Westinghouse Electric Corporation

Westinghouse Electric Company LLC

James A Drake

Luciano Veronesi

Raymond M Calfo

Joseph M Kujawski

Clifford H Campen

Leonard S Jenkins

Carl W Bergmark

Cracks in the shaft of a reactor coolant pump adjacent a tapered end on which the impeller is mounted are removed by machining a circumferential groove in the pump shaft to a depth and an axial length which removes the cracks but does not extend into the tapered end of the pump shaft. A split ring fills the groove to an outer diameter which matches the outer diameter of the pump shaft. A thermal sleeve shrink fit over the split ring has internal annular ribs engaging the shaft and the ring to form an annulus which communicates with the pump chamber sufficiently to maintain a layer of substantially stagnant coolant over the split ring and the pump shaft at the pressure of the coolant being pumped. An oversized washer between the impeller and the impeller retainer nut overlaps the interface between the impeller and the tapered end of the pump shaft to impede the flow of hot reactor coolant along the keyways in the tapered end of the shaft and the impeller to minimize temperature fluctuations in the vicinity of the thermal sleeve. Preferably, the thermal sleeve has a lower coefficient of thermal expansion than those of the shaft and the split ring.

Method of repairing a reactor coolant pump shaft and a reactor coolant pump repaired by such method

A thermal barrier for a nuclear reactor coolant pump includes a stack of pancake cooling coils encircling the pump shaft where it enters the pump chamber. This stack of coiling coils has an irregular peripheral surface formed by axially extending, diametrically opposed, inlet and outlet tubes which are circumferentially indexed for each pancake coil. The inner surface of a cylindrical cover has a complimentary inner peripheral surface formed by two sets of diametrically opposed cascaded steps so that the volume of the annulus between the coil stack and cover is minimized to reduce stratification of cooling water injected into the cover. A collar around the pump shaft at the opening in the end wall of the cover extends axially into the coil stack to prevent vortices produced by the spinning shaft from flowing across the end wall of the cover, while circumferentially spaced holes in the collar prevent significant alteration of the thermal conditions of the pancake coiling coils. An integral flange on the collar serves as a shim for the stack of coils. An external insulator includes a sleeve with a low coefficient of thermal expansion shrink fit over a groove in the outer surface of the cylindrical cover to form an annular chamber which is divided by a number of nested cans into a plurality of concentric sections each containing stagnant reactor coolant.

Thermal barrier and reactor coolant pump incorporating the same

An auxiliary thruster for a marine vessel. The auxiliary thruster includes a submersible propulsion unit which has a shroud with a propeller rotatably mounted therein. A canned electric motor is mounted between the propeller and the shroud for rotating the propeller to create thrust. A propulsion unit deploying and rotating mechanism is mounted on the hull and on the propulsion unit. The propulsion unit deploying and rotating mechanism is operable to extend the propulsion unit out of the hull and retract it into the hull and to rotate the propulsion unit to direct the thrust generated thereby in any desired direction when the thruster is in the deployed position. When the thruster is retracted, it is positioned with a tunnel extending transversely through the hull. Rotation of the propeller while in the retracted position generates laterally directed thrust through the tunnel.

Combined azimuthing and tunnel auxillary thruster powered by integral

A fluid pump powered by an integral canned motor includes a housing having a cylindrical passage extending therethrough. A sealed annular stator is mounted around the housing. An impeller assembly is rotatably mounted in the passage in the housing. The impeller assembly includes an axial flow impeller and a sealed rotor mounted around the periphery of the impeller. Bearings, including thrust bearings, are mounted between the periphery of the impeller assembly and the housing. A radial flow auxiliary impeller may be mounted on the impeller assembly to create a radial flow of water from the cylindrical passage in the housing to a peripheral fluid circulation channel between the impeller assembly and the housing. The auxiliary flow impeller pressurizes the peripheral fluid circulation channel.

High speed fluid pump powered by an integral canned electrical motor

A water jet propulsor powered by an integral canned electric motor includes a hollow housing having a hermetically sealed stator mounted therein. The stator is electrically connected to a source of electrical energy in the vessel. An impeller assembly that includes a tubular suction shroud and impeller is rotatably mounted inside the housing. The impeller assembly includes a hermetically sealed rotor which is mounted around the suction shroud and positioned inside the stator in operative association therewith. Energizing the stator rotates the rotor, which in turn rotates the impeller to pump water from the intake end of the housing to the outlet end of the housing and adds velocity and head to the water to be discharged from the outlet end. The discharged water creates thrust which propels the vessel.

Water jet propulsor powered by an integral canned electric motor

The submersible propulsor unit of the invention comprises a cylindrical shroud having a water inlet and a water outlet, a propeller having a hub rotatably mounted within the shroud on a shaft, and an electric motor for driving the propeller that includes a rotor mounted around the periphery of the propeller, and a stator circumscribing the shroud, and a bearing assembly that includes means for circulating ambient water around the bearing surfaces to both lubricate and cool them. A stationary cover is detachably secured over the bearing assembly on the water inlet end of the shaft to provide easy access to the bearings in the bearing assembly The vane members that concentrically mount the shaft within the interior of the shroud are, in one embodiment, all connected on the downstream side of the propeller to reduce the cavitation and resulting noise when the propeller rotates. The magnetization of the rotor is provided by a plurality of permanent magnets for both improved efficiency, and lower noise. A squirrel cage structure formed from damper bars and conductive wedges is integrated over the magnets of the rotor both to assist in the starting of the motor, as well as to insulate the magnets from harmonic currents that could act to de-magnetize them. In one embodiment, the propulsor unit has a single propeller driven by two identical side-by-side motor assemblies. This arrangement provides added reliability while retaining mechanical simplicity and low cost and weight as compared with a multipropeller propulsor unit.

