Desde o início de 1980, quando o governo brasileiro decidiu reduzir os investimentos para a industrialização de óleo de xisto, os recursos existentes de xisto não tem feito parte da agenda da política energética nacional e pouca atenção tem sido dirigida à indústrialização do xisto no Brasil. Contudo, as discussões atuais sobre o pico de produção de petróleo no mundo e o aumento da demanda tem despertado a atenção dos gestores de recursos energéticos de vários países para os recursos de hidrocarbonetos nãoconvencionais, como os de óleo de xisto, ainda pouco explorado no mundo. Assim sendo, este estudo teve por objetivo geral a avaliação da viabilidade econômica do desenvolvimento dos recursos de óleo de xisto do sul do Brasil. Este estudo descreve os recursos de xisto no mundo e no Brasil, os custos operacionais, os custos de investimento e a tecnologia brasileira para retortagem de superfície para xisto. Para a avaliação da viabilidade econômica foram extrapoladas as estimativas dos custos de um projeto para explotação de xisto com capacidade de produção de 50.000 bbl por dia, do ano de 1980 para o ano de 2009, corrigindo-os apenas com a taxa de inflação em seguida foram feitas simulações de Monte Carlo para determinar o valor presente líquido (VPL), taxa de retorno (TIR) e período de retorno para vários cenários. Os resultados, considerando as condições de contorno descritas na metodologia, mostram como resultado mais importante, que os projetos de xisto apresentam viabilidade econômica e riscos aceitáveis quando o preço do barril do petróleo é maior que US$ 60,00 e pneus inservíveis são pirolisados juntamente com o xisto. Outros cenários podem ser viáveis, porém os riscos envolvidos foram considerados elevados. Contudo, quando analisados os resultados obtidos com as perspectivas do pré sal, o resultado desta análise nos induz a concluir que, para o Brasil, o xisto não se coloca como a melhor alternativa energética e, portanto, não deve ser criada a industria do xisto no Brasil. / Since the early 1980s, when the Brazilian government has decided to reduce investments for oil shale industrialization, the oil shale resources had not been part of national energy policy agenda and little attention has been given to the oil shale industry in Brazil. However, the current discussions about the peak oil production in the world combined with the increasing demand drawing attention to the unconventional hydrocarbon resources like oil shale, which is poorly explored in the world at present so this study presents an evaluating of economic feasibility of developing oil shale resources in the south of Brazil. It describes the oil shale resources in the world and in Brazil, operational costs, capital costs and Brazilian oil shale technology. For the evaluation of economic viability, was estimated the costs for a oil shale production project with capacity of 50.000 bbl per day and the Monte Carlo simulations was used to determine risks for some scenes. For the evaluation of economic viability was used the net present value (VPL), rate of return (TIR) and payback as parameters for evaluation The results, considering the methodology, show as more important result that the oil shale projects have economic feseability and acceptable risks when the oil price are higher than US$ 60,00 and the tires are process together oil shale. Other scenarios may be feasible, but the risks were considered high. However, when analyzing the results whit the pre-salt perspectives, the result of this analysis induce us to conclude that, for Brazil, oil shale does not the best alternative to energy and therefore should not be created the oil shale industry in Brazil.

La prévention des effets biologiques radio-induits en radiologie interventionnelle nécessite une estimation complète de l’exposition à la peau et aux organes du patient. Dans ce contexte, un logiciel permettant une reconstruction post-opératoire précise et rapide de la dosimétrie du patient par méthode Monte Carlo, a été développé. L’utilisation de techniques de réduction de variance et de navigation voxélisée avancées permet une amélioration significative du temps de calcul. Des fantômes anthropomorphes de dernière génération, couplés à la lecture des paramètres d’irradiation, permettent une prise en compte réaliste de l’anatomie du patient et de la géométrie de la machine. La précision de la modélisation Monte Carlo associée à un temps d’exécution réduit ainsi qu’à une complète automatisation rend cet outil particulièrement adapté à un calcul systématique en radiologie interventionnelle. / The prevention of the radio-induced biological effects in interventional radiology require a complete estimation of the patient skin and organs exposition. In this context, a software allowing a precise and fast postoperative reconstruction of the patient’s dosimetry using the Monte Carlo method was developed. The use of advanced methods of variance reduction and voxelized navigation allows a significant improvement in computing time. Last generation anthropomorphic phantoms, coupled with the reading of the irradiation parameters, allow to take realistic account of the patient's anatomy and the geometry of the machine. The precision of the Monte Carlo modelization associated with a reduced execution time as well as a complete automation makes this tool particularly suitable for a systematic calculation in interventional radiology.

