Westinghouse Electric Corporation

David V Lambert

Mark P Goldenfield

Theodore W Nylund

John T DiGrande

Joseph V Cioffi

Damon E Haley, Jr

John W Byers

Hassan J Ahmed

Thomas B Huggins

Robert E Shannon

Elwyn Roberts

Gary W Cuba

Kendell L McDill

Robert D Isaacson

Nuclear fuel rod tubes of zirconium alloy are heat treated in an induction furnace to produce a protective oxide coating two to fifteen microns in thickness. The furnace is only slightly larger than the tubes and receives the endmost eight inches of the tube. The furnace is controllable in zones along the tube. To calibrate the furnace to produce the desired temperature profile, typically a flat profile at a temperature between 650.degree. and 750.degree. C..+-.1.5.degree. C., a temperature calibration probe is provided with spaced thermocouples for sensing the temperature developed in the probe at each of the zones when heated. The probe is made of inconel 600 stainless or the like, and is dimensioned and shaped to correspond closely to the dimensions of the fuel rod tubes, including having a closed chamfered end. At the opposite end the probe protrudes from the furnace, where the thermocouple leads are terminated. The leads pass through a potting compound in the probe, such as magnesium oxide. Whereas the probe conductive structures are substantially identical to the tube, the probe responds to the electromagnetic field in the induction furnace substantially the same as does the end of the tube, permitting calibration of the induction furnace zones for a desired temperature profile, e.g., flat along the length of the tube, notwithstanding differences in induced currents that would otherwise occur due to the end of the tube or the adjacent tube material.

Calibration fixture for induction furnace

An automated fuel assembly loader, capable of patterned loading, moves nuclear fuel rods in a loading direction between a fuel rod skeleton defining an array of receptacles for the fuel rods, and a fuel rod magazine supplying or receiving the fuel rods. A table supports the fuel rod skeleton at a loading position. A movable carriage having a line of individual fuel rod engaging devices moves a subset of fuel rods along the line forward in the loading direction. The rods are selected via a pattern stored in a controller. Selection devices such as pneumatic clamps mechanically couple the selected engaging devices to the carriage for movement while others are left behind. A ball screw carriage drive arrangement moves the carriage parallel to the loading direction and a jack screw positioning drive displaces the carriage perpendicular to the line of fuel rods. A controller is coupled to the carriage drive and to the selection devices, and stores data defining a preset pattern of receptacles in the array, operating the selection devices for actuating a group of engaging devices corresponding to the pattern. The controller also controls displacement speed, permitting patterned loading of the skeleton, for example to obtain a particular pattern of fuel rod enrichments, the controller moving line by line through an array of fuel rod receptacles in the skeleton.

Automatic fuel assembly loader

An apparatus for setting an arc gap between a weld electrode and a workpiece includes a control arrangement and a direct current stepping motor operated in a forward mode by the control arrangement to move the weld electrode toward and away from the workpiece to respectively advance and retract the electrode into and from physical contact with the workpiece. The apparatus also includes an electrical circuit connected to the weld electrode and the workpiece for defining an electrical path to supply electrical energy sufficient to generate a welding arc between the electrode and workpiece, and an electrical continuity sensor connected to the electrical path and being operable for sensing the opening and closing of electrical continuity of the electrical path and for generating a trigger signal to the control arrangement in response to sensing the closing of continuity of the electrical path by the electrode making physical contact with the workpiece. The control arrangement in response to receipt of the trigger signal from the continuity sensor causes the electric motor to operate in a reverse mode to retract the electrode from physical contact with the workpiece to a welding position located a predetermined distance from the workpiece. A vacuum relay is operable to isolate the continuity sensor from the electrical path in response to receipt of an output signal generated by the control arrangement when the electrode reaches the welding position.

Weld electrode-to-workpiece arc gap setting apparatus and method

An inspection system has a pellet diameter inspecting station and an apparatus for transferring pellets past the station. The apparatus includes a stationary support track for aligning and guiding pellets in a row along a linear path, and a transfer mechanism operable through forward and reverse strokes. The transfer mechanism has first and second grippers actuatable between pellet gripping and releasing positions and operable to grip respective rearmost pellets in a first row of pellets to be advanced past the inspecting station and in a second row of pellets previously advanced past the inspecting station. The transfer mechanism is operable to move from an initial position through the forward stroke to advance the pellets at a constant velocity along the linear path. The transfer mechanism actuates the second gripper from its releasing to gripping position before actuating the first gripper from its releasing to gripping position and starts movement from the initial position along the forward stroke before the first gripper is so actuated such that a gap is formed between the previously advanced row of pellets and the row of pellets to be advanced so as to prevent buckling of pellets in the latter row. The transfer mechanism is also operable to actuate the grippers to release the pellets and move through the return stroke relative to the released pellets back to the initial position.

