In-pile electrochemical measurements on AISI 316 L(N) IG and EUROFER 97: I: Experimental results

In-pile electrochemical measurements were performed in order to investigate the effect of radiation on the electrochemical corrosion behaviour of two materials: reduced activation ferritic-martensitic steel EUROFER 97 and stainless steel AISI 316L(N)IG. The corrosion potential was continuously monitored during the whole irradiation period. At regular intervals and under various flux levels polarisation resistance measurements and electrochemical impedance spectroscopy were performed. At the end of the reactor cycle polarisation curves were recorded. Analysis showed that the corrosion potential increased and the polarisation resistance decreased with the flux level. The impedance data showed two semi-circles in the Nyquist diagram which contracted with increasing flux level. A fit of the impedance data yielded a decrease of solution and polarisation resistances with the flux level. The polarisation curves could be fitted with a standard Butler-Volmer after correction for the solution resistance and showed an increase in the corrosion current density with the flux level.