Isotopic signature and nano-texture of cesium-rich micro-particles: Release of uranium and fission products from the Fukushima Daiichi Nuclear Power Plant
Journal
Scientific Reports
Journal Volume
7
Journal Issue
1
ISSN
2045-2322
Date Issued
2017-07-14
Author(s)
Imoto, Junpei
Ochiai, Asumi
Furuki, Genki
Suetake, Mizuki
Ikehara, Ryohei
Horie, Kenji
Takehara, Mami
Yamasaki, Shinya
Nanba, Kenji
Ohnuki, Toshihiko
Law, Gareth T. W.
Grambow, Bernd
Ewing, Rodney C.
Abstract
Highly radioactive cesium-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) provide nano-scale chemical fingerprints of the 2011 tragedy. U, Cs, Ba, Rb, K, and Ca isotopic ratios were determined on three CsMPs (3.79-780 Bq) collected within ~10 km from the FDNPP to determine the CsMPs' origin and mechanism of formation. Apart from crystalline Fe-pollucite, CsFeSi2O6 · nH2O, CsMPs are comprised mainly of Zn-Fe-oxide nanoparticles in a SiO2 glass matrix (up to ~30 wt% of Cs and ~1 wt% of U mainly associated with Zn-Fe-oxide). The 235U/238U values in two CsMPs: 0.030 (±0.005) and 0.029 (±0.003), are consistent with that of enriched nuclear fuel. The values are higher than the average burnup estimated by the ORIGEN code and lower than non-irradiated fuel, suggesting non-uniform volatilization of U from melted fuels with different levels of burnup, followed by sorption onto Zn-Fe-oxides. The nano-scale texture and isotopic analyses provide a partial record of the chemical reactions that occurred in the fuel during meltdown. Also, the CsMPs were an important medium of transport for the released radionuclides in a respirable form.
Subjects
Cesium Radioisotopes
Fukushima Nuclear Accident
Geography
Glass
Japan
Nuclear Power Plants
Radiation Monitoring
Radioactive Pollutants
Silicon Dioxide
Uranium
cesium
glass
silicon dioxide
uranium
Uranium-235
Uranium-238
analysis
Fukushima nuclear accident
geography
nuclear power plant
pollutant
procedures
radiation monitoring
Publisher
Springer Science and Business Media LLC
Type
journal article