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This content will become publicly available on July 17, 2019

Title: Characterisation and heat treatment of chloride-contaminated and humidified PuO 2 samples

To mimic the reactions that have occurred between plutonium dioxide (PuO 2) 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 °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 TiO 2. This indicates that it is interactions between hydrogen chloride/chloride and water/hydroxyl species on the PuO 2 surface that are key to understanding the behaviour of these materials when heated in a furnace. Furthermore, these data will inform the design of a future thermal stabilisation process for chloride-contaminated PuO 2.
Authors:
 [1] ; ORCiD logo [2] ;  [3] ;  [3] ;  [3] ;  [3] ; ORCiD logo [4] ;  [1] ; ORCiD logo [1] ;  [3] ;  [3] ;  [3] ;  [4] ;  [3] ;  [3] ;  [3] ; ORCiD logo [3]
  1. Univ. of Manchester, Manchester (United Kingdom)
  2. Univ. of Manchester, Manchester (United Kingdom); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  3. National Nuclear Lab., Seascale (United Kingdom)
  4. Sellafield Ltd., Seascale (United Kingdom)
Publication Date:
Grant/Contract Number:
AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Journal of Nuclear Materials
Additional Journal Information:
Journal Volume: 509; Journal Issue: C; Journal ID: ISSN 0022-3115
Publisher:
Elsevier
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; Plutonium dioxide; Hydrogen chloride; Thermal treatment; Desorption; Stabilisation
OSTI Identifier:
1461644