Deposition velocity and washout coefficient of radionuclides bound to aerosol particles and elemental radioiodine

The deposition of radionuclides bound to aerosol particles and of radioiodine can be predicted with the aid of theoretical models whenever the radioactivity distribution relative to particle size and the meteorological conditions are known or can be estimated. The calculated dry deposition is compared with the measured dry deposition of particle bound radionuclides and radioiodine after the Chernobyl accident. As the most important input parameters were monitored, this comparison was a good validation of the model developed during recent years. The washout coefficient of aerosol particles is modelled as a function of the activity-size distribution and the rainfall intensity. The measurements following the Chernobyl accident agree with the predicted relationship between the washed out radioactivity concentration in the rainwater and the rainfall intensity. (author)