Particulate plutonium released from the Fukushima Daiichi meltdowns

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

doi:10.1016/j.scitotenv.2020.140539

Cited by 37 publications

(22 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In summary, hot particles released via high energy sub-critical incidents acquire their compositions and textures at high temperature within the explosion cloud, and this mode of formation sets the scene for their long-term environmental behaviour 1 . We note that hot particles released following high energy failure of containment in nuclear reactors, such as Chernobyl 17 , 41 , 42 and Fukushima 43 , also show heterogeneous compositions, with U ± Pu associated with Zr and other metals from the reactor cladding 43 – 45 . These particles share a formation via cooling of high temperature melts, however in this case melting occurs in the nuclear fuel rather than in the explosion cloud.…”

Section: Discussionmentioning

confidence: 92%

The nature of Pu-bearing particles from the Maralinga nuclear testing site, Australia

Cook

Etschmann

Ram

et al. 2021

Sci Rep

View full text Add to dashboard Cite

The high-energy release of plutonium (Pu) and uranium (U) during the Maralinga nuclear trials (1955–1963) in Australia, designed to simulate high temperature, non-critical nuclear accidents, resulted in wide dispersion µm-sized, radioactive, Pu–U-bearing ‘hot’ particles that persist in soils. By combining non-destructive, multi-technique synchrotron-based micro-characterization with the first nano-scale imagining of the composition and textures of six Maralinga particles, we find that all particles display intricate physical and chemical make-ups consistent with formation via condensation and cooling of polymetallic melts (immiscible Fe–Al–Pu–U; and Pb ± Pu–U) within the detonation plumes. Plutonium and U are present predominantly in micro- to nano-particulate forms, and most hot particles contain low valence Pu–U–C compounds; these chemically reactive phases are protected by their inclusion in metallic alloys. Plutonium reworking was observed within an oxidised rim in a Pb-rich particle; however overall Pu remained immobile in the studied particles, while small-scale oxidation and mobility of U is widespread. It is notoriously difficult to predict the long-term environmental behaviour of hot particles. Nano-scale characterization of the hot particles suggests that long-term, slow release of Pu from the hot particles may take place via a range of chemical and physical processes, likely contributing to on-going Pu uptake by wildlife at Maralinga.

show abstract

Section: Discussionmentioning

confidence: 92%

The nature of Pu-bearing particles from the Maralinga nuclear testing site, Australia

Cook

Etschmann

Ram

et al. 2021

Sci Rep

View full text Add to dashboard Cite

show abstract

“…On the other hand, the detection of type A CsMPs has been continued up to 2019 and no obvious decreasing trend has been found from annual resuspension frequencies, suggesting its persistence. The CsMPs can also work as the transferring medium of fuel debris, 66 trace uranium, 17,52 strontium, 67 and plutonium 68 into the environment, although they are at very low level, and CsMPs resuspension increases the possibility of unpredictable inhalation. If they are inhaled, they can easily reach the deep respiratory system.…”

Section: Discussionmentioning

confidence: 99%

Atmospheric Resuspension of Insoluble Radioactive Cesium Particles Found in the Difficult-to-Return Area in Fukushima

