Structural and compositional characteristics of Fukushima release particulate material from Units 1 and 3 elucidates release mechanisms, accident chronology and future decommissioning strategy

DOI: 10.1038/s41598-020-79169-2

Authors: Peter Martin (University of Bristol) , Christopher P. Jones (University of Bristol) , Stuart Bartlett (Diamond Light Source) , Konstantin Ignatyev (Diamond Light Source) , Dave Megson-smith (University of Bristol) , Yukihiko Sato (Japan Atomic Energy Agency (JAEA)) , Silvia Cipiccia (Diamond Light Source) , Darren J. Batey (Diamond Light Source) , Christoph Rau (Diamond Light Source) , Keisuke Sueki (University of Tsukuba) , Tatsuya Ishii (University of Tsukuba) , Junya Igarashi (Osaka University) , Kazuhiko Ninomiya (Osaka University) , Atsushi Shinohara (Osaka University) , Alison Rust (University of Bristol) , Thomas B. Scott (University of Bristol)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Scientific Reports , VOL 10

State: Published (Approved)
Published: December 2020
Diamond Proposal Number(s): 24769 , 19881

Abstract: The structural form and elemental distribution of material originating from different Fukushima Daiichi Nuclear Power Plant reactors (Units 1 and 3) is hereby examined to elucidate their contrasting release dynamics and the current in-reactor conditions to influence future decommissioning challenges. Complimentary computed X-ray absorption tomography and X-ray fluorescence data show that the two suites of Si-based material sourced from the different reactor Units have contrasting internal structure and compositional distribution. The known event and condition chronology correlate with the observed internal and external structures of the particulates examined, which suggest that Unit 1 ejecta material sustained a greater degree of melting than that likely derived from reactor Unit 3. In particular, we attribute the near-spherical shape of Unit 1 ejecta and their internal voids to there being sufficient time for surface tension to round these objects before the hot (and so relatively low viscosity) silicate melt cooled to form glass. In contrast, a more complex internal form associated with the sub-mm particulates invoked to originate from Unit 3 suggest a lower peak temperature, over a longer duration. Using volcanic analogues, we consider the structural form of this material and how it relates to its environmental particulate stability and the bulk removal of residual materials from the damaged reactors. We conclude that the brittle and angular Unit 3 particulate are more susceptible to further fragmentation and particulate generation hazard than the round, higher-strength, more homogenous Unit 1 material.

Journal Keywords: Energy science and technology; Environmental impact; Environmental sciences; Materials science; Physics

Subject Areas: Physics, Materials, Environment


Instruments: I13-1-Coherence , I18-Microfocus Spectroscopy

Documents:
s41598-020-79169-2.pdf