Orientador: Elias Basile Tambourgi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-04T05:25:21Z (GMT). No. of bitstreams: 1 Mesquita_AmirZacarias_D.pdf: 6016264 bytes, checksum: 00f6515432485b46007d7639b12802fc (MD5) Previous issue date: 2005 / Resumo: O Reator Nuclear de Pesquisa TRIGA IPR-RI completou em novembro de 2004, 44 anos de operação. Inicialmente sua potência máxima era de 30 kW térmicos, posteriormente acrescentaram-se mais elementos combustíveis ao núcleo aumentando a potência para 100 kW, sendo esta a atual potência licenciada. Novos combustíveis foram acrescentados recentemente permitindo que a potência atinja níveis de 250 kW. O TRIGA IPR-RI é um reator de piscina com o núcleo refrigerado por circulação natural. Apesar dos vários trabalhos de pesquisa realizados nesta instalação, notadamente em ativação neutrônica, existe uma carência de dados termo-hidráulicos teóricos e experimentais sobre seu funcionamento. Sendo assim rea1izou-se-se uma série de testes experimentais dando enfoque a medidas de temperatura no centro do elemento combustível, no núcleo e no poço, com o reator operando em vários níveis de potência. As experiências aqui relatadas fazem parte da programação de pesquisas do CDTN/CNEN, que têm como objetivo comissionar o Reator TRIGA IPR-RI para a operação rotineira a 250 kW. Este trabalho descreve os estudos analíticos e experimentais realizados com o intuito de determinar a distribuição das temperaturas no reator. Desenvolveu-se uma metodologia para a calibração e monitoração da potência dissipada pelo núcleo, implantando assim novos canais de medida de potência por processo térmico. A condutividade térmica do elemento combustível e o coeficiente de transferência de calor de seu revestimento para o refrigerante foram avaliados experimentalmente. Foi proposta uma formulação para a determinação do valor da condu1ância na interface entre combustível e seu revestimento (gap). Os resultados experimentais foram comparados com valores teóricos encontrados na literatura. Como subsídio às experiências, desenvolveu-se um sistema e um programa de coleta e processamento de dados para o reator, capaz de acompanhar em tempo real e registrar seus - principais parâmetros operacionais. As experiências realizadas permitiram uma melhor compreensão do comportamento termofluidodinâmico do reator, ajudando no aperfeiçoamento de sua modelagem e contribuindo para a sua segurança operacional / Abstract: The TRIGA-IPR-R1 Research Nuclear Reactor has completed 44 years in operation in November 2004. Its initial nominal thermal power was 30 kW. In 1979 its power was increased to 100 kW by adding new fuel elements to the reactor. Recently some more fuel elements were added to the core increasing the power to 250 kW. The TRIGA-IPR-R1 is a pool type reactor with a natural circulation core cooling system. Although the large number of experiments had been carried out with this reactor, mainly on neutron activation analysis, there is not many data on its thermal-hydraulics processes, whether experimental or theoretical 80 a number of experiments were carried out with the measurement of the temperature inside the fuel element, in the reactor core and along the reactor pool. During these experiments the reactor was set in many different power levels. These experiments are part of the CDTN/CNEN research program, and have the main objective of commissioning the 1RIGA-IPR-Rl reactor for routine operation at 250 kW. This work presents the experimental and theoretical analyses to determine the temperature distribution in the reactor. A methodology for the calibration and monitoring the reactor thermal power was also developed. This methodology allowed adding others power measuring channels to 1he reactor by using thermal processes. The fuel thermal conductivity and the heat transfer coefficient from the cladding to the coolant were also experimentatly valued. It was also presented a correlation for the gap conductance between the fuel and the cladding. The experimental results were compared with theoretical calculations and with data obtained from technical literature. A data acquisition and processing system and a software were developed to help the investigation. This system allows on line monitoring and registration of the main reactor operational parameters. The experiments have given better comprehension of the reactor thermal-fluid - dynamics and helped to develop numerical models, contributing to operational safety improvements / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

