Made available in DSpace on 2014-12-17T14:07:06Z (GMT). No. of bitstreams: 1 RayssaRNMS_DISSERT.pdf: 4171010 bytes, checksum: 0d447597643468751a7d9a8d1824c61d (MD5) Previous issue date: 2012-08-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The field of "Materials Chemistry" has been developing in recent years and there has been a great increase of interest in the synthesis and chemical and physical properties of new inorganic solids. New routes of synthesis and synthesis modified has been developed with the aim not only to optimize the processes in laboratory scale, but also on an industrial scale, and make them acceptable by current environmental legislation. The phenomenology of current solid state chemistry properties coupled with the high temperature superconductivity, ferromagnetism, porosity molecular and colors are evidence affected by the synthesis method, which in turn can influence the technological application of these materials. From this understanding, mixed oxides of nickel and zinc nanoparticulate were synthesized by microwave-assisted combustion route using three specific types of organic fuels employing the weight ratios 1:1/2 and 1:1 of cation metallic/fuel, in order to investigate the influence of such proportions to obtain the solids. The new fuels were chosen to replace, for example, urea or glycine that are the fuels most commonly preferred in this kind of synthesis. The powders without heat treatment were studied by Thermogravimetric analysis (TGA), X-Ray Diffraction (XRD) and then calcined at 900?C. After heat treatment, the samples were characterized by analysis of X Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The modified synthesis route porposed was effective for obtaining powders. Both the alternative fuels chosen as the different weight ratios employed, influenced in the morphology and obtaining oxides / O campo da Qu?mica de Materiais vem se desenvolvendo nos ?ltimos anos, tendo havido um grande aumento do interesse na s?ntese e nas propriedades qu?micas e f?sicas de novos s?lidos inorg?nicos. Novas rotas de s?nteses e s?nteses modificadas tem sido desenvolvidas com o intuito n?o apenas de otimizar os processos em escala laboratorial, como tamb?m em escala industrial, al?m de torn?-los aceit?veis pela legisla??o ambiental vigente. A atual fenomelogia da qu?mica do estado s?lido aliada ?s propriedades de supercondutividade ? alta temperatura, ferromagnetismo, porosidade molecular e cores s?o evid?ncias afetadas pelo m?todo de s?ntese, que por sua vez, podem influenciar na aplica??o tecnol?gica desses materiais. Foi a partir desta compreens?o, que ?xidos mistos de n?quel e zinco nanoparticulados foram sintetizados atrav?s da rota combust?o por microondas utilizando tr?s tipos espec?ficos de combust?veis e empregando as raz?es m?ssicas 1:1 e 1:1/2 de c?tions met?licos/combust?vel, com o intuito de averiguar a influ?ncia de tais propor??es na obten??o dos s?lidos. Os novos combust?veis foram escolhidos em substitui??o a ur?ia ou glicina que s?o mais comumente preferidos nesse tipo de s?ntese. Os p?s sem tratamento t?rmico foram estudados atrav?s da An?lise Termogravim?trica (ATG) e da Difra??o de Raios-X (DRX), sendo, em seguida, submetidos ao tratamento t?rmico ? 900?C. Ap?s as calcina??es, foram caracterizados atrav?s das an?lises Difra??o de raiosx (DRX) e Microscopia Eletr?nica de Varredura (MEV). A rota de s?ntese modificada foi eficaz para obten??o dos p?s. Tanto os combust?veis alternativos escolhidos quanto as diferentes raz?es m?ssicas empregadas, influenciaram na morfologia e na obten??o dos ?xidos

Made available in DSpace on 2014-10-09T12:41:34Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:02Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Les futurs réacteurs à neutrons rapides refroidis au sodium (RNR-Na) doivent remplir les critères GEN-IV à savoir présenter des qualités d'économie, de sûreté améliorée, de résistance à la prolifération et de minimisation des déchets. Ce projet de thèse est dédié à l'étude de l'impact des combustibles innovants (spécialement le combustible oxyde sphere-pac chargé en actinides mineurs) sur les performances de sûreté des RNR-Na dédiés à la transmutation.Le code de calcul SIMMER-III, développé à l'origine pour les phases avancées d'un accident grave, est utilisé pour les simulations. Ce code a été étendu dans le cadre de cette thèse afin d'améliorer la simulation de la phase primaire de l'accident, en introduisant le traitement des effets en réactivité liés à la dilatation du cœur et les spécificités du combustible sphere-pac (conductivité thermique, gap). Les transitoires complets (de la phase d'initiation