The present invention relates to a turbine assembly (10) of a turbine engine (1), comprising at least: a first bladed rotor (12), a bladed stator (13) and a second bladed rotor (14) arranged in series, the rotors (12, 14) being mounted on a shaft (2); a sealing plate (20) extending between the stator (13) and the shaft (2) and separating a first recess (C1) arranged between the first rotor (12) and the stator (13), from a second recess (C2) arranged between the stator (13) and the second rotor (14); and pressure-reducing means (300, 31) positioned inside the first recess (C1), the assembly being characterized in that said pressure-reducing means (300, 31) comprise a plurality of substantially radial recompression fins (300) extending into the first recess (C1).