• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1210-1216
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• 2018

Site or multi-unit (MU) risk assessment has been a major issue in the field of nuclear safety study since the Fukushima accident in 2011. There have been few methods or experiences for MU risk assessment because the Fukushima accident was the first real MU accident and before the accident, there was little expectation of the possibility that an MU accident will occur. In addition to the lack of experience of MU risk assessment, since an MU nuclear power plant site is usually very complex to analyze as a whole, it was considered that a systematic method such as probabilistic safety assessment (PSA) is difficult to apply to MU risk assessment. This paper proposes a new MU risk assessment methodology by using the conventional PSA methodology which is widely used in nuclear power plant risk assessment. The logical failure structure of a site with multiple units is suggested from the definition of site risk, and a decomposition method is applied to identify specific MU failure scenarios.

• 대한토목학회논문집
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• 제28권4B호
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• pp.363-374
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• 2008

국내에서 수공구조물의 설계를 위한 확률강우량을 산정하기 위해서 널리 사용되는 강우강도식은 주로 회귀분석을 적용한 형태가 일반적이지만, 본 연구에서는 각 지점별 적정확률분포형의 누가분포함수를 활용하여 강우강도식의 형태를 결정하고, 매개변수는 유전자알고리즘을 적용하여 추정하는 강우강도식을 제안하고자 한다. 기존에 사용하던 강우강도식과의 정확도 비교를 위하여 기상청 22개 지점에 대한 재현기간, 지속기간별 평균제곱근오차, 평균제곱근 상대오차를 검토한 결과 누가분포함수를 활용한 강우강도식이 더 높은 정확도를 가짐을 보였으며, 또한, 최근의 집중호우에 대한 영향을 살펴보기 위하여 2006년 까지의 강우자료를 이용하여 기존의 회귀식에 의한 방법과 누가분포함수를 활용한 경우의 결과값을 비교한 결과 이 경우에도 누가분포함수를 활용한 강우강도식의 정확도가 더 높음을 알 수 있었다. 결과적으로 본 연구에서 제안된 누가분포함수를 활용한 강우강도식은 기존의 회귀분석을 활용한 강우강도식보다 정확도면에서 우수하다고 할 수 있으며, 국내에 충분히 적용가능한 형태의 강우강도식이라고 판단된다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2007년도 추계 종합학술대회 논문집
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• pp.231-233
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• 2007

고에너지물리 e-Science 연구 환경 구축은 데이터가 생산되는 외국의 가속기 연구소에 가지 않더라도, 언제나 어디서나 실제 가속기 연구소에서 고에너지물리 연구를 수행하는 것과 같은 연구 환경을 만드는 것이다. 그 구성 요소로서 1) 데이터 생산, 2) 데이터 프로세싱, 3)데이터 publication이 있다. 데이터 생산은 원격 제어시스템을 활용하여 원격으로 데이터 생산에 참여하는 것이며 데이터 프로세싱은 그리드 팜을 활용하여 job을 언제나 어디서나 수행하는 것이며 데이터 publication은 EVO(Enabling Virtual Organzation) 시스템을 활용하여 공동 협업 환경으로 연구 결과물을 얻는 것이다. 이러한 개념을 고에너지물리 실험의 하나인 CDF 실험에 적용하여 구현하였다.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.498-508
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• 2021

Micro reactors are increasingly being considered for utilization as distributed power sources. Hence, the probabilistic safety assessment (PSA) of a direct supercritical-CO₂-cooled fast reactor, called micro modular reactor (MMR), was performed in this study; this reactor was developed using innovative design concepts. It adopted a modular design and passive safety systems to minimize site constraints. As the MMR is in its conceptual design phase, design weaknesses and valuable safety insights could be identified during PSA. Level 1 internal event PSA was carried out involving literature survey, system characterization, identification of initiating events, transient analyses, development of event trees and fault trees, and quantification. The initiating events and scenarios significantly contributing to core damage frequency (CDF) were determined to identify design weaknesses in MMR. The most significant initiating event category contributing to CDF was the transients with the power conversion system initially available category, owing to its relatively high occurrence frequency. Further, an importance analysis revealed that the safety of MMR can be significantly improved by improving the reliability of reactor trip and passive decay heat removal system operation. The findings presented in this paper are expected to contribute toward future applications of PSA for assessing unconventional nuclear reactors in their conceptual design phases.

