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Sample records for des elements combustibles

  1. Automatic welding of fuel elements; Soudure automatique des elements combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Briola, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    The welding process depends on the type of fuel element, the can material and the number of cartridges to be welded: - inert-gas welding (used for G2 and the 1. set of EL3), - inert atmosphere arc welding (used for welding uranium and zirconium), - electronic welding (used for the 2. set of EL3 and the tank of Proserpine). (author) [French] Suivant le type d'element combustible, le materiau de gaine et l'importance de la serie a fabriquer, le soudeur dispose des differents procedes examines dans cette communication: - soudure classique a l'arc sous gaz inerte (utilisee pour G2 et le premier jeu EL3), - soudure en atmosphere complete d'argon (utilisee pour la soudure d'uranium et de zirconium), - soudure electronique (utilisee pourdeuxieme jeu EL3 et la cuve de Proserpine). (auteur)

  2. The industrial production of fuel elements; La fabrication en france des elements combustibles

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    Boussard, R [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires; Nadal, J [Societe Industrielle de Combustible Nucleaire (SICN), 75 - Paris (France); Pellen, A [Compagnie pour l' Etude et la Realisation de Combustibles Atomiques (CERCA), 75 - Paris (France)

    1964-07-01

    -pool type reactors. The authors show how the problem of the industrial production of rolled fuel elements has been solved in France, and give the three steps involved: 1 - Assembly of the plates made in the U.S.A., 2 - Rolling of the cores made in the U.S.A. to obtain the plates, 3 - Fabrication of the U-Al alloy and production of the cores. They then recall briefly the characteristics of the different fuel elements now in production. A description is given of the various stages of the production including information about the equipment; stress is laid on the extent of the controls carried out at each stage. In conclusion the authors consider the future development of this type of production taking into account the improvements planned and those which are possible. (authors) [French] Les auteurs traitent successivement de la fabrication industrielle des elements combustibles pour reacteurs de puissance de la filiere U naturel graphite-gaz et plus particulierement pour les centrales energetiques d'E.D.F. et de celle des elements combustibles a base d'U enrichi destines aux reacteurs experimentaux du type 'piscine'. 1ere Partie - LES ELEMENTS COMBUSTIBLES AVANCES POUR LES REACTEURS E.D.F.: Apres un bref rappel des caracteristiques des elements combustibles actuellement fabriques industriellement pour les reacteurs de MARCOULE et de CHINON, les auteurs indiquent les differentes etapes suivies pour aboutir au stade de la fabrication industrielle d'un element combustible nouveau, tant en ce qui concerne la gaine et eventuellement la chemise de graphite que le combustible lui-meme. Pour ce qui est de l'elaboration du combustible, ils decrivent les differentes operations en insistant sur les points originaux de la fabrication et de l'appareillage tels que: - coulees en moules chauds, - traitement thermique des alliages U.Mo 1 p. 100, - soudure des pastilles de fermeture des tubes, - gainage - controle aux differents stades. En ce qui concerne la fabrication des gaines, ils

  3. Apparatus for examination of irradiated fuel elements of industrial reactors at Marcoule; Appareillage d'examen des elements combustibles des piles industrielles de Marcoule

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    Pesenti, P; Wallet, Ph [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The authors describe a viewing and measurement cell for the slugs of Marcoule industrial reactors. This cell allows visual inspection, and photography of slugs. Length measurements are also made possible by horizontal motion of the slug both in translation and rotation. (author) [French] Les auteurs decrivent une cellule d'observation et de mesure des elements combustibles des piles industrielles de Marcoule. La cellule permet l'examen a vue, la photographie, la radioscopie et la radiographie des elements combustibles. Elle permet en outre la mesure de longueurs sur ces elements, ces derniers pouvant etre deplaces horizontalement en translation, et en rotation. (auteur)

  4. Burnup determination of power reactor fuel elements by gamma spectrometry; Determination par spectrometrie {gamma} du taux d'irradiation des elements combustibles des reacteurs de puissance

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    Robin, M; Jastrzeb, M; Boisliveau, S; Boyer, R; Vidal, R [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    This report describes a method for determining by {gamma} spectrometry the burn up and the specific power of fuel elements irradiated in power reactors. The energy spectrum of {gamma} rays emitted by fission products is measured by means of a simple equipment using a sodium iodide detector and a multichannel analyzer. In order to extract from the spectrum a quantity proportional to the burn up, it is necessary to: - isolate an activity specific of one emitter,- give the same importance to fissions in uranium and plutonium - take into account the radioactive decay during and after irradiation. One hundred fuel elements were studied and burn up values obtained by {gamma} spectrometry are compared to results given by chemical analyses. Preliminary measurements show that the accuracy of the results is greatly increased by the use of a germanium detector, due to its good resolution. (authors) [French] Ce rapport expose une methode de determination par spectrometrie {gamma} du taux d'irradiation et de la puissance specifique des elements combustibles irradies dans les reacteurs de puissance. Une installation simple utilisant un detecteur d'iodure de sodium et un selecteur multicanaux mesure le spectre en energie du rayonnement {gamma} emis par les produits de fission. Afin d'extraire du spectre une quantite proportionnelle au taux de combustion, il faut: - isoler une activite specifique a un emetteur, - donner la meme importance aux fissions survenues dans l'uranium et le plutonium, - prendre en compte la decroissance radioactive pendant et apres l'irradiation. Les mesures ont porte sur une centaine d'elements combustibles et les taux de combustion obtenus par spectrometrie {gamma} sont compares aux resultats des analyses chimiques. Des mesures preliminaires montrent que l'utilisation d'un detecteur de germanium augmente considerablement la precision des resultats, en raison de son excellente resolution. (auteurs)

  5. Fuel elements for pressurised-gas reactors; Elements combustibles des piles a gaz sous pression

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    Stohr, J A; Englander, M; Gauthron, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    The design and fabrication of fuel elements for the first CO{sub 2} pressurized reactors have induced to investigate: various cladding materials, natural uranium base fuels, canning processes. The main analogical tests used in connection with the fuel element study are described. These various tests have enabled, among others, the fabrication of the fuel element for the EL2 reactor. Lastly, future solutions for electrical power producing reactors are foreseen. (author)Fren. [French] L'etude et la realisation d'elements combustibles pour les premieres piles a CO{sub 2} sous pression ont conduit a examiner: les divers materiaux de gaine, les combustibles a base d'uranium naturel, les modes de gainage. Les principaux essais analogiques ayant servi au cours de l'etude de la cartouche sont decrits. Ces divers essais ont notamment permis la realisation de la cartouche de la pile EL2. Enfin sont envisagees les solutions futures pour les piles productrices d'energie electrique. (auteur)

  6. Assessment of End-Plug Welding of Fuel Elements; Evaluation des Soudures Terminales des Elements Combustibles; Otsenka kachestva privarki kontsevoj probki toplivnykh ehlementov; Inspeccion de la Soldadura del Tapon Terminal de los Elementos Combustibles

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    Nakamura, Y.; Aoki, T. [Tokai Refinery, Atomic Fuel Corporation (Japan)

    1965-10-15

    faites pour des elements combustibles du reacteur JRR-3. Il s'agit d'un reacteur de recherche de 10 MW, ralenti et refroidi 3 l'eau lourde, avec des elements combustibles en uranium metallique sous gaine d'aluminium. Comme ces elements n'ont qu'une liaison mecanique entre la gaine et l'ame, il peut exister une contrainte de traction aux bouchons de la gaine sous l'effet du gonflement de l'uranium par suite de l'irradiation. Le traitement thermique provoquera une contrainte analogue dans les soudures. Une corrosion preferentielle provoquee par l'eau chaude peut se produire dans le voisinage des soudures, a cause de la difference de microstructure. Il est essentiel d'assurer l'etancheite pendant et apres l'utilisation dans le reacteur. Des specimens specialement concus ont ete utilises pour les essais d'elasticite, les essais de fluage a haute temperature, les essais thermiques et le controle de la corrosion. Plusieurs sortes de soudures ont fait l'objet d'essais non destructifs avant les controles proprement dits et ont ete verifiees quant a l'etancheite a diverses periodes entre les controles. L'etude critique des resultats obtenus peut permettre de fixer des normes d'inspection, telles que la radiographie par rayons X et l'inspection visuelle des soudures des bouchons. Le memoire donne egalement d'autres resultats pour les elements combustibles avec gaine en Magnox ou en Zircaloy. (author) [Spanish] Es muy importante establecer una correlacion entre los resultados de los ensayos y el rendimiento en los reactores en servicio, asf como perfeccionar los correspondientes metodos de ensayo no destructivo. Ahora bien, resulta algo diffcil lograr la correlacion indicada a causa de los elevados gastos que ello supone y de la intensa radiactividad. Se han efectuado varios estudios fuera del reactor simulando las condiciones que reinan en el interior de este. En el presente documento se exponen algunos datos sobre los ensayos con elementos combustibles del reactor japones de

  7. The health physics of installations for decladding irradiated fuels or for handling radio-elements at Marcoule; La radioprotection des installations de degainage des combustibles irradies et des radio-elements a Marcoule

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    Chassany, J; Guillermin, P; Mallet, P [Commissariat a l' Energie Atomique, Centre de Production de Plutonium de Marcoule, 30 - Chusclan (France)

    1966-07-01

    Radiation protection practices for handling reactor fuel elements are described. Elements of considerable specific radioactivity are handled under water. A study was made of water filtration and of ventilation in the building. The installations are divided up into zones depending on the radioactive risks, and the radiation level atmospheric contamination are the object of a systematic control at various points. A description is given of all aspects of health physics which have been encountered during six years: storage, transfer of radioactive material; decladding, rolling, waste disposal, specialized operations, installations in operation and at rest, and transport. In spite of the gradual increase in the activity of these installations, the total doses received by the personnel have hardly altered and the number of cases of physical contamination has diminished. (authors) [French] Dans ces installations, se manipulent sous l'eau des elements a radioactivite specifique considerable. La filtration de l'eau, la ventilation ont ete particulierement etudiees. L'ensemble a ete divise en lieux classes en fonction des risques radioactifs et des appareils controlent en permanence l'irradiation et la contamination atmospherique en certains points. Tous les aspects de la radioprotection resultant de six annees d'experience relatifs: au stockage, au deconteneurage, au degainage, au laminage, a l'evacuation des residus, aux travaux particuliers, installations en marche et a l'arret, et aux transports sont successivement decrits. Malgre l'accroissement progressif de l'activite de cet ensemble, les doses integrees par le personnel n'ont pratiquement pas augmente et le nombre des cas de contamination corporelle a diminue. (auteurs)

  8. Recent developments concerning French fuel elements used in natural uranium - graphite - CO{sub 2} reactor systems; Developpements recents des elements combustibles francais de la filiere uranium naturel - graphite - CO{sub 2}

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    Salesse, M; Stohr, J A; Jeanpierre, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    internal can of the annular element, has necessitated very much research work. - the exact temperature drop at the contact between the uranium and the can, and the strength of the lower end of the cartridge are points which are increasingly crucial in the case of the annular element. All in all the annular element thus calls for a great research effort. This effort is justified by the big step forwards in which it will result in the case of the EDF reactors thanks to its high specific power and to the high weight of uranium in each cartridge. (authors) [French] La politique choisie en France pour le developpement des elements combustibles destines aux reacteurs de l'Electricite de France, consiste a chercher, pour chaque pile nouvelle, a beneficier au maximum des progres techniques les plus recents en etudiant chaque fois un nouvel element combustible permettant une puissance par canal aussi elevee que possible. Les derniers elements combustibles ainsi etudies par le Commissariat a l'Energie Atomique sont de deux types differents: un element a tube d'uranium ferme aux deux extremites et refroidi exterieurement (ce type d'element, retenu pour les reacteurs EDF 2, EDF 3 et EDF 4 permet des puissances specifiques maximum de l'ordre de 6 MW/t). Un element a tube d'uranium ouvert, refroidi interieurement et exterieurement, appele clemont annulaire et dont on etudie la possibilite pour EDF5. Un tel element peut permettre des puissances specifiques superieures a 12 MW/t. Ces deux types d'elements possedent des caracteristiques communes: la gaine, pour le refroidissement externe, comporte des ailettes en chevron. Ce type de profil, qui a recu recemment des ameliorations notables augmentant son efficacite thermique, a l'avantage important d'eviter les vibrations de cartouche mais a pose des problemes technologiques de tenue au cyclage thermique qui ont necessite une etude approfondie. les cartouches sont placees a l'interieur de chemise en graphite, ce qui limite les efforts

  9. Combustion of Solid Propellants (La Combustion des Propergols Solides)

    Science.gov (United States)

    1991-07-01

    the of ether and ethyl alcohol and removing objective of these lectures to give a this solvent. Instead of having a fibrous comprehensive understanding...do cetto esrne do Les propergols composites, A matrice confifrences une description tout A fait A polymarique charg~o pst, un oxydant at un jour des...rusa., De nouveaux souvant suppos6 qua la vitesa des gaz de oxydes de for ultrafirts mont aujourd’hui combustion est n~gligeable at qua d~velopps pour

  10. Ultrasonic Water-Gap Measurements in MTR Fuel Elements; Mesure par Ultrasons des Espaces Intercalaires dans les Elements Combustibles des Reacteurs d'Essai de Materiaux; Izmereniya vodyanogo zazora v teplovydelyayushchikh ehlementakh dlya materialovedcheskogo reaktora s pomoshch'yu ul'trazvuka; Medicion Ultrasonica de la Capa de Agua en Elementos Combustibles para Reactores de Ensayo de Materiales

    Energy Technology Data Exchange (ETDEWEB)

    Deknock, R. [Metallurgy Department, S.C.K./C.E.N., Mol (Belgium)

    1965-10-15

    generalement eleves, il est indispensable de prevoir un transfert de chaleur uniforme et un refroidissement regulier empechant toute formation massive de vapeur. En outre, pour determiner le gonflement et le comportement general du combustible dans le reacteur, il faudra mesurer les espaces intercalaires dans les elements combustibles au cours de controles apres irradiation. A cette fin, on a mis au point une sonde fondee sur le principe des ultrasons, qui permet de mesurer les espaces intercalaires de 3 mm sur 1 m de long dans les elements combustibles du reacteur BR-2. Lorsqu'on procede a des experiences apres irradiation, la sonde doit pouvoir fonctionner dans un element combustible immerge dans un reservoir d'eau a une profondeur de 6 m au minimum. La sonde peut resister a une immersion prolongee dans l'eau et n'est pas endommagee par une irradiation gamma a des doses normales. Bien que le systeme soit fonde sur la methode classique de la reflexion des impulsions, il permet de separer les impulsions emises des impulsions reflechies au moyen d'un cristal ferroelectrique de 10 MHz a pouvoir eleve de dispersion de l'energie. Les resultats des mesures peuvent etre lus directement sur un oscilloscope: le temps est indique sur l'axe horizontal et la vitesse d'exploration est reglee de maniere a se trouver en relation directe avec la vitesse de propagation de l'onde, c'est-a-dire avec la distance intercalaire. Ce mode de lecture est satisfaisant lorsqu'on procede a un nombre limite de mesures, mais il est evidemment preferable d'enregistrer les resultats sur un graphique. Dans ce cas, les impulsions incidentes et les impulsions reflechies sont transmises a un convertisseur temps-tension au moyen d'un circuit logique transistorise. Cet appareil permet un ajustement continu du zero de sortie pour toute distance intercalaire choisie arbitrairement entre 2 et 4 mm, grace a quoi on peut obtenir un enregistrement autour d'un axe zero. En outre, toute variation de 100 {mu}m de la

  11. Burn up physics; Physique des combustibles irradies

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    Tretiakoff, O [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    requires samples of the order of several kilograms only. The relationships between these measurements and the investigations of lattices are discussed, and an outline is given of the way of carrying out the systematic study of fuels of various compositions. The method has been successfully applied to the systematic study of irradiated fuels (analysed independently by the methods mentioned above) thus giving the possibility of measuring in situ the absorption of fission products. (author) [French] Cette communication expose un ensemble d'etudes theoriques et d'experiences, effectuees au CEA et destinees a faire progresser la connaissance de l'evolution de la reactivite (au cours de l'irradiation du combustible) dans les reacteurs a uranium naturel ou faiblement enrichi.,. On rappelle les difficultes de l'experimentation directe sur des masses importantes de combustible irradie - en particulier dans les reacteurs de puissance en fonctionnement - et on souligne la necessite d'experiences a caractere fondamental distinguant: d'une part l'evolution de la composition des combustibles (chaines de noyaux lourds, produits de fission), d'autre part l'effet des modifications de composition sur le bilan de neutrons. Avant de presenter trois categories d'experiences que l'on est conduit a entreprendre, on rappelle l'importance des problemes lies aux spectres de neutrons et on decrit rapidement les methodes pratiques de calcul utilisees. L'irradiation systematique de quelques types de combustibles, suivie de leur analyse chimique et isotopique est en cours depuis plusieurs annees. On donne un apercu de l'ensemble du programme experimental et on decrit les moyens et les methodes mis en oeuvre: chaine {alpha}, {beta}, {gamma} pour la preparation des echantillons, dosage du Plutonium par coulommetrie et double dilution isotopique, separation du Bore utilise dans certains cas pour la mesure des densites de neutrons integrees. On discute sur quelques exemples l'interpretation des mesures

  12. The Application of Various Nondestructive Testing Methods to Fuel Elements of the Orgel Type; Application des Differentes Methodes d'Essais Non Destructifs aux Elements Combustibles du Type Orgel; Primenenie razlichnykh nedestruktivnykh metodov ispytanij k toplivnym ehlementam tipa ''orgel''; Aplicacion de Distintos Metodos de Ensayo No Destructivo a los Elementos Combustibles de Tipo Orgel

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    Bonnet, P.; Jansen, J. [EURATOM, C.C.R., Ispra (Italy)

    1965-09-15

    . There is a device making it possible to examine four or six fuel elements simultaneously, or two or three separately. Standard radiographic tests. Particular stress is laid on the study of welds, and the limits of the experimental conditions in order to obtain good definition are given. In conclusion, the authors present a plan for a semi-industrial inspection system, describing the various possibilities for treatment, and try to define a general policy of non-destructive tests applied to fuel elements. (author) [French] Le memoire presente les differentes methodes employees pour la detection des defauts dans les tubes de gaine des elements combustibles (defauts de type dimensionnel ou defauts structuraux). Les auteurs evoquent egalement les tests finaux sur elements combustibles complets, en particulier: radiographie des soudures et tests d'etanchete. Ce sujet a deja ete partiellement traite. La recherche des caracteristiques dimensionnelles sur tube de gaine lisse en poudre d'aluminium frittee (SAP) a fait l'objet de recherches assez poussees. En particulier: 1. Mesures des diametres internes et externes par utilisation de capteurs pneumatiques et enregistrement des resultats; 2. Mesures des epaisseurs par utilisation, soit des ultrasons en methode de resonance, soit des rayons y (contrat EURATOM - Istituto Sperimentale Metalli Leggeri); 3. Controle de la fleche; 4. Tests sur tubes a ailettes. La detection des defauts sur tube de gaine lisse a egalement fait l'objet de travaux et un critere de rejet a ete adopte suivant l'utilisation future des tubes de gaines. a) La creation de defauts artificiels en fonction de la nocivite des defauts reels dans la poudre d'aluminium frittee est expliquee dans le memoire. Cette etude a montre, en effet, une grande sensibilite aux defauts du type longitudinal crees generalement lors de la transformation par de grosses inclusions. b) Tests par ultrasons. Defauts longitudinaux: Une comparaison entre la methode a deux capteurs et la

  13. Contribution to the study of can deformations in the fuel elements of gas-graphite reactors during thermal cycling; Contribution a l'etude des deformations des gaines des elements combustibles de reacteur graphite-gaz au cours du cyclage thermique

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    Gauthron, M; Boudouresques, B; Delpeyroux, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The cans of fuel cartridges used in reactors of the gas-graphite type have either longitudinal fins of variable thickness, short herring-bone fins, or else a mixture of the two. An important test of the strength of these cartridges is their behaviour during thermal cycling carried out in cells reproducing in-pile conditions. It has been observed during with rapid cooling that there occurs a shortening at the base of the fins which can be accompanied in particular by a compression effect at the fin type, which has a tendency to curl, and by a tractive force acting on the body of the can at the ends of the longitudinal fins; this last phenomenon can result in a fracturing of the welds at the extremities or of the ends of the cartridge. This report presents first of all the way in which the stress diagram can be drawn for a can touching the fuel, and then the effect of the ratchet along a fin fixed to a bar with or without grooves. Finally the importance is shown of the test cycling variables (temperature, heating and cooling rates). (authors) [French] Les gaines des cartouches combustibles des reacteurs de la filiere graphite-gaz comportent soit des ailettes longitudinales plus ou moins epaisses, soit de courtes ailettes a chevrons, soit un ensemble des deux. Un test important de la tenue des cartouches, est la tenue au cyclage thermique en cellule pour reproduire le comportement en pile. On a observe au cours des cyclages a refroidissement rapide, un raccourcissement a la base des ailettes qui peut s'accompagner notamment d'une mise en compression du sommet de l'ailette qui a tendance a friser, et d'une traction exercee sur le corps des gaines au bout des ailettes longitudinales; ce dernier phenomene peut se traduire par des ruptures de soudures d'extremites ou des parties terminales de la cartouche. Ce rapport presente d'abord la maniere dont peut etre trace le diagramme des contraintes dans une gaine liee au combustible, puis l'effet du rochet le long d

  14. Study of a device for the direct measurement of the fission gas pressure inside an in-pile fuel element; Etude d'un dispositif pour la mesure directe de la pression des gaz de fission a l'interieur d'un element combustible en pile

    Energy Technology Data Exchange (ETDEWEB)

    Lavaud, B; Uschanoff, S [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The fission gas pressure inside a fuel element made of a refractory fuel constitutes an important limiting factor for the burn-up. Although it is possible to calculate approximately the volume of gas produced outside the fuel during its life-time; it is nevertheless very difficult to evaluate the pressure since the volume allowed to the fission gases, as well as their temperature are known only very approximately. This physical value, which is essential for the technologist, can only be known by direct in-pile measurement of the pressure. The report describes the equipment which has been developed for this test. (authors) [French] La pression des gaz de fission a l'interieur d'un element combustible a combustible refractaire constitue une des limitations importantes du taux de combustion. Si on peut approcher par calcul la determination du volume, des gaz degages hors du combustible au cours de sa vie, il est par contre tres difficile d'evaluer la pression car le volume alloue aux gaz de fission et leur temperature sont tres mal connus. Cette donnee essentielle pour le technologue ne peut etre atteinte que par une mesure directe en pile de la pression. Le rapport decrit l'appareillage qui a ete mis au point pour cet essai. (auteurs)

  15. Recovery of trans-plutonium elements; Recuperation des elements transplutoniens

    Energy Technology Data Exchange (ETDEWEB)

    Espie, J Y; Poncet, B; Simon, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1970-07-01

    The object of this work is to study the recovery of americium and curium from the fission-product solution obtained from the processing of irradiated fuel elements made of natural metallic uranium alloyed with aluminium, iron and silicon; these elements have been subjected to an average irradiation of 4000 MW days/ton in a gas-graphite type reactor having a thermal power of 3.7 MW/ton of uranium. The process used consists of 3 extraction cycles and one americium-curium separation: - 1) extraction cycle in 40 per cent TBP: extraction of actinides and lanthanides; elimination of fission products; - 2) extraction cycle in 8 per cent D2EHPA: decontamination from the fission products, decontamination of actinides from lanthanides; - 3) extraction cycle in 40 per cent TBP: separation of the complexing agent and concentration of the actinides; - 4) americium-curium separation by precipitation. (authors) [French] Cette etude a pour objet, la recuperation de l'americium et du curium de la solution de produits de fission provenant du traitement de combustibles irradies a base d'uranium naturel metallique allie a l'aluminium, le fer, et le silicium, et ayant subi une irradiation moyenne de 4000 MWj/t dans une pile du type graphite-gaz, dont la puissance thermique est de 3.7 MW/t d'uranium. Le procede utilise comprend 3 cycles d'extraction et une separation americium-curium: - 1. cycle d'extraction dans le TBP a 40 pour cent: extraction des actinides et des lanthanides, elimination des produits de fission; - 2. cycle d'extraction dans le D2EHPA a 8 pour cent: decontamination en produits de fission, decontamination des actinides en lanthanides; - 3. cycle d'extraction dans le TBP a 40 pour cent: separation du complexant et concentration des actinides; - 4. separation americium-curium par precipitation. (auteurs)

  16. Optimization of fuel cycles: marginal loss values; Optimisation des cycles de combustibles: valeurs marginales des pertes

    Energy Technology Data Exchange (ETDEWEB)

    Gaussens, J [Commissariat a l' Energie Atomique, 75 - Paris (France); Lasteyrie, B de; Doumerc, J [Compagnie pour l' Etude et la Realisation de Combustibles Atomiques, 75 - Paris (France)

    1965-07-01

    comme definitivement perdue, alors que le reste pourrait etre recupere et recycle. Le cout eleve des pertes, recyclees ou non, d'autant plus eleve que l'uranium est plus enrichi, exige qu'il en soit tenu compte dans l'optimisation generale des cycles de combustible. Il importe donc de determiner leur niveau le plus souhaitable economiquement, aux diverses etapes d'elaboration du combustible nucleaire. Mais en France et dans d'autres pays, la production de matieres fissiles est geree par l'Etat, tandis que la fabrication de l'element combustible est effectuee par l'industrie privee. Les criteres d'optimisation et l'interet economique accorde aux pertes sont donc differents pour les deux parties de la chaine de fabrication. Pour tenter neanmoins d'atteindre un optimum conforme a l'interet collectif sans intervenir dans la politique de prix de l'entreprise, on peut utiliser la propriete des couts marginaux d'etre egaux entre eux a l'optimum, pour un volume de production donne. On peut donc ajuster le niveau des pertes pour realiser cette egalite des couts marginaux dont le calcul est plus facile a obtenir de la firme que la justification des prix eux-memes. On s'apercoit d'ailleurs que, bien qu'axee essentiellement sur les pertes, cette analyse globale peut conduire a une meilleure utilisation d'autres facteurs de production. On donne un expose theorique et des exemples pratiques de cette methode d'optimisation economique dans le cadre de la fabrication d'elements combustibles destines a des reacteurs du type: uranium naturel, moderes au graphite et refroidis par le gaz carbonique. (auteurs)

  17. The Non-Destructive Testing of Fuel Elements and Their Components for the United Kingdom Power-Reactor Development Programme; Controle Non Destructif des Elements Combustibles et de Leurs Parties Constitutives dans le Cadre du Programme de Developpement des Reacteurs de Puissance au Royaume-Uni; Nedestruktivnoe ispytanie teplovydelyayushchikh ehlementov i ikh komponentov dlya osushchestvleniya programmy soedinennogo korolevstva po razrabotke ehnergeticheskikh reaktorov; Ensayo No Destructivo de Elementos Combustibles y sus Componentes, en el Marco del Programa de Reactores de Potencia del Reino Unido

    Energy Technology Data Exchange (ETDEWEB)

    Mann, C. A.; Campsie, I. C. [U.K.A.E.A., Reactor Fuel Element Laboratories, Springfields, Salwick, Preston, Lancs. (United Kingdom)

    1965-10-15

    and the ends closed. In addition, the integrity of end closures is established, by radiography. Multiple exposures are commonly made to examine the whole of circumferential weld adequately. The disposition of the fuel can also be recorded accurately by using a panoramic technique. The use of colour radiography is also discussed. Pins are normally tested for leakage after filling with helium, using a mass-spectrometer leak detector. Pins not filled with helium may be tested using a ''back-pressurizing'' technique. Conventional ''probing'' and ''sniffing'' methods are used when it is desirable to locate the sites of leaks. The bubble test in liquids is also used, as a cheap and simple test. The use of krypton-85 as a tracer gas is discussed. (author) [French] Les auteurs decrivent les methodes d'essai que les laboratoires charges des elements combustibles ont elaborees dans le cadre du programme etabli par le des reacteurs> en vue de mettre au point des aiguilles de combustible pour diverses filieres de reacteurs. Ces aiguilles sont contenues dans des gaines de 5 a 15 mm de diametre, les materiaux utilises etant des aciers inoxydables et des alliages de zirconium, a) Detection de defauts dans les gaines. Examen par ultrasons a l'aide de deux traducteurs immerges. Les tubes sont animes d'un mouvement helicoidal rapide dans un reservoir fixe. Chaque signal de defaut est verifie et enregistre. Pour regler le dispositif et verifier sa stabilite, on utilise comme temoins des fentes'pratiquees a l'arc a la surface des tubes. Dans certains cas, on a egalement recours au controle par courants de Foucault. Les auteurs decrivent deux procedes: l'un, a debit rapide, est fonde sur un systeme de bobines encerclant le tube; l'autre, a exploration heliccfldale, utilise une bobine se deplacant le long du tube. Les signaux fournis par un circuit a pont sont selectionnes selon la phase et filtres, pour des frequences de 30 a 60 kHz. b) Controle des dimensions de tubes et de

  18. Optimization of fuel cycles: marginal loss values; Optimisation des cycles de combustibles: valeurs marginales des pertes

    Energy Technology Data Exchange (ETDEWEB)

    Gaussens, J. [Commissariat a l' Energie Atomique, 75 - Paris (France); Lasteyrie, B. de; Doumerc, J. [Compagnie pour l' Etude et la Realisation de Combustibles Atomiques, 75 - Paris (France)

    1965-07-01

    'uranium doit etre consideree comme definitivement perdue, alors que le reste pourrait etre recupere et recycle. Le cout eleve des pertes, recyclees ou non, d'autant plus eleve que l'uranium est plus enrichi, exige qu'il en soit tenu compte dans l'optimisation generale des cycles de combustible. Il importe donc de determiner leur niveau le plus souhaitable economiquement, aux diverses etapes d'elaboration du combustible nucleaire. Mais en France et dans d'autres pays, la production de matieres fissiles est geree par l'Etat, tandis que la fabrication de l'element combustible est effectuee par l'industrie privee. Les criteres d'optimisation et l'interet economique accorde aux pertes sont donc differents pour les deux parties de la chaine de fabrication. Pour tenter neanmoins d'atteindre un optimum conforme a l'interet collectif sans intervenir dans la politique de prix de l'entreprise, on peut utiliser la propriete des couts marginaux d'etre egaux entre eux a l'optimum, pour un volume de production donne. On peut donc ajuster le niveau des pertes pour realiser cette egalite des couts marginaux dont le calcul est plus facile a obtenir de la firme que la justification des prix eux-memes. On s'apercoit d'ailleurs que, bien qu'axee essentiellement sur les pertes, cette analyse globale peut conduire a une meilleure utilisation d'autres facteurs de production. On donne un expose theorique et des exemples pratiques de cette methode d'optimisation economique dans le cadre de la fabrication d'elements combustibles destines a des reacteurs du type: uranium naturel, moderes au graphite et refroidis par le gaz carbonique. (auteurs)

  19. Checking the sealing of fuel elements by helium sweating - case of the reactors G2 (1960); Controle de l'etancheite des elements combustibles par ressuage d'helium - cas du reacteur G2 (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, B; D' Orival, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Choumoff, S [Compagnie Francaise Thomson-Houston, 75 - Paris (France)

    1960-07-01

    The G2 slug is a welded, hermetically sealed unit; the seal is checked by placing the fuel element in a helium atmosphere under pressure, then measuring the quantity of helium it releases in a vessel under vacuum. The theoretical aspect and the conditions of industrial application are reviewed, and the installations described. (author) [French] La cartouche G2 se presente comme un ensemble soude, hermetique; le controle d'etancheite s'effectue en immergeant l'element combustible dans une atmosphere d'helium sous pression puis en mesurant la quantite d'helium qu'il restitue dans une enceinte sous vide. L'aspect theorique et les conditions d'exploitation industrielle sont evoques et les installations decrites. (auteur)

  20. Design of the Small Rods Forming the Fuel Element of the First Charge of the EL4 Reactor. Cladding Problems; Etude des crayons constituant l'element combustible du premier jeu d'EL4 - probleme de la gaine; Problema pokrytiya nebol'shikh steeknej, obrazushchikh toplivnyj ehlement pervoj zagruzki reaktora EL.4; Estudio de las barras que constituyen los elementos combustibles de la primera carga del reactor EL4 - el problema de las vainas

    Energy Technology Data Exchange (ETDEWEB)

    Bailly, H.; Ringot, C.; Weisz, M. [Centre d' Etudes Nucleaires de Saclay (France)

    1963-11-15

    The fuel element for the first charge of EL4 makes use of stainless steel cans. The grade of steel chosen and the can thickness depend on the corrosion resistance and mechanical strength required. The operating stresses and temperatures are such that fabrication of a can lasting throughout the life of the fuel element calls for a highly resistant grade of steel, of thickness greater than 0.5 mm. When the can bears on the fuel as a result of creep, deformation in diametrical clearance may lead to ovalization and folding, while deformation in longitudinal clearance may cause buckling of the can. Numerous tests have been carried out on cans of thickness 0.3 and 0.4 mm to determine type of deformation as a function of clearance. To be certain of avoiding ovalization with the thicknesses proposed and to keep the internal temperature of the fuel as low as possible, the clearance must be reduced to zero in fabrication. (author) [French] L'element combustible du premier jeu EL4 utilise des gaines en acier inoxydable. Le choix de la nuance et de l'epaisseur de la gaine est lie a des considerations de tenue a la corrosion et de tenue mecanique. Les contraintes et les temperatures d'utilisation ne permettent pas de concevoir une gaine resistante pendant toute la vie de l'element combustible a moins d'utiliser une nuance tres resistante et d'epaisseur superieure a 0,5 mm. On admet que la gaine s'applique par fluage sur le combustible: la deformation dans les jeux diametraux peut conduire a la formation d'une ovalisation et d'un pli; la deformation dans les jeux longitudinaux peut conduire a des flambages de la gaine. De nombreux essais ont ete realises sur des gaines d'epaisseurs 0,3 et 0,4 mm pour connaitre le mode de deformation en fonction des jeux. Pour etre certain de ne jamais avoir d'ovalisation avec les epaisseurs envisagees, et pour avoir la temperature a coeur du combustible la plus basse possible, on est conduit a reduire a zero le jeu en fabrication. (author

  1. Magnox Fuel Cycles; Cycles des combustibles gaines de magnox; Toplivnye tsikly magnoks; Ciclos de combustible magnox

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, A. [United Kingdom Atomic Energy Authority, Risley, Warrington, Lancs (United Kingdom)

    1963-10-15

    The interaction between reactivity flux and temperature distributions and irradiation patterns caused by different refuelling policies is considered and present calculation methods outlined. Various refuelling schemes for both batch and continuous discharge systems are compared. The problem of the efficient irradiation of the first charge is considered together with delayed onset refuelling and shuffling schemes. The economic advantages and problems of using non-natural uranium in flattened reactors are discussed. The practical consideration of on-load refuelling schemes on new reactors are considered and reference is made to the experience gained on Bradwell and Berkeley. The effect of the variation of fuel cost and endurance on fuel-cycle economics is outlined. (author) [French] L'auteur etudie en premier lieu l'interaction entre les distributions de la temperature du flux et de la reactivite, d'une part, et le regime de l'irradiation, d'autre part, dans le cas de differents programmes de rechargement du combustible et il decrit brievement les methodes de calcul actuelles. Il compare ensuite differents programmes de rechargement du combustible pour le dechargement par lots et le dechargement continu. Il etudie le probleme de l'irradiation effica ce de la premiere charge dans le cadre de programmes de remplacement et de deplacement des cartouches a action retardee. Il analyse les avantages economiques de l'utilisatio n d'uranium non naturel dans les reacteurs a flux aplati et les problemes qu'elle pose. Il examine les aspects pratiques des programmes de rechargement en marche pour les nouveaux reacteurs, en se referant a l'experience acquise au moyen des reacteurs de Bradwell et de Berkeley. Enfin, il decrit brievement les effets des variations du cout et de la resistance du combustible sur l'economie des cycles de combustible. (author) [Spanish] La memoria estudia la interaccion entre el flujo de reactividad y la distribucion de temperaturas, asi como los

  2. A Method of Identification and Inspection for Inventory Control of Irradiated Fuel Elements; Methode d'Identification et d'Inspection Permettant de Proceder a l'Inventaire des Elements Combustibles Irradies; Metod identifikatsii i proverki pri inventarnom kontrole obluchennykh toplivnykh ehlementov; Metodos de Identificacion e Inspeccion para el Control de las Existencias de Elementos Combustibles Irradiados

    Energy Technology Data Exchange (ETDEWEB)

    Kinderman, E. M.; Mills, J. S. [Stanford Research Institute, Menlo Park, CA (United States)

    1966-02-15

    The reactor discharge and irradiated fuel storage locations should be examined in any complete special nuclear materials inventory. They present, however, special physical difficulties to the auditor or inventory control manager. In these locations the distance between object and observer and the poor illumination and optical distortion caused by the shielding media (water, lead glass) contribute to the difficulties of materials inventory. In an attempt to overcome these difficulties and to provide a system for positive identification of reactor discharged fuel, we have developed a compact and convenient optical examination system utilizing a fixed examination station, a periscope, a telescope, and a camera. This system has been tested in a cobalt irradiation pool by examination of test coupons which were marked in various ways, and then treated in a hot, circulating water loop. In the test system, a water-filled periscope, 11-ft long, a catadioptric telescope placed 16 ft from the periscope, and a 35-mm camera for recording the observations were used. The telescope, camera and mountings are all readily portable since they weigh in total less than 22 lb and have maximum dimensions of 29 in. Photographic observations of test resolution charts in air 20 ft away from the object lens of the telescope have demonstrated that the system can resolve markings 22 {mu}m in width. This corresponds to a resolution of 0.8 second of arc. Tests performed on the water system have shown that resolution in this system is better than 50 {mu}m at 20 ft. This corresponds to a resolution of about 1 second of arc. It is clear that the resolution can never be better than the air path system. The present system used in an actual fuel inventory should adequately reproduce any inventory markings. (author) [French] Tout inventaire complet des matieres nucleaires speciales exige un controle au point de dechargement du reacteur et au point de stockage du combustible irradie. Or, ce controle pose

  3. Calculation of the working capital invested in fuel cycles and its interest charges (1963); Calcul des immobilisations financieres des cycles de combustible (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Gaussens, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    All the processes undergone by the nuclear material, including the various steps of fuel element manufacturing and of irradiated fuel reprocessing lead to working capital investments varying with the type of reactor, that must be taken into account in the kWh cost calculation. The author deals with a calculation method called: 'present worth method' and gives some examples concerning reactors the main fuel of which being either natural uranium or enriched uranium or plutonium. He especially points out the importance these investments may take in the case of fast breeder reactors. (author) [French] L'ensemble des etapes parcourues par la matiere fissile comprenant les divers stades d'elaboration des elements combustibles et de leur traitement apres irradiation, implique des immobilisations financieres tres differentes d'un type de reacteur a l'autre, dont il convient de tenir compte dans le calcul du cout du kWh. L'auteur expose une methode de calcul dite 'd'actualisation des couts' et donne quelques exemples relatifs aux reacteurs utilisant l'uranium naturel, l'uranium enrichi et le plutonium comme combustible principal. Il montre en particulier l'importance que peuvent avoir ces immobilisations dans le cas des reacteurs surregenerateurs. (auteur)

  4. Elemental analysis of combustion products by neutron activation

    International Nuclear Information System (INIS)

    Heft, R.E.; Koszykowski, R.F.

    1980-01-01

    This paper gives a brief description of the neutron activation analysis method, which is being used to determine the elemental profile of combustion products from coal-fired power plants, oil shale retorting, and underground coal gasification

  5. Recent developments in the field of refractory fuels; Developpements recents dans le domaine des combustibles refractaires

    Energy Technology Data Exchange (ETDEWEB)

    Accary, A; Delmas, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    or arc fusion). This latter method is based on fusion by electronic bombardment associated with the continuous casting. (authors) [French] L'effort des recentes annees au Commissariat a l'Energie Atomique dans le domaine des combustibles ceramiques a surtout porte sur le bi-oxyde d'uranium et les alliages uranium-carbone. Le bi-oxyde d'uranium est etudie dans l'optique de son utilisation comme combustible de la premiere charge d'EL 4, dans laquelle on impose au point le plus charge une conductibilite thermique integree de 29 W/cm pour une temperature de surface de 750 C environ. On s'est specialement preoccupe de mettre en place un procede de preparation d'une poudre de bi-oxyde de bonnes caracteristiques et le frittage industriel de cette poudre, et d'evaluer les principales proprietes des corps obtenus en relation avec les conditions des corps obtenus en relation avec les conditions prevues de leur utilisation: - aspect de micro-structure et distribution des pores, - comportement mecanique et thermique en geometrie cylindrique, - controle de l'oxygene excedentaire dans les produits industriels, - compatibilite aux hautes temperatures avec les oxydes utilisables comme isolants thermiques, - comportement des produits de fission gazeux a haute temperature apres irradiation ou au cours de l'irradiation. Dans le cas des carbures d'uranium, notre but a ete de determiner les conditions de fabrication industrielle d'un combustible satisfaisant de composition voisine de UC. Ceci nous a conduits a entreprendre un certain nombre d'etudes fondamentales Sur le domaine d'existence de UC non stoechiometrique, - l'influence, sur les proprietes de UC, des elements O et N dissous dans ce materiau, - la compatibilite des alliages uranium-carbone avec differents materiaux de gaine metalliques ou ceramiques, - la corrosion des alliages uranium-carbone par H{sub 2}O et CO{sub 2}, - les methodes de preparation d'echantillons de haute purete, - les dispositifs d'irradiation en pile

  6. A Rapid-Insertion Control-Absorber Mechanism for Use in Hollow Fuel Elements; Mecanisme d'Insertion Rapide d'Absorbants pour Utilisation dans des Elements Creux; Mekhanizm bystrogo vvoda poglotitelya dlya ispol'zovaniya v polykh toplivnykh ehlementakh; Mecanismo para la Insercion Rapida de Absorbentes en Elementos Combustibles Huecos

    Energy Technology Data Exchange (ETDEWEB)

    King, E. S.F. [Atomic Energy Research Establishment Harwell, Berks. (United Kingdom)

    1964-06-15

    reglee avec une precision de 4 x 10{sup -3}cm et on peut le retirer a des vitesses de 0,04 cm/s'et 0,01 cm/s. Le mecanisme est constitue par un moteur a vernier qui entraihe une vis sans fin et eleve ou abaisse un obturateur cylindrique adapte a la protection a sa base d'un electro-aimant qui soutient un tube absorbant. Il y a un espace important autour du tube absorbant, qui tombe en chute libre (il rencontre seulement la resistance visqueuse du ralen- tisseur/refroidisseur) jusqu'a ce qu'il soit arrete dans sa chute par une barre centrale passant a travers la vis sans fin et aboutissant a un amortisseur a ressort circulaire situe au sommet du mecanisme. Apres la chute du tube absorbant, le moteur fait descendre rapidement l'obturateur dans lequel on engage de nouveau le tube. La dimension du mecanisme est comprise dans les dimensions d'ensemble de l'element et on peut le sortir du reacteur en meme temps que l'element ou separement, au moyen de la bouteille de dechargement du combustible [Spanish] El autor describe las caracteristicas tecnicas y funcionales de un mecanismo de mando para absorbentes de control, de insercion rapida, aplicable a los elementos combustibles huecos, verticales, de los reactores de ensayo de materiales de tipo DIDO, cuyo flujo termico es de 10{sup 14} n/cm{sup 2} s. La aceleracion descendente inicial del absorbente es la debida a la gravedad y la carrera total, de 61 cm, se cumple en 0,4 s. El intervalo de disparo del iman es de 5 ms. El absorbente pesa 7 kg, tiene una superficie efectiva de 1000 cm{sup 2} de Cd y una capacidad de regulacion del 3% de la reactividad. Su posicion puede fijarse con una precision de 4 x 10{sup -3}cm y la velocidad de extraccion varia entre 0,04 cm/s y 0,01 cm/s. El mecanismo consta de un motor de avance a vernier que acciona un tornillo de guia y puede elevar o bajar un obturador blindado cilindrico de ajuste estricto que lleva un electroiman en el extremo inferior y sostiene el absorbente tubular. La luz radial

  7. Development and testing of the EDF-2 reactor fuel element; Essais et mise au point de l'element combustible pour le reacteur EDF-2

    Energy Technology Data Exchange (ETDEWEB)

    Delpeyroux, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Furhmann, R [Societe Industrielle de Combustible Nucleaire (France)

    1964-07-01

    rassemble les etudes qui ont ete necessaires pour mener a bien la definition de l'element combustible EdF 2. Apres un bref rappel des caracteristiques du reacteur EdF 2 et des options preliminaires ayant permis de fixer un avant-projet d'element combustible, on aborde les etudes proprement dites: - Etudes uranium: essais de passage d'une couronne interne du tube en phase {beta}, flechage du tube sous l'action d'une force concentree, soudage des pastilles d'extremites et verification de leur etancheite. La tenue du tube a l'ecrasement et la resistance des pastilles a l'enfoncement sous l'action de la pression externe sont etudiees en detail dans un autre rapport CEA - Etudes gaine: rappel des conditions de fabrication et verification de l'etancheite de la gaine, tenue des ailettes au fluage sous l'action du courant gazeux - Etudes d'extremites: fluage en compression et soudage des bouchons a la gaine. - Etudes cartouche: determination des caracteristiques des gorges d'ancrage gaine-combustible et des conditions de gainage, verification de la tenue au cyclage thermique de l'element combustible, determination de la chute de temperature au contact gaine-combustible traitee en detail dans un autre rapport CEA, - Etudes de l'ensemble: les etudes se rapportant a la chemise de graphite, au support et aux vibrations de la cartouche ont ete traitees par le service des Etudes Mecaniques et Thermiques (Section de Mecanique), Dans ce domaine, la Section d'Etude d'Elements Combustibles a etudie la tenue des centreurs sous l'action du courant gazeux. L'aboutissement des etudes est constitue par le dessin de l'element combustible, le schema de fabrication et les normes de fabrication. La validite de l'ensemble de ces essais hors pile sera confirmee par des assais en pile qui sont en cours et par l'irradiation des elements dans le reacteur EdF 2 lui-meme. En conclusion, on donne l'orientation des etudes pour l'amelioration de l'element combustible et la definition d'un element combustible

  8. Study of the thermal drop at the uranium-can interface for fuel elements in gas-graphite reactors; Etude de la chute thermique au contact uranium-gaine pour des elements combustibles de reacteur de la filiere graphite-gaz

    Energy Technology Data Exchange (ETDEWEB)

    Faussat, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Levenes, G; Michel, M [Societe Industrielle de Combustible Nucleaire (France)

    1964-07-01

    The report reviews the tests now under way at the CEA, for determining the thermal contact resistance at the uranium-can interface for fuel elements used in gas-graphite type reactors. These are laboratory tests carried out with equipment based on the principle of a heat flow across a stack of test pieces having planar contact surfaces. The following points emerge from this work: - for a metallic uranium element canned in magnesium, of the type G-2 or EDF-2, a value of 0.2 deg C/W/cm{sup 2} seems reasonable for can temperatures of 400 deg C and above. - this value is independent of the micro-geometric state of the uranium surface in a range of roughness which easily includes those observed on tubes and rods produced industrially. - for the internal cans of elements cooled internally and externally, the value of the contact resistance for temperatures of under 400 deg C as a function of the stresses in the can has not yet been measured exactly. (authors) [French] Le rapport fait le point des essais actuellement en cours au CEA pour determiner la resistance thermique de contact uranium-gaine pour des reacteurs de la filiere graphite-gaz. Ces essais sont effectues en laboratoire sur des appareils bases sur le principe d'une circulation de flux de chaleur a travers un empilement d'eprouvettes dont les faces en contact sont planes. De l'etude, il ressort essentiellement que: - pour un element a uranium metallique et gaine de magnesium type G-2 ou EdF-2, on peut admettre la valeur de 0,2 deg C/W/cm{sup 2} pour des temperatures de gaines de 400 deg C et plus. - cette valeur ne depend pas de l'etat de surface microgeometrique de l'uranium pour un domaine de rugosites couvrant largement celles que l'on observe sur des tubes et barreaux fabriques en serie. - pour les gaines internes d'elements a refroidissement interne et externe la valeur de la resistance de contact reste a preciser pour les temperatures inferieures a 400 deg C, en fonction des contraintes existant dans les

  9. Elemental analysis of Kuwaiti petroleum and combustion products

    Energy Technology Data Exchange (ETDEWEB)

    Reid, J.S.; Cahill, T.A.; Gearhart, E.A.; Flocchini, R.G. (California Univ., Davis, CA (United States). Crocker Nuclear Lab.); Schweitzer, J.S.; Peterson, C.A. (Schlumberger-Doll Research Center, Ridgefield, CT (United States))

    1993-03-01

    Crude oil from eight Kuwaiti fields and aerosols generated by their combustion in the laboratory have been analyzed by composition and particulate size. Liquid petroleum and petroleum combustion products were subjected to elemental analysis by proton induced x-ray techniques and by x-ray fluorescence techniques. The mean sulfur content of the burning wells was weighted by their production rates to obtain the mean sulfur content of the burning oil, 2.66%. The liquid samples were also analyzed by neutron activation analyses. Results show that Kuwaiti oil and smoke aerosols from laboratory combustion generally contain very low amounts of chlorine, contrary to what is found in airborne samples above Kuwait. Trace element signatures were developed to aid in tracing smoke from the oil fires. (Author).

  10. Partitioning of elements during coal combustion and leaching experiments

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wen-feng; Qin Yong; Song Dang-yu; Wang Jun-yi [China University of Mining & Technology, Xuzhou (China). School of Resources and Earth Science

    2009-04-15

    The mineral component and content of sulfur and 42 major and trace elements of the feed coal, fly and bottom ashes collected from Shizuishan coal-fired power plant, Ningxia, China were analyzed using AFS, INAA, ICP-MS, ICP-AES, XRD. Based on the coal combustion and leaching experiments, the partitioning of these elements during coal combustion and the leaching behavior of the 11 potentially hazardous elements, including As, Cd, Co, Cr, Hg, Mo, Ni, Pb, Se, Th and U were investigated. The results show that the distribution of elements in the fly and bottom ashes is controlled by their volatilities and modes of occurrence in the coal. The degree of volatilization of elements may be mainly associated with boiling/melting points of these elements and their compounds. The elements easily volatilized, organically bound or associated with sub-micrometer and nano minerals (e.g. Al and Na) tend to be enriched in the fine fractions of fly ash, and most elements do not vaporize which are approximately equally partitioned in the fly and bottom ashes. The emission rates of As, Cr, K, Mg, Mn, Mo, Pb, Sb, and Zn are notably influenced by the temperature ranging from 877 to 1300{sup o}C. The leaching behavior of elements depend significantly on their geochemical properties and modes of occurrence. The elements with a low degree of volatilization are not easily leached, while volatile elements easily leached under the acid conditions. Arsenic, B Br, Cd, Cu, Hg, Pb, S, Sb and Se show a higher emission rate during coal combustion, and the leached concentrations of Cd, Co, Mo, Ni and U in the acid media exceed their limited concentrations recommended in relevant environment quality standards for water, which will harm the environment. 32 refs., 4 figs., 4 tabs.

  11. Cost of transporting irradiated fuels and maintenance costs of a chemical treatment plant for irradiated fuels; Cout de transport des combustibles irradies et cout d'entretien d'une usine de traitement chimique des combustibles irradies

    Energy Technology Data Exchange (ETDEWEB)

    Sousselier, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    other plants, an attempt has been made to express the maintenance costs as a percentage of the investments corresponding to each of the sections considered. The unequal aspect of maintenance in a plant of this type is demonstrated, this being due particularly to the inaccessibility of most of the equipment during operation. Finally some conclusions are drawn on what the maintenance costs could be and the means of reducing them in future plants. (author) [French] Le cout du cycle des combustibles a fait l'objet de nombreuses etudes mais beaucoup d'entre elles sont basees sur des etudes a priori et sont donc plus ou moins sujettes a caution. C'est ainsi que dans la partie ayant trait au traitement des combustibles irradies, des elements importants du cout n'ont que rarement ete precises a la suite d'experiences pratiques: le cout du transport des combustibles eux-memes et le cout d'entretien de l'usine. Les etudes relatives au cout du transport sont generalement basees sur des calculs faits a partir de donnees un peu arbitraires. Les etudes qui ont ete faites en France pour le transport d'uranium irradie entre les reacteurs EdF de Chinon et l'usine de retraitement de La Hague et l'uranium irradie des reacteurs de recherches jusqu'aux usines de retraitement etrangeres sont exposees et montrent qu'il a ete possible d'arriver a des types de chateaux de transport et des modalites d'expedition qui permettent de diminuer les couts dans des proportions tres importantes. Ceci a pu etre obtenu soit en combinant les transports par rail et par route soit par l'augmentation des capacites unitaires des chateaux de transport: on cite le cas d'un chateau de transport pour element des piles piscines qui est capable de transporter un coeur complet d'une pile a la fois entrainant une reduction substantielle du cout. Les etudes concernant les couts d'entretien d'usines de retraitement sont encore plus rares, or, dans les usines a entretien direct, ces couts sont une fraction non negligeable

  12. Combustion chemistry and formation of pollutants; Chimie de la combustion et formation des polluants

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    This book of proceedings reports on 7 papers on combustion chemistry and formation of pollutants presented during the workshop organized by the `Combustion and Flames` section of the French society of thermal engineers. The chemistry of combustion is analyzed in various situations such as: turbojet engines, spark ignition engines, industrial burners, gas turbines etc... Numerical simulation is used to understand the physico-chemical processes involved in combustion, to describe the kinetics of oxidation, combustion and flame propagation, and to predict the formation of pollutants. (J.S.)

  13. L'évolution des combustibles pour moteurs thermiques Evolution of Fuels for Thermal Engines

    Directory of Open Access Journals (Sweden)

    Balaceanu J. C.

    2006-11-01

    Full Text Available Depuis la crise pétrolière, l'accroissement des prix et les craintes de pénurie ont conduit à adapter les moteurs aux combustibles disponibles. Si la situation apparaît comme moins tendue, l'industrie des machines thermiques, qui pendant longtemps a eu comme partenaire une industrie du pétrole très sûre, se trouve cependant confrontée à un marché des combustibles incertain dans son ravitaillement et surtout dans ses prix. Les progrès des moteurs diesel et des turbines à gaz, dûs à une meilleure adaptation à leur usage et aussi à l'évolution de la technologie, supposent que les combustibles n'apporteront aucune contrainte majeure en quantité ou en qualité. La modification des usages dévolus désormais au pétrole entraînera une réduction de la coupe lourde et un raffinage plus profond des bruts avec en particulier un développement du craquage catalytique et de la viscoréduction. Or, ces différentes opérations de conversion peuvent conduire à une détérioration de la qualité des combustibles moins grave pour le gazole que pour le fuel lourd. Dans les différents domaines impliqués, les parades technologiques sont en cours de développement. L'industrie des machines thermiques, qui poursuit l'amélioration des engins, et l'industrie du pétrole, qui recherche une réduction des prix des combustibles, sont donc conduites à un compromis optimal auquel elles ne peuvent accéder efficacement qu'en définissant les règles du jeu c'est-à-dire des spécifications internationales rigoureuses des combustibles. Since the oil crisis, the increase in prices and fears of a shortage have led to the adapting of engines to what fuels are available. Whereas the situation now seems somewhat less tense, the thermal machinery industry, which for a long time had a very reliable petroleum industry as its partner, nonetheless finds itself confronted with an uncertain fuel market with regard to supplies and especially to prices. Progress

  14. Large eddy simulation and combustion instabilities; Simulation des grandes echelles et instabilites de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Lartigue, G.

    2004-11-15

    The new european laws on pollutants emission impose more and more constraints to motorists. This is particularly true for gas turbines manufacturers, that must design motors operating with very fuel-lean mixtures. Doing so, pollutants formation is significantly reduced but the problem of combustion stability arises. Actually, combustion regimes that have a large excess of air are naturally more sensitive to combustion instabilities. Numerical predictions of these instabilities is thus a key issue for many industrial involved in energy production. This thesis work tries to show that recent numerical tools are now able to predict these combustion instabilities. Particularly, the Large Eddy Simulation method, when implemented in a compressible CFD code, is able to take into account the main processes involved in combustion instabilities, such as acoustics and flame/vortex interaction. This work describes a new formulation of a Large Eddy Simulation numerical code that enables to take into account very precisely thermodynamics and chemistry, that are essential in combustion phenomena. A validation of this work will be presented in a complex geometry (the PRECCINSTA burner). Our numerical results will be successfully compared with experimental data gathered at DLR Stuttgart (Germany). Moreover, a detailed analysis of the acoustics in this configuration will be presented, as well as its interaction with the combustion. For this acoustics analysis, another CERFACS code has been extensively used, the Helmholtz solver AVSP. (author)

  15. Zircaloy-sheathed element rods fitted with thermo-couples; Barre combustible a thermocouple gainee de zircaloy

    Energy Technology Data Exchange (ETDEWEB)

    Bernardy de Sigoyer, B; Jacques, F; Thome, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    In order to carry out thermal conductivity measurements on UO{sub 2} in conditions similar to those under which fuel rods are used, it was necessary to measure the temperature at the interior of a fuel element sheathed in zircaloy. The temperatures are taken with Thermocoax type thermocouples, that is to say fitted with a very thin sheath of stainless steel or Inconel. It is known also that fusion welding of zircaloy onto stainless steel is impossible and that high temperature welded joints are very difficult because of their aggressiveness. The technique used consists in brazing the thermocouples to relatively large stainless steel parts and then joining these plugs by electron bombardment welding to diffused stainless steel-zircaloy couplings. The properties of these diffused couplings and of the brazed joints were studied; the various stages in the fabrication of the containers are also described. (authors) [French] Pour des mesures de conductivite thermique de l'UO{sub 2} dans des conditions voisines du fonctionnement des barres combustibles, il s'agissait de mesurer la temperature a l'interieur d'un element combustible gaine de zircaloy. Les prises de temperature sont faites par thermocouples du type Thermocoax, c'est-a-dire pourvu d'une gaine tres mince en inox ou inconel. Par ailleurs on sait que le soudage par fusion du zircaloy sur l'inox est impossible et que les brasures a haute temperature sont difficiles car tres agressives. La technique utilisee consiste a braser les thermocouples sur des pieces en inox relativement massives et de rapporter par soudage au bombardement electronique ces bouchons sur des raccords diffuses zircaloy-inox. Les proprietes de ces raccords diffuses et celles de joints brases ont ete etudiees; on expose egalement les diverses etapes de fabrication des containers. (auteurs)

  16. Coextrusion applied to the construction of fuel elements in solid or powder form; Coextrusion appliquee a la realisation d'elements combustibles massifs ou disperses

    Energy Technology Data Exchange (ETDEWEB)

    Montagne, R; Meny, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    In this issue is described, in the first part, a realisation process of fuel elements for nuclear reactors. A contact as good as possible is achieved between the fuel and the can by both elements simultaneous extrusion. In this way a real weld is work out between the two metals. This weld can be improved by a thermic treatment that bring a diffusion. In this article are described the test carried out on these co extruded elements. In the second part, the fabrication of dispersed fuel elements studied: a 30 per cent weight U uranium-aluminium alloy is used, valuable with 20 per cent enriched uranium. The dimensions of the fuel element have been fixed at: external diameter: 30 mm, internal diameter: 24 mm, length of the core: 300 mm, thickness of the can: 0,4 mm. The method of fabrication is pressing of the mixed uranium and aluminium powders in an aluminium can, and extrusion at 500 deg. C.; one end is directly canned by extrusion and the other by welding of an aluminium plug. The results of the first test are described. (author) [French] Dans ce memoire est decrit, en premiere partie, un procede d'obtention d'elements combustibles pour reacteurs atomiques. Un contact aussi bon que possible est realise entre le combustible et la gaine grace au filage simultane des deux elements. Une veritable soudure est ainsi realisee entre les deux metaux. Celle-ci peut ensuite etre amelioree par un traitement thermique provoquant une diffusion. Les essais effectues sur ces elements coextrudes sont decrits dans cet article. Dans une deuxieme partie, la fabrication d'elements combustibles disperses est etudiee, avec un alliage uranium-aluminium a 30 pour cent en poids d'uranium, valable pour un enrichissement de l'uranium de 20 pour cent. Les dimensions des elements combustibles ont ete fixees a: diametre exterieur: 30 mm, diametre interieur: 24 mm, longueur du noyau: 300 mm, epaisseur de la gaine: 0,4 mm. La methode de fabrication est le pressage dans un pot en aluminium du

  17. The fuel element of the first charge for EL 4; presentation, main problems arising in the research, production problems; L'element combustible du 1. jeu de EL 4; presentation, problemes essentiels poses par l'etude, problemes de fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Ringot, C; Bailly, H; Bujas, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The fuel element making up the first charge for EL-4 is made of slightly enriched uranium oxide canned in stainless steel. This fuel element makes it possible to operate the reactor in the safest conditions awaiting the development of the fuel which will be finally adopted; this will have a low absorption can: beryllium, or a zirconium copper alloy. The 500 mm assembly is made up of 19 small rods placed on 3 rings, inside a graphite jacket. The solution adopted was a solution using completely independent small rods. This report deals with possible problems resulting from their study and production. (authors) [French] L'element combustible du 1er jeu EL-4 est un element combustible a oxyde d'uranium legerement enrichi gaine d'acier inoxydable. C'est un element combustible permettant de faire fonctionner le reacteur EL 4 dans des conditions aussi sures que possible avant de mettre au point le combustible definitif qui sera a gaine peu absorbante: beryllium, ou alliage zirconium-cuivre. L'assemblage de longueur 500 mm est constitue de 19 crayons places sur 3 couronnes, a l'interieur d'une chemise de graphite. La solution adoptee a ete une solution a crayons independants les uns des autres. Ce rapport traite des problemes eventuels poses par leur etude et leur fabrication. (auteurs)

  18. Optimal sizes and siting of nuclear fuel reprocessing plants; Tailles et localisations optimales des usines de retraitement des combustibles nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Thiriet, L; Deledicq, A [Commissariat a l' Energie Atomique, Siege (France). Centre d' Etudes Nucleaires

    1967-07-01

    The expansion of a nuclear economy entails the development of fuel process and reprocessing plant programmes. The model proposed makes it possible to select the size, the site and the start-up schedule of the plants in such a way as to minimize the total freight and reprocessing costs. As an illustration, we have approached the problem of burnt natural uranium processing plants related to natural uranium-graphite as nuclear power stations. The sites and annual output of the reactors, the possible plant sites and cost functions (freight and reprocessing) are supposed to be known. The method consists in first approaching the process plant problem as a Dynamic Programming problem, increasing programme slices (total reactor output) being explored sequentially. When the quantities of burnt natural uranium to be reprocessed are fixed, the minimization of the transport cost is then also carried out as a dynamic programming problem. The neighbourhood of the optimum process cost is explored in order to find the minimum summation of a suboptimal processing cost and corresponding optimal transport cost. As the reprocessing problem can be represented on a sequential graph, in order to compute the sub-optima, we developed and used a 'reflexion algorithm'. The method can be interpreted as a general mechanism for determining the optimum when to a sequential dynamic problem (for example an equipment programme) is added a complementary problem (transport, for instance). It also makes it possible to estimate the economic losses which result from the choice of a non optimal policy for other than economic reasons. (author) [French] L'expansion de l'economie nucleaire se traduit par un developpement des programmes d'usines d'elaboration et de retraitement des combustibles. Le modele propose permet de choisir la taille, la localisation et la cadence de mise en service des usines de maniere a minimiser le total des frais de transport et de retraitement. A titre d'exemple nous avons

  19. Les piles à combustible. Bilan des travaux de recherches. Perspectives Fuel Cells. Review of Research. Outlook

    Directory of Open Access Journals (Sweden)

    Breelle Y.

    2006-11-01

    Full Text Available Cet article fait le point, sous forme résumée, des travaux de recherches et de développement menés par l'Institut Français du Pétrole (IFP depuis vingt ans dans le domaine des piles à combustible : sélection des filières directes conduisant au choix de la pile hydrogène-air basse température à électrolyte basique, mise au point des générateurs à hydrogène alimentés en méthanol. On présente les résultats obtenus et les conclusions des enquêtes effectués dans le domaine des groupes électrogènes et des applications spéciales, dans celui de la traction automobile et dans celui de la production massive d'électricité. This article reviews and sums up the research and development done by Institut Français du Pétrole (IFP in the last 20 years in the field of fuel cells, including the selection of direct methods leading to the choice of low-temperature basic-electrolyte hydrogen/air cells and the development of methanol-powered hydrogen generators. The results obtained are desceibed along with the conclusions of surveys made in the field of electric generators and special applications in the fields of automotive traction and massive electricity production.

  20. Kinetics of transuranium element oxidation-reduction reactions in solution; Cinetique des reactions d'oxydo-reduction des elements transuraniens en solution

    Energy Technology Data Exchange (ETDEWEB)

    Gourisse, D. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1966-09-01

    A review of the kinetics of U, Np, Pu, Am oxidation-reduction reactions is proposed. The relations between the different activation thermodynamic functions (compensatory effect, formal entropy of the activated complex, magnitude of reactions velocities) are considered. The effects of acidity, ionic strength deuterium and mixed solvents polarity on reactions rates are described. The effect of different anions on reactions rates are explained by variations of the reaction standard free energy and variations of the activation free energy (coulombic interactions) resulting from the complexation of dissolved species by these anions. (author) [French] Une revue systematique de la cinetique des reactions d'oxydo-reduction des elements U, Np, Pu, Am, en solution perchlorique est proposee. Des considerations relatives aux grandeurs thermodynamiques d'activation associees aux actes elementaires (effet de compensation, entropie standard des complexes actives, rapidite des reactions) sont developpees. L'influence de l'acidite, de la force ionique, de l'eau lourde et de la polarite des solvants mixtes sur la vitesse des reactions est decrite. Enfin l'influence des differents anions sur la vitesse des reactions est expliquee par les variations de l'enthalpie libre standard de la reaction et de l'enthalpie libre d'activation (travail des forces electrostatiques) resultant de la complexation des especes dissoutes dans la solution. (auteur)

  1. Kinetics of transuranium element oxidation-reduction reactions in solution; Cinetique des reactions d'oxydo-reduction des elements transuraniens en solution

    Energy Technology Data Exchange (ETDEWEB)

    Gourisse, D [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1966-09-01

    A review of the kinetics of U, Np, Pu, Am oxidation-reduction reactions is proposed. The relations between the different activation thermodynamic functions (compensatory effect, formal entropy of the activated complex, magnitude of reactions velocities) are considered. The effects of acidity, ionic strength deuterium and mixed solvents polarity on reactions rates are described. The effect of different anions on reactions rates are explained by variations of the reaction standard free energy and variations of the activation free energy (coulombic interactions) resulting from the complexation of dissolved species by these anions. (author) [French] Une revue systematique de la cinetique des reactions d'oxydo-reduction des elements U, Np, Pu, Am, en solution perchlorique est proposee. Des considerations relatives aux grandeurs thermodynamiques d'activation associees aux actes elementaires (effet de compensation, entropie standard des complexes actives, rapidite des reactions) sont developpees. L'influence de l'acidite, de la force ionique, de l'eau lourde et de la polarite des solvants mixtes sur la vitesse des reactions est decrite. Enfin l'influence des differents anions sur la vitesse des reactions est expliquee par les variations de l'enthalpie libre standard de la reaction et de l'enthalpie libre d'activation (travail des forces electrostatiques) resultant de la complexation des especes dissoutes dans la solution. (auteur)

  2. Release of Inorganic Elements during Wood Combustion. Release to the Gas Phase of Inorganic Elements during: Wood Combustion. Part 1: Development and Evaluation of Quantification Methods

    DEFF Research Database (Denmark)

    van Lith, Simone Cornelia; Alonso-Ramírez, Violeta; Jensen, Peter Arendt

    2006-01-01

    During wood combustion, inorganic elements such as alkali metals, sulfur, chlorine, and some heavy metals are partly released to the gas phase, which may cause problems in combustion facilities because of deposit formation and corrosion. Furthermore, it may cause harmful emissions of gases......) in this reactor, whereas methods B and C involved initial pyrolysis and combustion, respectively, of a large fuel sample (~5 kg) in a bench-scale fixed-bed reactor at 500 C. The methods were evaluated by comparing the data on the release of Cl, S, K, Na, Zn, and Pb from fiber board obtained by the three methods...

  3. Les méthodes thermiques de production des hydrocarbures. Chapitre 5 : Combustion "in situ". Pricipes et études de laboratoire Thermal Methods of Hydrocarbon Production. Chapter 5 : "In Situ" Combustion. Principles and Laboratory Research

    Directory of Open Access Journals (Sweden)

    Burger J.

    2006-11-01

    Full Text Available II existe plusieurs variantes de la combustion in situ, suivant le sens de déplacement du front de combustion, à co-courant ou à contre-courant, et suivant la nature des fluides injectés, air seul ou injection combinée d'air et d'eau. Les réactions de pyrolyse, d'oxydation et de combustion mises en jeu par ces techniques sont discutées, en particulier la cinétique des principaux mécanismes réactionnels, l'importance du dépôt de coke et l'exothermicité des réactions d'oxydation et de combustion. Les résultats d'essais de déplacement unidirectionnel du front de combustion dans des cellules de laboratoire sont présentés et discutés. Enfin on indique les conditions pratiques d'application des méthodes de combustion in situ sur champ. Possible variations of in situ combustion technique ore as follows : forward or reverse combustion depending on the relative directions of the air flow and the combustion front, dry combustion if air is the only fluid injected into the oil-bearing formation, or fixe/woter flooding if water is injected along with air. The chemical reactions of pyrolysis, oxidation and combustion involved in these processes are described. The kinetics of these reactions is discussed as well as fuel availability in forward combustion and the exothermicity of the oxidation and combustion reactions. The results obtained in the laboratory when a combustion front propagates in unidirectional adiabatic tells are described and discussed. This type of experimentation provides extensive information on the characteristics of the processes. Screening criteria for the practical application of in situ combustion techniques are presented.

