Corrosion of T91 steel and liquid LBE
Generation IV nuclear reactors promise better safety, economic benefits and a potential path to reducing carbon emissions. The liquid lead-bismuth eutectic (LBE) cooled fast reactor is a key Generation IV reactor concept.
In the paper 'Correlated chromium carbide in dissociation and phase transformation in liquid lead-bismuth eutectic corroded T91 steel', published in Corrosion Science, the authors, led by this department, investigated the corrosion of T91 steel after it has been exposed to liquid LBE (T91 steel is a candidate for structural materials in Generation IV reactors). The authors specifically focused on the dissociation of Cr carbides and the overall Cr depletion adjacent to the corrosion interface.
The results suggest a correlation between Cr depletion and phase transformation in steel (most likely ferritisation). The corrosion-induced changes have been analysed from the micro to the atomic scale by combining complementary characterisation techniques: SEM, EDC, (HR)EBSD, DAXM, (S)TEM, EELS and APT.
Based on the investigations, the authors propose a potential mechanism of Cr depletion, Cr carbides dissociation, and phase transformation in T91 induced by LBE exposure. These microstructural changes may alter the mechanical properties, but they are of direct importance to reactor designs, safety and lifetime estimation.
The authors were made up of a collaborative team from Oxford Materials, Oxford Engineering and Cambridge Nuclear Science and Engineering
