• 전기의세계
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• v.29 no.1
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• pp.65-72
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• 1980

Arstrong-Whitehead theory on effective shielding and shielding failure is extended so that it is applicable to vertical line configuration the existing approaches on back-flash rate calculation are summerized and compared in particular on Model Line, and the usefulness of the whitehead approach is suggested.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.48-54
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• 2023

In this research, The basic physical properties and EMP shielding performance by thickness were evaluated for optimum composition of EMP shield concrete that can be applied on-site by mixing carbon-based materials with high conductivity into concrete that uses electric furnace oxidized slag (EOS). As a result of the evaluation, it was confirmed that the slump decreased as the amount of mixed carbon fib er (CF) increased, and increased when milled carb on (MCF) was mixed. As for the compressive strength, it was confirmed that EOS enhanced the strength compared to NA, and it was confirmed that the strength decreased when CF and MCF were mixed. As the thickness of the EMP shielding measurement increases, the shielding rate increases, and it was confirmed that the type of conductive material and the thickness of the test specimen have a greater influence on the shielding rate than the Amount of conductive material added. As a result of a comparative evaluation, EOS CF 0.2 is considered suitable for EMP shield concrete formulation.

• Progress in Medical Physics
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• v.33 no.4
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• pp.164-171
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• 2022

The number of facilities using radiation generators increases and related regulations are strengthened, the establishment of a shielding management and evaluation technology has become important. The characteristics of the radiation generator used in previous report differ from those of currently available high-frequency radiation generators. This study aimed to manufacture lead, iron, and concrete shielding materials for the re-verification of half-value layers, tenth-value layers, and attenuation curve. For a comparison of attenuation ratio, iron, lead, and concrete shields were manufactured in this study. The initial dose was measured without shielding materials, and doses measured under different types and thicknesses of shielding material were compared with the initial dose to calculate the transmission rate on 50-300 kVp X-ray. All the three shielding materials showed a tendency to require greater shielding thickness for higher energy. The attenuation graph showed an exponential shape as the thickness decreased and a straight line as the thickness increased. The difference between the measurement results and the previous study, except in extrapolated parts, may be due to the differences in the radiation generation characteristics between the generators used in the two studies. The attenuated graph measured in this study better reflects the characteristics of current radiation generators, which would be more effective for shield designing.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.4
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• pp.469-484
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• 2020

This study focused on shielding through inflatable structure in the event of sudden water inflow into the submerged floating tunnels. Currently, there is a lack of measures to deal with unexpected water in tunnels in Korea. Although water treatment facilities such as waterproofing and floodgates in tunnels are installed, there are limitations to the sudden inflow of large amounts of seawater or underground water. Also, floodgates cannot respond quickly to sudden damage due to slow blocking time. Accordingly, a study was conducted on the shielding rate and axial movement distance for inflatable structure. The results of the reduced model experiment confirmed that the number of inflatable structure and internal pneumatic pressure influence on the shielding rate. As the number of inflatable structure increased from one to two, the shielding rate increased by about 35 up to 40 percent. It was also confirmed that the shielding rate increased by about 4 percent as the internal pneumatic pressure increased from 0.2 bar to 0.3 bar. If we verify and further develop the results identified in this study through a real-size experiment, it will be able to be used as an effective waterproof measure for sudden water inflow into the undersea tunnels or underwater tunnels.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.666-672
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• 2024

In the present work, a new brick series based on the Vietnamese white clay minerals from the Bat Trang was fabricated to be applied in the radiation protection applications during the decommissioning of the nuclear power reactors. The bricks were constructed under various pressure rates varied from 7.61 MPa to 114.22 MPa. The influence of pressure rate on the physical and γ-ray shielding properties were investigated in the study. The experimental measurement for the material's density using the MH-300A density meter showed an enhancement in the prepared bricks' density by 22.5 % with increasing the applied pressure rate while the bricks' porosity reduced by 31.2 % when the pressure rate increased from 7.61 MPa to 114.22 MPa. The increase in the fabricated bricks density and the reduction in their porosities enhances the bricks' linear attenuation coefficients as measured by the NaI (Tl) detector along the energy range extended from 0.662 MeV to 1.332 MeV. The linear attenuation coefficient increased by 13.8 %, 17.6 %, 17.0 %, and 17.1 % at gamma ray energies of 0.662 MeV, 1.173 MeV, 1.252 MeV, and 1.332 MeV, respectively. The enhancement in the linear attenuation coefficient increases the bricks' radiation protection efficiency by 10.22 %, 14.48 %, 14.09 %, and 14.26 % at gamma ray energies of 0.662 MeV, 1.173 MeV, 1.252 MeV, and 1.332 MeV, respectively.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.847-852
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• 1995

