• 한국안전학회지
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• 제33권5호
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• pp.164-169
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• 2018

A detailed fatigue evaluation procedure was developed to mitigate the excessive conservativeness of the conventional environmental fatigue evaluation method for the pressurizer spray line elbow of domestic new nuclear power plants. The pressurizer spray line is made of austenitic stainless steel, which is relatively sensitive to the environmentally assisted fatigue, and has a low degree of design margin in terms of environmentally assisted fatigue due to the thermal stratification phenomenon on the pipe cross section as a whole or locally. In this study, to meet the environmental fatigue design requirements of the pressurizer spray line elbow, the new environmental fatigue evaluation has been performed, which used the ASME Code NB-3200-based detailed fatigue analysis and the environmental fatigue correction factor instead of the existing NB-3600 evaluation method. As a result, the design requirements for environmentally assisted fatigue were met in all parts of the pressurizer spray line elbow including the fatigue weakened zones by thermal stratification.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.33-38
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• 2009

Energy loss from windows accounts for large scores of heating and cooling loads also in energy saving apartments that is reduced over 30% of total energy consumption. Movable reflective insulations, insulation shutters, blinds, insulated shades are used to reduce energy loads from windows. In this study, energy saving performance of insulated shades was simulated by control methods. According to installation of insulated shades, heating loads were decreased about $10.5{\sim}11.3%$, and cooling loads are decreased about $11.0{\sim}15.5%$ on an energy saving apartment. The heating peak load was reduced about 9.5% by insulated shades, but the cooling peak load is hardly ever decreased. Because in the condition of cooling peak load, latent cooling loads accounts for large score of cooling loads. Difference of the energy loads by a schedule control method and an outdoor detection control was no more than 5% for a base model. In the case of insulated shades with automatic control system, simple time schedule control system would be more efficient than outdoor detection control system that should use several sensors.

• 한국산업보건학회지
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• 제22권4호
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• pp.276-283
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• 2012

Objectives: This study was conducted to survey the viewpoints on the material safety data sheets(MSDS) training for safety and health managers(SHMs) and workers. Subjects and Methods: A surveillance was made using a self-reported questionnaire for 78 SHMs and 122 workers to survey their viewpoints on the MSDS training. Survey results were analyzed using the SPSS program(Version 12.0 SPSS Inc., USA). Results: The result of the study shows that there are contrasts with the cognition of SHMs' and workers' on the education of MSDS and the program preference for education efficiency of MSDS. Workers were significantly more interested in the MSDS education than the SHMs did. Workers preferred the education program which is easily to be understood, to voluntarily participate on MSDS education, but SHMs did the quiz program. Also we found that the SHMs wanted to learn the education program via the expert(37.3%) rather than education resources(33.3%) which were served by government or relevant agency. In contrast, workers wanted the audio-visual education program, which is mainly consisted of accident cases (33.3%), rather than periodical education program(22.1%). Conclusions: This study showed that effectiveness of MSDS education was associated with the program served by company, and the education program for the voluntary participation of the workers should be made practical and attractive.

• Tribology and Lubricants
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• 제10권1호
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• pp.14-26
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• 1994

The minimum oil film thickness(MOFT) in the connecting-rod bearing of a 1.5 liter, L-4, gasoline engine is measured up to 5500 rpm and calculated to study the dynamically loaded engine bearing. Short bearing approximation and Mobility method are used for theoretical analysis of oil film characteristics. And cylinder pressure, crank-pin surface temperature and bearing temperature are measured as the input data of theoretical analysis. The MOFT are measured by the total capacitance method(TCM). To improve the reliability of the test results, a reasonable determination method of bearing clearance is introduced and used, and the effects of cavitation and aeration on the test results are neglected. The crankshaft is grounded by means of a slip ring. A scissor type linkage system was developed to measure the MOFT and bearing temperature. The effects of engine speed, load and oil viscosity on the measured and calculated minimum oil film thicknesses are investigated at 1500 to 5500 rpm. From the comparison between the measured and calculated MOFT, it is found that a qualitative similarity exists between them, but in all cases, the measured MOFT are smaller than those calculated.

• International Journal of Fluid Machinery and Systems
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• 제3권1호
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• pp.58-66
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• 2010

A steam control valve is used to control the flow from the steam generator to the steam turbine in thermal and nuclear power plants. During startup and shutdown of the plant, the steam control valve is operated under a partial flow conditions. In such conditions, the valve opening is small and the pressure deference across the valve is large. As a result, the flow downstream of the valve is composed of separated unsteady transonic jets. Such flow patterns often cause undesirable large unsteady fluid force on the valve head and downstream pipe system. In the present study, various flow patterns are investigated in order to understand the characteristics of the unsteady flow around the valve. Experiments are carried out with simplified two-dimensional valve models. Two-dimensional unsteady flow simulations are conducted in order to understand the experimental results in detail. Scale effects on the flow characteristics are also examined. Results show three types of oscillating flow pattern and three types of static flow patterns.

