This presentation throws light on difference between impulse turbine and reaction turbine

3. Energy transformation( i.e from pressure energy to
kinetic energy takes place only in nozzle for impulse
turbine
Reaction turbines don't have nozzle and energy
transformation takes place in both moving as well as
fixed blades

4. Impulse turbines have constant blade channel area as
energy transformation don't have to take place
Reaction turbine have converging blade channel area so
that they can act as nozzle

5. Impulse turbines have profile blade shape
Reaction turbine have airfoil blade shape

6. Impulse turbines have low efficiency due to high losses
Reaction turbine have high efficiency compared to impulse
turbines

7. Impulse turbines have scope for partial admission of steam and
hence both nozzle and throttle governing can be employed for
impulse turbines
Reaction turbines requires full admission of steam and hence
only throttle governing can be used for reaction turbine

8. Impulse turbines are cheap because of easy and low cost
manufacturing and also have low cost maintenance
Reaction turbines are costly because of high cost
manufacturing and also have maintenance cost is also
high

9. Impulse turbines are lighter in weight due to lighter blades
and hence have lower stresses in revolving parts
Reaction turbines are bulkier due to heavier blades and
hence high stresses in revolving parts

10. Impulse turbines have lower leakage losses between blade
tips and casing because of equal pressure across the
clearance
Reaction turbines have high leakage losses between blade
tips and casing because of pressure gradient across the
clearance

11. Impulse turbines are used for lower power generation
Reaction turbines are used for higher capacity of power
generation