Made available in DSpace on 2014-10-09T12:29:01Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:14Z (GMT). No. of bitstreams: 1 01010.pdf: 16336682 bytes, checksum: fb7f780f24753f31fb96810fce4c3a14 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:35:33Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:01Z (GMT). No. of bitstreams: 0 / As normas de gestão ambiental têm por objetivo prover as organizações dos elementos necessários para implantação de Sistemas da Gestão Ambiental (SGA) que possam ser integrados a outros requisitos da gestão, e auxiliá-las a alcançar seus objetivos ambientais e econômicos. A Unidade de Produção de Hexafluoreto de Urânio USEXA, do Centro Tecnológico da Marinha em São Paulo - CTMSP, será a primeira planta industrial da etapa de conversão do ciclo do combustível nuclear (produção de hexafluoreto de urânio UF6) do Brasil, permitindo que seja agregado valor ao minério de urânio. Neste trabalho, o SGA proposto para a USEXA, permite disciplinar suas interfaces com o meio ambiente, uma vez que as Normas da CNEN Comissão Nacional de Energia Nuclear e da AIEA Agência Internacional de Energia Atômica para instalações nucleares, na sua grande maioria, visam a atender a critérios de segurança para o público e o meio ambiente, apenas nos quesitos envolvendo radiações ionizantes. O modelo de SGA desenvolvido preenche as lacunas das normas da CNEN e da AIEA, por considerar os impactos ambientais decorrentes do uso de substâncias químicas no processo de fabricação de UF6 e os aspectos gerais de sustentabilidade. Isso pode ser considerado uma contribuição original dentro das complexas atividades que abrangem o processamento de urânio no ciclo do combustível nuclear. Como resultado, esta pesquisa propõe, para avaliação de impactos ambientais, a adoção de um filtro de significância, relacionado à localização do empreendimento, apresenta um Manual do Sistema de Gestão para a USEXA e sugere modelos de treinamentos em gestão de pessoal, como o coaching e a programação neurolinguística, e que poderão ser aplicados em qualquer Sistema de Gestão. Os treinamentos podem ser considerados como uma ação preventiva, por contribuírem para diminuir os incidentes relacionados à manutenção de equipamentos e consequentemente a ocorrência de impactos ambientais. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:55:29Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:54Z (GMT). No. of bitstreams: 0 / O Instituto de Pesquisas Energéticas e Nucleares (IPEN) é uma Instituição de Pesquisas e Desenvolvimento que está localizada dentro de uma área densamente povoada, na cidade de São Paulo. O ciclo do combustível nuclear foi desenvolvido desde o yellow cake até o enriquecimento dentro do IPEN. Após esta etapa, toda técnica foi repassada à iniciativa privada e à Marinha do Brasil (CTM/SP). Algumas usinas do ciclo do combustível estavam em nível semi-industrial, com produção de mais de 20 kg.h-1. Como Instituto de Pesquisa, o IPEN cumpriu sua função no ciclo de combustível, que é desenvolver e repassar a tecnologia. Com a necessidade de se encontrar um lugar para implantar novos projetos, o espaço físico escolhido foi no local onde se achava a Usina de Produção de Hexafloreto de Urânio (UF6), que estava inativa há alguns anos e apresentava riscos de vazamento em potencial, o que poderia ocasionar agressão ao meio ambiente e riscos de acidentes graves. O descomissionamento desta usina exigiu um cuidadoso planejamento por ser um trabalho nunca realizado no Brasil, numa unidade desse tipo com riscos eminentes, visto que envolvia o gás fluoridetro (HF) e ácido fluorídrico, solução altamente corrosiva. Fizeram-se avaliações criteriosas e desenvolveram-se equipamentos especiais, com o intuito de evitar vazamentos e riscos de acidente. No trabalho de descomissionamento, foram obedecidas as normas da CNEN em todas as operações realizadas. Foi calculado o impacto ambiental, que se mostrou desprezível sendo que as doses de radiação, após o térmíno do trabalho, estavam dentro dos limites de público, podendo a área ser liberada para nova utilização. O tipo de descomissionamento realizado foi de remoção completa, retirando-se todos os materiais e equipamentos. Todos os rejeitos foram tratados e/ou armazenados em instalações adequadas. