AMANDA ABATI AGUIAR
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Artigo IPEN-doc 26357 Analysis of stresses acting on the internal and external surfaces of fuel rod of a pressurized water reactor using computational simulation2019 - LIMA, LEONARDO S.; MELO, CAIO; FARIA, DANILO P.; BERRETA, JOSE; ABATI, AMANDA; GIOVEDI, CLAUDIADuring operation of a Pressurized Water Reactor, the cladding of the fuel rod is subjected to various loads, such as: temperature, internal pressure, and external pressure which generate dimensional and geometric variations in the cladding tube. In the fuel rod, at the operating temperature, the internal pressure comes from the initial pre-pressurizing with Helium gas and the release of fission gases by the UO2 pellets during the irradiation. The external pressure is assumed to be the same as that of the coolant. In this paper, it was proposed the study of a mathematical model for computational simulation using the Finite Element Method to calculate and analyze the mechanical stresses acting on the internal and external surfaces of the fuel rod, adopting the normal operating condition, at 0 W of power. The boundary conditions, such as temperature and pressure profile, come from a modified version of a fuel performance code, considering as cladding material an iron-based alloy (austenitic stainless steel). The fuel rod was modeled and simulated using the Solidworks and ANSYS softwares, respectively. The values of the stresses acting on the cladding tube obtained by simulation were compared to the values obtained by analytical calculation. Then, it was checked the consistency of the adopted mathematical model, in order to ensure the reliability of the computational simulation as a tool to evaluate the stresses acting on the internal and external surfaces of the fuel rod under a PWR environment.Artigo IPEN-doc 26367 PCMI effect study in the fuel rod of a PWR reactor type subjected to power ramps2019 - BERRETTA, JOSE R.; LIMA, LEONARDO S.; REIS, REGIS; AGUIAR, AMANDA A.PWR reactor type, when subjected to the power ramp regime, a mechanical interaction between the cladding and the UO2 pellet (PCMI) may occur in the fuel rod. To investigate this phenomenon were used two softwares, the first was a modified fuel performance code to verify the behavior of fuel rod with steel cladding and another to analyze structural mechanical behavior. The fuel performance code results show that there is no contact between the pellet and the cladding in the fuel rod, considering the estimated burning under normal conditions of reactor operation. Thus, it was adopted the hypothesis of the interaction pellet-cladding occurrence, generated by pellet fragmentation and relocation, and power ramp simulation conditions independent of the ramp time. The simulations results show that the fuel rod maintains its integrity under the conditions of the adopted hypothesis.Artigo IPEN-doc 26355 Sensitivity analysis of fuel rod parameters in steady state condition using TRANSURANUS code2019 - AGUIAR, AMANDA A.; ABE, ALFREDO; GIOVEDI, CLAUDIAIn this paper, a simulation of steady state conditions using TRANSURANUS code applied to Arkansas Nuclear One Unit 2 (PWR) fuel rod is presented. The fuel rod considered in this work was exposed to a peak rod average burnup of 64 GWd/TU, which corresponds to a batch-average exposure of about 53 GWd/TU. TRANSURANUS code offers two different approach for sensitivity analysis: Numerical Noise Analysis and Monte Carlo. In this work, sensitivity analysis using Monte Carlo approach was considered in the range of fuel rod manufacturing parameters, such as internal and external radius of the cladding, external radius of the fuel, and filling gas pressure of the fuel rod, in order to verify some existing correlation with fuel centerline temperature, internal cladding temperature, average tangential stress in the cladding, average permanent tangential strain in the cladding, internal pressure, and fission gas release.Capítulo IPEN-doc 22707 Evaluation of biomimetic coatings on femtosecond