Patent Number: 050842366
Section: abstract

A nuclear reactor coolant pump for pumping reactor coolant fluid in a reactor coolant system includes a casing, a rotor and an impeller. The casing defines an inlet nozzle for receiving the fluid, a peripheral outlet nozzle for discharging the fluid, and a passage interconnecting the inlet and outlet nozzles through which the fluid can flow from the inlet to outlet nozzle. The rotor extends axially through the casing and has an end disposed adjacent passage. The impeller is mounted to the end of the rotor and disposed in communication with the passage and offset axially from the outlet nozzle of the casing. The impeller is rotatable with the rotor for drawing fluid into the casing through the inlet nozzle and discharging fluid from the casing tangentially through the peripheral outlet nozzle after flow through the passage. The outlet nozzle is composed of first and second wall portions defined above and below a plane extending generally parallel to the rotation axis of the impeller. The first wall portion has a substantially semi-cylindrical shape, whereas the second wall portion has a combined substantially semi-elliptical and semi-conical shape.