Made available in DSpace on 2014-10-09T12:33:48Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:26Z (GMT). No. of bitstreams: 0 / Com a necessidade de novas formas de produção de energia para conter a crise ambiental e o aquecimento global, novas tecnologias têm sido estudadas e a energia nuclear foi apontada como uma das saídas para a produção de energia limpa. O estudo do risco está diretamente relacionado ao estudo de sua percepção, que determina a maneira de agir do ser humano e, portanto influencia na aplicação de novas tecnologias, uma vez que o reconhecimento de algo como perigoso é determinado por fatores sócio históricos. Este estudo teve como objetivo comparar as percepções de risco nuclear e ambiental, em um grupo de estudantes universitários, com a aplicação de uma pesquisa, no período de 31 de março a 31 de maio de 2010, contendo: imagens de fatos históricos para serem nomeados; estruturação de uma escala de risco para determinadas atividades; e um questionário sobre riscos e benefícios relacionados ao tema da pesquisa. A análise dos resultados evidenciou uma diminuição da percepção do risco nuclear em relação ao risco ambiental na população estudada. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-12-10T16:50:28Z No. of bitstreams: 0 / Made available in DSpace on 2015-12-10T16:50:28Z (GMT). No. of bitstreams: 0 / Nesta tese enfocamos a energia nuclear para geração de energia elétrica no Brasil, com relação à sua contribuição para o desenvolvimento sustentável, utilizando como referencial a NBR ISO 26000: Diretrizes sobre Responsabilidade Social; abordamos os conceitos de desenvolvimento sustentável e responsabilidade social, princípios, temas e questões associadas à governança organizacional; direitos humanos; práticas no trabalho; meio ambiente; práticas leais de operação; consumidor e desenvolvimento e envolvimento comunitário. Determinamos a importância das questões utilizando um questionário na internet. Avaliamos os resultados utilizando as técnicas de modelagem por equações estruturais (PLS-SEM) partial least square. Discorremos sobre as perspectivas sobre energia no mundo e no Brasil e o papel da energia nuclear em um futuro de energia de baixo carbono e ressaltamos que a energia nuclear é sustentável, porque internaliza todos os custos das suas externalidades e não gera gases de efeito estufa e se constitui na única tecnologia, madura e disponível, para dar conta da demanda global de energia, que deve dobrar ou triplicar neste século. Abordamos o diálogo entre a organização, suas partes interessadas e a sociedade enfocando a opinião pública e a energia nuclear na geração de energia elétrica no Brasil, com recomendações sobre prática e integração da responsabilidade social e ações com partes interessadas. Discutimos as dificuldades de comunicar à sociedade e às partes interessadas as vantagens e benefícios da energia nuclear, rompendo barreiras e preconceitos arraigados na sociedade e as diferenças entre a responsabilidade social desejada, relatada e percebida. Algumas das questões importantes são abordadas em conjunto com as evidências de atendimento e oportunidades de melhorias em seu endereçamento. Esta tese pode ser utilizada para facilitar a aceitação da energia nuclear, principalmete: Subsidiando a formulação de políticas publicas; No aprimoramento da educação e temas de ensino e; Na definição de campanhas de conscientização da população. A metodologia desenvolvida pode ser usada no diálogo qualificado com as PARTES INTERESSADAS e com a sociedade, pois: Identifica as questões importantes; Comunica as evidências de atendimento e; Permite demonstrar a sustentabilidade da energia nuclear. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Orientador: Elias Basile Tambourgi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-09T16:29:04Z (GMT). No. of bitstreams: 1 Assis_Ginode_D.pdf: 24086510 bytes, checksum: b80c2dd3dcdda04486140dd86e3c5360 (MD5) Previous issue date: 2007 / Resumo: Neste trabalho é apresentado um estudo de crescimento de grãos em pastilhas de UO2, em sinterizações a 1700°C/2h/H2 e a 1750°C/4h/H2, por intermédio do crescimento das partículas do pó de UO2, do semeamento isoestrutural e da adição de Al2O3-SiO2. O crescimento das partículas do pó resultou em pastilhas com estruturas de grãos e poros grandes no centro e pequenos na borda, que foram atribuídas a diferentes pressões de oxigênio nestas duas regiões das pastilhas. A 1700°C/2h/H2 o tamanho médio de grãos foi de 8,73 µm, que aumentou para 34,16 µm após ser novamente sinterizada a 1750°C/4h/H2. Após estocagem do pó por um ano, novas