Yazar "Bastug, Elif Ahsen" seçeneğine göre listele

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    Gamma and Neutron Shielding Performance of ABS Polymer Doped with MoS2 and CaWO4: Experimental and Simulation-Based Study
    (Taylor & Francis Inc, 2025) Bastug, Elif Ahsen; Ogul, Hasan; Bulut, Fatih; Akman, Ferdi
    In this study, acrylonitrile butadiene styrene (ABS) polymer composites reinforced with different weight fractions of MoS2 and CaWO4 were fabricated and investigated for their gamma and neutron shielding capabilities through both experimental and simulation-based approaches. Gamma-ray attenuation measurements were conducted using a NaI(Tl) detector system, while GEANT4 and FLUKA Monte Carlo codes were employed to simulate both gamma and neutron shielding performance. Additionally, theoretical values of mass attenuation coefficients (MACs) were calculated using EpiXS software. Scanning electron microscopy analysis revealed a homogeneous dispersion of CaWO4 and MoS2 particles within the ABS matrix, although some agglomeration was observed at higher loadings. The results demonstrated that MS-3 and CW-3 exhibited superior gamma radiation shielding performance, with a MAC increase of approximately three times compared to ABS-0 at 59.5 keV. Notably, the MS-3 and CW-3 samples exhibited enhanced gamma attenuation, especially in the low-energy range. Simulations also confirmed enhanced neutron shielding efficiency, particularly against thermal neutrons. In addition, the Monte Carlo simulations revealed that CW-3 generated the lowest levels of secondary gamma and neutron radiation, enhancing its overall shielding efficiency. For thermal neutrons, the CW-3 sample transmitted only similar to 8% of neutrons and produced 346 933 secondary photons. These findings highlight the potential of the developed composites as advanced materials for radiation protection in nuclear energy systems, medical facilities, and aerospace engineering.
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    Multi-layered radiation shielding analysis in a Molten Salt Reactor
    (Elsevier Science Sa, 2026) Temel, Ibrahim Halil; Ogul, Hasan; Bastug, Elif Ahsen; Torun, Tunahan Recep; Akman, Ferdi
    Molten Salt Reactors (MSRs) represent an innovative advancement in nuclear energy technology, distinguished by their numerous advantages and potential as a future option for safe and sustainable nuclear energy. In this context, optimizing radiation shielding design in MSRs requires careful consideration of variables such as the reactor's fuel cycle, operating temperature, and neutron spectrum. In terms of neutron spectrum, this study focuses on the analysis of a proposed multi-layered radiation shielding model for a 50 kWth micro-MSR. On this purpose, the reactor was modeled and simulated using SERPENT 1.1.7 Monte Carlo program, enabling the determination of neutrons generated during operation. These neutrons were then utilized as inputs for secondary simulations performed with GEANT4 and FLUKA to evaluate neutron and gamma-ray interactions with the reactor's shielding layers, including secondary radiation effects. The findings of this study provide valuable insights into the design of efficient multi-layered shielding systems, highlighting their effectiveness in radiation shielding and supporting the safe deployment of micro-MSR technology. This work contributes to the growing body of knowledge aimed at advancing MSR development and paves the way for future research into optimizing shielding designs for innovative reactor concepts.
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    Multilayer radiation shielding assessment of the Korean SMART small modular reactor
    (Pergamon-Elsevier Science Ltd, 2026) Ogul, Hasan; Bastug, Elif Ahsen; Torun, Tunahan Recep; Karaagac, Mehmet Onur
    Small Modular Reactors (SMRs) are recognized as a sustainable and versatile nuclear energy solution due to their enhanced safety features, scalability, and adaptability. In this context, this study evaluates the radiation shielding performance and thermodynamic efficiency of the Korean SMART SMR. A multilayer shielding system, comprising SS316L, water, lead, and tungsten, was proposed and assessed using SERPENT, FLUKA, and GEANT4 simulations. Primary neutrons of 6.81 x 1010 (4.5 MeV), 5.90 x 1011 (500 keV), and 2.88 x 1011 (0.025 eV) were effectively attenuated, while secondary gamma-rays and neutrons were reduced to near zero at the outer layers. Energy and exergy efficiencies were 30.41 % and 60 %, respectively, indicating minimal performance compromise due to shielding. These results demonstrate a robust shielding design that ensures safe operation of compact SMRs and supports their deployment in diverse environments, including electricity generation and modular energy systems. The study also highlights the integration of advanced computational tools for comprehensive assessment of SMR performance and radiation safety, providing a foundation for optimizing shielding materials in next-generation nuclear energy applications.