and post irradiation examination, which are important in developing the HTGR fuel technology of its first kind in Korea was started to develop and, through a feasibility study and preliminary analysis, the technologies required to be developed are identified for further development as well as the QC-related basic technologies are reviewed, analyzed and identified for the own technology development. Development of kernel fabrication technology can be enhanced for the remaining sintering technology and completed based on the technologies developed in this phase. In the coating technology, the optimum conditions obtained using a surrogate ZrO2 kernel material can be applied for the uranium kernel coating process development. Also, after completion of the code development in the next phase, more extended participation to the international collaboration for benchmark calculation can be anticipated which will enable an improvement of the whole code system. Technology development started in this phase will be more extended and further focused on the detailed technology development to be required for the related technology establishment

Performance limits of coated particle fuel. Part II. Mechanical failure of coated particles due to internal gas pressure and kernel swelling

Energy Technology Data Exchange (ETDEWEB)

Hick, H.; Nabielek, H.; Harrison, T. A.

1973-10-15

This report presents a summary of experimental results and their theoretical explanation with regard to the "Pressure Failure" of coated particle fuel. While the experimental results refer mainly to the Dragon Reference Particle as proposed for typical Low Enriched Homogeneous Prismatic Steam Cycle HTR Power Reactors, the theoretical understanding of the phenomena and the mathematical models for their description are not limited to a specific design line.

Accelerator-Based Irradiation Creep of Pyrolytic Carbon Used in TRISO Fuel Particles for the (VHTR) Very High Temperature Reactors

International Nuclear Information System (INIS)

Wang, Lumin; Was, Gary

2010-01-01

Pyrolytic carbon (PyC) is one of the important structural materials in the TRISO fuel particles which will be used in the next generation of gas-cooled very-high-temperature reactors (VHTR). When the TRISO particles are under irradiation at high temperatures, creep of the PyC layers may cause radial cracking leading to catastrophic particle failure. Therefore, a fundamental understanding of the creep behavior of PyC during irradiation is required to predict the overall fuel performance.

In-pile test results of U-silicide or U-nitride coated U-7Mo particle dispersion fuel in Al

Science.gov (United States)

Kim, Yeon Soo; Park, J. M.; Lee, K. H.; Yoo, B. O.; Ryu, H. J.; Ye, B.

2014-11-01

U-silicide or U-nitride coated U-Mo particle dispersion fuel in Al (U-Mo/Al) was in-pile tested to examine the effectiveness of the coating as a diffusion barrier between the U-7Mo fuel kernels and Al matrix. This paper reports the PIE data and analyses focusing on the effectiveness of the coating in terms of interaction layer (IL) growth and general fuel performance. The U-silicide coating showed considerable success, but it also provided evidence for additional improvement for coating process. The U-nitride coated specimen showed largely inefficient results in reducing IL growth. From the test, important observations were also made that can be utilized to improve U-Mo/Al fuel performance. The heating process for coating turned out to be beneficial to suppress fuel swelling. The use of larger fuel particles confirmed favorable effects on fuel performance.

In-pile test results of U-silicide or U-nitride coated U-7Mo particle dispersion fuel in Al

Energy Technology Data Exchange (ETDEWEB)

Kim, Yeon Soo, E-mail: yskim@anl.gov [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Park, J.M.; Lee, K.H.; Yoo, B.O. [Korea Atomic Energy Research Institute, 989-111 Daedeokdaero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Ryu, H.J. [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Ye, B. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

2014-11-15

U-silicide or U-nitride coated U-Mo particle dispersion fuel in Al (U-Mo/Al) was in-pile tested to examine the effectiveness of the coating as a diffusion barrier between the U-7Mo fuel kernels and Al matrix. This paper reports the PIE data and analyses focusing on the effectiveness of the coating in terms of interaction layer (IL) growth and general fuel performance. The U-silicide coating showed considerable success, but it also provided evidence for additional improvement for coating process. The U-nitride coated specimen showed largely inefficient results in reducing IL growth. From the test, important observations were also made that can be utilized to improve U-Mo/Al fuel performance. The heating process for coating turned out to be beneficial to suppress fuel swelling. The use of larger fuel particles confirmed favorable effects on fuel performance.

Effect of the relationship between particle size, inter-particle distance, and metal loading of carbon supported fuel cell catalysts on their catalytic activity

International Nuclear Information System (INIS)

Gon Corradini, Patricia; Pires, Felipe I.; Paganin, Valdecir A.; Perez, Joelma; Antolini, Ermete

2012-01-01

The effect of the relationship between particle size (d), inter-particle distance (x i ), and metal loading (y) of carbon supported fuel cell Pt or PtRu catalysts on their catalytic activity, based on the optimum d (2.5–3 nm) and x i /d (>5) values, was evaluated. It was found that for y i /d can be always obtained. For y ≥ 30 wt%, instead, the positive effect of a thinner catalyst layer of the fuel cell electrode than that using catalysts with y i /d compared to their optimum values, with in turns gives rise to a decrease in the catalytic activity. The effect of the x i /d ratio has been successfully verified by experimental results on ethanol oxidation on PtRu/C catalysts with same particle size and same degree of alloying but different metal loading. Tests in direct ethanol fuel cells showed that, compared to 20 wt% PtRu/C, the negative effect of the lower x i /d on the catalytic activity of 30 and 40 wt% PtRu/C catalysts was superior to the positive effect of the thinner catalyst layer.

Particle fueling experiments with a series of pellets in LHD

Science.gov (United States)

Baldzuhn, J.; Damm, H.; Dinklage, A.; Sakamoto, R.; Motojima, G.; Yasuhara, R.; Ida, K.; Yamada, H.; LHD Experiment Group; Wendelstein 7-X Team

2018-03-01

Ice pellet injection is performed in the heliotron Large Helical Device (LHD). The pellets are injected in short series, with up to eight individual pellets. Parameter variations are performed for the pellet ice isotopes, the LHD magnetic configurations, the heating scenario, and some others. These experiments are performed in order to find out whether deeper fueling can be achieved with a series of pellets compared to single pellets. An increase of the fueling efficiency is expected since pre-cooling of the plasma by the first pellets within a series could aid deeper penetration of later pellets in the same series. In addition, these experiments show which boundary conditions must be fulfilled to optimize the technique. The high-field side injection of pellets, as proposed for deep fueling in a tokamak, will not be feasible with the same efficiency in a stellarator or heliotron because there the magnetic field gradient is smaller than in a tokamak of comparable size. Hence, too shallow pellet fueling, in particular in a large device or a fusion reactor, will be an issue that can be overcome only by extremely high pellet velocities, or other techniques that will have to be developed in the future. It turned out by our investigations that the fueling efficiency can be enhanced by the injection of a series of pellets to some extent. However, further investigations will be needed in order to optimize this approach for deep particle fueling.

Irradiated-Microsphere Gamma Analyzer (IMGA): an integrated system for HTGR coated particle fuel performance assessment

International Nuclear Information System (INIS)

Kania, M.J.; Valentine, K.H.

1980-02-01

The Irradiated-Microsphere Gamma Analyzer (IMGA) System, designed and built at ORNL, provides the capability of making statistically accurate failure fraction measurements on irradiated HTGR coated particle fuel. The IMGA records the gamma-ray energy spectra from fuel particles and performs quantitative analyses on these spectra; then, using chemical and physical properties of the gamma emitters it makes a failed-nonfailed decision concerning the ability of the coatings to retain fission products. Actual retention characteristics for the coatings are determined by measuring activity ratios for certain gamma emitters such as 137 Cs/ 95 Zr and 144 Ce/ 95 Zr for metallic fission product retention and 134 Cs/ 137 Cs for an indirect measure of gaseous fission product retention. Data from IMGA (which can be put in the form of n failures observed in N examinations) can be accurately described by the binomial probability distribution model. Using this model, a mathematical relationship between IMGA data (n,N), failure fraction, and confidence level was developed. To determine failure fractions of less than or equal to 1% at confidence levels near 95%, this model dictates that from several hundred to several thousand particles must be examined. The automated particle handler of the IMGA system provides this capability. As a demonstration of failure fraction determination, fuel rod C-3-1 from the OF-2 irradiation capsule was analyzed and failure fraction statistics were applied. Results showed that at the 1% failure fraction level, with a 95% confidence level, the fissile particle batch could not meet requirements; however, the fertile particle exceeded these requirements for the given irradiation temperature and burnup

Study on fuel particle motion of a diesel spray; Diesel funmu ryushi no kyodo ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, N. [Isuzu Motors Ltd., Tokyo (Japan); Tsujimura, K.

1998-08-25

This study was performed to clarify the mechanism of mixture formation at peripheral area of diesel spray with PIV technique. Two dimensional cross-sectional photographs of diesel spray were taken with double pulse laser sheet. Local fuel spray particles were analyzed with an auto-correlation method and velocity vector and vorticity of the fuel spray particle were obtained. The vortex number increased and vorticity scale became smaller and its value grew higher with both smaller injection nozzle diameter and higher fuel injection velocity. With this injection condition, the mixing of fuel spray with ambient gas seems to be improved and the turbulence is expected to increase in the regions of higher vortex number, higher vorticity and smaller vorticity scale. Based on above results, the branch-like structure of diesel fuel spray was considered to be caused by vortices which formed in the shear layer between the spray and the ambient gas. 14 refs., 18 figs., 1 tab.

Particle Image Velocimetry and Computational Fluid Dynamics Analysis of Fuel Cell Manifold

DEFF Research Database (Denmark)

Lebæk, Jesper; Blazniak Andreasen, Marcin; Andresen, Henrik Assenholm

2010-01-01

The inlet effect on the manifold flow in a fuel cell stack was investigated by means of numerical methods (computational fluid dynamics) and experimental methods (particle image velocimetry). At a simulated high current density situation the flow field was mapped on a 70 cell simulated cathode...

On transient irradiation behavior of HTGR fuel particles

International Nuclear Information System (INIS)

Mortenson, S.C.; Okrent, D.

1977-01-01

An examination of HTGR TRISO coated fuel particles was made in which the particles' stress-strain histories were determined during both steady-state and transient operating conditions. The basis for the examination was a modified version of a computer code written by Kaae which assumed spherical symmetry, isotropic thermal expansion, isotropic elastic constants, time-temperature-irradiation invariant materials properties, and steady state operation during particle exposure. Additionally, the Kaae code modelled potential separation of layers at the SiC-inner PyC interface and considered that several entrapped fission products could exist in either the gaseous or solid state, dependent upon particle operating conditions. Using the modified code which modelled transient behavior in a quasi-static fashion, a series of both steady-state and transient operating condition computer simulations was made. For the former set of runs, a candidate set of particle dimensions and a nominal set of materials' properties was assumed. Layer thicknesses were assumed to be normally distributed about the nominal thickenesses and a probability distribution of SiC tensile stresses was generated; sensitivity of the stress distribution to assumed standard deviation of the layer thicknesses was acute. Further, this series of steady-state runs demonstrated that for certain combinations of the assumed PyC-SiC bond interface strength and irradiation-induced creep constant, anomalous predicted stresses may be obtained in the PyC layers. The steady-state runs also suggest that transient behavior would most likely not be significant at fast neutron exposures below about 10 21 NVT due to both low fission gas pressure and likely beneficial interface separation

An In-situ materials analysis particle probe (MAPP) diagnostic to study particle density control and hydrogenic fuel retention in NSTX

Energy Technology Data Exchange (ETDEWEB)

Allain, Jean-Paul [Purdue Univ., West Lafayette, IN (United States)

2014-09-05

A new materials analysis particle probe (MAPP) was designed, constructed and tested to develop understanding of particle control and hydrogenic fuel retention in lithium-based plasma-facing surfaces in NSTX. The novel feature of MAPP is an in-situ tool to probe the divertor NSTX floor during LLD and lithium-coating shots with subsequent transport to a post-exposure in-vacuo surface analysis chamber to measure D retention. In addition, the implications of a lithiated graphite-dominated plasma-surface environment in NSTX on LLD performance, operation and ultimately hydrogenic pumping and particle control capability are investigated in this proposal. MAPP will be an invaluable tool for erosion/redeposition simulation code validation.

Mathematical modelling of sewage sludge incineration in a bubbling fluidised bed with special consideration for thermally-thick fuel particles.

Science.gov (United States)

Yang, Yao Bin; Sharifi, Vida; Swithenbank, Jim

2008-11-01

Fluidised bed combustor (FBC) is one of the key technologies for sewage sludge incineration. In this paper, a mathematical model is developed for the simulation of a large-scale sewage sludge incineration plant. The model assumes the bed consisting of a fast-gas phase, an emulsion phase and a fuel particle phase with specific consideration for thermally-thick fuel particles. The model further improves over previous works by taking into account throughflow inside the bubbles as well as the floating and random movement of the fuel particles inside the bed. Validation against both previous lab-scale experiments and operational data of a large-scale industrial plant was made. Calculation results indicate that combustion split between the bed and the freeboard can range from 60/40 to 90/10 depending on the fuel particle distribution across the bed height under the specific conditions. The bed performance is heavily affected by the variation in sludge moisture level. The response time to variation in feeding rate is different for different parameters, from 6 min for outlet H2O, 10 min for O2, to 34 min for bed temperature.

Particle fueling and impurity control in PDX

International Nuclear Information System (INIS)

Fonck, R.J.; Bell, M.; Bol, K.

1984-12-01

Fueling requirements and impurity levels in neutral-beam-heated discharges in the PDX tokamak have been compared for plasmas formed with conventional graphite rail limiters, a particle scoop limiter, and an open or closed poloidal divertor. Gas flows necessary to obtain a given density are highest for diverted discharges and lowest for the scoop limiter. Hydrogen pellet injection provides an efficient alternate fueling technique, and a multiple pellet injector has produced high density discharges for an absorbed neutral beam power of up to 600 kW, above which higher speeds or more massive pellets are required for penetration to the plasma core. Power balance studies indicate that 30 to 40% of the total input power is radiated while approx. 15% is absorbed by the limiting surface, except in the open divertor case, where 60% flows to the neutralizer plate. In all operating configurations, Z/sub eff/ usually rises at the onset of neutral beam injection. Both open divertor plasmas and those formed on a well conditioned water-cooled limiter have Z/sub eff/ less than or equal to 2 at the end of neutral injection. A definitive comparison of divertors and limiters for impurity control purposes requires longer beam pulses or higher power levels than available on present machines

New developments in JET neutron, alpha particle and fuel mixture diagnostics with potential relevance to ITER

International Nuclear Information System (INIS)

Murari, A.; Bertalot, L.; Angelone, M.; Pillon, M.; Ericsson, G.; Conroy, S.; Kaellne, J.; Kiptily, V.; Popovichev, S.; Adams, J.M.; Stork, D.; Afanasyiev, V.; Mironov, M.; Bonheure, G.

2005-01-01

Some recent JET campaigns, with the introduction of trace amount (n T /n D 4 He, provided unique opportunities to test new diagnostic approaches and technologies for the detection of neutrons, alpha particles and fuel mixture. With regard to neutron detection, the recent activity covered all the most essential aspects: calibration and cross validation of the diagnostics, measurement of the spatial distribution of the neutrons, particle transport and finally neutron spectrometry. The first tests of some new neutron detection technologies were also undertaken successfully during the TTE campaign. To improve JET diagnostic capability in the field of alpha particles, a strong development program was devoted to the measurement of their slowing down and imaging with gamma ray spectroscopy. A new approach for the fusion community to measure the fast ion losses, based on the activation technique, was also successfully attempted for the first time on JET. A careful assessment of the NPA potential to determine the fuel mixture and the particle transport coefficients is under way. (author)

Particle and carbon dioxide emissions from passenger vehicles operating on unleaded petrol and LPG fuel

International Nuclear Information System (INIS)

Ristovski, Z.D.; Jayaratne, E.R.; Morawska, L.; Ayoko, G.A.; Lim, M.

2005-01-01

A comprehensive study of the particle and carbon dioxide emissions from a fleet of six dedicated liquefied petroleum gas (LPG) powered and five unleaded petrol (ULP) powered new Ford Falcon Forte passenger vehicles was carried out on a chassis dynamometer at four different vehicle speeds-0 (idle), 40, 60, 80 and 100 km h -1 . Emission factors and their relative values between the two fuel types together with a statistical significance for any difference were estimated for each parameter. In general, LPG was found to be a 'cleaner' fuel, although in most cases, the differences were not statistically significant owing to the large variations between emissions from different vehicles. The particle number emission factors ranged from 10 11 to 10 13 km -1 and was over 70% less with LPG compared to ULP. Corresponding differences in particle mass emission factor between the two fuels were small and ranged from the order of 10 μg km -1 at 40 to about 1000 μg km -1 at 100 km h -1 . The count median particle diameter (CMD) ranged from 20 to 35 nm and was larger with LPG than with ULP in all modes except the idle mode. Carbon dioxide emission factors ranged from about 300 to 400 g km -1 at 40 km h -1 , falling with increasing speed to about 200 g km -1 at 100 km h -1 . At all speeds, the values were 10% to 18% greater with ULP than with LPG

Neutronic calculations of AFPR-100 reactor based on Spherical Cermet Fuel particles

International Nuclear Information System (INIS)

Benchrif, A.; Chetaine, A.; Amsil, H.

2013-01-01

Highlights: • AFPR-100 reactor considered as a small nuclear reactor without on-site refueling originally based on TRISO micro-fuel element. • The AFPR-100 reactor was re-designed using the new Spherical Cermet fuel element. • The adoption of the Cermet fuel instead of TRISO fuel reduces the core lifetime operation by 3.1 equivalent full power years. • We discussed the new micro-fuel element candidate for small and medium sized reactors. - Abstract: The Atoms For Peace Reactor (AFPR-100), as a 100 MW(e) without the need of on-site refueling, was originally based on UO2 TRISO fuel coated particles embedded in a carbon matrix directly cooled by light water. AFPR-100 is considered as a small nuclear reactor without open-vessel refueling which is proposed by Pacific Northwest National Laboratory (PNNL). An account of significant irradiation swelling in the silicon carbide fission product barrier coating layer of TRISO fuel element, a Spherical Cermet Fuel element has been proposed. Indeed, the new fuel concept, which was developed by PNNL, consists of changing the pyro-carbon and ceramic coatings that are incompatible with low temperature by Zirconium. The latter was chosen to avoid any potential Wigner energy effect issues in the TRISO fuel element. Actually, the purpose of this study is to assess the goal of AFPR-100 concept using the Cermet fuel; undeniably, the fuel core lifetime prediction may be extended for reasonably long period without on-site refueling. In fact, we investigated some neutronic parameters of reactor core by the calculation code SRAC95. The results suggest that the core fuel lifetime beyond 12 equivalent full power years (EFPYs) is possible. Hence, the adoption of Cermet fuel concept shows a core lifetime decrease of about 3.1 EFPY

Diffusivities of Ag, Cs, Sr, and Kr in TRISO fuel particles and graphite

Energy Technology Data Exchange (ETDEWEB)

Collin, Blaise Paul [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-09-01

Tri-structural isotropic (TRISO) coated particles have been developed and studied since the late 1950s when the concept of coated particles was invented by Roy Huddle of the United Kingdom Atomic Energy Authority. Several decades of work by half a dozen countries on fission product transport in TRISO fuel through numerous irradiation and heating experiments have led to several recommendations of transport data and to the adoption of various sets of diffusion coefficients. In 1997, the International Atomic Energy Agency (IAEA) gathered all these historical results and issued a technical document (TECDOC-978 [IAEA]) that summarizes these sets of recommended diffusion coefficients. Table 1 shows the reference literature articles for the diffusivities that have historically been recommended by the American and German TRISO fuel development programs and that are summarized in the IAEA report (see section 7 for full references of these articles).

Characterization of airborne plutonium-bearing particles from a nuclear fuel reprocessing plant

International Nuclear Information System (INIS)

Sanders, S.M. Jr.

1977-11-01

The elemental compositions, sizes, structures, and 239 Pu contents were determined for 299 plutonium-bearing particles isolated from airborne particles collected at various locations in the exhaust from a nuclear fuel reprocessing facility. These data were compared with data from natural aerosol particles. Most of the collected particles were composed of aggregates of crustal materials. Seven percent of the particles were organic and 3% were metallic, viz., iron, chromium, and nickel. High enrichment factors for titanium, manganese, chromium, nickel, zinc, and copper were evidence of the anthropic nature of some of the particles. The amount of plutonium in most particles was very small (less than one femtocurie of 239 Pu). Plutonium concentrations were determined by the fission track counting method. Only one particle contained sufficient plutonium for detection by electron microprobe analysis. This was a 1-μm-diameter particle containing 73% PuO 2 by weight (estimated to be 170 fCi of 239 Pu) in combination with Fe 2 O 3 and mica. The plutonium-bearing particles were generally larger than natural aerosols. The geometric mean diameter of those collected from the mechanical line exhaust point where plutonium is converted to the metal was larger than that of particles collected from the wet cabinet exhaust (13.7 μm vs. 4.6 μm). Particles from the mechanical line also contained more plutonium per particle than those from the wet cabinets

Development of a FE Model for the Stress Analysis of HTGR TRISO-coated particle fuel

International Nuclear Information System (INIS)

Cho, Moon Sung; Lee, Y. W.; Jeong, K. C.; Kim, Y. K.; Oh, S. C.; Chang, J. H.

2005-12-01

Finite element modelling of the stresses in TRISO-coated fuel particle under normal operating conditions was carried out with use of the structural analysis computer code ABAQUS. The FE model took into account the irradiation induced swelling and the creep of the PyC layers, the internal fission gas pressure that builds up during irradiation and the constant external ambient pressure. All of the inputs such as particle dimensions, swelling rates and creep rates of PyC layers and other mechanical properties used in these calculations were adopted from Miller's publication published in 1993. The FE model was verified against Miller's solution. Results of this model were found to be in good agreement with Miller's results. With use of the FE model, the static behavior of the TRISO-coated fuel particle, such as load shares, stress contours, stress variations as a function of fluence and shape changes of the TRISO -coated layers were investigated

Influence of physical and chemical characteristics of diesel fuels and exhaust emissions on biological effects of particle extracts: a multivariate statistical analysis of ten diesel fuels.

Science.gov (United States)

Sjögren, M; Li, H; Banner, C; Rafter, J; Westerholm, R; Rannug, U

1996-01-01

The emission of diesel exhaust particulates is associated with potentially severe biological effects, e.g., cancer. The aim of the present study was to apply multivariate statistical methods to identify factors that affect the biological potency of these exhausts. Ten diesel fuels were analyzed regarding physical and chemical characteristics. Particulate exhaust emissions were sampled after combustion of these fuels on two makes of heavy duty diesel engines. Particle extracts were chemically analyzed and tested for mutagenicity in the Ames test. Also, the potency of the extracts to competitively inhibit the binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to the Ah receptor was assessed. Relationships between fuel characteristics and biological effects of the extracts were studied, using partial least squares regression (PLS). The most influential chemical fuel parameters included the contents of sulfur, certain polycyclic aromatic compounds (PAC), and naphthenes. Density and flash point were positively correlated with genotoxic potency. Cetane number and upper distillation curve points were negatively correlated with both mutagenicity and Ah receptor affinity. Between 61% and 70% of the biological response data could be explained by the measured chemical and physical factors of the fuels. By PLS modeling of extract data versus the biological response data, 66% of the genotoxicity could be explained, by 41% of the chemical variation. The most important variables, associated with both mutagenicity and Ah receptor affinity, included 1-nitropyrene, particle bound nitrate, indeno[1,2,3-cd]pyrene, and emitted mass of particles. S9-requiring mutagenicity was highly correlated with certain PAC, whereas S9-independent mutagenicity was better correlated with nitrates and 1-nitropyrene. The emission of sulfates also showed a correlation both with the emission of particles and with the biological effects. The results indicate that fuels with biologically less hazardous

Applying burnable poison particles to reduce the reactivity swing in high temperature reactors with batch-wise fuel loading

International Nuclear Information System (INIS)

Kloosterman, J.L.; Dam, H. van; Hagen, T.H.J.J. van der

2003-01-01

Burnup calculations have been performed on a standard HTR fuel pebble with a radius of 3 cm containing 9 g of 8% enriched uranium and burnable poison particles (BPP) made of B 4 C highly enriched in 10 B. The radius of the BPP and the number of particles per fuel pebble have been varied to find the flattest reactivity-to-time curve. It was found that for a k∞ of 1.1, a reactivity swing as low as 2% can be obtained when each fuel pebble contains about 1070 BPP with a radius of 75 μm. For coated BPP that consist of a graphite kernel with a radius of 300 μm covered with a B 4 C burnable poison layer, a similar value for the reactivity swing can be obtained. Cylindrical particles seem to perform worse. In general, the modification of the geometry of BPP is an effective means to tailor the reactivity curve of HTRs

Effect of the relationship between particle size, inter-particle distance, and metal loading of carbon supported fuel cell catalysts on their catalytic activity

Energy Technology Data Exchange (ETDEWEB)

Gon Corradini, Patricia; Pires, Felipe I.; Paganin, Valdecir A.; Perez, Joelma, E-mail: jperez@iqsc.usp.br [Instituto de Quimica de Sao Carlos, USP (Brazil); Antolini, Ermete [Scuola di Scienza dei Materiali (Italy)

2012-09-15

The effect of the relationship between particle size (d), inter-particle distance (x{sub i}), and metal loading (y) of carbon supported fuel cell Pt or PtRu catalysts on their catalytic activity, based on the optimum d (2.5-3 nm) and x{sub i}/d (>5) values, was evaluated. It was found that for y < 30 wt%, the optimum values of both d and x{sub i}/d can be always obtained. For y {>=} 30 wt%, instead, the positive effect of a thinner catalyst layer of the fuel cell electrode than that using catalysts with y < 30 wt% is concomitant to a decrease of the effective catalyst surface area due to an increase of d and/or a decrease of x{sub i}/d compared to their optimum values, with in turns gives rise to a decrease in the catalytic activity. The effect of the x{sub i}/d ratio has been successfully verified by experimental results on ethanol oxidation on PtRu/C catalysts with same particle size and same degree of alloying but different metal loading. Tests in direct ethanol fuel cells showed that, compared to 20 wt% PtRu/C, the negative effect of the lower x{sub i}/d on the catalytic activity of 30 and 40 wt% PtRu/C catalysts was superior to the positive effect of the thinner catalyst layer.

Postirradiation examination of HTR fuel

International Nuclear Information System (INIS)

Nabielek, H.; Reitsamer, G.; Kania, M.J.

1986-01-01

Fuel for the High Temperature Reactor (HTR) consists of 1 mm diameter coated particles uniformly distributed in a graphite matrix within a cold-molded 60 mm diameter spherical fuel element. Fuel performance demonstrations under simulated normal operation conditions are conducted in accelerated neutron environments available in Material Test Reactors and in real-time environments such as the Arbeitsgemeinschaft Versuchsreaktor (AVR) Juelich. Postirradiation examinations are then used to assess fuel element behavior and the detailed performance of the coated particles. The emphasis in postirradiation examination and accident testing is on assessment of the capability for fuel elements and individual coated particles to retain fission products and actinide fuel materials. To accomplish this task, techniques have been developed which measures fission product and fuel material distributions within or exterior to the particle: Hot Gas Chlorination - provides an accurate method to measure total fuel material concentration outside intact particles; Profile Electrolytic Deconsolidation - permits determination of fission product distribution along fuel element diameter and retrieval of fuel particles from positions within element; Gamma Spectrometry - provides nondestructive method to measure defect particle fractions based on retention of volatile metallic fission products; Particle Cracking - permits a measure of the partitioning of fission products between fuel kernel and particle coatings, and the derivation of diffusion parameters in fuel materials; Micro Gas Analysis - provides gaseous fission product and reactive gas inventory within free volume of single particles; and Mass-spectrometric Burnup Determination - utilizes isotope dilution for the measurement of heavy metal isotope abundances

Determination of end-of-life-failure fractions of HTGR-fuel particles by postirradiation annealing and beta autoradiography

International Nuclear Information System (INIS)

Thiele, B.A.; Herren, M.