Das, dem Teilprojekt zu Grunde liegende, Gesamtprojekt gliederte sich in zwei Module: In Modul A (Förderung durch das BMWi, Federführung durch KIT) und Modul B (Förderung durch das BMBF, Federführung durch acatech). Projektpartner im Modul A waren DBE TECHNOLOGY GmbH, die Gesellschaft für Anlagen- und Reaktorsicherheit mbH (GRS), das Helmholtz-Zentrum Dresden-Rossendorf (HZDR), das Karlsruher Institut für Technologie (KIT) und die Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen zusammen mit dem Forschungszentrum Jülich (FZJ). Modul B wurde vom Zentrum für Interdisziplinäre Risiko- und Innovationsforschung der Universität Stuttgart (ZIRIUS) bearbeitet. Die Gesamtkoordination der beidem Module erfolgte durch die Deutsche Akademie der Technikwissenschaften (acatech). Auf Grundlage einer Analyse der wissenschaftlich-technischen Aspekte durch Modul A wurden die gesellschaftlichen Implikationen bewertet und daraus in Modul B Kommunikations- und Handlungsempfehlungen für die zukünftige Positionierung von P&T formuliert. Im, vom HZDR koordinierten, Teilprojekt „Stand der Grundlagen- und technologischen Forschung“ wird eine Übersicht über den genannten Bereich gegeben. Eingeführt wird das Thema mit einer Kurzbeschreibung möglicher Reaktorsysteme für die Transmutation. Danach wird der Entwicklungsstand der Spezialbereiche Trennchemie, Sicherheitstechnologie, Beschleunigertechnologie Flüssigmetalltechnologie, Entwicklung von Spallationstargets, Transmutationsbrennstoffen und Werkstoffkonzepten sowie Konditionierung von Abfällen, beschrieben. Dies wird ergänzt durch Spezifika von Transmutationsanlagen beginnend bei physikalischen Grundlagen und Kerndesigns, über Reaktorphysik von Transmutationsanlagen, Simulationstools und die Entwicklung von Safety Approaches. Im Anschluss wird der Stand existierender Bestrahlungseinrichtungen mit schnellem Spektrum beschrieben. Nachfolgend werden basierend auf dem derzeitigen Stand von F&E die offenen Fragen und Forschungslücken in den einzelnen Teilbereichen – Wiederaufbereitung und Konditionierung, Beschleuniger und Spallationstarget, Reaktor – zusammengestellt und sowohl eine Strategie, als auch ein Fahrplan zur Schließung der Technology Gaps entwickelt. Zusätzlich werden die Hauptbeiträge, des HZDR zur Gesamtstudie beschrieben. Dies sind insbesondere die Beschreibungen der Möglichkeiten und Grenzen von P&T, die Herausforderungen an Bestrahlungseinrichtungen zur Transmutation und deren Effektivität, sowie Sicherheitsmerkmale beschleuniger-getriebener unterkritischer Systeme inclusive grundlegender Störfallbetrachtungen und Sicherheitscharakteristik. / The main project, where this sub project contributed to, has been structured into two modules: module A (funded by the federal ministry of economics, managed by KIT) and module B (funded by the federal ministry of education and research, managed by acatech). Partners in module A were DBE TECHNOLOGY GmbH, the Gesellschaft für Anlagen- und Reaktorsicherheit mbH (GRS), the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Karlsruher Institute of Technology (KIT) and the Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, in co-operation with the Forschungszentrum Jülich (FZJ). Modul B has been executed by the Zentrum für Interdisziplinäre Risiko- und Innovationsforschung der Universität Stuttgart (ZIRIUS). The overall coordination has been carried out by the Deutsche Akademie der Technikwissenschaften (acatech). The social implications have been evaluated in module B based on the analysis of the scientific and technological aspects in module A. Recommendations for communication and actions to be taken for the future positioning of P&T have been developed. In the project part, coordinated by HZDR – status of R&D – an overview on the whole topic P&T is given. The topic is opened by a short description of reactor systems possible for transmutation. In the following the R&D status of separation technologies, safety technology, accelerator technology, liquid metal technology, spallation target development, transmutation fuel and structural material development, as well as waste conditioning is described. The topic is completed by the specifics of transmutation systems, the basic physics and core designs, the reactor physics, the simulation tools and the development of Safety Approaches. Additionally, the status of existing irradiation facilities with fast neutron spectrum is described. Based on the current R&D status, the research and technology gaps in the topics: separation and conditioning, accelerator and spallation target, and reactor are characterized and a strategy as well as a roadmap for closing these gaps has been developed. In addition the major contributions of HZDR to the main project are described. The major parts are the description of the potential and the limits of P&T, the requirements and challenges for transmutation systems and the related efficiency, as well as the safety features of accelerator driven subcritical systems including the transient behavior and the safety characteristics.

