Development of reduced activation Ferritic/Martensitic steels for fusion applications

The main goal of the current PhD work is to develop, optimize and characterize reduced activation ferritic/martensitic (RAFM) steels for high temperature applications with improved strength and creep resistance with respect to the reference steel EUROFER97 without compromising low temperature performance of the material. EUROFER 97 steel is a special type of steel developed in Europe, which is foreseen to be used as a structural material in Test Blanket Modules (TBM) in International Thermonuclear Experimental Reactor (ITER).
Optimization work on EUROFER97 has been carried out within the framework of the EUROfusion Consortium as part of the Work Package Materials (WPMAT) group. One of the projects of WPMAT is called Advanced Steels, which is focused on the development of RAFM steels for low temperature (LT) applications as well as RAFM steels for high temperature (HT) applications. During this PhD work, both types of steels were investigated, however, the main focus was on HT alloys. The main goal of the LT development studies is to lower the ductile–to–brittle transition temperature (DBTT) before irradiation, thus allowing a larger operational window in terms of impact properties for the water–cooled fusion reactor design. Research work in HT applications is focused on improving the mechanical properties such as yield strength and creep properties to extend the operating temperature window up to 650 ºC for the helium coolant design.