• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.18 no.2
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• pp.69-76
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• 2022

In order to prepare for a future nuclear market, research for developing floating small modular reactor has been initiated with the aim of differentiating it from large nuclear power plants such as distributed power, heat supply to remote communities and sea water desalination. Depending on the characteristics of the small modular reactor, it is necessary to design a plate and shell heat exchanger that can be manufactured smaller than the U-tube recirculation method. In this study, 12 cases are selected by changing the diameter of the heat plate, the thickness of the device body and the size of the stiffener. Finite element analysis is performed by setting the stress classification lines for the point at which deformation is expected under external pressure conditions for these analysis cases. For the basic design of the plate and shell heat exchanger, the optimal conditions are derived by analyzing the tendency of stress change in the device body and stiffener.

• Nuclear Engineering and Technology
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• v.50 no.4
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• pp.562-569
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• 2018

Recently, human errors have very rarely occurred during power generation at nuclear power plants. For this reason, many countries are conducting research on smart support systems of nuclear power plants. Smart support systems can help with operator decisions in severe accident occurrences. In this study, a smart support system was developed by integrating accident prediction functions from previous research and enhancing their prediction capability. Through this system, operators can predict accident scenarios, accident locations, and accident information in advance. In addition, it is possible to decide on the integrity of instruments and predict the life of instruments. The data were obtained using Modular Accident Analysis Program code to simulate severe accident scenarios for the Optimized Power Reactor 1000. The prediction of the accident scenario, accident location, and accident information was conducted using artificial intelligence methods.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.3-9
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• 2008

Recently, the plant industries are being activated and plant control systems use various technologies. Because the optimized design for the plants is very important for the reducing of operation and maintenance costs, automatic control systems become more important. Plant control systems consist of the master controller, the plant networks, the programming environment for engineering, monitoring software and the field devices. The control systems should have reliability, availability and safety. Modular architecture of hardware and software makes flexible configuration of the control systems. Each component should have diagnostic functions. It follows industrial standards and makes open systems. Open systems increase accessibility against the data which is distributed in the plants. The controllers including processor and communication modules use the up-to-date technology. They have real time and fault tolerant function by duplicating processors or networks. It also enables to make the distributed control systems. The distributed architecture makes more scalable main control system. Automatic control systems can be operated with better performance. In this paper, we analyzed the requirements of the seawater desalination plants and made some consideration facts for developing the optimized controller. Also we described the design concept of the main controller, which consists of several modules. We should validate and complement the design for the reliability and better performance.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2379-2381
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• 2002

국내 증기터빈 발전소의 기계식 터빈제어시스템을 국내 기술에 의해 디지털 삼중화 제어시스템으로 개조하여 현재 성공적으로 운전되고 있다. 적용된 시스템의 구성 및 기능에 대해서 설명하고, 간략한 시운전 결과에 대해서 언급하고자 한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.3-4
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• 2007

Many electrochemical power devices such as solid state batteries and solid oxide fuel cell have been studied and developed for solving energy and environmental problems. Fuel cell is a modular, high efficient and environmentally energy conversion device, it has become a promising option to replace the conventional fossil fuel based electric power plants. This paper offers some new perspectives on fuel cell development and commercialization which come from the broad consideration of the commercialization efforts of the entire fuel cell industry.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2743-2759
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• 2020

A detailed computational fluid dynamics (CFD) simulation analysis model was developed using ANSYS CFX 16.1 and analyzed to simulate the basic design and internal flow characteristics of a 180 MW small modular reactor (SMR) with a natural circulation flow system. To analyze the natural circulation phenomena without a pump for the initial flow generation inside the reactor, the flow characteristics were evaluated for each output assuming various initial powers relative to the critical condition. The eddy phenomenon and the flow imbalance phenomenon at each output were confirmed, and a flow leveling structure under the core was proposed for an optimization of the internal natural circulation flow. In the steady-state analysis, the temperature distribution and heat transfer speed at each position considering an increase in the output power of the core were calculated, and the conceptual design of the SMR had a sufficient thermal margin (31.4 K). A transient model with the output ranging from 0% to 100% was analyzed, and the obtained values were close to the T_hot and T_cold temperature difference value estimated in the conceptual design of the SMR. The K-factor was calculated from the flow analysis data of the CFX model and applied to an analysis model in RELAP5/MOD3.3, the optimal analysis system code for nuclear power plants. The CFX analysis results and RELAP analysis results were evaluated in terms of the internal flow characteristics per core output. The two codes, which model the same nuclear power plant, have different flow analysis schemes but can be used complementarily. In particular, it will be useful to carry out detailed studies of the timing of the steam generator intervention when an SMR is activated. The thermal and hydraulic characteristics of the models that applied porous media to the core & steam generators and the models that embodied the entire detail shape were compared and analyzed. Although there were differences in the ability to analyze detailed flow characteristics at some low powers, it was confirmed that there was no significant difference in the thermal hydraulic characteristics' analysis of the SMR system's conceptual design.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.4
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• pp.23-31
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• 2005