• Nuclear Engineering and Technology
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• 제44권7호
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• pp.745-754
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• 2012

The correlations between Large Early Release Frequency (LERF) and Early Fatality need to be investigated for risk-informed application and regulation. In Regulatory Guide (RG) -1.174, while there are decision-making criteria using the measures of Core Damage Frequency (CDF) and LERF, there are no specific criteria on LERF. Since there are both huge uncertainties and large costs needed in off-site consequence calculation, a LERF assessment methodology needs to be developed, and its correlation factor needs to be identified, for risk-informed decision-making. A new method for estimating off-site consequence has been presented and performed for assessing health effects caused by radioisotopes released from severe accidents of nuclear power plants in this study. The MACCS2 code is used for validating the source term quantitatively regarding health effects, depending on the release characteristics of radioisotopes during severe accidents. This study developed a method for identifying correlations between LERF and Early Fatality and validates the results of the model using the MACCS2 code. The results of this study may contribute to defining LERF and finding a measure for risk-informed regulations and risk-informed decision-making.

• 대한골관절종양학회지
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• 제1권2호
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• pp.226-232
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• 1995

Survival rate of osteosarcoma has been improved recently due to the neoadjuvant and adjuvant chemotherapy. Limb-salvaging operation(LSO) has replaced the amputation technique without' lowering the survival rate. And there occurred a lot of patients who are suffering from the high cost of artificial implants and forced to choose amputation due to economic problem. In LSO, usually relatively high cost artifical implant is needed. When a patient and not afford such an expensive implant he had to choose an inexpensive way, amputation. Authors tried bone lengthening by adopting Ilizarov technique after wide resection of tumor in two patients. Bone transportation was successful in one patient and less successful in the other. One case in CDF(continuosly disease free since the surgical procedure) state at follow-up 3 year 4 months after knee joint fusion. And the other was given lobectomy for lung metastasis at postop. 1 year and 9 months, and given osteosynthesis for infected nonunion at the docking site. Bone transportation was thought to be a good method for the bony coverage of dead space caused by wide resection. Bone transportation technique was economical as well as biological We present two osteosarcoma patient who treated with Ilizarov bone transportation.

• 한국토양비료학회지
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• 제45권1호
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• pp.107-111
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• 2012

Eight marine sediments from Busan port in Korea were annually analyzed to examine the concentration distribution of dioxins from 2006 to 2010. Yearly mean concentration of dioxins ranged from 186.3 to $383.3pg\;g^{-1}$ in real values and 5.087 to 8.541 pg-TEQ (Toxicity equivalency) based on dry weight of samples. The dioxin concentration at the site near fishing market was the highest concentration among all sampling sites. Also the dioxin concentration at the sites with various pollutant sources such as large ships, sewage influx and thermal power station as well as fishing market was higher than that of the sites without specific pollutant sources. Another main factor that affects the dioxin concentration is topography characteristics of the bay. The bay has relatively high dioxin concentration because of the lack of the pollutant diffusion. This study demonstrated that the dioxin concentration in the site with pollutant sources and the lack of the pollutant diffusion was relatively high as compared with the other sites. As a result of contribution ratio of dioxin congeners, OCDD (Octachlorodibenzodioxin) in all sites was major contributor in real value, in contrast, dioxin congeners in TEQ values were dominated by 2,3,4,7,8-PeCDF.

• 환경생물
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• 제26권4호
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• pp.330-342
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• 2008