aux phases avancées) sont simulés avec cette version étendue du code. Dans le cadre de cette thèse, les propriétés thermiques du combustible sphere-pac ont été modélisées et adaptées à SIMMER. Une méthodologie innovante tenant compte des effets en réactivité liés à la dilation thermique du cœur dans un maillage Eulérien et dans le cadre de la cinétique spatiale a ensuite été développée. A chaque pas de temps, les dimensions et densités dilatées sont calculées pour chaque cellule suite aux variations de températures. Des facteurs correctifs sont appliqués aux densités dilatées pour obtenir une configuration équivalente (en réactivité) ayant les dimensions non-dilatées et des densités modifiées. De nouvelles sections efficaces sont calculées à partir de ces densités et l'effet en réactivité lié à la dilatation est calculé. Les résultats sont prometteurs pour des dilatations uniformes et non-uniformes. Des limitations dans le cas de dilatations non-uniformes ont été identifiées et des calculs neutroniques ont été effectués en vue de futurs développements SIMMER. Les résultats préliminaires sont encourageants. Enfin, deux cœurs RNR-Na, issus du précédent projet CP-ESFR, ont été modélisés avec des combustibles sphere-pac : le Working Horse et le CONF2 (présentant un plénum sodium élargi pour une diminution de l'effet de vide sodium). Des analyses de sûreté ont été effectuées afin de fournir une première évaluation du comportement du combustible sphere-pac comparé au combustible pastille. Les deux options sont analysées en situation nominale et accidentelle (accident de perte de débit primaire) en début de vie du cœur et après irradiation. Les analyses révèlent deux phases à considérer en début de vie pour le combustible sphere-pac. Au démarrage du réacteur, ce combustible n'est pas restructuré et sa conductivité thermique est très inférieure à celle du combustible pastille. Après quelques heures sous irradiation, il se restructure suite aux importants gradients de température, ce qui améliore sa conductivité. Il se comporte alors de façon similaire au combustible pastille. Ce travail a également permis d'évaluer le comportement accidentel du cœur CONF2 qui subit un transitoire doux, prouvant que le large plénum sodium prévient efficacement de larges insertions de réactivité positive. Cependant, avec l'ajout d'américium ou suite à l'irradiation, des excursions de puissance et de réactivité plus prononcées sont observées. Ce travail a permis de démontrer que le combustible sphere-pac ne semble pas causer de problèmes de sûreté spécifiques comparé au combustible pastille, dans les conditions de simulations actuelles. La prise en compte des effets en réactivité liés à la dilatation du cœur avec cette version étendue de SIMMER retarde et réduit le potentiel énergétique lors d'un accident. Les analyses confirment également l'action atténuante du plénum sodium sur les transitoires conduisant à la vidange du sodium du coeur. Le comportement du combustible sphere-pac dans ces conditions ouvre une perspective à son utilisation en RNR-Na. / Future sodium cooled fast reactors (SFRs) have to fulfill the GEN-IV requirements of enhanced safety, minimal waste production, increased proliferation resistance and high economical potential. This PhD project is dedicated to the evaluation of the impact of innovative fuels (especially minor actinides bearing oxide sphere-pac fuels) on the safety performance of advanced SFRs with transmutation option. The SIMMER-III code, originally tailored to mechanistically analyze later phases of core disruptive accidents, is employed for accident simulations. During the PhD project, the code has been extended for a better simulation of the early accident phase introducing the treatment of thermal expansion reactivity effects and for taking into account the specifics of sphere-pac fuels (thermal conductivity and gap conditions). The entire transients (from the initiating event to later accident phases) have been modeled with this extended SIMMER version. Within this PhD work, first the thermo-physical properties of sphere-pac fuel have been modeled and casted into SIMMER-III. Then, a new computational method to account for thermal expansion feedbacks has been developed to improve the initiation phase modeling of the code. The technique has the potential to evaluate these reactivity feedbacks for a fixed Eulerian mesh and in a spatial kinetics framework. At each time step, cell-wise expanded dimensions and densities are calculated based on temperature variations. Density factors are applied to the expanded densities to get an equivalent configuration (in reactivity) with original