Compatibility of 9Cr–1Mo steel exposed to thermally convective Pb–17Li

Corrosion behavior of 9Cr–1Mo steel (P91) with flowing Pb–17Li has been studied in a thermal convection loop at a thermal gradient of 100 K between the hot and cold legs and a flow velocity of 6 cm/s. After 1000 h of operation, samples of P91 from both hot and cold legs were analyzed with the help of weight change measurements, Scanning Electron Microscopy coupled with Energy Dispersive Spectrometry (SEM-EDS) and Electron Probe Micro Analysis (EPMA). The results showed preferential dissolution of constituent elements like Fe and Cr from the hot leg samples leading to weight loss, though penetration of Pb–17Li into the inner matrix was not observed. No corrosion was found in the cold leg and the sample surface was found to contain deposits of the elements dissolved from hot leg.