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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.
241

The Price of Uranium : an Econometric Analysis and Scenario Simulations

Kroén, Johannes January 2019 (has links)
The purpose of this thesis is to analyze: (a) the determinants of the global price of uranium; and (b) how this price could be affected by different nuclear power generation scenarios for 2030. To do this a multivariable regression analysis will be used. Within the model, the price of uranium is the dependent variable and the independent variables are generated nuclear power electricity representing demand (GWh), price of coal as a substitute to generated nuclear power electricity, and the price of oil representing uranium production costs. The empirical results show that generated nuclear electricity and the oil price, to be statistically significant at the 5 percent level. The coal price was not however a statistically significant. The scenarios for 2030 are three possible nuclear power generation demand cases; high, medium and low demand. The results for the high demand generated a price of 255 US$/kg and the medium demand 72US$/kg.
242

Best practice in transporting uranium oxide from a Namibian perspective in response to an increased demand for clean energy in the global arena

Coetzee, Philip Barry 03 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2006. / ENGLISH ABSTRACT: The International Energy Agency will for the first time in its 32 years history urge governments to speed up the construction of nuclear power plants. According to Fatih Birol, lEA chief economist, "the decision almost needs to be made tomorrow if we are going to act before we reach a point of no return in climate and security of supply." Nuclear energy, through the conversion and enrichment of uranium oxide, is one of the energy sources with the potential to make an immediate and substantial difference in the emission of greenhouse gasses. Uranium Oxide currently provides a cost effective and sustainable source of clean energy through nuclear power generation, directly comparable in price to gas and coal. With the growth of the world economy, comes a requirement for more energy. This can only be sustained through a number of sources, of which uranium and renewable sources of energy i.e. wind power generation, is part of. The supply of uranium oxide from production to conversion is key to the success of the uranium industry. The high energy potential of relative small quantities of uranium makes rt ideal to transport as the cost and handling is reduced. The transportation of uranium oxide is continuously increasing in complexity. This combined with a high price scenario, increased demand and supply shortages increases the risk associated with denial and delays of shipments. / AFRIKAANSE OPSOMMING: Die Internasionale Energie Agentskap gaan vir die eerste keer in die organisasie se 32-jaar geskiedenis' regerings aanspoor om die konstruksie van kemkragsentrales te bespoedig. Volgens Fatih Birol, IEA se hoof-ekonoom, "moet die besluit amper more geneem word as ons gaan reageer voor ons 'n punt van geen omdraai bereik het ten opsigte van die klimaat en sekuriteit van aanbod." Kernkrag, deur die omskakeling en verryking van uraanoksied, is een van die energie bronne met die potensiaal om 'n onmiddelike en substansiele verskil in die vrylating van groenhuis-gasse te maak. Uraanoksied verskaf huidiglik 'n koste effektiewe en volhoudbare bron van skoon energie deur kernkrag opwekking, direk vergelykbaar met steenkool en gas. Met die groei in die wereld ekonomie, kom die vraag na meer energie. Dit kan slegs volhoudbaar wees uit 'n aantal bronne waarvan uraan en hernubare bronne soos windkrag-opwekking, deel is. Die verskaffing van uraanoksied van produksie tot verryking is die sleutel tot die sukses van die uraan industrie. Die hoe energie potensiaal van relatiewe klein hoeveelhede uraan, maak dit geskik vir vervoer omdat die koste van vervoer en hantering verminder word. Die transportering van uraan oksied is voortdurend besig om in kompleksiteit toe te neem. Gekombineerd met 'n hoe prys senario, verhoogde vraag na en aanbodtekorte, verhoog die risiko verbind met wyering en vertragings in verskeping.
243

Design and development of an automated uranium pellet stacking system

Riess, Brian Scott 01 June 2009 (has links)
A novel design for an automated uranium pellet stacking system is presented. This system is designed to replace the manual method for stacking uranium pellets for CANDU fuel bundles that is currently used at Cameco Fuel Manufacturing in Port Hope, ON. The system presented is designed as a drop-in solution to the current production line at Cameco. As a result, there are constraints that prevent certain parameters from modification. The three main goals of this system are to reduce worker exposure to radiation to as low as reasonably achievable, improve product quality, and increase the productivity of the production line. The proposed system will remove the workers from a position of having to handle the uranium pellets and physically place them on the stacks. While the natural uranium currently in production is not a major health risk for short-term exposure, the possibility of production of slightly enriched uranium bundles makes this system a real need. This system also removes the random pellet placement that the manual system uses by taking precise measurements using laser triangulation sensors. These measurements are used to determine which sizes of end pellets are required to complete the stack to within the specified tolerances. A final measurement is done to ensure the stack is within tolerance. All of this information is recorded and can be traced back to the stacks during quality inspection, which is a major improvement over the existing system. This single automated system will replace two manual stations, while increasing the total output production, thus eliminating pellet stacking as a bottleneck in the fuel bundle assembly process. Current production rates can be met by this single, automated station in two shifts per day, while the current manual process requires three shifts using two stations. Test results of a proof-of-concept prototype indicate that the proposed design meets or exceeds all of the design requirements.
244