dimensions and modified densities. New cross sections are calculated with these densities and the reactivity of the equivalent configuration is computed. The developed methods show promising results for uniform and non-uniform expansions. For non-uniform expansions, model improvement needs have been identified and neutronics simulations have been carried out to support future SIMMER extensions. Preliminary results are encouraging. In the third part of the PhD, two core designs with conventional and sphere pac fuels are compared with respect to their transient behavior. These designs were established in the former CP-ESFR project: the working horse core and the optimized CONF2 core (with a large sodium plenum above the core for coolant void worth reduction). The two fuel design options are compared for steady state and transient conditions (Unprotected Loss of Flow accident, ULOF) either at beginning of life (BOL) or under irradiated conditions. Analyses for sphere-pac fuel reveal two main phases to consider at BOL. At start-up, the non-restructured sphere-pac fuel shows a low thermal conductivity compared to pellet fuel of same density. However, the fuel restructures quickly (in a few hours) due to the high thermal gradients and its thermal conductivity recovers. The fuel then shows a behavior close to the pellet one. The study also shows that the CONF2 core leads to a very mild transient for a ULOF accident at BOL. The large upper sodium plenum seems to effectively prevent large positive reactivity insertions. However, stronger reactivity and power peaks are observed under irradiated conditions or when americium is loaded in the core and lower axial blanket. This PhD work demonstrates, under current simulation conditions, that sphere-pac fuels do not seem to cause specific safety issues compared to standard pellet fuels, when loaded in SFRs. The accurate simulation of core thermal expansion reactivity feedbacks by means of the extended SIMMER version plays an important role in the accident timing (simulations confirm the expected delay in the first power peak) and on the energetic potential compared to the case where these feedbacks are omitted. The analyses also confirm the mitigating impact of a large sodium plenum on transients with voiding potential. The behavior of sphere-pac fuel in these conditions opens a perspective to its practical application in SFRs.

Ce travail de recherche vise à étudier les propriétés élastiques par microscopie acoustique du combustible nucléaire dans trois situations particulières: combustible en utilisation normale en réacteur nucléaire, combustible stocké après la période d’irradiation et combustible en conditions extrêmes suite à un accident nucléaire. Les mesures réalisées sur les échantillons irradiés ont conduit à plusieurs résultats majeurs: validation d’une loi corrélant la vitesse des ondes de Rayleigh à la densité du dioxyde d’uranium irradié ou frais; détermination de la porosité dans le combustible irradié; évaluation du gonflement de la matrice en fonction du taux de combustion dans la gamme 0-100 GWdt-1M; développement d'un modèle empirique capable de prévoir la variation de module de Young en fonction du taux de combustion en prenant même en compte la teneur en dopants (Gd2O3, CeO2) ; quantification de l’évolution du module de Young du combustible suite à l'endommagement en stockage ; premières mesures sur du corium. Enfin, grâce au lien entre les propriétés thermiques et élastiques, différentes propriétés thermiques de l'UO2 ont été calculées en mesurant la vitesse de l'onde de surface de Rayleigh seule. / The focus of the present thesis is the determination of the elastic properties of nuclear fuel using high frequency acoustic microscopy. The nuclear fuel is considered under three different conditions: during its normal life in reactor, after its discharge and disposal in interim or long-term storage and subsequently to its severe degradation caused by a nuclear accident. Measurements performed on irradiated fuels allowed to validate a law between the density of fresh and irradiated fuel and the Rayleigh wave velocity; the determination of the irradiated fuel porosity and matrix swelling in the broad burnup range 0-100 GWdt-1M; the development of an empirical model capable of predicting the evolution of Young's modulus versus burnup correcting also for the additives content (Gd2O3, CeO2); Young's modulus evolution due to alpha-decay damage as in-storage condition; first corium measurements. Moreover, several UO2 thermal parameters were calculated only by means of the Rayleigh wave velocity thanks to the link between thermal and elastic properties.

