General Electric Company

Frank Ortega

Robert S Tsukida

Balasubramanian S Kowdley

Edward W Saxon

Thomas W White

Thomas A Lewis

Henry Peter Offer

Gerald A Deaver

Bettadapur N Sridhar

Hsueh-Wen Na Pao

Douglas K Ethridge

Thomas R Eckmann

John Geddes Erbes

James H Terhune

Robert W Whitling

Barry Hal Koepke

David L Richardson

Jeffrey L Thompson

David L Faulstich

Fred Charles Nopwaskey

David Wesley Sandusky

James F Kasik

Terry Lynn Chapman

Ahdee Quan Chan

Mark William Broaddus

Harry I Russell

Christopher J Miller

Robert K Lovell

John Edward Maslakowski

Vincent R Cantacessi

Andrew S Wong

Herbert B Dela Rosa

Dale M Oliver

Edward J Pulpan

Brian Charles Duckering

Paul Debenedetto

Systems and methods for refueling a nuclear reactor that has a reactor core in a reactor pool having a plurality of elongated reactor core components, a fuel pool for storing core components, and a transfer channel connecting the fuel pool to the reactor pool. The method includes retrieving a replacement core component from the fuel pool, and securing the replacement core component in a first compartment of a handover assembly in a vertical position. The method also includes retrieving a spent core component from the reactor core, and securing the spent core component in a second compartment of the handover assembly in a vertical position. The replacement core component is retrieved from the first compartment and installed into the reactor core. The spent core component is retrieved from the second compartment and stored in a storage rack in the fuel pool.

Handoff methods and assemblies for refueling a nuclear reactor

A surface conditioning scheduling process is used to mitigate susceptibility to crack initiation or crack growth in a boiling water nuclear reactor using a plurality of working crews. A plurality of working zones are defined in an annulus region of a reactor vessel flange, and a plurality working zones are defined in a core region of the reactor vessel. One of the working crews is positioned in each of the annulus region working zones, and one of the working crews is positioned in each of the core region working zones. The working crews perform surface conditioning in areas of the reactor vessel accessible from their respective working zones such that the surface conditioning process can be completed in no more than thirty days.

Renew process implementation for reactor bottom head

An electrical discharge machining (EDM) tool and method for removing tack welds on a component in a reactor pressure vessel are disclosed. The tool may include a motor, a housing which engages the component having tack welds, an electrode, positioned in the housing, a first plate, and a second plate attached to the electrode. The second plate actuates to align the electrode to the tack weld, and the electrode is discharged to remove the tack welds from the component.

Method and apparatus for removing tack welds on reactor vessel components in a nuclear reactor

A tool assembly provides for brushing circumferential welds in a restrictive access area between a cylindrical inner member and a cylindrical outer member such as the shroud and vessel in a nuclear reactor. The tool assembly includes a circumferential plate sized larger than an outside diameter of the inner member and smaller than an inside diameter of the outer member. At least one renew brush is coupled with the circumferential plate, and a motor is coupled with the renew brush that rotates the renew brush. A driving assembly mounted between the inner member and the outer member engages the circumferential plate and circumferentially drives the circumferential plate in the restrictive access area.

Tool for brushing circumferential welds in restricted access areas

Welding repairs are performed in an underwater environment adjacent the bottom head of the nuclear reactor vessel. To provide a dry welding environment, segments of a lower caisson are passed through the core plate holes and assembled along the interior surface of the bottom head. The assembled segments are held down by brackets and sealed to one another and to the bottom head by a water curable polymer. An upper caisson is passed through the core plate hole to sealingly engage the lower caisson. The caissons are pumped dry and welding equipment is passed through the caissons to effect weld repairs about the stub tube or along the bottom head cladding.

Method for providing a dry environment for underwater repair of the reactor bottom head using a segmented caisson

A lower housing having a lower chamber and a welding opening is fixed about an underwater weld site. The lower housing includes an upper opening, the lower housing being filled with water upon installation. A transport housing containing a welding unit in a dry state is lowered such that a bottom opening, closed by a closure element, registers with an upper opening of the lower chamber. Upon clamping the housings together, the lower chamber is at least partially evacuated. The closure element is then moved to an open position and the welding unit is lowered into the evacuated lower chamber to weld a patch to the vessel wall to overlay the damaged area.

Apparatus and methods for underwater welding

A seal plate for repairing damaged areas in a pressure vessel cladding includes a first side and an opposing second side and a sealing portion located on the second side, with the sealing portion circumscribing the seal plate. The seal plate also includes a seal lip extending from a periphery of the sealing portion and a cavity located in the second side, with the cavity circumscribed by the sealing portion. The seal plate further includes at least one purge port extending from the first side to the cavity. Each purge port is in fluid communication with the cavity.

Apparatus and method for repairing reactor vessel cladding using a seal plate

An electric discharge machining sampling apparatus for obtaining samples from a surface of metal components provided. In an exemplary embodiment, the sampling apparatus is operable underwater and includes a base plate and an electrode assembly movably coupled to the base plate. The electrode assembly includes an electric discharge electrode and an electrode holder with the electrode including at least one bore extending therethrough. The sampling apparatus also includes a particle collection assembly operatively coupled to the electrode. Each electrode bore is in flow communication with the particle collection assembly.