Pellet transfer apparatus and method

Apparatus for loading fuel rods in a desired enrichment pattern includes a carrousel, an elongated fuel rod storage magazine, and a fuel rod verify and feed workstation and a magazine holder and indexing mechanism disposed between the carrousel and the magazine. The carrousel has a plurality of gondolas movable mounted thereon for stocking fuel rods of known enrichments. The magazine defines a matrix of elongated slots open at their forward ends for receiving fuel rods. The workstation defines a fuel rod feed path extending between the carrousel and the magazine and is adapted to receive successively one at a time along the feed path at its upstream end fuel rods from selected ones of the carrousel gondolas. The workstation includes an optical scanning and reading unit located along the feed path for verifying the identity of the fuel rods successively one at a time and a fuel rod feeding mechanism for successively feeding one at a time along the feed path the verified fuel rods into selected ones of the slots in the magazine. The magazine holder and indexing mechanism movably supports the magazine and is actuatable for moving the magazine along X-Y axes to successively align one at a time selected one of its slots with the feed path for loading in the magazine the successive fuel rods in a desired enrichment pattern.

Automated nuclear fuel rod pattern loading system

An pellet diameter inspection system has a laser scanning apparatus for measuring and detecting the outside diameter of the pellets and an apparatus for transferring pellets past the laser scanning apparatus. A stationary support track aligns and guides pellets in a row along a linear path past the laser scanning apparatus with the pellets being advances along the path by the transfer apparatus operating through forward and reverse strokes. The laser scanning apparatus includes a laser beam light source and receiver disposed on opposite sides of the linear path in a non-orthogonal orientation to the common axis of the aligned pellets and operable for respectively emitting and receiving a laser beam directed across the pellets along a directional path extending in a non-orthogonal orientation to common axis of the pellets which will eliminate detection of adjacent ends of the pellets in the row.

Pellet diameter measurement apparatus and method detecting

In a method for nondestructive measurement of the heat affected zone of an identification code on a nuclear fuel rod tube, the change in impedance of an electromagnetic coil produced by a portion of the tube to be etched with a bar code is measured before and after the etching of the bar code is performed by use of laser power. The impedance change in the coil produced by the bar code-bearing tube portion is compared with the impedance change produced in the coil by the same tube portion before the bar code is generated thereon to determine whether a maximum allowed depth of the heat affected zone of the tube portion has been exceeded.

Method for nondestructive measurement of heat affected zone of

In a nuclear fuel rod identification system, a bar code etched directly on a surface of a nuclear fuel rod is read by first positioning the fuel rod such that its surface portion having the bar code etched directly thereon, such as by a laser, is disposed adjacent to a light diffuser surface and between such surface and a light reader. Next, a beam of laser light is directed on the bar code on fuel rod surface portion such that the light is reflected therefrom onto the light diffuser surface. Then, the light reflected from the bar code via the light diffuser surface is received and read by the light reader. The light diffuser surface is disposed at about thirty degrees relative to the path of the beam of light directed to the fuel surface portion such that only about twenty-five percent of the light is reflected by the diffuser surface back to the light reader.

Method and apparatus for reading lased bar codes on shiny-finished fuel

Apparatus for loading fuel rods in a desired enrichment pattern includes a carrousel, an elongated fuel rod storage magazine, and a fuel rod verify and feed workstation and a magazine holder and indexing mechanism disposed between the carrousel and the magazine. The carrousel has a plurality of gondolas movable mounted thereon for stocking fuel rods of known enrichments. The magazine defines a matrix of elongated slots open at their forward ends for receiving fuel rods. The workstation defines a fuel rod feed path extending between the carrousel and the magazine and is adapted to receive successively one at a time along the feed path at its upstream end fuel rods from selected ones of the carrousel gondolas. The workstation includes an optical scanning and reading unit located along the feed path for verifying the identity of the fuel rods successively one at a time and a fuel rod feeding mechanism for successively feeding one at a time along the feed path the verified fuel rods into selected ones of the slots in the magazine. The magazine holder and indexing mechanism movably supports the magazine and is actuatable for moving the magazine along X-Y axes to successively align one at a time selected ones of its slots with the feed path for loading in the magazine the successive fuel rods in a desired enrichment pattern.

In a nuclear fuel rod identification system, indicia is provided on a nuclear fuel rod in two stages. In the first stage, by use of a laser beam a bar code is applied directly on the fuel rod cladding tube prior to loading it with nuclear fuel and attaching plugs to opposite ends thereof to provide an assembled fuel rod. In the second stage, after loading nuclear fuel into and attaching end plugs to opposite ends of the fuel rod cladding tube with the applied bar code to provide an assembled fuel rod, by use of a laser beam, identification and enrichment symbologies are applied respectively to the side and end of one of the end plugs of the assembled fuel rod.

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St. Matthews, SC, United States of America

David V Lambert