• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 춘계 학술대회
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• pp.21-29
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• 2005

30 MW의 연구용 원자로인 하나로는 1995년 2월 초임계에 도달한 이후, 정상적으로 가동하고 있다. 가동 후 약 10년이 경과하여 1차 냉각펌프를 분해 점검하기 위해 펌프에 대한 화학제염이 2004년에 수행되었다. 제염을 수행하기 이전에 4개의 point를 설정하여 방사선량율 및 표면오염도를 측정하였고, 최종제염이 수행된 이후 같은 point에 대하여 방사선량율 및 표면오염도를 재측정 하였다. 펌프 외부는 노출되어 있어 쉽게 제염할 수 있으나 케이싱 내부에는 2중 볼류트가 있어 접근이 용이하지 않았다. 이를 제염하기 위하여 제염장치를 개발하였다. 이 장치는 일정 농도의 제염제 (DX-300)를 케이싱 내부에 담아 밀폐시킨 후 펌프의 임펠러를 저속으로 회전함으로서 제염제가 순환된다. 제염제의 유화작용에 의해 표면의 입자성 방사선 물질이 이완되고, 화학 작용에 의해 부식력과 용해성으로 표면 오염이 제거된다. 이 장치를 이용하여 하나로 1차 냉각펌프의 케이싱 내부를 제염하였다. 그 결과 1차 냉각펌프의 케이싱 내부는 반출허용표면오염도 이하로 낮출 수 있어 성공적으로 제염할 수 있었다.

• 대한환경공학회지
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• 제37권5호
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• pp.277-284
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• 2015

대청호의 추소수역과 추동수역에서 채취한 퇴적물의 오염도를 평가하기 위하여, 퇴적물의 입도, 유기물 및 영양염류의 농도와 인의 성상별 분석을 수행하였다. 소옥천의 영향을 받는 추소수역의 상류에 비해 추소수역에서 본류로 유입되는 지점과 추동수역의 퇴적물에서 실트 크기 입자의 평균 비율이 92%로 매우 높았다. 추소수역과 추동수역에서 퇴적물 중 총인의 농도는 각각 999 (${\pm}98$)과 1,123 (${\pm}119$) mg/kg sediment로 추동수역에서 상대적으로 높았다. 퇴적물 중 인의 성상분석 결과 외부 기원성 인보다 환경 조건 변화에 의해 쉽게 용출이 되는 것으로 알려진 내부 기원성 인의 비율이 높게 측정되어 이들 지점의 부영양화에 내부부하가 중요한 것으로 판단되었다. 퇴적물 중 총질소의 농도는 모든 시료에서 환경부의 하천 호소 퇴적물 오염평가 기준인 5,600 mg/kg sediment를 초과하여, 퇴적물의 총질소 오염도가 심각한 것으로 판단되었다. 이러한 결과로부터 대청호의 수질 개선을 위해 퇴적물에 대한 관리 대책이 필요한 것으로 판단된다.

• 한국동물위생학회지
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• 제26권1호
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• pp.27-31
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• 2003

In order to monitoring the chicken meat hygiene, 165 chicken samples were tested for contamination agents such as the total bacterial counts, coliform bacterial counts and falling bacterial counts. The prevalence of level on number of standard plate count(SPC), total bacterial counts in less than 10$^3$cfu/$\textrm{cm}^2$, 10$^3$∼10$^4$cfu/$\textrm{cm}^2$ and 10$^4$∼10$\^$5/cfu/$\textrm{cm}^2$ were 30 samples (18.2%), 98 samples(59.4%) and 37 samples(22.4%), respectively. The coliform bacterial counts in less than 10$^2$cfu/$\textrm{cm}^2$, 10$^2$∼10$^3$cfu/$\textrm{cm}^2$ and 10$^3$∼10$^4$cfu/$\textrm{cm}^2$ were 7 samples(4.2%), 66 samples (40.0%), 92 samples(55.8%), respectively. The falling bacterial counts in plants were higher 9.1, in summer 8.4, in fall 7.2 in spring and 6.7 in winter decreased.

• Fisheries and Aquatic Sciences
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• 제18권3호
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• pp.235-240
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• 2015

Seasonal variation in the prevalence of norovirus in oysters Crassostrea gigas was investigated and compared to levels of Escherichia coli, a fecal indicator in oysters. Oysters were collected from Iwon-myeon, Taean-gun, Korea, a primary production area for European Union export of oysters between 2013 and 2014. We observed seasonality in the prevalence of norovirus in oysters, with a higher prevalence and viral load detected during winter months. Oysters taken from production areas that complied with the European Union standard for raw consumption (< 230 MPN/100 g of E. coli) had 22.1% of the samples test positive for norovirus (15/68 samples). However, norovirus was not detected in any of the samples (0%, 0/4 samples) that were collected from production sites that exceeded the standard fecal contamination level for raw consumption (> 230 MPN/100 g of E. coli). These results indicated that there is a negative correlation between the prevalence of norovirus and high levels of E. coli in oysters. Therefore, our results suggest that current food safety guidelines using only a bacterial fecal contamination indicator, E. coli, may not adequately assess shellfish production areas for viral and bacterial contamination.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권1호
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• pp.19-28
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• 2010

Considering six screen matrix to select an optimum remediation method for the Kunsan military base contaminated with petroleum oil, the following order was obtained: landfarming > biopile > soil washing > thermal desorption = incineration. When the landfarming method was applied for the remediation of 2,250 $m^3$ soil contaminated with petroleum oil ranging from 500 to 2,404 mg/kg as TPH, contamination level decreased below target concentration 450 mg/kg after 20~42 days depending on the initial contamination. From the evaluation of case studies of landfarming, it is suggested that ratty-truss or single-arch structure is suitable in the landfarming plant for the treatment of large-scale contaminated soil requiring long period of remediation. But, vinyl-house structure is suitable in the landfarming plant for the treatment of small-scale contaminated soil requiring short period of remediation. Therefore vinyl-house structure is recommended in the remediation of contaminated soil less than 5,000 $m^3$ requiring within 1 year of remediation period but ratty-truss or single-arch structure is recommended for the remediation of contaminated soil more than 5,000 $m^3$.