pastilhas obtidas a 1700°C/2h/H2 e a 1750°C/4h/H2 apresentaram tamanho médio de grãos de 3,51 e 20,50 µm. O menor crescimento de grãos nas pastilhas obtidas do pó estocado foi atribuído à maior energia de superfície deste pó devido a oxidação superficial das suas partículas durante o período de estocagem. Na aplicação da técnica do semeamento isoestrutural foram testadas sementes obtidas de pó de UO2 sinterizado, nos teores 1, 3 e 5% em peso, e tamanhos 0-5, 5-10, 10-20 e 20-38 µm. O tamanho da semente exerceu muito pouca influência sobre a densificação e o crescimento de grãos. Após sinterização a 1700°C/2h/H2 o tamanho médio de grãos aumentou com a adição de 1% de sementes enquanto a densidade permaneceu constante; no entanto, tanto a densidade quanto o tamanho de grãos diminuíram com adições acima de 1% em peso. Após sinterização a 1750°C/4h/H2, a densidade aumentou para todos os teores de sementes, no entanto, o tamanho médio de grãos aumentou com a adição de 1% de sementes e caiu para os demais teores. A adição de Al2O3-SiO2 foi experimentada com 0,1 e 0,2% em peso. Em todos os experimentos foram obtidas microestruturas de grãos homogêneas, o que sugere ter havido mudança das interfaces do sistema de sólido-gás para líquido-gás, anulando a influência da pressão de oxigênio sobre o crescimento de grãos, ou seja, houve sinterização em presença de fase líquida. Em ambas as condições de sinterização o teor de 0,1% em peso de Al2O3-SiO2 aumentou a capacidade de densificação das pastilhas, a qual diminuiu com a adição de 0,2% em peso. A 1700°C/2h/H2 houve aumento do tamanho médio de grãos com o aumento do teor desses aditivos. A 1750°C/4h/H2 o tamanho médio de grãos foi praticamente o mesmo na pastilha sem aditivos e na pastilha com adição de 0,2% em peso de Al2O3-SiO2, porém, o tamanho médio de grãos diminuiu com a adição de 0,1% em peso de Al2O3-SiO2. Os resultados obtidos permitiram analisar os mecanismos envolvidos na densificação e evolução das microestruturas de grãos e poros, nas diferentes condições de processamento testadas. Além de mostrar caminhos possíveis de crescimento de grãos em pastilhas de UO2, estes resultados poderão ser utilizados no desenvolvimento de pastilhas combustíveis com microestruturas adequadas para obtenção de combustível de alto desempenho para reatores nucleares de potência / Abstract: In this work, a study on UO2 pellets grain growth is presented, by sintering at 1700°C/2h/H2 and 1750°C/4h/H2, by coarsening the UO2 powder particles, by isostructural seeding and by Al2O3-SiO2 additions. The coarsening of the powder particles resulted in pellets with large grains and pores in the center and small ones close to the rim, which were attributed to different oxigen pressures in these two zones of the pellets. After sintering at 1700°C/2h/H2, the pellet average grain size attained 8.73 µm, which increased to 34.16 µm after another sintering at 1750°C/4h/H2. After being stored the powder for one year, new pellets were obtained at 1700°C/2h/H2 and at 1750°C/4h/H2, and their average grain size attained 3.51 and 20.50 µm, respectively. The minor grain growth in the pellets obtained from stored powder was attributed to the major surface energy of this powder, due to their particles surface oxidation during the storage period. Using the isostructural seeding technical, seeds obtained from UO2 powder sintering were used, on 1, 3 and 5 wt%, and within the band sizes 0-5, 5-10, 10-20 and 20-38 µm. The seed size caused too little influence on densification and grain growth. After sintering at 1700°C/2h/H2, the average grain size increased with 1 wt% seed addition, while the density remained constant; therefore, both density and average grain size decreased when the seed addition was over 1 wt%. After sintering at 1750°C/4h/H2, the density increased due to all seed grades, therefore, the average grain size increased due to 1 wt% seed addition but dropped to the other major grades. Al2O3-SiO2 additions were tested on 0.1 and 0.2 wt%. Homogeneous grain microstructures were obtained in all experiments, suggesting the change from the solid-gas interface to liquid-gas interface, avoiding the oxigen pressure influence on grain growth, i.e., there was sintering in liquid phase. The pellets densification ability was increased in both sintering conditions, when 0.1 wt% Al2O3-SiO2 was added; however, this ability decreased when 0.2 wt% Al2O3-SiO2 was added. At 1700°C/2h/H2, the average grain size increased in both Al2O3-SiO2 grades used. At 1750°C/4h/H2, the average grain size was approximately the same value in the pellet without additions and in the pellet with 0.2 wt% Al2O3-SiO2, but it decreased in the pellet with 0.1 wt% Al2O3-SiO2. These results allowed to analyse the mechanisms envolved on densification and, grains and pores microstructure evolution, on the different sintering conditions tested. They showed grain growth possibilities in UO2 pellets, which may be used in fuel pellets technology development with suitable microstructure, for obtaining of high performance fuel for nuclear power reactors / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

