• Title/Summary/Keyword: Shielding Evaluation

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Literature Review on Material Development and Performance Evaluation Method for EMP Shielding Concrete (EMP 차폐 콘크리트 개발 및 성능평가 방법에 관한 문헌 연구)

  • Lee, Woong-Jong;Lee, Hwan;Kim, Young-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.12
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    • pp.67-76
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    • 2020
  • The purpose of this study was to derive the directionality of technology development of high-power electromagnetic pulse (EMP) shielding concrete and standardization of a shielding performance evaluation method. Because the EMP shielding mechanism of concrete has not been identified clearly, and the verification method for EMP shielding performance has not been standardized, it is difficult to compare the research results between researchers. The development direction of EMP shielding concrete was derived from a consideration of the electromagnetic wave loss mechanism of metal. The standardization direction for verifying the EMP shielding performance of concrete was derived from a consideration of the electrical properties of concrete and the shielding performance evaluation methods of previous studies. As a result, the development of electrically conductive concrete is required, and test methods classified by the electromagnetic wave loss mechanism should be applied. For quality verification, the development of EMP shielding concrete will be feasible and its performance can be evaluated if a test method referencing the generalized shielding evaluation method (MIL-STD, etc.) is applied.

An Experimental Study on the Development of EMP Shielding Concrete Using Electric Furnace Oxidized Slag Aggregate (전기로산화슬래그 골재를 사용한 EMP차폐 콘크리트 개발에 관한 실험적 연구)

  • Min, Tae-Beom;Cho, Hyeong-Kyu
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.4
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    • pp.514-520
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    • 2021
  • In this study, EMP shielding performance was evaluated using electric furnace oxidized slag to give EMP shielding performance to concrete among the most used materials in construction sites. As a result of the evaluation, the component of the electric furnace oxidation slag was found to have an Fe2O3 content of 34%, and it was also found to contain an MgO component of about 4.8%. In addition, as a result of conducting an aggregate stability evaluation due to concerns about expansion due to MgO components, it is considered to be suitable for the KS standard. EMP shielding performance evaluation result showed that there was no correlation in EMP shielding performance according to compressive strength, and that general aggregates did not have EMP shielding. However, it was found that the aggregate using the furnace oxidized slag had excellent EMP shielding performance, and the shielding performance improved as the thickness increased. As a result of the durability evaluation, it was found that the EMP shielding concrete has the durability of abortion compared to the general concrete. Through this, it is thought that it will be good to improve the shielding rate if concrete is manufactured using electric furnace oxide slag when constructing EMP shielding structures in the future.

Electric Field Strength and Shielding Effectiveness Comparison According to the Size of Shielding Facility (방호 시설 크기에 따른 전계강도 및 차폐 효과 비교)

  • Kang, Ho-Jae;Huh, Chang-Su;Bang, Jeong-Ju;Choi, Jin-Su;Park, Woo-Chul
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.4
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    • pp.221-225
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    • 2014
  • In modern times, threat of high power electromagnetic wave is increasing. When the electrical grid and communication network are attacked by these high power electromagnetic wave, the whole infrastructure is paralyzed. To protect the infrastructure from these high power electromagnetic wave threat, the shielding facility that can block high power electromagnetic wave is constructed. Also shielding effectiveness evaluation about the constructed facility is important. But, because of space efficiency and saving of construction cost to construct the actual shielding facility, the shielding room wall is generally adjacent to exterior concrete structures. As space between shielding facility wall and concrete structures is very small, arranging the transmitting antenna exterior shielding facility is realistically difficult. Therefore, in this research, The shielding effectiveness measurement plan in the state of exterior narrow space of HEMP shielding facility is presented. And to apply this plan, The influence of shielding effectiveness according to the size of the shielding facility is analyzed.

Evaluation of Electromagnetic Shielding Performance of SiC and Graphite Mixed Mortar (SiC 및 흑연 혼입 모르타르의 전자파 차폐 성능 평가)

  • Park, Oh-Seong;Cho, Hyeong-Kyu
    • Journal of the Korea Institute of Building Construction
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    • v.21 no.5
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    • pp.459-468
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    • 2021
  • Blocking electromagnetic waves on the exterior walls of buildings effectively reduces the intensity of electromagnetic fields in buildings, which leads to attenuation of electromagnetic disturbances, so there is a great interest in developing technologies. In this study, SiC by-products and graphite generated in the semiconductor field were selected and mixed into mortar after pretreatment such as pulverization to evaluate their physical properties and electromagnetic wave shielding performance. Considering the economic efficiency of each shielding material, only 10% volume of the outermost side of the experiment was mixed with each shielding material to evaluate the shielding performance. The shielding performance was predicted when the experiment was manufactured by mixing the shielding material with the entire volume of the experiment using the shielding effect evaluation formula. The results of the experiment showed that the shielding performance was up to 20 dB when SiC grains were mixed with shielding materials, the shielding performance was up to 18 dB when graphite powder was mixed with shielding materials, and the shielding performance was up to 28 dB when SiC powder was mixed with shielding materials, and the shielding performance was close to 30 dB, which is known to have a shielding rate of 99.9%.

