• Title, Summary, Keyword: 대기확산인자

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월성원전 부지의 가을철 방사성 물질의 대기확산인자 분포 특성

  • 이갑복;이명찬;송영일
    • Proceedings of the Korean Nuclear Society Conference
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    • pp.665-670
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    • 1998
  • 삼차원 해륙풍 모델과 라그랑지안 입자확산모델을 이용하여 해안지역에 위치한 원전으로부터 정상운전시 장기적으로 연속 방출되는 방사성 물질의 대기확산 평가방법론을 개발하였다. 개발된 방법론을 적용하여 월성원전 부지를 대상으로 풍향, 풍속 및 운량에 따라 범주화된 각 종관기상 상태에 대해 가을철 방사성 물질 대기확산 특성을 분석하였다. 분석 결과, 방사성 물질의 계절 또는 연중 핑균적인 대기확산인자의 분포는 종관바람 둥과 같은 주풍의 발생빈도에 영향을 받을 뿐만 아니라, 해륙풍 등과 같은 국지 대기순환의 특성에 따라서도 그 분포특성이 결정됨을 알 수 있었다.

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Influence of Modelling Approaches of Diffusion Coefficients on Atmospheric Dispersion Factors (확산계수의 모델링방법이 대기확산인자에 미치는 영향)

  • Hwang, Won Tae;Kim, Eun Han;Jeong, Hae Sun;Jeong, Hyo Joon;Han, Moon Hee
    • Journal of Radiation Protection and Research
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    • v.38 no.2
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    • pp.60-67
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    • 2013
  • A diffusion coefficient is an important parameter in the prediction of atmospheric dispersion using a Gaussian plume model, and its modelling approach varies. In this study, dispersion coefficients recommended by the U. S. Nuclear Regulatory Commission's (U. S. NRC's) regulatory guide and the Canadian Nuclear Safety Commission's (CNSC's) regulatory guide, and used in probabilistic accident consequence analysis codes MACCS and MACCS2 have been investigated. Based on the atmospheric dispersion model for a hypothetical accidental release recommended by the U. S. NRC, its influence to atmospheric dispersion factor was discussed. It was found that diffusion coefficients are basically predicted from a Pasquill- Gifford curve, but various curve fitting equations are recommended or used. A lateral dispersion coefficient is corrected with consideration for the additional spread due to plume meandering in all models, however its modelling approach showed a distinctive difference. Moreover, a vertical dispersion coefficient is corrected with consideration for the additional plume spread due to surface roughness in all models, except for the U. S. NRC's recommendation. For a specified surface roughness, the atmospheric dispersion factors showed differences up to approximately 4 times depending on the modelling approach of a dispersion coefficient. For the same model, the atmospheric dispersion factors showed differences by 2 to 3 times depending on surface roughness.

Meteorological Preprocessor Validation of Atmospheric Dispersion Model (대기확산모델의 기상전처리과정의 타당성 평가)

  • 김미숙;주철균;이종협
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • pp.137-138
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    • 2003
  • 한국 환경부가 지원하는 대기오염확산모델 SKYi는 통합환경관리의 일환으로서 대기오염배출규제강화와 미래 대기질의 예측뿐만 아니라 환경관리의 입법적인 수행을 목적으로 개발 중에 있다. SKYi는 기상과 배출 그리고 지형에 대한 전처리과정의 서브프로그램과 연결되는데, 본 연구는 기상전처리과정의 모듈 SKYME 개발에 중점을 둔다. 이는 기상전처리모듈에서 산출된 혼합고도와 같은 기상인자가 대기오염확산의 물리적인 특성으로서 효율적인 대기오염농도예측에 중요한 역할을 하기 때문이다. (중략)

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Influence of Statistical Compilation of Meteorological Data on Short-Term Atmospheric Dispersion Factors in a Hypothetical Accidental Release of Nuclear Power Plants (기상자료의 통계처리방법이 원자력발전소의 가상 사고시 단기 대기확산인자에 미치는 영향)

  • Hwang, Won-Tae;Kim, Eun-Han;Jeong, Hae-Sun;Jeong, Hyo-Joon;Han, Moon-Hee
    • Journal of Radiation Protection and Research
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    • v.37 no.3
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    • pp.116-122
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    • 2012
  • A short-term atmospheric dispersion factor (${\chi}/Q$) is an essential element for radiological dose assessment following a hypothetical accidental releases of light-water nuclear power plants. The U. S. NRC developed PAVAN program to comply with the U. S. NRC's Regulatory Guide 1.145. Meteorological data is an essential element for atmospheric dispersion, and PAVAN uses a joint frequency distribution data, which represents the occurrence probability of wind speed and wind direction for atmospheric stability. Using the meteorological data measured at Kori and Wolsung sites for the last 5 years (from 2006 to 2010), a variety of joint frequency distribution data were prepared to evaluate ${\chi}/Q$ values with different wind speed classifications (U. S. NRC's recommendation and even distribution of occurrence probability) and periods of meteorological data to be analyzed (1 year, 2 year, 3 year, 4 year, 5 year). As a result, it was found that the influence of the wind speed classification on ${\chi}/Q$ values is little, while the influence of the periods of meteorological data to be analyzed is relatively significant, representing more than 1.5 times in the ratio of maximum to minimum values.