Orientador: Elias Basile Tambourgi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-20T02:06:50Z (GMT). No. of bitstreams: 1 Pinto_AmenoniaMariaFerreira_D.pdf: 8928817 bytes, checksum: adae0f7cc1ba62c41e7595bc4dd74788 (MD5) Previous issue date: 2012 / Resumo: A metodologia desenvolvida estabelece alternativas que possibilitam a quantificação do óleo estacionado no volume poroso dos reservatórios de petróleo. Foi admitido que, o conhecimento do coeficiente de partição do radônio entre o óleo e a água presentes no reservatório, viabilizará a determinação da Saturação Residual, levando-se em conta o aumento da quantidade de radônio na fase aquosa em relação à quantidade presente antes de ser iniciada a recuperação secundária, quando o óleo é expulso pela injeção de água. Foram executados testes, em escala de laboratório, em um corpo de prova composto por um meio poroso construído de forma a simular as características de um reservatório. O corpo de prova, elaborado a partir de uma rocha sedimentar de minério de urânio, foi acondicionado em um coreholder onde foram reproduzidas as etapas desde a formação até o esgotamento de um reservatório...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: A method has been developed for the quantification of the amount of petroleum remaining within the porous volume of oil reservoirs using radon as a natural tracer. The Oil Saturation is estimated, taking into account the partition coefficient of radon between the organic and aqueous phases in the reservoir is known and the increase in the amount of radon in the aqueous phase, relatively to the amount initially present is accounted for. The methodology has been tested in experiments carried in reduced laboratory scale. A porous medium block prepared in such a way to approximately reproduce the reservoir characteristics has been used in the tests. The block was built out of a sandstone rock containing uranium ore whose radon emanation rate allows precise measurements in small volume samples placed in a coreholder. The steps leading from the formation to the depletion of the reservoir have been simulated...Note: The complete abstract is available with the full electronic document / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

The nuclear power sector has a history of challenges with its relative competitiveness against other forms of electricity generation. The availability of low cost low natural gas, the Fukushima accident, and the cancellation of the AP1000 V.C. Summer project has caused a considerable role in ending the short lived “Nuclear Renaissance.” Historically, the nuclear industry has focused on direct cost reduction through construction, increasing installed capacity, and improving efficiencies to capacity factors in the 1990s and 2000s as ways to maintain competitiveness against other forms of energy generation. With renewables serving as an emerging low-carbon competitor, an added focus needs to be placed on indirect methods to increase the competitiveness of nuclear power. This thesis focuses on establishing pathways where nuclear power can be competitive with other forms of electricity generation given its advantages environmentally with Small Modular Reactors (SMRs), socioeconomically with legacy nuclear power plants, and through passive safety with SMRs. In Chapter 2, I estimate the life cycle GHG emissions and examine the cost of carbon abatement when nuclear is used to replace fossil fuels for the Westinghouse SMR (W-SMR) and AP1000. I created LCA models using past literature and Monte Carlo simulation to estimate the mean (and 90% confidence interval) life cycle GHG emissions of the W-SMR to be 7.4 g of CO2-eq/kwh (4.5 to 11.3 g of CO2-eq/kwh) and the AP1000 to be 7.6 g of CO2-eq/kwh (5.0 to 11.3 g of CO2-eq/kwh). Within the analysis I find that the estimated cost of carbon abatement with an AP1000 against coal and natural gas is $2/tonne of CO2-eq (-$13 to $26/tonne of CO2-eq) and $35/tonne of CO2-eq ($3 to $86/tonne of CO2-eq), respectively. In comparison, a W-SMR the cost of carbon abatement