Particulate plutonium released from the Fukushima Daiichi meltdowns

Eitaro Kurihara; Masato Takehara; Mizuki Suetake; Ryohei Ikehara; Tatsuki Komiya; Kazuya Morooka; Ryu Takami; Shinya Yamasaki; Toshihiko Ohnuki; Kenji Horie; Mami Takehara; Gareth T W Law; William Bower; J Frederick W Mosselmans; Peter Warnicke; Bernd Grambow; Rodney C Ewing; Satoshi Utsunomiya

doi:10.1016/j.scitotenv.2020.140539

Particulate plutonium released from the Fukushima Daiichi meltdowns

Sci Total Environ. 2020 Nov 15:743:140539. doi: 10.1016/j.scitotenv.2020.140539. Epub 2020 Jul 8.

Authors

Eitaro Kurihara¹, Masato Takehara¹, Mizuki Suetake¹, Ryohei Ikehara¹, Tatsuki Komiya¹, Kazuya Morooka¹, Ryu Takami¹, Shinya Yamasaki², Toshihiko Ohnuki³, Kenji Horie⁴, Mami Takehara⁵, Gareth T W Law⁶, William Bower⁶, J Frederick W Mosselmans⁷, Peter Warnicke⁸, Bernd Grambow⁹, Rodney C Ewing¹⁰, Satoshi Utsunomiya¹¹

Affiliations

¹ Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
² Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan.
³ Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
⁴ National Institute of Polar Research, 10-3, Midori-cho, Tachikawa-shi, Tokyo 190-8518, Japan; Department of Polar Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193, Japan.
⁵ National Institute of Polar Research, 10-3, Midori-cho, Tachikawa-shi, Tokyo 190-8518, Japan.
⁶ Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki 00014, Finland.
⁷ Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK.
⁸ Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland.
⁹ SUBATECH, IMT Atlantique, CNRS-IN2P3, The University of Nantes, Nantes 44307, France.
¹⁰ Department of Geological Sciences and Center for International Security and Cooperation, Stanford University, Stanford, CA 94305-2115, USA.
¹¹ Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan. Electronic address: utsunomiya.satoshi.998@m.kyushu-u.ac.jp.

PMID: 32663681
DOI: 10.1016/j.scitotenv.2020.140539

Abstract

Traces of Pu have been detected in material released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March of 2011; however, to date the physical and chemical form of the Pu have remained unknown. Here we report the discovery of particulate Pu associated with cesium-rich microparticles (CsMPs) that formed in and were released from the reactors during the FDNPP meltdowns. The Cs-pollucite-based CsMP contained discrete U(IV)O₂ nanoparticles, <~10 nm, one of which is enriched in Pu adjacent to fragments of Zr-cladding. The isotope ratios, ²³⁵U/²³⁸U, ²⁴⁰Pu/²³⁹Pu, and ²⁴²Pu/²³⁹Pu, of the CsMPs were determined to be ~0.0193, ~0.347, and ~0.065, respectively, which are consistent with the calculated isotopic ratios of irradiated-fuel fragments. Thus, considering the regional distribution of CsMPs, the long-distance dispersion of Pu from FNDPP is attributed to the transport by CsMPs that have incorporated nanoscale fuel fragments prior to their dispersion up to 230 km away from the Fukushima Daiichi reactor site.

Keywords: Cs-rich microparticle; Fuel fragment; Fukushima Daiichi; Plutonium; Uranium.

MeSH terms

Cesium Radioisotopes / analysis
Fukushima Nuclear Accident*
Japan
Nuclear Power Plants
Plutonium / analysis*
Radiation Monitoring*

Substances

Cesium Radioisotopes
Plutonium