Safeguards assessment of gamma-ray detection for process monitoring at natural uranium conversion facilities

Dewji, Shaheen Azim 22 May 2014 (has links)
Conversion, the process by which natural uranium ore (yellowcake) is purified and converted through a series of chemical processes into uranium hexafluoride gas (UF6), has historically been excluded from the nuclear safeguards requirements of the 235U-based nuclear fuel cycle. With each step in the conversion process from yellowcake to feedstock for UF6, intermediary uranium oxide and uranium fluoride compounds become progressively attractive products for diversion toward activities noncompliant with international treaties. The diversion of this product material could potentially provide feedstock for a clandestine or undeclared enrichment for weapons development for state or non-state entities. With the realization of this potential, the International Atomic Energy Agency (IAEA) has only recently reinterpreted its policies to emphasize safeguarding this feedstock in response to such diversion pathways. This project employs a combination of simulation models and experimental measurements to develop and validate concepts of nondestructive assay monitoring systems in a natural uranium conversion plant (NUCP). In particular, uranyl nitrate (UN) solution exiting solvent extraction was identified as a key measurement point (KMP), where gamma-ray spectroscopy was selected as the process-monitoring tool. The Uranyl Nitrate Calibration Loop Equipment (UNCLE) facility at Oak Ridge National Laboratory was employed to simulate the full-scale operating conditions of a purified uranium-bearing aqueous stream exiting the solvent extraction process in an NUCP. This work investigates gamma-ray signatures UN circulating in the UNCLE facility and evaluates various gamma-ray detector (HPGe, LaBr3 and NaI) sensitivities to UN.
245

Determinacao de impurezas em compostos de uranio por meio da tecnica de espectrometria de massas de alta resolucao com fonte de plasma indutivo (HR-ICPMS)

ULRICH, JOAO C. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:46:10Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:57Z (GMT). No. of bitstreams: 1 07537.pdf: 6037545 bytes, checksum: e5c0c7ed539b9c85328768099422ceff (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
246

Aplicação da quimiometria para caracterização química de combustíveis tipo MTR por fluorescência de raios X / Chemometrics application in fuel's MTR type chemical characterization by x-ray fluorescence

SILVA, CLAYTON P. da 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:35:27Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:40Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
247

Raman spectroscopy for the characterization of defective spent nuclear fuels during interim storage in pools / Apport de la spectroscopie Raman pour la caractérisation des combustibles nucléaires défectueux en condition d'entreposage sous eau

Mohun, Ritesh 07 November 2017 (has links)
Une signature spécifique des dommages d’irradiation dans le dioxyde d’uranium, le combustible nucléaire le plus utilisé, dénommé « triplet de défauts » a été récemment mis en évidence par spectroscopie Raman. Ce travail vise à savoir comment cette signature peut être utilisée afin de caractériser les combustibles nucléaires irradiés qui sont entreposés sous eau. Pour cela, trois études à effets séparés sont menées. Tout d’abord, une expérience d’irradiation aux électrons montre que le triplet de défauts est dû à des interactions balistiques et est associé aux déplacements dans le sous-réseau d’uranium. Après l’irradiation aux électrons, l’échantillon d’UO2 s’oxyde de manière accélérée, ce qui a été attribué à la migration des lacunes d’oxygène créées par l’irradiation vers la surface. Ensuite, la cinétique de formation du triplet de défauts dans de l’UO2 exposé à des environnements inerte (Ar) et réactif (eau aérée) a été mesurée grâce à un dispositif Raman in-situ. Dans tous les cas, la cinétique peut être décrite par un modèle d’impact direct, mais avec des coefficients numériques différents. Enfin, de manière à simuler le combustible irradié industriel en laboratoire, l’étude de différents composés d’oxydes mixtes a montré le rôle du dopage chimique sur la formation du triplet de défauts. Ces informations seront mises à profit dans les études futures de combustibles défectueux entreposés sous eau. / A specific signature characteristic of irradiation damages in uranium dioxide, the most used nuclear fuel, referred as « triplet defect bands» has recently been evidenced by Raman Spectroscopy. The objective of this study is to determine how this signature can be used to characterize actual spent nuclear fuel stored in pools. For that purpose, three separate effect studies were carried out. Firstly, an electron irradiation experiment shows that the triplet defect bands are due to ballistic interactions and result from the formation displacements in the uranium sub-lattice. Post electron irradiation, the enhanced oxidation of UO2 samples is observed and attributed to the migration of irradiation induced oxygen vacancies towards the surface. The formation kinetics of the triplet defect bands in UO2 when exposed to an inert (Ar) and a reactive (aerated water) contact medium is then investigated through the use of an in-situ Raman installation. Both kinetics can be fitted using a direct impact model, but with different numerical values. Finally, to simulate actual spent nuclear fuels in laboratory conditions, the study of different mixed oxide compounds shows that chemical doping impacts the apparition of the Raman triplet defect bands. The experimental results obtained in this work will be used as complementary data for the interpretation of Raman results of actual defective spent nuclear fuels stored in pool conditions.
248

Determinacao de impurezas em compostos de uranio por meio da tecnica de espectrometria de massas de alta resolucao com fonte de plasma indutivo (HR-ICPMS)

