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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Reprocessamento de cateteres de angiografia cardiovascular após uso clínico e contaminados artificialmente: avaliação da eficácia da limpeza e da esterilização. / Reprocessing of cardiovascular angiography catheter after clinical use and artificial soil: evaluation of the efficaccy of the cleaning and sterilization.

Ribeiro, Silma Maria Cunha Pinheiro 22 May 2006 (has links)
A prática assistencial na área da saúde implica situações de risco, os quais podem ser maximizados, minimizados ou projetados no julgamento à luz da fundamentação científica. O reprocessamento de materiais de uso único é uma prática que, a cada dia, tem exigido esforços dos profissionais de saúde no sentido de buscar e produzir evidências que auxiliem no processo de tomada de decisão em relação à não-realização ou sob que condições podem ser executadas. O objetivo geral deste estudo foi avaliar a aplicação de diferentes processos de limpeza e a esterilização em óxido de etileno a 100% nos cateteres de angiografia cardiovascular com vista à determinação da capacidade de redução da carga microbiana e do resíduo orgânico neles antes e após a utilização pelo paciente, assim como em situações de simulação com testes desafio. Trata-se de pesquisa experimental, aplicada, comparativa e controlada realizado no Research Centre do Saint Boniface General Hospital filiado à University of Manitoba, localizada em Winnipeg no Canadá. Os cateteres foram utilizados uma única vez por pacientes submetidos a angiografia coronariana e à análise de resíduos orgânicos (hemoglobina, carboidrato, proteína e endotoxina) por meio de testes bioquímicos diretos e indiretos utilizando a técnica de espectrofotometria. A carga microbiana foi avaliada por meio da realização de cultura microbiológica por método indireto. Esses experimentos foram realizados em quatro etapas, sendo a primeira imediatamente após o uso dos cateteres para determinação da sujidade basal; a segunda, após o uso pelo paciente e limpeza do cateter por diferentes métodos; a terceira, após o uso pelo paciente, de inoculação de sujidade artificial e limpeza por diferentes métodos e a quarta, após o uso pelo paciente, teste desafio, limpeza e esterilização simulando-se cinco reusos. Foram utilizadas técnicas de estatística descritiva e analítica por meio de testes estatísticos paramétricos (análise de variância) e, quando necessário, testes não paramétricos (Kruskall-Wallis). Em todas as análises estatísticas, foram considerados testes bilaterais com um nível de significância estatística de 5% ou 0,05 e o intervalo de confiança estabelecido foi de 95%. O resultado positivo em qualquer um dos testes de detecção de resíduo orgânico e microbiológico foi indicativo de ineficácia do método de limpeza testado. As unidades amostrais foram submetidas aos seguintes métodos de limpeza: limpeza manual com detergente enzimático com enxágüe em água de torneira ou água tratada com osmose reversa e esterilizada; limpeza manual com detergente contendo peróxido de hidrogênio com enxágüe com água tratada com osmose reversa e esterilizada; limpeza automatizada com detergente enzimático sem enxágüe ou com enxágüe em água tratada com osmose reversa e esterilizada; limpeza sob pressão contínua com detergente contendo peróxido de hidrogênio com enxágüe em água de torneira ou água tratada com osmose reversa e esterilizada. Os resultados obtidos neste estudo apontam para a manutenção da carga microbiana antes e após a limpeza dos cateteres. Antes da execução de qualquer método de limpeza dos cateteres, a freqüência de culturas positivas foi de 8,2%, com uma carga microbiana média de 500UFC/unidade. Após a limpeza dos cateteres a freqüência de culturas positivas foi de 8,3% e a carga microbiana média foi de 250UFC/unidade. Os resíduos orgânicos basais detectados nos cateteres apresentavam-se nas seguintes concentrações: 146,3 µg/unidade de hemoglobina, 628,5 µg/unidade de proteína e 7,0 µg/unidade de carboidrato e 38,0 UE/unidade de endotoxina. Após a realização de cinco simulações, a concentração de hemoglobina