The purpose of the work described in this thesis was to explore the use of fractional crystallization as a technology that can be used to separate medium-curie waste from the Hanford Site tank farms into a high-curie waste stream, which can be sent to a Waste Treatment and Immobilization Plant (WTP), and a low-curie waste stream, which can be sent to Bulk Vitrification. The successful semi-batch crystallization of sodium salts from two single shell tank simulant solutions (SST Early Feed, SST Late Feed) demonstrated that the recovered crystalline product met the purity requirement for exclusion of cesium, sodium recovery in the crystalline product and the requirement on the sulfate-to-sodium molar ratio in the stream to be diverted to the WTP. In this thesis, experimental apparatus, procedures and results are given on scaled-down experiments of SST Early Feed for hot-cell adaptation along with operating parameters and crystallization mechanism studies on early feed multi-solute crystallization. Moreover, guidance is given regarding future steps towards adapting the technology to multi-salt crystallization kinetic parameter estimates and modeling. Crystallization, Evaporative Fractional Crystallization, Nuclear Waste Pretreatment, Cesium Removal, Hanford, SST Early and Late feed, Multi-solute, Multi-salts, Simulant Testing

In the ternary system CsCl – NaCl – H2O, at a temperature of 298.15 K, a double salt with the stoichiometric formula CsCl∙2NaCl∙2H2O(cr) is known to be formed. This double salt and the anhydrous CsCl(cr) are the end-members of a solid solution. For the pure double salt, the solubility constant was determined. The obtained value was applied to calculate the solubility diagram also of the quaternary system CsCl – NaCl – KCl – H2O and the quaternary-reciprocal system Cs+, Na+ || Cl−, SO42− – H2O. The solubility constant together with a solid solution between CsCl·2NaCl·2H2O(cr) and CsCl(cr) were implemented in THEREDA, which extends the applicability of the existing cesium dataset.

No description available.

Apresentamos os aspectos mais relevantes para se realizar um chafariz a átomos frios de 133Cs, para operá-lo como um padrão primário de tempo e freqüência para realizar a definição do segundo. O objetivo principal desse trabalho foi a otimização do sistema experimental do chafariz de átomos em duas partes críticas: a região de interação e o sistema de detecção. Além disso, otimizamos as diversas fases da manipulação óptica que fazem parte do ciclo de operação de um chafariz com o intuito de aumentar a relação sinal ruído na região de detecção. Quando os átomos são lançados com uma velocidade de 3,39ms-1, atingem o ápice a 60cm acima da região de captura e passam 360ms na região de vôo livre. A temperatura dos átomos na região de detecção não ultrapassa 15,5K e a diferença de população observada através das Franjas de Ramsey, que são a assinatura característica de um padrão de freqüência atômico, tem a largura a meia altura de 1,4Hz. A largura de linha e a relação sinal ruído da franja implicam em uma estabilidade a curto prazo de 5,18×1012. Alguns causadores de deslocamentos de freqüência como a radiação de corpo negro, o efeito Doppler de segunda ordem, o efeito gravitacional e o efeito Zeeman de segunda ordem foram avaliados. / We present some relevant aspects for the realization of a 133Cs fountain, intended to operate as a primary frequency standard to realize the definition of the second. The main goal of this work is the optimization of the experimental setup of the atomic fountain in its most critical parts: the interaction region and the detection system. Furthermore, the several phases of the optical manipulation which concern the operation cycle of an atomic fountain were also optimized. These procedures allowed us to increase the signal to noise ratio in the detection signal. When the launching velocity is about 3.39 m/s, the atoms reach the apogee about 60 cm above the capture region and spend 360 ms in the free flight zone. The atomic ensemble temperature in the detection region is about 15.5K and the population difference between the two fundamental level is measured through the Ramsey fringe with a linewidth of 1.4 Hz. This linewidth, allied to the obtained S/N resulted in the measured short-term stability of 5.18×1012. Some frequency shift as the black body radiation shift, gravitational shift, second order Doppler shift and second order Zeeman shift were measured.