laser treated alumina and alumina-zirconia composite surfaces2016 - AGUIAR, A.A.; LIMA, N.B. de; BRAGA, F.J.C.; ROSSI, W.; COUTO, A.A.; BALDAN, R.The effect of texturing Al2O3 and Al2O3/ZrO2 surfaces using fem- 7 tosecond laser has been evaluated in terms of the roughness, wettability and 8 microstructure of the substrate to increase growth efficiency and adhesion of 9 hydroxyapatite. Femtosecond laser treatment of these materials causes phase 10 transformation from alpha-alumina to gamma-alumina. Heat effects during fem- 11 tosecond laser treatment causes the grains to be in the nanometer scale. Without 12 heat effects, the grains are in the micrometer scale. The use of femtosecond laser 13 permits control of the surface roughness of the alumina specimens. The higher the 14 femtosecond laser energy, the higher is the wettability of the specimen and the total 15 surface energy. Specimens with laser textured surfaces upon immersion in 1.5 SBF 16 for 6 and 15 days revealed apatite layers well bonded to the substrate and without 17 detachment. The adhesion of apatite to surfaces of specimens that were not textured 18 with femtosecond laser was inadequateResumo IPEN-doc 22031 Evaluation of biomimetic recovering on the alumina and alumina-zirconia submitted to surface treatment by femtosecond laser2015 - AGUIAR, A.A.; LIMA, N.B. de; ROSSI, W. de; COUTO, A.A.; BALDAN, R.Artigo IPEN-doc 15896 Influencia da pre-deformacao plastica no envelhecimento do aco 180 BH2010 - SOUZA, K.E.R. de; COUTO, A.A.; VATAVUK, J.; OLIVEIRA, B.O.S.R. de; AGUIAR, A.A.Artigo IPEN-doc 15872 Refinamento pelo metodo de Rietveld de uma chapa laminada com orientacao preferencial da liga Al-Mg-Si 60632010 - CARRIO, J.A.G.; LIMA, N.B.; COUTO, A.A.; AGUIAR, A.A.; HATTORI, C.S.; MIRANDA, L.F.; DOMINGUES JUNIOR, N.I.Artigo IPEN-doc 15810 Avaliacao da superficie texturizada em compositos de alumina-zirconia pela utilizacao de laser femtosegundo2010 - AGUIAR, AMANDA A.; ROSSI, WAGNER de; BRAGA, FRANCISCO J.C.; COUTO, ANTONIO A.; LIMA, NELSON B. deArtigo IPEN-doc 17939 Effects of femtosecond laser irradiation on the surfaces of alumina and alumina-zirconia composites2011 - AGUIAR, A.A.; LIMA, N.B.; ROSSI, W. de; SAMAD, R.E.; VIEIRA, N.D.; BRAGA, F.J.C.Tese IPEN-doc 19018 Avaliação do recobrimento biomimético em compósitos de alumina-zircônia texturizadas superficialmente com laser de femtossegundo2013 - AGUIAR, AMANDA A.O principal objetivo deste trabalho foi estudar a influência do tratamento superficial com laser de femtossegundo em amostras de alumina e compósito de alumina-zircônia estabilizada com ítria para depósito e aderência de apatita. Os resultados obtidos mostraram que houve a formação de apatita sobre as superfícies das amostras que foram texturizadas com laser de femtossegundo e em seguida imersa em 1,5 SBF. Este método biomimético pôde, por conseguinte, tornar estas cerâmicas bioativas. Também houve a formação de apatita na superfície das amostras sem o tratamento a laser. Os efeitos da texturização na superfície para as diferentes cerâmicas e a influência do tempo de imersão em 1,5 SBF são discutidos, a fim de determinar a condição ótima para estimular a deposição e a adesão da apatita na superfície dos materiais. Finalmente, os resultados obtidos das diferentes análises são comparados. A adesão da hidroxiapatita é essencial para interação com o substrato e depende das propriedades das superfícies dos materiais. A qualidade desta adesão influenciará sua morfologia e a capacidade futura de osseointegração. As características de superfície dependem da química de superfície, energia de superfície e topografia de superfície. Geralmente, a reatividade de superfície e energia de superfície pode ser influenciada pelas características de molhabilidade, influenciando o desempenho de biomateriais. A adesão e crescimento da apatita depositada também é função da rugosidade superficial. O tratamento superficial com laser de femtossegundo melhora consideravelmente a adesão da apatita obtida pelo recobrimento biomimético nas superfícies dos materiais.