This thesis participates to the effort launched after the Fukushima-Daiichi disaster to improve the robustness of national institutions involved in nuclear safety because of the role that the failing nuclear regulator had in the accident. The driving idea is to investigate how engineering techniques used in high-risk industries can be applied to institutions involved in nuclear safety to improve their robustness. The thesis focuses specifically on the Office for Nuclear Regulation (ONR), the British nuclear regulator, and its process for structured inspections. The first part of the thesis demonstrates that the hazard and operability (HAZOP) technique, used in the nuclear industry to identify hazards associated with an activity, can be adapted to qualitatively assess the robustness of organisational processes. The HAZOP method was applied to the ONR inspection process and led to the identification of five significant failures or errors. These are: failure to focus on an area/topic deserving regulatory attention; failure to evaluate an area/topic of interest; failure to identify a non-compliance; failure to identify the underlying issue, its full extent and/or safety significance and failure to adequately share inspection findings. In addition, the study identified the main causal chains leading to each failure. The safeguards of the process, i.e. the mechanisms in place to prevent, detect, resolve and mitigate possible failures, were then analysed to assess the robustness of the inspection process. The principal safeguard found is the superintending inspector who performs reviews of inspection reports and debriefs inspectors after inspections. It was concluded that the inspection process is robust provided recruitment and training excellence. However, given the predominant role of the superintending inspector, the robustness of the process could be improved by increasing the diversity of safeguards. Finally, suggestions for improvement were made such as establishing a formal handover procedure between former and new site inspectors, formalising and generalising the shadowing scheme between inspectors and setting minimum standards for inspection debriefs. These results were shared with ONR, which had reached the same conclusions independently, thus validating the new application for the HAZOP method. The second part of the thesis demonstrates that computational modelling techniques can be used to build digital twins of institutions involved in safety which can then be used to assess their effectiveness. The knowledge learned thanks to the HAZOP study was used in association with computational modelling techniques to build a digital twin of the ONR and its structural inspection process along with a simple model of a nuclear plant. The model was validated using the face-validity and predictive validation processes. They respectively involved an experienced ONR inspector checking the validity of the model’s procedures and decision-making processes and comparing the model’s output for oversight work done to data provided by the ONR. The effectiveness of the ONR was then evaluated using a scenario where a hypothetical, newly discovered phenomenon threatens the integrity of the plant, with ONR inspectors gradually learning and sharing new information about it. Monte-Carlo simulation was used to estimate the cost of regulatory oversight and the probability that the ONR model detects and resolves the issue introduced before it causes an accident. Different arrangements were tested and in particular with a superintending inspector reviewing inspection reports and a formal information sharing process. For this scenario, these two improvements were found to have a similar impact on the success probability. However, the former achieves it for only half the cost.

Ce travail de thèse a pour but de proposer des potentiels d'interaction et des méthodologies pour prédire, au travers de simulations Monte Carlo, les équilibres et propriétés de phases de systèmes oxygénés rencontrés dans les procédés de conversion de la biomasse. Le potentiel AUA4 a ainsi été étendu aux alcools, éthers, cétones, aldéhydes et esters carboxyliques. Une attention particulière a été portée à la transférabilité de ce champ de forces, afin de pouvoir simuler de manière prédictive un grand nombre de molécules oxygénées. Différentes propriétés d'équilibre de corps purs sont correctement prédites (masses volumiques, pressions de saturation, enthalpies de vaporisation, propriétés critiques, tensions de surface, structure de la phase liquide). De nombreux mélanges ont également été simulés dans le pseudo-ensemble point de bulle, qui a été étendu aux molécules polaires dans le cadre de ce travail. Les résultats de simulation de mélanges complexes comme des bioessences ont été validés par l'acquisition de nouvelles mesures expérimentales. Enfin, une nouvelle méthodologie pour le calcul des interactions électrostatiques intramoléculaires a été mise au point dans ce travail pour la simulation de molécules oxygénées multifonctionnelles (polyols, éthers de glycol, composés aromatiques oxygénés). L'utilisation de cette méthode, qui permet d'éviter l'emploi de paramètres empiriques additionnels, conduit à des résultats très encourageants, ce qui laisse entrevoir de nombreuses perspectives pour la prédiction de propriétés de mélanges industriels complexes. / The goal of this thesis work is to propose interaction potentials and numerical methods to predict through Monte Carlo simulations the phase equilibrium and properties of oxygenated systems involved in biomass conversion processes. The AUA4 potential was therefore extended to alcohols, ethers, ketones, aldehydes and carboxylic esters. A special care was paid to the transferability of this force field to allow the predictive simulation of a large number of oxygenated compounds. Various equilibrium properties of pure compounds are correctly predicted (densities, saturation pressures, vaporization enthalpies, critical properties, surface tensions, liquid phase structure). Many mixtures have also been simulated in the bubble point pseudo-ensemble which was extended in this work to polar molecules. The simulation results of complex mixtures such as biofuels have been validated through new experimental data acquisition. Finally, a new methodology for the intramolecular electrostatic energy interaction has been developed in this work to simulate multifunctional oxygenated molecules (polyols, glycol ethers, oxygenated aromatic compounds). The use of this method, which allows to avoid the use of additional empirical parameters, leads to promising results, giving thus future opportunities to predict properties of complex mixtures of industrial interest

