| Influence to the environment of radioactivity gaseous effusion in the nuclear power plant is always under observation of the government and the international organization. Current guide rules of atmospheric dispersion in normal operation and accident condition based on the Gaussian model, which is difficult to use to estimate the dispersion in the situation of complex terrain and structures, especially in the inland nuclear power plant with cooling tower. In response to this situation, aiming at the dispersion in different atmospheric stability and complex terrain, this paper mainly investigates the following sections:Build three-dimensional model of site area with 2km radius, and then use the method of numerical simulation to calculate the inner 3D onflow field wth CFD software. In order to study the dispersion parameters of 3D turbulent field in different atmospheric stability, the method of Time-Average flow analysis are used.To build reality modelof QINSHAN nuclear power plant, terrain and structures are added on the basic of numerical model as effect factors of dispersion. Concentration field in three classic atmospheric stability are analysed by compareing with the results of Gaussian model and SF6 tracer experiment, which shows that CFD simulation could generate better results than Gaussian model.In the study of inland nuclear power plant, numerical model with cooling tower are built, which put three constituent and laminarization of atmospheric thermal into consideration. The dispersion parameters are analysed in this condition, and the results indicate that the cooling tower has serious influence to the dispersion in the region of nuclear power plant.In this paper, the study method of dispersion in three-dimensional air thermal numerical model in nuclear power plant are mastered, which lay a foundation of CFD numerical simulation of dispersion in the situation of complex terrain and structures, especially in the inland nuclear power plant with cooling tower.
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