Large-scale radiological accidents have resulted in intakes of radioactive materials by members of the public and occupational radiation workers. However, current methods to evaluate intakes are designed for small numbers of individuals and cannot be easily scaled for large populations as has occurred. A proposed method for high throughput volumes of people to identify and quantify intakes of radioactive material through urine radiobioassay is described. MATERIALS AND METHODS: The MCNP V6.0 software code was used to model the General Electric Hawkeye V3 Gamma Camera for gamma ray efficiency. Technitium-99m was used to validate the model. The model was used to calculate detection efficiencies and minimum detectable doses for Cobalt-60, Iodine-131, Cesium-137/Barium-137m and Iridium-192. RESULTS: Differences of 8% were observed between measurements of the detection efficiency for Technitium-99m and the MCNP modeled detection efficiency (11.1% vs. 12.0%, respectively). Calculations showed that a dose of 20 mSv could be detected using urine radiobioassay in 6, 3, 2, and 20 days post incident for Type F intakes of Cobalt-60, Iodine-131, Cesium-137/Barium-137m and Iridium-192 respectively. Approximately 1,152 urine samples could be analyzed in an eight-hour shift using a single gamma camera. CONCLUSIONS: The use of the gamma camera for urine radiobioassay allows for high throughput volumes of samples and has sufficient detection sensitivity to meet dose-based decision guidelines.

Em 1967, a definição do segundo passou a ser baseada nas propriedades atômicas dos átomos de 133Cs. O instrumento utilizado para reproduzir esta definição é um relógio atômico. Neste trabalho iremos apresentar os progressos feitos no programa brasileiro de metrologia científica de tempo e freqüência. A proposta deste trabalho de dissertação é a caracterização do nosso padrão. Nós estudaremos os deslocamentos presentes em um relógio atômico, como o efeito Zeeman Quadrático, Δ ν/ ν0 =5,4×10-13 o ?Cavity Pulling?, Δ ν/ ν0 = 1,27×10-13 e o ?Rabi Pulling?, Δν/ν0 =1,3×10?13 entre outros, que são induzidas na freqüência hiperfina do césio. Os resultados obtidos neste trabalho podem ser resumidos da seguinte forma: uma incerteza global de 1,44×10-12 e uma estabilidade a curto prazo dada pela raíz quadrada da variância de Allan 1,8×10-10Τ-0,5. Estes resultados foram medidos após as seguintes mudanças efetuadas em nosso padrão: determinamos a potência ótima injetada na cavidade afim de aumentar o sinal e assegurar que os átomos sofram uma transição π/2; melhoramos o controle do campo magnético estático aplicado ao longo da cavidade de interrogação resultando em um campo magnético mais homogêneo; e, diminuímos a temperatura de operação do forno do relógio tal que a velocidade média dos átomos presente no feixo atômico diminui significativamente. Todas estas mudanças resultaram no ganho de uma ordem de grandeza na acuracia e na estabilidade de nosso relógio. / Since 1967, the definition of the second is based on the atomic properties of the 133Cs atom. The device that realises this definition is an atomic clock. In this work, we present the progress made in the last year on Brazilian scientific time and frequency program. The aim of this dissertation work is the caracterization of our standard. We report the major sifts present in our atomic clock due to Quadratic Zeeman effect, Δν/ν0 =5,4×10-13 Cavity Pulling, Δν/ν0 =1,27×10-13 Rabi Pulling, Δν/ν0 =1,3×10-13 and other ones, which induced a shift in the hiperfine levels frequency of the performances: a global uncertainty of 1,44×10-12 and a short term stability of 1,8×10-10Τ-0,5 .The results were obtained after these changes: we have determined the optimum microwave power injected into the cavity in order to increase the signal and assure that the atoms suffer a π/2 pulse; we have also minimizes the field inhomogeneity by improving the control of the static magntic field along the interaction region; we have decreased the temperature of the clock oven in order to obtain a slower atomic beam. All this changes has increased our accuracy and our stability of about one order.

