• Nuclear Engineering and Technology
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• 제50권5호
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• pp.806-813
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• 2018

$^{222}Rn$ exists in nature in the form of a rare radioactive gas. In terms of environmental radiation, issues regarding $^{222}Rn$ have persisted because of its radiological hazardousness. Ulju County is one of the regions of Ulsan metropolitan city, with a population of 227,699. Ulju County has the highest density of industrial complexes in Korea. In this study, $^{222}Rn$ radioactivity concentration was measured and analyzed in 57 schools in Ulju County using 114 passive LR-115 type detectors to secure radiological safety and confirm basic information for reduction of resident exposure to $^{222}Rn$. The effective dose of $^{222}Rn$ was assessed to find the actual risk of the concentration surveyed in schools to human beings. The dose depended on four factors: subjects, $^{222}Rn$ concentration, dose coefficient, and time. The individuals subjected to dose estimation were classified into three types: students, teachers, and office workers. The subjects had different dwelling locations and times. The findings demonstrate that the radiological hazard to students and workers at schools in Ulju County owing to $^{222}Rn$ is negligible in terms of $^{222}Rn$ activity recommendation level.

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1345-1356
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• 2021

Damage to nuclear power plants causes human casualties and environmental disasters. There are electrical facilities that control safety-related devices in nuclear power plants, and seismic performance is required for them. The 2016 Gyeongju earthquake had many high-frequency components. Therefore, there is a high possibility that an earthquake involving many high frequency components will occur in South Korea. As such, it is necessary to examine the safety of nuclear power plants against an earthquake with many high-frequency components. In this study, the shaking table test of electrical facilities was conducted against the design earthquake for nuclear power plants with a large low-frequency components and an earthquake with a large high-frequency components. The response characteristics of the earthquake with a large high-frequency components were identified by deriving the amplification factors of the response through the shaking table test. In addition, safety of electrical facility against the two aforementioned types of earthquakes with different seismic characteristics was confirmed through limit-state seismic tests. The electrical facility that was performed to the shaking table test in this study was a motor control center (MCC).

• Spatial Information Research
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• 제22권4호
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• pp.77-87
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• 2014

2014년 에콰도르의 툰구라와 화산폭발, 2010년 아이슬란드 에이야프야틀라이외쿠틀 화산폭발 등과 같이 최근 화산활동으로 인한 재해피해가 증가하고 있으며 이에 대한 대책마련이 시급한 실정이다. 본 연구에서는 현재 폭발 위험성이 높은 활화산 중 하나인 백두산을 대상으로 객관적 관측자료와 과학적인 방법에 근거하여 재해위험지역 분석을 실시하였다. 첫 번째로 중국학자 Liu Ruoxin의 연구에 근거하여 1215(${\pm}15$)년 백두산 화산 대폭발 화산재해 데이터를 참조하여 백두산지역의 지진관측자료와 화산지역 형태변화 관측자료, 화산지역 유체지구화학관측자료, 사회경제 통계데이터를 이용해 재해유발요소, 잠재적인 재해유발환경, 피해대상의 취약성을 종합적으로 평가하였다. 평가결과를 토대로 대상지역에 대한 백두산화산재해위험등급분포도를 산출하였으며, 그 결과 백두산화산재해위험등급을 4단계로 체계화하였다. 분석결과 백두산화산재해위험등급은 중심부에서 주변으로 갈수록 점차 등급이 낮아지는 것으로 분석되었으며 1,2급 위험지역은 화산폭발 시 위험도와 피해가 클 것으로 예상되는 고위험지역으로, 3,4급 위험 지역은 화산재해위험이 상대적으로 낮은 지역으로 나타났다. 또한 같은 강도의 화산재해요소의 작용하에서는 연구지역의 서쪽지역이 받는 위험성이 동쪽지역보다 높은데 이는 비교적 낮은 잠재적인 재해유발환경의 안정성과 높은 피해대상 취약성에 의해 결정됨을 확인할 수 있었다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권7호
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• pp.3545-3549
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• 2016

Background: The incidence of bladder cancer is lower in Asian than in Western countries. However, the crude incidence and mortality of bladder cancer have recently increased in Japan because of the increased number of senior citizens. We have already reported risk factors for urothelial cancer in a large population-based cohort study in Japan (JACC study). However, we did not evaluate the cancer risk in the upper and lower urinary tract separately in our previous study. Materials and Methods: Here we evaluated the risk of cancer death in the upper and lower urinary tracts, separately, using the database of the JACC study. The analytic cohort included 46,395 males and 64,190 females aged 40 to 79 years old. The Cox proportional hazard model was used to determine hazard ratios and their 95% confidence intervals. Results: Current smoking increased the risk of both upper and lower urinary tract cancer deaths. A history of kidney disease was associated with an increased risk of bladder cancer death, even after controlling for age, sex and smoking status. Conclusions: The present study confirmed that current smoking increases the risk of both upper and lower urinary tract cancer deaths and indicated the possibility that a history of kidney disease may be a risk factor for bladder cancer death in the Japanese population.

