Long-Range Transport of Large Particles Released During a Nuclear Accident

Abstract

In case of a nuclear accident such as an explosion or a fire in a nuclear power plant, a significant part of the refractory radionuclides is emitted to the atmosphere in the form of particulate matter. Existing dispersion models take only partly this fact into account, assuming that only small size (diameter of ∼1 μm) particles are subject to long-range transport in the air. Large particles (diameter 10 μm) are usually not included in most long-range transport models, assuming that they are deposited relatively close to the sources. A typical assumption in these models is the assignment of one dry deposition velocity to each radionuclide. This means that each radionuclide is transported and deposited as a separate small particle, whereas in reality several radionuclides are imbedded in particles and can be transported as large particles.