• Nuclear Engineering and Technology
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• 제56권3호
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• pp.1066-1080
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• 2024

SMART100 has a containment pressure and radioactivity suppression system (CPRSS) for passive containment cooling system (PCCS). This prevents overheating and over-pressurization of a containment through direct contact condensation in an in-containment refueling water storage tank (IRWST) and wall condensation in a CPRSS heat exchanger (CHX) in an emergency cool-down tank (ECT). The Korea Atomic Energy Research Institute (KAERI) constructed scaled-down test facilities, SISTA1 and SISTA2, for the thermal-hydraulic validation of the SMART100 CPRSS. Three separate effect tests were performed using SISTA1 to confirm the heat removal characteristics of SMART100 CPRSS. When the low mass flux steam with or without non-condensable gas is released into an IRWST, the conditions for mitigation of the chugging phenomenon were identified, and the physical variables were quantified by the 3D reconstruction method. The local behavior of the non-condensable gas was measured after condensation inside heat exchanger using a traverse system. Stratification of non-condensable gas occurred in large tank of the natural circulation loop. SISTA2 was used to simulate a small break loss-of-coolant accident (SBLCOA) transient. Since the test apparatus was a metal tank, compensations of initial heat transfer to the material and effect of heat loss during long-term operation were important for simulating cooling performance of SMART100 CPRSS. The pressure of SMART100 CPRSS was maintained below the design limit for 3 days even under sufficiently conservative conditions of an SBLOCA transient.

• 에너지공학
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• 제28권4호
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• pp.103-110
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• 2019

국내에서 개발 중인 차세대 혁신형 안전경수로인 iPOWER는 피동용융노심냉각계통의 도입을 통해 중대사고시 노심용융물을 원자로 하부에서 장기간 냉각하고 안정화시키고자 한다. 아직 피동용융노심냉각계통의 최종 설계개념이 확정되기 전이나, 원자로용기 외벽냉각을 통한 노심용융물의 노내 억류 역시 주요 중대사고 대처 전략의 하나로 검토되고 있다. 본 연구에서는 국내에서 개발된 열수력 계통해석코드인 MARS-KS를 이용하여 원자로용기와 단열체 사이에서 형성되는 2상 자연순환 유동을 모의하였다. 냉각수의 유로를 일차원으로 모델링하고, 노심용융물의 열부하에 따른 경계조건을 정의하여 자연순환 유량을 계산하였다. 또한 냉각수의 온도 및 수위, 원자로용기 하반구 주변 기포율 및 외벽에서의 열전달모드 등 주요 열수력 변수의 과도거동을 평가하였다.

• 대한치과기공학회지
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• 제23권1호
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• pp.65-73
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• 2001

The purpose of this study was to investigate the microstucture and hardness, corrosion of pure Ti alloy, which is widely used as partial denture frame work these days, depending on the cooling method, followed by casting. The first group was bench cooling at room temperature($18^{\circ}C$), the second group was slowly cooled in the furnace from $700^{\circ}C$ to room temperature, and third. rapidly cooled in $0^{\circ}C$ water. The microstructure of each specimen observed by means of photomicrograph taken by electron microscope, in add to the physical characteristics of each specimen were obtained using the rockwell Hardnest Number. the characteristics of corrosion. The results were obtained as follows: 1. From Potentiodynamic plot. we conclude furnace-cooled specimen had the best stabiltity of passive film and that air-cooled specimen showed similar characteristics. The density of electric current of quenched specimen was the highest, which formed kind of unstable passive film. 2. Specimen cooled at room temperature (air cooling) had the highest value of hardness of 81.26HRB, specimen cooled at ice-water, $0^{\circ}C$, had the value of 78.42HRB, and specimen furnace-cooled at $700^{\circ}C$ had lowest value of 77.1HRB. 3. Quenching treated micro-structure formed martensite structure by and large. In case of air cooling, we could see $\alpha$-structure widmanstatten formed overall. In furnace cooling, widmanstatten structure and various shape $\alpha$-structures forming colony with direction were detected.

• 조명전기설비학회논문지
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• 제25권1호
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• pp.101-106
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• 2011

The failure of cooling system in Superconducting Fault Current Limiter(SFCL) increases the impedance of superconducting device, and due to malfunction of inner switches the SFCL opens the distribution system inadvertently when required to do so. In this paper, the ground fault and short circuit fault were classified as active failure and the open circuit fault was passive failure. A reliability model of SFCL considers the passive failure as well as active failure, and in the case study the reliability indices of distribution system are evaluated. It is possible that the reliability evaluation excluded passive failure makes the customers reliability seem so worse than it really was. Therefore, the reliability models of SFCL must include the active failure and passive failure together to evaluate the reliability of distribution system connected SFCL.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2001년도 춘계학술발표대회 논문집
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• pp.117-120
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• 2001

This study is a preliminary research to develop design principles for environmentally friendly housing. The purposes of study are to investigate the literatures related passive design for summer and theory of ventilation, to analyze the indoor airflow patterns in traditional Korean house during summer, and to propose the design factors for effective passive cooling system. The analysis for airflow patterns was focused on the ‘An bang’and the ‘Dae Chung’in the ‘An Chae’of a traditional house located in Seoul. Field measurements of air temperature and air velocity were carried out at 30 different measuring points with 8 different window-opening conditions. The measurements were taken on the hottest summer days in August 2000. It is concluded that from an environmentally friendly standpoint design factors to control indoor thermal environment by a passive cooling system during the summer are as follows; ceiling structure has thermal performance like a time-lag effect, optimum height and length of eaves which can prevent sunlight and divert airflow toward the sitting level, building arrangement acceptable the prevailing wind, strategic window arrangement which makes cross ventilation possible (especially north-south) at the sitting level, window opening condition which is possible to intersect two cross-ventilation stream at the main living areas, northward windows remaining in shade to create the air pressure difference, and planning building shape like a bracket that has optimum width and depth.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.85-89
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• 2008