• Nuclear Engineering and Technology
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• 제49권3호
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• pp.632-637
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• 2017

Even though the potential for an accident in nuclear power plants is very low, multiple emergency plans are necessary because the impact of such an accident to the public is enormous. One of these emergency plans involves a robotic system for investigating accidents under conditions of high radiation and contaminated air. To develop a robot suitable for operation in a nuclear power plant, we focused on eliminating the three major obstacles that challenge robots in such conditions: the disconnection of radio communication, falling on uneven floors, and loss of localization. To solve the radio problem, a Wi-Fi extender was used in radio shadow areas. To reinforce the walking, we developed two- and four-leg convertible walking, a floor adaptive foot, a roly-poly defensive falling design, and automatic standing recovery after falling methods were developed. To allow the robot to determine its location in the containment building, a bar code landmark reading method was chosen. When a severe accident occurs, this robot will be useful for accident condition monitoring. We also anticipate the robot can serve as a workman aid in a high radiation area during normal operations.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2019년도 춘계학술대회
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• pp.29-32
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• 2019

정보통신기술의 발전으로 인하여 선박 내 시스템 간 또는 선박과 육상 시설 간의 정보 교환 및 통신이 용이하게 되어 업무 효율이 향상되고 있다. 그러나 이러한 회사와 선박의 업무 환경의 변화는 회사 및 선박의 시스템으로의 비인가된 접근 또는 악성코드 감염과 같은 사이버보안 사고 발생 가능성을 높이는 요인이 되어 안전, 환경 및 상업적으로 중대한 피해를 야기할 수 있다. 따라서 증가하는 사이버위헙을 식별하고 대응하기 위하여 사이버 리스크 기반 접근법이 필요하게 되었다. 본 논문에서는 해사 사이버보안 동향을 분석하고 해상 사이버보안 시스템 구축을 위한 가이드라인을 제공하고자 한다.

• 신재생에너지
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• 제19권2호
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• pp.13-22
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• 2023

With the increased interest in renewable energy, various hydrogen production technologies have been developed. Hydrogen production can be classified into green, blue, gray, and pink hydrogen depending on the production method; each method has different technical performance, costs, and CO₂ emission characteristics. Hence, selecting the technology priorities that meet the company strategy is essential to develop technologically and economically feasible projects and achieve the national carbon neutrality targets. In addition, in early development technologies, analyzing the technology investment priorities based on the company's strategy and establishing investment decisions such as budget and human resources allocation is important. This study proposes a method of selecting priorities for various hydrogen production technologies as a specific implementation plan to achieve the national carbon neutrality goal. In particular, we analyze key performance indicators for technology, economic feasibility, and environmental performance by various candidate technologies and suggest ways to score them. As a result of the analysis using the aforementioned method, the priority of steam methane reforming (SMR) technology combined with carbon capture & storage (CCS) was established to be high in terms of achieving the national carbon neutrality goal.

• 한국농촌건축학회논문집
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• 제24권4호
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• pp.97-106
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• 2022

During the Japanese colonial period, Japan exploited the entire Korean Peninsula and targeted not only cities but also rural areas. The exploitation of rural area was accelerated with the support of Oriental colonization Company and The countryside was a living scene of direct exploitation. However, most of the research was concentrated in representative port cities such as Kunsan, which transports logistics such as rice and grains. There was insufficient research on how Japanese entered the country, how Korean were plundered, and the rural villages that were the target of exploitation. The contents of hi-exploitation were also historical and historical humanities such as colonial land ownership and farm management, and the spatial structure of the existing traditional villages were insufficiently investigated. Hwaho-ri, Shin Taein-eup, Jeollabuk-do, centered on Yongseo Village, there are many traces of farm houses, hospitals, employee residences, schools, churches, and Oriental colonization Company This study aims to study what changes traditional rural villages have brought by the Japanese colonial rule, centering on Hwaho-ri Village.

• 벤처창업연구
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• 제10권5호
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• pp.83-92
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• 2015

최근 새로운 업무문화인 코워킹과 이러한 분위기를 조성해주는 코워킹스페이스가 1인 창조기업 및 스타트업을 지원하는 센터들을 중심으로 급격히 증가하고 있다. 하지만 아직 서울지역을 제외한 나머지 지역에서는 코워킹에 대한 지원과 코워킹스페이스를 수용은 하고 있지만 이에 대한 정확한 인식 및 관련 운영활동에 대해서는 다소 부재한 것으로 나타나고 있다. 따라서 본 연구에서는 이에 대한 탐색적 연구를 진행하기 위하여 큰 연구문제인 '코워킹에 대한 인식 및 사례와 코워킹스페이스 수용'과 작은 연구문제 '코워킹스페이스 운영활동'를 주제로 부산지역의 1인 창조기업 비즈니스센터를 중심으로 현장조사와 매니저 심층인터뷰를 실시하였다. 결과를 종합해보면 먼저 쿤 연구문제에 대한 분석결과는 코워킹에 대한 인식과 사례가 있었지만 성과를 위해 매니저가 인위적으로 진행한 것이 대부분이었고, 코워킹스페이스는 교류공간으로 중요하게 인식하고는 있었지만 사무기기가 지원되는 공용 공간 수준으로 활용되고 있었다. 작은 문제에 대한 분석결과에서는 '공간 및 인테리어', '제휴 및 파트너쉽', '커뮤니티 및 커뮤니케이션'에 대한 인식과 활동이 낮게 나타났는데 이에 대한 개선방안을 우수사례를 통해 제시하였다. 본 연구는 현장방문 및 심층인터뷰를 통해 정성적으로 이루어져 정량적인 분석에서 파악할 수 없는 의견까지 수집하고 분석하여 실제적으로 코워킹스페이스를 수용하고자 하는 이에게 시사점을 제시하고 있다는 점에서 의미가 있다.