1978-11-01

Fission-product contamination of the helium coolant of High-Temperature Gas-Cooled Reactors (HTGR) is strongly influenced by the end-of-life (EOL) failed-particle fraction. Knowledge of the EOL-failure fraction is the basis for model calculations to predict the total fission product release from the reactor core. After disintegration of irradiation fuel rods, fuel particles are placed in individual holes of a graphite tray. During a 5-h heat treatment at 1000 0 C in a helium atmosphere failed particles leak fission products, especially the volatile cesium, into the graphite. After unloading a β-autoradiograph of the tray is made. Holes that housed defective particles are identified from black spots on the β-sensitive film. The EOL-failure fraction is the ratio of defective particles to the total number of particles tested. The technique is called PIAA, PostIrradiation Annealing and Autoradiography. The PIAA technique was applied to particles of a Trisocoated highly-enriched UO 2 fissile batch irradiated to a burnup of 35% FIMA at an irradiation temperature of 1250 0 C. Visual examination showed all particles to be intact. From 11 to 47% of the particles had failed, as determined by PIAA. Further, postirradiation examination showed that localized corrosion of the silicon carbide coating by fission-product rare-earth chlorides had occurred

Experimental study of the form of "hot" steel particles on the ignition characteristics of liquid fuels

Science.gov (United States)

Zakharevich, Arkadiy V.

2015-01-01

The results of an experimental study of laws governing the ignition of liquid propellants (kerosene, diesel fuel and petroleum residue) by the single spherical steel particle heated to high temperatures are presented. Is carried out the comparison of the ignition delay times of the investigated flammable substances by the particles in the sphere and disk forms. It is established that the particle shape does not exert a substantial influence on the ignition process characteristics.

Genotoxic potential of diesel exhaust particles from the combustion of first- and second-generation biodiesel fuels-the FuelHealth project.

Science.gov (United States)

Kowalska, Magdalena; Wegierek-Ciuk, Aneta; Brzoska, Kamil; Wojewodzka, Maria; Meczynska-Wielgosz, Sylwia; Gromadzka-Ostrowska, Joanna; Mruk, Remigiusz; Øvrevik, Johan; Kruszewski, Marcin; Lankoff, Anna

2017-11-01

Epidemiological data indicate that exposure to diesel exhaust particles (DEPs) from traffic emissions is associated with higher risk of morbidity and mortality related to cardiovascular and pulmonary diseases, accelerated progression of atherosclerotic plaques, and possible lung cancer. While the impact of DEPs from combustion of fossil diesel fuel on human health has been extensively studied, current knowledge of DEPs from combustion of biofuels provides limited and inconsistent information about its mutagenicity and genotoxicity, as well as possible adverse health risks. The objective of the present work was to compare the genotoxicity of DEPs from combustion of two first-generation fuels, 7% fatty acid methyl esters (FAME) (B7) and 20% FAME (B20), and a second-generation 20% FAME/hydrotreated vegetable oil (SHB: synthetic hydrocarbon biofuel) fuel. Our results revealed that particulate engine emissions from each type of biodiesel fuel induced genotoxic effects in BEAS-2B and A549 cells, manifested as the increased levels of single-strand breaks, the increased frequencies of micronuclei, or the deregulated expression of genes involved in DNA damage signaling pathways. We also found that none of the tested DEPs showed the induction of oxidative DNA damage and the gamma-H2AX-detectable double-strand breaks. The most pronounced differences concerning the tested particles were observed for the induction of single-strand breaks, with the greatest genotoxicity being associated with the B7-derived DEPs. The differences in other effects between DEPs from the different biodiesel blend percentage and biodiesel feedstock were also observed, but the magnitude of these variations was limited.

The future of airborne sulfur-containing particles in the absence of fossil fuel sulfur dioxide emissions.

Science.gov (United States)

Perraud, Véronique; Horne, Jeremy R; Martinez, Andrew S; Kalinowski, Jaroslaw; Meinardi, Simone; Dawson, Matthew L; Wingen, Lisa M; Dabdub, Donald; Blake, Donald R; Gerber, R Benny; Finlayson-Pitts, Barbara J

2015-11-03

Sulfuric acid (H2SO4), formed from oxidation of sulfur dioxide (SO2) emitted during fossil fuel combustion, is a major precursor of new airborne particles, which have well-documented detrimental effects on health, air quality, and climate. Another precursor is methanesulfonic acid (MSA), produced simultaneously with SO2 during the atmospheric oxidation of organosulfur compounds (OSCs), such as dimethyl sulfide. In the present work, a multidisciplinary approach is used to examine how contributions of H2SO4 and MSA to particle formation will change in a large coastal urban area as anthropogenic fossil fuel emissions of SO2 decline. The 3-dimensional University of California Irvine-California Institute of Technology airshed model is used to compare atmospheric concentrations of gas phase MSA, H2SO4, and SO2 under current emissions of fossil fuel-associated SO2 and a best-case futuristic scenario with zero fossil fuel sulfur emissions. Model additions include results from (i) quantum chemical calculations that clarify the previously uncertain gas phase mechanism of formation of MSA and (ii) a combination of published and experimental estimates of OSC emissions, such as those from marine, agricultural, and urban processes, which include pet waste and human breath. Results show that in the zero anthropogenic SO2 emissions case, particle formation potential from H2SO4 will drop by about two orders of magnitude compared with the current situation. However, particles will continue to be generated from the oxidation of natural and anthropogenic sources of OSCs, with contributions from MSA and H2SO4 of a similar order of magnitude. This could be particularly important in agricultural areas where there are significant sources of OSCs.

Irradiation performance of coated fuel particles with fission product retaining kernel additives

International Nuclear Information System (INIS)

Foerthmann, R.

1979-10-01

The four irradiation experiments FRJ2-P17, FRJ2-P18, FRJ2-P19, and FRJ2-P20 for testing the efficiency of fission product-retaining kernel additives in coated fuel particles are described. The evaluation of the obtained experimental data led to the following results: - zirconia and alumina kernel additives are not suitable for an effective fission product retention in oxide fuel kernels, - alumina-silica kernel additives reduce the in-pile release of Sr 90 and Ba 140 from BISO-coated particles at temperatures of about 1200 0 C by two orders of magnitude, and the Cs release from kernels by one order of magnitude, - effective transport coefficients including all parameters which contribute to kernel release are given for (Th,U)O 2 mixed oxide kernels and low enriched UO 2 kernels containing 5 wt.% alumina-silica additives: 10g sub(K)/cm 2 s -1 = - 36 028/T + 6,261 (Sr 90), 10g Dsub(K)/cm 2 c -2 = - 29 646/T + 5,826 (Cs 134/137), alumina-silica kernel additives are ineffective for retaining Ag 110 m in coated particles. However, also an intact SiC-interlayer was found not to be effective at temperatures above 1200 0 C, - the penetration of the buffer layer by fission product containing eutectic additive melt during irradiation can be avoided by using additives which consist of alumina and mullite without an excess of silica, - annealing of LASER-failed irradiated particles and the irradiation test FRJ12-P20 indicate that the efficiency of alumina-silica kernel additives is not altered if the coating becomes defect. (orig.) [de

The compatibility of stainless steels with particles and powders of uranium carbide and low-sulphur UCS fuels

International Nuclear Information System (INIS)

Venter, S.

1978-05-01

Slightly hyperstoichiometric (U,Pu)C is a potential nuclear fuel for fast breeder reactors. The excess carbon above the stoichiometric amount results in a higher carbon activity in the fuel, and carbon is transferred to the stainless steel cladding, resulting in embrittlement of the cladding. It is with this problem of carbon transfer from the fuel to the cladding that this thesis is concerned. For practical reasons, UC and not (U,Pu)C was used as the fuel. The theory of decarburisation of carbide fuel and the carburisation of stainless steel, the facilities constructed for the project at the Atomic Energy Board, and the experimental techniques used, including preparation of the fuels, are discussed. The effect of a number of variables of uranium carbide fuel on its compatibility behaviour with stainless steels was investigated, as well as the effect om microstructure and type of stainless steel (304, 304 L and 316) on the rate of carburisation. These studies can be briefly summarised under the following headings: powder-particle size; surface oxidation of uranium carbide; preparation temperature of uranium carbide; low sulfur UCS fuels; uranium sulfide and the microstructure and type of steel. The author concludes that: the effect of surface oxidation and particle size must be taken into account when evaluating out-of-pile tests; the possible effects of surface oxidation must be taken into account when considering vibro-compacted carbide fuels; there is no advantage in replacing a fraction of the carbon atoms by sulphur atoms in slightly hyperstoichiometric carbide fuels, and the type and thermo-mechanical treatment of the stainless steel used as cladding material in a fuel pin is not important as far as the rate of carburisation by the fuel is concerned

Solubility of hot fuel particles from Chernobyl--influencing parameters for individual radiation dose calculations.

Science.gov (United States)

Garger, Evgenii K; Meisenberg, Oliver; Odintsov, Oleksiy; Shynkarenko, Viktor; Tschiersch, Jochen

2013-10-15

Nuclear fuel particles of Chernobyl origin are carriers of increased radioactivity (hot particles) and are still present in the atmosphere of the Chernobyl exclusion zone. Workers in the zone may inhale these particles, which makes assessment necessary. The residence time in the lungs and the transfer in the blood of the inhaled radionuclides are crucial for inhalation dose assessment. Therefore, the dissolution of several kinds of nuclear fuel particles from air filters sampled in the Chernobyl exclusion zone was studied. For this purpose filter fragments with hot particles were submersed in simulated lung fluids (SLFs). The activities of the radionuclides (137)Cs, (90)Sr, (239+240)Pu and (241)Am were measured in the SLF and in the residuum of the fragments by radiometric methods after chemical treatment. Soluble fractions as well as dissolution rates of the nuclides were determined. The influence of the genesis of the hot particles, represented by the (137)Cs/(239+240)Pu ratio, on the availability of (137)Cs was demonstrated, whereas the dissolution of (90)Sr, (239+240)Pu and (241)Am proved to be independent of genesis. No difference in the dissolution of (137)Cs and (239+240)Pu was observed for the two applied types of SLF. Increased solubility was found for smaller hot particles. A two-component exponential model was used to describe the dissolution of the nuclides as a function of time. The results were applied for determining individual inhalation dose coefficients for the workers at the Chernobyl construction site. Greater dose coefficients for the respiratory tract and smaller coefficients for the other organs were calculated (compared to ICRP default values). The effective doses were in general lower for the considered radionuclides, for (241)Am even by one order of magnitude. © 2013 Elsevier B.V. All rights reserved.

Device for the separation of spherically shaped fuel or breeding material particles for nuclear reactors

International Nuclear Information System (INIS)

Gyarmati, E.; Muenzer, R.

1974-01-01

Spherical fuel or blanket material particles are graded by diameter. The particles, which are present in a loose pebble bed, are singulized by means of a drum and by pneumatic suction. Next they pass through a drop section past an optical barrier which generates pulses corresponding to the number of particles. The particles then run through an eccentric wheel. This generates an electric voltage across a potentiometer which corresponds to the size of the particles. The slider of the potentiometer is connected with the axle of the eccentric wheel whose distance to the wall of the drop canal varies between the largest and the smallest possible diameters of the particles over half a revolution. Another barrier downstream of the eccentric wheel causes the particles to be graded in different containers in accordance with their diameters determined in this way. (DG) [de

Irradiation behavior of the interaction product of U-Mo fuel particle dispersion in an Al matrix

Energy Technology Data Exchange (ETDEWEB)

Kim, Yeon Soo, E-mail: yskim@anl.gov [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Hofman, G.L. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

2012-06-15

Highlights: Black-Right-Pointing-Pointer We in-pile tested U-Mo dispersion in Al matrix. Black-Right-Pointing-Pointer We observed interaction layer growth between U-Mo and Al and pore formation there. Black-Right-Pointing-Pointer Pores degrades thermal conductivity and structural integrity of the fueled zone. Black-Right-Pointing-Pointer The amorphous behavior of interaction layers is thought to be the main reason for unstable large pore growth. Black-Right-Pointing-Pointer A mechanism for pore formation and possible remedy to prevent it are proposed. - Abstract: Irradiation performance of U-Mo fuel particles dispersed in Al matrix is stable in terms of fuel swelling and is suitable for the conversion of research and test reactors from highly enriched uranium (HEU) to low enriched uranium (LEU). However, tests of the fuel at high temperatures and high burnups revealed obstacles caused by the interaction layers forming between the fuel particle and matrix. In some cases, fission gas filled pores grow and interconnect in the interdiffusion layer resulting in fuel plate failure. Postirradiation observations are made to examine the behavior of the interdiffusion layers. The interdiffusion layers show a fluid-like behavior characteristic of amorphous materials. In the amorphous interdiffusion layers, fission gas diffusivity is high and the material viscosity is low so that the fission gas pores readily form and grow. Based on the observations, a pore formation mechanism is proposed and potential remedies to suppress the pore growth are also introduced.

Quantum behaved Particle Swarm Optimization with Differential Mutation operator applied to WWER-1000 in-core fuel management optimization

International Nuclear Information System (INIS)

Jamalipour, Mostafa; Sayareh, Reza; Gharib, Morteza; Khoshahval, Farrokh; Karimi, Mahmood Reza

2013-01-01

Highlights: ► A new method called QPSO-DM is applied to BNPP in-core fuel management optimization. ► It is found that QPSO-DM performs better than PSO and QPSO. ► This method provides a permissible arrangement for optimum loading pattern. - Abstract: This paper presents a new method using Quantum Particle Swarm Optimization with Differential Mutation operator (QPSO-DM) for optimizing WWER-1000 core fuel management. Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) have shown good performance on in-core fuel management optimization (ICFMO). The objective of this paper is to show that QPSO-DM performs very well and is comparable to PSO and Quantum Particle Swarm Optimization (QPSO). Most of the strategies for ICFMO are based on maximizing multiplication factor (k eff ) to increase cycle length and minimizing power peaking factor (P q ) in order to improve fuel integrity. PSO, QPSO and QPSO-DM have been implemented to fulfill these requirements for the first operating cycle of WWER-1000 Bushehr Nuclear Power Plant (BNPP). The results show that QPSO-DM performs better than the others. A program has been written in MATLAB to map PSO, QPSO and QPSO-DM for loading pattern optimization. WIMS and CITATION have been used to simulate reactor core for neutronic calculations

Improvement of the homogeneity of atomized particles dispersed in high uranium density research reactor fuels

International Nuclear Information System (INIS)

Kim, Chang-Kyu; Kim, Ki-Hwan; Park, Jong-Man; Lee, Yoon-Sang; Lee, Don-Bae; Sohn, Woong-Hee; Hong, Soon-Hyung

1998-01-01

A study on improving the homogeneous dispersion of atomized spherical particles in fuel meats has been performed in connection with the development of high uranium density fuel. In comparing various mixing methods, the better homogeneity of the mixture could be obtained as in order of Spex mill, V-shape tumbler mixer, and off-axis rotating drum mixer. The Spex mill mixer required some laborious work because of its small capacity per batch. Trough optimizing the rotating speed parameter for the V-shape tumbler mixer, almost the same homogeneity as with the Spex mill could be obtained. The homogeneity of the extruded fuel meats appeared to improve through extrusion. All extruded fuel meats with U 3 Si powder of 50-volume % had fairly smooth surfaces. The homogeneity of fuel meats by V-shaped tumbler mixer revealed to be fairly good on micrographs. (author)

International R and D project on development of coated particle fuel for innovative reactors

International Nuclear Information System (INIS)

Kendall, J.M.

2001-01-01

The paper presents an outline for an international collaborative project of coated particle fuel development for innovative reactors. Specific issues include identification of R and D needs and the Member State facilities for meeting the needs followed by development and demonstration of technology. (author)

Steady- and transient-state analysis of fully ceramic microencapsulated fuel with randomly dispersed tristructural isotropic particles via two-temperature homogenized model-I: Theory and method

International Nuclear Information System (INIS)

Lee, Yoon Hee; Cho, Bum Hee; Cho, Nam Zin

2016-01-01

As a type of accident-tolerant fuel, fully ceramic microencapsulated (FCM) fuel was proposed after the Fukushima accident in Japan. The FCM fuel consists of tristructural isotropic particles randomly dispersed in a silicon carbide (SiC) matrix. For a fuel element with such high heterogeneity, we have proposed a two-temperature homogenized model using the particle transport Monte Carlo method for the heat conduction problem. This model distinguishes between fuel-kernel and SiC matrix temperatures. Moreover, the obtained temperature profiles are more realistic than those of other models. In Part I of the paper, homogenized parameters for the FCM fuel in which tristructural isotropic particles are randomly dispersed in the fine lattice stochastic structure are obtained by (1) matching steady-state analytic solutions of the model with the results of particle transport Monte Carlo method for heat conduction problems, and (2) preserving total enthalpies in fuel kernels and SiC matrix. The homogenized parameters have two desirable properties: (1) they are insensitive to boundary conditions such as coolant bulk temperatures and thickness of cladding, and (2) they are independent of operating power density. By performing the Monte Carlo calculations with the temperature-dependent thermal properties of the constituent materials of the FCM fuel, temperature-dependent homogenized parameters are obtained

Development of Improved Models and Designs for Coated-Particle Gas Reactor Fuels -- Final Report under the International Nuclear Energy Research Initiative (I-NERI)

Energy Technology Data Exchange (ETDEWEB)

Petti, David [Idaho National Lab. (INL), Idaho Falls, ID (United States). Idaho National Engineering and Environmental Lab. (INEEL); Martin, Philippe [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Phelip, Mayeul [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Ballinger, Ronald [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2004-12-01

The objective of this INERI project was to develop improved fuel behavior models for gas reactor coated-particle fuels and to explore improved coated-particle fuel designs that could be used reliably at very high burnups and potentially in gas-cooled fast reactors. Project participants included the Idaho National Engineering Laboratory (INEEL), Centre Étude Atomique (CEA), and the Massachusetts Institute of Technology (MIT). To accomplish the project objectives, work was organized into five tasks.

On gas and particle radiation in pulverized fuel combustion furnaces

DEFF Research Database (Denmark)

Yin, Chungen

2015-01-01

Radiation is the principal mode of heat transfer in a combustor. This paper presents a refined weighted sum of gray gases model for computational fluid dynamics modelling of conventional air-fuel combustion, which has greater accuracy and completeness than the existing gaseous radiative property...... models. This paper also presents new conversion-dependent models for particle emissivity and scattering factor, instead of various constant values in literature. The impacts of the refined or new models are demonstrated via computational fluid dynamics simulation of a pulverized coal-fired utility boiler...

[Particle emission characteristics of diesel bus fueled with bio-diesel].

Science.gov (United States)

Lou, Di-Ming; Chen, Feng; Hu, Zhi-Yuan; Tan, Pi-Qiang; Hu, Wei

2013-10-01

With the use of the Engine Exhaust Particle Sizer (EEPS), a study on the characteristics of particle emissions was carried out on a China-IV diesel bus fueled with blends of 5% , 10% , 20% , 50% bio-diesel transformed from restaurant waste oil and China-IV diesel (marked separately by BD5, BD10, BD20, BD50), pure bio-diesel (BD100) and pure diesel (BD0). The results indicated that particulate number (PN) and mass (PM) emissions of bio-diesel blends increased with the increase in bus speed and acceleration; with increasing bio-diesel content, particulate emissions displayed a relevant declining trend. In different speed ranges, the size distribution of particulate number emissions (PNSD) was bimodal; in different acceleration ranges, PNSD showed a gradual transition from bimodal shape to unimodal when bus operation was switched from decelerating to accelerating status. Bio-diesel blends with higher mixture ratios showed significant reduction in PN emissions for accumulated modes, and the particulate number emission peaks moved towards smaller sizes; but little change was obtained in PN emissions for nuclei modes; reduction also occurred in particle geometric diameter (Dg).

Local atomic structure of Pd and Ag in the SiC containment layer of TRISO fuel particles fissioned to 20% burn-up

Science.gov (United States)

Seibert, Rachel L.; Terrani, Kurt A.; Velázquez, Daniel; Hunn, John D.; Baldwin, Charles A.; Montgomery, Fred C.; Terry, Jeff

2018-03-01

The structure and speciation of fission products within the SiC barrier layer of tristructural-isotropic (TRISO) fuel particles irradiated to 19.6% fissions per initial metal atom (FIMA) burnup in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) was investigated. As-irradiated fuel particles, as well as those subjected to simulated accident scenarios, were examined. The TRISO particles were characterized using synchrotron X-ray absorption fine-structure spectroscopy (XAFS) at the Materials Research Collaborative Access Team (MRCAT) beamline at the Advanced Photon Source. The TRISO particles were produced at Oak Ridge National Laboratory under the Advanced Gas Reactor Fuel Development and Qualification Program and sent to the ATR for irradiation. XAFS measurements on the palladium and silver K-edges were collected using the MRCAT undulator beamline. Analysis of the Pd edge indicated the formation of palladium silicides of the form PdxSi (2 ≤ x ≤ 3). In contrast, Ag was found to be metallic within the SiC shell safety tested to 1700 °C. To the best of our knowledge, this is the first result demonstrating metallic bonding of silver from fissioned samples. Knowledge of these reaction pathways will allow for better simulations of radionuclide transport in the various coating layers of TRISO fuels for next generation nuclear reactors. They may also suggest different ways to modify TRISO particles to improve their fuel performance and to mitigate potential fission product release under both normal operation and accident conditions.

Application of particle swarm optimization in gas turbine engine fuel controller gain tuning

Science.gov (United States)

Montazeri-Gh, M.; Jafari, S.; Ilkhani, M. R.

2012-02-01

This article presents the application of particle swarm optimization (PSO) for gain tuning of the gas turbine engine (GTE) fuel controller. For this purpose, the structure of a fuel controller is firstly designed based on the GTE control requirements and constraints. The controller gains are then tuned by PSO where the tuning process is formulated as an engineering optimization problem. In this study, the response time during engine acceleration and deceleration as well as the engine fuel consumption are considered as the objective functions. A computer simulation is also developed to evaluate the objective values for a single spool GTE. The GTE model employed for the simulation is a Wiener model, the parameters of which are extracted from experimental tests. In addition, the effect of neighbour acceleration on PSO results is studied. The results show that the neighbour acceleration factor has a considerable effect on the convergence rate of the PSO process. The PSO results are also compared with the results obtained through a genetic algorithm (GA) to show the relative merits of PSO. Moreover, the PSO results are compared with the results obtained from the dynamic programming (DP) method in order to illustrate the ability of proposed method in finding the global optimal solution. Furthermore, the objective function is also defined in multi-objective manner and the multi-objective particle swarm optimization (MOPSO) is applied to find the Pareto-front for the problem. Finally, the results obtained from the simulation of the optimized controller confirm the effectiveness of the proposed approach to design an optimal fuel controller resulting in an improved GTE performance as well as protection against the physical limitations.

Experimental study of the form of “hot” steel particles on the ignition characteristics of liquid fuels

Directory of Open Access Journals (Sweden)

Zakharevich Arkadiy V.

2015-01-01

Full Text Available The results of an experimental study of laws governing the ignition of liquid propellants (kerosene, diesel fuel and petroleum residue by the single spherical steel particle heated to high temperatures are presented. Is carried out the comparison of the ignition delay times of the investigated flammable substances by the particles in the sphere and disk forms. It is established that the particle shape does not exert a substantial influence on the ignition process characteristics.

A study on properties-performances of coated particle fuel and on-line DB establishment

International Nuclear Information System (INIS)

Kim, Yong Soo; Lee, Hyo Cheol; Jang, Jeong Nam; Kwon, Seok Hwan

2007-03-01

Recently national project for HTGR for hydrogen production has been kicked off. However, For the successful development of the high temperature gas cooled reactor high temperature and burn-up dependent properties of the reactor materials are essentially and crucially required. Therefore, it was proposed to build up the materials properties and fuel performance data base. In this study, a phase - 1 properties and performance DB for coated particle fuel was developed. This database report consists two sections: materials properties and fuel performance. The materials properties has three parts: kernel materials, carbide coating materials, and fuel elements and graphite matrix. UO2 and UCO belong to kernel materials while PyC, SiC, and ZrC comprises the coating materials section. Thermal, mechanical and physical properties data of these materials were collected, reviewed, and summarized. Additionally, the property change induced by manufacture process and irradiation were reviewed. Fuel performance data were also collected, reviewed, and analyzed based on the key phenomena and failure mechanism, These performance data are divided into two: normal and accident. All of these data will be accessible in the pc based stand-alone system. These results will be directly used for HTGR fuel design and fabrication and preliminary fuel performance analysis under irradiation

Steady- and Transient-State Analyses of Fully Ceramic Microencapsulated Fuel with Randomly Dispersed Tristructural Isotropic Particles via Two-Temperature Homogenized Model—I: Theory and Method

Directory of Open Access Journals (Sweden)

Yoonhee Lee

2016-06-01

Full Text Available As a type of accident-tolerant fuel, fully ceramic microencapsulated (FCM fuel was proposed after the Fukushima accident in Japan. The FCM fuel consists of tristructural isotropic particles randomly dispersed in a silicon carbide (SiC matrix. For a fuel element with such high heterogeneity, we have proposed a two-temperature homogenized model using the particle transport Monte Carlo method for the heat conduction problem. This model distinguishes between fuel-kernel and SiC matrix temperatures. Moreover, the obtained temperature profiles are more realistic than those of other models. In Part I of the paper, homogenized parameters for the FCM fuel in which tristructural isotropic particles are randomly dispersed in the fine lattice stochastic structure are obtained by (1 matching steady-state analytic solutions of the model with the results of particle transport Monte Carlo method for heat conduction problems, and (2 preserving total enthalpies in fuel kernels and SiC matrix. The homogenized parameters have two desirable properties: (1 they are insensitive to boundary conditions such as coolant bulk temperatures and thickness of cladding, and (2 they are independent of operating power density. By performing the Monte Carlo calculations with the temperature-dependent thermal properties of the constituent materials of the FCM fuel, temperature-dependent homogenized parameters are obtained.

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

Mass spectrometric determination of gases in individual coated HTR fuel particles. I

International Nuclear Information System (INIS)

Strigl, A.; Bildstein, H.

1977-01-01

A method is described which allows the simultaneous determination of fission and reaction gases in individual coated particles at temperatures up to 2 000 0 C. The particles are heated under high-vacuum in a micro resistance-furnace up to the desired temperature. After preselected times the particles are crushed by action of a pneumatic cylinder. The gases liberated are fed into a quadrupole analyzer where they are analyzed in a dynamic mode. A peak selector allows the simultaneous measurement of up to four gases. The method is used routinely for the determination of fission gases (Kr and Xe) and of carbon monoxide which is formed as a reaction gas from oxide fuel. Precision and accuracy are in the order of a few percent. Detection limits for routine measurements are about 10 -7 cm 3 (STP) for Kr and Xe and 2x10 -5 cm 3 (STP) for CO but can be lowered by special techniques. (Auth.)

In situ ceramic layer growth on coated fuel particles dispersed in a zirconium metal matrix

Science.gov (United States)

Terrani, K. A.; Silva, C. M.; Kiggans, J. O.; Cai, Z.; Shin, D.; Snead, L. L.

2013-06-01

The extent and nature of the chemical interaction between the outermost coating layer of coated fuel particles embedded in zirconium metal during fabrication of metal matrix microencapsulated fuels were examined. Various particles with outermost coating layers of pyrocarbon, SiC, and ZrC have been investigated in this study. ZrC-Zr interaction was the least substantial, while the PyC-Zr reaction can be exploited to produce a ZrC layer at the interface in an in situ manner. The thickness of the ZrC layer in the latter case can be controlled by adjusting the time and temperature during processing. The kinetics of ZrC layer growth is significantly faster from what is predicted using literature carbon diffusivity data in ZrC. SiC-Zr interaction is more complex and results in formation of various chemical phases in a layered aggregate morphology at the interface.

