A study of the atmospheric dispersion of a high release of krypton-85 above a complex coastal terrain, comparison with the predictions of Gaussian models (Briggs, Doury, ADMS4)
Résumé
Atmospheric releases of krypton-85, from the nuclear fuel reprocessing plant at the AREVA NC facility at La Hague (France), were used to test Gaussian models of dispersion. In 2001-2002, the French Institute for Radiological Protection and Nuclear Safety (IRSN) studied the atmospheric dispersion of 15 releases, using krypton-85 as a tracer for plumes emitted from two 100-m-high stacks. Krypton-85 is a chemically inert radionuclide. Krypton-85 air concentration measurements were performed on the ground in the downwind direction, at distances between 0.36 and 3.3 km from the release, by neutral or slightly unstable atmospheric conditions. The standard deviation for the horizontal dispersion of the plume and the Atmospheric Transfer Coefficient (ATC) were determined from these measurements. The experimental results were compared with calculations using first generation (Doury, Briggs) and second generation (ADMS 4.0) Gaussian models. The ADMS 4.0 model was used in two configurations; one takes account of the effect of the built-up area, and the other the effect of the roughness of the surface on the plume dispersion. Only the Briggs model correctly reproduced the measured values for the width of the plume, whereas the ADMS 4.0 model overestimated it and the Doury model underestimated it. The agreement of the models with measured values of the ATC varied according to distance from the release point. For distances less than 2 km from the release point, the ADMS 4.0 model achieved the best agreement between model and measurement; beyond this distance, the best agreement was achieved by the Briggs and Doury models. © 2010 Elsevier Ltd.
Mots clés
Air concentration measurements
Atmospheric conditions
Atmospheric dispersion
Atmospheric release
Built-up areas
Coastal terrain
Complex terrains
French Institute
Gaussian model
Gaussian plume models
Nuclear safety
Plume dispersion
Radiological protection
Second generation
Standard deviation
Transfer coefficient
Atmospheric movements
Dispersions
Fuels
Gaussian distribution
Industrial poisons
Krypton
Landforms
Nuclear energy
Radiology
Nuclear fuel reprocessing
krypton 85
atmospheric plume
atmospheric pollution
complex terrain
concentration (composition)
dispersion
Gaussian method
krypton
numerical model
radionuclide
article
atmospheric dispersion
comparative study
kernel method
nuclear fuel reprocessing
plume dispersion
prediction
radiation measurement
simulation
Air Movements
Air Pollutants
Radioactive
Atmosphere
Geography
Krypton Radioisotopes
Normal Distribution
Radiation Monitoring
Basse Normandie
France
La Hague
Manche