General Electric Company

James E Cearley

Robert C Dixon

Paul Van Diemen

Gerald M Gordon

Kenneth R Izzo

Edwin D Sayre

Yuen H Kong

John Geddes Erbes

James Edward Charnley

Thomas G Dunlap

James R Punches

Jaime A Zuloaga, Jr

John C Carruth

Louis L Aiello

Harold L Nelson

William G Jameson, Jr

Carl R Mefford

David F Holland

David T Hurt

Stephanie S Spencer

Frederick J Moody

David A Salmon

Matthew G Garbett

An assembly for servicing a cruciform control blade includes a carriage having first and second crossarms each containing a generally U-shaped slot for receiving the top of the control blade. The first crossarm includes a clamping actuator to rigidly clamp the carriage to the blade top. The second crossarm includes a tool positionable adjacent to a roller aperture in a selected one of the four panels of the control blade. The tool is positioned on the second crossarm at a predetermined depth, and at a predetermined lateral span from the first crossarm so that upon mounting of the carriage on the blade top and actuation of the clamping actuator, the tool is vertically and laterally aligned with a center of the panel roller aperture. In one embodiment, the tool is effective to sever the roller from the panel aperture without damaging the panel, and in another embodiment the tool is effective for installing a replacement spacer pad in the aperture.

Control blade servicing assembly

A spacer pad for a nuclear control rod includes first and second halves each including a head and a shank. The shanks are configured for joining together the pad first and second halves, and the shanks are independently locked together for preventing the disassembly thereof. In an exemplary embodiment, the first and second shanks are threadingly joined together, and then independently locked together using a complementary hook and ledge respectively supported by the pad halves which allows assembly together of the pad halves but prevents disassembly thereof.

Control rod spacer pad

An apparatus and method are provided for servicing an irradiated nuclear control rod underwater in a reactor building servicing pool. A turntable containing a plurality of spaced apart tools is positioned adjacent to the control rod. A first tool aligns the turntable relative to the radioactive roller mounted to the control rod by a radioactive pin therethrough. The turntable is indexable to position a second tool adjacent to the radioactive roller and pin, with the second tool being effective for freeing the radioactive pin from the control rod. The turntable is indexable for positioning a third tool adjacent to the radioactive roller and pin for removing the radioactive pin and the roller from the control rod. In further embodiments of the invention the turntable is further indexable for positioning a fourth tool adjacent to the control rod for reaming the pin aperture through which the radioactive pin was mounted. The turntable further includes a fifth tool which is indexable into position adjacent to the control rod for inserting a replacement roller and replacement pin therein. The replacement pin is secured to the control rod by a sixth tool supported on the turntable which is also indexable into position.

Control rod servicing apparatus and method

Flux-trap control rod flow diverters comprising a series of tabs formed along the length of one side of a hafnium neutron absorber tube, and bent inwards towards the opposing side so as to allow water in one side of the tube, and simultaneously divert internal water out of corresponding openings formed in the opposing side of the tube. In this way the internal water does not stay inside the control rod long enough to boil, and the water's effectiveness as a neutron moderator is assured.

Control rod flow diverters

An apparatus and process for control rod assembly and construction for a nuclear reactor is disclosed wherein the control rod is of cruciform configuration having a plurality of and preferably four flat planar members. Each planar member is made up with an assembly of square cross sectioned tubular members. Each square cross sectioned tubular member includes a defined cylindrical center and a constant thickness surrounding tubular metallic shell to provide the contained neutron absorbing materials in a cylindrically shaped pressure vessel. The constant thickness surrounding tubular shell constituting the cylindrical shaped pressure vessel has four corner sections added to generate a modified square exterior profile. These added four corner sections comprise an addition to the tubular side wall thickness of the shell. Appropriate chamfers and rounding are provided to the square profile to impart both stress relief and convenient points for automated welding between side-by-side square sections. The square cross sectioned tubular members when welded together extend axially and longitudinally the length of the control rod in the direction of control rod movement and fluid flow. The square cross sectioned tubular members are filled with a neutron absorbing material, plugged at both ends, and fastened by welding in side-by-side relation to form the planar control rod members of the required cruciform shape. These square cross sectioned tubular members as welded in side-by-side relation are in integral portion of the longitudinal support structure of the control rod and fasten and interconnect the handle at the top of the control rod and a conventional velocity limiting device at the bottom of the control rod. The fastening of the handles and velocity limiting device at the respective top and bottom provides a secondary and supplemental seal to primary plugs containing the neutron absorbing material. If needed for enhanced life, provision is made for the incorporation of a hafnium plate in a rectangular sectioned tube adjacent the handle at upper end of the control rod, this tip being variable in length dependent upon individual control rod requirements. Thus square sectioned tubular members form an improved poison containing cylindrical volume for providing resultant improved control rod worth and increased in service life time in moderating and shutting down nuclear reactions. Consequently, the disclosed construction can be used both for conventional control rods as well as for control rod configured for control cell locations.