Evaluation of 3D Printing Filaments for Radiation Shielding using High Density Polyethylene and Bismuth (고밀도 폴리에틸렌과 비스무트를 이용한 3D 프린팅용 방사선 복합필라멘트 개발 및 차폐능력 평가)

  • Park, Ki-Seok;Kim, Dong-Hyun
    • Journal of the Korean Society of Radiology
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    • v.16 no.3
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    • pp.233-240
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    • 2022
  • Research on the presence or absence of radiation shielding for FDM-type filaments has recently begun to be studied, but filaments with shielding capabilities are not sold in Korea, and not studies yet. Therefore, in this research, we will use HDPE (High Density Polyethylene) as a base material, select bismuth as a reinforcing material to manufacture a composite filament, evaluate the shielding ability, and provide basic data for the development of a radiation shielding composite material using 3D printing.A filament is produced by mixing Bismuth with an effective atomic number 83 with HDPE of PE series and adjusting the content of Bismuth to 20% wt, 30% wt, 40% wt. Compounded filaments were evaluated for their physical properties and shielding capabilities by ASTM evaluation methods. As the bismuth content increases, the density, weight, and tensile strength increase, and the shielding capacity is confirmed to be excellent. As a result of the radiation shielding capacity evaluation, it was confirmed that HDPE (80%) + Bi (20%) showed a shielding rate of 82% at 60 kV and a shielding rate of up to 94% or more at 40% bismuth content. In this study, we confirmed that it was possible to produce a radiation shield that is lighter than the metal particle-containing filaments. Furthermore, that have been shield radiation by using HDPE + Bi filaments, and radiation in the medical and radiation industries. The possibility of using it as a shielding complex was confirmed.

Preliminary study for the development of radiation safety evaluation methodology for industrial kV-rated radiation generator facilities

  • Hye Sung Park ;Na Hye Kwon ;Sang Rok Kim ;Hwidong Yoo;Jin Sung Kim ;Sang Hyoun Choi;Dong Wook Kim
    • Nuclear Engineering and Technology
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    • v.55 no.10
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    • pp.3854-3859
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    • 2023
  • Background: This study aims to develop an evaluator that can quickly and accurately evaluate the shielding of low-energy industrial radiation generators. Methods: We used PyQt to develop a graphical user interface (GUI)-based program and employed the calculation methodology reported in the National Council on Radiation Protection and Measurements (NCRP)-49 for shielding calculations. We gathered the necessary factors for shielding evaluation using two libraries designed for Python, pandas and NumPy, and processed them into a database. We verified the effectiveness of the proposed program by comparing the results with those from safety reports of six domestic facilities. Results: After verifying the effectiveness of the program using the NCRP-49 example, we obtained an average error rate of 1.73%. When comparing the facility safety report and results obtained using the program, we found that the error rate was between 1.09% and 6.51%. However, facilities that did not use a defined shielding methodology were underestimated by 31.82% compared with the program (the final barrier thickness satisfied the shielding standard). Conclusion: The developed program provides a fast and accurate shielding evaluation that can assist personnel that work in radiation generator facilities and government officials in reviewing safety.

The Evaluation of Performance and Usability of Bismuth, Tungsten Based Shields (비스무스, 텅스텐 기반 차폐체의 성능 및 유용성 평가)

  • Park, Hoon-Hee
    • Journal of radiological science and technology
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    • v.41 no.6
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    • pp.611-616
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    • 2018
  • Lead apron is harmful to the human body because it is made at heavy metals, and when worn for long periods of time, it causes pain. Therefore, this paper intended to improve the defects of lead apron by using new material shields. For the comparative evaluation of lead and new material shieldes, the shielding rate and weight were measured and tested based on lead 0.5 mmPb. The rate of shielding was 97% based on lead at 0.5 mm thickness, while The new material shield T3 showed similar shielding rates as lead in 8 layers, and in T2 these values were measured in 11 layers. In addition, similar shielding rate was measured in 12 layers at B2, and 8 layers in BF, and 4 layers in $BF_2$. Comparing the weight of cases when commercialized with apron, T3, T2 and B2 were heavier than lead apron. But BF, $BF_2$ were lighter than the lead apron. Based on the results of the experiment, T3 and T2 can be used as an alternative to lead if human or environmental hazards are considered a priority. However, BF and $BF_2$ should be used if the reduction of external exposure is considered a priority.

Evaluation of Effects of Impurities in Nuclear Fuel and Assembly Hardware on Radiation Source Term and Shielding

  • Taekyung Lee;Dongjin Lee;Kwangsoon Choi;Hyeongjoon Yun
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.21 no.2
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    • pp.193-204
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    • 2023
  • To ensure radiological safety margin in the transport and storage of spent nuclear fuel, it is crucial to perform source term and shielding analyses in advance from the perspective of conservation. When performing source term analysis on UO2 fuel, which is mostly used in commercial nuclear power plants, uranium and oxygen are basically considered to be the initial materials of the new fuel. However, the presence of impurities in the fuel and structural materials of the fuel assembly may influence the source term and shielding analyses. The impurities could be radioactive materials or the stable materials that are activated by irradiation during reactor power operation. As measuring the impurity concentration levels in the fuel and structural materials can be challenging, publicly available information on impurity concentration levels is used as a reference in this evaluation. To assess the effect of impurities, the results of the source term and shielding analyses were compared depending on whether the assumed impurity concentration is considered. For the shielding analysis, generic cask design data developed by KEPCO-E&C was utilized.

Performance Evaluation of Low Frequency Magnetic Field Shielding by Eddy-Current (와전류에 의한 저주파 자기장 차폐 성능 평가)

  • Choi, Hak-Yun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.9
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    • pp.124-128
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    • 2010
  • In this paper, the shielding effectiveness of aluminum shielded room with using eddy-current is calculated and measured after fabricated. The size and thickness of shielded room are decided as $2.4{\times}2.4{\times}2.4[m^3]$ and 12[mm] after AC shielding characteristics by eddy-current of conductive materials is analyzed. To verify the shielding effectiveness, a rectangular helmholtz coil is fabricated to generate magnetic field of 1.37[${\mu}T$] and measured magnetic field inside shielding room for 0.01~10[Hz]. According to calculations and measurements, AC Shielding effectiveness by eddy-current in aluminum is very small for 0.01~2[Hz] and 5 times to 11 times for 5~10[Hz].