ULRICH, JOAO C. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:46:10Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:57Z (GMT). No. of bitstreams: 1 07537.pdf: 6037545 bytes, checksum: e5c0c7ed539b9c85328768099422ceff (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
249

Aplicação da quimiometria para caracterização química de combustíveis tipo MTR por fluorescência de raios X / Chemometrics application in fuel's MTR type chemical characterization by x-ray fluorescence

SILVA, CLAYTON P. da 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:35:27Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:40Z (GMT). No. of bitstreams: 0 / No Brasil e no mundo a tecnologia nuclear vem ocupando posição de destaque com diversas aplicações na indústria, geração de energia, meio ambiente e na medicina, melhorando a qualidade de exames e tratamentos, consequentemente, a vida das pessoas. O urânio é o principal elemento utilizado em instalações nucleares, servindo como material base desde a geração de eletricidade à fabricação de radiofármacos. Nos anos 50, em meio à guerra fria, a então recém-criada Agência Internacional de Energia Atômica se propôs a supervisionar instalações nucleares e incentivar a fabricação de combustíveis nucleares com baixo teor de urânio, conhecidos como combustíveis do tipo Material Test Reactor (MTR), fabricados inicialmente na forma de U3O8 e mais tarde o U3Si2, ambos dispersos em alumínio. A utilização desta tecnologia requer uma constante melhoria de todos os processos que envolvem a fabricação do MTR sujeita a diversos protocolos internacionais, os quais procuram garantir a confiabilidade desse combustível do ponto de vista prático e ambiental. Dentro desse contexto, o controle de impurezas, do ponto de vista da economia de nêutrons, afeta diretamente a qualidade de qualquer combustível nuclear, fazendo-se necessário um controle rigoroso. A literatura reporta procedimentos que, além de gerar resíduos, são demorados e dispendiosos, pois necessitam de curva de calibração univariada e materiais de referência. Assim, o objetivo deste trabalho é estabelecer e validar uma metodologia de análise química quantitativa não destrutiva, de baixo custo e tempo de análise, tal como, minimizar a geração de resíduo para a determinação multielementar dos maiores constituintes (Utotal e Si) e as impurezas (B, Mg, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd e outros) presentes em U3O8 e U3Si2, atendendo as necessidades de reatores nucleares na qualificação de combustíveis nucleares do tipo MTR. Para tanto, foi aplicada a técnica de fluorescência de raios X que permite análises químicas rápidas e não destrutivas, além de não necessitar de tratamentos químicos prévios (dissolução, digestão e outros) na fase de preparação de amostras. Para as correções de efeitos espectrais e de matriz foram aplicados e avaliados os métodos de parâmetros fundamentais, de curva de calibração univariada e de calibração multivariada. Os resultados foram comparados por meios de testes estatísticos em conformidade com a norma ISO 17025 com os MRCs (123(1-7) e 124(1-7)) de U3O8 da New Brunswick Laboratory (NBL) e 16 amostras de U3Si2 cedidas pelo CCN do IPEN-CNEN-SP. A quimiometria demonstrou-se um método promissor para a determinação de maiores e menores constituintes em combustíveis nuclear a base de U3O8 e U3Si2, uma vez que a precisão e exatidão são estatisticamente iguais aos métodos de análises volumétrica, gravimétrica e ICP-OES. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
250

A cost estimate for uranium recovery from seawater using a chitin nanomat adsorbent

Lindner, Harry Dreyfus 07 October 2014 (has links)
Even at 3.3 ppb, seawater contains a uranium supply large enough to power the world’s nuclear fleet for 13,000 years. This large supply has prompted interest in technologies for recovering uranium from seawater. Since the 1960’s, economic models of such technologies have failed to produce an economically competitive strategy when compared to conventional uranium recovery from terrestrial mining. Thus, uranium from seawater is researched as a potential price ceiling because of the large supply but high recovery cost. Such an upper bound is still valuable research because it allows for more certainty in uranium prices for planning, research, development and deployment of nuclear power systems. This thesis explores past cost estimates for uranium recovery from seawater and adds a new cost estimate to the pool of literature. The past estimates showed a development from systems that actively moved seawater to systems that allowed adsorbent to sit passively in seawater. The adsorbent material changed from hydrous titanium oxide to the higher-capacity amidoxime ligand. Capacity was the strongest driver of cost. Early models with the amidoxime ligand used an acrylic substrate or backbone. This substrate was later replaced by polyethylene because of its increased durability and lower cost. However, each of those materials could contribute to the problem of plastics in the ocean. The new technology assessed for cost in this paper attempts to address the plastics concern by replacing the plastic with a high molecular weight chitin nanomat as the substrate for the amidoxime ligand. The cost assessment showed the technology is presently cost prohibitive largely due to the adsorption capacity and chitin nanomat production costs. To increase capacity, the grafting efficiency onto the chitin substrate must be improved in order to achieve capacities comparable to those observed for the amidoxime-polyethylene adsorbent. To reduce chitin nanomat production costs, the ionic liquid (IL) consumption must be reduced and the recyclability of IL must be achieved. / text

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