• Title/Summary/Keyword: atomic model

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3D-based equivalent model of SMART control rod drive mechanism using dynamic condensation method

  • Ahn, Kwanghyun;Lee, Kang-Heon;Lee, Jae-Seon;Chang, Seongmin
    • Nuclear Engineering and Technology
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    • v.54 no.3
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    • pp.1109-1114
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    • 2022

  • The SMART (System-integrated Modular Advanced ReacTor) is an integral-type small modular reactor developed by KAERI (Korea Atomic Energy Research Institute). This paper discusses the feasibility and applicability of a 3D-based equivalent model using dynamic condensation method for seismic analysis of a SMART control rod drive mechanism. The equivalent model is utilized for complicated seismic analysis during the design of the SMART. While the 1D-based beam-mass equivalent model is widely used in the nuclear industry for its calculation efficiency, the 3D-based equivalent model is suggested for the seismic analysis of SMART to enhance the analysis accuracy of the 1D-based equivalent model while maintaining its analysis efficiency. To verify the suggested model, acceleration response spectra from seismic analysis based on the 3D-based equivalent model are compared to those from the 1D-based beam-mass equivalent model and experiments. The accuracy and efficiency of the dynamic condensation method are investigated by comparison to analysis results based on the conventional modeling methodology used for seismic analysis.

  • https://doi.org/10.1016/j.net.2021.08.037 인용 PDF KSCI

Development of thermal conductivity model with use of a thermal resistance circuit for metallic UO2 microcell nuclear fuel pellets

  • Heung Soo Lee;Dong Seok Kim;Dong-Joo Kim;Jae Ho Yang;Ji-Hae Yoon;Ji Hwan Lee
    • Nuclear Engineering and Technology
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    • v.55 no.10
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    • pp.3860-3865
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    • 2023

  • A metallic microcell UO2 pellet has a microstructure where a metal wall is connected to overcome the low thermal conductivity of the UO2 fuel pellet. It has been verified that metallic microcell fuel pellets provide an impressive reduction of the fuel centerline temperature through a Halden irradiation test. However, it is difficult to predict the effective thermal conductivity of these pellets and researchers have had to rely on measurement and use of the finite element method. In this study, we designed a unit microcell model using a thermal resistance circuit to calculate the effective thermal conductivity on the basis of the microstructure characteristics by using the aspect ratio and compared the results with those of reported metallic UO2 microcell pellets. In particular, using the thermal conductivity calculated by our model, the fuel centerline temperature of Cr microcell pellets on the 5th day of the Halden irradiation test was predicted within 6% error from the measured value.

  • https://doi.org/10.1016/j.net.2023.07.001 인용 PDF