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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.
21

Experimentos no reator IPEN/MB-01 com refletores de aço inoxidável, aço carbono e níquel / IPEN/MB-01 reactor experiments with stainless steel, carbon steel, and nickel reflectors

Silva, Graciete Simoes de Andrade e 30 January 2018 (has links)
Os experimentos com refletores nucleares de material pesado foram realizados no reator IPEN/MB-01 utilizando-se chapas de aço inoxidável, de aço carbono ou de níquel, num total de 32 chapas de cada material, inseridas adequadamente na face oeste do núcleo do reator. As chapas têm cerca de 3 mm de espessura. A largura e comprimento axial foram suficientes para cobrir todo o núcleo ativo do reator. Tais experimentos foram realizados com cada tipo de material refletor individualmente. Para cada etapa de colocação de chapas foram efetuadas medidas da reatividade devido à inserção destas no núcleo; bem como da posição crítica das barras de controle com BC1 e BC2 igualmente retiradas. Pôde ser observado que o aumento da absorção de nêutrons e consequente diminuição da moderação de nêutrons dominaram toda a física do problema quando foram inseridas poucas chapas de material refletor (cerca de 5 chapas para o aço inoxidável e aço carbono, e 3 chapas no caso do níquel). Na sequência, a reflexão de nêutrons tornou-se importante superando a absorção neutrônica; a reatividade aumentou até ultrapassar a situação sem chapa (excesso de reatividade zero) obtendo-se um acréscimo (ganho líquido) de reatividade com as 32 chapas inseridas (cerca de 162 pcm no caso do aço inoxidável, 37 pcm para o aço carbono e 295 pcm para o níquel). Portanto, observou-se que o núcleo refletido tornou-se mais reativo do que o núcleo sem material refletor. Resultados experimentais inéditos de medidas de reatividade foram obtidos com refletores de níquel. No que concerne a esse tipo de experimento não existe experimento similar na literatura internacional ao realizado no reator IPEN/MB-01. A análise teórica empregando o MCNP-5 e a biblioteca de dados nucleares ENDF/B-VII.0 evidenciou os aspectos físicos de absorção e reflexão de nêutrons nas chapas de material refletor considerados; entretanto apresentou uma discrepância quando a reflexão de nêutrons rápidos domina o fenômeno físico do transporte de nêutrons. Essas tendências foram encontradas independentemente do tipo de refletor pesado empregado nos experimentos. / Experiments with heavy-material nuclear reflectors were performed in the IPEN / MB-01 reactor using stainless steel, carbon steel or nickel plates, in a total of 32 plates of each material, properly inserted in the western face of the reactor core. The plates are about 3 mm thick. The axial width and length were sufficient to cover the entire active core of the reactor. Such experiments were performed with each type of reflective material individually. For each step of placement of plates were made measures of reactivity due to the insertion of these in the core; as well as the critical position of the BC1 and BC2 control rods also removed. It could be observed that the increase in neutron absorption and consequent decrease in neutron moderation dominated the whole physics of the problem when a few reflective material plates were inserted (about 5 plates for stainless steel and carbon steel and 3 plates for nickel). Subsequently, neutron reflection has become important overcoming neutron absorption; the reactivity increased until it exceeded the situation without plate (excess of zero reactivity) obtaining an increase (net gain) of reactivity with 32 inserts inserted (about 162 pcm in the case of stainless steel, 37 pcm for carbon steel and 295 pcm for nickel). Therefore, it was observed that the reflected core became more reactive than the core without reflective material. Unpublished experimental results of reactivity measurements were obtained with nickel reflectors. As for this type of experiment, there is no similar experiment in the international literature compared to the IPEN/MB-01 reactor. The theoretical analysis using the MCNP-5 together with nuclear data library ENDF/B-VII.0 evidenced the physical aspects of neutron absorption and reflection in the reflective material plates considered; however, it presented a discrepancy when the reflection of fast neutrons dominates the physical phenomenon of the transport of neutrons. These trends were found independently of the type of the heavy reflector employed in the experiments.
22

