title: Fission product activity ratios measured at trace level over France during the Fukushima accident.
abstract: The nuclear accident of Fukushima Dai-ichi (Japan) which occurred after the tsunami that impacted the northeast coasts of Japan on March 11th, 2011 led to significant releases of radionuclides into the atmosphere and resulted in the detection of those radionuclides at a global scale. In order to track airborne radionuclides from the damaged reactors and to survey their potential impact on the French territory, the French Institute of Radiation Protection and Nuclear Safety (Institut de Radioprotection et de Sureté Nucléaire IRSN) set up an enhanced surveillance system to give quick results as needed and later give quality trace level measurements. Radionuclides usually measured at trace levels such as (137)Cs and in a very sporadic way (131)I were reported. Radionuclides that we had never measured in air since the Chernobyl accident: (134)Cs, (136)Cs, the mother/daughter pairs (129m)Te-(129)Te and (132)Te-(132)I, and (140)La (from the mother-daughter pair (140)Ba- (140)La) were also reported. Except the (131)I/(137)Cs ratio, activity concentration ratios were constant. These ratios could be used to help source term assessment, or as data for transfer studies realized after the passage of contaminated air masses, typically using the (134)Cs/(137)Cs ratio.
authors.affiliation: Laboratoire de Mesure de la Radioactivité dans l'Environnement, Institut de Radioprotection et de Sûreté Nucléaire, PRP-ENV/STEME/LMRE, Bois des Rames, Bât 501, 91400 Orsay, France. Electronic address: anne.de-vismes@irsn.fr.
authors.forename: A
authors.initials: A
authors.lastname: de Vismes Ott
authors.forename: R
authors.initials: R
authors.lastname: Gurriaran
authors.forename: X
authors.initials: X
authors.lastname: Cagnat
authors.forename: O
authors.initials: O
authors.lastname: Masson
mesh_terms: D000336:Aerosols; D000396:Air Pollutants, Radioactive / Q000032:analysis*; D005602:France; D062406:Fukushima Nuclear Accident; D009680:Nuclear Fission; D011834:Radiation Monitoring; D011868:Radioisotopes / Q000032:analysis*
chemical_list: D000336:Aerosols; D000396:Air Pollutants, Radioactive; D011868:Radioisotopes
keywords: Aerosol filters; Fission products; Fukushima Dai-ichi accident; Low-level gamma-ray spectrometry