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Communication Dans Un Congrès Année : 2020

Radiation Effects in UO2 and Other Oddities of the Unstable Valences

Résumé

Since the stable valences of U in its oxides are IV, V, and VI, the formation of reduced species in UO2 is problematic. This is demonstrated in XAFS measurements of UO2 irradiated with protons and helium nuclei. The addition of O occurs by clustering that results in UO2-U4O9 phase separation, facilitated by the virtually identical U sublattices of these two species. Ion beam irradiation that displaces O ions could give the same behavior, but whereas disorder is observed the signatures of U4O9 are not. This is most likely because, whereas the O-enriched regions with mixed valence U(IV,V) would be stable, the U(III) formed in the O-depleted regions is not. A different mechanism is activated. This could also be important in the chemistry of the fuel and the O potential formed in response to the temperature gradient.
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Dates et versions

hal-03194980 , version 1 (09-04-2021)

Identifiants

  • HAL Id : hal-03194980 , version 1

Citer

Steven D. Conradson, Janne Pakarinen, Gianguido Baldinozzi. Radiation Effects in UO2 and Other Oddities of the Unstable Valences. Defects, Order and Disorder in Structural and Functional Fluorite-Related Compounds (Symp CT05), Materials Research Society (MRS), Nov 2020, Boston (Virtual), United States. ⟨hal-03194980⟩
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