  4. Materials Control in the Fabrication of Enriched Uranium Fuels; Controle des Matieres au Cours de la Fabrication des Combustibles a Base d'Uranium Enrichi; Uchet materialov pri izgotovlenii topliva na obogashchennom urane; Control de Materiales en la Elaboracion de Combustibles de Uranio Enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    Cardwell, Jr., R. G. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    1966-02-15

    measurement were successfully used where alloy fuel content was critical. Scrap handling had an important effect on the materials balance, by which fuel content was confirmed and good accountability was assured. Records and handling procedures, including batching and physical marking methods, were formulated in a manner that assisted the fabricator in criticality control. (author) [French] Grace aux efforts intenses qui ont ete accomplis au cours des 15 dernieres annees dans le domaine de la technologie des elements de combustible par le Laboratoire national d'Oak Ridge, il a ete possible d'etablir des methodes rationnelles de fabrication et de controle des combustibles eraichis, qui trouvent une iaige application dans la fabrication industrielle des elements de combustible a l'heure actuelle. Des techniques eprouvees de manipulation du combustible enrichi en alliages, en dispersion et sous forme d'oxyde en vrac ont ete mises au point et appliquees a l'etude et a la' fabrication des prototypes d'elements combustibles utilises pour le demarrage du reacteur d'essai de materiaux, du reacteur a protection constituee par la masse du ra- lentisseur ou reacteur piscine, du reacteur de puissance transportable construit pat V, du reacteur protection en tour, du reacteur expose a la Conference de Geneve, du reacteur a haut flux pour la production de radioisotopes et du reacteur experimental refroidi par un gaz. L'experience acquise est la base du present memoire qui traite essentiellement des problemes de controle des matieres qui se posent au cours de la fabrication de differents types d'elements de combustible a base d'uranium enrichi et montre comment ils ont ete resolus. Les objectifs principaux d'un systeme rationnel de controle des matieres sont les suivants: 1. reduire le plus possible le nombre des postes matiere a controler; 2. etablir des releves distincts pour chacune des phases principales des operations et les coordonner de maniere a pouvoir relever les ecarts avec un

  5. Aerodynamic and thermal studies of cans of gas cooled fuel elements; Etudes aerodynamiques et thermiques de gaines d'elements combustibles refroidis par gaz

    Energy Technology Data Exchange (ETDEWEB)

    Gelin, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Milliat, J P [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    l'amelioration des grappes et s'est ensuite poursuivie dans les deux Laboratoires pour le refroidissement interne des elements combustibles annulaires. Au fur et a mesure de l'avancement de ces etudes, les moyens d'essais se sont amplifies tandis que les methodes experimentales n'ont cesse de s'ameliorer. Actuellement, les deux Laboratoires, qui travaillent en pleine collaboration, disposent de moyens puissants. Pour les grappes, l'effort a surtout porte sur les pertes de charge dues aux pieces d'assemblage et sur les variations de temperature autour des elements de la grappe. On est arrive ainsi a determiner d'une facon satisfaisante les points chauds de gaine, les deformations des crayons et les conditions de stabilite de ces deformations. Pour les gaines a chevrons, les etudes ont porte, d'une part sur l'evolution des performances en fonction des parametres geometriques, et, d'autre part sur les singularites aerodynamiques et thermiques creees tant par les ailettes que par les interruptions de cartouche. Ces etudes ont abouti a une connaissance tres complete des cartouches choisies pour les reacteurs EDF2 et EDF3, et ouvrent maintenant des perspectives tres encourageantes pour les reacteurs a venir, en particulier les reacteurs equipes d'elements annulaires; parmi les solutions convenant a la gaine interne de l'element annulaire, les corrugations et les ailettes longitudinales ont fait l'objet d'essais assez etendus dans une large plage de nombre de Reynolds. (auteurs)

  6. Use of tri-laurylamine during the retreatment of irradiated fuels; Utilisation de la trilaurylamine au retraitement des combustibles irradies

    Energy Technology Data Exchange (ETDEWEB)

    Bathellier, A; Koehly, G; Perez, J J; Chesne, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The purification of aqueous solutions of plutonium can be made by extraction of the Pu (IV) nitrate complex using trilaurylamine in dodecane. The principal physical properties of this solution are considered along with its extractive properties and the influence of foreign ions on the extraction. The application of this method of extraction in a processing cycle for irradiated material is proposed: either for a final purification process or for auxiliary cycles for recovering plutonium from metal production wastes, oxalate precipitation supernatants, or any general aqueous plutonium waste solution. Also proposed are clean-up procedures for regeneration of an extractive solution which has undergone chemical or radiolytic degradation. (authors) [French] La purification du plutonium contenu dans des solutions aqueuses peut etre effectuee par extraction du nitrate de l'ion tetravalent par la trilaurylamine diluee dans du dodecane. Les principales proprietes physiques de ce solvant sont passees en revue ainsi que ses proprietes extractives et l'influence des ions etrangers sur celles-ci. L'application de cette methode d'extraction dans le cycle de traitement des combustibles irradies est envisagee: soit dans le traitement de purification finale, soit dans les cycles annexes ayant trait a la recuperation de plutonium a partir des scories d'elaboration du metal, des eaux-meres oxaliques et d'une facon generale des solutions aqueuses contenant du plutonium. Des traitements de regeneration du solvant ayant subi des degradations chimique ou radiolytique, sont proposes. (auteurs)

  7. Use of tri-laurylamine during the retreatment of irradiated fuels; Utilisation de la trilaurylamine au retraitement des combustibles irradies

    Energy Technology Data Exchange (ETDEWEB)

    Bathellier, A.; Koehly, G.; Perez, J.J.; Chesne, A. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The purification of aqueous solutions of plutonium can be made by extraction of the Pu (IV) nitrate complex using trilaurylamine in dodecane. The principal physical properties of this solution are considered along with its extractive properties and the influence of foreign ions on the extraction. The application of this method of extraction in a processing cycle for irradiated material is proposed: either for a final purification process or for auxiliary cycles for recovering plutonium from metal production wastes, oxalate precipitation supernatants, or any general aqueous plutonium waste solution. Also proposed are clean-up procedures for regeneration of an extractive solution which has undergone chemical or radiolytic degradation. (authors) [French] La purification du plutonium contenu dans des solutions aqueuses peut etre effectuee par extraction du nitrate de l'ion tetravalent par la trilaurylamine diluee dans du dodecane. Les principales proprietes physiques de ce solvant sont passees en revue ainsi que ses proprietes extractives et l'influence des ions etrangers sur celles-ci. L'application de cette methode d'extraction dans le cycle de traitement des combustibles irradies est envisagee: soit dans le traitement de purification finale, soit dans les cycles annexes ayant trait a la recuperation de plutonium a partir des scories d'elaboration du metal, des eaux-meres oxaliques et d'une facon generale des solutions aqueuses contenant du plutonium. Des traitements de regeneration du solvant ayant subi des degradations chimique ou radiolytique, sont proposes. (auteurs)

  8. Low content uranium alloys for nuclear fuels; Alliages d'uranium a faible teneur pour elements combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, H.; Laniesse, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    A description is given of the structure and the properties of low content alloys containing from 0.1 to 0.5 per cent by weight of Al, Fe, Cr, Si, Mo or a combination of these elements. A study of the kinetics and of the mode of transformation has made it possible to choose the most satisfactory thermal treatment. An attempt has been made to prepare alloys suitable for an economical industrial development having a small {alpha} grain structure without marked preferential orientation, with very fine and stable precipitates as well as a high creep-resistance. The physical properties and the mechanical strength of these alloys are given for temperatures of 20 to 600 deg C. These alloys proved very satisfactory when irradiated in the form of normal size fuel elements. (authors) [French] Sont decrits la structure et les proprietes d'alliages a faible teneur, contenant de 0,1 a 0,5 pour cent en poids de Al, Fe, Cr, Si, Mo ou une combinaison de ces elements. L'etude des cinetiques et du mode de transformation permet de choisir le traitement thermique le plus favorable. On a cherche a mettre, au point des alliages se pretant a une mise en oeuvre industrielle economique et presentant une structure a petits grains {alpha}, sans orientation preferentielle marquee, avec des precipites tres fins et stables ainsi qu'une bonne resistance au fluage. Les proprietes physiques et la resistance mecanique de ces alliages sont decrites entre la temperature ambiante et 600 deg C. Irradies sous forme d'elements combustibles de dimensions normales, ces alliages ont montre un bon comportement. (auteurs)

  9. Low content uranium alloys for nuclear fuels; Alliages d'uranium a faible teneur pour elements combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, H; Laniesse, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    A description is given of the structure and the properties of low content alloys containing from 0.1 to 0.5 per cent by weight of Al, Fe, Cr, Si, Mo or a combination of these elements. A study of the kinetics and of the mode of transformation has made it possible to choose the most satisfactory thermal treatment. An attempt has been made to prepare alloys suitable for an economical industrial development having a small {alpha} grain structure without marked preferential orientation, with very fine and stable precipitates as well as a high creep-resistance. The physical properties and the mechanical strength of these alloys are given for temperatures of 20 to 600 deg C. These alloys proved very satisfactory when irradiated in the form of normal size fuel elements. (authors) [French] Sont decrits la structure et les proprietes d'alliages a faible teneur, contenant de 0,1 a 0,5 pour cent en poids de Al, Fe, Cr, Si, Mo ou une combinaison de ces elements. L'etude des cinetiques et du mode de transformation permet de choisir le traitement thermique le plus favorable. On a cherche a mettre, au point des alliages se pretant a une mise en oeuvre industrielle economique et presentant une structure a petits grains {alpha}, sans orientation preferentielle marquee, avec des precipites tres fins et stables ainsi qu'une bonne resistance au fluage. Les proprietes physiques et la resistance mecanique de ces alliages sont decrites entre la temperature ambiante et 600 deg C. Irradies sous forme d'elements combustibles de dimensions normales, ces alliages ont montre un bon comportement. (auteurs)

  10. Study of the aqueous chemical treatment of uranium zirconium fuels; Etude du traitement chimique des combustibles uraniumzirconium par voie seche

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, M; Nollet, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    A dry process has been studied for separating the uranium from the zirconium-either for recovering the enriched uranium from fuel element production waste, or with a view to treating this waste after irradiation. In this process the alloy is treated with hydrochloric acid at 400 deg. C in a fluidized corundum bed which causes the zirconium to volatilize as tetrachloride and the uranium to form the trichloride. This latter is then converted to the hexafluoride by attack with fluorure. After the laboratory tests, a first pilot plant with a capacity of 1 kg of alloy was tried out at the Fontenay-aux-Roses Nuclear Research Centre; this made it possible to fix the operational conditions for the process. An industrial scale plant was then built with the collaboration of the from Kuhlmann, and operated until a satisfactory process had been developed for treating the waste. This installation treats 3 kg/h of alloy with a yield for the hydrochloric acid of about 50 per cent and with a uranium loss in the zirconium tetrachloride of about 0.1 per cent. An active pilot plant capable of treating of treating a few kilos of irradiated alloy is now being studied. (authors) [French] On a etudie un procede de voie seche pour effectuer la separation de l'uranium et du zirconium - soit en vue de la recuperation de l'uranium enrichi contenu dans les dechets de fabrication des elements combustibles - soit en vue du traitement de ceux-ci apres irradiation. Ce procede consiste a attaquer l'alliage par l'acide chlorhydrique a 400 deg. C dans un lit fluidise de corindon, ce qui a pour effet de volatiliser le zirconium sous forme de tetrachlorure et de transformer l'uranium en trichlorure. Ce dernier est ensuite converti en hexafluorure par action du fluor. Apres des essais de laboratoire, un premier pilote a l'echelle de 1 kg d'alliage a ete experimente au Centre d'Etudes Nucleaires de Fontenay-aux-Roses et a permis de determiner les conditions operatoires du procede. En collaboration avec

  11. Major and trace elements in coal bottom ash at different oxy coal combustion conditions

    CSIR Research Space (South Africa)

    Oboirien, BO

    2014-09-01

    Full Text Available This paper presents a detailed study on the effect of temperature on the concentration of 27 major and trace elements in bottom ash generated from oxy fuel-combustion. The major elements are Na, Mg, Al, K, Ca and Fe and the minor and trace elements...

  12. Enrichment of trace elements in bottom ash from coal oxy-combustion: Effect of coal types

    CSIR Research Space (South Africa)

    Oboirien, BO

    2016-09-01

    Full Text Available In this study, the enrichment of trace elements in two coals under air and oxy-combustion conditions was studied. Twenty-one trace elements were evaluated. The two coal samples had a different concentration for the 21 trace elements, which was due...

  13. Energetic study of combustion instabilities and genetic optimisation of chemical kinetics; Etude energetique des instabilites thermo-acoustiques et optimisation genetique des cinetiques reduites

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Ch.E.

    2005-12-15

    Gas turbine burners are now widely operated in lean premixed combustion mode. This technology has been introduced in order to limit pollutants emissions (especially the NO{sub x}), and thus comply with environment norms. Nevertheless, the use of lean premixed combustion decreases the stability margin of the flames. The flames are then more prone to be disturbed by flow disturbances. Combustion instabilities are then a major problem of concern for modern gas turbine conception. Some active control systems have been used to ensure stability of gas turbines retro-fitted to lean premixed combustion. The current generation of gas turbines aims to get rid of these control devices getting stability by a proper design. To do so, precise and adapted numerical tools are needed even it is impossible at the moment to guarantee the absolute stability of a combustion chamber at the design stage. Simulation tools for unsteady combustion are now able to compute the whole combustion chamber. Its intrinsic precision, allows the Large Eddy Simulation (LES) to take into account numerous phenomena involved in combustion instabilities. Chemical modelling is an important element for the precision of reactive LES. This study includes the description of an optimisation tools for the reduced chemical kinetics. The capacity of the LES to capture combustion instabilities in gas turbine chamber is also demonstrated. The acoustic energy analysis points out that the boundary impedances of the combustion systems are of prime importance for their stability. (author)

  14. Combustion

    CERN Document Server

    Glassman, Irvin

    1987-01-01

    Combustion, Second Edition focuses on the underlying principles of combustion and covers topics ranging from chemical thermodynamics and flame temperatures to chemical kinetics, detonation, ignition, and oxidation characteristics of fuels. Diffusion flames, flame phenomena in premixed combustible gases, and combustion of nonvolatile fuels are also discussed. This book consists of nine chapters and begins by introducing the reader to heats of reaction and formation, free energy and the equilibrium constants, and flame temperature calculations. The next chapter explores the rates of reactio

  15. Use of INAA for investigation of emission of elements in combustion of Polish lignite

    International Nuclear Information System (INIS)

    Janczyszyn, J.; Loska, L.; Pohorecki, W.; Wagner, M.

    2002-01-01

    Instrumental neutron activation analysis (INAA) has been applied for the determination of trace elements content in samples of Polish lignite and its ash. Pairs of results, for lignite and ash, and respective ash contents were used for calculation of the percentage of element remaining in ash after the lignite combustion. (author)

  16. Modeling of the dynamical combustion of explosives: influence of mechanical properties; Modelisation de la combustion dynamique des explodifs: influence des proprietes mecaniques

    Energy Technology Data Exchange (ETDEWEB)

    Picart, D.; Pertuis, C. [CEA Le Ripault, 37 - Tours (France)

    1996-12-31

    Experimental observations performed during the combustion of solid explosives under pressure have shown an unexpected desensitization of the samples when damaged. A simplified method of combustion simulation inside a pressure cell is proposed in this study. The model used is based on the description of the mechanical behaviour of the solid phase. It allows to retrieve the overall experimental results, and in particular the occurrence of anomalous combustion modes. (J.S.) 8 refs.

  17. Combustion

    CERN Document Server

    Glassman, Irvin

    2008-01-01

    Combustion Engineering, a topic generally taught at the upper undergraduate and graduate level in most mechanical engineering programs, and many chemical engineering programs, is the study of rapid energy and mass transfer usually through the common physical phenomena of flame oxidation. It covers the physics and chemistry of this process and the engineering applications-from the generation of power such as the internal combustion automobile engine to the gas turbine engine. Renewed concerns about energy efficiency and fuel costs, along with continued concerns over toxic and particulate emissions have kept the interest in this vital area of engineering high and brought about new developments in both fundamental knowledge of flame and combustion physics as well as new technologies for flame and fuel control. *New chapter on new combustion concepts and technologies, including discussion on nanotechnology as related to combustion, as well as microgravity combustion, microcombustion, and catalytic combustion-all ...

  18. Die Zukunft des Sozialstaates Deutschland: Elemente einer Reformstrategie

    OpenAIRE

    Lampert, Heinz

    1998-01-01

    Die Notwendigkeit einer Reform des Sozialstaates Deutschland ist nach Auffassung des Autors evident, weil eine zu hohe Staats- und Sozialabgabenquote zu Steuervermeidung, Verringerung der Leistungsbereitschaft, Schwarzarbeit, Steuerhinterziehung, Korruption und Betrug führen und die Wettbewerbsfähigkeit der Wirtschaft gefährden. Der Sozialstaat, den der Verfasser als eine der großen Errungenschaften der Neuzeit interpretiert, kann nach seiner Überzeugung aber so reformiert werden, daß soziale...

  19. Formation of the gaseous phase of impurity elements from coal combustion at a thermal power plant

    International Nuclear Information System (INIS)

    Kizil'shtein, L.Ya.; Levchenko, S.V.; Peretyakt'ko, A.G.

    1991-01-01

    Data are reported on the distribution of impurity elements in their principal carriers: organic matter, iron sulfides, and clays. Tests with high-temperature combustion of coals and argillites indicate that elements associated with clay minerals largely remain in ash and slag. They do not pass to the gas phase - a factor to be considered in assessment of environmental impact from thermal power plants and specification of toxic concentration levels of impurity elements in coal

  20. Combustion

    CERN Document Server

    Glassman, Irvin

    1997-01-01

    This Third Edition of Glassman's classic text clearly defines the role of chemistry, physics, and fluid mechanics as applied to the complex topic of combustion. Glassman's insightful introductory text emphasizes underlying physical and chemical principles, and encompasses engine technology, fire safety, materials synthesis, detonation phenomena, hydrocarbon fuel oxidation mechanisms, and environmental considerations. Combustion has been rewritten to integrate the text, figures, and appendixes, detailing available combustion codes, making it not only an excellent introductory text but also an important reference source for professionals in the field. Key Features * Explains complex combustion phenomena with physical insight rather than extensive mathematics * Clarifies postulates in the text using extensive computational results in figures * Lists modern combustion programs indicating usage and availability * Relates combustion concepts to practical applications.

  1. The reprocessing of irradiated fuels improvement and extension of the solvent extraction process; Le traitement des combustibles irradies amelioration et extension du procede utilisant les solvants

    Energy Technology Data Exchange (ETDEWEB)

    Faugeras, P; Chesne, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    . Le traitement au solvant est egalement utilise pour les combustibles de la pile convertisseuse du plutonium (Rapsodie). On expose et commente le schema du traitement, les premiers resultats experimentaux et le projet d'une installation pilote de 1 kg/jour. L'utilisation de la tn-laurylamine dans le cycle de purification du plutonium est envisagee dans l'usine de traitement de La Hague. On presente le schema adopte et les performances du procede. On envisage la vitrification comme traitement definitif des dechets radioactifs concentres des Centres de Marcoule (uranium-irradie) et La Hague (uranium-molybdene irradie). Trois procedes possibles sont decrits et commentes, ainsi que les resultats d'exploitation des installations correspondantes sur elements traceurs. (auteurs)

  2. Results of the irradiation of mixed UO{sub 2} - PuO{sub 2} oxide fuel elements; Resultats d'irradiation d'elements combustibles en oxyde mixte UO{sub 2} - PuO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mikailoff, H.; Mustelier, J.P.; Bloch, J.; Ezran, L.; Hayet, L. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1966-07-01

    In order to study the behaviour of fuel elements used for the first charge of the reactor Rapsodie, a first batch of eleven needles was irradiated in the reactor EL3 and then examined. These needles (having a shape very similar lo that of the actual needles to be used) were made up of a stack of sintered mixed-oxide pellets: UO{sub 2} containing about 10 per cent of PuO{sub 2}. The density was 85 to 97 per cent of the theoretical, value. The diametral gap between the oxide and the stainless steel can was between 0,06 and 0,27 mm. The specific powers varied from 1230 to 2700 W/cm{sup 3} and the can temperature was between 450 and 630 C. The maximum burn-up attained was 22000 MW days/tonne. Examination of the needles (metrology, radiography and {gamma}-spectrography) revealed certain macroscopic changes, and the evolution of the fuel was shown by micrographic studies. These observations were used, together with flux measurements results, to calculate the temperature distribution inside the fuel. The volume of the fission gas produced was measured in some of the samples; the results are interpreted taking into account the temperature distribution in the oxide and the burn-up attained. Finally a study was made both of the behaviour of a fuel element whose central part was molten during irradiation, and of the effect of sodium which had penetrated into some of the samples following can rupture. (author) [French] Afin d'etudier le comportement des elements combustibles destines a la premiere charge du reacteur Rapsodie, une premiere serie de onze aiguilles a ete irradiee dans le reacteur EL3 et examinee apres irradiation. Ces aiguilles (aux caracteristiques geometriques tres proches de celles des aiguilles definitives) etaient constituees d'un empilement de pastilles frittees en oxyde mixte UO{sub 2} a 10 pour cent environ de PuO{sub 2}, dont la densite etait comprise entre 85 et 97 pour cent de la densite theorique. Le jeu diametral entre l'oxyde et la

  3. Results of the irradiation of mixed UO{sub 2} - PuO{sub 2} oxide fuel elements; Resultats d'irradiation d'elements combustibles en oxyde mixte UO{sub 2} - PuO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mikailoff, H; Mustelier, J P; Bloch, J; Ezran, L; Hayet, L [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1966-07-01

    In order to study the behaviour of fuel elements used for the first charge of the reactor Rapsodie, a first batch of eleven needles was irradiated in the reactor EL3 and then examined. These needles (having a shape very similar lo that of the actual needles to be used) were made up of a stack of sintered mixed-oxide pellets: UO{sub 2} containing about 10 per cent of PuO{sub 2}. The density was 85 to 97 per cent of the theoretical, value. The diametral gap between the oxide and the stainless steel can was between 0,06 and 0,27 mm. The specific powers varied from 1230 to 2700 W/cm{sup 3} and the can temperature was between 450 and 630 C. The maximum burn-up attained was 22000 MW days/tonne. Examination of the needles (metrology, radiography and {gamma}-spectrography) revealed certain macroscopic changes, and the evolution of the fuel was shown by micrographic studies. These observations were used, together with flux measurements results, to calculate the temperature distribution inside the fuel. The volume of the fission gas produced was measured in some of the samples; the results are interpreted taking into account the temperature distribution in the oxide and the burn-up attained. Finally a study was made both of the behaviour of a fuel element whose central part was molten during irradiation, and of the effect of sodium which had penetrated into some of the samples following can rupture. (author) [French] Afin d'etudier le comportement des elements combustibles destines a la premiere charge du reacteur Rapsodie, une premiere serie de onze aiguilles a ete irradiee dans le reacteur EL3 et examinee apres irradiation. Ces aiguilles (aux caracteristiques geometriques tres proches de celles des aiguilles definitives) etaient constituees d'un empilement de pastilles frittees en oxyde mixte UO{sub 2} a 10 pour cent environ de PuO{sub 2}, dont la densite etait comprise entre 85 et 97 pour cent de la densite theorique. Le jeu diametral entre l'oxyde et la gaine en acier

  4. Ignition et oxydation des particules de combustible solide pulvérisé Ignition and Oxidation of Pulverized Solid Fuel

    Directory of Open Access Journals (Sweden)

    De Soete G. G.

    2006-11-01

    Full Text Available On présente dans cet article, en utilisant la méthode du ruban chauffé, une étude de la compétition entre (1 la dévolatilisation et l'oxydation consécutive des produits de pyrolyse et (2 l'ignition de la matrice solide et sa combustion rapide. La comparaison entre le moment de l'ignition et le début de la pyrolyse permet de déterminer en fonction de la température, de la taille des particules et de la concentration en oxygène, le domaine dans lequel l'ignition d'un combustible solide pyrolysable est du type whole coal ignition (c'est-à-dire lorsque l'ignition intervient avant que la pyrolyse devienne mesurable. Les résultats suggèrent que ce type d'ignition doit s'effectuer en règle générale dans les conditions de mise en oeuvre des combustibles solides pulvérisés dans les flammes industrielles. Dans le cas de l'ignition whole coal , la vitesse de combustion de la matrice solide est inhibée dans la période qui suit l'ignition. Cette inhibition est due d'une part à la difficulté pour l'oxygène de diffuser dans les pores pendant la sortie des produits de pyrolyse, et d'autre part à la consommation préférentielle de l'oxygène dans l'oxydation des produits de pyrolyse, principalement dans le cas où cette oxydation se développe sous forme de flamme. Ce n'est que lorsque la pyrolyse s'achève que la vitesse de combustion hétérogène peut atteindre sa valeur stationnaire normale, qui est alors pratiquement identique à celle du coke. Aux températures situées entre la température d'ignition du combustible solide et la température d'extinction du coke résiduel, la combustion est incomplète, une extinction intervenant à un degré de dévolatilisation d'autant plus grande que la température est élevée. Ce phénomène s'explique qualitativement par la théorie classique d'ignition thermique lorsqu'on l'applique au cas particulier des combustibles solides pyrolysables. Les températures d'ignition ainsi que les d

  5. Optical Engines as Representative Tools in the Development of New Combustion Engine Concepts Moteurs transparents comme outils représentatifs dans le développement de nouveaux concepts des moteurs à combustion interne

    Directory of Open Access Journals (Sweden)

    Kashdan J.

    2011-11-01

    (EGR. A comparison has been made between simulated EGR (using pure nitrogen with real EGR under Diesel LTC conditions. Finally, “pure”, single component fuels are often employed in optical Diesel engines due to laser diagnostic constraints. However, these fuels generally differ from standard Diesel fuel in terms of cetane number and fuel volatility which can significantly influence the combustion and emissions characteristics in optical engines. These aspects have also been investigated within the present study. An improved understanding of the differences between optical and all-metal engines has allowed us to develop appropriate strategies to compensate for these differences on the optical engine. It is shown here that combustion phasing (and engine-out emissions matching between optical and all-metal engines can be achieved even for advanced LTC Diesel combustion strategies. The ability to ensure fully representative combustion and emissions behaviour of optical engines ultimately increases the value of optical engine data, highlighting the importance of using such engines as research tools for the further development of innovative, low emission combustion concepts. Les moteurs monocylindres transparents sont employés comme outils de recherche et de développement des moteurs à combustion interne. Ils permettent l’utilisation de techniques de diagnostics non-intrusifs (qualitatifs et quantitatifs pour étudier des phénomènes comme l’aérodynamique interne, la préparation du mélange, la combustion et la formation de polluants. Ces données expérimentales sont importantes pour la validation des modèles numériques et permettent également d’obtenir une compréhension détaillée des phénomènes physiques se déroulant dans la chambre. Les données recueillies aident au développement des nouvelles stratégies de combustion telles que la combustion homogène (HCCI et la combustion Diesel à basse température (LTC. Dans ce contexte, il est important

  6. Variability of total and mobile element contents in ash derived from biomass combustion

    Czech Academy of Sciences Publication Activity Database

    Száková, J.; Ochecová, P.; Hanzlíček, Tomáš; Perná, Ivana; Tlustoš, P.

    2013-01-01

    Roč. 67, č. 11 (2013), s. 1376-1385 ISSN 0366-6352 R&D Projects: GA MZe QI102A207 Institutional support: RVO:67985891 Keywords : biomass combustion * fly ash * bottom ash * element contents Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.193, year: 2013

  7. Determination of elements in citrus leaves; Dosage des elements dans les feuilles de citrus

    Energy Technology Data Exchange (ETDEWEB)

    Masozera, C.; Compernolle, G. van; Brandstetr, J.; Krivanek, M. [Centre nucléaire TRICO, Kinshasa (Congo, The Democratic Republic of the); Université Lovanium, Kinshasa (Congo, The Democratic Republic of the)

    1970-01-15

    In many agricultural stations and farms most of the problems encountered generally reduce to questions of diminished yield. This may be due to a number of factors, including soil exhaustion and the application of fertilizers of unsuitable formula. The chemical impoverishment of the soil is due to the leaching-out phenomenon, i- e. the washing out of bases, and to the ''exportation'' of fertilizer elements in the form of crops in years when nothing has been returned to the soil. These losses have a particularly adverse effect if the parent rock does not contain sufficient mineral reserves to compensate for them by a slow alteration process. Such impoverishment is revealed by soil and foliar analyses. The authors have attempted to determine the content in citrus plants of the following elements: Mn, P, Cu, Cl and K (the latter on three samples only). After collection, the samples are treated by Bransolten's method (Rapport de Recherche TRICO № 15/1968), dried for at least 12 hours at 105°C, followed by pulverization of the leaves, after which the determination is carried out. The determination of Mn and Cl is very simple, as is that of Cu. The latter is determined by activation with slow neutrons in order to avoid Zn formation. The phosphorus content is determined by measuring the beta-radiation emitted by the radioactive elements. In this case particular precautions must be taken to ensure that the same layer is used for the samples and the standards, since beta-radiation is absorbed by these layers. For the K and Na determinations thermal neutrons are used for activation and a Ge(Li) detector for measurement of the gamma-spectra. Because of the high resolution of the detector, the two elements can be determined without separation. (author) [French] La plupart des problèmes que l’on rencontre dans plusieurs stations ou exploitations agricoles se résument généralement à une diminution de rendement. Cette dernière peut être provoquée par plusieurs

  8. Dispersions of Oxides in Oxide Matrices as High-Temperature Reactor Fuels; Dispersions d'oxyde dans des matrices d'oxyde, utilisees comme combustibles dans des reacteurs a haute temperature; Dispersiya okisej v okislovykh matritsakh v kachestve topliva dlya vysokotemperaturnogo reaktora; Empleo de dispersiones de oxidos en matrices de oxidos, como combustibles para reactores de elevada temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J. [Atomic Energy Research Establishment, Harwell (United Kingdom)

    1963-11-15

    et l'aptitude a retenir les produits de fission sont les deux caracteristiques les plus importantes de l'integrite du combustible. La compatibilite des elements constitutifs des combustibles les uns avec les autres et avec le refroidisseur exerce une influence sur la stabilite dimensionnelle, mais les combustibles sous forme d'oxydes presentent beaucoup d'avantages a cet egard. Les variations de dimension sous irradiation ont trois composantes: les dommages causes a la matrice par les neutrons et les produits de fission, les dommages causes par les rayonnements a la phase produit fissile/produit fertile, les effets d'une accumulation de produits de fission gazeux. Les contraintes thermiques peuvent egalement etre a l'origine de modifications de forme. Cependant, les renseignements dont on dispose sur les mecanismes de la relaxation des contraintes sont trop limites pour qu'il soit possible de formuler des appreciations theoriques sur le comportement du materiau. Les etudes sur le degagement des produits de fission provenant d'un melange d'oxydes fissiles et fertiles sous faible irradiation ou pour un taux de combustion eleve, ont porte principalement sur les produits gazeux, notamment le xenon. Les donnees sur le degagement d'autres produits de fission sont tres limitees comme le sont d'ailleurs celles qui ont trait aux mouvements des produits de fission en general a travers les materiaux que l'on peut utiliser pour les matrices. Des etudes relatives a l'etancheite des oxydes purs frittes indiquent qu'il faut atteindre des densites egales a 95% au moins et peut-etre meme a 98% de la densite theorique pour supprimer la porosite ouverte dans de telles matrices. On peut recourir a diverses methodes pour preparer des particules de produits fissiles et fertiles, pour les revetir et pour les incorporer dans des matrices de densite elevee. Les travaux sur les procedes de transformation a l'echelle du laboratoire sont assez avances. (author) [Spanish] El autor examina la

  9. Hydraulic modelling of the CARA Fuel element; Desarrollo hidraulico del combustible CARA

    Energy Technology Data Exchange (ETDEWEB)

    Brasnarof, Daniel O; Juanico, Luis [Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Disenios Avanzados y Evaluacion Economica; Giorgi, M [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Materiales; Ghiselli, Alberto M; Zampach, Ruben; Fiori, Jose M; Yedros, Pablo A [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Ensayos no Destructivos

    2004-07-01

    The CARA fuel element is been developing by the National Atomic Energy Commission for both Argentinean PHWRs. In order to keep the hydraulic restriction in their fuel channels, one of CARA's goals is to keep its similarity with both present fuel elements. In this paper is presented pressure drop test performed at a low-pressure facility (Reynolds numbers between 5x10{sup 4} and 1,5x10{sup 5}) and rational base models for their spacer grid and rod assembly. Using these models, we could estimate the CARA hydraulic performance in reactor conditions that have shown to be satisfactory. (author) [Spanish] Con el objeto de validar la similitud hidraulica del elemento combustible CARA con los actuales combustibles de Atucha y Embalse, se realizaron ensayos de perdida de carga en el circuito CBP del CAC con un nuevo diseno de separador de mejor desempeno hidraulico. Se presenta aqui el analisis de los mismos, de los cuales se validaron modelos de base racional para estimar las restricciones hidraulicas de los distintos componentes estructurales (separadores, grillas y barras combustibles) en funcion del flujo refrigerante. Se estimo asi la caida de presion del CARA dentro del canal combustible Embalse en condiciones nominales de reactor, siendo la misma similar al del combustible actual de 37 barras. (autor)

  10. Environmental Impact of Munition and Propellant Disposal (Impact Environnemental de l’Elimination des Munitions et des Combustibles)

    Science.gov (United States)

    2010-02-01

    the Future of Demil 3-29 3.4.2 Poster Session 3-32 3.4.2.1 The Situation in Lithuania: The Studies on the Explosive Contamination, 3-32 Their Toxic...Presentations and Documents Supporting Capability Assessments A-1 Annex B – Presentations, Paper/ Posters and Videos from the Sofia Meeting B-1 Annex C...sur l’environnement. La réunion a inclus des participants provenant de l’OTAN et des partenaires dont la Russie et la Géorgie. Les sessions étaient

  11. Gamma spectrometry at OSIRIS. Determination of the power and combustion rate of irradiated fuel elements

    International Nuclear Information System (INIS)

    Destot, M.; Musso, J.F.; Cerles, J.M.

    1975-12-01

    An original gamma spectrometer is available at Saclay near the core of the Osiris reactor. With such a device, it is possible to investigate nuclear fuel elements irradiated at Osiris or originating from power reactors. It is quite possible to build devices based on this principle in nuclear power reactors, more particularly in water reactors. With such a device, it is possible to follow the evolution in space and with time of a large number of fission products, and from there to draw precious conclusions relative to reactor safety (e.g. failed element detection) and to fuel economy (i.e. determination of combustion rate). The general characteristics of the device are given as well as its applications: determination of the mass combustion and of the linear power of an irradiated element. A non-destructive, versatile and fast means of investigation is therefore given by the installation of gamma spectroscopy inside a reactor [fr

  12. Cfd Based Shape Optimization of Ic Engine Optimisation de l'admission et des chambres de combustion des moteurs avec la modélisation 3D

    Directory of Open Access Journals (Sweden)

    Griaznov V.

    2006-12-01

    Full Text Available Intense competition and global regulations in the automotive industry has placed unprecedented demands on the performance, efficiency, and emissions of today's IC engines. The success or failure of a new engine design to meet these often-conflicting requirements is primarily dictated by its capability to provide minimal restriction for the inducted and exhausted flow and by its capability to generate strong large-scale in-cylinder motion. The first criterion is directly linked to power performance of the engine, while the latter has been shown to control the burn rate in IC engines. Enhanced burn rates are favorable to engine efficiency and partial load performance. CFD based numerical simulations have recently made it possible to study the development of such engine flows in great details. However, they offer little guidance for modifying the ports and chamber geometry controlling the flow to meet the desired performance. This paper presents a methodology which combines 3D, steady state CFD techniques with robust numerical optimization tools to design, rather than just evaluate the performance, of IC engine ports and chambers. La forte concurrence et les réglementations dans l'industrie automobile entraînent aujourd'hui une exigence sans précédent de performance, de rendement et d'émissions pour les moteurs à combustion interne. Le succès ou l'échec de la conception d'un nouveau moteur satisfaisant à ces propriétés, souvent contradictoires, est dicté, dans un premier temps, par l'obtention d'une restriction minimale des débits d'admission et d'échappement, ensuite, par la nécessité de générer des écoulements forts de grande amplitude. Le premier critère est directement lié à la performance du moteur, tandis que le second est reconnu comme contrôlant la combustion. Des dégagements de chaleur accélérés améliorent le rendement et les performances à faible charge. La simulation 3D rend possible depuis peu d

  13. Ameliorer les performances environnementales des centrales a charbon pulverise via la co-combustion de combustible derive de dechets

    Science.gov (United States)

    Vekemans, Odile Geraldine

    Coal supplies around 28% of the world's energy needs and produces some 40% of the world's electricity. In the United States, close to 650 coal power plants currently produce electricity from coal, the majority of witch are equipped with pulverized coal boilers build in the 80's. Due to coal's intrinsic content in nitrogen and sulfur, its combustion is associated with high levels of NOx and SO2 emissions, that are responsible, among other thing, for acid rains. In order to help reduce SO2 emissions of coal power plant, this thesis focuses on the behaviour of a novel feedstock called ReEF(TM) or ReEngineered Feedstock(TM), developed by the company Accordant Energy LLCRTM, that combines non recyclable waste and alkaline sorbent. Since waste have a high calorific value and do not contain sulfur, and since alkaline sorbents (such as limestone) are able to react with SO2 and capture it in solid state, co-combustion of ReEF(TM) and coal could reduce SO2 emissions inside the furnace chamber itself. This technology easy to implement, as it requires a limited initial investment and limited additional space, could help avoid the construction of costly flue gas treatment unit downstream from the furnace. However, careless combustion of this engineered fuel could have disastrous consequences for the coal power plant owners. This thesis, then, deliver one among the first experimental study of co-combustion of coal and ReEF(TM) in conditions characteristic of pulverized coal boilers. As a first step, in order to get familiarize with the feedstock under study, the thermal degradation of a ReEF(TM) without sorbent and of its components is analyzed by thermogravimetry. With the analysis of more than 70 samples at heating rates ranging from 5°C/min to 400°C/min we are able to conclude that ReEF(TM) thermal degradation can be seen as the independent thermal degradation of its components, as long as heat transfer limitations are taken into account. Thus, no substantial chemical

  14. The life of some metallic uranium based fuel elements; Duree de vie de quelques combustibles a base d'uranium metal

    Energy Technology Data Exchange (ETDEWEB)

    Stohr, J A; Englander, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Description of some theoretical and experimental data concerning the design and most economic preparation of metallic uranium based fuel elements, which are intended to produce an energy of 3 kW days/g of uranium in a thermal reactor, at a sufficiently high mean temperature. Experimental results obtained by testing by analogy or by actually trying out fuel elements obtained by alloying uranium with other metals in proportions such that the resistance to deformation of the alloy produced is much higher than that of pure metallic uranium and that the thermal utilisation factor is only slightly different from that of the uranium. (author) [French] Description de quelques donnees theoriques et experimentales concernant la conception et la preparation la plus economique d'elements combustibles a base d'uranium metallique naturel, destines a degager dans un reacteur thermique une energie de l'ordre de 3 kWj/g d'uranium a une temperature moyenne suffisamment elevee. Resultats experimentaux acquis par tests analogiques ou reels sur combustibles obtenus par alliage de l'uranium avec des elements metalliques en proportions telles que la resistance a la deformation soit bien superieure a celle de l'uranium metal pur et que le facteur propre d'utilisation thermique n ne soit que peu affecte. (auteur)

  15. Dosage of fission products in irradiated fuel treatment effluents (radio-chemical method); Dosage des produits de fission dans les effluents du traitement des combustibles irradies (methode radiochimique)

    Energy Technology Data Exchange (ETDEWEB)

    Auchapt, J [Commissariat a l' Energie Atomique, Marcoule (France). Centre d' Etudes Nucleaires

    1966-07-01

    The dosage methods presented here are applicable to relatively long-lived fission products present in the effluents resulting from irradiated fuel treatment processes (Sr - Cs - Ce - Zr - Nb - Ru - I). The methods are based on the same principle: - addition of a carrying-over agent - chemical separation over several purification stages, - determination of the chemical yield by calorimetry - counting of an aliquot liquid portion. (author) [French] Les methodes de dosage presentees concernent les produits de fission a vie relativement longue presents dans les effluents de traitement des combustibles irradies (Sr - Cs - Ce - Zr - Nb - Ru - I). Elles sont toutes basees sur le meme principe: - addition d'entraineur, - separation chimique en plusieurs stades de purification, - determination du rendement chimique par calorimetrie, - comptage d'une aliquote liquide. (auteur)

  16. Trace element emissions from spontaneous combustion of gob piles in coal mines, Shanxi, China

    Science.gov (United States)

    Zhao, Y.; Zhang, Jiahua; Chou, C.-L.; Li, Y.; Wang, Z.; Ge, Y.; Zheng, C.

    2008-01-01

    The emissions of potentially hazardous trace elements from spontaneous combustion of gob piles from coal mining in Shanxi Province, China, have been studied. More than ninety samples of solid waste from gob piles in Shanxi were collected and the contents of twenty potentially hazardous trace elements (Be, F, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sn, Sb, Hg, Tl, Pb, Th, and U) in these samples were determined. Trace element contents in solid waste samples showed wide ranges. As compared with the upper continental crust, the solid waste samples are significantly enriched in Se (20x) and Tl (12x) and are moderately enriched in F, As, Mo, Sn, Sb, Hg, Th, and U (2-5x). The solid waste samples are depleted in V, Cr, Mn, Co, Ni, Cu, and Zn. The solid waste samples are enriched in F, V, Mn, Cr, Co, Ni, Cu, Zn, Sb, Th, and U as compared with the Shanxi coals. Most trace elements are higher in the clinker than in the unburnt solid waste except F, Sn, and Hg. Trace element abundances are related to the ash content and composition of the samples. The content of F is negatively correlated with the ash content, while Pb is positively correlated with the ash. The concentrations of As, Mn, Zn, and Cd are highly positively correlated with Fe2O3 in the solid waste. The As content increases with increasing sulfur content in the solid waste. The trace element emissions are calculated for mass balance. The emission factors of trace elements during the spontaneous combustion of the gobs are determined and the trace element concentrations in the flue gas from the spontaneous combustion of solid waste are calculated. More than a half of F, Se, Hg and Pb are released to the atmosphere during spontaneous combustion. Some trace element concentrations in flue gas are higher than the national emission standards. Thus, gob piles from coal mining pose a serious environmental problem. ?? 2007 Elsevier B.V. All rights reserved.

  17. Element budgets of forest biomass combustion and ash fertilisation - a Danish case-study

    DEFF Research Database (Denmark)

    Ingerslev, Morten; Skov, Simon; Sevel, Lisbeth

    2011-01-01

    Harvest of forest biomass for energy production may lead to a significant export of nutrients from the forest. Ash spreading and recycling of nutrients from wood chip combustion to the forest has come into focus as a means for counteracting the nutrient export. This study was carried out to examine...... the retention of various elements in the different ash fractions and utilise the nutrient recovery to evaluate the fertiliser quality of the examined ash. The mass and element flux of wood chips, bottom ash, cyclone fly ash and condensation sludge at Ebeltoft central heating plant was studied over a four day...

  18. Transient dynamic finite element analysis of hydrogen distribution test chamber structure for hydrogen combustion loads

    International Nuclear Information System (INIS)

    Singh, R.K.; Redlinger, R.; Breitung, W.

    2005-09-01

    Design and analysis of blast resistant structures is an important area of safety research in nuclear, aerospace, chemical process and vehicle industries. Institute for Nuclear and Energy Technologies (IKET) of Research Centre- Karlsruhe (Forschungszentrum Karlsruhe or FZK) in Germany is pursuing active research on the entire spectrum of safety evaluation for efficient hydrogen management in case of the postulated design basis and beyond the design basis severe accidents for nuclear and non-nuclear applications. This report concentrates on the consequence analysis of hydrogen combustion accidents with emphasis on the structural safety assessment. The transient finite element simulation results obtained for 2gm, 4gm, 8gm and 16gm hydrogen combustion experiments concluded recently on the test-cell structure are described. The frequencies and damping of the test-cell observed during the hammer tests and the combustion experiments are used for the present three dimensional finite element model qualification. For the numerical transient dynamic evaluation of the test-cell structure, the pressure time history data computed with CFD code COM-3D is used for the four combustion experiments. Detail comparisons of the present numerical results for the four combustion experiments with the observed time signals are carried out to evaluate the structural connection behavior. For all the combustion experiments excellent agreement is noted for the computed accelerations and displacements at the standard transducer locations, where the measurements were made during the different combustion tests. In addition inelastic analysis is also presented for the test-cell structure to evaluate the limiting impulsive and quasi-static pressure loads. These results are used to evaluate the response of the test cell structure for the postulated over pressurization of the test-cell due to the blast load generated in case of 64 gm hydrogen ignition for which additional sets of computations were

  19. Toward the modeling of combustion reactions through discrete element method (DEM) simulations

    Science.gov (United States)

    Reis, Martina Costa; Alobaid, Falah; Wang, Yongqi

    2018-03-01

    In this work, the process of combustion of coal particles under turbulent regime in a high-temperature reaction chamber is modeled through 3D discrete element method (DEM) simulations. By assuming the occurrence of interfacial transport phenomena between the gas and solid phases, one investigates the influence of the physicochemical properties of particles on the rates of heterogeneous chemical reactions, as well as the influence of eddies present in the gas phase on the mass transport of reactants toward the coal particles surface. Moreover, by considering a simplistic chemical mechanism for the combustion process, thermochemical and kinetic parameters obtained from the simulations are employed to discuss some phenomenological aspects of the combustion process. In particular, the observed changes in the mass and volume of coal particles during the gasification and combustion steps are discussed by emphasizing the changes in the chemical structure of the coal. In addition to illustrate how DEM simulations can be used in the modeling of consecutive and parallel chemical reactions, this work also shows how heterogeneous and homogeneous chemical reactions become a source of mass and energy for the gas phase.

  20. Experimental Combustion Dynamics Behavior of a Multi-Element Lean Direct Injection (LDI) Gas Turbine Combustor

    Science.gov (United States)

    Acosta, Waldo A.; Chang, Clarence T.

    2016-01-01

    An experimental investigation of the combustion dynamic characteristics of a research multi-element lean direct injection (LDI) combustor under simulated gas turbine conditions was conducted. The objective was to gain a better understanding of the physical phenomena inside a pressurized flametube combustion chamber under acoustically isolated conditions. A nine-point swirl venturi lean direct injection (SV-LDI) geometry was evaluated at inlet pressures up to 2,413 kPa and non-vitiated air temperatures up to 867 K. The equivalence ratio was varied to obtain adiabatic flame temperatures between 1388 K and 1905 K. Dynamic pressure measurements were taken upstream of the SV-LDI, in the combustion zone and downstream of the exit nozzle. The measurements showed that combustion dynamics were fairly small when the fuel was distributed uniformly and mostly due to fluid dynamics effects. Dynamic pressure fluctuations larger than 40 kPa at low frequencies were measured at 653 K inlet temperature and 1117 kPa inlet pressure when fuel was shifted and the pilot fuel injector equivalence ratio was increased to 0.72.

  1. Control Methods Used in the Department of Metallurgy for Structure and Fuel Elements; Methodes de Controle Utilisees au Departement de Metallurgie pour les Elements de Structure et les Elements Combustibles; Metody kontrolya struktury toplivnykh ehlementov v departamente metallurgii; Metodos de Control Utilizados en el Departamento de Metalurgia para los Elementos Estructurales y Combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Destribats, Marie-Therese; Allain, C.; Prot, A.; Thome, P. [Centre d' Etudes Nucleaires de Saclay (France)

    1965-09-15

    nombreuses methodes de controle non destructif pour les differents materiaux entrant dans leur realisation, en particulier: radiographie et gammagraphie, methodes ultrasonores et courants de Foucault. Le memoire decrit les controles effectues au cours de la fabrication des reacteurs des filieres EDF (graphite- gaz) et EL4 (eau lourde) et des elements colamines. Les auteurs insistent sur quelques points caracteristiques de ces diverses methodes, dont certaines sont bien connues. Filiere EDF: mesure des epaisseurs des parois des tubes en uranium ou uranium allie, par ultrasons; recherche des cavites de ces tubes, par gammagraphie; controle des traitements thermiques de ces tubes, par ultrasons; recherche des defauts (inclusions, criques), par ultrasons dans les billettes et ebauches des gaines en MgZr; controle de l'etancheite des cartouches, par ressuage d'helium. Filiere EL 4: mesure des epaisseurs des parois des tubes de force, et de guidage en Zircaloy, par ultrasons et courants de Foucault; examen des tubes de force en Zircaloy et tube de gaine en acier inoxydable par ultrasons; radiographie sous vide des gaines en Be; controle d'etancheite des crayons, par ressuage d'helium. Elements colamines : mesure de l'epaisseur des gaines, par courants de Foucault puises; recherche de la position de l'ame sur tubes et plaques, par radiographie, comptage gamma et courants de Foucault puises; controle de l'homogeneite.du combustible, par comptage gamma; detection des defauts dans les billettes en ZrU, par ultrasons et gammagraphie; recherche des zones decollees des plaques, par ultrasons, courants de Foucault puises et mesure de resistivite. Ces mises au point ont ete faites en vue de leur utilisation industrielle. Plusieurs de ces controles sont effectues couramment en cours de fabrication, d'autres le seront prochainement et certains sont susceptibles de l'etre a plus longue echeance. (author) [Spanish] Los estudios del Commissariat a l'Energie Atomique sobre diversos tipos de

  2. Une installation expérimentale pour l'étude du traitement par combustion des fumées industrielles An Experimental Plant for Processing Industrial Fumes by Combustion

    Directory of Open Access Journals (Sweden)

    Morillon R.

    2006-11-01

    Full Text Available Le rejet à l'atmosphère d'effluents gazeux d'origine industrielle entraîne un accroissement sensible de la pollution atmosphérique ; en outre, il s'accompagne souvent d'une perte d'énergie lorsque l'élément polluant est un hydrocarbure. Dans ce cas, l'utilisation du gaz naturel pour le traitement par combustion des fumées industrielles apporte une solution élégante et souvent peu coûteuse grâce à la récupération d'énergie qu'il est possible de faire. La première partie de l'article rappelle les aspects théoriques de ce traitement ; en particulier, l'influence des divers éléments sur son efficacité y est discutée (composition de l'atmosphère polluée, température, temps de séjour, etc.. II apparaît ainsi que diverses conditions doivent être remplies simultanément pour obtenir une efficacité satisfaisante. Afin de disposer d'éléments d'ingénierie permettant de construire les unités de traitement les plus efficaces et les plus sûres possible, au coût le plus bas possible, la Direction des études et techniques nouvelles du Gaz de France a réalisé une installation expérimentale qui est présentée dans la deuxième partie de l'article. Enfin, quelques examples d'utilisation de cette installation expérimentale, qui constitue un nouvel outil de travail mis à la disposition des utisitateurs et des constructeurs, sont décrits dans la troisième partie de l'article. The discharge into the atmosphere of industrial waste gases causes substantially increased air pollution. Moreover, it is often accompanied by loss of energy when the polluting element is a hydrocarbon. In such cases, the use of natural gas for processing industrial fumes by combustion provides an elegant solution, which moy often prove economical too becouse of the recovery of energy it makes possible. The first part of this article reviews the theoretical aspects of such processing. The way in which its effectiveness is affected by various parameters

  3. Trace elements in co-combustion of solid recovered fuel and coal

    DEFF Research Database (Denmark)

    Wu, Hao; Glarborg, Peter; Jappe Frandsen, Flemming

    2013-01-01

    Trace element partitioning in co-combustion of a bituminous coal and a solid recovered fuel (SRF) was studied in an entrained flow reactor. The experiments were carried out at conditions similar to pulverized coal combustion, with SRF shares of 7.9 wt.% (wet basis), 14.8 wt.% and 25.0 wt.......%. In addition, the effect of additives such as NaCl, PVC, ammonium sulphate, and kaolinite on trace element partitioning was investigated. The trace elements studied were As, Cd, Cr, Pb, Sb and Zn, since these elements were significantly enriched in SRF as compared to coal. During the experiments, bottom ash...... was collected in a chamber, large fly ash particles were collected by a cyclone with a cut-off diameter of ~2.5 μm, and the remaining fly ash particles were gathered in a filter. It was found that when coal was co-fired with SRF, the As, Cd, Pb, Sb and Zn content in filter ash/cyclone ash increased almost...

  4. Combustion characteristics of water-insoluble elemental and organic carbon in size selected ambient aerosol particles

    Directory of Open Access Journals (Sweden)

    K. Wittmaack

    2005-01-01

    Full Text Available Combustion of elemental carbon (EC and organic carbon (OC contained in ambient aerosol matter was explored using scanning electron microscopy (SEM in combination with energy dispersive X-ray analysis (EDX. To ease identification of the particles of interest and to avoid or at least reduce interaction with simultaneously sampled inorganic oxides and salts, the approach used in this work differed in two ways from commonly applied procedures. First, rather than using a mixture of particles of vastly different sizes, as in PM10 or PM2.5, aerosol matter was collected in a 5-stage impactor. Second, the water soluble fraction of the collected matter was removed prior to analysis. Diesel soot particles, which appeared in the well-known form of chain-type aggregates, constituted the major fraction of EC. In contrast, OC containing particles were observed in a variety of shapes, including a sizable amount of bioaerosol matter appearing mostly in the size range above about 1 µm. During heating in ambient air for 1h, diesel soot particles were found to be stable up to 470°C, but complete combustion occurred in a narrow temperature interval between about 480 and 510°C. After diesel soot combustion, minute quantities of 'ash' were observed in the form of aggregated tiny particles with sizes less than 10 nm. These particles could be due to elemental or oxidic contaminants of diesel soot. Combustion of OC was observed over a wide range of temperatures, from well below 200°C to at least 500°C. Incompletely burnt bioaerosol matter was still found after heating to 600°C. The results imply that the EC fraction in aerosol matter can be overestimated significantly if the contribution of OC to a thermogram is not well separated.

  5. Cells for the examination of irradiated plutonium fuel elements - two years operation - may 1961/may 1963 (1963); Cellules pour examen d'elements combustibles au plutonium irradies - deux ans d'exploitation - mai 1961/mai 1963 (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Valentin, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1963-07-01

    Within the framework of the 'Rapsodie' fast reactor program, prototype plutonium fuel elements are irradiated and then examined in an {alpha} {beta} {gamma} laboratory at Saclay. This laboratory consists of five in line cells and a lead enclosure microscope. Each cell contains an {alpha} sealed removable box 4 ft 3 in. high, 4 ft 11 in. wide and 5 ft 1 in. deep, fitted with one or two magnetic transmission indirect manipulators. The boxes are contained in an {beta} {gamma} shielded enclosure whose front face is constructed of cast iron panels 21-2/3 in. thick. Nitrogen circulating in a closed loop forms the atmosphere of the boxes. This laboratory is essentially intended for metallurgical research. The functions of the various cells are as follows: transferring and packing, cutting, density measurement and cathodic etching, storage and metallography. Work on radioactive materials began in April 1961. Operational incidents have always been of a material nature only. (author) [French] Dans le cadre du projet de reacteur rapide Rapsodie, des elements combustibles prototypes au plutonium sont, apres irradiation, examines a Saclay dans un laboratoire {alpha} {beta} {gamma}. Celui-ci comprend cinq cellules en ligne et une enceinte en plomb contenant un microscope telecommande. Chaque cellule est constituee d'un caisson etanche (1, 3 m x 1, 5 m x 1, 56m) equipee d'un ou deux manipulateurs indirects a transmissions magnetiques. Les caissons sont places, dans une enceinte {beta} {gamma} dont la face avant est formee de blocs en fonte ayant 55 cm d'epaisseur. L'atmosphere des caissons est de l'azote, circulant en circuit ferme. Ce laboratoire est destine essentiellement a des recherches metallurgiques. Les fonctions des differentes cellules sont: conditionnement et transferts, tronconnage, mesure de densite et polissage ionique, stockage, metallographie. Le travail sur materiaux radioactifs a commence en avril 1961. Les incidents d'exploitation ont toujours ete d

  6. Cells for the examination of irradiated plutonium fuel elements - two years operation - may 1961/may 1963 (1963); Cellules pour examen d'elements combustibles au plutonium irradies - deux ans d'exploitation - mai 1961/mai 1963 (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Valentin, A. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1963-07-01

    Within the framework of the 'Rapsodie' fast reactor program, prototype plutonium fuel elements are irradiated and then examined in an {alpha} {beta} {gamma} laboratory at Saclay. This laboratory consists of five in line cells and a lead enclosure microscope. Each cell contains an {alpha} sealed removable box 4 ft 3 in. high, 4 ft 11 in. wide and 5 ft 1 in. deep, fitted with one or two magnetic transmission indirect manipulators. The boxes are contained in an {beta} {gamma} shielded enclosure whose front face is constructed of cast iron panels 21-2/3 in. thick. Nitrogen circulating in a closed loop forms the atmosphere of the boxes. This laboratory is essentially intended for metallurgical research. The functions of the various cells are as follows: transferring and packing, cutting, density measurement and cathodic etching, storage and metallography. Work on radioactive materials began in April 1961. Operational incidents have always been of a material nature only. (author) [French] Dans le cadre du projet de reacteur rapide Rapsodie, des elements combustibles prototypes au plutonium sont, apres irradiation, examines a Saclay dans un laboratoire {alpha} {beta} {gamma}. Celui-ci comprend cinq cellules en ligne et une enceinte en plomb contenant un microscope telecommande. Chaque cellule est constituee d'un caisson etanche (1, 3 m x 1, 5 m x 1, 56m) equipee d'un ou deux manipulateurs indirects a transmissions magnetiques. Les caissons sont places, dans une enceinte {beta} {gamma} dont la face avant est formee de blocs en fonte ayant 55 cm d'epaisseur. L'atmosphere des caissons est de l'azote, circulant en circuit ferme. Ce laboratoire est destine essentiellement a des recherches metallurgiques. Les fonctions des differentes cellules sont: conditionnement et transferts, tronconnage, mesure de densite et polissage ionique, stockage, metallographie. Le travail sur materiaux radioactifs a commence en avril 1961. Les incidents d

  7. Prevention of criticality accidents. Fuel elements storage; Prevencion de accidentes de criticidad. Almacenamiento de elementos combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Canavese, S I; Capadona, N M

    1991-12-31

    Before the need to store fuel elements of the plate type MTR (Materials Testing Reactors), produced with enriched uranium at 20% in U235 for research reactors, it requires the design of a deposit for this purpose, which will give intrinsic security at a great extent and no complaints regarding its construction, is required. (Author). [Espanol] Partiendo de la necesidad de almacenar elementos combustibles tipo placa MTR (Materials Testing Reactors), producidos con uranio enriquecido al 20% en U235 para reactores de investigacion, se requiere el diseno de un deposito para tal fin que brinde esencialmente un alto grado de seguridad intrinseca y que no ofrezca complicaciones en cuanto a su construccion. (Autor).

  8. Design and Fabrication of Oxygen/RP-2 Multi-Element Oxidizer-Rich Staged Combustion Thrust Chamber Injectors

    Science.gov (United States)

    Garcia, C. P.; Medina, C. R.; Protz, C. S.; Kenny, R. J.; Kelly, G. W.; Casiano, M. J.; Hulka, J. R.; Richardson, B. R.

    2016-01-01

    As part of the Combustion Stability Tool Development project funded by the Air Force Space and Missile Systems Center, the NASA Marshall Space Flight Center was contracted to assemble and hot-fire test a multi-element integrated test article demonstrating combustion characteristics of an oxygen/hydrocarbon propellant oxidizer-rich staged-combustion engine thrust chamber. Such a test article simulates flow through the main injectors of oxygen/kerosene oxidizer-rich staged combustion engines such as the Russian RD-180 or NK-33 engines, or future U.S.-built engine systems such as the Aerojet-Rocketdyne AR-1 engine or the Hydrocarbon Boost program demonstration engine. On the current project, several configurations of new main injectors were considered for the thrust chamber assembly of the integrated test article. All the injector elements were of the gas-centered swirl coaxial type, similar to those used on the Russian oxidizer-rich staged-combustion rocket engines. In such elements, oxidizer-rich combustion products from the preburner/turbine exhaust flow through a straight tube, and fuel exiting from the combustion chamber and nozzle regenerative cooling circuits is injected near the exit of the oxidizer tube through tangentially oriented orifices that impart a swirl motion such that the fuel flows along the wall of the oxidizer tube in a thin film. In some elements there is an orifice at the inlet to the oxidizer tube, and in some elements there is a sleeve or "shield" inside the oxidizer tube where the fuel enters. In the current project, several variations of element geometries were created, including element size (i.e., number of elements or pattern density), the distance from the exit of the sleeve to the injector face, the width of the gap between the oxidizer tube inner wall and the outer wall of the sleeve, and excluding the sleeve entirely. This paper discusses the design rationale for each of these element variations, including hydraulic, structural

  9. Review: Circulation of Inorganic Elements in Combustion of Alternative Fuels in Cement Plants

    DEFF Research Database (Denmark)

    Cortada Mut, Maria del Mar; Nørskov, Linda Kaare; Jappe Frandsen, Flemming

    2015-01-01

    Cement production is an energy-intensive process, which traditionally has been dependent on fossil fuels. However, the use of alternative fuels, i.e., selected waste, biomass, and byproducts with recoverable calorific value, is constantly increasing. Combustion of these fuels is more challenging...... the internal circulation of S, Cl, Na, and K. Compounds containing these elements, such as alkali salts, evaporate when exposed to high temperatures and subsequently condense in colder parts of the plant. The transformation of the volatile inorganic species at different locations in the cement plant...... cycles of inorganic elements that are established within the cement plant and their dependence on process parameters. Special focus is given to the sulfur cycle. This cycle is intensified by CaSO4 decomposition, making it sensitive to local reducing conditions....

  10. Fission product determination in irradiated fuel processing waste (electrophoresis); Dosage des produits de fission dans les effluents de traitement des combustibles irradies (electrophorese)

    Energy Technology Data Exchange (ETDEWEB)

    Auchapt, J M; Tret, J [Commissariat a l' Energie Atomique, Centre de Marcoule, 30 - Bagnols-sur-Ceze (France). Centre de Production de Plutonium de Marcoule. Services d' Extraction du Plutonium

    1966-07-01

    This dosage method concerns fission products present in the waste produced from the processing of cooled irradiated fuels. - Sr, Cs, Ce, Y, Ru by quantitative analysis; - Zr, Nb by qualitative analysis. It includes electrophoresis on paper strips one meter long which is then analysed between two window-less Geiger counters. For an activity of 10{sup -2} {mu}Ci of any cation in a 10 {mu}l spot, the standard error {sigma} if 3 to 4 per cent. complete analysis lasts about 5 hours. (authors) [French] Cette methode de dosage concerne les produits de fission presents dans les effluents de traitement des combustibles irradies refroidis: - Sr, Cs, Ce, Y, Ru en analyse quantitative; - Zr, Nb en analyse qualitative. Elle comporte une electrophorese sur bande de papier de un metre de longueur suivie d'un depouillement entre deux compteurs Geiger sans fenetre. Pour une activite de 10{sup -2} {mu}Ci d'un cation quelconque dans une tache de 10 {mu}l l'erreur standard {sigma} est de 3 a 4 pour cent. L'analyse complete demande environ 5 heures. (auteurs)

  11. Techniques de combustion Combustin Techniques

    Directory of Open Access Journals (Sweden)

    Perthuis E.

    2006-11-01

    Full Text Available L'efficacité d'un processus de chauffage par flamme est étroitement liée à la maîtrise des techniques de combustion. Le brûleur, organe essentiel de l'équipement de chauffe, doit d'une part assurer une combustion complète pour utiliser au mieux l'énergie potentielle du combustible et, d'autre part, provoquer dans le foyer les conditions aérodynamiques les plus propices oux transferts de chaleur. En s'appuyant sur les études expérimentales effectuées à la Fondation de Recherches Internationales sur les Flammes (FRIF, au Groupe d'Étude des Flammes de Gaz Naturel (GEFGN et à l'Institut Français du Pétrole (IFP et sur des réalisations industrielles, on présente les propriétés essentielles des flammes de diffusion aux combustibles liquides et gazeux obtenues avec ou sans mise en rotation des fluides, et leurs répercussions sur les transferts thermiques. La recherche des températures de combustion élevées conduit à envisager la marche à excès d'air réduit, le réchauffage de l'air ou son enrichissement à l'oxygène. Par quelques exemples, on évoque l'influence de ces paramètres d'exploitation sur l'économie possible en combustible. The efficiency of a flame heating process is closely linked ta the mastery of, combustion techniques. The burner, an essential element in any heating equipment, must provide complete combustion sa as to make optimum use of the potential energy in the fuel while, at the same time, creating the most suitable conditions for heat transfers in the combustion chamber. On the basis of experimental research performed by FRIF, GEFGN and IFP and of industrial achievements, this article describesthe essential properties of diffusion flames fed by liquid and gaseous fuels and produced with or without fluid swirling, and the effects of such flames on heat transfers. The search for high combustion temperatures means that consideration must be given to operating with reduced excess air, heating the air or

  12. Particulate matter emissions, and metals and toxic elements in airborne particulates emitted from biomass combustion: The importance of biomass type and combustion conditions.

    Science.gov (United States)

    Zosima, Angela T; Tsakanika, Lamprini-Areti V; Ochsenkühn-Petropoulou, Maria Th

    2017-05-12

    The aim of this study was to investigate the impact of biomass combustion with respect to burning conditions and fuel types on particulate matter emissions (PM 10 ) and their metals as well as toxic elements content. For this purpose, different lab scale burning conditions were tested (20 and 13% O 2 in the exhaust gas which simulate an incomplete and complete combustion respectively). Furthermore, two pellet stoves (8.5 and 10 kW) and one open fireplace were also tested. In all cases, 8 fuel types of biomass produced in Greece were used. Average PM 10 emissions ranged at laboratory-scale combustions from about 65 to 170 mg/m 3 with flow oxygen at 13% in the exhaust gas and from 85 to 220 mg/m 3 at 20% O 2 . At pellet stoves the emissions were found lower (35 -85 mg/m 3 ) than the open fireplace (105-195 mg/m 3 ). The maximum permitted particle emission limit is 150 mg/m 3 . Metals on the PM 10 filters were determined by several spectrometric techniques after appropriate digestion or acid leaching of the filters, and the results obtained by these two methods were compared. The concentration of PM 10 as well as the total concentration of the metals on the filters after the digestion procedure appeared higher at laboratory-scale combustions with flow oxygen at 20% in the exhaust gas and even higher at fireplace in comparison to laboratory-scale combustions with 13% O 2 and pellet stoves. Modern combustion appliances and appropriate types of biomass emit lower PM 10 emissions and lower concentration of metals than the traditional devices where incomplete combustion conditions are observed. Finally, a comparison with other studies was conducted resulting in similar results.

  13. DOSAGE DES ELEMENTS EN TRACE DES CALCAIRES AU SERVICE DE L'ARCHEOLOGIE

    International Nuclear Information System (INIS)

    BLANC, A.; HOLMES, L.; HARBOTTLE, G.

    1998-01-01

    Numerous quarries in the Lutetian limestone formations of the Paris Basin provided stone for the building and the decoration of monuments from antiquity to the present. To determine the origin of stone used for masonry and sculptures in these monuments, a team of geologists and archaeologists has investigated 300 quarries and collected 2,300 samples. Petrographic and paleontologic examination of thin sections allows geologists to distinguish Lutetian limestones from Jurassic and Cretaceous limestones. Geologists also seek to formulate hypotheses regarding the origin of Lutetian limestones used for building and sculpture in the Paris region. In the search for the sources of building and sculptural stone, the analytical methods of geologists are limited because often several quarries produce the same lithofacies. A new tool is now available, however, to attack questions of provenance raised by art historians. Because limestones from different sources have distinctive patterns of trace-element concentrations, compositional analysis by neutron activation allows them to compare building or sculptural stone from one monument with stone from quarries or other monuments. This analytical method subjects a powdered limestone sample to standard neutron activation analysis procedures at Brookhaven National Laboratory. With the help of computer programs, the compositional fingerprints of Lutetian limestones can be determined and stored in a database. The limestone database contains data for approximately 2,100 samples from monuments, sculptures and quarries. It is particularly rich in samples from the Paris Basin

  14. Critical experiments in AQUILON with fuels slightly enriched in uranium 235 or in plutonium; Experiences critiques dans aquilon portant sur des combustibles legerement enrichis en uranium 235 et en plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Chabrillac, M; Ledanois, G; Lourme, P; Naudet, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    Reactivity comparisons have been, made in Aquilon II between geometrically identical lattices differing only by the composition of the fuel. The fuel elements consist in metallic uranium single rods with either slight differences of the isotopic composition (0.69 - 0.71 - 0.83 - 0.86 per cent of uranium 235) or slight additions of plutonium (0.043 per cent). Five lattices pitches have bean used, in order to produce a large variation of spectrum. Two additional sets of plutonium fuels are prepared to be used in the same conditions. The double comparisons: natural enriched 235 versus natural-enriched plutonium are made in such a way that a very precise interpretation is permitted. The results are perfectly consistent which seems to prove that the calculation methods are convenient. Further it can been inferred that the usual data, namely for the ratio of the {eta} of {sup 235}U and {sup 239}Pu seem reliable. (authors) [French] On a compare neutroniquement dans Aquilon II des reseaux geometriquement identiques mais comportant de petites differences de composition du combustible. EL s'agit de barres d'uranium metallique, les unes avec des teneurs differentes en isotopes 235 (0,69 - 0,71 - 0,83 - 0,86 pour cent) les autres comportant une legere addition de plutonium (0,043 pour cent). Les comparaisons ont ete faites a cinq pas differents, de maniere a mettre en jeu une assez large variation de spectre. Deux autres jeux de combustible au plutonium seront utilises ulterieurement dans les memes conditions. Les resultats des mesures se presentent sous forme de doubles comparaisons: naturel-enrichi 235/naturel-enrichi plutonium. On s'est place dans des conditions qui permettent des interpretations tres precises. Les resultats sont remarquablement coherents, ce qui semble montrer que les methodes de calcul sont bien adaptees, Ils tendent d'autre part a prouver que les valeurs numeriques admises dans la litterature, notamment pour le rapport des {eta} de l'U 235 et de Pu 239

  15. Evolution des modèles mathématiques directs appliqués aux moteurs à combustion interne Evolution of Direct Mathematical Models Applied to Internal-Combustion Engines

    Directory of Open Access Journals (Sweden)

    Rumiano N.

    2006-11-01

    Full Text Available Cet article rend compte de l'évolution présente et future des modèles mathématiques directs de simulation dans les moteurs. Ceux-ci sont basés sur la résolution des équations de Navier-Stokes, et deviennent peu à peu une nécessité surtout en ce qui concerne la combustion hétérogène. Après un aperçu sur l'état actuel des algorithmes de calcul et des sous-modèles physiques utilisés, on présente une revue des principaux codes de calcul appliqués au moteur, avec quelques-uns de leurs résultats. Après avoir évoqué les obstacles rencontrés lors de leur mise en oeuvre, on aborde l'évolution prévisible lors des prochaines années, tant pour les techniques de calcul que pour les codes eux-mêmes. This article describes the present and future evolution of direct mathematical models used for engine simulation. These models are based on the solving of Navier-Stokes equations and are gradually becoming an absolute necessity, especially with regard to heterogeneous combustion. Alter briefly describing the present state of the computing algorithms and physical submodels used, the leading computing codes applied to engines are reviewed, with some of their results. Then the stumbling blocks encountered during the implementation of these codes are described, followed by the foresable evolution in the next few years, for both computing techniques and the codes themselves.

  16. Fuel slugs considered for use in the high flux reactor EL3; Elements combustibles envisages pour la pile a haut flux EL 3

    Energy Technology Data Exchange (ETDEWEB)

    Stohr, J A; Caillat, R; Gauthron, M; Montagne, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    EL3 was designed essentially for the study, under irradiation conditions, of materials used in the construction of atomic reactors. The study schedule allocates considerable time and effort to new types of fuel slugs. The present report described the various types of slug being tested or scheduled for tests. After laboratory study, each slug is tested in an experimental cell in the pile. The best are retained and used to charge the reactor (the present charge is purely provisional to permit first criticality and power rise tests)ren. [French] La pile EL3 est essentiellement destinee a l'etude sous irradiation des materiaux utilises dans la construction des reacteurs atomiques. Dans ce programme, une tres large part est reservee a l'etude de nouveaux elements combustibles. Le present rapport decrit les differentes solutions de cartouches dont l'essai est envisage ou en cours. Apres etude en laboratoire, chacune de ces solutions est testee dans une cellule experimentale en pile. Les meilleures seront retenues pour constituer le chargement normal de la pile (le chargement actuel etant essentiellement une solution provisoire qui a permis la divergence de la pile et les premiers essais de montee en puissance). (auteur)

  17. Elemental and organic carbon in flue gas particles of various wood combustion systems

    Energy Technology Data Exchange (ETDEWEB)

    Gaegauf, C.; Schmid, M.; Guentert, P.

    2005-12-15

    The airborne particulate matter (PM) in the environment is of ever increasing concern to authorities and the public. The major fractions of particles in wood combustion processes are in the size less than 1 micron, typically in the range of 30 to 300 nm. Of specific interest is the content of the elemental carbon (EC) and organic carbon (OC) in the particles since these substances are known for its particular potential as carcinogens. Various wood combustion systems have been analysed (wood chip boiler, pellet boiler, wood log boiler, wood stove and open fire). The sampling of the particles was done by mean of a multi-stage particle sizing sampler cascade impactor. The impactor classifies the particles collected according to their size. The 7 stages classify the particles between 0.4 and 9 microns aerodynamic diameter. The analytical method for determining the content of EC and OC in the particles is based on coulometry. The coulometer measures the conductivity of CO{sub 2} released by oxidation of EC in the samples at 650 {sup o}C. The OC content is determined by pyrolysis of the particle samples in helium atmosphere.