Made available in DSpace on 2016-08-10T10:39:19Z (GMT). No. of bitstreams: 1 BRAULIO CANCADO FLORES.pdf: 638020 bytes, checksum: 0d45d0c26c601b5579ff1ec8f22426fc (MD5) Previous issue date: 2008-06-27 / The most serious radiological accident occurred in the western hemisphere and it happened in September of 1987, when a radiotherapy unit containing 50.9 TBq of Cs137Cl was removed from an abandoned radiotherapy clinic in the State of Goias, Brazil and it was subsequently disassembled. This event provides an opportunity to assess the genetic effects of ionizing radiation. We investigated the genetic variation of 12 microsatellite loci in 11 families of exposed liquidators, who worked at the civil defense procedures. As a control group, non-exposed families, comprised of 900 individuals, from the same area of Goias state were analyzed. When we compared the exposed and control groups, we found an increase in the number of new alleles in the offspring of the exposed liquidators. The mutation rate was found to be higher in the exposed families compared to the control group. These results, associated with previous studies, indicated that exposure to ionizing radiation can be detected in offspring of exposed liquidators and also suggest that the elevated microsatellite mutation rate can be attributed to radioactive exposure. / O acidente radiológico mais grave do ocidente aconteceu em setembro de 1987, quando um aparelho de radioterapia contendo 50.9 TBq de Cs137Cl foi removida das ruínas de uma clínica de radioterapia e em seguida, violada. Este acontecimento criou a oportunidade de que se investigasse os efeitos genéticos da radiação ionizante. Foi investigada a variabilidade genética em 12 loci microssatélites em 11 famílias de liquidators, que trabalharam nas ações de defesa civil. Como grupo controle, utilizamos famílias sem potencial de exposição à radiação ionizante, perfazendo 900 indivíduos analisados, da mesma área do Estado de Goiás. Quando comparamos os grupos exposto e controle, encontramos um incremento no número de novos alelos nos perfis dos liquidators expostos. A taxa de mutação encontrada foi maior nas famílias dos expostos do que no grupo controle. Estes resultados, associados a anteriores, indicaram que a análise dos perfis alélicos dos liquidators pode indicar a exposição à radiação ionizante, além de uma elevada taxa de mutações de microssatélites poder ser atribuída a esta exposição

Made available in DSpace on 2016-08-10T10:47:31Z (GMT). No. of bitstreams: 1 JOAO LUIS FELIX DE SOUSA BUFAICAL.pdf: 2034693 bytes, checksum: 90a6234a62487ab0c3fdd519f03eb107 (MD5) Previous issue date: 2012-12-18 / The problems related to social communication and lack of information caused a great degree of panic and confusion on the citizen s mind, specially considering that it was a completely new and extraordinary event, for which people were not logistically or psychologically prepared to deal with. The sensationalist press - which only increased fear, prejudice and suspicion - contributed to disseminate malinformation and cause more turmoil and social convulsion. The country as a whole was not prepared to deal with those tragic facts, and probably it would not be today if something of that magnificence happened to occur again. / Os problemas relacionados à comunicação social e à desinformação causaram um grande pânico ao cidadão goianiense (goiano, e até brasileiro), especialmente considerando que foi um evento completamente novo e extraordinário, para o qual as pessoas não estavam logística e psicologicamente preparadas (para lidar). A imprensa, que por vezes agiu de maneira sensacionalista, acabou contribuindo para aumentar ainda mais o medo, o preconceito e a desconfiança, ao disseminar informações truncadas e até mesmo incorretas, causando ainda mais tumulto e convulsão social. O país como um todo não estava preparado para lidar com esses fatos trágicos - e provavelmente não estaria preparado hoje, se algo dessa magnitude voltasse a ocorrer.

Apresentamos os aspectos mais relevantes para a construção e caracterização de um padrão primário de tempo e frequência compacto. Nesse sistema a amostra de átomos de referência é preparada a partir de uma armadilha magneto-óptica. Após a obtenção de uma amostra significativa de átomos os feixes laser são desligados e, durante a expansão livre, a nuvem atômica é submetida a uma sequência de pulsos de micro-ondas que caracterizam o método de Ramsey. Os pulsos de micro-ondas são aplicados em uma cavidade de micro-ondas, esculpida dentro da câmara de vácuo. Todo o ciclo de funcionamento é implementado dentro dessa cavidade e por esse motivo o padrão é considerado compacto. Quando os átomos são interrogados com pulsos de τ = 1 ms separados por Τ = 8 ms obtemos uma largura a meia altura da franja central de 52 Hz e uma estabilidade a curto prazo de 10-13. Alguns causadores de deslocamentos de frequência foram avaliados. / We present some relevant aspects for the construction and characterization of a compact primary frequency standard. In this system, the atomic ensemble is prepared with a magnetooptical trap. Once a significant number of cold atoms is obtained, the laser beams are turned off and, during the free expansion, the cloud is submitted to a sequence of two microwave pulses, characterizing the well-known Ramsey method. The microwave pulses are applied in a microwave cavity that was sculpted inside the vacuum chamber. All the working cycle takes place into this cavity. When the atoms are interrogated by two pulses of τ = 1 ms separated by Τ = 8 ms, the linewidth of the central fringe is 52 Hz and a short-term stability 10-13 is observed. Some frequency shifts were evaluated.

