Abstract
Supercritical water reactor (SCWR) is a type of high-temperature and high-pressure water-cooled reactor that could provide higher thermal efficiency than current in-service light water reactors (LWRs). The aim of this article is to study the candidate materials with good corrosion resistance and appropriate material properties that may be used in SCWR. The emphasis is placed on the corrosion phenomena and stress corrosion cracking (SCC) of the four selected alloys including nickel-based alloy (Haynes230), martensitic steels (P92), austenitic steels (304H) and high-entropy alloys (Al Co Cr Fe Ni Ti). These materials were tested in the high temperature water circulation loop with supercritical water environment (550/650 C, 25Mpa). In mass gain analyses, the high-entropy alloys and Haynes 230 displayed the best corrosion resistance among the four alloys. These alloys were also evaluated in a supercritical water environment by U-bend test or creviced bend beam (CBB) test to examine their resistance to stress corrosion cracking. The morphologies of the surfaces and cross-section of the samples were examined by SEM and EDX. Furthermore, the quantitative analysis of the cracks on the surfaces of the samples were also carried out.