Green spaces in cities were insufficient and decreased as artificial structures increase. Accordingly, greening rooftop space contributed to urban ecosystems as green space. Especially, since 2002 Seoul supported rooftop greening and introduced 'Ecology-area rates'. Thus rooftop greening had the potentiality of extension. This prepared the extensive rooftop greenings within planting-base for extensive management rooftop greening system to be easily popularized. The extensive rooftop greening conducted from 1997-2005 reported that soil depth was 8cm and soil mixtures were 5 types. And plant were Crysanthemum zawaskii var. latilobum, Aster hayatae, Crysanthemum zawaskii herb. ssp. coreanum, Sedum sarmentosum, Sedum rotundifolium, Sedum oryzifolium, Sedum takemensis, Sedum middendorffianum, Sedum telerium var. purpureum, Sedum spectabile, Carypteris incana, Dianthus superbus, Hosta minor. As a result, for nine years after the modular type rooftop greening established, survival plants were Sedum takemensis, Sedum sarmentosum, Sedum spectabile, Sedum middendorffianum, Carypteris incana, Crysanthemum zawaskii var. latilobum, Sedum telerium var. purpureum, Sedum rotundifolium, Dianthus superbus. Also effect of greening was possibled soil depth 8cm. And growth of plants from 1997 to 2005 were fine on two soil mixtures of 'perlite+peatmoss+vermicompost+moisturizer' and 'perlite+moisturizer+bark(mulching)'. Invasive plants are Ixeris dentata Nakai, Ixeris chinensis var. strigosa, Youngia sonchifolia, Eragrostis ferruginea, Aster pilosus Willd., Ixeris japonica Nakai, Valpia myuros, and Setaria viridis. In conclusion, selection of suitable native plants was possible extensive management rooftop greening with effect of continuous greening. The extensive rooftop greening were lightweight and simple preparation without management and can popularize readily.

• Proceedings of the Korean Society for Quality Management Conference
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• 2004.04a
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• pp.114-119
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• 2004

Software verification and validation(V&V) is a means to develop high-quality software and assure safety and reliability for software. Also, we can achieve the desired software quality through systematic V&V activities. The software to be applied safety critical system like nuclear power plants is required to setup the V&V methodology that comply with licensing requirements for nuclear power plants and should be performed V&V activities according to it. In this paper, we classified safety-critical, safety-related and non-safety for software according to safety function to be peformed and define V&V activities to be applied software grade. Also, we defined V&V activities, procedures and documentation for each phase of software development life cycle and showed techniques and management to perform V&V. Finally, we propose the V&V framework to be applied software development of SMART(System-integrated Modular Advanced ReacTor) MMIS (Man-Machine Interface System) and to comply with domestic licensing requirements.

• Nuclear Engineering and Technology
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• v.39 no.1
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• pp.1-8
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• 2007

Hydrogen and electricity are expected to dominate the world energy system in the long term. The world currently consumes about 50 million metric tons of hydrogen per year, with the bulk of it being consumed by the chemical and refining industries. The demand for hydrogen is expected to increase, especially if the U.S. and other countries shift their energy usage towards a hydrogen economy, with hydrogen consumed as an energy commodity by the transportation, residential and commercial sectors. However, there is strong motivation to not use fossil fuels in the future as a feedstock for hydrogen production, because the greenhouse gas carbon dioxide is a byproduct and fossil fuel prices are expected to increase significantly. An advanced reactor technology receiving considerable international interest for both electricity and hydrogen production, is the modular helium reactor (MHR), which is a passively safe concept that has evolved from earlier high-temperature gas-cooled reactor (HTGR) designs. For hydrogen production, this concept is referred to as the H2-MHR. Two different hydrogen production technologies are being investigated for the H2-MHR; an advanced sulfur-iodine (SI) thermochemical water splitting process and high-temperature electrolysis (HTE). This paper describes pre-conceptual design descriptions and economic evaluations of full-scale, nth-of-a-kind SI-Based and HTE-Based H2-MHR plants. Hydrogen production costs for both types of plants are estimated to be approximately $2 per kilogram.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.5-8
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• 2004

컴퓨터기반 운전지원시스템은 운전원의 발전소 상태감시와 진단기능을 수행을 지원하여 운전원의 안전성을 향상시키는 시스템으로 80년대 중반부터 개발되어왔고, 또한 최근의 컴퓨터 기술과 도구의 빠른 발전으로 컴퓨터기반 운전지원 시스템의 개발 및 원전 적용에 대한 연구가 이루어지고 있다. 본 논문에서는 컴퓨터기반 운전원 조언 시스템의 기술 현황을 분석하고, 현재 설계를 진행중인 일체형원자로(SMART, System-integrated Modular Advanced ReacTor)에 컴퓨터기반 운전지원 시스템 적용을 위한 개발방안을 제안한다.