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Modelling geochemical and microbial consumption of dissolved oxygen after backfilling a high level radiactive waste repository

Authors :
Yang, Changbing
Samper, Javier
Molinero, Jorge
Bonilla, Mercedes
Source :
Journal of Contaminant Hydrology. Aug2007, Vol. 93 Issue 1-4, p130-148. 19p.
Publication Year :
2007

Abstract

Dissolved oxygen (DO) left in the voids of buffer and backfill materials of a deep geological high level radioactive waste (HLW) repository could cause canister corrosion. Available data from laboratory and in situ experiments indicate that microbes play a substantial role in controlling redox conditions near a HLW repository. This paper presents the application of a coupled hydro-bio-geochemical model to evaluate geochemical and microbial consumption of DO in bentonite porewater after backfilling of a HLW repository designed according to the Swedish reference concept. In addition to geochemical reactions, the model accounts for dissolved organic carbon (DOC) respiration and methane oxidation. Parameters for microbial processes were derived from calibration of the REX in situ experiment carried out at the Äspö underground laboratory. The role of geochemical and microbial processes in consuming DO is evaluated for several scenarios. Numerical results show that both geochemical and microbial processes are relevant for DO consumption. However, the time needed to consume the DO trapped in the bentonite buffer decreases dramatically from several hundreds of years when only geochemical processes are considered to a few weeks when both geochemical reactions and microbially-mediated DOC respiration and methane oxidation are taken into account simultaneously. [Copyright &y& Elsevier]

Details

Language :
English
ISSN :
01697722
Volume :
93
Issue :
1-4
Database :
Academic Search Index
Journal :
Journal of Contaminant Hydrology
Publication Type :
Academic Journal
Accession number :
25934504
Full Text :
https://doi.org/10.1016/j.jconhyd.2007.01.008