The estimation of atmospheric dispersion at nuclear reactor plants utilizing real time anemometer statistics

Abstract

Dispersion and turbulence measurements were conducted in a simulated atmospheric boundary layer. Field experiments and wind tunnel results for the behavior of lateral plume dispersion are compared to three semi-empirical expressions based on the Taylor's diffusion theory. These relations imply a direct connection between dispersion coefficients and the Lagrangian integral time scale. Agreement between the field data and laboratory measurements supports using wind tunnel results to simulate atmospheric transport phenomena. Eulerian space-time correlations with streamwise separation were measured for all three velocity components in the simulated boundary layer. Results were compared to previous measurements which were performed under different flow configurations. A universal shape of the Eulerian space-time correlation seems to exist when presented in a normalized time coordinate. Turbulence measurements of fixed-point Eulerian velocity statistics were employed to estimate the Lagrangian velocity statistics through the Baldwin and Johnson approach. The approach was modified to account for the uniform shear stress effect in a homogeneous turbulent flow field. The estimated Lagrangian integral time scale agrees with estimates inferred from dispersion measurements within only a 20% error. Such agreement supports the methodology of using real time anemometer statistics to predict the atmospheric turbulent dispersion near a nuclear reactor site.