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Minimization of HLW inventories and U consumption are key elements guaranteeing nuclear energy expansion. The integration of complex nuclear systems into a viable cycle yet constitutes a challenging multi-parametric optimization problem. The reactors and fuel cycle performance parameters may be strongly dependent on minor variations in the system's input data. Proven discrepancies in nuclear data evaluations could affect the validity of the system optimization metrics. This study first analyzes various advanced AP1000-VHTR fuel cycle scenarios by assessing their TRU destruction and their U consumption minimization capabilities, and by computing reactor performance parameters such as the time evolution of the effective multiplication factor keff, the reactors' energy spectrum or the isotopic composition/activity at EOL. The performance metrics dependence to prompt neutron fission spectrum discrepancies is then quantified to assess the viability of one strategy. Fission spectrum evaluations are indeed intensively used in reactors' calculations. Discrepancies higher than 10% have been computed among nuclear data libraries for energies above 8MeV for 235U. TRU arising from a 3wt% 235U-enriched UO2-fueled AP1000 were incinerated in a VHTR. Fuels consisting of 20%, 40% and 100% of TRU completed by UO2 were examined. MCNPX results indicate that up to 88.9% of the TRU initially present in a VHTR fueled with 20% of TRU and 80% of ThO2 were transmuted. Additionally, the use of WgPu instead of RgPu should reduce the daily consumption of 235U by 1.3 and augment core lifetime. To estimate the system metrics dependence to fission spectrum discrepancies and validate optimization studies outputs, the VTHR 235U fission spectrum distribution was altered successively in three manners. keff is at worst lowered by 1.7% of the reference value and the energy spectrum by 5% between 50meV and 2MeV when a significantly distorted fission spectrum tail is used. 233U, 236Pu and 237Pu inventories and activities are multiplied by 263, 523 and 34 but are still negligible compared to 239Pu mass or the total activity. The AP1000-VHTR system is in conclusion not dependent on the selected fission spectrum variations. TRU elimination optimization studies in AP1000-VHTR systems will be facilitated by freeing performance metrics dependency from 1 input parameter.

This work considers the impact of fast reactor fuel cycles on the UK's nuclear waste inventory, focusing on the disposition of the UK's plutonium stockpile and spent fuel from new build nuclear reactors. Reprocessing spent fuel from nuclear reactors has led to a large stockpile of civil plutonium in the UK. At the end of reprocessing the stockpile was estimated to be 112 tonnes. This large stockpile of separated plutonium poses a proliferation concern and there is no strategy at present for UK plutonium disposition. The NDA's position paper in 2014 stated the re-use of plutonium in a reactor as a preferred option. These options included Mixed OXide (MOX) fuelled Pressurised Water Reactors (PWR) and the use of plutonium in a Sodium-cooled Fast Reactor (SFR), PRISM, operated as a once-through plutonium burning fast reactor. As yet a preferred option has not been selected by the government. Nuclear power is the UK's largest source of low-carbon electricity. Current plans aim to build 16 GWe of new reactors by 2050 to replace the UK's current fleet. This work considered PWR MOX and once-through SFRs for UK plutonium disposition, comparing their relative merits to the direct disposal of the plutonium stockpile in a geological repository. The waste performance of disposition options were compared using assessment criteria based on: Technology Readiness Level (TRL), final stockpile mass, repository size and radiotoxicity. To maximise the reduction of the UK's plutonium stockpile, closed SFR fuel cycles were also considered with scenarios aimed at improving waste performance. Once-through and closed SFR fuel cycles were also considered for the disposition of spent fuel from new build reactors. Research presented in this thesis shows that UK waste disposition options are highly dependent on fuel cycle operating parameters. In once-through plutonium disposition options all scenarios increased repository size compared to direct disposal. Once-though SFRs increased repository size the least, where as PWR MOX reduced the stockpile mass most significantly. The most significant improvement in waste performance, using a closed fuel cycle up to 2150, required short reprocessing times and americium reprocessing. There were no additional improvements of significance with curium reprocessing and the choice of metallic or MOX fuelled SFRs had little impact on waste performance. Preferred fuel cycle scenarios are dependent on the priority given to different assessment criteria. To compare fuel cycle scenarios on an even basis, decision analysis methods were presented using assessment criteria results from the fuel cycles modelled in this work. Decision analysis methods were designed so that the reader can apply their own priorities, through the use of weightings, to the assessment criteria to determine preferable fuel cycle scenarios.

