Advances in materials evaluation for the Canadian SCWR core concept

Canada has, since 2007, undertaken research to develop a conceptual design of a pressure-tube based supercritical water-cooled reactor (SCWR). With an outlet temperature of 625 degree C and a coolant pressure of 25 MPa, this concept requires fuel-cladding materials that can sustain high-temperature and high-pressure in-core conditions. An overview of the key aspects of the design related to in-core materials and the recent development of materials assessment of this program are presented in this paper. Much progress has been made in selection and testing of candidate alloys, and the more rewarding scientific outcome of the program is the fact that significant amount of knowledge has been gained of the mechanisms and factors of key microscopic processes taking place under SCWR in-core conditions. Further materials R&D work should focus on improving the resistance to stress corrosion cracking (SCC) and irradiation-assisted SCC, high-temperature strength and ductility as well as microstructural stability.