• 터널과지하공간
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• 제17권6호
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• pp.475-483
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• 2007

에너지원으로서 LNG 수요뿐 아니라 온실가스인 이산화탄소의 처분에 대한 필요성이 점차 증가되고 있어, 이를 위한 많은 저장시설이 요구된다. 이러한 저장시설은 안전성과 국토의 효율적 이용 등으로 인하여 지하화하는 경향이 있다. 이와 같은 온도특성을 고려해야하는 물질에 대한 지하저장시설의 건설에 있어서, 암석의 열물성은 열역학적 특성과 함께 저장시설의 설계 및 유지관리를 위한 중요한 요소이다. 본 연구에서는 암석입자의 크기와 실험온도범위를 고려하여 스트레인 게이지를 이용하여 암석의 열팽창계수를 실험적으로 측정하였다. 실험결과 열팽창계수는 온도가 내려감에 따라 감소하였으며, 국내 대표암석인 화강암에 대한 선열팽창계수의 온도관계식을 제안할 수 있었다. 본 연구에서 수행된 온도변화에 따른 시험결과는 지하저장소의 열역학적 안정성 해석과 열전파 특성을 규명하기 위한 해석에 주요 자료로 활용될 수 있을 것이다.

• 방사성폐기물학회지
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• 제3권3호
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• pp.249-256
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• 2005

우라늄 변환시설의 라군 슬러지에 함유된 질산염의 안정적 처리를 위해 물 첨가 용해를 실시한 뒤, 여과 케이크의 안정화 특성에 대하여 알아보았다. 물 용해에 의해 대부분의 질산염은 고농도 질산염 용액으로 제거되었으므로, 여과 케이크의 열분해는 $900^{\circ}C$에서 하나의 단계로 수행하였다. Muffle furnace를 이용하여 $900^{\circ}C$에서 5시간동안 여과 케이크의 열분해를 실시한 결과 라군 1 슬러지에 포함된 U은 $NaNO_3$의 열분해와 함께 $Na_{2}O{\cdot}2UO_3$의 형태로 안정화 되었다. 라군 2 열분해 잔류물의 경우에는 열분해 시 생성된 CaO가 냉각과정에서 수분과 반응하여 $Ca(OH)_2$로 전환되는 것을 TG/DTA 분석과 XRD 분석을 통해 확인할 수 있었지만, 처분장에서 대기중 노출이나 지하수의 침출 등에는 안정한 화합물로 알려져 있으므로, 특별한 첨가제의 첨가 없이 단순 열분해 후 처분이 가능할 것으로 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.120-122
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• 2004

This paper analyse impacts of Community Energy System (CES) on the grid during transition periods for integrating of the CES and the grid. In the near future, CES might be one of major energy supply structures. The basic concept of CES is that it supplies electrical and thermal energy to the local customer loads through the islanded power network separated from the grid. Therefore, the interconnection with the grid occurs only when the energy supply from the CES generators does not meet the demand of the local load. For avoiding impacting the grid during the transition operation modes of CES, it is necessary to thoroughly analyse the influences on the grid during those periods. In order to show them, in this paper, we model the CES with 2.34 WVA DG and simulate the impacts on the grid due to interconnection of CES The simulation results show that, in order to reduce bad influences of CES on the grid, CES need the efficient load management and generation control schemes during the transition periods.

• Carbon letters
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• 제4권1호
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• pp.36-39
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• 2003

Carbon and carbon-based materials are used in nuclear reactors and there has recently been growing interest to develop graphite and carbon based materials for high temperature nuclear and fusion reactors. Efforts are underway to develop high density carbon materials as well as amorphous isotropic carbon for the application in thermal reactors. There has been research on coated nuclear fuel for high temperature reactor and research and development on coated fuels are now focused on fuel particles with high endurance during normal lifetime of the reactor. Since graphite as a moderator as well as structural material in high temperature reactors is one of the most favored choices, it is now felt to develop high density isotropic graphite with suitable coating for safe application of carbon based materials even in oxidizing or water vapor environment. Carboncarbon composite materials compared to conventional graphite materials are now being looked into as the promising materials for the fusion reactor due their ability to have high thermal conductivity and high thermal shock resistance. This paper deals with the application of carbon materials on various nuclear reactors related issues and addresses the current need for focused research on novel carbon materials for future new generation nuclear reactors.

• 천문학회보
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• 제44권1호
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• pp.49.1-49.1
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• 2019

Giant radio relics in the outskirts of galaxy clusters have been observed and they are interpreted as synchrotron emission from relativistic electrons accelerated via diffusive shock acceleration (DSA) in weak shocks of Ms < 3.0. In the DSA theory, the particle momentum should be greater than a few times the momentum of thermal protons to cross the shock transition and participate in the Fermi acceleration process. In the equilibrium, the momentum of thermal electrons is much smaller than the momentum of thermal protons, so electrons need to be pre-accelerated before they can go through DSA. To investigate such electron injection process, we study the electron pre-acceleration in weak quasi-perpendicular shocks (Ms = 2.0 - 3.0) in an ICM plasma (kT = 8.6 keV, beta = 100) through 2D particle-in-cell simulations. It is known that in quasi-perpendicular shocks, a substantial fraction of electrons could be reflected upstream, gain energy via shock drift acceleration (SDA), and generate oblique waves via the electron firehose instability (EFI), leading the energization of electrons through wave-particle interactions. We find that such kinetic processes are effective only in supercritical shocks above a critical Mach number, $Ms{\ast}{\sim}2.3$. In addition, even in shocks with Ms > 2.3, energized electrons may not reach high energies to be injected to DSA, because the oblique EFI alone fails to generate long-wavelength waves. Our results should have implications for the origin and nature of radio relics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.59-62
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• 1991

This paper describes an effective algorithm for evaluating the reliability indices and calculating the production cost for generation system with thermal, hydro and pumped storage plants. Using the Energy Invariance property, this algorithm doesn't need deconvolution process which gives large burden in computing time. In order to consider an adaptable load model, we consider the system load with forecasting uncertainty. The proposed algorithm is applied to the KEPCO system and its result shows high accuracy and less computing time.