Esta dissertação analisa a circunstância conjuntural interna e a externa que viabilizaram a assinatura do Acordo de Cooperação no Campo dos Usos Pacíficos da Energia Nuclear entre os governos de Brasil e Alemanha Federal em 1975. Nossa pretensão é de resgatar o tratamento da questão nuclear no Brasil, a partir da introdução dessa temática no mundo, ou seja, a partir de 1945, até o final do governo Geisel, em 1979. Enfatizamos a realização do acordo nuclear teuto-brasileiro, que, aparentemente, materializaria o desejo do regime militar brasileiro de tornar o Brasil um país nuclearizado. A pesquisa apresenta, ainda, as relações políticas divergentes entre Washington e Brasília durante o governo Geisel, cuja trajetória de desgastes tornou-se a mais acentuada da história na relação entre os dois países. A conclusão obtida valeu-se de argumentos que foram amparados no exame da cronologia acima delimitada, através da perspectiva das relações internacionais e sob as orientações de economia e política externa concebidas pelo governo Geisel. / This dissertation analyzes the internal and external conjuncture which turned possible the signature of the Agreement of Cooperation in the Field of Pacific Use of Nuclear Energy between the governments of Brazil and Federal Germany in 1975. Our aim is to rescue the treatment of the nuclear matter in Brazil, after the introduction of this theme in the world, that is, after 1945 until the end of the Geisel government in 1979. We emphasize the achievement of the German-Brazilian nuclear agreement which, apparently, would materialize the wish of the Brazilian military regiment to transform Brazil in a nuclearized country. This research also presents the problematic political relations between Washington and Brasilia during the Geisel government, in which the route of deterioration has become the strongest in history in the relation between the two countries. The conclusion we obtained used the arguments which were based on the analysis of the chronology mentioned before, through the perspective of the international relations and under the orientations of economy and external policy conceived by the Geisel government.

Esta dissertação analisa a circunstância conjuntural interna e a externa que viabilizaram a assinatura do Acordo de Cooperação no Campo dos Usos Pacíficos da Energia Nuclear entre os governos de Brasil e Alemanha Federal em 1975. Nossa pretensão é de resgatar o tratamento da questão nuclear no Brasil, a partir da introdução dessa temática no mundo, ou seja, a partir de 1945, até o final do governo Geisel, em 1979. Enfatizamos a realização do acordo nuclear teuto-brasileiro, que, aparentemente, materializaria o desejo do regime militar brasileiro de tornar o Brasil um país nuclearizado. A pesquisa apresenta, ainda, as relações políticas divergentes entre Washington e Brasília durante o governo Geisel, cuja trajetória de desgastes tornou-se a mais acentuada da história na relação entre os dois países. A conclusão obtida valeu-se de argumentos que foram amparados no exame da cronologia acima delimitada, através da perspectiva das relações internacionais e sob as orientações de economia e política externa concebidas pelo governo Geisel. / This dissertation analyzes the internal and external conjuncture which turned possible the signature of the Agreement of Cooperation in the Field of Pacific Use of Nuclear Energy between the governments of Brazil and Federal Germany in 1975. Our aim is to rescue the treatment of the nuclear matter in Brazil, after the introduction of this theme in the world, that is, after 1945 until the end of the Geisel government in 1979. We emphasize the achievement of the German-Brazilian nuclear agreement which, apparently, would materialize the wish of the Brazilian military regiment to transform Brazil in a nuclearized country. This research also presents the problematic political relations between Washington and Brasilia during the Geisel government, in which the route of deterioration has become the strongest in history in the relation between the two countries. The conclusion we obtained used the arguments which were based on the analysis of the chronology mentioned before, through the perspective of the international relations and under the orientations of economy and external policy conceived by the Geisel government.

