• 제목/요약/키워드: nuclear structure

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진동대 실험을 통한 전단벽 구조물의 층응답 특성 평가 (In-structure Response Evaluation of Shear Wall Structure via Shaking Table Tests)

  • 정재욱;하정곤;함대기;김민규
    • 한국지진공학회논문집
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    • 제25권3호
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    • pp.129-135
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    • 2021
  • After the manual shutdown of the Wolseong nuclear power plant due to an earthquake in Gyeongju in 2016, anxiety about the earthquake safety of nuclear power plants has become a major social issue. The shear wall structure used as a major structural element in nuclear power plants is widely used as a major structural member because of its high resistance to horizontal loads such as earthquakes. However, due to the complexity of the structure, it is challenging to predict the dynamic characteristics of the structure. In this study, a three-story shear wall structure is fabricated, and the in-structure response characteristics of the shear wall structure are evaluated through shaking table tests. The test is performed using the Gyeongju earthquake that occurred in 2016, and the response characteristics due to the domestic earthquake are evaluated.

Issues of New Technological Trends in Nuclear Power Plant (NPPs) for Standardized Breakdown Structure

  • Gebremichael, Dagem D.;Lee, Yunsub;Jung, Youngsoo
    • 국제학술발표논문집
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    • The 8th International Conference on Construction Engineering and Project Management
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    • pp.353-358
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    • 2020
  • Recent efforts to develop a common standard for nuclear power plants (NPPs) with the aim of creating (1) a digital environment for a better understanding of NPPs life-cycle management aspect and (2) engineering data interoperability by using existing standards among different unspecified project participants (e.g., owners/operators, engineers, contractors, equipment suppliers) during plants' life cycle process (EPC, O&M, and decommissioning). In order to meet this goal, there is a need for formulating a standardized high-level physical breakdown structure (PBS) for NPPs project management office (PMO). However, high-level PBS must be comprehensive enough and able to represent the different types of plants and the new trends of technologies in the industry. This has triggered the need for addressing the issues of the recent operational NPPs and future technologies' ramification for evaluating the changes in the NPPs physical components in terms of structure, system, and component (SSC) configuration. In this context, this ongoing study examines the recent conventional NPPs and technological trends in the development of future NPPs facilities. New reactor models regarding the overlap of variant issues of nuclear technology were explored. Finally, issues on PBS for project management are explored by the examination of the configuration of NPPs primary system. The primary systems' configuration of different reactor models is assessed in order to clarify the need for analyzing the new trends in nuclear technology and to formulate a common high-level PBS. Findings and implications are discussed for further studies.

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Stability and nonlinear vibration of a fuel rod in axial flow with geometric nonlinearity and thermal expansion

  • Yu Zhang;Pengzhou Li;Hongwei Qiao
    • Nuclear Engineering and Technology
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    • 제55권11호
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    • pp.4295-4306
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    • 2023
  • The vibration of fuel rods in axial flow is a universally recognized issue within both engineering and academic communities due to its significant importance in ensuring structural safety. This paper aims to thoroughly investigate the stability and nonlinear vibration of a fuel rod subjected to axial flow in a newly designed high temperature gas cooled reactor. Considering the possible presence of thermal expansion and large deformation in practical scenarios, the thermal effect and geometric nonlinearity are modeled using the von Karman equation. By applying Hamilton's principle, we derive the comprehensive governing equation for this fluid-structure interaction system, which incorporates the quadratic nonlinear stiffness. To establish a connection between the fluid and structure aspects, we utilize the Galerkin method to solve the perturbation potential function, while employing mode expansion techniques associated with the structural analysis. Following convergence and validation analyses, we examine the stability of the structure under various conditions in detail, and also investigate the bifurcation behavior concerning the buckling amplitude and flow velocity. The findings from this research enhance the understanding of the underlying physics governing fuel rod behavior in axial flow under severe yet practical conditions, while providing valuable guidance for reactor design.

