Consequence assessment of plutonium aerosol diffusion after chemical explosion accident in an underground facility

Abstract The aerosolization and diffusion of radioactive materials caused by chemical explosions represent a typical nuclear accident scenario that poses severe radioactive hazards to human health and the environment. This study examines the diffusion of plutonium aerosol generated by a chemical explosion within a typical representative underground facility. The state of explosion products following a single-point detonation of explosives was simulated. Subsequently, a numerical simulation of plutonium aerosol diffusion using the discrete phase model (DPM) was conducted based on the outcomes of the chemical explosion simulation. The simulation results indicate that plutonium aerosols diffuse throughout underground facilities after a chemical explosion; small particle size aerosols primarily accumulate in the upper part of the room after the accident; the concentrations of plutonium aerosol in the room and tunnel are significantly higher than those in the other areas; and the temporal variations in aerosol concentration in each area were quantified. Based on the particle concentration distribution and the effective dose computation approach, the study computes the internal irradiation dose received by personnel in seven areas over various time periods post-accident. Recommendations for emergency decision-making were derived from these calculations. These findings provide important theoretical insight and practical engineering application value for understanding the diffusion of radioactive aerosol in confined spaces following chemical explosions and for evaluating personnel radiation dose.