Tang

Kita

Igarashi

et al. 2021

Preprint

View full text Add to dashboard Cite

The deposition of insoluble radiocesium bearing microparticles (CsMPs), which were released from the Fukushima Daiichi Nuclear Power Plant (F1NPP) accident in March 2011, has resulted in the widespread contamination of eastern Japan. Obviously, these deposited insoluble CsMPs may become the secondary contamination sources by atmospheric migration or other environmental transferring process, however, the understanding of the transport mechanism remains non-elucidation, and the relevant evidence has not been directly provided. This study, for the first time, provides the direct evidence for the resuspension of these insoluble CsMPs to the atmosphere from 1) proximity of 137Cs radioactivity and resemblance of the morphology and the elemental compositions of CsMPs in the samples of soil and aerosol derived from the same sampling site, 2) the special characteristics of the resuspended CsMPs of which the ratios of Na/Si, K/Si and/or Cs/Si were smaller than those from the initially released CsMPs collected at either long distance or near F1NPP, which can be ascribed to the slowly natural corrosion of CsMPs by the loss of the small amount of soluble contents in CsMPs and 3) high CsMPs concentration of 10 granules/gram in the surface soil of our sampling site and the observed resuspension of surface soil dust at wind gust speed higher than 4 m s-1. Specifically, fifteen single CsMPs were successfully isolated from the aerosol filters collected by unmanned high-volume air samplers at a severely polluted area in Fukushima Prefecture, about 25 km away from F1NPP, from January 2015 to September 2019. The mean diameter of these CsMPs was 1.8 ± 0.5 μm, and the average 137Cs radioactivity was 0.35 ± 0.23 Bq/granule. The contribution rate of the resuspended CsMPs to the atmospheric radiocesium was estimated from the ratio of 137Cs radioactivity of a single CsMP to that of the aerosol filter to be of 23.9 ± 15.3%. There has been no considerable decreasing trend in the annual CsMP resuspension frequency.

show abstract

“…Although U occurrence was successfully characterized in the above studies, Pu occurrence as a particulate form remained unknown. Recently [47], reported, for the first time, the Pu occurrence closely related to U embedded in CsMPs. The isotope ratios of 240 Pu/ 239 Pu and 242 Pu/ 239 Pu were determined to be 0.331-0.349 and 0.0622-0.0668, respectively, by using a SIMS (SHRIMP-II) (Fig.…”

Section: Isotopic and Physio-chemical Properties Of Debris Fragments In Fukushimamentioning

confidence: 99%

“…The isotope ratios of 240 Pu/ 239 Pu and 242 Pu/ 239 Pu were determined to be 0.331-0.349 and 0.0622-0.0668, respectively, by using a SIMS (SHRIMP-II) (Fig. 6) [47], which is comparable to the average ratio calculated using ORIGEN [22]. Additionally, using synchrotron-based μXRF and μXAS analysis of one of the CsMPs the U distribution was successfully mapped in the CsMP showing that the speciation was equivalent to that of UO 2 (Figure 7) [47].…”

Section: Isotopic and Physio-chemical Properties Of Debris Fragments In Fukushimamentioning

confidence: 99%

Ten years after the NPP accident at Fukushima : review on fuel debris behavior in contact with water

Grambow

Nitta

Shibata

et al. 2021

Journal of Nuclear Science and Technology

Self Cite

View full text Add to dashboard Cite

Following the NPP accident, several hundred tons of heat-generating corium and fuel debris have been cooled permanently by millions of m 3 of flowing. Knowledge on the interaction with water is crucial for any decommissioning planning.Starting from knowledge on the evolutions of the accident in the three reactor cores and associated fuel debris formations and some additional isotopic and physio-chemical information on debris fragments collected in Fukushima soils, we review the temporal evolution of the chemistry and leached radionuclide contents of the cooling water, comparing measured concentration ratios of the actinides and fission products in the water to reported results of laboratory leaching studies with either spent nuclear fuel or simulated fuel debris.As for spent fuel leaching, the fractions of inventories of 134,137 Cs in the cooling water are orders of magnitude larger than that of the actinides. After more than 10 years of fuel debris/ water contact, 137 Cs release rates have decreased by about a factor of 100. The total release of actinides from the fuel debris is orders of magnitude lower than that of 134,137 Cs or of 90 Sr. This high stability makes direct disposal of fuel debris in suitable containers after decommissioning a viable option.

show abstract

Particulate plutonium released from the Fukushima Daiichi meltdowns

Cited by 37 publications

References 39 publications

The nature of Pu-bearing particles from the Maralinga nuclear testing site, Australia

The nature of Pu-bearing particles from the Maralinga nuclear testing site, Australia

Atmospheric Resuspension of Insoluble Radioactive Cesium Particles Found in the Difficult-to-Return Area in Fukushima

Ten years after the NPP accident at Fukushima : review on fuel debris behavior in contact with water

Contact Info

Product

Resources

About