South Africa is in the critical process of determining the profile of its power composition for the next 30 years and beyond. From the IRP2010 it seems that too much emphasis is placed on renewable energy, coal and other technologies and too little on nuclear power. In the revision of the IRP2010, the renewable portion of the energy composition has been increased substantially from 11.4 to 17.8GW, where nuclear remains on 9.6GW (DME, 2011). The purpose of this research is to investigate and compare power-generating technologies. The investigation of the different technologies is corroborated through modelling the IRP2010 planned energy mix efficiency, as well as a proposed energy mix. These models will be built using Microsoft Excel. Topics not investigated are socio-economic impacts and politics around nuclear energy in South Africa. The main finding of the research is that nuclear power is the best option for base load energy in order to meet South Africa‟s growing demand for electricity. It has the highest load factor, longest economic life, best safety record, adheres to the Kyoto protocol, uses the least fresh water and is economically competitive. It addresses all the concerns stipulated in the IRP2010 and the technology also offers benefits outside the electricity industry, such as the mining, medical, agriculture and research sectors. This versatile, reliable and powerful technology holds great benefits and has the potential to uplift the quality of life for the whole South African nation. / MSc (Nuclear Engineering), North-West University, Potchefstroom Campus, 2015

South Africa is in the critical process of determining the profile of its power composition for the next 30 years and beyond. From the IRP2010 it seems that too much emphasis is placed on renewable energy, coal and other technologies and too little on nuclear power. In the revision of the IRP2010, the renewable portion of the energy composition has been increased substantially from 11.4 to 17.8GW, where nuclear remains on 9.6GW (DME, 2011). The purpose of this research is to investigate and compare power-generating technologies. The investigation of the different technologies is corroborated through modelling the IRP2010 planned energy mix efficiency, as well as a proposed energy mix. These models will be built using Microsoft Excel. Topics not investigated are socio-economic impacts and politics around nuclear energy in South Africa. The main finding of the research is that nuclear power is the best option for base load energy in order to meet South Africa‟s growing demand for electricity. It has the highest load factor, longest economic life, best safety record, adheres to the Kyoto protocol, uses the least fresh water and is economically competitive. It addresses all the concerns stipulated in the IRP2010 and the technology also offers benefits outside the electricity industry, such as the mining, medical, agriculture and research sectors. This versatile, reliable and powerful technology holds great benefits and has the potential to uplift the quality of life for the whole South African nation. / MSc (Nuclear Engineering), North-West University, Potchefstroom Campus, 2015

Approved for public release; distribution in unlimited. / Since the end of the Cold War, NATO has attributed great importance to the development of cooperation with Russia. This thesis, first, evaluates the main developments in NATO - Russian relations since 1991. Although Moscow and the Alliance established a NATO - Russia Council (NRC) and asserted the initiation of a qualitatively new relationship, Russia still needs to fulfill some requirements for catching up the Western standards. Russia's external relations and political, economic and security factors internal to Russia will determine the future of the relationship. This thesis examines Russia's political development and transformation of its economic system, and establishes the problems in its political and economic systems. It also examines Russia's problematic external relations in the region, and their impact on the NATO - Russian relationship. It looks into Russia's National Security Concept, explores regional conflicts such as Chechnya and Georgia, and the U.S. - NATO presence in Central Asia. Then, it examines the oil and natural gas transportation problems created by the Russian monopoly, and evaluates Russian technology transfers to Iran, particularly in the nuclear sector. Consequently, it evaluates the internal and external interactions mentioned above and offers conclusions about the prospects for security and stability in Europe. / Lieutenant, Turkish Navy

Embora a tecnologia nuclear tenha aplicações benéficas para diversas áreas, como saúde, indústria, agricultura, produção de energia, entre outras, a sua aceitação ainda é restrita e há várias barreiras para o seu uso. A falta de conhecimento assertivo sobre essa tecnologia gera preconceito com relação à sua utilização. Preconceitos podem ser explícitos, que são conscientes, ou implícitos, inconscientes. No entanto, conscientes ou inconscientes, eles influenciam o comportamento e as atitudes. As experiências nas memórias explícita e implícita podem ser transferidas de uma para a outra. Assim, preconceitos ou associações inconscientes podem ser modificados pela memória explícita, ou seja, um novo conhecimento pode reduzi-los ou revertê-los. Para uma educação transformadora, o professor tem um papel central; entretanto, para que ele transmita o conhecimento de forma imparcial, é necessário que tenha uma visão livre de preconceitos. Esse trabalho visa desenvolver uma metodologia com apoio em neurociências por meio da qual as associações implícitas referentes às aplicações da tecnologia nuclear por parte dos professores de ciências sejam