• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.80-90
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• 1993

Radiation streaming through penetrations has been of great concern in radiation shielding design and analysis. This study developed a Monte Carlo method and constructed a data library of results calculated by the Monte Carlo method for radiation streaming through a straight cylindrical duct in concrete walls of a broad, mono-directional, mono-energetic gamma-ray beam of unit intensity. It was demonstrated that average dose rate due to an isotropic point source at arbitrary positions can be well approximated using the library with acceptable error. Thus, the library can be used for efficient analysis of radiation streaming due to arbitrary distributions of gamma-ray sources.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.11a
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• pp.299-302
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• 2006

연구로 및 원자력 시설의 해체 공정 절차 수립과 해체 시나리오 선정에 기초 자료를 제공하고자 컴퓨터 그래픽스를 응용한 방사화 분포 가시화 연구가 수행되었다. 해체 전 시료 채취와 핵종 분석을 통해 방사능 자료가 확보된 연구로 2 호기 조사실(Exposure Room)과 조사실 주변의 콘크리트 차폐체(Concrete Shielding)를 대상으로 방사화 분포 가시화 실험이 이루어졌다. $^{60}Co$에 오염된 조사실의 벽면과 콘크리트 차폐체의 깊이 별로 조사된 방사능 농도 값을 기초로하여 이들 구조물을 3 차원으로 모델링 한 후 Contour mapping을 수행하여 방사화 분포 가시화를 완료하였다. 방사능 정도를 가시화 한 결과와 콘크리트 차폐체 깊이에 따라 지수 함수적으로 감소하고 있었던 결과가 잘 일치하고 있음을 확인할 수 있었다. 연구 결과 자료는 향후 해체 활동 중 방사선에 노출되는 작업자의 피폭선량 평가 모델에 중요한 역할을 수행할 것이다.

• Journal of radiological science and technology
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• v.41 no.6
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• pp.581-586
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• 2018

This study was conducted to analyze factors Influencing Protective Behavior against Radiation Exposure using questionnaires for 231 radiological technologists working in Computed Tomography(CT) examination room with high radiation dose in diagnostic radiology field. Statistical analysis of the collected data revealed that the reasons for partially shielding the examination part in the CT scan were the lack of protective equipment, securing of radiation justification, being annoying and maybe not being harm to adults in order. It was also revealed that the variables influencing the protective behavior were protective behavior against radiation harm, self-efficacy, protective environment, organization culture, protective knowledge and protective instrument in order. The higher the radiological protective environment(${\beta}=0.245$) and the lower the radiological protective knowledge(${\beta}=-0.034$), the more influential the protective behavior against radiation harm was. In this study, it was shown that non examination parts were not shielded in the CT scan. Therefore, it is necessary to improve the level of protective environment, to cultivate knowledge to improve the protective behavior against radiation harm and to have an intervention strategy for concrete action.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.827-833
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• 2023

CT(Computed Tomography) contrast agents are commonly used in general hospitals and university hospitals when taking radiographic examinations. The CT contrast medium contains a mixture of a substance called "Iodine", which absorbs radiation energy and makes it appear white in the CT image, further improving the image quality. In addition, the CT contrast agent, which moves like blood in the blood vessels, clearly differentiates it from muscle and water, so CT contrast agents are widely used in hospitals. These CT contrast agents absorb X-rays, but in order to absorb X-rays, they must have a high density or a high radiation absorption coefficient. Since the CT contrast agent is injected into the blood vessels, if the density is high, the blood vessels are strained and the patient is in shock. For this reason, it is necessary to match the density similar to that of water and always pay attention to side effects. In addition, the amount of CT contrast medium is adjusted according to the patient's body shape, and the remaining contrast medium is discarded. However, This study tried to find out the idea of recycling it as a radiation shielding material. Since the CT contrast medium has a high radiation absorption coefficient at a density similar to that of water, the amount to absorb radiation is adjusted, the amount of contrast medium and the amount of water are adjusted, and the amount of radiation absorbed is determined by mixing with water. In addition, a study was conducted to find out the result of the difference in radiation absorption in various ways by comparing the radiation quality coefficient and absorption coefficient with other substances or materials in an environmentally friendly method harmless to the human body by mixing CT contrast medium and water.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1431-1438
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• 2022

In this study, natural radioactivity concentrations and dosimetric values of fly ash samples were evaluated for the landfill area of the coal-fired power plant (CFPP) complex at Binh Thuan, Vietnam. The average activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were 93, 77, 92 and 938 Bq kg^-1, respectively. The average results for radon dose, indoor external, internal, and total effective dose equivalent (TEDE) were 5.27, 1.22, 0.16, and 6.65 mSv y^-1, respectively. The average emanation fraction for fly ash were 0.028. The excess lifetime cancer risks (ELCR) were recorded as 20.30×10^-3, 4.26×10^-3, 0.62×10^-3, and 25.61×10^-3 for radon, indoor, outdoor exposures, and total ELCR, respectively. The results indicated that the cover of shielding materials above the landfill area significantly decreased the gamma radiation from the ash and slag in the ascending order: Zeolite < PVC < Soil < Concrete. Total dose of all radionuclides in the landfill site reached its peak at 19.8 years. The obtained data are useful for evaluation of radiation safety when fly ash is used for building material as well as the radiation risk and the overload of the landfill area from operation of these plants for population and workers.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.593-604
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• 2021

In this study, a comparative test was conducted on a specially developed elastic waterproof paint and general water-based paint for the purpose of responding to cracks occurring on the outer wall of concrete structures and improving watertightness. Through the comparative experiment, it was confirmed that the watertightness could be improved by securing the crack shielding property, and it was also confirmed that about 10 times more crack responsiveness was secured compared to general water-based paint. In addition, it was confirmed that the adhesion performance of at least 1.3MPa and resistance to a water permeation pressure of 0.1MPa were possible, confirming that stability was secured from a waterproofing perspective.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.1
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• pp.1-8
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• 2023

At construction sites, interest in the production of precast materials is increasing due to off-site conditions due to changes in construction site conditions due to increased labor costs and the Act on the Punishment of Serious Accidents. In particular, the precast prestressed hollow slab has a hollow shape in the cross section, so structural performance is secured by reducing weight and controlling deflection through stranded wires. With the application of structural standards, the urgency of securing fire resistance performance is emerging. In this study, a fire-resistance cross section was developed by reducing the concrete filling rate in the cross section and improving the upper and lower flange shapes by optimizing the hollow shape in the cross section of the slab to have the same or better structural performance and economic efficiency compared to the existing hollow slab. The PC hollow slab to which this was applied was subjected to a two-hour fire resistance test using the cross-sectional thickness as a variable, and as a result of the test, fire resistance performance (load bearing capacity, heat shielding property, flame retardance property) was secured. Based on the experimental results, it is determined that fire resistance modeling can be established through numerical analysis simulation, and prediction of fire resistance analysis is possible according to the change of the cross-sectional shape in the future.