Corrosion Behavior of Candidate Alloys used in Supercritical Water Environment

摘要

Supercritical water reactor (SCWR) isa type of high-temperature and high-pressure water-cooledreactor that could provide higher thermal efficiency thancurrent in-service light water reactors (LWRs). The aim ofthis article is to study the candidate materials with goodcorrosion resistance and appropriate material propertiesthat may be used in SCWR. The emphasis is placed on thecorrosion 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). Thesematerials were tested in the high temperature watercirculation loop with supercritical water environment(550/650°C, 25Mpa). In mass gain analyses, the highentropyalloys and Haynes 230 displayed the bestcorrosion resistance among the four alloys. These alloyswere also evaluated in a supercritical water environmentby U-bend test or creviced bend beam (CBB) test toexamine their resistance to stress corrosion cracking. Themorphologies of the surfaces and cross-section of thesamples were examined by SEM and EDX. Furthermore,the quantitative analysis of the cracks on the surfaces ofthe samples were also carried out.