Combined Effects of Radiation Damage and He Accumulation on Bubble Nucleation in Gd2Ti2O7

Caitlin Taylor, Maulik Patel, Yanwen Zhang, Miguel Crespillo, Juan Wen, Haizhou Xue, Yongqiang Wang, William Weber, Jeffery Aguiar

Research output: Contribution to journalArticlepeer-review

17 Scopus Citations

Abstract

Pyrochlores have long been considered as host phases for long-term immobilization of radioactive waste nuclides that would undergo ..alpha..-decay for hundreds of thousands of years. This work utilizes ion-beam irradiations to examine the combined effects of radiation damage and He accumulation on bubble formation in Gd2Ti2O7 over relevant waste-form timescales. Helium bubbles are not observed in pre-damaged Gd2Ti2O7 implanted with 2 x 1016 He/cm2, even after post-implantation irradiations with 7 MeV Au3+ at 300, 500, and 700 K. However, He bubbles with average diameters of 1.5 nm and 2.1 nm are observed in pre-damaged (amorphous) Gd2Ti2O7 and pristine Gd2Ti2O7, respectively, after implantation of 2 x 1017 He/cm2. The critical He concentration for bubble nucleation in Gd2Ti2O7 is estimated to be 6 at.% He.
Original languageAmerican English
Pages (from-to)542-547
Number of pages6
JournalJournal of Nuclear Materials
Volume479
DOIs
StatePublished - 2016

NREL Publication Number

  • NREL/JA-5K00-66933

Keywords

  • helium bubble
  • nuclear waste
  • pyrochlore
  • radiation damage

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