  18. Development of Non-Metallic Fuel Elements for a High-Temperature Gas-Cooled Reactor; Mise au point d'elements combustibles non metalliques pour un reacteur a haute temperature, refroidi par un gaz; Razrabotka nemetallicheskikh teplovydelyashchikh ehlementov dlya vysokotemperaturnogo reaktora s gazovym okhlazhdeniem; Elementos combustibles no metalicos para un reactor de temperatura elevada refrigerado por gas

    Energy Technology Data Exchange (ETDEWEB)

    Liebmann, B.; Schafer, L.; Spener, G. [NUKEM, Nuklear-Chemie und -Metallurgie G.m.b.H., Wolfgang bei Hanau, Federal Republic of Germany (Germany)

    1963-11-15

    In connection with fuel element development work for the high-temperature gas-coolcd reactor of the Brown-Boveri/Krupp Reaktorbau G.m.b.H., two different fuel element concepts were considered and developed. In both cases the fuel element consists of a graphite ball of 6 cm in diam. which contains the fuel insert, a cylindrical pellet of about 20 mm in diam. and 16 mm in height. The two concepts differ in the type of the.fuel insert as well as in the preparation of the graphite ball. In the first concept the fuel insert consists of a mixture of UC{sub 2} and graphite which is prepared by blending U{sub 3}O{sub 8} and graphite, pressing them into pellets and reacting the two components in a vacuum furnace at 1800{sup o}C. The atomic ratio of U : C is 1:45. Since this type of fuel pellet does not retain the fission products completely the surrounding graphite sphere had to be made impervious to fission products by impregnation in order to obtain a fission-product retaining element. Permeabilities of the order of 10{sup -6}cm{sup 2}/s could be achieved. In the second concept the fuel insert consists of a solid solution of UC in ZrC and is coated with a layer of ZrC. The molar ratio of UC to ZrC is 1 : 20. The fuel pellet preparation was accomplished by the following procedure: UO{sub 2}, ZrO{sub 2}, and graphite were mixed and pressed into pellets. The pellets were reacted to the carbides. Ball milling of the carbides was followed by hot pressing at temperatures o f 2000{sup o}C. Densities of more than 95% of the theoretical density could be achieved. A full description of the preparation and of some physical properties of the fuel pellets is given in the paper. A sufficient fission gas retention behaviour of this type of fuel insert which allows it to be put into unimpregnated graphite balls is expected. Other advantages of this kind of fuel are discussed. (author) [French] Dans le cadre des etudes de combustibles destines au reacteur a haute temperature, refroidi par

  19. Fuel location, homogeneity and amount in flat and tubular configurations; Repartition, Homogeneite et Quantite du Combustible dans les Elements a Configuration Plate ou Tubulaire; Polozhenie, gomogennost' i kolichestvo topliva v ploskikh i trubchatykh konfiguratsiyakh; Disposicion, Homogeneidad y Cantidad de Combustibles en Configuraciones Planas y Tubulares

    Energy Technology Data Exchange (ETDEWEB)

    Meester, P. de [Studiecentrum voor Kernenergie, Mol (Belgium)

    1965-10-15

    standards are considered. Accuracy and elimination of errors are discussed. Some possible future improvements in the tests are proposed. (author) [French] Les elements combustibles pour le reacteur d'essai de materiaux BR-2 peuvent etre-realises, soit avec des plaques obtenues par cadrages, soit avec des tubes obtenus par coextrusion. Au cours de la fabrication et avant le chargement dans le reacteur, il faut verifier ou mesurer la repartition, l'homogeneite et la quantite du combustible. Il faut connaitre la repartition du combustible pour le positionnement de l'ame dans les plaques et tubes ainsi que pour une premiere evaluation qualitative du produit du point de vue des specifications geometriques. On a procede a des radiographies 3 80-90 keV, ainsi qu'a des autoradiographies et gammagraphies avec une source au thulium-170. Pour l'examen radiographique des tubes de combustible, on a introduit dans le tube un mandrin en plomb auquel etait fixe un film sensible aux rayons X , puis on a fait des radiographies sous divers angles. En utilisant une source radioactive se deplacant le long de l'axe du tube et un film place autour du tube, on a obtenu des enregistrements avec un tres bon contraste. Il faut controler l'homogeneite du combustible pour assurer la securite du fonctionnement du reacteur, c'est-a-dire pour eviter toute concentration excessive de combustible pouvant donner lieu a des formations de vapeur pendant le fonctionnement du reacteur et pour garantir que le chargement de combustible est suffisant et regulierement reparti. On peut faire appel a des radiographies en vue d'une verification visuelle. Cependant, s'il est necessaire de faire une analyse quantitative, il est preferable d'utiliser un spectrometre g a m m a a scintillation permettant de mesurer le rayonnement propre emis par l'uranium-235. Le memoire contient une' analyse des resultats obtenus pour quelque 400 plaques de combustible et pour un premier lot de tubes de combustible. Il est possible de

  20. Optimization of Gas Turbine Cogeneration Systemfor Various Heat Exchanger Configurations Optimisation des systèmes de turbine à combustion en cogénération pour différentes configurations des échangeurs de chaleur

    Directory of Open Access Journals (Sweden)

    Costea M.

    2011-11-01

    Full Text Available The present paper investigates and compares the performance of three configurations of Gas Turbine systems allowing cogeneration of heat and electricity, on the basis of an irreversible regenerative Brayton-Joule cycle. The proposed model is developed for two different cycle constraints, namely, an imposed heat transfer rate released by the fuel combustion, or an imposed maximum cycle temperature. The model also includes the irreversibility due to the friction in the compressor and turbine, and due to the heat losses in the combustion chamber and heat exchangers. Energy efficiency for the system without and with cogeneration, and the exergetic efficiency are used in order to emphasize the cogeneration advantages, but also to help the designer to choose the best configuration of the Gas Turbine system that suits to his needs. Experimental data from a real operating microturbine were used to validate the model. The power output and the energy and exergetic efficiencies are optimized with respect to a set of operating parameters. The optimum values of the Gas Turbine engine parameters corresponding to maximum power output and respectively to maximum thermodynamic efficiency are discussed. The results show same optimal values of the compression ratio corresponding to almost all maximum performances for an imposed heat transfer rate released by the fuel combustion, excepting the maximum exergetic efficiency that requires higher optimal values of the compression ratio than the maximum exergy rate one. A performance comparison of the three configurations is done and future perspectives of the work are proposed. Cet article explore et compare les performances des trois configurations de systèmes de turbine à combustion permettant la production combinée de chaleur et d’électricité, sur la base du cycle irréversible régénératif de Brayton-Joule. Le modèle proposé est développé pour deux contraintes différentes sur le cycle, notamment le

  1. Elemental analysis of ash residue from combustion of CCA treated wood waste before and after electrodialytic extraction

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Ottosen, Lisbeth M.

    2006-01-01

    Element distribution in a combined fly ash and bottom ash from combustion of copper chromate arsenate (CCA) treated wood waste was investigated by scanning electron microscopy (SEM/EDX) before and after electrodialytic extraction. The untreated ash contained various particles, including pieces...... of incompletely combusted wood rich in Cr and Ca, and irregular particles rich in Si, Al and K. Cr was also found incorporated in silica-based matrix particles. As was associated with Ca in porous (char) particles, indicating that Ca-arsenates had been formed during combustion. Cu was associated with Cr...... in the incompletely combusted wood pieces and was also found in almost pure form in a surface layer of some matrix particles – indicating surface condensation of volatile Cu species. In treated ash, Ca and As were no longer found together, indicating that Ca-arsenates had been dissolved due to the electrodialytic...

  2. Some aspects of emission and volatization of trace elements on coal combustion

    International Nuclear Information System (INIS)

    Sanchez, J.C.D.; Formoso, M.L.L.; Bristoti, A.

    1987-01-01

    The present research work was carried out an industrial plant which uses a mixture of coals from Leao and Recreio mines for steam generation in a bioler with a capacity of 160t/h of steam. Coal samples from Leao, Recreio and the correspondent mixture were taken, as well as samples from the products of combustion. The present study fundamentally aims at assessing the emission of trace elements and major components of mineral matter, present in coal, in order to bring subsidies for a more efficient control over atmospheric, terrestrial and water pollution. Emissions of trace elements: As, B, Be, Cd, Cl, Co, Cr, Cu, F, Ga, Hg, Mn, Mo, Ni, Pb, S, Sn, V, Zn, Zr, and major elements: Si, Al, Ca, Mg, Ti, Fe, K and P, were calculated. Moreover, the average emission of particulate matter to the atmosphere was evaluated. In the present work, analytical procedures as X-ray spectroscopy and absorption spectroscopy and techniques used for the determination of F and Cl in Brazilian coals are cited. (author) [pt

  3. Element partitioning in combustion- and gasification-based waste-to-energy units

    International Nuclear Information System (INIS)

    Arena, Umberto; Di Gregorio, Fabrizio

    2013-01-01

    Highlights: ► Element partitioning of waste-to-energy units by means of a substance flow analysis. ► A comparison between moving grate combustors and high temperature gasifiers. ► Classification of key elements according to their behavior during WtE processes. ► Slags and metals from waste gasifiers are completely and immediately recyclable. ► Potential reduction of amounts of solid residue to be sent to landfill disposal. - Abstract: A critical comparison between combustion- and gasification-based waste-to-energy systems needs a deep knowledge of the mass flows of materials and elements inside and throughout the units. The study collected and processed data from several moving grate conventional incinerators and high-temperature shaft gasifiers with direct melting, which are in operation worldwide. A material and substance flow analysis was then developed to systematically assess the flows and stocks of materials and elements within each waste-to-energy unit, by connecting the sources, pathways, and intermediate and final sinks of each species. The patterns of key elements, such as carbon, chloride and heavy metals, in the different solid and gaseous output streams of the two compared processes have been then defined. The combination of partitioning coefficients with the mass balances on atomic species and results of mineralogical characterization from recent literatures was used to estimate a composition of bottom ashes and slags from the two types of waste-to-energy technologies. The results also allow to quantify some of the performance parameters of the units and, in particular, the potential reduction of the amount of solid residues to be sent to final disposal

  4. Real-time modelling of the diesel engine combustion process; Echtzeitfaehige Modellierung des dieselmotorischen Verbrennungsprozesses

    Energy Technology Data Exchange (ETDEWEB)

    Merz, B.

    2008-07-01

    The publication investigates single-zone models of diesel engine combustion which are capable, in addition to pre-injection and main injection, to represent post-injection processes on a physical basis. These must function in real time as they are used in ''hardware-in-the-loop'' test stands. Methods to adapt the models to other engine types are explained. Validation is made across the whole characteristic field on the basis of measured data provided by two serial engines. For assessing pollutant production, models are integrated that are capable of calculating NOx and soot formation. These, too, are calculated in real time using appropriate hardware systems. A runtime analysis compares the computing times of the models. (orig.)

  5. Structural elements of mechanical engineering 2. Power train elements. 6. ed.; Konstruktionselemente des Maschinenbaus 2. Grundlagen von Maschinenelementen fuer Antriebsaufgaben

    Energy Technology Data Exchange (ETDEWEB)

    Steinhilper, W. [Kaiserslautern Univ. (Germany). Lehrstuhl fuer Maschinenelemente und Getriebetechnik; Sauer, B. (eds.) [Technische Univ. Kaiserslautern (Germany). Lehrstuhl fuer Maschinenelemente und Getriebetechnik

    2008-07-01

    The Steinhilper/Roeper textbooks have become standard textbooks of German technical universities. This is the 6th edition, published under the new name 'Structural elements of mechanical engineering' by Steinhilper/Sauer, a renowned team of expert authors, has been completely revised and re-edited. In Vol. 2, the standard chapters on friction, wear, lubrication, bearings, sliding bearings, rolling bearings, and seals, have been completely updated. There are new chapters on: Power train systems, transmission systems and brakes, toothed gears and toothed gear drives, traction drives, friction transmission, sensors and actuators. The two-volume textbook covers the whole spectrum of typical elements of mechanical engineering. The information, much of which goes deeper than just basic knowledge, addresses students of universities and technical universities. This makes the book also a useful reference manual for the daily work of practical engineers. (orig.) [German] Die Baende der Maschinen- und Konstruktionselemente von Steinhilper/Roeper haben sich als Standard-Lehrbuecher an Technischen Hochschulen durchgesetzt. Unter dem Titel Steinhilper/Sauer: Konstruktionselemente des Maschinenbaus wurde das Werk von einem ausgewiesenen Autorenteam aktualisiert und grundlegend ueberarbeitet. Im vorliegenden Band 2 sind die bisherigen Kapitel Reibung, Verschleiss und Schmierung, Lagerungen, Gleitlager und Waelzlager sowie Dichtungen komplett ueberarbeitet. Neu hinzu gekommen sind: Einfuehrung in Antriebssysteme, Kupplungen und Bremsen, Zahnraeder und Zahnradgetriebe, Zugmittelgetriebe, Reibradgetriebe sowie Sensoren und Aktoren. Die 6. Auflage stellt eine aktualisierte und berichtigte Fassung dar. Die beiden Baende des Lehrwerks umfassen das gesamte Spektrum der typischen Konstruktions- und Maschinenelemente. Die Inhalte sind auf die Ausbildung an Universitaeten und Technischen Hochschulen abgestimmt und gehen teilweise ueber das Grundlagenwissen hinaus. So stellen die

  6. The reprocessing of irradiated fuels by halides and their compounds; Le traitement des combustibles irradies par les halogenes et leurs composes

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, M; Faugeras, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    A brief description is given of the experiments leading to the choice of the process volatilization of fluorides by gas phase attack. The chemical process is described for certain current types of clad Fuels: the aluminium or the zirconium cladding is first volatilized as chloride by attack with gaseous hydrogen chloride. The uranium is then transformed into volatile hexafluoride by attack with fluorine. These reactions are carried out consecutively in the same reactor in the presence of a fluidized bed of alumina which facilitates heat exchange. The experiments have been carried out in quantities from 100 gms to several kilograms of fuel, first without activity, and then with tracers. A description is given of the laboratory research which was carried out simultaneously on the separation of uranium and plutonium fluorides. Finally, an apparatus is described which is intended to test the process on irradiated fuel at an activity level of several thousands of curies of fission products. (authors) [French] On rappelle brievement les experimentations qui nous ont permis de decider du procede adopte volatilisation des fluorures par attaque en phase gazeuse. On decrit le processus chimique pour certains types courants de combustibles Gaines: dans un premier stade, l'aluminium ou le zirconium est volatilise sous forme de chlorure par action de l'acide chlorhydrique. Ensuite, l'uranium est transforme en hexafluorure volatil par action du fluor. Ces operations se font successivement dans un meme reacteur, en presence d'un lit fluidise d'alumine qui a pour but de faciliter les echanges thermiques. L'experimentation a ete conduite sur des quantites allant de 100 g a plusieurs kg de combustibles, en inactif, puis avec des traceurs. On decrit les etudes de laboratoire menees parallelement sur la separation des fluorures d'uranium et de plutonium. Enfin, on decrit une installation en construction destinee a experimenter le procede sur combustible irradie, a l'echelle de

  7. The synergistic effect in coal/biomass blend briquettes combustion on elements behavior in bottom ash using ICP-OES

    Energy Technology Data Exchange (ETDEWEB)

    Lazaroiu, G.; Frentiu, T.; Maescu, L.; Mihaltan, A.; Ponta, M.; Frentiu, M.; Cordos, E. [Universitatea Politehnica din Bucuresti, Bucharest (Romania)

    2009-05-15

    This paper focuses on the study of the synergistic effect in coal/biomass blend briquettes combustion on behavior of Al, As, Ba, Cd, Co. Cr, Cu, Fe, Ga, K, Mn, Mo, Ni, P, Pb, Si, V, W, Zn, Zr and characterization of raw materials and bottom ashes. The manufacturing of coal/biomass briquettes although not commonly used is an attractive approach, as briquettes combustion is more technologically advantageous than the fluidized bed combustion. In the same time this technology is a way to render valuable materials of low calorific power and results in diminishing polluting emission. Raw materials and briquettes from different blends of pitcoal/sawdust were subjected to combustion in a 55 kW-boiler. The total content of elements after digestion in the HNO{sub 3} - HF mixture and the content in water leachate at a solid/liquid ratio of 1:2 were determined both in raw materials and bottom ash by ICP-OES. The total content of elements was higher in pitcoal than in sawdust. The synergistic effect depends both on coal/biomass ratio in blend and element nature. The water leachable fraction of elements from ash decreased along with the increase of sawdust weight excepting macronutrients (K, P) and Si.

  8. Presence de Carbone-13 dans les elements combustibles de type (U,Pu)O 2 irradies en reacteur rapide

    Science.gov (United States)

    Kryger, Bernard; Hagemann, Robert

    1982-06-01

    Du carbone-13 produit par la réaction de capture neutronique 168O + 10n → 136C + 42He se forme dans les combustibles de type oxyde irradiés en neutrons rapides. Cette réaction, dont le seuil d'énergie se situe à 2.35 MeV, conduit à la formation d'une quantité de carbone-13 qui peut varier notablement suivant le spectre neutronique du réacteur (entre 20 et 40 × 10 -6g 13C/g (U,Pu)O 2 pour une fluence de 2 × 10 23 n/cm 2). DES mesures effectuées sur le combustible et la gaine par spectrométrie de masse après irradiation montrent qu'une fraction égale ou supérieure à la moitié du carbone-13 produit dans l'oxyde peut être transférée dans la gaine. Un tel comportement nous fait considérer le carbone-13 comme un véritable marqueur du carbone plus généralement contenu dans l'oxyde et, à ce titre, la détection de cet isotope devrait contribuer à élucider tout particulièrement les mécanismes de carburation de la gaine par les combustibles (U,Pu)O 2 des réacteurs surgénérateurs.

  9. Trends in the Rare Earth Element Content of U.S.-Based Coal Combustion Fly Ashes.

    Science.gov (United States)

    Taggart, Ross K; Hower, James C; Dwyer, Gary S; Hsu-Kim, Heileen

    2016-06-07

    Rare earth elements (REEs) are critical and strategic materials in the defense, energy, electronics, and automotive industries. The reclamation of REEs from coal combustion fly ash has been proposed as a way to supplement REE mining. However, the typical REE contents in coal fly ash, particularly in the United States, have not been comprehensively documented or compared among the major types of coal feedstocks that determine fly ash composition. The objective of this study was to characterize a broad selection of U.S. fly ashes of varied geological origin in order to rank their potential for REE recovery. The total and nitric acid-extractable REE content for more than 100 ash samples were correlated with characteristics such as the major element content and coal basin to elucidate trends in REE enrichment. Average total REE content (defined as the sum of the lanthanides, yttrium, and scandium) for ashes derived from Appalachian sources was 591 mg kg(-1) and significantly greater than in ashes from Illinois and Powder River basin coals (403 and 337 mg kg(-1), respectively). The fraction of critical REEs (Nd, Eu, Tb, Dy, Y, and Er) in the fly ashes was 34-38% of the total and considerably higher than in conventional ores (typically less than 15%). Powder River Basin ashes had the highest extractable REE content, with 70% of the total REE recovered by heated nitric acid digestion. This is likely due to the higher calcium content of Powder River Basin ashes, which enhances their solubility in nitric acid. Sc, Nd, and Dy were the major contributors to the total REE value in fly ash, based on their contents and recent market prices. Overall, this study shows that coal fly ash production could provide a substantial domestic supply of REEs, but the feasibility of recovery depends on the development of extraction technologies that could be tailored to the major mineral content and origins of the feed coal for the ash.

  10. Contribution to the study of the fission-gas release in metallic nuclear fuels; Contribution a l'etude du degagement des gaz de fission dans les combustibles nucleaires metalliques

    Energy Technology Data Exchange (ETDEWEB)

    Kryger, B [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-10-01

    In order to study the effect of an external pressure on the limitation of swelling due to fission-gas precipitation, some irradiations have been carried out at burn-ups of about 35.000 MWd/ton, and at average sample temperatures of 575 Celsius degrees, of non-alloyed uranium and uranium 8 per cent molybdenum gained in a thick stainless steel can. A cylindrical central hole allows a fuel swelling from 20 to 33 per cent according to the experiment. After irradiation, the uranium samples showed two types of can rupture: one is due to the fuel swelling, and the other, to the pressure of the fission gases, released through a network of microcracks. The cans of the uranium-molybdenum samples are all undamaged and it is shown that the gas release occurs by interconnection of the bubbles for swelling values higher than those obtained in the case of uranium. For each type of fuel, a swelling-fission gas release relationship is established. The results suggest that good performances with a metallic fuel intended for use in fast reactor conditions can be obtained. (author) [French] Afin d'etudier l'effet d'une pression exterieure sur la limitation du gonflement due a la precipitation des gaz de fission, on a irradie a des taux de combustion d'environ 35.000 MWj/t et a des temperatures moyennes de 575 degres des echantillons d'uranium non allie et d'uranium-molybdene 8 pour cent contenus dans une gaine en acier inoxydable epaisse. Un trou cylindrique central permet au combustible de gonfler librement de 20 a 33 pour cent suivant les cas. Apres irradiation les echantillons d'uranium presentent deux types de ruptures de gaine: l'une due au gonflement du combustible, l'autre a la pression des gaz degages, ce degagement des gaz etant provoque par un reseau de micro-fissures. Les gaines des echantillons d'alliage uranium-molybdene sont toutes intactes et l'on montre que le relachement des gaz opere par interconnexion des bulles pour des valeurs de gonflement plus elevees que dans

  11. Trace elements partitioning during coal combustion in fluidized bed under O{sub 2}/CO{sub 2} atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haixin; Zhao, Changsui; Liang, Cai; Duan, Lunbo; Chen, Huichao [Southeast Univ., Nanjing (China). School of Energy and Environment

    2013-07-01

    Experiments were conducted to investigate the effects of temperature and O{sub 2}/CO{sub 2} atmosphere on trace elements (Cr, Mn, Co, Ni, Cd, Pb, Hg, As, Se) partitioning during combustion of Xuzhou bituminous coal in a 6 kWth fluidized bed. Inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS) were used to determine trace elements contents in raw coal, bottom ash, fly ash and flue gas. The results indicate that with bed temperature increase, the relative enrichment of all the trace elements except Cr in bottom ash decreases suggesting that their volatility is enhanced. The relative enrichments of hardly volatile elements, like Cr and Mn in fly ash increase with bed temperature increase while those of partially volatile and highly volatile elements in fly ash are opposite. The relative enrichments of trace elements except Cr and Mn in fly ash are higher than those in bottom ash. Increasing bed temperature promotes elements like As, Se and Hg to migrate to vapor phase, Mn to migrate to fly ash and Cr to migrate to both bottom ash and fly ash. 21%O{sub 2}/79%CO{sub 2} atmosphere improves the volatility of Cr, Mn, Co, Se and their migration to fly ash, while restrains the volatility of As, Ni, Pb. It has little effect on the volatility of Hg but improves its migration to fly ash. Mass balance ratio was also calculated to observe trace elements distribution in bottom ash, fly ash and flue gas. There is no much difference in trace elements distribution between the two atmospheres. It can be seen that the trace elements proportion in fly ash is much greater, and more than 40% of Hg is distributed in the gas phase. Most of Hg and Se volatilize during combustion. The mass balance ratios are 87 {proportional_to} 129% which is considered acceptable.

  12. Results of the project 'combustion modelling' (BKM II); Ergebnisse des Projekts 'Brennkammermodellierung' (BKM II)

    Energy Technology Data Exchange (ETDEWEB)

    Noll, B.; Rachner, M.; Frank, P.; Schmitz, G.; Geigle, K.P.; Meier, W.; Schuetz, H.; Aigner, M. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Stuttgart (Germany). Inst. fuer Verbrennungstechnik; Kessler, R. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Goettingen (Germany). Inst. fuer Aerodynamik und Stroemungstechnik; Lehmann, B. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Koeln (Germany). Inst. fuer Antriebstechnik; Forkert, T. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Koeln (Germany). Simulation und Softwaretechnik

    2002-07-01

    In the year 1996 the spheres of competence of several DLR-Institutes working in the areas of fluid dynamics, reaction kinetics, combustion, numerical methods and laser measuring techniques have been brought together while contributing to the internal DLR project 'combustion chamber modelling (BKM)', in order to proceed with the computational simulation of combustion processes in combustion chambers of gas turbines. The main issue was the development of a research code for numerical simulation of fluid flow in real combustion chambers. Here the development of computational models of physical and chemical processes was emphasized, among other processes the formation of soot was treated. Moreover, a worldwide outstanding database of measured data for the purpose of code validation has been created within the framework of the BKM project using the laboratory facilities of the DLR, which are in Germany unique for the experimental investigation of the various processes in combustion chambers of gas turbines. The project BKM is part of the specific DLR-programme 'energy'. With the successful completion of the first phase of the project in 1998, a second project phase of three years (BKM II) has been launched at the beginning of 1999. Here the work of the first phase continued and new topics were tackled. The second phase of the project was partly founded by the DLR-programme 'aeronautics'. (orig.) [German] Im Jahr 1996 wurden die Faehigkeiten mehrerer DLR-Institute auf den Gebieten Stroemungsmechanik, Reaktionskinetik, Verbrennung sowie Numerische Verfahren und Laser-Messverfahren in dem DLR-internen Projekt 'Brennkammermodellierung' (BKM) zusammengefuehrt, um die rechnerische Simulation der Verbrennungsvorgaenge in Gasturbinen-Brennkammern voranzutreiben. Dabei war die Entwicklung eines Forschungscodes zur numerischen Simulation von realen Brennkammerstroemungen das vorrangige Ziel der Arbeiten. Ein besonderes Schwergewicht lag

  13. Application of a powder sintering-extrusion process to the fabrication of U-Al and UO{sub 2}-stainless steel dispersed fuel elements; Application de frittage-filage de poudres a la fabrication d'elements combustibles disperses U-Al et UO{sub 2} inox

    Energy Technology Data Exchange (ETDEWEB)

    Meny, L.; Buffet, J.; Sauve, Ch.

    1962-07-01

    Within the scope of an investigation of dispersion-type fuel elements, the fabrication by extrusion and sintering of cladded bars and tubes with core of either uranium-aluminum or uranium oxide-stainless steel fuel was investigated. The powder mixtures are first pre-densified in a 'pot', whereupon the sheathed compact is degassed and sealed in a vacuum by electron-beam welding. The subsequent co-extrusion is performed at low temperature and with slow pressure application in the case of U-Al dispersions; and at high temperature with rapid pressure application, using the Ugine-Sejournet process, in the case of UO{sub 2}-stainless steel dispersions. The procedure permits the production of practically fully dense bars and tubes more than 1 m. in length and 10-30 mm in diameter, the wall thickness of the tubes ranging from 2-5 mm. The physical and mechanical characteristics of the dispersion, as well as the mechanical characteristics of the cladded elements, were investigated as a function of the uranium content and the temperature. (authors) [French] Dans le cadre de l'etude des elements combustibles disperses, nous avons etudie la fabrication par frittage-filage de barreaux et de tubes gaines renfermant un noyau combustible soit en uranium-aluminium, soit en UO{sub 2}-inox. Les melanges de poudres sont comprimes dans un 'pot'. La billette composite ainsi obtenue est degazee, fermee et soudee sous vide par bombardement electronique. Le cofilage est ensuite effectue, a basse temperature et sur presse lente pour les disperses U-Al, a haute temperature et sur presse rapide par le procede Ugine-Sejournet pour les disperses UO{sub 2}-inox. Nous avons ainsi obtenu des barres et des tubes de porosite pratiquement nulle de plus de 1 metre de longueur et de 10 a 30 mm de diametre; les epaisseurs des tubes sont comprises entre 2 et 5 mm. Les proprietes physiques et mecaniques des disperses ainsi que les proprietes mecaniques des ensembles gaines, ont ete etudiees en fonction de

  14. Applying Thermodynamics to Fossil Fuels: Heats of Combustion from Elemental Compositions.

    Science.gov (United States)

    Lloyd, William G.; Davenport, Derek A.

    1980-01-01

    Discussed are the calculations of heats of combustions of some selected fossil fuel compounds such as some foreign shale oils and United States coals. Heating values for coal- and petroleum-derived fuel oils are also presented. (HM)

  15. Influence de la nature des fuels lourds sur la qualité de leur combustion Influence of Heavy Fuel Oil Composition on Particulate Emissions

    Directory of Open Access Journals (Sweden)

    Feugier A.

    2006-11-01

    Full Text Available A partir d'études de combustion de fuels lourds numéro 2 effectuées dans une chaudière de 1 MW et dans un foyer de 0,1 MW, on conclut que le résidu de Carbone Conradson (CCR des fuels est un bon indicateur de leur combustibilité, mais qu'il n'est pas suffisant dans tous les cas, c'est-à-dire que pour un même CCR, on peut mesurer des valeurs différentes en indice pondéral. Plusieurs interpréta. tions possibles ont été proposées et vérifiées : a Le résidu de Carbone Conradson, résultat d'une pyrolyse lente, est une procédure qui n'est pas suffisamment représentative des conditions réelles. Or, en soumettant un certain nombre de fuels à une pyrolyse flash (technique de la grille chauffée, on observe une bonne corrélation entre la quantité de résidu résultant et le CCR. Donc, ce dernier reste un bon indicateur de combustibilité. b Pour les fuels ex résidu atmosphérique, ex résidu sous-vide et ex désasphaltage, on détermine de satisfaisantes corrélations entre le CCR et certaines caractéristiques physico-chimiques de la fraction lourde des fuels (point de coupe choisi 450°C : polyaromaticité (mesurée par RMN du Carbone 13, C/H, masse moléculaire. Cependant, les fuels de visco-réduction satisfont à d'autres corrélations, de même que les résidus de vapocraquage. Donc, pour ces classes de fuels, on peut prévoir des anomalies entre indice pondéral et CCR, ce qui est observé dans certains équipements. c On observe que pour une même valeur de CCR, la proportion relative entre fractions légères et fractions lourdes des fuels peut parfois varier très sensiblement avec pour conséquence des modifications dans les cartes de richesse et de température des flammes résultantes, et donc des variations dans les émissions particulaires. L'importance de telles variations dépendra des types de brûleurs et de chambres de combustion dans lesquelles la flamme se développera. On the basis of combustion runs of

  16. Combustion and environment. The answers from the energy and equipment suppliers; Combustion et environnement. Les reponses des fournisseurs d`energie et d`equipements

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This paper is a reprint of an article published in `Energie Plus` magazine which questions the capability of commercial fuels and combustion equipments (central heating plants, burners, turbines and engines) available today of respecting the limit values of pollutant emissions (SO{sub x}, NO{sub x}, CO, dusts) of forthcoming regulations. An analysis of the situation is given separately for the fuels (natural gas, coal, heavy fuels) with a stress on the competition aspects, and for the combustion systems (turbines, diesel and gas engines, central heating plants). (J.S.)

  17. Device for controlling the composition of the mixture burnt in the combustion spaces of an internal combustion engine. Einrichtung zur Regelung der Zusammensetzung des in den Brennraeumen einer Brennkraftmaschine zur Verbrennung kommenden Betriebsgemisches

    Energy Technology Data Exchange (ETDEWEB)

    Latsch, R; Bianchi, V

    1986-07-31

    The purpose of the invention is to create a device by which the extent of the reaction to the control of the composition of the mixture burnt in the combustion spaces of an internal combustion engine can be measured in a sensitive, responsive and safe way, where the position of the elements detecting the reaction should have a relatively small effect on the accuracy of the measurement and the extent of measurement. According to the invention, this problem is solved by the use of 2 thermal sensors connected to a control device (photo-electric diode, photo-electric transistor), one of which acts catalytically and causes the parts of the gas mixture there to react. The thermal sensor output signals are periodically integrated via the piston work and are entered in the control device. The measured temperature is a measure of how far the method of operation of the internal combustion engine has approached its limits. (HWJ).

  18. Volume reduction of waste contaminated by fission product elements and plutonium using molten salt combustion

    International Nuclear Information System (INIS)

    McKenzie, D.E.; Grantham, L.F.; Paulson, R.B.

    1979-01-01

    In the Molten Salt Combustion Process, transuranic or β-γ organic waste and air are continuously introduced beneath the surface of a sodium carbonate-containing melt at a temperature of about 800 0 C. Complete combustion of the organic material to carbon dioxide and steam occurs without the conversion of nitrogen to nitrogen oxides. The noxious gases formed by combustion of the chloride, sulfur or phosphorus content of the waste instantly react with the melt to form the corresponding sodium compounds. These compounds as well as the ash and radionuclides are retained in the molten salt. The spent salt is either fused cast into an engineered disposal container or processed to recover salt and plutonium. Molten salt combustion reduces the waste to about 2% of its original volume. Many reactor or reprocessing wastes which cannot be incinerated without difficulty are readily combusted in the molten salt. A 50 kg/hr molten salt combustion system is being designed for the Radioactive Waste Management Complex at the Idaho National Engineering Laboratory. Construction of the combustor started during 1977, and combustor startup was scheduled for the spring of 1978

  19. Properties of low content uranium-molybdenum alloys which may be used as nuclear fuels; Proprietes des alliages uranium-molybdene de faibles teneurs utilisables comme materiaux combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, J; Decours, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    sont presentees les caracteristiques metallurgiques des alliages uranium-molybdene de teneurs comprises entre 0,5 et 3 pour cent en poids de molybdene. Certains de ces alliages etant utilises dans les piles de puissance EdF, nous indiquons brievement les conditions de fonctionnement demandees aux materiaux combustibles: temperature maximum, gradient de temperature et pression externe. Dans une premiere partie sont etudiees les proprietes structurales des alliages en correlation avec les cinetiques des transformations de phases, nous decrivons les incidences de differents facteurs physico-metallurgiques sur la morphologie et sur la structure cristalline des materiaux: - conditions de solidification et heredite de la structure {gamma}, - vitesse de refroidissement au passage des points de transformation - suppression ou non de la transformation intermediaire {gamma} {yields} {beta} Dans une seconde partie, nous indiquons comment la connaissance des processus des transformations de phase a permis de definir les conditions d'elaboration optimales de ces materiaux sous forme de tubes de combustibles destines aux reacteurs EdF: conditions de coulee traitement de refroidissement controle, soudabilite. Dans une troisieme partie, nous etudions la stabilite thermique au cours de paliers de longue duree a haute temperature et de cycles, dans les deux domaines du diagramme d'equilibre {alpha} + {gamma}, {beta} + {gamma}; les influences de la morphologie (en particulier des deux types de pseudo-grains {alpha} observes) et de la vitesse de refroidissement lors du passage des points de transformation sont discutees. Dans une quatrieme partie, les proprietes mecaniques sont discutees resistance a la traction, resistance au fluage, resilience. Ces proprietes peuvent etre egalement influencees par l'heredite de la structure {gamma} et par la vitesse de refroidissement subie par l'alliage. En conclusion, nous developpons les raisons qui ont motive le choix de certains de ces alliages

  20. Modélisation de la combustion de fuels lourds prenant en compte la dispersion des asphaltènes Modeling Heavy Fuel-Oil Combustion (While Considering Or Including Asphaltene Dispersion

    Directory of Open Access Journals (Sweden)

    Audibert F.

    2006-11-01

    Full Text Available Divers modèles, ayant pour but de prédire le taux d'imbrûlés solides lors de la combustion du fuel lourd, ont été mis au point dans le passé. Les paramètres entrant en ligne de compte sont le plus souvent les teneurs en résidus lourds hydrocarbonés (asphaltènes précipités au pentane ou à l'heptane et carbone Conradson et en métaux : c'est le cas des modèles Exxon et Shell développés respectivement en 1979 et 1981. D'autres modèles tiennent compte, en plus de la composition du fuel, de son mode d'atomisation, de son mode de diffusion dans le foyer et de la cinétique de combustion : on peut citer les travaux du Laboratoire Energie du MIT publiés en 1986. Néanmoins, ces facteurs ne sont pas les seuls à intervenir : l'expérience a montré que l'état de dispersion des asphaltènes peut jouer également un grand rôle, notamment dans le cas d'installations de combustion à injection mécanique, pour lesquelles la dispersion des gouttelettes n'est pas aussi fine que pour des installations munies d'une injection assistée par la vapeur. Cette influence de la dispersion des asphaltènes sur la combustion a été mise en évidence dans le passé par l'utilisation d'additifs dispersants et également par la combustion de fuels lourds constitués par dilution d'asphaltes précipités au pentane avec un gas-oil de cracking catalytique de raffinerie (LCO. Ce sont ces fuels que l'on a considérés dans la présente étude. L'effet de ce facteur dispersion n'a pas été quantifié jusqu'alors, la difficulté étant de définir une grandeur mesurable représentant la répartition des agglomérats d'asphaltènes. Dans cette étude, on a essayé en un premier temps de faire une approche fractale de la répartition des asphaltènes à partir de clichés (préparés par la société Total, cette méthode ayant déjà été utilisée avec succès pour décrire des structures d'aspects comparables. Malheureusement, on s'est heurté à des

  1. Compilation of the calculation elements of the electronic equipments reliability; Recueil des elements de calcul de la fiabilite des equipements electroniques

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, R.; D' Harcourt, A.; Dupuy, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    The aim of this work is to allow the practical execution of the estimated calculation of the electronic devices reliability and to standardize the source and the approach of the calculations while giving a systematic character to their execution mode. The systematic character of the calculations allows a comparison of the reliability of different materials and a rapid control of the calculations validity; at last, it brings out the use conditions of all the components of a set. A reliability calculation made according to the method described here reveals: -components badly used -the relative influence on the reliability of the set, of a component or a components group taking into account of the number, of the characteristics and of the use of these ones. At last, the results of the calculation allows to organize the exploitation (availability) and the maintenance (staff, stock of components) of the materials. The failure rates given in this book are only relating to the components service-life and do not correspond to precocious failures. (authors) [French] L'objet du present recueil est d'une part de permettre l'execution pratique du calcul previsionnel de la fiabilite des equipements electroniques et d'autre part d'uniformiser l'origine et la presentation de calculs en donnant un caractere systematique a leur mode d'execution. Le caractere systematique des calculs permet une comparaison de la fiabilite de differents materiels et un controle rapide de la validite des calculs; enfin il met en relief les conditions d'utilisation de tous les composants d'un ensemble. Un calcul de fiabilite realise selon la methode preconise par ce document permet la mise en evidence: -des composants mal utilises -de l'influence relative sur la fiabilite de l'ensemble, d'un composant ou d'un groupe de composants compte tenu du nombre, des caracteristiques et de l'utilisation de ceux-ci. Enfin, les resultats du

  2. Air pollution emission reduction techniques in combustion plants; Technique de reduction des emissions de polluants atmospheriques dans les installations de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Bouscaren, R. [CITEPA, Centre Interprofessionnel Technique d`Etudes de la Pollution Atmospherique, 75 - Paris (France)

    1996-12-31

    Separating techniques offer a large choice between various procedures for air pollution reduction in combustion plants: mechanical, electrical, filtering, hydraulic, chemical, physical, catalytic, thermal and biological processes. Many environment-friendly equipment use such separating techniques, particularly for dust cleaning and fume desulfurizing and more recently for the abatement of volatile organic pollutants or dioxins and furans. These processes are briefly described

  3. Study of the strength of the internal can for internally and externally cooled fuel elements intended for gas graphite reactors; Etude de la tenue de la gaine interne pour-element combustible a refroidissement interne et externe d'un reacteur graphite-gaz

    Energy Technology Data Exchange (ETDEWEB)

    Boudouresque, B; Courcon, P; Lestiboubois, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The cartridge of an internally and externally cooled annular fuel element used in gas-graphite reactors is made up of an uranium fuel tube, an external can and an internal can made of magnesium alloy. For the thermal exchange between the internal can and the fuel to be satisfactory, it is necessary for the can to stay in contact with the uranium under all temperature conditions. This report, based on a theoretical study, shows how the internal can fuel gap varies during the processes of canning, charging into the reactor and thermal cycling. The following parameters are considered: tube diameter, pressure of the heat carrying gas, gas entry temperature, plasticity of the can alloy. It is shown that for all operating conditions the internal can of a 77 x 95 element, planned for a gas-graphite reactor with a 40 kg/cm{sup 2} gas pressure, should remain in contact with the fuel. (authors) [French] La cartouche d'un element combustible annulaire, a refroidissement interne et externe pour reacteur graphite-gaz, est composee d'un tube combustible en uranium, d'une gaine externe et d'une gaine interne en alliage de magnesium. Pour que l'echange thermique entre la gaine interne et le combustible soit bon, il faut que la gaine reste appliquee sur l'uranium quel que soit le regime de temperature. Cette note a pour but de montrer comment, d'apres une etude theorique, le jeu combustible-gaine interne varie au cours des operations de gainage, de chargement dans le reacteur, et des cyclages thermiques. Les parametres suivants sont etudies: diametres de tube, pression du gaz caloporteur, temperature d'entree du gaz, plasticite de l'alliage de gaine. Il est montre que, quel que soit le regime de fonctionnement, la gaine interne d'un element 77 x 95, en projet pour un reacteur graphite-gaz sous pression de 40 kg/cm{sup 2}, doit rester appliquee sur le combustible. (auteurs)

  4. Mercury and Air Toxic Element Impacts of Coal Combustion By-Product Disposal and Utilizaton

    Energy Technology Data Exchange (ETDEWEB)

    David Hassett; Loreal Heebink; Debra Pflughoeft-Hassett; Tera Buckley; Erick Zacher; Mei Xin; Mae Sexauer Gustin; Rob Jung

    2007-03-31

    The University of North Dakota Energy & Environmental Research Center (EERC) conducted a multiyear study to evaluate the impact of mercury and other air toxic elements (ATEs) on the management of coal combustion by-products (CCBs). The ATEs evaluated in this project were arsenic, cadmium, chromium, lead, nickel, and selenium. The study included laboratory tasks to develop measurement techniques for mercury and ATE releases, sample characterization, and release experiments. A field task was also performed to measure mercury releases at a field site. Samples of fly ash and flue gas desulfurization (FGD) materials were collected preferentially from full-scale coal-fired power plants operating both without and with mercury control technologies in place. In some cases, samples from pilot- and bench-scale emission control tests were included in the laboratory studies. Several sets of 'paired' baseline and test fly ash and FGD materials collected during full-scale mercury emission control tests were also included in laboratory evaluations. Samples from mercury emission control tests all contained activated carbon (AC) and some also incorporated a sorbent-enhancing agent (EA). Laboratory release experiments focused on measuring releases of mercury under conditions designed to simulate CCB exposure to water, ambient-temperature air, elevated temperatures, and microbes in both wet and dry conditions. Results of laboratory evaluations indicated that: (1) Mercury and sometimes selenium are collected with AC used for mercury emission control and, therefore, present at higher concentrations than samples collected without mercury emission controls present. (2) Mercury is stable on CCBs collected from systems both without and with mercury emission controls present under most conditions tested, with the exception of vapor-phase releases of mercury exposed to elevated temperatures. (3) The presence of carbon either from added AC or from unburned coal can result in mercury

  5. Decontamination of irradiated-fuel processing waste using manganese dioxide hydrate; Decontamination des effluents de traitement des combustibles irradies par le bioxyde de manganese hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Auchapt, J M; Gaudier, J F [Commissariat a l' Energie Atomique, Chusclan (France). Centre de Production de Plutonium de Marcoule

    1969-07-01

    The 'manganese dioxide' process is designed to replace the 'calcium carbonate' treatment for low and medium activity wastes. The objective to attain during the research for a new process was the diminution of the volume of the sludge without decreasing the decontamination factor of the wastes. The new process involves addition in series of twice over 100 ppm of Mn{sup 2+} in the waste which has previously been made basic and oxidizing; the precipitate formed in situ is separated after each addition. The process has the advantage of increasing the decontamination of strontium. The treatment can be used in a plant including two decantation units and has given effective results when applied in such a plant. (author) [French] Le procede au ''bioxyde de manganese'' est destine a remplacer le traitement ''carbonate de calcium'' dans les effluents de moyenne activite. L'objectif poursuivi lors de la recherche d'un procede nouveau etait de diminuer le volume des boues sans diminuer le facteur de decontamination des effluents. Le nouveau traitement consiste a effectuer en cascade sur les effluents rendus basiques et oxydants une double precipitation de 100 ppm de Mn{sup 2+} avec separation intermediaire du precipite. Il presente en outre l'avantage d'ameliorer la decontamination en strontium. Le traitement est utilisable dans la chaine des deux decanteurs et a donne satisfaction lors de son exploitation industrielle. Le volume des boues seches a ete reduit d'un facteur 3 a 4 par rapport au traitement carbonate. (auteur)

  6. Natural gas combustion and indoor air quality in domestic premises; Combustion du gaz naturel et qualite de l'air a l'interieur des habitations

    Energy Technology Data Exchange (ETDEWEB)

    Occhio, L.; Riva, A. [Snam, (Italy); Canci, F.; Scevarolli, V. [Italgas, Torino (Italy)

    2000-07-01

    Indoor air quality depends on many factors; combustion appliances are one of the sources of emissions inside dwellings. Their installation is regulated by UNI-CIG standards which also establish the ventilation and aeration requirements needed to guarantee the safety and healthiness of the environment. In order to critically evaluate the effect on indoor air quality of using gas appliances under different operational regimes and in different types of building, Snam and Italgas have developed a research project in co-operation with Enitecnologie and Turin Polytechnic, even to provide theoretical and experimental support for standardisation activities. The results of the presented research include experimental measurements made in real buildings, mathematical modelling and analysis of Italian and international literature. The results show that use of combustion appliances has little influence on indoor air quality and does not affect people's health. (authors)

  7. Experimental and numerical study of the active control of jets inside combustion chambers; Etude experimentale et numerique du controle actif de jets dans des chambres de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Faivre, V

    2003-12-15

    Combustion instabilities occur when the flame heat release couples with the acoustic waves propagating in the combustion chamber. This phenomenon can lead to strong vibrations and noise but also, sometimes, to the complete combustion device failure. That is the reason why so many studies focus on the control of those instabilities. The method chosen in this study consists in an active control device (or set of actuators) having a strong effect on the mixing of the burner exhaust flow with the ambient fluid. The model configuration studied consists in a non reactive jet of air controlled by four small tangential secondary jets. Experiments have been carried out to optimize the control device geometry. The configuration identified as the most efficient, in terms of mixing enhancement, has been simulated through Large Eddy Simulations (LES). The objective of the numerical part of the present work is double. First, the numerical simulations provide a better understanding of the phenomena occurring when the control is on. Then, it is shown that LES can be considered as a tool to predict the effects of a control device on a flow. (author)

  8. Sinter aluminium as cladding material for fuel elements; Aluminium fritte comme materiau de gainage pour les elements combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Mann, K E; Boudouresques, M B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Otto Fuchs, Meinerzhagen, Westfalen (Germany)

    1961-07-01

    1. Survey of the production process of sinter aluminium. 2. Description of the forming processes (extrusion, forging and rolling), whereby the production of tubing for atom piles will be explained in detail. 3. Production of ribbed tubes and tubes with close tolerances of sizes. 4. The different SAP-qualities and their properties under special consideration of the properties at elevated temperatures and the creep properties. 5. Diffusion behaviour of SAP with Be, Mg, Al, U and UO{sub 2}. 6. Corrosion behaviour in CO{sub 2} atmosphere at high temperature and in water. 7. Weldability. 8. Effect of irradiation on the mechanical properties. 9. Superiority of SAP compared with normal wrought alloys of the same composition. (author) [French] 1. Apercu des processus de production de l'aluminium fritte. 2. Expose des operations de transformation (filageries, forgeage et laminage), avec explication detaillee de la fabrication de gaine pour reacteurs. 3. Fabrication de tubes canneles et de tubes avec de faibles tolerances. 4. Diverses proprietes de l'aluminium fritte SAP, notamment proprietes aux temperatures elevees et proprietes de fluage. 5. Diffusion de l'aluminium fritte SAP en presence de Be, Mg, Al, U et UO{sub 2}. 6. Resistance a la corrosion dans une atmosphere de CO{sub 2} a temperature elevee et dans l'eau. 7. Possibilites de soudage. 8. Effet de l'irradiation sur les proprietes mecaniques. 9. Superiorite de l'aluminium fritte SAP sur les alliages forges normaux de meme composition. (auteur)

  9. Behaviour, capture and inertization of some trace elements during combustion of refuse-derived char from municipal solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Vassilev, S.V.; Braekman-Danheux, C.; Laurent, P.; Thiemann, T.; Fontana, A. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Central Lab. of Mineralogy and Crystallography

    1999-08-01

    An investigation of refuse-derived char (RDC) generated by thermolysis of municipal solid waste (MSW) was undertaken to elucidate the behaviour of some toxic and potentially toxic trace elements (Cr, Cu, Mn, Ni, Pb, Sb and Zn) plus Fe during combustion of RDC. About 87% of Sb, 66% of Pb, 60% of Cu and significant parts of Fe{gt}Zn{gt}Ni{gt}Mn{gt}Cr from the RDC are volatile at 1200{degree}C, and their behaviour in the temperature interval 500-1200{degree}C is characterized. The use of sorbents (zeolite, kaolinite, montmorillonite, coals enriched in kaolinite and calcite, and lime plus portlandite) for capture, solidification and inertization of the most volatile elements during combustion of RDC is also described. Perspective sorbents and inertants for a retention of the most volatile Pb, Sb and Cu in RDC ash are kaolinite and montmorillonite or coals enriched in these minerals. In addition, when there is an effective RDC washing (dechlorination and desulphurization), the use of sorbents for capture of some metals could be reduced or even avoided. Recommendations are given for RDC utilization and improvisation of the collection, separation procedures and removal efficiency of some heavy-metal, chloride and sulphate compounds from MSW and RDC prior to their use. The results show that a long-term strategy based on detailed understanding of the source, formation, behaviour and fate of the elements and their modes of occurrence in MSW, RDC and combustion waste residues is required in order to validate a perspective waste pyrolytic processes development. 55 refs., 3 figs., 6 tabs.

  10. A Contribution to Turbulent Combustion: Premixed Flames and Material Surfaces Une contribution à la combustion turbulente : flammes prémélangées et surfaces des matériaux

    Directory of Open Access Journals (Sweden)

    Nicolleau F.

    2006-11-01

    from each other. The turbulent diffusion process is very active to create new burning zones. This diffusion process is closely related to both the intensity and the length scale of the turbulent field. That explains the dominant role of turbulence and the adaptation of the burning rate to the rotation speed in combustion engines. Additional information useful for the reader is reported in Appendices I and II. Le comportement des flammes de prémélange a été examiné par de nombreux auteurs. En fait, le problème de la combustion en milieu turbulent repose pour beaucoup sur des comparaisons d'échelles. Dans le présent article, une première étude porte sur l'évolution d'une surface matérielle (qui peut être assimilée sous certaines conditions à une surface de flamme. On utilise successivement une démarche analytique et une démarche numérique. On constate alors la rapidité d'extension de la surface et le rôle prépondérant des petites échelles ce que confirme l'étude analytique. Les risques d'extinction sont prédits en général par comparaison d'échelles. D'une simulation directe conduite sur un cas spécifique, Poinsot confirme l'idée que ce ne sont pas les structures ayant les échelles caractéristiques de la flamme qui sont les plus redoutables, mais des structures de taille quelque peu plus grande. Dans un précédent article, le rôle cumulé des gradients locaux avait été signalé. Nous donnons à ce concept une forme quantitative en utilisant le ß modèle lequel définit un taux d'occupation de l'espace en fonction du rang (et donc de la dimension de structures. Un calcul de gradient cumulé redonne la prédiction de Poinsot. Enfin, le même ß modèle est utilisé pour définir une nouvelle zone dans la région de combustion distribuée. Des balles fluides brûlent isolément tandis qu'un processus de diffusion lié très étroitement au champ turbulent et à son intensité crée d'autres points d'allumage. Le mécanisme explique l

  11. Gas-flow detector for uranium contamination on finned-can surface of a reactor fuel; Detecteur a courant gazeux pour deceler la contamination en uranium des nervures des gaines de combustible nucleaire; Gazopotochnyj detektor zagryazneniya uranom rebristoj poverkhnosti obolochki reaktornykh teplovydelyayushchikh ehlementov; Detector de flujo gaseoso para medir la contaminacion de uranio en la superficie de la vaina de aletas de los elementos combustibles para reactores

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, H; Shiojiri, T; Maeda, Y [Kobe Kogyo Corporation, Okubo, Akashi, Hyogo (Japan)

    1962-04-15

    Calder Hall-type reactor-fuel and all JRR-3 fuels are to be inspected by this counter. (author) [French] Le detecteur a courant gazeux presente par les auteurs est un compteur proportionnel a grille, specialement concu pour deceler la contamination en uranium des nervures des gaines de combustible nucleaire. Un compteur proportionnel classique, compose seulement d'une cathode et d'un collecteur, n'est guere capable de deceler les particules alpha emises par l'uranium contaminant une surface rugueuse telle que les nervures d'une gaine de combustible nucleaire, par suite du manque d'uniformite du champ electrique pres de la surface. C'est pourquoi les auteurs ont construit un compteur proportionnel a grille. Cet appareil, de forme cylindrique, comprend le combustible, une grille, des collecteurs et une cathode, tous les elements etant disposes suivant le meme axe. Le combustible est place au centre de la grille a laquelle on applique une tension negative. L'espace entre le combustible et la grille sert de collecteur d'ions. La grille, faite de fils paralleles minces en tungstene, disposes suivant un cylindre autour du combustible, est reliee a la terre. Les collecteurs sont constitues de 16 minces fils de tungstene disposes de la meme maniere que la grille, mais chaque fil est isole electriquement des autres. Tous les collecteurs sont interconnectes par des resistances de 5 x 10{sup 4} ohms et relies au positif de la haute tension par une resistance. L'espace entre la grille, les collecteurs et la cathode sert a la multiplication du gaz, tout comme dans un compteur proportionnel classique. Chaque resistance de 5 x 10{sup 4} ohms isole la capacite parasite de chaque collecteur. La sortie du detecteur est couplee a un amplificateur a faible impedance d'entree. La faible impedance d'entree diminue aussi l'influence facheuse de la capacite parasite du circuit d'entree. Il en resulte un rapport favorable signal/bruit de fond, ce qui permet une bonne detection des particules

  12. Online elemental analysis of process gases with ICP-OES: A case study on waste wood combustion

    International Nuclear Information System (INIS)

    Wellinger, Marco; Wochele, Joerg; Biollaz, Serge M.A.; Ludwig, Christian

    2012-01-01

    Highlights: ► Simultaneous measurements of 23 elements in process gases of a waste wood combustor. ► Mobile ICP spectrometer allows measurements of high quality at industrial plants. ► Continuous online measurements with high temporal resolution. ► Linear correlations among element concentrations in the raw flue gas were detected. ► Novel sampling and calibration methods for ICP-OES analysis of process gases. - Abstract: A mobile sampling and measurement system for the analysis of gaseous and liquid samples in the field was developed. An inductively coupled plasma optical emission spectrometer (ICP-OES), which is built into a van, was used as detector. The analytical system was calibrated with liquid and/or gaseous standards. It was shown that identical mass flows of either gaseous or liquid standards resulted in identical ICP-OES signal intensities. In a field measurement campaign trace and minor elements in the raw flue gas of a waste wood combustor were monitored. Sampling was performed with a highly transport efficient liquid quench system, which allowed to observe temporal variations in the elemental process gas composition. After a change in feedstock an immediate change of the element concentrations in the flue gas was detected. A comparison of the average element concentrations during the combustion of the two feedstocks showed a high reproducibility for matrix elements that are expected to be present in similar concentrations. On the other hand elements that showed strong differences in their concentration in the feedstock were also represented by a higher concentration in the flue gas. Following the temporal variations of different elements revealed strong correlations between a number of elements, such as chlorine with sodium, potassium and zinc, as well as arsenic with lead, and calcium with strontium.

  13. Microwave-induced combustion of crude oil for further rare earth elements determination by USN–ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, J.S.F. [Departamento de Química Inorgânica, Universidade Federal do Rio Grande do Sul, 97105-900 Porto Alegre, RS (Brazil); Pereira, L.S.F.; Mello, P.A. [Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Guimarães, R.C.L.; Guarnieri, R.A.; Fonseca, T.C.O. [CENPES/PETROBRAS, 21941-945 Rio de Janeiro, RJ (Brazil); Flores, E.M.M., E-mail: ericommf@gmail.com [Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil)

    2014-09-24

    Highlights: • Microwave-induced combustion was applied for light and heavy crude oils digestion. • It was feasible to determine all the REEs in heavy crude oil by ICP-MS. • Only diluted acid solutions were used in agreement to green chemistry recommendations. - Abstract: A procedure for light and heavy crude oils digestion by microwave-induced combustion (MIC) is proposed for the first time for further rare earth elements (REE) determination by inductively coupled plasma mass spectrometry (ICP-MS) equipped with an ultrasonic nebulizer (USN). Samples of crude oil (API density of 10.8–23.5, up to 250 mg) were inserted in polycarbonate capsules and combusted using 20 bar of oxygen and 50 μL of 6 mol L{sup −1} ammonium nitrate as igniter. Nitric acid solutions (1–14.4 mol L{sup −1}) were evaluated for analyte absorption and a reflux step was applied after combustion (5 min of microwave irradiation at 1400 W) in order to achieve better analyte recoveries. Accuracy was evaluated using a spiked sample and also by comparison of results obtained by microwave-assisted digestion combined to ultraviolet radiation (MW–UV) and by neutron activation analysis (NAA). Using 3 mol L{sup −1} HNO{sub 3}, quantitative recoveries (better than 97%) were obtained for all analytes. Blank values were always negligible. Agreement was higher than 96% for La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y by comparison of results with those obtained by MW–UV and by NAA (only for La, Ce, Nd, Sm, and Yb). Residual carbon content in digests using MIC was always below 1%. As an advantage over conventional procedures for crude oil digestion, using MIC, it was possible to use diluted acid as absorbing solution, obtaining better limits of detection and avoiding interferences in REE determination by USN–ICP-MS.

  14. Contribution to the study of nuclear fuel materials with a metallic uranium base; Contribution a l'etude des materiaux combustibles nucleaires a base d'uranium metallique

    Energy Technology Data Exchange (ETDEWEB)

    Englander, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-11-15

    In a power reactor destined to supply industrially recoverable thermal energy, the most economical source of heat still consists of natural metallic uranium. However, the nuclear fuel material, most often employed in the form of rods of 20 to 40 mm diameter, is subjected to a series of stresses which lead to irreversible distortions usually incompatible with the substructure of the reactor. As a result the fuel material must possess at the outset a certain number of qualities which must be determined. Investigations have therefore been carried out, first on the technological characters peculiar to each of the three allotropic phases of pure uranium metal, and on their interactions on the stabilisation of the material which consists of either cast uranium or uranium pile-treated in the {gamma} phase. (author) [French] Dans un reacteur de puissance destine a fournir de l'energie thermique industriellement recuperable, la source de chaleur la plus economique reste constituee par de l'uranium metallique naturel. Or, le materiau combustible nucleaire, employe le plus souvent sous forme de barreaux de 20 a 40 mm de diametre, se trouve soumis a un ensemble de contraintes qui provoque des deformations irreversibles, le plus souvent incompatibles avec l'infrastructure du reacteur. Par consequent, le materiau combustible doit presenter a l'origine un certain nombre de qualites qu'il est necessaire de determiner. Aussi a-t-on d'abord etudie les caracteres technologiques propres a chacune des trois phases allotropiques de l'uranium-metal pur et leurs interactions sur la stabilisation du materiau constitue soit par de l'uranium coule, soit par de l'uranium traite en pile en phase {gamma}. (auteur)

  15. Some physics aspects of cermet and ceramic fast systems; Quelques aspects de la physique des reacteurs a neutrons rapides utilisant des cermets et des ceramiques comme combustibles; Nekotorye fizicheskie aspekty kermetnykh i keramicheskikh sistem na bystrykh nejtronakh; Algunos aspectos fisicos de los sistemas rapidos a base de combustibles cermet y ceramicos

    Energy Technology Data Exchange (ETDEWEB)

    Codd, J; James, M F; Mann, J E [United Kingdom Atomic Energy Authority, Reactor Group (United Kingdom)

    1962-03-15

    The characteristics of a system using an iron-based oxide cermet as fuel material are discussed. A transport theory investigation to develop methods of predicting the effect of core heterogeneity on reactivity and flux distribution is described. Some preliminary calculations are also given of resonance self-shielding and Doppler temperature effects in a cermet system. (author) [French] Les auteurs etudient les caracteristique s d'un reacteur utilisant comme combustible un cermet d'oxydes a armature de fer. Ils exposent une application de la theorie du transport a la mise au point des methodes permettant de prevoir l'effet de l'heterogeneite du coeur sur la reactivite et sur la distribution du flux. Ils donnent egalement quelques calculs preliminaires d'effets d'autoprotection due a la resonance et d'effet Doppler du a la chaleur dans un reacteur utilisant un cermet. (author) [Spanish] La memoria discute las caracteristicas de un sistema que emplea como combustible un oxido tipo cermet a base de hierro. Describe una investigacion de la teoria de transporte con miras a desarrollar metodos para evaluar el efecto de la heterogeneidad del cuerpo sobre la reactividad y la distribucion de flujo. Tambien da algunos calculos preliminares de los efectos del autoblindaje por resonancia y de la temperatura de Doppler en un sistema de tipo cermet. (author) [Russian] Obsuzhdayutsya kharakteristiki sistemy, ispol'zuyushchej v kachestve toplivnogo materiala oksidnye kermety, razrabotannye na osnove zheleza. Opisyvaetsya issledovanie teorii perenosa, chtoby razvit' metody predskazaniya vliyaniya geterogennosti aktivnoj zony na reaktivnost' i raspredelenie potoka. Dayutsya takzhe nekotorye predvaritel'nye raschety ehffektov rezonansnoj samozashchity i temperaturnogo ehffekta Dopplera v kermetnoj sisteme. (author)

  16. Combustion gas cleaning in the ceramic tile industry: technical guide; Nettoyage des fumees de combustion dans l'industrie ceramique: guide technique

    Energy Technology Data Exchange (ETDEWEB)

    Lezaun, F.J. [ENAGAS-Grupo Gas Natural (Spain); Mallol, G.; Monfort, E. [instituto de Tecnologia Ceramica, ITC (Spain); Busani, G. [Agenzia Regionale per la Prevenzione e l' Amiente, ARPA (Spain)

    2000-07-01

    This document presents a summary of a technical guide drawn up on combustion gas cleaning systems in ceramic frit and tile production. The guide describes the method to be followed for selecting the best possible solutions for reducing pollutant concentrations in different emission sources, in accordance with current regulatory requirements and the CET recommendation. There are three sources of combustion gas air emissions that need to be cleaned in ceramic tile and frit production and they are usually related to the following process stages: slip spray drying, tile firing and frit melting. The different nature of the emissions means that different substances will need to be cleaned in each emission. Thus, in spray drying and frit melting, the only species to be cleaned are suspended particles, while in tile firing, it is also necessary to reduce the fluorine concentration. The systems analysed in this guide are mainly wet cleaning systems, bag filters and electrostatic precipitators. In the study, the efficiency of these cleaning systems is compared at each emission source from a technical and economic point of view, and concrete solutions are put forward in each case, together with a list of suppliers of the technologies involved. (authors)

  17. Determination of nonmetallic elements in actinide complexes by oxygen flask combustion (OFC) (Part 2). Sulphur

    International Nuclear Information System (INIS)

    Ruikar, P.B.; Nagar, M.S.; Subramanian, M.S.

    1989-01-01

    This report describes the determination of sulphur in metallic complexes by oxygen flask combustion followed by conductivity titration with standard barium acetate solution in alcoholic medium and lead electrode titration using a lead ion sensitive electrode. Various organic ligands and uranyl and plutonyl synergistic complexes have been analysed by both these methods and the precision and accuracy of the results have been found to be satisfactory. (author). 12 refs., 12 tabs

  18. Release of Fission Products from UC-ZrC Fuel Inserts; Degagement des produits de fission liberes dans des noyaux combustibles UC-ZrC; Vydelenie produktov deleniya iz topliv UC - ZrC; Liberacion de productos de fision por pastillas de combustible de UC-ZrC

    Energy Technology Data Exchange (ETDEWEB)

    Barth, F.; Von der Decken, C. B.; Schifferstein, K. [Brown Boveri/Krupp Reaktorbau G.M.B.H., Duesseldorf (Germany); Clauss, A.; Reichel, H.; Rygaert, J.; Ruston, W. R. [Societe d' Etudes de Recherches et d' Applications pour l' Industrie (S.E.R.A.I.), Brussels (Belgium)

    1963-11-15

    energies obtained from different types of pellets, although the values of D/r{sub 0}{sup 2} sometimes differed by four orders of magnitude at the same sample temperatures. After irradiation, the activities of the isotopes I{sup 131}, Sr{sup 85}, Ba{sup 140} and Ce{sup 141} were determined in the graphite of the capsules. Except for I{sup 131}, the activities were higher than those expected for a release by recoil only. The values for Sr{sup 89}, Ba{sup 140} and Ce{sup 141} are too high to be a result of a diffusion of their corresponding rare gas precursors. It is assumed that the measured isotopes or their non-rare gas precursors were released by diffusion. (author) [French] Les auteurs ont etudie sous irradiation, dans une boucle, le degagement des produits de fission liberes par des pastilles dont la composition approximative etait UC + 20 ZrC. Il s'agissait de verifier la possibilite d'utiliser ces pastilles comme noyaux d'elements combustibles spheriques pour le reacteur a haute temperature actuellement construit a Juliers par la societe Brown-Boveri/Krupp Reaktorbau GmbH. Les essais ont ete faits sur des pastilles encapsulees dans du graphite et sur des pastilles non encapsulees. La surface de certaines pastilles etait constituee par une couche de carbure de zirconium pur d'une epaisseur de 1 a 2 mm. Les echantillons ent ete places dans des fours electriques a resistance pouvant atteindre une temperature de 1600{sup o}C. Pendant l'irradiation, les flux de neutrons etaient de 3 a 4 x 10{sup 10}n/cm{sup 2}s. La boucle permettait de mesurer, pendant l'irradiation, le degagement de {sup 85m}Kr, {sup 87}Kr, {sup 88}Kr, {sup 133}Xe et {sup 135}Xe et de determiner indirectement les quantites de {sup 133}I et {sup 135}I, apres l'arret du reacteur. Le degagement minimum de {sup 131}I, {sup 89}Sr, {sup 140}Ba et {sup 141}Ce a ete determine radiochimiquement apres retrait des echantillons. Il a ete egalement possible de mesurer la fraction de recul {epsilon}{sub R} seule, le

  19. Study of new technique of solid combustible materials to determination of volatile elements by flame atomic absorption spectrophotometry

    International Nuclear Information System (INIS)

    Campos, R.C. de.

    1988-01-01

    A new technique for direct trace element analysis of solid combustible materials is described. The samples (up to 10 mg) are weighed on a graphite platform wich is then placed in a quartz tube, at the focal point of three infrared lamps. When the lamps are turned on, the sample burns in a stream of air, and the resulting dry aerosol containing volatile elements such as Hg, Cd, Bi, Tl, Zn, Pb and Cu is carried into the mixing chamber and thence into the flame, where the atomic absorption measurement is carried out. This technique overcomes chemical sample preparation steps, avoiding contaminations of losses associated with these steps. A ''furnace in flame'' system where the aerosol is transported to a flame heated T-tube is also described. The influence of flame stoichiometry, observation height, platform material and air flux intensity was studied inorder to determine optimal analytical conditions. (author) [pt

  20. Partitioning behaviour of trace elements in a stoker-fired combustion unit : An example using bituminous coals from the Greymouth coalfield (Cretaceous), New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.; Moore, T.A.; Weaver, S.D. [University of Canterbury, Department of Geological Science, Christchurch (New Zealand); Clemens, A.H.; Gong, D. [CRL Energy Ltd, PO Box 31 244, Lower Hutt (New Zealand); Eby, N. [Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, Lowell, MA 01854 (United States)

    2005-07-20

    In order to understand trace element behaviour during combustion of coals from the Greymouth coalfield, combustion tests were performed on three seam composite samples. The major and trace elements from sub-samples of feed coal, bottom ash, fly ash, and flue gas were analysed by different techniques including inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), wavelength dispersive X-ray fluorescence (WD-XRF), and scanning electron microscopy with energy-dispersive X-ray analyser (SEM-EDXA). To help better understand trace element partitioning in combustion ash, float-sink and sequential leaching experiments were also employed to determine the association of trace elements with mineral matter or organic matter. Instrumental Neutron Activation Analysis (INAA) was also employed to determine trace element content in float and sink fractions of fly ash as well as in three major phases in the bottom ash. The partitioning behaviour of trace elements, including some that are environmentally sensitive, was also investigated through the use of float-sink tests and direct determination of trace elements in different combustion ash types and phases. Mass balance and partitioning of major and trace elements have been studied to determine the fate of trace elements after combustion. The partitioning of trace elements, especially hazardous air pollutants (HAPs), in different combustion ashes can be summarised as follows:1.Most trace elements, especially As, Ba, Co, Cr, Mn, Ni, are partitioned in the glassy and refractory bottom ash fractions. 2.A significant proportion of trace elements of As, Se, and Pb are partitioned into fly ash fractions. 3.Some volatile elements (e.g. > 90% of S and Hg and up to 64% of Cl) and, to a lesser extent, B (up to 44%) and Cd (up to 50%) are partitioned in the flue gas fraction. 4.Although the low ash yield of Greymouth coal seams have the advantage of generating less solid

  1. Pollution active control: a strategy for a clean and efficient combustion; Le controle actif des polluants: une strategie pour une combustion propre et efficace

    Energy Technology Data Exchange (ETDEWEB)

    Lacas, F. [CNRS Ecole Centrale de Paris, 75 (France). Laboratoire E.M2.C

    1996-12-31

    The active control NOx reduction concept has been applied on two burners (20 kW and 840 kW), using a rotary valve enabling an excitation in the 100 to 1000 Hz band, that can be mounted on existing appliances such as domestic or industrial boilers. NOx level reduction may reach 15 pc for the 20 kW burner, 25 pc for the 840 kW burner with domestic fuel oil and 35 pc for the 840 kW burner using pyridine doped domestic fuel oil. Mechanisms are detailed through flow visualization, and consist mainly in an annular vortex inducing a fuel/air pre-mixing favourable to a large decrease in NOx generation level and establishing a staged process such as in re-burning processes. The pulsed combustion process may be also combined to other pollution control systems

  2. Construction and validation of detailed kinetic models for the combustion of gasoline surrogates; Construction et validation de modeles cinetiques detailles pour la combustion de melanges modeles des essences

    Energy Technology Data Exchange (ETDEWEB)

    Touchard, S.

    2005-10-15

    The irreversible reduction of oil resources, the CO{sub 2} emission control and the application of increasingly strict standards of pollutants emission lead the worldwide researchers to work to reduce the pollutants formation and to improve the engine yields, especially by using homogenous charge combustion of lean mixtures. The numerical simulation of fuel blends oxidation is an essential tool to study the influence of fuel formulation and motor conditions on auto-ignition and on pollutants emissions. The automatic generation helps to obtain detailed kinetic models, especially at low temperature, where the number of reactions quickly exceeds thousand. The main purpose of this study is the generation and the validation of detailed kinetic models for the oxidation of gasoline blends using the EXGAS software. This work has implied an improvement of computation rules for thermodynamic and kinetic data, those were validated by numerical simulation using CHEMKIN II softwares. A large part of this work has concerned the understanding of the low temperature oxidation chemistry of the C5 and larger alkenes. Low and high temperature mechanisms were proposed and validated for 1 pentene, 1-hexene, the binary mixtures containing 1 hexene/iso octane, 1 hexene/toluene, iso octane/toluene and the ternary mixture of 1 hexene/toluene/iso octane. Simulations were also done for propene, 1-butene and iso-octane with former models including the modifications proposed in this PhD work. If the generated models allowed us to simulate with a good agreement the auto-ignition delays of the studied molecules and blends, some uncertainties still remains for some reaction paths leading to the formation of cyclic products in the case of alkenes oxidation at low temperature. It would be also interesting to carry on this work for combustion models of gasoline blends at low temperature. (author)

  3. Effect of Ash on Oxygen Carriers for the Application of Chemical Looping Combustion to a High Carbon Char Effet des cendres sur l’activité des porteurs d’oxygène dans la combustion du charbon en boucle chimique

    Directory of Open Access Journals (Sweden)

    Rubel A.

