Fracture toughness and Charpy impact properties of several RAFMS before and after irradiation in HFIR

Fracture toughness characterization of JLF-1 steel after irradiation in HFIR to 5dpa

“…Room temperature yield strength increased by 314 MPa (from 525 MPa in the unirradiated condition to 839 MPa after irradiation). This result is in agreement with available hardening measurements on JLF-1 steel [8,9], but somewhat less than observed for such irradiation conditions on Eurofer97 [10,11] and F82H [3,12,13] steels. The observed hardening suggested a transition temperature shift after the same irradiation level of at least 100°C.…”

“…The current data allow comparison of the radiation embrittlement of JLF-1 steel with F82H and 9Cr-2WVTa data since those steels were irradiated in the same temperature range and to similar doses [13], see Fig. 3.…”

Embrittlement of irradiated F82H in the absence of irradiation hardening

“…The reduced-activation steel F82H-IEA heat (nominally Fe-7.5Cr-2.0W-0.15V-0.02Ta-0.09C) was irradiated in the High Flux Isotope Reactor (HFIR) in the normalized-and-tempered condition [12,13]. Normalization involved austenitizing at 1040°C to transform the steel to austenite, after which it was air cooled to form 100% martensite.…”

“…One-third-size pre-cracked Charpy (PCVN), Charpy V-notch (CVN), and 0.18 T disk-compact fracture toughness [DC(T)] specimens were irradiated in HFIR to %3-5 and 20 dpa at 300-500°C [12,13]. The low-dose irradiation was in two capsules in reactor removable beryllium positions, and the 20 dpa irradiation was in a capsule in the target position [13].…”

Recent progress toward development of reduced activation ferritic/martensitic steels for fusion structural applications

“…As an example of such embrittlement, the authors cite the work of Sokolov et al who found embrittlement of F82H irradiated in HFIR at 500°C due to Laves phase. The embrittlement occurred despite a decrease in yield stress [15]. Consequently there is a need for high-dose irradiation experiments above the irradiation-hardening regime [14].…”