Steam turbines in nuclear plants normally has saturated steam at the inlet, then that condition need to be considered during the design and for maintenance. the low isoentropic efficiency of the stages avoid lower steam quality.

Many steam turbines of the nuclear power plants has two parts in series, the high pressure steam turbine and the low pressure steam turbine. The high pressure steam turbine operates with saturated steam as says R. Borrajo and the low pressure operates with reheated steam that in the second or third stage pass to saturated steam. To avoid the blade damage due to the condensated steam, the extractions to the heaters are designed to drain the wáter and so the steam to the next turbine stage is more dry.

Ruben Borrajo : Thank you for your response. Would you happen to know what the typical isentropic efficiency of stages in between would be? And plus, any design limitations for the steam exit quality?

Emilio Casado: Thank you for your response. The data for the draining mechanism is not well exposed in academic settings. Would there be any rule of thumb for determining the amount of drained water?

It depends of the turbine design. For example, the high pressure steam turbine of a 1000 Mwe PWR nuclear power plant, in the steam extraction to the heater number 6, the quantity of wáter could be 2%.