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AbstractAbstract
[en] As part of the nuclear waste management, hulls and ends of fuel claddings are cut, compacted and put in CSD-C containers (compacted standard waste containers). Currently stored at La Hague, the waste will be stored in deep geological environment. The MA-VL waste contains RN including carbon-14, which comes from the neutron activation of nitrogen-14 and oxygen-17 present in the oxide Zircaloy. The objective of this thesis, which is taken in collaboration with EDF and AREVA, is to answer the question of the carbon-14 behavior in ZrO2 and Zr metal. This thesis is to perform numerical simulations, using the Theory of Density Functional (DFT) to model the behavior of carbon-14 in the CSD -C. The simulations are performed with multi-scale approach: 1) At atomic scale, optimization of atomic models to represent the different phases of ZrO2; identification of the insertion sites for the carbon atom in interstitial sites and substitutions of an oxygen or zirconium atom; modeling different minimum energy path for the migration of a carbon atom from one site to another by interstitial and vacancy mechanisms. 2) At macroscopic scale, determination of diffusion coefficients in pure bulk monoclinic ZrO2 and pure bulk Zr by the Monte Carlo method. (author)
[fr]
Dans le cadre de la gestion des dechets nucleaires, les coques et embouts des gaines de combustibles sont coupees, compactees et empiles dans les colis CSD-C (Colis Standards de Dechets Compactes). Actuellement entreposes a la Hague, ces dechets seront stockes en milieu geologique profond dans des alveoles en beton. Ces dechets MA-VL contiennent des RN d'interets dont le carbone-14 qui provient de l'activation neutronique de l'azote-14 et de l'oxygene-17 presents dans le Zircaloy oxyde. L'objectif de cette these, qui est menee en collaboration avec EDF et AREVA, est de repondre a la question du devenir et du comportement du carbone-14 dans ZrO2 et Zr-metal. Cette these consistera a utiliser la simulation numerique, au moyen de la Theorie de la Fonctionnelle de la Densite (DFT), afin de modeliser le comportement du carbone-14 dans les CSD-C. Les simulations sont effectue avec approche multi-echelles: 1) Echelle atomique, optimisation de modeles atomiques permettant de representer les differentes phases de ZrO2; identification des differents sites d'insertion possibles pour l'atome de carbone en sites interstitiels et en substitutions a un atome d'oxygene ou de zirconium; modelisation des differentes chemins d'energie minimum associees a la migration d'un atome de carbone d'un site a un autre par mecanismes interstitiels et lacunaires. 2) Echelle macroscopique, determination des coefficients de diffusion par la methode Monte-Carlo dans ZrO2 monoclinique pure et Zr pure. (auteur)Original Title
Etude de la diffusion du carbone dans le zirconium et la zircone en volume des gaines de combustible usees par simulations multi-echelles
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10 Dec 2015; 140 p; 96 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses; These de doctorat de l'Universite Paris-Saclay, Specialite: Aval du cycle nucleaire, radioprotection et radiochimie
Record Type
Miscellaneous
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Thesis/Dissertation
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ACTIVATION ENERGY, BINDING ENERGY, CARBON 14, COMPUTERIZED SIMULATION, DENSITY FUNCTIONAL METHOD, DENSITY OF STATES, HEXAGONAL LATTICES, INTERSTITIALS, MONOCLINIC LATTICES, MONTE CARLO METHOD, RADIONUCLIDE MIGRATION, SELF-DIFFUSION, TETRAGONAL LATTICES, TRAJECTORIES, VACANCIES, ZIRCALOY, ZIRCONIUM, ZIRCONIUM OXIDES
ALLOYS, BETA DECAY RADIOISOTOPES, BETA-MINUS DECAY RADIOISOTOPES, CALCULATION METHODS, CARBON ISOTOPES, CHALCOGENIDES, CRYSTAL DEFECTS, CRYSTAL LATTICES, CRYSTAL STRUCTURE, DIFFUSION, ELEMENTS, ENERGY, ENVIRONMENTAL TRANSPORT, EVEN-EVEN NUCLEI, ISOTOPES, LIGHT NUCLEI, MASS TRANSFER, METALS, NUCLEI, OXIDES, OXYGEN COMPOUNDS, POINT DEFECTS, RADIOISOTOPES, SIMULATION, THREE-DIMENSIONAL LATTICES, TRANSITION ELEMENT ALLOYS, TRANSITION ELEMENT COMPOUNDS, TRANSITION ELEMENTS, VARIATIONAL METHODS, YEARS LIVING RADIOISOTOPES, ZIRCONIUM ALLOYS, ZIRCONIUM BASE ALLOYS, ZIRCONIUM COMPOUNDS
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