The role of fission products (noble metal particles) in spent fuel corrosion process in a failed container

Energy Technology Data Exchange (ETDEWEB)

Wu, L., E-mail: lwu59@uwo.ca [Univ. of Western Ontario, Dept. of Chemistry, London, Ontario (Canada); Shoesmith, D.W. [Univ. of Western Ontario, Dept. of Chemistry, London, Ontario (Canada); Univ. of Western Ontario, Surface Science Western, London, Ontario (Canada)

2013-07-01

The corrosion/dissolution of simulated spent fuel has been studied electrochemically. Fission products within the UO{sub 2} matrix are found to have significant effect on the anodic dissolution behaviour of the fuel. It is observed that H{sub 2}O{sub 2}oxidation is accelerated on the surfaces of doped noble metal (ε) particles existing in the fuel matrix. It is concluded that H{sub 2}O{sub 2} decomposition rather than UO{sub 2} corrosion should be the dominant reaction under high H{sub 2}O{sub 2} concentrations. (author)

Experimental investigation of particle emissions under different EGR ratios on a diesel engine fueled by blends of diesel/gasoline/n-butanol

International Nuclear Information System (INIS)

Huang, Haozhong; Liu, Qingsheng; Wang, Qingxin; Zhou, Chengzhong; Mo, Chunlan; Wang, Xueqiang

2016-01-01

Highlights: • The effects of EGR and blend fuels on particulate emission were studied in CI engine. • EGR ⩽ 20%, gasoline or n-butanol increases total particulate number concentration. • EGR ⩾ 30%, gasoline or n-butanol reduces total particulate number concentration. • As EGR ratio increased, the particulate mass concentrations of four fuels increased. • Gasoline or n-butanol increases the ratio of sub-25 nm particles number concentration. - Abstract: The particle emission characteristics of a high-pressure common-rail engine under different EGR conditions were investigated, using pure diesel (D100), diesel/gasoline (with a volume ratio of 70:30, D70G30), diesel/n-butanol (with a volume ratio of 70:30, D70B30) and diesel/gasoline/n-butanol (with a volume ratio of 70:15:15, D70G15B15) for combustion. Our results show that, with increasing EGR ratios, the in-cylinder pressure peak decreases and the heat release is delayed for the combustion of each fuel. At an EGR ratio of 30%, the combustion pressure peaks of D70G30, D70B30, D70G15B15 and D100 have similar values; with an EGR ratio of 40%, the combustion pressure peaks and release rate peaks of D70G30 and D70G15B15 are both lower with respect to D100. For small and medium EGR ratios (⩽20%), after the addition of gasoline and/or n-butanol to the fuel, the total particle number concentration (TPNC) increases, while both the soot emissions and the average geometric size of particles decrease. At large EGR ratios (30% and 40%), the TPNC of D70B30, D70G15B15 and D70G20 compared to D100 are reduced by a maximum amount of 74.7%, 66.7% and 28.6%, respectively. As the EGR ratio increases, the total particle mass concentration increases gradually for all four fuels. Blending gasoline or/and n-butanol into diesel induces an increase in the number concentration of sub-25 nm particles (PN25) which may be harmful in terms of health. However, the PN25 decreases with increasing the EGR ratio for all the tested fuels

HTGR Fuel performance basis

International Nuclear Information System (INIS)

Shamasundar, B.I.; Stansfield, O.M.; Jensen, D.D.

1982-05-01

The safety characteristics of the high-temperature gas-cooled reactor (HTGR) during normal and accident conditions are determined in part by HTGR fuel performance. During normal operation, less than 0.1% fuel failure occurs, primarily from defective particles. This low fuel failure fraction limits circulating activity to acceptable levels. During severe accidents, the radiological consequence is influenced by high-temperature fuel particle behavior. An empirical fuel failure model, supported by recent experimental data, is presented. The onset of significant fuel particle failure occurs at temperatures in excess of 1600 0 C, and complete fuel failure occurs at 2660 0 C. This indicates that the fuel is more retentive at higher temperatures than previously assumed. The more retentive nature of the fuel coupled with the high thermal capacitance of the core results in slow release of fission products from the core during severe accidents

Monte Carlo simulation of VHTR particle fuel with chord length sampling

International Nuclear Information System (INIS)

Ji, W.; Martin, W. R.

2007-01-01

The Very High Temperature Gas-Cooled Reactor (VHTR) poses a problem for neutronic analysis due to the double heterogeneity posed by the particle fuel and either the fuel compacts in the case of the prismatic block reactor or the fuel pebbles in the case of the pebble bed reactor. Direct Monte Carlo simulation has been used in recent years to analyze these VHTR configurations but is computationally challenged when space dependent phenomena are considered such as depletion or temperature feedback. As an alternative approach, we have considered chord length sampling to reduce the computational burden of the Monte Carlo simulation. We have improved on an existing method called 'limited chord length sampling' and have used it to analyze stochastic media representative of either pebble bed or prismatic VHTR fuel geometries. Based on the assumption that the PDF had an exponential form, a theoretical chord length distribution is derived and shown to be an excellent model for a wide range of packing fractions. This chord length PDF was then used to analyze a stochastic medium that was constructed using the RSA (Random Sequential Addition) algorithm and the results were compared to a benchmark Monte Carlo simulation of the actual stochastic geometry. The results are promising and suggest that the theoretical chord length PDF can be used instead of a full Monte Carlo random walk simulation in the stochastic medium, saving orders of magnitude in computational time (and memory demand) to perform the simulation. (authors)

Mechanical Properties and Structures of Pyrolytic Carbon Coating Layer in HTR Coated Particle Fuel

International Nuclear Information System (INIS)

Lee, Young Woo; Kim, Young Min; Kim, Woong Ki; Cho, Moon Sung

2009-01-01

The TRISO(tri-isotropic)-coated fuel particle for a HTR(High Temperature gas-cooled Reactor) has a diameter of about 1 mm, composed of a nuclear fuel kernel and four different outer coating layers, consisting of a buffer PyC (pyrolytic carbon) layer, inner PyC layer, SiC layer, and outer PyC layer with different coating thicknesses following a specific fuel design. While the fuel kernel is a source for a heat generation by a nuclear fission of fissile uranium, each of the four coating layers acts as a different role in view of retaining the generated fission products and the other interactions during an in-reactor service. Among these coating layers, PyC properties are scarcely in agreement among various investigators and the dependency of their changes upon the deposition condition is comparatively large due to their additional anisotropic properties. Although a recent review work has contributed to an establishment of relationship between the material properties and QC measurements, the data on the mechanical properties and structural parameters of PyC coating layers remain still unclearly evaluated. A review work on dimensional changes of PyC by neutron irradiation was one of re-evaluative works recently attempted by the authors. In this work, an attempt was made to analyze and re-evaluate the existing data of the experimental results of the mechanical properties, i.e., Young's modulus and fracture stress, in relation with the coating conditions, density and the BAF (Bacon Anisotropy Factor), an important structural parameter, of PyC coating layers obtained from various experiments performed in the early periods of the HTR coated particle development

Detection of gas-permeable fuel particles for highl 7490 temperature gas-cooled reactors

International Nuclear Information System (INIS)

Thiele, B.A.; Stinton, D.P.; Costanzo, D.A.

1980-01-01

Fuel for High-Temperature Gas-Cooled Reactors (HTGR) consists of uranium oxide-carbide and thoria microspheres coated with layers of pyrolytic carbon and silicon carbide. The pyrolytic carbon coatings must be gas-tight to perform properly during irradiation. Therefore, particles must be carefully characterized to determine the number of defective particles (ie bare kernels, and cracked or permeable coatings). Although techniques are available to determine the number of bare kernels or cracked coatings, no reliable technique has been available to measure coating permeability. This work describes a technique recently developed to determine whether coatings for a batch of particles are gas-tight or permeable. Although most of this study was performed on Biso-coated particles, the technique applies equally well to Triso-coated particles. About 150 randomly selected Biso-particle batches were studied in this work. These batches were first subjected to an 18-hr chlorination at 15000C, and the volatile thorium tetrachloride released through cracked or very permeable coatings was measured versus chlorination time. Chlorinated batches were also radiographed to detect any thorium that had migrated from the kernel into the coatings. From this work a technique was developed to determine coating permeability. This consists of an 18-hr chlorination of multiple samples without measurement of the heavy metal released. Each batch is then radiographed and the heavy metal diffusion within each particle is examined so it can be determined if a particle batch is permeable, slightly permeable, or gas-tight. (author)

In-line monitoring of effluents from HTGR fuel particle preparation processes using a time-of-flight mass spectrometer

International Nuclear Information System (INIS)

Lee, D.A.; Costanzo, D.A.; Stinton, D.P.; Carpenter, J.A.; Rainey, W.T. Jr.; Canada, D.C.; Carter, J.A.

1976-08-01

The carbonization, conversion, and coating processes in the manufacture of HTGR fuel particles have been studied with the use of a time-of-flight mass spectrometer. Non-condensable effluents from these fluidized-bed processes have been monitored continuously from the beginning to the end of the process. The processes which have been monitored are these: uranium-loaded ion exchange resin carbonization, the carbothermic reduction of UO 2 to UC 2 , buffer and low temperature isotropic pyrocarbon coatings of fuel kernels, SiC coating of the kernels, and high-temperature particle annealing. Changes in concentrations of significant molecules with time and temperature have been useful in the interpretation of reaction mechanisms and optimization of process procedures

Particle swarm optimization of driving torque demand decision based on fuel economy for plug-in hybrid electric vehicle

International Nuclear Information System (INIS)

Shen, Peihong; Zhao, Zhiguo; Zhan, Xiaowen; Li, Jingwei

2017-01-01

In this paper, an energy management strategy based on logic threshold is proposed for a plug-in hybrid electric vehicle. The plug-in hybrid electric vehicle powertrain model is established using MATLAB/Simulink based on experimental tests of the power components, which is validated by the comparison with the verified simulation model which is built in the AVL Cruise. The influence of the driving torque demand decision on the fuel economy of plug-in hybrid electric vehicle is studied using a simulation. The optimization method for the driving torque demand decision, which refers to the relationship between the accelerator pedal opening and driving torque demand, from the perspective of fuel economy is formulated. The dynamically changing inertia weight particle swarm optimization is used to optimize the decision parameters. The simulation results show that the optimized driving torque demand decision can improve the PHEV fuel economy by 15.8% and 14.5% in the fuel economy test driving cycle of new European driving cycle and worldwide harmonized light vehicles test respectively, using the same rule-based energy management strategy. The proposed optimization method provides a theoretical guide for calibrating the parameters of driving torque demand decision to improve the fuel economy of the real plug-in hybrid electric vehicle. - Highlights: • The influence of the driving torque demand decision on the fuel economy is studied. • The optimization method for the driving torque demand decision is formulated. • An improved particle swarm optimization is utilized to optimize the parameters. • Fuel economy is improved by using the optimized driving torque demand decision.

Influence of process variables on permeability and anisotropy of Biso-coated HTGR fuel particles

International Nuclear Information System (INIS)

Stinton, D.P.; Lackey, W.J.; Thiele, B.A.

1977-11-01

The effect of several important process variables on the fraction of defective particles and anisotropy of the low-temperature isotropic (LTI) coating layer was determined for Biso-coated HTGR fuel particles. Process variables considered are deposition temperature, hydrocarbon type, diluent type, and percent diluent. The effect of several other variables such as coating rate and density that depend on the process variables were also considered in this analysis. The fraction of defective particles was controlled by the dependent variables coating rate and LTI density. Coating rate was also the variable controlling the anisotropy of the LTI layer. Diluent type and diluent concentration had only a small influence on the deposition rate of the LTI layer. High-quality particles in terms of anisotropy and permeability can be produced by use of a porous plate gas distributor if the coating rate is between 3 and 5 μm/min and the coating density is between about 1.75 and 1.95 g/cm 3

Particle size dependence of CO tolerance of anode PtRu catalysts for polymer electrolyte fuel cells

Science.gov (United States)

Yamanaka, Toshiro; Takeguchi, Tatsuya; Wang, Guoxiong; Muhamad, Ernee Noryana; Ueda, Wataru

An anode catalyst for a polymer electrolyte fuel cell must be CO-tolerant, that is, it must have the function of hydrogen oxidation in the presence of CO, because hydrogen fuel gas generated by the steam reforming process of natural gas contains a small amount of CO. In the present study, PtRu/C catalysts were prepared with control of the degree of Pt-Ru alloying and the size of PtRu particles. This control has become possible by a new method of heat treatment at the final step in the preparation of catalysts. The CO tolerances of PtRu/C catalysts with the same degree of Pt-Ru alloying and with different average sizes of PtRu particles were thus compared. Polarization curves were obtained with pure H 2 and CO/H 2 (CO concentrations of 500-2040 ppm). It was found that the CO tolerance of highly dispersed PtRu/C (high dispersion (HD)) with small PtRu particles was much higher than that of poorly dispersed PtRu/C (low dispersion (LD)) with large metal particles. The CO tolerance of PtRu/C (HD) was higher than that of any commercial PtRu/C. The high CO tolerance of PtRu/C (HD) is thought to be due to efficient concerted functions of Pt, Ru, and their alloy.

Application of the beta particles backscattering technique for determining the thickness of the cladding in nuclear fuels plate

International Nuclear Information System (INIS)

Koshimizu, S.; Ferreira, P.I.; Lima, L.F.C.P. de; Vieira, J.M.; Perez, H.E.B.

1984-01-01

A prototype of an instalation to measure thickness of cladding and core of nuclear fuels plate using the beta particles backscattering technique is constructed. The method and calibration system is described. The thickness measurements of the cladding and core were done in a natural uranium fuel plate developed at IPEN. The reliability of the method is confirmed by the metalographic measures analysis. (E.G.) [pt

Mixing large and small particles in a pilot scale rotary kiln

DEFF Research Database (Denmark)

Nielsen, Anders Rooma; Aniol, Rasmus Wochnik; Larsen, Morten Boberg

2011-01-01

The mixing of solid alternative fuel particles in cement raw materials was studied experimentally by visual observation in a pilot scale rotary kiln. Fuel particles were placed on top of the raw material bed prior to the experiment. The percentage of particles visible above the bed as a function...... of time was evaluated with the bed predominantly in the rolling bed mode. Experiments were conducted to investigate the effects of fuel particle size and shape, fuel particle density, rotary kiln fill degree and rotational speed. Large fuel particles and low-density fuel particles appeared more on top...... of the bed than smaller particles and high-density fuel particles. Fuel particle dimensions and sphericity were important parameters for the percentage of visible particles. Increasing bed fill degree and/or increasing rotational speed decreased the percentage of particles visible on top of the bed...

Prediction of the thermal behavior of a particle spherical fuel element using GITT

International Nuclear Information System (INIS)

Pessoa, C.V.; Oliveira, Claudio L. de; Jian, Su

2008-01-01

In this work, the transient and steady state heat conduction in a spherical fuel element of a pebble-bed high temperature were studied. This pebble element is composed by a particulate region with spherical inclusions, the fuel UO 2 particles, dispersed in a graphite matrix. A convective heat transfer by helium occurs on the outer surface of the fuel element. The two-energy equation model for the case of pure conduction was applied to this particulate spherical element, generating two macroscopic temperatures, respectively, of the inclusions and of the matrix. The transient analysis was carried out by using the Generalized Integral Transform Technique (GITT) that requires low computational efforts and allows a fast evaluation of the two macroscopic transient temperatures of the particulate region. The solution by GITT leads to a system of ordinary differential equations with the unknown transformed potentials. The mechanical properties (thermal conductivity and specific heat) of the materials were supposed not to depend on the temperature and to be uniform in each region. (author)

High-temperature deformation and processing maps of Zr-4 metal matrix with dispersed coated surrogate nuclear fuel particles

Science.gov (United States)

Chen, Jing; Liu, Huiqun; Zhang, Ruiqian; Li, Gang; Yi, Danqing; Lin, Gaoyong; Guo, Zhen; Liu, Shaoqiang

2018-06-01

High-temperature compression deformation of a Zr-4 metal matrix with dispersed coated surrogate nuclear fuel particles was investigated at 750 °C-950 °C with a strain rate of 0.01-1.0 s-1 and height reduction of 20%. Scanning electron microscopy was utilized to investigate the influence of the deformation conditions on the microstructure of the composite and damage to the coated surrogate fuel particles. The results indicated that the flow stress of the composite increased with increasing strain rate and decreasing temperature. The true stress-strain curves showed obvious serrated oscillation characteristics. There were stable deformation ranges at the initial deformation stage with low true strain at strain rate 0.01 s-1 for all measured temperatures. Additionally, the coating on the surface of the surrogate nuclear fuel particles was damaged when the Zr-4 matrix was deformed at conditions of high strain rate and low temperature. The deformation stability was obtained from the processing maps and microstructural characterization. The high-temperature deformation activation energy was 354.22, 407.68, and 433.81 kJ/mol at true strains of 0.02, 0.08, and 0.15, respectively. The optimum deformation parameters for the composite were 900-950 °C and 0.01 s-1. These results are expected to provide guidance for subsequent determination of possible hot working processes for this composite.

Plan of development of ZrC-TRISO coated fuel particle and construction of ZrC coater

Energy Technology Data Exchange (ETDEWEB)

Ueta, Shohei; Ino, Hiroichi; Sawa, Kazuhiro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Tobita, Tsutomu [Nuclear Engineering Company, Ltd., Tokai, Ibaraki (Japan); Takahashi, Masashi [Nuclear Fuel Industries, Ltd., Tokyo (Japan)

2002-11-01

In order to use coated fuel particle under higher temperature condition, more refractory coating material, which is more refractory than conventional silicon carbide (SiC), should be applied. Zirconium carbide (ZrC) is considered to be one of the promising materials, which is proposed as candidate for VHTR fuel material in GENERATION-IV, because of its intactness under high temperature of around 2000degC and its higher stability against kernel migration (amoeba effect) and fission product corrosion under normal operating condition. In order to develop ZrC coated particle for commercial use, research and development items were extracted based on review of the previous works. Research and development plan was determined. Based on the plan, a new ZrC coater of 100g batch size, which applies bromine process, was constructed. This report describes the review of precious works, extracted research and develop items and plan, and specifications of the ZrC coater. (author)

Droplet size measurement of diesel fuel spray particles using a planar laser-induced fluorescence method; Nijigen laser yuki keikoho wo mochiita diesel funmu ryushi no ryukei keisoku ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, N. [Isuzu Motors Ltd., Tokyo (Japan); Niimura, K. [Nissan Diesel Motor Co. Ltd., Saitama (Japan); Tsujimura, K.

1997-11-25

In this study, the planar laser-induced fluorescence (PLIF) technique was used to measure the mean size and size distribution of diesel spray particles. The fuel used was n-tridecane mixed with 1 wt% N, N, Nprime, Nprime-tetramethylparaphenyenediamine (TMPD). The light source used to excite the TMPD in the fuel was a secondary harmonic of a ruby laser-light sheet. A highly magnified image of the fluorescence from TMPD was taken by a 35 mm still camera with magnified optics, and the mean particle size and particle size distribution of the fuel spray were determined by processing the images of fuel particles printed on paper. First, the accuracy of this method was confirmed by comparison with results of Phase Doppler Anemometry for fuel spray of an air-assisted gasoline injector. Then, for the diesel spray, the effects of injection velocity, ambient pressure, geometric configuration of nozzle hole (i.e., nozzle hole diameter and nozzle hole L/D) and of measurement points on the fuel particle mean size and size distribution in a high-pressure vessel at atmospheric temperature were investigated. The results showed that the small size particles increase in number with increasing injection velocity. At higher injection velocity, seem to atomize more actively. With increasing ambient pressure, the mean particle size increases. A reduction in nozzle diameter resulted in no improvement of atomization in this study. Also, the mean particle size in the downstream region of the spray is larger than that in the upstream region of the spray. 16 refs., 19 figs., 3 tabs.

Durable fuel electrode

DEFF Research Database (Denmark)

2017-01-01

the composite. The invention also relates to the use of the composite as a fuel electrode, solid oxide fuel cell, and/or solid oxide electrolyser. The invention discloses a composite for an electrode, comprising a three-dimensional network of dispersed metal particles, stabilised zirconia particles and pores...

Nuclear Energy Research Initiative Project No. 02 103 Innovative Low Cost Approaches to Automating QA/QC of Fuel Particle Production Using On Line Nondestructive Methods for Higher Reliability Final Project Report

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Salahuddin; Batishko, Charles R.; Flake, Matthew; Good, Morris S.; Mathews, Royce; Morra, Marino; Panetta, Paul D.; Pardini, Allan F.; Sandness, Gerald A.; Tucker, Brian J.; Weier, Dennis R.; Hockey, Ronald L.; Gray, Joseph N.; Saurwein, John J.; Bond, Leonard J.; Lowden, Richard A.; Miller, James H.

2006-02-28

This Nuclear Energy Research Initiative (NERI) project was tasked with exploring, adapting, developing and demonstrating innovative nondestructive test methods to automate nuclear coated particle fuel inspection so as to provide the United States (US) with necessary improved and economical Quality Assurance and Control (QA/QC) that is needed for the fuels for several reactor concepts being proposed for both near term deployment [DOE NE & NERAC, 2001] and Generation IV nuclear systems. Replacing present day QA/QC methods, done manually and in many cases destructively, with higher speed automated nondestructive methods will make fuel production for advanced reactors economically feasible. For successful deployment of next generation reactors that employ particle fuels, or fuels in the form of pebbles based on particles, extremely large numbers of fuel particles will require inspection at throughput rates that do not significantly impact the proposed manufacturing processes. The focus of the project is nondestructive examination (NDE) technologies that can be automated for production speeds and make either: (I) On Process Measurements or (II) In Line Measurements. The inspection technologies selected will enable particle “quality” qualification as a particle or group of particles passes a sensor. A multiple attribute dependent signature will be measured and used for qualification or process control decisions. A primary task for achieving this objective is to establish standard signatures for both good/acceptable particles and the most problematic types of defects using several nondestructive methods.

Interaction between UO2 kernel and pyrocarbon coating in irradiated and unirradiated HTR fuel particles

International Nuclear Information System (INIS)

Drago, A.; Klersy, R.; Simoni, O.; Schrader, K.H.

1975-08-01

Experimental observations on unidirectional UO 2 kernel migration in TRISO type coated particle fuels are reported. An analysis of the experimental results on the basis of data and models from the literature is reported. The stoichiometric composition of the kernel is considered the main parameter that, associated with a temperature gradient, controls the unidirectional kernel migration

Aerosol feed direct methanol fuel cell

Science.gov (United States)

Kindler, Andrew (Inventor); Narayanan, Sekharipuram R. (Inventor); Valdez, Thomas I. (Inventor)

2002-01-01

Improvements to fuel cells include introduction of the fuel as an aerosol of liquid fuel droplets suspended in a gas. The particle size of the liquid fuel droplets may be controlled for optimal fuel cell performance by selection of different aerosol generators or by separating droplets based upon size using a particle size conditioner.

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

Method of making nuclear fuel bodies

International Nuclear Information System (INIS)

Davis, D.E.; Leary, D.F.

1977-01-01

A method of making nuclear fuel bodies is described comprising: providing particulate graphite having a particle size not greater than about 1500 microns; impregnating the graphite with a polymerizable organic resin in liquid form; treating the impregnated particles with a hot aqueous acid solution to pre-cure the impregnated resin and to remove excess resin from the surfaces of said graphite particles; heating the treated particles to polymerize the impregnant; blending the impregnated particles with particulate nuclear fuel; and forming a nuclear fuel body by joining the blend of particles into a cohesive mass using a carbonaceous binder

Nuclear fuel element

International Nuclear Information System (INIS)

Yamamoto, Seigoro.

1994-01-01

Ultrafine particles of a thermal neutron absorber showing ultraplasticity is dispersed in oxide ceramic fuels by more than 1% to 10% or lower. The ultrafine particles of the thermal neutron absorber showing ultrafine plasticity is selected from any one of ZrGd, HfEu, HfY, HfGd, ZrEu, and ZrY. The thermal neutron absorber is converted into ultrafine particles and solid-solubilized in a nuclear fuel pellet, so that the dispersion thereof into nuclear fuels is made uniform and an absorbing performance of the thermal neutrons is also made uniform. Moreover, the characteristics thereof, for example, physical properties such as expansion coefficient and thermal conductivity of the nuclear fuels are also improved. The neutron absorber, such as ZrGd or the like, can provide plasticity of nuclear fuels, if it is mixed into the nuclear fuels for showing the plasticity. The nuclear fuel pellets are deformed like an hour glass as burning, but, since the end portion thereof is deformed plastically within a range of a repulsive force of the cladding tube, there is no worry of damaging a portion of the cladding tube. (N.H.)

Nuclear fuel element

International Nuclear Information System (INIS)

Penrose, R.T.; Thompson, J.R.

1976-01-01

A method of protecting the cladding of a nuclear fuel element from internal attack and a nuclear fuel element for use in the core of a nuclear reactor are disclosed. The nuclear fuel element has disposed therein an additive of a barium-containing material and the barium-containing material collects reactive gases through chemical reaction or adsorption at temperatures ranging from room temperature up to fuel element plenum temperatures. The additive is located in the plenum of the fuel element and preferably in the form of particles in a hollow container having a multiplicity of gas permeable openings in one portion of the container with the openings being of a size smaller than the size of the particles. The openings permit gases and liquids entering the plenum to contact the particles. The additive is comprised of elemental barium or a barium alloy containing one or more metals in addition to barium such as aluminum, zirconium, nickel, titanium and combinations thereof. 6 claims, 3 drawing figures

Tracking of fuel particles after pin failure in nominal, loss-of-flow and shutdown conditions in the MYRRHA reactor

Energy Technology Data Exchange (ETDEWEB)

Buckingham, Sophia; Planquart, Philippe [von Karman Institute, Chaussée de Waterloo 72, B-1640 Rhode-St-Genèse (Belgium); Van Tichelen, Katrien [SCK- CEN, Boeretang 200, 2400 Mol (Belgium)

2017-02-15

Highlights: • Quantification of the design and safety of the MYRRHA reactor in the event of a pin failure. • Simulation of different accident scenarios in both forced and natural convection regime. • The accumulation areas at the free-surface in case of the least dense particles depend on the flow regime. • The densest particles form an important deposit at the bottom of the vessel. • Further study of the risk of core blockage requires a detailed model of the core. - Abstract: This work on fuel dispersion aims at quantifying the design and safety of the MYRRHA nuclear reactor. A number of accidents leading to the release of a secondary phase into the primary coolant loop are investigated. Among these scenarios, an incident leading to the failure of one or more of the fuel pins is simulated while the reactor is operating in nominal conditions, but also in natural convection regime either during accident transients such as loss-of-flow or during the normal shut-down of the reactor. Two single-phase CFD models of the MYRRHA reactor are constructed in ANSYS Fluent to represent the reactor in nominal and natural convection conditions. An Euler–Lagrange approach with one-way coupling is used for the flow and particle tracking. Firstly, a steady state RANS solution is obtained for each of the three conditions. Secondly, the particles are released downstream from the core outlet and particle distributions are provided over the coolant circuit. Their size and density are defined such that test cases represent potential extremes that may occur. Analysis of the results highlights different particle behaviors, depending essentially on gravity forces and kinematic effects. Statistical distributions highlight potential accumulation regions that may form at the free-surfaces, on top of the upper diaphragm plate or at the bottom of the vessel. These results help to localize regions of fuel accumulation in order to provide insight for development of strategies for

Irradiation test OF-2: high-temperature irradiation behavior of LASL-made fuel rods and LASL-made coated particles

International Nuclear Information System (INIS)

Wagner, P.; Reiswig, R.D.; Hollabaugh, C.M.; White, R.W.; O'Rourke, J.A.; Davidson, K.V.; Schell, D.H.