    2011-02-01

    activity of the OCs and both OCs performed well. The results were promising for the application of CLC directly to solid fuels. L’application de la combustion en boucle chimique (CLC aux combustibles solides est actuellement étudiée à l’Université du Kentucky, au Centre de Recherche de l’Energie Appliquée (CAER dans le but de développer un procédé de gazéification/combustion en boucle chimique pressurisé (PCLC/G afin de générer de l’électricité à partir de charbon. Un des principaux aspects de la combustion en boucle chimique de combustibles solides est la compréhension de l’effet des cendres sur la réactivité des porteurs d’oxygène (OCs. L’effet des cendres sur la capacité de transfert d’oxygène et sur l’aptitude à oxyder le charbon est étudié avec deux porteurs d’oxygène à base d’oxydes de fer. Les cendres utilisées sont des cendres volantes provenant d’une centrale thermique au charbon. Les expériences sont réalisées dans un système composé d’une thermo-balance couplée à un spectrographe de masse (TGMS dans lequel on utilise d’abord 500 mg d’un mélange de cendres/porteurs d’oxygène à différentes concentrations de cendres allant jusqu’à 75 %. Le gaz réducteur est composé de 10 % de H2, 15 % de CO, 20 % de CO2 et de 55 % de Ar; et le gaz oxydant est composé de 20 % de O2 dans Ar. Les réactions d’oxydation/réduction sont quasi totales. D’après ces expériences, les cendres ont une activité propre de porteur d’oxygène, liée à la présence de fer dans les cendres, confirmée par les analyses DRX. Cela génère une augmentation du gain ou de la perte de masse du mélange pendant l’oxydation/réduction. Les vitesses d’oxydation/réduction augmentent avec la concentration des cendres à cause de l’augmentation de la porosité du mélange de porteurs d’oxygène avec les cendres, ce qui permet un meilleur accès des gaz réactifs sur les sites actifs des porteurs d’oxygène. Dans un

  4. Contribution to the analysis of light elements using x fluorescence excited by radio-elements; Contribution a l'analyse des elements legers par fluorescence x excitee au moyen de radioelements

    Energy Technology Data Exchange (ETDEWEB)

    Robert, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    In order to study the possibilities of using radioactive sources for the X-fluorescence analysis of light elements, the principle is given, after a brief description of X-fluorescence, of the excitation of this phenomenon by X, {beta} and {alpha} emission from radio-elements. The operation and use of the proportional gas counter for X-ray detection is described. A device has been studied for analysing the elements of the 2. and 3. periods of the Mendeleev table. It makes it possible to excite the fluorescence with a radioactive source emitting X-rays or a particles; the X-ray fluorescence penetrates into a window-less proportional counter, this being made possible by the use of an auxiliary electric field in the neighbourhood of the sample. The gas detection pressure leading to the maximum detection yield is given. The spectra are given for the K{sub {alpha}} lines of 3. period elements excited by {sup 55}Fe, {sup 3}H/Zr and {sup 210}Po sources; for the 2. period the K{sub {alpha}} spectra of carbon and of fluorine excited by the {alpha} particles of {sup 210}Po. (author) [French] Afin d'etudier les possibilites d'emploi de sources radioactives a l'analyse par fluorescence X des elements legers, on presente apres rappel de notions generales sur la fluorescence X, le principe de l'excitation de ce phenomene par emission X, {beta}, {alpha} de radioelements. Le fonctionnement et l'utilisation du compteur proportionnel a gaz a la detection du rayonnement X est developpe. Un dispositif permettant l'analyse des elements des 2eme et 3eme periodes de la classification de Mendeleev est etudie. Il permet l'excitation de la fluorescence par source radioactive emettrice de rayons X ou de particules {alpha}; le rayonnement X de fluorescence penetre dans un compteur proportionnel depourvu de fenetre, ceci est rendu possible en creant un champ electrique auxiliaire au voisinage de l'echantillon. On definit une pression du gaz de detection pour un rendement de detection maximal

  5. Contribution to the analysis of light elements using x fluorescence excited by radio-elements; Contribution a l'analyse des elements legers par fluorescence x excitee au moyen de radioelements

    Energy Technology Data Exchange (ETDEWEB)

    Robert, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    In order to study the possibilities of using radioactive sources for the X-fluorescence analysis of light elements, the principle is given, after a brief description of X-fluorescence, of the excitation of this phenomenon by X, {beta} and {alpha} emission from radio-elements. The operation and use of the proportional gas counter for X-ray detection is described. A device has been studied for analysing the elements of the 2. and 3. periods of the Mendeleev table. It makes it possible to excite the fluorescence with a radioactive source emitting X-rays or a particles; the X-ray fluorescence penetrates into a window-less proportional counter, this being made possible by the use of an auxiliary electric field in the neighbourhood of the sample. The gas detection pressure leading to the maximum detection yield is given. The spectra are given for the K{sub {alpha}} lines of 3. period elements excited by {sup 55}Fe, {sup 3}H/Zr and {sup 210}Po sources; for the 2. period the K{sub {alpha}} spectra of carbon and of fluorine excited by the {alpha} particles of {sup 210}Po. (author) [French] Afin d'etudier les possibilites d'emploi de sources radioactives a l'analyse par fluorescence X des elements legers, on presente apres rappel de notions generales sur la fluorescence X, le principe de l'excitation de ce phenomene par emission X, {beta}, {alpha} de radioelements. Le fonctionnement et l'utilisation du compteur proportionnel a gaz a la detection du rayonnement X est developpe. Un dispositif permettant l'analyse des elements des 2eme et 3eme periodes de la classification de Mendeleev est etudie. Il permet l'excitation de la fluorescence par source radioactive emettrice de rayons X ou de particules {alpha}; le rayonnement X de fluorescence penetre dans un compteur proportionnel depourvu de fenetre, ceci est rendu possible en creant un champ electrique auxiliaire au voisinage de l'echantillon. On definit une pression du gaz de detection

  6. Radiative transfer modelling in combusting systems using discrete ordinates method on three-dimensional unstructured grids; Modelisation des transferts radiatifs en combustion par methode aux ordonnees discretes sur des maillages non structures tridimensionnels

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, D.

    2004-04-01

    The prediction of pollutant species such as soots and NO{sub x} emissions and lifetime of the walls in a combustion chamber is strongly dependant on heat transfer by radiation at high temperatures. This work deals with the development of a code based on the Discrete Ordinates Method (DOM) aiming at providing radiative source terms and wall fluxes with a good compromise between cpu time and accuracy. Radiative heat transfers are calculated using the unstructured grids defined by the Computational Fluid Dynamics (CFD) codes. The spectral properties of the combustion gases are taken into account by a statistical narrow bands correlated-k model (SNB-ck). Various types of angular quadrature are tested and three different spatial differencing schemes were integrated and compared. The validation tests show the limit at strong optical thicknesses of the finite volume approximation used the Discrete Ordinates Method. The first calculations performed on LES solutions are presented, it provides instantaneous radiative source terms and wall heat fluxes. Those results represent a first step towards radiation/combustion coupling. (author)

  7. An Experimental Investigation of Self-Excited Combustion Dynamics in a Single Element Lean Direct Injection (LDI) Combustor

    Science.gov (United States)

    Gejji, Rohan M.

    OH distribution in the combustion zone. The DMD analysis was able to identify similar dominant unstable modes in the combustor. Recommendations for future work are based on the continued requirement for quantitative and spatio-temporally resolved data for direct comparison with computational efforts to develop predictive capabilities for combustion instabilities at relevant operating conditions. Discriminating instability behavior for the prototypical combustor demonstrated in this study is critical for any robust validation effort Unit physics based scaling of the current effort to multi-element combustors along with improvement in diagnostic techniques and analysis efforts are recommended for advancement in understanding of the complex physics in the multi-phase, three dimensional and turbulent combustion processes in the LDI combustor.

  8. Hot-Fire Test Results of an Oxygen/RP-2 Multi-Element Oxidizer-Rich Staged-Combustion Integrated Test Article

    Science.gov (United States)

    Hulka, J. R.; Protz, C. S.; Garcia, C. P.; Casiano, M. J.; Parton, J. A.

    2016-01-01

    As part of the Combustion Stability Tool Development project funded by the Air Force Space and Missile Systems Center, the NASA Marshall Space Flight Center was contracted to assemble and hot-fire test a multi-element integrated test article demonstrating combustion characteristics of an oxygen/hydrocarbon propellant oxidizer-rich staged-combustion engine thrust chamber. Such a test article simulates flow through the main injectors of oxygen/kerosene oxidizer-rich staged combustion engines such as the Russian RD-180 or NK-33 engines, or future U.S.-built engine systems such as the Aerojet-Rocketdyne AR-1 engine or the Hydrocarbon Boost program demonstration engine. For the thrust chamber assembly of the test article, several configurations of new main injectors, using relatively conventional gas-centered swirl coaxial injector elements, were designed and fabricated. The design and fabrication of these main injectors are described in a companion paper at this JANNAF meeting. New ablative combustion chambers were fabricated based on hardware previously used at NASA for testing at similar size and pressure. An existing oxygen/RP-1 oxidizer-rich subscale preburner injector from a previous NASA-funded program, along with existing and new inter-connecting hot gas duct hardware, were used to supply the oxidizer-rich combustion products to the oxidizer circuit of the main injector of the thrust chamber. Results from independent hot-fire tests of the preburner injector in a combustion chamber with a sonic throat are described in companion papers at this JANNAF conference. The resulting integrated test article - which includes the preburner, inter-connecting hot gas duct, main injector, and ablative combustion chamber - was assembled at Test Stand 116 at the East Test Area of the NASA Marshall Space Flight Center. The test article was well instrumented with static and dynamic pressure, temperature, and acceleration sensors to allow the collected data to be used for

  9. Sampling procedure in a willow plantation for chemical elements important for biomass combustion quality

    DEFF Research Database (Denmark)

    Liu, Na; Nielsen, Henrik Kofoed; Jørgensen, Uffe

    2015-01-01

    clone ‘Tordis’, and to reveal the relationship between sampling position, shoot diameters, and distribution of elements. Five Tordis willow shoots were cut into 10–50 cm sections from base to top. The ash content and concentration of twelve elements (Al, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, P, Si, and Zn......Willow (Salix spp.) is expected to contribute significantly to the woody bioenergy system in the future, so more information on how to sample the quality of the willow biomass is needed. The objectives of this study were to investigate the spatial variation of elements within shoots of a willow......) in each section were determined. The results showed large spatial variation in the distribution of most elements along the length of the willow shoots. Concentrations of elements in 2-year old shoots of the willow clone Tordis were fairly stable within the range of 100–285 cm above ground and resembled...

  10. 3-D modeling of parietal liquid films in internal combustion engines; Modelisation tridimensionnelle des films liquides parietaux dans les moteurs a combustion interne

    Energy Technology Data Exchange (ETDEWEB)

    Foucart, H

    1998-12-11

    To simulate the air-fuel mixing in the intake ports and cylinder of an internal combustion engines, a wall fuel liquid film model has been developed for integration in 3D CFD codes. Phenomena taken into account include wall film formation by an impinging spray without splashing effect, film transport such as governed by mass and momentum equations with hot wall effects, and evaporation considering energy equation with an analytical mass transfer formulation developed here. A continuous-fluid method is used to describe the wall film over a three dimensional complex surface. The basic approximation is that of a laminar incompressible boundary layer; the liquid film equations are written in an integral form and solved by a first-order ALE finite volume scheme; the equation system is closed without coefficient fitting requirements. The model has been implemented in a Multi-Block version of KIVA-II (KMB) and tested against problems having theoretical solutions. Then in a first step, it has been compared to the measurements obtained in a cylindrical pipe reproducing the main characteristics of SI engine intake pipe flow and in a second step, it has been compared to the Xiong experiment concerning the film evaporation on a hot wall. The film behaviour is satisfactory reproduced by the computations for a set of operating conditions. Finally, engine calculations were conducted showing the importance of including a liquid film model for the simulations. (author) 54 refs.

  11. Testing on air cleaning systems: Testing of the components in-place tests; Controle des installations d'epuration de l'air essais de conformite des elements: Tests in situ

    Energy Technology Data Exchange (ETDEWEB)

    Billard, F; Brion, J [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-07-01

    The reliability of air cleaning systems is dependent on testing they are submitted to. Although in-place tests are the most important as they act as final tests upon achieved plants, component tests are necessary too. They allow detection of defective units before they are installed, partition of unit defects from mounting defects and they are more sensitive. For similar reasons, material teats are most useful. The various tests are described, about aerosol filters for one part, iodine trap for the other. The checked features are: materials nature, units sizes, efficiency, air resistance, flammability, humidity resistance, temperature resistance, adsorbent friability, etc... On iodine trapping systems, small check traps, working by-pass with the main trap are periodically subjected to efficiency test. This control allow to cut down the in-place tests frequency, particularly when poisoning from organic vapours is to be feared. (authors) [French] La surete de fonctionnement des installations d'epuratition de l'air esf fonction des controles auxquels ces installations sont soumises. Si les tests in situ sont les plus importants puisqu'ils constituent le controle final de l'installation terminee, les essais de conformite des elements constitutifs sont egalement necessaires. Ils permettent l'elimination d'elements defectueux avant leur mise en place, la discrimination des defauts du montage de ceux de l'element et sont en outre plus sensibles. De meme, le controle des materiaux constitutifs de l'element s'avere fort utile. On decrit les differents controles, d'une part, pour les fittres a aerosols, d'autre part, pour les pieges a iode. Les caracteristiques verifiees sont: nature des materiaux, dimenesions des elements, efficacite, perte de charge, resistance mecanique, inflammabilite, tenue a l'humidite, tenue a la temperature, resistance au detassement des pieges a iode, friabilite du materiau adsorbant, etc... En ce qui concerne les installations de piegeage d

  12. Adsorption of elemental mercury vapors from synthetic exhaust combustion gas onto HGR carbon.

    Science.gov (United States)

    Musmarra, D; Karatza, D; Lancia, A; Prisciandaro, M; Mazziotti di Celso, G

    2016-07-01

    An activated carbon commercially available named HGR, produced by Calgon-Carbon Group, was used to adsorbe metallic mercury. The work is part of a wider research activity by the same group focused on the removal of metallic and divalent mercury from combustion flue gas. With respect to previously published papers, this one is aimed at studying in depth thermodynamic equilibria of metallic mercury adsorption onto a commercial activated carbon. The innovativeness lies in the wider operative conditions explored (temperature and mercury concentrations) and in the evaluation of kinetic and thermodynamic data for a commercially available adsorbing material. In detail, experimental runs were carried out on a laboratory-scale plant, in which Hg° vapors were supplied in a nitrogen gas stream at different temperature and mercury concentration. The gas phase was flowed through a fixed bed of adsorbent material. Adsorbate loading curves for different Hg° concentrations together with adsorption isotherms were achieved as a function of temperature (120, 150, 200°C) and Hg° concentrations (1.0-7.0 mg/m(3)). Experimental runs demonstrated satisfying results of the adsorption process, while Langmuir parameters were evaluated with gas-solid equilibrium data. Especially, they confirmed that adsorption capacity is a favored process in case of lower temperature and they showed that the adsorption heat was -20 kJ/mol. Furthermore, a numerical integration of differential equations that model the adsorption process was proposed. Scanning electron microscopy (SEM) investigation was an useful tool to investigate about fresh and saturated carbon areas. The comparison between them allowed identification of surface sites where mercury is adsorbed; these spots correspond to carbon areas where sulfur concentration is greater. Mercury compounds can cause severe harm to human health and to the ecosystem. There are a lot of sources that emit mercury species to the atmosphere; the main ones are

  13. Discontinuous finite element and characteristics methods for neutrons transport equation solution in heterogeneous grids; Resolution de l'equation du transport des neutrons par les methodes des elements finis discontinus et des caracteristiques structurees appliquees a des maillages heterogenes

    Energy Technology Data Exchange (ETDEWEB)

    Masiello, E

    2006-07-01

    The principal goal of this manuscript is devoted to the investigation of a new type of heterogeneous mesh adapted to the shape of the fuel pins (fuel-clad-moderator). The new heterogeneous mesh guarantees the spatial modelling of the pin-cell with a minimum of regions. Two methods are investigated for the spatial discretization of the transport equation: the discontinuous finite element method and the method of characteristics for structured cells. These methods together with the new representation of the pin-cell result in an appreciable reduction of calculation points. They allow an exact modelling of the fuel pin-cell without spatial homogenization. A new synthetic acceleration technique based on an angular multigrid is also presented for the speed up of the inner iterations. These methods are good candidates for transport calculations for a nuclear reactor core. A second objective of this work is the application of method of characteristics for non-structured geometries to the study of double heterogeneity problem. The letters is characterized by fuel material with a stochastic dispersion of heterogeneous grains, and until now was solved with a model based on collision probabilities. We propose a new statistical model based on renewal-Markovian theory, which makes possible to take into account the stochastic nature of the problem and to avoid the approximations of the collision probability model. The numerical solution of this model is guaranteed by the method of characteristics. (author)

  14. Discontinuous finite element and characteristics methods for neutrons transport equation solution in heterogeneous grids; Resolution de l'equation du transport des neutrons par les methodes des elements finis discontinus et des caracteristiques structurees appliquees a des maillages heterogenes

    Energy Technology Data Exchange (ETDEWEB)

    Masiello, E

    2006-07-01

    The principal goal of this manuscript is devoted to the investigation of a new type of heterogeneous mesh adapted to the shape of the fuel pins (fuel-clad-moderator). The new heterogeneous mesh guarantees the spatial modelling of the pin-cell with a minimum of regions. Two methods are investigated for the spatial discretization of the transport equation: the discontinuous finite element method and the method of characteristics for structured cells. These methods together with the new representation of the pin-cell result in an appreciable reduction of calculation points. They allow an exact modelling of the fuel pin-cell without spatial homogenization. A new synthetic acceleration technique based on an angular multigrid is also presented for the speed up of the inner iterations. These methods are good candidates for transport calculations for a nuclear reactor core. A second objective of this work is the application of method of characteristics for non-structured geometries to the study of double heterogeneity problem. The letters is characterized by fuel material with a stochastic dispersion of heterogeneous grains, and until now was solved with a model based on collision probabilities. We propose a new statistical model based on renewal-Markovian theory, which makes possible to take into account the stochastic nature of the problem and to avoid the approximations of the collision probability model. The numerical solution of this model is guaranteed by the method of characteristics. (author)

  15. Metallic elements in fossil fuel combustion products: amounts and form of emissions and evaluation of carcinogenicity and mutagenicity.

    Science.gov (United States)

    Vouk, V B; Piver, W T

    1983-01-01

    Metallic elements contained in coal, oil and gasoline are mobilized by combustion processes and may be emitted into the atmosphere, mainly as components of submicron particles. The information about the amounts, composition and form of metal compounds is reviewed for some fuels and combustion processes. Since metal compounds are always contained in urban air pollutants, they have to be considered whenever an evaluation of biological impact of air pollutants is made. The value of currently used bioassays for the evaluation of the role of trace metal compounds, either as major biologically active components or as modifiers of biological effects of organic compounds is assessed. The whole animal bioassays for carcinogenicity do not seem to be an appropriate approach. They are costly, time-consuming and not easily amenable to the testing of complex mixtures. Some problems related to the application and interpretation of short-term bioassays are considered, and the usefulness of such bioassays for the evaluation of trace metal components contained in complex air pollution mixtures is examined.

  16. CONCEPTION OF USE VIBROACOUSTIC SIGNALS AND NEURAL NETWORKS FOR DIAGNOSING OF CHOSEN ELEMENTS OF INTERNAL COMBUSTION ENGINES IN CAR VEHICLES

    Directory of Open Access Journals (Sweden)

    Piotr CZECH

    2014-03-01

    Full Text Available Currently used diagnostics systems are not always efficient and do not give straightforward results which allow for the assessment of the technological condition of the engine or for the identification of the possible damages in their early stages of development. Growing requirements concerning durability, reliability, reduction of costs to minimum and decrease of negative influence on the natural environment are the reasons why there is a need to acquire information about the technological condition of each of the elements of a vehicle during its exploitation. One of the possibilities to achieve information about technological condition of a vehicle are vibroacoustic phenomena. Symptoms of defects, achieved as a result of advanced methods of vibroacoustic signals processing can serve as models which can be used during construction of intelligent diagnostic system based on artificial neural networks. The work presents conception of use artificial neural networks in the task of combustion engines diagnosis.

  17. Decontamination of irradiated fuel processing waste using lead paraperiodate; Decontamination des effluents de traitement des combustibles irradies par le paraperiodate de plomb

    Energy Technology Data Exchange (ETDEWEB)

    Auchapt, J M [Commissariat a l' Energie Atomique, Chusclan (France). Centre de Production de Plutonium de Marcoule

    1967-07-01

    The process is designed to eliminate ruthenium. It consists in an oxidation using para-periodic acid whose excess, acting then as a carrying-over agent, is precipitated in the form of a lead salt at a pH of 5 or 6. This process makes it possible to precipitate 80 to 98 per cent of the ruthenium which is not removed by the conventional precipitation techniques which follow it. If the waste is a reducing agent, it is pre-oxidized using ozone or potassium permanganate. The process was developed at Marcoule in 1963 and has since 1965 been applied industrially; its cost price is of the same order of magnitude as conventional processes and its results are satisfactory. (author) [French] Le procede est destine a l'elimination du ruthenium. Il consiste en une oxydation par l'acide par paraperiodique dont l'exces, jouant alors le role d'entraineur, est precipite sous forme de sel de plomb a pH 5 ou 6. Ce traitement permet de precipiter 80 a 98 pour cent du ruthenium rebelle aux traitements de precipitation classique, qui doivent le suivre. Si l'effluent est reducteur il est preoxyde a l'ozone ou au permanganate de potassium. Mis au point a Marcoule en 1963, il est depuis 1965 exploite industriellement, son prix de revient est du meme ordre de grandeur que celui des traitements habituels et les resultats ont donne satisfaction. (auteur)

  18. Ash-forming elements in four Scandinavian wood species part 3: Combustion of five spruce samples

    Energy Technology Data Exchange (ETDEWEB)

    Werkelin, Johan; Lindberg, Daniel; Skrifvars, Bengt-Johan; Hupa, Mikko [Aabo Akademi Process Chemistry Centre, Piispankatu 8, FI-20500 Turku (Finland); Bostroem, Dan [Energy Technology and Thermal Process Chemistry, Umeaa University, SE-901 87 Umeaa (Sweden)

    2011-01-15

    Forest residue is the remaining fraction after the outtake of timber, which comprises the tree tops and branches. It may as fuel cause damage to the combustion device through ash slagging and fouling. The objective of this work was to model the ash composition from well-specified samples of a spruce tree: wood, bark, twigs, needles, and shoots. Their ash at 1000 C was modelled using global chemical equilibrium calculations, and laboratory-made ash of the five samples was analyzed by XRD and SEM-EDXA. According to the results, the risk of slagging arises from the spruce foliage: molten alkali silicates from spruce needles and probably molten alkali phosphates from spruce shoots may cause problems in the furnace. Fouling caused by condensing alkali vapours can be produced by all five samples. The amount of alkali vapours in the flue gas was in the same order of magnitude for all five samples, in spite of large differences in their original alkali contents. (author)

  19. New class of combustion processes

    International Nuclear Information System (INIS)

    Merzhanov, A.G.; Borovinskaya, I.P.

    1975-01-01

    A short review is given of the results of work carried out since 1967 on studying the combustion processes caused by the interaction of chemical elements in the condensed phase and leading to the formation of refractory compounds. New phenomena and processes are described which are revealed when investigating the combustion of the systems of this class, viz solid-phase combustion, fast combustion in the condensed phase, filtering combustion, combustion in liquid nitrogen, spinning combustion, self-oscillating combustion, and repeated combustion. A new direction in employment of combustion processes is discussed, viz. a self-propagating high-temperature synthesis of refractory nitrides, carbides, borides, silicides and other compounds

  20. Release and Transformation of Inorganic Elements in Combustion of a High-Phosphorus Fuel

    DEFF Research Database (Denmark)

    Wu, Hao; Castro, Maria; Jensen, Peter Arendt

    2011-01-01

    The release and transformation of inorganic elements during grate-firing of bran was studied via experiments in a laboratory-scale reactor, analysis of fly ash from a grate-fired plant, and equilibrium modeling. It was found that K, P, S, and to a lesser extent Cl and Na were released to the gas...

  1. Environmental mineralogy - Understanding element behavior in ecosystems; Mineralogie environnementale: comprendre le comportement des elements dans les ecosystemes

    Energy Technology Data Exchange (ETDEWEB)

    Brown Jr, G.E. [Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305-2115 (United States); Department of Photon Science and Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Calas, G. [Institut de mineralogie et de physique des milieux condenses (IMPMC), universite Paris-6 - universite Paris-7, IPGP, CNRS, case 115, 75252 Paris (France)

    2011-02-15

    Environmental Mineralogy has developed over the past decade in response to the recognition that minerals are linked in many important ways with the global ecosystem. Minerals are the main repositories of the chemical elements in Earth's crust and thus are the main sources of elements needed for the development of civilization, contaminant and pollutant elements that impact global and local ecosystems, and elements that are essential plant nutrients. These elements are released from minerals through natural processes, such as chemical weathering, and anthropogenic activities, such as mining and energy production, agriculture and industrial activities, and careless waste disposal. Minerals also play key roles in the biogeochemical cycling of the elements, sequestering elements and releasing them as the primary minerals in crustal rocks undergo various structural and compositional transformations in response to physical, chemical, and biological processes that produce secondary minerals and soils. These processes have resulted in the release of toxic elements such as arsenic in groundwater aquifers, which is having a major impact on the health of millions of people in South and Southeast Asia. The interfaces between mineral surfaces and aqueous solutions are the locations of most chemical reactions that control the composition of the natural environment, including the composition of natural waters. The nuclear fuel cycle, from uranium mining to the disposition of high-level nuclear waste, is also intimately related to minerals. A fundamental understanding of these processes requires molecular-scale information about minerals, their bulk structures and properties such as solubility, their surfaces, and their interactions with aqueous solutions, atmospheric and soil gases, natural organic matter, and biological organisms. Gaining this understanding is further complicated by the presence of natural, incidental, and manufactured nano-particles in the environment

  2. The future of the nuclear wastes and the spent fuels at the United States; Le devenir des dechets nucleaires et des combustibles uses aux Etats-Unis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The USA regulation distinguishes three classes of nuclear wastes: the low activity wastes under the federal states control, the wastes contaminated by long life radionuclides (transuranic elements) and the high activity wastes. The two last classes are controlled by the DOE (Department of energy). The different classes management are discussed as the DOE obligations towards the operators, the storage project of Yucca Mountain and Private fuel storage of Skull Valley. (A.L.B.)

  3. Fabrication and Testing of Prototype APM-Clad UO{sub 2} Fuel Elements; Fabrication et essai de prototypes de cartouches de combustible en bioxyde d'uranium gaine d'aluminium (APM); Izgotovlenie i ispytanie prototipa toplivnykh ehlementov na osnove UO{sub 2} s obolochkoj iz alyuminiya metodom poroshkovoj metallurgii; Elaboracion y ensayo de elementos combustibles prototipo de UO{sub 2} con revestimiento de aluminio sinterizado

    Energy Technology Data Exchange (ETDEWEB)

    Ballif, III, J. L.; Friske, W. H.; Gordon, R. B. [Atomics International, Canoga Park, California (United States)

    1963-11-15

    elements had been removed from the reactor as a result of problems encountered with instrumentation associated with their tests. The other three elements were still in the reactor. The results of the experimental work to date give every indication that the APM-UO{sub 2} fuel system will achieve the goals set for the POPR programme. (author) [French] Dans le cadre du programme execute avec le ''Prototype Organic Power Reactor'' (POPR) de 50 MWe, des travaux importants ont ete entrepris en vue de mettre au point des produits de la metallurgie des poudres d'aluminium (APM) utilisables comme gaines d'elements combustibles en bioxyde d'uranium. Dans le cadre de ces travaux on a etudie des procedes d'emploi de melanges eutectiques, de soudure directe a Tare et de soudure par pression a froid (Kolweld) pour obturer l'extiemite des gaines. On a etudie l'emploi des vibrations pour le remplissage des gaines d'APM en combustible UO{sub 2}. Des essais hors pile ont ete faits pour recueillir des renseignements sur la compatibilite entre les produits APM et le bioxyde d'uranium. Les etudes ont revele que, dans les conditions actuelles, le recours aux melanges eutectiques etait la meilleure methode d'obturation des extremites; le remplissage par vibration a permis d'atteindre des densites de combustible de l'ordre de 80 a 88% de la valeur theorique et aucune reaction n'a ete observee entre les produits APM et UO{sub 2} dans la gamme des temperatures de fonctionnement de POPR (temperature maximum a l'interface combustible/gaine-455{sup o}C). A la suite de ces travaux preliminaires, on a fabrique cinq prototypes de cartouches de combustibles en UO{sub 2} gaine d'APM, que Gop a essayes dans le reacteur experimental a ralentisseur organique (OMRE). Chaque cartouche consistait en 24 ou 25 barreaux gaines d'APM, disposes en 5 rangees de 5 dans un recipient en acier nickele ou en aluminium APM. Pour ameliorer les echanges thermiques, les gaines d'APM extrudees etaient munies de 8 ailettes

  4. Non-Destructive Testing Methods Applied to Multi-Finned SAP Tubing for Nuclear-Fuel Elements; Essais Non Destructifs de Gaines a Ailettes, en Poudre d'Aluminium Frittee, pour Elements Combustibles; Nedestruktivnye metody ispytaniya rebristykh trub iz spechennogo alyuminikiog'o poroshka dlya yadernykh toplivnykh ehlementov; Metodos de Ensayo No Destructivo Aplicados a Tubos de SAP con Aletas Multiples Destinados a Elementos Combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Lund, S. A. [Danish Central Welding Institution, Copenhagen (Denmark); Knudsen, P. [Danish Atomic Energy Commission, Research Establishment, Risoe (Denmark)

    1965-09-15

    contient des pastilles de bioxyde d'uranium fritte, dans une gaine de 2'm de long en poudre d'aluminium frittee portant des ailettes disposees en configuration helicoiedale. Ces gaines doivent repondre a des specifications tres strictes pour que soient realisees les conditions optimales de transfert de chaleur et que soit maintenue l'integrite des elements combustibles aussi longtemps qu'ils restent dans le reacteur. Deux exemples de modeles de gaines montrent a quel point les tolerances di- mensionnelles sont faibles. Afin de s'assurer que les gaines repondent bien aux specifications, on procede a un controle extremement rigoureux, constitue en grande partie par des essais non destructifs. Les auteurs decrivent les methodes d'essais non destructifs mises au point pour mesurer l'epaisseur de la paroi et les diametres et pour deceler les defectuosites. En raison de la geometrie complexe de sa section, le modele a 24 ailettes ne se prete pas a l'application de methodes par les ultrasons ou par les courants de Foucault pour mesurer l'epaisseur de la paroi. On a donc mis au point une jauge a rayons beta speciale, pourvue d'un dispositif d'enregistrement; elle est fondee sur l'attenuation du rayonnement beta emis par une source au {sup 90}Sr placee a l'interieur de la gaine. Pour le modele a 12 ailettes, on utilise une methode de resonance ultrasonore en immersion pour l'enregistrement continu de l'epaisseur de la paroi. On mesure, en enregistrement continu, les diametres interieur et exterieur (au niveau des tetes d'ailettes) avec des appareils comportant une jauge a air rapide. Pour la detection des defectuosites, on applique la methode ultrasonore impulsion-echo, en immersion, et la methode des courants de Foucault. La methode ultrasonore permet de deceler facilement les fissures transversales, mais elle ne semble pas applicable a la detection des fissures longitudinales; c'est pourquoi on la complete par la methode des courants de Foucault. (author) [Spanish] La Comision de

  5. Review of safety precautions derived from six-year experience of a spent fuel reprocessing plant - Centre de Marcoule; Elements de securite tires de six annees d'exploitation de l'usine de traitement de combustibles irradies du Centre de Marcoule

    Energy Technology Data Exchange (ETDEWEB)

    Rodier, J [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

    1964-07-01

    an organization of the work aimed at eliminating the causes of incidents. They investigate the following points in particular: - frequency of entry into forbidden zones during normal functioning - the distribution of exceptional tasks - the prevention of criticality risks - zone contamination incidents - the volume and nature of decontaminated material and eliminated residues - the evolution and distribution of external irradiation doses received by the workers - the frequency of cases of body contamination - internal contamination fixed in the organisms of workers. Conclusions are drawn from the different incidents which have occurred during the years of operating the plant. (author) [French] Dans une usine de traitement de combustibles irradies comme dans toute autre usine, la continuite de la production ne peut etre obtenue que par une recherche constante de la securite. Les auteurs examinent les elements de securite apportes par la conception des installations tant au point de vue de la securite classique que de la securite radiologique. Dans l'industrie nucleaire, il ne suffit pas, en effet, d'adopter seulement les precautions habituelles prises contre les risques d'explosion, d'incendie...; il faut aussi apporter beaucoup d'attention aux problemes poses par le confinement des matieres, la radioactivite et les risques de criticite. Les principes generaux de la prevention technique contre les risques radioactifs sont maintenant bien connus. Leur application doit se traduire des la conception des installations par des dispositions concernant: - la conception et la realisation des installations vis-a-vis des risques deja enumeres, - la division de l'usine en zones, - la circulation du personnel et du materiel, - la ventilation et l'epuration de l'air. Les facteurs techniques de securite ne sont toutefois pas suffisants a eux seuls. Quelle que soit la qualite du materiel et le degre d'automatisme atteint, la continuite de fonctionnement d'une usine implique l

  6. Combustion Dynamics and Stability Modeling of a Liquid Oxygen/RP-2 Oxygen-Rich Staged Combustion Preburner and Thrust Chamber Assembly with Gas-Centered Swirl Coaxial Injector Elements

    Science.gov (United States)

    Casiano, M. J.; Kenny, R. J.; Protz, C. S.; Garcia, C. P.; Simpson, S. P.; Elmore, J. L.; Fischbach, S. R.; Giacomoni, C. B.; Hulka, J. R.

    2016-01-01

    The Combustion Stability Tool Development (CSTD) project, funded by the Air Force Space and Missile Systems Center, began in March 2015 supporting a renewed interest in the development of a liquid oxygen/hydrocarbon, oxygen-rich combustion engine. The project encompasses the design, assembly, and hot-fire testing of the NASA Marshall Space Flight Center 40-klbf Integrated Test Rig (MITR). The test rig models a staged-combustion configuration by combining an oxygen-rich preburner (ORPB), to generate hot gas, with a thrust chamber assembly (TCA) using gas-centered swirl coaxial injector elements. There are five separately designed interchangeable injectors in the TCA that each contain 19- or 27- injector elements. A companion paper in this JANNAF conference describes the design characteristics, rationale, and fabrication issues for all the injectors. The data acquired from a heavily instrumented rig encompasses several injectors, several operating points, and stability bomb tests. Another companion paper in this JANNAF conference describes this test program in detail. In this paper, dynamic data from the hot-fire testing is characterized and used to identify the responses in the ORPB and TCA. A brief review of damping metrics are discussed and applied as a measure of stability margin for damped acoustic modes. Chug and longitudinal combustion stability models and predictions are described which includes new dynamic models for compressible flow through an orifice and a modification to incorporate a third feed line for inclusion of the fuel-film coolant. Flow-acoustics finite element modeling is used to investigate the anticipated TCA acoustics, the effects of injector element length on stability margin, and the potential use of an ORPB orifice trip ring for improving longitudinal stability margin.

  7. Personnel Dosimeters with Radiation Elements; Dosimetres Individuels Comportant des Elements Emetteurs; 0418 041d 0414 0418 0412 0418 0414 ; Dosimetros Individuales Provistos de Elementos Emisores

    Energy Technology Data Exchange (ETDEWEB)

    Hosemann, R.; Warrikhoff, H. F.H. [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin-Dahlem, Federal Republic of Germany (Germany)

    1965-06-15

    The radiation element is a vacuum diode, the electrodes of which emit a different charge of electrons per unit of irradiation. Since the electrons ejected leave one electrode with a high energy, the other electrode will be charged to proportionally high voltages without any auxiliary power. Accordingly these direct reading systems are called radiation elements. When measuring X- and y-rays, one electrode consists of lead, the other of carbon. The wavelength independence with regard to the r-unit was obtained by the electron-filtering method. The sensitivity is approximately 0.5 V/r {+-} 8% within the range from 80 keV to 1.25 MeV. (Full scale 200-2000 r either linear or quasi logarithm. ) When measuring slow and fast neutrons, the induced {beta}-activity of the electrodes charge the built-in electrometer. It is possible to measure both gamma radiation and neutrons in rem units with one instrument. The neutron sensitivity of a gamma element can be made definitely zero, but the gamma sensitivity of a neutron element presents some difficulties. The outstanding advantages of these instruments are: (1) Self-powered systems, always ready to function, unlimited storing time, no batteries or charging units; (2) Extremely low fading because of the use of vacuum and quartz for isolation; (3) Quantitative measurement of the highest attainable dose rates because of no recombination effects (vacuum) ; and (4) Either direct or indirect systems. The direct reading instrument contains the radiation element and the electrometer in the same vacuum vessel. There are no electrical contacts outside the instrument. Cylindrical and spherical designs of the element are preferable to other geometries. The outer dimensions of the instrument will be the same as those of the commonly used pen-type dosimeters. Each system contains a discharge switch and a control unit. (author) [French] L'element emetteur est constitue par une diode a vide dont les electrodes emettent des flux d

  8. The development of a cell-assembly for the treatment of irradiated fuels on a semi-industrial scale; Etude concernant la realisation d'un ensemble de cellules destinees a des traitements de combustibles irradies a l'echelle semi-industrielle

    Energy Technology Data Exchange (ETDEWEB)

    Faugeras, P; Couture, J; Lefort, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    The main studies and experiments involved in the development of a cell-assembly for the treatment of irradiated fuels on a semi-industrial scale are described. It must be possible to modify or transform each of these cells without interrupting the rest of the pilot. A full-scale prototype cell (3 x 4 x 6 m) has been built with an {alpha}-protection independent of the {gamma}-protection. It features all the main characteristics: tightness to {gamma} losses, dense glass lighting, ventilation. This cell has made possible trials on transfer, remote-controls and tele-dismantling, as well as the development of new methods of rapidly connecting hydraulic circuits. In conclusion the final form is given of the cells selected for the pilot. (author) [French] Il est decrit les principales etudes et experiences faites en vue de la realisation d'un ensemble de cellules destinees a des traitements de combustibles irradies a l'echelle semi-industrielle. Chacune de ces cellules doit pouvoir etre modifiee ou transformee sans interrompre le reste du pilote. Une cellule prototype vraie grandeur (3x4x6 m) est construite avec une protection {alpha} independante de la protection {gamma}. Elle comporte tous les elements importants: porte {gamma} etanche, eclairage verre dense, ventilation. Cette cellule a permis des experiences de transferts de telemanipulateurs et de teledemontages, ainsi que la mise au point de nouveaux procedes de jonction rapide pour des circuits hydrauliques. En conclusion, on indique la forme definitive des cellules retenues pour le pilote. (auteur)

  9. Elevated standard metabolic rate in a freshwater shrimp (Palaeomonetes paludosus) exposed to trace element-rich coal combustion waste

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, C.L. [University of Georgia, Aiken, SC (United States). Savannah River Ecology Lab.

    1998-12-01

    A transplant experiment was conducted to determine whether standard metabolic rate (SMR) of a freshwater shrimp (Palaeomonetes paludosus) would be affected by exposure to trace element-enriched coal combustion waste (coal ash). Shrimp were transplanted into replicate cages in a coal ash-polluted site and a reference site for 8 months. The coal ash-polluted site was characterized by elevated sediment concentrations of As, Cd, Cr, Cu, Ni, Pb and Se compared to sediments in the reference site. After 8 months in the study sites, shrimp in the polluted site appeared to have accumulated As, Cd and Se from the habitat, but there were on differences in survival between the study sites. However, mean SMR of shrimp (measured as O{sub 2} consumption at rest) held in the polluted site was 51% higher than mean SMR of shrimp held in the reference site. The elevation in SMR indicates that the energetic costs of maintenance are greater for shrimp chronically exposed to the coal-ash polluted enviorment than shrimp in the reference site. It is likely, therefore, that other physiological or behavioral processes may be modified in the pollution-exposed individuals to compensate for the increased energy demands for maintenance. Recent studies have reported similar elevations in SMR in an amphibian and a reptile chronically exposed to coal ash. Analogous physiological responses in such taxonomically diverse animals (a crustacean, an amphibian, and a reptile) indicate that elevated SMR may be a general response by many types of organisms exposed to the mixture of trace elements characteristic of coal ash. The relationships among pollution-induced elevations in maintenance expenditures, long-term health of individuals, and population-level parameters require further attention. 19 refs., 1 fig., 1 tab.

  10. Partitioning of selected trace elements in coal combustion products from two coal-burning power plants in the United States

    Science.gov (United States)

    Swanson, Sharon M.; Engle, Mark A.; Ruppert, Leslie F.; Affolter, Ronald H.; Jones, Kevin B.

    2013-01-01

    Samples of feed coal (FC), bottom ash (BA), economizer fly ash (EFA), and fly ash (FA) were collected from power plants in the Central Appalachian basin and Colorado Plateau to determine the partitioning of As, Cr, Hg, Pb, and Se in coal combustion products (CCPs). The Appalachian plant burns a high-sulfur (about 3.9 wt.%) bituminous coal from the Upper Pennsylvanian Pittsburgh coal bed and operates with electrostatic precipitators (ESPs), with flue gas temperatures of about 163 °C in the ESPs. At this plant, As, Pb, Hg, and Se have the greatest median concentrations in FA samples, compared to BA and EFA. A mass balance (not including the FGD process) suggests that the following percentages of trace elements are captured in FA: As (48%), Cr (58%), Pb (54%), Se (20%), and Hg (2%). The relatively high temperatures of the flue gas in the ESPs and low amounts of unburned C in FA (0.5% loss-on-ignition for FA) may have led to the low amount of Hg captured in FA. The Colorado Plateau plant burns a blend of three low-S (about 0.74 wt.%) bituminous coals from the Upper Cretaceous Fruitland Formation and operates with fabric filters (FFs). Flue gas temperatures in the baghouses are about 104 °C. The elements As, Cr, Pb, Hg, and Se have the greatest median concentrations in the fine-grained fly ash product (FAP) produced by cyclone separators, compared to the other CCPs at this plant. The median concentration of Hg in FA (0.0983 ppm) at the Colorado Plateau plant is significantly higher than that for the Appalachian plant (0.0315 ppm); this higher concentration is related to the efficiency of FFs in Hg capture, the relatively low temperatures of flue gas in the baghouses (particularly in downstream compartments), and the amount of unburned C in FA (0.29% loss-on-ignition for FA).

  11. Valorization of used tyres as fuel substitute in cement industry; Valorisation des pneus usages comme combustible de substitution en cimenterie

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1999-03-01

    According to the French syndicate of cement industry, more than 350000 t of worn tyres are produced each year in France, among which only 143000 t are reused in retreading, exported as used tyres or valorized in cement industry. The rest is generally tipped or burnt in the open-air. In cement kilns, the organic matters of tyres are completely burnt while the metal belts supply the necessary amount of iron to the cement composition. The combustion of tyres produces no black smoke, no smell and no ash and has no significant influence on the effluents of cement factories: gases are directly filtered in the kiln by the important mass of raw materials which acts as quicklime. In 1997, 31500 t of used tyres were burnt in the seven French cement factories over 34 that use this kind of fuel and represents 1.5% of the total energy needs. This substitution ratio could easily reach 10 to 15% without leading to any additional environmental or technical problem. A project of collection and valorization of used tyres has been developed by the French ministry of environment and aims at completely eliminating tyres tipping since July 1, 2002. In order to illustrate the French policy of tyres valorization, two examples of actions are presented in this paper: the first one is carried out by the Michelin manufacturer in order to facilitate the recycling of civil engineering tyres, and the second is carried out by Ciments d`Origny company at the Rochefort factory where tyres are used as fuel substitutes. (J.S.)

  12. Developpement d'un modele analytique pour l'analyse en elasticite lineaire de champs de deformation et contrainte au sein d'un polycristal. comparaison avec la methode des elements finis =

    Science.gov (United States)

    Bretin, Remy

    L'endommagement par fatigue des materiaux est un probleme courant dans de nombreux domaines, dont celui de l'aeronautique. Afin de prevenir la rupture par fatigue des materiaux il est necessaire de determiner leur duree de vie en fatigue. Malheureusement, dues aux nombreuses heterogeneites presentes, la duree de vie en fatigue peut fortement varier entre deux pieces identiques faites dans le meme materiau ayant subi les memes traitements. Il est donc necessaire de considerer ces heterogeneites dans nos modeles afin d'avoir une meilleure estimation de la duree de vie des materiaux. Comme premiere etape vers une meilleure consideration des heterogeneites dans nos modeles, une etude en elasticite lineaire de l'influence des orientations cristallographiques sur les champs de deformations et de contraintes dans un polycristal a ete realisee a l'aide de la methode des elements finis. Des correlations ont pu etre etablies a partir des resultats obtenus, et un modele analytique en elasticite lineaire prenant en compte les distributions d'orientations cristallographiques et les effets de voisinage a pu etre developpe. Ce modele repose sur les bases des modeles d'homogeneisation classique, comme le schema auto-coherent, et reprend aussi les principes de voisinage des automates cellulaires. En prenant pour reference les resultats des analyses elements finis, le modele analytique ici developpe a montre avoir une precision deux fois plus grande que le modele auto-coherent, quel que soit le materiau etudie.

  13. New Methods and Facilities for the Measurement of Physical Properties of Reactor Components and Irradiated Materials; Nouveaux Procedes et Instruments de Mesure des Proprietes Physiques des Elements de Reacteur et des Matieres Irradiees; Novye metody i sredstva izmereniya fizicheskikh s vojstv komponentov reaktora i obluchennykh materialov; Nuevos Metodos y Equipos para Medir Propiedades Fisicas de Componentes de Reactor y de Materiales Irradiados

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, F.; Mueller, P. [Institut Dr. Foerster, Reutlingen, Federal Republic of Germany (Germany)

    1965-09-15

    zone 'chaude ' du reacteur. Ils discutent la relation entre la conductivite electrique et la dose d'irradiation. Les auteurs decrivent un instrument de mesure de la permeabilite, de la remanence et de la force co- ercitive en fonction des contraintes mecaniques, de la deformation elastique et inelastique et de la dose d'irradiation. Ils donnent des mesures de la variation des proprietes magnetiques en fonction des contraintes elastiques et de la deformation inelastique. Ils etudient les effets de l'irradiation sur la permeabilite et sur la force coercitive. Les auteurs decrivent un instrument permettant la mesure rapide et la lecture directe de la permeabilite des elements en acier inoxydable. Ils expliquent la correlation entre la permeabilite et la teneur en ferrite {Delta}. Us discutent certaines mesures du pourcentage de ferrite {Delta} dans les soudures de tubes en acier inoxydable ainsi que certaines mesures de precipitation de ferrite {Delta} en fonction de la deformation inelastique (forgeage a la main d'elements combustibles pour reacteurs). (author) [Spanish] Se describe un intrumento para medir y registrar en forma totalmente automatica el modulo de Young, el modulodecorte y la capacidad de amortiguamiento, en funcion de la temperatura y el tiempo. El modulo de Young se determina excitando muestras de diversos tamanos con sus frecuencias naturales, mientras que la capacidad de amortiguamiento se mide en funcion de la libre atenuacion de la vibracion, o bien por la anchura media de la curva de resonancia. Se presentan ejemplos de medidas de la recuperacion despues de provocar danos por irradiaciones y deformaciones plasticas asf como grado de grafitacion. Se describe la deteccion de fallas y variaciones de densidad en barras de grafito. Se explica, ademas, un metodo para investigar la retencion de pastillas de UO{sub 2} en tubos austenfticos de pared delgada. Se describe un horno especial para estudiar el comportamiento elastico e inelastico de muestras

  14. Engine 3E. NO{sub x} reduction by means of homogenisation of mixtures inside combustion chambers. Final report; Engine 3E. NO{sub x}-Reduktion durch Homogenisierung des Gemisches in Brennkammern. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Zarzalis, N.; Homann; Schubert

    1999-11-05

    This is the final report of the Technology Project 'NO{sub x} reduction by means of homogenisation of mixtures inside combustion chambers', which is part of the Engine 3E 2010 programme of the BMBF, which was to promote research in aircraft engineering. In this project, technologies were developed to achieve a 60% reduction of NO{sub x} emissions as compared to ICAO '95 in an annular combustion chamber in realistic operating conditions where the emissions of substances oher than NO{sub x} were to be of the same level as the emissions of modern jet drives. Further, the design of the new combustion chamber was to be conventional in order to retain the possibility of converting existing propulsion systems to the new technology. [German] Diese Notiz enthaelt den Abschlussbericht des Technologievorhabens 'NO{sub x}-Reduktion durch Homogenisierung des Gemisches in Brennkammern'. Das Vorhaben ist Teil des Luftfahrtfoerderprogramms Engine 3E 2010 der Bundesregierung und wird vom Bundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie (BMBF) unter dem Foerderkennzeichen 20T9540 gefoerdert. Das Programm wurde am 01. Juli 1995 begonnen und endete am 30. Juni 1999. Entsprechend dem Foerderantrag wurden in dem Vorhaben Einzeltechnologien erarbeitet, die erforderlich sind, um eine 60% Reduktion der NO{sub x}-Emissionen gegenueber ICAO '95 in einer Ringbrennkammer unter realistischen Betriebsbedingungen zu demonstrieren, wobei die restlichen Emissionen das Emissionsniveau moderner Triebwerke nicht ueberschreiten sollten. Darueber hinaus sollte das aeussere Design der zu entwickelnden Brennkammer sind von konventionellen Brennkammern nicht unterscheiden, um die Moeglichkeit der Umruestung von alten Triebwerken mit der Brennkammern der neuen Technologie offen zu halten. (orig.)

  15. Development of Nano-Sulfide Sorbent for Efficient Removal of Elemental Mercury from Coal Combustion Fuel Gas.

    Science.gov (United States)

    Li, Hailong; Zhu, Lei; Wang, Jun; Li, Liqing; Shih, Kaimin

    2016-09-06

    The surface area of zinc sulfide (ZnS) was successfully enlarged using nanostructure particles synthesized by a liquid-phase precipitation method. The ZnS with the highest surface area (named Nano-ZnS) of 196.1 m(2)·g(-1) was then used to remove gas-phase elemental mercury (Hg(0)) from simulated coal combustion fuel gas at relatively high temperatures (140 to 260 °C). The Nano-ZnS exhibited far greater Hg(0) adsorption capacity than the conventional bulk ZnS sorbent due to the abundance of surface sulfur sites, which have a high binding affinity for Hg(0). Hg(0) was first physically adsorbed on the sorbent surface and then reacted with the adjacent surface sulfur to form the most stable mercury compound, HgS, which was confirmed by X-ray photoelectron spectroscopy analysis and a temperature-programmed desorption test. At the optimal temperature of 180 °C, the equilibrium Hg(0) adsorption capacity of the Nano-ZnS (inlet Hg(0) concentration of 65.0 μg·m(-3)) was greater than 497.84 μg·g(-1). Compared with several commercial activated carbons used exclusively for gas-phase mercury removal, the Nano-ZnS was superior in both Hg(0) adsorption capacity and adsorption rate. With this excellent Hg(0) removal performance, noncarbon Nano-ZnS may prove to be an advantageous alternative to activated carbon for Hg(0) removal in power plants equipped with particulate matter control devices, while also offering a means of reusing fly ash as a valuable resource, for example as a concrete additive.

  16. Study of physico-chemical release of uranium and plutonium oxides during the combustion of polycarbonate and of ruthenium during the combustion of solvents used in the reprocessing of nuclear fuel; Etude de la mise en suspension physico-chimique des oxydes de plutonium et d'uranium lors de la combustion de polycarbonate et de ruthenium lors de la combustion des solvants de retraitement du combustible irradie

    Energy Technology Data Exchange (ETDEWEB)

    Bouilloux, L

    1998-07-01

    The level of consequences concerning a fire in a nuclear facility is in part estimated by the quantities and the physico-chemical forms of radioactive compounds that may be emitted out of the facility. It is therefore necessary to study the contaminant release from the fire. Because of the multiplicity of the scenarios, two research subjects were retained. The first one concerns the study of the uranium or plutonium oxides chemical release during the combustion of the polycarbonate glove box sides. The second one is about the physico chemical characterisation of the ruthenium release during the combustion of an organic solvent mixture (tributyl phosphate-dodecane) used for the nuclear fuel reprocessing. Concerning the two research subjects, the chemical release, i.e. means the generation of contaminant compounds gaseous in the fire, was modelled using thermodynamical simulations. Experiments were done in order to determine the ruthenium release factor during solvent combustion. A cone calorimeter was used for small scale experiments. These results were then validated by large scale tests under conditions close to the industrial process. Thermodynamical simulations, for the two scenarios studied. Furthermore, the experiments on solvent combustion allowed the determination of a suitable ruthenium release factor. Finally, the mechanism responsible of the ruthenium release has been found. (author)

  17. Heavy element concentration determination by the x-ray fluorescence analysis using radioisotope {gamma}-ray sources; Dosage d'elements lourds par fluorescence X utilisant des radio-sources de rayons gamma

    Energy Technology Data Exchange (ETDEWEB)

    Enomoto, S [Commissariat a l' Energie Atomique, Dir. des Materiaux et des Combustibles Nucleaires, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    A theoretical and experimental study has been made on the fluorescence analysis of high atomic number element, using {gamma}-ray sources for excitation and characteristic K X-rays for the measurement. The choice of the proper {gamma}-ray energy according to the conditions of the determination is considered. The author has studied the usefulness of using the backscattered {gamma}-rays as a correction mean for matrix and grain-size effects. Sources of {sup 153}Gd, {sup 57}Co, {sup 137}Cs have been used for excitation using collimated geometries. Concentration measurements of tungsten in steel, tungsten and lead in aqueous solution, PbS in SiO{sub 2}-PbS powder mixtures have been done, as well as thickness evaluation of gold layers on copper. A precision of about 0.2 per cent (abs.) is obtained for lead determination in light matrixes. A probe design is proposed for the continuous determination of lead in aqueous solutions. (author) [French] On etudie de maniere theorique et experimentale l'analyse d'elements a nombre atomique eleve par fluorescence en utilisant des sources de rayons {gamma} pour l'excitation, et des rayons-X K caracteristiques pour la mesure. On considere le choix de l'energie appropriee des rayons {gamma} suivant les conditions experimentales. L'utilite d'employer les rayons {gamma} retrodiffuses pour corriger les effets de la matrice et de la dimension des grains est etudiee. Des sources de {sup 153}Gd, de {sup 57}Co et de {sup 137}Cs a geometrie collimatee ont ete utilisees pour l'excitation. Des mesures de la concentration du tungstene dans l'acier, du tungstene et du plomb en solutions aqueuses, et du PbS dans des melanges de poudre SiO{sub 2}-PbS ont ete entreprises ainsi que l'evaluation de l'epaisseur des couches d'or sur le cuivre. On obtient une precision d'environ 0,2 pour cent (en absolu) pour la determination du plomb dans des matrices legeres. On propose un modele de sonde pour la determination en continu du plomb en solution aqueuse

  18. A Physics and Tabulated Chemistry Based Compression Ignition Combustion Model: from Chemistry Limited to Mixing Limited Combustion Modes Un modèle de combustion à allumage par compression basé sur la physique et la chimie tabulée : des modes de combustion contrôlés par la chimie jusqu’aux modes contrôlés par le mélange

    Directory of Open Access Journals (Sweden)

    Bordet N.

    2011-11-01

    experimental measurements carried out on a 2 liter Renault Diesel engine and good agreements are found. Ce papier présente une nouvelle approche 0D phénoménologique pour prédire le déroulement de la combustion dans les moteurs Diesel à injection directe pour toutes les conditions d’utilisation usuelles. Le but de ce travail est de développer une approche physique en vue d’améliorer la prédiction de la pression cylindre et du dégagement d’énergie, avec un nombre minimum d’essais nécessaires à la calibration. Les contributions principales de cette étude sont la modélisation de la phase de pré-mélange de la combustion et une extension du modèle pour les stratégies d’injections multiples. Dans ce modèle, le taux de dégagement d’énergie dû à la combustion pour la phase pré-mélangée est relié à un taux de réaction moyen du carburant. Ce taux de réaction moyen de carburant est évalué à l’aide d’une approche basée sur un taux de réaction local de carburant tabulé et la détermination d’une fonction de densité de probabilité (PDF de la fraction de mélange (Z. Cette PDF permet de prendre en compte la distribution de richesse existante dans la zone pré-mélangée. L’allure de cette PDF présumée est une β-fonction standardisée. Les fluctuations de la fraction de mélange sont décrites avec une équation de transport pour la variance de Z. La définition standard de la fraction de mélange, établie dans le cas de flammes de diffusion, est ici adaptée à une combustion pré-mélangée de type Diesel pour décrire l’inhomogénéité de la richesse dans le volume de contrôle. La chimie détaillée est décrite au travers de la tabulation du taux de réaction relatif à la flamme principale et du délai d’auto-inflammation relatif à la flamme froide, ces tabulations sont fonction de la variable d’avancement c, du taux de gaz brûlé ainsi que des grandeurs thermodynamiques telles que la température et la pression. Le

  19. Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: Main Ash-Forming Elements and Ash Distribution with a Focus on Phosphorus.

    Science.gov (United States)

    Skoglund, Nils; Grimm, Alejandro; Ohman, Marcus; Boström, Dan

    2014-02-20

    This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the distribution of main ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K 2 CO 3 ) and alkaline-earth metal (CaCO 3 ) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash distribution was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%-95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca 9 (K,Mg,Fe)(PO 4 ) 7 , for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO 2 ) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi 2 O 6 ) was formed. Most of the alkaline-earth metals

  20. The Performance of Major Plant Items at Calder Hall; Fonctionnement des elements principaux de la centrale de Calder Hall; Kharakteristika osnovnykh uzlov ustanovki v Kolder-Kholle; Rendimiento de los principales elementos de la central de Calder Hall

    Energy Technology Data Exchange (ETDEWEB)

    Desbruslais, E. L. [United Kingdom Atomic Energy Authority, Seascale, Cumberland (United Kingdom)

    1963-10-15

    dans les canaux a combustible, et de pinces speciales, a permis de reduire les temps de dechargement. On n'a enregistre que des defaillances mineures dans les mecanismes complexes de commande des barres de reglage et le materiel de controle connexe. Dans toute la mesure du possible le controle de l'usine doit etre centralise et les principaux centres de controle ainsi que les elements importants de l'usine doivent etre proteges de tout dommage accidentel pouvant provenir de l'exterieur. Pour la generatrice diesel de secours, il ne semble pas necessaire de prevoir le demarrage automatique et des circuits doubles, mais une centralisation ne serait pas inutile. (author) [Spanish] Desde hace mas de seis afios, Calder Hall viene funcionando como central para la carga basica, habiendo sufrido avenas similares a las que se registran en las centrales clasicas de electricidad. Todas las fallas se han producido en la parte clasica de la central y ninguna en los reactores propiamente dichos. La experiencia ha demostrado que, desde el punto de vista de la seguridad de los reactores, estos mismos y los principales elementos de la central, asi como las conexiones con la red, se han de considerar en conjunto. No se ha observado ningun cambio importante que sugiera que el recipiente de presion del reactor o el moderador de grafito limitaran la vida util de la central. La distribucion de temperatura alrededor de los conductos de salida de gas es asimetrica, lo cual limita actualmente la potencia del reactor. Se ha recomendado montar mas pares termoelectricos, asi como instrumentos para medir deformaciones y dispositivos que permitan observar visualmente zonas de tension y temperaturas elevadas. Durante el funcionamiento normal, no se emplean ya los desecadores Humidrier y gracias a ello se ha logrado un ligero aumento de la potencia del reactor. Se formulan algunas recomendaciones respecto de la frecuencia de las inspecciones de los intercambiadores de calor, de los principales

  1. Fixation and separation of the elements thorium and uranium using anion exchange resins in nitrate solution; Fixation et separation des elements thorium et uranium par les resines echangeuses d'anions en milieu nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Korgaonkar, V. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-10-01

    The exchange of thorium and uranium between a strong base anion resin and a mixed water + ethanol solvent containing nitrate ions is studied. It is assumed that in the resin the thorium and uranium are fixed in the form of the complexes Th(NO{sub 3}){sub 6}{sup 2-} and UO{sub 2}(NO{sub 3}){sub 4}{sup 2-} in solution these elements are present in the form of complexes having the general formula: Th(NO{sub 3}){sub 6-n}{sup n-2} and UO{sub 2}(NO{sub 3}){sub 4-n}{sup n-2} It has been possible to deduce a law for the changes in the partition functions of thorium and uranium as a function of the concentrations of the various species in solution and of the complexing ion NO{sub 3}. From this has been deduced the optimum operational conditions for separating a mixture of these two elements. Finally, in these conditions, the influence of a few interfering ions has been studied: Ba, Bi, Ce, La, Mo, Pb, Zr. The method proposed can be used either as a preparation, or for the dosage of thorium by a quantitative separation. (author) [French] On etudie l'echange du thorium et de l'uranium entre une resine anion base forte et un solvant mixte eau + ethanol charge en ions nitrates. On a suppose que, dans la resine, le thorium et l'uranium sont fixes sous forme de complexes Th(NO{sub 3}){sub 6}{sup 2-} et UO{sub 2}(NO{sub 3}){sub 4}{sup 2-} en solution, ces elements sont engages dans des complexes de formule generale: Th(NO{sub 3}){sub 6-n}{sup n-2} and UO{sub 2}(NO{sub 3}){sub 4-n}{sup n-2} On a pu degager une loi de variation des coefficients de partage du thorium et de l'uranium en fonction des concentrations des diverses especes en solution et de l'anion complexant NO{sub 3}{sup -}. On en a deduit les conditions operatoires optimales necessaires pour separer les deux elements a partir de leurs melanges. Enfin, dans ces conditions, on a etudie l'influence de quelques elements genants: Ba, Bi, Ce, La, Mo, Pb, Zr. La methode preconisee peut etre

  2. Contribution to the micro-calorimetric study of the characteristics of radio-elements and to their qualitative and quantitative analysis; Contribution a l'etude microcalorimetrique des caracteristiques des radio-elements et a leurs analyses qualitative et quantitative

    Energy Technology Data Exchange (ETDEWEB)

    Ozias, Y [Centre de Production de Plutonium de Marcoule, 30 (France)

    1964-10-01

    The principle of this study consists in using the E. CALVET microcalorimeter for recording the energy flux emitted by radio-elements as a function of time, and in determining from this curve either their characteristics (half-life and radiation energy), or the composition of a mixture of radio-elements. In the first part the theoretical relationships describing radioactivity have been adapted to the microcalorimetric study. In the second part an experimental determination has been made using the E. CALVET microcalorimeter of the characteristics of various radio-elements, yttrium 90, phosphorus 32, sulphur 35, iodine 131, etc and of their mixtures. In particular a study has been made of the isotopic analysis of a {sup 239}Pu - {sup 240}Pu mixture, sometimes in the presence of {sup 241}Pu. The microcalorimetric method is not as sensitive as conventional counting methods, its limit appears to be at the present about 1 micro-watt for the apparatus used, it is however the most direct method in the case of emitters of weakly absorbed radiation ({alpha} and {beta}). For the {gamma} emitters only a part of the energy is absorbed by the walls of the container. The determination of their characteristics and of their masses in the mixtures depends neither on the shape, on the dilution or even less on the auto-absorption of the source. For high activity samples this auto-absorption is the cause of great difficulties in conventional methods which complicate the operations: divisions, dissolutions, dilutions, all of which are liable to introduce errors. The calorimetric method makes it possible to work on the untreated sample. All these measurements have been carried out using the conventional E CALVET calorimeter; to carry out an exact measurement of the energy due to {gamma} radiation, however, it is necessary to build special apparatus with a lead block the size of which is given by the author's calculations. The calorimetric method makes it possible to attain an accuracy

  3. Study of cis- and trans-uranium elements by paper chromatography and electrophoresis; Contribution a l'etude des elements cis- et trans-uraniens par chromatographie sur papier et electrophorese

    Energy Technology Data Exchange (ETDEWEB)

    Clanet, F [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-01-01

    'electrophorese, en chimie minerale, a ete etendu aux elements 90 a 96 en milieux HCl et HNO{sub 3}. Les resultats obtenus portent sur les points suivants: 1) - Caracterisation des etats de valence de Np et de Pu a l'aide de reactions colorees sur les chromatogrammes et les electrophoregrammes. L'alizarine, l'arsenazo-I et le thorin-I permettent de caracteriser la valence IV, tandis que le diphenylcarbazide est specifique de l'etat hexavalent. 2) - Chromatographie sur papier: en utilisant comme eluants des melanges a parts egales de solutions aqueuses de HCl ou de HNO{sub 3} et d'alcools (methanol, ethanol, n-butanol), les R{sub f} des elements 90 a 96 ont ete determines. Certaines conclusions relatives a leur complexation par les ions Cl{sup -} et NO{sub 3}{sup -} ont pu en etre deduites. 3) - Nous avons elabore une technique d'electrophorese sur membrane d'acetate de cellulose afin de separer les especes chargees formees par les elements 90 a 96 dans des solutions HCl et HNO{sub 3} 1 a 12 M. Les courbes de mobilite ont ete tracees. Il decoule de nos resultats que la tendance des elements consideres a former des complexes anioniques s'etablit dans l'ordre des potentiels ioniques, lorsqu'ils sont a l'etat tetravalent; cet ordre est inverse lorsqu'ils sont a la valence III. Les ions Cl{sup -} sont moins complexants que les ions NO{sub 3}{sup -} vis-a-vis de ces elements dans leur etat d'oxydation III et IV, mais on observe le phenomene inverse pour U{sup VI} et Pu{sup VI}. Enfin, la complexation des cations Pu{sup 4+} et PuO{sub 2}{sup 2+} par NO{sub 3}{sup -} suit l'ordre des potentiels ioniques mais a lieu dans l'ordre inverse s'il s'agit d'ions Cl{sup -}. 4) - Diverses applications analytiques sont envisagees: separation les uns des autres des divers elements consideres et separation des etats de valence de Np et de Pu. (auteur)

  4. Study of cis- and trans-uranium elements by paper chromatography and electrophoresis; Contribution a l'etude des elements cis- et trans-uraniens par chromatographie sur papier et electrophorese

    Energy Technology Data Exchange (ETDEWEB)

    Clanet, F. [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-01-01

    'electrophorese, en chimie minerale, a ete etendu aux elements 90 a 96 en milieux HCl et HNO{sub 3}. Les resultats obtenus portent sur les points suivants: 1) - Caracterisation des etats de valence de Np et de Pu a l'aide de reactions colorees sur les chromatogrammes et les electrophoregrammes. L'alizarine, l'arsenazo-I et le thorin-I permettent de caracteriser la valence IV, tandis que le diphenylcarbazide est specifique de l'etat hexavalent. 2) - Chromatographie sur papier: en utilisant comme eluants des melanges a parts egales de solutions aqueuses de HCl ou de HNO{sub 3} et d'alcools (methanol, ethanol, n-butanol), les R{sub f} des elements 90 a 96 ont ete determines. Certaines conclusions relatives a leur complexation par les ions Cl{sup -} et NO{sub 3}{sup -} ont pu en etre deduites. 3) - Nous avons elabore une technique d'electrophorese sur membrane d'acetate de cellulose afin de separer les especes chargees formees par les elements 90 a 96 dans des solutions HCl et HNO{sub 3} 1 a 12 M. Les courbes de mobilite ont ete tracees. Il decoule de nos resultats que la tendance des elements consideres a former des complexes anioniques s'etablit dans l'ordre des potentiels ioniques, lorsqu'ils sont a l'etat tetravalent; cet ordre est inverse lorsqu'ils sont a la valence III. Les ions Cl{sup -} sont moins complexants que les ions NO{sub 3}{sup -} vis-a-vis de ces elements dans leur etat d'oxydation III et IV, mais on observe le phenomene inverse pour U{sup VI} et Pu{sup VI}. Enfin, la complexation des cations Pu{sup 4+} et PuO{sub 2}{sup 2+} par NO{sub 3}{sup -} suit l'ordre des potentiels ioniques mais a lieu dans l'ordre inverse s'il s'agit d'ions Cl{sup -}. 4) - Diverses applications analytiques sont envisagees: separation les uns des autres des divers elements consideres et separation des etats de valence de Np et de Pu. (auteur)

  5. Study of the strategies and controls of fuel cell systems associated with traction; Etude des strategies et des structures de commande pour le pilotage des systemes energetiques a Pile a Combustible (PAC) destines a la traction

    Energy Technology Data Exchange (ETDEWEB)

    Lachaize, J.

    2004-09-15

    This work falls into project COPPACE (Contribution to the Control of Embedded Fuel cell) carried out by ALSTOM in partnership with the LEEI-INPT and the CEA and supported by the ADEME. The study deals with the modelling and the control of a Fuel Cell system (flow, pressure, temperature) and the definition of the control laws for the static inverters associated with the traction of power train. We develop then a strategy of management of energy by taking into account the criteria of the hydrogen consumption or energy stored in the ultracaps. Each step is verified by total simulation according to a specific profile of mission and a precise model of fuel cells which has been simplified to reduce the computing time. The control of this system is defined by a separate treatment of the components, to finalize the total function objective. The results of simulations show that the system can follow the requested power while controlling the critical elements. (author)

  6. Species-and stage-specific differences in trace element tissue concentrations in amphibians: implications for the disposal of coal-combustion wastes

    International Nuclear Information System (INIS)

    Roe, John H.; Hopkins, William A.; Jackson, Brian P.

    2005-01-01

    Information on species-and stage-specific patterns of contaminant accumulation is generally lacking for amphibians, yet such information could provide valuable knowledge on how amphibians interact with contaminants. We assessed concentrations of As, Cd, Cu, Ni, Pb, Se, Sr, and Zn in whole bodies of larval, recently metamorphosed, and adult life stages in Bufo terrestris and Rana sphenocephala from a site that currently receives coal combustion waste (CCW) discharge, a site where CCW was formerly discharged that has undergone natural attenuation for 30 years, and a nearby reference site. For the majority of elements (As, Cd, Cu, Ni, Pb, Zn), concentrations were highest in larvae, but Se and Sr concentrations remained elevated in later life stages, likely because these elements are S and Ca analogs, respectively, and are thus retained throughout structural changes during metamorphosis. Element concentrations were generally higher in B. terrestris than in R. sphenocephala. Concentrations of As, Se, and Sr were up to 11-35 times higher in metamorphs emigrating from CCW-polluted wetlands compared to unpolluted wetlands, suggesting metamorphosed amphibians can transport trace elements from aquatic disposal basins to nearby uncontaminated terrestrial habitats. In addition, anurans utilizing naturally revegetated sites up to 30 years after CCW disposal ceases are exposed to trace elements, although to a lesser degree than sites where CCW is currently discharged. - Results suggest that metamorphosed amphibians can transport trace elements from aquatic disposal basins to non-contaminated habitats

  7. Species-and stage-specific differences in trace element tissue concentrations in amphibians: implications for the disposal of coal-combustion wastes

    Energy Technology Data Exchange (ETDEWEB)

    Roe, John H. [University of Georgia, Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802 (United States); Hopkins, William A. [University of Georgia, Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802 (United States)]. E-mail: hopkins@srel.edu; Jackson, Brian P. [University of Georgia, Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802 (United States)

    2005-07-15

    Information on species-and stage-specific patterns of contaminant accumulation is generally lacking for amphibians, yet such information could provide valuable knowledge on how amphibians interact with contaminants. We assessed concentrations of As, Cd, Cu, Ni, Pb, Se, Sr, and Zn in whole bodies of larval, recently metamorphosed, and adult life stages in Bufo terrestris and Rana sphenocephala from a site that currently receives coal combustion waste (CCW) discharge, a site where CCW was formerly discharged that has undergone natural attenuation for 30 years, and a nearby reference site. For the majority of elements (As, Cd, Cu, Ni, Pb, Zn), concentrations were highest in larvae, but Se and Sr concentrations remained elevated in later life stages, likely because these elements are S and Ca analogs, respectively, and are thus retained throughout structural changes during metamorphosis. Element concentrations were generally higher in B. terrestris than in R. sphenocephala. Concentrations of As, Se, and Sr were up to 11-35 times higher in metamorphs emigrating from CCW-polluted wetlands compared to unpolluted wetlands, suggesting metamorphosed amphibians can transport trace elements from aquatic disposal basins to nearby uncontaminated terrestrial habitats. In addition, anurans utilizing naturally revegetated sites up to 30 years after CCW disposal ceases are exposed to trace elements, although to a lesser degree than sites where CCW is currently discharged. - Results suggest that metamorphosed amphibians can transport trace elements from aquatic disposal basins to non-contaminated habitats.

  8. Boiler using combustible fluid

    Science.gov (United States)

    Baumgartner, H.; Meier, J.G.

    1974-07-03

    A fluid fuel boiler is described comprising a combustion chamber, a cover on the combustion chamber having an opening for introducing a combustion-supporting gaseous fluid through said openings, means to impart rotation to the gaseous fluid about an axis of the combustion chamber, a burner for introducing a fluid fuel into the chamber mixed with the gaseous fluid for combustion thereof, the cover having a generally frustro-conical configuration diverging from the opening toward the interior of the chamber at an angle of between 15/sup 0/ and 55/sup 0/; means defining said combustion chamber having means defining a plurality of axial hot gas flow paths from a downstream portion of the combustion chamber to flow hot gases into an upstream portion of the combustion chamber, and means for diverting some of the hot gas flow along paths in a direction circumferentially of the combustion chamber, with the latter paths being immersed in the water flow path thereby to improve heat transfer and terminating in a gas outlet, the combustion chamber comprising at least one modular element, joined axially to the frustro-conical cover and coaxial therewith. The modular element comprises an inner ring and means of defining the circumferential, radial, and spiral flow paths of the hot gases.

  9. Multi-Dimensional Modeling of Combustion and Pollutants Formation of New Technology Light Duty Diesel Engines Modélisation multidimensionnelle de la combustion et de la formation des polluants dans les nouveaux moteurs diesel automobiles

    Directory of Open Access Journals (Sweden)

    Belardini P.

    2006-12-01

    Full Text Available In the present paper some results, obtained by the use of modern numerical CFD tools, are presented. In particular, starting from the experimental characterization of a common rail DI Diesel engine, the empirical constants of the different submodels were tuned to obtain satisfactory results in some key test conditions. The main constraints of numerical models, to obtain a right scaling of pollutants predictions in the different test cases are analyzed. The numerical analysis demonstrates that the numerical CFD tools, at their stage of development, can help the engine designers to define the more promising strategies to obtain tailpipe emission control of common rail Diesel DI engines. Dans cet article, nous présentons les résultats obtenus en utilisant des outils de simulation de la mécanique des fluides numérique (CFD. À partir de résultats expérimentaux issus de la caractérisation d'un moteur Diesel common rail, les constantes empiriques de divers modèles ont été ajustées afin d'obtenir des résultats satisfaisants pour des cas tests représentatifs. Les principales contraintes des modèles numériques pour obtenir une bonne précision dans les différents cas d'études sont ici analysées. Cette analyse numérique montre que la CFD permet déjà, au stade de développement atteint, d'aider les ingénieurs à définir les stratégies les plus prometteuses pour maîtriser les émissions à l'échappement des moteurs Diesel à injection common rail.