• 대한환경공학회지
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• 제37권11호
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• pp.619-630
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• 2015

본 연구는 국내 폐금속 광산에 특화된 인체위해성평가 방법을 제시하고, 두 폐금속 광산 지역에 시범적으로 적용하여 광산별 중금속 오염물질(As, Cd, Cu, Pb, Zn)에 대한 인체위해도를 정량적으로 산출하고자 수행되었다. 이를 위해 폐금속 광산에 적합한 7가지 노출경로 등의 노출시나리오를 설정하고, 폐금속 광산 지역 거주 주민의 특성에 맞는 노출인자를 추출하여 인체위해성평가에 활용하였다. 또한 최종적으로 얻어진 발암 및 비발암 위해특성을 광산별, 노출경로별, 오염물질별, 수용체별로 비교 분석하였다. 두 광산 모두에서 총 초과발암위해도가 허용 가능한 위해도인 $1{\times}10^{-6}$의 값보다 크게 나타나서 발암위해성이 있는 것으로 판명되었으며, 두 광산에서의 발암위해성은 유사한 것으로 조사되었다. 또한 두 광산 모두에서 성인에 대한 위험지수가 1보다 큰 값을 보여 비발암위해성이 있는 것으로 나타났고, 어린이의 경우에는 위험지수가 1보다 작은 값을 보여 상대적으로 비발암위해성이 낮은 것으로 조사되었다. 비발암위해성은 대정광산에서 봉광산보다 상대적으로 큰 것으로 나타났다. 그리고 발암 및 비발암위해성을 유발하는 주요한 노출경로는 농작물섭취와 지하수섭취로 평가되었다. 어린이의 경우에는 성인에 비해 상대적으로 표토섭취와 표토피부접촉 경로에 의한 발암 및 비발암 위해성이 큰 것으로 조사되었다. 오염물질별 위해성을 살펴보면, 발암위해성은 As, 비발암위해성은 As, Cd, Pb 등으로부터 주로 유발되어 As가 발암 및 비발위해성의 주요한 오염물질로 조사되었다.

• 한국지진공학회논문집
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• 제24권3호
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• pp.123-128
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• 2020

Analysis of the 2016 Gyeongju earthquake and the 2017 Pohang earthquake showed the characteristics of a typical high-frequency earthquake with many high-frequency components, short time strong motion duration, and large peak ground acceleration relative to the magnitude of the earthquake. Domestic nuclear power plants were designed and evaluated based on NRC's Regulatory Guide 1.60 design response spectrum, which had a great deal of energy in the low-frequency range. Therefore, nuclear power plants should carry out seismic verification and seismic performance evaluation of systems, structures, and components by reflecting the domestic characteristics of earthquakes. In this study, high-frequency amplification factors that can be used for seismic verification and seismic performance evaluation of nuclear power plant systems, structures, and equipment were analyzed. In order to analyze the high-frequency amplification factor, five sets of seismic time history were generated, which were matched with the uniform hazard response spectrum to reflect the characteristics of domestic earthquake motion. The nuclear power plant was subjected to seismic analysis for the construction of the Korean standard nuclear power plant, OPR1000, which is a reactor building, an auxiliary building assembly, a component cooling water heat exchanger building, and an essential service water building. Based on the results of the seismic analysis, a high-frequency amplification factor was derived upon the calculation of the floor response spectrum of the important locations of nuclear power plants. The high-frequency amplification factor can be effectively used for the seismic verification and seismic performance evaluation of electric equipment which are sensitive to high-frequency earthquakes.

• Molecular & Cellular Toxicology
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• 제1권2호
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• pp.73-77
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• 2005

Nickel is the one of potent environmental, the occupational pollutants and the classified human carcinogens. It is a serious hazard to human health, when the metal exposure. To prevent human diseases from the heavy metals, it is seemingly important that understanding of how nickel exerts their toxicity and carcinogenic effect at a molecular and a genomic level. The process of nickel absorption has been demonstrated as phagocytosis, iron channel and diffusion. Uptaked nickel has been suggested to induce carcinogenesis via two pathways, a direct DNA damaging pathway and an indirect DNA damaging pathway. The former was originated from the ability of metal to generate Reactive Oxygen Species (ROS) and the reactive intermediates to interact with DNA directly. Ni-generated ROS or Nickel itself, interacts with DNAs and histones to cause DNA damage and chromosomal abnormality. The latter was originated from an indirect DNA damage via inhibition of DNA repair, or condensation and methylation of DNA. Cells have ability to protect from the genotoxic stresses by changing gene expression. Microarray analysis of the cells treated with nickel or nickel compounds, show the specific altered gene expression profile. For example, HIF-I (Hypoxia-Inducible Factor I) and p53 were well known as transcription factors, which are upregulated in response to stress and activated by both soluble and insoluble nickel compounds. The induction of these important transcription factors exert potent selective pressure and leading to cell transformation. Genes of metallothionein and family of heat shock proteins which have been known to play role in protection and damage control, were also induced by nickel treatment. These gene expressions may give us a clue to understand of the carcinogenesis mechanism of nickel. Further discussions on molecular and genomic, are need in order to understand the specific mechanism of nickel toxicity and carcinogenicity.

