Potential influence of microorganisms on the corrosion of carbon steel in the French high‐level long‐lived radioactive waste disposal context at 80°C

• Published in: Materials and corrosion 2023-11, Vol.74 (11-12), p.1795-1810
• Main Authors: Diler, Erwan, Leblanc, Vanessa, Gueuné, Hervé, Maillot, Valérie, Linard, Yannick, Charrier, Gaëlle, Crusset, Didier
• Format: Article
• Language: English
• Subjects: Alkalinity; Biotic conditions; carbon steel; Carbon steels; cement; Cement grouts; Cements; claystone; Claystones; Condition; Context; corrosion; Corrosion risk; disposal; Fillers; Filling materials; Grout; High level radioactive waste disposal; Inoculum; Long-lived radioactive wastes; microbially influenced corrosion; Microbially-influenced corrosions; Microorganisms; Microwave integrated circuits; Nutrients; Polymerase chain reaction; radioactive waste; Radioactive waste disposal; Radioactive wastes; Radioactivity; Reaction kinetics; Research laboratories; Risk assessment; Risk management; Steel corrosion; Underground corrosion
• ISSN: 0947-5117; 1521-4176; 1521-4176
• DOI: 10.1002/maco.202313899

In this study, experiments were carried out to assess the microbially influenced corrosion (MIC) risk in the context of the French high‐level radioactive waste disposal. The exposures were carried out at 80°C in different repository relevant conditions, including the presence of different cement‐grout mixtures as filling material. Biotic conditions with nutrient and nonsterile conditions with indigenous microbes added from Callovo Oxfordian clayey rock and without nutrients were considered. For biotic conditions, specific preparations of microbial inoculum were carried out from samples collected at Andra's Underground Research Laboratory and microorganisms from microbial culture collection centers. Corrosion kinetics were determined using traditional coupons and completed with real‐time corrosion sensors. Microbiological characterizations consisted of cultural approach, quantitative polymerase chain reaction, and next‐generation sequencing. The obtained results show no significant MIC and a reduced risk with the use of more alkaline filling material. Microbially influenced corrosion (MIC) risk is assessed in the context of the French high‐level radioactive waste disposal. Experiments were carried out in different media with complementary microorganisms from underground research laboratory and culture collection centers. After 6 months at 80°C, no MIC was observed, with a reduced risk using more alkaline filling material.