indireta foi abaixo do limite de detecção do teste, proteína indireta =107,7 µg/unidade, carboidrato indireto= 340,1µg/unidade e endotoxina=5,4UE/unidade. A análise da concentração dos resíduos orgânicos de acordo com os métodos de limpeza demonstrou diferentes níveis de redução. Os métodos de limpeza que utilizaram o detergente contendo peróxido de hidrogênio apresentaram melhor desempenho em relação aos que utilizaram detergentes enzimáticos, sendo que o do método de limpeza sob pressão contínua foi superior aos demais métodos. Os resultados dos resíduos orgânicos dos cateteres que foram submetidos a cinco simulações de reuso mostraram-se inferiores aos valores médios absolutos de uma única simulação, com exceção da concentração média de carboidrato. / The healthy assistance implies in risk, which can be maximized, minimized or projected based on the scientific data. The reprocessing of single used devices is a practice that each day has demanded efforts of the healthcare professionals in order to search and to produce scientific evidences to help them make decision in relation to not reuse or reuse under safety conditions. The objective of this study was to evaluate different cleaning processes and sterilization in ethylene oxide 100% of the angiographic catheters in order to determine the capacity in reducing of the bioburden and the organic residual before and after patient use, as well as in simulated use with soil test. It is an experimental research, comparative and controlled permed in the Research Centre of the Saint Boniface General Hospital affiliated to the University of Manitoba located in Winnipeg, Canada. The catheters had been used only one time for coronariographic exam and submitted to the analysis of organic residues (hemoglobin, carbohydrate, protein and endotoxin) by in situ and destructive test reading by spectrophotometer. The bioburden was evaluated by microbial culture. These experiments had been performed in four phases, being the first immediately after patient use to determine the basaline soil; the second after patient use and cleaning of the catheter by different methods; the third after patient use, soil test inoculation and cleaning by different methods. The fourth phase was performed after patient use and simulated reuse. Descriptive and analytical statistic analysis by parametric statistical tests (variance analysis) or no parametric tests (Kruskall-Wallis) were performed. Had been considered bilateral tests with a significance level < 0,05 and the confidence interval was 95%. It was considered clening failure of the cleaning process any positive results of the detention of organic and microbiological residue. The catheters were submitted to the following cleaning methods: manual washing with enzymatic detergent with tap water or reverse osmosis sterile rinsing; manual washing with hydrogen peroxide detergent rinsing in reverse osmosis sterile water, automated washing with no rinse or reverse osmose sterile water; hydrogen peroxide detergent pumping with tap water or reverse osmosis sterile rinsing . The results gotten in our study showed the maintenance of the bioburden before and after the cleaning of the catheters. In the baseline phase 8,2% of the cultures were positive cultures and the microbial load was 500CFU/device. After cleaning it was 8,3% and the average microbial load was 250 CFU/device. The baseline organic residues data were hemoglobin 146,3µg/device, protein 628,5 µg/device, carbohydrate 7,0µg/device and endotoxin 38,0EU/device. After five simulated use, the indirect hemoglobin concentration was lower of the test limit of detention, protein = 107,7 µg/device, carbohydrate = 340,1µg/device and endotoxin=5,4EU/device. The organic residual analysis according the cleaning methods found different levels of reduction. The cleaning methods that had used a hydrogen peroxide detergent showed better performance relating the enzymatic detergents methods, as well as hydrogen peroxide detergent pumping with reverse osmosis sterile rinsing was the best method. After simulated use phase the organic residue showed lower concentration, excepted the carbohydrate level.
112

