Selection of Steam Turbines For Nuclear Power Plant

The steam produced in a nuclear power plant is mostly saturated unlike in the conventional fossil fuel plants where steam is produced with a high degree of superheat. This necessitates a much higher mass and volume of steam to be passed through the turbine for the same capacity as in conventional plants. The physical size of the turbine thus becomes much larger compared to the conventional plant. Moisture in the steam causes severe erosion problems, particularly in the high-pressure turbine. Removal of water and reheating of steam becomes essential before admission into the lowpressure turbine. An effort has been made in this paper to discuss the selection criterion for turbines in Nuclear Power Plants of the Pressurised Heavy Water Reactor type with specific reference to the turbine for the 500 MWe NPP at Tarapur.