against coal and natural gas is $3/tonne of CO2- eq (-$15 to $28/tonne of CO2-eq) and $37/tonne of CO2-eq (-$1 to $90/tonne of CO2-eq), respectively. I conclude, with the exception of hydropower, the Westinghouse SMR design and the AP1000 have a smaller footprint than all other generation technologies including renewables. Assigning a cost to carbon for natural gas plant or implementing zero-emission incentives can improve the economic competitiveness of nuclear power through environmental competitiveness. The retirement of small and medium-scale coal power plants due the availability of natural gas can provide an opportunity for SMRs to replace that missing capacity. This trade-off between higher costs but lower GHG emissions demonstrates that depending on the value placed on carbon, SMR technology could be economically competitive with fossil fuel technologies Following my environmental competitiveness analysis, I shift towards investigating socioeconomic competitiveness of legacy large scale nuclear power plants compared to baseload coal and natural gas plants. In Chapter 3, I utilize ANOVA models, Tukey’s, and t-tests to explore the socioeconomic characteristics and disparities that exist within counties and communities that contain baseload power plants. My results indicate, relative to the home counties of nuclear plants, communities closer to nuclear plants have higher home values and incomes than those further away. Conversely, communities near coal and natural gas have incomes and home values that increase with distance from the plant. Communities near coal plants are typically either in less wealthy parts of the county or have a similar socioeconomic makeup as county. It can be suggested that equity issues regarding the community characteristics could be included in the discussion of converting existing power plants to use other fuel sources. Communities near power plants are not created equally and have different needs. While communities near nuclear power plants may benefit from the added tax base and absence of emissions, this is not the case for communities near coal and natural gas. With the impending retirement of large scale coal plants, the conversion of these plants to natural gas or small modular reactors presents an opportunity where negative environmental externalities can be reduced while also retaining some of the economic benefits. In Chapter 4, I present a model for estimating environmental dose exposure in a post-accident scenario to support scalable emergency planning zones (EPZs). The model includes calculating radionuclide inventory; estimating the impact decontamination factors from the AP1000, NUREG-6189, and EPRI’s Experimental Verification of Post-Accident iPWR Aerosol Behavior test will have on radioactivity within containment; and estimate dose exposure using atmospheric dispersion models. This work aims to compare historical decontamination factors with updated decontamination factors to outline the impact on containment radioactivity and dose exposure relative to the Environmental Protection Agency’s Protective Action Guide (PAG) limits. On average, I have found the AP1000, Surry, and iPWR produces 139, 153, and 104 curies/ft3 75 minutes after a LOCA. The iPWR produces less radioactivity per volume in containment than the AP1000 and Surry 84% and 96% of the time, respectively. The AP1000 produces less radioactivity per volume than Surry 68% of the time. On average, the AP1000, Surry, and iPWR produces 84,000, 106,000, and 7,000 curies/MWth 75 minutes after a LOCA. The lower bound 5 rem PAG limit is never exceeded for and does not exceeds the 1 rem lower PAG limit for whole body exposure at the 5-mile EPZ using the mean value. Considering this analysis uses a simple worst case Gaussian Plume model for atmospheric dispersion, the findings can be used to in conjunction with the State-of-the-Art Reactor Consequence Analyses (SOARCA) to provide accurate and realistic estimates for exposure. I believe this analysis can help to develop a regulatory basis for technology-neutral, risk-based approach to EPZs for iPWRs. Finally, in Chapter 5 I discuss historical challenges facing the nuclear industry, policy implications, and recommendations. These policy implications and recommendations serve as pathways to frame an new nuclear renaissance. I also recommend future work where I details opportunities for improvements to nuclear competitiveness. Ultimately, this thesis can help policy and decision makers that can improve competitiveness and minimize risk as it relates to the expansion of nuclear power sector.