The author analyzes the Mexico’s energetic reform during the sexennial of 2013 to 2018. A historic study refers that Mexican energy matrix was based on fossil sources of energy as crude oil and natural gas. This represents nearly 90% of primary energy’s total production while the profit of non-fossil energy represents only 8% until 2012.Then, during the period of 2007-2012, the majority of the programmatic and normative instruments about climate change were generated. From 2013 to 2018, said the author, a national structural reform has been discussed. Thisamend includes Mexico’s energetic reform that proposes the «fossilization» of Mexican economy. This «fossilization» of the economy will favor the green growth and will constitutes itself as a barrier for Mexico’s fulfillment of international commitments assumed aboutclimate change, as well as its transition to a low carbon economy. / La autora analiza la reforma energética en México en el sexenio 2013 – 2018 a la luz de un análisis histórico sobre la matriz energética de dicho país, que al 2012 estaba basada en fuentes fósiles de energía: petróleo crudo y gas natural, que representaban conjuntamente cerca del 90% de la producción total de energía primaria; mientras que el aprovechamiento de energías no fósiles representaba solo el 8%. Asimismo, señala que en el periodo 2007- 2012 se generaron la mayoría de los instrumentos programáticos y normativos en materia de cambio climático, instrumentos que acompañaron la política internacional en la materia. En este sexenio 2013-2018, asevera la autora, se discute una reforma nacional estructural que incluye la reforma energética de México, que plantea la «fosilización» de la economía mexicana en aras de favorecer el crecimiento verde, que viene a constituirse en un obstáculo para que México pueda cumplir los compromisos internacionales asumidos en materia de cambio climático y transitar a una economía baja en carbono.

[pt] O transporte de petróleo e de seus derivados através do modal dutoviário é bastante comum na indústria petrolífera. O Oleoduto do Recôncavo-Sul da Bahia (ORSUB) é um poliduto que transporta diesel, gasolina e GLP do Terminal de Madre de Deus até os terminais de Jequié e Itabuna. Esses produtos são inseridos no poliduto em forma de bateladas sequênciais, o que gera as interfaces entre os produtos. Essas interfaces são segregadas e armazenadas em tanques exclusivos. A Agência Nacional de Petróleo ao longo do tempo vem restringindo cada vez mais as especificações dos produtos derivados do petróleo comercializados no país. Com isto, há a tendência natural do aumento das interfaces entre os produtos movimentados no poliduto, para a garantia de que estes atendam a legislação vigente. Estudos demonstram que os custos provenientes da geração de interfaces são altos e constituem um item importante na composição dos custos variáveis do modal dutoviário. Deste modo, reduzir o tamanho destas interfaces deve sempre ser um dos objetivos que o operador logístico responsável pela movimentação no duto deve buscar. Nesta pesquisa foram estudadas as interfaces geradas entre a gasolina e o GLP no ORSUB. Foi utilizado o software ConBate para a estimativa do tamanho da interface e o simulador de processos Petrox, para estimar a qualidade da interface. Com estas duas ferramentas desenvolvidas pelo Centro de Pesquisa da Petrobras (Cenpes) foram comparadas os tamanhos das interfaces geradas nas operações reais, com os tamanhos das interfaces ideais. / [en] The transportation of oil and its derivatives through modal pipeline is quite common in the oil industry. The pipeline Recôncavo-Sul Bahia (ORSUB) is an oil pipeline that transports gas oil, gasoline and LPG from Terminal Madre de Deus to the terminals Jequié and Itabuna. These products are inserted into the oil pipeline in the form of batches, which generates the interfaces (transmix) between products. These transmix are segregated and stored in dedicated tanks. Over time, The National Petroleum Agency (ANP) is increasingly restricting the specifications of petroleum products sold in the country. With this, there is the natural tendency of increased interfaces between the products moved in pipeline, to ensure that they meet current legislation. Studies show that the costs arising from the generation of interfaces are high and constitute an important item in the cost composition variables modal pipeline. Thus, reducing the size of these interfaces should always be a goal that the logistics operator responsible for moving the product should look. In this research we studied the interfaces generated between gasoline and LPG in ORSUB. ConBate software was used to estimate the size of the interface and process simulator Petrox to estimate the quality of transmix. With these two tools sizes of the interfaces generated in actual operations and the sizes of the interfaces ideal were compared.