ESTUDO DA DEGRADAÇÃO DE NANOCOMPÓSITOS DE POLIPROPILENO COM ARGILA MONTMORILONITA APÓS MÚLTIPLOS REPROCESSOS

Silvano, Josiane da Rocha 30 July 2012 (has links)
Made available in DSpace on 2017-07-21T20:42:37Z (GMT). No. of bitstreams: 1 Josiane Silvano.pdf: 1614432 bytes, checksum: 60d9480513d2bdb73b9204ec6606dd81 (MD5) Previous issue date: 2012-07-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The nanocomposites of polypropylene (PP) and montmorillonite (MMT) were prepared using a twin screw extruder and reprocessed five times. Whereas the nonpolar nature of the PP was used two different types of coupling agent grafted the polypropylene with maleic anhydride (PP-g-MA) and polypropylene grafted with Acrylic Acid (AA-g-PP) in order to improve the merge process. Samples containing 1,3 and 5% clay obtained at the 3:1 mass ratio of compatibilizer / clay and evaluated the effect of degradation was quantified by X-ray diffraction, infrared spectroscopy,rheological behavior. Formation of color through the system CIE lab and crystallization kinetics. The results of FTIR and Colorimentry followed the same trend with formation of carbonyl number of reworks and rheological analysis show a reduction on molecular weight due to the process of thermo-mechanical degradation of PP and also showed that for the sample containing 5% clay PP-g-MA as a compatibilizer network percolated presented showing that a good dispersion to formulation. Regarding the process of crystallization was observed that the incorporation of MMT promoted a nucleating effect on the PP. The influence of the compatibilizing agent was observed that the PP-g-AA had a nucleating effect additional to the PP / MMT. Regarding the compatibilizer PP-g-MA was observed that the nucleating effect does not occur on the PP Pure occurring including the inhibition of the nucleating effect on the PP/MMT. The influence of the number of extrusions on the crystallisation process, there is generally a strong effect of accelerating the crystallization kinetics due to the increased number of reprocessing. / Os nanocompósitos de polipropileno (PP) e montmorilonita (MMT) foram preparados utilizando extrusora dupla rosca e reprocessados por cinco vezes. Considerando o caráter apolar do PP foi utilizado dois diferentes tipos de agente de acoplamento o polipropileno graftizado com anidrido maleico (PP-g-MA) e o polipropileno graftizado com ácido acrílico (PP-g-AA) a fim de melhorar o processo de intercalação. As amostras contendo 1, 3 e 5% de argila obtiveram na proporção em massa de 3:1 de compatibilizante/argila e foram avaliados o efeito da degradação sendo quantificados por difração de raio X, espectroscopia de infravermelho (FTIR), análises reológicas, formação de cor através do sistema CIE lab e cinética de cristalização. Os resultados de FTIR e colorimentria seguiram a mesma tendência de formação de carbonila com número de reprocessos e as análises reológicas mostram uma diminuição de massa molar devido ao processo de degradação termo-ecânica do PP e mostrou também que para a amostra contendo 5% de argila com PP-g-MA como compatibilizante apresentou uma rede percolada evidenciando uma boa dispersão para essa formulação. Com relação ao processo de cristalização observou-se que a incorporação da MMT promoveu um efeito nucleante sobre o PP. Quanto a influência do agente compatibilizante observou-se que o PP-g-AA apresentou um efeito nucleante adicional em relação ao PP/MMT. Com relação ao compatibilizante PP-g-MA observa-se que não ocorre o efeito nucleante sobre o PP puro ocorrendo inclusive à inibição do efeito nucleante da MMT sobre o PP. Quanto à influência do número de extrusões sobre o processo de cristalização, observou-se em geral um forte efeito de aceleração na cinética de cristalização em função do aumento do número de reprocessos.
113

Reprocessamento de cateteres de angiografia cardiovascular após uso clínico e contaminados artificialmente: avaliação da eficácia da limpeza e da esterilização. / Reprocessing of cardiovascular angiography catheter after clinical use and artificial soil: evaluation of the efficaccy of the cleaning and sterilization.

