Abstract: The paper introduces the first integrated real-time assessment system for nuclear emergency at uranium enrichment facility in China. The system can assess the radiation effects of nuclear criticality accidents and UF₆ leakage accidents in a real-time manner. It estimates nuclear criticality fission number according to the readings of γ alarm dose rate instrument, and automatically assess the nuclear criticality consequence. Focusing on the heavy gas characteristic of UF₆ plume, the system combines the heavy gas model with the Gaussian model, thus simulates more accurately the UF₆ diffusion process. The development of the system solves the problem of lacking the technical support capability for uranium enrichment facility in emergency preparedness and response.

Key words: uranium enrichment facility, nuclear emergency assessment system, protective action