Modelling the Long-term Corrosion Behaviour of Candidate Alloys for the Canadian SCWR

Abstract

Corrosion behaviour of Inconel 625 and Incoloy 800H, two of the candidate fuel cladding materials for Canadian supercritical water (SCW) reactor designs, were evaluated by exposing the metals to SCW in UNB's SCW flow loop. Individual experiments were conducted over a range of 370°C and 600°C. Exposure times were typically intervals of 100, 250, and 500 hours. Experimental data was used to create an empirical kinetic equation for each material. Activation energies for the alloys were determined, and showed a distinct difference between low-temperature electrochemical corrosion mechanism and direct high-temperature chemical oxidation.