Analysis of Particulate Distribution Emitted from the Stack of the Casting Furnace near by Seashore (해안에 위치한 주조공장 용해로 스택에서 배출되는 입자상 오염물의 분포에 관한 분석)

  • 안시찬;이병규
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • pp.209-210
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    • 2001
  • 공장 굴뚝이나 차량과 같은 오염원에서 배출된 오염물질은 대기 중에서 확산과정을 거쳐 수용체(Receptor)에 도달하여 영향을 미치게 되는데, 확산을 결정하는 주요인자로는 오염물 배출조건 및 농도, 대기 기상조건, 주변지형조건, 오염물의 반응성 및 침착성 등이 있다. 대기환경 영향평가 및 대기질 관리성책수립 등을 위해서 복잡한 대기확산 과정을 거쳐서 수용체에 도달하는 오염물질의 농도에 대한 정량적인 값의 추정이 필요하다. (중략)

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Influence of Calm Conditions on the Atmospheric Dispersion of Radioactive Effluents at KAERI Site (한국원자력연구소 부지에서 방사성물질의 대기확산에 대한 정온상태의 영향)

  • Hwang, Won-Tae;Suh, Kyung-Suk;Kim, Eun-Han;Choi, Young-Gil;Han, Moon-Hee;Cho, Gyu-Seong
    • Journal of Radiation Protection and Research
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    • v.23 no.2
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    • pp.103-107
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    • 1998
  • The influence of calm conditions on the atmospheric dispersion analyses at KAERI site, which is located at a complex inland basin, was investigated. The U. S. NRC's computer programs XOQDOQ and PAVAN were used to estimate dispersion factors for routine and postulated accidental releases from nuclear facilities, respectively. The joint frequency distribution was obtained from the annual meteorological data measured in 1997 and used as input data of the computer programs. When the definition of calm is changed from 0.5 m $sec^{-1}$ to 0.21 m $sec^{-1}$, the maximum sector dispersion factor becomes 1.62 and 2.16 times higher for routine and postulated accidental releases, respectively.

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Atmospheric Dispersion Assessment for Potential Accidental Releases at Yonggwang Nuclear Power Plants (영광원전에서 가상 사고시 대기확산 평가)

  • Na, Man-Gyun;Sim, Young-Rok;Jung, Chul-Kee;Lee, Goung-Jin;Kim, Soong-Pyung;Chung, Sung-Tai
    • Journal of Radiation Protection and Research
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    • v.25 no.2
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    • pp.81-87
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    • 2000
  • XOQ_DW code is currently used to assess the atmospheric dispersion fur the routine releases of radioactive gaseous effluents at Yonggwang nuclear power plants. This code was developed based on XOQDOQ code and an additional code is required to assess the atmospheric dispersion for potential accidental releases. In order to assess the atmospheric dispersion fer the accidental releases, XOQAR code has been developed by using PAVAN code that is based on Reg. Guide 1.145. The terrain data of XOQ_DW code inputs and the relative concentrations (X/Q) of XOQ_DW code outputs are used as the inputs of the XOQAR code through the interface with XOQ_DW code. By using this code, the maximum values of X/Q at exclusion area and low population zone boundaries except for sea areas were assessed as $1.33{\times}10^{-4}$ and $7.66{\times}10^{-6}$ sec/$m^3$, respectively. Through the development of this code, a rode system is prepared for assessing the atmospheric dispersion for the accidental releases as well as the routine releases. This developed code ran be used for other domestic nuclear power plants by modifying the terrain input data.

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Data Assimilation Techniques Applied to Estimate the Dispersion of the Pollutant in the Atmosphere (자료동화기술을 이용한 대기중 오염물질 확산평가)

  • 한문희;정효준;김은한;서경석;황원태;이선미
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • pp.368-376
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    • 2004
  • The estimation of the diffusion coefficients of the Gaussian plume model and the release rate by assimilation of tracer-gas measurements on Younggwang site was tested. Diffusion coefficients were modified by linear programming of both the measurements and the simulated using the Gaussian plume model. The application of the modified diffusion coefficients improved the prediction ability of the Gaussian plume model on both 3 km and 8 km arc lines. And, the release rate of tracer gas was estimated using least squares method. The optimal source rate was estimated by minimizing the errors between the measured concentrations and the computed ones by the Gaussian plume model. The obtained release rate showed a good agreement with the real release rate of the Younggwang experiment in 24%.

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