Steam turbine rotor, steam turbine and method for actively cooling a steam turbine rotor and use of active cooling

The proposed steam turbine rotor extends along an axial extent and includes: an outer side which adjoins an outer space which is intended to receive a main flow of a fluid working medium, a first location along the outer side, at which a first blade is held, a second location along the outer side, at which a second blade is held, the second location being arranged behind the first location along the axial extent. To ensure sufficient cooling, there is at least one integrated passage, which extends continuously at least between a first region arranged in front of the first location and a second region arranged behind the second location The invention proposes a method and a use in which a fluid cooling medium is guided in a corresponding way.