Research on Atmospheric Dispersion Factor Used in the Calculation of Emergency Planning Zone

Abstract

AbstractReasonable division of emergency planning zones is an important technical basis for emergency preparedness and responses. In order to evaluate the size of the emergency planning zone, it’s important to determine the appropriate atmospheric dispersion factor based on the realistic site conditions to calculate the dose consequences caused by the accident through the radioactive plume. This paper introduces the current progress in the calculation of emergency planning zoning for different reactor nuclear power plant sites, the general method of determining the emergency planning zone in China and puts forward the method for optimizing the calculation of the atmospheric dispersion factor used in the emergency planning zoning for HPR1000 nuclear power plant site. Based on the theoretical analysis and comparison of the current main calculation models of atmospheric dispersion factor, this paper is devoted to the feasibility analysis of use of Gaussian puff models in the EPZ calculation considering the light wind and the calm wind condition, which can obtain the convergence results. This model can fully consider the dispersion process, spatial variation of meteorological fields, topographic effects and accumulation of pollutants and greatly improve the calculation accuracy. To solve the problems of low calculation speed brought by Gaussian puff models used in the EPZ calculation, the paper makes a theoretical analysis of the current main weather sampling methods and puts forward the stratified random sampling method to improve the speed of EPZ calculation. This method can select representative weather samples from the annual weather sequences to represent the annual situation so as to speed up the calculation without affecting the calculation accuracy.