Abstract: A stress corrosion cracking proof steam turbine in which dry steam is blown into the gap between the hub portions of adjacent turbine discs, thereby preventing corrosion in the gap. A nozzle diaphragm is provided between the discs and has an inside circumferential face which straddles the gap. Labyrinthine packing is provided on the inside face of the nozzle diaphragm and comprises an upstream, an intermediate, and a downstream group of fins. A steam reservoir is located between the intermediate and downstream group of fins and straddles the gap. A steam supply means is located inside the nozzle diaphragm and provides dry steam (from inside or outside the turbine) to the reservoir and thus to the gap. To prevent leakage of high pressure wet steam into the reservoir, a steam leakage capturing means is provided between the upstream and the intermediate group of fins.

Abstract: A turbine rotor has a shaft, a plurality of wheel discs shrunk-fit on said shaft along the axial direction thereof, said wheel discs being provided with blades on the outer circumference thereof. A plurality of coupling members are disposed between the wheel discs except the ones disposed most downstream, for coupling the wheel discs to each other. At least one coupling means is disposed between the wheel disc disposed most downstream of the shaft.