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Made available in DSpace on 2014-10-09T12:34:34Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:07Z (GMT). No. of bitstreams: 0 / A chave para o renascimento nuclear é a aceitação pública. Diante das necessidades energéticas que existem em todo o mundo e da escassez dos recursos disponíveis, o trabalho de caracterizar e propor novos modelos para representar a opinião pública é de extrema importância a todos os interessados. Embora o estudo da percepção pública sobre riscos seja recente, diversas abordagens do assunto foram sugeridas e apresentadas, em especial o tema das percepções acerca das instalações nucleares. A definição atual de risco, que transita entre modelos objetivos e subjetivos, reflete as opiniões frequentemente conflitantes do público e de especialistas nesse assunto. Estratégias de comunicação com o público podem ser julgadas a partir dos diversos modelos criados, e seus resultados registrados. O uso de modelos estruturais pode conferir um caráter tanto exploratório quanto confirmatório, sendo assim uma ferramenta adequada para desenvolver estudos sobre o tema da percepção pública em geral. Neste trabalho, um modelo estrutural é reapresentado a partir de dados obtidos num estudo anterior e completado com dados coletados depois do acidente nuclear de Fukushima, no Japão. Os efeitos causados por esse acidente ofereceram uma oportunidade única de estudar a opinião pública por meio dos efeitos de um acidente nuclear e a comunicação de riscos. Paralelamente a esse fato, buscou-se reavaliar o modelo estrutural de acordo com os resultados obtidos, de modo a sustentar um aprimoramento constante das ferramentas de trabalho. Ainda, uma comparação dos dados para grupos de interesse na modelagem de risco é apresentada, especificamente para os grupos de indivíduos do público e especialistas e em seguida, para grupos de alunos antes e depois de uma visita educativa à usina nuclear Almirante Álvaro Alberto. Como resultados, para os modelos estruturais, os dados obtidos foram aplicados aos modelos e analisados por meio de uma análise estrutural da matriz de correlação das variáveis latentes, da magnitude dos coeficientes estruturais e os valores de R2. Resultados indicam que a opinião pública mantém sua rejeição, e que a percepção de benefícios, frente aos riscos percebidos após o acidente, diminuiu. O novo modelo tratou de incluir a variável latente correspondente aos fatores emocionais, cujos resultados aumentaram a explicação da variável dependente, denominada propensão a aceitar energia nuclear. Já para os grupos analisados, a diferença de opinião entre os grupos segue as características esperadas em cada grupo, e indica alguns pontos de interesse para estratégias de comunicação e entendimento da formação opinião pública e de especialistas. Os efeitos da visita indicam que esta melhora a percepção de benefícios e reduz a percepção de medo e risco, mas que seus resultados podem ser insuficientes para promover uma mudança sólida numa opinião negativa em relação a estas instalações. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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The fission product releases from spherical fuel elements used in modern high temperature gas cooled reactors are one of the first source terms used in describing the safety of planned nuclear plants during normal and accident conditions. The verification and validation of the model and code used to predict the gaseous fission product behaviour and release from spherical fuel elements for the PBMR were documented in this dissertation. The PBMR is the latest design in high temperature gas cooled reactor technology utilizing spherical fuel elements based on the LEU TRISO-coated particle design. Fission products can be divided into relatively short-lived noble gas and halogens, and relatively long-lived metallic fission and activation products. Each group is described by its own models and sets of transport parameters. The noble gases and halogen fission product releases from the fuel elements are direct indications of fuel performance and are modelled by the Booth equation. The fission product release legacy code NOBLEG for noble gases and halogens was developed previously to calculate this diffusion model for high temperature reactors. The model and code are verified and validated for use in PBMR design and analyses under normal operating conditions. The history of irradiation experiments conducted on coated fuel particles and spherical fuel elements was investigated, and the most suitable irradiation tests with their post irradiation investigations were identified for the purpose of validation of the model and code. The model used to determine gaseous fission product behaviour and release from spherical fuel elements is described in detail. The application of this model in the code is verified mathematically with the Booth model, and by inspection of the source code. The thermohydraulic model used by NOBLEG to calculate fuel temperatures is verified with code to code comparisons with the core neutronics code VSOP. The irradiation tests HFR-K5 and -K6 were selected to validate the gaseous fission product code NOBLEG. An investigation was done into the development of NOBLEG to calculate gaseous fission product release under oxidizing conditions caused by water ingress events. New relationships were derived from water vapour injection tests done during the irradiation experiment HFR-K6, that allows NOBLEG to estimate the increase in gaseous fission product release under oxidizing conditions. A new model was proposed to explain peculiarities observed during the water injection tests. / Prof. P.P. Coetzee

