Creep behavior of reduced activation ferritic/martensitic steels irradiated at 573 and 773 K up to 5 dpa

The irradiation creep behavior of F82H and several variants of JLF-l steel has been measured at 573 and 773 K up to 5 dpa using helium-pressurized creep tubes irradiated in HFIR. These tubes were pressurized with helium to hoop stress levels of 0-400 MPa at the irradiation temperature. The results for F82H and JLF-1 with a 400 MPa hoop stress showed small creep strains (<0.25%) after irradiation at 573 K. The irradiation creep strain at 573 K in these steels is linearly dependent on the applied stress at stress levels below 250 MPa. However, at higher hoop stress levels, the creep strain becomes nonlinear. At 773 K, the irradiation creep strain of F82H is linearly dependent on the applied stress level below 100 MPa. At higher stress levels, the creep strain increased strongly. The creep compliance coefficients for F82H and JLF-1 are consistent with the values obtained for other steels. These data contribute to the materials database for ITER test blanket design work. (C) 2007 Elsevier B.V. All rights reserved.