Silma Maria Cunha Pinheiro Ribeiro 22 May 2006 (has links)
A prática assistencial na área da saúde implica situações de risco, os quais podem ser maximizados, minimizados ou projetados no julgamento à luz da fundamentação científica. O reprocessamento de materiais de uso único é uma prática que, a cada dia, tem exigido esforços dos profissionais de saúde no sentido de buscar e produzir evidências que auxiliem no processo de tomada de decisão em relação à não-realização ou sob que condições podem ser executadas. O objetivo geral deste estudo foi avaliar a aplicação de diferentes processos de limpeza e a esterilização em óxido de etileno a 100% nos cateteres de angiografia cardiovascular com vista à determinação da capacidade de redução da carga microbiana e do resíduo orgânico neles antes e após a utilização pelo paciente, assim como em situações de simulação com testes desafio. Trata-se de pesquisa experimental, aplicada, comparativa e controlada realizado no Research Centre do Saint Boniface General Hospital filiado à University of Manitoba, localizada em Winnipeg no Canadá. Os cateteres foram utilizados uma única vez por pacientes submetidos a angiografia coronariana e à análise de resíduos orgânicos (hemoglobina, carboidrato, proteína e endotoxina) por meio de testes bioquímicos diretos e indiretos utilizando a técnica de espectrofotometria. A carga microbiana foi avaliada por meio da realização de cultura microbiológica por método indireto. Esses experimentos foram realizados em quatro etapas, sendo a primeira imediatamente após o uso dos cateteres para determinação da sujidade basal; a segunda, após o uso pelo paciente e limpeza do cateter por diferentes métodos; a terceira, após o uso pelo paciente, de inoculação de sujidade artificial e limpeza por diferentes métodos e a quarta, após o uso pelo paciente, teste desafio, limpeza e esterilização simulando-se cinco reusos. Foram utilizadas técnicas de estatística descritiva e analítica por meio de testes estatísticos paramétricos (análise de variância) e, quando necessário, testes não paramétricos (Kruskall-Wallis). Em todas as análises estatísticas, foram considerados testes bilaterais com um nível de significância estatística de 5% ou 0,05 e o intervalo de confiança estabelecido foi de 95%. O resultado positivo em qualquer um dos testes de detecção de resíduo orgânico e microbiológico foi indicativo de ineficácia do método de limpeza testado. As unidades amostrais foram submetidas aos seguintes métodos de limpeza: limpeza manual com detergente enzimático com enxágüe em água de torneira ou água tratada com osmose reversa e esterilizada; limpeza manual com detergente contendo peróxido de hidrogênio com enxágüe com água tratada com osmose reversa e esterilizada; limpeza automatizada com detergente enzimático sem enxágüe ou com enxágüe em água tratada com osmose reversa e esterilizada; limpeza sob pressão contínua com detergente contendo peróxido de hidrogênio com enxágüe em água de torneira ou água tratada com osmose reversa e esterilizada. Os resultados obtidos neste estudo apontam para a manutenção da carga microbiana antes e após a limpeza dos cateteres. Antes da execução de qualquer método de limpeza dos cateteres, a freqüência de culturas positivas foi de 8,2%, com uma carga microbiana média de 500UFC/unidade. Após a limpeza dos cateteres a freqüência de culturas positivas foi de 8,3% e a carga microbiana média foi de 250UFC/unidade. Os resíduos orgânicos basais detectados nos cateteres apresentavam-se nas seguintes concentrações: 146,3 µg/unidade de hemoglobina, 628,5 µg/unidade de proteína e 7,0 µg/unidade de carboidrato e 38,0 UE/unidade de endotoxina. Após a realização de cinco simulações, a concentração de hemoglobina indireta foi abaixo do limite de detecção do teste, proteína indireta =107,7 µg/unidade, carboidrato indireto= 340,1µg/unidade e endotoxina=5,4UE/unidade. A análise da concentração dos resíduos orgânicos de acordo com os métodos de limpeza demonstrou diferentes níveis de redução. Os métodos de limpeza que utilizaram o detergente contendo peróxido de hidrogênio apresentaram melhor desempenho em relação aos que utilizaram detergentes enzimáticos, sendo que o do método de limpeza sob pressão contínua foi superior aos demais métodos. Os resultados dos resíduos orgânicos dos cateteres que foram submetidos a cinco simulações de reuso mostraram-se inferiores aos valores médios absolutos de uma única simulação, com exceção da concentração média de carboidrato. / The healthy assistance implies in risk, which can be maximized, minimized or projected based on the scientific data. The reprocessing of single used devices is a practice that each day has demanded efforts of the healthcare professionals in order to search and to produce scientific evidences to help them make decision in relation to not reuse or reuse under safety conditions. The objective of this study was to evaluate different cleaning processes and sterilization in ethylene oxide 100% of the angiographic catheters in order to determine the capacity in reducing of the bioburden and the organic residual before and after patient use, as well as in simulated use with soil test. It is an experimental research, comparative and controlled permed in the Research Centre of the Saint Boniface General Hospital affiliated to the University of Manitoba located in Winnipeg, Canada. The catheters had been used only one time for coronariographic exam and submitted to the analysis of organic residues (hemoglobin, carbohydrate, protein and endotoxin) by in situ and destructive test reading by spectrophotometer. The bioburden was evaluated by microbial culture. These experiments had been performed in four phases, being the first immediately after patient use to determine the basaline soil; the second after patient use and cleaning of the catheter by different methods; the third after patient use, soil test inoculation and cleaning by different methods. The fourth phase was performed after patient use and simulated reuse. Descriptive and analytical statistic analysis by parametric statistical tests (variance analysis) or no parametric tests (Kruskall-Wallis) were performed. Had been considered bilateral tests with a significance level < 0,05 and the confidence interval was 95%. It was considered clening failure of the cleaning process any positive results of the detention of organic and microbiological residue. The catheters were submitted to the following cleaning methods: manual washing with enzymatic detergent with tap water or reverse osmosis sterile rinsing; manual washing with hydrogen peroxide detergent rinsing in reverse osmosis sterile water, automated washing with no rinse or reverse osmose sterile water; hydrogen peroxide detergent pumping with tap water or reverse osmosis sterile rinsing . The results gotten in our study showed the maintenance of the bioburden before and after the cleaning of the catheters. In the baseline phase 8,2% of the cultures were positive cultures and the microbial load was 500CFU/device. After cleaning it was 8,3% and the average microbial load was 250 CFU/device. The baseline organic residues data were hemoglobin 146,3µg/device, protein 628,5 µg/device, carbohydrate 7,0µg/device and endotoxin 38,0EU/device. After five simulated use, the indirect hemoglobin concentration was lower of the test limit of detention, protein = 107,7 µg/device, carbohydrate = 340,1µg/device and endotoxin=5,4EU/device. The organic residual analysis according the cleaning methods found different levels of reduction. The cleaning methods that had used a hydrogen peroxide detergent showed better performance relating the enzymatic detergents methods, as well as hydrogen peroxide detergent pumping with reverse osmosis sterile rinsing was the best method. After simulated use phase the organic residue showed lower concentration, excepted the carbohydrate level.
114