Suite aux accidents nucléaires de Tchernobyl (1986) ou Fukushima (2011), de grandes quantités de radioéléments ont été disséminées dans l’environnement. Parmi ces derniers, le césium 137 est le radionucléide le plus abondant et constitue la principale source d’exposition des populations avoisinantes sur le long terme, notamment par son intégration dans la chaîne alimentaire. Ce sont quelques milliers de becquerels qui sont quotidiennement ainsi ingérés. Un important questionnement concerne donc les effets potentiels que peuvent induire une telle exposition sur les fonctions physiologiques.Concernant le système cardiovasculaire, il existe une corrélation entre la dose d’exposition et la fréquence d’apparition de pathologies cardiovasculaires. Cependant, lorsqu’il s’agit d’une exposition à faibles doses, comme en cas de situations post-accidentelles, les études ne sont pas toutes en accord, dû au caractère multifactoriel de ces maladies, une grande prudence est nécessaire quant à l’interprétation des données épidémiologiques. Ainsi, ce travail de thèse vise à compléter les études épidémiologiques disponibles suivant une exposition interne à faibles doses de césium 137, et plus particulièrement dans le cadre de la pathologie athéromateuse. En effet, l’athérosclérose est reconnue comme étant la 1ère cause de mortalité/morbidité dans les pays industrialisés. Des animaux prédisposés à la pathologie (souris ApoE-/-), ont été exposés à des concentrations de césium de 4 à 100 kBq.L-1 pendant 3, 6 ou 9 mois.Ainsi, au bout de 3 mois d’exposition, les animaux ayant reçu la plus forte concentration présentent une augmentation de certains paramètres inflammatoires, notamment IFN-γ et VCAM-1, ainsi qu’une augmentation de l’épaisseur média-intima comparé aux animaux témoins. De plus, nous avons noté des variations concomitantes de l’expression d’enzymes pro/anti oxydantes (p47, p67, GPx). Ces observations ne perdurent pas au fil du temps. En effet, après 6 et 9 mois d’exposition, les plaques d’athérome qui se sont formées présentent des caractéristiques de stabilité plus importantes que les animaux témoins, avec des paramètres pro-inflammatoires (CRP, TNF-α, MCP-1 et IFN-γ) diminués, une augmentation du contenu en collagène, ainsi qu’une baisse de l’expression de certaines collagénases.L’ensemble de ces résultats suggèrent qu’une exposition interne chronique à faibles doses de césium 137 ne potentialise pas la pathologie athéromateuse dans notre modèle expérimental. Une telle exposition induit la mise en place d’une réponse adaptative au cours du temps, allant en faveur d’une amélioration du phénotype des plaques d’athérome, en agissant sur la balance des cytokines pro/anti inflammatoires, ainsi qu’une modulation du système anti-oxydant. / Large amounts of radionuclides were released in the environment after the Chernobyl (1986) or Fukushima-Daichii (2011) nuclear accidents, and mostly cesium 137. Populations living in contaminated territories are chronically exposed to radionuclides by ingestion of contaminated food. There is a real interrogation about the potential effects that could be induced following such ionizing exposure on physiological functions in the long term.Concerning the cardiovascular system, there is a correlation between the irradiation dose and the appearance of cardiovascular diseases. However, when we focused on post-accidental situations, with a low dose exposure, available data are not all in accordance, due to multifactorial aspect of these pathologies. Epidemiological results should be interpreted carefully.Thus, the aim of my thesis is to complete epidemiological studies about chronic internal γ low dose exposure, using cesium 137, in an atheromatous context. Atherosclerosis and its consequences are known to be the main cause of mortality/morbidity in industrialized countries.Predisposed animals (ApoE-/- mice) were exposed to 137Cs through the drinking water. The concentration range was 4 to 100 kBq.L-1, to surround concentration found in contaminated territories around Chernobyl. Exposure times were 3, 6 or 9 months to follow atherosclerosis progression.After 3 months exposure, for the early stages, mice exposed to the highest dose presented an increase in some inflammatory cytokines, notably IFN-γ and VCAM-1, with an intimal-medial thickness increased compared to non-exposed animals. Moreover, at this time exposure, we noticed concomitant variation of genic expression of pro and anti-oxydative enzymes (p47, p67, GPx). These effects are only transient and do not perdure over the time. Indeed, after 6 and 9 months exposure, atheromatous plaque observed in the aortic sinus, present more stability parameters than the control group (collagen), with also a decrease in pro-inflammatory profile cytokines expression (CRP, TNF-α, MCP-1 et IFN-γ), and MMPs expression, and increase in GPx activity compared to the control group.All together, these results suggest that chronic internal exposure to low dose ionizing radition with 137Cs do not potentiate atherosclerosis progression. Such exposure induces an adaptive response along the experimental process, with an amelioration of atheromatous plaque phenotype, acting on the balance of pro/anti-inflammatory cytokines, pro/anti oxydant system.