Assessment and Validation of the Sevex Project

The SEVEX Project has been developed to assess the contamination zones in complex areas, subsequent to an accidental (hypothetical) release of hazardous materials at industrial sites. It is divided into three interlinked modules (source, meteorological and dispersion), the output of which can be used by public authorities for the evaluation of risk areas and the preparation of emergency planning. The source module takes into account instantaneous and continuous releases and the short distance dispersion of dense or neutral gases. The two modules integrating the topography are the meso-meteorological module and the dispersion module. The velocity,turbulence and concentration fields are three dimensional. The source and the meteorological modules have been tested, and the results of the validations published. The dispersion module is based on a particle approach and uses the output of the other modules. Comparisons between the numerical results from our model and from Gaussian models are presented. A validation based on the results deduced from tracer experiments (near Karlsruhe and in the Nevada desert) and numerical results of the SEVEX Project is analysed. Potential risk sites with regard to the European 'Seveso' directive have been chosen in the Walloon Region.