  10. Instruments used to measure or check {alpha}, {beta}, {gamma} activity and neutron emission in the course of processing ore or irradiated fuel; Appareils de mesure ou de controle {alpha}, {beta}, {gamma}, n, des circuits des usines de traitement du minerai ou du combustible irradie

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, A; Brunet, M; Kermagoret, M; Labeyrie, J; Roux, G; Vasseur, J; Weil, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-01

    One of the methods checking ores in the course of treatment is the rapid quantitative determination of thorium. This measurement is carried out by means of a scintillation instrument which shows the {beta} and {alpha} coincidences of ThC and ThC'. The treatment of irradiated fuel is accompanied by a large number of radioactive checks relative to the performance of the fixation and elution operations of uranium in the ion exchangers, to the concentration of radioactivity of effluent sent from the plant into watercourses. The operations of fixation and elution of the uranium are checked automatically by an instrument which takes a sample of 5 cm{sup 3} of solution, evaporates it and measures its activity every 10 or 20 minutes. Plutonium concentrations are measured: - in the presence of strong {beta} {gamma} activities, by means of rotating cylinder detectors; - in the presence of weak {beta} {gamma} activities, by means of {alpha} detectors scanning a constant level liquid surface; - by means of fission chambers relatively insensitive to {gamma}. Fission product concentrations are measured by chambers, counters or scintillators, according to the amount of {gamma} activity present. Finally, the activity of effluent to be emptied into watercourses is checked by means of a scintillation instrument, which measures the {alpha} activity on the one hand, and on the other hand the {beta} {gamma} activity of residue from a 100 cm{sup 3} sample taken and evaporated in 20 minutes. (author) [French] Parmi les controles relatifs au minerai en cours de traitement, figure le dosage rapide de thorium. Cette mesure est realisee au moyen d'un appareillage a scintillation qui met en evidence la coincidence des emissions {beta} et {alpha} du ThC et du ThC'. Le traitement des combustibles irradies s'accompagne d'un grand nombre de controles radioactifs portant sur le fonctionnement des operations de fixation et d'elution de l'uranium dans les echangeurs d'ions, sur la concentration du

  11. Visualisation of Gasoline and Exhaust Gases Distribution in a 4-Valve Si Engine; Effects of Stratification on Combustion and Pollutants Visualisation de la répartition du carburant et des gaz brûlés dans un moteur à 4 soupapes à allumage commandé ; effet de la stratification sur la combustion et les polluants

    Directory of Open Access Journals (Sweden)

    Deschamps B.

    2006-12-01

    des dégagements d'énergie et des émissions de polluants très distincts. Le niveau de tumbleet l'emplacement de l'étincelle sont aussi modifiés. L'observation de la stratification telle qu'elle est réellement dans le moteur constitue un moyen pertinent pour expliquer ses performances. Les paramètres permettant d'optimiser les niveaux de NOx et d'HC peuvent en être déduits, de même que l'efficacité des stratégies de recirculation et d'injection du carburant. Les résultats des visualisations ont été confirmés par des mesures obtenues dans un moteur monocylindre muni d'une culasse conventionnelle avec la même géométrie de chambre de combustion.

  12. 3d Simulation of Di Diesel Combustion and Pollutant Formation Using a Two-Component Reference Fuel Simulation 3D de la combustion et de la formation des polluants dans un moteur Diesel à injection directe en utilisant un carburant de référence à deux composants

    Directory of Open Access Journals (Sweden)

    Barths H.

    2006-12-01

    reference fuels. The contributions of the different reaction paths (thermal, prompt, nitrous, and reburn to the NO formation are shown. Finally, the importance of the mixing process for the prediction of soot emissions is discussed. En séparant calculs aérodynamiques et calculs chimiques, le modèle instationnaire de flamelet permet d'introduire des mécanismes chimiques complets qui comprennent plusieurs centaines de réactions. Ceci est indispensable pour décrire les différents processus qui ont lieu dans un moteur Diesel à injection directe (ID tels que l'auto-inflammation, la fin de la phase de prémélange partiel, la transition vers une combustion diffusive et la formation de polluants tels que les NOx et les suies. Il n'est pas nécessaire de simplifier les taux de réactions hautement non linéaires, d'autre part, la structure complète du processus de combustion est conservée. En utilisant le modèle de type Representative Interaction Flamelet (RIF, l'ensemble monodimensionnel instationnaire d'équations différentielles aux dérivées partielles est résolu en interaction avec le code CFD 3D. La solution ainsi obtenue est couplée avec les flux gazeux et le champ de mélange par l'intermédiaire de plusieurs paramètres dépendant du temps (l'enthalpie, la pression, le taux scalaire de dissipation. En retour, le modèle de flamelet fournit les concentrations moyennes des espèces chimiques, qui sont ensuite exploitées par le code CFD 3D pour calculer les champs de températures et les densités. La densité est nécessaire au code CFD 3D pour déterminer les flux turbulents et le champ de mélange. La formation des polluants est déterminée expérimentalement dans un moteur Diesel Volkswagen DI 1900. Le moteur est alimenté avec du gazole et deux carburants de référence. Un des carburants de référence est du n-décane pur. Le second est un carburant bicomposant formé de 70 % (du volume liquide de n-décane et de 30 % d'alpha-méthylnaphtalène (Idea

  13. Species- and stage-specific differences in trace element tissue concentrations in amphibians: implications for the disposal of coal-combustion wastes

    Energy Technology Data Exchange (ETDEWEB)

    Roe, J.H.; Hopkins, W.A.; Jackson, B.P. [University of Georgia, Aiken, SC (US)

    2005-07-01

    Information on species- and stage-specific patterns of contaminant accumulation is generally lacking for amphibians, yet such information could provide valuable knowledge on how amphibians interact with contaminants. We assessed concentrations of As, Cd, Cu, Ni, Pb, Se, Sr, and Zn in whole bodies of larval, recently metamorphosed, and adult life stages in Bufo terrestris and Rana sphenocephala from a site that currently receives coal combustion waste (CCW) discharge, a site where CCW was formerly discharged that has undergone natural attenuation for 30 years, and a nearby reference site. For the majority of elements (As, Cd, Cu, Ni, Pb, Zn), concentrations were highest in larvae, but Se and Sr concentrations remained elevated in later life stages, likely because these elements are S and Ca analogs, respectively, and are thus retained throughout structural changes during metamorphosis. Element concentrations were generally higher in B. terrestris than in R. sphenocephala. Concentrations of As, Se, and Sr were up to 11-35 times higher in metamorphs emigrating from CCW-polluted wetlands compared to unpolluted wetlands, suggesting metamorphosed amphibians can transport trace elements from aquatic disposal basins to nearby uncontaminated terrestrial habitats. In addition, anurans utilizing naturally revegetated sites up to 30 years after CCW disposal ceases are exposed to trace elements, although to a lesser degree than sites where CCW is currently discharged.

  14. Contribution to the study of nuclear fuel materials with a metallic uranium base; Contribution a l'etude des materiaux combustibles nucleaires a base d'uranium metallique

    Energy Technology Data Exchange (ETDEWEB)

    Englander, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-11-15

    In a power reactor destined to supply industrially recoverable thermal energy, the most economical source of heat still consists of natural metallic uranium. However, the nuclear fuel material, most often employed in the form of rods of 20 to 40 mm diameter, is subjected to a series of stresses which lead to irreversible distortions usually incompatible with the substructure of the reactor. As a result the fuel material must possess at the outset a certain number of qualities which must be determined. Investigations have therefore been carried out, first on the technological characters peculiar to each of the three allotropic phases of pure uranium metal, and on their interactions on the stabilisation of the material which consists of either cast uranium or uranium pile-treated in the {gamma} phase. (author) [French] Dans un reacteur de puissance destine a fournir de l'energie thermique industriellement recuperable, la source de chaleur la plus economique reste constituee par de l'uranium metallique naturel. Or, le materiau combustible nucleaire, employe le plus souvent sous forme de barreaux de 20 a 40 mm de diametre, se trouve soumis a un ensemble de contraintes qui provoque des deformations irreversibles, le plus souvent incompatibles avec l'infrastructure du reacteur. Par consequent, le materiau combustible doit presenter a l'origine un certain nombre de qualites qu'il est necessaire de determiner. Aussi a-t-on d'abord etudie les caracteres technologiques propres a chacune des trois phases allotropiques de l'uranium-metal pur et leurs interactions sur la stabilisation du materiau constitue soit par de l'uranium coule, soit par de l'uranium traite en pile en phase {gamma}. (auteur)

  15. Determination of non-metallic elements in actinide complexes by oxygen flask combustion (OFC): chlorine and fluorine

    International Nuclear Information System (INIS)

    Ruikar, P.B.; Nagar, M.S.; Subramanian, M.S.

    1989-01-01

    The oxygen flask combustion followed by ion selective electrode measurement has been found to be the most suitable from the point of view of elegance and simplicity for the determination of chlorine and fluorine in actinide complexes. The method has been found to be particularly suitable for glove box adaptation. This report describes the determination of chlorine and fluorine in several uranium complexes, some plutonium complexes and organic analytical standards by this method. The precision and accuracy of the measurements in the milligram level has been found to be quite satisfactory. (author). 16 refs., 11 tabs

  16. Proposal of a numerical modeling of reactive flows in combustion chambers of turbojet engines; Proposition d`une modelisation numerique des ecoulements reactifs dans les foyers de turboreacteurs

    Energy Technology Data Exchange (ETDEWEB)

    Ravet, F. [Rouen Univ., 76 - Mont-Saint-Aignan (France)]|[SNECMA, 77 - Moissy-Cramayel (France); Baudoin, Ch.; Schultz, J.L. [SNECMA, 77 - Moissy-Cramayel (France)

    1996-12-31

    Simplifying hypotheses are required when combustion and aerodynamic phenomena are considered simultaneously. In this paper, a turbulent combustion model is proposed, in which the combustion chemistry is reduced to a single reaction. In this way, only two variables are needed to describe the problem and combustion can be characterized by the consumption of one of the two reactive species. In a first step, the instantaneous consumption rate is obtained using the Lagrangian form of the mass fraction equation of the species under consideration, and by considering the equilibrium state only. This state is determined in order to preserve the consistency with results that should be obtained using a complete kinetics scheme. In a second step, the average rate is determined using the instantaneous consumption term and a probabilistic density function. This model was tested on various configurations and in particular on an experimental main chamber and on a reheating chamber. Results indicate that this model could be used to predict temperature levels inside these combustion chambers. Other applications, like the prediction of pollutant species emission can be considered. (J.S.) 12 refs.

  17. Experimental study of the aluminum droplet combustion under forced convection. Influence of the gaseous atmosphere; Etude experimentale de la combustion des gouttes d'aluminium en convection forcee. Influence de l'atmosphere gazeuse

    Energy Technology Data Exchange (ETDEWEB)

    Sarou-Kanian, V.

    2003-12-15

    Because of its high energetic power, the combustion of aluminum particles in solid propellant rocket motors improves the efficiency of heavy-lift launcher as Ariane 5. Aluminum particles burn in a gaseous atmosphere essentially composed of H{sub 2}O, CO{sub 2}, N{sub 2}, HCl, H{sub 2}, and CO, at high pressure (P=60-70 atm) and high temperature (T>3000 K). In the present work, we have been particularly interested in the influence of the gaseous atmosphere on the different burning processes both in the gas-phase and at the aluminum droplet surface. An experimental set-up was developed in order to describe precisely, thanks to several analysis techniques (high-speed camera, pyrometry, spectrometry, SEM, nuclear activation) the combustion of aerodynamically levitated millimetric aluminum droplets in gas mixtures with compositions close to the propellant ones (H{sub 2}O, CO{sub 2}, N{sub 2}). The main result is that each species plays a different role in the aluminum combustion. The water vapor has the biggest influence in the gas-phase process due to the production of hydrogen facilitating the heat and mass diffusion between the flame and the droplet. Nitrogen is essentially acting in surface reactions with the formation of aluminum nitride (AlN) and oxynitride (AlON) which may completely cover the droplet and stop the gas-phase combustion. Carbon dioxide has a double effect. On the one hand, CO{sub 2} burns in the flame, but it is less efficient than H{sub 2}O because the heat and mass transfer properties are poorer for CO than for H{sub 2}. On the other hand, a carbon dissolution phenomenon occurs in the aluminum droplet during burning which may reach saturation (20-25% molar) and involves a carbon rejection at the surface leading to the end of the gas-phase combustion. (author)

  18. Fuel elements (uranium clad with zirconium) produced by co-extrusion; Les elements combustibles uranium gaine de zirconium obtenus par coextrusion

    Energy Technology Data Exchange (ETDEWEB)

    Montagne, R.; Winogradzki, A.; Sauve, C.; Buffet, J. [Commissariat a l' energie atomique et aux energies alternatives - CEA, Departement de Metallurgie et de Chimie Appliquee (France)

    1959-07-01

    In this paper a description is given of a process for making fuel elements for atomic reactors. Contact of the most intimate possible kind is achieved between the fuel and the sheath by the simultaneous extrusion of the two elements. Genuine welding between the two metals is thus effected. This can be subsequently improved by a heat-treatment which causes diffusion. Tests made on these co-extruded elements are described in the paper. Reprint of a paper published in Revue de Metallurgie, LV, no. 11, 1958.

  19. Determination of the Effectiveness of Control Rods in the VVER Reactor Fuel Assemblies; Determination de l'Efficacite des Barres de Reglage dans les Ensembles Combustibles du reacteur VVER; Opredelenie ehffektivnosti reguliruyushchikh sterzhnej v sborkakh reaktora VVEHR; Determinacion de la Eficacia de las Barras de Control en los Conjuntos de Elementos Combustibles del Reactor VVER

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, V. N.; Lunin, G. L.; Komissarov, L. V.; Kamyshan, A. N.; Halizev, V. I.; Andrianov, G. Ja.; Voznesenskij, V. A.; Kuz' micheva, V. A.; Lebedev, V. I. [Ordena Lenina Institut Atomnoj Energii Im. I.V. Kurchatova, Moskva, SSSR (Russian Federation)

    1964-06-15

    The paper describes experiments done in homogeneous mock-ups of the fuel assemblies from the VVER Reactor (at one level of enrichment) to determine the effectiveness of absorbing systems comprising shim fuel assemblies or water cavities and of absorbing rods clad in jackets made of differing materials. The paper also gives data on some experiments that have been done in mock-ups of assemblies with differing levels of enrichment. These experiments make it possible to verify the methods used in calculation and to evaluate the prospects of using them for heterogeneous reactors. (author) [French] Le memoire decrit les experiences qui ont ete faites pour determiner l 'efficacite des absorbants contenus dans les barres de compensation, l'effet cavitaire et l 'efficacite des absorbants gaines de materiaux divers, au moyen d'assemblages homogenes de cartouches de combustible du reacteur VVER (reacteur de puissance ralenti et refroidi a l 'eau ayant le meme taux d'enrichissement. On y trouve en outre des donnees sur certaines experiences executees a l 'aide d'assemblages de cartouches de combustible taux d'enrichissement differents. Ces travaux permettent de verifier la methode de calcul et d'evaluer ses possibilites d'application aux reacteurs non homogenes. (author) [Spanish] Se describen en la memoria experimentos para determinar la eficacia de los materiales absorbentes contenidos en las barras de compensacion, el efecto de cavitacion y la eficacia de los materiales absorbentes revestidos de diversos materiales, realizados con ayuda de los conjuntos homogeneos de elementos combustibles del reactor VVER (reactor de potencia moderado y refrigerado por agua) con un solo grado de enriquecimiento. Ademas, se exponen datos sobre los experimentos efectuados con ayuda de conjuntos de grados de enriquecimientos; variados. Tales experimentos permiten verificar el metodo de calculo teorico, utilizad o y evaluar la posibilidad de aplicarlo a los reactores no homogeneos. (author

  20. Prevention of trace and major element leaching from coal combustion products by hydrothermally-treated coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Adnadjevic, B.; Popovic, A.; Mikasinovic, B. [University of Belgrade, Belgrade (Serbia). Dept. of Chemistry

    2009-07-01

    The most important structural components of coal ash obtained by coal combustion in 'Nikola Tesla A' power plant located near Belgrade (Serbia) are amorphous alumosilicate, alpha-quartz, and mullite. The phase composition of coal ash can be altered to obtain zeolite type NaA that crystallizes in a narrow crystallization field (SiO{sub 2}/Al{sub 2}O{sub 3}; Na{sub 2}O/SiO{sub 2}; H{sub 2}O/Na{sub 2}O ratios). Basic properties (crystallization degree, chemical composition, the energy of activation) of obtained zeolites were established. Coal ash extracts treated with obtained ion-exchange material showed that zeolites obtained from coal ash were able to reduce the amounts of iron, chromium, nickel, zinc, copper, lead, and manganese in ash extracts, thus proving its potential in preventing pollution from dump effluent waters.

  1. Retrofit MHB Hamm. Process-related optimization of the combustion air system MHB Hamm; Retrofit MHB Hamm. Prozess- und verfahrenstechnische Optimierung des Verbrennungsluftsystems MHB Hamm

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, Frank [SC Schumacher Consulting handelnd fuer Xervon Energy GmbH, Ritterhude (Germany); Lindke, Carsten [MHB Hamm Betriebsfuehrungsgesellschaft mbH, Hamm (Germany); Auel, Werner [Xervon Energy GmbH, Duisburg (Germany)

    2012-11-01

    The authors of the contribution under consideration report on a process-related optimization of the combustion air system of the waste incinerator Hamm. Subsequently to the historical aspects of this waste incinerator and the development of its calorific values, the authors describe the tender Retrofit, its implementation as well as the first practical experiences.

  2. Application of resistivity measurements to research on structural elements in the Nord-Limousin (France) uraniferous basin (1960); Application des mesures de resistivite a la recherche des elements structuraux dans le bassin uranifere du Nord-Limousin (France) (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Sarcia, J A; Bonnet, J; Combe, R [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The authors discuss the difficulties encountered in the exploration of a typical deposit in the Nord-Limousin, using the resistivity measurement method. In the zone in question the over-thrust was very variable and difficult to predict. The uraniferous deposits had two types of aspect, the passage from one to the other being often very sudden: long thin veins without gangue; short and thick lens-shape deposits which were strongly contaminated by clay towards their edges. After several unsatisfactory attempts, the device known as the 'rectangular map' was adopted and gave an acceptable structural representation rapidly and cheaply. For the placing of the probes however, methods are required which are more refined and sensitive. It is in any case useless to expect to obtain a satisfactory representation and a sufficient accuracy using a single technique; especially in the region under consideration. (author) [French] Les auteurs exposent les difficultes rencontrees pour l'exploration, par la methode des mesures de resistivite, d'un gisement type du Nord-Limousin: il s'agissait d'une zone a recouvrement tres variable et difficilement previsible. Les occurences uraniferes y affectaient deux facies passant brutalement de l'un a l'autre: longs filonnets minces et sans gangue; lentilles courtes et puissantes avec alteration argileuses tres etendue aux epontes. Apres plusieurs essais peu satisfaisants, le dispositif dit 'carte des rectangles' a ete adopte pour obtenir rapidement et a bon compte un schema structural suffisant. Mais des methodes plus fines et plus sensibles sont necessaires pour guider l'implantation des sondages. Il est d'ailleurs vain d'esperer trouver a la fois la representativite d'ensemble et la precision, dans l'utilisation d'une seule technique, surtout dans la region envisagee. (auteur)

  3. Burners. The decrease of nitrogen oxides in combustion process: the 2 nd generation GR LONOxFLAM burner; Les bruleurs, la reduction des oxydes d`azote dans la combustion: bruleur GR LONOxFLAM de 2. generation

    Energy Technology Data Exchange (ETDEWEB)

    Gauthier, J.C. [EGCI Pillard, 13 - Marseille (France)

    1997-12-31

    The Pillard company has developed, in cooperation with GDF (the French national gas utility), the GR-LONOxFLAM burner concept for reducing NOx emission levels and solid combustion products. The concept consists, for gaseous fuels, in the combination of an internal recirculation and a gas staging process; for liquid fuels, a separated flame process and air staging are combined. These concepts allow for an important reduction in NOx and non-burned residues, even with standard-size burners

  4. La puissance prescriptive des guides à Paris The prescriptive power of tour guides in Paris. Standardizing elements of tourism ?

    Directory of Open Access Journals (Sweden)

    Gwendal Simon

    2008-10-01

    Full Text Available Les « guide-interprètes » constituent des médiateurs entre les touristes et les espaces. Incarnant une présence physique en mesure d’aider les touristes en les informant sur la ville, ils opèrent comme prescripteurs de choses à voir et à faire. S’ils officient très diversement selon les touristes qu’ils accompagnent, ils exercent toujours leur pratique dans une logique de production de discours sur la ville. À Paris, la dimension muséale et patrimoniale constitue depuis longtemps le socle de l’attractivité touristique, qui continue de capitaliser sur des imaginaires et des pratiques liés à la grande ville d’Art et d’Histoire. Face à la constitution de ce référentiel dominant qui opère comme une force d’ « imposition », les guide-interprètes tentent néanmoins de décentrer le regard par des prescriptions délestées des symboles. C’est cette « tension » entre cet ensemble de références touristiques « à voir » et le souci de montrer la ville dans sa pluralité que nous analysons. Ces éléments nourrissent la réflexion actuelle sur les formes polarisées du tourisme à Paris et l’importance de la production de référents urbains plus contemporains que promeut la municipalité.Tour guides are mediators between tourists and spaces. As they embody a physical presence helping tourists and informing them about the city, they also act as prescribers, laying down what is supposed to be seen and to be done. If their recommendations depend on the tourists they travel with, they always mean to produce a discourse on the city. Paris’ museums and heritage have long since been two cornerstones of her enduring appeal. Confronted with this phenomenon, which tends to standardize the way of visiting a city, tour guides try to free their guidelines of symbolic references. This contribution focuses on the tension between must-see tourist references and the desire to show the city in all its diversity. These

  5. The combustion system of the MAN 20V35/44G gas engine; Das Brennverfahren des Gasmotors 20V35/44G von MAN

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Markus; Auer, Matthias; Stiesch, Gunnar [MAN Diesel and Turbo SE, Augsburg (Germany)

    2013-04-15

    The new gas engine 20V35/44G by MAN Diesel and Turbo SE has a power output of 10.6 MW. The high effective efficiency level of 48.4 % as well as numerous technical innovations allow an environment-friendly, economical and reliable engine operation. Key to achieve this is the combustion system, which has been optimised during advanced engineering by means of modern simulation tools and extensive single-cylinder tests. (orig.)

  6. Study of polyoxide catalysts of methane combustion on Mn, Cu, Ni, rare earth elements, alkaline earth elements base by the X-ray fluorescence analysis method

    International Nuclear Information System (INIS)

    Grigor'eva, V.P.; Popova, N.M.; Zheksenbaeva, Z.T.; Sass, A.S.; Salakhova, R.Kh.; Dosumov, K.D.

    2002-01-01

    The results of X-ray fluorescence analysis of polyoxide catalysts on of Mn, Cu, Ni, rare earth elements, alkaline earth elements base supported on 2 % Ce/θ-Al 2 O 3 are presented. This polyoxide catalysts are using for deep methane oxidation. DRON-4-7 X-ray diffractometers was applied for the analysis. It was found, that oxides in Ni-Cu-Cr catalysts after long time heating up to 1200 deg. C have been interacted with catalyst supports with Ni(Cu)Al 2 O 3 aluminates formation and due to its decomposition transformation degree of CH 4 to CO 2 are reduced. Activity of MnBaSrCeLa catalysts after heating up to 1200 deg. C does not changed

  7. Formation and destruction mechanisms of nitrogen oxides during coal combustion in circulating fluidized beds; Mecanismes de formation et de destruction des oxydes d`azote lors de la combustion du charbon en lit fluidise circulant

    Energy Technology Data Exchange (ETDEWEB)

    Borrel, G.; Lecuyer, I. [Universite du Haut-Rhin, 68 - Mulhouse (France)

    1997-01-01

    Formation and reduction of nitrogen oxides (NO and N{sub 2}O) during coal combustion in a circulating fluidized bed (CFBC) are very complicated and yet badly known. The aim of the present study was to better characterize these phenomena on a small-sized experimental unit (reactor diameter: 5 cm), with the possibility to re-inject the solids in the bottom of the furnace, as in a real industrial unit. This should allow then to develop a numerical set of chemical reactions involving the nitrogen oxides. The experimental results showed that coal ash plays a great role in reducing nitrogen oxides, the determining parameter being the quantity of unburnt carbon remaining in the ash. The study then detailed the interaction between nitrogen oxides and de-volatilized (char) according to the temperature, NO{sub x} concentration and the mass of solid. In the absence of oxygen small quantities of char can very significantly reduce NO as well as N{sub 2}O. It was possible to establish destruction kinetics on these particles, and orders of reaction could be determined versus the NO{sub x} concentration and the char particle mass (heterogeneous phase chemical reactions). Then, the coal pyrolysis study enabled to identify the products released during coal devolatilization and thermogravimetric analyses displayed several successive weight losses due CO, CO{sub 2} and CH{sub 4} releases, during a linear temperature increase. Lastly coal combustion was studied in the small pilot with variable experimental conditions. Using the previous experimental was studied in the small pilot with variable experimental conditions. Using the previous experimental results, a model was developed to calculate NO{sub x} concentrations during the coal combustion and validated. The NO and N{sub 2}O contents calculated are thoroughly correlated with the experimental data whatever the injection carbon/oxygen ratio is. (author) 96 refs.

  8. Effects of alloying elements on the microstructure and fatigue properties of cast iron for internal combustion engine exhaust manifolds

    Science.gov (United States)

    Eisenmann, David J.

    In the design of exhaust manifolds for internal combustion engines the materials used must exhibit resistance to corrosion at high temperatures while maintaining a stable microstructure. Cast iron has been used for manifolds for many years by auto manufacturers due to a combination of suitable mechanical properties, low cost, and ease of casting. Over time cast iron is susceptible to microstructural changes, corrosion, and oxidation which can result in failure due to fatigue. This thesis seeks to answer the question: "Can observed microstructural changes and measured high temperature fatigue life in cast iron alloys be used to develop a predictive model for fatigue life?" the importance of this question lies in the fact that there is little data for the behavior of cast iron alloys at high temperature. For this study two different types of cast iron, 50HS and HSM will be examined. Of particular concern for the high Si+C cast irons (and Mo in the case of the HSM cast iron) are subsurface microstructural changes that result due to heat treatment including (1) decarburization, (2) ferrite formation, (3) graphitization, (4) internal oxidation of the Si, (5) high temperature fatigue resistance, and (6) creep potential. Initial results obtained include microstructure examination after being exposed to high temperatures, grain size, nodule size, and hardness measurements. The initial examinations concluded that both cast irons performed fairly similarly, although the microstructure of the HSM samples did show slightly better resistance to high temperature as compared to that of the 50HS. Follow on work involved high temperature fatigue testing of these two materials in order to better determine if the newer alloy, HSM is a better choice for exhaust manifolds. Correlations between fatigue performance and microstructure were made and discussed, with the results examined in light of current and proposed models for predicting fatigue performance based on computational methods

  9. Evaluation of turbulent transport and flame surface dissipation using direct numerical simulation of turbulent combustion; Evaluation des termes de transport et de dissipation de surface de flamme par simulation numerique directe de la combustion turbulente

    Energy Technology Data Exchange (ETDEWEB)

    Boughanem, H.

    1998-03-24

    The assumption of gradient transport for the mean reaction progress variable has a limited domain of validity in premixed turbulent combustion. The existence of two turbulent transport regimes, gradient and counter-gradient, is demonstrated in the present work using Direct Numerical Simulations (DNS) of plane flame configurations. The DNS data base describes the influence of the heat release factor, of the turbulence-to-flame velocity ratio, and of an external pressure gradient. The simulations reveal a strong correlation between the regime of turbulent transport and the turbulent flame speed and turbulent flame thickness. These effects re not well described by current turbulent combustion models. A conditional approach `fresh gases / burnt gases` is proposed to overcome these difficulties. Furthermore, he development of flame instabilities in turbulent configurations is also observed in the simulations. A criterion is derived that determines the domain of occurrence of these instabilities (Darrieus- Landau instabilities, Rayleigh- Taylor instabilities, thermo-diffusive instabilities). This criterion suggests that the domain of occurrence of flame instabilities is not limited to small Reynolds numbers. (author) 98 refs.

  10. Qualification des logiciels numériques. Application à un logiciel d'analyse de la combustion dans les moteurs à allumage commandé Qualification of Numerical Software. Application to a Software for Analysing Combustion in Spark-Ignition Engines

    Directory of Open Access Journals (Sweden)

    Vignes J.

    2006-11-01

    Full Text Available La simulation numérique est actuellement très utilisée pour étudier les systèmes physiques. Elle nécessite un programme de calcul scientifique constitué d'un modèle mathématique représentatif du problème étudié et des méthodes numériques de résolution associées. Elle fournit des résultats numériques censés représenter le phénomène physique. Pour pouvoir valider la simulation, il est absolument indispensable, d'une part, d'estimer la propagation des erreurs d'arrondi due à l'arithmétique approchée des ordinateurs et, d'autre part, d'évaluer l'influence des erreurs de données sur les résultats fournis. Nous présentons, dans cet article, le logiciel CADNA qui permet de valider les logiciels numériques. Nous l'appliquons à un logiciel de simulation d'analyse de la combustion dans les moteurs à allumage commandé et en montrons son efficacité. For analyzing physical phenomena, numerical simulation is used more and more frequently. Starting with a mathematical model describing the phenomenon being analyzed, this simulation consists in creating a scientific computing program expressing this model by implementing the numerical methods required for solving it. Simulation is considered to be valid when the results its provides are in agreement with the results issuing from experimenting with the phenomenon. However, to conclude in the possible validity of the simulation, the numerical results provided by the computer must be previously validated. Yet, these results contain a computing error resulting from the propagation of round-off errors caused by the floating-point arithmetic used by the computer. They also contain an error coming from the uncertainties concerning the data of the problem. Hence it is first indispensable to assess the influence of these errors. This article is made up of two parts. The first part concerns the validation of numerical software results. After making a brief review of the floating

  11. Solvent purification using a current of water vapour. A continuous process applicable to chemical plants treating irradiated fuels; Purification des solvants par entrainement a la vapeur d'eau. Procede continu applicable aux usines chimiques de traitement des combustibles irradies

    Energy Technology Data Exchange (ETDEWEB)

    Auchapt, P R; Sautray, R R; Girard, B R [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

    1964-07-01

    The pilot plant described in this report is intended for the continuous purification of the solvent used in the plutonium extraction plant at Marcoule, by separating the impurities (fission products). This physical separation is operated by carrying over in a water vapour stream. The contaminating products, only slightly volatile, remain in the form of the droplets and are separated; the vaporised solvent and the water vapour used are condensed and then separated. The originality of the installation resides in the system for pulverising the liquid and in the operating conditions: low working pressure and temperature. The systematic analysis of the various parameters (percentage of residue; flow, pressure and temperature ratios etc...) has shown their influence on the decontamination. The activity due to the zirconium-niobium is undetectable after treatment, and it is easy to obtain decontamination factors of 300 for the ruthenium. The, presence of uranium is favorable for the decontamination. As a conclusion, some extra-technical considerations are given concerning in particular the approximate cost price of the treated solvent per litre. (authors) [French] L'installation pilote decrite dans ce rapport est destinee a purifier, en continu, le solvant utilise a l'usine d'extraction du plutonium de Marcoule, en separant les impuretes (produits de fission). Cette separation physique est realisee par entrainement a la vapeur d'eau. Les produits contaminants, peu volatils, restant sous forme de gouttelettes, sont separes; le solvant vaporise ainsi que la vapeur d'entrainement sont condenses puis separes. L'originalite de l'installation reside dans le systeme de pulverisation du liquide et dans les conditions operatoires: faible pression et basse temperature de fonctionnement. L'analyse systematique des differents parametres (pourcentage de residus, rapport de debits, pression et temperature, etc...) a mis en evidence leur influence sur la decontamination. L'activite en

  12. Processing Th C{sub 2} - UC{sub 2} fuel extracted from high temperature reactors HTGCR; Etude du traitement des combustibles Th C{sub 2} - UC{sub 2} issus de reacteurs a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Derrien, C; Lessart, P; Pianezza, E; Verry, C; Villain, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    The object of this investigation is solubilisation head-end (from crushing and grinding phase to non included first purification phase) of pulverulent ({sup 233}U/{sup 232}Th)C{sub 2} (200 - 500 microns diameter) contained in a graphite matrix extracted from a 4.10{sup 13} n.cm{sup -2}.s{sup -1} thermalized neutrons average flux with an irradiation of 80000 MWjT{sup -1} HTGCR reactor. After having succinctly described different bibliographic processes we have chosen the burn - leach of reactor fuel and graphite matrix containing it. The technology of burner is original in nuclear field and still more by utilizing ultra-sounds to intensify burning reaction and to minimize the weight of unburnables. The mixture of ThO{sub 2}, U{sub 3}O{sub 8}, and fission products oxides is solubilized by boiling HNO{sub 3} 13 M + HF 0.05 M. This process is profit-learning in a thorium recuperation and reprocessing point of view. In the contrary-case it would be interesting to consider a dry-process which would permit to separate solid ThF{sub 4} from gaseous UF{sub 6}. (authors) [French] Cette etude a pour objet le traitement initial de mise en solution ou 'head-end' (allant de la phase broyag-concassage a la phase de premiere purification exclue) d'un combustible ({sup 233}U/{sup 232}Th)C{sub 2} pulverulent (de 200 a 500 {mu} de diametre) contenu dans une matrice de graphite issu d'un reacteur HTGCR surgenerateur a neutrons thermiques de flux moyen 4. l0{sup 13} n.cm{sup -2}.s{sup -1} et taux d'irradiation 80000 MWjT{sup -1}. Apres exposition succincte des differents procedes bibliographiques decrits, nous avons finalement choisi le traitement par combustion-attaque ('Burn-Leach') du combustible et de la matrice etanche graphite qui le contient. La technologie du bruleur est originale dans le domaine nucleaire d'autant qu'elle utilise les ultra-sons pour ameliorer le rendement de la reaction de combustion et reduire au minimum le poids des imbrules. Le melange ThO{sub 2}, U{sub 3}O

  13. Development of reduced kinetic schemes for the description of pollutants formation in combustion; Mise au point de schemas cinetiques reduits pour decrire la formation des polluants dans la combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ferrendier, M.

    1998-12-17

    The typical dimensions of details chemical-kinetic mechanisms proposed to describe combustion systems are too large for multi-dimensional computations applications. The objective of reduction methods is to construct low-dimensional schemes that can be incorporated in industrial codes. We consider here a new class of methods based on a mathematical analysis of the detailed chemical-kinetic mechanisms, and the identification of a low-dimensional manifold that describes the slow dynamics of the chemical system. The mathematical reduction methods considered in this work are the Intrinsic Low Dimensional Manifold (ILDM) method proposed by Maas and Pope (1992), and the Singular Perturbation (PS) method proposed by Duchene and Rouchon (1996). The domain of validity of the ILDM or PS reduced schemes is limited to a high temperature domain T {>=} T{sub c}. This result suggests that ignition is out of the domain of application of reduced mechanisms. In the case of a CO/H{sub 2}/N{sub 2}-air combustion system, and using a two-dimensional slow manifold, we find T{sub c} {approx} 750 K. We also find that for that particular system, 2 progress variables are sufficient for an accurate description of the structure and the velocity of a laminar premixed flame. In the case of a CH{sub 4}-air combustion system, and using a two-dimensional slow manifold, we find T{sub c}{approx}1500 K. We also find that 2 progress variables are insufficient for an accurate description of the structure and the velocity of a laminar premixed flame. The study of the different NO formation mechanisms show that the thermal NO mechanism (the Zeldovich mechanism) is dominant for premixed configurations with lean or stoichiometric conditions ({phi}){>=}1.2), and for non-premixed configurations at high temperatures and high pressures (T{sub air}{>=}1000 K, P {>=} 10 bars). Under these conditions, the MPKIVA sub model used to describe NO formation in the IFP version of the KIVA code performs reasonably well. An

  14. Aerodynamic study of the fluid flow in the channel of a reactor filled with internally and externally cooled fuel elements; Etude aerodynamique de l'ecoulement fluide dans un canal de reacteur charge en elements combustibles annulaires refroidis interieurement et exterieurement

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, J C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    A study is made of the problem of the flow-rate and pressure distributions along the length of two volumes, internal and external, bounded by a series of non-continuous annular elements placed along the channel axis. It is observed that the phenomenon can easily be represented by equations. The theoretical expressions observed are particularly simple when the distances between the elements are above a certain minimum value. The experimental work has made it possible to show that the theoretical formulation derived is valid with a very great accuracy. The experimental study has also been carried out in the case of a very small spacing between the elements. It has been possible to show in this case that the hypothesis made for deriving the theoretical expressions was perfectly justified. In the last part finally, we consider the practical problem of evaluating the pressure-drops between the ends of a series of annular elements. (author) [French] On etudie le probleme de la repartition des debits et des pressions le long des deux espaces, interne et externe, delimites par une succession d'elements annulaires non jointifs, disposes suivant l'axe d'un canal. On constate que le phenomene peut etre mis aisement en equation. Les relations theoriques obtenues prennent en particulier une forme simple lorsque les intervalles entre elements sont superieurs a une valeur minimum. L'etude experimentale a permis de constater que cette formulation theorique etablie etait alors valable avec une precision excellente. L'etude experimentale a ete egalement effectuee dans le cas de tres faibles intervalles entre elements consecutifs. On a pu alors verifier que l'hypothese adoptee dans l'etablissement des relations theoriques etait parfaitement justifiee. Dans un dernier chapitre enfin, nous abordons le point de vue pratique de l'evaluation des pertes de charge aux bornes d'un train d'elements annulaires. (auteur)

  15. Aerodynamic study of the fluid flow in the channel of a reactor filled with internally and externally cooled fuel elements; Etude aerodynamique de l'ecoulement fluide dans un canal de reacteur charge en elements combustibles annulaires refroidis interieurement et exterieurement

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, J.C. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    A study is made of the problem of the flow-rate and pressure distributions along the length of two volumes, internal and external, bounded by a series of non-continuous annular elements placed along the channel axis. It is observed that the phenomenon can easily be represented by equations. The theoretical expressions observed are particularly simple when the distances between the elements are above a certain minimum value. The experimental work has made it possible to show that the theoretical formulation derived is valid with a very great accuracy. The experimental study has also been carried out in the case of a very small spacing between the elements. It has been possible to show in this case that the hypothesis made for deriving the theoretical expressions was perfectly justified. In the last part finally, we consider the practical problem of evaluating the pressure-drops between the ends of a series of annular elements. (author) [French] On etudie le probleme de la repartition des debits et des pressions le long des deux espaces, interne et externe, delimites par une succession d'elements annulaires non jointifs, disposes suivant l'axe d'un canal. On constate que le phenomene peut etre mis aisement en equation. Les relations theoriques obtenues prennent en particulier une forme simple lorsque les intervalles entre elements sont superieurs a une valeur minimum. L'etude experimentale a permis de constater que cette formulation theorique etablie etait alors valable avec une precision excellente. L'etude experimentale a ete egalement effectuee dans le cas de tres faibles intervalles entre elements consecutifs. On a pu alors verifier que l'hypothese adoptee dans l'etablissement des relations theoriques etait parfaitement justifiee. Dans un dernier chapitre enfin, nous abordons le point de vue pratique de l'evaluation des pertes de charge aux bornes d'un train d'elements annulaires. (auteur)

  16. Use of trace elements as indicators for underground fluid circulations in karstic environment; Utilisation des elements en trace comme traceurs des circulations souterraines en milieu karstique (site du Lamalou, Herault)

    Energy Technology Data Exchange (ETDEWEB)

    Pane-Escribe, M B

    1995-06-29

    The geochemical study of the trace element behaviour in karstic groundwaters has been carried out over the experimental site of Lamalou (Herault, France). Routine measurements of the physico-chemical parameters and of the dissolved elements concentrations have been achieved during two hydrological cycles. Radon has been monitored by passive detectors and by automatic electronic probes. Trace elements (Sc, Ti, V, Cr, Ni, Cu, Zn, As Rb, Sr, Mo, Cd, Sb, Cs, Ba, Th, U) were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The first part of this work presents the methodologies employed with in particular the improvement of the analytical performances of ICP-MS for water samples analysis. The detection limit for each considered element has been determined. The short and long term reproducibility for the samples analysis has also been tested. The second part of this study presents the treatment and interpretation of the results. This analysis has pointed our the influence of the aquifer structure on the chemical elements distribution. The trace and major elements concentrations are effectively related to the fracturing state of the reservoir and allow to individualize the high transmissivity zones from zones with a lower transmissivity in this mono-lithological context, trace elements appear to be particularly efficient tracers for determining the water origin and circulation their spatial and temporal behaviour leads to identify three different origins for the water mineralization over the studied area: limestones, clays and external sources (rainfalls and occasional pollutions). (author). 154 refs.

  17. Numerical and experimental study of the influence of the operational parameters on the formation mechanisms of oxides of nitrogen during the combustion of mixtures of cellulosic and plastic materials; Etude experimentale et numerique de l'influence des parametres operatoires sur les mecanismes de formation des oxydes d'azote lors de la combustion de melanges de materiaux cellulosiques et plastiques

    Energy Technology Data Exchange (ETDEWEB)

    Andzi Barhe, T.

    2004-10-15

    The current thesis was performed within a collaboration between the Laboratoire de Combustion et de Detonique (LCD of the University of Poitiers) and the Laboratoire de Physique et de Chimie d'Environnement (LPCE) of the University of Ouagadougou. It was financed by Agency for Environment and Energy Management (ADEME). The principle object of this study is the optimisation of the combustion process during the incineration of waste. This optimisation is aimed at the reduction of the polluting emissions, principally CO and NO, during the incineration of cellulosic and plastic materials. It involves the analysis of the influence of the operational parameters on the polluting emissions and the control of reaction mechanisms of formation and reduction of these pollutants during the combustion process. Consequently, the study was performed in two parts: an experimental part and a numerical part. The experimental part was realised using a fixed bed counterflow reactor. This setup simulates the combustion within an industrial waste incinerator. The reactor allows the combustion of a vertical layer of waste mixture (wood, cardboard, PET, polyamide) to be followed. Three model mixtures representative of the makeup of household waste were studied in order to determine the influence of the composition of the waste on the emission of pollutants (CO and NO). The obtained results show that this parameter has a practically negligible influence within the tested parameter range. Consequently the formation of pollutants depends on the operating parameters - the equivalence ratio and the temperature. A numerical study of the influence of these parameters in order to show their impact on the mechanisms of pollutant formation and to determine the chemical mechanisms involved in the formation of oxides of nitrogen. The numerical study was performed with software developed at the LCD. This programme based on a detailed chemical model coupled to a simple physical model. It uses the

  18. Study of the behaviour of some heavy elements in solvents containing hydrogen fluoride; Etude du comportement de quelques elements lourds dans des solvants a base d'acide fluorhydrique

    Energy Technology Data Exchange (ETDEWEB)

    Tarnero, M [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-01-01

    The anhydrous liquid mixtures: dinitrogen tetroxide-hydrogen fluoride and antimony pentafluoride-hydrogen fluoride were studied as solvents for heavy elements interesting nuclear energy: uranium, thorium, zirconium and for some of their compounds. For N{sub 2}O{sub 4}-HF mixtures, electric conductivity measurements and liquid phase infrared spectra were also obtained. Uranium and zirconium tetrafluoride are much more soluble in N{sub 2}O{sub 4}-HF mixtures than in pure hydrogen fluoride. Uranium dissolved in these mixtures is pentavalent. In SbF{sub 5}-HF mixtures, uranium dissolves with hydrogen evolution and becomes trivalent. The solid compound resulting from the dissolution is a fluoro-antimonate: U(SbF{sub 6}){sub 3}. (author) [French] On a etudie les melanges liquides anhydres: peroxyde d'azote-acide fluorhydrique et pentafluorure d'antimoine-acide fluorhydrique comme solvants d'elements lourds interessant l'energie nucleaire: uranium, thorium, zirconium et de quelques uns de leurs composes. Pour les melanges N{sub 2}O{sub 4}-HF on a egalement effectue des mesures de conductivite electrique, ainsi que des spectres d'absorption infrarouge en phase liquide. Le tetrafluorure d'uranium et le tetrafluorure de zirconium sont beaucoup plus solubles dans les melanges N{sub 2}O{sub 4}-HF que dans l'acide fluorhydrique. L'uranium dissous dans ces melanges est a l'etat pentavalent. Dans les melanges SbF{sub 5}-HF l'uranium se dissout avec degagement d'hydrogene et passe a l'etat trivalent. Le compose solide resultant de la dissolution est un fluoantimoniate: U(SbF{sub 6}){sub 3}. (auteur)

  19. Behaviour of trivalent actinides and lanthanide elements in chloride solution; Comportement des lanthanides et transuraniens trivalents en milieu chlorhydrique

    Energy Technology Data Exchange (ETDEWEB)

    Marin, B [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    The aim of this work is to compare the complexation in chloride solutions of trivalent lanthanides and actinides. We have first studied the solvatation of these cations without complexation. We found a difference between Am, Cm and Rare Earths (we can separate lanthanides into Light and Heavy Rare Earths). For studying the complexation we choose the technic of electrophoresis on paper after establishing a simple theory of mobilities in complex solutions. The hydrolysis of these cations was studied and compared in chloride solutions. We have then studied the complexation with the Cl{sup -} ligand in some solutions: HCl, NH{sub 4}Cl, CaCl{sub 2}, CeCl{sub 3}, LiCl. We have established that the complexation is the same in dilute HCl solutions but in concentrated solutions the trivalent actinides are more complexed. This difference is sharper in LiCl solutions. We also proposed the different models of complex in these solutions. (author) [French] Le but de ce travail est de comparer les transuraniens et lanthanides trivalents au point de vue de leur complexation en solution chlorhydrique. Nous avons ete amenes tout d'abord a etudier la solvatation de ces cations non complexes. C'est ainsi que nous pouvons constater une difference entre Am, Cm et les lanthanides. Ces derniers pouvant se separer en lanthanides legers et lanthanides lourds. Pour etudier la complexation nous avons utilise l'electrophorese sur papier apres avoir donne une theorie simple des mobilites en milieu complexant. Apres avoir etudie et compare l'hydrolyse de ces divers cations en solution chlorhydrique, nous avons etudie leur complexation avec l'ion Cl{sup -} dans dans divers milieux: HCl, NH{sub 4}Cl, CaCl{sub 2}, CeCl{sub 3}, LiCl. ous avons note qu'en solution HCl les deux series se comportent de la meme facon pour des concentrations faibles en Cl{sup -} mais que les transuraniens se complexent plus fortement dans les solutions concentrees. Cette difference s'accroit encore dans les milieux

  20. Effects of combustion emissions from the Eurasian continent in winter on seasonal δ 13C of elemental carbon in aerosols in Japan

    Science.gov (United States)

    Kawashima, Hiroto; Haneishi, Yuya

    2012-01-01

    We investigated suspended particulate matter (SPM, particles with a 100% cut-off aerodynamic diameter of 10 μm) and PM2.5 (particles with a 50% cut-off aerodynamic diameter of 2.5 μm) concentrations in aerosols sampled in Akita Prefecture, Japan, from April 2008 to January 2010, and the carbon isotope ratios (δ 13C) of elemental carbon (EC) in both SPM and PM2.5 and in samples from possible sources. We also determined the ion contents of SPM and estimated the back trajectories of air masses arriving at Akita Prefecture during the study period. The SPM concentration was very low (annual average, 15.2 μg m -3), and it tended to be higher in spring and lower in winter. We attributed the higher SPM in spring to dust storms brought from the Asian continent. The average annual PM2.5 concentration was 8.6 μg m -3. δ 13C of source samples (gasoline and diesel vehicle exhaust, fireplace soot, open biomass burning emissions, street dust, soil, charcoal, and coal) ranged from -34.7‰ to -1.8‰. δ 13C values of soot from gasoline light-duty (-24.4 ± 0.7‰) and passenger vehicles (-24.1 ± 0.6‰) were very similar to that of soot from all diesel vehicles (-24.3 ± 0.3‰). δ 13C was enriched in SPM in winter compared with summer values, moreover, only a slight seasonal trend was detected in δ 13C in PM2.5. From these data and the source results, we hypothesized that the enrichment of δ 13C of SPM and PM2.5 in winter was a long-range effect of overseas combustion processes such as coal combustion. In addition, δ 13C of SPM was correlated with Cl - and Mg 2+ contents in SPM, suggesting the influence of sea salt. We verified this hypothesis by back trajectory analyses. The results indicated a continental influence effects on EC of SPM and PM2.5 in winter.

  1. Extraction apparatus used in the treatment of irradiated fuels; Les appareils d'extraction utilises dans le traitement des combustibles irradies

    Energy Technology Data Exchange (ETDEWEB)

    Faugeras, P; Talmont, X [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The two qualities necessary in an extractor in the case of solvent extraction of radioactive materials are that they should occupy little space and require little maintenance. In this paper various types of apparatus designed to this effect are examined: firstly mixer-decanter types with mechanical shaking and with shaking and decantation ultrasonically accelerated; then pulsed columns; finally hydro-cyclones. The chemical engineering studies peculiar to the running, supply and control of each of these extractors are described in detail. In certain cases some results obtained on radioactive solutions on a pilot scale are given. (author) [French] Faible encombrement, peu d'entretien, telles sont les deux qualites qu'un extracteur doit posseder dans le cas d'extraction par solvant de matieres radioactives. Dans ce texte seront examines differents types d'appareils concus dans cet esprit: d'abord les appareils typez melangeurs-decanteurs a agitation mecanique, a agitation et decantation accelerees aux ultra-sons; puis les colonnes pulsees; enfin les hydrocyclones. Pour chacun de ces extracteurs seront detaillees les etudes de genie chimique propres a son fonctionnement, a son alimentation, a son controle. Pour certains seront notes quelques resultats obtenus sur des solutions radioactives a l'echelle pilote. (auteur)

  2. Chronic exposure of ecosystems and public to elements in trace contributions; L'exposition chronique des ecosystemes et du public aux elements en traces contributions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The needs in radiation protection come towards the question of chronic contaminations by trace elements or radioactive compounds. The chronicity induces to take into account a whole of redistribution mechanisms more important than the only ways of the most direct transfer. In the case of environment, that is going to become one of the way of public contamination is a target to protect, the important work is to link the contamination situation to eventual consequences on the ecosystems situation. (N.C.)0.

  3. Thermo-mechanical behaviour modelling of particle fuels using a multi-scale approach; Modelisation du comportement thermomecanique des combustibles a particules par une approche multi-echelle

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, V.

    2009-12-15

    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

  4. Presentation of the health impact evaluation study of atmospheric emissions of a major coal combustion installation; Mise a jour de l'etude d'evaluation de l'impact sur la sante des rejets atmospheriques des tranches charbon d'une grande installation de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Bonnard, R

    2004-12-15

    In the framework of a working group on the major installations, a study has been realized on a today coal combustion installation. The direct risk by inhalation and the risks bond to indirect exposure of atmospheric releases were analyzed. The calculation method is explained and the uncertainties are discussed to present the results. (A.L.B.)

  5. Improvement of shacking helical elevators used in spent fuel reprocessing. Perfectionnement aux elevateurs helicoidaux a secousses, utilises dans le traitement des combustibles irradies

    Energy Technology Data Exchange (ETDEWEB)

    Tucoulat, D.; Kerlau, D.; Cagin, R.; Pellier, R.; Tarnero, M.; Saudray, D.

    1991-01-25

    For reprocessing cut spent fuel elements are introduced in a tank and raised gradually with an helical ramp by a back and forth motion around a vertical axis. Spent fuel is dissolved and hulls are recovered at the top of the ramp.

  6. Analytic studies on pollutant deposition through domestic coal combustion - influence of the current structural change on pollution in an urban region. Final report; Analytische Untersuchungen zum Schadstoffeintrag durch den Hausbrand - Auswirkungen des gegenwaertigen Strukturwandels auf die urbane Belastungssituation. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Engewald, W.; Knobloch, T.; Asperger, A.

    1996-12-31

    In the present paper the author reports on the continuation of an OEKOR part project in which he had undertaken a chemical characterisation of emissions from domestic brown coal combustion. On the basis of a partitioning by land use of the Greater Leipzig region he initiated long-term observations of local pollution levels for the various structural types of land. The aim of the work was to facilitate a comprehensive analysis of local air quality in terms of VOC levels. The current concern about VOCs results from the toxicological risk they have been proven to pose to the human organism and from their relevance to the chemistry of the atmosphere (e.g., as precursors of ground-level ozone and other oxidising agents). The task to be accomplished was broken down into the following main steps: Development and trial of a sampling and analysis method for determining an as wide a spectrum of environmental VOCs as possible; elaboration of a measuring strategy for obtaining results of high representativeness and power; installation and operation of pollution monitoring sites in selected structural types of area characteristic of Leipzig; execution of measuring campaigns of several weeks each at selected sites during both winter and summer periods. (orig./MSK) [Deutsch] In Fortsetzung eines vom Berichterstatter bearbeiteten OeKOR-Teilprojekts zur chemischen Charakterisierung von Emissionen aus dem Hausbrand von Braunkohle galt es, auf der Basis einer an der Flaechennutzung ausgerichteten Untergliederung der Stadtregion Leipzig in unterschiedliche Strukturtypen langfristige Immissionsbeobachtungen zu beginnen mit dem Ziel, eine Zustandsanalyse des Umweltmediums Luft bezueglich des Gehalts an fluechtigen organischen Verbindungen (VOC) in ihrer gesamten Breite zu ermoeglichen. Das verstaerkte Interesse an diesen Verbindungen resultiert aus dem fuer eine Reihe von VOC belegten toxikologischen Gefahrenpotential fuer den menschlichen Organismus sowie ihrer atmosphaerenchemischen

  7. Oxidation and Reduction of Iron-Titanium Oxides in Chemical Looping Combustion: A Phase-Chemical Description Oxydation et réduction des minerais de fer-titane dans la combustion en boucle chimique

    Directory of Open Access Journals (Sweden)

    den Hoed P.

    2011-05-01

    Full Text Available Ilmenite (FeTiO3 is being explored as an oxygen carrier in chemical looping processes. Its reduction and oxidation are described by the system Fe-Fe2O3-TiO2-Ti2O3. The phase diagram at 1 000°C, presented here, offers a useful tool for predicting reactions and their products. We see that Fe2TiO5 (pseudobrookite and TiO2 (rutile form a stable phase assemblage following the oxidation of FeTiO3 (ilmenite in air. The subsequent reduction of Fe2TiO5 at oxygen partial pressures of 10-15.5atm stabilizes Fe1.02Ti0.98O3, a solid solution of ilmenite. Further reduction will produce metallic iron, which compromises the integrity of the oxygen carrier for chemical looping processes. We speculate that the reduction of Fe-Ti oxides in several practical instances does not reach completion (and equilibrium under the imposed atmospheres operating in fuel reactors. L’ilménite (FeTiO3 est considéré comme un transporteur d’oxygène potentiel pour les procédés en boucle chimique. Ses mécanismes de réduction et d’oxydation sont décrits à travers le système Fe-Fe2O3-TiO2-TiO3. Le diagramme de phase à 1 000°C, présenté ici, est un outil utile pour prédire les réactions et les produits. Nous constatons que Fe2TiO5 (pseudobrookite et TiO2 (rutile forment un assemblage de phase stable après oxydation de l’ilménite (FeTiO3 dans l’air. La réduction subséquente de Fe2TiO5 à la pression partielle de 10−15,5atm stabilise vers Fe1.02Ti0.98O3, une solution solide d’ilménite. Une réduction plus poussée va produire du fer métallique et compromettre l’intégrité du transporteur d’oxygène dans la boucle chimique. Il est probable que la réduction des oxydes Fe-Ti ne soit pas, en pratique, complète et n’atteigne pas l’équilibre dans les conditions rencontrées en opération dans les réacteurs de réduction.

  8. Design of the fuel element 'snow-flake' in uranium oxide, canned with aluminium, for the experimental reactor EL 3 (1960); Etude d'un element combustible en oxyde d'uranium gaine d'aluminium, type ''cristal de neige'' pour la pile EL 3 (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Gauthron, M; Guibert, B [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    This report sums up the main studies have been carried out on the fuel element 'Snowflake' (uranium oxide, canned with aluminium), designed to replace the present element of the experimental reactor EL3 in order to increase the reactivity without modifying the neutron flux/thermal power ratio. (author) [French] Ce rapport resume les principales etudes qui ont ete faites sur l'element combustible 'Cristal de Neige' (a oxyde d'uranium, gaine d'aluminium) destine a remnlacer l'element actuel du reacteur experimental EL3, afin d'en augmenter la reactivite sans modifier le rapport flux neutronique-puissance thermique. (auteur)

  9. Safe management of actinides in the nuclear fuel cycle: Role of mineralogy; La gestion des actinides dans le cycle du combustible nucleaire: le role de la mineralogie

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, R.C. [Department of Nuclear Engineering and Radiological Sciences, Department of Geological Sciences, Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-1005 (United States)

    2011-02-15

    During the past 60 years, more than 1800 metric tonnes of Pu, and substantial quantities of the 'minor' actinides, such as Np, Am and Cm, have been generated in nuclear reactors. Some of these transuranium elements can be a source of energy in fission reactions (e.g., {sup 239}Pu), a source of fissile material for nuclear weapons (e.g., {sup 239}Pu and {sup 237}Np), and of environmental concern because of their long-half lives and radiotoxicity (e.g., {sup 239}Pu and {sup 237}Np). There are two basic strategies for the disposition of these heavy elements: (1) to 'burn' or transmute the actinides using nuclear reactors or accelerators; (2) to 'sequester' the actinides in chemically durable, radiation-resistant materials that are suitable for geologic disposal. There has been substantial interest in the use of actinide-bearing minerals, especially isometric pyrochlore, A{sub 2}B{sub 2}O{sub 7} (A rare earths; B = Ti, Zr, Sn, Hf), for the immobilization of actinides, particularly plutonium, both as inert matrix fuels and nuclear waste forms. Systematic studies of rare-earth pyrochlores have led to the discovery that certain compositions (B = Zr, Hf) are stable to very high doses of alpha-decay event damage. Recent developments in our understanding of the properties of heavy element solids have opened up new possibilities for the design of advanced nuclear fuels and waste forms. (author)

  10. The Role of Attrition and Solids Recovery in a Chemical Looping Combustion Process Effet de l’attrition et de la récupération des particules dans le procédé de combustion en boucle chimique

    Directory of Open Access Journals (Sweden)

    Kramp M.

    2011-05-01

    Full Text Available In the present work, the steady-state behavior of a Chemical Looping Combustion process of interconnected fluidized bed reactors is simulated. The simulations have been carried out in two different scales, 50 kWth and 100 MWth. Attrition model derived from small scale laboratory experiments has been employed for the prediction of the process behavior in terms of attrition and Oxygen Carrier loss. Information on Oxygen Carrier characteristics and reaction kinetics were taken from literature. Realistic circulation mass flows of Oxygen Carrier particles are obtained and Oxygen Carrier losses are quantified. The large scale process looses significantly more Oxygen Carrier than the small scale process based on the same amount of thermal energy produced. Incomplete conversion in the air reactor could be identified as a critical point. Another issue is the fuel gas bypassing the Oxygen Carrier particles through bubbles in the large scale process which leads to lowered fuel conversions. The simulations indicate that a similar performance of a pilot scale and a large scale process is not guaranteed due to the scale-up effect on fluid dynamics. Furthermore, the simulations allow an assessment of the influence of the quality of the solids recovery system on the Oxygen Carrier loss. The distribution of the losses between possible origins is investigated and different changes in the solids recovery system are discussed regarding their potential to decrease the Oxygen Carrier loss. For example, the addition of a second-stage cyclone after the air reactor of the large scale process reduces the Oxygen Carrier loss significantly. Le présent travail propose un modèle de simulation en continu du procédé de combustion en boucle chimique constitué de deux lits fluidisés interconnectés. Les simulations ont été conduites à deux échelles 50 kWth correspondant à une installation pilote et 100 MWth correspondant à une installation industrielle. Un modèle d

  11. Combustion engineering

    CERN Document Server

    Ragland, Kenneth W

    2011-01-01

    Introduction to Combustion Engineering The Nature of Combustion Combustion Emissions Global Climate Change Sustainability World Energy Production Structure of the Book   Section I: Basic Concepts Fuels Gaseous Fuels Liquid Fuels Solid Fuels Problems Thermodynamics of Combustion Review of First Law Concepts Properties of Mixtures Combustion StoichiometryChemical EnergyChemical EquilibriumAdiabatic Flame TemperatureChemical Kinetics of CombustionElementary ReactionsChain ReactionsGlobal ReactionsNitric Oxide KineticsReactions at a Solid SurfaceProblemsReferences  Section II: Combustion of Gaseous and Vaporized FuelsFlamesLaminar Premixed FlamesLaminar Flame TheoryTurbulent Premixed FlamesExplosion LimitsDiffusion FlamesGas-Fired Furnaces and BoilersEnergy Balance and EfficiencyFuel SubstitutionResidential Gas BurnersIndustrial Gas BurnersUtility Gas BurnersLow Swirl Gas BurnersPremixed-Charge Engine CombustionIntroduction to the Spark Ignition EngineEngine EfficiencyOne-Zone Model of Combustion in a Piston-...

  12. Report by the AERES on the unit: Fuel Study Department (DEC) under the supervision of the establishments and bodies: Atomic Energy and Alternative Energies Commission (CEA); Rapport de l'AERES sur l'unite: Departement d'Etudes des Combustibles (DEC) sous tutelle des etablissements et organismes: Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-03-15

    This report is a kind of audit report on a research laboratory, the DEC (Departement d'Etudes des Combustibles, Fuel Study Department) which comprises four departments: a department of analysis and characterization of fuel behaviour (SA3C) which comprises four laboratories, a Plutonium, Uranium and Minor Actinides department (SPUA) which comprises four laboratories, a department for the investigation and simulation of fuel behaviour (four laboratories) and the Leca-Star department (3 laboratories and a project group). The authors discuss an assessment of the whole unit activities in terms of strengths and opportunities, aspects to be improved, risks and recommendations, productions and publications on different themes (fundamental research on fuels, fuel design, fabrications, characterizations and property measurements, experimental irradiations, characterization of irradiated fuels and chemical and radio-chemical analysis, modelling and simulation). A more detailed assessment is presented for each theme in terms of scientific quality, influence and attractiveness (awards, recruitment capacity, capacity to obtain financing and to tender, participation to international programs), strategy and governance, and project

  13. Study of deuterons induced nuclear reactions on light elements (N, Al and Si): Application to containment materials of radioactive wastes; Etude des reactions nucleaires induites par des deuterons sur des elements legers (N, Al, Si): application aux materiaux de confinement des dechets radioactifs

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrino, St

    2004-03-01

    Nuclear reaction analysis is well adapted to the quantification of light element. Profiles of concentration in order to follow elements migration into materials can be undertaken. This technique is used to study the behavior of the future matrices for nuclear waste containment. This technique is isotopic, characterized by a good signal-to-background ratio and a very low detection limit. The probability of a nuclear reaction is linked to a parameter called 'cross section' we have to know in order to carry out quantitative analysis. We have determined excitation curves for nitrogen, aluminium and silicon. These experiments were done with deuterons from 0.5 to 2 MeV. Two methods for the cross section characterization are presented and are in agreement with each other. The second one reduces uncertainty. Data are incorporated in the simulation software SIMNRA. We have compared the results obtained on different samples when we use data in literature or data of the study. We have noticed a great fit improvement with the data of this study. The new cross sections of this work will be integrated in the general data base SIGMABASE. Applications on materials such as Si{sub 3}N{sub 4}, nano-metric powders, WCN and nuclear glass YLaMgSiAlON studied for radioactive waste containment are also presented. (author)

  14. Micromechanical simulation of Uranium dioxide polycrystalline aggregate behaviour under irradiation; Modele numerique micro-mecanique d'agregat polycristallin pour le comportement des combustibles oxydes

    Energy Technology Data Exchange (ETDEWEB)

    Pacull, J.

    2011-02-15

    In pressurized water nuclear power reactor (PWR), the fuel rod is made of dioxide of uranium (UO{sub 2}) pellet stacked in a metallic cladding. A multi scale and multi-physic approaches are needed for the simulation of fuel behavior under irradiation. The main phenomena to take into account are thermomechanical behavior of the fuel rod and chemical-physic behavior of the fission products. These last years one of the scientific issue to improve the simulation is to take into account the multi-physic coupling problem at the microscopic scale. The objective of this ph-D study is to contribute to this multi-scale approach. The present work concerns the micro-mechanical behavior of a polycrystalline aggregate of UO{sub 2}. Mean field and full field approaches are considered. For the former and the later a self consistent homogenization technique and a periodic Finite Element model base on the 3D Voronoi pattern are respectively used. Fuel visco-plasticity is introduced in the model at the scale of a single grain by taking into account specific dislocation slip systems of UO{sub 2}. A cohesive zone model has also been developed and implemented to simulate grain boundary sliding and intergranular crack opening. The effective homogenous behaviour of a Representative Volume Element (RVE) is fitted with experimental data coming from mechanical tests on a single pellet. Local behavior is also analyzed in order to evaluate the model capacity to assess micro-mechanical state. In particular, intra and inter granular stress gradient are discussed. A first validation of the local behavior assessment is proposed through the simulation of intergranular crack opening measured in a compressive creep test of a single fuel pellet. Concerning the impact of the microstructure on the fuel behavior under irradiation, a RVE simulation with a representative transient loading of a fuel rod during a power ramp test is achieved. The impact of local stress and strain heterogeneities on the multi

  15. Thermal Shock Tests on UO{sub 2} Small Spheres; Essais de choc thermique sur des elements spheriques de UO{sub 2}; Ispytaniya nebol'shikh sharikov iz UO{sub 2} teplovykh udarom; Ensayo de pequenas esferas de UO{sub 2} por choque.termico

    Energy Technology Data Exchange (ETDEWEB)

    Perona, G.; Brutto, E.; Galbusera, U.; Palladino, G.; Sesini, R. [Centro Informazioni Studi Esperienze, Milan (Italy)

    1963-11-15

    If UO{sub 2} small spheres are used as fuel in a reactor in contact with the cooler, it is necessary to know the maximum value of the thermal stress, due to the work conditions in the reactor, which the small spheres are able to withstand without breaking. These conditions can be calculated if the physical properties of the material are known. Owing to the considerable number of properties involved, and in consideration of the uncertainty which always exists in each of them, it is preferable to test directly the spheres, submitting them to the same kind of stresses that they undergo in thereactor. In this work a thermal shock method for the small spheres has been studied, while conditions are indicated in which this method can reproduce stress conditions directly comparable with those existing in the reactor. As for small spheres, the difficulty consists in producing coolings with very high values of the coefficient of surface heat transfer. The experimental methods are described and the results obtained are indicated. The application of this method seems to be very interesting particularly in the field of the technological research for improving the characteristics of the UO{sub 2} small spheres by means of additives. In fact it allows the control of the total interesting effect with a single measurement. (author) [French] Si l'on veut utiliser comme combustible dans un reacteur des elements spheriques de UO{sub 2} en contact avec le refroidisseur, il faut au prealable determiner la valeur maximum de la contrainte thermique - due aux conditions regnant dans le reacteura laquelle les elements sont capables de resister sans se fissurer. Il est possible de calculer ces conditions si l'on connait les proprietes physiques du materiau utilise. En raison du nombre important des proprietes a prendre en consideration, et compte tenu de l'incertitude qui existe toujours pour chacune d'elles, il est preferable de faire des essais thermiques en soumettant directement les

  16. Standard elements; Elements standards

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Following his own experience the author recalls the various advantages, especially in the laboratory, of having pre-fabricated vacuum-line components at his disposal. (author) [French] A la suite de sa propre experience, l'auteur veut rappeler les divers avantages que presente, tout particulierement en laboratoire, le fait d'avoir a sa disposition des elements pre-fabriques de canalisations a vide. (auteur)

  17. Long term developments in irradiated natural uranium processing costs. Optimal size and siting of plants; Perspectives a long terme des couts de traitement de l'uranium naturel irradie. Tailles et localisations optimales des usines

    Energy Technology Data Exchange (ETDEWEB)

    Thiriet, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Oger, C; Vaumas, P de [Saint-Gobain Nucleaire, 92 - Courbevoie (France)

    1964-07-01

    processing plants are shown, different from those in part two. The indirect effect of these reprocessing programmes on the availability of plutonium, and therefore on the possibility.of undertaking plutonium burning reactor programmes, must be taken into account. (authors) [French] L'objet de cette communication est d'apporter une contribution a la solution du probleme du choix des tailles et des localisations optimales des usines de traitement des combustibles nucleaires irradies, associees a des programmes de puissance electrique installee. Dans une premiere partie, on etudie la structure des couts d'investissements et d'exploitation des usines de traitement de l'uranium naturel irradie, l'influence de la taille des usines sur ces couts et ces structures de couts. Au cout de traitement de l'uranium naturel irradie s'ajoute d'autre part le cout du transport des combustibles irradies des lieux de production aux sites des usines de traitement. La recherche du cout minimum pour la production d'un pays ou d'un ensemble de pays fait donc intervenir a la fois la taille et la localisation des usines. On indique les couts de transport previsibles pour l'uranium naturel irradie et la structure de ces couts (transport, assurance, couts et amortissement des containers). Dans une deuxieme partie, et pour differents echeanciers de combustibles irradies a traiter chaque annee, on determine les tailles et les localisations optimales des usines de traitement et la sensibilite de ces resultats, aux hypotheses de base concernant le cout du traitement, le cout du transport, l'annee de demarrage du programme d'usines, l'horizon choisi. - le probleme de nature combinatoire, assez complexe, est resolu par l'application des methodes de la programmation dynamique. - on montre que les methodes sont egalement applicables au probleme du choix des tailles et des localisations optimales des usines de traitement des elements du type MTR, associees aux programmes de reacteurs de recherche ainsi qu

  18. Behavior of silicon in nitric media. Application to uranium silicides fuels reprocessing; Comportement du silicium en milieu nitrique. Application au retraitement des combustibles siliciures d'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Cheroux, L

    2001-07-01

    Uranium silicides are used in some research reactors. Reprocessing them is a solution for their cycle end. A list of reprocessing scenarios has been set the most realistic being a nitric dissolution close to the classic spent fuel reprocessing. This uranium silicide fuel contains a lot of silicon and few things are known about polymerization of silicic acid in concentrated nitric acid. The study of this polymerization allows to point out the main parameters: acidity, temperature, silicon concentration. The presence of aluminum seems to speed up heavily the polymerization. It has been impossible to find an analytical technique smart and fast enough to characterize the first steps of silicic acid polymerization. However the action of silicic species on emulsions stabilization formed by mixing them with an organic phase containing TBP has been studied, Silicon slows down the phase separation by means of oligomeric species forming complex with TBP. The existence of these intermediate species is short and heating can avoid any stabilization. When non irradiated uranium silicide fuel is attacked by a nitric solution, aluminum and uranium are quickly dissolved whereas silicon mainly stands in solid state. That builds a gangue of hydrated silica around the uranium silicide particulates without preventing uranium dissolution. A small part of silicon passes into the solution and polymerize towards the highly poly-condensed forms, just 2% of initial silicon is still in molecular form at the end of the dissolution. A thermal treatment of the fuel element, by forming inter-metallic phases U-Al-Si, allows the whole silicon to pass into the solution and next to precipitate. The behavior of silicon in spent fuels should be between these two situations. (author)

  19. Modelling porous active layer electrodes of proton exchange membrane fuel cells; Modelisation des couches actives d'electrodes volumiques de piles a combustible a membrane echangeuse de protons

    Energy Technology Data Exchange (ETDEWEB)

    Bultel, Yann

    1997-07-01

    This work focusses on the modeling of mass, charge and heat transfer in the active layers of the volume electrodes of proton exchange membrane fuel cells (PEMFC). A first part describes the structure of fuel cells and the physico-chemical processes taking place at the electrodes. An analysis of the classical models encountered in the literature shows that they all assume that the electro-catalysts is uniformly distributed in a plane or in volume. In a second part, the modeling of mass and charge transport phenomena has been carried out with a numerical calculation software which uses the finite-elements method and which allows to take into consideration the discrete distribution of the catalyst in nano-particulates. The simulations show the limitations of the catalyst use because of the diffusion and ionic ohmic drop both at the electrolyte and particulates scale. In order to improve the modeling of PEMFC fuel cells, the classical models have been modified to consider these local contributions. They require only simple numerical methods, like the finite-differences one. When applied to the oxygen reduction at the cathode or to the hydrogen oxidation at the anode, these models allow to determine the kinetics parameters (exchange current densities and slopes of the Tafel lines) after correction of the active layer diffusion. A modeling of the heat transfers at the active layers scale is proposed. The model takes into account the convective heat transfers between the solid phases and the gas, the electro-osmosis water transfer, and the generation of heat by joule effect and by the electrochemical reactions. Finally, the last chapter presents a study of the reaction mechanisms in the case of porous electrodes using the impedances method. Numerical and analytical models have been developed to calculate the electrode impedances and are applied to the study of oxygen reduction and hydrogen oxidation. (J.S.)

