The mechanical properties of nuclear reactor components degrade as a result of long service exposure in high-temperature, irradiation, and corrosive environments. Fracture toughness and tensile testing are conducted on the pressure tubes of Zircaloy-2 to evaluate the effects of neutron fluence, hydrogen content, and temperature on the mechanical properties. Tensile tests are performed on the base metal, and fracture toughness tests are performed on both the base and weld metals. Neutron irradiation increases the strength, reduces ductility, and significantly degrades fracture toughness. The postirradiation fracture toughness increases substantially as the test temperature is increased from room temperature to 250°C. Hydrogen levels up to 250 ppm are found to have little or no effect on the postirradiation fracture toughness. Because of its anisotropic nature, Zircaloy-2 displays different fracture resistances, depending on crack orientation. In the base metal, the fracture toughness in the longitudinal orientation is higher than that for the circumferential orientation, and this difference is enhanced at higher temperatures. The weld exhibits lower toughness in the longitudinal direction.