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        검색결과 6

        1.
        2022.05 구독 인증기관·개인회원 무료
        With the increase of temporarily-stored spent radioactive fuels, there is an increasing necessity for the safe disposal of high-level radioactive waste (HLW). Among various methods for the disposal of HLW, a deep geological disposal system is adapted as a HLW disposal strategy in many countries. Before the construction of a repository in deep geological condition, a performance assessment, which means the use of numerical models to simulate the long-term behavior of a multi-barrier system in HLW repository, has been widely performed to ensure the isolation of radionuclides from human and related environments for more than a million years. Meanwhile, Korea Atomic Energy Research Institute (KAERI) is developing a process-based total system performance assessment framework for a geological disposal system (APro). To improve the reliability of APro, KAERI is participating in DECOVALEX-2023 Task F, which is the international joint program for the comparison of the models and methods used in deep geological performance assessment. As a final goal of Task F, the reference case for a generic repository in fractured crystalline rock is described. The three-dimensional generic repository is located in a domain of 5 km in length, 2 km in width, and 1 km in depth, and contains an engineering barrier system with 2,500 deposition holes in fractured crystalline rock. In this study, a numerical simulation of the reference case is performed with COMSOL Multiphysics as a part of Task F. The fractured crystalline rock is described with the discrete fracture matrix (DFM) model, which expresses major deterministic fractures explicitly in the domain and minor stochastic fractures implicitly with upscaled quantities. As an output of the numerical simulation, fluid flow at steady-state and radionuclide transport are evaluated for ~106 years. The result shows that fractures dominate the transport of radionuclides due to much higher hydraulic properties than rock matrix. The numerical modeling approaches used in this study are expected to provide a basis for performance assessment of nuclear waste disposal repository located in fractured crystalline rock.
        2.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we numerically analyzed flow and particle transport near the electrostatic precipitator in the tunnel according to train runs. When there was no train running, flow field was formed by a precipitator. Flow emitted from precipitator blocks the path along the tunnel, and therefore most contaminated air passes through the precipitator and can be cleaned. On the other hand, flow pattern during the train run was affected by train induced wind. A strong straight flow was generated at the front of train, and back flow was formed in the opposite line. When a train runs upward only (train start from suction section to blow section), the subway train transports contaminated particles along the tunnel. For downward train runs only case, the cleaned air reentered the contaminated section with train wind. Both train runs case showed combined flow and particle concentration pattern of both single train runs.
        4,000원
        3.
        2012.03 KCI 등재 서비스 종료(열람 제한)
        남강댐 하류는 부산·경남의 수자원 장기 계획에 중요한 지역이므로 지속가능한 지표수 관리 및 오염원 제어를 위해 흐름 및 수질 해석이 필요하다. 따라서 본 연구에서는 2차원 수질모형인 RAM4와 3차원 수질모형인 WASP을 각각 수리모형인 RAM2 및 EFDC모형과 연계하여 2·3차원 준연계 모형을 이용한 남강댐 하류에서의수리 및 수질을 해석하였다. 2차원 흐름해석 모형인 RAM2 적용 결과 만곡부 5개 횡단 측선에서의 유속의 증감경향이 ADCP 실측값과 잘 일치하였으며, 3차원 모형인 EFDC와 유속 분포 및 보 월류 유속이 유사하였다. 또한 정상상태 도달 후의 RAM2-RAM4 연계모의에 의한 BOD 농도와 EFDC-WASP 연계모의에 의한 BOD 농도장이 모의영역 전반에 걸쳐 유사하게 나타났다. 남강댐 하류부의 경우 수리 및 수질이 남강댐 방류량에 크게 좌우되며 남강댐의 수량은 하류부의 수질 및 연안 어업환경에 큰 영향을 미치므로 향후 이에 대한 정량적 분석 시 계산의 효율성 및 모형의 적용성 측면에서 2차원 준연계 모형을 적용하는 것이 바람직한 것으로 판단된다.
        4.
        2002 서비스 종료(열람 제한)
        The flow zone through jets are used in evaluating the environmental and constructional effects of navigation on the Kwangyang navigation channel. It is relies on the characteristics of ships and water depth. A numerical model using the momentum theory of the propeller and Shield's diagram was developed in a restricted waterway. Equations for discharge are presented based on thrust coefficients and propeller speed and are the most accurate means of defining discharge. Approximate methods for discharge are developea based on applied ship's power. Equations for discharge are as a function of applied power, propeller diameter, and ship speed. Water depth of the waterway and draft of the ship are also necessary for the calculation of the grain size of the initial motion. The velocity distribution of discharge from the propeller was simulated by the Gaussian normal distribution function. The shear velocity and shear stress were from the Sternberg's formula. Case studies to show the influence of significant factors on sediment movement induced by the ship's propeller at the channel bottom are presented.
        5.
        1998.06 KCI 등재 서비스 종료(열람 제한)
        균열 암반 매질에서의 지하수 흐름과 오염물질 이송에 대한 수치모의 실험이 hydromechanic 모형과 추계적 그리고 이산적 3차원 균열망 모형에 바탕을 둔 비정상상태 흐름 수치 모형을 이용하여 수행되었다. 오염물질 이송에 대한 수치모의 실험에서 random walk의 일종인 particle following 알고리즘이 사용되었다. 이 연구의 목적은 지하 깊은 곳에 위치한 Hot dry rock에서의 지열 개발을 위해 프랑스 Soultz sous Fo
        6.
        1997.12 KCI 등재 서비스 종료(열람 제한)
        밀도가 변하는 지하수의 흐름과 용질의 수송 현상을 정확히 모델링할 수 있는 수치모델을 개발하였다. 수치모델의 정확도는 이송이 지배적인 경우에 발생하는 수치진동을 피할 수 있어야 얻을 수 있다. 이를 위하여 변분법에 기초한 비선형 수치진동흡수 유한요소법을 적용하였다. 개발된 수치모델은 기존 수치모델들과 달리 확장성이 뛰어나다. 본 수치모델의 정확도를 해석해와 다른 수치모델 결과와 비교하여 평가하였다.