Control rod

An apparatus and process for control rod assembly and construction for a nuclear reactor is disclosed wherein the control rod is of cruciform configuration having a plurality of and preferably four flat planar members. Each planar member is made up with an assembly of square cross sectioned tubular members. Each square cross sectioned tubular member includes a defined cylindrical center and a constant thickness surrounding tubular metallic shell to provide the contained neutron absorbing materials in a cylindrically shaped pressure vessel. The constant thickness surrounding tubular shell constituting the cylindrical shaped pressure vessel has four corner sections added to generate a modified square exterior profile. These added four corner sections comprise an addition to the tubular side wall thickness of the shell. Appropriate chamfers and rounding are provided to the square profile to impart both stress relief and convenient points for automated welding between side-by-side square sections. The square cross sectioned tubular members when welded together extend axially and longitudinally the length of the control rod in the direction of control rod movement and fluid flow. The square cross sectioned tubular members are filled with a neutron absorbing material, plugged at both ends, and fastened by welding in side-by-side relation to form the planar control rod members of the required cruciform shape. These square cross sectioned tubular members as welded in side-by-side relation are an integral portion of the longitudinal support structure of the control rod and fasten and interconnect the handle at the top of the control rod and a conventional velocity limiting device at the bottom of the control rod. The fastening of the handles and velocity limiting device at the respective top and bottom provides a secondary and supplemental seal to primary plugs containing the neutron absorbing material. If needed for enhanced life, provision is made for the incorporation of a hafnium plate in a rectangular sectioned tube adjacent the handle at upper end of the control rod, this tip being variable in length dependent upon individual control rod requirements. Thus square sectioned tubular members form an improved poison containing cylindrical volume for providing resultant improved control rod worth and increased in service life time in moderating and shutting down nuclear reactions. Consequently, the disclosed construction can be used both for conventional control rods as well as for control rod configured for control cell locations.

A neutron absorbing control device for service in nuclear reactors utilizing fissionable fuel. The control device includes hafnium metal as the neutron absorbing material which is employed in a unique structure which maximizes the advantages of hafnium while minimizing its disadvantages as well as providing other benefits.

Hafnium control rod for nuclear reactors

In a control rod construction for moderating and controlling a reaction of a nuclear reactor, a control rod structure is disclosed in which hafnium is welded to stainless steel. Typically, the control rod is confined for movement axially along its length into and out of the reactor. The hafnium is surrounded in the control rod structure by a sheath of stainless steel to inhibit movement relative to the control rod structure other than in the axial direction of control rod movement. The hafnium is friction welded to the stainless steel of the control rod so as to stress the weld in either tension or compression due to dynamic loading occurring from control rod movement. The stainless steel to which the hafnium is welded is in turn conventionally welded or mechanically connected to the remaining steel components of the control rod. There results a secure control rod structure having welded hafnium that can withstand the dynamic loadings of fast insertion of control rods such as those loadings which commonly occur under rapid control rod acceleration and deceleration due to SCRAM of a reactor.

Hafnium stainless steel absorber rod for control rod

A control rod for a nuclear reactor wherein plates of neutron absorbing material (e.g. hafnium) are used in the upper portion thereof and tubes containing a different neutron absorbing material (e.g. boron) are positioned beneath the plates. To relieve the tubes of the weight of the plates, the plates are attached to support members of the control rod frame, to prevent or reduce the area of a gap between the plates and the tubes, joints therebetween are provided.

Nuclear reactor control rod

A velocity limiting device providing greater resistance to motion through a fluid in one direction than in the opposite direction. The device includes a toroidally shaped control member having a smooth generally conical surface on one side for low resistance movement through the fluid in the one direction. On its opposite side the control member is formed with at least one groove providing a concave surface spaced from which is an arrangement of vanes forming a jet for directing a stream of fluid into the groove upon movement in the opposite direction whereby the resultant increase in fluid turbulence increases resistance to rapid movement in this opposite direction.

Control rod velocity limiter

In a nuclear fuel assembly having a coolant conducting or water tube which also retains the spacers in axial position, the fuel rods experience greater axial growth with exposure than the water tube creating a risk that the water tube might become disengaged from the supporting tie plates. An arrangement for preventing such disengagement is described including lengthened end plug shanks for the water tube, a protective boss surrounding the lower end plug shank to protect it from flow induced vibration, a conical seat for the lower end plug and an arrangement for limiting upward movement of the water tube.

Growing community of inventors

San Jose, CA, United States of America

James E Cearley