Development of reduced activation ferritic/martensitic steels in China

Reduced-activation ferritic-martensitic (RAFM) steel is considered as the primary candidate structural material for blankets of ITER, CFETR and DEMO. Several RAFMs have been developed in China (CN-RAFMs) such as CLAM, CLF-1, modified RAFMs and oxide dispersion strengthened RAFMs (ODS-RAFMs). The mechanical properties, irradiation behaviors, additive manufacturing and joining technologies of structural materials have been comprehensively studied. Qualifications of CN-RAFMs are on-going for ITER-TBM fabrication, with emphasis on material property databases and standardization. A new neutron irradiation program is being carried out for a series of fusion materials e.g. RAFMs and ODS-RAFMs with doses up to 40 dpa. Joining technologies (e.g. electron beam welding, tungsten inert gas welding, laser beam welding and diffusion welding, etc.) and advanced additive manufacturing are performed to overcome the big challenges of the blanket fabrication before ITER, CFETR and DEMO. The databases and standards for CLAM and CLF-1 were established respectively, and the specification and qualification of them are underway for ITER-TBM. In this paper, the latest development and strategy on fusion energy in China are briefly introduced, and the progresses of R&D activities on CN-RAFMs aiming for the engineering applications are reviewed.