Internal properties of disks from the body of a full-integral, low-pressure (LP) rotor forging were investigated. Segregation of alloying elements in forgings from 570-ton ingots is similar to that in forgings from 400-ton ingots, which have been used widely for the production of large rotors for more than 15 years. Distribution of tensile properties is quite uniform throughout the forging. Fracture Appearance Transition Temperature (FATT) is very low in the vicinity of the peripheral surface, increases with increasing depth into midradius, and remains almost constant from midradius to the center of the forging. Distribution of FATT along the length of the body was found, KIc-values converted from JIc are reported at several locations in the forging. Fracture toughness is in the upper shelf region even in the center of the rotor. The discrepancy between the KIc-value converted from valid JIc and valid KIc is discussed.