Collier, NC, Heyes, DW, Butcher, EJ et al. (10 more authors) (2019) Gaseous carbonation of cementitious backfill for geological disposal of radioactive waste: Nirex Reference Vault Backfill. Applied Geochemistry, 106. pp. 120-133. ISSN 0883-2927
Abstract
The ability of Nirex Reference Vault Backfill (NRVB), a cement backfill material, to capture carbon dioxide from Intermediate Level Radioactive waste packages after repository backfilling, has been assessed. Large-scale trials assessed the physical and chemical reaction of carbon dioxide with the hardened backfill grout. A carbonation front, radial in nature, was observed extending into the grout and three distinct regions were identified in the hardened grouts. A carbonated region, a carbonation front, and a partially carbonated zone were discerned. Potassium, and to a lesser extent sodium, were concentrated in the carbonated region just behind of the main reaction front. The area just ahead of the carbonation front was enriched in both sulphur and aluminium, while sulphur was found to be depleted from the carbonated material behind the main reaction front. Within the main carbonated region, virtually all of the hydrated cement phases were found to be carbonated, and carbonation extended throughout the grout, even within material indicated by phenolphthalein solution to be uncarbonated. Importantly, carbonation was observed to impact both the mineral assemblage and porosity of the cement backfill; it is therefore important to understand these characteristics in terms of the long term evolution of NRVB and its groundwater buffering safety function within the geological disposal facility near-field.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 Elsevier Ltd. All rights reserved. This is an author produced version of a paper published in Applied Geochemistry. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | NRVB; Nirex reference vault backfill; Carbon dioxide; Carbonation; Cement; Intermediate level waste; Immobilization; Radioactive; Nuclear |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Civil Engineering (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 21 May 2019 09:45 |
Last Modified: | 08 May 2020 00:39 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.apgeochem.2019.04.020 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:146362 |