• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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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.

• 에너지공학
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• 제26권3호
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• pp.71-77
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• 2017

피동고압충수용 혼합형 안전주입탱크 (Hybrid SIT)의 압력평형시간은 냉각수 주입시기를 결정하는 주요인자이다. 한국원자력연구원 (KAERI)에서는 Hybrid SIT에서의 내부 열수력적 거동을 고찰하기 위해 개별효과시험 장치를 구축하였으며, 다양한 운전조건에서의 압력평형시간에 대한 민감도 시험을 수행하였다. 개별효과시험을 통해 압력평형시간을 결정하는 주요인자들을 도출하였으며, 그 중 증기의 벽면응축 및 냉각재와의 직접접촉응축이 압력평형시간을 결정하는 주요 현상임을 파악하였다. 본 연구에서는 개별효과 시험결과들을 이용하여 각각의 응축현상들이 압력평형에 미치는 영향을 정량적으로 분석하고 혼합형 SIT의 압력평형시간을 예측하기 위한 방법론을 제시하였다.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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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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• 제38권1호
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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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• 제53권10호
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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.

• 유기물자원화
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• 제16권4호
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• pp.74-81
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• 2008

현재 전국 대형생활폐기물 소각시설은 음식물류폐기물 분리배출로 인하여 반입폐기물의 가연분 함량은 증가하고 수분 함량은 감소하는 성상의 변화를 보이고 있다. 이러한 폐기물 성상의 변화는 반입폐기물의 발열량을 증가시켜 소각시설의 수명 단축 및 가동률을 저하시키는 문제를 발생시키고 있다. 따라서 본 연구는 인천광역시의 점증하는 생활폐기물에 대한 효율적인 소각시설운영방안을 제안하기 위한 연구로써 인천광역시 생활폐기물의 성상변화가 소각시설에 미치는 문제점과 음식물류폐기물 혼합소각에 의한 발열량 관리방안에 대하여 검토하였다. 그 결과 음식물류폐기물과 생활폐기물의 혼합소각은 폐기물의 발열량이 지속적으로 상승하고 있는 추세를 감안할 때 발열량의 저감 역할을 함으로써 소각시설의 적정운영과 동시에 음식물류폐기물의 처리비용을 절감 할 수 있는 경제적 효과를 기대할 수 있을 것으로 판단된다.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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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.

• 급식외식위생학회지
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• 제2권2호
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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.

• 에너지공학
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• 제25권1호
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• pp.185-191
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• 2016

피동충수용 혼합형 안전주입탱크는 한국원자력연구원에서 제안한 원자력 피동안전계통의 한 종류로, 안전주입탱크의 상부와 가압기를 연결하여 모든 운전압력 조건에서 냉각수 주입이 가능하도록 개선한 시스템이다. 본 연구에서는 피동충수용 혼합형 안전주입탱크, 가압기와 원자력압력용기에 대한 압력 네트워크를 통해 피동충수용 혼합형 안전주입탱크와 가압기의 압력이 평형이 되는 조건을 이론적으로 도출하였으며, 개별효과시험장치를 이용하여 안전주입탱크에서 발생하는 다양한 열수력 현상(증기응축 및 열혼합 현상)들을 파악하였다.

• Wind and Structures
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• 제14권6호
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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.