Johnson, M, Peakall, J, Fairweather, M et al. (3 more authors) (2016) Gas Retention and Release from Nuclear Legacy Waste. In: Annual Waste Management Conference (WM2016): Education & Opportunity in Waste Management. Waste Management (WM) Conference, 06-10 Mar 2016, Phoenix, Arizona, USA. WM Symposia ISBN 9781510826335
Abstract
The retention of gas within corroded magnox sludge waste at Sellafield, UK and secondary reprocessing waste at Hanford, USA has significant economic and safety implications for decommissioning various nuclear legacy buildings, including the magnox swarf storage silos and first generation magnox storage pond. A series of laboratory scale gas retention tests within magnesium hydroxide soft sediments have revealed a 4-51 Pa yield stress range where consolidated beds could retain sufficient gas to become buoyant with respect to a water supernatant. Density inversion could lead to a Rayleigh-Taylor style instability which could result in an upward transfer of radioactive material from the consolidated bed. The applicable yield stress range suggests that such rollover events may occur in weaker sediment than previously hypothesized, based on current understanding of the fluidization and stable channel mechanisms for gas release from weak and very strong sediments respectively. Xray computed tomography images of gas retained by 7 Pa yield stress soft sediment reveal both a stable foam layer at the top of the bed and regions dense with microbubbles which could provide pathways for gas transport through the bed. Extension of these pathways, hidden below the surface of the sediment, to the container walls and the foam layer could represent a novel mechanism for gas release from intermediate strength sediments of <100 Pa yield stress.
Metadata
Item Type: | Proceedings Paper |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2016 by Waste Management Symposia, Inc. This is an author produced version of a paper published in Annual Waste Management Conference (WM2016). |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Institute for Applied Geosciences (IAG) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 25 Feb 2016 10:23 |
Last Modified: | 05 Jan 2017 13:38 |
Status: | Published |
Publisher: | WM Symposia |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:94814 |