Issue 4, 2023

Electrokinetic generation of iron-rich barriers in soils: realising the potential for nuclear site management and decommissioning

Abstract

Following earlier field-scale pilot work on nuclear site materials in the late 2000s, there has recently been renewed research and industry interest in the application of electrokinetic technologies for nuclear site management and remediation in the UK. One relatively novel application of electrokinetics is the use of sacrificial steel electrodes (coupled with an in situ generated pH–Eh gradient in the treated material) to precipitate sub-surface iron-rich barriers for groundwater and/or leachate containment, which could be used to grout or contain contaminated fluids in the sub-surface on working nuclear sites or sites undergoing decommissioning. Here, we report previously unpublished data from two work programmes exploring the higher Technology Readiness Level (TRL) application of this electrokinetic iron-barrier approach to materials typical of those found in the subsurface of the Sellafield nuclear licensed site, UK. The first programme, funded by the UK National Nuclear Laboratory (NNL), assessed the electrokinetic generation of iron-rich barriers at metre + scale in simulated Sellafield materials, while the second programme, funded under the current UK TRANSCEND consortium project, examined electrokinetic iron-barrier formation at smaller (<1 m) scale, but in real site materials. Both programmes indicate that iron-rich barriers can be conveniently and electrokinetically grown in different geometries over reasonable timescales (months) in realistic site subsurface materials (sands), in electrolytes similar to natural waters found in the environment. Voltage requirements are low (<1 V cm−1) with energy and consumables costs of no more than single-digit or tens of US dollars at the metre-plus scale. Further work is needed however to assess the longevity of the iron precipitates forming the subsurface barrier, and to explore barrier generation at the geometries and scales required for (site specific) field application.

Graphical abstract: Electrokinetic generation of iron-rich barriers in soils: realising the potential for nuclear site management and decommissioning

Supplementary files

Article information

Article type
Paper
Submitted
06 Dec 2022
Accepted
28 Feb 2023
First published
06 Mar 2023
This article is Open Access
Creative Commons BY license

Environ. Sci.: Adv., 2023,2, 652-662

Electrokinetic generation of iron-rich barriers in soils: realising the potential for nuclear site management and decommissioning

J. M. Purkis, F. Burrell, J. R. Brydie, J. Graham, L. Hopkinson and A. B. Cundy, Environ. Sci.: Adv., 2023, 2, 652 DOI: 10.1039/D2VA00308B

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