Literatura académica sobre el tema "Capture des radionucléides gazeux"
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Artículos de revistas sobre el tema "Capture des radionucléides gazeux":
Van Ryckeghem, S. "Caractérisation des formes physico-chimiques des deux radionucléides principaux (18F et 11C) produits par irradiation de cible et du principal radionucléide parasite (13N) rejetés par les installations françaises de fabrication de radiopharmaceutiques au moyen d’un cyclotron". Radioprotection 56, n.º 2 (abril de 2021): 127–35. http://dx.doi.org/10.1051/radiopro/2021008.
Tesis sobre el tema "Capture des radionucléides gazeux":
Leloire, Maëva. "Utilisation de matériaux poreux de type Metal-Organic Framework (MOF) pour l’adsorption de molécules gazeuses (I2, RuO4) dans le contexte d’un accident de réacteur nucléaire". Electronic Thesis or Diss., Université de Lille (2018-2021), 2021. http://www.theses.fr/2021LILUR009.
The radiotoxic isotopes of iodine and ruthenium, such as 129I, 131I, 103Ru and 106Ru, are produced in significant quantities during nuclear fission. After a nuclear accident, these elements can be rapidly disseminated in the environment, in the form of highly volatile species such as molecular iodine (I2) or ruthenium tetroxide (RuO4). In order to limit the dispersion of these fission products, in case of a nuclear accident, filters composed by porous materials (zeolites or activated carbon) can be used. However, such porous solids have limitations during a nuclear accident. Indeed, the presence of poisonous species (for example NOx, H2O, COx) can ihhibit the capture of radiotoxic species. In addition, their relatively low porosity is often not suitable for the good trapping of large species such as RuO4. Based on these limitations, a recent class of porous materials called Metal-Organic Frameworks (MOFs) could be an effective substitute. Indeed, MOFs are hybrid materials, composed of inorganic clusters linked to each other by organic ligands. This low-density organization allows high porosity and high specific surface areas (up to 7000 m2.g-1), significantly higher than those of the usual porous solids. Although MOFs have already shown good capacities for capturing radioactive species, very little data exist on their effectiveness for trapping gaseous species (especially RuO4) and under accident conditions.In order to strengthen our knowledge of MOFs for potential use in nuclear safety, this thesis work focused on the effectiveness of some model MOFs for the capture of volatile I2 and RuO4 under accident conditions. We have highlighted the importance of the organic linker functionalization and confinement of iodine in the porous matrix. Thus, iodine creates a strong interaction with the framework of MOFs to form other iodine species of type Ix-. This transformation was notably analyzed by RAMAN spectroscopy.Following this first study, we selected the compound UiO-66_NH2 as reference filtration material to be tested in an IRSN facility called EPICUR. This one allows the manipulation of radioactive iodine (isotope-131) and the study of the confinement of iodine in within the porous framework in accidental conditions (radiation, temperature, steam). This work needs, upstream, to develop a shaping process in order to produce a MOF material with a spherical millimeter particle size. In parallel, an investigation on the resistance of this material under gamma irradiation was also undertaken in IRMA facility at IRSN. This study confirmed the excellent capacity of the solid UiO-66_NH2 in the present context. Finally, UiO-66_NH2 was also the candidate of choice for the capture of gaseous RuO4. The various analyzes (TEM, NMR) made it possible to quantify the RuO4 within the pores and to propose reaction mechanisms explaining its very good capture in UiO-66_NH2
Falaise, Clément. "Polymères de coordination : utilisation de matrices poreuses de type MOF pour la capture des radionucléides et cristallochimie des carboxylates d'actinides légers (Th, U) tétravalents". Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10115/document.
The use of nuclear energy obviously raises the question of the presence of radionuclides in the environment. Currently, their mitigation is a major issue associated with nuclear chemistry. This thesis focuses on both the trapping of radionuclides by porous solids called Metal-Organic Frameworks (MOF) and the crystal chemistry of the carboxylate of tetravalent actinides (AnIV). The academic knowledge of the reactivity of carboxylate of AnIV could help the understanding of actinides speciation in environment. We focused on the sequestration of iodine by aluminum based MOF. The functionalization (electron-donor group) of the MOF drastically enhances the iodine capture capacity. The removal of light actinides (Th and U) from aqueous solution was also investigated as well as the stability of (Al)-MOF under γ radiation. More than twenty coordination polymers based on tetravalent actinides have been synthesized and characterized by single crystal X-ray diffraction. The use of controlled hydrolysis promotes the formation of coordination polymers exhibiting polynuclear cluster ([U4], [Th6], [U6] and [U38]). In order to understand the formation of the largest cluster, the ex-situ study of the solvothermale synthesis of compound {U38} has also been investigated
Houjeij, Hanaa. "Etude expérimentale des réactions de capture/désorption des iodes gazeux (I2, CH3I) sur des aérosols environnementaux". Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0172.
