Browse > Article
http://dx.doi.org/10.14407/jrp.2013.38.2.060

Influence of Modelling Approaches of Diffusion Coefficients on Atmospheric Dispersion Factors  

Hwang, Won Tae (Korea Atomic Energy Research Institute)
Kim, Eun Han (Korea Atomic Energy Research Institute)
Jeong, Hae Sun (Korea Atomic Energy Research Institute)
Jeong, Hyo Joon (Korea Atomic Energy Research Institute)
Han, Moon Hee (Korea Atomic Energy Research Institute)
Publication Information
Journal of Radiation Protection and Research / v.38, no.2, 2013 , pp. 60-67 More about this Journal
Abstract
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.
Keywords
Hypothetical accidental release; Atmospheric dispersion factor; Dispersion coefficient; Plume meandering; Surface roughness;
Citations & Related Records
연도 인용수 순위
  • Reference
1 U. S. Nuclear Regulatory Commission (NRC). Atmospheric dispersion models for potential accident consequence assessments at nuclear power plants. Regulatory Guide 1.145 Revision 1. 1979.
2 Canadian Standards Association. Guidelines for calculating radiation doses to the public from a release of airborne radioactive material under hypothetical accident conditions in nuclear reactors. CAN/CSA-N288.2-M91. Rexdale, Ont. 1991.
3 Jow HN, Sprung JL, Rollstin JA, Ritchie LT, Chanin D. MELCOR accident consequence code system (MACCS): Model description, NUREG/CR-4691, SAND86-1562. Sandia National Laboratories. 1990.
4 Chanin D, Young ML, Randall J, Jamali K. MELCOR accident consequence code system for the calculation of the health and economic consequences of accidental atmospheric radiological release (MACCS2) : User's guide, NUREG/CR-6613, SAND97- 0594. Sandia National Laboratories. 1998.
5 원자력안전위원회. 원자로시설 부지의 기상조건에 관한 조사.평가 기준, 원자력안전위원회고시 제2012- 19호. 2012.
6 Till JE, Meyer HR. Radiological assessment: A text on environment dose analysis, NUREG/CR-3332, ORNL-5968. U. S. Nuclear Regulatory Commission (NRC). 1983.
7 Snell WG, Jubach RW. Technical basis for regulatory guide 1.145, "Atmospheric dispersion models for potential accident consequence assessments at nuclear power plants", NUREG/CR-2260, NUS-3854. U. S. Nuclear Regulatory Commission (NRC). 1981.