1977-10-01

Three LASL-made, substoichiometric ZrC-coated particles with inert kernels, and two high-density molded graphite fuel rods that contained LASL-made, ZrC-coated fissile particles were irradiated in the Oak Ridge Research Reactor test OF-2. The severest test conditions were 8.36 x 10 21 nvt (E greater than 0.18 MeV) at 1350 0 C. The graphite matrix showed no effect of the irradiation. There was no interaction between the matrix and any of the particle coats. The loose ZrC coated particles with inert kernels showed no irradiation effects. The graded ZrC-C coats on the fissile particles were cracked. It is postulated that the cracking is associated with the low LTI deposition rate and is not related to the ZrC

Analysis of Advanced Fuel Kernel Technology

International Nuclear Information System (INIS)

Oh, Seung Chul; Jeong, Kyung Chai; Kim, Yeon Ku; Kim, Young Min; Kim, Woong Ki; Lee, Young Woo; Cho, Moon Sung

2010-03-01

The reference fuel for prismatic reactor concepts is based on use of an LEU UCO TRISO fissile particle. This fuel form was selected in the early 1980s for large high-temperature gas-cooled reactor (HTGR) concepts using LEU, and the selection was reconfirmed for modular designs in the mid-1980s. Limited existing irradiation data on LEU UCO TRISO fuel indicate the need for a substantial improvement in performance with regard to in-pile gaseous fission product release. Existing accident testing data on LEU UCO TRISO fuel are extremely limited, but it is generally expected that performance would be similar to that of LEU UO 2 TRISO fuel if performance under irradiation were successfully improved. Initial HTGR fuel technology was based on carbide fuel forms. In the early 1980s, as HTGR technology was transitioning from high-enriched uranium (HEU) fuel to LEU fuel. An initial effort focused on LEU prismatic design for large HTGRs resulted in the selection of UCO kernels for the fissile particles and thorium oxide (ThO 2 ) for the fertile particles. The primary reason for selection of the UCO kernel over UO 2 was reduced CO pressure, allowing higher burnup for equivalent coating thicknesses and reduced potential for kernel migration, an important failure mechanism in earlier fuels. A subsequent assessment in the mid-1980s considering modular HTGR concepts again reached agreement on UCO for the fissile particle for a prismatic design. In the early 1990s, plant cost-reduction studies led to a decision to change the fertile material from thorium to natural uranium, primarily because of a lower long-term decay heat level for the natural uranium fissile particles. Ongoing economic optimization in combination with anticipated capabilities of the UCO particles resulted in peak fissile particle burnup projection of 26% FIMA in steam cycle and gas turbine concepts

Apparatus for blending small particles

International Nuclear Information System (INIS)

Bradley, R.A.; Reese, C.R.; Sease, J.D.

1975-01-01

An apparatus is described for blending small particles and uniformly loading the blended particles in a receptacle. Measured volumes of various particles are simultaneously fed into a funnel to accomplish radial blending and then directed onto the apex of a conical splitter which collects the blended particles in a multiplicity of equal subvolumes. Thereafter the apparatus sequentially discharges the subvolumes for loading in a receptacle. A system for blending nuclear fuel particles and loading them into fuel rod molds is described in a preferred embodiment

Automatic fuel lattice design in a boiling water reactor using a particle swarm optimization algorithm and local search

International Nuclear Information System (INIS)

Lin Chaung; Lin, Tung-Hsien

2012-01-01

Highlights: ► The automatic procedure was developed to design the radial enrichment and gadolinia (Gd) distribution of fuel lattice. ► The method is based on a particle swarm optimization algorithm and local search. ► The design goal were to achieve the minimum local peaking factor. ► The number of fuel pins with Gd and Gd concentration are fixed to reduce search complexity. ► In this study, three axial sections are design and lattice performance is calculated using CASMO-4. - Abstract: The axial section of fuel assembly in a boiling water reactor (BWR) consists of five or six different distributions; this requires a radial lattice design. In this study, an automatic procedure based on a particle swarm optimization (PSO) algorithm and local search was developed to design the radial enrichment and gadolinia (Gd) distribution of the fuel lattice. The design goals were to achieve the minimum local peaking factor (LPF), and to come as close as possible to the specified target average enrichment and target infinite multiplication factor (k ∞ ), in which the number of fuel pins with Gd and Gd concentration are fixed. In this study, three axial sections are designed, and lattice performance is calculated using CASMO-4. Finally, the neutron cross section library of the designed lattice is established by CMSLINK; the core status during depletion, such as thermal limits, cold shutdown margin and cycle length, are then calculated using SIMULATE-3 in order to confirm that the lattice design satisfies the design requirements.

High Temperature Fuel Cladding Chemical Interactions Between TRIGA Fuels and 304 Stainless Steel

Energy Technology Data Exchange (ETDEWEB)

Perez, Emmanuel [Idaho National Lab. (INL), Idaho Falls, ID (United States); Keiser, Jr., Dennis D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Forsmann, Bryan [Boise State Univ., ID (United States); Janney, Dawn E. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Henley, Jody [Idaho National Lab. (INL), Idaho Falls, ID (United States); Woolstenhulme, Eric C. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-02-01

High-temperature fuel-cladding chemical interactions (FCCI) between TRIGA (Training, Research, Isotopes, General Atomics) fuel elements and the 304 stainless steel (304SS) are of interest to develop an understanding of the fuel behavior during transient reactor scenarios. TRIGA fuels are composed of uranium (U) particles dispersed in a zirconium-hydride (Zr-H) matrix. In reactor, the fuel is encased in 304-stainless-steel (304SS) or Incoloy 800 clad tubes. At high temperatures, the fuel can readily interact with the cladding, resulting in FCCI. A number of FCCI can take place in this system. Interactions can be expected between the cladding and the Zr-H matrix, and/or between the cladding and the U-particles. Other interactions may be expected between the Zr-H matrix and the U-particles. Furthermore, the fuel contains erbium-oxide (Er-O) additions. Interactions can also be expected between the Er-O, the cladding, the Zr-H and the U-particles. The overall result is that very complex interactions may take place as a result of fuel and cladding exposures to high temperatures. This report discusses the characterization of the baseline fuel microstructure in the as-received state (prior to exposure to high temperature), characterization of the fuel after annealing at 950C for 24 hours and the results from diffusion couple experiments carries out at 1000C for 5 and 24 hours. Characterization was carried out via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with sample preparation via focused ion beam in situ-liftout-technique.

High Temperature Fuel Cladding Chemical Interactions Between TRIGA Fuels and 304 Stainless Steel

International Nuclear Information System (INIS)

Perez, Emmanuel; Keiser Jr, Dennis D.; Forsmann, Bryan; Janney, Dawn E.; Henley, Jody; Woolstenhulme, Eric C.

2016-01-01

High-temperature fuel-cladding chemical interactions (FCCI) between TRIGA (Training, Research, Isotopes, General Atomics) fuel elements and the 304 stainless steel (304SS) are of interest to develop an understanding of the fuel behavior during transient reactor scenarios. TRIGA fuels are composed of uranium (U) particles dispersed in a zirconium-hydride (Zr-H) matrix. In reactor, the fuel is encased in 304-stainless-steel (304SS) or Incoloy 800 clad tubes. At high temperatures, the fuel can readily interact with the cladding, resulting in FCCI. A number of FCCI can take place in this system. Interactions can be expected between the cladding and the Zr-H matrix, and/or between the cladding and the U-particles. Other interactions may be expected between the Zr-H matrix and the U-particles. Furthermore, the fuel contains erbium-oxide (Er-O) additions. Interactions can also be expected between the Er-O, the cladding, the Zr-H and the U-particles. The overall result is that very complex interactions may take place as a result of fuel and cladding exposures to high temperatures. This report discusses the characterization of the baseline fuel microstructure in the as-received state (prior to exposure to high temperature), characterization of the fuel after annealing at 950C for 24 hours and the results from diffusion couple experiments carries out at 1000C for 5 and 24 hours. Characterization was carried out via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with sample preparation via focused ion beam in situ-liftout-technique.

An Improved Quantum-Behaved Particle Swarm Optimization Method for Economic Dispatch Problems with Multiple Fuel Options and Valve-Points Effects

Directory of Open Access Journals (Sweden)

Hong-Yun Zhang

2012-09-01

Full Text Available Quantum-behaved particle swarm optimization (QPSO is an efficient and powerful population-based optimization technique, which is inspired by the conventional particle swarm optimization (PSO and quantum mechanics theories. In this paper, an improved QPSO named SQPSO is proposed, which combines QPSO with a selective probability operator to solve the economic dispatch (ED problems with valve-point effects and multiple fuel options. To show the performance of the proposed SQPSO, it is tested on five standard benchmark functions and two ED benchmark problems, including a 40-unit ED problem with valve-point effects and a 10-unit ED problem with multiple fuel options. The results are compared with differential evolution (DE, particle swarm optimization (PSO and basic QPSO, as well as a number of other methods reported in the literature in terms of solution quality, convergence speed and robustness. The simulation results confirm that the proposed SQPSO is effective and reliable for both function optimization and ED problems.

Gas phase deposition of oxide and metal-oxide coatings on fuel particles

International Nuclear Information System (INIS)

Patokin, A.P.; Khrebtov, V.L.; Shirokov, B.M.

2008-01-01

Production processes and properties of oxide (Al 2 O 3 , ZrO 2 ) and metal-oxide (Mo-Al 2 O 3 , Mo-ZrO 2 , W-Al 2 O 3 , W-ZrO 2 ) coatings on molybdenum substrates and uranium dioxide fuel particles were investigated. It is shown that the main factors that have an effect on the deposition rate, density, microstructure and other properties of coatings are the deposition temperature, the ratio of H 2 and CO 2 flow rates, the total reactor pressure and the ratio of partial pressures of corresponding metal chlorides during formation of metal-oxide coatings

A method for mapping the motion and temperature history of fuel particles in grate boilers and waste incinerators - stage 1; Metod foer kartlaeggning av braenslepartiklars roerelse och temperaturhistorik i rosterpannor/avfallsugnar - etapp 1

Energy Technology Data Exchange (ETDEWEB)

Gustavsson, Lennart; Blom, Elisabeth; Hald Pedersen, Niels; Moritz, Anders; Maardsjoe, Olle; Oskarsson, Jan; Petersson, Mats

2000-04-01

A feasibility study has been conducted where methods using radioactive tracer techniques for studying the behaviour of fuel particles on a grate are proposed and assessed. The following topics are addressed: - the possibility to continuously register the position of a single fuel particle on a grate from the fuel feed to burn-out; - the possibility to determine when a single fuel particle reach a certain temperature; and - the possibility to study drying and pyrolysis processes for a single fuel particle. In addition, a method to determine the height and density profiles of a fuel bed on a grate is proposed. The method for continuous determination of position is based on including a radiation source of the isotope {sup 24}Na in a fuel particle which is then supplied to the fuel feed. The gamma radiation emitted is registered by a number of detectors, mounted on the outside of the boiler. Since the radiation registered is dependent on both the distance between the source and detector and on the materials in the pathway, it is possible to continuously calculate the position of the fuel particle with the aid of Monte Carlo simulation. The inaccuracy in the determination is estimated to less than 5 cm. This is deemed to be accurate enough to be interesting. In order to study when a fuel particle reach a certain temperature, it is proposed that vials, manufactured in materials that will be broken at a defined temperature, is filled with the isotope {sup 85}Kr and mounted in fuel particles. When this noble gas is released, it follows the flue gases through the boiler and can be detected in the flue gas duct through its beta emission. The drying process of a fuel particle is proposed to be studied through impregnating fuel particles with tritium-containing water. The tritium-containing water is evaporated as the fuel particle dries and through analysing the tritium content of the flue gases the drying process can be followed. The feasibility study also deals with the

Characterization of Delayed-Particle Emission Signatures for Pyroprocessing. Part 1: ABTR Fuel Assembly.

Energy Technology Data Exchange (ETDEWEB)

Durkee, Jr., Joe W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-06-19

A three-part study is conducted using the MCNP6 Monte Carlo radiation-transport code to calculate delayed-neutron (DN) and delayed-gamma (DG) emission signatures for nondestructive assay (NDA) metal-fuel pyroprocessing. In Part 1, MCNP6 is used to produce irradiation-induced used nuclear fuel (UNF) isotopic inventories for an Argonne National Laboratory (ANL) Advanced Burner Test Reactor (ABTR) preconceptual design fuel assembly (FA) model. The initial fuel inventory consists of uranium mixed with light-water-reactor transuranic (TRU) waste and 10 wt% zirconium (U-LWR-SFTRU-10%Zr). To facilitate understanding, parametric evaluation is done using models for 3% and 5% initial ²³⁵U a% enrichments, burnups of 5, 10, 15, 20, 30, …, 120 GWd/MTIHM, and 3-, 5-, 10-, 20-, and 30- year cooling times. Detailed delayed-particle radioisotope source terms for the irradiate FA are created using BAMF-DRT and SOURCES3A. Using simulation tallies, DG activity ratios (DGARs) are developed for ¹³⁴Cs/¹³⁷Cs ¹³⁴Cs/¹⁵⁴Eu, and ¹⁵⁴Eu/¹³⁷Cs markers as a function of (1) burnup and (2) actinide mass, including elemental uranium, neptunium, plutonium, americium, and curium. Spectral-integrated DN emission is also tallied. The study reveals a rich assortment of DGAR behavior as a function of DGAR type, enrichment, burnup, and cooling time. Similarly, DN emission plots show variation as a function of burnup and of actinide mass. Sensitivity of DGAR and DN signatures to initial ²³⁵U enrichment, burnup, and cooling time is evident. Comparisons of the ABTR radiation signatures and radiation signatures previously reported for a generic Westinghouse oxide-fuel assembly indicate that there are pronounced differences in the ABTR and Westinghouse oxide-fuel DN and DG signatures. These differences are largely attributable to the initial TRU inventory in the ABTR fuel. The actinide and nonactinide inventories for the

Monte-Carlo simulation of dispersion fuel meat structure

International Nuclear Information System (INIS)

Xing Zhonghu; Ying Shihao

2003-01-01

Under the irradiation conditions in research reactors, the inter-diffusion occurs at the fuel particle and matrix interfaces of U 3 Si 2 -Al dispersion fuel. Because of the inter-diffusion reaction, the U 3 Al 7 Si 2 layer is formed around each U 3 Si 2 particle. The layer thickness grows up with irradiation duration and fission density. The formation of resultant layer causes the consumption of U 3 Si 2 fuel and aluminum matrix. This process leads to the evolution of geometrical structure of fuel meat. According to the stochastic locations of particles in dispersion, the authors developed a simulation method for the evolution of the fuel meat structure by utilizing Monte-Carlo method. Every particle is characterized by its diameter and location. The parameters of meat structure include particle size distribution, as-fabricated fuel volume fraction, resultant layer thickness, layer volume fraction, U 3 Si 2 fuel volume fraction, aluminum volume fraction, contiguity probability and inter-linkage fraction of particles. Particularly for the dispersion with as-fabricated fuel volume fraction of 43% and particle sizes in a well-defined normal distribution, more than 13000 sampling particles are simulated in the meat volume of 6 mm x 6 mm x 0.5 mm. The meat structure parameters are calculated as functions of layer thickness in the range from 0-16 μm. (authors)

Nuclear fuel element

International Nuclear Information System (INIS)

Grossman, L.N.; Levin, H.A.

1975-01-01

A nuclear fuel element has disposed therein an alloy having the essential components of nickel, titanium and zirconium, and the alloy reacts with water, water vapor and reactive gases at reactor ambient temperatures. The alloy is disposed in the plenum of the fuel element in the form of particles in a hollow gas permeable container having a multiplicity of openings of size smallr than the size of the particles. The container is preferably held in the spring in the plenum of the fuel element. (E.C.B.)

Nuclear fuel assemblies

International Nuclear Information System (INIS)

Butterfield, R.S.; Garner, D.L.M.

1977-01-01

Reference is made to nuclear fuel assemblies designed for cooling on the 'tube-in-shell' principle in which the fuel is contained by a shell and is cooled by coolant passed through tubes extending through the shell. It has been proposed to employ coated particle fuel as a porous bed on the tube side and the bleed coolant from the tubes into direct contact with the fuel particles. In this way heat is extracted both by direct contact with the fuel and by heat transfer through the coolant tube walls. The system described aims to provide an improved structure of tube and shell for a fuel assembly of this kind and is particularly suitable for use in a gas cooled fast reactor, being able to withstand the neutron flux and high temperature conditions in these reactors. Constructional details are given. (U.K.)

French programme for HTR fuel

International Nuclear Information System (INIS)

Gillet, R.M.

1991-01-01

It is reported that in the frameworks of the French HTR research program, stopped in 1979 the HTR coated particle fuel, fuel rod and prismatic fuel element design have been successfully developed and irradiation tested in France and specific examination methods for irradiated fuel particles, rods and graphite blocks have been developed. Currently CEA is involved in fission product transport experiments sponsored by the US Department of Energy and performed in the COMEDIE loop. Finally the CEA follows progress and developments in HTR fuel research and development throughout the world. 1 tab

Specialists' meeting on gas-cooled reactor fuel development and spent fuel treatment

Energy Technology Data Exchange (ETDEWEB)

NONE

1985-07-01

Topics covered during the 'Specialists' meeting on gas-cooled reactor fuel development and spent fuel treatment' were as follows: Selection of constructions and materials, fuel element development concepts; Fabrication of spherical coated fuel particles and fuel element on their base; investigation of fuel properties; Spent fuel treatment and storage; Head-end processing of HTGR fuel elements; investigation of HTGR fuel regeneration process; applicability of gas-fluorine technology of regeneration of spent HTGR fuel elements.

Specialists' meeting on gas-cooled reactor fuel development and spent fuel treatment

International Nuclear Information System (INIS)

1985-01-01

Topics covered during the 'Specialists' meeting on gas-cooled reactor fuel development and spent fuel treatment' were as follows: Selection of constructions and materials, fuel element development concepts; Fabrication of spherical coated fuel particles and fuel element on their base; investigation of fuel properties; Spent fuel treatment and storage; Head-end processing of HTGR fuel elements; investigation of HTGR fuel regeneration process; applicability of gas-fluorine technology of regeneration of spent HTGR fuel elements

Reconstruction of the size of nuclear fuel particle aerosol by the investigation of a radionuclide behaviour in body of the Chernobyl accident witnesses

International Nuclear Information System (INIS)

Kutkov, V.A.

1996-01-01

As a result of the Chernobyl NPP (ChNPP) accident aerosol particles of dispersed nuclear fuel were released to the atmosphere. Inhalation of those aerosol became the source of internal exposure for witnesses of the Chernobyl accident. To assess correctly internal doses from a mixture of radionuclides present in air in the form of aerosol particles one mast assign each radionuclide to a certain inhalation class by its chemical speciation in aerosol and define the airborne characteristics (the activity median aerodynamic diameter, AMAD and the standard geometric deviation, fig) of that particular aerosol. Moreover, information on any particular radionuclide is useless for other components since, in such a mixture, the radionuclides are generally independent and may belong to different particles. On the contrary, all nuclear fuel particle (NFP) radionuclides belong to the same particle, being matrix-bound. The collective behaviour of the matrix-bound radionuclides in the environment and in the human barrier organs makes it possible to spread to the aerosol of NFP any estimates of AMAD and β g obtained for any particular NFP radionuclide. This is principal feature of NFP aerosol as distinguished from a mere mixture of aerosol particles carry different radionuclides. (author)

Particle Swarm Optimization applied to combinatorial problem aiming the fuel recharge problem solution in a nuclear reactor

International Nuclear Information System (INIS)

Meneses, Anderson Alvarenga de Moura; Schirru, Roberto

2005-01-01

This work focuses on the usage the Artificial Intelligence technique Particle Swarm Optimization (PSO) to optimize the fuel recharge at a nuclear reactor. This is a combinatorial problem, in which the search of the best feasible solution is done by minimizing a specific objective function. However, in this first moment it is possible to compare the fuel recharge problem with the Traveling Salesman Problem (TSP), since both of them are combinatorial, with one advantage: the evaluation of the TSP objective function is much more simple. Thus, the proposed methods have been applied to two TSPs: Oliver 30 and Rykel 48. In 1995, KENNEDY and EBERHART presented the PSO technique to optimize non-linear continued functions. Recently some PSO models for discrete search spaces have been developed for combinatorial optimization. Although all of them having different formulation from the ones presented here. In this paper, we use the PSO theory associated with to the Random Keys (RK)model, used in some optimizations with Genetic Algorithms. The Particle Swarm Optimization with Random Keys (PSORK) results from this association, which combines PSO and RK. The adaptations and changings in the PSO aim to allow the usage of the PSO at the nuclear fuel recharge. This work shows the PSORK being applied to the proposed combinatorial problem and the obtained results. (author)

PIE Report on the KOMO-3 Irradiation Test Fuels

International Nuclear Information System (INIS)

Park, Jong Man; Ryu, H. J.; Yang, J. H.

2009-04-01

In the KOMO-3, in-reactor irradiation test had been performed for 12 kinds of dispersed U-Mo fuel rods, a multi wire fuel rod and a tube fuel rod. In this report we described the PIE results on the KOMO-3 irradiation test fuels. The interaction layer thickness between fuel particle and matrix could be reduced by using a large size U-Mo fuel particle or introducing Al-Si matrix or adding the third element in the U-Mo particle. Monolithic fuel rod of multi-wire or tube fuel was also effective in reducing the interaction layer thickness

Calculation simulation of equivalent irradiation swelling for dispersion nuclear fuel

International Nuclear Information System (INIS)

Cai Wei; Zhao Yunmei; Gong Xin; Ding Shurong; Huo Yongzhong

2015-01-01

The dispersion nuclear fuel was regarded as a kind of special particle composites. Assuming that the fuel particles are periodically distributed in the dispersion nuclear fuel meat, the finite element model to calculate its equivalent irradiation swelling was developed with the method of computational micro-mechanics. Considering irradiation swelling in the fuel particles and the irradiation hardening effect in the metal matrix, the stress update algorithms were established respectively for the fuel particles and metal matrix. The corresponding user subroutines were programmed, and the finite element simulation of equivalent irradiation swelling for the fuel meat was performed in Abaqus. The effects of the particle size and volume fraction on the equivalent irradiation swelling were investigated, and the fitting formula of equivalent irradiation swelling was obtained. The results indicate that the main factors to influence equivalent irradiation swelling of the fuel meat are the irradiation swelling and volume fraction of fuel particles. (authors)

Process for the production of fuel combined articles for addition in block shaped high temperature fuel elements

International Nuclear Information System (INIS)

Hrovat, M.; Rachor, L.

1976-01-01

There is provided a process for the production of fuel compacts consisting of an isotropic, radiation-resistant graphite matrix of good heat conductivity having embedded therein coated fuel and/or fertile particles for insertion into high temperature fuel elements by providing the coated fuel and/or fertile particles with an overcoat of molding mixture consisting of graphite powder and a thermoplastic resin binder. The particles after the overcoating are provided with hardener and lubricant only on the surface and subsequently are compressed in a die heated to a constant temperature of about 150 0 C, hardened and discharged therefrom as finished compacts

Irradiation test HT-31: high-temperature irradiation behavior of LASL-made extruded fuel rods and LASL-made coated particles

International Nuclear Information System (INIS)

Wagner, P.; Reiswig, R.D.; Hollabaugh, C.M.; White, R.W.; Davidson, K.V.; Schell, D.H.

1977-04-01

Three LASL-made extruded graphite and coated particle fuel rods have been irradiated in the Oak Ridge National Laboratory High Fluence Isotope Reactor test HT-31. Test conditions were about 9 x 10 21 nvt(E > .18 MeV) at 1250 0 C. The graphite matrix showed little or no effect of the irradiation. LASL-made ZrC containing coated particles with ZrC coats and ZrC-doped pyrolytic carbon coats showed no observable effects of the irradiation

HTGR fuel performance basis

International Nuclear Information System (INIS)

Shamasundar, B.I.; Stansfield, O.M.; Jensen, D.D.

1982-01-01

The safety characteristics of the high-temperature gas-cooled reactor (HTGR) during normal and accident conditions are determined in part by HTGR fuel performance. During normal operation, less than 0.1% fuel failure occurs, primarily from defective particles. This low fuel failure fraction limits circulating activity to acceptable levels. During severe accidents, the radiological consequence is influenced by high-temperature fuel particle behavior. An empirical fuel failure model, supported by recent experimental data, is presented. The onset of significant fuel particle failure occurs at temperatures in excess of 1600 0 C, and complete fuel failure occurs at 2660 0 C. This indicates that the fuel is more retentive at higher temperatures than previously assumed. The more retentive nature of the fuel coupled with the high thermal capacitance of the core results in slow release of fission products from the core during severe accidents. The slow release of fission products over hundreds of hours allows for decay of short-lived isotopes. The slow and limited release of fission products under HTGR accident conditions results in very low off-site doses. The slow nature of the accident provides more time for operator action to mitigate the accident and for local and state authorities to respond. These features can be used to take advantage of close-in siting for process applications, flexibility in site selection, and emergency planning

An investigation on fuel meats extruded with atomized U-10wt% Mo powder for uranium high-density dispersion fuel

International Nuclear Information System (INIS)

Kim, Chang-Kyu; Kim, Ki-Hwan; Park, Jong-Man; Lee, Don-Bae; Sohn, Dong-Seong

1997-01-01

The RERTR program has been making an effort to develop dispersion fuels with uranium densities of 8 to 9 g U/cm3 for research and test reactors. Using atomized U-10wt%Mo powder, fuel meats have been fabricated successfully up to 55 volume % of fuel powder. The uranium density of an extruded meat with a 55 volume % of fuel powder was obtained to be 7.7 g/cm3. A relatively high porosity of 7.3% was formed due to cracking of particles, presumably induced by the impingement among agglomerated particles. Tensile test results indicated that the strength of fuel meats with 55% volume fraction decreased some and a little of ductility was maintained. Examination on the fracture surface revealed that some U-10%Mo particles appeared to be broken by the tensile force in brittle rupture mode. The increase of broken particles in high fuel fraction is considered to be induced mainly by the impingement among agglomerated particles. Uranium loading density is assumed to be improved through the development of the better homogeneous dispersion technology. (author)

Reliability analysis of dispersion nuclear fuel elements

Science.gov (United States)

Ding, Shurong; Jiang, Xin; Huo, Yongzhong; Li, Lin an

2008-03-01

Taking a dispersion fuel element as a special particle composite, the representative volume element is chosen to act as the research object. The fuel swelling is simulated through temperature increase. The large strain elastoplastic analysis is carried out for the mechanical behaviors using FEM. The results indicate that the fission swelling is simulated successfully; the thickness increments grow linearly with burnup; with increasing of burnup: (1) the first principal stresses at fuel particles change from tensile ones to compression ones, (2) the maximum Mises stresses at the particles transfer from the centers of fuel particles to the location close to the interfaces between the matrix and the particles, their values increase with burnup; the maximum Mises stresses at the matrix exist in the middle location between the two particles near the mid-plane along the length (or width) direction, and the maximum plastic strains are also at the above region.

Reliability analysis of dispersion nuclear fuel elements

Energy Technology Data Exchange (ETDEWEB)

Ding Shurong [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China)], E-mail: dsr1971@163.com; Jiang Xin [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China); Huo Yongzhong [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China)], E-mail: yzhuo@fudan.edu.cn; Li Linan [Department of Mechanics, Tianjin University, Tianjin 300072 (China)

2008-03-15

Taking a dispersion fuel element as a special particle composite, the representative volume element is chosen to act as the research object. The fuel swelling is simulated through temperature increase. The large strain elastoplastic analysis is carried out for the mechanical behaviors using FEM. The results indicate that the fission swelling is simulated successfully; the thickness increments grow linearly with burnup; with increasing of burnup: (1) the first principal stresses at fuel particles change from tensile ones to compression ones, (2) the maximum Mises stresses at the particles transfer from the centers of fuel particles to the location close to the interfaces between the matrix and the particles, their values increase with burnup; the maximum Mises stresses at the matrix exist in the middle location between the two particles near the mid-plane along the length (or width) direction, and the maximum plastic strains are also at the above region.

Method to manufacture spherical fuel and breeder particles

International Nuclear Information System (INIS)

Huschka, H.; Kadner, M.