• Food Science and Biotechnology
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• 제15권6호
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• pp.920-924
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• 2006

The microbiological safety of foodservice facilities and side dishes in 6 elementary schools and 6 universities in the Jeolla-do region was evaluated. The micro-aerosol evaluation of foodservice facilities including the kitchen, refrigerators, and freezers showed a comparatively high level of microbial contamination. In the microbial safety evaluation of cooking utensils and appliances, the total plate counts of serving tables, cutting boards, and food plates were comparatively high, but did not reveal significant counts of coliforms, Staphylococcus aureus, and Escherichia coli were both below the general limit of microbial contamination. The microbiological safety of the cooking utensils and appliances were satisfactory. In the microbiological safety evaluation of side dishes served at these foodservice facilities, microbial counts were generally below the limit of microbial contamination.

• 한국과학교육학회지
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• 제19권4호
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• pp.585-594
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• 1999

The purpose of this study is to examine the concept of Greenhouse Effect as understood by middle school high school university students using a closed-form questionnaire. Based on results of the questionnaire which was administered to 619, the extent to which alternative concepts were held was quantified and compared the difference of various group based on grade level. gender, text and major. Also, subjects were divided into two groups, one is middle school students and the other is high school university students and common themes within conceptual framework of each group were identified by factor analysis. The result showed that students confused Greenhouse Effect with ozone layer depletion in stratosphere and linked familiar contamination around everyday life. acid rain. radioactive contamination, nuclear arsenal to Greenhouse Effect. These trends were more appreciable in female than male, biology major than any other major and text did not make any significant difference. In addition, the result of factor analysis showed that two groups linked familiar contamination around everyday life to Greenhouse Effect and high school university students understand the consequences of an increase in the Greenhouse Effect more systematically than middle school student, perceived the relation between the origin of an increase in the Greenhouse Effect and human activity but confused Greenhouse Effect with ozone layer depletion in stratosphere.

• Environmental Analysis Health and Toxicology
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• 제19권1호
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• pp.1-24
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• 2004

Since dioxins became a serious concern in Korea, a significant number of investigations have been conducted to address diverse issues related to dioxins. However, the results have not been organized for ready access and use. The principal purposes of the work were to ⅰ) provide an archive of dioxin researches in Korea and ⅱ) give an overview of dioxin contamination. The focus of this work was placed on the contamination levels and characteristics concerning the waste incinerators emissions, environmental media, and biological samples(fishes/shellfishes, foods, and human body). Principal component analysis was conducted to identify common and/or unique features and the important variables associated with the congener patterns. From a comprehensive search of academic journals, research and monitoring project reports, dissertations, and periodicals of other forms, a total of 115 counts were found that met the purposes of this study. The contamination levels of various samples were summarized and compared to those reported in foreign literatures. The congener patterns varied largely with environmental media and distinguished particularly by OCDD, 1,2,3,4,6,7,8-HpCDF, and OCDF for the samples within the same media. The proximity to emission sources differentiated the congener patterns in air and soil samples by the fraction of OCDD.

• 한국동물위생학회지
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• 제26권3호
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• pp.221-225
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• 2003

In order to monitoring the chicken meat hygiene, 165 chicken samples were tested for contamination agents such as the total bacterial counts, coliform bacterial counts and falling bacterial counts. The prevalence of level on number of standard plate count, total bacterial counts in less than $10^3\;cfu/cm^2$, $10^3{\sim}10^4\;cfu/cm^2$ and $10^3-10^5\;cfu/cm^2$ was 30 samples(18.2%), 98 samples(59.4%) and 37 samples(22.4%), respectively. The coliform bacterial counts in less than $10^2\;cfu/cm^2$, $10^2{\sima}10^$\;cfu/cm^2$ and $10^3{\sim}10^4\;cfu/cm^2$ was 7 samples(42.2%), 66 samples(40.0%), 92 samples(58.8%), respectively. The falling bacterial counts in plants was higher 9.1 in summer, 8.4 in fall, 7.2 in spring and 6.7 in winter, in order.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.207-210
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• 1998

Surface electrical conduction in insulator is most important factor to assess the insulation performances of outdoor insulating materials. In this paper, contamination performance of the widely used materials for outdoor insulator - porcelain, EPDM, Silicone rubber - were discussed by measuring properties of average leakage current and scintillation discharge pulses under artificial contamination conditions. The artificial contaminations used were deionized distilled water fog, 0.5wt% NaCl salt fog of light pollution and 2wt% NaCl salt fog of medium pollution. The average leakage current was appeared linearly with applied voltage at dry and clean surface condition. The magnitude of leakage current was almost same at different kinds of samples. In case of deionized distilled water fog, the characteristics of leakage current and applied voltage was most different to that in case of dry and clean condition. In case of salt fog pollution condition. The leakage current was increased above critical voltage. The scintillation discharges were also activated at the level the leakage current and scintillation discharges were increased with increasing pollution degree. The resistance to pollution properties of silicone rubber appeared excellent among them.