In this contribution we discuss analytical modelling of radioactive substance dispersion that results from either controlled or accidental release by nuclear power plants. Our model is based on the three-dimensional advection-diffusion equation with mean wind velocity field from observation. All meteorological parameters are determined using the meso-scale Weather Research and Forecasting (WRF) platform. The obtained solution permits us to simulate radioactive substances dispersion in a turbulent regime in the environment around a power plant, which is of interest for nuclear reactor accident scenarios and their related emergency actions.We discuss the closed form method for solving the equation which is then applied to radioactive substance dispersion. Finally, the results of the model are presented.