1976-01-01

Optimum properties of the pyrolytic carbon cladding layer deposited on fuel and breeder cores are best achieved by forming the layers into exact spherical shells. It is necessary to have a uniform shperical shape of the cores to be coated. This is achieved by converting an oscillating liquid jet flowing out of one or several nozzles, of uranium and/or thorium solutions which drop into an ammonia solution at a quantity of over 3000 drops per minute. The drops prior to plunging into the ammonia solution, according to the invention, firstly run through an ammonia gasfree fall to acquire the shperical shape, then they fall through a zone flowed-through by ammonia gas. The ammonia gas is introduced into the dropping zone so that it flows in the opposite direction to falling and so that in addition a horizontal cross-flowing of the gas between the drops is guaranteed. The spherical drops are thus hardened before entering the ammonia solution. They are then washed as usual, dried and sintered. 4 examples are given to prepare thorium dioxide, uranium carbide and (U,Th) mixed oxide particles. (IHOE) [de

A study of fuel failure behavior in high burnup HTGR fuel. Analysis by STRESS3 and STAPLE codes

International Nuclear Information System (INIS)

Martin, David G.; Sawa, Kazuhiro; Ueta, Shouhei; Sumita, Junya

2001-05-01

In current high temperature gas-cooled reactors (HTGRs), Tri-isotropic coated fuel particles are employed as fuel. In safety design of the HTGR fuels, it is important to retain fission products within particles so that their release to primary coolant does not exceed an acceptable level. From this point of view, the basic design criteria for the fuel are to minimize the failure fraction of as-fabricated fuel coating layers and to prevent significant additional fuel failures during operation. This report attempts to model fuel behavior in irradiation tests using the U.K. codes STRESS3 and STAPLE. Test results in 91F-1A and HRB-22 capsules irradiation tests, which were carried out at the Japan Materials Testing Reactor of JAERI and at the High Flux Isotope Reactor of Oak Ridge National Laboratory, respectively, were employed in the calculation. The maximum burnup and fast neutron fluence were about 10%FIMA and 3 x 10 25 m -2 , respectively. The fuel for the irradiation tests was called high burnup fuel, whose target burnup and fast neutron fluence were higher than those of the first-loading fuel of the High Temperature Engineering Test Reactor. The calculation results demonstrated that if only mean fracture stress values of PyC and SiC are used in the calculation it is not possible to predict any particle failures, by which is meant when all three load bearing layers have failed. By contrast, when statistical variations in the fracture stresses and particle specifications are taken into account, as is done in the STAPLE code, failures can be predicted. In the HRB-22 irradiation test, it was concluded that the first two particles which had failed were defective in some way, but that the third and fourth failures can be accounted for by the pressure vessel model. In the 91F-1A irradiation test, the result showed that 1 or 2 particles had failed towards the end of irradiation in the upper capsule and no particles failed in the lower capsule. (author)

Brittle-fracture statistics for the determination of the strength of fuel particle coatings

International Nuclear Information System (INIS)

Bongartz, K.; Schuster, H.

1976-04-01

Two influences on characteristic strength values of brittle materials were investigated: the specimen number which is limited in the laboratory by practical reasons, and the procedure for fitting the Weibull formalism to experimental results. The study was performed with respect to the evaluation of the strength of coatings of HTR-fuel particles. Strength values following Weibull statistics were produced artificially to simulate experimental results. The applicability of four different methods was studied to get best fits of the Weibull parameters to these values. The relation of the scatter of strength values and Weibull parameter to the specimen number is determined. (orig./GSCH) [de

Optimization of fuel core loading pattern design in a VVER nuclear power reactors using Particle Swarm Optimization (PSO)

International Nuclear Information System (INIS)

Babazadeh, Davood; Boroushaki, Mehrdad; Lucas, Caro

2009-01-01

The two main goals in core fuel loading pattern design optimization are maximizing the core effective multiplication factor (K eff ) in order to extract the maximum energy, and keeping the local power peaking factor (P q ) lower than a predetermined value to maintain fuel integrity. In this research, a new strategy based on Particle Swarm Optimization (PSO) algorithm has been developed to optimize the fuel core loading pattern in a typical VVER. The PSO algorithm presents a simple social model by inspiration from bird collective behavior in finding food. A modified version of PSO algorithm for discrete variables has been developed and implemented successfully for the multi-objective optimization of fuel loading pattern design with constraints of keeping P q lower than a predetermined value and maximizing K eff . This strategy has been accomplished using WIMSD and CITATION calculation codes. Simulation results show that this algorithm can help in the acquisition of a new pattern without contravention of the constraints.

Aerosols from biomass combustion. Particle formation, relevance on air quality, and measures for particle reduction

International Nuclear Information System (INIS)

Nussbaumer, Thomas

2005-01-01

Biomass combustion is a relevant source of particle emissions. In Switzerland, wood combustion contributes with 2% to the energy supply but with more than 4% to Particulate Matter smaller 10 microns (PM 10) in the ambient air. In areas with high density of residential wood heating (e.g. in the south of Chile), wood particles are the dominant source of PM 10 resulting in heavy local smog situations. Since combustion particles are regarded as health relevant and since immission limit values on PM 10 are widely exceeded, measures for particle reduction from biomass combustion are of high priority. With respect to aerosols from biomass combustion, two sources of particles are distinguished: 1. an incomplete combustion can lead to soot and organic matter contained in the particles, 2. ash constituents in the fuel lead to the formation of inorganic fly ash particles mainly consisting of salts such as chlorides and oxides. The theory of aerosol formation from fuel constituents is described and two hypotheses to reduce inorganic particles from biomass combustion are proposed: 1. a reduced oxygen content in the solid fuel conversion zone (glow bed in a fixed bed combustion) is assumed to reduce the particle mass concentration due to three mechanisms: a) reduced oxidation of fuel constituents to compounds with higher volatility, b) reduced local temperature for solid fuel conversion, c) a reduced entrainmed of fuel constituents 2. a reduced total excess air can reduce the particle number due to enhanced coagulation. The proposed low-particle concept has been implemented for an automatic furnace for wood pellets in the size range from 100 kW to 500 kW. Furthermore, the furnace design was optimised to enable a part load operation without increased emissions of carbon monoxide (CO) and particles. In a 100 kW prototype furnace the low-particle conditions resulted in particle emissions between 6 mg/m n 3 to 11 mg/m n 3 at 13 vol.-% O2 and CO emissions below 70 mg/m n 3 in the

Studies of fuel loading pattern optimization for a typical pressurized water reactor (PWR) using improved pivot particle swarm method

International Nuclear Information System (INIS)

Liu, Shichang; Cai, Jiejin

2012-01-01

Highlights: ► The mathematical model of loading pattern problems for PWR has been established. ► IPPSO was integrated with ‘donjon’ and ‘dragon’ into fuel arrangement optimizing code. ► The novel method showed highly efficiency for the LP problems. ► The core effective multiplication factor increases by about 10% in simulation cases. ► The power peaking factor decreases by about 0.6% in simulation cases. -- Abstract: An in-core fuel reload design tool using the improved pivot particle swarm method was developed for the loading pattern optimization problems in a typical PWR, such as Daya Bay Nuclear Power Plant. The discrete, multi-objective improved pivot particle swarm optimization, was integrated with the in-core physics calculation code ‘donjon’ based on finite element method, and assemblies’ group constant calculation code ‘dragon’, composing the optimization code for fuel arrangement. The codes of both ‘donjon’ and ‘dragon’ were programmed by Institute of Nuclear Engineering of Polytechnique Montréal, Canada. This optimization code was aiming to maximize the core effective multiplication factor (Keff), while keeping the local power peaking factor (Ppf) lower than a predetermined value to maintain fuel integrity. At last, the code was applied to the first cycle loading of Daya Bay Nuclear Power Plant. The result showed that, compared with the reference loading pattern design, the core effective multiplication factor increased by 9.6%, while the power peaking factor decreased by 0.6%, meeting the safety requirement.

A two-group study on the gadolinium particle depletion in light water reactor fuel rods

International Nuclear Information System (INIS)

Lee, C.

1989-01-01

The effect of gadolinia particles on the assembly criticality of a light water reactor was investigated using two 2-group models. The particle effect was calculated by comparing the criticalities of two fuel assemblies, each containing one gadolinia-poisoned rod. For purposes of comparison, both rods contained an equal quantity of gadolinia, but the gadolinia fraction in one rod was in particle form. It was assumed that one pseudo-isotope represented Gd-155 and Gd-157, while the other isotopes were not considered. A one-group model developed by Kenneth Hartley(KH), was expanded into a two-group model, using a flat distribution for the fast group neutron flux. Gadolinia density was uniformly reduced by fast neutrons and the gadolinia burnup-rate was increased. The transparency effect of the gadolinia core was also included in the two group-KH model, allowing predictions of smoother changes at the peak of Δk (difference between k of the particle rod assembly and k of the uniform rod assembly). The Oregon State University Collision Probability (OSUCP) two-group model was developed for the investigation of the inter-particle shielding effect. A collision probability method was used to calculate thermal flux, and the flat fast-group flux assumption was used. The results of this study indicated that for small, 10-micron particles, the KH model failed to predict correct Δk behavior for the two assemblies. However, for larger, 100-micron particles both models well in agreement for the Δk profile, and for 500-micron particles both models were in agreement on both the behavior and magnitude of Δk

Phase analyses of silicide or nitride coated U–Mo and U–Mo–Ti particle dispersion fuel after out-of-pile annealing

Energy Technology Data Exchange (ETDEWEB)

Kim, Woo Jeong [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong, Daejeon 305-353 (Korea, Republic of); Palancher, Hervé [CEA, DEN, DEC, F-13108 Saint Paul Lez Durance Cedex (France); Ryu, Ho Jin, E-mail: hojinryu@kaist.ac.kr [Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong, Daejeon 305-701 (Korea, Republic of); Park, Jong Man; Nam, Ji Min [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong, Daejeon 305-353 (Korea, Republic of); Bonnin, Anne [CEA, DEN, DEC, F-13108 Saint Paul Lez Durance Cedex (France); ESRF, 6, rue J. Horowitz, F-38000 Grenoble Cedex (France); Honkimäki, Veijo [ESRF, 6, rue J. Horowitz, F-38000 Grenoble Cedex (France); Charollais, François [CEA, DEN, DEC, F-13108 Saint Paul Lez Durance Cedex (France); Lemoine, Patrick [CEA, DEN, DISN, 91191 Gif sur Yvette (France)

2014-03-15

Highlights: • Silicide or nitride layers were coated on atomized U–Mo or U–Mo–Ti powder. • The constituent phases after annealing were identified through high-energy XRD. • U{sub 3}Si{sub 5} and U{sub 4}Mo(Mo{sub x}Si{sub 1−x})Si{sub 2} were identified in the silicide coating layers. • UN was identified for U–Mo particles and UN and U{sub 4}N{sub 7} formed on U–Mo–Ti particles. -- Abstract: The coating of silicide or nitride layers on U–7 wt%Mo or U–7 wt%Mo–1 wt%Ti particles has been proposed for the minimization of the interaction phase growth in U–Mo/Al dispersion fuel during irradiation. Out-of-pile annealing tests show reduced inter-diffusion by forming silicide or nitride protective layers on U–Mo and U–Mo–Ti particles. To characterize the constituent phases of the coated layers on U–Mo and U–Mo–Ti particles and the interaction phases of coated U–Mo and U–Mo–Ti particle dispersed Al matrix fuel, synchrotron X-ray diffraction experiments have been performed. It was identified that silicide coating layers consisted mainly of U{sub 3}Si{sub 5} and U{sub 4}Mo(Mo{sub x}Si{sub 1−x})Si{sub 2}, and nitride coating layers were composed of mainly UN and U{sub 4}N{sub 7}. The interaction phases obtained after annealing of coated U–Mo and U–Mo–Ti particle dispersion samples were identical to those found in U–Mo/Al–Si and U–Mo/Al systems. Nitride-coated particles showed less interaction formation than silicide-coated particles after annealing at 580 °C for 1 h owing to the higher susceptibility to breakage of the silicide coating layers during hot extrusion.

In situ laser measurements of CO and CH{sub 4} close to the surface of a burning single fuel particle

Energy Technology Data Exchange (ETDEWEB)

Lackner, M.; Totschnig, G.; Winter, F.; Maiorov, M.A.; Garbuzov, D.Z.; Connolly, J.C. [Vienna University of Technolgy, Vienna (Austria). Inst. of Chemical Engineering

2002-07-01

The combustion behaviour of three different fuels, bituminous coal, beech wood and fir wood, was investigated by monitoring the concentrations of CO, CH{sub 4}, CO{sub 2} and O{sub 2} during devolatilization and char combustion. Single fuel particles (4-6 mm diameter, 55 mm in length) were positioned in the freeboard of a laboratory-scale fluidized bed combustor. The superficial velocity was 0.3 m s{sup -1}. Tunable diode laser absorption spectroscopy was used to investigate in situ the concentration histories of the evolving species CO and CH{sub 4}. An InGaAsSb/AlGaAsSb diode laser was frequency tuned around 2.3/{mu}m at 300 Hz and traversed the reactor directly above the particle. This enabled the accurate measurement of species concentrations close to the surface of a burning particle. The influence of the oxygen partial pressure (5, 10, 15, 21 kPa), the bed temperature (700, 800, 900{sup o}C), the distance of the laser beam from the particle (4, 10, 21, 31 mm) and hence the residence time (12, 30, 60, 90 ms), the particle size (4, 6 {mu}m diameter) and the fuel type were investigated by independently changing these governing parameters. Conventional methods were deployed to determine CO, CO{sub 2} and O{sub 2} in the exhaust gas. The evolving CO could be tracked down to 12 ms after its generation. Biomass was found to produce four times as much CO as coal. The CO/CO{sub 2} ratio was found to be about five times higher for beech wood (a typical hardwood) than for fir wood (a typical softwood). The comparison of the in situ results with conventionally measured concentrations showed that the CO is normally underestimated during devolatilization and overestimated during char combustion. The discrepancy was attributed to more efficient degradation mechanisms for CO during devolatilization.

Analysis of Transition from HCCI to CI via PPC with Low Octane Gasoline Fuels Using Optical Diagnostics and Soot Particle Analysis

KAUST Repository

An, Yanzhao; Vallinayagam, R; Vedharaj, S; Masurier, Jean-Baptiste; Dawood, Alaaeldin; Izadi Najafabadi, Mohammad; Somers, Bart; Johansson, Bengt

2017-01-01

In-cylinder visualization, combustion stratification, and engine-out particulate matter (PM) emissions were investigated in an optical engine fueled with Haltermann straight-run naphtha fuel and corresponding surrogate fuel. The combustion mode was transited from homogeneous charge compression ignition (HCCI) to conventional compression ignition (CI) via partially premixed combustion (PPC). Single injection strategy with the change of start of injection (SOI) from early to late injections was employed. The high-speed color camera was used to capture the in-cylinder combustion images. The combustion stratification was analyzed based on the natural luminosity of the combustion images. The regulated emission of unburned hydrocarbon (UHC), carbon monoxide (CO) and nitrogen oxides (NO) were measured to evaluate the combustion efficiency together with the in-cylinder rate of heat release. Soot mass concentration was measured and linked with the combustion stratification and the integrated red channel intensity of the high-speed images for the soot emissions. The nucleation nanoscale particle number and the particle size distribution were sampled to understand the effect of combustion mode switch.

Analysis of Transition from HCCI to CI via PPC with Low Octane Gasoline Fuels Using Optical Diagnostics and Soot Particle Analysis

KAUST Repository

An, Yanzhao

2017-10-10

In-cylinder visualization, combustion stratification, and engine-out particulate matter (PM) emissions were investigated in an optical engine fueled with Haltermann straight-run naphtha fuel and corresponding surrogate fuel. The combustion mode was transited from homogeneous charge compression ignition (HCCI) to conventional compression ignition (CI) via partially premixed combustion (PPC). Single injection strategy with the change of start of injection (SOI) from early to late injections was employed. The high-speed color camera was used to capture the in-cylinder combustion images. The combustion stratification was analyzed based on the natural luminosity of the combustion images. The regulated emission of unburned hydrocarbon (UHC), carbon monoxide (CO) and nitrogen oxides (NO) were measured to evaluate the combustion efficiency together with the in-cylinder rate of heat release. Soot mass concentration was measured and linked with the combustion stratification and the integrated red channel intensity of the high-speed images for the soot emissions. The nucleation nanoscale particle number and the particle size distribution were sampled to understand the effect of combustion mode switch.

Anisotropy variation of crystallographic orientation in pyrocarbon coatings of fuel particles by annealing and neutron irradiation

Energy Technology Data Exchange (ETDEWEB)

Koizlik, K.

1973-04-15

This document is a translation of those parts of the German report Jul-868-RW concerned with changes in anisotropy as determined using an optical technique on pyrocarbon coatings on fuel particles resulting from annealing and neutron irradiations. Two lists of contents are included, one is for the present document and the other is the full contents of the original report and is included for the generl interest of users.

Effects of fueling profiles on plasma transport

International Nuclear Information System (INIS)

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

1977-01-01

The effects of cold particle fueling profiles on particle and energy transport in an ignition sized tokamak plasma are investigated in this study with a one-dimensional, multifluid transport model. A density gradient driven trapped particle microinstability model for plasma transport is used to demonstrate potential effects of fueling profiles on ignition requirements. Important criteria for the development of improved transport models under the conditions of shallow particle fueling profiles are outlined. A discrete pellet fueling model indicates that large fluctuations in density and temperature may occur in the outer regions of the plasma with large, shallowly penetrating pellets, but fluctuations in the pressure profile are small. The hot central core of the plasma remains unaffected by the large fluctuations near the plasma edge

Evolution of dispersion fuel meat structure caused by interface reaction

International Nuclear Information System (INIS)

Xing Zhonghu; Ying Shihao

2000-01-01

In reactor operation, the resultant layers are formed by interdiffusion at the fuel particle-matrix interfaces of U 3 Si 2 -Al dispersion fuel. This results in the evolution of meat structure. On the basis of Monte-Carlo method, the author developed simulation method of fuel meat, and simulated the stochastic space locations of spherical fuel particles in the meat. The fuel volume fraction is 43%, and the particles are in definite size distribution. For the 13551 simulated particle samples, the evolution of meat structure is calculated with layer thickness ranging from 0 to 16 μm. The parameters of meat structure include the U 3 Si 2 fuel volume fraction, resultant layer volume fraction, Al matrix volume fraction, particle contact probability and overlap degree as functions of layer thickness

Modeling of solid oxide fuel cells with particle size and porosity grading in anode electrode

Energy Technology Data Exchange (ETDEWEB)

Liu, L.; Flesner, R.; Kim, G.Y.; Chandra, A. [Department of Mechanical Engineering, Iowa State University, Ames, Iowa (United States)

2012-02-15

Solid oxide fuel cells (SOFCs) have the potential to meet the critical energy needs of our modern civilization and minimize the adverse environmental impacts from excessive energy consumption. They are highly efficient, clean, and can run on variety of fuel gases. However, little investigative focus has been put on optimal power output based on electrode microstructure. In this work, a complete electrode polarization model of SOFCs has been developed and utilized to analyze the performance of functionally graded anode with different particle size and porosity profiles. The model helps to understand the implications of varying the electrode microstructure from the polarization standpoint. The work identified conditions when grading can improve the cell performance and showed that grading is not always beneficial or necessary. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Fabrication and characterization of fully ceramic microencapsulated fuels

Energy Technology Data Exchange (ETDEWEB)

Terrani, K.A., E-mail: kurt.terrani@gmail.com [Fuel Cycle and Isotopes Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kiggans, J.O.; Katoh, Y. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Shimoda, K. [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Montgomery, F.C.; Armstrong, B.L.; Parish, C.M. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Hinoki, T. [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Hunn, J.D. [Fuel Cycle and Isotopes Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Snead, L.L. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2012-07-15

The current generation of fully ceramic microencapsulated fuels, consisting of Tristructural Isotropic fuel particles embedded in a silicon carbide matrix, is fabricated by hot pressing. Matrix powder feedstock is comprised of alumina-yttria additives thoroughly mixed with silicon carbide nanopowder using polyethyleneimine as a dispersing agent. Fuel compacts are fabricated by hot pressing the powder-fuel particle mixture at a temperature of 1800-1900 Degree-Sign C using compaction pressures of 10-20 MPa. Detailed microstructural characterization of the final fuel compacts shows that oxide additives are limited in extent and are distributed uniformly at silicon carbide grain boundaries, at triple joints between silicon carbide grains, and at the fuel particle-matrix interface.

Temperature of loose coated particles in irradiation tests

International Nuclear Information System (INIS)

Conlin, J.A.

1975-04-01

An analysis is presented of the temperature of a monolayer bed of loose High-Temperature Gas-Cooled Reactor (HTGR) type fissioning fuel particles in an annular cavity. Both conduction and radiant heat transfer are taken into account, and the effect of particle contact with the annular cavity surfaces is evaluated. Charts are included for the determination of the maximum surface temperature of the particle coating for any size particle or power generation rate in a fuel bed of this type. The charts are intended for the design and evaluation of irradiation experiments on loose beds of coated fuel particles of the type used in HTGRs. Included in an Appendix is a method for estimating the temperature of a particle in circular hole. (U.S.)

TRISO coated fuel particles with enhanced SiC properties

International Nuclear Information System (INIS)

Lopez-Honorato, E.; Tan, J.; Meadows, P.J.; Marsh, G.; Xiao, P.

2009-01-01

The silicon carbide (SiC) layer used for the formation of TRISO coated fuel particles is normally produced at 1500-1650 deg. C via fluidized bed chemical vapor deposition from methyltrichlorosilane in a hydrogen environment. In this work, we show the deposition of SiC coatings with uniform grain size throughout the coating thickness, as opposed to standard coatings which have larger grain sizes in the outer sections of the coating. Furthermore, the use of argon as the fluidizing gas and propylene as a carbon precursor, in addition to hydrogen and methyltrichlorosilane, allowed the deposition of stoichiometric SiC coatings with refined microstructure at 1400 and 1300 deg. C. The deposition of SiC at lower deposition temperatures was also advantageous since the reduced heat treatment was not detrimental to the properties of the inner pyrolytic carbon which generally occurs when SiC is deposited at 1500 deg. C. The use of a chemical vapor deposition coater with four spouts allowed the deposition of uniform and spherical coatings.

Particle Emissions from Domestic Gas Cookers

DEFF Research Database (Denmark)

Glarborg, Peter; Livbjerg, Hans; Wagner, Ayten Yilmaz

2010-01-01

The authors experimentally studied the formation of submicron particles from a domestic gas cooker in a compartment free from external particle sources. The effects of fuel (methane, natural gas, odorant-free natural gas), primary aeration, flow rate, and fuel sulphur content on particle emissions...... of the emitted particles were found to have a mean value of about 7 nm for partially premixed flames, increasing to ∼10 nm for nonpremixed flames. The quantity of primary air had a strong impact on the particle emissions, showing a minimum at a primary aeration level of 60-65%. Presence of sulphur in small...... quantities may enhance particle formation under some conditions, but results were not conclusive....

Influence of Particle Size Distribution on the Morphology and Cavitation Resistance of High-Velocity Oxygen Fuel Coatings

Science.gov (United States)

Silveira, L. L.; Sucharski, G. B.; Pukasiewicz, A. G. M.; Paredes, R. S. C.

2018-02-01

The cavitation wear process is one of the major wear mechanisms in turbines and rotors of hydroelectric power plants in Brazil. An effective way to increase the cavitation resistance is the use of coatings, applied by thermal spraying. The high-velocity oxy-fuel process (HVOF) is one of the most used thermal spraying processes, and it is widely adopted for applying coatings for protection against wear and in maintenance components. A FeCrMnSiB experimental alloy was deposited onto SAE 1020 substrate by HVOF process, in order to evaluate the influence of the powder particle size range on the morphology and cavitation resistance of the coatings. The morphology of the coatings showed an increase in oxide content with powder size reduction. The increase in the powder particle size reduced the wettability of the particles, observed by the increase in the quantity of non-melted particles. Higher particle size distribution led to an increase in erosion rate, due to higher presence of non-melted particles in the coatings and consequently reduction of splats adhesion. The cavitation damage was perceived mainly by the mechanism of lamellae detachment; however, part of the damage was also absorbed by strain hardening due to the γ-ɛ martensitic transformation.

Influence of Particle Size Distribution on the Morphology and Cavitation Resistance of High-Velocity Oxygen Fuel Coatings

Science.gov (United States)

Silveira, L. L.; Sucharski, G. B.; Pukasiewicz, A. G. M.; Paredes, R. S. C.

2018-04-01

The cavitation wear process is one of the major wear mechanisms in turbines and rotors of hydroelectric power plants in Brazil. An effective way to increase the cavitation resistance is the use of coatings, applied by thermal spraying. The high-velocity oxy-fuel process (HVOF) is one of the most used thermal spraying processes, and it is widely adopted for applying coatings for protection against wear and in maintenance components. A FeCrMnSiB experimental alloy was deposited onto SAE 1020 substrate by HVOF process, in order to evaluate the influence of the powder particle size range on the morphology and cavitation resistance of the coatings. The morphology of the coatings showed an increase in oxide content with powder size reduction. The increase in the powder particle size reduced the wettability of the particles, observed by the increase in the quantity of non-melted particles. Higher particle size distribution led to an increase in erosion rate, due to higher presence of non-melted particles in the coatings and consequently reduction of splats adhesion. The cavitation damage was perceived mainly by the mechanism of lamellae detachment; however, part of the damage was also absorbed by strain hardening due to the γ- ɛ martensitic transformation.

HTGR fuel behavior at very high temperature

International Nuclear Information System (INIS)

Kashimura, Satoru; Ogawa, Touru; Fukuda, Kousaku; Iwamoto, Kazumi

1986-03-01

Fuel behavior at very high temperature simulating abnormal transient of the reactor operation and accidents have been investigated on TRISO coating LEU oxide particle fuels at JAERI. The test simulating the abnormal transient was carried out by irradiation of loose coated particles above 1600 deg C. The irradiation test indicated that particle failure was principally caused by kernel migration. For simulation of the core heat-up accident, two experiments of out-of-pile heating were made. Survival temperature limits were measured and fuel performance at very high temperature were investigated by the heatings. Study on the fuel behavior under reactivity initiated accident was made by NSRR(Nuclear Safety Research Reactor) pulse irradiation, where maximum temperature was higher than 2800 deg C. It was found in the pulse irradiation experiments that the coated particles incorporated in the compacts did not so severely fail unlike the loose coated particles at ultra high temperature above 2800 deg C. In the former particles UO 2 material at the center of the kernel vaporized, leaving a spherical void. (author)

Particle bed reactor nuclear rocket concept

International Nuclear Information System (INIS)

Ludewig, H.

1991-01-01

The particle bed reactor nuclear rocket concept consists of fuel particles (in this case (U,Zr)C with an outer coat of zirconium carbide). These particles are packed in an annular bed surrounded by two frits (porous tubes) forming a fuel element; the outer one being a cold frit, the inner one being a hot frit. The fuel element are cooled by hydrogen passing in through the moderator. These elements are assembled in a reactor assembly in a hexagonal pattern. The reactor can be either reflected or not, depending on the design, and either 19 or 37 elements, are used. Propellant enters in the top, passes through the moderator fuel element and out through the nozzle. Beryllium used for the moderator in this particular design to withstand the high radiation exposure implied by the long run times

Modeling a failure criterion for U-Mo/Al dispersion fuel

Science.gov (United States)

Oh, Jae-Yong; Kim, Yeon Soo; Tahk, Young-Wook; Kim, Hyun-Jung; Kong, Eui-Hyun; Yim, Jeong-Sik

2016-05-01

The breakaway swelling in U-Mo/Al dispersion fuel is known to be caused by large pore formation enhanced by interaction layer (IL) growth between fuel particles and Al matrix. In this study, a critical IL thickness was defined as a criterion for the formation of a large pore in U-Mo/Al dispersion fuel. Specifically, the critical IL thickness is given when two neighboring fuel particles come into contact with each other in the developed IL. The model was verified using the irradiation data from the RERTR tests and KOMO-4 test. The model application to full-sized sample irradiations such as IRISs, FUTURE, E-FUTURE, and AFIP-1 tests resulted in conservative predictions. The parametric study revealed that the fuel particle size and the homogeneity of the fuel particle distribution are influential for fuel performance.

Modeling a failure criterion for U–Mo/Al dispersion fuel

Energy Technology Data Exchange (ETDEWEB)

Oh, Jae-Yong, E-mail: tylor@kaeri.re.kr [Korea Atomic Energy Research Institute, 111, Daedeok-Daero 989 Beon-Gil, Yuseong-Gu, Daejeon 305-353 (Korea, Republic of); Kim, Yeon Soo [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Tahk, Young-Wook; Kim, Hyun-Jung; Kong, Eui-Hyun; Yim, Jeong-Sik [Korea Atomic Energy Research Institute, 111, Daedeok-Daero 989 Beon-Gil, Yuseong-Gu, Daejeon 305-353 (Korea, Republic of)

2016-05-15

The breakaway swelling in U–Mo/Al dispersion fuel is known to be caused by large pore formation enhanced by interaction layer (IL) growth between fuel particles and Al matrix. In this study, a critical IL thickness was defined as a criterion for the formation of a large pore in U–Mo/Al dispersion fuel. Specifically, the critical IL thickness is given when two neighboring fuel particles come into contact with each other in the developed IL. The model was verified using the irradiation data from the RERTR tests and KOMO-4 test. The model application to full-sized sample irradiations such as IRISs, FUTURE, E-FUTURE, and AFIP-1 tests resulted in conservative predictions. The parametric study revealed that the fuel particle size and the homogeneity of the fuel particle distribution are influential for fuel performance.

