Radiation-induced decomposition of U(VI) alteration phases of UO 2

Satoshi Utsunomiya, Rodney C. Ewing

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Citations (Scopus)

Abstract

U6+-phases are common alteration products of spent nuclear fuel under oxidizing conditions, and they may potentially incorporate actinides, such as long-lived 239Pu and 237Np, delaying their transport to the biosphere. In order to evaluate the ballistic 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 Kr 2+) for six different structures of U6+-phases: uranophane, kasolite, boltwoodite, saleeite, carnotite, and liebigite. The target uranyl-minerals were characterized by powder X-ray diffraction and identification confirmed by SAED (selected area electron diffraction) in TEM (transmission electron microscopy). The TEM observation revealed no initial contamination of uraninite in these U6+ phases. All of the samples were irradiated with in situ TEM observation using 1.0 MeV Kr2+ in the IVEM (intermediate-voltage electron microscope) at the IVEM-Tandem Facility of Argonne National Laboratory. The ion flux was 6.3 × 1011 ions/cm2/sec. The specimen temperatures during irradiation were 298 and 673 K, respectively. The Kr2+-irradiation decomposed the U 6+-phases to nanocrystals of UO2 at doses as low as 0.006 dpa. The cumulative doses for the pure U6+-phases, e.g., uranophane, at 0.1 and 1 million years (m.y.) are calculated to be 0.009 and 0.09 dpa using SRIM2003. However, with the incorporation of 1 wt.% 239Pu, the calculated doses reach 0.27 and ∼1.00 dpa in ten thousand and one hundred thousand years, respectively. Under oxidizing conditions, multiple cycles of radiation-induced decomposition to UO2 followed by alteration to U6+-phases should be further investigated to determine the fate of trace elements that may have been incorporated in the U6+-phases.

Original languageEnglish
Title of host publication29th International Symposium on the Scientific Basis for Nuclear Waste Management XXIX
Pages465-472
Number of pages8
Publication statusPublished - Jul 24 2006
Externally publishedYes
Event29th International Symposium on the Scientific Basis for Nuclear Waste Management XXIX - Ghent, Belgium
Duration: Sep 12 2005Sep 16 2005

Publication series

NameMaterials Research Society Symposium Proceedings
Volume932
ISSN (Print)0272-9172

Other

Other29th International Symposium on the Scientific Basis for Nuclear Waste Management XXIX
CountryBelgium
CityGhent
Period9/12/059/16/05

Fingerprint

Irradiation
Transmission electron microscopy
Decomposition
decomposition
Radiation
dosage
transmission electron microscopy
irradiation
Electron microscopes
radiation
electron microscopes
Actinoid Series Elements
Ions
biosphere
spent fuels
nuclear fuels
Actinides
Spent fuels
Trace Elements
Nuclear fuels

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Utsunomiya, S., & Ewing, R. C. (2006). Radiation-induced decomposition of U(VI) alteration phases of UO 2. In 29th International Symposium on the Scientific Basis for Nuclear Waste Management XXIX (pp. 465-472). (Materials Research Society Symposium Proceedings; Vol. 932).

Radiation-induced decomposition of U(VI) alteration phases of UO 2. / Utsunomiya, Satoshi; Ewing, Rodney C.

29th International Symposium on the Scientific Basis for Nuclear Waste Management XXIX. 2006. p. 465-472 (Materials Research Society Symposium Proceedings; Vol. 932).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Utsunomiya, S & Ewing, RC 2006, Radiation-induced decomposition of U(VI) alteration phases of UO 2. in 29th International Symposium on the Scientific Basis for Nuclear Waste Management XXIX. Materials Research Society Symposium Proceedings, vol. 932, pp. 465-472, 29th International Symposium on the Scientific Basis for Nuclear Waste Management XXIX, Ghent, Belgium, 9/12/05.
Utsunomiya S, Ewing RC. Radiation-induced decomposition of U(VI) alteration phases of UO 2. In 29th International Symposium on the Scientific Basis for Nuclear Waste Management XXIX. 2006. p. 465-472. (Materials Research Society Symposium Proceedings).
Utsunomiya, Satoshi ; Ewing, Rodney C. / Radiation-induced decomposition of U(VI) alteration phases of UO 2. 29th International Symposium on the Scientific Basis for Nuclear Waste Management XXIX. 2006. pp. 465-472 (Materials Research Society Symposium Proceedings).
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