ALFREDO YUUITIRO ABE
80 resultados
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Artigo IPEN-doc 30639 Nodalization of MISTRA facility for ISP-47 experiment using lumped parameter code COCOSYS2024 - DANTAS, A.C.; GALVAO, H.P.; ABE, A.Y.; GIOVEDI, C.Artigo IPEN-doc 30638 Analysis of the CASP2 experiment in the Battelle Containment model using the code COCOSYS2024 - GALVAO, H.P.; DANTAS, A.C.; ABE, A.Y.; GIOVEDI, C.Artigo IPEN-doc 30604 Improving the technical management of nuclear licensing processes in Brazil2024 - GIOVEDI, C.; FERREIRA, N.; ABE, A.Artigo IPEN-doc 30570 Assessment of burnable poison reactivity in the ATF fuel assembly2024 - ABE, A.; GIOVEDI, C.; CARLUCCIO, T.Artigo IPEN-doc 30532 Nuclear power plants2024 - GIOVEDI, C.; ABE, A.Y.; OLIVEIRA, A.; DE MICHELI, L.Artigo IPEN-doc 29915 Best estimate plus uncertainty analysis of metal-water reaction transient experiment2023 - AVELAR, ALAN M.; DINIZ, CAMILA; CAMARGO, FÁBIO de; GIOVEDI, CLAUDIA; ABE, ALFREDO; CHERUBINI, MARCO; PETRUZZI, ALESSANDRO; MOURÃO, MARCELO B.Uncertainty analysis is applied in the licensing process for nuclear installations to complement best estimate analysis and to verify that the upper bound value is less than the threshold corresponding to the safety parameter of interest. Metal-water reaction is a critical safety phenomenon of water-cooled nuclear reactors at accident conditions, e.g. Loss-Of-Coolant Accidents (LOCA). AISI 348 cladding is able to increase the accident tolerance comparing to Zr-based alloys and differently from other accident tolerant fuel cladding options, there is operational experience of nuclear power plants with stainless steel. In this study, a transient oxidation experiment of AISI 348 by steam was conducted and the major sources of uncertainty were addressed. An evaluation model was developed to calculate the evolution of mass gain during the experiment. Meanwhile, uncertainty propagation of experimental data was performed. The results show that the mass gain predicted by the transient metal-water reaction model lays within the experimental data uncertainty band. Furthermore, the selection of the oxidation kinetics model seems to be important whether the analysis wills to provide conservative results.Artigo IPEN-doc 29914 Assessment of minimum allowable thickness of advanced steel (FeCrAl) cladding for accident tolerant fuel2023 - ABE, ALFREDO; GIOVEDI, CLAUDIA; MELO, CAIO; SILVA, ANTONIO T. eThe ferritic iron-chromium-aluminum (FeCrAl) alloy cladding is considered to be the most promising for near-term application in the ATF framework to replace existing zirconium alloy cladding. Although FeCrAl cladding presents several advantages, it is well known that there are at least two main drawbacks, one is the increased thermal neutron absorption cross-section compared to the current Zr-based cladding resulting in a neutronic penalty and another is tritium higher permeation. In the present study, the minimum allowable thickness of cladding is addressed considering neutronic penalty reduction and the mechanical-structural behavior under the LOCA accident condition. The neutronic penalty assessment was performed using the Monte Carlo code and mechanical-structural performance of the FeCrAl cladding using the TRANSURANUS fuel code, which was modified to consider properly the FeCrAl cladding.Tese IPEN-doc 29731 Análise neutrônica e do comportamento sob irradiação de combustíveis tolerantes à falha2023 - ABE, ALFREDO Y.O presente trabalho apresenta uma avaliação e análise quanto aos aspectos neutrônicos e de desempenho de combustível para os potenciais candidatos a combustíveis tolerantes a falha (ATF). Na fase inicial do trabalho para o levantamento bibliográfico utilizou-se a metodologia baseada na técnica de maturidade tecnológica (TRL) para avaliar as diversas opções e tecnologias desses combustíveis. Esta fase inicial permitiu identificar nos desenvolvimentos dos