MODELLING BUILDING EFFECTS ON ATMOSPHERIC DISPERSION. COMPARISON BETWEEN ADMS AND ANSYS CFD

摘要

This paper presents the preliminary results of a comparative study regarding the radionuclides transport around the reactor building of a Nuclear Power Plant (NPP). The aim of our work was to assess the accuracy of the RANS (Reynolds Averaged Navier-Stokes) CFD (Computational Fluid Dynamics) model developed for a continuous pollutant stack release by comparing the CFD results against the ADMS Gaussian distribution. The Ansys CFX code was set up to simulate a stable atmospheric boundary layer using the six-equation Reynolds stresses turbulence model and the Lagrange Particle Tracking (LPT) method for pollutant dispersion. The two codes were compared in terms of concentrations and plume spread at ground level for five stack-building positions relative to the mean wind direction. The main finding is that the difference between the two set results is below a factor of two depending on the building position.