An Emergency Evacuation Model for Avoiding High Nuclide Concentration Areas in Nuclear Accident

This paper proposes a nuclear accident emergency evacuation model based on nuclide concentration field and traffic flow network model. Gaussian puff model, which describes the instantaneous concentration of nuclide, is widely used to predict the diffusion of radionuclides in nuclear accidents. We adopt a modified Gaussian puff model to preserve the time characteristics of nuclide diffusion, which considers the effects of dry deposition (gravity deposition), wet deposition (rain wash), and nuclide decay on the concentration distribution. An A-star algorithm based on nuclide concentration and traffic pressure cost is proposed to formulate the optimal path planning under nuclear accident. With the expansion of the nuclide concentration field, more and more paths cannot be safely passed through, and evacuation vehicles will also cause congestion on the path. The evacuation model we proposed will regularly update the optimal route according to road traffic conditions and nuclide spatial distribution, so as to obtain an optimized evacuation strategy. This study takes a real road network around the nuclear power plant as the application scenario of evacuation simulation. The computation time of the evacuation model is short, so it can respond quickly in the event of a nuclear emergency. The results show that the evacuation strategy formulated by the model can ensure good evacuation efficiency and avoid areas with high nuclide concentrations during the evacuation process, thereby reducing the radiation exposure of personnel.