Courson, Olivier
Universite Paris VI, Paris XI, Grenoble 1, Tours (France); Commissariat a l'energie atomique et aux energies alternatives - CEA, Institut National des Sciences et Techniques Nucleaires - INSTN (France); Commissariat a l'energie atomique et aux energies alternatives - CEA, Centre d'Etudes Nucleaires de Fontenay-aux-Roses, Service des Procedes de Haute Activite - SPHA, Groupe d'Analyse et de Controle des Procedes (France)1993
Universite Paris VI, Paris XI, Grenoble 1, Tours (France); Commissariat a l'energie atomique et aux energies alternatives - CEA, Institut National des Sciences et Techniques Nucleaires - INSTN (France); Commissariat a l'energie atomique et aux energies alternatives - CEA, Centre d'Etudes Nucleaires de Fontenay-aux-Roses, Service des Procedes de Haute Activite - SPHA, Groupe d'Analyse et de Controle des Procedes (France)1993
AbstractAbstract
[en] Within the frame of the evolution of a new nuclear waste management, notably in the case of long-life wastes, and more particularly shells and nozzles obtained after the shearing and dissolution of irradiated fuels (mechanical processing, packaging, possible causes of nozzle pollution, storage of packaged nozzles), this study addressed the assessment of highly radioactive and long-lived elements as some of these elements could be a limitation as far as deep storage is concerned. The author presents some nozzle characteristics (fuel assembly fabrication, composition, impurity content, irradiation history, isotopic compositions of materials), and then addresses the study of activation reactions. More particularly, the author studied the experimental determination of nickel 63 and niobium 94 contents. He shows that the measurement of nickel 63 is possible by liquid scintillation by using previous selective separation and chloroform-based extraction. As far as niobium is concerned, the use of a plasma torch allows contents in springs to be determined. Obtained results are close to the calculated ones. (authors)
[fr]
Devant l'importance du cout du stockage en profondeur des dechets a vie longue, une nouvelle strategie de gestion est a l'etude avec comme objectif la reduction d'ici l'an 2 000 du volume produit. Ces dechets concernent entre autres les coques et les embouts provenant du cisaillage et de la dissolution des combustibles irradies. Par leur contamination, ces deux elements sont totalement dissociables. Contrairement aux coques ou la principale contamination est provoquee par les produits de fission de l'uranium, la radioactivite des embouts provient seulement de la presence de produits d'activation des materiaux les composant. Nous pouvons envisager qu'apres un rincage a l'acide nitrique, les embouts presentent des caracteristiques radiochimiques correspondant aux specifications de l'Andra concernant les sites de stockages en surface. Il est donc interessant de connaitre une estimation des elements fortement radioactifs et de longues periodes se trouvant en fin d'irradiation. L'etude a permis de demontrer que seuls certains elements a vie longue etaient limitatifs pour un eventuel stockage en surface. C'est ainsi que les elements suivants ont attire notre attention: 60Co, 55Fe, 54Mn, 63Ni, et 94Nb. Les teneurs en nickel et niobium ont ete determinees par l'experience. La mesure du nickel 63 par scintillation liquide est possible grace a un separation selective par la dimethylglyoxime et une extraction chloroformique prealable. Quant au niobium, l'utilisation de la torche a plasma permet la determination des teneurs dans les ressorts. Les resultats experimentaux sont peu eloignes de nos calculs, toutefois, il serait utile de connaitre les repartitions axiales et longitudinales du flux au niveau de l'embout pour optimiser les calculs theoriques. En effet, les calculs d'activation effectues peuvent varier d'un facteur 5 du fait de la meconnaissance du flux dans cette region. On constate ainsi, que la difference entre l'experience et le calcul va en augmentant plus on s'eloigne de la partie basse de l'embout (partie de reference pour le flux). (auteur)Original Title
Caracterisation d'un embout d'assemblage REP en Provence (erreur sans doute: en provenance?) d'UP2: calculs d'activation des materiaux de constitution de l'embout et comparaison des resultats avec les mesures experimentales
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Jun 1993; 55 p; 113 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses; DEA Radioelements, Rayonnements, Radiochimie
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Miscellaneous
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Thesis/Dissertation
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AREVA NC, CALCULATION METHODS, CEA, COMPARATIVE EVALUATIONS, CONTAMINATION, DECONTAMINATION, LIQUID SCINTILLATION DETECTORS, NICKEL 63, PWR TYPE REACTORS, RADIATION MONITORING, RADIATION PROTECTION, RADIOACTIVE WASTE FACILITIES, RADIOACTIVE WASTE MANAGEMENT, REPROCESSING, SHIELDING MATERIALS, SPENT FUELS
BETA DECAY RADIOISOTOPES, BETA-MINUS DECAY RADIOISOTOPES, CLEANING, ENERGY SOURCES, ENRICHED URANIUM REACTORS, EVALUATION, EVEN-ODD NUCLEI, FRENCH ORGANIZATIONS, FUELS, INTERMEDIATE MASS NUCLEI, ISOTOPES, MANAGEMENT, MATERIALS, MEASURING INSTRUMENTS, MONITORING, NATIONAL ORGANIZATIONS, NICKEL ISOTOPES, NUCLEAR FACILITIES, NUCLEAR FUELS, NUCLEI, POWER REACTORS, RADIATION DETECTORS, RADIOISOTOPES, REACTOR MATERIALS, REACTORS, SCINTILLATION COUNTERS, SEPARATION PROCESSES, THERMAL REACTORS, WASTE MANAGEMENT, WATER COOLED REACTORS, WATER MODERATED REACTORS, YEARS LIVING RADIOISOTOPES
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Courson, Olivier
Paris-11 Univ., 91 - Orsay (France)1997
Paris-11 Univ., 91 - Orsay (France)1997