Method for the fabrication of nuclear fuel bodies

International Nuclear Information System (INIS)

Davis, D.E.; Leary, D.F.

1976-01-01

According to the method, graphite particles are treated with a liquid impregnating agent containing heat-hardenable resin components; the resulting particles are mixed with nuclear fuel particles, and a nuclear fuel body is formed by binding the mixture of particles into a cohesive mass by means of a carbon-contained binder. The claim concerns the details of the process. (UA) [de

Experimental design for HTGR fuel rods

International Nuclear Information System (INIS)

Bayne, C.K.

1975-01-01

Fuel rods for the high temperature gas cooled reactor are composed of pyrolytic carbon coated fuel particles bounded by a carbonaceous matrix. Because of differential shrinkage between coated particles and the carbonaceous matrix, breakage of the pyrolytic coating has been observed with certain combinations of coated particles and matrix compositions. The pyrolytic coating is intended to be the primary containment for fission products. Therefore, an experiment is desired to determine the breakage characteristics of different strength coated particles combined with different matrix compositions during irradiation

Effects of Low Sulfur Fuel and a Catalyzed Particle Trap on the Composition and Toxicity of Diesel Emissions

Science.gov (United States)

McDonald, Jacob D.; Harrod, Kevin S.; Seagrave, JeanClare; Seilkop, Steven K.; Mauderly, Joe L.

2004-01-01

In this study we compared a “baseline” condition of uncontrolled diesel engine exhaust (DEE) emissions generated with current (circa 2003) certification fuel to an emissions-reduction (ER) case with low sulfur fuel and a catalyzed particle trap. Lung toxicity assessments (resistance to respiratory viral infection, lung inflammation, and oxidative stress) were performed on mice (C57Bl/6) exposed by inhalation (6 hr/day for 7 days). The engine was operated identically (same engine load) in both cases, and the inhalation exposures were conducted at the same exhaust dilution rate. For baseline DEE, this dilution resulted in a particle mass (PM) concentration of approximately 200 μg/m3 PM, whereas the ER reduced the PM and almost every other measured constituent [except nitrogen oxides (NOx)] to near background levels in the exposure atmospheres. These measurements included PM, PM size distribution, PM composition (carbon, ions, elements), NOx, carbon monoxide, speciated/total volatile hydrocarbons, and several classes of semi-volatile organic compounds. After exposure concluded, one group of mice was immediately sacrificed and assessed for inflammation and oxidative stress in lung homogenate. Another group of mice were intratracheally instilled with respiratory syncytial virus (RSV), and RSV lung clearance and inflammation was assessed 4 days later. Baseline DEE produced statistically significant biological effects for all measured parameters. The use of low sulfur fuel and a catalyzed trap either completely or nearly eliminated the effects. PMID:15345344

Studies of fuel-bulk flows using charged-particle and neutron spectrometry on OMEGA and the NIF

Science.gov (United States)

Gatu Johnson, M.; Rinderknecht, H.; Rosenberg, M.; Sio, H.; Zylstra, A.; Frenje, J.; Li, C. K.; Seguin, F.; Petrasso, R.; Delettrez, J.; Glebov, V.; Knauer, J.; McKenty, P.; Sangster, T. C.; Appelbe, B.; Amendt, P.; Bellei, C.; Bionta, R.; Bleuel, D.; Caggiano, J.; Casey, D.; Edwards, J.; Hatarik, R.; Hatchett, S.; Landen, O.

2013-10-01

A. MACKINNON, J. MCNANEY, D. MUNRO, J. PINO, S. WILKS, C. YEAMANS, LLNL, J. KILKENNY, A. NIKROO, GA - Charged-particle and neutron spectra are used to study fuel-bulk flows, which are indicative of implosion asymmetries and inefficient conversion of kinetic energy to thermal energy. We distinguish between (i) collective, directional motion of the burn region, which manifests itself as a directional shift of the fusion-product spectrum, and (ii) radial flow, which appears as an additional broadening of the spectrum relative to expected based on Ti Doppler broadening. In this talk, we will present neutron and charged particle spectra from OMEGA and the NIF, which display the effect of these phenomena and their relation to implosion asymmetry. This work was supported in part by the U.S. DOE, LLNL and LLE.

The role of colloids and suspended particles in radionuclide transport in the Canadian concept for nuclear fuel waste disposal

International Nuclear Information System (INIS)

Vilks, P.

1994-02-01

AECL Research is developing a concept for the permanent disposal of nuclear fuel waste in a deep engineered vault in plutonic rock of the Canadian Shield and is preparing an Environmental Impact Statement (EIS) to document its case for the acceptability of the disposal concept. This report, one in a series of supporting documents for the EIS, addresses the role of particles in radionuclide transport. It summarizes our studies of natural particles in groundwater and presents the arguments used to justify the omission of particle-facilitated transport in the geosphere model that is based on the Whiteshell Research Area (WRA) and used in the postclosure assessment study case. Because radiocolloids formed in the vault will not be able to migrate through the clay buffer, radiocolloid formation in the geosphere will be determined by the sorption of radionuclides onto particles in groundwater. These particles consist of typical fracture-lining minerals, such as clays, micas and quartz; precipitated particles, such as colloidal silica and Fe-Si oxyhydroxides; and organic particles. In groundwater from the WRA, the average concentrations of colloids and suspended particles are 0.34 and 1.4 mg/L respectively. Particle-facilitated transport is not included in the geosphere model because the concentrations of particles in groundwater from the WRA are too low to have a significant impact on radionuclide transport. (author). 92 refs., 11 tabs., 13 figs

Carbon conversion predictor for fluidized bed gasification of biomass fuels - from TGA measurements to char gasification particle model

Energy Technology Data Exchange (ETDEWEB)

Konttinen, J.T. [University of Jyvaeskylae, Department of Chemistry, Renewable Energy Programme, POB 35, Jyvaeskylae (Finland); Moilanen, A. [VTT Technical Research Centre of Finland, POB 1000, Espoo (Finland); Martini, N. de; Hupa, M. [Abo Akademi University, Process Chemistry Centre, Combustion and Materials Chemistry, Turku (Finland)

2012-09-15

When a solid fuel particle is injected into a hot fluidized bed, the reactivity of fuel char in gasification reactions (between char carbon and steam and CO{sub 2}) plays a significant role for reaching a good carbon conversion. In this paper, the gasification reactivity data of some solid waste recovered fuels (SRF) obtained from thermogravimetric analysis (TGA) experiments is presented. Gas mixtures (H{sub 2}O, H{sub 2}, CO{sub 2}, CO), were used in the experiments to find the inhibitive effects of CO and H{sub 2}. Average char gasification reactivity values are determined from the TGA results. Kinetic parameters for char carbon gasification reactivity correlations are determined from this data. The Uniform Conversion model is used to account for the change of gasification reaction rate as function of carbon conversion. Some discrepancies, due to complicated ash-carbon interactions, are subjects of further research. In the carbon conversion predictor, laboratory measured reactivity numbers are converted into carbon conversion numbers in a real-scale fluidized bed gasifier. The predictor is a relatively simple and transparent tool for the comparison of the gasification reactivity of different fuels in fluidized bed gasification. The residence times for solid fuels in fluidized bed gasifiers are simulated. Simulations against some pilot-scale results show reasonable agreement. (orig.)

Carbonate fuel cell matrix

Science.gov (United States)

Farooque, Mohammad; Yuh, Chao-Yi

1996-01-01

A carbonate fuel cell matrix comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles.

SILICON CARBIDE GRAIN BOUNDARY DISTRIBUTIONS, IRRADIATION CONDITIONS, AND SILVER RETENTION IN IRRADIATED AGR-1 TRISO FUEL PARTICLES

Energy Technology Data Exchange (ETDEWEB)

Lillo, T. M.; Rooyen, I. J.; Aguiar, J. A.

2016-11-01

Precession electron diffraction in the transmission electron microscope was used to map grain orientation and ultimately determine grain boundary misorientation angle distributions, relative fractions of grain boundary types (random high angle, low angle or coincident site lattice (CSL)-related boundaries) and the distributions of CSL-related grain boundaries in the SiC layer of irradiated TRISO-coated fuel particles. Two particles from the AGR-1 experiment exhibiting high Ag-110m retention (>80%) were compared to a particle exhibiting low Ag-110m retention (<19%). Irradiated particles with high Ag-110m retention exhibited a lower fraction of random, high angle grain boundaries compared to the low Ag-110m retention particle. An inverse relationship between the random, high angle grain boundary fraction and Ag-110m retention is found and is consistent with grain boundary percolation theory. Also, comparison of the grain boundary distributions with previously reported unirradiated grain boundary distributions, based on SEM-based EBSD for similarly fabricated particles, showed only small differences, i.e. a greater low angle grain boundary fraction in unirradiated SiC. It was, thus, concluded that SiC layers with grain boundary distributions susceptible to Ag-110m release were present prior to irradiation. Finally, irradiation parameters were found to have little effect on the association of fission product precipitates with specific grain boundary types.

Buses retrofitting with diesel particle filters: Real-world fuel economy and roadworthiness test considerations.

Science.gov (United States)

Fleischman, Rafael; Amiel, Ran; Czerwinski, Jan; Mayer, Andreas; Tartakovsky, Leonid

2018-05-01

Retrofitting older vehicles with diesel particulate filter (DPF) is a cost-effective measure to quickly and efficiently reduce particulate matter emissions. This study experimentally analyzes real-world performance of buses retrofitted with CRT DPFs. 18 in-use Euro III technology urban and intercity buses were investigated for a period of 12months. The influence of the DPF and of the vehicle natural aging on buses fuel economy are analyzed and discussed. While the effect of natural deterioration is about 1.2%-1.3%, DPF contribution to fuel economy penalty is found to be 0.6% to 1.8%, depending on the bus type. DPF filtration efficiency is analyzed throughout the study and found to be in average 96% in the size range of 23-560nm. Four different load and non-load engine operating modes are investigated on their appropriateness for roadworthiness tests. High idle is found to be the most suitable regime for PN diagnostics considering particle number filtration efficiency. Copyright © 2017. Published by Elsevier B.V.

The calculation - experimental investigations of the HTGR fuel element construction

International Nuclear Information System (INIS)

Eremeev, V.S.; Kolesov, V.S.; Chernikov, A.S.

1985-01-01

One of the most important problems in the HTGR development is the creation of the fuel element gas-tight for the fission products. This problem is being solved by using fuel elements of dispersion type representing an ensemble of coated fuel particles dispersed in the graphite matrix. Gas-tightness of such fuel elements is reached at the expense of deposing a protective coating on the fuel particles. It is composed of some layers serving as diffusion barriers for fission products. It is apparent that the rate of fission products diffusion from coated fuel particles is determined by the strength and temperature of the protective coating

Status of LEU fuel development and conversion of NRU

International Nuclear Information System (INIS)

Sears, D.F.; Herbert, L.N.; Vaillancourt, K.D.

1989-11-01

The status of the low-enrichment uranium (LEU) fuel development and NRU conversion program at Chalk River Nuclear Laboratories is reviewed. Construction of a new fuel fabrication facility is essentially completed and installation of LEW fuel manufacturing equipment has begun. The irradiation of 31 prototype Al-61 wt% U 3 Si dispersion fuel rods, approximately one third of a full NRU core, is continuing without incident. Recent post-irradiation examination of spent fuel rods revealed that the prototype LEU fuel achieved the design burnup (80 at%) in excellent condition, confirming that the Al-U 3 Si 2 dispersion fuel to complement out Al-U 3 Si capability. Three full-size NRU rods containing Al-U 3 Si 2 dispersion fuel have been fabricated for a qualification irradiation in NRU. Post-irradiation examinations of mini-elements containing Al-U 3 Si 2 fuel revealed that the U 3 Si 2 behaved similarly to U 3 Si 2 fuel revealed that the U 3 Si 2 particles and the aluminum matrix, and fission gas bubbles up to 10 μm in diameter, could be seen in the particles after 60 at% and 80 at% burnup. The mini-elements contained a variety of silicide particle sizes; however, no significant swelling dependence on particle size distribution was observed

High Temperature Gas Cooled Reactor Fuels and Materials

International Nuclear Information System (INIS)

2010-03-01

At the third annual meeting of the technical working group on Nuclear Fuel Cycle Options and Spent Fuel Management (TWG-NFCO), held in Vienna, in 2004, it was suggested 'to develop manuals/handbooks and best practice documents for use in training and education in coated particle fuel technology' in the IAEA's Programme for the year 2006-2007. In the context of supporting interested Member States, the activity to develop a handbook for use in the 'education and training' of a new generation of scientists and engineers on coated particle fuel technology was undertaken. To make aware of the role of nuclear science education and training in all Member States to enhance their capacity to develop innovative technologies for sustainable nuclear energy is of paramount importance to the IAEA Significant efforts are underway in several Member States to develop high temperature gas cooled reactors (HTGR) based on either pebble bed or prismatic designs. All these reactors are primarily fuelled by TRISO (tri iso-structural) coated particles. The aim however is to build future nuclear fuel cycles in concert with the aim of the Generation IV International Forum and includes nuclear reactor applications for process heat, hydrogen production and electricity generation. Moreover, developmental work is ongoing and focuses on the burning of weapon-grade plutonium including civil plutonium and other transuranic elements using the 'deep-burn concept' or 'inert matrix fuels', especially in HTGR systems in the form of coated particle fuels. The document will serve as the primary resource materials for 'education and training' in the area of advanced fuels forming the building blocks for future development in the interested Member States. This document broadly covers several aspects of coated particle fuel technology, namely: manufacture of coated particles, compacts and elements; design-basis; quality assurance/quality control and characterization techniques; fuel irradiations; fuel

Emissions from Ethanol-Gasoline Blends: A Single Particle Perspective

Directory of Open Access Journals (Sweden)

Peter H. McMurry

2011-06-01

Full Text Available Due to its agricultural origin and function as a fuel oxygenate, ethanol is being promoted as an alternative biomass-based fuel for use in spark ignition engines, with mandates for its use at state and regional levels. While it has been established that the addition of ethanol to a fuel reduces the particulate mass concentration in the exhaust, little attention has been paid to changes in the physicochemical properties of the emitted particles. In this work, a dynamometer-mounted GM Quad-4 spark ignition engine run without aftertreatment at 1,500 RPM and 100% load was used with four different fuel blends, containing 0, 20, 40 and 85 percent ethanol in gasoline. This allowed the effects of the fuel composition to be isolated from other effects. Instrumentation employed included two Aerosol Time-of-Flight Mass Spectrometers covering different size ranges for analysis of single particle composition, an Aethalometer for black carbon, a Scanning Mobility Particle Sizer for particle size distributions, a Photoelectric Aerosol Sensor for particle-bound polycyclic aromatic hydrocarbon (PAH species and gravimetric filter measurements for particulate mass concentrations. It was found that, under the conditions investigated here, additional ethanol content in the fuel changes the particle size distribution, especially in the accumulation mode, and decreases the black carbon and total particulate mass concentrations. The molecular weight distribution of the PAHs was found to decrease with added ethanol. However, PAHs produced from higher ethanol-content fuels are associated with NO2− (m/z—46 in the single-particle mass spectra, indicating the presence of nitro-PAHs. Compounds associated with the gasoline (e.g., sulfur-containing species are diminished due to dilution as ethanol is added to the fuel relative to those associated with the lubricating oil (e.g., calcium, zinc, phosphate in the single particle spectra. These changes have potential

Effect of Fuel Additives on Spray Performance of Alternative Jet Fuels

Science.gov (United States)

Kannaiyan, Kumaran; Sadr, Reza

2015-11-01

Role of alternative fuels on reducing the combustion pollutants is gaining momentum in both land and air transport. Recent studies have shown that addition of nanoscale metal particles as fuel additives to liquid fuels have a positive effect not only on their combustion performance but also in reducing the pollutant formation. However, most of those studies are still in the early stages of investigation with the addition of nanoparticles at low weight percentages. Such an addition can affect the hydrodynamic and thermo-physical properties of the fuel. In this study, the near nozzle spray performance of gas-to-liquid jet fuel with and without the addition of alumina nanoparticles are investigated at macro- and microscopic levels using optical diagnostic techniques. At macroscopic level, the addition of nanoparticles is seen to enhance the sheet breakup process when compared to that of the base fuel. Furthermore, the microscopic spray characteristics such as droplet size and velocity are also found to be affected. Although the addition of nanoscale metal particles at low weight percentages does not affect the bulk fluid properties, the atomization process is found to be affected in the near nozzle region. Funded by Qatar National Research Fund.

Processing of FRG mixed oxide fuel elements at General Atomic under the US/FRG cooperative agreement for spent fuel elements

International Nuclear Information System (INIS)

Holder, N.D.; Strand, J.B.; Schwarz, F.A.; Tischer, H.E.

1980-11-01

The Federal Republic of Germany (FRG) and the United States (US) are cooperating on certain aspects gas-cooled reactor technology under an umbrella agreement. Under the spent fuel treatment section of the agreement, FRG fuel spheres were recently sent for processing in the Department of Energy sponsored cold pilot plant for High-Temperature Gas-Cooled Reactor (HTGR) fuel processing at General Atomic Company in San Diego, California. The FRG fuel spheres were crushed and burned to recover coated fuel particles. These particles were in turn crushed and burned to recover the fuel-bearing kernels for further treatment for uranium recovery. Successful completion of the tests described in this paper demonstrated the applicability of the US HTGR fuel treatment flowsheet to FRG fuel processing. 10 figures

Confined dense particle-gas flow, application to nuclear fuel relocation

International Nuclear Information System (INIS)

Martin, A.

2010-02-01

In this work, we investigate particle-gas two-phase flows in the jamming regime where the flow stops in finite time. In this regime, which occurs quite often in nature and industrial applications, the flow is stochastic and needs therefore to be characterized by the jamming probability as well as the flow rate and its fluctuations that depend on the confining geometry, granular microstructure and gas properties. We developed a numerical approach based on the coupling of the Non Smooth Contact Dynamics for the solid phase and a mesoscopic method for the gas phase. We find that the flow rate as a function of the opening is well fit by a power law in agreement with reported experimental data. The presence of a gas affects only the mean flow rate, the flow statistics being sensibly the same as in the absence of the gas. We apply our quantitative statistical results in order to estimate the relocation rate of fragmented nuclear fuel inside its cladding tube as a result of a local balloon caused by an accident (loss-of-coolant accident). (author)

Grooved Fuel Rings for Nuclear Thermal Rocket Engines

Science.gov (United States)

Emrich, William

2009-01-01

An alternative design concept for nuclear thermal rocket engines for interplanetary spacecraft calls for the use of grooved-ring fuel elements. Beyond spacecraft rocket engines, this concept also has potential for the design of terrestrial and spacecraft nuclear electric-power plants. The grooved ring fuel design attempts to retain the best features of the particle bed fuel element while eliminating most of its design deficiencies. In the grooved ring design, the hydrogen propellant enters the fuel element in a manner similar to that of the Particle Bed Reactor (PBR) fuel element.

Experimental investigation of particulate emissions from a diesel engine fueled with ultralow-sulfur diesel fuel blended with diglyme

Science.gov (United States)

Di, Yage; Cheung, C. S.; Huang, Zuohua

2010-01-01

Experiments are conducted on a 4-cylinder direct-injection diesel engine using ultralow-sulfur diesel as the base fuel and diglyme as the oxygenate component to investigate the particulate emissions of the engine under five engine loads at two engine speeds of 1800 rev min -1 and 2400 rev min -1. Blended fuels containing 5%, 10.1%, 15.2%, 20.4%, 25.7% and 53% by volume of diglyme, corresponding to 2%, 4%, 6%, 8%, 10% and 20% by mass of oxygen, are studied. The study shows that with the increase of oxygen in the fuel blends, smoke opacity, particulate mass concentration, NO x concentration and brake specific particulate emission are reduced at the two engine speeds. However, the proportion of soluble organic fraction is increased. For each blended fuel, the total particle number concentration is higher while the geometric mean diameter is smaller, compared with that of ultralow-sulfur diesel, though the particle number decreases with the oxygen content of the blended fuel. Furthermore, the blended fuels also increase the number concentrations of particles smaller than 100 nm.

Comparative study of random and uniform models for the distribution of TRISO particles in HTR-10 fuel elements

International Nuclear Information System (INIS)

Rosales, J.; Perez, J.; Garcia, C.; Munnoz, A.; Lira, C. A. B. O.

2015-01-01

TRISO particles are the specific features of HTR-10 and generally HTGR reactors. Their heterogeneity and random arrangement in graphite matrix of these reactors create a significant modeling challenge. In the simulation of spherical fuel elements using MCNPX are usually created repetitive structures using uniform distribution models. The use of these repetitive structures introduces two major approaches: the non-randomness of the TRISO particles inside the pebbles and the intersection of the pebble surface with the TRISO particles. These approaches could affect significantly the multiplicative properties of the core. In order to study the influence of these approaches in the multiplicative properties was estimated the K inf value in one pebble with white boundary conditions using 4 different configurations regarding the distribution of the TRISO particles inside the pebble: uniform hexagonal model, cubic uniform model, cubic uniform without the effect of cutting and a random distribution model. It was studied the impact these models on core scale solving the problem B1, from the Benchmark Problems presented in a Coordinated Research Program of the IAEA. (Author)

Characterization of fuel miniplates fabricated with U(Mo) particles dispersed in Al-Si matrices

International Nuclear Information System (INIS)

Arico, S F; Mirandou, M I; Balart, S N; Fabro, J O

2012-01-01

In 2011 ECRI facility (Depto. ECRI, GCCN, CNEA) restarted the development for the fabrication of dispersion miniplates fuel elements in Al-Si matrix. This miniplates are fabricated with atomized U-7wt%Mo particles dispersed in a matrix formed by a mixture of pure Al and pure Si powders. The first results for an Al-4wt%Si matrix were presented at the AATN 2011 Annual Meeting. In this work, new results from the microstructural characterization of the meat in Al- 2wt%Si and pure Al miniplates are presented and compared with the previous ones. It is the intention to study the influence of the fabrication parameters as well as different Si concentration in the matrix, on the formation and characteristics of the interaction layer formed between the particles and the matrix at the end of the fabrication process. According to the results presented in this work an improvement can be observed on miniplates with Al-Si matrix respect to the one with pure Al. On the miniplates with Al- Si matrix, almost 100 % of the U(Mo) particles presented, at least in some fraction of its surface, an interaction layer composed by phases that contain Si. Moreover its morphological characteristics are independent of the crystallographic state of the U(Mo) particles. However, the oxide layer formed on the U(Mo) during the hot rolling acts as a barrier to the formation of the interaction layer. As a consequence, it is then mandatory to introduce some changes on the fabrication parameters to avoid, or at least minimize, this oxide layer (author)

Gas-fueling studies in the PDX tokamak

International Nuclear Information System (INIS)

Dylla, H.F.; Blanchard, W.R.; Budny, R.; Fonck, R.J.; Owens, D.K.; Schmidt, G.L.

1982-08-01

The characteristics of gas-fueling of high power discharges in the PDX tokamak have been investigated using gas-flow, neutral pressure, plasma density, and Hα emission measurements. The efficiency of gas-fueling was measured for various plasma configurations by comparison of the measured gas-influx rates to the particle exhaust rates inferred from particle decay time measurements. We observe that the fueling efficiency decreases significantly with increasing plasma density as the ionization length for thermal neutrals becomes shorter than the width of the boundary plasma. Gas fueling rates required to maintain a given plasma density are considerably higher (by factors of 5 to 10) for diverted discharges compared to limiter discharges. This result is attributed to a lower effective recycling coefficient for diverted plasmas. We discuss the dependence of the particle balance on the following experimentally measured parameters: the particle containment time, system-pumping speed, and neutral pressure in the vicinity of the active pumps

The Influence of Particle Size, Fluidization Velocity, and Fuel Type on Ash-Induced Agglomeration in Biomass Combustion

Energy Technology Data Exchange (ETDEWEB)

Gatternig, Bernhard, E-mail: bernhard.gatternig@cbi.uni-erlangen.de; Karl, Jürgen [Chair of Energy Process Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Nuremberg (Germany)

2014-11-19

Agglomeration of the bed material is one of the main obstacles for biomass utilization in fluidized bed combustors. Especially, high-potential fuels such as fast growing energy crops or biogeneous residues are affected because of their high content of alkaline metals. Despite ongoing research efforts, the knowledge base on what fuels are affected is still limited. This paper describes the design and installation of two lab-scale reactors for the experimental determination of agglomeration temperatures. The reactor concept and measurement method were developed under consideration of experiences from existing test rigs published in literature. Preliminary tests confirmed a reproducibility of ±5°C for both new reactors. The results of an extended measurement campaign (156 test runs of 25 fuel species at a wide range of the operational parameters “bed particle size,” “gas velocity,” and “bed ash accumulation”), based on “design of experiment” (DoE) criteria, showed high-agglomeration tendencies for residues (e.g., dried distillery grains, corn cobs) while woody energy crops (e.g., willow, alder) exhibited very stable combustion behavior. The operating parameters influenced the agglomeration behavior to a lesser degree than different ash compositions of fuel species tested. An interpolation within the DoE factor space allowed for a subsequent comparison of our results with experiments reported in literature. Good agreement was reached for fuels of comparable ash composition considering the interpolation errors of ±32°C on average.

Tests of candidate materials for particle bed reactors

International Nuclear Information System (INIS)

Horn, F.L.; Powell, J.R.; Wales, D.

1987-01-01

Rhenium metal hot frits and zirconium carbide-coated fuel particles appear suitable for use in flowing hydrogen to at least 2000 K, based on previous tests. Recent tests on alternate candidate cooled particle and frit materials are described. Silicon carbide-coated particles began to react with rhenium frit material at 1600 K, forming a molten silicide at 2000 K. Silicon carbide was extensively attacked by hydrogen at 2066 K for 30 minutes, losing 3.25% of its weight. Vitrous carbon was also rapidly attacked by hydrogen at 2123 K, losing 10% of its weight in two minutes. Long term material tests on candidate materials for closed cycle helium cooled particle bed fuel elements are also described. Surface imperfections were found on the surface of pyrocarbon-coated fuel particles after ninety days exposure to flowing (∼500 ppM) impure helium at 1143 K. The imperfections were superficial and did not affect particle strength

Modeling random combustion of lycopodium particles and gas

Directory of Open Access Journals (Sweden)

M Bidabadi

2016-06-01

Full Text Available The random modeling combustion of lycopodium particles has been researched by many authors. In this paper, we extend this model and we also generate a different method by analyzing the effect of random distributed sources of combustible mixture. The flame structure is assumed to consist of a preheat-vaporization zone, a reaction zone and finally a post flame zone. We divide the preheat zone to different parts. We assumed that there is different distribution of particles in sections which are really random. Meanwhile, it is presumed that the fuel particles vaporize first to yield gaseous fuel. In other words, most of the fuel particles are vaporized at the end of the preheat zone. It is assumed that the Zel’dovich number is large; therefore, the reaction term in preheat zone is negligible. In this work, the effect of random distribution of particles in the preheat zone on combustion characteristics such as burning velocity, flame temperature for different particle radius is obtained.

Thermal-hydraulic analysis of an annular fuel element: The Achilles' heel of the particle bed reactor

International Nuclear Information System (INIS)

Dibben, M.J.; Tuttle, R.F.

