Spelling suggestions: "subject:"neutron flux"" "subject:"neutron lux""
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Determinacao do fluxo integrado de neutrons por meio de medidas da razao isotopica de Cd e GdTOMIYOSHI, IRENE A. 09 October 2014 (has links)
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01382.pdf: 1324582 bytes, checksum: a13259f739e3877599333a2bd263f765 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Utilizacao do metodo nodal absorcao-producao em calculos de distribuicoes de fluxo de neutrons e de potencia em uma dimensao e um grupo de energiaFERREIRA, CARLOS R. 09 October 2014 (has links)
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02573.pdf: 3007952 bytes, checksum: c5ad0aa94fbfe8573f958b6952ebfe9e (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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A Aproximacao FN para a solucao de problemas de transporteFERNANDES, JOSE E. 09 October 2014 (has links)
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01343.pdf: 8187182 bytes, checksum: 1a795b521139f6efcc47c46e35075982 (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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A Distribuicao espacial do fluxo de neutrons no nucleo do reator IEA-R1 ,obtida por meio da ativacao de folhasMESTNIK FILHO, JOSE 09 October 2014 (has links)
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00373.pdf: 1796905 bytes, checksum: 6355b89cc4907b0f691cdfa33e5172a1 (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP
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Medida absoluta do fluxo de neutrons lentos em um feixe colimado .Aplicacao do metodo de ativacao utilizando o ouro e o disprosioLEME, MIRIAM P. de T. 09 October 2014 (has links)
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01130.pdf: 682173 bytes, checksum: 29e0e663ccc9f3c06e833bc806ed4c26 (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP
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Determinação de elementos essenciais e tóxicos em cogumelos comestíveis por análise por ativação com nêutrons / Essential and toxic element determination in edible mushrooms by neutron activation analysisMOURA, PATRICIA L. da C. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:54:44Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:28Z (GMT). No. of bitstreams: 0 / Neste trabalho foram determinados os elementos As, Br, Co, Cr, Cs, Fe, K, Na, Rb, Se e Zn presentes em cogumelos comestíveis adquiridos em grandes centros de compra (supermercados), mercados municipais da cidade de São Paulo e diretamente de produtores da região de Mogi das Cruzes, Suzano, Juquitiba e Mirandópolis. A técnica analítica empregada para a determinação dos elementos nos cogumelos comestíveis foi a Análise por Ativação com Nêutrons Instrumental (INAA). Foram adquiridas espécies dos gêneros Agaricus, Lentinus e Pleurotus no período de novembro de 2006 a março de 2007. Cerca de 150 a 200 mg das amostras de cogumelo liofilizado foram irradiadas em fluxo de nêutrons térmicos de 1012cm-2s-1 por 8 horas no reator nuclear de pesquisa IEA-R1 do IPEN/CNEN/SP. Para a validação da metodologia com relação à exatidão e à precisão foram analisados quatro materiais de referência: INCT-MPH-2 Mixed Polish Herbs e INCT-TL-1 Tea Leaves, NIST SRM 1577b Bovine Liver e Mushroom da IAEA. Foi verificada uma variação nas concentrações dos elementos determinados entre os diferentes gêneros. Em algumas amostras apresentaram o elemento arsênio, em baixas concentrações, possivelmente de uma contaminação no cultivo pelo uso de pesticidas nos substratos de onde os cogumelos retiram seus nutrientes. Os resultados mostram que as amostras das espécies de cogumelos analisadas podem ser consideradas como boa fonte nutricional, principalmente devido aos baixos teores de Na, sendo também uma boa fonte de K, Fe e Zn. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP
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FN method for solving radiation transport problemsMAIORINO, JOSE R. 09 October 2014 (has links)
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01296.pdf: 4114768 bytes, checksum: d4e6cb642ae70a16017316565fe26cab (MD5) / Thesis (Doctor) / IPEN/T / North Caroline State University - NCSU
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Refinement and Validation of Existing Computer Models of the OSU Research Reactor using Activation Analysis and Spectral Unfolding CodesChenkovich, Robert Jeremy 15 April 2008 (has links)
No description available.
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A nonlinear diffusion theory model for xenon-induced flux oscillationsTeachman, John David January 1981 (has links)
A nonlinear model is developed for the xenon induced flux oscillation problem that occurs in nuclear power plants. The model is based on Galerkins' method of weighted residuals applied to multigroup diffusion theory. A similar linear model is developed by the same methods in order to consider the effects of the nonlinearities of the system. The effects of multi- and single-energy group considerations are also examined. Finally, the effects of various number of basis functions used to approximate the flux, iodine, and xenon concentrations is determined.
A partial listing of the computer program XORA, developed from the nonlinear and linear models, is given along with representative input and output from this program. / Ph. D.
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Neutron transport benchmarks for binary stochastic multiplying media : planar geometry, two energy groupsDavis, Ian M. (Ian Mack) 10 March 2005 (has links)
Benchmark calculations are performed for neutron transport in a two material
(binary) stochastic multiplying medium. Spatial, angular, and energy dependence
are included. The problem considered is based on a fuel assembly of a common
pressurized water nuclear reactor. The mean chord length through the assembly is
determined and used as the planar geometry system length. According to assumed
or calculated material distributions, this system length is populated with alternating
fuel and moderator segments of random size. Neutron flux distributions are
numerically computed using a discretized form of the Boltzmann transport equation
employing diffusion synthetic acceleration. Average quantities (group fluxes
and k-eigenvalue) and variances are calculated from an ensemble of realizations
of the mixing statistics. The effects of varying two parameters in the fuel, two
different boundary conditions, and three different sets of mixing statistics are assessed.
A probability distribution function (PDF) of the k-eigenvalue is generated
and compared with previous research. Atomic mix solutions are compared with
these benchmark ensemble average flux and k-eigenvalue solutions.
Mixing statistics with large standard deviations give the most widely varying
ensemble solutions of the flux and k-eigenvalue. The shape of the k-eigenvalue PDF
qualitatively agrees with previous work. Its overall shape is independent of variations
in fuel cross-sections for the problems considered, but its width is impacted
by these variations. Statistical distributions with smaller standard deviations alter
the shape of this PDF toward a normal distribution. The atomic mix approximation
yields large over-predictions of the ensemble average k-eigenvalue and under-predictions
of the flux. Qualitatively correct flux shapes are obtained, however.
These benchmark calculations indicate that a model which includes higher statistical
moments of the mixing statistics is needed for accurate predictions of binary
stochastic media k-eigenvalue problems. This is consistent with previous findings. / Graduation date: 2005
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