title: Post-Accident Sporadic Releases of Airborne Radionuclides from the Fukushima Daiichi Nuclear Power Plant Site.
abstract: The Fukushima nuclear accident (March 11, 2011) caused the widespread contamination of Japan by direct deposition of airborne radionuclides. Analysis of weekly air filters has revealed sporadic releases of radionuclides long after the Fukushima Daiichi reactors were stabilized. One major discharge was observed in August 2013 in monitoring stations north of the Fukushima Daiichi nuclear power plant (FDNPP). During this event, an air monitoring station in this previously scarcely contaminated area suddenly reported (137)Cs activity levels that were 30-fold above the background. Together with atmospheric dispersion and deposition simulation, radionuclide analysis in soil indicated that debris removal operations conducted on the FDNPP site on August 19, 2013 are likely to be responsible for this late release of radionuclides. One soil sample in the center of the simulated plume exhibited a high (90)Sr contamination (78 ± 8 Bq kg(-1)) as well as a high (90)Sr/(137)Cs ratio (0.04); both phenomena have usually been observed only in very close vicinity around the FDNPP. We estimate that through the resuspension of highly contaminated particles in the course of these earthmoving operations, gross (137)Cs activity of ca. 2.8 × 10(11) Bq has been released.
authors.affiliation: Colorado State University , Environmental and Radiological Health Sciences, Fort Collins, Colorado 80523, United States.|Leibniz Universität Hannover , Institute of Radioecology and Radiation Protection, D-30419 Hannover, Germany.|Institute of Environmental Radioactivity, Fukushima University , Fukushima 960-1296, Japan.
authors.forename: Georg
authors.initials: G
authors.lastname: Steinhauser
authors.affiliation: Research Division of Atmospheric and Hydrospheric Disasters, Disaster Prevention Research Institute, Kyoto University , Uji 6110011, Japan.
authors.forename: Tamon
authors.initials: T
authors.lastname: Niisoe
authors.affiliation: Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine , Kyoto 6068501, Japan.
authors.forename: Kouji H
authors.initials: KH
authors.lastname: Harada
authors.affiliation: Graduate School of Arts and Sciences, The University of Tokyo , Meguro-ku, Tokyo 153-8902, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shozugawa
authors.affiliation: Leibniz Universität Hannover , Institute of Radioecology and Radiation Protection, D-30419 Hannover, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Schneider
authors.affiliation: Laboratory of Ion Beam Physics, ETH Zürich , CH-8093 Zürich, Switzerland.
authors.forename: Hans-Arno
authors.initials: HA
authors.lastname: Synal
authors.affiliation: Leibniz Universität Hannover , Institute of Radioecology and Radiation Protection, D-30419 Hannover, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Walther
authors.affiliation: Laboratory of Ion Beam Physics, ETH Zürich , CH-8093 Zürich, Switzerland.
authors.forename: Marcus
authors.initials: M
authors.lastname: Christl
authors.affiliation: Institute of Environmental Radioactivity, Fukushima University , Fukushima 960-1296, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Nanba
authors.affiliation: Research Division of Atmospheric and Hydrospheric Disasters, Disaster Prevention Research Institute, Kyoto University , Uji 6110011, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Ishikawa
authors.affiliation: Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine , Kyoto 6068501, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Koizumi
mesh_terms: D061808:Air Filters; D000396:Air Pollutants, Radioactive / Q000032:analysis*; D002588:Cesium Radioisotopes / Q000032:analysis*; D062406:Fukushima Nuclear Accident; D007564:Japan; D055848:Nuclear Power Plants; D011834:Radiation Monitoring / Q000295:instrumentation / Q000379:methods
chemical_list: D000396:Air Pollutants, Radioactive; D002588:Cesium Radioisotopes