AbstractAbstract
[en] Technetium 99, produced with a high yield as fission product of 235U in nuclear reactors constitutes an important issue in the nuclear waste management. The rich and complex solution chemistry leads up to now to an insufficient knowledge of its behaviour in PUREX process and in environment. In order to understand the reduction mechanism of pertechnetate on mercury electrode, we have developed electrochemical techniques which use an additional time parameter to classical techniques used on mercury electrode. On micro-electrode, we have observed, for long time measurements (3D polarography), a split of the first polarographic wave into two waves, which characterizes the reduction of Tc(VII) in Tc(III) as well as a modification of the catalytic peak associated with technetium metal formation. moreover, differential capacitance determination of electrode/solution interface brings to the fore the existence of species (Tc(IV), T(0)) on mercury in the reduction zone corresponding to the following reductions: Tc(VII) -> T(III) and T(III) -> Tc(0). Moreover the Tc(III)/Tc(0) reduction brings the intermediary Tc(I) and Tc(II) which are present only for rates faster than the scan. Results obtained on microelectrodes have been confirmed on macro-electrode; the insoluble species Tc(IV) and Tc are formed during the reduction of Tc(VII) on metal. Thus, in acetate buffer media (pH=4.6), the pertechnetate reduction is characterized by the presence of absorbable species (Tc O2 hydrated,Tc). Moreover, the different electrochemical responses obtained with our techniques like 3D-polarography (waves and catalytic peaks) can be attributed to the following steps: Tc(VII)->Tc(V), Tc(IV) -> Tc(III), Tc(III) -> Tc(I) and Tc(I) -> Tc(0). The Tc(V) formation is followed by the rapid disproportionation of Tc(V) and Tc(VI) and Tc(I) reduction is associated with the proton reduction. (author)
Original Title
Etude du comportement electrochimique du technetium sur mercure en milieu acetique tamponne
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7 Nov 1997; 170 p; 124 refs., 68 figs., 19 tabs.; Theses (Ph.D)
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Miscellaneous
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Thesis/Dissertation
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BETA DECAY RADIOISOTOPES, BETA-MINUS DECAY RADIOISOTOPES, CARBOXYLIC ACIDS, CHEMICAL REACTIONS, ELEMENTS, HOURS LIVING RADIOISOTOPES, INTERMEDIATE MASS NUCLEI, INTERNAL CONVERSION RADIOISOTOPES, ISOMERIC TRANSITION ISOTOPES, ISOTOPES, MANAGEMENT, METALS, MONOCARBOXYLIC ACIDS, NUCLEI, ODD-EVEN NUCLEI, ORGANIC ACIDS, ORGANIC COMPOUNDS, OXYGEN COMPOUNDS, RADIOISOTOPES, TECHNETIUM COMPOUNDS, TECHNETIUM ISOTOPES, TRANSITION ELEMENT COMPOUNDS, WASTE MANAGEMENT, YEARS LIVING RADIOISOTOPES
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Sergeant, Claire; Holub, Guillaume; Vesvres, Marie-Helene; Mallet, Clarisse; Beauger, Aude; Chardon, Patrick; Breton, Vincent; Nero, Mireille del; Courson, Olivier; Montavon, Gilles
18th International Conference on Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere: Migration 2023. Book of abstracts2023
18th International Conference on Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere: Migration 2023. Book of abstracts2023
AbstractAbstract
[en] In this study, we focused on the study of samples from six naturally radioactive mineral springs of varying radioelement concentration gradient (<3.71 ppb U) in the Massif Central sampled in autumn, and of soil core samples from a wetland downstream of the old Rophin mine, characterised by a uranium rich layer (>1200 ppm U). The bacterial biodiversity of these samples was characterized by next generation sequencing (Illumina Miseq), targeting the 16S rRNA gene. In addition, the influence of the different physico-chemical parameters on these bacterial communities was studied. The results highlight the presence of bacterial populations specific to the environments most charged with uranium. To understand how these bacteria have adapted to these particular conditions, a culture on non-selective medium was performed for samples from these six mineral springs and a seventh with a higher concentration of uranium (15.91 ppb U); and from samples of the soil core of the wetland downstream of the former mine site. A collection of several hundred bacterial strains has been formed and identified, many of which are close to species known to be radioresistant. Some of these bacteria have been studied for their potential resistance and interaction with uranium. Indeed, the diversity of mechanisms used to resist high concentrations of uranium and other metals (biosorption, bioaccumulation, bioreduction, biomineralization) suggests that bacteria from these environments may have an impact on the migration and the toxicity of these elements into the environment
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Grambow, B.; Abdelouas, A.; Landesman, C.; Montavon, G.; Suzuki-Muresan, T.; Pierret, T.; Ollitrault, I.; Decatoire, M. (Subatech, Nantes (France)); Plas, F. (ANDRA (France)); Savoye, S. (DES/ISAS/DRMP/SPC/L3MR, CEA Centre Paris-Saclay 91191 Gif-sur-Yvette (France)); Claret, F. (BRGM, Orleans, (France)); Wittebroodt, Ch. (IRSN, Fontenay-aux-Roses (France)); Subatech, Nantes (France); ANDRA (France); CEA Centre Paris-Saclay (France); BRGM, Orleans, (France); IRSN, (France); 520 p; Sep 2023; p. 449-450; Migration 2023: 18. International Conference on Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere; Nantes (France); 24-29 Sep 2023; 2 refs. ; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses
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