An examination on variations in ground level concentrations due to atmospheric releases of radioactive materials for different terrain

Radioactive material consequent to filtration released in the environment through the stack are transported by wind and diffused by turbulence present in the atmosphere. Diffusion of radioactive material takes place in the direction of the mean wind flow and simultaneously dispersed in the crosswind and vertical directions. Dispersion of plume is basically governed by wind speed and intensity of turbulence in the atmosphere. In case of radiological impact assessment, atmospheric dispersion model like Gaussian Plume Model (GPM) assumes the basic parameters σy and σz (dispersion coefficients in lateral and vertical direction) for computation of concentration in radioactive plume at different receptors location. In this study, the variation in ground level concentrations due to elevated releases has been estimated using GPM for flat and rough terrain considering widely accepted Briggs sigma scheme (dispersion coefficient). Briggs sigma's are assumed to be very effective for the receptors close to the release point