Reliable disk-type rotors for nuclear power plants

Experience gained over the last 15 years has been outstanding with all low pressure (LP) turbine disk-type rotors of the authors' company employed in nuclear power plants. Not a single event of stress corrosion cracking has been found. A total of 40 rotors are in operation averaging close to seven years of service. Eleven of these rotors have been in operation for an average of 59,000 hours with a maximum of 83,000 hours before the first ultrasonic inspection was performed. No stress corrosion cracks were identified by these inspections which, in all cases, covered 100% volume of the entire disk hub bore and keyway area of all rotor disks. Reports of stress corrosion cracking of other disk-type LP rotors, however, initiated extensive research and development work to improve even further the disk-type rotor to a level where it becomes fully competitive with monoblock rotors in regard to equally reliable operating performance