Yazar "Aygun, Bunyamin" seçeneğine göre listele

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    Determination and Fabrication of New Shield Super Alloys Materials for Nuclear Reactor Safety by Experiments and Cern-Fluka Monte Carlo Simulation Code, Geant4 and WinXCom
    (Iop Publishing Ltd, 2016) Aygun, Bunyamin; Korkut, Turgay; Karabulut, Abdulhalik
    Despite the possibility of depletion of fossil fuels increasing energy needs the use of radiation tends to increase. Recently the security-focused debate about planned nuclear power plants still continues. The objective of this thesis is to prevent the radiation spread from nuclear reactors into the environment. In order to do this, we produced higher performanced of new shielding materials which are high radiation holders in reactors operation. Some additives used in new shielding materials; some of iron (Fe), rhenium (Re), nickel (Ni), chromium (Cr), boron (B), copper (Cu), tungsten (W), tantalum (Ta), boron carbide (B4C). The results of this experiments indicated that these materials are good shields against gamma and neutrons. The powder metallurgy technique was used to produce new shielding materials. CERN - FLUKA Geant4 Monte Carlo simulation code and WinXCom were used for determination of the percentages of high temperature resistant and high-level fast neutron and gamma shielding materials participated components. Super alloys was produced and then the experimental fast neutron dose equivalent measurements and gamma radiation absorpsion of the new shielding materials were carried out. The produced products to be used safely reactors not only in nuclear medicine, in the treatment room, for the storage of nuclear waste, nuclear research laboratories, against cosmic radiation in space vehicles and has the qualities.
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    Experimental and Monte Carlo simulation study on potential new composite materials to moderate neutron-gamma radiation
    (Pergamon-Elsevier Science Ltd, 2020) Aygun, Bunyamin; Sakar, Erdem; Singh, V. P.; Sayyed, M. I.; Korkut, Turgay; Karabulut, Abdulhalik
    In this study, 12 different concentrations of shielding materials were developed and produced. They were covered with high temperature resistant (1500 degrees C) sodium silicate sealing paste. Epoxy resin was produced by adding different percentages of additive materials such as chromium oxide (Cr2O3), lithium (LiF), and nickel oxide (NiO). The GEANT4 and FLUKA codes of the Monte Carlo simulation toolkit were used to determine the mixing ratios. The total macroscopic cross-sections, effective removal cross-sections, mean free path, half value layer, and transmission neutron number were determined for fast neutron radiation using GEANT4 and FLUKA simulation codes. The mass attenuation coefficient, the effective atomic number and half-value layer (HVL) of the samples were calculated using Phy-X/PSD software. The absorbed dose was measured. In this study, an Am-241-Be neutron source with 74 GBq activity and average neutron energy of approximately 4.5 MeV and a BF3 gas detector were used. Both simulation and experimental measurements were compared with paraffin and conventional concrete. The new composite shielding material absorbed radiation much better than the reference materials. This new radiation shielding composite material can be used in nuclear medicine, transport and storage of radioactive waste, nuclear power plants, and as a shielding material for neutron and gamma radiation.
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    Investigation of high-temperature-resistant rhenium-boron neutron shields by experimental studies and Monte Carlo simulations
    (Springer Singapore Pte Ltd, 2018) Korkut, Turgay; Korkut, Hatun; Aygun, Bunyamin; Bayram, Ozkan; Karabulut, Abdulhalik
    In this study, novel rhenium-boron neutron-shielding high-temperature-resistant materials were designed. The considered samples, Re60-B40, Re58-B42, Re50-B50, and Re40-B60, with different concentrations of rhenium and boron were investigated to elucidate their neutron-shielding performances, and compare them with well-known neutron-shielding materials such as the 316LN quality nuclear steel. In addition to the experimental studies, Monte Carlo simulations were performed using the FLUKA and GEANT4 codes, where 4.5-MeV neutrons emitted by a Am-241-Be source were employed. Experimental equivalent dose rates, simulated track lengths, energy balances, and neutron mass absorption cross sections were discussed in detail.
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    New high temperature resistant heavy concretes for fast neutron and gamma radiation shielding
    (Walter De Gruyter Gmbh, 2019) Aygun, Bunyamin; Sakar, Erdem; Korkut, Turgay; Sayyed, Mohammed Ibrahim; Karabulut, Abdillhalik
    In the present work, we developed three new high temperature resistant heavy concretes as novel radiation shielding materials. For this purpose, chrome ore (FeCr2O4), hematite (Fe2O3), titanium oxide (TiO2), aluminum oxide (Al2O3), hematite [FeO(OH) nH(2)O], siderite (FeCO3), barite (BaSO4), nickel oxide (NiO) materials and alumina cement were used. Mass combination ratios of components and total macroscopic cross sections (scattering, absorption, capture, fission) of the samples were calculated by using GEANT4 code. The resistances of the prepared samples were evaluated in terms of compression strength after exposure at the 1000 degrees C temperature. Neutron equivalent dose rate measurements were carried out by using 4.5 MeV Am-241-Be neutron source and BF3 detector. All results were compared with normal weight concrete and paraffin. The results of neutron dose indicate that neutron absorption ability of the new heavy concretes is higher than normal weight concrete and paraffin. In addition to neutron measurements, different gamma-ray shielding parameters such as mass attenuation coefficient (MAC), effective atom numbers (Z(eff)), half value layer (HVL) and mean free path (MFP) have been calculated using WinXCOM software in order to investigate the effectiveness of using the prepared concretes as a radiation shielding materials. Gamma-ray results were compared with concretes and Pb-based glass.
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    Study of neutron attenuation properties of super alloys with added rhenium
    (Springer, 2015) Korkut, Turgay; Aygun, Bunyamin; Bayram, Ozkan; Karabulut, Abdulhalik
    In this paper, the new generation of rhenium enriched super alloys with enhanced neutron attenuation properties was investigated. These materials provided improved neutron shielding capabilities compared to other shielding materials such as water, concrete, etc. The GEANT4 code was used to simulate transport of Am-Be source neutrons in new shielding materials. Neutron equivalent dose rate measurements were carried out to obtain the dose rate reduction. It was demonstrated that new rhenium enriched alloys are feasible for neutron shielding applications.