(A) study on the effeet of simple terrain on the atmospheric dispersion of radionuclides

Abstract

In a Nuclear Power Plant(NPP) severe accident, radionuclides are released into the atmosphere with extremely high concentration above their normal amount. The mechanisms of dispersion of released materials are diffusion and transport. In this work, we use the Gaussian puff diffusion equation to compute the contribution to the concentration at each receptor from each puff every time step(15 min). The scale of Gaussian puff diffusion model is from tens of meters to tens of kilometers. Most of the Korean NPP``s are located on the coastal regions, and the surrounding terrain around the sites are usually very complex and hilly. So in this work, we have studied on the effect of simple terrain on the atmospheric dispersion of radionuclides. Sensitive analysis has been performed for 8 input parameters. The simple terrain causes high ground-level concentrations to be experienced when the puff is dispersed close to the simple terrain. This model is applied to an intermediate-level emergency dose assessment computer code.