PRIMARY CIRCULATING PUMP ASSEMBLY

The invention relates to non-volume displacement pumps and can be used at nuclear power plants (NPP) in reactor coolant pump sets (RCPS) for the primary coolant circuit of the nuclear power system. The reactor coolant pump set comprising a vertical vane-type single-stage pump with bottom arrangement of the impeller, the pump shaft is connected to the electric motor shaft by a rigid coupling, the radial-axial bearing, installed in the electric motor upper chamber, is made of two main elements: a radial bearing made in the form of a rotor metallic bushing installed on the cylindrical part of the collar, installed on the motor shaft by way of cone fitting and fastened by means of bolts and a pressure flange on the upper butt of the electric motor shaft, and an axial bearing consisting of two stator lever-type balance arm systems with cover plates of antifriction material and rotor cover plates of antifriction material, installed on the flat part of the collar. The radial-axial bearing is cooled by water from the NPP system, pressure head whereof is increased by the screw-type pump located on the upper butt of the radial-axial bearing collar, and composed of a stator and a rotor bushing with screw thread. The invention is intended for reducing the axial bearing load, increasing reliability and reducing time for axial bearing repair and replacement.