• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2053-2058
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• 2004

The pressurized light water cooled, medium power (330 MWt) SMART (System-integrated Modular Advanced ReacTor) has been under development at KAERI for a dual purpose : seawater desalination and electricity generation. The SMART design verification phase was followed to conduct various separate effects tests and comprehensive integral effect tests. The high temperature / high pressure thermal-hydraulic test facility, VISTA(Experimental Verification by Integral Simulation of Transient and Accidents) has been constructed to simulate the SMART-P (the one fifth scaled pilot plant) by KAERI. Experimental tests have been performed to investigate the thermal-hydraulic dynamic characteristics of the primary and the secondary systems. Heat transfer characteristics and natural circulation performance of the PRHRS (Passive Residual Heat Removal System) of SMART-P were also investigated using the VISTA facility. The coolant flows steadily in the natural circulation loop which is composed of the steam generator (SG) primary side, the secondary system, and the PRHRS. The heat transfers through the PRHRS heat exchanger and ECT are sufficient enough to enable the natural circulation of the coolant.

• Journal of Energy Engineering
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• v.26 no.3
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• pp.71-77
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• 2017

In the event of loss of coolant accident (LOCA) and station black out (SBO) in the primary system of a nuclear reactor, the coolant water should be injected to reactor coolant system (RCS) without any intervention of operators or active components. To satisfy the requirements, hybrid safety injection tank (Hybrid SIT) was suggested by Korea Atomic Energy Research Institute (KAERI). The pressure equalizing time of Hybrid SIT is an important parameter to determine the timing of coolant injection. To predict the pressure equalizing time of the Hybrid SIT, a separate effect test facility was constructed and sensitivity tests were conducted in various conditions. The main parameter determining the pressure equalizing time was obtained from separate effect test (SET) results. The wall of condensation on the inner wall of SIT and direct contact condensation on the water surface affected to the pressure equalizing time very much. In this study, the effect of each condensation phenomena on pressure equalizing time was quantitatively analyzed from results of SET and a prediction method of pressure equalizing time was proposed.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.704-705
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• 2015

Recent research has been ongoing for modular buildings in the country, and interest increases. However, in accordance with legal restrictions in the country with regard to Project Delivery system of Modular Building, the activation of modular buildings industry is obstructed. In Korea, in accordance with national contract law, the construction contract is apply to the project delivery system of modular buildings, and in accordance with Framework Act on the Construction Industry, The project delivery system of modular buildings has to be a separate order. The definition of separate order in contract as defined in the law is that the electric work and Communication work and digestion facility work has to be separate each contract in order to be ensured professionalism. In accordance with law, the project delivery system of modular buildings is that the contract for construction is concluded with the Owner and the Construction Contractor and the contract for goods is concluded with the construction Contractor and modular manufacturer. Due to these project delivery system, the domestic factory production rate when making a modular unit is significantly reduced compared to the rate of factory production abroad and the domestic factory production rate is estimated to 10-20%. Due to the factory production rate is also low, despite what can be done at the factory the workload in construction field increases. According to the workload in field increases, the effect of the schedule reduction can be reduced. It resolved to form a consortium with a modular manufacturer and construction companies or the contract is concluded with Owner, modular manufacturer and construction companies in each. In this paper, we propose a specific project delivery system for modular building to solve the problem of the low factory production rate and the problem of schedule reduction. Through this paper, due to the variety of project delivery system on modular buildings is expected to contribute to the activation of modular buildings.

• Nuclear Engineering and Technology
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• v.38 no.1
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• pp.99-108
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• 2006

SNU-RCCS is a water pool type RCCS (Reactor Cavity Cooling System) developed for VHTR (Very High Temperature Reactor) application by SNU (Seoul National University). Since radiation heat transfer is the major process of passive heat removal in a RCCS, it is important to determine the precise emissivity of the reactor vessel. Review studies have used a constant emissivity in the passive heat removal analysis, even though the emissivity depends on many factors such as temperature, surface roughness, oxidation level, wavelength, direction, atmosphere conditions, etc. Therefore, information on the emissivity of a given material in a real RCCS is essential in order to properly analyze the radiation heat transfer in a VHTR. The objectives of this study are to develop a method for compensation of the factors affecting the emissivity measurement using an infrared thermometer and to estimate the true emissivity from the measured emissivity via the developed method, especially in the SNU-RCCS environment. From this viewpoint, we investigated factors such as the attenuation effect of the window, filling gas, and the effect of background radiation on the emissivity measurements. The emissivity of the vessel surface of the SNU-RCCS facility was then measured using a sight tube. The background radiation was subsequently removed from the measured emissivity by solving a simultaneous equation. Finally, the calculated emissivity was compared with the measured emissivity in a separate emissivity measurement device, yielding good agreement with the emissivity increase with vessel temperature in a range of 0.82 to 0.88.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3196-3206
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• 2021

For the Korean design of the PCCS (passive containment cooling system) in an innovative PWR, the overall thermal resistance around a condenser tube is dominated by the heat transfer coefficient of steam condensation on the exterior surface. It has been reported, however, that the calculated heat transfer coefficients by thermal-hydraulic system codes were much lower than measured data in separate effect tests. In this study, a new empirical model of steam condensation in the presence of a noncondensable gas was implemented into the MARS-KS 1.4 code to replace the conventional Colburn-Hougen model. The selected correlation had been developed from condensation test data obtained at the JERICHO (JNU Experimental Rig for Investigation of Condensation Heat transfer On tube) facility, and considered the effect of the Grashof number for naturally circulating gas mixture and the curvature of the condenser tube. The modified MARS-KS code was applied to simulate the transient response of the containment equipped with the PCCS to the large-break loss-of-coolant accident. The heat removal performances of the PCCS and corresponding evolution of the containment pressure were compared to those calculated via the original model. Various thermal-hydraulic parameters associated with the natural circulation operation through the heat transport circuit were also investigated.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.4
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• pp.74-81
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• 2008

