Evaluating the effect of nuclear power plant buildings on the atmospheric dispersion behavior of released radioactive materials

Abstract EN

One of the most important principles in air pollution is to minimize the release of pollutants to the atmosphere, deposition on the ground and promote sufficient dilution of released pollutants within the atmosphere.

Building downwash describes the effect that wind flowing over or around buildings create a cavity of reticulating winds in the area near the buildings.

These cavities cause increased vertical dispersion of plumes emitted from stacks on or near the buildings.

Often it leads to elevated concentrations downwind of affected stacks.

The aim of this work is to evaluate the effect of the building downwash phenomena on the atmospheric dispersion behavior of released radioactive materials from NPP.

In this study, a hypothetical scenario is presented involving a point source with varying stack parameters and rectangular shaped buildings (Millestone Nuclear Power Plant) using meteorological parameters of a chosen day.

The concentrations of assumed released radionuclides, taking into consideration the building downwash effect and without are calculated using the AERMOD Model taking into consideration the effect of the type of atmospheric stability class.

Also the analysis includes the model predictions for the highest 1- hour cavity concentration.

The results show that the size of the cavity zone is not affected by the type of stability class, but is affected by the stack location and buildings shape.

On other hand, the distance at which the plume touches the ground is affected by the type of stability class, the stack location and buildings shape.

So, strategies for locating buildings need to be considered to maximize dispersion when planning for constructing several reactors and accessory buildings at a nuclear site.