Question 254Steam Plants - 1st Asst/Chief

The correct answer is D) condenser vacuum. Scale in the air ejector first-stage nozzle can cause a decrease in the condenser vacuum. This is because the scale buildup in the nozzle will restrict the flow of air and other non-condensable gases being removed from the condenser, resulting in a higher pressure in the condenser and a decrease in the overall vacuum. The other options are incorrect because scale in the air ejector nozzle would not directly affect the condensing temperature in the condenser (A), the low-pressure turbine exhaust temperature (B), or the air ejector steam supply pressure (C). The primary impact would be on the condenser vacuum.