identificadas e possíveis preconceitos implícitos sejam modificados por meio de novos conhecimentos explícitos. Para identificar preconceitos implícitos são necessários testes específicos de memória implícita. O Teste de Associação Implícita (TAI) foi selecionado para esse trabalho. Seguindo as etapas fornecidas pelo software FreeIAT, o TAI foi customizado a fim de comparar as associações implícitas de participantes com relação às áreas nuclear e petróleo e sua consistência foi averiguada por um pré-teste aplicado a um grupo de especialistas (grupo controle) e de leigos, cujos resultados determinaram um bom valor de Alfa de Cronbach. Um programa multissensorial de 5 horas foi desenvolvido e realizado no Instituto de Pesquisas Energéticas e Nucleares (IPEN) para um grupo de professores de ciências. O TAI foi aplicado no início e ao término do programa e os resultados das associações implícitas foram comparados. Após seis meses, o TAI foi reaplicado ao mesmo grupo de professores para verificar se as associações implícitas se mantiveram estáveis. Esse programa multissensorial foi comparado com um programa de 12 semanas de ensino tradicional com aulas expositivas realizado no IPEN para alunos ingressantes na pós-graduação. O programa multissensorial foi efetivo para mudar e manter as associações implícitas dos professores referentes às aplicações benéficas da tecnologia nuclear, diferentemente do ensino tradicional com aulas expositivas. Esse trabalho demonstrou que é possível quebrar paradigmas e preconceitos. A abordagem multissensorial possibilitou um conhecimento enriquecido sobre as aplicações da tecnologia nuclear, ou seja, promoveu novas experiências na memória explícita que modificaram as associações prévias armazenadas na memória implícita. Assim, o programa multissensorial demonstrou ser uma ferramenta eficaz, capaz de produzir e manter mudanças nas associações implícitas, de baixo custo e pode ser aplicado em diversas áreas para mudar as associações implícitas e reverter preconceitos. Os resultados demonstraram que esse trabalho de doutorado teve êxito no que se propôs, contribuindo, assim, para a difusão do conhecimento das aplicações benéficas da tecnologia nuclear e, consequentemente, para a sua desmitificação. Essa metodologia completa poderá ser empregada em outras áreas para identificar, modificar e/ou reverter preconceitos ou estereótipos implícitos. / Although the applications of nuclear technology benefit several fields, such as health, industry, agriculture, energy production, among others, its public acceptance is still reduced and there are various barriers to its use. A lack of assertive knowledge about this technology generates prejudice against its use. Prejudices may be explicit at the conscious level or implicit operating outside awareness. Nevertheless, either conscious or unconscious, prejudices interfere with behavior and attitudes. The experiences in the explicit and implicit memories can be transferred from one to the other; thus unconscious prejudices or associations may be modified by the explicit memory, that is, new knowledge may reduce or even reverse them. The teachers play a critical role for transforming education; however, for sharing balanced knowledge they must have a perspective without prejudices. This work aims to develop a neuroscience-based methodology through which implicit associations of Brazilian science teachers towards nuclear technology may be assessed and possible implicit prejudices may be changed by new knowledge. In order to identify implicit prejudices, specific implicit memory tests are required. The Implicit Association Test (IAT) was chosen for this work. By following the steps provided by the software FreeIAT, the IAT was customized aiming to compare the implicit associations of respondents towards nuclear and oil. A pretest with nuclear specialists (control group) and lay people was administered to check the consistency of the customized IAT. The Cronbach\'s alpha was applied to measure the reliability of the test and showed good internal consistency. A 5-hour multisensory program for science teachers was designed and administered at the Instituto de Pesquisas Energéticas e Nucleares (IPEN). The IAT was administered at the beginning and at the end of the program and the results of the implicit associations were compared. After a six-month period, the IAT was re-administered to the same group of teachers to verify whether the implicit associations remained stable. This multisensory program was compared to a 12-week traditional teaching program with lecture classes held at IPEN for incoming post-graduation students. The multisensory program was effective for changing and maintaining the implicit associations of teachers towards the beneficial applications of nuclear technology, unlike the traditional teaching program with lecture classes. This work demonstrated that it is possible to break paradigms and prejudices. The multisensory program enabled an enriched knowledge about the applications of nuclear technology, that is, it promoted new experiences in the explicit memory, which modified the previous associations stored in the implicit memory. Therefore, the multisensory program has proven to be a successful, cost-effective tool, which is able to cause and maintain changes in implicit associations and can be applied in several areas where changes in implicit associations and prejudice reversal are desired. The results demonstrated that the proposed doctoral research was effective, thus contributing to the diffusion of knowledge of the beneficial applications of nuclear technology and, consequently, to its demythification. This methodology may be administered to other fields to identify, modify and/or reduce implicit prejudices or stereotypes.

