• Journal of Radiation Protection and Research
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• 제41권3호
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• pp.291-300
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• 2016

Background: It is necessary to assess radiation dose to workers due to inhalation of airborne particulates containing naturally occurring radioactive materials (NORM) to ensure radiological safety required by the Natural Radiation Safety Management Act. The objective of this study is to develop an internal dose assessment procedure for workers at industries using raw materials containing natural radionuclides. Materials and Methods: The dose assessment procedure was developed based on harmonization, accuracy, and proportionality. The procedure includes determination of dose assessment necessity, preliminary dose estimation, airborne particulate sampling and characterization, and detailed assessment of radiation dose. Results and Discussion: The developed dose assessment procedure is as follows. Radioactivity concentration criteria to determine dose assessment necessity are $10Bq{\cdot}g^{-1}$ for $^{40}K$ and $1Bq{\cdot}g^{-1}$ for the other natural radionuclides. The preliminary dose estimation is performed using annual limit on intake (ALI). The estimated doses are classified into 3 groups ( < 0.1 mSv, 0.1-0.3 mSv, and > 0.3 mSv). Air sampling methods are determined based on the dose estimates. Detailed dose assessment is performed using air sampling and particulate characterization. The final dose results are classified into 4 different levels ( < 0.1 mSv, 0.1-0.3 mSv, 0.3-1 mSv, and > 1 mSv). Proper radiation protection measures are suggested according to the dose level. The developed dose assessment procedure was applied for NORM industries in Korea, including coal combustion, phosphate processing, and monazite handing facilities. Conclusion: The developed procedure provides consistent dose assessment results and contributes to the establishment of optimization of radiological protection in NORM industries.

• Asian Pacific Journal of Cancer Prevention
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• 제15권15호
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• pp.6161-6164
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• 2014

Background: We have reported the radiation could activate STAT3, which subsequently promotes the invasion of A549 cells. We here explored the dose- and time-response of STAT3 to radiation and the effect of radiation on upstream signaling molecules. Materials and Methods: A549 cells were irradiated with different doses of ${\gamma}$-rays. The expression of and nucleus translocation of p-STAT3 in A549 cells were detected by immunoblotting and immunofluorescence, respectively. The level of phosphorylated EGFR was also assessed by immunoblotting, and IL-6 expression was detected by real time PCR and ELISA. Results: Radiation promoted the phosphorylation of STAT3 at Y705 in a dose- and time-dependent manner and nuclear translocation. The level of phosphorylated EGFR in A549 cells increased after radiation. In additional, the mRNA and protein levels of IL-6 in A549 cells were also up regulated by radiation. Conclusions: STAT3 is activated by radiation in a dose-and time-dependent manner, probably due to radiation-induced activation of EGFR or secretion of IL-6 in A549 cells.

• 한국엔터테인먼트산업학회논문지
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• 제14권7호
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• pp.571-579
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• 2020

응급구조(학)과 학생들의 방사선 방어에 관한 지식, 태도 및 교육요구도를 조사하고 분석하여 방사선 방어를 위한 안전관리의 교육과정 프로그램 개발에 기초자료를 제공하기 위해 시행되었다. 연구대상자 244명을 분석한 결과 방사선 방어에 대한 지식 점수는 9.50점, 방사선 방어 태도 점수는 30.24점이었다. 방사선 방어에 대한 지식과 태도 모두 방사선 방어 교육을 받은 군이 받지 않은 군에 비해 통계학적으로 유의하게 높았고, 지식과 태도 간의 상관관계에서는 방사선 방어에 대한 태도 점수와 지식 점수와는 양의 상관관계를 보여(r=.472, p<.000), 응급구조(학)과 학생들의 지식 점수가 높아질수록 태도 점수가 높아진다는 것을 알 수 있었다. 방사선 방어 교육을 받은 대상자는 6.1%, 교육요구는 87.3%, 참여 의향은 82.0%, 교육시기는 2학년이 54.9%로 가장 높았다. 교육방법은 시청각 교재를 활용한 강의가 59.04%로 가장높았고, 강연자는 방사선사가 77.45%로 가장 높았다. 이 결과로부터 응급구조(학)과 학생들의 방사선 방어에 대한 지식 점수와 태도 점수가 낮음에도 불구하고 교육요구와 참여 의도가 높음을 알 수 있었고 교육효과를 높이기 위해서는 방사선사가 시청각 교재를 활용하여 교육을 실시하는 것이 가장 효과적이라는 결론을 얻었다.