This study carried out field observations of measuring thermal environment, especially evaluating amount of water evaporation at roof Pond by field observations during the summer. Thermal environment measuring was categorized as air temperature, water temperature of roof pond, surface temperature, globe temperature, short and long wave radiation, net radiation, and amount of water evaporation by water level measurement. Results from this study could be used as fundamental for reducing heat Island phenomena.

• Nuclear Engineering and Technology
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• 제30권1호
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• pp.26-39
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• 1998

The containment pressure and temperature transient analysis computer code CONTEMPT4/MOD5 is modified to incorporate the passive containment cooling models. The correlations are selected from the existing experimental heat transfer correlations to model the natural and mixed convection in annular space between the containment shell and the shield building. The evaporative heat transfer of the water film on the outer shell of the containment is modeled using the correlations derived from the analogy between the heat and mass transfer. The modified code is applied to the Ap600 containment transient analysis for the model verification and the results are compared to the results of GOTHIC calculation done by Westinghouse. Also, d series of parametric sensitivity studies of heat transfer correlations, water film ratio and delay time of the wet cooling on the containment peak pressure and temperature following LOCA are performed for the containment of 1000MWe passive plant, KP1000.

• Corrosion Science and Technology
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• 제22권5호
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• pp.305-313
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• 2023

The objective of this study was to investigate the effectiveness of sodium dodecyl benzene sulfonate (SDBS) as a corrosion inhibitor on the pitting corrosion behavior of aluminum alloys used in electric vehicle battery cooling systems within a mixture of ethylene glycol and water (EG-W) coolant. Potentiodynamic polarization testing revealed unstable passive film formation on the aluminum alloys in the absence of SDBS. However, the addition of SDBS resulted in a robust passive film, enhancing the pitting corrosion resistance across all examined alloys. Pitting corrosion was predominantly observed near intermetallic compounds in the presence of Cl? ions, which was attributed to galvanic interactions. Among tested alloys, A1040 demonstrated superior resistance due to its lower areal fraction of precipitates and donor density. The incorporation of SDBS inhibitors mitigated the overall pitting corrosion process by hindering Cl? ion penetration. These findings suggest that SDBS can significantly improve pitting corrosion resistance in aluminum alloys employed in battery coolant environments.

• Architectural research
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• 제22권2호
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• pp.41-52
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• 2020

Laboratory buildings with specialized equipment and ventilation systems pose challenges in terms of efficient energy use and initial construction costs. Additionally, lab spaces should have flexible and efficient layouts and provide a comfortable indoor research environment. Therefore, this study aims to identify the correlation between the facade of a building and its interior layout from case studies of energy-efficient research labs and to propose passive energy design strategies for the establishment of an optimal research environment. The case studies in this paper were selected from the American Institute of Architects Committee on the Environment Top Ten Projects and Leadership in Energy and Environmental Design (LEED) certified research lab projects. In this paper, the passive design strategies of space zoning, façade design devices to control heating and cooling loads were analyzed. Additionally, the relationships between these strategies and the interior lab layouts, lab support spaces, offices, and circulation areas were examined. The following four conclusions were drawn from the analysis of various cases: 1) space zoning for grouping areas with similar energy requirements is performed to concentrate similar heating and cooling demands to simplify the HVAC loads. 2) Public areas such as corridor, atrium, or courtyard can serve as buffer zones that employ passive solar design to minimize the mechanical energy load. 3) A balanced window-to-wall ratio (WWR), exterior shading devices, and natural ventilation systems are applied according to the space programming energy requirements to minimize the dependence on mechanical service. 4) Lastly, typical laboratory space zoning categories can be revised, reversed, and even reconfigured to minimize the energy load and adjust to the site context. This study can provide deep insights into various design strategies employed for construction of green laboratories along with intuitive arrangement of various building components such as laboratory spaces, lab support spaces, office spaces, and common public areas. The key findings of this study can contribute towards creating improved designs of laboratory facilities with reduced carbon footprint and greenhouse emissions.

• 한국가스학회지
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• 제11권2호통권35호
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• pp.31-36
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• 2007

가스 냉온수기용 STS 304 배관 용접부의 부식특성을 연구하기 위하여, 0.5M $H_2SO_4+0.01M$ KSCN 수용액 중에서 전기화학적 분극시험, 금속조직시험 과 경도시험을 실시하여 STS 304배관 용접부의 양극분극거동, 인가전위에 따른 부식거동, 용접부의 금속조직 및 경도거동를 고찰하였다. 다음과 같은 결론을 얻었다. 1) 임계양극전류밀도는 모재보다 용접열영향부에서 많이 배류되고, 기본부동태전위는 모재보다 용접열영향부에서 더 높게 된다. 2) 부동태전류밀도는 모재보다 용접열영향부에서 더 많이 배류되고, 부동태영역은 용접열영향부보다 모재가 더 크게 된다. 3)인가전압에 의한 용접열영향부의 전류밀도는 모재의 전류밀도보다 더 많이 배류된다.