Fysiologiska korrelat av ögonrörelser och emotionell exponering hos friska individer : – en experimentundersökning av mekanismer i Eye Movement Desensitization and Reprocessing (EMDR)

Unger, Max Anders January 2008 (has links)
<p>Eye Movement Desensitization and Reprocessing, EMDR, har i psykoterapiforskning visats vara en effektiv behandlingsmetod av posttraumatiskt stressyndrom, PTSD. Däremot är ögonrörelsestimuleringen, som är ett centralt moment i metoden, kontroversiell och dess funktion inte klarlagd.</p><p>I föreliggande undersökning randomiserades trettiosex friska försökspersoner till en av tre stimuleringsbetingelser: ögonrörelsestimulering, taktil stimulering eller orörligt visuellt stimuli (kontrollgrupp). Stimuleringen kombinerades med imaginär exponering, negativ och positiv. Utfallet av experimentet mättes i olika fysiologiska mätparametrar, samt självskattningar av obehagsnivån (SUD). Resultaten visade signifikant högre hudkonduktansnivå vid ögonrörelsestimulering jämfört med kontrollgruppen, relaterat till aktivering av det sympatiska nervsystemet. Inga signifikanta gruppskillnader fanns i de övriga mätningarna. Mönstret av autonom aktivering kan tyda på att ögonrörelsestimuleringen utlöser eller förstärker en orienteringsrespons, vilket vissa teoretiker föreslagit är den verksamma mekanismen i EMDR. Dock behövs fortsatt forskning för att förstå denna verkan, samt koppling till terapeutisk effekt.</p>
115

Fuel depletion analyses at the Missouri University Research Reactor

Ion, Robert Aurelian, January 2006 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (March 2, 2007) Vita. Includes bibliographical references.
116

Fysiologiska korrelat av ögonrörelser och emotionell exponering hos friska individer : – en experimentundersökning av mekanismer i Eye Movement Desensitization and Reprocessing (EMDR)