Gaseous iodine I131 mainly under I2 or CH3I forms, when released into the atmosphere during a severe nuclear power plant accident may affect both human health and environment. The atmospheric dispersion models of iodine do not take into account the potential reactivity of iodine with atmospheric gas or particles species. However, the modification of the chemical speciation and/or the physical form of iodine compounds is not without consequences on the transport of iodine in the atmosphere and its health effects. Within the framework of improving the atmospheric dispersion tools of radioactive iodine, this work aims to contribute to the actual state of knowledge of atmospheric iodine chemistry by experimental approaches focusing on understanding the CH3I-aerosols and CH3I-water interaction processes.The interaction between CH3I and water at the molecular scale has been investigated using cryogenic matrix experiments supported by theoretical DFT calculations. A large excess of water regarding CH3I was used in order to mimic atmospheric conditions. Dimers and trimers of CH3I are observed despite the high water amount in the initial mixture together with mixed aggregates between CH3I and water polymers. This may be explained by the low affinity of CH3I with water. This result highlights that, in the atmosphere, gaseous CH3I and H2O will likely form aggregates of water and CH3I polymers instead of (CH3I)m-(H2O)n hetero complexes. Further, the interaction between CH3I and amorphous ice as a model of atmospheric ice have been preliminary investigated. The adsorption of CH3I on amorphous has been observed but with a complete desorption of CH3I above 47 K.Experimental study of interaction processes between gaseous iodine (CH3I) and both dry and wet NaCl as surrogate of sea salt aerosols has been carried out using Diffuse Reflectance Infrared Fourier Transformed Spectroscopy (DRIFTS). The DRIFTS spectra of NaCl surface clearly evidenced adsorbed CH3I on the NaCl surface particles. The FTIR spectra revealed new absorption bands that have been not clearly attributed. The adsorption process of CH3I on NaCl is likely a chemisorption since no desorption was observed. We have demonstrated that the adsorption of CH3I on NaCl did not reach saturation even after 5 hours of continuous flow of CH3I. CH3I capture at the NaCl surface presents a 1st order kinetics relative to its gas phase concentration. The uptake coefficients were determined to be in the order of 3 × 10-11, with a global adsorption energy of about -39 kJ.mol− 1. These results show a low probability of CH3I molecules to be captured by NaCl surface. The presence of water on the surface of NaCl seems to have no effect on the interaction between CH3I and NaCl, which is consistent with the low affinity of CH3I for water.The interactions of CH3I with various inorganic and organic powdered solids as models for atmospheric aerosols have been investigated using static reactor coupled with gas chromatography (GC) allowing the monitoring of the gas phase. We have highlighted a weak interaction between CH3I and inorganic and organic aerosols indicating a low affinity of CH3I whatever the aerosol surface composition. We hypothesis that the water content at the aerosol surface is a key parameter. So that, when released in the atmosphere, CH3I will interact very little with the surface of the aerosols and will stay in the gaseous phase. However, although in low content, a part of CH3I is irreversibly adsorbed on the surface of the halide salts that could be considered in the atmospheric iodine model to estimate potential impact
Falaise, Clément. "Polymères de coordination : utilisation de matrices poreuses de type MOF pour la capture des radionucléides et cristallochimie des carboxylates d'actinides légers (Th, U) tétravalents". Electronic Thesis or Diss., Lille 1, 2014. http://www.theses.fr/2014LIL10115.
The use of nuclear energy obviously raises the question of the presence of radionuclides in the environment. Currently, their mitigation is a major issue associated with nuclear chemistry. This thesis focuses on both the trapping of radionuclides by porous solids called Metal-Organic Frameworks (MOF) and the crystal chemistry of the carboxylate of tetravalent actinides (AnIV). The academic knowledge of the reactivity of carboxylate of AnIV could help the understanding of actinides speciation in environment. We focused on the sequestration of iodine by aluminum based MOF. The functionalization (electron-donor group) of the MOF drastically enhances the iodine capture capacity. The removal of light actinides (Th and U) from aqueous solution was also investigated as well as the stability of (Al)-MOF under γ radiation. More than twenty coordination polymers based on tetravalent actinides have been synthesized and characterized by single crystal X-ray diffraction. The use of controlled hydrolysis promotes the formation of coordination polymers exhibiting polynuclear cluster ([U4], [Th6], [U6] and [U38]). In order to understand the formation of the largest cluster, the ex-situ study of the solvothermale synthesis of compound {U38} has also been investigated
Thomas, Vincent. "Développement d’un système de mesure ultra-compact à coïncidences électron/photon pour la détection et la caractérisation de radionucléides du xénon". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS454/document.
