Investigation of Oxidation Behavior of 304L and 310S Steels with Potential Application in Supercritical Water-cooled Nuclear Reactors

Selecting proper candidate materials is one key issue for the development of the supercritical water-cooled nuclear reactor (SCWR). Designing or choosing the most fitting materials means better sustainability, economics and safety. As the supercritical water is a very aggressive corrosive media, corrosion becomes one challenging problem for the materials used in the SCWR. This paper involves the corrosion testing of two stainless steels (304L and 310S) and microstructure evaluation of samples after being exposed to supercritical water. The test parameters were set at the temperature of 550oC and the pressure of 25 MPa for up to 63 days. The samples were investigated using gravimetric corrosion test, optical microscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. Results showed a lower corrosion performance, in terms of weight change and surface oxide formation, for 304L due to its low chromium content. 310S has excellent corrosion resistance because the chromium content is higher. The results obtained will be useful in future research of test protocol and development of alloys that could be used as reactor fuel cladding and other components in the SCWR.