Integral motor propulsor unit for water vehicles with plural electric

The submersible propulsor unit of the invention comprises a cylindrical shroud having a water inlet and a water outlet, a propeller having a hub rotatably mounted within the shroud on a shaft, and an electric motor for driving the propeller that includes a rotor mounted around the periphery of the propeller, and a stator circumscribing the shroud, and a bearing assembly that includes means for circulating ambient water around the bearing surfaces to both lubricate and cool them. A stationary cover is detachably secured over the bearing assembly on the water inlet end of the shaft to provide easy access to the bearings in the bearing assembly. The vane members that concentrically mount the shaft within the interior of the shroud are all connected on the downstream side of the propeller to reduce the cavitation and resulting noise when the propeller rotates. The magnetization of the rotor is provided by a plurality of permanent magnets for both improved efficiency, and lower noise. A squirrel cage structure formed from damper bars and conductive wedges is integrated over the magnets of the rotor to assist in the starting of the motor, as well as to insulate the magnets from harmonic currents that could act to de-magnetize them.

Integral motor propulsor unit for water vehicles

A pivoted pad bearing assembly of the Kingsbury type provides for leveling of bearing pads arranged in a circular array utilizing hydrostatic pressure rather than mechanical links. The leveling device is in the form of a hydraulic bearing support module having a variable volume hydraulic chamber. Pipe segments connect each hydraulic chamber to form a closed circuit and the circuit is completely filled with hydraulic fluid. Thereby, equal force will be exerted upon each pad at all times so that all pads will operate at an equal thrust load. The bearing assembly has particularly useful application in an integral motor submersible propulsor as a large diameter thrust bearing housed within an outer shroud of the propulsor at both upstream and downstream ends of a rotor mounted about the periphery of a propeller of the propulsor. By placing the thrust bearing within the shroud, greater thrust bearing surface areas can be obtained to handle larger thrust. By using hydrostatic leveling, the noise associated with mechanical linkages is avoided, and the size and weight of the bearing assembly can advantageously be reduced.

Bearing assembly and submersible propulsor unit incorporating the same

A high-thrust, shock-resistant submersible propulsor unit comprises of a shroud having a water inlet and a water outlet, a shaft assembly centrally mounted within the shroud, and an upstream and a downstream propeller, each of which includes a separate hub rotatably mounted on the shaft assembly, first and second electric motors for independently rotating the upstream and the downstream propellers, wherein each motor includes a rotor mounted around the outer periphery of one of the propellers, and a stator mounted on the shroud around the rotor, and first and second bearing assemblies, each of which includes a thrust bearing disposed within the hubs of the upstream and downstream propellers in the shaft assembly, wherein the thrust bearings associated with the first and second bearing assemblies are located on opposite ends of the shaft assembly. Each of the bearing assemblies includes a removable cover which affords easy and separate access to the bearing contained in each. The pitch of the upstream and downstream propellers is different so that they may be counter-rotated to produce torque free thrust. In the preferred mode of operation, the propellers are rotated at different speeds such that the upstream propeller supercharges the downstream propeller.

Dual propeller shock resistant submersible propulsor unit

Both a closed system and method for cooling a submersible propulsor unit for a water vehicle is provided for a unit of the type that includes a submersible motor having a shaft connected to a propeller, and a housing containing the motor. The system comprises a motor cooling assembly that includes a shaft seal for conducting the shaft outside of the housing while preventing ambient water from entering the housing, a liquid contained within the housing for cooling the motor, a heat exchanger for thermally connecting but mechanically isolating the liquid from the ambient water, an impeller (102) for recirculating the liquid through both the motor and the heat exchanger, and a bellows (128) for equilibrating any pressure differentials between the cooling liquid and the ambient water. A filter assembly (129) mounted within the bellows relieves any pressure differential that is not relieved by the bellows when ambient water pressure is greater than that of the cooling liquid in the housing. The filter assembly removes particulate debris from the ambient water before admitting it into the housing, to relieve the pressure differential, and may further include an osmotic membrane for preventing dissolved salts in ambient water from entering the cooling liquid.

System and method for cooling a submersible electric propulsor

A deep beam head for a nuclear reactor and an improved reactor containing such a head where the upper horizontal support plate of a calandria in the reactor forms a sealing plate for the reactor vessel. The sealing plate has a ring member about the upper periphery thereof that is secured to the top of the pressure vessel cylindrical wall and reinforcing members extend across the sealing plate and are welded to the ring, while transverse cross-members extend across the sealing plate and are welded to the reinforcing members. The calandria may be removed from the reactor while attached to the ring member to provide ready access to the reactor internals.

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O'Hara Township, PA, United States of America

James A Drake