Desde o início de 1980, quando o governo brasileiro decidiu reduzir os investimentos para a industrialização de óleo de xisto, os recursos existentes de xisto não tem feito parte da agenda da política energética nacional e pouca atenção tem sido dirigida à indústrialização do xisto no Brasil. Contudo, as discussões atuais sobre o pico de produção de petróleo no mundo e o aumento da demanda tem despertado a atenção dos gestores de recursos energéticos de vários países para os recursos de hidrocarbonetos nãoconvencionais, como os de óleo de xisto, ainda pouco explorado no mundo. Assim sendo, este estudo teve por objetivo geral a avaliação da viabilidade econômica do desenvolvimento dos recursos de óleo de xisto do sul do Brasil. Este estudo descreve os recursos de xisto no mundo e no Brasil, os custos operacionais, os custos de investimento e a tecnologia brasileira para retortagem de superfície para xisto. Para a avaliação da viabilidade econômica foram extrapoladas as estimativas dos custos de um projeto para explotação de xisto com capacidade de produção de 50.000 bbl por dia, do ano de 1980 para o ano de 2009, corrigindo-os apenas com a taxa de inflação em seguida foram feitas simulações de Monte Carlo para determinar o valor presente líquido (VPL), taxa de retorno (TIR) e período de retorno para vários cenários. Os resultados, considerando as condições de contorno descritas na metodologia, mostram como resultado mais importante, que os projetos de xisto apresentam viabilidade econômica e riscos aceitáveis quando o preço do barril do petróleo é maior que US$ 60,00 e pneus inservíveis são pirolisados juntamente com o xisto. Outros cenários podem ser viáveis, porém os riscos envolvidos foram considerados elevados. Contudo, quando analisados os resultados obtidos com as perspectivas do pré sal, o resultado desta análise nos induz a concluir que, para o Brasil, o xisto não se coloca como a melhor alternativa energética e, portanto, não deve ser criada a industria do xisto no Brasil. / Since the early 1980s, when the Brazilian government has decided to reduce investments for oil shale industrialization, the oil shale resources had not been part of national energy policy agenda and little attention has been given to the oil shale industry in Brazil. However, the current discussions about the peak oil production in the world combined with the increasing demand drawing attention to the unconventional hydrocarbon resources like oil shale, which is poorly explored in the world at present so this study presents an evaluating of economic feasibility of developing oil shale resources in the south of Brazil. It describes the oil shale resources in the world and in Brazil, operational costs, capital costs and Brazilian oil shale technology. For the evaluation of economic viability, was estimated the costs for a oil shale production project with capacity of 50.000 bbl per day and the Monte Carlo simulations was used to determine risks for some scenes. For the evaluation of economic viability was used the net present value (VPL), rate of return (TIR) and payback as parameters for evaluation The results, considering the methodology, show as more important result that the oil shale projects have economic feseability and acceptable risks when the oil price are higher than US$ 60,00 and the tires are process together oil shale. Other scenarios may be feasible, but the risks were considered high. However, when analyzing the results whit the pre-salt perspectives, the result of this analysis induce us to conclude that, for Brazil, oil shale does not the best alternative to energy and therefore should not be created the oil shale industry in Brazil.