combustíveis tolerantes a falha as principais lacunas e as atividades necessárias para a obtenção e utilização comercial em reatores de potência. As avaliações e as análises neutrônica e de desempenho do combustível dos principais candidatos à combustíveis tolerantes a falha foram realizadas por meio de simulações computacionais utilizando programas de desempenho do combustível (TRANSURANUS) e neutrônica (SERPENT). As atividades consistiram na avaliação e verificação de um projeto de núcleo de reator constituído de combustíveis tolerantes a falha (combustíveis: UO2, U3Si2, UN, UO2-BeO) e os revestimentos: ZIRLO, SiC, FeCrAl, AISI-348). Para tanto, foram obtidos e avaliados os principais parâmetros associados ao projeto do núcleo do reator. Além disso, o trabalho envolveu a avaliação de desempenho de um dos revestimentos (FeCrAl) do combustível tolerantes a falha mais promissores considerando as condições de operação normal e em cenário de acidente. Como conclusão preliminar das atividades desenvolvidas neste trabalho destaca-se a viabilidade neutrônica dos diferentes combustíveis ATF, no entanto em termos de desempenho do combustível nem todas as opções disponíveis ainda possuem grau de maturidade suficiente para aplicação na indústria nuclear em curto e médio prazo. Destaca-se que este trabalho aborda e busca contribuir com um tema bastante atual e relevante na comunidade nuclear, principalmente os grandes desafios envolvidos no desenvolvimento, fabricação e o licenciamento dos combustíveis tolerantes a falha junto aos órgãos regulatórios.Artigo IPEN-doc 29620 Effectiveness of Ni-based and Fe-based cladding alloys in delaying hydrogen generation for small modular reactors with increased accident tolerance2023 - AVELAR, ALAN M.; CAMARGO, FABIO de; SILVA, VANESSA S.P. da; GIOVEDI, CLAUDIA; ABE, ALFREDO; MOURAO, MARCELO B.This study investigates the high temperature oxidation behaviour of a Ni–20Cr-1.2Si (wt.%) alloy in steam from 1200 °C to 1350 °C by Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD). The results demonstrate that exposed Ni-based alloy developed a thin oxide scale, consisted mainly of Cr2O3. The oxidation kinetics obtained from the experimental results was applied to evaluate the hydrogen generation considering a simplified reactor core model with different cladding alloys following an unmitigated Loss-Of-Coolant Accident (LOCA) scenario in a hypothetical Small Modular Reactor (SMR). Overall, experimental data and simulations results show that both Fe-based and Ni-based alloys may enhance cladding survivability, delaying its melting, as well as reducing hydrogen generation under accident conditions compared to Zr-based alloys. However, a substantial neutron absorption occurs when Ni-based alloys are used as cladding for current uranium-dioxide fuel systems, even when compared to Fe-based alloys.Artigo IPEN-doc 29118 Passive Autocatalytic Recombiner perfomance assessment using COCOSYS2022 - GALVAO, H.P.; SHORTO, J.M.B.; SOBRINHO, G.T.; ABE, A.Y.; GIOVEDI, C.The progression of severe accidents in nuclear reactors is characterized by a diversity of phenomena that are Beyond Design Basis (BDBA), such as Direct Containment Heating (DCH), Molten Corium Concrete Interaction (MCCI), hydrogen detonation, and others. Currently, there are several devices and systems that allow mitigating the progression of these events, avoiding the failure of the physical barriers between the nuclear power plant and the environment. In this context, the present work aims to reproduce the HR-14 experiment carried out at the Thermal-hydraulic, Hydrogen, Aerosols and Iodine (THAI) test facility through the Passive Autocatalytic Recombiners (PAR) performance assessment with the COCOSYS code. The analysis of the convergence of the results was performed using the Fast Fourier Transform Based Method (FFTBM) and showed that the results had sufficient accuracy with the experimental data.