The turbine in which the steam expands while passing over the moving blades as well as while passing over the fixed blades and the pressure of steam decreases gradually throughout the flow is called reaction turbine. Parsons turbine is an example of reaction turbine. In these turbines the pressure drop during the expansion of steam occurs within the moving and fixed blades. Thus the rotation of shaft is due to both impulsive and reactive forces in the steam.
One stage of reaction turbine consists of 1 row of fixed blades followed by row of moving blades. The fixed blades behave as nozzle. Fixed blades are attached to inside of cylinder whereas the moving blades are fixed with rotor. The rotor is mounted on shaft further.