• 농촌계획
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• 제11권2호
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• pp.9-19
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• 2005

The purpose of this study is to analyze the potential soil loss and hazard zone by the Revised Universal Soil Loss Equation(RUSLE) for preservation and management of land resources which is the base of ecosystem, and to grasp the relationship between RUSLE factors in the Nakdong River Basin. All thematic maps used in RUSLE are constructed through GIS and spatial analysis method derived from digital topographic maps, detailed soil maps, land-cover maps, and mean annual precipitation of 30 years collected respectively from National Geographic Information Institute, National Institute of Agricultural Science and Technology, and Ministry of Environment. The slope length of LS-factor that takes much times by the study area's wideness was calculated automatically through AML(Arc Macro Language) program developed by Van Remortel et al.(2001, 2003). The results are as follows; First, according to the soil loss estimation by the RUSLE, it shows that approximately 82% of the study area have relatively lower possibility of soil loss which is the 1 ton/ha in annual soil loss. While, 9.4% ($2,228km^2$) needed intensive and continuous management for soil loss. Because the amount of their annual soil loss was greater than 10 ton/ha that is optimum level suggested by Morgan(1995). For these areas, the author believe that a new approach which can minimize environmental impacts from soil loss through improvement of cultivation process and buffer forest zone should be applied. Second, according to the relationship between the RUSLE factors, topographical(LS-factor) and cover management(C-factor) conditions have a lot of influence on soil loss in case of the Nakdong River Basin. However, because of RUSLE factor's influence that affect to soil loss might be different based on the variety of spatial hierarchy and extent, it is necessary to analyze and evaluate factor's relationship in terms of spatial hierarchy and extent through field observations and further studies.

• 대한원격탐사학회지
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• 제36권1호
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• pp.67-81
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• 2020

The rapid climatic changes being caused by global warming are resulting in abnormal weather conditions worldwide, which in some regions have increased the frequency of landslides. This study was aimed to analyze and compare the landslide susceptibility using the Frequency Ratio (FR), Statistical Index, Weight of Evidence, Certainty Factor, and Index of Entropy (IoE) at Woomyeon Mountain in South Korea. Through the construction of a landslide inventory map, 164 landslide locations in total were found, of which 50 (30%) were reserved to validate the model after 114 (70%) had been chosen at random for model training. The sixteen landslide conditioning factors related to topography, hydrology, pedology, and forestry factors were considered. The results were evaluated and compared using relative operating characteristic curve and the statistical indexes. From the analysis, it was shown that the FR and IoE models were better than the other models. The FR model, with a prediction rate of 0.805, performed slightly better than the IoE model with a prediction rate of 0.798. These models had the same sensitivity values of 0.940. The IoE model gave a specific value of 0.329 and an accuracy value of 0.710, which outperforms the FR model which gave 0.276 and 0.680, respectively, to predict the spatial landslide in the study area. The generated landslide susceptibility maps can be useful for disaster and land use planning.

• 한국정보통신학회논문지
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• 제23권1호
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• pp.90-96
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• 2019

최근 실험실에서 사용하는 시약장은 IoT 기반 다양한 센서들을 활용하여 내부 환경을 실시간으로 측정하고 사용자들에게 서비스를 제공한다. 센서 데이터를 수집한 후 서버 내에서 위험상황을 식별하고 기기들에게 동작 명령을 전송하게 된다. 이와 같은 중앙 집중형 관리시스템은 여러 대의 시약장에서 측정되는 센서 데이터들을 전송받고 처리하게 될 경우 시약장의 수가 증가할 때마다 데이터 처리 속도가 점차 증가하게 되는 문제가 발생할 수 있다. 이를 해결하기 위해 본 논문에서는 중앙 집중형이 아닌 분산 환경에서 시약장 내부 환경을 분석하여 위험상황의 식별 및 기기 제어를 수행할 수 있는 분산 제어가 가능한 분산 IoT 센서 기반 실험실 안전관리 시스템에 대해 연구한다. 이와 같이 분산형 제어가 가능한 센서 모듈을 이용한 시약장 내부 환경 제어 통해 위험상황에 대한 식별 및 대처를 자동으로 진행함으로써 기존의 시약장과 실험실을 관리하는 시스템들보다 신속한 대처 및 안전관리가 이루어졌음을 확인하였다.