Radiation-induced decomposition of U(VI) phases to nanocrystals of UO2

Satoshi Utsunomiya, Rodney C. Ewing, Lu Min Wang

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

U6+-phases are common alteration products, under oxidizing conditions, of uraninite and the UO2 in spent nuclear fuel. These U6+-phases are subjected to a radiation field caused by the α-decay of U, or in the case of spent nuclear fuel, incorporated actinides, such as 239Pu and 237Np. In order to evaluate the effects of α-decay events on the stability of the U6+-phases, we report, for the first time, the results of ion beam irradiations (1.0 MeV Kr2+) of U6+-phases. The heavy-particle irradiations are used to simulate the ballistic interactions of the recoil-nucleus of an α-decay event with the surrounding structure. The Kr2+ -irradiation decomposed the U6+-phases to UO2 nanocrystals at doses as low as 0.006 displacements per atom (dpa). U6+-phases accumulate substantial radiation doses (∼1.0 displacement per atom) within 100,000 yr if the concentration of incorporated 239Pu is as high as 1 wt.%. Similar nanocrystals of UO2 were observed in samples from the natural fission reactors at Oklo, Gabon. Multiple cycles of radiation-induced decomposition to UO2 followed by alteration to U6+-phases provide a mechanism for the remobilization of incorporated radionuclides.

Original languageEnglish
Pages (from-to)521-528
Number of pages8
JournalEarth and Planetary Science Letters
Volume240
Issue number2
DOIs
Publication statusPublished - Dec 1 2005

Fingerprint

Nanocrystals
spent fuels
nanocrystals
irradiation
nuclear fuels
Spent fuels
Nuclear fuels
Irradiation
decomposition
Decomposition
Radiation
Gabon
decay
radiation
Actinoid Series Elements
dosage
Atoms
uraninite
actinide
remobilization

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Radiation-induced decomposition of U(VI) phases to nanocrystals of UO2. / Utsunomiya, Satoshi; Ewing, Rodney C.; Wang, Lu Min.

In: Earth and Planetary Science Letters, Vol. 240, No. 2, 01.12.2005, p. 521-528.

Research output: Contribution to journalArticle

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