Analysis of External Surface Irregularities on Fukushima-Derived Fallout Particles

Peter George Martin,Ian Griffiths,Thomas Scott,David Richards,Yukihiko Satou

doi:10.3389/fenrg.2017.00025

Abstract

Three large high radioactivity particulate fragments, each several hundred micron in diameter, have been recovered from the region immediately surrounding the Fukushima Daiichi Nuclear Power Plant. Through the application of high-resolution electron and ion-beam methods, this work has sought to investigate the structure and composition of this fibrous surface morphology. By evaluating this, a potential material source can be determined, alongside important information relating to the conditions / events at the time of the reactor explosions and catastrophic release of radioactive materials. The results of this study show that the fibrous features associated with these large radiocesium-containing particles share a common elemental composition. With respect to the surrounding particle, the fibres are enriched in Si, Cl and Fe, whilst depleted in both Zn and Al. Based on composition, these fibres are ascribed to thermal insulating material used within the plant, which was sufficiently heated during the Loss of coolant incident (LOCI) at the plant to be incorporated into the molten ejecta material that rapidly solidified upon quenching in air. Elemental analysis of these fibres does not reveal any evidence of leaching or the presence of actinide materials.

Highlights

Resulting from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident that occurred during March 2011, a considerable volume of radioactive fallout was deposited onto mainland Japan as well as out into the neighboring Pacific Ocean (Chino et al, 2011; Kawamura et al, 2011)
Analysis of the particulate material presented in this study has allowed for a far greater understanding of the likely source of these submillimeter radioactive particles found in the environment surrounding the FDNPP
The analysis provides greater insight into the events that occurred during March 2011 as the reactor facility experienced multiple different loss of coolant incidents with ensuing reactor building explosions

Summary

Introduction

Resulting from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident that occurred during March 2011, a considerable volume of radioactive fallout was deposited onto mainland Japan as well as out into the neighboring Pacific Ocean (Chino et al, 2011; Kawamura et al, 2011). A similar elemental enrichment for the fibrous component of the material is apparent for Al, where a clear disparity is observed between the bulk particle and the associated surface fiber.

Results

Conclusion