  20. Sorption Regularities in Behaviour of Fission-Product Elements during Filtration of their Solutions through Ground; Lois de l'Absorption des Elements Radioactifs Lors du Filtrage des Solutions a Travers les Terrains; 0417 0410 041a 041e 041d 0414 ; Leyes de la Absorcion de los Elementos Radiactivos Cuando se Filtran Soluciones a Traves de las Formaciones Geologicas

    Energy Technology Data Exchange (ETDEWEB)

    Spitsyn, V. I.; Balukova, V. D.; Gromov, V. V.; Zakharov, S. I.; Zhagin, B. P.; Spiridonov, F. M.

    1960-07-01

    Research on the sorption of radioisotopes under natural conditions employing the controlled filtration process was performed. Radioisotopes were introduced into the solution as soon as filtration had become steady and the process continued for four months. Soil samples were then taken by drilling at different depths and analysed to determine their radioisotope content. Diffusion of radioisotopes was observed at depths of up to 10 m; two distinct boundaries of soil-activity decrease were ascertained: at the surface of the site and at the depth of the solution filtration front. In addition, the radiostrontium absorption by natural sorbents, principally pure minerals widely distributed in soils and subsoils, was investigated separately. The presence of calcium ions, even in small quantities, sharply reduces the degree of radiostrontium sorption. However, other conditions being equal, strontium may be absorbed to a greater extent than calcium, according to the composition of the sorbent. The field investigations of radiostrontium sorption and migration showed that when filtering radioactive solutions two possible variants have to be taken into account. In the first case the solutions are discharged into soil unaffected by any flow of ground water. In this situation the radiostrontium is retained by the soil. In the second case, the radioisotopes proceed directly into the water-bearing horizon. The radiostrontium will then migrate with the ground water flow and through the soil and this migration will be further affected by the sorption and desorption processes occurring. The experiments performed demonstrate the ease with which long-lived radioisotopes migrate under natural conditions and call attention to the need for thorough study of ground water problems in connexion with various methods of disposing of radioactive waste into ground. (author) [French] En declenchant un processus de filtration, il a ete possible d'etudier l'absorption des elements radioactifs dans

  1. Metallurgical and mechanical behaviours of PWR fuel cladding tube oxidised at high temperature; Comportements metallurqigue et mecanique des materiaux de gainage du combustible REP oxydes a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Stern, A

    2007-12-15

    were mechanically tested at various temperatures and for various mean oxygen contents. This allowed us, first, to establish ductile to brittle transition temperatures (for a given oxygen content), and second, to establish behaviour laws for those materials (function of oxygen content and temperature). It was thus possible to start some preliminary finite element calculations to describe the cladding behaviour under the standard technological ring compression test. (author)

  2. Measurement of the in-pile core temperature of an EL-4 pencil element, first charge (can of type-347 stainless steel, 0.4 mm thick, UO{sub 2} fuel, 11 mm diameter). Determination of the apparent thermal conductivity integral of in-pile UO{sub 2}; Mesure de la temperature a coeur en pile d'un crayon EL-4 1er jeu (gaine acier inoxydable, nuance 347 - epaisseur 0,4 mm - combustible UO{sub 2} - diametre 11 mm). Determination de l'integrale de conductibilite thermique apparente de l'UO{sub 2} en pile

    Energy Technology Data Exchange (ETDEWEB)

    Lavaud, B; Ringot, C; Vignesoult, N [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1966-11-01

    'un element combustible EL-4, type premier jeu, a gaine en acier inoxydable. On mesure cette temperature au coeur du crayon en pile a l'aide d'un thermocouple pour haute temperature: tungstene-rhenium a gaine tantale. Le crayon est place dans des conditions de fonctionnement analogues a celles de EL-4, tant en ce qui concerne la puissance specifique et la temperature sur gaine que la pression externe sur la gaine. La puissance specifique est obtenue dans le reacteur EL-3 avec un enrichissement de l'UO{sub 2} legerement superieur a celui normalement prevu pour EL-4. La temperature de gaine et la pression visees sont realisees a l'aide d'un conteneur d'irradiation en zircaloy-2 et a remplissage NaK, adapte, aux conditions du reacteur EL-3. - Les temperatures de l'UO{sub 2} a coeur, et de la surface de la gaine etant mesurees; - La puissance etant calculee a partir des echanges thermiques dans le conteneur etalonne en laboratoire; - La chute de temperature au contact UO{sub 2}-gaine etant deduite de mesures faites en laboratoire dans des conditions de flux calorifique comparables et sous une atmosphere de gaz correspondant au debut de la vie de l'element combustible; on peut tracer la courbe integrale de conductibilite. Les examens micro-graphiques de la structure de l'oxyde permettent de verifier la repartition des temperatures dans l'oxyde, deduite de l'integrale de conductibilite thermique. (auteurs)

  3. Propagation of thermal neutrons in mock-up screw-shaped steel elements with water protection; Propagation des neutrons thermiques dans des fausses cartouches d'acier en helice dans une protection d'eau. Programme tournesol 3

    Energy Technology Data Exchange (ETDEWEB)

    Devillers, C L; Lanore, J M [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-07-01

    This report treats the streaming of thermal neutrons in a cylindrical duct in light water. The duct contains a spiral iron shield. Transmission and reflection matrices are used to describe the probabilities for the thermal neutrons to be absorbed or to be scattered on the surfaces. The neutron paths across the void are represented by geometrical matrices. The numerical resolution is performed by the Monte-Carlo method. (authors) [French] Dans ce rapport on traite un probleme de fuites de neutrons thermiques dans un canal cylindrique plonge dans l'eau et obture par un ecran helicoidal en acier. On utilise des matrices de transmission-reflexion pour decrire les probabilites d'absorption et de diffusion des neutrons sur les parois et l'helicoide et des matrices de correspondance geometrique pour representer la propagation dans le vide. La resolution numerique se fait par une methode de Monte-Carlo. (auteur)

  4. Combustion physics

    Science.gov (United States)

    Jones, A. R.

    1985-11-01

    Over 90% of our energy comes from combustion. By the year 2000 the figure will still be 80%, even allowing for nuclear and alternative energy sources. There are many familiar examples of combustion use, both domestic and industrial. These range from the Bunsen burner to large flares, from small combustion chambers, such as those in car engines, to industrial furnaces for steel manufacture or the generation of megawatts of electricity. There are also fires and explosions. The bountiful energy release from combustion, however, brings its problems, prominent among which are diminishing fuel resources and pollution. Combustion science is directed towards finding ways of improving efficiency and reducing pollution. One may ask, since combustion is a chemical reaction, why physics is involved: the answer is in three parts. First, chemicals cannot react unless they come together. In most flames the fuel and air are initially separate. The chemical reaction in the gas phase is very fast compared with the rate of mixing. Thus, once the fuel and air are mixed the reaction can be considered to occur instantaneously and fluid mechanics limits the rate of burning. Secondly, thermodynamics and heat transfer determine the thermal properties of the combustion products. Heat transfer also plays a role by preheating the reactants and is essential to extracting useful work. Fluid mechanics is relevant if work is to be performed directly, as in a turbine. Finally, physical methods, including electric probes, acoustics, optics, spectroscopy and pyrometry, are used to examine flames. The article is concerned mainly with how physics is used to improve the efficiency of combustion.

  5. Analyse de la dynamique non-linéaire et du contrôle des instabilités de combustion fondée sur la "Flame Describing Function" (FDF)

    OpenAIRE

    Boudy , Frédéric

    2012-01-01

    This thesis is concerned with an investigation of combustion instabilities in premixed combustors. This problem has been the subject of a continuous effort in relation with the many issues encountered in practical systems like those used in propulsion and energy production. Combustion instabilities usually arise from the coupling between combustion and acoustic eigenmodes of the system. In most cases such resonances lead to vibrations, structural fatigue and intensified heat fluxes to the cha...

  6. Detection and location of can rupture in reactors cooled by a flow of water; Detection et localisation des ruptures de gaines sur les reacteurs refroidis par circulation d'eau

    Energy Technology Data Exchange (ETDEWEB)

    Le Meur, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    This report brings together the principal methods of fission-product detection used for water reactors. The position, type and method of adjustment is given for each detector. The methods for localizing the defective elements are explained, in particular those using water sampling or decreases in the flux. A few installations are briefly described. They correspond to particular types of reactors using boiling, pressurized or cold water. Amongst the many methods used, it can be noted that when the fuel is resistant, the installations are fairly compact. In nuclear super-heated reactors on the other hand, the study of fuel behaviour calls for larger installations. An identification of defective elements exists when the reactor structure allows it. If this is not possible, a localization in a group of elements is obtained by a flux depression. (author) [French] Ce rapport rassemble les principales methodes de detection de produits de fission utilisees pour des reacteurs a eau. On indique pour les detecteurs leurs emplacements, leurs types, leurs reglages. On explique quelles sont les methodes de localisation des elements defectueux, en particulier celles utilisant des prelevements d'eau ou des depressions de flux. Quelques installations sont decrites sommairement. Elles correspondent a des types particuliers de reacteurs a eau bouillante, pressurisee ou froide. Parmi les nombreuses methodes utilisees, on constate que les installations sont peu importantes, lorsque le combustible est resistant. Par contre dans les reacteurs a surchauffe nucleaire l'etude du comportement du combustible necessite des installations plus importantes. Une identification d'elements defectueux existe lorsque la structure du reacteur le permet. A defaut une localisation dans un groupe d'elements est obtenue par depression de flux. (auteur)

  7. Trace element and isotopic compositions of Vietnamese basalts: implications for mantle dynamics in the southeast Asian region; Compositions isotopiques et en elements en trace des basaltes vietnamiens: implications pour la dynamique du manteau en Asie du Sud-Est

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, H.; Fower, M. [Illinois Univ., Chicago, IL (United States); Nguyen, H. [Tokyo Univ. (Japan); Nguyen, X.B.; Nguyen, T.Y. [Institute of Nuclear Science and Technology, Hanoi (Viet Nam)

    1996-12-31

    Cenozoic basalts in Indo-China are part of a regional melting episode along the rifted Eurasian margin. Trace element and isotopic compositions of Vietnamese basalts are used to place constraints on the extent of lithospheric and asthenosphere contributions to the melts and possible mantle dynamic implications. The {sup 87}Sr/{sup 86}Sr, {sup 207}Pb/{sup 204}Pb, and {sup 208}Pb/{sup 204}Pb isotopic ratios of the basalts reflect minimal crustal wall rock reaction, and variable enrichment in EM1 and EM2 of a {sup 208}Pb-rich MORB-like source. Some, but not all, of this variation corresponds to the age of lithospheric sector penetrated. Basalts erupted through a cratonic, central sector (e.g. at Quang Ngai, Pleiku, Song Cau, Kong Plong, and Buon Ma Thuot) and off-cratonic, southwest sector (e.g. Phuoc Long) resemble those of EM2-rich basalts from southern and southeaster China and the South China Sea. Basalts from an off-cratonic, southeast sector (e.g. from Dalat, Xuan Loc, and the offshore Ile des Cendres-Phu Cuy complex) reflect mixing between a low- {sup 206}Pb/{sup 204}Pb, high-{sup 208}Pb/{sup 204}Pb, EM1-like component, and resemble basalts from northwest Taiwan, eastern and northeastern China, and parts of the Japan Sea. While EM2 tends to characterise lithospheric sectors, presence of EM1 in off-cratonic rather than cratonic basalts implies an asthenosphere rather than lithospheric source. Pervasive presence of EM1 in southeast Asian and marginal basin asthenosphere corresponds with thermally-anomalous mantle and may involve delaminated cratonic substrate entrained by mobile, extruded asthenosphere. (authors) 85 refs.

  8. Biofuels combustion.

    Science.gov (United States)

    Westbrook, Charles K

    2013-01-01

    This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly.

  9. Piles used for the nuclear control of materials; Empilements pour le controle nucleaire des materiaux

    Energy Technology Data Exchange (ETDEWEB)

    Raievski, V; Sautiez, B; Bailly du Bois, B; Tretiakoff, O; Thome, P; Vidal, R; Koppel Martelly, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    The devices which make it possible to check on the nuclear qualities of the materials used in reactor construction are described. These verifications bear on substantial masses of materials, following the last stage of their machining. The components found in all these are a graphite pile into which the material to be investigated is inserted, a source of neutrons made up of an Ra-Be system, and a proportional BF{sub 3} counter. The devices described here bear on checking graphite, beryllium oxide and uranium absorption, as well as on a verification of the {sup 235}U content of fuel elements. (author)Fren. [French] On decrit des dispositifs permettant de controler les qualites nucleaires de materiaux utilises dans la construction des piles. Ce controle s'effectue sur des masses importantes de materiaux apres la phase finale d'usinage. Ces dispositifs ont en commun un empilement de graphite recevant le materiau a etudier, une source de neutrons de Ra-Be et un compteur proportionnel a BF{sub 3}. Les dispositifs decrits concernent le controle de l'absorption du graphite, de la glucine et de l'uranium, ainsi que le controle de la teneur en {sup 235}U des elements de combustion. (auteur)

  10. Design of the fuel element 'snow-flake' in uranium oxide, canned with aluminium, for the experimental reactor EL 3 (1960); Etude d'un element combustible en oxyde d'uranium gaine d'aluminium, type ''cristal de neige'' pour la pile EL 3 (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Gauthron, M.; Guibert, B. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    This report sums up the main studies have been carried out on the fuel element 'Snowflake' (uranium oxide, canned with aluminium), designed to replace the present element of the experimental reactor EL3 in order to increase the reactivity without modifying the neutron flux/thermal power ratio. (author) [French] Ce rapport resume les principales etudes qui ont ete faites sur l'element combustible 'Cristal de Neige' (a oxyde d'uranium, gaine d'aluminium) destine a remnlacer l'element actuel du reacteur experimental EL3, afin d'en augmenter la reactivite sans modifier le rapport flux neutronique-puissance thermique. (auteur)

  11. Structures and properties of (U,Pu)O{sub 2} containing non-active fission products. A simulation of irradiated nuclear fuel; Structure et proprietes de (U, Pu)O{sub 2} contenant des produits de fission sous forme inactive. Une simulation de combustible nucleaire irradie

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, F [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    We have made oxides with the same uranium and plutonium content, the same stoichiometry and the same fission product content as an oxide fuel (U{sub 0,8}PuO{sub 2})O{sub 1,96} after 2 per cent burn up. We have calculated the stoichiometry changes due to irradiation and checked the calculation by X rays parameters measurements. We have calculated and measured the contraction of the oxide lattice due to fission products in solid solution. Microprobe analysis of precipitates have been made and have lead to the identification of non metallic barium containing compounds and have shown the particular behaviour of molybdenum. Some physical properties have been measured especially the electrical resistivity, the thermal diffusivity and the vapour pressure of zirconium in solid solution. (author) [French] Nous avons fabrique des oxydes dont la composition en uranium et plutonium, la stoechiometrie et la teneur en produit de fission, sont identiques a celles d'un oxyde (U{sub 0,8}PuO{sub 2})O{sub 1,96} ayant subi 2 pour cent de combustion. Nous avons calcule les changements de stoechiometrie entraines par l'irradiation et controle ces calculs par des mesures de parametre. Nous avons calcule et mesure la contraction du reseau due aux produits de fissions solubles dans la matrice. Des analyses a la microsonde des precipites de produits de fission insolubles ont ete faites et ont conduit a l'identification de composes non metalliques contenant du baryum et a la mise en evidence du role particulier du molybdene. Certaines proprietes physiques ont ete mesurees sur ces composes, en particulier la resistivite electrique, la diffusivite thermique et la tension de vapeur du zirconium dissout dans la matrice. (auteur)

  12. Effect of Carbonate Matrix on δ15N Analysis Tested for Simple Bulk Combustion on Coupled Elemental Analyzer-GC-IRMS

    Science.gov (United States)

    Saxena, D.; Grossman, E. L.; Maupin, C. R.; Roark, B.; O'Dea, A.

    2016-12-01

    Nitrogen isotopes (15N/14N) have been extensively used to reconstruct trophic structure, anthropogenic nutrient loading, ecosystem dynamics, and nutrient cycling in terrestrial and marine systems. Extending similar efforts to deep time is critical to investigate sources and fluxes of nutrients in past oceans, and explore causes of biotic turnover. To test the fidelity of N-isotope analyses of biogenic carbonate samples by simple bulk combustion, we performed two sets of experiments involving varying proportions of reagent CaCO3 (0, 2, 35 mg) and three organic standards (3.7-47.2 µg) viz. USGS40 (δ15NAir = -4.52‰), USGS41 (δ15NAir = +47.57‰), and in-house standard Rice (δ15NAir = +1.18‰). At high N contents (15-47.2 µg), δ15N values for CaCO3-amended samples are consistently either 0.5‰ higher (USGS40, -4.5‰), equivalent (Rice, 1.2‰), or 0.5‰ lower (USGS41, 47.6‰) relative to unamended samples. The difference thus depends on the δ15N of the standard relative to air. With decreasing N content (10-15 µg), δ15N values for CaCO3-amended samples diverge from expected values, with 35 mg CaCO3 samples diverging at the highest N content and 0 mg CaCO3 samples at the lowest (10 µg). The latter matches the lower sample-size limit for accurate measurement under the experimental conditions. At very low sample size (3.7-10 µg), all unamended standards show decreasing δ15N with decreasing N content, presumably because of non-linearity in instrument electronics and ion source behavior. The δ15N values of amended USGS41 also decrease with decreasing N content, but those of amended USGS40 and Rice samples increase, with samples containing more CaCO3 (35 versus 2 mg) showing greater deviation from expected values. Potential causes for deviation in δ15N values with CaCO3 amendments include N2 contamination from tin capsules and reagent CaCO3, and incomplete combustion due to energy consumption during CaCO3 decomposition. While tin capsules and reagent Ca

  13. Control of surplus oxygen in the combustion zone reduces fuel costs and NO{sub x} emissions; Verringerung der Brennstoffkosten und NO{sub X}-Emissionen durch Regelung des Sauerstoffueberschusses in der Brennzone

    Energy Technology Data Exchange (ETDEWEB)

    Boltz, Eric S. [Marathon Sensors Inc. (Germany); Baumann, Jens [Process Electronic GmbH (Germany)

    2009-06-15

    Real time in-situ measurement of oxygen content and temperature in the combustion zone of a heating boiler or furnace permits monitoring of combustion conditions at source. Measurements of oxygen surplus and of temperature at strategic points supply us with instantaneous information for optimum control of the combustion process. Accurate and rapid measurement of oxygen surplus is vital in view of the cost explosion in the case of fuels, and also for reduction of NO{sub x} emissions. Locally available commercial high-temperature oxygen sensors make it possible to solve problems of combustion control and burner regulation with only short amortization periods and high annual financial benefits in power generating plant, petrochemicals, refinery and glassworks applications. (orig.)

  14. Irradiation Behaviour of Uranium Carbide Fuels; Comportement des carbures d'uranium sous l’effet de l'irradiation; ПОВЕДЕНИЕ УРАНО-КАРБИДНОГО ТОПЛИВА ПРИ ОБЛУЧЕНИИ; Comportamiento de los combustibles de carburo de uranio frente a la irradiación

    Energy Technology Data Exchange (ETDEWEB)

    Sinizer, D. I.; Webb, B. A.; Berger, S. [Atomics International, Canoga Park, CA (United States)

    1963-08-15

    is a void-free, single-phase microstructure in the decarburized region of the originally hyperstoichiometric fuel. No carbon transfer is observed with hypo- stoichiometric U-C. Carbon removed from hyperstoichiometric (J-C fuel is readily transferred across the Na bond to carburize stainless-steel cladding in both in-pile and out-of-pile experiments. This transfer represents a possible limitation of choice of fuel composition for Na-bonded stainless-steel-clad elements. Nevertheless, available data lead to the present conclusions that stoichiometric or hyperstoichiometric U-C Na-bonded to stainless steel can be effectively used in Na-cooled power reactors. Fission-gas release or fuel swelling do not represent limitations under presently conceived Na-cooled reactor conditions. Alternative cladding materials such as Cb alloys or gas-bonded fuel elements may be required for ultra-high-temperature applications. (author) [French] Des combustibles UC ayant uùe composition quasi stoechiométrique, obtenus par fusion à l’arc électrique et enfermés dans des gaines en acier inoxydable avec lien de sodium ou de NaK, ont été irradiés à des températures au centre allant jusqu'à 1950°F (1065°C) [température moyenne: 1750°F (950°C)] et des taux de combustion allant jusqu'à 25 000 MWj/t d'U, Les combustibles stoechiométriques et légèrement tiyperstoechiométriques accusent une augmentation à peu près linéaire du diamètre pour des taux de combustion allam jusqu'à 25 000 MWj/t d'U. Pour une température au centre moyenne de 1500°F (815°C), l'augmentation de diamètre est inférieure à 3% au-dessus de 25 000 MWj/t d’U; elle est proportionnellement moindre losque la température du combustible s'abaisse. A la température moyenne de 1000°F (540°C), on observe une dilatation qui est à peu près égal à celle que l'on peut prévoir du fait de l'accumulation des produits de fission. La libération des gaz de fission est estimée à moins de 1% au-dessus de

  15. Tubular combustion

    CERN Document Server

    Ishizuka, Satoru

    2014-01-01

    Tubular combustors are cylindrical tubes where flame ignition and propagation occur in a spatially confined, highly controlled environment, in a nearly flat, elongated geometry. This allows for some unique advantages where extremely even heat dispersion is required over a large surface while still maintaining fuel efficiency. Tubular combustors also allow for easy flexibility in type of fuel source, allowing for quick changeover to meet various needs and changing fuel pricing. This new addition to the MP sustainable energy series will provide the most up-to-date research on tubular combustion--some of it only now coming out of private proprietary protection. Plentiful examples of current applications along with a good explanation of background theory will offer readers an invaluable guide on this promising energy technology. Highlights include: * An introduction to the theory of tubular flames * The "how to" of maintaining stability of tubular flames through continuous combustion * Examples of both small-scal...

  16. Advanced Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon R. [NETL

    2013-03-11

    The activity reported in this presentation is to provide the mechanical and physical property information needed to allow rational design, development and/or choice of alloys, manufacturing approaches, and environmental exposure and component life models to enable oxy-fuel combustion boilers to operate at Ultra-Supercritical (up to 650{degrees}C & between 22-30 MPa) and/or Advanced Ultra-Supercritical conditions (760{degrees}C & 35 MPa).

  17. Compound-specific isotope analysis of light elements using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) and its application to geochemistry

    International Nuclear Information System (INIS)

    Naraoka, Hiroshi; Yamada, Keita; Matsumoto, Kohei; Ishiwatari, Ryoshi

    1997-01-01

    Compound-specific isotope analysis has been developed recently using gas chromatography/combustion/mass spectrometry (GC/C/IRMS). This paper summarizes principles and progress of GC/C/IRMS, and reviews recent some important works using this new method. GC/C/IRMS is a novel tool for (1) biomarker analysis in sediments and living matter, (2) paleoenvironment analysis including reconstruction of ancient biogeochemical processes, (3) geochemical cycle study of organic compounds in a terrestrial-marine system, (4) evaluation of maturity and diagenesis of organic matter including petroleum formation, (5) ecological analysis, (6) evaluation of anthropologenic pollution in environment, (7) detection of extraterrestrial organic compounds and the formation mechanism study, (8) tracer studies in environment. (author)

  18. Study of the influence of climatic factors on the accumulation of radio-elements in plant tissue (1962); Etude de l'influence des facteurs climatiques sur l'accumulation des radioelements dans les tissus vegetaux (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Gagnaire, J; Gilly-Heuze, C; Nizia, J [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1962-07-01

    1. Here is proposed an appropriate treatment of soil able to promote absorption and accumulation of radioisotopes in aerial parts of young trees. 2. Thanks to such treatment, young trees belonging to several species appropriately selected can probably be used to detect possible contamination of soil by a radioisotope during a whole vegetation cycle. The concentration power of tissues of these trees is considerable: after being cultivated on contaminated soil for only 4 weeks, the concentration rate is about 85 in spruce-needles. Activity measurements of samples of plant tissues may become a routine process in control of soil contamination. (authors) [French] 1. Nous proposons un traitement special du sol pour favoriser l'absorption et l'accumulation de radioelements dans les parties aeriennes de jeunes arbres. 2. Grace a ce traitement, il semble possible d'utiliser de jeunes arbres appartenant a plusieurs especes convenablement choisies pour detecter une contamination eventuelle du sol par un radioelement pendant un cycle vegetatif complet. Le pouvoir de concentration de leurs tissus est important: apres quatre semaines seulement de culture sur sol contamine, le facteur de concentration (FC) est de l'ordre de 85 dans les aiguilles d'epiceas. Les mesures d'activite sur des echantillons de tissus vegetaux peuvent devenir une methode de routine pour un controle de contamination des sols. (auteurs)

  19. Study of a Slightly Enriched R Reactor Fuel by Means of a Pulsed Neutron Source; Etude d'un reacteur a combustible legerement enrichi (rubeole) a l'aide de sources pulsees de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Sagot, M.; Tellier, H. [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1962-04-01

    A Be O moderated reactor using slightly enriched uranium oxide as fuel was studied by the pulsed neutron source technique. The neutron lifetime was measured in two different cores without reflector, then attempts were made at the measurement of great negative reactivities introduced into the reactor under the following forms: decrease of the volume of the un reflected core, introduction of absorbing cadmium rods, removal of fuel at the periphery of the critical core while maintaining a constant height, and substitution of fuel elements by less reactive elements. In all cases, the results are compared with the data obtained by another type of experiment or by computation. (author) [French] Nous avons applique la methode des sources pulsees de neutrons a un reacteur utilisant de l'oxyde d'uranium legerement enrichi, modere a l'oxyde de beryllium et, apres avoir mesure le temps de vie des neutrons dans deux coeurs differents non reflechis, nous avons porte notre effort, sur la mesure de reactivites negatives importantes introduites dans le reacteur sous differentes formes: - diminution du volume du coeur non reflechi, - introduction de barres absorbantes en cadmium, - enlevement de combustible a la peripherie du coeur critique, tout en conservant une hauteur constante, - substitution d'elements de combustible par des elements moins reactifs. Dans tous les cas, les resultats sont compares aux valeurs obtenues par un autre type d'experience ou par le calcul. (auteur)

  20. Study of a Slightly Enriched R Reactor Fuel by Means of a Pulsed Neutron Source; Etude d'un reacteur a combustible legerement enrichi (rubeole) a l'aide de sources pulsees de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Sagot, M; Tellier, H [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1962-04-01

    A Be O moderated reactor using slightly enriched uranium oxide as fuel was studied by the pulsed neutron source technique. The neutron lifetime was measured in two different cores without reflector, then attempts were made at the measurement of great negative reactivities introduced into the reactor under the following forms: decrease of the volume of the un reflected core, introduction of absorbing cadmium rods, removal of fuel at the periphery of the critical core while maintaining a constant height, and substitution of fuel elements by less reactive elements. In all cases, the results are compared with the data obtained by another type of experiment or by computation. (author) [French] Nous avons applique la methode des sources pulsees de neutrons a un reacteur utilisant de l'oxyde d'uranium legerement enrichi, modere a l'oxyde de beryllium et, apres avoir mesure le temps de vie des neutrons dans deux coeurs differents non reflechis, nous avons porte notre effort, sur la mesure de reactivites negatives importantes introduites dans le reacteur sous differentes formes: - diminution du volume du coeur non reflechi, - introduction de barres absorbantes en cadmium, - enlevement de combustible a la peripherie du coeur critique, tout en conservant une hauteur constante, - substitution d'elements de combustible par des elements moins reactifs. Dans tous les cas, les resultats sont compares aux valeurs obtenues par un autre type d'experience ou par le calcul. (auteur)

  1. The Use of Fuel Gas as Stripping Medium in Atmospheric Distillation of Crude Oil L’utilisation de gaz combustible comme moyen d’extraction des fractions légères en distillation atmosphérique du pétrole brut

    Directory of Open Access Journals (Sweden)

    Plellis-Tsaltakis C.

    2011-09-01

    Full Text Available Stripping of petroleum fractions aims to remove the light ends that spoil some of their properties, such as the flash point. Stripping usually employs steam for that purpose. Except for steam, other substances can perform the same function, among them light hydrocarbons. In this article, we investigate the use of refinery fuel gas as stripping medium for a crude oil atmospheric distillation unit. L’extraction des fractions légères du pétrole vise à enlever les produits nuisibles à certaines propriétés comme le point d’éclair. Cette opération utilise habituellement de la vapeur d’eau. D’autres substances peuvent remplir la même fonction, comme les hydrocarbures légers. Dans cet article, on étudie l’utilisation du gaz combustible de la raffinerie comme moyen d’extraction des fractions légères dans une unité de distillation atmosphérique.

  2. New Instruments and Principles for the Dimensional Measurement and Measurement of Spacing of Reactor Components; Nouveaux Instruments et Procedes de Mesure des Dimensions et de l'Espacement des Elements d'un Reacteur; Novye pribory i printsipy izmereniya razmerov i raspolozheniya komponentov reaktora; Nuevos Instrumentos y Principios para Medir las Dimensiones y la Separacion Entre Componentes de Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, P. [Institut Dr. Foerster, Reutlingen, Federal Republic of Germany (Germany)

    1965-09-15

    continu, des dimensions de parties constitutives metalliques de reacteurs et explique diverses methodes de mesure pour les metaux terreux et non terreux (champs magnetiques des courants continus et des courants alternatifs, courants de Foucault). Il decrit des instruments et donne des exemples de mesure telecommandee du diametre, de l'ovalisation, de la distorsion, etc., de diverses pieces; il expose des methodes de mesure de l'espacement des elements de la zone active du reacteur. Le memoire decrit un instrument permettant d'enregistrer le profil de surface et de faire la lecture directe des valeurs de la rugosite (profondeur de rugosite, degre de polissage, direction des irregularites et valeur quadratique moyenne). Il donne des exemples typiques d'emploi de cet instrument pour les pieces d'un reacteur. L'auteur traite en particulier de la possibilite d'utiliser un petit lecteur polyvalent, a l'aide de manipulateurs, dans les zones actives et pour les matieres 'chaudes'. Il discute l'augmentation de la rugosite de surface en fonction de l'accroissement de l'irradiation. (author) [Spanish] Full text: El autor presenta los problemas de medicion del espesor de hojas y de paredes de tubos y recipientes de material austenftico y no ferroso. Se exponen dos metodos para medir el espesor de paredes sin usar elementos en contacto con las mismas: el metodo de las corrientes de Foucault para medir el espesor de hojas y recipientes de material no ferroso y austenftico, empleando bobinas de transicion, y el empleo de corrientes de Foucault para medir espesores de pared en tubos mediante bobinas anulares extensivas. Se describen los instrumentos adecuados y sus aplicaciones. El autor discute ademas la medicion de espesores de pared en componentes no ferrosos para reactores mediante el 'metodo de la esfera magnetica' y explica el principio de este nuevo procedimiento de medicion, se analiza su alcance, sobre todo para mediciones localizadas, y se describe un instrumento utilizado en

  3. 40 CFR 74.16 - Application requirements for combustion sources.

    Science.gov (United States)

    2010-07-01

    ... combustion sources. 74.16 Section 74.16 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... for combustion sources. (a) Opt-in permit application. Each complete opt-in permit application for a combustion source shall contain the following elements in a format prescribed by the Administrator: (1...

  4. Welding procedures used in the fabrication of fuel elements for the DON Reactor exponential experiment; La soldadura en la fabricacion de elementos combustibles destinados a una experiencia exponencial

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Beltran, A; Jaraiz Franco, E; Rivas Diaz, M. de las

    1965-07-01

    This exponential experiment required 74 units (37 loaded with UO{sub 2} and 37 with UC) to simulate the Reactor fuel channels. Each unit was enclosed in a tube similar to the calandria ones. It contained the pressure tube, the shroud and the 19 rods cluster. Within the pressure tube, in touch with the elements, was the organic liquid. (Author)

  5. Etude Des Elements Culturels Dans “Cinq Villes” D’ahmet Hamdi Tanpinar: Intertextualité Et Interculturalité

    Directory of Open Access Journals (Sweden)

    Perihan YALÇIN

    2017-06-01

    Full Text Available L’objet du présent article est de préciser des idées et des observations à propos de la traduction en français l’une des oeuvres de la littérature turque. En tant que corpus, nous avons choisi le roman turc d’Ahmet Hamdi Tanpınar, célèbre poète et romancier turc qui a été considéré comme le fondateur de la littérature turque moderne. Son roman intitulé “Beş Şehir” a été traduit en français sous le titre de “Cinq Villes”. Il est évident que chaque langue contient, préfabrique, impose à ses locuteurs une certaine manière de regarder le monde, d’analyser l’expérience que nous avons du monde. Si nous voulons comprendre pourquoi et comment la traduction reste possible, il nous faut donc, d’abord, accepter dans son entièreté ce fait qu’une langue nous oblige à connaître d’autres cultures à voir le monde d’une certaine manière, la traduction n’est pas toujours possible. Elle ne l’est que dans une certaine mesure et dans certaines limites. G.Mounin(1976,44-45 souligne “pour bien traduire une langue, il ne suffit pas d’étudier cette langue, , il faut étudier, la culture qui lui correspond”. Notre objectif, dans ce travail, est d’analyser la traduction, plus particulièrement des éléments spécifiques propres à une culture inexistante dans la langue cible. Il s’agit de montrer comment un certain nombre de réferences historiques et culturelles sont traduits dans ce moyen d’expression. Nous traiterons en ce qui concerne les réferences culturelles qui doivent être adoptées par les connaissances des lecteurs français; et qui sont également fortes nombreuses dans cette oeuvre. Le traducteur doit expliquer au récepteur étranger, les particularités des termes ce qui lui sont compréhensibles et qu’il peut comparer avec les réalités déjà de la propre culture. Ces explications utilisées par le traducteur ont avant tout, une valeur informative, elles permettent aux r

  6. Capacity of the equipment family SICOM to inspect fuel elements; Capacidad de los equipos familia SICOM para inspeccionar elementos de combustible

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Siguero, A.; Sola, A.

    2013-07-01

    To check the status where the fuel assemblies are after has been operating in the core of nuclear plants, inspections have been conducted to carry out an improvement in the behavior of alloys used in pods of fuel, the control of corrosion of these pods because of heat, reducing the transfer of heat due to the oxide and with the support of visual inspections monitor the physical integrity of the fuel elements.

  7. Des racines et des ailes

    Directory of Open Access Journals (Sweden)

    Stéphanie Vincent-Geslin

    2012-05-01

    Full Text Available Les mobilités pendulaires semblent être en augmentation en Europe depuis une dizaine d’années. Cette croissance du temps passé à se déplacer amène à remettre en question la conjecture de Zahavi et apparaît relativement inexplicable en regard du paradigme classique de l’acteur rationnel traditionnellement utilisé dans le champ des transports. Si, dans la littérature, les temps de déplacements sont principalement expliqués par le contexte résidentiel, la forme urbaine et le travail, ce cadre explicatif ne dit rien des processus de décision eux-mêmes qui amènent aux pendularités intensives.À partir d’une enquête qualitative menée auprès de pendulaires français, suisses et belges, cette contribution propose d’analyser les arbitrages et les éléments déterminants des processus de la grande pendularité. Les mobilités quotidiennes pendulaires apparaissent comme le résultat de compromis entre activité professionnelle, attachement résidentiel et choix de vie et prennent ainsi la forme de stratégies de conciliation entre vie privée et vie professionnelle. Ces mobilités spatiales permettent alors paradoxalement la préservation des ancrages résidentiels, sociaux et familiaux.Roots and wings. Long-distance commuting patterns, or how to conciliate professional and personal lifeLong-distance commuting patterns appear to be increasing in Europe over the last ten years. These raising mobility patterns lead to reappraise the Zahavi conjecture and appear largely inexplicable by the classical rational actor paradigm traditionally used in transportation research. In literature, commuting is mainly explained by residential contexts, urban forms and job. Nevertheless this theoretical frame says little about the decision-making processes themselves. Based on a qualitative survey conducted in three European countries - France, Belgium and Switzerland – among a population of high commuters, this paper proposes an analysis of

  8. High Combustion Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — At NETL's High-Pressure Combustion Research Facility in Morgantown, WV, researchers can investigate new high-pressure, high-temperature hydrogen turbine combustion...

  9. Combustion Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Combustion Research Laboratory facilitates the development of new combustion systems or improves the operation of existing systems to meet the Army's mission for...

  10. Trace element analytics and multivariate statistics for investigation and assessment of the pollution situation in rivers; Elementspurenanalytik und multivariate Statistik zur Untersuchung und Bewertung des Belastungszustandes von Fliessgewaessern

    Energy Technology Data Exchange (ETDEWEB)

    Aulinger, A.M. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Kuestenforschung

    2002-07-01

    In order to describe and assess the element distribution and the trend of the pollution in sediments, particulate suspended matter and dissolved matter of the river Elbe more than 60 elements were determined in several sampling campaigns along the entire river during the nineties. By analyzing the resulting data with two- and multi-way principal components analysis geogenic and anthropogenically influenced elements were distinguished and typical longitudinal profiles concerning geogenic or anthropogenic characteristics were summarized. Sampling locations having similiar element distribution patterns were aggregated to characteristic Elbe sections by means of hierarchical cluster analysis. The temporal trend of the pollution within the different sections was quantified by comparing the mean concentrations of the anthropogenically influenced elements. Two- and Three-way PLS regression models were applied to predict element concentrations in one certain river compartment from measured concentrations in one or two different compartments. (orig.)

  11. Direct numerical simulation of two-phases turbulent combustion: application to study of propagation and structure of flames; Simulation numerique directe de la combustion turbulente diphasique: application a l'etude de la propagation et de la structure des flammes

    Energy Technology Data Exchange (ETDEWEB)

    Canneviere, K.

    2003-12-15

    This work is devoted to the study of the propagation and the structure of two-phases turbulent flames. To this end, Direct Numerical Simulations (DNS) are used. First, numerical systems for two-phases flow simulations is presented along with a specific chemical model. Then, a study of laminar spray flames is carried out. An analytical study related to the dynamics of evaporation of droplets is first proposed where the influence on the equivalence ratio of the ratio between the heating delay of the droplet and the evaporation delay is detailed. The simulation of a propagating flame through a cloud of droplets is carried out and a pulsating behavior is highlighted. A study of these flames according to the topology of liquid fuel enabled us to characterize a double flame structure composed of a premixed flame and a diffusion flame. Our last study is devoted to spray turbulent flames. Two-phase combustion of turbulent jets has been simulated. By varying the spray injection parameters (density, equivalence ratio), a database has been generated. This database allowed us to describe local and global flame regimes appearing in the combustion of sprays. They have been categorized in four main structures: open and closed external regime, group combustion and mixed combustion. Eventually, a combustion diagram has been developed. It involves the spray vaporization time, the mean inter-space between droplets or group of droplets and eventually the injected equivalence ratio. (author)

  12. The control of artificial radio-elements of medical use in France; Le controle des radioelements artificiels a usage medical en France

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Y. [Commissariat a l' energie atomique et aux energies alternatives - CEA, Centre d' etudes nucleaires de Saclay, Service des Radio-elements artificiels (France)

    1960-07-01

    Artificial radio-elements are sometimes used in hospitals or laboratories possessing specific equipment and certified staff. These radio-elements are produced within the Saclay Nuclear Centre, and, if they are aimed to a medical use, are submitted to a pharmaceutical control which the issue is addressed in this report. After a recall of the preparation of these radio-elements, the author describes physical controls (determination of radioactivity, measurement of colloidal particle size, impurity content), and biological controls performed on these radio-elements. Reprint of a paper published in Annales pharmaceutiques francaises, tom. XVII, p. 250-260, 1959.

  13. Combustion chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Brown, N.J. [Lawrence Berkeley Laboratory, CA (United States)

    1993-12-01

    This research is concerned with the development and use of sensitivity analysis tools to probe the response of dependent variables to model input variables. Sensitivity analysis is important at all levels of combustion modeling. This group`s research continues to be focused on elucidating the interrelationship between features in the underlying potential energy surface (obtained from ab initio quantum chemistry calculations) and their responses in the quantum dynamics, e.g., reactive transition probabilities, cross sections, and thermal rate coefficients. The goals of this research are: (i) to provide feedback information to quantum chemists in their potential surface refinement efforts, and (ii) to gain a better understanding of how various regions in the potential influence the dynamics. These investigations are carried out with the methodology of quantum functional sensitivity analysis (QFSA).

  14. Fuel elements assembling for the DON project exponential experience; Montaje de los elementos combustibles para la experiencia exponencial del proyecto DON

    Energy Technology Data Exchange (ETDEWEB)

    Anca Abati, R de

    1966-07-01

    It is described the fuel unit used in the DON exponential experience, the manufacturing installments and tools as well as the stages in the fabrication.These 74 elements contain each 19 cartridges loaded with synterized urania, uranium carbide and indium, gold, and manganese probes. They were arranged in calandria-like tubes and the process-tube. This last one containing a cooling liquid simulating the reactor organic. Besides being used in the DON reactor exponential experience they were used in critic essays by the substitution method in the French reactor AQUILON II. (Author) 6 refs.

  15. Certification of trace element contents (As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb and Zn) in a fly ash obtained from the combustion of pulverised coal

    International Nuclear Information System (INIS)

    Griepink, B.; Colinet, E.; Guzzi, G.; Haemers, L.; Muntau, H.

    1983-01-01

    The element contents of As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb and Zn of a fly ash from pulverised coal are certified. The procedures and their results for the homogenisation, the contamination and homogeneity checks and the analytical campaign are reported. The certified mass fractions and indicative values for Cr, Ni, Th, V and water soluble sulphate are given. The work was carried out within the framework of the activities of the Community Bureau of Reference (BCR) of the Commission of the European Communities. (orig.) [de

  16. Contribution to the study of influence of hydrodynamic conditions on the combustion of a preliminary mixture in a enclosed medium; Contribution a l`etude de l`influence des conditions hydrodynamiques sur la combustion d`un melange prealable dans un milieu confine

    Energy Technology Data Exchange (ETDEWEB)

    Henry, J.D.

    1996-02-01

    This thesis is a study on the internal combustion of a pistons engine. the first chapter is devoted to the description of the experimental device and measurement means. The combustion chamber is described with its adaptation to new experimental conditions. The second chapter concerns the diagnosis means to interpret the hydrodynamic conditions by the cross checking of displays with the measures of flow speed by laser velocimetry. The third chapter gives the result of analysis on the process of the birth of a turbulent flow in a whirl movement. The study of the electric spark and the initial phase of the combustion, in media with or without movement, is in the last chapter. (N.C.)

  17. Studies on the elements of optical and thermal energy transport through large components with transparent thermal insulation and shading; Untersuchungen der Grundlagen des optischen und thermischen Energietransportes bei grossflaechigen Komponenten mit transparenter Waermedaemmung und Verschattung

    Energy Technology Data Exchange (ETDEWEB)

    Platzer, W. [ed.; Apian-Bennewitz, P.; Kuhn, T.; Dill, F.U.; Wirth, H.; Wittwer, V.

    1997-11-28

    The report describes experimental and theoretical studies aiming at the comprehensive light-technical and energetic characterization of large, transparent construction elements including shading.- The two main measuring devices used for this purpose were a solar calorimeter for determining the total rate of energy passage, and a photogoniometer for measuring the bidirectional reflection and transmission properties of transparent construction elements and solar protection devices. The aims envisaged were to enhance measuring accuracy, create internationally comparable measuring conditions, and to integrate the experimental data into computer tools serving to evaluate construction elements in light-technical and energetic terms. (orig./GL) [Deutsch] In dem vorliegenden Sachbericht werden experimentelle und theoretische Arbeiten beschrieben, die auf eine umfassende lichttechnische und energetische Charakterisierung von grossflaechigen transparenten Bauteilen inklusive Sonnenschutz hinzielen. Die beiden wesentlichen Messvorrichtungen dazu sind ein Solarkalorimeter zur Bestimmung des Gesamtenergiedurchlassgrades und ein Photogoniometer zur Vermessung der bidirektionalen Reflexions- und Transmissionseigenschaften von transparenten Bauteilen und Sonnenschutzvorrichtungen. Ziele waren die Erhoehung der Messgenauigkeit, die Schaffung von international vergleichbaren Messbedingungen und die Integration der experimentellen Daten in Computerwerkzeuge, die der lichttechnischen und energetischen Bewertung von Bauteilen im Gebaeude dienen. (orig./GL)

  18. Neutron detection in an atomic reactor core using semi-conductors; Detection des neutrons par semi-conducteur dans un coeur de reacteur atomique

    Energy Technology Data Exchange (ETDEWEB)

    Divoux, F [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1968-07-01

    In this paper, the first part describes the principle of nuclear particle detection by means of semiconductor diodes and the general application of these. The second part describes fabrication of the device used to estimate thermic neutron fluxes in core of a swimming pool type reactor. The useful volume (2.9 mm thickness) is in the light water moderator, between combustible elements plates. The results, principally obtained in the core of Siloette reactor at the 'Centre d'Etudes Nucleaires de Grenoble' at low power, are mentioned in the third part. Flux maps have been set and comparison between converter's products: Bore 10, Lithium 6, Uranium 235 is made. (author) [French] Dans ce rapport, une premiere partie porte sur la description du principe de detection des particules nucleaires par diodes a semi-conducteur et sur l'application generale de celles-ci. Une deuxieme partie s'attache a decrire la fabrication du materiel utilise pour evaluer les flux de neutrons thermiques dans un coeur de reacteur type pile piscine. L'espace de mesure (2,9 mm d'epaisseur) se situe entre les plaques des elements combustibles, dans le moderateur eau legere. Les resultats, obtenus principalement dans le coeur du reacteur Siloette du Centre d'Etudes Nucleaires de Grenoble aux basses puissances de fonctionnement, sont rapportes dans la troisieme partie. Des cartes de flux ont ete dressees et une comparaison est faite entre les produits 'convertisseurs' suivants: Bore 10, Lithium 6, Uranium 235. (auteur)

  19. HERCULES Advanced Combustion Concepts Test Facility: Spray/Combustion Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, K. [Eidgenoessische Technische Hochschule (ETH), Labor fuer Aerothermochemie und Verbrennungssysteme, Zuerich (Switzerland)

    2004-07-01

    This yearly report for 2004 on behalf of the Swiss Federal Office of Energy (SFOE) at the Laboratory for Aero-thermochemistry and Combustion Systems at the Federal Institute of Technology ETH in Zurich, Switzerland, presents a review of work being done within the framework of HERCULES (High Efficiency R and D on Combustion with Ultra Low Emissions for Ships) - the international R and D project concerning new technologies for ships' diesels. The work involves the use and augmentation of simulation models. These are to be validated using experimental data. The report deals with the development of an experimental set-up that will simulate combustion in large two-stroke diesel engines and allow the generation of reference data. The main element of the test apparatus is a spray / combustion chamber with extensive possibilities for optical observation under variable flow conditions. The results of first simulations confirm concepts and shall help in further work on the project. The potential offered by high-speed camera systems was tested using the institute's existing HTDZ combustion chamber. Further work to be done is reviewed.

  20. DIAGNOSIS OF FAILURE OF COMBUSTION IN THE COMBUSTION CHAMBER WITH A THERMOVISION EQUIPMENT

    Directory of Open Access Journals (Sweden)

    S. V. Vorobiev

    2014-01-01

    Full Text Available The use of thermovision technology to diagnose failure of the combustion flame test tube of the main combustion chamber gas turbine engine is deal with in the article. Join the thermal radiation of the jet of combustion products and the internal elements was carried out using short-wave thermovision system AGA-782 with spectral spectral filters in several ranges from 3.2 to 5.6 microns. Thermovision is mounted on the axis of the flame tube. The output signal was recorded and processed on a computer in real time, allowing monitor the combustion process and the thermal state of the object during the experiment.

  1. Professional Nuclear Materials Management; Gestion Industrielle des Matieres Nucleaires; Obrashchenie s yadernymi materialami na professional'nom urovne; Administracion Eficiente de Materiales Nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Forcella, A. A.; O' Leary, W. J. [Allis-Chalmers Manufacturing Company, Bethesda, MD (United States)

    1966-02-15

    . (author) [French] Le memoire expose en quoi consiste la gestion des matieres nucleaires dans une centrale nucleaire type, aux Etats-Unis. Comme le reacteur en question est partiellement finance a l'aide de capitaux prives, l'une des principales obligations de l'exploitant est d'assurer la protection et la rentabilite des investissements. Etant donne que les matieres nucleaires sont d'une valeur intrinseque elevee, il faut constamment proceder a des controles appropries allant au-dela des mesures de securite et de la comptabilite interessant les matieresnucleaires proprement dites afin de reduire les pertes au minimum. Il faut faire preuve de clairvoyance et planifier judicieusement pour prevenir toute perte supplementaire de capital provenant de frais inutiles ou d'un manque a gagner dans divers secteurs de l'exploitation. C'est ainsi que le gestionnaire de matieres nucleaires doit prendre des dispositions pour garantir la bonne marche des operations et assurer le respect des plans d'execution par une liaison et un controle constants, dans les domaines suivants? a) acquisition du combustible et des elements combustibles, b) utilisation des elements combustibles dans le reacteur et c) recuperation, dans le combustible irradie, des produits et matieres presentant de l'interet. Pendant la periode qui precede l'utilisation du reacteur, il faut faire une place importante dans la planification et les travaux preparatoires aux considerations d'economie dans la conception des elements combustibles, en ce qui concerne leur fabrication, leur manutention, leur transport et leur remplacement. Les differentes etapes de la fabrication doivent etre planifiees de facon a reduire au minimum le manque a gagner du a des periodes improductives d'entreposage de matieres tres couteuses. Pendant la marche du reacteur, il faut assurer une combustion maximale de la matiere fissile par des redistributions appropriees du combustible dans le coeur du reacteur. Parallelement, les temps morts dus a

  2. Measurements of gas and volatile element production rates from an irradiated molten lead and lead-bismuth spallation target with proton beams of 1 and 1.4 GeV; Mesures de taux de production d'elements gazeux et volatiles lors de reactions induites par des protons de 1 et 1,4 GeV sur des cibles epaisses de plomb et plomb-bismuth liquides

    Energy Technology Data Exchange (ETDEWEB)

    Tall, Y

    2008-03-15

    The integrated project EUROTRANS (European Research Programme for the Transmutation of High Level Nuclear Waste in an Accelerator Driven System) of the 6. EURATOM Framework Programme aims to demonstrate the transmutation of radioactive waste in ADS (Accelerator Driven Sub-critical system). It will carry out a first advanced design of an experimental facility to demonstrate the technical feasibility of transmutation, and will produce a conceptual design of an industrial facility dedicated to transmutation. An ADS consists of three fundamental elements: the accelerator of protons, the sub-critical core and the spallation target. SUBATECH (physique Sub-Atomique et des Technologies associees) laboratory is involved to the study of the chosen liquid lead-bismuth as a spallation ADS target. The irradiation of liquid lead-bismuth target with energetic proton beam generates in addition to neutrons, volatile and radioactive residues. In order to determine experimentally the production rates of gas and volatile elements following a spallation reaction in a lead-bismuth target, the experiment IS419 was performed at the ISOLDE facility at CERN (Centre Europeen de la Recherche Nucleaire). This experiment constitutes the frame of the thesis whose main objective is to assess and study the production and release rates of many gas and volatile element from the irradiated lead-bismuth target with an energetic proton beam. The obtained data are compared to Monte Carlo simulation code (MCNPX) results in order to test the intranuclear cascade model of Bertini and of Cugnon, and the evaporation options of Dresner and Schmidt. (author)

  3. Study of thermodynamic properties of binary and ternary liquid alloys of aluminium with the elements iron, cobalt, nickel and oxygen; Etude des proprietes thermodynamiques des alliages liquides binaires et ternaires de l'aluminium avec les elements fer, cobalt, nickel et l'oxygene

    Energy Technology Data Exchange (ETDEWEB)

    Vachet, F [CEA Vallee du Rhone, 26-Pierrelatte (France)

    1966-07-01

    The present work deals with the thermodynamic study of aluminium liquid alloys with the metals iron, cobalt and nickel. The experiments carried out lead to the activity, at 1600 deg C, of aluminium in the (Al, Fe), (Al, Co), (Al, Ni) liquid alloys. The experimental method used consists in studying the partition of aluminium between the liquid immiscible phases made up with the pairs of metals (Fe, Ag), (Co, Ag), (Ni, Ag). The informations so obtained are used for drawing the isothermal equilibrium phases diagrams sections of (Al, Fe, Ag), (Al, Co, Ag), (Al, Ni, Ag) systems. The study of the partition of silver between lead and aluminium joined with the determinations of several authors allows us to determine the aluminium activity, analytically presented, in the metal M (iron cobalt and nickel). The Wagner's interaction parameters of aluminium in metal M are determined. The results obtained as the equilibrium phases diagrams of (Al, M) systems allow to compare the thermodynamic properties of the Al Fe system in liquid and solid states and to estimate the enthalpies of melting of the AlCo and AlNi intermetallic compounds. The activity, at 1600 deg C, of aluminium in (Al, Fe, Co), (Al, Fe, Ni), (Al, Co, Ni) liquid alloys is estimated through thermodynamic properties of binary components systems by application of several methods leading to results in good agreement. The study of aluminium-oxygen interactions in the liquid metallic solvants M allows us to propose an explanation for the shape of the deoxidation equilibrium line of iron, cobalt and nickel by aluminium and to compare the de-oxidizing power of aluminium toward iron, cobalt and nickel oxides. (author) [French] Le travail presente se rapporte a l'etude thermodynamique des alliages liquides de l'aluminium avec les metaux fer, cobalt et nickel. Les experiences effectuees ont pour but de determiner l'activite, a 1600 C, de l'aluminium dans les alliages liquides (Al, Fe), (Al, Co), (Al, Ni). La methode

  4. Rotary combustion device

    NARCIS (Netherlands)

    2008-01-01

    Rotary combustion device (1) with rotary combustion chamber (4). Specific measures are taken to provide ignition of a combustible mixture. It is proposed that a hollow tube be provided coaxially with the axis of rotation (6), so that a small part of the mixture is guided into the combustion chamber.

  5. Utilisation de produits organiques oxygénés comme carburants et combustibles dans les moteurs. Deuxième partie : Les différentes filières d'obtention des carburols. Analyse technico-économique Using Oxygenated Organic Products As Fuels in Engines. Part Two: Different Systems for Producing Alcohol Fuels. Technico-Economic Analysis

    Directory of Open Access Journals (Sweden)

    Chauvel A.

    2006-11-01

    Full Text Available Parmi les produits à même d'être substitués aux hydrocarbures pour la constitution des carburants, les composés organiques oxygénés occupent une place prépondérante à cause de leurs caractéristiques favorables à la combustion dans les moteurs, qu'ils soient employés purs ou mélangés (seuls ou à plusieurs aux hydrocarbures, constituants des carburants classiques. Dans cet article, ces composés oxygénés sont désignés sous le nom de carburols. Alors que l'objet de la première partie de l'étude a été d'examiner les conséquences techniques de l'emploi de ces produits sur les circuits de distribution et le fonctionnement des véhicules, il s'agit dans la présente partie d'analyser les caractéristiques technico-économiques de leur fabrication. En particulier, on y aborde successivement les points suivants : - disponibilités en matières premières : ressources fossiles et végétales ; - analyse technique des divers modes d'obtention - analyse économique ; - programmes nationaux. Among products that can be substituted for hydrocarbons for producing fuels, oxygenated organic compounds occupy a preponderant position because of their favorable characteristics for combustion in engines whether they are used in a pure form or in mixtures (alone or severally with hydrocarbons which are used to make up conventional fuels. In this article these oxygenated compounds are given the name carburols (alcohol fuels. Whereas the aim of Part 1 was to examine the technical consequences of using such products in distribution circuits and for vehicle operating, Part 2 is an analysis of the technico-economic aspects of manufacturing them. In particular, the following points are taken up successively: (a availabilities of raw materials. fossil and vegetebal resources; (b technical analysis of various production methods; (c economic analysis; (d national programs. Depending on the amounts involved, a distinction is made among alternative

  6. Modeling of the water gap in BWR fuel elements using SCALE/TRITON; Modellierung des Wasserspalts bei SWR-BE mit SCALE/TRITON

    Energy Technology Data Exchange (ETDEWEB)

    Tittelbach, S.; Chernykh, M. [WTI Wissenschaftlich-Technische Ingenieurberatung GmbH, Juelich (Germany)

    2012-11-01

    The authors show that an adequate modeling of the water gap in BWR fuel element models using the code TRITON requires an explicit consideration of the Dancoff factors. The analysis of three modeling options reveals that considering the moderating effects of the water gap coolant for the peripheral fuel elements the resulting deviations of the U-235 and Pu-239 concentrations are significantly reduced. The increased temporal calculation efforts are justified with respect to the burnup credits for criticality safety analyses.

  7. Comparison of Elemental Mercury Oxidation Across Vanadium and Cerium Based Catalysts in Coal Combustion Flue Gas: Catalytic Performances and Particulate Matter Effects.

    Science.gov (United States)

    Wan, Qi; Yao, Qiang; Duan, Lei; Li, Xinghua; Zhang, Lei; Hao, Jiming

    2018-03-06

    This paper discussed the field test results of mercury oxidation activities over vanadium and cerium based catalysts in both coal-fired circulating fluidized bed boiler (CFBB) and chain grate boiler (CGB) flue gases. The characterizations of the catalysts and effects of flue gas components, specifically the particulate matter (PM) species, were also discussed. The catalytic performance results indicated that both catalysts exhibited mercury oxidation preference in CGB flue gas rather than in CFBB flue gas. Flue gas component studies before and after dust removal equipment implied that the mercury oxidation was well related to PM, together with gaseous components such as NO, SO 2 , and NH 3 . Further investigations demonstrated a negative PM concentration-induced effect on the mercury oxidation activity in the flue gases before the dust removal, which was attributed to the surface coverage by the large amount of PM. In addition, the PM concentrations in the flue gases after the dust removal failed in determining the mercury oxidation efficiency, wherein the presence of different chemical species in PM, such as elemental carbon (EC), organic carbon (OC) and alkali (earth) metals (Na, Mg, K, and Ca) in the flue gases dominated the catalytic oxidation of mercury.

  8. 3 and 4 oxidation state element solubilities in borosilicate glasses. Implement to actinides in nuclear glasses; Solubilite des elements aux degres d'oxydation (3) et (4) dans les verres de borosilicate. Application aux actinides dans les verres nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Cachia, J.N

    2005-12-15

    In order to ensure optimal radionuclides containment, the knowledge of the actinide loading limits in nuclear waste glasses and also the comprehension of the solubilization mechanisms of these elements are essential. A first part of this manuscript deals with the study of the differences in solubility of the tri and tetravalent elements (actinides and surrogates) particularly in function of the melting temperature. The results obtained indicate that trivalent elements (La, Gd, Nd, Am, Cm) exhibit a higher solubility than tetravalent elements (Hf, Th, Pu). Consequently, it was planned to reduce plutonium at the oxidation state (III), the later being essentially tetravalent in borosilicate glasses. An innovating reduction process of multi-valent elements (cerium, plutonium) using silicon nitride has been developed in a second part of this work. Reduced plutonium-bearing glasses synthesized by Si{sub 3}N{sub 4} addition made it possible to double the plutonium solubility from 2 to 4 wt% at 1200 deg C. A structural approach to investigate the differences between tri and tetravalent elements was finally undertaken. These investigations were carried out by X-rays Absorption Spectroscopy (EXAFS) and NMR. Trivalent rare earth and actinide elements seem to behave as network modifiers while tetravalent elements rather present true intermediaries' behaviour. (author)

  9. Developments in natural uranium - graphite reactors; Developpement des reacteurs a graphite et uranium naturel

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Saitcevsky, B [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    in order to show the advantages resulting from such developments in gas-graphite natural metallic uranium reactor systems; these are: a doubling of the specific and volume powers, and a three-fold reduction in the number of channels. The research now under way will make it possible to calculate the reduction in capital costs which will result from these important technical advances. (authors) [French] Le programme francais de centrales a graphite et uranium naturel s'est developpe, d'EDF 1 a EDF 4 - dans la voie d'un accroissement de la puissance unitaire des installations, de la puissance specifique et de la puissance volumique, et d'une amelioration des conditions de securite de fonctionnement. La puissance elevee d'EDF 4 (500 MWe) et l'integration du circuit primaire dans le caisson, lui-meme en beton precontraint, permettent ainsi de tirer le meilleur parti des elements combustibles tubulaires utilises des EDF 1, et d'arriver ainsi a une solution tres satisfaisante. L'emploi d'un element combustible refroidi interieurement (element annulaire) permet de faire un nouveau pas en avant: il devient alors possible d'augmenter la pression du gaz de refroidissement sans craindre le fluage du tube d'uranium. L'emploi d'un caisson en beton precontraint permet une telle augmentation de pression, et l'integration du circuit primaire elimine les risques d'une depressurisation rapide qui aurait presente dans ce cas un risque majeur. On aborde dans ce rapport les principaux problemes poses par ce nouveau type de centrale et on indique les grandes lignes des recherches et etudes effectuees en France: - Les etudes de neutronique et thermique ont permis d'envisager l'emploi d'elements combustibles de grandes dimensions (diametre interne = 77 mm, diametre externe = 95 mm), tout en conservant l'uranium naturel. - Les problemes de fabrication de ces elements, et de leur comportement en pile, font l'objet d'un programme important, tant hors pile que dans les piles de puissance (EDF 2

  10. Developments in natural uranium - graphite reactors; Developpement des reacteurs a graphite et uranium naturel

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Saitcevsky, B. [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    in order to show the advantages resulting from such developments in gas-graphite natural metallic uranium reactor systems; these are: a doubling of the specific and volume powers, and a three-fold reduction in the number of channels. The research now under way will make it possible to calculate the reduction in capital costs which will result from these important technical advances. (authors) [French] Le programme francais de centrales a graphite et uranium naturel s'est developpe, d'EDF 1 a EDF 4 - dans la voie d'un accroissement de la puissance unitaire des installations, de la puissance specifique et de la puissance volumique, et d'une amelioration des conditions de securite de fonctionnement. La puissance elevee d'EDF 4 (500 MWe) et l'integration du circuit primaire dans le caisson, lui-meme en beton precontraint, permettent ainsi de tirer le meilleur parti des elements combustibles tubulaires utilises des EDF 1, et d'arriver ainsi a une solution tres satisfaisante. L'emploi d'un element combustible refroidi interieurement (element annulaire) permet de faire un nouveau pas en avant: il devient alors possible d'augmenter la pression du gaz de refroidissement sans craindre le fluage du tube d'uranium. L'emploi d'un caisson en beton precontraint permet une telle augmentation de pression, et l'integration du circuit primaire elimine les risques d'une depressurisation rapide qui aurait presente dans ce cas un risque majeur. On aborde dans ce rapport les principaux problemes poses par ce nouveau type de centrale et on indique les grandes lignes des recherches et etudes effectuees en France: - Les etudes de neutronique et thermique ont permis d'envisager l'emploi d'elements combustibles de grandes dimensions (diametre interne = 77 mm, diametre externe = 95 mm), tout en conservant l'uranium naturel. - Les problemes de fabrication de ces elements, et de leur comportement en pile

  11. Thermomechanical evaluation of BWR fuel elements for procedures of preconditioned with FEMAXI-V; Evaluacion termomecanica de elementos combustible BWR para procedimientos de preacondicionado con FEMAXI-V

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez L, H.; Lucatero, M.A.; Ortiz V, J. [ININ, Carretera Mexico-Toluca Km 36.5, La Marquesa, Estado de Mexico (Mexico)]. e-mail: hhl@nuclear.inin.mx

    2006-07-01

    The limitations in the burnt of the nuclear fuel usually are fixed by the one limit in the efforts to that undergo them the components of a nuclear fuel assembly. The limits defined its provide the direction to the fuel designer to reduce to the minimum the fuel failure during the operation, and they also prevent against some thermomechanical phenomena that could happen during the evolution of transitory events. Particularly, a limit value of LHGR is fixed to consider those physical phenomena that could lead to the interaction of the pellet-shirt (Pellet Cladding Interaction, PCI). This limit value it is related directly with an PCI limit that can be fixed based on experimental tests of power ramps. This way, to avoid to violate the PCI limit, the conditioning procedures of the fuel are still required for fuel elements with and without barrier. Those simulation procedures of the power ramp are carried out for the reactor operator during the starting maneuvers or of power increase like preventive measure of possible consequences in the thermomechanical behavior of the fuel. In this work, the thermomechanical behavior of two different types of fuel rods of the boiling water reactor is analyzed during the pursuit of the procedures of fuel preconditioning. Five diverse preconditioning calculations were carried out, each one with three diverse linear ramps of power increments. The starting point of the ramps was taken of the data of the cycle 8 of the unit 1 of the Laguna Verde Nucleo electric Central. The superior limit superior of the ramps it was the threshold of the lineal power in which a fuel failure could be presented by PCI, in function of the fuel burnt. The analysis was carried out with the FEMAXI-V code. (Author)

  12. Fission gas pressure build-up and fast-breeder economy; Accumulation de la pression des gaz de fission et economie des reacteurs surgenerateurs a neutrons rapides; Nakoplenie davleniya gazov produktov deleniya i ehkonomika reaktorov-razmnozhitelej na bystrykh nejtronakh; Aumento de la presion de los gases de fision y economia de los reactores reproductores rapidos

    Energy Technology Data Exchange (ETDEWEB)

    Engelmann, P [Kernforschungszentrum, Karlsruhe (Germany)

    1962-03-15

    Fuel-cycle costs and doubling time of fast-breeder reactors are strongly affected by the fuel-burn-up obtainable. Use of oxide or carbide fuel offers the possibility of reaching a burn-up of 100 000 MWd/t. In fuel-clad elements, a limiting factor is the fission-gas-pressure build-up. At the high burn-up considered, an appreciable fraction of the fission gases gets into the pores and thus contributes to the pressure on the can. Starting from the known fission-product yields and decay chains, gas production and pressure build-up have been calculated. Three physical models have been employed in calculating the pressure acting upon the can : the gas is contained either in interconnected pores, in separate pores, or in a central hole. The pressure-dependence upon free volume (fuel density) and temperature will be discussed. Cans made of high-strength materials as Ineonel-X and molybdenum could stand the fission-gas pressure at operating temperatures. Unfortunately, these materials have higher absorption cross-sections than stainless steel. Results of a multi-group calculation are given, showing the effect of using these can materials and of decreasing the fuel density on critical mass and breeding ratio in small and medium-size breeders. (author) [French] Le cout du cycle de combustible et la periode de doublement des reacteurs surgenerateurs a neutrons rapides dependent etroitement du taux de combustion. En utilisant pour combustible un oxyde ou un carbure, on peut atteindre un taux de combustion de 100 000 MW j/t. Avec des combustibles gaines, l'accumulation de la pression des gaz de fission est un facteur limitatif. Pour le fort taux de combustion envisage, une fraction non negligeable des gaz de fission penetre dans les interstices et contribue ainsi a la pression sur la gaine. A partir des rendements en produits de fission et des chaines de desintegration connus, l'auteur a calcule la production de gaz et l'accumulation de pression. Pour calculer la pression

  13. Combustion 2000

    Energy Technology Data Exchange (ETDEWEB)

    A. Levasseur; S. Goodstine; J. Ruby; M. Nawaz; C. Senior; F. Robson; S. Lehman; W. Blecher; W. Fugard; A. Rao; A. Sarofim; P. Smith; D. Pershing; E. Eddings; M. Cremer; J. Hurley; G. Weber; M. Jones; M. Collings; D. Hajicek; A. Henderson; P. Klevan; D. Seery; B. Knight; R. Lessard; J. Sangiovanni; A. Dennis; C. Bird; W. Sutton; N. Bornstein; F. Cogswell; C. Randino; S. Gale; Mike Heap

    2001-06-30

    . To achieve these objectives requires a change from complete reliance of coal-fired systems on steam turbines (Rankine cycles) and moving forward to a combined cycle utilizing gas turbines (Brayton cycles) which offer the possibility of significantly greater efficiency. This is because gas turbine cycles operate at temperatures well beyond current steam cycles, allowing the working fluid (air) temperature to more closely approach that of the major energy source, the combustion of coal. In fact, a good figure of merit for a HIPPS design is just how much of the enthalpy from coal combustion is used by the gas turbine. The efficiency of a power cycle varies directly with the temperature of the working fluid and for contemporary gas turbines the optimal turbine inlet temperature is in the range of 2300-2500 F (1260-1371 C). These temperatures are beyond the working range of currently available alloys and are also in the range of the ash fusion temperature of most coals. These two sets of physical properties combine to produce the major engineering challenges for a HIPPS design. The UTRC team developed a design hierarchy to impose more rigor in our approach. Once the size of the plant had been determined by the choice of gas turbine and the matching steam turbine, the design process of the High Temperature Advanced Furnace (HITAF) moved ineluctably to a down-fired, slagging configuration. This design was based on two air heaters: one a high temperature slagging Radiative Air Heater (RAH) and a lower temperature, dry ash Convective Air Heater (CAH). The specific details of the air heaters are arrived at by an iterative sequence in the following order:-Starting from the overall Cycle requirements which set the limits for the combustion and heat transfer analysis-The available enthalpy determined the range of materials, ceramics or alloys, which could tolerate the temperatures-Structural Analysis of the designs proved to be the major limitation-Finally the commercialization

  14. The functioning of the reactors G2-G3 at Marcoule and E.D.F. 1; Experience de fonctionnement des reacteurs G2-G3 de Marcoule et enseignements des essais de demarrage du reacteur E.D.F. 1 de Chinon

    Energy Technology Data Exchange (ETDEWEB)

    Boussard, R; Conte, F [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires; Stolz, J M [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    After resuming briefly the characteristics of the installations G2-G3 at Marcoule and EDF 1 at Chinon, the authors review the main aspects of the tests, the starting and the exploitation of these reactors. Among the various points examined, particular emphasis is given to the devices of original nature such as tubular fuel elements, flattening of the neutron flux by stuffing, behaviour of the reactor tanks and the cooling circuits, the blowers, unloading devices, regulation and functioning of the informations. This analysis deals equally with the performances obtained and the difficulties and the various incidents experienced during the initial starting period. Among the more interesting results, the progressive increase in the power of the Marcoule reactors is mentioned, obtained through a better knowledge of the parameters covering the functioning of the reactors such as the distribution of the flux and the temperatures etc... acquired during the course of the exploitation of the reactor. The conclusion reached by the authors is that the experience gained on these installations has shown: - that during an initial period, adjustments became necessary, all of which turned out to be possible, - that an analysis of their functioning has permitted the progressive movement towards a truly industrial exploitation. (authors) [French] Les auteurs, apres un bref rappel des caracteristiques des installations G2 - G3 de MARCOULE et E.D.F. 1 de CHINON, passent en revue les principaux aspects des essais, de la mise en service et de l'exploitation de ces centrales. Parmi les divers points examines, une attention speciale est accordee aux dispositifs presentant un caractere original tels que elements combustibles tubulaires, aplatissement du flux neutronique par gavage, comportement des caissons des reacteurs et des circuits de refroidissement, soufflantes, appareils de dechargement, regulation et fonctionnement des informations. L'analyse presentee porte tant sur les

  15. The role of the fuel injection system for combustion process optimization of highly turbocharged PC diesel engines; Die Rolle des Einspritzsystems bei der Brennverfahrensoptimierung von hochaufgeladenen Pkw-Dieselmotoren

    Energy Technology Data Exchange (ETDEWEB)

    Gerhardt, Juergen; Leonhard, Rolf; Krueger, Michael; Naber, Dirk; Pitt, J. [Robert Bosch GmbH, Stuttgart (Germany)

    2008-07-01

    In order to comply with continuously rising requirements from emission legislation and fuel economy enhancement, modern Diesel engines for passenger cars still offer a variety of measures. Focus of this paper is the importance of a highly flexible fuel-injection system and an optimized injection strategy as direct measures to improve both, tail-pipe emission as well as vehicle fuel economy. An integrated system approach of high pressure pump, injector and nozzle provides the latest injection patterns combined with an increased rail pressure level with a best-in-class hydraulic efficiency. The resulting improvement in the injection system and thus in the combustion also enables the introduction of additional indirect, very effective measures for fuel consumption reduction, such as downsizing and downspeeding. In order to fully utilize the potent of the mentioned approaches, the application of advanced boosting technology is an additional key factor. Bosch Diesel injection technology and optimized combustion systems pave the way to achieve the goal of efficient emission reduction. (orig.)

