Initial, Partition, and End Steam Conditions

A characteristic schematic diagram for a turboset of a typical modern nuclear power unit (for example, with a PWR), with the working fluid's operating conditions corresponding to its 100% maximum continuous rating (MCR), is shown in Figure 2-1. The main (live) steam leaves the reactor's steam generator(s) with a steam pressure of 6.68 MPa (969 psi) and moisture content of 0.25% and enters the double-flow HP cylinder. After this, it passes through the moisture separators (MS) and two-stage reheaters (R) and reaches two or three double-flow, double-exhaust LP cylinders, being superheated to 273 C (523 F) by steam extracted from the HP cylinder (the first reheat stage) and a portion of main steam (the second reheat stage). After the LP cylinders, the working steam passes to the condensers. The resultant steam condensate is pumped through the LP regenerative heaters to the deaerator, from which the feed water is directed by the feed pump(s) back into the steam generator(s) through the HP heaters. The LP and HP regenerative heaters and deaerator are fed with steam from the turbine's steam extractions (bleedings). The turbine's regenerative system also comprises the gland steam condenser and drain coolers. If the feed pumps are driven by steam turbines, the driving turbines are also fed with steam from the turbine's bleedings, most commonly located after the steam reheater. Due to all the steam and water extractions, the rated steam flow amount at the LP cylinder exhausts makes up about 55% of the main...