Buoyant Gaussian Plume Modeling of atmospheric Dispersion of Cs-137 Emitted from a Nuclear Reactor

Abstract

A two dimensional Advection-Diffusion equation was developed to model atmospheric dispersion of Cs-137 in order to visualize the phenomenon of the transport ofCs-137 in the atmosphere. The study was also aimed at analyzing the activity concentration of Cs-137 and examined the mathematical approaches for determining the mass concentration of Cs-137 released to the atmosphere. The Buoyant Gaussian model was examined and a finite difference scheme was developed to solve the partial differential equations of radionuclide pollution transport in the atmosphere. The model program code for Gaussian Plume was implemented by using the MATLAB interface contouring software. The result outputs showed that like other parameters, depth has significant influence on the dispersion of pollutants; the highest and least activity concentrations of Cs-137 dispersion were found to be 0.4686 𝑚𝑔/𝑚3and 0.0002 𝑚𝑔/𝑚3 at 2.5 𝑚/𝑠 respectively. The maximum distance that was covered by Cesium-137 from the source downwind was 1621m at 5m/s. In the event of an accidental atmospheric release of radionuclides from a nuclear power plant, accurate forecasting of the dispersion and the activity concentrations of radionuclides are required for the preparation of adequate countermeasures and evacuation.