• 한국콘텐츠학회논문지
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• 제16권10호
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• pp.563-572
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• 2016

본 연구는 간호학생과 간호사를 대상으로 방사선 방어에 대한 지식, 태도와 교육 요구를 조사하여 방사선 방어에 대한 중요성을 인지하도록 하고, 나아가 방사선 방어를 위한 안전관리의 효과적인 교육 프로그램 개발에 기초자료를 제공하고자 하였다. B광역시에 소재한 일 대학의 3, 4학년 간호학생(n=139)과 간호사(n=135) 총 274명을 대상으로 45문항의 설문지로 방사선 방어에 대한 지식, 태도, 교육 요구를 조사하였다. 그 결과 방사선 방어를 위한 안전관리 교육이 미흡한 실정이고, 이에 비해 교육요구와 참여의사는 매우 높으며, 방사선 방어에 대한 지식이 높을수록 방사선 방어에 대한 태도 또한 높아진다는 것을 알 수 있었다. 따라서 대상자의 교육 요구를 반영한 교육과정 개발이 매우 필요하며, 간호사의 외부교육 또는 병원 자체교육에서도 방사선 방어에 대한 프로그램의 운영이 필요하다고 볼 수 있다. 또한 교육 효과를 높이기 위하여 전문가를 통한 강연과 시청각 자료를 활용한 교육이 요구된다.

• Journal of Radiation Protection and Research
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• 제25권2호
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• pp.115-118
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• 2000

With reference to nuclear emergency information concerning the national emergency plan for nuclear accidents, the response plan for the atmospheric nuclear emergencies of the U.S. National Oceanic and Atmospheric Administration (NOAA) was reviewed and described for introducing an overview on it to the Korean Association for Radiation Protection (KARP).

• Journal of Radiation Protection and Research
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• 제35권4호
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• pp.167-171
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• 2010

Fixed radiation portal monitors (RPMs) deployed at border, seaport, airport and key traffic checkpoints have played an important role in preventing the illicit trafficking and transport of nuclear and radioactive materials. However, the RPM is usually large and heavy and can't easily be moved to different locations. These reasons motivate us to develop a mobile radiation detection system. The objective of this paper is to report our experience on developing the mobile radiation detection system for search and detection of nuclear and radioactive materials during road transport. Field tests to characterize the developed detection system were performed at various speeds and distances between the radioactive isotope (RI) transporting car and the measurement car. Results of measurements and detection limits of our system are described in this paper. The mobile radiation detection system developed should contribute to defending public's health and safety and the environment against nuclear and radiological terrorism by detecting nuclear or radioactive material hidden illegally in a vehicle.

• Journal of Radiation Protection and Research
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• 제41권3호
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• pp.310-314
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• 2016

Background: FCTC10 container is designed to transport $^{60}Co$ radioactive sources used in irradiation industry. It belongs to Type B(U) Category III (yellow) package when being loaded with a $^{60}Co$ source of $1.8{\times}10^5$ Ci. Materials and Methods: The container is constituted of shielding container, basket, protective cover and bracket. Shielding ability is provided mainly by stainless steel shells, tungsten alloy and lead among steel shells. Radiation level around the container has been calculated with both Monte Carlo simulations and measurements. Results and Discussion: It is proven that the shielding performance of the container fulfills the requirements in GB11806-2004 (Regulations for the safe transport of radioactive material, China Standard Press). Exposure doses to workers and to critical groups of public were calculated based on hypothetical exposure scene according to transport practice experience. Conclusion: The results show that doses to workers and public are less than the constraint dose considered in design, and the radiation level would be increased less than a factor of 2 under design basis accidents.

