THE UK NUCLEAR ACCIDENT MODEL

An account is given of the U.K. Meteorological Office numerical model for simulating the long range transport, dispersion and wet and dry deposition of radionuclides to the ground following an accidental release into the atmosphere. The Met. Office was supported in this project by the Safety and Reliability Directorate of the UKAEA and two University Research groups. A fairly full description is given of the structure of the model and its modus operandi, in particular the parametrization of the diffusive, entrainment and deposition processes. The model features a unique high-resolution, real-time rainfall archive underpinning the wet deposition, and a substantially automated technique for adjusting the model assumptions and products in the light of observed radiology. The paper concludes with some examples of model applications which include the Kuwait crisis and Chernobyl.