Oxidation behaviour of EUROFER-97 under simulated water-cooled breeder blanket conditions
The effect of water chemistry, surface condition, pH moderator (LiOH vs. KOH), and Zn addition was investigated at 300 °C on the oxidation behaviour of reduced activation ferritic martensitic (RAF/M) EUROFER-97. EUROFER-97 is the proposed material for the water-cooled breeder blanket (WC-BB) section of DEMO, but its behaviour under elevated temperature hydrogenated water has never been investigated. Advanced material characterization showed that, despite its relatively low chromium content, EUROFER-97 exhibits high corrosion resistance. This is because it is protected by an inner polycrystalline FeCr2O4 layer, formed regardless of the water chemistry and surface preparation investigated. The outer non-protective oxide consists of Fe3O4 crystallites, which were refined when KOH was used. When injected, Zn was observed only on top of the outer crystallites without diffusing into the inner oxide layer. These findings demonstrate the excellent oxidation behaviour of EUROFER-97 in the proposed water chemistry, highlighting its suitability for the WC-BB section.