As part of the Comprehensive nuclear Test Ban Treaty (CTBT), an International Monitoring System (IMS) has been developed. This network consists of several hundred measuring stations whose role is to detect the signatures of a clandestine nuclear test. Four types of measurements are carried out: seismic, hydroacoustic, infrasound and radionuclide. In the particular case of an underground nuclear test, only the radionuclide measurement is adequate to detect the explosion and quantify its yield. Four xenon radionuclides with long half-lives are produced during a nuclear test: the 131m-Xe, the 133m-Xe, the 133-Xe and the 135-Xe. A small proportion of these gases may diffuse through the cracks in the cavity and end up in the atmosphere. Due to atmospheric dilution, the concentrations of these four radionuclides are extremely low and therefore difficult to detect. In addition, atmospheric background continues to increase as these radioactive gases are also produced by medical radioisotope facilities and nuclear power plants. In order to strengthen the IMS, the CEA-DAM has proposed to develop an ultra-compact and mobile system for detecting xenon radionuclides, in order to be able to carry out verification measurements directly on site, and thus to avoid the problem of atmospheric dilution. This work presents the development and optimization of this system. The system was first modelled on a computer and its performances in terms of detection efficiency were simulated by the Monte-Carlo method using Geant4 software. Measurements are made in electron-photon coincidence mode. In parallel, an ultra-compact acquisition chain has been developed, as well as a communication network to synchronize in time the various digital spectrometers used for signal processing (IEEE 1588 PTP protocol). The minimum detectable concentrations of this system are less than 5 mBq/m³ for a 12 h acquisition, for the four xenon radionuclides of interest
Carette, Michel. "Etude expérimentale d'une source ionique par capture d'électrons d'atomes excités dans des états de Rydberg : application à la spectrométrie de masse de polluants atmosphériques". Aix-Marseille 1, 1999. http://www.theses.fr/1999AIX11065.
Ramirez, Santos Álvaro Andrés. "Application of membrane gas separation processes to CO2 and H2 recovery from steelmaking gases for carbon capture and use". Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0272.
Steel is produced today mainly in a blast furnace-oxygen converter process, leading to three main types of emissions: blast furnace gas (BFG), coke oven gas (COG), and converter gas (BOFG). In the framework of the VALORCO project, an analysis of the possibilities for reducing carbon emissions, combined with the valorization of emissions from the steel industry, was carried out. One of the routes studied is the production of compounds of industrial interest such as methanol, which can be produced by chemical transformation of the CO and / or CO2 contained in the emissions associated with hydrogen. The main objective of this thesis work is to evaluate the possibilities offered by the gas permeation process applied to the selective recovery of these compounds in the three types of emissions. Initially, a state of the art of the various projects dedicated to the capture (CCS) and the valorization (CCU) of the emissions in the steel industry is presented, with particular attention to the different gas separation technologies. Experimental measurements of selectivity and permeance for different temperature and pressure conditions, carried out on a dedicated bench with two commercially available membrane materials, one selective to hydrogen (glassy) and one to CO2 (rubbery), allowed a systematic parametric study by simulation of the separation performance of the process applied to the BFG, COG and BOFG. A comparison of the processes based on one or more permeation stages, including recirculation loops, was then undertaken in a Process System Engineering (PSE) environment (Aspen Plus software). The influence of the operating parameters (pressure ratio, temperature, stage cut) on the separation performance was evaluated, leading to a mapping of attainable compositions. The energy consumption and the membrane surface required for each configuration allow a techno-economic optimization of the process, on the basis of an economic model integrated to the simulation conditions
Makhloufi, Camel. "Étude expérimentale et modélisation d'un procédé de captage en CO2 en postcombustion par l'ammoniaque à l'aide de contacteurs membranaires : du matériau à l'évaluation de l'intensification de l'absorption". Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0318/document.
Aqueous ammonia as a solvent for post-combustion CO2 capture in a packed column is seen as a promising technology. Nevertheless, ammonia volatility is a considerable drawback for its large scale deployment. In this study, the ability of hollow fiber membrane contactors to significantly improve CO2 mass transfer performances while mitigating ammonia losses when compared to packed column is evaluated. In that purpose, the use of innovating composite fibers made of a thin dense layer selective for CO2 over NH3 is proposed. Up to now, a faster permeation of CO2 compared to NH3 in dense polymers was totally unexpected and to our knowledge unexplored. Time-lag experiments have revealed a series of 6 fluorinated structures showing the desired reverse selectivity properties. Teflon AF2400 has been selected as the dense skin of composite fibers used during absorption experiments. Their performances have been compared, for different operating conditions, to those given by commercial microporous (Oxyphan) and composite (Oxyplus) membrane contactors. Due to ammonium salt precipitation issues, no stable experiment has been achieved using microporous membrane contactors. At the opposite, absorption efficiencies higher than post-combustion capture standards have been reached using composite membrane contactors. 2D mass transfer modeling has revealed the controlling role of the microporous support in the observed absorption performances. Finally, high CO2 mass transfer intensification factor and drastically reduced ammonia losses have been shown