Gavrilov, Serguei

Schroer, Carsten

Stergar, Erich

Tsisar, Valentyn

English

KITopen

Valentyn Tsisar a, Serguei Gavrilov a, Carsten Schroer b, Erich Stergar aEUROCORR – 20207th - 11th SeptemberVirtual congressa SCK•CEN, Belgium; b KIT, Germany. Long-term corrosion performance of T91 ferritic/martensitic steel at 400 °C in flowing Pb-Bi eutectic with  ~10−7 mass% dissolved oxygenEUROCORR – 2020MotivationMYRRHA -Multi-purpose hYbrid Research Reactor for High-tech Applications2Pb-Bi eutectic – spallation target and coolantEUROCORR – 2020BackgroundCorrosion3Ni, Cr, FeAustenitic steelPb, BiPure Pb-Bi de-alloys intensively steels at high temperaturesCorrosion zoneEUROCORR – 2020Background4I.V. Goryninet al. Met. Sci. Heat Treat. 41 (9) (1999) 384–388.550°C, 3000h1 and 2 – austenitic steels of 316L typeCorrosion loss (µm)Transition zoneOxygen concentration in Pb (mass %) Corrosion mitigation approachIn-situ oxygen addition into Pb-BiEUROCORR – 2020Background5Thermodynamic Pb-Bi dissolves andtransports oxygen Si, Cr, Fe form stable oxidesin Pb-Bi[O]Schroer, C., Konys, J. FZKA 7364, 2007EUROCORR – 2020 General aimCorrosion performance of steels under MYRRHA conditions6 Main taskOptimum parameters to minimize corrosion Current activityReliable quantitative data on corrosion of steelsIntentionsEUROCORR – 2020Methods7CRAFT forced-convection Pb-Bi loopCorrosion Research for Advanced Fast reactor TechnologiesEUROCORR – 2020MaterialsFe-9Cr ferritic-martensitic steel T918Thermal treatment: normalization 1050 °C/15 mintempering at 750 °C/45 minMicrostructure: tempered martensiteprecipitates:M23C6 (M – Cr, Fe, Mo)MX (M – V, Nb and X - C, N)Microstructure reconstructed by ARPGE program:grain size ~20 μm - ASTM No 8.0 (E112–13).Cylindrical samples:Ø8 × 35 mmSurface finishing:fine turningspiral grooves:width 80 µmdepth 0.9 μm.EUROCORR – 2020 9Test parametersResultsT= 400 °CCO[Pb-Bi]= 2×10-7 mass%OFlow velocity= 2 m/sTime~ 20,000 hEUROCORR – 2020Results10General uniform oxidationEUROCORR – 2020Results11Bilayer magnetite scale: Fe3O4/Fe(Fe,Cr)2O4Features of oxidationEUROCORR – 2020Results12Kinetics of oxidationParabolic rate lawy2 = k t + CFe3O4Fe(Fe,Cr)2O4Data from CRAFT and CORRIDA loops agree wellEUROCORR – 2020Results13Kinetics of oxidationCorrosion rate ~ 4 µm/yearEUROCORR – 2020Results14Features of oxidation Local incomplete oxidation Local buckling of scale Penetration of Pb-Bi to the scale/steel interfaceEUROCORR – 2020Results15Surface examinationsSegment of samples cleaned from Pb-Bi EUROCORR – 2020Results16Localized dissolution corrosion attack: ~100 µm after 20,000hEUROCORR – 2020Results17Localized dissolution corrosion attackNon-selective dissolutionEUROCORR – 2020Results18Kinetics of local dissolutionCorrosion rate ~ 20 µm/yearIncubation time ~ 2000 hEUROCORR – 2020Summary19Corrosion: T91 steel showed major oxidation - bilayer scale Fe3O4 / Fe(Fe,Cr)2O4 Corrosion rate due to oxidation ~ 4 μm/year; Localized dissolution corrosion rate ~ 20 μm/year;CRAFT loop operation: Long-term (20,000 h) and stable operation with target parameters is achieved for the CRAFT loop in this experimental campaign;CRAFT + CORRIDA loops: Complimentary data are obtained in different installations.EUROCORR – 2020Concluding remarks201. Applicability of in-situ oxygen addition to liquid Pb-Bi in orderto stimulate oxidation of steel and avoid dissolution isdemonstrated in this work based on the long-term test;2. Local degradation of Fe-based oxide scale with time is an issue;3. Improvement of the durability of oxide layers is a mainchallenge for further investigations.More details in: V. Tsisar, et al. Corrosion Science 174 (2020) 108852EUROCORR – 2020 21Copyright © SCK CEN - 2020All property rights and copyright are reserved.This presentation contains data, information and formats for dedicated use only and may not be communicated, copied, reproduced, distributed or cited without the explicit written permission of SCK CEN.If this explicit written permission has been obtained, please reference the author, followed by ‘by courtesy of SCK CEN’.Any infringement to this rule is illegal and entitles to claim damages from the infringer, without prejudice to any other right in case of granting a patent or registration in the field of intellectual property.SCK CENBelgian Nuclear Research CentreStudiecentrum voor KernenergieCentre d'Etude de l'Energie NucléaireFoundation of Public UtilityStichting van Openbaar Nut Fondation d'Utilité PubliqueRegistered Office:Avenue Herrmann-Debrouxlaan 40 - 1160 BRUSSELS - BelgiumResearch Centres:Boeretang 200 - 2400 MOL - BelgiumChemin du Cyclotron 6 - 1348 Ottignies-Louvain-la-Neuve - BelgiumThank you for your attention!

Long-term corrosion performance of T91 ferritic/martensitic steel at 400 °C in flowing Pb-Bi eutectic with 2 × 10$^{-7}$ mass% dissolved

https://publikationen.bibliothek.kit.edu/1000123939/88244691

Long-term corrosion performance of T91 ferritic/martensitic steel at 400 °C in flowing Pb-Bi eutectic with 2 × 10 $^{-7}$ mass% dissolved

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Long-term corrosion performance of T91 ferritic/martensitic steel at 400 °C in flowing Pb-Bi eutectic with 2 × 10−7^{-7}−7 mass% dissolved

Abstract

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Long-term corrosion performance of T91 ferritic/martensitic steel at 400 °C in flowing Pb-Bi eutectic with 2 × 10 $^{-7}$ mass% dissolved