Submitted by Marcio Emanuel Paixão Santos (marcio.santos@ucsal.br) on 2018-06-21T00:00:54Z No. of bitstreams: 1 DISSERTACAOMARCELOALMEIDASENHORINHO.pdf: 3543675 bytes, checksum: 6ec4b65652c6855733acac72c2e8a3be (MD5) / Approved for entry into archive by Linda Bulhosa (linda.gomes@ucsal.br) on 2018-06-21T19:18:40Z (GMT) No. of bitstreams: 1 DISSERTACAOMARCELOALMEIDASENHORINHO.pdf: 3543675 bytes, checksum: 6ec4b65652c6855733acac72c2e8a3be (MD5) / Made available in DSpace on 2018-06-21T19:18:40Z (GMT). No. of bitstreams: 1 DISSERTACAOMARCELOALMEIDASENHORINHO.pdf: 3543675 bytes, checksum: 6ec4b65652c6855733acac72c2e8a3be (MD5) Previous issue date: 2009-11-30 / O presente estudo trata das diversas interações existentes entre o Baixo Sul do Estado da Bahia, sua população, seus remanescentes de Mata Atlântica e os impactos advindos da expansão das áreas da cultura do dendê existentes, com vistas à produção de biodiesel. Esta expansão vem sendo estimulada, por Programas e Projetos, frutos de uma Política Pública de Governo, que se propõem a alterar a matriz energética vigente baseada em combustíveis fósseis não renováveis, por biocombustíveis mais limpos e renováveis, principalmente de origem agrícola. O Brasil sempre foi reconhecido por sua natural vocação agrícola, o que o coloca em uma posição estrategicamente importante nesta nova realidade que se afigura. São inegáveis as vantagens apresentadas pelos biocombustiveis, ainda mais em um ambiente cada dia mais afetado pelas mudanças climáticas e uma sociedade cada dia mais preocupada com o aquecimento global e as suas consequências. Não se sabe quando, mas as reservas mundiais de petróleo um dia se esgotarão e substitutos deverão ser viabilizados. Dentre as opções existentes, os biocombustiveis aparecem como uma das alternativas viáveis, mas o que pouco se discute são os impactos gerados por uma expansão indiscriminada das áreas de cultivo e os efeitos sobre as matas nativas, as outras culturas existentes, as populações e seu modo de vida. Pôde-se constatar que as políticas públicas de incentivo à produção de biodiesel constituem-se em um fator positivo de desenvolvimento regional, ainda mais em um país em desenvolvimento como o nosso, mas que salvaguardas devem ser adotadas buscando modelos que conciliem desenvolvimento socioeconômico com conservação ambiental. / The present study discusses several interactions among the “Baixo Sul” of the State of Bahia, its population, its Atlantic Forest remnants and the probable impacts resulting from the expansion of the areas of palm oil plantations, for biodiesel production. This expansion is stimulated by Government Programs and Projects that aim at the alteration of the energetic matrix in use, based on fuels fossils by a cleaner one based on renewable fuel, especially, coming from agriculture. Brazil was always recognized by his natural agricultural vocation, which puts it in a strategically important position in this new world order. The advantages presented by the biofuels are undeniable, even in an environment more affected by climate change and a society more preoccupied with global warming and its consequences each day. It is not known when, but fatally the world oil reserves one day will be exhausted one day and substitutes will have to be found. Among the existing options, the Biofuels appear like one of the viable options. But the impacts produced by an indiscriminate expansion of the areas of cultivation and the effects on the native forests, other existing cultures, the populations and its way of life are little discussed. Finally, the study tries to demonstrate that the public incentive policies for the production of biodiesel are a positive factor of regional development, even more in a needing country like ours, but that right options must be adopted looking for models that reconcile economic development with environmental conservation.

Made available in DSpace on 2014-10-09T12:50:18Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:58:53Z (GMT). No. of bitstreams: 1 10885.pdf: 6800168 bytes, checksum: 564283882a42941e0a49be623bd8981e (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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Made available in DSpace on 2014-10-09T12:41:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:38Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP