• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2438-2446
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• 2023

To cool down a nuclear reactor core and prevent the fuel damage without a pump-driven active component during any anticipated accident, the passive emergency core cooling system (PECCS) was designed and adopted in an advanced light water reactor, i-POWER. In this study, for a validation of the cooling capability of PECCS, thermal-hydraulic integral effect tests were performed with the ATLAS facility by simulating intermediate and small break loss-of-coolant accidents (IBLOCA and SBLOCA). The test result showed that PECCS could effectively depressurize the reactor coolant system by supplying the safety injection water from the safety injection tanks (SITs). The result pointed out that the safety injection from IRWST should have been activated earlier to inhibit the excessive core heat-up. The sequence of the PECCS injection and the major thermal hydraulic transient during the SBLOCA transient was similar to the result of the IBLOCA test with the equivalent PECCS condition. The test data can be used to evaluate the capability of thermal hydraulic safety analysis codes in predicting IBLOCA and SBLOCA transients under an operation of passive safety system.

• Journal of the Korean Society of Safety
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• v.35 no.3
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• pp.1-5
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• 2020

The leakage accident from a storage tank in an oil refinery plant occurred in April 2014 and the total loss is KRW 18 billion. This accident has prompted many companies to develop their own mitigation system to minimize the loss of the leakage accident. The aim of this study is to design the temporary storage facility system for dealing with leakage accidents. The basic concept of this system is that the leakage fluid of a hazardous material flows into a temporary storage tank and this is transferred to a spare tank by a pump as avoiding the overflow of a temporary storage tank. In order to design this system, the leakage velocity and quantity according to time series should be evaluated. In addition, a proper pump capacity should be determined to avoid repeating the pump switching on and off frequently. In this study, the benzene tank is selected to verify the efficacy of this system. This study can play a critical role to provide a guideline for designing a new system.

• Nuclear Engineering and Technology
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• v.41 no.4
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• pp.477-492
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• 2009

In this paper, we discuss the experiences during the preparation of the Wolsong Low- and Intermediate-Level Radioactive Waste Disposal Center. These experiences have importance as a first implementation for the national LILW disposal facility in the Republic of Korea. As for the progress, it relates to the area of selected disposal site, the disposal site characteristics, waste characteristics of the disposal facility, safety assessment, and licensing process. During these experiences, we also discuss the necessity for new organization and change for a radioactive waste management system. Further effort for the safe management of radioactive waste needs to be pursued.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.359-362
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• 2008

Middle domestic the occurrence size which stews recently from the Korean Peninsula circumference country is augmenting on a large scale about earthquake about safe countermeasure part from the existing Natural Countermeasure Law 2008. Refers with the Earthquake Disaster Countermeasure Law to be new standard contents establishment by law and strengthened in March. Consequently the research is propelled about electric equipment earthquake-proof plan and countermeasure. The present paper investigated an equipment by domestic facility present condition about the change disappointment electric equipment which can supply all the member in the building an investigation analysis about problem point and improvement fact. Also about overseas electric equipment investigated about earthquake-proof plan relation system and facility present condition. Investigated the electric equipment earthquake-proof plan pertinent data which is advanced from like this existing nation and the equipment and application direction must apply to domestic presented. With character presents following the guide about electric equipment earthquake-proof plan becomes feed with the fact that will be able to use.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.3892-3901
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• 2021

The pressure drop of a moisture separator in a steam generator is the important design parameter to ensure the successful performance of a nuclear power plant. The moisture separators have a wide range of operating conditions based on the arrangement of them. The prediction of the pressure drop in a moisture separator is challenging due to the complexity of the multi-dimensional two-phase vortex flow. In this study, the moisture separator test facility using the air/water two-phase flow was used to predict the pressure drop of a moisture separator in a Korean OPR-1000 reactor. The prototypical steam/water two-phase flow conditions in a steam generator were simulated as air/water two-phase flow conditions by preserving the centrifugal force and vapor quality. A series of experiments were carried out to investigate the effect of hydraulic characteristics such as the quality and liquid mass flux on the two-phase pressure drop. A new prediction model based on the scaling law was suggested and validated experimentally using the full and half scale of separators. The suggested prediction model showed good agreement with the steam/water experimental results, and it can be extended to predict the steam/water two-phase pressure drop for moisture separators.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1742-1756
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• 2023

The hydrogen behavior in a nuclear containment vessel is a significant issue when discussing the potential of hydrogen combustion during a severe accident. After the Fukushima-Daiichi accident in Japan, we have investigated in-depth the hydrogen transport mechanisms by utilizing experimental and numerical approaches. Computational fluid dynamics is a powerful tool for better understanding the transport behavior of gas mixtures, including hydrogen. This paper describes a Large-eddy simulation of gas mixing driven by a high-buoyancy flow. We focused on the interaction behavior of heat and mass transfers driven by the horizontal high-buoyant flow during density stratification. For validation, the experimental data of the Containment InteGral effects Measurement Apparatus (CIGMA) facility were used. With a high-power heater for the gas-injection line in the CIGMA facility, a high-temperature flow of approximately 390 ℃ was injected into the test vessel. By using the CIGMA facility, we can extend the experimental data to the high-temperature region. The phenomenological discussion in this paper helps understand the heat and mass transfer induced by the high-buoyancy flow in the containment vessel during a severe accident.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.4_2
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• pp.897-908
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• 2024

Evaluating the adequacy of facility safety inspection and diagnosis services performed by private enterprises is a time-consuming and administratively complex process. This study aims to analyze the determinants that could influence the rating of these safety inspection and diagnosis services using data analytics approach. Through a comparative analysis of several machine learning algorithms suitable for multi-class classification, we selected the model with the best performance (Random Forest) and identified the main determinants using the permutation importance technique. Among the variables examined, "contract value," "days of service performed" and "adherence to fair market value" were found to be strongly correlated with the rating assessments. Furthermore, we discovered that the skills and expertise of service performing personnel significantly impacted the rating. The results of this study can contribute to the enhancement of the current post-evaluation administrative processes and offer valuable insights into rating assessments by incorporating previously unexplored variables pertaining to both service providers and the services itself.

• Korean Institute of Interior Design Journal
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• v.21 no.2
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• pp.223-230
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• 2012

These days, hospitals in Korea have great interests in healthcare accreditation. The criteria of this accreditation has been established by management, but development of the management system without facility improvement has limits. Therefore this study reclassified domestic and foreign healthcare accreditation focusing on facilities and has purpose on proposing facility elements that can be adopted in hospitals. Also, the study is relevant to the study on architecture planning of hospital according to 'Patient safety' which will be suggested in the future and has significance for establishing basis of healthcare facility planning and for improving the existing facilities. The study selected facility lists from 'healthcare accreditation' and reclassified them based on departments in the hospital. Using these lists, the study divided the hospital that has obtained 'healthcare accreditation' into departments and investigated and analyzed them. On the basis of the analysis, the study suggested facility lists involved in hand washing, waste disposal, equipment washing, quarantine, goods-movement, establishing clean/polluted area, emergency exit-way, and restricted zone.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.136-144
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• 2021

Railroad Systems, which are national infrastructure industries, cause unexpected property and human damage if they fail to function while operating. Accordingly, railroad facilities supporting the railroad system are areas where high reliability and safety are required. However, it is time for systematic and scientific maintenance to be taken away from the traditional maintenance methods, as the nation's railroad facilities are now aging seriously. The purpose of this study was to secure the safety and reliability of the aging railroad communication facilities and to improve their performance. The research subjects were selected as a precision diagnosis process for railroad communication facilities, and improvement points were derived through detailed precision diagnosis process analysis. It is deemed that this study can contribute based on securing stability, improving reliability, and continuous improvement of railroad communication facilities should be conducted in the operation of the entire railroad system.

• The Journal of Sustainable Design and Educational Environment Research
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• v.16 no.1
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• pp.1-11
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• 2017

The purpose of this study is to present the number of necessary facilities for the establishment of safety education facility for students through the analysis of situation and demand of safety experience education facilities so as to effectively implement safety education based on 7 standards of school safety education. 7 standards of school safety education and experience programs of the existing safety experience center were analyzed and the experience program was extracted based on the analysis. Based on the derived program, the experience space was set up, and the existing safety experience facility was analyzed accordingly. Based on this, the number of necessary facilities was suggested by using the calculation formula derived to estimate the scale of the facility expansion. This is the result of estimating the required number of facilities based on the 2015 school age population. In the long run, it is necessary to calculate the appropriate ratio by actually comparing the unit construction costs of the facilities and the vehicles. In consideration of this, it is necessary to plan for the long-term necessary facilities and vehicles for the construction plans.