1993-01-01

The low pressure nuclear thermal propulsion (LPNTP) concept offers significant improvements in rocket engine specific impulse over rockets employment chemical propulsion. This study investigated a parametric thermal-hydraulic analysis of an annular fueld element, also referred to as a fuel pipe, using the computer code ATHENA (Advanced Thermal Hydraulic Energy Network Analyzer). The fuelpipe is an annular particle bed fuel element of the reactor with radially inward flow of hydrogen through the element. In this study, the outlet temperature of the hydrogen is parametrically related to key effects, including the reactor power at two different pressure drops, the effect of power coupling for in-core testing, and the effect of hydrogen flow rates. Results show that the temperature is linearly related to the reactor power, but not to pressure drop, and that cross flow inside the fuelpipe occurs at approximately 0.3 percent of the radial flow rates

Mechanistic study of fuel freezing, channel plugging, and continued coolability during fast reactor overpower excursions

International Nuclear Information System (INIS)

Wong, K.W.; Catton, I.; Kastenberg, W.E.

1977-07-01

A mechanistic model is presented which describes events following fuel pin failure which may lead to in-channel fuel plate-out. The thermal and hydraulic effects of the plate-out fuel are also evaluated. Given the amount and particle size of the fuel injected into the coolant channel during fuel pin failure, and the initial conditions of the interaction zone, the physical states of the fuel particles and the coolant in the interaction zone can be determined. The trajectories of the fuel particles in the coolant channel are determined by assuming a slip factor between the local tangential velocities of the coolant and the fuel particles. The time and distance after which a fuel particle hits a wire wrap are then determined and the impact stresses induced in the thin solid fuel crust can be evaluated

Radiation resistance of pyrocarbon-boned fuel and absorbing elements for HTGR

International Nuclear Information System (INIS)

Gurin, V.A.; Konotop, Yu.F.; Odejchuk, N.P.; Shirochenkov, S.D.; Yakovlev, V.K.; Aksenov, N.A.; Kuprienko, V.A.; Lebedev, I.G.; Samsonov, B.V.

1990-01-01

In choosing the reactor type, problems of nuclear and radiation safety are outstanding. The analysis of the design and experiments show that HTGR type reactors helium cooled satisfy all the safety requirements. It has been planned in the Soviet Union to construct two HTGR plants, VGR-50 and VG-400. Later it was decided to construct an experimental plant with a low power high temperature reactor (VGM). Spherical uranium-graphite fuel elements with coated fuel particles are supposed to be used in HTGR core. A unique technology for producing spherical pyrocarbon-bound fuel and absorbing elements of monolithic type has been developed. Extended tests were done to to investigate fuel elements behaviour: radiation resistance of coated fuel particles with different types of fuel; influence of the coated fuel particles design on gaseous fission products release; influence of non-sphericity on coated fuel particle performance; dependence of gaseous fission products release from fuel elements on the thickness of fuel-free cans; confining role of pyrocarbon as a factor capable of diminishing the rate of fission products release; radiation resistance of spherical fuel elements during burnup; radiation resistance of spherical absorbing elements to fast neutron fluence and boron burnup

Effect of 3-D magnetic fields on neutral particle fueling and exhaust in MAST

Science.gov (United States)

Flesch, Kurt; Kremeyer, Thierry; Waters, Ian; Schmitz, Oliver; Kirk, Andrew; Harrison, James

2017-10-01

The application of resonant magnetic perturbations (RMPs) is used to suppress edge localized modes but causes in many cases a density pump-out. At MAST, this particle pump out was found to be connected to an amplifying MHD plasma response. An analysis is presented on past MAST discharges to understand the effect of these RMPs on the neutral household and on changes in neutral fueling and exhaust during the pump out. A global, 0-D particle balance model was used to study the neutral dynamics and plasma confinement during shots with and without RMP application. Using the D α emission measured by filterscopes and a calibrated 1-D CCD camera, as well as S/XB coefficients determined by the edge plasma parameters, globally averaged ion confinement times were calculated. In L-mode, discharges with RMPs that caused an MHD response had a 15-20% decrease in confinement time but an increase in total recycling flux. The application of RMPs in H-mode caused either a decrease or no change in confinement, like those in L-mode, depending on the configuration of the RMPs and plasma response. A spectroscopically assisted Penning gauge is being prepared for the next campaign at MAST-U to extend this particle balance to study impurity exhaust with RMPs. This work was funded in part by the U.S. DoE under Grant DE-SC0012315.

Modelling of U-Mo/Al Dispersion fuel fission induced swelling and creep

Energy Technology Data Exchange (ETDEWEB)

Jeong, Gwan Yoon; Sohn, Dong Seong [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); Kim, Yeon Soo [Argonne National Laboratory, Argonne (United States)

2014-05-15

In a Dispersion fuel which U-Mo particles are dispersed in Al metal matrix, a similar phenomenon forming a bulge region was observed but it is difficult to quantify and construct a model for explaining creep and swelling because of its complex microstructure change during irradiation including interaction layer (IL) and porosity formation. In a Dispersion fuel meat, fission product induces fuel particles swelling and it has to be accommodated by the deformation of the Al matrix and newly formed IL during irradiation. Then, it is reasonable that stress from fuel swelling in the complex structure should be relaxed by local adjustments of particles, Al matrix, and IL. For analysis of U-Mo/Al Dispersion fuel creep, the creep of U-Mo particle, Al matrix, and IL should be considered. Moreover, not only fuel particle swelling and IL growth, but also fuel and Al matrix consumptions due to IL formation are accounted in terms of their volume fraction changes during irradiation. In this work, fuel particles, Al matrix and IL are treated in a way of homogenized constituents: Fuel particles, Al matrix and IL consist of an equivalent meat during irradiation. Meat volume swelling of two representative plates was measured: One (Plate A) was a pure Al matrix with 6g/cc uranium loading, the other (Plate B) a silicon added Al matrix with 8g/cc uranium loading. The meat swelling of calculated as a function of burnup. The meat swelling of calculation and measurement was compared and the creep rate coefficients for Al and IL were estimated by repetitions. Based on assumption that only the continuous phase of Al-IL combined matrix accommodated the stress from fuel particle swelling and it was allowed to have creep deformation, the homogenization modeling was performed. The meat swelling of two U-Mo/Al Dispersion fuel plates was modeled by using homogenization model.

Modelling of U-Mo/Al Dispersion fuel fission induced swelling and creep

International Nuclear Information System (INIS)

Jeong, Gwan Yoon; Sohn, Dong Seong; Kim, Yeon Soo

2014-01-01

In a Dispersion fuel which U-Mo particles are dispersed in Al metal matrix, a similar phenomenon forming a bulge region was observed but it is difficult to quantify and construct a model for explaining creep and swelling because of its complex microstructure change during irradiation including interaction layer (IL) and porosity formation. In a Dispersion fuel meat, fission product induces fuel particles swelling and it has to be accommodated by the deformation of the Al matrix and newly formed IL during irradiation. Then, it is reasonable that stress from fuel swelling in the complex structure should be relaxed by local adjustments of particles, Al matrix, and IL. For analysis of U-Mo/Al Dispersion fuel creep, the creep of U-Mo particle, Al matrix, and IL should be considered. Moreover, not only fuel particle swelling and IL growth, but also fuel and Al matrix consumptions due to IL formation are accounted in terms of their volume fraction changes during irradiation. In this work, fuel particles, Al matrix and IL are treated in a way of homogenized constituents: Fuel particles, Al matrix and IL consist of an equivalent meat during irradiation. Meat volume swelling of two representative plates was measured: One (Plate A) was a pure Al matrix with 6g/cc uranium loading, the other (Plate B) a silicon added Al matrix with 8g/cc uranium loading. The meat swelling of calculated as a function of burnup. The meat swelling of calculation and measurement was compared and the creep rate coefficients for Al and IL were estimated by repetitions. Based on assumption that only the continuous phase of Al-IL combined matrix accommodated the stress from fuel particle swelling and it was allowed to have creep deformation, the homogenization modeling was performed. The meat swelling of two U-Mo/Al Dispersion fuel plates was modeled by using homogenization model

Thermal Conductivity Measurement and Analysis of Fully Ceramic Microencapsulated fuel

International Nuclear Information System (INIS)

Lee, H. G.; Kim, D. J.; Park, J. Y.; Kim, W. J.; Lee, S. J.

2015-01-01

FCM nuclear fuel is composed of tristructural isotropic(TRISO) fuel particle and SiC ceramic matrix. SiC ceramic matrix play an essential part in protecting fission product. In the FCM fuel concept, fission product is doubly protected by TRISO coating layer and SiC ceramic matrix in comparison with the current commercial UO2 fuel system of LWR. In addition to a safety enhancement of FCM fuel, thermal conductivity of SiC ceramic matrix is better than that of UO2 fuel. Because the centerline temperature of FCM fuel is lower than that of the current UO2 fuel due to the difference of thermal conductivity of fuel, an operational release of fission products from the fuel can be reduced. SiC ceramic has attracted for nuclear fuel application due to its high thermal conductivity properties with good radiation tolerant properties, a low neutron absorption cross-section and a high corrosion resistance. Thermal conductivity of ceramic matrix composite depends on the thermal conductivity of each component and the morphology of reinforcement materials such as fibers and particles. There are many results about thermal conductivity of fiber-reinforced composite like as SiCf/SiC composite. Thermal conductivity of SiC ceramics and FCM pellets with the volume fraction of TRISO particles were measured and analyzed by analytical models. Polycrystalline SiC ceramics and FCM pellets with TRISO particles were fabricated by hot press sintering with sintering additives. Thermal conductivity of the FCM pellets with TRISO particles of 0 vol.%, 10 vol.%, 20 vol.%, 30 vol.% and 40 vol.% show 68.4, 52.3, 46.8, 43.0 and 34.5 W/mK, respectively. As the volume fraction of TRISO particles increased, the measured thermal conductivity values closely followed the prediction of Maxwell's equation

Quantitative chemical method for the determination of the disordered carbon component in pyrocarbon coatings of fuel particles

International Nuclear Information System (INIS)

Wolfrum, E.A.; Nickel, H.

1977-01-01

The chemical behavior of the surface of pyrocarbon (PyC) coatings of nuclear fuel particles was investigated in aqueous suspension by reaction with oxygen at room temperature. The concentration of the disordered material component, which has a large internal surface, can be identified by means of a pH change. Using this fact, a chemical method was developed that can be used for the quantitative determination of the concentration of this carbon component in the PyC coating

The particle size distribution of fragmented melt debris from molten fuel coolant interactions

International Nuclear Information System (INIS)

Fletcher, D.F.

1984-04-01

Results are presented of a study of the types of statistical distributions which arise when examining debris from Molten Fuel Coolant Interactions. The lognormal probability distribution and the modifications of this distribution which result from the mixing of two distributions or the removal of some debris are described. Methods of fitting these distributions to real data are detailed. A two stage fragmentation model has been developed in an attempt to distinguish between the debris produced by coarse mixing and fine scale fragmentation. However, attempts to fit this model to real data have proved unsuccessful. It was found that the debris particle size distributions from experiments at Winfrith with thermite generated uranium dioxide/molybdenum melts were Upper Limit Lognormal. (U.K.)

Metal Matrix Microencapsulated Fuel Technology for LWR Applications

International Nuclear Information System (INIS)

Terrani, Kurt A.; Bell, Gary L.; Kiggans, Jim; Snead, Lance Lewis

2012-01-01

An overview of the metal matrix microencapsulated (M3) fuel concept for the specific LWR application has been provided. Basic fuel properties and characteristics that aim to improve operational reliability, enlarge performance envelope, and enhance safety margins under design-basis accident scenarios are summarized. Fabrication of M3 rodlets with various coated fuel particles over a temperature range of 800-1300 C is discussed. Results from preliminary irradiation testing of LWR M3 rodlets with surrogate coated fuel particles are also reported.

In-pile irradiation of rock-like oxide fuels

International Nuclear Information System (INIS)

Nitani, N.; Kuramoto, K.; Yamashita, T.; Nakano, Y.; Akie, H.

2001-01-01

Five kinds of ROX fuels were prepared and irradiated using 20% enriched U instead of Pu. Non-destructive and destructive post-irradiation examinations were carried out. FP gas release rates of the particle-dispersed type fuels and homogeneously-blended type fuels were larger than that of the Yttria-stabilized zirconia containing UO 2 single phase fuel. From results of SEM and EPMA, decomposition of the spinel was observed. The decomposition of the spinel is probably avoided by lowering the irradiation temperature, less than 1700 K. The regions suffering the irradiation damage of the particle dispersed type fuels were less than those of the homogeneously-blended type fuels. (author)

In-pile irradiation of rock-like oxide fuels

Energy Technology Data Exchange (ETDEWEB)

Nitani, N.; Kuramoto, K.; Yamashita, T.; Nakano, Y.; Akie, H. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)

2001-07-01

Five kinds of ROX fuels were prepared and irradiated using 20% enriched U instead of Pu. Non-destructive and destructive post-irradiation examinations were carried out. FP gas release rates of the particle-dispersed type fuels and homogeneously-blended type fuels were larger than that of the Yttria-stabilized zirconia containing UO{sub 2} single phase fuel. From results of SEM and EPMA, decomposition of the spinel was observed. The decomposition of the spinel is probably avoided by lowering the irradiation temperature, less than 1700 K. The regions suffering the irradiation damage of the particle dispersed type fuels were less than those of the homogeneously-blended type fuels. (author)

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

Improvements in quality of as-manufactured fuels for high-temperature gas-cooled reactors

International Nuclear Information System (INIS)

Minato, Kazuo; Kikuchi, Hironobu; Tobita, Tsutomu; Fukuda, Kousaku; Kaneko, Mitsunobu; Suzuki, Nobuyuki; Yoshimuta, Shigeharu; Tomimoto, Hiroshi.

1997-01-01

The mechanisms of coating failure of the fuel particles for the high-temperature gas-cooled reactors during coating and compaction processes of the fuel fabrication were studied to determine a way to reduce the defective particle fraction of the as-manufactured fuels. Through the observation of the defective particles, it was found that the coating failure during the coating process was mainly caused by the strong mechanical shocks to the particles given by violent particle fluidization in the coater and by unloading and loading of the particles. The coating failure during the compaction process was probably related to the direct contact with neighboring particles in the fuel compacts. The coating process was improved by optimizing the mode of the particle fluidization and by developing the process without unloading and loading of the particles at intermediate coating process. The compaction process was improved by optimizing the combination of the pressing temperature and the pressing speed of the overcoated particles. Through these modifications of the fabrication process, the quality of the as-manufactured fuel compacts was improved outstandingly. (author)

Intermittent contact of fluidized anode particles containing exoelectrogenic biofilms for continuous power generation in microbial fuel cells

KAUST Repository

Liu, Jia

2014-09-01

Current generation in a microbial fuel cell can be limited by the amount of anode surface area available for biofilm formation, and slow substrate degradation kinetics. Increasing the anode surface area can increase the amount of biofilm, but performance will improve only if the anode material is located near the cathode to minimize solution internal resistance. Here we demonstrate that biofilms do not have to be in constant contact with the anode to produce current in an MFC. Granular activated carbon particles enriched with exoelectrogenic biofilm are fluidized (by stirring) in the anode chamber of the MFC, resulting in only intermittent contact between the particles and the anode current collector. The maximum power density generated is 951 ± 10 mW m-2, compared to 813 ± 2 mW m-2 for the control without stirring (packed bed), and 525 ± 1 mW m-2 in the absence of GAC particles and without stirring. GAC-biofilm particles demonstrate capacitor-like behavior, but achieve nearly constant discharge conditions due to the large number of particles that contact the current collector. These results provide proof of concept for the development of flowable electrode reactors, where anode biofilms can be electrically charged in a separate storage tank and then rapidly discharged in compact anode chambers. © 2014 Elsevier B.V. All rights reserved.

Intermittent contact of fluidized anode particles containing exoelectrogenic biofilms for continuous power generation in microbial fuel cells

KAUST Repository

Liu, Jia; Zhang, Fang; He, Weihua; Zhang, Xiaoyuan; Feng, Yujie; Logan, Bruce E.

2014-01-01

Current generation in a microbial fuel cell can be limited by the amount of anode surface area available for biofilm formation, and slow substrate degradation kinetics. Increasing the anode surface area can increase the amount of biofilm, but performance will improve only if the anode material is located near the cathode to minimize solution internal resistance. Here we demonstrate that biofilms do not have to be in constant contact with the anode to produce current in an MFC. Granular activated carbon particles enriched with exoelectrogenic biofilm are fluidized (by stirring) in the anode chamber of the MFC, resulting in only intermittent contact between the particles and the anode current collector. The maximum power density generated is 951 ± 10 mW m-2, compared to 813 ± 2 mW m-2 for the control without stirring (packed bed), and 525 ± 1 mW m-2 in the absence of GAC particles and without stirring. GAC-biofilm particles demonstrate capacitor-like behavior, but achieve nearly constant discharge conditions due to the large number of particles that contact the current collector. These results provide proof of concept for the development of flowable electrode reactors, where anode biofilms can be electrically charged in a separate storage tank and then rapidly discharged in compact anode chambers. © 2014 Elsevier B.V. All rights reserved.

Plasma flow driven by fusion-generated alpha particles

International Nuclear Information System (INIS)

Ikuta, Kazunari.

1978-05-01

The confinement of fusion-generated alpha particles will affect the transports of the background plasma particles by the momentum transfer from the energetic alphas. The ions tend to migrate towards the center of plasma (i.e. fuel injection) and electrons towards the plasma periphery. This means the existence of a mechanism which enable to pump out the ashes in the fuel plasma because of the momentum conservation of whole plasma particles. (author)

A study on the basic CVD process technology for TRISO coated particle fuel

International Nuclear Information System (INIS)

Choi, D. J.; Cheon, J. H.; Keum, I. S.; Lee, H. S.; Kim, J. G.

2006-03-01

Hydrogen energy has many advantages and is suitable as alternative energy of fossil fuel. The study of nuclear hydrogen production has performed at present. For nuclear hydrogen production, it is needed the study of VHTR(Very High Temperature Reactor) and TRISO(TRI-iSOtropic) coated fuel. TRISO coated fuel particle deposited by FBCVD(Fludized Bed CVD) method is composed of three isotropic layers: Inner Pyrolytic Carbon (IPyC), Silicon Carbide (SiC), Outer Pyrolytic Carbon (OPyC) layers. Silicon carbide was chemically vapor deposed on graphite substrate using methyltrichlorosilane (CH 3 SiCl 3 ) as a source in hydrogen atmosphere. The effect of deposition temperature and input gas ratios ( α=Q H2 /Q MTS =P H2 /P MTS ) was investigated in order to find out characteristics of silicon carbide layer. From results of those, SiC-TRISO coating deposition was conducted and achieved. Zirconium carbide layer as an advanced material of silicon carbide layer has studied. In order to find out basic properties and characteristics, studies have conducted using various methods. Zirconium carbide is chemically vapor deposed subliming zirconium tetrachloride(ZrCl 4 ) and using methan(CH 4 ) as a source in hydrogen atmosphere. Many experiments were conducted on graphite substrate about many deposition conditions such as ZrCl 4 heating temperatures and variables of H2 and CH 4 flow rate. but carbon graphite was deposited. For deposition of zirconium carbide, several different methods were approached. so zirconium carbide deposed on ZrO 2 substrate. In this experiments. source subliming type and equipment are no problems. But deposition of zirconium carbide will be continuously studied on graphite substrate approaching views of experimental way and equipment structure

Bimetallic Ag–Ni/C particles as cathode catalyst in AFCs (alkaline fuel cells)

International Nuclear Information System (INIS)

Song, Xingjuan; Zhang, Dongming

2014-01-01

AFCs (alkaline fuel cells) is one of the promising fuel cells, due to their low working temperature and less corrosive environment. However, decreasing the catalyst cost and improving its performance are still the challenges in its application. Transition metal as the catalyst for AFCs not only can reduce its cost, but also has great electro-catalytic efficiency. In this paper, Carbon supported Ag–Ni bimetallic catalysts with differential Ag/Ni atomic ratios were prepared by chemically reducing silver and nickel salts. Ag 3 Ni/C shows the relatively higher ORR (oxygen reduction reaction) activity among the differential Ag/Ni bimetallic particles. In order to improve the activity and stability, the catalysts were heat-treated at the temperature of 500 °C. The results indicate that the limiting current density has been improved greatly for Ag 3 Ni/C-500 °C, which is as high as 2.5× that of Ag/C. The microstructure investigation show that the non-equilibrium state of Ag–Ni alloy by heat treatment is confirmed by HRTEM (high-resolution transmission electron microscopy) images, and Ag(111) surfaces are decreased in XRD pattern, which results in the ORR activity improved and overpotential decreased. Heat treatment also has contributed to Ag–Ni/C electrochemistry stability in some degree. - Highlights: • Ag–Ni/C is applied as cathode catalyst for AFCs (alkaline fuel cells). • Ag 3 Ni/C-500 °C shows the best performance. • Non-equilibrium state of Ag–Ni alloy by heat treatment is observed. • The decreased Ag(111) surfaces are favor to improve the catalyst activity

Establishment of quality control technology for HTR fuel in Korea

International Nuclear Information System (INIS)

Lee, Young-Woo; Kim, Woong Ki; Kim, Yeon Ku; Cho, Moon Sung

2009-01-01

Korea is currently developing the HTR coated particle fuel technology in view of its long-term Nuclear Hydrogen Production Technology Development and Demonstration (NHDD) Project, which was launched in 2004, of an extensive R and D program on technology development for a hydrogen production by a VHTR. The current NHDD Project essentially covers the R and D works on the core and reactor system analysis, thermo-hydraulics and safety, coated particle fuel technology, material and component aspects and the hydrogen production technology by using the so-called Sulfur-Iodine Process (S-I Process). As a part of the NHDD Project, the fundamental technology for the coated particle fuel has been being developed, which consist of UO 2 kernel fabrication, pyrolytic carbon (PyC) and silicon carbide (SiC) coating technology, an in-reactor performance model development of a coated particle fuel and a preliminary preparative study for the irradiation tests of the coated particle fuel specimens in the HANARO reactor. In parallel with the development of fabrication process technology of the coated particle fuel, namely, kernel fabrication and coating processes, the characterization techniques for the important characteristics and quality control (QC) methods of the products after each process step were established. This paper deals with the works carried out for the development of the characterization technologies and establishment of the QC techniques for the coated fuel particles. Emphasis is given to the selection and development of the laboratory equipment and apparatus for the development of the methods of the characterizations and relevant QC methods

Device for reprocessing nuclear fuels

International Nuclear Information System (INIS)

Hatano, Mamoru.

1981-01-01

Purpose: To readily discharge a nuclear fuel by burning the nuclear fuel as it is without a pulverizing step and removing the graphite and other coated fuel particles. Constitution: An oxygen supply pipe is connected to the lower portion of a discharge chamber having an inlet for the fuel, and an exhaust pipe is connected to the upper portion of the chamber. The fuel mounted on a metallic gripping member made of metallic material is inserted from the inlet, the gripping member is connected through a conductor to a voltage supply unit, oxygen is then supplied through the oxygen supply tube to the discharge chamber, the voltage supply unit is subsequently operated, and discharge takes place among the fuels. Thus, high heat is generated by the discharge, the graphite carbon of the fuel is burnt, silicon carbide is destroyed and decomposed, the isolated nuclear fuel particles are discharged from the exhaust port, and the combustion gas and small embers are exhausted from the exhaust tube. Accordingly, radioactive dusts are not so much generated as when using a mechanical pulverizing means, and prescribed objective can be achieved. (Yoshino, Y.)

Modeling the burnout of solid polydisperse fuel under the conditions of external heat transfer

Science.gov (United States)

Skorik, I. A.; Goldobin, Yu. M.; Tolmachev, E. M.; Gal'perin, L. G.

2013-11-01

A self-similar burnout mode of solid polydisperse fuel is considered taking into consideration heat transfer between fuel particles, gases, and combustion chamber walls. A polydisperse composition of fuel is taken into account by introducing particle distribution functions by radiuses obtained for the kinetic and diffusion combustion modes. Equations for calculating the temperatures of particles and gases are presented, which are written for particles average with respect to their distribution functions by radiuses taking into account the fuel burnout ratio. The proposed equations take into consideration the influence of fuel composition, air excess factor, and gas recirculation ratio. Calculated graphs depicting the variation of particle and gas temperatures, and the fuel burnout ratio are presented for an anthracite-fired boiler.

The motion of discs and spherical fuel particles in combustion burners based on Monte Carlo simulation

Energy Technology Data Exchange (ETDEWEB)

Granada, E.; Patino, D.; Porteiro, J.; Collazo, J.; Miguez, J.L.; Moran, J. [University of Vigo, E.T.S. Ingenieros Industriales, Lagoas-Marcosende s/n, 36200-Vigo (Spain)

2010-04-15

The position of pellet fuel particles in a burner largely determines their combustion behaviour. This paper addresses the simulated motion of circles and spheres, equivalent to pellet, and their final position in a packed bed subject to a gravitational field confined inside rigid cylindrical walls. A simplified Monte Carlo statistical technique has been described and applied with the standard Metropolis method for the simulation of movement. This simplification provides an easier understanding of the method when applied to solid fuels in granular form, provided that they are only under gravitational forces. Not only have we contrasted one parameter, as other authors, but three, which are radial, bulk and local porosities, via Voronoi tessellation. Our simulations reveal a structural order near the walls, which declines towards the centre of the container, and no pattern was found in local porosity via Voronoi. Results with this simplified method are in agreement with more complex previously published studies. (author)

The motion of discs and spherical fuel particles in combustion burners based on Monte Carlo simulation

International Nuclear Information System (INIS)

Granada, E.; Patino, D.; Porteiro, J.; Collazo, J.; Miguez, J.L.; Moran, J.

2010-01-01

The position of pellet fuel particles in a burner largely determines their combustion behaviour. This paper addresses the simulated motion of circles and spheres, equivalent to pellet, and their final position in a packed bed subject to a gravitational field confined inside rigid cylindrical walls. A simplified Monte Carlo statistical technique has been described and applied with the standard Metropolis method for the simulation of movement. This simplification provides an easier understanding of the method when applied to solid fuels in granular form, provided that they are only under gravitational forces. Not only have we contrasted one parameter, as other authors, but three, which are radial, bulk and local porosities, via Voronoi tessellation. Our simulations reveal a structural order near the walls, which declines towards the centre of the container, and no pattern was found in local porosity via Voronoi. Results with this simplified method are in agreement with more complex previously published studies.

Fuel element for a nuclear reactor

International Nuclear Information System (INIS)

Tanihiro, Yasunori; Sumita, Isao.

1970-01-01

An improved fuel element of the heat pipe type is disclosed in which the fuel element itself is given a heat pipe structure and filled with a coated particle fuel at the section thereof having a capillary tube construction, whereby the particular advantages of heat pipes and coated fuels are combined and utilized to enhance thermal control and reactor efficiency. In an embodiment, the fuel element of the present invention is filled at its lower capillary tube section with coated fuel and at its upper section with a granurated neutron absorber. Both sections are partitioned from the central shaft by a cylindrically shaped wire mesh defining a channel through which the working liquid is vaporized from below and condensed by the coolant external to the fuel element. If the wire mesh is chosen to have a melting point lower than that of the fuel but higher than that of the operating temperature of the heat pipe, the mesh will melt and release the neutron absorbing particles should hot spots develop, thus terminating fission. (Owens, K. J.)

An inspection standard of fuel for the high temperature engineering test reactor

International Nuclear Information System (INIS)

Kobayashi, Fumiaki; Shiozawa, Shusaku; Sawa, Kazuhiro; Sato, Sadao; Hayashi, Kimio; Fukuda, Kosaku; Kaneko, Mitsunobu; Sato, Tsutomu.

1992-06-01

The High Temperature Engineering Test Reactor (HTTR) uses the fuel comprising coated fuel particles. A general inspection standard for the coated particle fuel, however, has not been established in Japan. Therefore, it has been necessary to prescribe the inspection standard of the fuel for HTTR. Under these circumstances, a fuel inspection standard of HTTR has been established under cooperation of fuel specialists both inside and outside of JAERI on referring to the inspection methods adopted in USA, Germany and Japan for HTGR fuels. Since a large number of coated fuel particle samples is needed to inspect the HTTR fuel, the sampling inspection standard has also been established considering the inspection efficiency. This report presents the inspection and the sampling standards together with an explanation of these standards. These standards will be applied to the HTTR fuel acceptance tests. (author)

HTGR fuel reprocessing pilot plant: results of the sequential equipment operation

International Nuclear Information System (INIS)

Strand, J.B.; Fields, D.E.; Kergis, C.A.