A comprehensive quality survey for PCDDs/PCDFs and coplanar PCBs as well as heavy metals (Cu, Zn, Cd and Pb) in sediments has been investigated in August 2006, Korea. Monitoring was undertaken at five streams representing different surrounding environments throughout Juwang and Gapyeong streams (reference sites), Jungrang stream (dense population site), Ansan stream (mixed small population and industrial site), and Siheung stream (heavy industrial site). The levels of heavy metal in samples were found to be significantly higher in sediment from Siheung stream compared to those of other stream sites. The heavy metal concentrations (dry weight basis) in sediment from Siheung stream were as follows; Cd (3.7 ${\mu}g$/g), Pb (1,295 ${\mu}g$/g), Cu (713.4 ${\mu}g$/g) and Zn (358.1 ${\mu}g$/g). Among 12 coplanar PCBs and 17 PCDDs/PCDFs selected as target compounds in this study, PCB (IUPAC no. 118) and OCDD were the most abundant congeners found in all sediment samples, followed by 1,2,3,4,6,7,8-HpCDD, OCDF and 1,2,3,4,6,7,8HpCDF as well as PCB (IUPAC no. 105). These results were shown to be in the same trend as the sediment samples of other countries. The levels of PCDDs/PCDFs/coplanar PCBs in sediment samples were expressed as concentrations and WHO- TEQ values. The PCDDs/PCDFs/coplanar PCBs concentrations and their WHO-TEQ values in sediment from Siheung stream were remarkably high. The levels detected were 788.16 pg/g and 36.080 pg WHO-TEQ/g dry weight for PCDDs/ PCDFs and 314 pg/g and 0.4189 pg WHO-TEQ/g dry weight for coplanar PCBs, respectively, beyond the safety level of sediment value 20 pg WHO-TEQ/g. Sediment samples of the five streams were also monitored by sensitive biomarkers using insect immune responses: hemocyte-spreading behavior and immune-associated enzyme activities of phospholipase A$_2$ (PLA$_2$) and phenoloxidase. Organic extracts of Siheung and Jungrang sediments significantly interfered with the hemocytespreading behavior, whereas those of Ansan, Gapyeong, and Juwang did not. These organic extracts did not inhibit the PLA$_2$ and phenoloxidase activities. However, phenoloxidase was highly susceptible to exposure to aqueous extracts in all site sediments. In comparison, PLA$_2$ activities of the hemocytes were significantly inhibited only by aqueous extracts of Siheung, Jungrang, and Gapyeong sediments, but not by those of Ansan and Juwang. Despite some disparity between bioand chemical monitoring results, the biomarkers can be recommended as a device warning the contamination of biohazard environmental chemicals because of a fast and inexpensive detection method.

• 한국도로학회논문집
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• 제8권3호
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• pp.29-37
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• 2006

본 연구는 현재 수행중인 "한국형 포장 설계법 개발과 포장성능 개선방안 연구"의 일환으로 역학-경험적 포장 설계법에 사용될 교통하중 입력변수를 정량화하기 위해서 실시하였다. 교통하중 정량화를 위하여 기존의 ESAL 개념이 아닌 축하중 스펙트럼을 이용하였다. 이를 위하여 교통량 통계 연보내 교통량 자료를 가지고 일반 국도에 대한 대표 축하중 조사지점을 차로별, 지역특성별 구분에 따라 33개 지점을 통계적 방법을 이용하여 선정하였다. 그리고 선정된 대표 지점을 대상으로 축하중 계측기를 이용하여 각 차종에 대한 축하중을 조사하였다. 측정된 축하중 자료는 각각 분류된 조건에 따라서 축하중 스펙트럼으로 표준화하였으며, 그 방법으로 누적밀도함수인 S-커브 곡선을 이용하여 각 조건별 계수를 제시하였다.

• 대한바이러스학회지
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• 제28권1호
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• pp.71-78
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• 1998

Vaccinia virus is the prototype orthopoxvirus that has been used as a vaccine strain for small pox. This virus has been used to express a variety of cellular and viral genes in mammalian cells at high levels. Interleukin-4 (IL-4) has been found to stimulate the proliferation of T cells and enhance the cytolytic activity of cytotoxic T lymphocytes. To test the immunotherapeutic potential of IL-4 delivered in vivo by poxvirus, a recombinant vaccinia virus expressing the murine IL-4 gene (RVVmIL-4) was constructed. A high level of IL-4 production was confirmed by infecting HeLa cells and measuring IL-4 in cell culture supernatant by ELISA. As a tumor model, two cell lines were used; the murine T leukemic line P388 and the murine breast cancer line TS/A. CDF1 mice were intraperitoneally inoculated with $1\;{\times}\;10^5$ cells of P388. Mice were injected at the same site with $5\;{\times}\;10^5\;PFU$ of recombinant vaccinia virus; first, 3 days after the injection of tumor cells and thereafter once every week for 3 weeks. Intraperitoneal injections of RVVmIL-4 significantly prolonged the survival time of mice inoculated with tumor cells. All mice injected with RVVmIL-4 remained alive for 30 days after the postinoculation of tumor cells, while 100% and 70% of the animals injected with saline or wild type vaccinia virus died, respectively. In another tumor model using TS/A, tumor was established by subcutaneously inoculating $2{\times}10^5$ tumor cells to BALB/c mice. After tumor formation was confirmed on day 4 in all mice, $5\;{\times}\;10^6\;PFU$ of RVVmIL-4 was inoculated subcutaneously three times, once every week for 3 weeks. The TS/A tumor was eradicated in two of the nine mice. Seven of the nine mice treated with RVVmIL-4 developed a tumor, but tumor growth was significantly delayed compared to those treated with saline or wild type vaccinia virus. These results indicate that recombinant vaccinia viruses may be used as a convenient tool for delivering immunomodulator genes to a variety of tumors.