Characterisation and heat treatment of chloride-contaminated and humidified PuO2 samples

Sophie Sutherland-harper, Carolyn Pearce, Catherine Campbell, Mike Carrott, Hannah Colledge, Colin Gregson, Jeff Hobbs, Francis Livens, Nikolas Kaltsoyannis, Robin Orr, Mark Sarsfield, Howard Sims, Helen Steele, Ian Vatter, Louise Walton, Kevin Webb, Robin Taylor

    Research output: Contribution to journalArticlepeer-review


    To mimic the reactions that have occurred between plutonium dioxide (PuO2) and degraded polyvinyl chloride during prolonged storage, batches of PuO2 powders with varying specific surface area (4–38 m2 g−1) were exposed to dry hydrogen chloride gas forming a surface-sorbed exchangeable chloride species that was readily leached by dilute caustic solution. One batch was also humidified under a 95% relative humidity atmosphere. Heat treatment at temperatures between 100 and 950 °C steadily reduced the leachable chloride content at least when the initial leachable chloride surface coverage was calculated to be > 0.5 monolayer (ML). Variations between samples are attributed to differences in surface area as well as production route and period of interim storage in air or humidified atmospheres. The data are consistent with surface species and reactions proposed in the literature for HCl adsorption on to TiO2. This indicates that it is interactions between hydrogen chloride/chloride and water/hydroxyl species on the PuO2 surface that are key to understanding the behaviour of these materials when heated in a furnace. These data will inform the design of a future thermal stabilisation process for chloride-contaminated PuO2.
    Original languageEnglish
    Pages (from-to)654-666
    Number of pages12
    JournalJournal of Nuclear Materials
    Early online date17 Jul 2018
    Publication statusPublished - Oct 2018


    • Plutonium dioxide
    • Hydrogen chloride
    • Thermal treatment
    • Desorption
    • Stabilisation


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