Embora a tecnologia nuclear tenha aplicações benéficas para diversas áreas, como saúde, indústria, agricultura, produção de energia, entre outras, a sua aceitação ainda é restrita e há várias barreiras para o seu uso. A falta de conhecimento assertivo sobre essa tecnologia gera preconceito com relação à sua utilização. Preconceitos podem ser explícitos, que são conscientes, ou implícitos, inconscientes. No entanto, conscientes ou inconscientes, eles influenciam o comportamento e as atitudes. As experiências nas memórias explícita e implícita podem ser transferidas de uma para a outra. Assim, preconceitos ou associações inconscientes podem ser modificados pela memória explícita, ou seja, um novo conhecimento pode reduzi-los ou revertê-los. Para uma educação transformadora, o professor tem um papel central; entretanto, para que ele transmita o conhecimento de forma imparcial, é necessário que tenha uma visão livre de preconceitos. Esse trabalho visa desenvolver uma metodologia com apoio em neurociências por meio da qual as associações implícitas referentes às aplicações da tecnologia nuclear por parte dos professores de ciências sejam identificadas e possíveis preconceitos implícitos sejam modificados por meio de novos conhecimentos explícitos. Para identificar preconceitos implícitos são necessários testes específicos de memória implícita. O Teste de Associação Implícita (TAI) foi selecionado para esse trabalho. Seguindo as etapas fornecidas pelo software FreeIAT, o TAI foi customizado a fim de comparar as associações implícitas de participantes com relação às áreas nuclear e petróleo e sua consistência foi averiguada por um pré-teste aplicado a um grupo de especialistas (grupo controle) e de leigos, cujos resultados determinaram um bom valor de Alfa de Cronbach. Um programa multissensorial de 5 horas foi desenvolvido e realizado no Instituto de Pesquisas Energéticas e Nucleares (IPEN) para um grupo de professores de ciências. O TAI foi aplicado no início e ao término do programa e os resultados das associações implícitas foram comparados. Após seis meses, o TAI foi reaplicado ao mesmo grupo de professores para verificar se as associações implícitas se mantiveram estáveis. Esse programa multissensorial foi comparado com um programa de 12 semanas de ensino tradicional com aulas expositivas realizado no IPEN para alunos ingressantes na pós-graduação. O programa multissensorial foi efetivo para mudar e manter as associações implícitas dos professores referentes às aplicações benéficas da tecnologia nuclear, diferentemente do ensino tradicional com aulas expositivas. Esse trabalho demonstrou que é possível quebrar paradigmas e preconceitos. A abordagem multissensorial possibilitou um conhecimento enriquecido sobre as aplicações da tecnologia nuclear, ou seja, promoveu novas experiências na memória explícita que modificaram as associações prévias armazenadas na memória implícita. Assim, o programa multissensorial demonstrou ser uma ferramenta eficaz, capaz de produzir e manter mudanças nas associações implícitas, de baixo custo e pode ser aplicado em diversas áreas para mudar as associações implícitas e reverter preconceitos. Os resultados demonstraram que esse trabalho de doutorado teve êxito no que se propôs, contribuindo, assim, para a difusão do conhecimento das aplicações benéficas da tecnologia nuclear e, consequentemente, para a sua desmitificação. Essa metodologia completa poderá ser empregada em outras áreas para identificar, modificar e/ou reverter preconceitos ou estereótipos implícitos. / Although the applications of nuclear technology benefit several fields, such as health, industry, agriculture, energy production, among others, its public acceptance is still reduced and there are various barriers to its use. A lack of assertive knowledge about this technology generates prejudice against its use. Prejudices may be explicit at the conscious level or implicit operating outside awareness. Nevertheless, either conscious or unconscious, prejudices interfere with behavior and attitudes. The experiences in the explicit and implicit memories can be transferred from one to the other; thus unconscious prejudices or associations may be modified by the explicit memory, that is, new knowledge may reduce or even reverse them. The teachers play a critical role for transforming education; however, for sharing balanced knowledge they must have a perspective without prejudices. This work aims to develop a neuroscience-based methodology through which implicit associations of Brazilian science teachers towards nuclear technology may be assessed and possible implicit prejudices may be changed by new knowledge. In order to identify implicit prejudices, specific implicit memory tests are required. The Implicit Association Test (IAT) was chosen