Ce travail de thèse a pour but d'améliorer la précision de mesure de la dosimétrie basée sur le transducteur en Nitrure de Gallium (GaN) et de développer son application en radiothérapie. L'étude comprend des phases de modélisation, de simulation et de caractérisation de cette réponse pour la radiothérapie externe et la curiethérapie. En modélisation, nous avons proposé deux approches pour modéliser la réponse du transducteur GaN en radiothérapie externe. Dans la première approche, un modèle a été construit à partir de données expérimentales et en séparant les composantes primaires et diffusées du faisceau. Pour la deuxième approche, nous avons adapté un modèle initialement proposé pour les diodes silicium pour l'adapter au transducteur radioluminescent GaN. Nous avons également proposé un concept original de dosimétrie bi-média qui permet à partir des réponses mesurées des deux média de remonter à la dose dans les tissus, sans connaissance à priori des conditions d'irradiation. Ce concept a été démontré par des simulations Monte Carlo. Par ailleurs GaN pour la curiethérapie à Haut Débit de Dose, la réponse du transducteur GaN sous irradiation des sources d'iridium 192 et de cobalt 60 a été évaluée par simulation Monte Carlo et confirmée par des mesures. Des études de caractérisation des propriétés du transducteur radioluminescent GaN ont été réalisées avec ces sources. Un prototype de fantôme instrumenté avec des sondes GaN a été développé pour le contrôle qualité en curiethérapie HDR. Il permet de vérifier en temps réel les paramètres physiques du traitement (position de la source, le temps d'exposition, activité de la source) / The work in this thesis has the objective to increase the measurement precision of the dosimetry based on the Gallium Nitride (GaN) transducer and develop its applications on radiotherapy. The study includes the aspects of modeling, simulation and characterization of this response in external radiotherapy and brachytherapy. In modeling, we have proposed two approaches to model the GaN transducer’s response in external radiotherapy. For the first approach, a model has been built based on experimental data, while separating the primary and scattering component of the beam. For the second approach, we have adopted a response model initially developed for the silicon diodes for the GaN radioluminescent transducer. We have also proposed an original concept of bi-media dosimetry which evaluates the dose in tissue according to different responses from two media without prior information on the conditions of irradiation. This concept has been shown by Monte Carlo simulation. Moreover, for High Dose Rate brachytherapy, the response of GaN transducer irradiated by iridium 192 and cobalt 60 sources has been evaluated by Monte Carlo simulation and confirmed by the measurements. Studies on the property characterization of GaN radioluminescent transducer has been carried out with these sources as well. An instrumented phantom prototype with GaN probe has been developed for the HDR brachytherapy quality control. It allows a real-time verification of the physics parameters of a treatment (source dwell position, source dwell time, source activity)

This thesis deals with the direct simulation Monte Carlo (DSMC) method of analysing gas flows. The DSMC method was initially proposed as a method for predicting rarefied flows where the Navier-Stokes equations are inaccurate. It has now been extended to near continuum flows. The method models gas flows using simulation molecules which represent a large number of real molecules in a probabilistic simulation to solve the Boltzmann equation. Molecules are moved through a simulation of physical space in a realistic manner that is directly coupled to physical time such that unsteady flow characteristics are modelled. Intermolecular collisions and moleculesurface collisions are calculated using probabilistic, phenomenological models. The fundamental assumption of the DSMC method is that the molecular movement and collision phases can be decoupled over time periods that are smaller than the mean collision time. Two obstacles to the wide spread use of the DSMC method as an engineering tool are in the areas of simulation configuration, which is the configuration of the simulation parameters to provide a valid solution, and the time required to obtain a solution. For complex problems, the simulation will need to be run multiple times, with the simulation configuration being modified between runs to provide an accurate solution for the previous run�s results, until the solution converges. This task is time consuming and requires the user to have a good understanding of the DSMC method. Furthermore, the computational resources required by a DSMC simulation increase rapidly as the simulation approaches the continuum regime. Similarly, the computational requirements of three-dimensional problems are generally two orders of magnitude more than two-dimensional problems. These large computational requirements significantly limit the range of problems that can be practically solved on an engineering workstation or desktop computer. The first major contribution of this thesis is in the development of a DSMC implementation that automatically adapts the simulation. Rather than modifying the simulation configuration between solution runs, this thesis presents the formulation of algorithms that allow the simulation configuration to be automatically adapted during a single run. These adaption algorithms adjust the three main parameters that effect the accuracy of a DSMC simulation, namely the solution grid, the time step and the simulation molecule number density. The second major contribution extends the parallelisation of the DSMC method. The implementation developed in this thesis combines the capability to use a cluster of computers to increase the maximum size of problem that can be solved while simultaneously allowing excess computational resources to decrease the total solution time. Results are presented to verify the accuracy of the underlying DSMC implementation, the utility of the solution adaption algorithms and the efficiency of the parallelisation implementation.

