title: Environmental releases from fuel cycle facility: part 1: radionuclide resuspension vs. stack releases on ambient airborne uranium and thorium levels.
abstract: Airborne activity levels of uranium and thorium series were measured in the vicinity (1.1 km) of a uranium (UF4) processing plant, located in Malvési, south of France. Regarding its impact on the environment, this facility is characterized by its routine atmospheric releases of uranium and by the emission of radionuclide-labelled particles from a storage pond filled with waste water or that contain dried sludge characterized by traces of plutonium and thorium ((230)Th). This study was performed during a whole year (November 2009-November 2010) and based on weekly aerosol sampling. Thanks to ICP-MS results, it was possible to perform investigations of uranium and thorium decay product concentration in the air. The number of aerosol filters sampled (50) was sufficient to establish a relationship between airborne radionuclide variations and the wind conditions. As expected, the more the time spent in the plume, the higher the ambient levels. The respective contributions of atmospheric releases and resuspension from local soil and waste ponds on ambient dust load and uranium-bearing aerosols were estimated. Two shutdown periods dedicated to facility servicing made it possible to estimate the resuspension contribution and to specify its origin (local or regional) according to the wind direction and remote background concentration. Airborne uranium mainly comes from the emission stack and, to a minor extent (∼20%), from wind resuspension of soil particles from the surrounding fields and areas devoted to waste storage. Moreover, weighed activity levels were clearly higher during operational periods than for shutdown periods.
authors.affiliation: Institute for Radiological Protection and Nuclear Safety (IRSN), BP 3, 13115 St Paul lez Durance Cedex, France. Electronic address: olivier.masson@irsn.fr.
authors.forename: Olivier
authors.initials: O
authors.lastname: Masson
authors.affiliation: Institute for Radiological Protection and Nuclear Safety (IRSN), BP 3, 13115 St Paul lez Durance Cedex, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Pourcelot
authors.affiliation: Institute for Radiological Protection and Nuclear Safety (IRSN), LMRE, Bâtiment 501, Bois des Rames, 91400 Orsay, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Boulet
authors.affiliation: Institute for Radiological Protection and Nuclear Safety (IRSN), LMRE, Bâtiment 501, Bois des Rames, 91400 Orsay, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Cagnat
authors.affiliation: AREVA NC, Usine de Malvési, 11100 Narbonne, France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Videau
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D005602:France; D013058:Mass Spectrometry; D012621:Seasons; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D013910:Thorium / Q000032:analysis*; D014501:Uranium / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*; D014919:Wind
chemical_list: D000396:Air Pollutants, Radioactive; D012990:Soil Pollutants, Radioactive; D014875:Water Pollutants, Radioactive; D014501:Uranium; D013910:Thorium
keywords: Aerosol; Environment; Resuspension; Thorium; UF(4); Uranium