1979-05-01

The second sequential operation of the HTGR fuel reprocessing cold-dry head-end pilot plant equipment has been successfully completed. Twenty standard LHGTR fuel elements were crushed to a size suitable for combustion in a fluid bed burner. The graphite was combusted leaving a product of fissile and fertile fuel particles. These particles were separated in a pneumatic classifier. The fissile particles were fractured and reburned in a fluid bed to remove the inner carbon coatings. The remaining products are ready for dissolution and solvent extraction fuel recovery

Fuel decontamination at Ringhals 1 with the new decontamination process IcedecTM

International Nuclear Information System (INIS)

Fredriksson, E.; Ivars, R.; Rosengren, A.; Granath, G.

2003-01-01

The new fuel decontamination technique ICEDEC TM , which has been developed by Westinghouse, is based on abrasion of fuel crud with ice particles. A mixture of ice and water is led continuously through the fuel assembly, which is placed in a specially designed fuel decontamination container connected to a closed loop recirculation system. The ice particles scrape off the loose crud from the fuel surfaces and a mixture of crud and water from the melted ice is then led to a filter unit were the crud is separated from the water. In this paper results of fuel decontamination tests of two-year-old and spent fuel assemblies during spring 2001 at Ringhals 1 are presented. The fuel crud was only released when ice particles passed through the fuel assembly and stopped within ten seconds after the feeding of ice particles had ceased. The activity release from the fuel could thus be performed in a controlled way making the process easy to manage and survey. Activity measurements confirmed that about 50% of the loose crud was removed from the fuel surfaces of the two-year-old assembly. Fuel inspection after the decontamination process showed no influence on the fuel integrity. Furthermore, no enhanced personnel radiation dose was involved with the fuel decontamination compared to normal fuel services. (authors)

Molybdenum-base cermet fuel development

International Nuclear Information System (INIS)

Gurwell, W.E.; Moss, R.W.; Pilger, J.P.; White, G.D.

1987-07-01

Development of a multimegawatt (MMW) space nuclear power system requires identification and resolution of several technical feasibility issues before selecting one or more promising system concepts. Demonstration of reactor fuel fabrication technology is required for cermet-fueled reactor concepts. MMW reactor fuel development activity at Pacific Northwest Laboratory (PNL) is focused on producing a molybdenum-matrix uranium-nitride (UN) fueled cermet. This cermet is to have a high matrix density (≥95%) for high strength and high thermal conductance coupled with a high particle (UN) porosity (∼25%) for retention of released fission gas at high burnup. Fabrication process development involves the use of porous TiN microspheres as surrogate fuel material until porous UN microspheres become available. Process development has been conducted in the areas of microsphere synthesis, particle sealing/coating, and high-energy-rate forming (HERF) and vacuum hot press consolidation techniques. This paper summarizes the status of these activities

Particle control studies on Tore Supra

International Nuclear Information System (INIS)

Mioduszewski, P.

1987-01-01

The report consists of viewgraphs. The goal of the particle control program at Tore Supra is to study plasma performance with strong pellet fueling and corresponding particle exhaust in a limiter tokamak

A hazard to health? Fine particles arouse worldwide interest

Energy Technology Data Exchange (ETDEWEB)

Karas, J; Oesch, P

1998-07-01

The most recent studies show that particles contained in the air that we breathe may have harmful effects on the health of asthmatics, children and old people in particular. Particle material found in ambient air is formed by emissions resulting from traffic, industry and other use of fuels. Nature`s own sources also have a significant effect on particle concentrations. The mechanisms by which fine particles may produce negative health effects are so far unknown. At present it is therefore impossible to assess the effects of emissions of fine particles resulting, for instance, from the use of fossil fuels

Fabrication of fully ceramic microencapsulated fuel by hot pressing

International Nuclear Information System (INIS)

Lee, H. G.; Kim, D. J; Park, J. Y.; Kim, W. J.; Lee, S. J

2014-01-01

Fully ceramic microencapsulated(FCM) nuclear fuel is one of the recently suggested concept to enhance stability nuclear fuel itself. The requirements to increase the accident tolerance of nuclear fuel are mainly two parts: First, the performance has to be maintained compared to the existing UO 2 nuclear fuel and zircaloy cladding system under the normal operation condition. Second, under the severe accident condition, the high temperature structural integrity has to be kept and the generation rate of hydrogen has to be decrease largely. FCM nuclear fuel consists of tristructural isotropic(TRISO) fuel particle and SiC matrix. The relative thermal conductivity of the SiC matrix as compared to UO 2 is quite good, yielding as-irradiated fuel centerline temperature compared to high temperature for the existing fuel leading to reduced stored energy in the core and reduced operational release of fission products from the fuel. Generally SiC ceramics are fabricated via liquid phase sintering due to strong covalent bonding property and low self-diffusivity coefficient. Hot pressing is very effective method to conduct sintering of SiC powder including different second phase. In this study, SiC-matrix composite including TRISO particles were sintered by hot pressing with Al 2 O 3 -Y 2 O 3 additive system. Various sintering condition were investigated to obtain high relative density above 95%. The internal distribution of TRISO particles within SiC-matrix composite was observed by x-ray radiograph. From the analysis of the cross-section of SiC-matrix composite, the fracture of TRISO particles was investigated. In order to uniform distribution of TRISO particle embedded in the SiC matrix, SiC powder overcoating is considered. SiC matrix composite including TRISO was fabricated by hot pressing. FCM pallets with full density were obtained with Al 2 O 3 -Y 2 O 3 additive system. From the microstructure image, the effect of the sintering additive contents and sintering mechanism

Fueling of magnetic-confinement devices

International Nuclear Information System (INIS)

Milora, S.L.

1981-01-01

A general overview of the fueling of magnetic confinement devices is presented, with particular emphasis on recent experimental results. Various practical fueling mechanisms are considered, such as cold gas inlet (or plasma edge fueling), neutral beam injection, and injection of high speed cryogenic hydrogen pellets. The central role played by charged particle transport and recycle of plasma particles from material surfaces in contact with the plasma is discussed briefly. The various aspects of hydrogen pellet injection are treated in detail, including applications to the production of high purity startup plasmas for stellarators and other devices, refueling of tokamak plasmas, pellet ablation theory, and the technology and performance characteristics of low and high speed pellet injectors

Advances in High Temperature Gas Cooled Reactor Fuel Technology

International Nuclear Information System (INIS)

2012-12-01

This publication reports on the results of a coordinated research project on advances in high temperature gas cooled reactor (HTGR) fuel technology and describes the findings of research activities on coated particle developments. These comprise two specific benchmark exercises with the application of HTGR fuel performance and fission product release codes, which helped compare the quality and validity of the computer models against experimental data. The project participants also examined techniques for fuel characterization and advanced quality assessment/quality control. The key exercise included a round-robin experimental study on the measurements of fuel kernel and particle coating properties of recent Korean, South African and US coated particle productions applying the respective qualification measures of each participating Member State. The summary report documents the results and conclusions achieved by the project and underlines the added value to contemporary knowledge on HTGR fuel.

Advances in High Temperature Gas Cooled Reactor Fuel Technology

International Nuclear Information System (INIS)

2012-06-01

This publication reports on the results of a coordinated research project on advances in high temperature gas cooled reactor (HTGR) fuel technology and describes the findings of research activities on coated particle developments. These comprise two specific benchmark exercises with the application of HTGR fuel performance and fission product release codes, which helped compare the quality and validity of the computer models against experimental data. The project participants also examined techniques for fuel characterization and advanced quality assessment/quality control. The key exercise included a round-robin experimental study on the measurements of fuel kernel and particle coating properties of recent Korean, South African and US coated particle productions applying the respective qualification measures of each participating Member State. The summary report documents the results and conclusions achieved by the project and underlines the added value to contemporary knowledge on HTGR fuel.

Irradiation behavior of miniature experimental uranium silicide fuel plates

International Nuclear Information System (INIS)

Hofman, G.L.; Neimark, L.A.; Mattas, R.F.

1983-01-01

Uranium silicides, because of their relatively high uranium density, were selected as candidate dispersion fuels for the higher fuel densities required in the Reduced Enrichment Research and Test Reactor (RERTR) Program. Irradiation experience with this type of fuel, however, was limited to relatively modest fission densities in the bulk from, on the order of 7 x 10 20 cm -3 , far short of the approximately 20 x 10 20 cm -3 goal established for the RERTR program. The purpose of the irradiation experiments on silicide fuels on the ORR, therefore, was to investigate the intrinsic irradiation behavior of uranium silicide as a dispersion fuel. Of particular interest was the interaction between the silicide particles and the aluminum matrix, the swelling behavior of the silicide particles, and the maximum volume fraction of silicide particles that could be contained in the aluminum matrix

Investigations of the transportation characteristics of biomass fuel particles in a horizontal pipeline through CFD modelling and experimental measurement

International Nuclear Information System (INIS)

Gubba, S.R.; Ingham, D.B.; Larsen, K.J.; Ma, L.; Pourkashanian, M.; Qian, X.; Williams, A.; Yan, Y.

2012-01-01

Recent national and international emission legislations to reduce emissions of carbon dioxide are forcing power generation industries using coal to look at various alternatives, such as biomass and especially by co-firing techniques. Biomass is transported to the burners either mixed with the primary fuel, in general, coal, or used in dedicated pipelines. In both cases, transportation of biomass is difficult due to its composition, size, shape and physical behaviour in comparison to the transportation of coal. This study considers experimental measurements for biomass particle transportation in a pipeline with a transverse elbow and compares the results with those using computation fluid dynamic (CFD) techniques. Various materials: flour, willow, wood, bark and a mixture of flour and willow, have been considered in the present investigation. The experimental work was performed using the dynamic changes in the electrostatic charges of biomass particles in conjunction with correlation signal processing techniques. The CFD simulations were performed by considering the effects of gravity, non-spherical drag (based on estimated shape factor), detailed information of the particle distribution, particle wall collisions and particle–particle interactions. Good quantitative and qualitative agreement was obtained between the CFD simulations and the experimental data. It is concluded that particle–particle interactions are of less importance if the mass loading ratio of particles to air is less than 0.03. -- Highlights: ► Dispersed biomass particle transportation is studied using experiments and CFD. ► Inclusion of asphericity in the drag model clearly demonstrated the improvements. ► Gravity effects are found to be important for correct particle distribution in pipe lines. ► Inter-particle collisions were less important for mass loading ratios <0.05 kg/kg.

An Experiment on the Carbonization of Fuel Compact Matrix Graphite for HTGR

International Nuclear Information System (INIS)

Lee, Young Woo; Kim, Joo Hyoung; Cho, Moon Sung

2012-01-01

The fuel element for HTGR is manufactured by mixing coated fuel particles with matrix graphite powder and forming into either pebble type or cylindrical type compacts depending on their use in different HTGR cores. The coated fuel particle, the so-called TRISO particle, consists of 500-μm spherical UO 2 particles coated with the low density buffer Pyrolytic Carbon (PyC) layer, the inner and outer high density PyC layer and SiC layer sandwiched between the two inner and outer PyC layers. The coated TRISO particles are mixed with a properly prepared matrix graphite powder, pressed into a spherical shape or a cylindrical compact, and finally heat-treated at about 1800 .deg. C. These fuel elements can have different sizes and forms of compact. The basic steps for manufacturing a fuel element include preparation of graphite matrix powder, over coating the fuel particles, mixing the fuel particles with a matrix powder, carbonizing green compact, and the final high-temperature heat treatment of the carbonized fuel compact. The carbonization is a process step where the binder that is incorporated during the matrix graphite powder preparation step is evaporated and the residue of the binder is carbonized during the heat treatment at about 1073 K, In order to develop a fuel compact fabrication technology, and for fuel matrix graphite to meet the required material properties, it is of extreme importance to investigate the relationship among the process parameters of the matrix graphite powder preparation, fabrication parameters of fuel element green compact and the carbonization condition, which has a strong influence on further steps and the material properties of fuel element. In this work, the carbonization behavior of green compact samples prepared from the matrix graphite powder mixtures with different binder materials was investigated in order to elucidate the behavior of binders during the carbonization heat treatment by analyzing the change in weight, density and its

Physical characterization of the fine particle emissions from commercial aircraft engines during the Aircraft Particle Emissions eXperiment (APEX) 1-3

Science.gov (United States)

Kinsey, John S.; Dong, Yuanji; Williams, D. Craig; Logan, Russell

2010-06-01

The fine particulate matter (PM) emissions from nine commercial aircraft engine models were determined by plume sampling during the three field campaigns of the Aircraft Particle Emissions Experiment (APEX). Ground-based measurements were made primarily at 30 m behind the engine for PM mass and number concentration, particle size distribution, and total volatile matter using both time-integrated and continuous sampling techniques. The experimental results showed a PM mass emission index (EI) ranging from 10 to 550 mg kg -1 fuel depending on engine type and test parameters as well as a characteristic U-shaped curve of the mass EI with increasing fuel flow for the turbofan engines tested. Also, the Teflon filter sampling indicated that ˜40-80% of the total PM mass on a test-average basis was comprised of volatile matter (sulfur and organics) for most engines sampled. The number EIs, on the other hand, varied from ˜10 15 to 10 17 particles kg -1 fuel with the turbofan engines exhibiting a logarithmic decay with increasing fuel flow. Finally, the particle size distributions of the emissions exhibited a single primary mode that were lognormally distributed with a minor accumulation mode also observed at higher powers for all engines tested. The geometric (number) mean particle diameter ranged from 9.4 to 37 nm and the geometric standard deviation ranged from 1.3 to 2.3 depending on engine type, fuel flow, and test conditions.

Particles of spilled oil-absorbing carbon in contact with water

Science.gov (United States)

Muradov, Nazim [Melbourne, FL

2011-03-29

Hydrogen generator coupled to or integrated with a fuel cell for portable power applications. Hydrogen is produced via thermocatalytic decomposition (cracking, pyrolysis) of hydrocarbon fuels in oxidant-free environment. The apparatus can utilize a variety of hydrocarbon fuels, including natural gas, propane, gasoline, kerosene, diesel fuel, crude oil (including sulfurous fuels). The hydrogen-rich gas produced is free of carbon oxides or other reactive impurities, so it could be directly fed to any type of a fuel cell. The catalysts for hydrogen production in the apparatus are carbon-based or metal-based materials and doped, if necessary, with a sulfur-capturing agent. Additionally disclosed are two novel processes for the production of two types of carbon filaments, and a novel filamentous carbon product. Carbon particles with surface filaments having a hydrophobic property of oil film absorption, compositions of matter containing those particles, and a system for using the carbon particles for cleaning oil spills.

Characterization of drying parameters for solid fuels; Kiinteiden polttoaineiden kuivumisparametrien karakterisointi

Energy Technology Data Exchange (ETDEWEB)

Impola, R. [VTT Energy, Jyvaeskylae (Finland). Fuels Production; Saastamoinen, J. [VTT Energy, Jyvaeskylae (Finland). Energy Production Technologies; Fagernaes, L. [VTT Energy, Espoo (Finland). Energy Production Technologies

1995-12-31

VTT Energy has investigated the drying technology of fuels for some years. The main focus has been on research of the fundamentals and modelling of the drying. Experimental research has been carried out using equipment of various sizes. The research has created profound information on the behaviour of fuels and on the reduction of emissions. Drying technology is a part of the quality control of biofuels and other moist in-homogeneous fuels before the combustion process. The drying of fuels influences operational behaviour and efficiency of the combustion equipment, dimensioning of the equipment and the reduction of emissions. New drying technologies make it possible to use new moist fuels and develop their production technologies. In this project VTT Energy has studied the factors influencing the drying, including drying of a single fuel particle in low temperatures (50-200 deg C) and the drying of a single fuel particle in steam under various pressures. Also, the drying of biomass fuel particles in fixed and moving beds with hot gas or steam is considered both experimentally and theoretically. A single particle drying model is coupled with a model describing heat and moisture transfer in the gas phase of the bed. The size of the bed to reach a certain degree of drying depends mostly on the following parameters: particle size, particle moisture content, gas inlet temperature, gas inlet moisture content and gas mass flow rate. As a special case, experiments simulating wood chip drying in a fixed bed and in counterflow were carried out. This research will also yield profound information on emissions of various dryer technologies and various fuels, as well as on factors influencing the emissions

Characterization of drying parameters for solid fuels; Kiinteiden polttoaineiden kuivumisparametrien karakterisointi

Energy Technology Data Exchange (ETDEWEB)

Impola, R [VTT Energy, Jyvaeskylae (Finland). Fuels Production; Saastamoinen, J [VTT Energy, Jyvaeskylae (Finland). Energy Production Technologies; Fagernaes, L [VTT Energy, Espoo (Finland). Energy Production Technologies

1996-12-31

VTT Energy has investigated the drying technology of fuels for some years. The main focus has been on research of the fundamentals and modelling of the drying. Experimental research has been carried out using equipment of various sizes. The research has created profound information on the behaviour of fuels and on the reduction of emissions. Drying technology is a part of the quality control of biofuels and other moist in-homogeneous fuels before the combustion process. The drying of fuels influences operational behaviour and efficiency of the combustion equipment, dimensioning of the equipment and the reduction of emissions. New drying technologies make it possible to use new moist fuels and develop their production technologies. In this project VTT Energy has studied the factors influencing the drying, including drying of a single fuel particle in low temperatures (50-200 deg C) and the drying of a single fuel particle in steam under various pressures. Also, the drying of biomass fuel particles in fixed and moving beds with hot gas or steam is considered both experimentally and theoretically. A single particle drying model is coupled with a model describing heat and moisture transfer in the gas phase of the bed. The size of the bed to reach a certain degree of drying depends mostly on the following parameters: particle size, particle moisture content, gas inlet temperature, gas inlet moisture content and gas mass flow rate. As a special case, experiments simulating wood chip drying in a fixed bed and in counterflow were carried out. This research will also yield profound information on emissions of various dryer technologies and various fuels, as well as on factors influencing the emissions

Deep-Burn Modular Helium Reactor Fuel Development Plan

Energy Technology Data Exchange (ETDEWEB)

McEachern, D

2002-12-02

This document contains the workscope, schedule and cost for the technology development tasks needed to satisfy the fuel and fission product transport Design Data Needs (DDNs) for the Gas Turbine-Modular Helium Reactor (GT-MHR), operating in its role of transmuting transuranic (TRU) nuclides in spent fuel discharged from commercial light-water reactors (LWRs). In its application for transmutation, the GT-MHR is referred to as the Deep-Burn MHR (DB-MHR). This Fuel Development Plan (FDP) describes part of the overall program being undertaken by the U.S. Department of Energy (DOE), utilities, and industry to evaluate the use of the GT-MHR to transmute transuranic nuclides from spent nuclear fuel. The Fuel Development Plan (FDP) includes the work on fuel necessary to support the design and licensing of the DB-MHR. The FDP is organized into ten sections. Section 1 provides a summary of the most important features of the plan, including cost and schedule information. Section 2 describes the DB-MHR concept, the features of its fuel and the plan to develop coated particle fuel for transmutation. Section 3 describes the knowledge base for fabrication of coated particles, the experience with irradiation performance of coated particle fuels, the database for fission product transport in HTGR cores, and describes test data and calculations for the performance of coated particle fuel while in a repository. Section 4 presents the fuel performance requirements in terms of as-manufactured quality and performance of the fuel coatings under irradiation and accident conditions. These requirements are provisional because the design of the DB-MHR is in an early stage. However, the requirements are presented in this preliminary form to guide the initial work on the fuel development. Section 4 also presents limits on the irradiation conditions to which the coated particle fuel can be subjected for the core design. These limits are based on past irradiation experience. Section 5 describes

A review of microstructural analysis on U3Si2-Al plate-type fuel

International Nuclear Information System (INIS)

Ti Zhongxin; Guo Yibai

1995-12-01

The microstructure of U 3 Si 2 -Al plate-type fuel, that is the microstructure of fuel particles, compatibility of the fuel particles and Al matrix, fuel particles distribution, dogbone area morphology, clad and meat thickness, bone quality of clad/frame and clad/fuel core, and the effect of these factors on products quality were comprehensively investigated and analyzed by means of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDX), image processing technique, etc.. The main results are as following: U-7.7%Si alloy contains two phases: primary U 3 Si 2 and small amount of USi (about 12%), free-uranium was not detected in fuel particles; the dogbone area is the key factor affecting fuel plate quality (1 ref., 16 figs., 4 tabs.)

Characteristics of spray from a GDI fuel injector for naphtha and surrogate fuels

KAUST Repository

Wang, Libing

2016-11-18

Characterization of the spray angle, penetration, and droplet size distribution is important to analyze the spray and atomization quality. In this paper, the spray structure development and atomization characterization of two naphtha fuels, namely light naphtha (LN) and whole naphtha (WN) and two reference fuel surrogates, i.e. toluene primary reference fuel (TPRF) and primary reference fuel (PRF) were investigated using a gasoline direct injection (GDI) fuel injector. The experimental setup included a fuel injection system, a high-speed imaging system, and a droplet size measurement system. Spray images were taken by using a high-speed camera for spray angle and penetration analysis. Sauter mean diameter, Dv(10), Dv(50), Dv(90), and particle size distribution were measured using a laser diffraction technique. Results show that the injection process is very consistent for different runs and the time averaged spray angles during the measuring period are 103.45°, 102.84°, 102.46° and 107.61° for LN, WN, TPRF and PRF, respectively. The spray front remains relatively flat during the early stage of the fuel injection process. The peak penetration velocities are 80 m/s, 75 m/s, 75 m/s and 79 m/s for LN, WN, TPRF and PRF, respectively. Then velocities decrease until the end of the injection and stay relatively stable. The transient particle size and the time-averaged particle size were also analyzed and discussed. The concentration weighted average value generally shows higher values than the arithmetic average results. The average data for WN is usually the second smallest except for Dv90, of which WN is the biggest. Generally the arithmetic average particle sizes of PRF are usually the smallest, and the sizes does not change much with the measuring locations. For droplet size distribution results, LN and WN show bimodal distributions for all the locations while TPRF and PRF shows both bimodal and single peak distribution patterns. The results imply that droplet size

Particle Emissions from Biomass Combustion

Energy Technology Data Exchange (ETDEWEB)

Szpila, Aneta; Bohgard, Mats [Lund Inst. of Technology (Sweden). Div. of Ergonomics and Aerosol Technology; Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Div. of Bioenergy Technology; Pagels, Joakim; Rissler, Jenny; Swietlicki, Erik; Gharibi, Arash [Lund Univ. (Sweden). Div. of Nuclear Physics

2003-05-01

We have shown that high concentrations of fine particles of the order of 2-7x10{sup -7} particles per cm{sup 3} are being formed in all the combustion units studied. There was a higher difference between the units in terms of particle mass concentrations. While the largest differences was found for gas-phase constituents (CO and THC) and polyaromatic hydrocarbons. In 5 out of 7 studied units, multi-cyclones were the only measure for flue-gas separation. The multicyclones had negligible effect on the particle number concentration and a small effect on the mass of particles smaller than 5 {mu}m. The separation efficiency was much higher for the electrostatic precipitators. The boiler load had a dramatic influence on the coarse mode concentration during combustion of forest residue. PM0.8-6 increased from below 5 mg/m{sup 3} to above 50 mg/m{sup 3} even at a moderate change in boiler load from medium to high. A similar but less pronounced trend was found during combustion of dry wood. PM0.8-PM6 increased from 12 to 23 mg/m{sup 3} when the load was changed from low to high. When increasing the load, the primary airflow taken through the grate is increased; this itself may lead to a higher potential of the air stream to carry coarse particles away from the combustion zone. Measurements with APS-instrument with higher time-resolution showed a corresponding increase in coarse mode number concentration with load. Additional factor influencing observed higher concentration of coarse mode during combustion of forest residues, could be relatively high ash content in this type of fuel (2.2 %) in comparison to dry wood (0.3 %) and pellets (0.5 %). With increasing load we also found a decrease in PM1 during combustion of forest residue. Whether this is caused by scavenging of volatilized material by the high coarse mode concentration or a result of a different amount of volatilized material available for formation of fine particles needs to be shown in future studies. The

FUJI - a comparative irradiation test with pellet, sphere-pac, and vipac fuel

International Nuclear Information System (INIS)

Hellwig, C.; Bakker, K.; Ozawa, T.; Nakamura, M.; Kihara, Y.

2004-01-01

Particle fuels such as sphere-pac and vipac fuels have been considered as promising fuel systems for fast reactors, due to their inherent potential in remote operation, cost reduction and incineration of minor actinides or low-decontaminated plutonium. The FUJI test addresses the questions of fabrication of MOX particle fuels with high Pu content (20%) and its irradiation behaviour during the start-up phase. Four kinds of fuel, i.e. MOX sphere-pac, MOX vipac, MOX pellet and Np-MOX sphere-pac fuel, have been and will be simultaneously irradiated under identical conditions in the High Flux Reactor in Petten. First results show that the particle fuel undergoes a dramatic structure change already at the very beginning of the irradiation when the maximum power is reached. The structural changes, i.e. the formation of a central void and the densification of fuel, decrease the fuel central temperature. Thus the fast and strong restructuring helps to prevent central fuel melting at high power levels. (authors)

Irradiation behavior of uranium oxide - Aluminum dispersion fuel

International Nuclear Information System (INIS)

Hofman, Gerard L.; Rest, Jeffrey; Snelgrove, James L.

1996-01-01

An oxide version of the DART code has been generated in order to assess the irradiation behavior of UO 2 -Al dispersion fuel. The aluminum-fuel interaction models were developed based on U 3 O 8 -Al irradiation data. Deformation of the fuel element occurs due to fuel particle swelling driven by both solid and gaseous fission products and as a consequence of the interaction between the fuel particles and the aluminum matrix. The calculations show that, with the assumption that the correlations derived from U 3 O 8 are valid for UO 2 , the LEU UO 2 -Al with a 42% fuel volume loading (4 g U/cm 3 ) irradiated at fuel temperatures greater than 413 K should undergo breakaway swelling at core burnups greater than about 1.12 x 10 27 fissions m -3 (∼63% 235 U burnup). (author)

Irradiation behavior of uranium oxide-aluminum dispersion fuel

International Nuclear Information System (INIS)

Hofman, G.L.; Rest, J.; Snelgrove, J.L.

1996-01-01

An oxide version of the DART code has been generated in order to assess the irradiation behavior of UO 2 -Al dispersion fuel. The aluminum-fuel interaction models were developed based on U 3 O 8 -Al irradiation data. Deformation of the fuel element occurs due to fuel particle swelling driven by both solid and gaseous fission products, as well as a consequence of the interaction between the fuel particles and the aluminum matrix. The calculations show, that with the assumption that the correlations derived from U 3 O 8 are valid for UO 2 , the LEU UO 2 -Al with a 42% fuel volume loading (4 gm/cc) irradiated at fuel temperatures greater than 413 K should undergo breakaway swelling at core burnups greater than about 1.12 x 10 27 fissions m -3 (∼ 63% 235 U burnup)

Study on the nitride fuel fabrication for FBR cycle (1)

International Nuclear Information System (INIS)

Shinkai, Yasuo; Ono, Kiyoshi; Tanaka, Kenya

2002-07-01

In the phase-II of JNC's 'Feasibility Study on Commercialized Fuel Reactor Cycle System (the F/S)', the nitride fuels are selected as candidate for fuels for heavy metal cooled reactor, gas cooled reactor, and small scale reactor. In particular, the coated fuel particles are a promising concept for gas cooled reactor. In addition, it is necessary to study in detail the application possibility of pellet nitride fuel and vibration compaction nitride fuel for heavy metal cooled reactor and small scale reactor in the phase-II. In 2001, we studied more about additional equipments for the nitride fuel fabrication in processes from gelation to carbothermic reduction in the vibration compaction method. The result of reevaluation of off-gas mass flow around carbothermic reduction equipment in the palletizing method, showed that quantity of off-gas flow reduced and its reduction led the operation cost to decrease. We studied the possibility of fabrication of large size particles in the coated fuel particles for helium gas cooled reactor and we made basic technical issues clear. (author)

Detailed SEM-EPMA investigation of high specific radioactivity particles (hot particles)

International Nuclear Information System (INIS)