Experiment and Simulation of Cloud Source Term of Nuclear Material Produced by High-explosive Detonation

The process and mechanism of cloud diffusion in nuclear material chemical explosion accidents were analyzed in this paper to obtain the parameters of the cloud and the aerosol diffusion law. A numerical simulation method for cloud diffusion based on CFD technology was established. The simulation method was verified by conducting an external field diffusion experiment of the explosion cloud. The results show that the simulation of cloud diffusion can be realized by CFD method. The experimental and simulated clouds show that the explosion height of small equivalent TNT is much smaller than that of Church’s empirical formula, and the width ratio increases. The aerosol particles are unevenly distributed in the flow field of the mushroom double-vortex ring cloud. The particles with size greater than 50 μm are mostly located in the cloud column, while most of the respirable particles are concentrated at the top of the cloud. The aerosol source term parameters are changed by the dispersal and sedimentation before the cloud is stabilized. The calculation of the aerosol accumulation mass distribution in the Operation Roller Coaster experiment shows that the airborne release fraction is about 58% of the surface gasification rate, the respirable fraction increases from 20% to 31%, and the respirable release fraction is about 18%.