Progress on the Corrosion Screening Tests and Materials Selection for Supercritical Water Cooled Reactors

Abstract

For a pressure vessel type SCWR concept with an outlet temperature of 510°C, the hot spot temperature on fuel the cladding exceeds 600°C at normal operation conditions, and will be much higher during transients. Selection of fuel cladding material is one of the difficulties due to the high corrosion rate of most alloys in supercritical water. Corrosion screening tests have been conducted for more than 3 years on SCWR candidate materials, both commercially available materials and experimental ODS steels. Literature review and corrosion tests showed that the most probable fuel cladding material may have an austenitic structure and contain high Cr concentration up to 22% or higher, such as HR3C and 310. Aluminium is also helpful to improve corrosion resistance in SCW. The excellent performance in corrosion tests shows that alumina forming, high Cr concentration ODS steels are also a possibility for use as SCWR fuel cladding material, assuming the ductility and formability can be increased.