New insight into self-irradiation effects on local and long-range structure of uranium-americium mixed oxides (through XAS and XRD)

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • Florent Lebreton
  • Philippe M. Martin
  • Denis Horlait
  • Ph.D. Rene Bes

  • Andreas C. Scheinost
  • Andre Rossberg
  • Thibaud Delahaye
  • Philippe Blanchart

Research units

  • CEA
  • GEMH, ENSCI
  • Helmholtz-Zentrum Dresden-Rossendorf

Abstract

Uranium-americium mixed oxides could be used as transmutation targets to lower Am inventory in spent nuclear fuels. Due to 241Am activity, these materials are subjected to α-selfirradiation which provokes crystallographic disorder. Previous studies on U-Am mixed oxides gave first insight into α-radiation tolerance of these compounds, but have never been carried out for more than a year, whereas these compounds might be stored up to a few years between fabrication and irradiation. In this work, we study effects of self-irradiation on the structure of U1-xAmxO2±δ solid solutions (x = 0.15 and 0.20) aged 3 to 4 years. Especially, Xray diffraction and X-ray absorption spectroscopy are combined to observe these effects from both long-range and local perspectives. Results show that the fluorite-type structure of U-Am mixed oxides withstands 241Am α-irradiation without major damage. Despite the increase of interatomic distances and crystallographic disorder observed during the first months of storage, the present results show that a steady state is then reached. Thus, no detrimental factors have been identified in this study in terms of structural damage for several-year storage of U1-xAmxO2±δ pellets before irradiation. Furthermore, comparison between long-range and local evolution suggests that α-self-irradiationinduced defects are mainly located in low-ordered domains. Based on literature data and present results, the steady state appears related to the equilibrium between radioinduced defect formation and material self-healing.

Details

Original languageEnglish
Pages (from-to)9531-9540
Number of pages10
JournalInorganic Chemistry
Volume53
Issue number18
Publication statusPublished - 15 Sep 2014
MoE publication typeA1 Journal article-refereed

ID: 27629847