JOSE ANTONIO BATISTA DE SOUZA

JOSE ANTONIO BATISTA DE SOUZA

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Manufacturing high-uranium-loaded dispersion fuel plates in Brazil
2024 - DURAZZO, MICHELANGELO; SOUZA, JOSE A.B.; CARVALHO, ELITA F.U. de; RESTIVO, THOMAZ A.G.; GENEZINI, FREDERICO A.; LEAL NETO, RICARDO M.
The Nuclear and Energy Research Institute (IPEN-CNEN/SP) has developed and made available for routine production the technology for manufacturing dispersion-type fuel elements for research reactors. However, the fuel produced is limited to a uranium loading of 2.3 gU/cm3 (U3O8) or 3.0 gU/cm3 (U3Si2). To reduce Brazil’s dependence on foreign sources of Mo-99, the Brazilian government plans to construct a new research reactor, the 30 MW open pool Brazilian Multipurpose Reactor (RMB), which will mainly produce domestic Mo-99. Low-enriched uranium fuel will be used in the RMB, and increasing uranium loading will be important to increase the reactor core’s reactivity and fuel life. Uranium loadings of 3.2 gU/cm3 for the U3O8-Al and 4.8 gU/cm3 for the U3Si2-Al are considered the technological limit and have been well demonstrated worldwide. This work aimed to study the manufacturing process of these two highly uranium-loaded dispersion fuels and redefine current procedures. Additionally, UMo-Al dispersion fuel has been extensively studied globally and is likely to be the next commercially available technology. This new fuel utilizes a dispersion of UMo alloy with 7–10 wt% Mo, resulting in a uranium loading between 6 and 8 gU/cm3. We also studied this fuel type for potential use in the RMB research reactor. This work outlines the primary procedures for manufacturing these three types of fuels and the necessary adjustments to IPEN-CNEN/SP current technology. The manufacturing process proved to be well adapted to these new fuels, requiring only minor modifications. A comparison was made of the microstructures of fuel plate meat using three types of uranium compounds. The microstructures of U3Si2-Al and U10Mo-Al dispersions were found to be adequate, while that of U3O8-Al meat deviated significantly from the concept of an ideal dispersion.
Nickel electrodeposition in LEU metal foil annular targets to produce Mo-99
2022 - IANELLI, RICARDO F.; SALIBA-SILVA, ADONIS M.; TAKARA, ERIKI M.; GARCIA NETO, JOSE; SOUZA, JOSE A.B.; CARVALHO, ELITA F.U. de; DURAZZO, MICHELANGELO
The most used production route of Mo-99 is through the fission of U-235 in irradiation targets that are irradiated in research reactors. The annular target is a promisor design since it can incorporate high U-235 quantities, thus increasing the production yield of Mo-99. This target type uses a foil of uranium metal enveloped by a thin nickel foil that acts as a diffusion barrier. The process of uranium enveloping with nickel foil is today done manually. This operation risks the nickel foil breaking up during target assembling. In the present work, we studied the nickel electrodeposition over uranium metal foil surfaces to replace nickel foils. A pre-forming procedure of the uranium metal foil by calendering was developed to facilitate the assembling operation. The electrodeposition was done over the uranium foil pre-conformed in a tubular shape. An automated apparatus for electrodeposition of nickel in uranium tubular-shaped foil was developed. The results showed that the high nickel adherence to uranium metal depends on the proper activation of the uranium surface. Among the activation processes studied, the mechanical activation showed good adhesion of the nickel layer, with a loss of only 0.16% of uranium mass. Homogeneous and regular 12 μm thickness electrodeposited layers over the uranium metal were obtained. This work showed that the process could be used in continuous production technology, such as the production of irradiation targets.
Manufacturing LEU-foil annular target in Brazil
2022 - DURAZZO, MICHELANGELO; SOUZA, JOSE A.B.; IANELLI, RICARDO F.; TAKARA, ERIKI M.; GARCIA NETO, JOSE S.; SALIBA-SILVA, ADONIS M.; CARVALHO, ELITA F.U. de
Molybdenum-99 is the most important isotope because its daughter isotope, technetium-99m, has been the most used medical radioisotope. The primary method used to produce Mo-99 derives from the fission of U-235 incorporated in so-called irradiation targets. Two routes are being developed to make Mo-99 by fissioning with low enriched uranium (LEU) fuel. The first adopts UAlx-Al dispersion plate targets. The second uses uranium metal foil annular targets. The significant advantage of uranium foil targets over UAlx-Al dispersion targets is the high density of uranium metal. This work presents the experience obtained in the development of the uranium metal annular target manufacturing steps. An innovative method to improve the procedure for assembling the uranium foil on the tubular target was presented. The experience attained will help the future production of Mo-99 in Brazil through the target irradiation in the Brazilian Multipurpose Reactor (RMB).
