An alloy containing niobioum-20 w/o uranium has been developed for reactor fuel applications. The fabrication characteristics, mechanical properties, and corrosion behavior in air, CO2, NaK, water, and steam were studied. After consumable arc melting, the alloy was successfully forged at 1370°C (2500°F) and rolled at 980°C (1800°F) to sheet. Representative specimens of this alloy showed onlv slight reductions in hardness up to 900°C (1650°F). The 0.2% offset yield strength was 93,000 psi at 24°C (75°F) and 71,000 psi at 870°C (1600°F). At a stress of 63,000 psi at 870°C (1600°F), 200 hr were required to cause rupture. The corrosion life of niobium-20 w/o uranium was superior to that of unalloyed niobium in 300°C (572°F) air and in CO2 at 316°C (600°F). In 1000 hr of exposure to 316°C (600°F) water, this alloy exhibited corrosion rates only two or three (0.003 mg/cm2/hr) times greater than that of Zircaloy-2 (0.001 mg/cm2/hr). This alloy appears to be compatible with NaK at 870°C (1600°F.)