The utilisation of fossil fuels for energy worldwide depletes the natural reserves and at the same time releases billions of tonnes of carbon dioxide and other greenhouse gases into the atmosphere. In order to reverse the negative effects of this accumulation, i.e., global warming and climatic changes, countries around the world are now considering nuclear energy and other cleaner sources of energy as a substitute to the burning of fossil fuels. The deployment of the later technology has progressed slowly due to lack of public support. The general public and environmental lobbyists worry about the discharge of radioactive waste from nuclear power generation and accidents that have occurred in the nuclear power industry in the recent past. One of pollutants of concern is uranium which is discharged from the nuclear generation processes as the highly toxic uranium-6, (U(VI)). U(VI) coming from the reactors is radioactive as well as highly toxic to aquatic life forms. Biological treatment of metal pollutants is viewed as an environmentally friendly alternative to conventional physical/chemical treatment methods, especially in dilute solutions where physical/chemical methods may not be effective. Microbial processes may be applied both as in situ and/or ex situ processes. Microbial consortia, consisting of several species of microorganisms in the form of bioflocs for reducing/removing the pollutants have been used as they preserve the complex interrelationships that exist between species in the source. The results of this study demonstrate the potential of microbial U(VI) reduction as a possible replacement technology for physical/chemical processes currently in use in the nuclear industry. A detailed analysis of the biological reduction of uranium-(VI) was conducted and the following were the main findings of the study: (1) Background uranium concentration in soil from the mine was determined to be 168 mg/kg, a very high value compared to the typical concentration of uranium in natural soils; (2) Among six bacteria species isolated from a uranium mine in Limpopo, South Africa, three anaerobic species – Pantoea sp., Enterobacter sp. and Pseudomonas stutzeri – reduced U(VI) to U(VI) and facilitated the removal of the uranium species from solution. Based on batch studies and cell disruption studies, the laws governing microbial U(VI) reduction were determined and the kinetic parameters for U(VI) reduction were determined. The cultures in this study reduced uranium-U(VI) at a rate better than rates found in literature for other microorganisms. Reduction rates reported in this paper can be used to assess the applicability of bioreduction for uranium removal processes. / Dissertation (MSc)--University of Pretoria, 2011. / Chemical Engineering / unrestricted

No description available.