Les efforts fournis par les exploitants du réseau électrique ont permis d'atteindre, aujourd'hui, un très bon niveau de fiabilité du réseau de transport et une disponibilité des réseaux de distribution tout à fait convenable. Néanmoins, considérant les modifications induites par les connexions de petits producteurs indépendants aux réseaux de distribution, les exploitants expriment un besoin d'évaluer la sûreté de fonctionnement de ces nouveaux réseaux. Les réseaux électriques présentent plusieurs particularités fonctionnelles, mises en évidence par l'étude qualitative des défaillances, comme les charges dispersées à plusieurs endroits du réseau, la topologie variable du réseau et certains phénomènes électrotechniques qui doivent être pris en compte pour modéliser les événements que peut subir le système. La méthode de calculs de sûreté retenue est la simulation Monte Carlo, méthode probabiliste la plus performante et la plus souple d'utilisation au regard de la complexité des réseaux étudiés. Nous avons consacré une première partie des travaux sur le cas d'un départ HTA auquel est connecté une centrale de cogénération. La méthode a été appliquée sur un logiciel de simulation de réseaux de Petri stochastiques. Puis une deuxième partie a concerné l'étude d'un réseau BT alimenté uniquement par des générations dispersées. Ici, la complexité des événements a nécessité de coder et de développer la méthode dans un environnement de programmation permettant l'intégration de modules de calculs de réseaux (répartition de charges, courts-circuits, délestage, gestion des puissances produites,...) afin de pouvoir diagnostiquer l'état du système durant les événements simulés.

Ce sujet de thèse concerne le développement et la mise au point d'un système de dosimétrie passive à base des détecteurs BaFBr:Eu2+ répondant aux nouvelles recommandations de la CIPR. Lorsqu'un film photostimulable est exposé aux rayonnements ionisants, il convertit l'énergie absorbée en une image latente. Cette énergie, emmagasinée par des électrons piégés, peut être ensuite libérée en différé sous l'effet d'une stimulation LASER sélective. Cette dernière provoque une luminescence proportionnelle à la dose reçue. Des mesures expérimentales de la fonction de réponse, en dose et en énergie, des neutrons et des rayonnements Γ ont été réalisées et complétées par des calculs de modélisation Monte-Carlo. Il ressort de cette étude que ce système peut être adapté à la dosimétrie passive des faibles et des fortes doses. Les résultats montrent un seuil de détection en équivalent de dose de 23 µSv pour les neutrons rapides et de 1,5 µGy pour les rayonnements Γ d'énergie 1,2 MeV. Destinés à la dosimétrie passive personnelle, les dosimètres mis au point ont été irradiés en conditions réelles d'utilisation, sous faisceaux de neutrons rapides et thermiques, à différents angles sur un fantôme selon les normes ISO. Ces études ont également montré la possibilité d'utiliser pour la première fois ces films pour d'autres applications en dosimétrie, notamment pour la détection du signal radon dans l'environnement. Malgré leurs avantages (facilité d'utilisation, rapidité de lecture, numérisation de l'image, remise à zéro, absence de traitement chimique) par rapport aux d'autres détecteurs passifs tels que les solides de traces nucléaires ou les thermoluminescents, les photostimulables présentent un inconvénient lié au fading. Nous présentons deux procédures pour la correction de ce fading pendant et après irradiation.

Ce travail vise à démontrer la faisabilité d'un dosimètre opérationnel neutrons basé sur la technologie CMOS. Le capteur utilisé (MIMOSA-5) doit pour cela être transparent aux γ et pouvoir détecter les neutrons sur une large gamme d'énergie en gardant évidemment une bonne efficacité de détection. La réponse du système de détection, constitué du capteur CMOS adjoint d'un matériau convertisseur (polyéthylène pour les neutrons rapides, 10B pour les neutrons thermiques), a été confrontée à des si-mulations Monte Carlo effectuées avec MCNPX et GEANT4. Un travail de validation de ces codes a préalablement été effectué pour justifier leur utilisation dans le cadre de notre application. Les expériences nous permettant de caractériser le capteur ont été menées au sein de l'IPHC ainsi qu'à l'IRSN/LMDN (Cadarache). Les résultats de l'exposition du capteur à des sources de photon pures et à un champ mixte n/γ (source 241AmBe) montrent la possibilité d'obtenir un système transparent aux γ par application d'une coupure appropriée sur le dépôt d'énergie (aux alentours de 100 keV). L'efficacité de détection associée est très satisfaisante avec une valeur de 10-3, en très bon accord avec MCNPX et GEANT4. La réponse angulaire du capteur a été étudiée par la suite à l'aide de la même source. La dernière partie de cette étude traite de la détection des neutrons thermiques (de l'ordre de l'eV). Les expériences ont été menées à l'IRSN sur une source de 252Cf modérée à l'eau lourde. Les résultats ob-tenus ont montré une très bonne efficacité de détection (allant jusqu'à 6×10-3 pour un convertisseur do-pé au 10B) en très bon accord avec GEANT4.