Corrosion analysis of CLAM steel in flowing liquid LiPb at 480 °C

CLAM (China Low Activation Martensitic) steel is considered as the candidate structural material in liquid LiPb blanket concepts of FDS series fusion reactors. To evaluate the kinetics of the corrosion attack exposed to liquid LiPb, long-term exposure tests for specimens of CLAM steel were performed in the DRAGON-I loop more than 8000 h at 480 °C. The exposed specimens were examined by scanning electron microscope and energy dispersive X-ray spectrometer and optical microscope. Moreover, the fresh specimens of CLAM steel were exposed to flowing LiPb at 480 °C for 500 h in order to investigate the mechanism in detail during the early stage of corrosion. X-ray photoelectron spectrometry (XPS) and X-ray diffraction (XRD) analyses were performed before and after exposure, respectively. The results showed that CLAM steel suffered from LiPb corrosion attack due to the dissolution of the passivated layer and the typical steel elements occurred. And the detected corrosion rate is about 17 μm per year.