• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.356-367
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• 2018

A series of tests dedicated to station blackout (SBO) accident scenarios have been recently performed at the $Prim{\ddot{a}}rkreislauf-Versuchsanlage$ (primary coolant loop test facility; PKL) facility in the framework of the OECD/NEA PKL-3 project. These investigations address current safety issues related to beyond design basis accident transients with significant core heat up. This work presents a detailed analysis using the best estimate thermal-hydraulic code TRACE (v5.0 Patch4) of different SBO scenarios conducted at the PKL facility; failures of high- and low-pressure safety injection systems together with steam generator (SG) feedwater supply are considered, thus calling for adequate accident management actions and timely implementation of alternative emergency cooling procedures to prevent core meltdown. The presented analysis evaluates the capability of the applied TRACE model of the PKL facility to correctly capture the sequences of events in the different SBO scenarios, namely the SBO tests H2.1, H2.2 run 1 and H2.2 run 2, including symmetric or asymmetric secondary side depressurization, primary side depressurization, accumulator (ACC) injection in the cold legs and secondary side feeding with mobile pump and/or primary side emergency core coolant injection from the fuel pool cooling pump. This study is focused specifically on the prediction of the core exit temperature, which drives the execution of the most relevant accident management actions. This work presents, in particular, the key improvements made to the TRACE model that helped to improve the code predictions, including the modeling of dynamical heat losses, the nodalization of SGs' heat exchanger tubes and the ACCs. Another relevant aspect of this work is to evaluate how well the model simulations of the three different scenarios qualitatively and quantitatively capture the trends and results exhibited by the actual experiments. For instance, how the number of SGs considered for secondary side depressurization affects the heat transfer from primary side; how the discharge capacity of the pressurizer relief valve affects the dynamics of the transient; how ACC initial pressure and nitrogen release affect the grace time between ACC injection and subsequent core heat up; and how well the alternative feeding modes of the secondary and/or primary side with mobile injection pumps affect core quenching and ensure stable long-term core cooling under controlled boiling conditions.

• Microbiology and Biotechnology Letters
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• v.47 no.3
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• pp.390-400
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• 2019

In this study, strains isolated from soil samples collected from Busan, Changwon, and Jeju Island were examined to verify their abilities of phosphate solubilization and nitrogen fixation, production of indole-3-acetic acid (IAA), siderophore, and 1-aminocylopropane-1-carboxylyic acid (ACC) deaminase in order to select strains that promote plant growth and play a role in biocontrol of pests or pathogens. According to the results of this study, most of the isolated strains were found to have ability of phosphate solubilization, nitrogen fixation, IAA production, siderophore production, and production of ACC deaminase. These isolated strains might help plant growth by directly improving absorption of nutrients essential for phosphate solubilization and nitrogen fixation. In addition, they can promote plant growth and control resistance to plant diseases through extracellular enzyme activity and antifungal activity. In addition, most of the selected strains were found to survive in various environmental conditions such as temperature, salinity, and pH. Therefore, Pseudomonas plecoglossicida ANG14, Pseudarthrobacter equi ANG28, Beijerinckia fluminensis ANG34, and Acinetobacter calcoaceticus ANG35 were finally selected through a comparative advantage analysis to suggest their potential as novel biological agents. Further studies are necessary in order to prove their efficacy as novel biological agents through formulation and optimization of effective microorganisms, their preservation period, and crop cultivation tests.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.27 no.3
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• pp.144-157
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• 2022

Noble gases, which are chemically inert and behave conservatively in marine environments, have been used as tracers of physical processes such as air-sea gas exchange, mixing of water masses, and distribution of glacial meltwater in the ocean. For precise measurements of Ne, Ar, and Kr, we developed a mass spectrometric system consisting of a quadrupole mass spectrometer (QMS), a high vacuum preparation line, an activated charcoal cryogenic trap (ACC), and a set of isotope standard gases. The high vacuum line consists of three sections: (1) a sample extraction section that extracts the dissolved gases in the sample and mixes them with the standard gases, (2) a gas preparation section that removes reactive gases using getters and separates the noble gases according to their evaporation points with the ACC, and (3) a gas analysis section that measures concentrations of each noble gas. The ACC attached to the gas preparation section markedly lowered the partial pressures of Ar and CO₂ in the QMS, which resulted in a reduced uncertainty of Ne isotope analysis. The isotope standard gases were prepared by mixing ²²Ne, ³⁶Ar, and ⁸⁶Kr. The amounts of each element in the mixed standard gases were determined by the reverse isotope dilution method with repeated measurements of the atmosphere. The analytical system achieved precisions for Ne, Ar, and Kr concentrations of 0.7%, 0.7%, and 0.4%, respectively. The accuracies confirmed by the analyses of air-equilibrated water were 0.5%, 1.0%, and 1.7% for Ne, Ar, and Kr, respectively.

• KCID journal
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• v.7 no.1
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• pp.47-56
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• 2000

A study was performed to investigate the effect of fertilizer application on concentration of nutrients in ponded and percolated waters in experimental paddy fields. Three experimental plots, i.e., reduced, standard, and excessive plots, were laid out acc

• Proceedings of the Zoological Society Korea Conference
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• 2001.10a
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• pp.227.2-227
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• 2001

No Abstract, See Full Text

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.53.4-53
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• 2002

In this paper, we implemented the FIPA-OS framework bundle and service agent bundle over the OSGi service platform in home-sewer platform. The FIPA-OS is the first open source implementation of the FIPA standards and is a component-based toolkit implemented in Java. The FIPA-OS bundle is composed of two bundles. One is the communication bundle such as RMI, IIOP, HTTP and ACC. Another is the agent loader bundle. Experiments are conducted on the service agent communication and loading by the agent loader bundle, and the proposed bundles are successfully installed, stopped, and uninstalled over the OSGi service platform.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.101-104
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• 1999

본 논문은 서비스 제어 시스템(Service Control Point : SCP), 서비스 교환 시스템(Service Switching System : SSP), 그리고 지능형 정보제공 시스템(Intelligent Peripheral : IP)을 물리적 구성 요소로 하는 차세대지능망 (Advanced Intelligent Network : AIN) 서비스중 주요 서비스인 자동콜렉트콜(Automatic Collect Call : ACC) 서비스에 대한 지능형 정보제공 시스템에서의 자원 제공시간 (점유 시간)을 분석한 것이다. 차세대 지능망 구성요소들이 연동되어 서비스되는 상황에서 지능형정보 제공시스템에서의 서비스 시나리오를 제시하였으며, 특수 자원에 대한 자원 제공 점유 시간을 분석하였다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.27-33
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• 1999

In order to regulate cutting force at a desired level during NC lathe process, a feedrate override Adaptive Control Constraint system was developed. Nonlinear model of the cutting process was linearized as an adaptive model with a time varing process parameter. Performance of the ACC system was confirmed on the NC lathe equipped with the developed NC system through a large amount of experiment.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.452-457
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• 1998

This paper deal with problems of leakage current, shaft voltage, bearing current, and EMI, in valiable-speed AC drives. The originating mechanism is illustrated with a high-frequency equivalent circuit. Reduction methods are classified in to six categories based on the equivalent circuit. Some experimental results show that a common-mode transformer (CMT) and a common-noise canceler (ACC) can solve the problems, which have been proposed the authors.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.171-174
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• 2002

When boron ions are doped into the poly-Si films, the hydrogen ions doped with boron ions compensate the defect sites and suppress to produce damage density. These samples can be easily activated by hydrogen doping at high acceleration voltage($V_{acc}$).