In recent years, the multilateral approach to the nuclear fuel cycle has been promoted as a potential mechanism for strengthening the nuclear non-proliferation regime. The multilateral approach has the potential to gain international favour over what has become traditional practice – the indigenous development and control of nuclear facilities. This thesis explores the way in which four states have responded to the revived attention on multilateral approaches to the nuclear fuel cycle, within the framework of the norm life cycle. The varying levels of support reflect broader international opinion on this issue, as many developing states remain concerned that they may be required to forgo not only the “inalienable right” to peaceful nuclear energy, but also the prospective economic and technological benefits of indigenous development in order to participate. However, as the risk of further proliferation and nuclear terrorism comes to the fore of international agendas, facilitating multilateral control of the most sensitive aspects of peaceful nuclear energy may be the key to strengthening the non-proliferation regime in the 21st century.

The SABR fusion-fission hybrid concept for a fast burner reactor, which combines the IFR-PRISM fast reactor technology and the ITER tokamak physics and fusion technology, is adapted for a fusion-fission hybrid reactor, designated SABrR. SABrR is a sodium-cooled 3000 MWth reactor fueled with U-Pu-10Zr. For the chosen fuel and core geometry, two configurations of neutron reflector and tritium breeding structures are investigated: one which emphasizes a high tritium production rate and the other which emphasizes a high fissile production rate. Neutronics calculations are performed using the ERANOS 2.0 code package, which was developed in order to model the Phenix and SuperPhenix reactors. Both configurations are capable of producing fissile breeding ratios of about 1.3 while producing enough tritium to remain tritium-self-sufficient throughout the burnup cycle; in addition, the major factors which limit metal fuel residence time, fuel burnup and radiation damage to the cladding material, are modest.

The final disposal location for used nuclear fuel in the U.S. remains unresolved. A major complication in resolving this issue has historically been the lack of public acceptance. This motivates the creation of a decision making model for selecting a nuclear fuel cycle in the U.S. that incorporates the preferences of the public. A model based on the Analytic Hierarchy Process (AHP) was created, tested, and shown to be problematic in incorporating public opinion into decision objectives. A new model based on Multi-Attribute Utility Theory (MAUT) has been created. This model contains the fundamental objectives for both technical and non-technical factors in both the short and long term for the decision. Additionally, the relevant subject matter experts involved in a nuclear fuel cycle selection are evaluated based on the public's perception of their qualifications, and environmental scientists are found to be considered equally as qualified as nuclear engineers and scientists.

O Brasil com o propósito de se tornar autossuficiente na produção de radioisótopos e fontes radioativas usados na medicina nuclear, na agricultura e no meio ambiente desenvolveu o projeto de um reator multipropósito de 30 megawatts de potência para atender a demanda nacional. No Instituto de Pesquisas Energéticas e Nucleares (IPEN), o Centro de Combustível Nuclear (CCN) é responsável pela fabricação dos combustíveis para o reator IEA-R1 e, possivelmente, pelos combustíveis do reator multipropósito. Com o intuito de atender a demanda para os reatores foi projetada uma nova planta de fabricação com a capacidade máxima de 60 combustíveis por ano, o qual atualmente é de dez. O aumento da produção consequentemente aumentará o volume de efluentes gerados. A atual preocupação com o meio ambiente faz-se necessário elaborar um plano de gestão para tornar o processo sustentável, o qual ocasionará em benefícios ambientais, econômicos e sociais. O processo produtivo do combustível gera vários tipos de efluentes, contendo urânio ou não, sendo sólidos, líquidos e gasosos com características físicas e químicas variadas. Esse estudo tem como objetivo identificar, caracterizar e segregar os efluentes gerados em todo o processo produtivo de obtenção do combustível nuclear do tipo MTR (Materials Testing Reactors). No desenvolvimento do presente trabalho foram utilizadas como base a Resolução n° 357, de 17 de março 2005, e a Resolução n° 430, de 13 de maio de 2011 do Conselho Nacional do Meio Ambiente CONAMA. Com os resultados obtidos foi possível determinar que os efluentes líquidos são os principais aspectos que podem causar contaminação ao meio ambiente, e a atual situação do CCN mostra