State-of-the-art progress of gaseous radiochemical method for detecting of ionizing radiation

  • Lebedev, S.G.;Yants, V.E.
    • Nuclear Engineering and Technology
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    • 제53권7호
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    • pp.2075-2083
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    • 2021
  • The article provides a review of the research results obtained during of more than 20 years concerning using the gaseous radiochemical method (GRCM) for detecting of ionizing radiation. This method based on threshold nuclear reactions with production of radioactive noble gas which does not interact with the materials of gaseous tract. The applications of GRCM in the diagnostics of neutrinos, neutrons, charged particles, thermonuclear plasma thermometry, and the study of the structure and dynamics of astrophysical objects, position-sensitive dosimetry of neutron targets with accelerator driving, spatial distribution of the fast neutron flux density in a nuclear reactor allowing the transformation of longitudinal coordinate of neutron flux distribution into a temporal distribution of the radiochemical gas decay counting rate ("barcode" semblance) and measurement of bombarding particles spectra are described. Experimental testing of the described technologies was made on the neutron target driven with the linear proton accelerator of Institute for Nuclear Research of Russian Academy of Sciences (INR RAS).

Wavelet analysis of soil-structure interaction effects on seismic responses of base-isolated nuclear power plants

  • Ali, Shafayat Bin;Kim, Dookie
    • Earthquakes and Structures
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    • 제13권6호
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    • pp.561-572
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    • 2017
  • Seismic base isolation has been accepted as one of the most popular design procedures to protect important structures against earthquakes. However, due to lack of information and experimental data the application of base isolation is quite limited to nuclear power plant (NPP) industry. Moreover, the effects of inelastic behavior of soil beneath base-isolated NPP have raised questions to the effectiveness of isolation device. This study applies the wavelet analysis to investigate the effects of soil-structure interaction (SSI) on the seismic response of a base-isolated NPP structure. To evaluate the SSI effects, the NPP structure is modelled as a lumped mass stick model and combined with a soil model using the concept of cone models. The lead rubber bearing (LRB) base isolator is used to adopt the base isolation system. The shear wave velocity of soil is varied to reflect the real rock site conditions of structure. The comparison between seismic performance of isolated structure and non-isolated structure has drawn. The results show that the wavelet analysis proves to be an efficient tool to evaluate the SSI effects on the seismic response of base-isolated structure and the seismic performance of base-isolated NPP is not sensitive to the effects in this case.

Application of automatic few-group structure optimization based on perturbation theory to VHTR cores

  • Tae Young Han;Hyun Chul Lee
    • Nuclear Engineering and Technology
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    • 제56권10호
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    • pp.4042-4049
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    • 2024
  • A new automatic group structure optimization method based on the perturbation theory was proposed for the few-group structure in two-step nuclear design procedure for VHTR. It applies the sensitivity coefficient of the perturbation theory which includes not only the effect of the cross section on the multiplication factor but also the adjoint weighted reaction rate. The sensitivity coefficient of the fine group for the multiplication factor was calculated and the group boundary for a few-group can be determined so that the summation of the fine group sensitivity for a few-group should be evenly distributed over every few-group. This method was successfully implemented in the ABGO code. VHTR-350 and MiHTR 2D core were used to investigate the performance and applicability of the proposed method. The code generated the new group structures for two cores and the error of the multiplication and reaction rate by the new group structure was compared with the result by the fine group structure. The comparisons indicate that the new group structure by the proposed method can provide the multiplication factor and reaction rates comparable to the existing group structure and more accurate results than the group structure obtained using the Contributon theory.

원자력발전소 파워블럭에 대한 구조물-지반-구조물 상호 작용과 다양한 매개변수를 고려한 지진응답해석 (Seismic Response Analyses for Whole Power Block of Nuclear Facilities Considering Structure-Soil-Structure Interaction and Various Parameters)

  • 서춘교;장동휘;정두리;장수혁;문일환
    • 한국지진공학회논문집
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    • 제22권6호
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    • pp.333-343
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    • 2018
  • In this paper, we study the existing results of the structure-soil-structure interaction (SSSI) effect on seismic responses of structures and summarize important parameters. The parameters considered in this study are a combination of buildings in the power block of a nuclear power plant, the characteristics of earthquake ground motions and its direction, and the characteristics embedded under the ground. Based on these parameters, the seismic analysis model of the structures in the power block of the nuclear power plant is developed and the structure-soil-structure interaction analyses are performed to analyze the influence of the parameters on the seismic response. For all analyses, the soil-structure interaction (SSI) analysis program CNU-KIESSI, which was developed to enable large-sized seismic analysis, is used. In addition, the SSI analyses is performed on individual structures and the results are compared with the SSSI analysis results. Finally, the influence of the parameters on the seismic response of the structure due to the SSSI effect is reviewed through comparison of the analysis results.