Effects of Picture Frame Technique (PFT) on the corrosion behavior of 6061 aluminum alloy
2020 - MILAGRE, MARIANA X.; DONATUS, UYIME; MOGILI, NAGA V.; MACHADO, CARULINE S.C.; ARAUJO, JOAO V.S.; KLUMPP, RAFAEL E.; FERNANDES, STELA M.C.; SOUZA, JOSE A.B. de; COSTA, ISOLDA
The 6061 Al–Mg–Si alloy is used in nuclear fuel plates of nuclear research reactors which are fed with fuel in plate shapes. The production of these plates is based on the picture frame technique (PFT). The picture frame technique (PFT) is a manufacturing process for the fabrication of nuclear fuel plates where the nuclear fuel is encapsulated by Al alloy plates and thermomechanically processed to generate a set with reduced thickness. The effects of PFT on the corrosion resistance of the 6061 aluminum alloy were evaluated in this study by immersion and electrochemical tests in 0.005 mol L−1 NaCl solution. The results showed that the PFT fabrication process increases the corrosion resistance of the 6061 alloy in relation to the conventional 6061-T6, due phase dissolution and lower content of β’’ phase. Also, corrosion propagation gradually changes, with an increasing number of processing steps, from intergranular to intragranular corrosion attack.
Procedures for manufacturing an instrumented nuclear fuel element
2019 - DURAZZO, M.; UMBEHAUN, P.E.; TORRES, W.M.; SOUZA, J.A.B.; SILVA, D.G.; ANDRADE, D.A.
The IEA-R1 is an open pool research reactor that operated for many years at 2 MW. The reactor uses plate type fuel elements which are formed by assembling eighteen parallel fuel plates. During the years of reactor operation at 2 MW, thermohydraulic safety margins with respect to design limits were always very high. However, more intense oxidation on some external fuel plates was observed when the reactor power was increased to 5 MW. At this new power level, the safety margins are significantly reduced due to the increase of the heat flux on the plates. In order to measure, experimentally, the fuel plate temperature under operation, an instrumented fuel element was constructed to obtain temperature experimental data at various positions of one or more fuel plates in the fuel element. The manufacturing method is characterized by keeping the original fuel element design specifications. Type K stainless sheathed thermocouples are mounted into supports pads in unrestricted positions. During the fuel element assembling, the supports pads with the thermocouples are mechanically fixed by interference between two adjacent fuel plates. The thermocouple wires are directed through the space existing at the bottom of the mounting slot where the fuel plate is fixed to the side plates. The number of thermocouples installed is not restricted and depends only on adaptations that can be made on the mounting slots of the standard fuel element side plates. This work describes the manufacturing procedures for assembling such an instrumented fuel element.
Effect of porosity on the manufacturing of U3O8-Al dispersion fuel plates
2017 - DURAZZO, M.; SOUZA, J.A.B.; CARVALHO, E.F.U. de; RIELLA, H.G.
The pore volume present in the starting fuel meat of dispersion fuel plates influences the behavior of its deformation during the fuel plate fabrication by rolling to a great extent. This study was carried out to investigate the influence of pore content in the starting fuel meat on the manufacturing of aluminum-base dispersion fuel plates. Factors that affect the residual porosity present in the meat of the fuel plate were investigated. Results showed that the residual pore volume of aluminum-base dispersion-type U3O8-Al fuel plates depends on the characteristics of the starting fuel meat, which is fabricated by pressing. The residual pore volume depends on the U3O8 concentration. For a particular U3O8 concentration, the rolling process establishes a constant pore volume, which is called equilibrium porosity. The equilibrium porosity is insensitive to the initial pore volume present in the starting fuel meat. The research showed that fuel meat integrity was greatly influenced by the initial porosity of the fuel meat. U3O8-Al dispersion fuel plates were successfully fabricated with uranium loading above 3.0 gU/cm(3). This uranium loading is equivalent to the one used in the U3Si2-Al dispersion fuel, currently operating at the lEA-R1 research reactor of the Nuclear and Energy Research Institute - IPEN/CNEN-SP. The U3O8-Al dispersion fuel can substitute the silicide fuel with advantages such as lower price and simpler manufacturing process.