No description available.

Bibliography: pages 168-174. / The Emergency Electric Power Supply Systems at Pressurized Water Reactor Nuclear Power Plants are reviewed, problem areas are identified, and recommendations are made for existing and future Nuclear Power Plants. A simplified introduction to a typical Pressurized Water Nuclear Reactor is given and the problems associated with the commercial use of nuclear power are discussed. An overview of the Nuclear industry's solutions is presented and covers the Reliability of equipment and the American Regulatory requirements. The alternating and direct current power supply systems are examined in terms of plant operational state and equipment type (Diesel generators, Grid network, Lead-acid batteries, Battery chargers, Inverters, and Power Distribution networks). The trends in the design of Emergency Electric Power supply systems at Nuclear Power Plants are presented. The loss of all alternating current power, known as Station Blackout, is discussed and the American and European response to this. problem is presented. Problems experienced in the direct current systems are discussed and solutions are presented. The experience at Koeberg Nuclear Power station with Lead-acid batteries is included in the discussion. The thesis concludes with recommendations for designers and operators of the Electric Power Supply Systems at Nuclear Power Stations.

The purpose of this essay is to perform an empirical test of the hypothesis that distance to an operative nuclear power plant will affect property pricing. The focus is on three counties in Sweden that have nuclear power plants. The hedonic pricing method is employed to fulfill the purpose. This involves an econometric cross-section analysis where the price of a property is assumed to be influenced by various housing characteristics, a distance variable, and time specific effects. The data were provided by Svensk Mäklarstatistik and were collected from the period 2005-2021. The material included information regarding property prices and property characteristics. The results suggest that there is a positive statistical relationship between the level of property prices and the distance to an operative nuclear power plant. However, we only find this relationship for Varberg and Oskarshamn. This result is in some contrast to the findings of a few previous studies. / Syftet med denna uppsats är att genomföra ett empiriskt test av hypotesen att avståndet till ett operativt kärnkraftverk påverkar nivån på fastighetspriserna i de tre kommuner i Sverige som har etablerade kärnkraftverk. Detta syfte besvaras genom att tillämpa den så kallade fastighetsvärdemetoden. En ekonometrisk modell specificeras där den beroende variabeln, priset på en fastighet, förklaras av olika karakteristik hos fastigheten samt bostaden, avståndet till närmaste operativa kärnkraftverk, och tidsspecifika effekter. Datamaterialet samlades in från Svensk Mäklarstatistik och innehöll data från tidsperioden 2005 till 2021. Datamaterialet bestod av fastighetspriser samt fastigheternas karaktärsdrag. Resultaten visar att det finns ett positivt statistiskt samband mellan nivån på fastighetspriserna och avståndet till ett operativt kärnkraftverk. Fastighetspriserna tenderar, allt annat lika, att vara lägre på platser som ligger nära kärnkraftverket men detta resultat erhålls endast för Varberg och Oskarshamn. Uppsatsens resultat skiljer sig åt från ett flertal tidigare studier.

Thesis (Nucl. E.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographies and index. / by Claudio Daniel Antonini. / Nucl.E.