  16. The general formulation and practical calculation of the diffusion coefficient in a lattice containing cavities; Formulation generale et calcul pratique du coefficient de diffusion dans un reseau comportant des cavites

    Energy Technology Data Exchange (ETDEWEB)

    Benoist, P [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    The calculation of diffusion coefficients in a lattice necessitates the knowledge of a correct method of weighting the free paths of the different constituents. An unambiguous definition of this weighting method is given here, based on the calculation of leakages from a zone of a reactor. The formulation obtained, which is both simple and general, reduces the calculation of diffusion coefficients to that of collision probabilities in the different media; it reveals in the expression for the radial coefficient the series of the terms of angular correlation (cross terms) recently shown by several authors. This formulation is then used to calculate the practical case of a classical type of lattice composed of a moderator and a fuel element surrounded by an empty space. Analytical and numerical comparison of the expressions obtained with those inferred from the theory of BEHRENS shows up the importance of several new terms some of which are linked with the transparency of the fuel element. Cross terms up to the second order are evaluated. A practical formulary is given at the end of the paper. (author) [French] Le calcul des coefficients de diffusion dans un reseau suppose la connaissance d'un mode de ponderation correct des libres parcours des differents constituants. On definit ici sans ambiguite ce mode de ponderation a partir du calcul des fuites hors d'une zone de reacteur. La formulation obtenue, simple et generale, ramene le calcul des coefficients de diffusion a celui des probabilites de collision dans les differents milieux; elle fait apparaitre dans l'expression du coefficient radial la serie des termes de correlation angulaire (termes rectangles), mis en evidence recemment par plusieurs auteurs. Cette formulation est ensuite appliquee au calcul pratique d'un reseau classique, compose d'un moderateur et d'un element combustible entoure d'une cavite; la comparaison analytique et numerique des expressions obtenues avec celles deduites de la theorie de BEHRENS

  17. Reduced NOX combustion method

    International Nuclear Information System (INIS)

    Delano, M.A.

    1991-01-01

    This patent describes a method for combusting fuel and oxidant to achieve reduced formation of nitrogen oxides. It comprises: It comprises: heating a combustion zone to a temperature at least equal to 1500 degrees F.; injecting into the heated combustion zone a stream of oxidant at a velocity within the range of from 200 to 1070 feet per second; injecting into the combustion zone, spaced from the oxidant stream, a fuel stream at a velocity such that the ratio of oxidant stream velocity to fuel stream velocity does not exceed 20; aspirating combustion gases into the oxidant stream and thereafter intermixing the aspirated oxidant stream and fuel stream to form a combustible mixture; combusting the combustible mixture to produce combustion gases for the aspiration; and maintaining the fuel stream substantially free from contact with oxidant prior to the intermixture with aspirated oxidant

  18. Quantitative analysis of fission products by {gamma} spectrography; Analyse quantitative des produits de fission par spectrographie {gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Malet, G

    1962-07-01

    The activity of the fission products present in treated solutions of irradiated fuels is given as a function of the time of cooling and of the irradiation time. The variation of the ratio ({sup 144}Ce + {sup 144}Pr activity/{sup 137}Cs activity) as a function of these same parameters is also given. From these results a method is deduced giving the 'age' of the solution analyzed. By {gamma}-scintillation spectrography it was possible to estimate the following elements individually: {sup 141}Ce, {sup 144}Ce + {sup 144}Pr, {sup 103}Ru, {sup 106}Ru + {sup 106}Rh, {sup 137}Cs, {sup 95}Zr + {sup 95}Nb. Yield curves are given for the case of a single emitter. Of the various existing methods, that of the least squares was used for the quantitative analysis of the afore-mentioned fission products. The accuracy attained varies from 3 to 10%. (author) [French] L'activite des produits de fission presents dans les solutions de traitement de combustibles irradies est donnee en fonction du temps de refroidissement et du temps d'irradiation. On etudie de plus la variation du rapport Activite du {sup 144}Ce + {sup 144}Pr /Activite du {sup 137}Cs en fonction de ces memes parametres. De ces resultats, on deduit une methode donnant l'age de la solution analysee. La spectrographie {gamma} a scintillation a permis le dosage individuel des produits suivants: {sup 141}Ce, {sup 144}Ce + {sup 144}Pr, {sup 103}Ru, {sup 106}Ru + {sup 106}Rh, {sup 137}Cs, {sup 95}Zr + {sup 95}Nb. Des courbes de rendement sont donnees dans le cas d'un emetteur unique. Des differentes methodes existantes, la methode des moindres carres a ete employee pour l'analyse quantitative des produits de fission precites. La precision obtenue varie entre 3 et 10 pour cent. (auteur)

  19. Radio-protection problems presented by iodine isotopes in nuclear fuel chemical treatment plants (1962); Les problemes de radioprotection poses par les isotopes de l'iode dans les installations de traitement chimique des combustibles (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Bouzigues, H; Scheidhauer, J; Messainguiral, L [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

    1962-07-01

    The origin of radio-iodine and the conditions in which it is liberated are given. The authors review the question of the risks associated with the presence of this radioelement In the atmosphere. Finally a method is proposed for the trapping and rapid measuring of the iodine in the vapour form, applicable to radioprotection. (authors) [French] L'origine et les conditions de liberation du radioiode sont exposees. Les auteurs font le point de la question des risques associes a la presence de ce radioelement dans l'atmosphere. Enfin, une methode de piegeage et de mesure rapide de l'iode a l'etat de vapeur applicable a la radioprotection, est proposee. (auteurs)

  20. Studies of the source complex behaviour and of the ultrasound radiation of contact flexible multi-element transducers; Etudes du comportement complexe de source et du rayonnement ultrasonore des traducteurs multi-elements flexibles au contact

    Energy Technology Data Exchange (ETDEWEB)

    Amory, V

    2007-12-15

    This work deals with the ultrasonic nondestructive testing of parts with complex geometries using soft multi-element sensors. The different types of contact control configurations are presented first. Then, the difficulties encountered with conventional contact transducers are explained and the multi-element piezoelectric transducers technology, developed to meet these difficulties, is presented. The second chapter presents the results of finite-element calculations showing the complexity of a transducer in a condition of testing utilization. In a same configuration, the radiated far field calculated by finite-elements is compared to the measurement in order to validate the way the source behaviour is calculated. However, despite the efficiency of the finite-elements simulation, this tool is numerically too costly and cannot be used to optimize a full multi-element transducer. Therefore, a realistic source model is built and implemented in a radiation code based on high-frequency asymptotic approximations where only L and T volume waves are calculated. The incapacity of this model to reproduce the behaviour of T waves in some directions of propagation has led to give a particular attention to the fore-waves, neglected in the radiation calculation. Chapter 3 treats of the building of an exact radiation model taking into consideration the fore-waves contribution emitted by a contact transducer exerting a random space-time distribution constraint at the surface of the considered medium. A radiation model, based on the calculation of exact Green functions of the Lamb problem is proposed. The exact model is particularly interesting in the case of sensor geometries with a long length with respect to other dimensions (2D case). Field calculation results are shown for an element of the matrix network (3D case) and for a linear element (2D case). A study of different existing approached models is carried out as well. The last chapter presents some results of the field

  1. Combustion instability modeling and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States); Sheppard, E.J. [Tuskeggee Univ., Tuskegee, AL (United States). Dept. of Aerospace Engineering

    1995-12-31

    It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors. The present study represents a coordinated effort between industry, government and academia to investigate gas turbine combustion dynamics. Specific study areas include development of advanced diagnostics, definition of controlling phenomena, advancement of analytical and numerical modeling capabilities, and assessment of the current status of our ability to apply these tools to practical gas turbine combustors. The present work involves four tasks which address, respectively, (1) the development of a fiber-optic probe for fuel-air ratio measurements, (2) the study of combustion instability using laser-based diagnostics in a high pressure, high temperature flow reactor, (3) the development of analytical and numerical modeling capabilities for describing combustion instability which will be validated against experimental data, and (4) the preparation of a literature survey and establishment of a data base on practical experience with combustion instability.

  2. Power Split Strategy for Fuel Cell Hybrid Electric System Stratégie de séparation des flux de puissance pour un système électrique hybride à pile à combustible

    Directory of Open Access Journals (Sweden)

    Di Domenico D.

    2009-11-01

    Full Text Available The power management of a hybrid system composed of a fuel cell, a battery and a DC/DC power converter is developed. A decoupled control strategy is proposed, aimed at balancing the power flow between the stack and the battery and avoiding electrochemical damage due to low oxygen concentration in the fuel cell cathode. The controller is composed of two components. The first controller regulates the compressor, and as a consequence the oxygen supplied to the cathode, via a classic Proportional-Integral controller. The second controller optimally manages the current demanded by the fuel cell and battery via a linear-quadratic control strategy acting on the converter. An Extended Kalman Filter is also designed in order to estimate the battery State of Charge. The closed-loop performance was tested in simulation using a 310th-order system model. Ce papier illustre une stratégie de gestion de puissance pour un système hybride composé d’une pile à combustible, d’une batterie et d’un convertisseur DC/DC. Dans le but d’équilibrer les flux de puissance entre la pile à combustible et la batterie et d’éviter les dégâts causés par une dépression d’oxygène dans le cathode de la pile, un contrôleur découplé est proposé. Ce contrôleur se compose de deux parties. La première, un régulateur proportionnel-intégral, commande le compresseur et, par conséquent, le flux d’oxygène fourni au cathode. La deuxième, un régulateur linéaire-quadratique, gère le courant demandé par la pile à combustible et la batterie. Pour estimer l’état de charge de la batterie, un filtre de Kalman étendu a aussi été conçu. Les performances de la stratégie ont été analysées en simulation avec un modèle de batterie du 310e ordre.

  3. Étude économique des foyers domestiques par la technique d ...

    African Journals Online (AJOL)

    Les foyers font partie de la vie courante. Chaque ménage en utilise pour la cuisson de ses repas. Dans les pays en développement, la plupart des populations utilisent surtout des foyers à combustibles ligneux. Les effets négatifs sur l'environnement sont aujourd'hui bien connus : poches de désertification, érosion des sols, ...

  4. The Role of Non-Destructive Testing in Test-Reactor Operation at the National Reactor Testing Station; Role des Essais Non Destructifs dans l'Exploitation des Reacteurs d'Essai au Centre National d'Essais de Reacteurs; Rol' nedestruktivnykh ispytanij pri ehkspluatatsii ispytatel'nykh reaktorov na natsional'noj stantsii po ispytaniyam reaktorov; Papel de los Metodos No Destructivos en la Explotacion de los Reactores de la National Reactor Testing Station

    Energy Technology Data Exchange (ETDEWEB)

    Francis, W. C.; Brown, E. S.; Burdick, E. E.; Gibson, G. W.; Tingey, F. H. [Phillips Petroleum Company, Atomic Energy Division, Idaho Falls, Idaho (United States)

    1965-10-15

    surface cracks, thermal anneal tests for blistering, and gamma-scanning of irradiated plates. Hydraulic testing of statistical sampling of fuel elements is used to confirm structural integrity, particularly the fuel plate-side plate-joint strength. A continuous effort is made to improve existing techniques and to develop new non-destructive inspection procedures. (author) [French] Les investissements tres importants (plus de 100 millions de dollars) consacres aux reacteurs d'essai du Centre national d'essais de reacteurs et la necessite d'exploiter ces reacteurs en toute securite exigent un controle extremement strict de la qualite des reacteurs et de leurs parties constitutives, notamment des elements combustibles et du dispositif de commande. Les essais non destructifs ont donc joue un role essentiel dans le controle de la qualite de ces pieces avant leur utilisation dans les. reacteurs d'essai. Bien qu'un grand nombre de ces essais non destructifs soient executes selon des procedures bien etablies, on a mis au point de nombreuses methodes inedites et introduit de nouvelles utilisations du materiel classique. On applique depuis longtemps au Centre d'essais les methodes ultrasonores pour la detection des cavites, des defauts de liaison et des craquelures internes. Recemment, on a etendu ces methodes a l'exploration automatique des plaques courbes et a l'inspection des elements combustibles irradies dans les canaux de stockage. Des travaux tres interessants ont permis d'appliquer la methode des ultrasons a la detection des fractures qui peuvent se produire dans l'ame lors du faconnement. Une methode d'exploration par rayons gamma, pour determiner la teneur d'elements combustibles en {sup 23}5{sup U}, s'est revelee tellement fiable qu'elle a ete adoptee pour calculer les penalisations financieres pour les articles non conformes aux specifications. Les radiographies de plaques de combustible donnent les dimensions de l'ame et, associees aux explorations'a l'aide d

  5. Combustion Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — For more than 30 years The Combustion Research Facility (CRF) has served as a national and international leader in combustion science and technology. The need for a...

  6. Alcohol combustion chemistry

    KAUST Repository

    Sarathy, Mani; Oß wald, Patrick; Hansen, Nils; Kohse-Hö inghaus, Katharina

    2014-01-01

    . While biofuel production and its use (especially ethanol and biodiesel) in internal combustion engines have been the focus of several recent reviews, a dedicated overview and summary of research on alcohol combustion chemistry is still lacking. Besides

  7. Maximal combustion temperature estimation

    International Nuclear Information System (INIS)

    Golodova, E; Shchepakina, E

    2006-01-01

    This work is concerned with the phenomenon of delayed loss of stability and the estimation of the maximal temperature of safe combustion. Using the qualitative theory of singular perturbations and canard techniques we determine the maximal temperature on the trajectories located in the transition region between the slow combustion regime and the explosive one. This approach is used to estimate the maximal temperature of safe combustion in multi-phase combustion models

  8. Les impacts des énergies fossiles sur l'environnement

    OpenAIRE

    Landrieu , Guy

    1994-01-01

    La satisfaction de leurs besoins en énergie est l'un des principaux facteurs de la transformation de leur environnement par les sociétés industrielles. Les combustibles carbonés fossiles, qui représentent environ 90% de la production commerciale d'énergie dans le monde, ont un rôle important dans ce processus de transformation. Une première donnée qui explique l'ampleur des impacts sur l'environnement liés aux combustibles fossiles est l'importance des flux de matières en circulation. On extr...

  9. ANALYSE DES PERCEPTIONS LOCALES ET DES FACTEURS ...

    African Journals Online (AJOL)

    AISA

    1Faculté des Sciences Agronomiques (FSA), Université d'Abomey-Calavi (UAC), 01 BP 526 Cotonou Bénin. Email : cgbemavo@yahoo.fr. 2Institut National des Recherches Agricoles du Bénin, Centre de Recherches Agricoles d'Agonkanmey (CRA-A),. Laboratoire des Sciences du Sol, Eau et Environnement (LSSEE).

  10. Vecteurs Singuliers des Theories des Champs Conformes Minimales

    Science.gov (United States)

    Benoit, Louis

    En 1984 Belavin, Polyakov et Zamolodchikov revolutionnent la theorie des champs en explicitant une nouvelle gamme de theories, les theories quantiques des champs bidimensionnelles invariantes sous les transformations conformes. L'algebre des transformations conformes de l'espace-temps presente une caracteristique remarquable: en deux dimensions elle possede un nombre infini de generateurs. Cette propriete impose de telles conditions aux fonctions de correlations qu'il est possible de les evaluer sans aucune approximation. Les champs des theories conformes appartiennent a des representations de plus haut poids de l'algebre de Virasoro, une extension centrale de l'algebre conforme du plan. Ces representations sont etiquetees par h, le poids conforme de leur vecteur de plus haut poids, et par la charge centrale c, le facteur de l'extension centrale, commune a toutes les representations d'une meme theorie. Les theories conformes minimales sont constituees d'un nombre fini de representations. Parmi celles-ci se trouvent des theories unitaires dont les representation forment la serie discrete de l'algebre de Virasoro; leur poids h a la forme h_{p,q}(m)=[ (p(m+1) -qm)^2-1] (4m(m+1)), ou p,q et m sont des entiers positifs et p+q= 2. Ces representations possedent un sous-espace invariant engendre par deux sous-representations avec h_1=h_{p,q} + pq et h_2=h_{p,q} + (m-p)(m+1-q) dont chacun des vecteurs de plus haut poids portent le nom de vecteur singulier et sont notes respectivement |Psi _{p,q}> et |Psi_{m-p,m+1-q}>. . Les theories super-conformes sont une version super-symetrique des theories conformes. Leurs champs appartiennent a des representation de plus haut poids de l'algebre de Neveu-Schwarz, une des deux extensions super -symetriques de l'algebre de Virasoro. Les theories super -conformes minimales possedent la meme structure que les theories conformes minimales. Les representations sont elements de la serie h_{p,q}= [ (p(m+2)-qm)^2-4] /(8m(m+2)) ou p,q et m sont

  11. Solvent purification using a current of water vapour. A continuous process applicable to chemical plants treating irradiated fuels; Purification des solvants par entrainement a la vapeur d'eau. Procede continu applicable aux usines chimiques de traitement des combustibles irradies

    Energy Technology Data Exchange (ETDEWEB)

    Auchapt, P.R.; Sautray, R.R.; Girard, B.R. [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

    1964-07-01

    The pilot plant described in this report is intended for the continuous purification of the solvent used in the plutonium extraction plant at Marcoule, by separating the impurities (fission products). This physical separation is operated by carrying over in a water vapour stream. The contaminating products, only slightly volatile, remain in the form of the droplets and are separated; the vaporised solvent and the water vapour used are condensed and then separated. The originality of the installation resides in the system for pulverising the liquid and in the operating conditions: low working pressure and temperature. The systematic analysis of the various parameters (percentage of residue; flow, pressure and temperature ratios etc...) has shown their influence on the decontamination. The activity due to the zirconium-niobium is undetectable after treatment, and it is easy to obtain decontamination factors of 300 for the ruthenium. The, presence of uranium is favorable for the decontamination. As a conclusion, some extra-technical considerations are given concerning in particular the approximate cost price of the treated solvent per litre. (authors) [French] L'installation pilote decrite dans ce rapport est destinee a purifier, en continu, le solvant utilise a l'usine d'extraction du plutonium de Marcoule, en separant les impuretes (produits de fission). Cette separation physique est realisee par entrainement a la vapeur d'eau. Les produits contaminants, peu volatils, restant sous forme de gouttelettes, sont separes; le solvant vaporise ainsi que la vapeur d'entrainement sont condenses puis separes. L'originalite de l'installation reside dans le systeme de pulverisation du liquide et dans les conditions operatoires: faible pression et basse temperature de fonctionnement. L'analyse systematique des differents parametres (pourcentage de residus, rapport de debits, pression et temperature, etc...) a mis en evidence leur influence

  12. Some economic aspects of natural uranium graphite gas reactor types. Present status and trends of costs in France; Quelques aspects economiques de la filiere uranium naturel - Graphite - gaz. Etat actuel et tendance des couts en France

    Energy Technology Data Exchange (ETDEWEB)

    Gaussens, J; Tanguy, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Leo, B [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    reduction in investment costs can be obtained without relying on fuel enrichment, and that this development is accompanied moreover by improvements in the operational safety of the reactor. The economic aspects of the main technical problems entailed by these developments are discussed: loading and unloading machines, blowers etc... (authors) [French] Dans une premiere partie, on situe l'interet economique de l'utilisation de l'uranium naturel comme combustible. Cet interet reside a la fois dans le nombre limite et la simplicite relative des operations de mise en forme des elements combustibles, dans le faible cout du produit fini par kwh et dans les immobilisations modestes en capital qu'implique ce cycle par rapport ou cycle de l'uranium enrichi. Tous ces elements permettent de reduire le caractere aleatoire des evaluations des couts, particulierement marque dans le cas de l'uranium enrichi, en raison de la complexite de son cycle et des incertitudes concernant le prix du plutonium. Enfin, la diversite des sources d'approvisionnement en concentre d'uranium naturel opposee au quasi monopole actuel de la separation isotopique, et le faible cout du stockage de ce concentre, offrent des garanties en matiere de securite d'approvisionnement et d'independance economique et politique appreciables par rapport a l'uranium enrichi. En ce qui concerne l'ensemble des capitaux immobilises, on montre que si le cout des centrales au graphite-gaz est plus eleve que celui des centrales eau legere pour certaines gammes de puissance, ce resultat est fortement nuance des que l'on fait intervenir dans un souci d'independance nationale le cout de l'equipement de production des combustibles de l'une et l'autre filiere. Enfin, le cout marginal de la puissance du reacteur au graphite est faible, ses limitations technologiques ont considerablement recule (grace en particulier a l'utilisation du beton precontraint). On sait que la tendance actuelle est a l'accroissement de la puissance unitaire des

  13. Device for controlling the current by an electromagnetic load, particularly by an electromagnetic injection valve of an internal combustion engine. Einrichtung zum Steuern des Stromes durch einen elektromagnetischen Verbraucher, insbesondere durch ein elektromagnetisch betaetigbares Einspritzventil einer Brennkraftmaschine

    Energy Technology Data Exchange (ETDEWEB)

    Dilger, P; Hoenig, G; Kauff, H

    1980-07-24

    The invention refers to a device for controlling the current by an electromagnetic load, particularly the electromagnetically actuated injection valve of an internal combustion engine. A first electrical switching device and an ammeter are connected in series with the electromagnetic load between two voltage supply wires, with a free running circuit and a threshold switch together with the ammeter. The invention is characterised by the fact that the free running circuit has a series circuit consisting of a second electrical switching device and a second ammeter, and the first switching device is controlled, depending on time and depending on reaching the upper and lower limits of current flowing through the load and reaching the lower threshold value. The ammeter in the free running circuit has at least one threshold value switch, whose output is coupled to a time control circuit for one of the two switching devices. The time dependent flow control is carried out during the stopping phase of the electro-magnetic load by counting processes.

  14. Uncertainties in hydrogen combustion

    International Nuclear Information System (INIS)

    Stamps, D.W.; Wong, C.C.; Nelson, L.S.

    1988-01-01

    Three important areas of hydrogen combustion with uncertainties are identified: high-temperature combustion, flame acceleration and deflagration-to-detonation transition, and aerosol resuspension during hydrogen combustion. The uncertainties associated with high-temperature combustion may affect at least three different accident scenarios: the in-cavity oxidation of combustible gases produced by core-concrete interactions, the direct containment heating hydrogen problem, and the possibility of local detonations. How these uncertainties may affect the sequence of various accident scenarios is discussed and recommendations are made to reduce these uncertainties. 40 references

  15. Behaviour at the indicator scale of the elements Zr, Hf and 104, Nb,Ta and Pa (105) in very complexation media; Comportement a l`echelle des indicateurs des elements Zr, Hf, et 104, Nb, Ta, et Pa (105) en milieux tres complexants

    Energy Technology Data Exchange (ETDEWEB)

    Monroy Guzman, F. [Institut de Physique Nucleaire, CNRS - IN2P3 Universite Paris Sud, 91406 Orsay Cedex (France)

    1997-12-31

    In order to determine the chemical properties of the trans-actinide elements of Z = 104 and 105 in aqueous solutions we studied their behaviour to ion exchange resin in different complex media. Due to the very short lifetimes (some tens of seconds) et to the low yield of these elements (a few atoms per irradiation hour) only very fast radiochemical techniques can be used. These severe constraints impose comparative studies of these elements with their most likely homologues to be carried out. The corresponding homologues were the elements of group 4 (Zr and Hf) for the element 104 and the elements of group 5 (Nb and Ta) and also Pa for the element 105. The complexation properties of the elements at indicator scale were determined in the media of HF, NH{sub 4}/HClO{sub 4}, NH{sub 4}SCN/HClO{sub 4}, NH{sub 4}SCN/HF and HCl/HF by ion exchange chromatography. The studies in fluorides media allowed us to identify the complexes in solution and to explain the shape of the experimentally observed sorption curves. The decrease of sorption for higher acid concentration in case of HF/HCl medium was interpreted by formation of chloro-fluoro-complexes. In case of the mixture NH{sub 4}SCN/HF, the particularly pronounced anti-synergic effects were observed and discussed. At the same time studies of the Hf and Ta short-lived isotopes were carried out by means of the RACHEL facility operating by the Orsay Tandem accelerator. These realistic simulations allowed optimization of different production, transportation and separation stages of the trans-actinide elements. The two experiments of 104 element production showed that this element forms in HF very stable anionic complexes similarly to its homologues Zr and Hf. (authors). 181 refs.

  16. Behaviour at the indicator scale of the elements Zr, Hf and 104, Nb,Ta and Pa (105) in very complexation media; Comportement a l`echelle des indicateurs des elements Zr, Hf, et 104, Nb, Ta, et Pa (105) en milieux tres complexants

    Energy Technology Data Exchange (ETDEWEB)

    Monroy Guzman, F [Institut de Physique Nucleaire, CNRS - IN2P3 Universite Paris Sud, 91406 Orsay Cedex (France)

    1998-12-31

    In order to determine the chemical properties of the trans-actinide elements of Z = 104 and 105 in aqueous solutions we studied their behaviour to ion exchange resin in different complex media. Due to the very short lifetimes (some tens of seconds) et to the low yield of these elements (a few atoms per irradiation hour) only very fast radiochemical techniques can be used. These severe constraints impose comparative studies of these elements with their most likely homologues to be carried out. The corresponding homologues were the elements of group 4 (Zr and Hf) for the element 104 and the elements of group 5 (Nb and Ta) and also Pa for the element 105. The complexation properties of the elements at indicator scale were determined in the media of HF, NH{sub 4}/HClO{sub 4}, NH{sub 4}SCN/HClO{sub 4}, NH{sub 4}SCN/HF and HCl/HF by ion exchange chromatography. The studies in fluorides media allowed us to identify the complexes in solution and to explain the shape of the experimentally observed sorption curves. The decrease of sorption for higher acid concentration in case of HF/HCl medium was interpreted by formation of chloro-fluoro-complexes. In case of the mixture NH{sub 4}SCN/HF, the particularly pronounced anti-synergic effects were observed and discussed. At the same time studies of the Hf and Ta short-lived isotopes were carried out by means of the RACHEL facility operating by the Orsay Tandem accelerator. These realistic simulations allowed optimization of different production, transportation and separation stages of the trans-actinide elements. The two experiments of 104 element production showed that this element forms in HF very stable anionic complexes similarly to its homologues Zr and Hf. (authors). 181 refs.

  17. Explicit dynamics for numerical simulation of crack propagation by the extended finite element method; Dynamique explicite pour la simulation numerique de propagation de fissure par la methode des elements finis etendus

    Energy Technology Data Exchange (ETDEWEB)

    Menouillard, T

    2007-09-15

    Computerized simulation is nowadays an integrating part of design and validation processes of mechanical structures. Simulation tools are more and more performing allowing a very acute description of the phenomena. Moreover, these tools are not limited to linear mechanics but are developed to describe more difficult behaviours as for instance structures damage which interests the safety domain. A dynamic or static load can thus lead to a damage, a crack and then a rupture of the structure. The fast dynamics allows to simulate 'fast' phenomena such as explosions, shocks and impacts on structure. The application domain is various. It concerns for instance the study of the lifetime and the accidents scenario of the nuclear reactor vessel. It is then very interesting, for fast dynamics codes, to be able to anticipate in a robust and stable way such phenomena: the assessment of damage in the structure and the simulation of crack propagation form an essential stake. The extended finite element method has the advantage to break away from mesh generation and from fields projection during the crack propagation. Effectively, crack is described kinematically by an appropriate strategy of enrichment of supplementary freedom degrees. Difficulties connecting the spatial discretization of this method with the temporal discretization of an explicit calculation scheme has then been revealed; these difficulties are the diagonal writing of the mass matrix and the associated stability time step. Here are presented two methods of mass matrix diagonalization based on the kinetic energy conservation, and studies of critical time steps for various enriched finite elements. The interest revealed here is that the time step is not more penalizing than those of the standard finite elements problem. Comparisons with numerical simulations on another code allow to validate the theoretical works. A crack propagation test in mixed mode has been exploited in order to verify the simulation

  18. Dust Combustion Safety Issues for Fusion Applications

    Energy Technology Data Exchange (ETDEWEB)

    L. C. Cadwallader

    2003-05-01

    This report summarizes the results of a safety research task to identify the safety issues and phenomenology of metallic dust fires and explosions that are postulated for fusion experiments. There are a variety of metal dusts that are created by plasma erosion and disruptions within the plasma chamber, as well as normal industrial dusts generated in the more conventional equipment in the balance of plant. For fusion, in-vessel dusts are generally mixtures of several elements; that is, the constituent elements in alloys and the variety of elements used for in-vessel materials. For example, in-vessel dust could be composed of beryllium from a first wall coating, tungsten from a divertor plate, copper from a plasma heating antenna or diagnostic, and perhaps some iron and chromium from the steel vessel wall or titanium and vanadium from the vessel wall. Each of these elements has its own unique combustion characteristics, and mixtures of elements must be evaluated for the mixture’s combustion properties. Issues of particle size, dust temperature, and presence of other combustible materials (i.e., deuterium and tritium) also affect combustion in air. Combustion in other gases has also been investigated to determine if there are safety concerns with “inert” atmospheres, such as nitrogen. Several coolants have also been reviewed to determine if coolant breach into the plasma chamber would enhance the combustion threat; for example, in-vessel steam from a water coolant breach will react with metal dust. The results of this review are presented here.

  19. Turbulent combustion modelization via a tabulation method of detailed kinetic chemistry coupled to Probability Density Function. Application to aeronautical engines; Modelisation de la combustion turbulente via une methode tabulation de la cinetique chimique detaillee couplee a des fonctions densites de probabilite. Application aux foyers aeronautiques

    Energy Technology Data Exchange (ETDEWEB)

    Rullaud, M

    2004-06-01

    A new modelization of turbulent combustion is proposed with detailed chemistry and probability density functions (PDFs). The objective is to capture temperature and species concentrations, mainly the CO. The PCM-FTC model, Presumed Conditional Moment - Flame Tabulated Chemistry, is based on the tabulation of laminar premixed and diffusion flames to capture partial pre-mixing present in aeronautical engines. The presumed PDFs is introduced to predict averaged values. The tabulation method is based on the analysis of the chemical structure of laminar premixed and diffusion flames. Hypothesis are presented, tested and validated with Sandia experimental data jet flames. Then, the model is introduced in a turbulent flow simulation software. Three configurations are retained to quantify the level of prediction of this formulation: the D and F-Flames of Sandia and lifted jet flames of methane/air of Stanford. A good agreement is observed between experiments and simulations. The validity of this method is then demonstrated. (author)

  20. Scale Effects on Solid Rocket Combustion Instability Behaviour

    OpenAIRE

    David R. Greatrix

    2011-01-01

    The ability to understand and predict the expected internal behaviour of a given solid-propellant rocket motor under transient conditions is important. Research towards predicting and quantifying undesirable transient axial combustion instability symptoms necessitates a comprehensive numerical model for internal ballistic simulation under dynamic flow and combustion conditions. A numerical model incorporating pertinent elements, such as a representative transient, frequency-dependent combusti...

  1. Combustion modeling in internal combustion engines

    Science.gov (United States)

    Zeleznik, F. J.

    1976-01-01

    The fundamental assumptions of the Blizard and Keck combustion model for internal combustion engines are examined and a generalization of that model is derived. The most significant feature of the model is that it permits the occurrence of unburned hydrocarbons in the thermodynamic-kinetic modeling of exhaust gases. The general formulas are evaluated in two specific cases that are likely to be significant in the applications of the model.

  2. Safety report concerning the reactor Pegase - volume 1 - Description of the installation - volume 2 - Safety of the installations; Rapport de surete du reacteur pegase - tome 1 - Description des installations - tome 2 - Surete des installations

    Energy Technology Data Exchange (ETDEWEB)

    Lacour, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Legoin, P. [S.E.M. Hispano-Suiza, 92 - Colombes (France)

    1964-07-01

    In the first volume: This report is a description of the reactor Pegase, given with a view to examine the safety of the installations. The Cadarache site at which they are situated is briefly described, in particular because of the consequences on the techniques employed for building Pegase. A description is also given of the original aspects of the reactor. The independent loops which are designed for full-scale testing of fuel elements used in natural uranium-gas-graphite reactor systems are described in this report, together with their operational and control equipment. In the second volume: In the present report are examined the accidents which could cause damage to the Pegase reactor installation. Among possible causes of accidents considered are the seismicity of the region, an excessive power excursion of the reactor and a fracture in the sealing of an independent loop. Although all possible precautions have been taken to offset the effects of such accidents, their ultimate consequences are considered here. The importance is stressed of the security action and regulations which, added to the precautions taken for the construction, ensure the safety of the installations. (authors) [French] Dans le volume 1: Ce rapport est une description du reacteur Pegase, afin d'examiner la surete des installations. Le site de CADARACHE ou elles sont situees, a ete sommairement decrit, en particulier, a cause des consequences sur les techniques mises en oeuvre pour la realisation de Pegase. Nous nous sommes egalement attache a decrire les aspects originaux du reacteur. Les boucles autonomes destinees a tester en vraie grandeur des elements combustibles de la filiere uranium naturel graphite-gaz, ainsi que leurs dispositifs de controle et d'exploitation, figurent egalement dans ce rapport. Dans le volume 2: Dans le present rapport, nous examinons des accidents pouvant endommager des installations du reacteur Pegase. Les origines d'accidents examines

  3. Safety report concerning the reactor Pegase - volume 1 - Description of the installation - volume 2 - Safety of the installations; Rapport de surete du reacteur pegase - tome 1 - Description des installations - tome 2 - Surete des installations

    Energy Technology Data Exchange (ETDEWEB)

    Lacour, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Legoin, P [S.E.M. Hispano-Suiza, 92 - Colombes (France)

    1964-07-01

    In the first volume: This report is a description of the reactor Pegase, given with a view to examine the safety of the installations. The Cadarache site at which they are situated is briefly described, in particular because of the consequences on the techniques employed for building Pegase. A description is also given of the original aspects of the reactor. The independent loops which are designed for full-scale testing of fuel elements used in natural uranium-gas-graphite reactor systems are described in this report, together with their operational and control equipment. In the second volume: In the present report are examined the accidents which could cause damage to the Pegase reactor installation. Among possible causes of accidents considered are the seismicity of the region, an excessive power excursion of the reactor and a fracture in the sealing of an independent loop. Although all possible precautions have been taken to offset the effects of such accidents, their ultimate consequences are considered here. The importance is stressed of the security action and regulations which, added to the precautions taken for the construction, ensure the safety of the installations. (authors) [French] Dans le volume 1: Ce rapport est une description du reacteur Pegase, afin d'examiner la surete des installations. Le site de CADARACHE ou elles sont situees, a ete sommairement decrit, en particulier, a cause des consequences sur les techniques mises en oeuvre pour la realisation de Pegase. Nous nous sommes egalement attache a decrire les aspects originaux du reacteur. Les boucles autonomes destinees a tester en vraie grandeur des elements combustibles de la filiere uranium naturel graphite-gaz, ainsi que leurs dispositifs de controle et d'exploitation, figurent egalement dans ce rapport. Dans le volume 2: Dans le present rapport, nous examinons des accidents pouvant endommager des installations du reacteur Pegase. Les origines d'accidents examines comprennent la seismicite

  4. Determination of primary combustion source organic carbon-to-elemental carbon (OC / EC ratio using ambient OC and EC measurements: secondary OC-EC correlation minimization method

    Directory of Open Access Journals (Sweden)

    C. Wu

    2016-05-01

    Full Text Available Elemental carbon (EC has been widely used as a tracer to track the portion of co-emitted primary organic carbon (OC and, by extension, to estimate secondary OC (SOC from ambient observations of EC and OC. Key to this EC tracer method is to determine an appropriate OC / EC ratio that represents primary combustion emission sources (i.e., (OC / ECpri at the observation site. The conventional approaches include regressing OC against EC within a fixed percentile of the lowest (OC / EC ratio data (usually 5–20 % or relying on a subset of sampling days with low photochemical activity and dominated by local emissions. The drawback of these approaches is rooted in its empirical nature, i.e., a lack of clear quantitative criteria in the selection of data subsets for the (OC / ECpri determination. We examine here a method that derives (OC / ECpri through calculating a hypothetical set of (OC / ECpri and SOC followed by seeking the minimum of the coefficient of correlation (R2 between SOC and EC. The hypothetical (OC / ECpri that generates the minimum R2(SOC,EC then represents the actual (OC / ECpri ratio if variations of EC and SOC are independent and (OC / ECpri is relatively constant in the study period. This Minimum R Squared (MRS method has a clear quantitative criterion for the (OC / ECpri calculation. This work uses numerically simulated data to evaluate the accuracy of SOC estimation by the MRS method and to compare with two commonly used methods: minimum OC / EC (OC / ECmin and OC / EC percentile (OC / EC10 %. Log-normally distributed EC and OC concentrations with known proportion of SOC are numerically produced through a pseudorandom number generator. Three scenarios are considered, including a single primary source, two independent primary sources, and two correlated primary sources. The MRS method consistently yields the most accurate SOC estimation. Unbiased SOC estimation by OC

  5. Modelisation des effets physico-techniques pour la conception des ...

    African Journals Online (AJOL)

    automatisation dans les installations industrielles a besoin d'une régulation automatique des commandes des processus technologiques pour lesquelles certaines contraintes sont à relever compte tenu des exigences des innovations scientifiques de ...

  6. Lump wood combustion process

    Science.gov (United States)

    Kubesa, Petr; Horák, Jiří; Branc, Michal; Krpec, Kamil; Hopan, František; Koloničný, Jan; Ochodek, Tadeáš; Drastichová, Vendula; Martiník, Lubomír; Malcho, Milan

    2014-08-01

    The article deals with the combustion process for lump wood in low-power fireplaces (units to dozens of kW). Such a combustion process is cyclical in its nature, and what combustion facility users are most interested in is the frequency, at which fuel needs to be stoked to the fireplace. The paper defines the basic terms such as burnout curve and burning rate curve, which are closely related to the stocking frequency. The fuel burning rate is directly dependent on the immediate thermal power of the fireplace. This is also related to the temperature achieved in the fireplace, magnitude of flue gas losses and the ability to generate conditions favouring the full burnout of the fuel's combustible component, which, at once ensures the minimum production of combustible pollutants. Another part of the paper describes experiments conducted in traditional fireplaces with a grate, at which well-dried lump wood was combusted.

  7. The Use of Research Reactors and Short-Lived Isotopes in the Study of Nuclear-Reactor Fuel Materials; Emploi de Reacteurs de Recherche et de Radioisotopes de Courte Periode dans l'Etude des Combustibles pour Reacteurs Nucleaires; ИСПОЛЬЗОВАНИЕ ИССЛЕДОВАТЕЛЬСКИХ РЕАКТОРОВ И КОРОТКОЖИВУЩИХ ИЗОТОПОВ ПРИ ИЗУЧЕНИИ ТОПЛИВНЫХ МАТЕРИАЛОВ ДЛЯ ЯДЕРННХ РЕАКТОРОВ; Empleo de Reactores de Investigacion y de Isotopos de Periodo Corto en el Estudio de Combustibles Nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Elleman, T. S.; Townley, C. W.; Sunderman, D. N. [Battelle Memorial Institute, Columbus, OH (United States)

    1963-03-15

    can often exhibit preferential release of particular elements, rapid fission- product release during temperature changes, and fission-gas release after reactor shutdown. The use of this technique allows fundamental information to be obtained on the performance of prototype fuel materials without the necessity for large testing reactors or high-level cave facilities for handling irradiated specimens. (author) [French] On peut employer avec profit un reacteur de recherche pour etudier la mobilite des produits de fission dans les prototypes de combustibles nucleaires en creant un milieu analogue a celui dans lequel le combustible est appele a fonctionner normalement, et en controlant rigoureusement les conditions de l'experience, tout en prevoyant une certaine souplesse dans le dispositif d'experimentation. Si l'on fait varier les conditions d'irradiation et que l'on procede a une analyse quantitative des produits de fission de courte periode liberes par l'echantillon, on pourra determiner les mecanismes de la liberation des produits de fission et leurs rapports avec les proprietes physiques et chimiques tant du combustible servant d'echantillon que des produits de fission eux-memes. On pourra en outre obtenir des donnees de technogenie utiles sur la valeur brute de la radioactivite liberee et la duree de vie probable du combustible. En regle generale, on irradie les echantillons dans des capsules a double paroi qu'on chauffe et introduit dans la piscine ou dans les canaux d'irradiation du reacteur, les produits de fission volatils liberes etant elimines de la capsule par un gaz de balayage. Etant donne .que le rapport entre la vitesse de degagement et la periode du radioisotope constitue un indice important du mecanisme, on recueille et analyse les gaz de fission- krypton et xenon - dont la periode va de 1,7 s jusqu'a 5,3 d. On determine les gaz rares de courte periode (krypton-89, krypton-91, krypton-92, xenon-137, xenon-138, xenon-139, xenon-140 et xenon-141) en

  8. Concentrations of inorganic elements in biomass fuels and recovery in the different ash fractions

    NARCIS (Netherlands)

    Obernberger, I.; Biedermann, F.; Widmann, W.; Riedl, R.

    1997-01-01

    Inorganic elements and compounds in biomass fuels influence the combustion process and the composition of the ashes produced. Consequently, knowledge about the material fluxes of inorganic elements and compounds during biomass combustion for different kinds of biofuels and their influencing

  9. Quality Determination of Biomass for Combustion

    DEFF Research Database (Denmark)

    Liu, Na; Jørgensen, Uffe; Lærke, Poul Erik

    2013-01-01

    A high content of minerals in biomass feedstock may cause fouling, slagging, and corrosion in the furnace during combustion. Here, a new pressurized microwave digestion method for biomass digestion prior to elemental analysis is presented. This high-throughput method is capable of processing...

  10. Flameless Combustion Workshop

    National Research Council Canada - National Science Library

    Gutmark, Ephraim

    2005-01-01

    .... "Flameless Combustion" is characterized by high stability levels with virtually no thermoacoustic instabilities, very low lean stability limits and therefore extremely low NOx production, efficient...

  11. Research Combustion Laboratory (RCL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Research Combustion Laboratory (RCL) develops aerospace propulsion technology by performing tests on propulsion components and materials. Altitudes up to 137,000...

  12. Combustion Byproducts Recycling Consortium

    Energy Technology Data Exchange (ETDEWEB)

    Paul Ziemkiewicz; Tamara Vandivort; Debra Pflughoeft-Hassett; Y. Paul Chugh; James Hower

    2008-08-31

    Ashlines: To promote and support the commercially viable and environmentally sound recycling of coal combustion byproducts for productive uses through scientific research, development, and field testing.

  13. variabilite des productions et des revenus des exploitations

    African Journals Online (AJOL)

    3Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), UMR Innovation,. Montpellier, France. Doubangolo COULIBALY, Email kone_b@yahoo.fr. RESUME. La durabilité des systèmes de production à base de coton dans un contexte de variabilité des prix aux producteurs et de ...

  14. Theoretical and experimental investigations of on-board control of combustion air and/or fuel for emission reduction in internal combustion engines. Final report; Durchfuehrung theoretischer und experimenteller Untersuchungen zu den Moeglichkeiten der On-Board-Beeinflussung der Verbrennungsluftzusammensetzung und/oder des Kraftstoffs fuer Verbrennungsmotoren mit dem Ziel der Emissionsminderung. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Velji, A.; Hofmann, U.

    2001-11-01

    Theoretical and experimental investigations were made in order to find the optimal composition of combustion air for simultaneous reduction of NOx and particulate emissions. The effect was found to be in the same order of magnitude as with exhaust recirculation. 'Optimized' air should have an oxygen content of more than 20 percent and a CO2 content of more than 10 percent, with nitrogen more or less accounting for the rest. [German] Ausgehend von der Abgasrueckfuehrung wurde in theoretischen und experimentellen Untersuchungen die optimale Zusammensetzung der Verbrennungsluft zur gleichzeitigen Reduktion der NO{sub x}- und Partikelemission ermittelt. Es konnte gezeigt werden, dass es mit dieser Verbrennungsluft moeglich ist, eine aehnlich hohe NO{sub x}-Reduktion wie bei der Abgasrueckfuehrung zu erzielen, ohne dass die Partikelemission drastisch ansteigt. Die 'optimale' Verbrennungsluft muss einen Sauerstoffgehalt groesser als 20% und einen CO{sub 2}-Gehalt groesser als 10% aufweisen. Der Rest besteht im Wesentlichen aus Stickstoff. (orig.)

  15. Combustion instability modeling and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States)] [and others

    1995-10-01

    It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. Clearly, the key to successful gas turbine development is based on understanding the effects of geometry and operating conditions on combustion instability, emissions (including UHC, CO and NO{sub x}) and performance. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors.

  16. Combustion Stratification for Naphtha from CI Combustion to PPC

    KAUST Repository

    Vallinayagam, R.; Vedharaj, S.; An, Yanzhao; Dawood, Alaaeldin; Izadi Najafabadi, Mohammad; Somers, Bart; Johansson, Bengt

    2017-01-01

    This study demonstrates the combustion stratification from conventional compression ignition (CI) combustion to partially premixed combustion (PPC). Experiments are performed in an optical CI engine at a speed of 1200 rpm for diesel and naphtha (RON

  17. Unburned carbon in combustion residues from mainly solid biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Bjurstroem H; Lind B; Lagerkvist A

    2012-02-15

    Unburned carbon in 21 combustion residues from solid biofuels is investigated using several methods of analysis (a.o. LOI and TOC), as well as micro-Raman spectroscopy. The results are used to discuss the distribution of unburned carbon in the residues from the different combustion plants and its nature (organic or elemental). The consequences of the elemental nature of carbon for environmental properties of the residue are noted

  18. Determining a pool - type reactor fuel policy; Recherche d'une politique de gestion du combustible d'une pile piscine

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1964-07-01

    Refuelling the 10 to 15 MW pool type reactor considered here will occur frequently (some 10 elements every 3 to 4 weeks). It is therefore necessary to determine the most economic fuel policy. This study proposes to define a strategy that will make it possible to decide on the number and characteristics of the shipment containers, as well as on the means of storage, so as to reduce the risks as much as possible should the basic parameters of the study vary. Among these parameters, the respective influence of which is investigated, chemical reprocessing costs play a vital part. Two examples of optimum fuel management are given according to whether the reprocessing charges applied are those of the old or of the 1961 U.S. AEC base charges for reprocessing highly enriched irradiated fuel. (authors) [French] Les renouvellements du combustible de la pile piscine de 10 a 15 MW consideree ici, seront frequents (quelques 10 elements toutes les 3 ou 4 semaines). Il est donc important de connaitre les meilleures conditions de gestion economique de ce combustible. Cette etude se propose de definir une strategie permettant de choisir le nombre et les caracteristiques des containers de transport, ainsi que les moyens de stockage, de facon a minimiser les risques si les parametres de base de l'etude varient. Parmi ces parametres dont l'influence respective est successivement examinee, le cout du traitement chimique joue un role fondamental. Deux exemples d'optimum de gestion sont donnes selon que le tarif de retraitement est conforme a l'ancien tarif de l'U.S. AEC ou au tarif 1961 de traitement des combustibles irradies tres enrichis. (auteurs)

  19. Deformation analysis of rotary combustion engine housings

    Science.gov (United States)

    Vilmann, Carl

    1991-01-01

    This analysis of the deformation of rotary combustion engine housings targeted the following objectives: (1) the development and verification of a finite element model of the trochoid housing, (2) the prediction of the stress and deformation fields present within the trochoid housing during operating conditions, and (3) the development of a specialized preprocessor which would shorten the time necessary for mesh generation of a trochoid housing's FEM model from roughly one month to approximately two man hours. Executable finite element models were developed for both the Mazda and the Outboard Marine Corporation trochoid housings. It was also demonstrated that a preprocessor which would hasten the generation of finite element models of a rotary engine was possible to develop. The above objectives are treated in detail in the attached appendices. The first deals with finite element modeling of a Wankel engine center housing, and the second with the development of a preprocessor that generates finite element models of rotary combustion engine center housings. A computer program, designed to generate finite element models of user defined rotary combustion engine center housing geometries, is also included.

  20. Multi-Dimensional Modeling of the Aerodynamic and Combustion in Diesel Engines Modélisation multidimensionnelle de l'aérodynamique et de la combustion dans les moteurs diesel

    Directory of Open Access Journals (Sweden)

    Delhaye B.

    2006-12-01

    Full Text Available The purpose of this paper is to present an overview of Computational Fluid Dynamics (CFD and combustion simulation applications to automotive power train development, and the methodologies we developed at PSA to integrate numerical simulation into the development process. We illustrate these methodologies with some applications concerning the development of PSA HDI engines. Dans cet article, on présente un panorama des applications de la mécanique des fluides numérique et de la simulation de la combustion pour le développement des groupes motopropulseurs, ainsi que les méthodologies que nous avons conçues au sein du groupe PSA pour intégrer la simulation numérique dans ce processus de développement. Nous illustrons cette démarche par des exemples d'applications issues du développement des moteurs HDI injection directe common rail de PSA.

  1. Co-combustion of anthracite coal and wood pellets: Thermodynamic analysis, combustion efficiency, pollutant emissions and ash slagging.

    Science.gov (United States)

    Guo, Feihong; Zhong, Zhaoping

    2018-08-01

    This work presents studies on the co-combustion of anthracite coal and wood pellets in fluidized bed. Prior to the fluidized bed combustion, thermogravimetric analysis are performed to investigate the thermodynamic behavior of coal and wood pellets. The results show that the thermal decomposition of blends is divided into four stages. The co-firing of coal and wood pellets can promote the combustion reaction and reduce the emission of gaseous pollutants, such as SO 2 and NO. It is important to choose the proportion of wood pellets during co-combustion due to the low combustion efficiency caused by large pellets with poor fluidization. Wood pellets can inhibit the volatilization of trace elements, especially for Cr, Ni and V. In addition, the slagging ratio of wood pellets ash is reduced by co-firing with coal. The research on combustion of coal and wood pellets is of great significance in engineering. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Development and validation of an Eulerian model towards the simulation of fuel injection in internal combustion engines; Developpement et validation d'un modele eulerien en vue de la simulation des jets de carburants dans les moteurs a combustion interne

    Energy Technology Data Exchange (ETDEWEB)

    Truchot, B.

    2005-12-15

    The objective of this work is to develop an Eulerian two phase model to improve the prediction of fuel injection in internal combustion engines, particularly the dense liquid zone close to the nozzle. Lagrangian models, usually used in engine simulations, are based on the assumption of dispersed two phase flows with low liquid volume fraction, which is not fulfilled in the case of direct injection engine technology. Different Eulerian approaches are available in the literature. Physical phenomena that occur near the nozzle and characteristics of each model lead to the choice of a two fluids two pressures model. Several open terms appear in the equations of the model: exchange between the two phases and turbulent correlations. Closures of exchange terms are based on the spherical droplets hypothesis while a RANS approach is adopted to close turbulent correlations. This model has been integrated in the IFP CFD code, IFP-C3D. Several numerical tests and analytical validations (for single and two phase flows) have been then carried out in order to check the correct implementation of equations and the predictivity of the model and closures. Modifications in the turbulent model of the gas have required validations in both the gas phase (flow behind a sudden enlargement) and the liquid phase (pure liquid injection). A two phase mixing layer has been then used to validate the whole model. Finally, injection tests have been achieved under realistic conditions (similar to those encountered in automotive engines) in order to check the feasibility of engine computations using the developed Eulerian approach. These tests have also allowed to check the compatibility of this approach with the specificities of engine simulations (especially mesh movement). (author)

  3. Strobes: An oscillatory combustion

    NARCIS (Netherlands)

    Corbel, J.M.L.; Lingen, J.N.J. van; Zevenbergen, J.F.; Gijzeman, O.L.J.; Meijerink, A.

    2012-01-01

    Strobe compositions belong to the class of solid combustions. They are mixtures of powdered ingredients. When ignited, the combustion front evolves in an oscillatory fashion, and flashes of light are produced by intermittence. They have fascinated many scientists since their discovery at the

  4. Catalytically enhanced combustion process

    International Nuclear Information System (INIS)

    Rodriguez, C.

    1992-01-01

    This patent describes a fuel having improved combustion efficiency. It comprises a petroleum based liquid hydrocarbon; and a combustion catalyst comprising from about 18 to about 21 weight percent naphthalene, from about 75 to about 80 weight percent toluene, and from about 2.8 to about 3.2 weight percent benzyl alcohol

  5. Fifteenth combustion research conference

    International Nuclear Information System (INIS)

    1993-01-01

    The BES research efforts cover chemical reaction theory, experimental dynamics and spectroscopy, thermodynamics of combustion intermediates, chemical kinetics, reaction mechanisms, combustion diagnostics, and fluid dynamics and chemically reacting flows. 98 papers and abstracts are included. Separate abstracts were prepared for the papers

  6. Fuels and Combustion

    KAUST Repository

    Johansson, Bengt

    2016-08-17

    This chapter discusses the combustion processes and the link to the fuel properties that are suitable for them. It describes the basic three concepts, including spark ignition (SI) and compression ignition (CI), and homogeneous charge compression ignition (HCCI). The fuel used in a CI engine is vastly different from that in an SI engine. In an SI engine, the fuel should sustain high pressure and temperature without autoignition. Apart from the dominating SI and CI engines, it is also possible to operate with a type of combustion: autoignition. With HCCI, the fuel and air are fully premixed before combustion as in the SI engine, but combustion is started by the increased pressure and temperature during the compression stroke. Apart from the three combustion processes, there are also a few combined or intermediate concepts, such as Spark-Assisted Compression Ignition (SACI). Those concepts are discussed in terms of the requirements of fuel properties.

  7. Fuels and Combustion

    KAUST Repository

    Johansson, Bengt

    2016-01-01

    This chapter discusses the combustion processes and the link to the fuel properties that are suitable for them. It describes the basic three concepts, including spark ignition (SI) and compression ignition (CI), and homogeneous charge compression ignition (HCCI). The fuel used in a CI engine is vastly different from that in an SI engine. In an SI engine, the fuel should sustain high pressure and temperature without autoignition. Apart from the dominating SI and CI engines, it is also possible to operate with a type of combustion: autoignition. With HCCI, the fuel and air are fully premixed before combustion as in the SI engine, but combustion is started by the increased pressure and temperature during the compression stroke. Apart from the three combustion processes, there are also a few combined or intermediate concepts, such as Spark-Assisted Compression Ignition (SACI). Those concepts are discussed in terms of the requirements of fuel properties.

  8. PDF Modeling of Turbulent Combustion

    National Research Council Canada - National Science Library

    Pope, Stephen B

    2006-01-01

    .... The PDF approach to turbulent combustion has the advantages of fully representing the turbulent fluctuations of species and temperature, and of allowing realistic combustion chemistry to be implemented...

  9. Efficient catalytic combustion in integrated micropellistors

    International Nuclear Information System (INIS)

    Bársony, I; Ádám, M; Fürjes, P; Dücső, Cs; Lucklum, R; Hirschfelder, M; Kulinyi, S

    2009-01-01

    This paper analyses two of the key issues of the development of catalytic combustion-type sensors: the selection and production of active catalytic particles on the micropellistor surface as well as the realization of a reliable thermal conduction between heater element and catalytic surface, for the sensing of temperature increase produced by the combustion. The report also demonstrates that chemical sensor product development by a MEMS process is a continuous struggle for elimination of all uncertainties influencing reliability and sensitivity of the final product

  10. Civili, langue des Baloango

    DEFF Research Database (Denmark)

    Mavoungou, Paul Achille; Ndinga-Koumba-Binza, Hugues Steve

    , Congo, Angola, etc.) issus de la décolonisation. Il présente de façon succincte quelques phénomènes historiques, phonologiques, morphosyntaxiques, homonymiques et analogiques de la langue. Des faits sémantiques des emprunts linguistiques y sont également décrits dans le cadre des changements...

  11. Non-Destructive Methods for Determining Burn-Up in Nuclear Fuel; Methodes Non Destructives d'Evaluation du Taux de Combustion dans le Combustible Nucleaire; Metody opredeleniya vygoraniya v yadernom toplive bez razrusheniya obraztsa; Metodos No Destructivos para Determinai el Grado de Combustion de los Elementos Combustibles Nucleares

    Energy Technology Data Exchange (ETDEWEB)

    McGonnagle, W. J. [Illinois Institute of Technology, Chicago, IL (United States)

    1966-02-15

    is of secondary importance and the cooling time is unimportant. Also, there is more precise nuclear data for the stable fission products. Of the stable isotopes produced during the fission process, zirconium, molybdenum, ruthenium, and neodymium appear to be the most useful. The proposed non-destructive methods using stable isotopes will be discussed. (author) [French] Il est a la fois utile et souhaitable d'utiliser des methodes non destructives pour proceder a la mesure quantitative du taux de combustion des elements combustibles d'un reacteur nucleaire. L'ideal serait de pouvoir analyser le combustible a l'aide d'une methode ne necessitant pas de renseignements particuliers sur les spectres des neutrons, le schema d'irradiation ou le temps de refroidissement. Les isotopes radioactifs et les isotopes stables resultant du processus de fission qui sont presents dans un element combustible irradie caracterisent son irradiation. Malheureusement, que l'analyse soit effectuee au moyen de methodes destructives ou non destructives, les resultats obtenus varient en fonction du spectre de neutrons, du schema d'irradiation et du temps de refroidissement. Deplus, l'absence de donnees nucleaires precises, comme les valeurs des section efficaces, influe sur tous les calculs qui peuvent etre effectues. L'analyse non destructive est egalement genee par la presence de champs de rayonnements intenses qui augmentent le bruit de fond. Il est difficile d'etablir des normes utiles et realistes. Bien que, dans l'etat actuel de la technique, les methodes non destructives n'aient pas toute la precision et l'exactitude voulues, elles presentent neanmoins un grand interet' notamment dans les cas ou il faut obtenir rapidement et economiquement une valeur approximative du taux de combustion. Plusieurs methodes non destructives d'evaluation du taux de combustion sont actuellement appliquees, a l'etude ou en projet. Plusieurs types de spectrometres sont utilises pour la mesure du rayonnement

  12. Effets des electrons secondaires sur l'ADN

    Science.gov (United States)

    Boudaiffa, Badia

    Les interactions des electrons de basse energie (EBE) representent un element important en sciences des radiations, particulierement, les sequences se produisant immediatement apres l'interaction de la radiation ionisante avec le milieu biologique. Il est bien connu que lorsque ces radiations deposent leur energie dans la cellule, elles produisent un grand nombre d'electrons secondaires (4 x 104/MeV), qui sont crees le long de la trace avec des energies cinetiques initiales bien inferieures a 20 eV. Cependant, il n'y a jamais eu de mesures directes demontrant l'interaction de ces electrons de tres basse energie avec l'ADN, du principalement aux difficultes experimentales imposees par la complexite du milieu biologique. Dans notre laboratoire, les dernieres annees ont ete consacrees a l'etude des phenomenes fondamentaux induits par impact des EBE sur differentes molecules simples (e.g., N2, CO, O2, H2O, NO, C2H 4, C6H6, C2H12) et quelques molecules complexes dans leur phase solide. D'autres travaux effectues recemment sur des bases de l'ADN et des oligonucleotides ont montre que les EBE produisent des bris moleculaires sur les biomolecules. Ces travaux nous ont permis d'elaborer des techniques pour mettre en evidence et comprendre les interactions fondamentales des EBE avec des molecules d'interet biologique, afin d'atteindre notre objectif majeur d'etudier l'effet direct de ces particules sur la molecule d'ADN. Les techniques de sciences des surfaces developpees et utilisees dans les etudes precitees peuvent etre etendues et combinees avec des methodes classiques de biologie pour etudier les dommages de l'ADN induits par l'impact des EBE. Nos experiences ont montre l'efficacite des electrons de 3--20 eV a induire des coupures simple et double brins dans l'ADN. Pour des energies inferieures a 15 eV, ces coupures sont induites par la localisation temporaire d'un electron sur une unite moleculaire de l'ADN, ce qui engendre la formation d'un ion negatif transitoire

  13. Study of atmospheric emissions from liquid and solid fuels burning facilities and from raw phosphate chemical treatment in Sfax City (Tunisia); Etude des residus de combustion des fuels liquide et solide et de traitement chimique du phosphate brut dans la ville de Sfax (Tunisie)

    Energy Technology Data Exchange (ETDEWEB)

    Azri, Ch; Tili, A.; Serbaji, M.M. [Faculte des Sciences de Sfax, Dept. des Sciences de la Terre, Sfax (Tunisia); Medhioub, K. [Institut Preparatoire aux Etudes d' Ingenieurs de Sfax (IPEIS), Sfax (Tunisia)

    2002-07-01

    Study of atmospheric emissions from solid and liquid fuels burning facilities and from chemical treatment processes of raw phosphate in Sfax City (Tunisia) shows different forms of pollution concerning mainly sulfur oxides (SO{sub x}), sulfuric and phosphoric acid mists, fluorinated compounds and dust. Limited performances of amortized and/or over used de-pollution systems can explain high atmospheric emissions above emission limits. Gaseous pollution has been shown as coming mainly from phosphate treatment processes inside the chemical complex 'SIAPE' while particulate pollution is coming from all specific industries (SIAPE, charcoal facilities and weaving and soap factories). Calculated emission factors of these industries for some heavy metals (Pb, Cd, Ni, Cu, Zn) are very different. They are ranging from 0.3 to 9.5 g/t for phosphate treatment residues. Excepted Ni with 15.5 g/t, they are rather small for heavy fuels combustion residues. It, nevertheless, exceeds the emission factor of Ni for the phosphate treatment process. Volumes of emissions and calculated annual fluxes of metals are showing that 'SIAPE' could be a potential source of atmospheric pollution in the city. Its contribution to metal emissions is really exceeding emissions from well identified heavy fuels burning facilities in the city. Just to compare, Ni emissions from its processes are equal to emissions from 38 heavy fuels burning facilities of 4.8 t/day capacity (Ni 1 046 kg/year instead of 27 kg/year). Such a fact is clearly pointing out the high level of anthropogenic pollution from chemical processes adopted for primary matter transformation. They hence should be fitted with suitable de-pollution systems. (authors)

  14. Fuel Combustion Laboratory | Transportation Research | NREL

    Science.gov (United States)

    Fuel Combustion Laboratory Fuel Combustion Laboratory NREL's Fuel Combustion Laboratory focuses on designs, using both today's technology and future advanced combustion concepts. This lab supports the combustion chamber platform for fuel ignition kinetics research, was acquired to expand the lab's

  15. Combustion of biodiesel in a large-scale laboratory furnace

    International Nuclear Information System (INIS)

    Pereira, Caio; Wang, Gongliang; Costa, Mário

    2014-01-01

    Combustion tests in a large-scale laboratory furnace were carried out to assess the feasibility of using biodiesel as a fuel in industrial furnaces. For comparison purposes, petroleum-based diesel was also used as a fuel. Initially, the performance of the commercial air-assisted atomizer used in the combustion tests was scrutinized under non-reacting conditions. Subsequently, flue gas data, including PM (particulate matter), were obtained for various flame conditions to quantify the effects of the atomization quality and excess air on combustion performance. The combustion data was complemented with in-flame temperature measurements for two representative furnace operating conditions. The results reveal that (i) CO emissions from biodiesel and diesel combustion are rather similar and not affected by the atomization quality; (ii) NO x emissions increase slightly as spray quality improves for both liquid fuels, but NO x emissions from biodiesel combustion are always lower than those from diesel combustion; (iii) CO emissions decrease rapidly for both liquid fuels as the excess air level increases up to an O 2 concentration in the flue gas of 2%, beyond which they remain unchanged; (iv) NO x emissions increase with an increase in the excess air level for both liquid fuels; (v) the quality of the atomization has a significant impact on PM emissions, with the diesel combustion yielding significantly higher PM emissions than biodiesel combustion; and (vi) diesel combustion originates PM with elements such as Cr, Na, Ni and Pb, while biodiesel combustion produces PM with elements such as Ca, Mg and Fe. - Highlights: • CO emissions from biodiesel and diesel tested are similar. • NO x emissions from biodiesel tested are lower than those from diesel tested. • Diesel tested yields significantly higher PM (particulate matter) emissions than biodiesel tested. • Diesel tested originates PM with Cr, Na, Ni and Pb, while biodiesel tested produces PM with Ca, Mg and Fe

  16. Sandia Combustion Research: Technical review

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    This report contains reports from research programs conducted at the Sandia Combustion Research Facility. Research is presented under the following topics: laser based diagnostics; combustion chemistry; reacting flow; combustion in engines and commercial burners; coal combustion; and industrial processing. Individual projects were processed separately for entry onto the DOE databases.

  17. Cycle for fuel elements. Uranium production, programs for nuclear power stations and capital expenditure involved; Cycles de combustibles. Production d'uranium, programme de centrales electriques et effort financier correspondant

    Energy Technology Data Exchange (ETDEWEB)

    Andriot, J; Gaussens, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    A number of different possible programs for nuclear power stations of various types are presented in this survey. These programs are established in relation to the use of uranium and thorium in amounts similar to those that shall probably be produced in France during the next fifteen years. As it is possible to draw plans for nuclear power stations in which several processes exist simultaneously, an unlimited number of variations being thinkable, this survey is limited to successive analysis of the results obtained by use of only one of each of the following three systems: - system natural uranium-graphite, - system natural uranium-heavy water, -system enriched uranium-pressurised light water. All schemes are considered as assemblages of these three simple systems. The effects of plutonium recycling are also considered for each system. The electric power installed and the capacity of stations situated up-stream and down-stream have been calculated by this method and an attempt has been made to establish the sum to be invested during the fifteen years necessary for the launching of the programs scheduled. A table of timing for the investments groups the results obtained. Considering the fact that French availabilities in capital shall not be unlimited during the coming years, this way of presenting the results seems to be interesting. (author)Fren. [French] L'etude presentee comporte l'examen d'un certain nombre d'hypotheses de programmes de centrales nucleaires de types differents. Ces programmes correspondent a l'utilisation de tonnages d'uranium et de thorium de l'ordre de grandeur de ceux qui seront probablement produits par la France dans les quinze prochaines annees. Comme il est possible de batir un programme de centrales nucleaires, comportant a la fois plusieurs filieres suivant des variantes en nombre infini, on s'est contente d'examiner successivement les resultats ous si on utilisait exclusivement l'une des trois filieres suivantes: - filiere uranium

  18. Cycle for fuel elements. Uranium production, programs for nuclear power stations and capital expenditure involved; Cycles de combustibles. Production d'uranium, programme de centrales electriques et effort financier correspondant

    Energy Technology Data Exchange (ETDEWEB)

    Andriot, J.; Gaussens, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    A number of different possible programs for nuclear power stations of various types are presented in this survey. These programs are established in relation to the use of uranium and thorium in amounts similar to those that shall probably be produced in France during the next fifteen years. As it is possible to draw plans for nuclear power stations in which several processes exist simultaneously, an unlimited number of variations being thinkable, this survey is limited to successive analysis of the results obtained by use of only one of each of the following three systems: - system natural uranium-graphite, - system natural uranium-heavy water, -system enriched uranium-pressurised light water. All schemes are considered as assemblages of these three simple systems. The effects of plutonium recycling are also considered for each system. The electric power installed and the capacity of stations situated up-stream and down-stream have been calculated by this method and an attempt has been made to establish the sum to be invested during the fifteen years necessary for the launching of the programs scheduled. A table of timing for the investments groups the results obtained. Considering the fact that French availabilities in capital shall not be unlimited during the coming years, this way of presenting the results seems to be interesting. (author)Fren. [French] L'etude presentee comporte l'examen d'un certain nombre d'hypotheses de programmes de centrales nucleaires de types differents. Ces programmes correspondent a l'utilisation de tonnages d'uranium et de thorium de l'ordre de grandeur de ceux qui seront probablement produits par la France dans les quinze prochaines annees. Comme il est possible de batir un programme de centrales nucleaires, comportant a la fois plusieurs filieres suivant des variantes en nombre infini, on s'est contente d'examiner successivement les resultats ous si on utilisait exclusivement l

  19. Trace element emissions from coal

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-09-15

    Trace elements are emitted during coal combustion. The quantity, in general, depends on the physical and chemical properties of the element itself, the concentration of the element in the coal, the combustion conditions and the type of particulate control device used, and its collection efficiency as a function of particle size. Some trace elements become concentrated in certain particle streams following combustion such as bottom ash, fly ash, and flue gas particulate matter, while others do not. Various classification schemes have been developed to describe this partitioning behaviour. These classification schemes generally distinguish between: Class 1: elements that are approximately equally concentrated in the fly ash and bottom ash, or show little or no fine particle enrichment, examples include Mn, Be, Co and Cr; Class 2: elements that are enriched in the fly ash relative to bottom ash, or show increasing enrichment with decreasing particle size, examples include As, Cd, Pb and Sb; Class 3: elements which are emitted in the gas phase (primarily Hg (not discussed in this review), and in some cases, Se). Control of class 1 trace elements is directly related to control of total particulate matter emissions, while control of the class 2 elements depends on collection of fine particulates. Due to the variability in particulate control device efficiencies, emission rates of these elements can vary substantially. The volatility of class 3 elements means that particulate controls have only a limited impact on the emissions of these elements.

  20. Shale oil combustion

    International Nuclear Information System (INIS)

    Al-dabbas, M.A.

    1992-05-01

    A 'coutant' carbon steel combustion chamber cooled by water jacket was conslructed to burn diesel fuel and mixlure of shale oil and diesel fuels. During experimental work nir fuel ratio was determined, temperaturces were measured using Chromel/ Almel thermocouple, finally the gasous combustion product analysis was carricd out using gas chromatograph technique. The constructed combustion chamber was operating salisfactory for several hours of continous work. According to the measurements it was found that: the flame temperature of a mixture of diesel and shale oil fuels was greater than the flame temperature of diesel fuel. and the sulfer emissious of a mixture of diesel and shale oil fuels was higher than that of diesel fuel. Calculation indicated that the dry gas energy loss was very high and the incomplete combustion energy loss very small. (author). 23 refs., 35 figs

  1. Shale oil combustion

    Energy Technology Data Exchange (ETDEWEB)

    Al-dabbas, M A

    1992-05-01

    A `coutant` carbon steel combustion chamber cooled by water jacket was conslructed to burn diesel fuel and mixlure of shale oil and diesel fuels. During experimental work nir fuel ratio was determined, temperaturces were measured using Chromel/ Almel thermocouple, finally the gasous combustion product analysis was carricd out using gas chromatograph technique. The constructed combustion chamber was operating salisfactory for several hours of continous work. According to the measurements it was found that: the flame temperature of a mixture of diesel and shale oil fuels was greater than the flame temperature of diesel fuel. and the sulfer emissious of a mixture of diesel and shale oil fuels was higher than that of diesel fuel. Calculation indicated that the dry gas energy loss was very high and the incomplete combustion energy loss very small. (author). 23 refs., 35 figs.

  2. Indoor combustion and asthma.

    Science.gov (United States)

    Belanger, Kathleen; Triche, Elizabeth W

    2008-08-01

    Indoor combustion produces both gases (eg, nitrogen dioxide, carbon monoxide) and particulate matter that may affect the development or exacerbation of asthma. Sources in the home include both heating devices (eg, fireplaces, woodstoves, kerosene heaters, flued [ie, vented] or nonflued gas heaters) and gas stoves for cooking. This article highlights the recent literature examining associations between exposure to indoor combustion and asthma development and severity. Since asthma is a chronic condition affecting both children and adults, both age groups are included in this article. Overall, there is some evidence of an association between exposure to indoor combustion and asthma, particularly asthma symptoms in children. Some sources of combustion such as coal stoves have been more consistently associated with these outcomes than other sources such as woodstoves.

  3. Sandia Combustion Research Program

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, S.C.; Palmer, R.E.; Montana, C.A. (eds.)

    1988-01-01

    During the late 1970s, in response to a national energy crisis, Sandia proposed to the US Department of Energy (DOE) a new, ambitious program in combustion research. Shortly thereafter, the Combustion Research Facility (CRF) was established at Sandia's Livermore location. Designated a ''user facility,'' the charter of the CRF was to develop and maintain special-purpose resources to support a nationwide initiative-involving US inventories, industry, and national laboratories--to improve our understanding and control of combustion. This report includes descriptions several research projects which have been simulated by working groups and involve the on-site participation of industry scientists. DOE's Industry Technology Fellowship program, supported through the Office of Energy Research, has been instrumental in the success of some of these joint efforts. The remainder of this report presents results of calendar year 1988, separated thematically into eleven categories. Referred journal articles appearing in print during 1988 and selected other publications are included at the end of Section 11. Our traditional'' research activities--combustion chemistry, reacting flows, diagnostics, engine and coal combustion--have been supplemented by a new effort aimed at understanding combustion-related issues in the management of toxic and hazardous materials.

