Evaluation of fatigue properties of reduced activation ferritic/martensitic steel, F82H for development of design criteria

Reduced activation ferritic/martensitic (RAFM) steels are promising candidate for structural material of tritium breeding blanket in a fusion reactor. Database accumulation and definition of design criteria for RAFM have been intensively studied together with the progress of blanket design activities. As a part of database accumulation for fusion blanket, a RAFM steel, F82H was fatigue-tested at 573 and 673 K in the air. Axial strain-controlled fatigue tests were carried out with a cylindrical specimen with 8 mm of diameter with -1 of strain ratio condition in accordance with Japanese Industrial Standard, JIS Z 2279, "Method of high-temperature low cycle fatigue testing for metallic materials." For high cycle tests, the maximum test cycles exceeded 10(6) cycles. Fatigue lifetime of F82H at temperatures ranging from room temperature to 673 K fell into the factor of 2 of the empirical fitting curve for 673 K. It was studied using experimental results that fatigue-related design limit based on RCC-MRx, such as fatigue design curves, half-life cyclic curves, and related coefficients.