JAMES A DRAKE
Engineers in Pittsburgh, PA

6358000, Mar 19, 2002

Jun 6, 2000

09/587763

Luciano Veronesi - Pittsburgh PA
James A. Drake - Pittsburgh PA

Westinghouse Electric Company LLC - Pittsburgh PA

F01D 2526

415134, 29888021

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.

6328541, Dec 11, 2001

Mar 7, 2000

9/520860

Luciano Veronesi - Pittsburgh PA
James A. Drake - Pittsburgh PA

Westinghouse Electric Company LLC - Pittsburgh PA

F04B 1700, F04B 3500

417373

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.