Analysis of experimental campaigns on atmospheric transferts around the AREVA NC spent nuclear fuel reprocessing plant at La hague : Comparison between operational models and measurements
Congress title :11th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes
Congress town :Cambridge
Congress date :02/07/2007
The harmfulness of pollutants emitted into the atmosphere depends mainly on their ability to become fixed and their concentration in the air. This depends of course on the quantities released, but the state of the atmosphere which conditions the future of these pollutants may also be significant: they can be dispersed (vertically and horizontally), transformed by chemical reactions and deposited (dry and wet depositions).
Institute for Radiological Protection and Nuclear Safety (IRSN) is developing its own dispersion and atmospheric transfer tools for its operational needs during an emergency radiological situation. It is also performing field experiments like around the AREVA NC spent nuclear fuel reprocessing plant at La Hague (North West of France). The ultimate aim of the experiments is to reduce the uncertainties over the models of atmospheric dispersion and deposition of gases and aerosols emitted by the nuclear industry in normal operating or accidental situations.
Series of environmental campaigns were carried out around the AREVA NC reprocessing plant to have knowledge on atmospheric transfers in La Hague ecosystem. Bioindicators (furzes, grasses) were sampled to have information of the surface radioactivity of the flora for various radionuclides (iodine-129, tritium, carbon-14) released in the form of gases and aerosols. The campaigns results are analysed and compared with the radioactivity releases from the nuclear plant and provide a basis for estimating the atmospheric dispersion parameters and the deposition parameters that may be used in the operational models for the La Hague site.
The purpose of this paper is to present the results of the radionuclide concentrations obtained during the field campaigns and to compare them with the results from the dispersion and deposition operational models.