Noble metal in-situ sampling method and apparatus

A method and an apparatus for ultrasonically inspecting the welds which attach the differential pressure and liquid poison nozzles to the bottom head of the reactor pressure vessel in a boiling water reactor. The scanning apparatus is seated on the upper taper of the nozzle outer tube and incorporates a stationary frame having a cutaway section which allows installation from the side. The apparatus has vertical and circumferential positioning mechanisms which are operated remotely to scan an ultrasonic transducer package over the circumferential welds and heat-affected zones thereof. The rotating frame has a transducer carriage mounted thereon which is vertically displaceable relative to the rotating frame. The vertical and angular motion motors can be controlled together to provide the desired path for the ultrasonic transducer around the stub tube. The tool also includes a vessel contour follower which follows the contour of the inclined surfaces of the reactor pressure vessel bottom head. The vessel contour follower is linked to the ultrasonic transducer to ensure that the transducer follows the contour of the weld, in position and angle.

Method and apparatus for remote ultrasonic inspection of nozzles in

An auxiliary wedge apparatus configured to couple to the restrainer bracket of a jet pump assembly is described. In one embodiment, the auxiliary wedge apparatus includes a support block configured to couple to the restrainer bracket, and a wedge configured to slidingly couple to a wedge channel in the support block, and to engage the inlet mixer to restore a tight rigid fit-up of the jet pump components. The support block includes a wedge channel having tongues depending from the parallel sides of the channel and a hook shaped portion configured to receive the restrainer bracket. The support block also includes a lock screw to couple the support block to the restrainer bracket. The wedge includes grooves in the parallel sides of the wedge configured to slidingly engage the tongues extending in the wedge channel. The auxiliary wedge apparatus also includes a restraint arm depending from the support block configured to capture the existing set screw in the restrainer bracket to prevent the screw from completely unscrewing.

Jet pump auxiliary wedge

A core spray line assembly for a nuclear reactor is described. In one embodiment, the core spray line assembly includes first and second core spray lines. Each of the core spray lines is substantially located within the reactor pressure vessel and has first and second ends connected to the shroud The first and second core spray lines include an adjustable core spray header and first and second articulating vertical pipe connector. The adjustable core spray header and articulating pipe connectors facilitate fast and easy replacement of existing core spray lines with the present core spray lines.

Core spray line assembly

Methods and apparatus for maintaining a compression force in a reactor pressure vessel (RPV) of a nuclear reactor are described. In one embodiment of the apparatus, a spring assembly facilitates applying compression force on the shroud head. The spring assembly, in one embodiment, includes two trusses and two torsion bars. The torsion bars extend between the trusses and are connected at opposite ends to the trusses. Each truss includes a truss support member, a hooking element, and a torsion converter element. The truss support member is configured to rest on the shroud head flange. The hooking element is pivotally coupled to the truss support member, and includes a hook adjacent a guide rod. The torsion converter element is coupled to the hooking element, and is vertically movable with respect to the truss support member. The converter element has two ends, each end splined to one of the torsion bars so that vertical movement of the converter element drives, e.g., rotates, the torsion bars.

Methods and apparatus for applying a compressive force to a core shroud

An uncoupling tool has a two-module design: one module being a driver assembly for developing the uncoupling movement and the other module being a probe assembly for verifying the uncoupled condition. The probe assembly attaches to the threaded end of the piston tube with its probe extending inside the piston tube. The driver assembly attaches to the CRD ring flange. The probe assembly detects the ring magnet in the drive piston using analog position sensors which operate on the principle of the Hall effect and solid state circuitry. A top sensor provides a signal indicating that the control rod is in its 'full out' position; a bottom sensor provides a signal indicating that the control rod is uncoupled; and an intermediate sensor provides a signal indicating that the control rod is in a transition position between the 'full out' and uncoupled positions. The probe incorporates spacers which focus the magnetic flux onto the sensors. To uncouple the control rod, the probe assembly is lifted using a separate driver assembly.

Multistage control rod drive uncoupling tool

A method and a gage for testing uncoupling tools to ensure proper operation prior to use. The uncoupling tool gage simulates the actual conditions under which the uncoupling tool is expected to perform. The gage has a cylindrical guide for slidably receiving a magnet housing. The guide is supported such that it is concentric with respect to the probe of an uncoupling tool to be checked. The magnet housing is placed inside the cylindrical guide and then moved toward the bottom thereof. When the magnet moves into proximity with a switch in the uncoupling tool probe, an indicator lamp in the uncoupling tool illuminates. If the face of the magnet housing is within a range band on the outside of the guide when the indicator is illuminated, then the uncoupling tool is operating properly.

Control rod drive uncoupling tool gage

A tool for checking the length of a control rod drive measured from the top of the control rod drive flange to the end of the uncoupling rod. The tool is a GO--NO--GO gauge with tight tolerance. The top of the tool supports a gage which has an arm that pivots about an axis parallel to the tool axis. The arm has a stepped notch with a predetermined height equal to the length tolerance range (e.g., 0.0625 inch). The length is considered acceptable when the gage is rotated and the first edge of the stepped notch on the arm just clears the end of the uncoupling rod but the second edge stops the gage from pivoting any further. The length is not acceptable if the first edge of the stepped notch on the arm abuts the uncoupling rod, preventing the gage from pivoting any further, or if the gage misses the uncoupling rod entirely.

Growing community of inventors

San Jose, CA, United States of America

Frank Ortega