Unger, Max Anders January 2008 (has links)
Eye Movement Desensitization and Reprocessing, EMDR, har i psykoterapiforskning visats vara en effektiv behandlingsmetod av posttraumatiskt stressyndrom, PTSD. Däremot är ögonrörelsestimuleringen, som är ett centralt moment i metoden, kontroversiell och dess funktion inte klarlagd. I föreliggande undersökning randomiserades trettiosex friska försökspersoner till en av tre stimuleringsbetingelser: ögonrörelsestimulering, taktil stimulering eller orörligt visuellt stimuli (kontrollgrupp). Stimuleringen kombinerades med imaginär exponering, negativ och positiv. Utfallet av experimentet mättes i olika fysiologiska mätparametrar, samt självskattningar av obehagsnivån (SUD). Resultaten visade signifikant högre hudkonduktansnivå vid ögonrörelsestimulering jämfört med kontrollgruppen, relaterat till aktivering av det sympatiska nervsystemet. Inga signifikanta gruppskillnader fanns i de övriga mätningarna. Mönstret av autonom aktivering kan tyda på att ögonrörelsestimuleringen utlöser eller förstärker en orienteringsrespons, vilket vissa teoretiker föreslagit är den verksamma mekanismen i EMDR. Dock behövs fortsatt forskning för att förstå denna verkan, samt koppling till terapeutisk effekt.
117

Synthesis and testing of a novel soft donor organic extractant molecule for targeted soft metal extraction from aqueous phases

Gullekson, Brian J. 11 January 2013 (has links)
Spent nuclear fuel (SNF) resultant from the generation of nuclear power is a chemically and radiologically diverse system which is advantageous to chemically process prior to geologic disposal. Hydrometallurgy is the primary technology for chemical processing for light water reactor spent fuels, where spent fuel is dissolved in an acid for liquid based separations. The primary means for recovery of desired metals from the SNF solution is liquid-liquid extraction which is based on distribution (partitioning) of the metal ions between two immiscible phases based on thermodynamic favorability. One of the means of increasing this favorability is by designing extractant molecules to be either "harder" or "softer" bases, which will more preferentially extract harder or softer metal ions respectively. This technique is used in designing extractant molecules for targeted extraction as actinides are slightly softer than lanthanides, and precious metals produced in significant quantities from the fission process are especially soft metals. The work performed in this thesis involved the synthesis of a novel soft electron donor organic extractant molecule for testing of targeted soft metal extraction. The molecule synthesized was bis-dibutanethiolthiophosphinato-methane, or S6, a bidentate neutral extractant molecule with significant thiolysis for a softer electron environment. The synthesis technique was refined and the molecule composition and structure was confirmed by ¹H NMR, ³¹P NMR, and elemental analysis. Two metal groups, f-elements (actinides and lanthanides) and soft transition metals were tested for their extractability from nitric acid solutions into an S6 solution in n-dodecane. Aqueous solutions of nitric acid and n-dodecane as an organic diluent are typical liquid-liquid extraction conditions in spent nuclear fuel reprocessing. As extraction experiments were performed with radiotracers, for the soft metal extraction experiment, a mixture of the selected metals was neutron-activated in the OSU TRIGA reactor, as was europium to create a lanthanide radiotracer. Actinides and lanthanides were not seen to effectively extract into the organic or form a precipitate at all, making their partitioning with this extractant seemingly ineffective. Through gamma spectroscopy of an irradiated metal solution post-extraction, it is seen that only silver and palladium preferentially complex in the mixed metal samples into an insoluble organic ligand, dropping out of solution. This effect was more pronounced at higher acid concentrations, but silver was seen to slightly extract to the organic phase at all acid concentrations as well. This testing has shown that the S6 extractant can be used to recover silver and palladium from a mixed metal aqueous solution, such as one resultant from advanced spent nuclear fuel reprocessing operations. This result shows promise for future development of sulfur based organophosphate ligands for targeted extraction of precious metals from solutions. / Graduation date: 2013
118

Development of a Real-Time Detection Strategy for Material Accountancy and Process Monitoring During Nuclear Fuel Reprocessing Using the Urex+3A Method

