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

JOURNAL OF NUCLEAR MATERIALS

卷:509

Article

Sutherland-Harper, Sophie¹  Pearce, Carolyn^1,2  Campbell, Catherine³  Carrott, Mike³  Colledge, Hannah³  Gregson, Colin³  Hobbs, Jeff⁴  Livens, Francis¹  Kaltsoyannis, Nikolas¹  Orr, Robin³  Sarsfield, Mark³  Sims, Howard³  Steele, Helen⁴  Vatter, Ian³  Walton, Louise³  Webb, Kevin³  Taylor, Robin³ 

[1] Univ Manchester, Sch Chem, Manchester M13 9PL, Lancs, England

[2] Pacific Northwest Natl Lab, POB 999, Richland, WA 99352 USA

[3] Natl Nucl Lab, Cent Lab, Seascale CA20 1PG, England

[4] Sellafield Ltd, Sellafield CA20 1PG, Seascale, England

关键词: Plutonium dioxide;    Hydrogen chloride;    Thermal treatment;    Desorption;    Stabilisation;   

DOI  :  10.1016/j.jnucmat.2018.07.031

来源: Elsevier

【 摘 要 】

To mimic the reactions that have occurred between plutonium dioxide (PuO2) and degraded polyvinyl chloride during prolonged storage, batches of PuO(2 )powders with varying specific surface area (4-38 m(2) 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 degrees 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. (C) 2018 Elsevier B.V. All rights reserved.

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