Chapter 24. -NUCLEAR POWER PLANTS 



FROM OTHER 

 STEAM GENERATORS 



HEAT OUTPUT 



- 790 X 10« 8TU / MR 

 FLOW . 50,400 GPM 

 OPERATING PRESSURE 

 = 2000 PSI 

 DESIGN PRESSURE 



. 2500 PSI 



■ STEAM PRESSURE - 600 PSIA 

 . STEAM FLOW . 287,000 LBS.'HR 



STEAM 

 GENERATOR 



STEAM 

 SEPARATOR 



'////////////////^y 



^ GENERATOR ^ 

 /, 60,000 - KW NET ^ 

 X OUTPUT (SLOOPS)^ 



. FLOW = 1^800 GPM 

 VELOCITY . 30 FT/SEC 



CONDENSATE 

 PUMP 



FEEDWATER 

 i PREHEATER 



-C5c- 



BOILER FEED PUMP 



LOOP NO. 3 



TOOTHER STEAM GENERATORS 



147.158X 



Figure 24-8.— Schematic diagram of PWR plant. 



flows upward between the fuel plates, with 

 the remainder bypassing the core in order to 

 cool the walls of the reactor vessel and the 

 thermal shield. After having absorbed heat as 

 it goes through the core, the water leaves the 

 top of the reactor vessel through the outlet 

 nozzles and flows through connecting piping to 

 the steam generator. 



The steam generator is a shell-and-tube 

 type of heat exchanger with the primary coolant 

 (reactor coolant) flowing through the tubes and 

 the secondary water (boiler water) surrounding 

 the tubes. Heat is transferred to the secondary 

 water in the steam generator, producing high 



quality saturated steam for the use in the 

 turbines. 



The primary coolant flows from the steam 

 generator to a hermetically sealed (canned 

 rotor) pump (fig. 24-10) and is pumped through 

 connecting piping to the bottom of the reactor 

 vessel to complete the primary coolant cycle. 

 The pressure on the reactor vessel and the 

 main coolant loop is maintained by a pres- 

 surizing tank (fig. 24-11) which operates under 

 the saturation conditions of 636° F and 2000 psia. 

 A second function of the pressurizing tank is to 

 act as a surge tank for the primary system. 

 Under no load conditions the inlet, outlet, and 

 average temperatures of the reactor coolant 



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