Corrosion assessment of high temperature alloys for SCWR fuel cladding design

Supercritical water-cooled reactor (SCWR) is one of innovative next generation reactor concepts. To achieve optimum thermal efficiency, Canadian SCWR concept requires a fuel core outlet temperature of 650 °C at 25 MPa with operating peak temperature possibly up to 850 °C, which leads to one of most challenges of this novel reactor design. Various studies have been performed in the past years and several top-ranking candidate materials, including austenitic stainless steels and nickel-based alloys, are pre-selected based on available public data. To determine which alloy can be for the SCWR fuel cladding application, however, a number of knowledge gaps are needed to be filled. In this paper, our most recent corrosion test results of the alloys are present and the possible corrosion mechanisms are discussed.