Goddard, Braden 2009 December 1900 (has links)
Reprocessing nuclear fuel is becoming more viable in the United States due to the anticipated increase in construction of nuclear power plants, the growing stockpile of existing used nuclear fuel, and a public desire to reduce the amount of this fuel. However, a new reprocessing facility in non-weapon states must be safeguarded and new reprocessing facilities in weapon states will likely have safeguards due to political and material accountancy reasons. These facilities will have state of the art controls and monitoring methods to safeguard special nuclear materials, as well as to provide real-time monitoring. The focus of this project is to enable the development of a safeguards strategy that uses well established photon measurement methods to characterize samples from the UREX+3a reprocessing method using a variety of detector types and measurement times. It was determined that the errors from quantitative measurements were too large for traditional safeguards methods; however, a safeguards strategy based on qualitative gamma ray and neutron measurements is proposed. The gamma ray detection equipment used in the safeguard strategy could also be used to improve the real-time process monitoring in a yet-to-be built facility. A facility that had real-time gamma detection equipment could improve product quality control and provide additional benefits, such as waste volume reduction. In addition to the spectral analyses, it was determined by Monte Carlo N Particle (MCNP) simulations that there is no noticeable self shielding for internal pipe diameters less than 2 inches, indicating that no self shielding correction factors are needed. Further, it was determined that HPGe N-type detectors would be suitable for a neutron radiation environment. Finally, the gamma ray spectra for the measured samples were simulated using MCNP and then the model was extended to predict the responses from an actual reprocessing scenario from UREX+3a applied to fuel that had a decay time of three years. The 3-year decayed fuel was more representative of commercially reprocessed fuel than the acquired UREX+3a samples. This research found that the safeguards approach proposed in this paper would be best suited as an addition to existing safeguard strategies. Real-time gamma ray detection for process monitoring would be beneficial to a reprocessing facility and could be done with commercially available detectors.
119

Development of the fundamental attributes and inputs for proliferation resistance assessments of nuclear fuel cycles

Giannangeli, Donald D. J., III 17 September 2007 (has links)
Robust and reliable quantitative proliferation resistance assessment tools are critical to a strengthened nonproliferation regime and to the future deployment of nuclear fuel cycle technologies. Efforts to quantify proliferation resistance have thus far met with limited success due to the inherent subjectivity of the problem and interdependencies between attributes that contribute to proliferation resistance. This work focuses on the diversion of nuclear material by a state and defers other threats such as theft or terrorism to future work. A new approach is presented that assesses the problem through four stages of proliferation: the diversion of nuclear material, the transportation of nuclear material from an internationally safeguarded nuclear facility to an undeclared facility, the transformation of material into a weapons-usable metal, and weapon fabrication. A complete and concise set of intrinsic and extrinsic attributes of the nation, facility and material that could impede proliferation are identified. Quantifiable inputs for each of these attributes are defined. For example, the difficulty of handling the diverted material is captured with inputs like mass and bulk, radiation dose, heating rate and others. Aggregating these measurements into an overall value for proliferation resistance can be done in multiple ways based on well-developed decision theory. A preliminary aggregation scheme is provided along with results obtained from analyzing a small spent fuel reprocessing plant to demonstrate quantification of the attributes and inputs. This quantification effort shows that the majority of the inputs presented are relatively straightforward to work with while a few are not. These few difficult inputs will only be useful in special cases where the analyst has access to privileged, detailed or classified information. The stages, attributes and inputs of proliferation presented in this work provide a foundation for proliferation resistance assessments which may use multiple types of aggregation schemes. The overall results of these assessments are useful in comparing nuclear technologies and aiding decisions about development and deployment of that technology.
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Subcritical transmutation of spent nuclear fuel

Sommer, Christopher Michael 07 July 2011 (has links)
A series of fuel cycle simulations were performed using CEA's reactor physics code ERANOS 2.0 to analyze the transmutation performance of the Subcritical Advanced Burner Reactor (SABR). SABR is a fusion-fission hybrid reactor that combines the leading sodium cooled fast reactor technology with the leading tokamak plasma technology based on ITER physics. Two general fuel cycles were considered for the SABR system. The first fuel cycle is one in which all of the transuranics from light water reactors are burned in SABR. The second fuel cycle is a minor actinide burning fuel cycle in which all of the minor actinides and some of the plutonium produced in light water reactors are burned in SABR, with the excess plutonium being set aside for starting up fast reactors in the future. The minor actinide burning fuel cycle is being considered in European Scenario Studies. The fuel cycles were evaluated on the basis of TRU/MA transmutation rate, power profile, accumulated radiation damage, and decay heat to the repository. Each of the fuel cycles are compared against each other, and the minor actinide burning fuel cycles are compared against the EFIT transmutation system, and a low conversion ratio fast reactor.

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