Study on the Diffusion Law of Radionuclides Based on the Improved Gaussian Plume Model

This study aims to improve the prediction accuracy of the diffusion trajectory of radioactive pollutants in the atmosphere. First, based on the traditional Gaussian plume model, the model is improved by introducing two key control factors: rainfall intensity and ground roughness. Secondly, the factors affecting gas diffusion under different rainfall intensities and ground roughness are analyzed, as well as the diffusion characteristics of radioactive pollutants in the atmosphere under the influence of these two factors. Finally, taking the radioactive nuclide leakage of Daya Bay Nuclear Power Station as an example, according to the analysis of the concentration distribution characteristics in the downwind and crosswind directions, the results show that rainfall intensity and ground roughness have a significant effect on the diffusion concentration and diffusion range of radioactive nuclides. With the increase of rainfall intensity and the improvement of ground roughness, the diffusion concentration is significantly reduced, and the area of the dangerous area is significantly reduced. Compared with the traditional simulation results, the improved model is reasonable and has certain guiding significance, which provides a scientific basis for nuclear accident emergency response and risk assessment.