• Journal of Radiation Protection and Research
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• 제41권2호
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• pp.117-121
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• 2016

Background: Definition and grouping of initiating events (IEs) are important basics for probabilistic safety assessment (PSA). An IE in a spent fuel reprocessing plant (SFRP) is an event that probably leads to the release of dangerous material to jeopardize workers, public and environment. The main difference between SFRPs and nuclear power plants (NPPs) is that hazard materials spread diffusely in a SFRP and radioactive material is just one kind of hazard material. Materials and Methods: Since the research on IEs for NPPs is in-depth around the world, there are several general methods to identify IEs: reference of lists in existence, review of experience feedback, qualitative analysis method, and deductive analysis method. While failure mode and effect analysis (FMEA) is an important qualitative analysis method, master logic diagram (MLD) method is the deductive analysis method. IE identification in SFRPs should be consulted with the experience of NPPs, however the differences between SFRPs and NPPs should be considered seriously. Results and Discussion: The plutonium uranium reduction extraction (Purex) process is adopted by the technics in a model reprocessing plant. The first extraction cycle (FEC) is the pivotal process in the Purex process. Whether the FEC can function safely and steadily would directly influence the production process of the whole plant-production quality. Important facilities of the FEC are installed in the equipment cells (ECs). In this work, IEs in the FEC process were identified and categorized by FMEA and MLD two methods, based on the fact that ECs are containments in the plant. Conclusion: The results show that only two ECs in the FEC do not need to be concerned particularly with safety problems, and criticality, fire and red oil explosion are IEs which should be emphatically analyzed. The results are accordant with the references.

• 한국방사선학회논문지
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• 제11권4호
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• pp.189-195
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• 2017

방사선 특히, 엑스선 또는 감마선으로부터 인체를 보호하기 위해 납(Pb)으로 된 보호 장구를 광범위하게 사용해왔다. 최근 납 중독 및 환경오염의 문제로 납을 대신하는 무연 방사선 차폐재의 개발이 활발히 이루어지고 있다. 차폐재의 성능 확보를 위해서는 제작 및 평가의 순환 사이클을 반복하게 된다. 본 연구는 실제 무연 방사선 차폐소재의 제작에 앞서 차폐재의 성능을 몬테카를로 전산모사를 통해 확인함으로써 가능한 차폐소재의 조합을 연구하였다. 방사선 차폐소재의 평가에 사용되는 조건으로 엑스선관을 Geant4를 이용하여 전산모사하고 획득된 광자 스펙트럼을 이용하여 텅스텐과 비스무스의 조합에 따른 차폐소재의 성능을 평가하였다. 차폐소재의 공극에 따른 성능 저하도 평가하였다. 방사선 차폐 소재 개발 시 공극률을 줄이는 것이 중요한 인자라는 것을 알 수 있었다.

• Journal of Radiation Protection and Research
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• 제48권4호
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• pp.184-196
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• 2023

Background: Radiation protection is crucial in various fields due to the harmful effects of radiation. Shielding is used to reduce radiation exposure, but gamma radiation poses challenges due to its high energy and penetration capabilities. Materials and Methods: This work investigates the radiation shielding properties of polyvinylidene fluoride (PVDF) samples containing different weight fraction of tungsten carbide (WC), tungsten trioxide (WO₃), and tungsten disulfide (WS₂). Parameters such as the mass attenuation coefficient (MAC), half-value layer (HVL), mean free path (MFP), effective atomic number (Z_eff), and macroscopic effective removal cross-section for fast neutrons (Σ_R) were calculated using the Phy-X/PSD software. EpiXS simulations were conducted for MAC validation. Results and Discussion: Increasing the weight fraction of the additives resulted in higher MAC values, indicating improved radiation shielding. PVDF-xWC showed the highest percentage increase in MAC values. MFP results indicated that PVDF-0.20WC has the lowest values, suggesting superior shielding properties compared to PVDF-0.20WO₃ and PVDF-0.20WS₂. PVDF-0.20WC also exhibited the highest Z_eff values, while PVDF-0.20WS₂ showed a slightly higher increase in Z_eff at energies of 0.662 and 1.333 MeV. PVDF-0.20WC has demonstrated the highest Σ_R value, indicating effective shielding against fast neutrons, while PVDF-0.20WS₂ had the lowest Σ_R value. The Monte Carlo N-Particle Transport version 5 (MCNP5) simulations showed that PVDF-xWC attenuates gamma radiation more than pure PVDF, significantly decreasing the dose equivalent rate. Conclusion: Overall, this research provides insights into the radiation shielding properties of PVDF mixtures, with PVDF-xWC showing the most promising results.