Due to separate discharge of food waste, large incinerating facilities for municipal waste show the phase change that combustible contents have been increasing while the concentrations of water have been decreasing when wastes are brought in. This phase change of wastes leads to the increase of exothermic value when wastes are carried in, which causes the problems to make the durability of incinerating facilities weak and lower the capacities of them. In accordance with these problems, this study was carried out to present effective plans to operate incinerating facilities as the quantities of municipal wastes of Incheon have been gradually increasing. We examined the problems caused by the phase change of municipal waste in Incheon and managing plans to control the amounts of heat output when intermixed incineration of food waste is conducted. It is concluded that we could carry out the optimized operation of incinerating facilities as well as produce economic effect to reduce processing costs when we conduct the intermixed incineration of food waste and municipal waste, in the trend that the amounts of heat output generated by wastes are gradually increasing. This is because this operation of intermixing incineration contributes to reducing the amount of exothermic heat.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.683-693
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• 2021

Shipping has become an important sector in supporting social, economic, government, defense, security, cultural and other sectors to unite separate islands and broad seas. Thus, ports automatically become an important facility in Indonesia. The purpose of this research is to test and explain the effect of Organizational readiness for change, Service Innovation, and Corporate Image on Perceived opportunity and challenge. The research model with inferential analysis uses Structural Equation Modeling (SEM) analysis with the WarpPLS approach, expected to answer the statements of problem and be able to test the desired hypothesis. The model development in this research was based on the background, statements of problem, conceptual framework and research hypotheses. The model referred to is "Complete and Comprehensive Port." Its development was carried out through studying and synthesizing various sources. The most important source is the results of literature review in the form of theoretical developments and research results, then continued with compilation. The use of Organizational Change Readiness, Service Innovation, and Corporate Image in improving Port Competitiveness is seen as one of the novelties of this research, specifically the use of the Organizational Change Readiness variable which is often used in high-flexibility companies but now used in port companies as well.

• Journal of the FoodService Safety
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• v.2 no.2
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• pp.97-102
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• 2021

The purpose of this study was to investigate the effect of developing and continuously providing on-line hygiene education programs on the improvement of hygiene conditions in children's cafeterias. As a result of the 2020 sanitation and safety checklist analysis, 6 items (personal hygiene, separate use, clean ventilation, temperature control of refrigerators, country of origin, food distribution) were derived and on-line hygiene education programs for each of 6 items were produced. ① Customized educational materials and self-inspection checklists were provided to 208 children's cafeterias. After that, educational videos were provided through Kakao Talk twice a week for 6 months, and they were made available for viewing at any time through YouTube upload, ③ Kakao Talk Through this, a quiz related to the educational video was conducted to give feedback for interaction with the cook. As a result of analyzing the total hygiene and safety checklist score of all registered facility catering centers by visit order, in 2020 it was 82.8 points/100 points, but in 2021, it was 84.2 points (1st round), 89.3 points (2nd round), 91.4 points (3 points) The score improved significantly (p<0.001) as the on-line hygiene education program continued. As a result, significant (p<0.001) changes were observed in the items of 'Knife, chopping board' and 'Sanitation clothes, sanitary hat, sanitary shoes, apron, and sanitary gloves', confirming a clear improvement effect. Therefore, it is considered that the on-line hygiene education program will play a positive role in showing a lasting effect on improving hygiene management in children's cafeterias.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.185-191
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• 2016

The Hybrid Safety Injection Tank is a passive safety injection system that enables the safety injection water to be injected into the reactor pressure vessel throughout all operating pressures by connecting the top of the SIT and the pressurizer(PZR). In this study, the condition for balancing the pressure between the Hybrid SIT and PZR was derived theoretically. The pressure balancing condition was set at the point where the velocity of the Hybrid SIT coolant injected into the Direct Vessel Injection(DVI) line was at or above zero. If the condition was derived from a pressure network for the Hybrid SIT, pressurizer, and reactor pressure vessel, the pressure difference between the pressurizer and SIT is less than 0.07 MPa.

• Wind and Structures
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• v.14 no.6
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• pp.517-536
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• 2011

The assessment of wind-induced motion plays an important role in the development and design of the majority of today's structures that push the limits of engineering knowledge. A vital part of the design is the prediction of wind-induced tall building motion and the assessment of its effects on occupant comfort. Little of the research that has led to the development of the various international standards for occupant comfort criteria have considered the effects of the low-frequency motion on task performance and interference with building occupants' daily activities. It has only recently become more widely recognized that it is no longer reasonable to assume that the level of motion that a tall building undergoes in a windstorm will fall below an occupants' level of perception and little is known about how this motion perception could also impact on task performance. Experimental research was conducted to evaluate the performance of individuals engaged in a manual tracking task while subjected to low level vibration in the frequency range of 0.125 Hz-0.50 Hz. The investigations were carried out under narrow-band random vibration with accelerations ranging from 2 milli-g to 30 milli-g (where 1 milli-g = 0.0098 $m/s^2$) and included a control condition. The frequencies and accelerations simulated are representative of the level of motion expected to occur in a tall building (heights in the range of 100 m -350 m) once every few months to once every few years. Performance of the test subjects with and without vibration was determined for 15 separate test conditions and evaluated in terms of time taken to complete a task and accuracy per trial. Overall, the performance under the vibration conditions did not vary significantly from that of the control condition, nor was there a statistically significant degradation or improvement trend in performance ability as a function of increasing frequency or acceleration.