A virtual source model for building wake dispersion in nuclear safety calculations

The suitability of a virtual source building wake dispersion model for use in estimating near field air concentrations of activity due to the atmospheric discharge of radionuclides from nuclear power stations is discussed. Simple prescriptions for the application of the model are developed and the model's predictions are compared with a limited amount of experimental data. The advantages and limitations of simple models in general and the virtual source model in particular are identified by comparing the assumptions inherent in simple models with the physical processes which govern air flows in building wakes. Finally, conclusions are drawn as to the range of applicability of the model, together with estimates of the model's predictive accuracy. (author)