  4. Sanitary effects of fossil fuels; Effets sanitaires des combustibles fossiles

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-01

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

  5. 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

    particle number concentration increased slightly with increasing load, at the same time the fine mode particles became smaller. This was probably caused by different degree of particle coagulation as the residence time in the boiler was changed. The mean diameter during combustion of forest residue was around 100 nm compared to 70-80 nm for dry wood and pellets, while the total number was close to constant. This explains the differences in mass concentration found in the impactor measurements. The concentrations of CO and THC was highest for the dry wood fuel, the PAH concentration was highest for pellets combustion in boiler 4, however this boiler was poorly tuned at the time of measurement. The PAH concentration was 5 times higher during combustion of dry wood compared to forest residue. The concentration of CO, THC and PAH varied to a great extend. The high concentrations were measured in boilers running at a low load. The concentration of particle organic carbon was less than 15% of PMI for all fuels. However we used heated primary dilution, which inhibits the condensation of organic components into, the particle phase. A significant fraction of the emitted organic carbon may condense to the particle phase during dilution after the stack or after being oxidized in the atmosphere. We also measured elemental carbon in the particle phase. The contribution to PM1 was as high as 25-30% during pellets combustion at low load and 8% at low load during combustion of dry wood. In all other cases the EC-concentration was less than 3% of PMI. PIXE and lon-chromatography confirmed that alkali-salts were the dominant chemical species. PIXE analysis revealed that emitted amounts of heavy metals such as Zn, Cd and Pb are strongly dependent on the type of the fuel used. Forest residues gave high emissions of Zn, Cd and Pb, while pellets gave very high emissions of Cd and Zn. The fuel with the lowest emissions of heavy metals was dry wood. This again could be related to ash content in

  6. Des Connaissances Aux Politiques

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les synergies ont été mises en commun au fur et à mesure des progrès de la recherche. .... Recherche normative (sur le rôle et la performance des institutions .... Système national d'information sur la gestion environnementale connecté à 19 ...... Un fort contrôle centralisé sur l'élaboration des politiques nationales peut ...

  7. Transient flow combustion

    Science.gov (United States)

    Tacina, R. R.

    1984-01-01

    Non-steady combustion problems can result from engine sources such as accelerations, decelerations, nozzle adjustments, augmentor ignition, and air perturbations into and out of the compressor. Also non-steady combustion can be generated internally from combustion instability or self-induced oscillations. A premixed-prevaporized combustor would be particularly sensitive to flow transients because of its susceptability to flashback-autoignition and blowout. An experimental program, the Transient Flow Combustion Study is in progress to study the effects of air and fuel flow transients on a premixed-prevaporized combustor. Preliminary tests performed at an inlet air temperature of 600 K, a reference velocity of 30 m/s, and a pressure of 700 kPa. The airflow was reduced to 1/3 of its original value in a 40 ms ramp before flashback occurred. Ramping the airflow up has shown that blowout is more sensitive than flashback to flow transients. Blowout occurred with a 25 percent increase in airflow (at a constant fuel-air ratio) in a 20 ms ramp. Combustion resonance was found at some conditions and may be important in determining the effects of flow transients.

  8. Non-Destructive Testing of Plutonium-Enriched Fuel Rods; Controles non Destructifs de Barreaux Combustibles Enrichis au Plutonium; Nedestruktivnyj-kontrol' toplivnykh sterzhnej''obogashchennykh plutoniem; Ensayo no Destructivo de Elementos Combustibles Enriquecidos en Plutonio

    Energy Technology Data Exchange (ETDEWEB)

    Libotte, P.; Inniger, H.; Leblanc, J. M. [Centre D' Etude de l' Energie Nucleaire, Societe Belge pour l' Industrie Nucleaire, S.A. (Belgonucleaire), Mol (Belgium)

    1965-09-15

    ultrasonically by the pulse-echo technique. The respective advantages of the various non-destructive techniques are studied in relation to the required accuracy and to their possible application to the automated inspection of plutonium fuel rods fabricated on an industrial scale. (author) [French] La Societe belge pour l'industrie nucleaire (BelgoNucleaire) et le Centre d'etude de l'energie nucleaire (CEN) etudient sous contrat, en cooperation avec la Commission de l'EURATOM, l'utilisation du plutonium dans les reacteurs de puissance a eau pressurisee. Dans le cadre des recherches entreprises, differentes techniques de controle non destructif ont ete mises au point en vue d'evaluer la qualite des barreaux combustibles fabriques. Les essais non destructifs mis au point et decrits dans le memoire sont utilises essentiellement pour le controle des dimensions et de la qualite des tubes de gainage, de l'integrite des soudures, de l'etancheite des barreaux, de la densite du materiau combustible et de sa repartition, de l'enrichissement en plutonium et de sa distribution radiale et axiale dans le barreau combustible. Les methodes utilisees pour ces essais non destructifs comportent principalement les examens par radiographie, par autoradiographie, par gammagraphie et par les ultrasons. Le document reprend le principe de chacune des mesures realisees, et decrit dans chaque cas l'appareillage utilise et les techniques operatoires appliquees en vue d'obtenir les sensibilites et precisions desirees. La technique utilisee pour la radiographie permet de deceler des defauts de l'ordre de 50 a 60 {mu}m dans les soudures d'extremite des barreaux combustibles. Les combustibles etant densifies par vibration de trois fractions de poudre dense, dont la fraction fine seule comporte l'enrichissement en plutonium, il est essentiel que la repartition de ce dernier, de meme que la distribution de la densite, soient relevees avec precision. Le comptage du rayonnement gamma emergent emis par le plutonium

  9. Évaluation des pratiques agricoles des légumes feuilles : le cas des ...

    African Journals Online (AJOL)

    SARAH

    30 sept. 2017 ... ... de Biochimie et Immunologie Appliquée, Centre de Recherche en Sciences Biologiques, Alimentaires et .... l'intoxication des agriculteurs et des consommateurs, ... source d'alimentation en eau et au pouvoir d'achat des.

  10. Combustion and regulation; Combustion et reglementation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This conference was organized after the publication of the French by-law no 2010 relative to combustion installations and to the abatement of atmospheric pollution. Five topics were discussed during the conference: the new regulations, their content, innovations and modalities of application; the means of energy suppliers to face the new provisions and their schedule; the manufacturers proposals for existing installations and the new equipments; the administration control; and the impact of the new measures on exploitation and engineering. Twenty papers and 2 journal articles are reported in these proceedings. (J.S.)

  11. Combustible structural composites and methods of forming combustible structural composites

    Science.gov (United States)

    Daniels, Michael A.; Heaps, Ronald J.; Steffler, Eric D.; Swank, W. David

    2013-04-02

    Combustible structural composites and methods of forming same are disclosed. In an embodiment, a combustible structural composite includes combustible material comprising a fuel metal and a metal oxide. The fuel metal is present in the combustible material at a weight ratio from 1:9 to 1:1 of the fuel metal to the metal oxide. The fuel metal and the metal oxide are capable of exothermically reacting upon application of energy at or above a threshold value to support self-sustaining combustion of the combustible material within the combustible structural composite. Structural-reinforcing fibers are present in the composite at a weight ratio from 1:20 to 10:1 of the structural-reinforcing fibers to the combustible material. Other embodiments and aspects are disclosed.

  12. Optical Tomography in Combustion

    DEFF Research Database (Denmark)

    Evseev, Vadim

    spectral measurements at several line-of-sights with a view to applications for tomographic measurements on full-scale industrial combustion systems. The system was successfully applied on industrial scale for simultaneous fast exhaust gas temperature measurements in the three optical ports of the exhaust......D project, it was also important to investigate the spectral properties of major combustion species such as carbon dioxide and carbon monoxide in the infrared range at high temperatures to provide the theoretical background for the development of the optical tomography methods. The new software....... JQSRT 113 (2012) 2222, 10.1016/j.jqsrt.2012.07.015] included in the PhD thesis as an attachment. The knowledge and experience gained in the PhD project is the first important step towards introducing the advanced optical tomography methods of combustion diagnostics developed in the project to future...

  13. Internal combustion engine

    Science.gov (United States)

    Baker, Quentin A.; Mecredy, Henry E.; O'Neal, Glenn B.

    1991-01-01

    An improved engine is provided that more efficiently consumes difficult fuels such as coal slurries or powdered coal. The engine includes a precombustion chamber having a portion thereof formed by an ignition plug. The precombustion chamber is arranged so that when the piston is proximate the head, the precombustion chamber is sealed from the main cylinder or the main combustion chamber and when the piston is remote from the head, the precombustion chamber and main combustion chamber are in communication. The time for burning of fuel in the precombustion chamber can be regulated by the distance required to move the piston from the top dead center position to the position wherein the precombustion chamber and main combustion chamber are in communication.

  14. Transportation of radioactive elements

    International Nuclear Information System (INIS)

    Thubert, Francis; Rentien, Guy; Jacquet, Michel

    1981-01-01

    The production and marketing of artificial radioactive elements engaged in by the 'Office des Rayonnements Ionisants' requires the use of specially designed packagings and assorted means of transport. The authors begin by describing the different kinds of products involved and the forms of packagings needed, and go on to discuss the various means of transport used, underlining the fact that, in terms of number and gravity, the incidents that have occurred to date have indeed been few and far between [fr

  15. Caracterisation environnementale des emissions atmospheriques d'une source fixe et creation d'un outil de gestion dynamique =

    Science.gov (United States)

    Fournier, Marie-Claude

    Une caracterisation des emissions atmospheriques provenant des sources fixes en operation, alimentees au gaz et a l'huile legere, a ete conduite aux installations visees des sites no.1 et no.2. La caracterisation et les calculs theoriques des emissions atmospheriques aux installations des sites no.1 et no.2 presentent des resultats qui sont en dessous des valeurs reglementaires pour des conditions d'operation normales en periode hivernale et par consequent, a de plus fortes demandes energetiques. Ainsi, pour une demande energetique plus basse, le taux de contaminants dans les emissions atmospheriques pourrait egalement etre en dessous des reglementations municipales et provinciales en vigueur. Dans la perspective d'une nouvelle reglementation provinciale, dont les termes sont discutes depuis 2005, il serait souhaitable que le proprietaire des infrastructures visees participe aux echanges avec le Ministere du Developpement Durable, de l'Environnement et des Parcs (MDDEP) du Quebec. En effet, meme si le principe de droit acquis permettrait d'eviter d'etre assujetti a la nouvelle reglementation, l'application de ce type de principe ne s'inscrit pas dans ceux d'un developpement durable. L'âge avance des installations etudiees implique la planification d'un entretien rigoureux afin d'assurer les conditions optimales de combustion en fonction du type de combustible. Des tests de combustion sur une base reguliere sont donc recommandes. Afin de supporter le processus de suivi et d'evaluation de la performance environnementale des sources fixes, un outil d'aide a la gestion de l'information environnementale a ete developpe. Dans ce contexte, la poursuite du developpement d'un outil d'aide a la gestion de l'information environnementale faciliterait non seulement le travail des personnes affectees aux inventaires annuels mais egalement le processus de communication entre les differents acteurs concernes tant intra- qu'inter-etablissement. Cet outil serait egalement un bon

  16. Fuel and combustion stratification study of Partially Premixed Combustion

    OpenAIRE

    Izadi Najafabadi, M.; Dam, N.; Somers, B.; Johansson, B.

    2016-01-01

    Relatively high levels of stratification is one of the main advantages of Partially Premixed Combustion (PPC) over the Homogeneous Charge Compression Ignition (HCCI) concept. Fuel stratification smoothens heat release and improves controllability of this kind of combustion. However, the lack of a clear definition of “fuel and combustion stratifications” is obvious in literature. Hence, it is difficult to compare stratification levels of different PPC strategies or other combustion concepts. T...

  17. Aerosols from biomass combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T

    2001-07-01

    This report is the proceedings of a seminar on biomass combustion and aerosol production organised jointly by the International Energy Agency's (IEA) Task 32 on bio energy and the Swiss Federal Office of Energy (SFOE). This collection of 16 papers discusses the production of aerosols and fine particles by the burning of biomass and their effects. Expert knowledge on the environmental impact of aerosols, formation mechanisms, measurement technologies, methods of analysis and measures to be taken to reduce such emissions is presented. The seminar, visited by 50 participants from 11 countries, shows, according to the authors, that the reduction of aerosol emissions resulting from biomass combustion will remain a challenge for the future.

  18. High Gravity (g) Combustion

    Science.gov (United States)

    2006-02-01

    UNICORN (Unsteady Ignition and Combustion with Reactions) code10. Flame propagation in a tube that is 50-mm wide and 1000-mm long (similar to that...turbine engine manufacturers, estimating the primary zone space heating rate. Both combustion systems, from Company A and Company B, required a much...MBTU/atm-hr-ft3) Te m pe ra tu re R is e (K ) dP/P = 2% dP/P = 2.5% dP/P = 3% dP/P = 3.5% dP/P = 4% Company A Company B Figure 13: Heat Release Rate

  19. Alcohol combustion chemistry

    KAUST Repository

    Sarathy, Mani

    2014-10-01

    Alternative transportation fuels, preferably from renewable sources, include alcohols with up to five or even more carbon atoms. They are considered promising because they can be derived from biological matter via established and new processes. In addition, many of their physical-chemical properties are compatible with the requirements of modern engines, which make them attractive either as replacements for fossil fuels or as fuel additives. Indeed, alcohol fuels have been used since the early years of automobile production, particularly in Brazil, where ethanol has a long history of use as an automobile fuel. Recently, increasing attention has been paid to the use of non-petroleum-based fuels made from biological sources, including alcohols (predominantly ethanol), as important liquid biofuels. Today, the ethanol fuel that is offered in the market is mainly made from sugar cane or corn. Its production as a first-generation biofuel, especially in North America, has been associated with publicly discussed drawbacks, such as reduction in the food supply, need for fertilization, extensive water usage, and other ecological concerns. More environmentally friendly processes are being considered to produce alcohols from inedible plants or plant parts on wasteland. While biofuel production and its use (especially ethanol and biodiesel) in internal combustion engines have been the focus of several recent reviews, a dedicated overview and summary of research on alcohol combustion chemistry is still lacking. Besides ethanol, many linear and branched members of the alcohol family, from methanol to hexanols, have been studied, with a particular emphasis on butanols. These fuels and their combustion properties, including their ignition, flame propagation, and extinction characteristics, their pyrolysis and oxidation reactions, and their potential to produce pollutant emissions have been intensively investigated in dedicated experiments on the laboratory and the engine scale

  20. Combustibility of tetraphenylborate solids

    International Nuclear Information System (INIS)

    Walker, D.D.

    1989-01-01

    Liquid slurries expected under normal in-tank processing (ITP) operations are not ignitible because of their high water content. However, deposits of dry solids from the slurries are combustible and produce dense, black smoke when burned. The dry solids burn similarly to Styrofoam and more easily than sawdust. It is the opinion of fire hazard experts that a benzene vapor deflagration could ignite the dry solids. A tetraphenylborate solids fire will rapidly plug the waste tank HEPA ventilation filters due to the nature of the smoke produced. To prevent ignition and combustion of these solids, the waste tanks have been equipped with a nitrogen inerting system

  1. Studies in combustion dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Koszykowski, M.L. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this program is to develop a fundamental understanding and a quantitative predictive capability in combustion modeling. A large part of the understanding of the chemistry of combustion processes comes from {open_quotes}chemical kinetic modeling.{close_quotes} However, successful modeling is not an isolated activity. It necessarily involves the integration of methods and results from several diverse disciplines and activities including theoretical chemistry, elementary reaction kinetics, fluid mechanics and computational science. Recently the authors have developed and utilized new tools for parallel processing to implement the first numerical model of a turbulent diffusion flame including a {open_quotes}full{close_quotes} chemical mechanism.

  2. Combustion stratification for naphtha from CI combustion to PPC

    NARCIS (Netherlands)

    Vallinayagam, R.; Vedharaj, S.; An, Y.; Dawood, A.; Izadi Najafabadi, M.; Somers, L.M.T.; Johansson, B.H.

    2017-01-01

    This study demonstrated the change in combustion homogeneity from conventional diesel combustion via partially premixed combustion towards HCCI. Experiments are performed in an optical diesel engine at a speed of 1200 rpm with diesel fuel. Single injection strategy is employed and the fuel is

  3. Etude de la pollution des eaux des oueds Seybouse et Mellah ...

    African Journals Online (AJOL)

    Anhydrite et le Gypse sont en sur-saturation (IS>O). Par consequent, ceci provoque la sedimentation de ces elements en series evaporitiques. La Halite est en sous-saturation (ISdes eaux en ...

  4. Proportioning of {sup 79}Se and {sup 126}Sn long life radionuclides in the fission products solutions coming from spent fuels processing; Dosage des radionucleides a vie longue {sup 79}Se et {sup 126}Sn dans les solutions de produits de fission issues du traitement des combustibles nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Comte, J

    2001-11-01

    The determination of radionuclides present in waste resulting from the nuclear fuel reprocessing is a request from the regulatory authorities to ensure an optimal management of the storage sites. Long-lived radionuclides (T{sub 1/2} > 30 years) are particularly concerned owing to the fact that their impact must be considered for the long term. Safety studies have established a list of long-lived radionuclides (LLRN) whose quantification is essential for the management of the disposal site. Among these, several are pure {beta} emitters, present at low concentration levels in complex matrices. Their determination, by radiochemical method or mass spectrometry, involves selective chemical separations from the others {beta}/{gamma} emitters and from the measurement interfering elements. The work undertaken in this thesis relates to the development of analytical methods for the determination of two long-lived radionuclides: selenium 79 and tin 126, in acid solutions of fission products present in nuclear fuel reprocessing plant. For selenium 79, a {beta} emitter with a half live estimated to be 10{sup 6} years, the bibliography describes different chemical separation methods including precipitation, liquid-liquid extraction and chromatography on ionic resins. After optimisation on a synthetic solution, two of these techniques, precipitation by potassium iodine and separation with ion exchange resins were applied to a genuine solution of fission products at Cogema La Hague. The results showed that only the ion exchange method allows us to obtain a solution sufficiently decontaminated (FD{beta}{gamma} = 250) with a significant selenium recovery yield (85%). This separation allows the measurement of the {sup 79}Se by electrothermal vaporization coupled with inductively coupled plasma mass spectrometry (ETV-ICP/MS), after transfer of the samples to CEA/Cadarache. The concentration of {sup 79}Se measured is 0,42 mg/L in the solution of fission products with an isotopic ratio

  5. Gestion des risques

    CERN Document Server

    Louisot, Jean-Paul

    2009-01-01

    Depuis le début du lie siècle, la gestion des risques connaît une véritable révolution culturelle. Jusqu'alors fonction technique, centrée autour de l'achat de couverture d'assurances, elle est devenue une discipline managériale et transversale : une valise d'instruments que chaque manager doit connaître et appliquer quels que soient son domaine de compétence et ses missions au sein de l'organisation. En effet, la gestion des risques est une culture qui doit être assimilée par chacun des acteurs. C'est précisément l'ambition des 101 questions rassemblées dans cet ouvrage : apporter à chaque manager d'entreprise, de collectivité, d'établissement de santé..., des réponses claires au " pourquoi " et au " comment " : Comment identifier les risques ? Comment analyser les risques ? Quels sont les objectifs de la gestion des risques ? Une carte des risques pour quoi faire ? Pourquoi faut-il financer les risques ? Les entreprises ont-elles des responsabilités pénales ? En quoi consiste la gestion...

  6. Toxicology of Biodiesel Combustion products

    Science.gov (United States)

    1. Introduction The toxicology of combusted biodiesel is an emerging field. Much of the current knowledge about biological responses and health effects stems from studies of exposures to other fuel sources (typically petroleum diesel, gasoline, and wood) incompletely combusted. ...

  7. La gouvernance des risques naturels et la problematique des ...

    African Journals Online (AJOL)

    Depuis quelques années, la gouvernance des risques naturels dus aux inondations remet en cause les processus de mise en oeuvre des politiques urbaines et la qualité de la structure des aménagements dans les grandes villes du Golfe de Guinée. La perception de la gouvernance et l'application des politiques de ...

  8. The Heat of Combustion of Tobacco and Carbon Oxide Formation

    Directory of Open Access Journals (Sweden)

    Norman AB

    2014-12-01

    Full Text Available Recent studies demonstrated a relationship between mass burn rates of straight-grade cigarettes and heats of combustion of the tobacco materials. In the present work, relationships between measured heats of combustion and elemental composition of the tobacco materials were further analyzed. Heats of combustion measured in oxygen were directly correlated with the carbon and hydrogen content of the tobacco materials tested. Ash content of the materials was inversely related to the heats of combustion. The water insoluble residues from exhaustively extracted tobacco materials showed higher heats of combustion and higher carbon content than the non-extracted materials, confirming a direct relationship between carbon content and heat of combustion. A value for the heat of formation of tobacco was estimated (1175 cal/g from the heat of combustion data and elemental analysis results. The estimated value for heat of formation of tobacco appears to be constant regardless of the material type. Heat values measured in air were uniformly lower than the combustion heats in oxygen, suggesting formation of CO and other reaction products. Gases produced during bomb calorimetry experiments with five tobacco materials were analyzed for CO and CO2 content. When the materials were burned in oxygen, no CO was found in the gases produced. Measured heats of combustion matched estimates based on CO2 found in the gas and conversion of the sample hydrogen content to water. Materials burned in air produced CO2 (56% to 77% of the sample carbon content and appreciable amounts of CO (7% to 16% of the sample carbon content. Unburned residue containing carbon and hydrogen was found in the air combustion experiments. Estimated heat values based on amounts of CO and CO2 found in the gas and water formed from the hydrogen lost during combustion in air were higher than the measured values. These observations indicate formation of products containing hydrogen when the materials

  9. Combustion: an oil spill mitigation tool

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-11-01

    The technical feasibility of using combustion as an oil spill mitigation tool was studied. Part I of the two-part report is a practical guide oriented toward the needs of potential users, while Part II is the research or resource document from which the practical guidance was drawn. The study included theoretical evaluations of combustion of petroleum pool fires under the effects of weathering and an oil classification system related to combustion potential. The theoretical analysis of combustion is balanced by practical experience of oil burning and case history information. Decision elements are provided which can be used as a guide for technical evaluations of a particular oil spill situation. The rationale for assessing technical feasibility is given in the context of other alternatives available for response to an oil spill. A series of research and technology development concepts are included for future research. The ethics of using oil burning are discussed as issues, concerns, and tradeoffs. A detailed annotated bibliography is appended along with a capsule review of a decade of oil burning studies and other support information.

  10. Underground treatment of combustible minerals

    Energy Technology Data Exchange (ETDEWEB)

    Sarapuu, E

    1954-10-14

    A process is described for treating oil underground, consisting in introducing several electrodes spaced one from the other in a bed of combustibles underground so that they come in electric contact with this bed of combustibles remaining insulated from the ground, and applying to the electrodes a voltage sufficient to produce an electric current across the bed of combustibles, so as to heat it and create an electric connection between the electrodes on traversing the bed of combustibles.

  11. Supersonic Combustion Ramjet Research

    Science.gov (United States)

    2012-08-01

    was in collaboration with Prof. R. Bowersox (Texas A&M University) and Dr. K. Kobayashi ( Japanese Aerospace Exploration Agency, JAXA). 4.2 Ignition... cinema stereoscopic PIV system for the measurement of micro- and meso-scale turbulent premixed flame dynamics,” Paper B13, 5th US Combustion

  12. Infrared monitoring of combustion

    International Nuclear Information System (INIS)

    Bates, S.C.; Morrison, P.W. Jr.; Solomon, P.R.

    1991-01-01

    In this paper, the use of Fourier Transform Infrared (FT-IR) spectroscopy for combustion monitoring is described. A combination of emission, transmission, and reflection FT-IR spectroscopy yields data on the temperature and composition of the gases, surfaces and suspended particles in the combustion environment. Detection sensitivity of such trace exhaust gases as CO, CO 2 , SO 2 , NO x , and unburned hydrocarbons is at the ppm level. Tomographic reconstruction converts line-of-sight measurements into spatially resolved temperature and concentration data. Examples from various combustion processes are used to demonstrate the capabilities of the technique. Industrial measurements are described that have been performed directly in the combustion zone and in the exhaust duct of a large chemical recovery boiler. Other measurements of hot slag show how FT-IR spectroscopy can determine the temperature and optical properties of surfaces. In addition, experiments with water droplets show that transmission FT-IR data yield spectra that characterize particle size and number density

  13. Combustible dust tests

    Science.gov (United States)

    The sugar dust explosion in Georgia on February 7, 2008 killed 14 workers and injured many others (OSHA, 2009). As a consequence of this explosion, OSHA revised its Combustible Dust National Emphasis (NEP) program. The NEP targets 64 industries with more than 1,000 inspections and has found more tha...

  14. Global Methodology to Integrate Innovative Models for Electric Motors in Complete Vehicle Simulators Méthodologie générale d’intégration de modèles innovants de moteurs électriques dans des simulateurs véhicules complets

    Directory of Open Access Journals (Sweden)

    Abdelli A.

    2011-11-01

    . Comment reduire les emissions moyennes de CO2 des vehicules particuliers a 120 g/km en 2012 et 95 g/km en 2020 comme le prevoit l’accord conclu entre la Commission Europeenne et les constructeurs europeens ? Cette question a reponses multiples preoccupe a l’heure actuelle l’ensemble du monde automobile. L’electrification des vehicules semble etre une des solutions les plus pertinentes, ce qui pousse les constructeurs a envisager des vehicules hybrides de plus en plus innovants. Cette solution, theoriquement tres interessante, complexifie encore un peu plus les groupes moto-propulseurs des vehicules, ce qui necessite l’utilisation d’outils de simulation adequats pour reduire les couts et les durees de developpement. La simulation systeme, outil deja primordial dans le processus de developpement des moteurs a combustion interne, devient alors incontournable. Pour etudier ce type d’architectures hybrides complexes, et a l’instar des modeles physiques developpes pour le moteur a combustion interne, la simulation systeme doit se doter de modeles predictifs comparables pour les machines electriques. Des leurs specifications, ces modeles doivent integrer certaines contraintes tres exigeantes sur les temps de simulation, contrainte garantissant par la suite une plus large utilisation des simulateurs, notamment pour le developpement et la validation de strategies de controle. L’objectif de ce papier est donc de presenter une methodologie generale de developpement de modeles de machines electriques, modeles ayant pour objectif final d’etre integres dans un simulateur vehicule complet. Cette methodologie met en scene differents types de modelisations (modeles elements finis, modeles de caracterisation, modele de simulation permettant un compromis temps de calcul – precision adequat. Cette methodologie a ete deployee avec succes pour la modelisation d’un moteur synchrone a aimants permanents. A l’issue du processus de modelisation, ce dernier a ete integre

  15. Particulate and gaseous emissions from residential biomass combustion

    International Nuclear Information System (INIS)

    Boman, Christoffer

    2005-04-01

    Biomass is considered to be a sustainable energy source with significant potentials for replacing electricity and fossil fuels, not at least in the residential sector. However, present wood combustion is a major source of ambient concentrations of hydrocarbons (e.g. VOC and PAH) and particulate matter (PM) and exposure to these pollutants have been associated with adverse health effects. Increased focus on combustion related particulate emissions has been seen concerning the formation, characteristics and implications to human health. Upgraded biomass fuels (e.g. pellets) provide possibilities of more controlled and optimized combustion with less emission of products of incomplete combustion (PICs). For air quality and health impact assessments, regulatory standards and evaluations concerning residential biomass combustion, there is still a need for detailed emission characterization and quantification when using different fuels and combustion techniques. This thesis summarizes the results from seven different papers. The overall objective was to carefully and systematically study the emissions from residential biomass combustion with respect to: i) experimental characterization and quantification, ii) influences of fuel, appliance and operational variables and iii) aspects of ash and trace element transformations and aerosol formation. Special concern in the work was on sampling, quantification and characterization of particulate emissions using different appliances, fuels and operating procedures. An initial review of health effects showed epidemiological evidence of potential adverse effect from wood smoke exposure. A robust whole flow dilution sampling set-up for residential biomass appliances was then designed, constructed and evaluated, and subsequently used in the following emission studies. Extensive quantifications and characterizations of particulate and gases emissions were performed for residential wood and pellet appliances. Emission factor ranges for

  16. Economical analysis to utilize MTR fuel elements using silicides in research reactors; Analisis economico sobre el uso de elementos combustibles MTR a base de siliciuros en reactores de investigacion

    Energy Technology Data Exchange (ETDEWEB)

    Bergallo, Juan E; Novara, Oscar E; Adelfang, Pablo [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Combustibles Nucleares

    2000-07-01

    According to international programs on reducing enrichment in research reactors and the necessity to maintain their operation, new fuel elements have been developed in order to meet both objectives. Thus, U-Si alloy fuel elements for research reactors are becoming of greater interest for the international markets. It became necessary to make an economic study about the convenience of introducing this type of fuel elements in the RA-3 reactor and to know the potentiality of this fuel. The economical behavior of the reactor operation has been evaluated comparing the actual U{sub 3}O{sub 8} nuclear fuel cycle with U{sub 3}Si{sub 2} nuclear fuels. Results obtained show that the main economical factor to determine the change of fuels is the cost of fabrication, and the change is advisable up to an 80% difference. The other factors related to the cost of nuclear fuel cycle are not relevant or have real minor impacts. (author)

  17. G2 and G3 reactors design; Description des reacteurs G2 et G3

    Energy Technology Data Exchange (ETDEWEB)

    Herreng,; Ertaud,; Pasquet, [Societe Alsacienne de Constructions Mecaniques (France)

    1958-07-01

    classique a trois etages (pressions 10,3: 2 et 0,5 kg/cm{sup 2}). On peut condenser la vapeur, en cas d'arret d'un groupe turbo-alternateur, sans modifier le regime de la pile. Des circuits annexes servent a assurer une epuration continue du CO{sub 2}, son stockage et sa vidange. La commande du reacteur est assuree par la manoeuvre de 49 barres en carbure de bore. La regulation de l'ensemble a pose des problemes difficiles dont les solutions seront completees par l'experience du fonctionnement. Des conferences speciales seront consacrees aux elements de combustibles et a la detection des ruptures de gaines. (auteur)

  18. Numerical simulations of stationary and transient spray combustion for aircraft gas turbine applications

    OpenAIRE

    Fossi, Athanase Alain

    2017-01-01

    Le développement des turbines à gaz d’aviation actuelles et futures est principalement axé sur la sécurité, la performance, la minimisation de la consommation de l’énergie, et de plus en plus sur la réduction des émissions d’espèces polluantes. Ainsi, les phases de design de moteurs sont soumises auxaméliorations continues par des études expérimentales et numériques. La présente thèse se consacre à l’étude numérique des phases transitoires et stationnaires de la combustion au sein d’une turbi...

  19. Inter-laboratory comparison of elemental analysis and gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS). Part I: delta13C measurements of selected compounds for the development of an isotopic Grob-test.

    Science.gov (United States)

    Serra, F; Janeiro, A; Calderone, G; Rojas, J M Moreno; Rhodes, C; Gonthier, L A; Martin, F; Lees, M; Mosandl, A; Sewenig, S; Hener, U; Henriques, B; Ramalho, L; Reniero, F; Teixeira, A J; Guillou, C

    2007-03-01

    This study was directed towards investigating suitable compounds to be used as stable isotope reference materials for gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) calibration. Several compounds were selected from those used in the 'Grob-test' mixture. Oxygen- and nitrogen-containing substances were added to these compounds to allow the mixture to be used as a possible multi-isotopic calibration tool for 2H/1H, 13C/12C, 15N/14N and 18O/16O ratio determinations. In this paper we present the results of delta13C measurements performed by the consortium of the five laboratories taking part in this inter-calibration exercise. All the compounds were individually assessed for homogeneity, short-term stability and long-term stability by means of EA-IRMS, as required by the bureau communitaire de reference (BCR) Guide for Production of Certified Reference Materials. The results were compared then with the GC-C-IRMS measurements using both polar and non-polar columns, and the final mixture of selected compounds underwent a further certification exercise assessing limits of accuracy and reproducibility under specified GC-C-IRMS conditions. Copyright 2007 John Wiley & Sons, Ltd.

  20. Low emission internal combustion engine

    Science.gov (United States)

    Karaba, Albert M.

    1979-01-01

    A low emission, internal combustion compression ignition engine having a cylinder, a piston movable in the cylinder and a pre-combustion chamber communicating with the cylinder near the top thereof and in which low emissions of NO.sub.x are achieved by constructing the pre-combustion chamber to have a volume of between 70% and 85% of the combined pre-chamber and main combustion chamber volume when the piston is at top dead center and by variably controlling the initiation of fuel injection into the pre-combustion chamber.

  1. Photonique des Morphos

    CERN Document Server

    Berthier, Serge

    2010-01-01

    La photonique est déjà présente dans notre vie quotidienne, et on attend maintenant que la manipulation des photons permette aussi le traitement logique des informations. Cependant, l’élément de base qui permet cette manipulation de la lumière, le cristal photonique, est d’une réalisation complexe et mal contrôlée. Dans la course à la maîtrise de la lumière, les structures photoniques naturelles ont beaucoup à nous apprendre. C’est ce que nous montre Serge Berthier qui étudie dans ce livre la structure des écailles des Morphos. Tenant compte de l’essor récent des approches biomimétiques, il présente de manière détaillée plus de dix-huit techniques expérimentales utilisées pour ses analyses, ainsi que les diverses approches théoriques développées pour la modélisation de structures multi-échelles complexes. Première étude quasi-exhaustive des structures fines d’un genre et des propriétés optiques ainsi que colorimétriques générées, ce livre fournit aux entomologiste...

  2. Droit des organisations internationales

    CERN Document Server

    Sorel, Jean-Marc; Ndior, Valère

    2013-01-01

    Cet ouvrage collectif offre aux enseignants et chercheurs en droit international, aux praticiens et aux étudiants, une analyse actualisée du droit des organisations internationales. Il dresse en cinq parties un tableau, illustré par des exemples variés, des problématiques que soulève le phénomène polymorphe d institutionnalisation de la société internationale. La première partie est consacrée au phénomène des « organisations internationales », sous l angle à la fois de l institutionnalisation progressive des relations internationales et de la difficulté à cerner une catégorie unifiée. La deuxième partie rend compte de la création, de la disparition et des mutations des organisations internationales, ici envisagées comme systèmes institutionnels et ordres juridiques dérivés. La troisième partie analyse l autonomie que l acquisition de la personnalité juridique et de privilèges et immunités, un organe administratif intégré, un personnel ou un budget propres confèrent aux organi...

  3. The Origin and Nature of Radioactive Wastes in the United States Atomic Energy Programme; Origine et Nature des Dechets Radioactifs de l'Execution des Programmes d'Energie Atomique aux Etats-Unis; 041f 0420 041e 0418 0421 0425 041e 0416 0414 ; Origen y Naturaleza de los Desechos Radiactivos en el Programa de Energia Atomica de los Estados Unidos

    Energy Technology Data Exchange (ETDEWEB)

    Bruce, F. R. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    1960-07-01

    cartouches de combustible faiblement enrichi consistent ordinairement en un element d'uranium gaine d'aluminium, de zirconium ou d'acier inoxydable et donnent lieu a deux sortes de dechets. Les uns sont des dechets a activite moyenne contenant environ 0,1% de produits de fission et proviennent de la dissolution chimique. Les autres sont des dechets a activite elevee contenant tous les autres produits de fission dans une solution d'acide nitrique etendue. Le volume des dechets condenses varie de 0,8 litre par kilogramme d'uranium pour les combustibles peu enrichis a 500 litres par kilogramme d'uranium pour les combustibles fortement enrichis, le volume de l'ensemble des dechets d'intensite elevee et intermediaire qui, a ce que l'on prevoit, proviendront des centrales nucleaires aux Etats-Unis. est d'environ 5 litres par kilogramme d'uranium en moyenne. Aux Etats-Unis, on estime qu'en 1970, les centrales nucleaires auront produit environ 3 milliards de curies contenues dans 27 millions de litres de solution, et en l'an 2000, 60 milliards de curies contenues dans 1,1 milliard de litres de solution. En raison de leur composition, les dechets provenant des reacteurs de puissance posent des problemes nouveaux d'entreposage et d'elimination. (author) [Spanish] La composicion de los desechos que se forman como consecuencia de la produccion de energia nucleoelectrica depende en primer lugar del tratamiento empleado en la regeneracion del combustible y, en segundo, de la composicion inicial de este. Por cada unidad de volumen de desechos de actividad elevada, obtenidos en la extraccion mediante disolventes, se forman 5 y 100 volumenes, respectivamente, de desechos de actividad media y baja. Los desechos que se producen en la regeneracion de los combustibles muy enriquecidos son muy voluminosos por contener el diluente del combustible. Los combustibles poco enriquecidos consisten habitualmente en un nucleo de uranio revestido de aluminio, zirconio o acero inoxidable, y producen dos

  4. Développement d'une approche couplée Automates Cellulaires – Eléments Finis pour la modélisation du développement des structures de grains en soudage TIG A coupled Cellular Automaton – Finite Element approach for the modelling of grain structure development in TIG welding

    Directory of Open Access Journals (Sweden)

    Chen Shijia

    2013-11-01

    Full Text Available Dans le domaine du soudage, les propriétés finales du cordon sont fortement liées à la structure de grains développée au cours des procédés de fusion / resolidification. La maîtrise des propriétés de l'assemblage final passe ainsi par une amélioration de la connaissance de sa structure de ce domaine. Dans cet objectif, un modèle couplé Automates Cellulaires – Eléments Finis est proposé pour simuler le développement, en volume, de cette structure, dans le cadre du soudage TIG. Ce modèle est appliqué au soudage d'acier Duplex 2202 et l'évolution de la structure de grains selon les paramètres procédés est discutée. In the welding area, the final properties of the weld bead are mainly induced by the grain structure developed during the melting and solidification steps. The mastery of the properties of the joining will be achieved with a better knowledge of the developed grain structure. A 3D coupled Cellular Automaton – Finite Element model is proposed in order to simulate the grains development in TIG process. This model is applied to the welding of a duplex stainless steel grade. The grain structure evolution is discussed for the various process parameters.

  5. Hydrogen assisted diesel combustion

    Energy Technology Data Exchange (ETDEWEB)

    Lilik, Gregory K.; Boehman, Andre L. [The EMS Energy Institute, The Pennsylvania State University, University Park, PA 16802 (United States); Zhang, Hedan; Haworth, Daniel C. [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Herreros, Jose Martin [Escuela Tecnica Superior de Ingenieros Industriales, Universidad de Castilla La-Mancha, Avda. Camilo Jose Cela s/n, 13071 Ciudad Real (Spain)

    2010-05-15

    Hydrogen assisted diesel combustion was investigated on a DDC/VM Motori 2.5L, 4-cylinder, turbocharged, common rail, direct injection light-duty diesel engine, with a focus on exhaust emissions. Hydrogen was substituted for diesel fuel on an energy basis of 0%, 2.5%, 5%, 7.5%, 10% and 15% by aspiration of hydrogen into the engine's intake air. Four speed and load conditions were investigated (1800 rpm at 25% and 75% of maximum output and 3600 rpm at 25% and 75% of maximum output). A significant retarding of injection timing by the engine's electronic control unit (ECU) was observed during the increased aspiration of hydrogen. The retarding of injection timing resulted in significant NO{sub X} emission reductions, however, the same emission reductions were achieved without aspirated hydrogen by manually retarding the injection timing. Subsequently, hydrogen assisted diesel combustion was examined, with the pilot and main injection timings locked, to study the effects caused directly by hydrogen addition. Hydrogen assisted diesel combustion resulted in a modest increase of NO{sub X} emissions and a shift in NO/NO{sub 2} ratio in which NO emissions decreased and NO{sub 2} emissions increased, with NO{sub 2} becoming the dominant NO{sub X} component in some combustion modes. Computational fluid dynamics analysis (CFD) of the hydrogen assisted diesel combustion process captured this trend and reproduced the experimentally observed trends of hydrogen's effect on the composition of NO{sub X} for some operating conditions. A model that explicitly accounts for turbulence-chemistry interactions using a transported probability density function (PDF) method was better able to reproduce the experimental trends, compared to a model that ignores the influence of turbulent fluctuations on mean chemical production rates, although the importance of the fluctuations is not as strong as has been reported in some other recent modeling studies. The CFD results confirm

  6. Synthesis of functional materials in combustion reactions

    Science.gov (United States)

    Zhuravlev, V. D.; Bamburov, V. G.; Ermakova, L. V.; Lobachevskaya, N. I.

    2015-12-01

    The conditions for obtaining oxide compounds in combustion reactions of nitrates of metals with organic chelating-reducing agents such as amino acids, urea, and polyvinyl alcohol are reviewed. Changing the nature of internal fuels and the reducing agent-to-oxidizing agent ratio makes possible to modify the thermal regime of the process, fractal dimensionality, morphology, and dispersion of synthesized functional materials. This method can be used to synthesize simple and complex oxides, composites, and metal powders, as well as ceramics and coatings. The possibilities of synthesis in combustion reactions are illustrated by examples of αand γ-Al2O3, YSZ composites, uranium oxides, nickel powder, NiO and NiO: YSZ composite, TiO2, and manganites, cobaltites, and aluminates of rare earth elements.

  7. Heavy water reactors physics; Physique des reacteurs a eau lourde

    Energy Technology Data Exchange (ETDEWEB)

    Girard, Y; Lourme, P; Naudet, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    particulieres aux reseaux comportant le refroidissement par gaz mesures de distributions fines de densite (indices de spectre, etc mesures sur des reseaux ou des echantillons comportant de l'uranium a des enrichissements differents ou du plutonium. Dans la deuxieme partie on passe en revue les etudes de caractere theorique. L'ensemble des resultats a permis d'asseoir des methodes de calcul qui ont accru notablement la comprehension des phenomenes neutroniques dans les reseaux, et d'etablir un formulaire rendant compte des experiences sur reseaux neufs et capable de predire correctement l'evolution des proprietes neutroniques du combustible avec l'irradiation. Quelques etudes particulieres aux reacteurs de puissance sont mentionnees. (auteurs)

  8. Review of Development Status of Nuclear Superheat; Expose sur l'etat actuel des travaux concernant la surchauffe nucleaire; Obzor razrabotki voprosa o yadernykh peregrevatelyakh; Estudio de los progresos realizados en niateria de sobrecalentamiento nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Imhoff, D. H.; Pennington, R. T. [General Electric Company, San Jose, CA (United States)

    1963-10-15

    fuel irradiation performance, in-pile and out-of-pile uniform and localized corrosion evaluations, results from thermal superheat critical experiments, results from experimental heat-transfer testing and a brief appraisal of the economic incentives of the separate superheat reactor, integral superheat reactor, and mixed-spectrum superheat reactor design studies. (b) A brief description is given of the USAEC-Sponsored ESADA-VESR nuclear superheat fuel development programme. The development tasks, the initial core superheat fuel-element design, the range of experimental variables, and the expected results for the three-year fuel development programme are discussed. (author [French] Depuis 1959, la Societe General Electric s'occupe activement de mettre au point la surchauffe nucleaire dans les reacteurs ralentis a l'eau ordinaire. A cette epoque, le ''Superheat Advance Demonstration Experiment'' (SADE), finance par la societe, a permis d'obtenir, pour la premiere fois aux Etats-Unis, de la vapeur surchauffee par un dispositif nucleaire. Les auteurs du memoire font le point de la situation actuelle concernant la surchauffe nucleaire. Ils decrivent, dans une premiere partie, les trois principales installations de surchauffe nucleaire utilisees par la General Electric et, dans la seconde, les deux principaux programmes de recherches sur la surchauffe ainsi que les resultats les plus importants obtenus jusqu'ici dans ce domaine. 1. Principales installations pour les experiences de surchauffe: a) Breve description du SADE utilise dans le reacteur a eau bouillante de Vallecitos (VBWR), avec tableaux des conditions dans lesquelles se deroulent les experiences, et des elements combustibles irradies pendant la periode comprise entre mai 1959 et juin 1962; puis examen critique des resultats les plus importants ainsi obtenus. b) Breve description de l' ''Expanded Superheat Advance Demonstration Experiment'' (E-SADE) installe dans le reacteur de Vallecitos, avec tableaux des

  9. Status of fossil fuel reserves; Etat des reserves des combustibles fossiles

    Energy Technology Data Exchange (ETDEWEB)

    Laherrere, J

    2005-07-01

    Reserves represent the sum of past and future productions up to the end of production. In most countries the reserve data of fields are confidential. Therefore, fossil fuel reserves are badly known because the published data are more political than technical and many countries make a confusion between resources and reserves. The cumulated production of fossil fuels represents only between a third and a fifth of the ultimate reserves. The production peak will take place between 2020 and 2050. In the ultimate reserves, which extrapolate the past, the fossil fuels represent three thirds of the overall energy. This document analyses the uncertainties linked with fossil fuel reserves: reliability of published data, modeling of future production, comparison with other energy sources, energy consumption forecasts, reserves/production ratio, exploitation of non-conventional hydrocarbons (tar sands, extra-heavy oils, bituminous shales, coal gas, gas shales, methane in overpressure aquifers, methane hydrates), technology impacts, prices impact, and reserves growth. (J.S.)

  10. Santé des adolescents et des jeunes au Burkina Faso : état des ...

    African Journals Online (AJOL)

    Il s'est agi d'une étude évaluative ayant utilisé une revue documentaire associée à une interview des acteurs clés et un atelier de validation et d'identification des interventions pertinentes pour un plan stratégique national. La situation de la santé des adolescents et des jeunes est caractérisée par des grossesses précoces ...

  11. Ash behaviour in fluidized bed gasification and combustion: release of harmful trace elements and the behavior of alkalis; Tuhkan muuntuminen leijukerroskaasutuksessa ja -poltossa: Haitallisten hivenmetallien vapautuminen ja alkalien kaeyttaeytyminen

    Energy Technology Data Exchange (ETDEWEB)

    Kauppinen, E; Valmari, T [VTT Chemical Technology, Espoo (Finland)

    1997-10-01

    During 1996 the behaviour of alkaline metals (K and Na) during circulating fluidized bed combustion of forest residue was studied in a real-scale plant using aerosol measurement instruments (filters, impactor, DMA). Prior to heat exchangers (850 deg C) the ash mass-concentration was 1.0 - 1.3 g/Nm{sup 3} with 1 % of ash forming constituents as vapours. At least 98 % of sulphur, over 90 % of sodium and over 80 % of potassium were found in particulate phase prior to heat exchangers. On the other hand, at least 80 % of the chlorine was in vapour phase. 98 % of the ash was in coarse (> 0.3 {mu}m) particles. Coarse ash particles had an irregular surface structure often consisting of fine primary particles. The remaining 2 % was observed in fine particles of about 0.1 {mu}m. Both rounded and cornered (suggesting crystal structure) fine particles were found. The fine particles were composed of alkali chlorides and sulphates, mainly of KCl. About 80 % of the ash on mass basis was deposited onto heat exchanger surfaces when soot-blowing was not carried out. Practically all of the particles larger than 10 {mu}m were deposited. The deposition was less significant for smaller particles. The fine particle concentration before and after the heat exchangers was the same within the experimental inaccuracy. The deposited fraction of potassium, sodium and sulphur was about the same than that of the total ash: However, the deposition of chlorine was much lower since the chlorine content was low in the coarse particles that were deposited most effectively. (orig.)

  12. Combustion strategy : United Kingdom

    Energy Technology Data Exchange (ETDEWEB)

    Greenhalgh, D. [Heriot-Watt Univ., Edingburgh, Scotland (United Kingdom). School of Engineering and Physical Sciences

    2009-07-01

    The United Kingdom's combustion strategy was briefly presented. Government funding sources for universities were listed. The United Kingdom Research Councils that were listed included the Arts and Humanities Research Council (AHRC) and the Biotechnology and Biological Sciences Research Council (BBSRC); the Engineering and Physical Sciences Research Council (EPSRC); the Economic and Social Research Council; the Medical Research Council; the Natural Environment Research Council; and the Science and Technology Facilities Council. The EPSRC supported 65 grants worth 30.5 million pounds. The combustion industry was noted to be dominated by three main players of which one was by far the largest. The 3 key players were Rolls-Royce; Jaguar Land Rover; and Doosan Babcock. Industry and government involvement was also discussed for the BIS Technology Strategy Board, strategy technology areas, and strategy application areas.

  13. Aerosols from biomass combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T.

    2001-07-01

    This report is the proceedings of a seminar on biomass combustion and aerosol production organised jointly by the International Energy Agency's (IEA) Task 32 on bio energy and the Swiss Federal Office of Energy (SFOE). This collection of 16 papers discusses the production of aerosols and fine particles by the burning of biomass and their effects. Expert knowledge on the environmental impact of aerosols, formation mechanisms, measurement technologies, methods of analysis and measures to be taken to reduce such emissions is presented. The seminar, visited by 50 participants from 11 countries, shows, according to the authors, that the reduction of aerosol emissions resulting from biomass combustion will remain a challenge for the future.

  14. A review of internal combustion engine combustion chamber process studies at NASA Lewis Research Center

    Science.gov (United States)

    Schock, H. J.

    1984-01-01

    The performance of internal combustion stratified-charge engines is highly dependent on the in-cylinder fuel-air mixing processes occurring in these engines. Current research concerning the in-cylinder airflow characteristics of rotary and piston engines is presented. Results showing the output of multidimensional models, laser velocimetry measurements and the application of a holographic optical element are described. Models which simulate the four-stroke cycle and seal dynamics of rotary engines are also discussed.

  15. Plasma Assisted Combustion

    Science.gov (United States)

    2007-02-28

    Tracking an individual streamer branch among others in a pulsed induced discharge J. Phys. D: Appl. Phys. 35 2823--9 [29] van Veldhuizen E M and Rutgers...2005) AIAA–2005–0405. [99] E.M. Van Veldhuizen (ed) Electrical Discharges for Environmental Purposes: Fun- damentals and Applications (New York: Nova...Vandooren J, Van Tiggelen P J 1977 Reaction Mechanism and Rate Constants in Lean Hydrogen–Nitrous Oxide Flames Combust. Flame 28 165 [201] Dean A M, Steiner

  16. Fluid-bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, G.; Schoebotham, N.

    1981-02-01

    In Energy Equipment Company's two-stage fluidized bed system, partial combustion in a fluidized bed is followed by burn-off of the generated gases above the bed. The system can be retrofitted to existing boilers, and can burn small, high ash coal efficiently. It has advantages when used as a hot gas generator for process drying. Tests on a boiler at a Cadbury Schweppes plant are reported.

  17. Combustion science and engineering

    CERN Document Server

    Annamalai, Kalyan

    2006-01-01

    Introduction and Review of Thermodynamics Introduction Combustion Terminology Matter and Its Properties Microscopic Overview of Thermodynamics Conservation of Mass and Energy and the First Law of Thermodynamics The Second Law of Thermodynamics Summary Stoichiometry and Thermochemistry of Reacting Systems Introduction Overall Reactions Gas Analyses Global Conservation Equations for Reacting Systems Thermochemistry Summary Appendix Reaction Direction and Equilibrium Introduction Reaction Direction and Chemical Equilibrium Chemical Equilibrium Relations Vant Hoff Equation Adi

  18. Distribution and removal of transuranic elements and cerium deposited by the inhalation route; Distribution et elimination des transuraniens et du cerium deposes par l'intermediaire des voies respiratoires; Raspredelenie transuranovykh ehlementov i tseriya, otkladyvayushchikhsya v rezul'tate vdykhaniya i ikh udalenie; Distribucion y eliminacion de elementos transuranicos y de cerio depositados por inhalacion

    Energy Technology Data Exchange (ETDEWEB)

    Bair, W. J.; Tombropoulos, E. G.; Park, J. F. [Hanford Atomic Products Operation, General Electric Company, Richland, WA (United States)

    1963-02-15

    Tissue distribution and excretion of inhaled radioactive isotopes varied with the chemical form and the particle size of the aerosols. In dogs, 30 d after inhalation of plutonium nitrate, 70% of the body burden was in the lungs, 10% in liver, and 15% in the skeleton. After inhalation of P{sup 239} O{sub 2} aerosols with a Count Median Diameter (CMD) of 0.12{mu}m, 71% of the body burden was in the lungs, 3% in the bronchial lymph nodes, 4.4% in muscle, 1.3% in skeleton, and 20% was uniformly distributed throughout all remaining tissues. After inhalation of P{sup 239} O{sub 2} aerosols with CMD's of 0.3 to 0.6 {mu}m; the lungs contained 98%, the bronchial lymph nodes about 1% and all other tissues the remaining one per cent. These data and the analysis of urine and faeces defined the relative importance of the three routes by which inhaled radioactive isotopes were cleared from the lung, e.g. movement up the trachea by ciliary action followed by excretion in the faeces, transport across the alveolar membrane and redistribution in other tissue with gradual excretion in urine and transport to the bronchial lymph nodes which accumulate inhaled insoluble materials. Therapy agents were tested that would be expected to increase the clearance of radioactive isotopes from the lung by routes which would avoid accumulation in other, perhaps more radiosensitive tissues. These include chelating agents, wetting agents, irritants, sympathomimetic, parasympathomimetic, parasympatholytic and antihistamine drugs. Diethylenetriamine-pentaacetic acid (DTPA), a chelating agent, administered by aerosols or intraperitoneally caused rapid transport of Ce{sup 144} -Pr{sup 144} from the lung and from the body via urinary excretion. One month after exposure to Ce{sup 144} O{sub 2} treated rats and dogs retained less than 10% of the Ce{sup 144} -Pr{sup 144} levels of untreated animals. (author) [French] La distribution dans les tissus et l'excretion des radioisotopes inhales varient selon la

  19. Dental Encounter System (DES)

    Data.gov (United States)

    Department of Veterans Affairs — Dental Encounter System (DES) is an automated health care application designed to capture critical data about the operations of VA Dental Services. Information on...

  20. Diethylstilbestrol (DES) and Cancer

    Science.gov (United States)

    ... DES-exposed grandchildren have? Researchers are also studying possible health effects among women and men who are the children ... for unexposed men. In addition, researchers are studying possible health effects on the grandchildren of mothers who were exposed ...

  1. Table des illustrations

    OpenAIRE

    2016-01-01

    Tableaux Dates d’inauguration des grands hôtels japonais entre 1860 et 1945… 19 Histoire, tourisme et hôtellerie en Corée depuis les années 1870… 59-60 Dates d’inauguration des grands hôtels chinois depuis 1863… 84 Les hôtels de luxe et leurs capacités d’hébergement en Corée en 2000… 103 Les flux de personnes suscités par les hôtels « super luxe » de Séoul en 2000… 105 L’activité des grands hôtels à Séoul en 1999 (en wons)… 106 Propriété et gestion des grands hôtels à Séoul en 1999…. 110 La c...

  2. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    potential and surface properties of their mixtures were investigated, in an ... suppose that the electrostatic repulsive interactions between the two anion ... concentration, et de la conformation des ..... proteins and polysaccharides in solutions,.

  3. Emissions from laboratory combustion of wildland fuels: Emission factors and source profiles

    Science.gov (United States)

    L.-W. Anthony Chen; Hans Moosmuller; W. Patrick Arnott; Judith C. Chow; John G. Watson; Ronald A. Susott; Ronald E. Babbitt; Cyle E. Wold; Emily N. Lincoln; Wei Min Hao

    2007-01-01

    Combustion of wildland fuels represents a major source of particulate matter (PM) and light-absorbing elemental carbon (EC) on a national and global scale, but the emission factors and source profiles have not been well characterized with respect to different fuels and combustion phases. These uncertainties limit the accuracy of current emission inventories, smoke...

  4. Issues in waste combustion

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, Lennart; Robertson, Kerstin; Tullin, Claes [Swedish National Testing and Research Inst., Boraas (Sweden); Sundquist, Lena; Wrangensten, Lars [AaF-Energikonsult AB, Stockholm (Sweden); Blom, Elisabet [AaF-Processdesign AB, Stockholm (Sweden)

    2003-05-01

    The main purpose of this review is to provide an overview of the state-of-the-art on research and development issues related to waste combustion with relevance for Swedish conditions. The review focuses on co-combustion in grate and fluidised bed furnaces. It is primarily literature searches in relevant databases of scientific publications with to material published after 1995. As a complement, findings published in different report series, have also been included. Since the area covered by this report is very wide, we do not claim to cover the issues included completely and it has not been possitile to evaluate the referred studies in depth. Basic knowledge about combustion issues is not included since such information can be found elsewhere in the literature. Rather, this review should be viewed as an overview of research and development in the waste-to-energy area and as such we hope that it will inspire scientists and others to further work in relevant areas.

  5. Novel approaches in advanced combustion characterization of fuels for advanced pressurized combustion

    Energy Technology Data Exchange (ETDEWEB)

    Aho, M.; Haemaelaeinen, J. [VTT Energy (Finland); Joutsenoja, T. [Tampere Univ. of Technology (Finland)

    1996-12-01

    This project is a part of the EU Joule 2 (extension) programme. The objective of the research of Technical Research Centre of Finland (VTT) is to produce experimental results of the effects of pressure and other important parameters on the combustion of pulverized coals and their char derivates. The results can be utilized in modelling of pressurized combustion and in planning pilot-scale reactors. The coals to be studied are Polish hvb coal, French lignite (Gardanne), German anthracite (Niederberg) and German (Goettelbom) hvb coal. The samples are combusted in an electrically heated, pressurized entrained flow reactor (PEFR), where the experimental conditions are controlled with a high precision. The particle size of the fuel can vary between 100 and 300 {mu}m. The studied things are combustion rates, temperatures and sizes of burning single coal and char particles. The latter measurements are performed with a method developed by Tampere University of Technology, Finland. In some of the experiments, mass loss and elemental composition of the char residue are studied in more details as the function of time to find out the combustion mechanism. Combustion rate of pulverized (140-180 {mu}m) Gardanne lignite and Niederberg anthracite were measured and compared with the data obtained earlier with Polish hvb coal at various pressures, gas temperatures, oxygen partial pressures and partial pressures of carbon dioxide in the second working period. In addition, particle temperatures were measured with anthracite. The experimental results were treated with multivariable partial least squares (PLS) method to find regression equation between the measured things and the experimental variables. (author)

  6. The Diesel Combustion Collaboratory: Combustion Researchers Collaborating over the Internet

    Energy Technology Data Exchange (ETDEWEB)

    C. M. Pancerella; L. A. Rahn; C. Yang

    2000-02-01

    The Diesel Combustion Collaborator (DCC) is a pilot project to develop and deploy collaborative technologies to combustion researchers distributed throughout the DOE national laboratories, academia, and industry. The result is a problem-solving environment for combustion research. Researchers collaborate over the Internet using DCC tools, which include: a distributed execution management system for running combustion models on widely distributed computers, including supercomputers; web-accessible data archiving capabilities for sharing graphical experimental or modeling data; electronic notebooks and shared workspaces for facilitating collaboration; visualization of combustion data; and video-conferencing and data-conferencing among researchers at remote sites. Security is a key aspect of the collaborative tools. In many cases, the authors have integrated these tools to allow data, including large combustion data sets, to flow seamlessly, for example, from modeling tools to data archives. In this paper the authors describe the work of a larger collaborative effort to design, implement and deploy the DCC.

  7. Internal combustion engine using premixed combustion of stratified charges

    Science.gov (United States)

    Marriott, Craig D [Rochester Hills, MI; Reitz, Rolf D [Madison, WI

    2003-12-30

    During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

  8. Trace element content of human head hair as a function of sex, age, sphere of life, colour of the hair and localisation. Der Spurenelementgehalt des menschlichen Kopfhaares in Abhaengigkeit von Geschlecht, Alter, Lebensraum, Haarfarbe und Lokalisation

    Energy Technology Data Exchange (ETDEWEB)

    Simaitis, M.

    1981-01-01

    Hair specimens from 247 probands were examined by absorption spectroscopy following wet ashing with nitric acid and hydrogen peroxide. The specimens were not pre-treated. The investigations related to the elements Zn, Mg, Ca, Fe, Pb, Cu, Al, Cd, Sb, Tl, As and Hg. For each element the optimal working conditions were established and laid down in tables. The influences of sex, age and origin were investigated. Differences regarding sex and age were found for the elements Mg, Ca, Cd and Al. The results can be useful in the detection of environmental impacts and intoxications with heavy metals and metalloids and to mark such collectives off from normally exposed ones, as well as in the diagnosis of some diseases. On the basis of the trace element distribution in the hair it may even be possible to trace sources of heavy metal emissions. The deviations from the trace element content are also useful for the purposes of forensic medicine and crime detection.

  9. La revolution des savants

    CERN Document Server

    Chavanne, A

    1989-01-01

    Premiere cassette : - 1666 : impact de la creation de l'Academie des Sciences par Colbert, trente ans apres le proces de Galile, et au moment des disparitions de Pascal, Descartes et Fermat. Elle dirigee par le hollandais Huyggens jusqu'a sa fuite de France au moment de la revocation de l'Edit de Nantes. - 1750 : l'Encyclopedie (ou "Dictionnaire raisonne des Sciences, des Arts et des Metiers") de Diderot et d'Alembert, soutenus par Malherbes, Buffon, Condorcet et Rousseau. - 1789 : Revolution francaise. - 8 aout 1793 : l'Assemblee, par une declaration de Marat, dissout l'Academie des Sciences. Celle-ci continue cependant ses travaux pour les poids et mesures jusqu'en 1795. - la Terreur : la condamnation a mort, pas au nom d'une "Revolution qui n'a pas besoin de savants" mais pour d'autres raisons, de trois grands hommes de science : Lavoisier, Bailly et Condorcet. - 1793-1794 : Au printemps 93, le Comite de Salut Publique s'inquiete du demi-million de soldats etrangers de toutes les pays frontaliers qui essai...

  10. Development of flameless combustion; Desarrollo de la combustion sin flama

    Energy Technology Data Exchange (ETDEWEB)

    Flores Sauceda, M. Leonardo; Cervantes de Gortari, Jaime Gonzalo [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: 8344afc@prodigy.net.mx; jgonzalo@servidor.unam.mx

    2010-11-15

    The paper intends contribute to global warming mitigation joint effort that develops technologies to capture the CO{sub 2} produced by fossil fuels combustion and to reduce emission of other greenhouse gases like the NO{sub x}. After reviewing existing combustion bibliography is pointed out that (a) touches only partial aspects of the collective system composed by Combustion-Heat transfer process-Environment, whose interactions are our primary interest and (b) most specialists think there is not yet a clearly winning technology for CO{sub 2} capture and storage. In this paper the study of combustion is focused as integrated in the aforementioned collective system where application of flameless combustion, using oxidant preheated in heat regenerators and fluent gas recirculation into combustion chamber plus appropriated heat and mass balances, simultaneously results in energy saving and environmental impact reduction. [Spanish] El trabajo pretende contribuir al esfuerzo conjunto de mitigacion del calentamiento global que aporta tecnologias para capturar el CO{sub 2} producido por la combustion de combustibles fosiles y para disminuir la emision de otros gases invernadero como NOx. De revision bibliografica sobre combustion se concluye que (a) trata aspectos parciales del sistema compuesto por combustion-proceso de trasferencia de calor-ambiente, cuyas interacciones son nuestro principal interes (b) la mayoria de especialistas considera no hay todavia una tecnologia claramente superior a las demas para captura y almacenaje de CO{sub 2}. Se estudia la combustion como parte integrante del mencionado sistema conjunto, donde la aplicacion de combustion sin flama, empleando oxidante precalentado mediante regeneradores de calor y recirculacion de gases efluentes ademas de los balances de masa y energia adecuados, permite tener simultaneamente ahorros energeticos e impacto ambiental reducido.

  11. CONTRIBUTION A L’ETUDE SUR L’EMISSION ET LE TRANSFERT DANS LES SOLS DES ELEMENTS TRACES METALLIQUES (ETM) EN DOMAINE ROUTIER (la route national N° 23, la wilaya de Tiaret.

    OpenAIRE

    AMCHA, Mustapha

    2014-01-01

    Le présent travail apporte une contribution à l'étude de l'impact de la pollution métallique sur trois sols issus de chaussées proches d`une route nationale. Ces sols sont choisis à partir d'emplacements principaux de trafic journalier moyen important de véhicules pour l'ensemble des deux sens de circulation. L'analyse physico-chimique nous a permis de caractériser les sols étudiés : -Les trois sols ont une texture semblable à celle d'un sable limoneux.-Les trois sols sont légèrement basiq...

  12. Effects of Gamma Radiation on the Constituents of Wheat Flour; Action des Rayons Gamma sur les Elements Constitutifs de la Farine de Ble; Dejstvie gamma-luchej na sostavnye ehlementy muki; Accion de los Ratos Gamma Sobre los Elementos Constitutivos de la Harina de Trigo

    Energy Technology Data Exchange (ETDEWEB)

    Deschreider, A. R. [Laboratoire Central du Ministere des Affaires Economiques, Bruxelles (Belgium)

    1966-11-15

    certain authors have noted in the case of wheat receiving small gamma radiation doses. (author) [French] Des changements physiques, chimiques et biochimiques apparaissent dans les elements constitutifs de la farine irradiee par les rayons gamma. Ils dependent de l'origine de la farine, et sont d'autant plus importants que la dose de rayonnement est plus elevee. Les caroteno'ides de la fraction huileuse de.la farine diminuent sous l'action des radiations, puis disparaissent lorsque la dose atteint 4 Mrad. Quant aux lipides, ils sont le siege de reactions similaires a celles qui engendrent les hydroperoxydes; cependant, meme aux doses tres elevees, leur composition chimique n'est pratiquement pas affectee. La degradation importante de l'amidon indique que les polysaccharides de la farine sont les fractions les plus affectees par les irradiations. Cela entraine une augmentation des substances reductrices preexistantes et de l'indice maltose, parallele a l'elevation des doses appliquees. Mais l'accroissement de la production autolytique des sucres reducteurs est du, dans la farine irradiee, a une susceptibilite plus grande de l'amidon a l'hydrolyse par les diastases. La denaturation des polysaccharides provoque une chute de viscosite des empois d'amidon, due a l'augmentation de solubilite de l'amylopectine. En general, l'irradiation gamma diminue l'activite proteolytique de la farine et provoque, aux doses elevees, non seulement une denaturation partielle des proteines, mais egalement leur polymerisation et/ou leur condensation. Cette polymerisation peut s'expliquer par la reaction de radicaux libres avec les proteines du glut possedant des groupements -SH, et par la reaction de radicaux primaires entre eux au sein des macromolecules de proteines; ces phenomenes se produisent pendant l'irradiation. Les modifications des proteines provoquent des variations de la solubilite des albumine, gliadine et glutenine, ainsi que de la repartition centesimale des groupes qui les

  13. Description of methods for making activation detectors for use in nuclear reactors; Description des procedes de fabrication des detecteurs d'activation utilises dans les reacteurs nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Barbalat, R; Le Coguie, R; Leger, P; Salon, L; Thierry, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    A brief description of methods currently used for making activation detectors, thin films and various deposits used in nuclear reactors. The thicknesses required vary from about a few tenths of a micron to a few tenths of a millimeter. Different techniques are used for fixing the large variety of elements: rolling, moulding, painting, electrolysis, vacuum deposition, thin films, wires, enamels, protective linings, etc. (authors) [French] Expose succinct des procedes actuellement mis en oeuvre pour la realisation des detecteurs d'activation, feuilles minces et depots divers utilises dans les reacteurs nucleaires. La gamme des epaisseurs necessaires s'etendant approximativement des dixiemes de micrometre aux dixiemes de millimetre. La diversite des elements a fixer justifiant les techniques differentes selon les cas: laminage, moulage, peinture, electrolyse, depot sous vide, couches minces, fils, emaux, revetements protecteurs, etc. (auteurs)

  14. Optimization of the distribution of bars with gadolinium oxide in reactor fuel elements PWR; Optimizacion de la distribucion de barras con oxido de gadolinio en elementos combustibles para reactores PWR

    Energy Technology Data Exchange (ETDEWEB)

    Melgar Santa Cecilia, P. A.; Velazquez, J.; Ahnert Iglesias, C.

    2014-07-01

    In the schemes of low leakage, currently used in the majority of PWR reactors, it makes use of absorbent consumables for the effective control of the factors of peak, the critical concentration of initial boron and the moderator temperature coefficient. One of the most used absorbing is the oxide of gadolinium, which is integrated within the fuel pickup. Occurs a process of optimization of fuel elements with oxide of gadolinium, which allows for a smaller number of configurations with a low peak factor for bar. (Author)

  15. 3d Modeling of Combustion for Di-Si Engines Modélisation 3D de la combustion dans les moteurs à injection directe d'essence

    Directory of Open Access Journals (Sweden)

    Duclos J. P.

    2006-12-01

    Full Text Available Direct injection of gasoline is a promising concept to reduce fuel consumption of SI engines. The development of GDI engines is difficult and 3D CFD is a way to support its design. It requires models able to describe the spray and its evaporation and combustion. This paper presents a model, the ECFM, that enables to compute combustion for stratified load in the GDI engines. This model is a development of the Coherent Flame Model which includes thermal expansion effects, and is coupled with a burnt/unburnt gases conditionnal thermodynamic properties description. The model is validated by comparing measurements and computations on the GDI Mitsubishi engine in production. L'injection directe d'essence (IDE est un concept prometteur pour les moteurs à allumage commandé. La mise au point de ce type de moteur est néanmoins délicate, et le calcul 3D des chambres de combustion est un moyen d'aider à leur conception. Ceci nécessite cependant de disposer de modèles adaptés, à même de décrire le jet d'essence, son évaporation et la combustion du mélange créé. Cet article présente un modèle ECFM de simulation de la combustion dans les moteurs IDE, y compris en fonctionnement stratifié. C'est un développement du modèle flamme cohérente qui comprend des effets d'expansion thermique et est couplé avec une description conditionnelle gaz frais/gaz brûlés des grandeurs thermodynamiques. Ce modèle a été validé par rapprochement de mesures et simulations sur le moteur GDI Mitsubishi.

  16. Die entwicklung, die metamorphose, die entstehung: Die konzepte des organismus von Aristoteles bis Darwin

    Directory of Open Access Journals (Sweden)

    Kamerer Eva

    2009-01-01

    Full Text Available (nemački In diesem Aufsatz versuche ich, die Elemente verschiedener Konzepte des Organismus in der Philosophie und in der Wissenschaft zu analysieren. Die Deutungen des Organismus und der Einheit der Natur bei Aristoteles, Kant und Goethe werden als ein Beispiel der Bewegung von einem finalistischen zum antifinalistischen Bild der Natur verstanden.

  17. Study of hydrogen migration produced during the corrosion of PWR reactors fuel cans in zircaloy 4 and zirconia; Etude du transport de l`hydrogene produit lors de la corrosion des gaines d`elements combustibles des reacteurs a eau sous pression dans la zircone et le zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Aufore, L

    1997-12-12

    The corrosion of Zircaloy-4-claddings by water from the primary circuit of nuclear power plant goes hand in hand with the release of hydrogen which penetrates the oxide and then the metal. This work focuses on the mechanisms of hydrogen transport in oxide and in metal. Hydrogen transport in oxide is studied on the basis of corrosion tests performed in the autoclave at 360 deg C. These tests are performed on Zircaloy-4 claddings under different chemical conditions (pure water, and pure water with lithium hydroxide). The distribution of hydrogen in oxide film is measured by SIMS. Hydrogen profiles in the oxide are dependent on the oxide microstructure and vary with oxidation time. These observations are confirmed by experiments in which some samples, previously oxidized in the autoclave, are immersed in heavy water. In the oxide layer, two zones are observed: one external porous zone and one internal dense zone. Deuterium diffusion coefficients in dense oxide are determined using SIMS profiles and Fischer diffusion model. Hydrogen transport in metal is also studied by means of gas-phase permeation experiments. These are set up at different temperature (400-500 deg. C) and under different hydrogen pressures and make it possible to determine the hydrogen diffusion coefficients in a Zircaloy-4 cladding under experimental conditions. All these results lead us to discuss of hydrogen transport evolution in cladding during oxidation. A model taking into account hydrogen transport in oxide and in metal, and the hydrides precipitations is proposed. (author) 110 refs.

  18. Contribution des radios communautaires a l'education des ...

    African Journals Online (AJOL)

    Contribution des radios communautaires a l'education des populations rurales pour un developpement durable au Benin: etude de cas. ... Journal de la Recherche Scientifique de l'Université de Lomé. Journal Home · ABOUT THIS JOURNAL ...

  19. La convergence des rôles respectifs des relationnistes et des journalistes influence-t-elle la perception qu'ils ont les uns des autres?

    DEFF Research Database (Denmark)

    Valentini, Chiara

    2017-01-01

    la convergence des rôles respectifs des praticiens des relations publiques et des journalistes a un effet favorable sur la perception qu’ils ont les uns des autres. L’effet est plus marqué chez les praticiens des relations publiques, car leur vision de la profession en journalisme correspond à celle...

  20. Sulfur Chemistry in Combustion I

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Glarborg, Peter

    2000-01-01

    of the sulphur compounds in fossil fuels and the possibilities to remove them will be given. Then the combustion of sulphur species and their influence on the combustion chemistry and especially on the CO oxidation and the NOx formation will be described. Finally the in-situ removal of sulphur in the combustion...... process by reaction between SO2 and calcium containing sorbents and the influence on the NOx chemistry will be treated....

  1. Combustion kinetics of the coke on deactivated dehydrogenation catalysts

    NARCIS (Netherlands)

    Luo, Sha; He, Songbo; Li, XianRu; Li, Jingqiu; Bi, Wenjun; Sun, Chenglin

    2015-01-01

    The coke combustion kinetics on the deactivated catalysts for long chain paraffin dehydrogenation was studied by the thermogravimetry and differential thermogravimetry (TG–DTG) technique. The amount and H/C mole ratio of the coke were determined by the TG and elemental analysis. And the