Individual Project 12 << back

Overview

Industrial sector: power supply facilities
Research sub-programme: nuclear waste geological disposal

Host partner: CNRS-LISE - Paris, France

Associated partner involved: AREVA

Recruited researcher: Rebeca MOREIRA

Scientist-in-charge: Bernard TRIBOLLET


Description

Title: the interface mechanism of iron biocorrosion in presence of IRB (Iron Reducing Bacteria) in clay environment

Field problem addressed:

Safe nuclear waste disposal is a major challenge for nuclear energy suppliers in the next decades. High activity waste will be stored in carbon steel containers placed deep underground (500m) in argillaceous formations. Anoxic corrosion of the containers will produce H2 which can represent a major hazard when accumulating for years in the surrounding clay stone. This H2 production will represent a new energetic source for bacterial development especially in such environment containing a low amount of biodegradable organic matter. H2 could then contribute to the growth of bacteria and biofilms on the stainless steel containers which in turn could contribute to biocorrosion. Biocorrosion of carbon steels, as used in nuclear waste disposal is a real risk only when it promotes fast local corrosion.



Objectives:


To characterize the electrochemical interfaces in order to obtain the mechanisms of carbon steel biocorrosion in presence of IRB and HOB in clay environment. The main point for the IP12 is the electrochemical aspect with both local and global techniques. In particular identification of element and nutrient fluxes at the interfaces able to support the reactivity (proton exchange, hydrogen consumption, Fe(0), Fe2+, Fe3+) will be obtained by local electrochemical measurements (Scanning Electrochemical Microscopy and local specific sensors), and the local kinetics will be studied by Local electrochemical Impedance Spectroscopy.
The common goal of IP11 and IP12 is to understand the evolution with time of H2 concentration and of the local biocorrosion of carbon steel by IRB and HOB in clay environment. The impact of these bacteria on biocorrosion phenomena is unknown.