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Anaerobic corrosion of carbon steel in compacted bentonite exposed to natural opalinus clay porewater: bentonite alternation study

Morelová, Nikoleta; Schild, Dieter ORCID iD icon; Heberling, Frank ORCID iD icon; Finck, Nicolas ORCID iD icon; Dardenne, Kathy ORCID iD icon; Metz, Volker ORCID iD icon; Geckeis, Horst

Abstract:

Carbon steel is a potential canister material for the disposal of high-level radioactive waste in deep geological repositories in clays and clay rocks. Bentonite is considered as a potential backfill material for those multi-barrier systems.
To predict the long-term performance and for safety assessment the knowledge of canister corrosion behavior is important. The formed corrosion products and mineralogically altered bentonite at the canister/bentonite interface can potentially provide an additional barrier against radionuclide migration.
In-situ corrosion experiments were performed at the Mt. Terri underground research laboratory. Coupons of carbon steel were embedded in Volclay MX-80 bentonite with controlled densities, installed in a borehole under simulated repository and anaerobic conditions and exposed to natural Opalinus Clay porewater for a period up to 5.5 years. The bentonite layer at the canister/bentonite interface was characterized by complementary microscopic and spectroscopic techniques (XPS, SEM-EDX, XRD) under anoxic conditions.
The interface revealed reddish-brown staining up to 2 mm depth into the bentonite in the zone adjacent to the steel. ... mehr


Volltext §
DOI: 10.5445/IR/1000137671
Veröffentlicht am 21.09.2021
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Nukleare Entsorgung (INE)
Publikationstyp Vortrag
Publikationsdatum 08.07.2021
Sprache Englisch
Identifikator KITopen-ID: 1000137671
HGF-Programm 32.11.01 (POF IV, LK 01) Nuclear Waste Disposal
Weitere HGF-Programme 32.11.03 (POF IV, LK 01) Fundamental Scientific Aspects
Veranstaltung Goldschmidt (2021), Online, 04.07.2021 – 09.07.2021
Projektinformation iCross_CO-finanzierung (HGF, HGF IVF2016 SONST, SO-093)
iCross TPC (INE-3) (BMBF, 02NUK053C)
Schlagwörter Bentonite, Corrosion, Steel, XAS,
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