que 30% do efluente líquido possui tratamento de recuperação de urânio; 20% dos efluentes líquidos são reutilizados na composição química em que foi gerado; 35% descartado diretamente ao meio ambiente de acordo com a legislação. O restante dos efluentes líquidos, cerca de 15%, estão em fase de desenvolvimento do processo de tratamento. / Brazil with the purpose of becoming self-sufficient in the production of radioisotopes and radioactive sources used in nuclear medicine, agriculture and the environment has developed the project of a multipurpose reactor of 30 megawatts of power to meet the national demand. At the Instituto de Pesquisas Energéticas e Nucleares (IPEN), the Centro de Combustível Nuclear (CCN) is responsible for manufacturing fuels for the IEA-R1 reactor and, possibly, the multipurpose reactor fuels. In order to meet the demand for the reactors, a new manufacturing plant with a maximum capacity of 60 fuels per year has been designed, which is currently ten. The increase in production will consequently increase the volume of effluents generated. The current concern with the environment makes it necessary to elaborate a management plan to make the process sustainable, which will lead to environmental, economic and social benefits. The production process of the fuel generates several types of effluents - containing uranium or not - being solid, liquid and gaseous with varied physical and chemical characteristics. This study aims to identify, characterize and segregate the effluents generated in the entire production process of obtaining the nuclear fuel type MTR (Materials Testing Reactors). In the development of this paper, Resolution 357 of March 17, 2005, and Resolution No. 430 of May 13, 2011 of the National Environmental Council - CONAMA, were used. With the results obtained it was possible to determine that the liquid effluents are the main aspects that can cause contamination to the environment, and the current situation of the CCN shows that 30% of the liquid effluent has uranium recovery treatment; 20% of the liquid effluents are reused in the chemical composition in which it was generated; 35% discarded directly to the environment according to the legislation. The rest of the liquid effluents, about 15%, are in the development phase of the treatment process.

Os acidentes causados pelo efeito dominó são dos mais graves ocorridos na indústria química e de processo. Mesmo sendo o potencial destrutivo desses eventos acidentais bastante conhecido, pouca atenção tem sido dada a este problema pela literatura técnica e uma metodologia completa e aprovada para a avaliação quantitativa da contribuição do efeito dominó ao risco industrial ainda não está plenamente desenvolvida. O presente estudo propõe um procedimento sistemático para a avaliação quantitativa do efeito dominó em plantas químicas do ciclo do combustível nuclear. O trabalho é baseado em avanços recentes feitos na modelagem de danos a equipamentos de processo causados por incêndios e explosões devido aos vetores de propagação (radiação de calor, sobrepressão e projeção de fragmentos). Dados disponíveis na literatura técnica e novos modelos de vulnerabilidade deduzidos para diversas categorias de equipamentos de processo foram utilizados no presente trabalho. O procedimento proposto é aplicado a uma área de tancagem típica de uma planta de reconversão situada em um sítio que abriga varias outras instalações do ciclo do combustível nuclear. São analisados os vários eventos iniciadores, seus vetores de propagação, as conseqüências desses eventos e as freqüências associadas ao efeito dominó. / Accidents caused by domino effect are among the most severe accidents in the chemical and process industry. Although the destructive potential of these accidental scenarios is widely known, little attention has been paid to this problem in the technical literature and a complete methodology for quantitative assessment of domino accidents contribution to industrial risk is still lacking. The present study proposed a systematic procedure for the quantitative assessment of the risk caused by domino effect in chemical plants that are part of nuclear fuel cycle plants. This work is based on recent advances in the modeling of fire and explosion damage to process equipment due to different escalation vectors (heat radiation, overpressure and fragment projection). Available data from literature and specific vulnerability models derived for several categories of process equipment had been used in the present work. The proposed procedure is applied to a typical storage area of a reconversion plant situated in a complex that shelters other nuclear fuel cycle facilities. The top-events and escalation vectors are identified, their consequences estimated and credible domino scenarios selected on the basis of their frequencies.