Corrosion tests have been carried out on AISI 304, AISI 316, WN 1. 4922 (a 12% Cr ferritic steel), Ti 4V 6Al, manganese alloyed austenitic stainless steels (Carpenter 18/18 plus, Nitronic 40 and Nitronic 33) and V 20% Ti exposed in the hot section of a forced (Li-1) and a natural convection loop (Li-01). The corrosion rates have been interpreted as a function of temperature, time, lithium velocity and saturation degree of magnetic trap. The analysis of metallic and non metallic impurities dissolved in lithium and in adherant and non adherant deposits present on AISI 316 substrate material in the heating and cooling section of a thermal convection loop resulted in a description of the mass transfer mechanism of metallic elements in a dynamic lithium system.