A shielding analysis for KSC-7, the shipping cask for transporting the 7 PWR spent fuel assemblies, has been carried out. Radiation source term has been calculated on spent fuel with burnup of 50,000 MWD/MTU and 1.5 years cooling time by ORIGEN2 code. The shielding calculation for the cask has been made by using MCNP4A code with continuous cross section data library from ENDF/B-V. As a result of neutron dose rate analysis, another shielding calculational model on spent fuel shipping cask was provided which is using the Monte Carlo method.

• Nuclear Engineering and Technology
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• v.40 no.6
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• pp.511-516
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• 2008

Korea Hydro & Nuclear Power Co., Ltd. (KHNP) developed new IP-2 packages to transport low- and intermediate-level radioactive waste (LILW) steel drums from nuclear power plants to a disposal facility in accordance with IAEA and Korean transport regulations of radioactive material. Radiation shielding evaluation of the packages was carried out to demonstrate compliance with the regulatory requirements for IP-2 packages of radioactive material. Dose rate limits of LILW drums contained in the packages were determined.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.197-201
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• 1996

In the detail reaction-rate measurements in a critical assembly using the foil activation method, the measured activations of detector foils have inevitably errors caused by detector foil self-shielding effect. If neutron flux could be approximated to Westcott flux: i.e. well thermalized Maxwellian distribution, these activations of detector foil could be corrected to represent the unperturbated flux at any detected position in the cell with using Westcott option and reaction-rate option of the lattice code, WIMS-AECL. These calculated detector material self-shielding correction factors of the tested fuel, CANFLEX provided much information about neutron spectrum of test lattice cell as well as the correction factors themselves. The results could be verified by another lattice calculations.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.4
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• pp.166-171
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• 2005

Shielding methods on ELF(Extremely Low Frequency) magnetic fields may include the use of induced currents, modification of magnetic field flux patterns using high permeability and/or high conductivity materials, and others. The magnetic shielding properties of enclosures can be utilized to reduce the magnetic field of current carrying conductors. In this paper, to get a more practical understanding of shielding phenomena, we have investigated the magnetic field reduction by means of 3 dimensional numerical analysis and experiments. We found copper could reduce flux density more then permalloy in both cases of box shield and cylindrical shield. Iron under l0$\mu$T of 1 phase could reduce flux density about $20\%$ more than silicon steel, but both of them under 50$\mu$T has a similar reduction rate of $10\%$. The 3 phase horizontal model gave the highest reduction rate and the 1mm thickness iron under 10$\mu$T of 3 phase lines did lowest.

• The Korean Journal of Community Living Science
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• v.21 no.4
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• pp.595-603
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• 2010

The present study was performed on humans to investigate the physiological strain of wearing protective clothing for shielding electromagnetic waves and to compare control clothing that are currently on the market and new clothing that are developed for improving thermal comfort and material weight. Experiments were conducted in a climatic chamber of $28.8{\pm}0.6^{\circ}C$, $37{\pm}5%$RH under three differed experimental clothing conditions: None, Control, New. The results were as follows. Mean skin temperature and rectal temperature in New were significantly lower than that in None and Control (p<.05). The temperature and humidity inside clothing were lower in None (p<.05). Total weight loss was lower in New. Thermal sensation and thermal comfort were less hot and more comfortable in New than those in Control. It was concluded that wearing the protective clothing for shielding electromagnetic waves affects physiological responses such as distribution of body temperature, sweat rate, etc.