Method for disassembling/assembling gas turbine, seal plate assembly, and gas turbine rotor

A method for disassembling/assembling a gas turbine,

• the gas turbine including a seal plate disposed on a first side of a rotor disc in an axial direction of the rotor disc, and a seal plate restraint part for restricting movement of the seal plate relative to the rotor disc in a radial direction of the rotor disc, the seal plate restraint part being disposed entirely on the first side of the rotor,
• the method comprising switching a state of the seal plate restraint part by operating the seal plate restraint part from a second side of the rotor disc that is opposite to the first side in the axial direction to switch between a seal plate non-restraint state where the seal plate restraint part does not restrict movement of the seal plate in the radial direction, and a seal plate restraint state where at least a part of the seal plate restraint part protrudes toward the second side in the axial direction from the seal plate and thereby restricts movement of the seal plate in the radial direction.