• 에너지공학
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• 제8권1호
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• pp.76-84
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• 1999

The demand of Small Self-generating System (SSS) including Small Cogeneration System (SCS) is constantly increasing with the need of electricity and/or thermal in office, hospital, hotel, and small factory, etc. It is especially recommended to operate SCS in the heat-following mode to maximize the efficiency of generator. In case of the heat-following mode SCS has got to be connected to distribution system so as to send surplus power to the utility or receive the short power from utility. But the interconnection of SSS with distribution system causes a few problems such as the bad power quality, and low security. If SSS is not promptly disconnected after faults occur (Islanding of SSS), it can not only damage equipment of utility and adjacent customers but also endanger life of human due to overvoltage or overcurrent. In this paper it has been deeply discussed if interconnection of engine self-generator/control system satisfies the protective requirement for SSS or not. 500 kW engine generator running in the Jodo island has been used to perform the analysis of interconnection.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.192-193
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• 2021

Recently, the need to strengthen the Air Environment Conservation Act and secure alternative heat sources during the winter by carbon neutrality policies has been raised. Accordingly, winter construction, which has safety and quality measures, is emerging as an essential factor. It is believed that eco-friendly tropical type electric hot air heaters will be able to solve most of the problems of winter construction at construction sites, especially prevention of suffocation and fire accidents. In addition, as a result of on-site performance verification, it has secured more than the same performance as the existing curing method, and the curing technology can create an eco-friendly and pleasant working environment while considering safety and construction.

• 에너지공학
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• 제27권3호
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• pp.21-27
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• 2018

제로에너지 건축물 인증제도 시행에 따라 민간부문 활성화 및 보급 확대를 위한 제도의 지속적인 고도화가 이루어지고 있으며, 정부는 공공부문을 시작으로 민간부문에 확대 될 때까지 단계별 의무화 로드맵을 설정하였다. 이에 따라 제로에너지빌딩 인증제의 기반이 되는 건물에너지효율인증 기준에 따른 2016~2017년 기존 건축물들의 에너지소요량을 분석하여 주요 인자 변화에 따른 부하별 연관성에 대해 분석하였다. 기존 건축물중 아파트, 오피스텔 등 주거용을 제외한 중부 및 남부지역 714개 건물을 분류하여 1차 에너지소요량을 분석하였다. 새로운 설계기법들이 적용됨에 따라 패시브측면에서의 에너지요구량은 지속적으로 감소하고 있으며, 신재생에너지 보급 활성화와 연계되어 제로에너지빌딩 시범사업 또한 지속적으로 이루어지고 있는 실정에 제로에너지빌딩 인증 기준을 고도화하기 위해 다양한 방법들을 적용하여 해석할 필요성이 있다고 판단된다.

• Nuclear Engineering and Technology
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• 제45권6호
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• pp.731-744
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• 2013

Energy security is a topic of high importance to many countries throughout the world. Countries with access to vast energy supplies enjoy all of the economic and political benefits that come with controlling a highly sought after commodity. Given the desire to diversify away from fossil fuels due to rising environmental and economic concerns, there are limited technology options available for baseload electricity generation. Further complicating this issue is the desire for energy sources to be sustainable and globally scalable in addition to being economic and environmentally benign. Nuclear energy in its current form meets many but not all of these attributes. In order to address these limitations, TerraPower, LLC has developed the Traveling Wave Reactor (TWR) which is a near-term deployable and truly sustainable energy solution that is globally scalable for the indefinite future. The fast neutron spectrum allows up to a ~30-fold gain in fuel utilization efficiency when compared to conventional light water reactors utilizing enriched fuel. When compared to other fast reactors, TWRs represent the lowest cost alternative to enjoy the energy security benefits of an advanced nuclear fuel cycle without the associated proliferation concerns of chemical reprocessing. On a country level, this represents a significant savings in the energy generation infrastructure for several reasons 1) no reprocessing plants need to be built, 2) a reduced number of enrichment plants need to be built, 3) reduced waste production results in a lower repository capacity requirement and reduced waste transportation costs and 4) less uranium ore needs to be mined or purchased since natural or depleted uranium can be used directly as fuel. With advanced technological development and added cost, TWRs are also capable of reusing both their own used fuel and used fuel from LWRs, thereby eliminating the need for enrichment in the longer term and reducing the overall societal waste burden. This paper describes the origins and current status of the TWR development program at TerraPower, LLC. Some of the areas covered include the key TWR design challenges and brief descriptions of TWR-Prototype (TWR-P) reactor. Selected information on the TWR-P core designs are also provided in the areas of neutronic, thermal hydraulic and fuel performance. The TWR-P plant design is also described in such areas as; system design descriptions, mechanical design, and safety performance.