This thesis proposes that the nuclear age offered high modernity and technological nationalism a central position in the making of modern Canada. The nuclear age influenced modern Canada’s social, economic, and political history and it did so by telling Canadians they were, essentially, a modern people governed by a modern state. From the 1940s to the end of the 1970s, Canada’s development of the nuclear industry reflected the pursuit of science and technology to create modern forms of energy production. Canadians were urged to see in nuclear power a way of remaining competitive in a changing global order. It offered them new industries at many stages of the nuclear cycle. The post-war era reflected a changing direction in the country’s central ideological direction – one defined since the 1840s by liberalism and a subordinate role in the British Empire. The creation of the Canadian nuclear cycle signified a transition to a new stage in which Canada, now imagined by some to be a nation, actively sought out modern forms of social and economic progress. Nuclear energy systems came to fruition at a moment when Canada was establishing new directions as a sovereign state vying for greater global political and economic influence on the global stage. This thesis argues that this pattern was no mere coincidence: this technological nationalism was the logical outcome of deep-seated tendencies. Yet, many citizens remained skeptical of the nuclear age’s possibilities. Although the federal government had established its nuclear cycle to develop the peaceful uses of atomic energy, its birth in the shadows of the Second World War and the Manhattan Project also provoked a widespread sense of discomfort. The dropping of the atomic bomb in 1945 solidified fears of nuclear energy long before the AECL built its first reactor on the shores of Lake Huron. Canadians en masse rejected the country’s participation in the development of nuclear weapons and, as Lester Pearson learned to his cost in 1963, were adamant that Canada should remain a nuclear-weapons-free nation. Successive governments in the 1950s and 1960s faced public backlash regarding Canada’s complicity in the stockpiling of nuclear arms, the production of uranium for American weapons, and its involvement in weapons tests. Born out of the peace movements and ecological movements of the 1960s, anti-nuclear groups emerged in the 1970s to oppose the nuclear industry. These groups shared members, ideas, and momentum, and the chasm between anti-war and environmental activism was progressively bridged as the 1970s proceeded. Both the anti-nuclear and anti-bomb activists were essential to challenging the path and direction of the Canadian nuclear system and its role in creating political and environmental uncertainty. Such fears remained a constant social reminder throughout the post-war era of the mutually assured destruction associated with atomic energy and the Cold War arms race. Indeed, Canada’s peaceful nuclear program did not always seem so peaceable, as activists in both camps argued more and more empathetically. Canada’s nationalistic pursuit of a nuclear modernity also entailed the quest of a narrow form of utopianism – one in which a future-oriented Canada provided greater social and economic freedoms under the aegis of liberal democracy. At the community level, nuclear energy symbolized the changing senses and sensibilities of living through modernity – the perception that the core structures of society were giving way to new social realities and that the relations of time and space were shifting. While nuclear energy symbolized the social and economic benefits of the cultural revolution of the nuclear age, it also aroused the concerns and fears about modernity. The conflicts between the pro- and anti-nuclear movements of the 1970s and 1980s were in many respects an extension of debates over high modernity and techno-nationalism. / Thesis / Candidate in Philosophy / This thesis explores the history of Canada’s nuclear age between 1942 and 1979 and examines how both Canadians and the state perceived the development of the country’s nuclear industry. It examines how Canada gained entrance into the nuclear club – joining the ranks of the Manhattan Project – its post-war developments in nuclear power, and the ways in which nuclear energy bolstered a form of nationalism predicated on technological prowess. The need to develop Canada’s nuclear industry reflected the larger social, political, and economic changes occurring in the post-war era. In many ways, the history of Canada’s nuclear age is the history of how societies act and react to modernity – the radical transformation of perceptions of space and time. This thesis examines that process of change and its influence on Canadians’ responses to the modern world around them.

<p> The unique features of the Interrupted Thorium Cycle owing to Pa-233 have been examined including possible implications for practical implementation of the cycle. Generalized trajectories for the fuel inventories of fusion-fission symbionts are derived through a comprehensive parametric analysis. The resultant formulations are then applied to a specific example. It is concluded that this formulation and analysis leads to more exact fissile and fusile fuel characterizations than suggested by conventional procedures. </p> / Thesis / Master of Engineering (MEngr)

Thesis (M.B.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / There are a number of nuclear reactor types. It will be a purpose of this thesis to examine both a power reactor and a research reactor to determine what inherent measures, as well as applied measures, safety controls, and techniques are used in attempting to make nuclear reactor operations safe. Whereas nuclear reactors are extremely expensive and applicable to only a limited number of industries, radioisotopes, the unstable form of various elements, offers to a much larger industrial family a useful, inexpensive, and simple tool. A second purpose of this thesis will be to observe, describe, and evaluate the use and application of radioisotopes as they are currently being employed in industry, with particular reference to safety features. / 2031-01-01