Microstructure changes and thermal conductivity reduction in UO2 following 3.9 MeV He2+ ion irradiation

Janne Pakarinen, Marat Khafizov, Lingfeng He, Chris Wetteland, Jian Gan, Andrew T. Nelson, David H. Hurley, Anter El-Azab, Todd R. Allen

    Research outputpeer-review

    34 Scopus citations

    Abstract

    The microstructural changes and associated effects on thermal conductivity were examined in UO2 after irradiation using 3.9 MeV He2+ ions. Lattice expansion of UO2 was observed in X-ray diffraction after ion irradiation up to 5 × 1016 He2+/cm 2 at low-temperature (<200 °C). Transmission electron microscopy (TEM) showed homogenous irradiation damage across an 8 μm thick plateau region, which consisted of small dislocation loops accompanied by dislocation segments. Dome-shaped blisters were observed at the peak damage region (depth around 8.5 μm) in the sample subjected to 5 × 10 16 He2+/cm2, the highest fluence reached, while similar features were not detected at 9 × 1015 He 2+/cm2. Laser-based thermo-reflectance measurements showed that the thermal conductivity for the irradiated layer decreased about 55% for the high fluence sample and 35% for the low fluence sample as compared to an un-irradiated reference sample. Detailed analysis for the thermal conductivity indicated that the conductivity reduction was caused by the irradiation induced point defects.

    Original languageEnglish
    Pages (from-to)283-289
    Number of pages7
    JournalJournal of Nuclear Materials
    Volume454
    Issue number1-3
    DOIs
    StatePublished - Nov 2014

    ASJC Scopus subject areas

    • Nuclear and High Energy Physics
    • General Materials Science
    • Nuclear Energy and Engineering

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