b'The development of advanced oxide dispersion strengthened (ODS) ferritic alloys such as 14YWT and OFRAC offer many advantages over conventional steels for fuel cladding in sodium cooled fast reactors such as high temperature creep strength and improved tolerance to high dose neutron irradiation environments. high temperatures while maintainingcating useful parts such as thin wall structural integrity in contact withtubes. Thus, in this project, research the fuel and coolant. The claddingis focused on improving the high material must meet this challengingtemperature strength of HT-9 and on environment while possessing thedevelopment and fabrication of oxide ability to be fabricated into thin walldispersion strengthened alloys, such as tubing and joined by welding.14YWT and a new alloy referred to as Project Description: OFRAC into thin wall tubes. The leading candidate for high doseAccomplishments: environments of sodium-cooled fastBuilding upon extensive research and reactors is 12Cr-1MoVW (HT-9)development of the nanostructured ferritic/martensitic steel (F/M steel)ferritic alloy (NFA) 14YWT starting due to its resistance to irradiationin 2001 at ORNL, a new NFA referred induced swelling and creep up toto as OFRAC was developed for 550C. For higher thermal efficiencyadvanced fuel cladding in sodium of fast reactors, advanced materials arefast reactors (SFR) starting in 2016. required that can perform at higherThe composition of OFRAC is irradiation temperatures. AdvancedFe-12Cr-1Mo-0.3Ti-0.3Nb-0.3Y2O3 radiation tolerant materials containing(wt.%). The purpose for selecting a dispersion of nano-size oxide parti- this composition was to promote cles are being developed to meet thepartial phase transformation of the higher irradiation temperatures andmicrostructure to form grains of the enable higher fuel burnup. Although-fcc (face centered cubic) austenite the high strength properties and radia- phase at high temperatures between tion tolerance of the oxide dispersion~910C and ~1125C from the alloys are attractive, these alloys alsomatrix consisting of -bcc (body present greater challenges in fabri- centered cubic) ferrite phase during 2019|AFC ACCOMPLISHMENTS 187'