for this work. By following the steps provided by the software FreeIAT, the IAT was customized aiming to compare the implicit associations of respondents towards nuclear and oil. A pretest with nuclear specialists (control group) and lay people was administered to check the consistency of the customized IAT. The Cronbach\'s alpha was applied to measure the reliability of the test and showed good internal consistency. A 5-hour multisensory program for science teachers was designed and administered at the Instituto de Pesquisas Energéticas e Nucleares (IPEN). The IAT was administered at the beginning and at the end of the program and the results of the implicit associations were compared. After a six-month period, the IAT was re-administered to the same group of teachers to verify whether the implicit associations remained stable. This multisensory program was compared to a 12-week traditional teaching program with lecture classes held at IPEN for incoming post-graduation students. The multisensory program was effective for changing and maintaining the implicit associations of teachers towards the beneficial applications of nuclear technology, unlike the traditional teaching program with lecture classes. This work demonstrated that it is possible to break paradigms and prejudices. The multisensory program enabled an enriched knowledge about the applications of nuclear technology, that is, it promoted new experiences in the explicit memory, which modified the previous associations stored in the implicit memory. Therefore, the multisensory program has proven to be a successful, cost-effective tool, which is able to cause and maintain changes in implicit associations and can be applied in several areas where changes in implicit associations and prejudice reversal are desired. The results demonstrated that the proposed doctoral research was effective, thus contributing to the diffusion of knowledge of the beneficial applications of nuclear technology and, consequently, to its demythification. This methodology may be administered to other fields to identify, modify and/or reduce implicit prejudices or stereotypes.

The objectives of this dissertation were to find a principal domain of promising and technologically feasible reactor physics characteristics for a multi-purpose, modular-sized, lead-cooled, fast neutron spectrum reactor fueled with an advanced uranium-transuranic-nitride fuel and to determine the principal limitations for the design of an autonomous long-term multi-purpose fast reactor (ALM-FR) within the principal reactor physics characteristic domain. The objectives were accomplished by producing a conceptual design for an ALM-FR and by analysis of the potential ALM-FR performance characteristics. The ALM-FR design developed in this dissertation is based on the concept of a secure transportable autonomous reactor for hydrogen production (STAR-H2) and represents further refinement of the STAR-H2 concept towards an economical, proliferation-resistant, sustainable, multi-purpose nuclear energy system. The development of the ALM-FR design has been performed considering this reactor within the frame of the concept of a self-consistent nuclear energy system (SCNES) that satisfies virtually all of the requirements for future nuclear energy systems: efficient energy production, safety, self-feeding, non-proliferation, and radionuclide burning. The analysis takes into consideration a wide range of reactor design aspects including selection of technologically feasible fuels and structural materials, core configuration optimization, dynamics and safety of long-term operation on one fuel loading, and nuclear material non-proliferation. Plutonium and higher actinides are considered as essential components of an advanced fuel that maintains long-term operation. Flexibility of the ALM-FR with respect to fuel compositions is demonstrated acknowledging the principal limitations of the long-term burning of plutonium and higher actinides. To ensure consistency and accuracy, the modeling has been performed using state-of-the-art computer codes developed at Argonne National Laboratory. As a result of the computational analysis performed in this work, the ALM-FR design provides for the possibility of continuous operation during about 40 years on one fuel loading containing mixture of depleted uranium with plutonium and higher actinides. All reactor physics characteristics of the ALM-FR are kept within technological limits ensuring safety of ultra-long autonomous operation. The results obtained provide for identification of physical features of the ALM-FR that significantly influence flexibility of the design and its applications. The special emphasis is given to existing limitations on the utilization of higher actinides as a fuel component.