Nozzle diaphragms are installed in pressure-compounded impulse turbines to __________.

Correct Answer: Option D — hold the nozzles of the stage and admit steam to moving blades

Nozzle diaphragms secure the stationary nozzle blocks within the turbine casing and direct steam flow at the correct angle against the adjacent moving blades, maintaining stage pressure boundaries in multi-stage pressure-compounded impulse turbines.