• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.498-503
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• 2000

A safety-related equipment for use in Nuclear Power Plant should be needed an Equipment Qualification. This paper presents the approach, methods, philosophies, and procedures for qualifying the large squirrel-cage induction electric pump motors for use in ULCHIN 5&6 Nuclear Power Plants. In this paper, the method of qualification is a combination of type test and analysis method, which is composed of Radiation exposure test, Seismic simulation test, Thermal aging analysis for non-metallic materials and Seismic analysis. It is found that the motor performs its safety function with no failure mechanism under postulated service conditions.

• 한국정밀공학회지
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• 제24권6호
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• pp.72-77
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• 2007

A safety-related equipment for the nuclear power plant should be needed an equipment qualification. In this paper, the approach, methods, philosophies, and procedures for qualifying the large squirrel-cage induction electric pump motors for use in ULCHIN 5, 6 Nuclear Power Plants were presented. The method of qualification is a combination of experimental test and analytic method, which is composed of radiation exposure test, seismic simulation test, thermal aging analysis for non-metallic materials, and seismic analysis. The results showed that the motor performed its safety function with no failure mechanism under postulated service conditions.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4317-4328
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• 2023

To ensure the measuring accuracy of the wall temperature, the outer wall temperature measurement values by using three kinds of thermocouple welding methods were analyzed and evaluated in the paper, including single-point flush-mounted in the wall groove method, single-point insert-mounted in the wall groove, and outer surface direct welding method, based on the application of a tube-in-tube condensing heat exchanger. And the impacts of silver, tin, and thermal resistance adhesive as filling materials on wall temperature measurement were also investigated, and the results were compared to that obtained without filling materials. The results showed that the wall temperatures measured by the three welding methods were lower than the theoretically calculated value. And the wall temperature measured by the outer surface direct welding method was lowest under the same experimental conditions. The wall temperatures measured by single-point flush-mounted and insert-mounted in the wall groove methods were also affected by different welding filling materials. It was found that the greater the thermal resistance of filling materials, the smaller the heat loss. By analyzing the reasons for the low measured value of wall temperature, a new wall temperature measurement method was developed to improve the accuracy of the current measurement method. Meanwhile, the outer wall temperature measurement experiments of vertical and horizontal heat transfer tubes were carried out to validate and calibrate the improved outer wall temperature measurement method. The results showed that the average outer wall temperature deviation measured by the improved wall temperature measurement method ranged from - 0.82% to +2.29% for vertical tubes and - 4.75% to - 1.44% for horizontal tubes, and the improved measurement method had good measurement accuracy.

• 한국해양공학회지
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• 제33권5호
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• pp.486-494
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• 2019

Recently, the interest in marine leisure activities has been growing rapidly with the work-life balance trend. In response to this demand, the Korean government is supporting fostering and revitalizing the relevant industries and facilities. In particular, a marina has been making efforts to change itself into a resort with multiple amenities instead of a simple mooring facility. However, the facilities in a marina for the transport of marine leisure equipment mostly consist of cranes and boat-lifts using ropes, which can result in incidents such as damage and accidents during lifting or movement. This paper proposes the equipment and support system for the safe transportation of marine leisure ships. Aluminum transport equipment was designed by performing a structural analysis to achieve a lighter weight than the existing steel products. In addition, a safety support system with alarms for tilting or obstacles and a slope monitoring system was developed to enhance the safety during operation and transportation. The safety support system developed in this study was implemented and installed in the transport system, and verified through commissioning on land.

• 산업경영시스템학회지
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• 제44권3호
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• pp.10-21
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• 2021

Recently, the demand for atypical structures with functions and sculptural beauty is increasing in the construction industry. Existing mold-based structure production methods have many advantages, but building complex atypical structures represents limitations due to the cost and technical characteristics. Production methods using molding are suitable for mass production systems, but production cost, construction period, construction cost, and environmental pollution can occur in small quantity batch production. The recent trend in the construction industry calls for new construction methods of customized small quantity batch production methods that can produce various types of sophisticated structures. In addition to the economic effects of developing related technologies of 3D Concrete Printers (3DCP), it can enhance national image through the image of future technology, the international status of the construction civil engineering industry, self-reliance, and technology export. Until now, 3DCP technology has been carried out in producing and utilizing residential houses, structures, etc., on land or manufacturing on land and installing them underwater. The final purpose of this research project is to produce marine structures by directly printing various marine structures underwater with 3DCP equipment. Compared to current underwater structure construction techniques, constructing structures directly underwater using 3DCP equipment has the following advantages: 1) cost reduction effects: 2) reduction of construct time, 3) ease of manufacturing amorphous underwater structures, 4) disaster prevention effects. The core element technology of the 3DCP equipment is to extrude the transferred composite materials at a constant quantitative speed and control the printing flow of the materials smoothly while printing the output. In this study, the extruding module of the 3DCP equipment operates underwater while developing an extruding module that can control the printing flow of the material while extruding it at a constant quantitative speed and minimizing the external force that can occur during underwater printing. The research on the development of 3DCP equipment for printing concrete structures underwater and the preliminary experiment of printing concrete structures using high viscosity low-flow concrete composite materials is explained.