Obtencao das constantes de decaimento e abundancias relativas de neutrons atrasados atraves da analise de ruido em reatores de potencia zero

DINIZ, RICARDO 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:49:54Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:56Z (GMT). No. of bitstreams: 1 10276.pdf: 7799693 bytes, checksum: 33b179c5ecbae276e3b4235673393d72 (MD5) / Tese (Doutoramento) / IPEN/T / Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP
23

O efeito do refletor sobre o tempo de vida neutrônico no reator IPEN/MB-01 / The reflector effect on the neutron lifeimes in the IPEN/MB-01 reactor

GONNELLI, EDUARDO 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:41:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:23Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
24

Caracterização dos campos neutrônicos obtidos por meio de armadilhas de nêutrons no interior do núcleo do reator nuclear IPEN/MB-01 / Neutronic characterization of the fields obtained by means of neutron traps inside the nuclear reactor core IPEN/MB-01

MURA, LUIZ E.C. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:40Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:05Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
25

Calibração dos canais nucleares do reator IPEN/MB-01, obtida a partir da medida da distribuição espacial do fluxo de nêutrons térmicos no núcleo do reator através da irradiação de folhas de ouro infinitamente diluídas / Calibration of the nuclear power channels of the IPEN/MB-01 reactor obtained from the measurements of the spatial thermal neutron flux distribution in the reactor core through the irradiation of infinitely diluted gold foils

GONCALVES, LUCAS B. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:54:46Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:31Z (GMT). No. of bitstreams: 1 12782.pdf: 5810159 bytes, checksum: 89e60520369008e4796ebb925cf90bdb (MD5) / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP
26

Medida de distribuicao da densidade de potencia relativa do nucleo do reator IPEN/MB-01...vareta combustivel

CARNEIRO, ALVARO L.G. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:42:53Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:38Z (GMT). No. of bitstreams: 1 04993.pdf: 7727472 bytes, checksum: 018707af67fb277f13c457a4276b421e (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
27

Calibração da potência do reator IPEN/MB-01 na configuração cilíndrica de menor excesso de reatividade obtida a partir da medida absoluta do fluxo médio de nêutrons / Power calibration of the IPEN/MB-01 reactor for the cylindrical configuration of minor reactivity excess obtained from the measurements of the absolute average neutron flux

SILVA, ALEXANDRE F.P. da 10 November 2014 (has links)
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2014-11-10T10:53:10Z No. of bitstreams: 0 / Made available in DSpace on 2014-11-10T10:53:10Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
28

Caracterização do núcleo cilíndrico de menor excesso de reatividade do reator IPEN/MB-01, pela medida da distribuição espacial e energética do fluxo de nêutrons / Neutronic characterization of cylindrical core of minor excess reactivity in the nuclear reactor IPEN/MB-01 from the measure of spatial and energetic distribution of neutron flux distribution

AREDES, VITOR O.G. 19 January 2015 (has links)
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-01-19T10:30:20Z No. of bitstreams: 0 / Made available in DSpace on 2015-01-19T10:30:20Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
29

Desenvolvimento do plano preliminar de descomissionamento do reator IPEN/MB-01 / Preliminary decommissioning plan of the reactor IPEN/MB-01

VIVAS, ARY de S. 20 February 2015 (has links)
Submitted by Maria Eneide de Souza Araujo (mearaujo@ipen.br) on 2015-02-20T15:58:48Z No. of bitstreams: 0 / Made available in DSpace on 2015-02-20T15:58:48Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
30

Obtencao das constantes de decaimento e abundancias relativas de neutrons atrasados atraves da analise de ruido em reatores de potencia zero

DINIZ, RICARDO 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:49:54Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:56Z (GMT). No. of bitstreams: 1 10276.pdf: 7799693 bytes, checksum: 33b179c5ecbae276e3b4235673393d72 (MD5) / Tese (Doutoramento) / IPEN/T / Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP

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