Generation IV Material Issues – Case SCWR

Abstract

Six Generation IV nuclear power concepts becoming global research topics accepted by the GenIV international forum (GIF) with common objectives of pro-moting technological efficiency and safety provide at-tractive features and demanding new challenges e.g., increased operating temperatures, higher irradiation doses, more aggressive coolants, and/or longer life ex-pectations than GenII and GenIII plants. This paper reviews the performance of commercial candidate materials for in-core super-critical water reactor (SCWR) applications focusing on corrosion, stress corrosion cracking (SCC), and creep issues based on work within the Euratom phase 2 high performance light water reactor phase 2 (HPLWR) project. General corrosion, i.e., oxidation rate tests, and SCC tests have been done on selected iron-and nickel-based alloys at 500◦ C and 650◦ C in supercriti-cal water (SCW) at a pressure of 25 MPa with an oxy-gen concentration of 125-150 ppb in all tests. Constant load creep tests have been done on selected austenitic stainless steel at 650◦ C in SCW at 25 MPa and 1 ppm O2 and in inert atmospheres of He and 0.1 MPa. Based on materials studies done during the HPLWR Phase2 project, current candidates for European SCWR core internals are austenitic stainless steels having sufficient oxidation and creep resistance up to 500◦ C or 550◦ C. High chromium austenitic steels and ferritic/martensitic ODS steels are considered, in long-term, for fuel rod cladding thanks to their good oxidation resistances up to 650◦ C.