Westinghouse Electric Corporation

Franklin D Obermeyer

Luciano Veronesi

Edmund E DeMario

Ronald J Hopkins

John T Land

Robert T Berringer

George Bieberbach

James R Chrise

Craig H Popalis

Willis B Middlebrooks

Richard R Cruz

Control rod guide tube adapted to reduce vibration of a plurality of control rods disposed therein. The guide tube comprises an elongate housing surrounding the control rods, the housing having an opening at an end thereof for receiving a flowing fluid therethrough. The fluid has a velocity component acting transversely to the control rods sufficient to induce vibration of the control rods. However, the housing of the present invention has an intermediate portion pierced by a plurality of apertures for exit of the fluid from the housing to reduce the velocity of the fluid acting transversely to the control rods in order to reduce vibration of the control rods. As control rod vibration is reduced, control rod wear is mitigated.

Control rod guide tube

Vibration dampener for dampening vibration of a tubular member, such as an instrumentation tube of the type found in nuclear reactor pressure vessels. The instrumentation tube is received in an outer tubular member, such as a guide thimble tube. The vibration dampener comprises an annular sleeve which is attachable to the inside surface of the guide thimble tube and which is sized to surround the instrumentation tube. Dimples are attached to the interior wall of the sleeve for radially supporting the instrumentation tube. The wall of the sleeve has a flexible spring member, which is formed from the wall, disposed opposite the dimples for biasing the instrumentation tube into abutment with the dimples. Flow-induced vibration of the instrumentation tube will cause it to move out of contact with the dimples and further engage the spring member, which will flex a predetermined amount and exert a reactive force against the instrumentation tube to restrain its movement. The amount by which the spring member will flex is less than the unrestrained amplitude of vibration of the instrumentation tube. The reactive force exerted against the instrumentation tube will be sufficient to return it to its original axial position within the thimble tube. In this manner, vibration of the instrumentation tube is dampened so that in-core physics measurements are accurate and so that the instrumentation tube will not wear against the inside surface of the guide thimble tube.

Vibration dampener for dampening vibration of a tubular member

Segmented instrumentation tube including a locking sleeve for interlocking the segments of the instrumentation tube, so that the threaded ends of the instrumentation tube do not unthread when subjected to vibration, such an instrumentation tube being suitable for use in a nuclear reactor pressure vessel. The instrumentation tube has a first member having a threaded end portion that has a plurality of first holes circumferentially around the outside surface thereof. The instrumentation tube also has a second member having a threaded end portion that has a plurality of second holes circumferentially around the outside surface thereof. The threads of the second member are caused to threadably engage the threads of the first member for defining a threaded joint therebetween. A sleeve having an inside surface surrounds the end portion of the first member and the end portion of the second member and thus surrounds the threaded joint. The sleeve includes a plurality of first projections and second projections that outwardly extend from the inside surface to engage the first holes and the second holes, respectively. The outside surface of the sleeve is crimped or swaged at the locations of the first projections and second projections such that the first projections and the second projections engage their respective holes. In this manner, independent rotation of the first member with respect to the second member is prevented, so that the instrumentation tube will not unthread at its threaded joint.

Segmented instrumentation tube including a locking sleeve for

A closing device for removably securing and sealing engaging a closure around an opening in a transportation cask for radioactive materials is disclosed herein. The closing device comprises a plurality of shear key assemblies uniformly spaced around the outer portion of the closure, each of which includes a shear key having an elongated bolt portion movably mounted in the closure, as well as a latch portion connected to one end of the bolt portion that is insertable into and retractable out of a slot located in the edge of the cask that defines the cask opening. The latch portion is beveled so as to wedgingly engage the slot when inserted therein in order to apply a sealing pressure around the outer edge of the closure. The width of the latch portion of the key is substantially larger than the bolt portion, thereby giving the shear key a T-shaped profile. The broad width of the bolt portion allows the shear key to more uniformly distribute a sealing pressure around the closure. The closing device also includes either a single or multiple drive mechanisms for forcing the latch portions of the shear keys into and out of the slots in the cask. The single drive mechanism is extremely rapid in operation and advantageously applies the same amount of closing force to each shear key simultaneously, while the use of multiple drive mechanisms affords more uniform sealing pressure around the closure edge and more effective radiation shielding properties to the closure.

Latching device for securing a closure to a cask for transporting

A support pin system which is a non-welded system for fastening a first structural member, such as a nuclear reactor control rod guide tube flange, to a second structural member, such as nuclear reactor upper core plate, includes a support pin and nut. A first pin portion passes through the first member and has a threaded section which mates with the nut. A second pin portion has a solid body section and a split-leaf base section which biasingly engages a bore in the second member. The solid body section is accommodated by a close clearance fit. The split-leaf base section has an intermediate diameter which is less than the diameter of the solid body section. Thus, loads applied transversely to the system are reacted substantially in pure shear through the solid body section. The nut may be a locking nut having a crimpable cylindrical section integrally connected to an internally threaded section. The crimpable section is crimped to engage recesses provided in the pin whereby relative rotation therebetween is positively prevented. A locking nut retainer may optionally be provided for positively retaining the nut in position around the support pin which has a crimpable split cylindrical wall portion and an axial slot, and tabs. The retainer is compressed for insertion into a bore in a structural member, the bore having an annular recess for accommodating the tabs whereby the retainer is positively retained in the structural member and the wall portion is crimped to engage the nut.

Support pin system and locking nut retainer

A nuclear reactor including, in the upper internals, a guide structure capable of effectively accommodating and guiding without binding the large number of neutron-absorber rods included in modern reactors of improved efficiency. The neutron-absorber rods include control rods, gray rods, and water-displacement rods. All rods are suspended in clusters from spiders or vanes. The upper internals of the reactor includes cruciform guides for the control-rod and gray-rod clusters. Each of these guides is composed of a plurality of vertical guide sections of transverse cruciform cross section. Plates extending throughout the cross-section of the reactor are supported between each pair of successive guide sections. The plates are perforated, the perforations in each plate being patterned to pass the water-displacement rod clusters. The plates are oriented so that the patterned perforations are aligned to serve as guides for the water-displacement rod clusters. The plates are of very large diameter and, as perforated, would not be self-supporting unless they were very thick. To overcome this drawback, each plate is formed of separate plate sections which are, when assembled nested together, like the parts of a 'jig-saw puzzle'.

Nuclear reactor

A liquid-cooled nuclear reactor including fuel assemblies mounted within a reactor vessel having linearly movable control rods passing through control rod guide tubes into respective aligned fuel assemblies. Reactor coolant circulates through the assemblies, guide tubes and other vessel internals structures located above the assemblies and is discharged through an outlet nozzle positioned above the elevation of primary flow openings in the guide tube walls. The guide tube includes internal horizontal supports and a length limited continuous control rod guide which, in conjunction with the flow openings, alleviate detrimental coolant cross flows and frictional restraints imposed upon the control rods.

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Pensacola, FL, United States of America

Franklin D Obermeyer