• 대한기계학회논문집A
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• 제37권9호
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• pp.1183-1188
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• 2013

발전소에서 발생하는 고장은 인명 및 재정적 손실에 대한 파급효과는 매우 크므로 발전소에 사용되는 유압기기의 신뢰성은 특히 중요하다. 본 연구에서는 발전소용 유압밸브의 스풀과 슬리브 재질을 사용하여 시편을 제작, 열처리한 후 인산에스테르계열 유압작동유 침전상태에서 다양한 조건에서 실험한다. 시편의 마모량에 영향을 주는 인자들의 유의성을 평가하기 위해 $2^3$ 완전 요인 실험계획법을 적용하였으며, 고려된 인자들은 하중, 속도, 온도이다. 실험결과로부터 마모량에 대한 주효과 및 2 인자 교호작용에 대한 유의성 평가를 실시한 후 마모량과 인자들간의 수학적 모형을 도출하고자 한다.

• 한국기계연구소 소보
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• 제4권2호
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• pp.119-128
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• 1982

• 문화기술의 융합
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• 제6권1호
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• pp.477-483
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• 2020

콘크리트 박스 구조물이 열화되어 보수보강이 필요할 경우 스프레이 장비로 구조물 단면에 보수재를 분사하여 부착시키는 방법에 의존하고 있는데 천장 또는 벽체부위의 경우 시공 후 보수재 자중 또는 중력에 의해 부착력이 저하될 수 있으며 지하철 구조물의 경우 진동 등에 의해 초기 부착력이 떨어지는 문제점이 발생한다. 또한 작업자의 숙련도와 시공환경에 따라 보수품질이 변동되기에 이에 대한 보완책이 필요한 실정이다. 본 연구에서는 중력에 의한 보수재의 부착력 저하 및 인력시공에 의한 보수품질의 변동과 같은 문제점을 해결하고자 보수재 시공 후 소정의 압력을 가할 수 있는 기계식 가압장비를 개발하였다. 그리고 가압장비의 성능을 알아보고자 현장조건을 모사할 수 있는 챔버를 제작하여 가압 유무, 단면부위 및 환경조건을 달리한 부착강도를 측정한 결과 가압할 경우 그렇지 않은 경우보다 부위별로 차이가 있었으나 최대 70% 부착강도가 증가하는 효과를 얻을 수 있었다.

• 한국재료학회지
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• 제34권6호
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• pp.303-308
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• 2024

The semiconductor and display industries require the development of plasma resistant materials for use in high density plasma etching process equipment. Yttria (Y₂O₃) is a ceramic material mainly used to ensure good plasma resistance properties, which requires a dense microstructure. In commercial production, a sintering process is applied to reduce the sintering temperature of Y₂O₃. In this study, the effect of the addition of glass frit to the sintered specimen was examined when manufacturing yttria sintered specimens for semiconductor process equipment parts. The Y₂O₃ specimen was shaped into a Ø50 mm size and then sintered at 1,600 ℃ for 1~8 h. The characteristics, X-ray diffraction pattern, densities, contraction rate of the specimen, and swelling of the surface of the Y₂O₃ specimens were investigated as a function of the sintering time and glass frit addition. The Y₂O₃ specimen exhibited a density of over 4.9 g/cm³ as the sintering time increased, and the swelling phenomenon characteristics were improved by glass frit, by controlling particle size.

• Advances in nano research
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• 제16권4호
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• pp.353-363
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• 2024

The incorporation of nanoplatelets in composite and polymeric materials represents a recent and innovative approach, holding substantial promise for diverse property enhancements. This study focuses on the application of nanocomposites in the production of sports equipment, particularly soccer balls, aiming to bridge the gap between theoretical advancements and practical implications. Addressing the longstanding challenge of suboptimal interaction between carbon nanofillers and epoxy resin in epoxy composites, this research pioneers inventive solutions. Furthermore, the investigation extends into unexplored territory, examining the integration of glass fiber/epoxy composites with nanoparticles. The incorporation of nanomaterials, specifically expanded graphite and graphene, at a concentration of 25.0% by weight in both the epoxy structure and the composite with glass fibers demonstrates a marked increase in impact resistance compared to their nanomaterial-free counterparts. The research transcends laboratory experiments to explore the practical applications of nanocomposites in the design and production of sports equipment, with a particular emphasis on soccer balls. Analytical techniques such as infrared spectroscopy and scanning electron microscopy are employed to scrutinize the surface chemical structure and morphology of the epoxy nanocomposites. Additionally, an in-depth examination of the thermal, mechanical, viscoelastic, and conductive properties of these materials is conducted. Noteworthy findings include the efficacy of surface modification of carbon nanotubes in preventing accumulation and enhancing their distribution within the epoxy matrix. This optimization results in improved interfacial interactions, heightened thermal stability, superior mechanical properties, and enhanced electrical conductivity in the nanocomposite.