Abstract: A vacuum transfer apparatus for use in en masse vacuum gripping nuclear fuel pellets includes an enclosure defining a vacuum chamber and having an open bottom, a rigid support gridwork spanning and attached to the enclosure open bottom, and a perforated mat attached to the gridwork along a side opposite from the enclosure. The mat is composed of resiliently flexible material and has a matrix of spaced apart holes of a cross-sectional size substantially smaller than the diameter of the pellets. The support gridwork defines a plurality of passages of a cross-sectional size substantially larger than that of the holes in the mat. The gridwork passages provide the sole path for communicating a vacuum from the enclosure chamber to the mat holes for vacuum gripping and holding the pellets at their upper end surfaces against the mat. A perforated tray is employed with the vacuum transfer apparatus for supporting the fuel pellets.

Abstract: A gripper mechanism for sampling nuclear fuel pellets at a predetermined depth in a stack of pellets includes a housing and gripping fingers movably mounted to the housing. The fingers are preferably three relatively thin, arcuate-shaped, blade-like fingers angularly displaced from one another for grasping the pellet at spaced locations about its circumference. The fingers have lower facing surfaces which are brought adjacent to one another for engaging and grasping a pellet when the fingers are moved toward their closed position and retracted remote from one another for disengaging and releasing the pellet when the fingers are moved toward their opened position.

Abstract: A nuclear reactor fuel rod end plug (100) is adapted to be welded within each end of a nuclear reactor fuel rod cladding tube, especially by means of laser beam welding techniques, although TIG welding techniques may also be employed, wherein an annular groove (126) is defined about the external periphery of the end plug (100) so as to extend radially inwardly of the long land region (118) of the plug (100) within the vicinity of the juncture of the land surface (118) and the shoulder portion (120) at which location the girth weld between the end plug (100) and the cladding tubing will be defined.

Abstract: A gripper mechanism for sampling nuclear fuel pellets at a predetermined depth in a stack of pellets includes a housing and gripping fingers movably mounted to the housing. The fingers are preferably three relatively thin, arcuate-shaped, blade-like fingers angularly displaced from one another for grasping the pellet at spaced locations about its circumference. The fingers have lower facing surfaces which are brought adjacent to one another for engaging and grasping a pellet when the fingers are moved toward their closed position and retracted remote from one another for disengaging and releasing the pellet when the fingers are moved toward their opened position.

Abstract: A self-aligning fixture for use in a high temperature top-loading furnance includes multiple stacked trays to optimize load placement and capacity and to minimize fixture heat absorption. The fixture is manipulated by a handling tool to insert, position, and withdraw the fixture without obscuring the chamber and includes self-aligning blackbody radiators insertable by a handling tool into the optical path of an optical pyrometer and onto a selected tray for temperature monitoring of the load therein. A calibration blackbody radiator allows independent pyrometer verification of an inserted thermocouple.

Abstract: A system for loading friable nuclear fuel pellets into sintering boats from a pellet press which ejects newly made pellets. A chute receives the ejected pellets and discharges them into an upright bowl at a location towards the top of the bowl near its inner surface with a tangential horizontal component of velocity. The bowl, which has an open smaller diameter bottom, is rotated such that the bowl near the pellet-discharge location has a velocity which generally matches the magnitude and direction of the horizontal component of the velocity of the pellets at the discharge location. A conveyor moves a line of adjacently positioned boats horizontally beneath the bottom of the bowl. A flexible strap which cushions the pellets as they enter a sintering boat also acts as a seal between boats.

Abstract: A tube straightness checking apparatus includes a gauging mechanism disposed along a linear path and being operable to check the straightness of the tube as it is moved along the path past the mechanism. The gauging mechanism is operable to detect deviation of the tube from an imaginary centerline which is generally coincident with the linear path. The apparatus also includes linear hearing sets which guide a tube along the generally linear path past the gauging mechanism. Two embodiments of the gauging mechanism are disclosed. In the preferred embodiment, the gauging mechanism includes a gauge plate with a circular gauging orifice defined therein through which the tube passes as it is moved along the linear path. The gauge plate is electrically conductive and forms part of an electric circuit which is operable to provide an indication of an out-of-straightness condition upon the tube contacting the gauge plate as the tube moves along the linear path through the gauging orifice of the plate.

Abstract: An automated fuel rod production system includes a radioactive powder fabrication and processing stage, a pellet fabrication stage, a pellet processing stage, a tube preparation stage and a fuel rod fabrication and inspection stage, all of which provide a continuous (paced) mode of operation from the conversion of a radioactive gas to powder, through the fabrication of the powder into pellets, to completion of the assembly of the fuel rods. Extra capacity is designed into the system at critical points in the powder processing and pellet fabrication and processing stages to facilitate the continuous, paced mode of operation.

Abstract: A nuclear fuel pellet unloading apparatus includes a boat clamping and inverting mechanism which receives a boat loaded with pellets, clamps the boat and pivots it along an arcuate path adjacent a pellet transfer shroud from an initial upright position to a generally inverted position and then back to the upright position. As the loaded boat is pivoted, it progressively inverts next to an arcuate wall portion of the shroud which coacts to contain individual pellets as they begin to empty from the boat. The emptied pellets flow down the shroud to the next station. By the time the boat reaches its inverted position all of the pellets have emptied from the boat. The unloading apparatus also includes a pair of pneumatic cylinders which are selectively actuated for respectively delivering a loaded boat from a boat conveyor to the inverting mechanism and ejecting an empty boat from the inverting mechanism back to the boat conveyor.

Abstract: An improved end plug is provided for a nuclear fuel rod assembly. The end plug is of an integral construction having an upper shoulder portion which abuts the top edge of a fuel tube and a circular body portion adapted to be inserted into the end of the fuel tube in a force fitting relationship. A flat is provided on the lower body portion so as to define a gap between the lower body portion and the inner wall of the fuel tube upon partial insertion of the plug into the tube, the gap providing an orifice for introducing an inert-gas under pressure into the tube. Upon total insertion of the lower body portion of the plug into the tube, the gap is eliminated and metal-to-metal contact is made between the lower body portion of the plug and the end of the fuel tube for sealing the pressurized gas and a nuclear fuel within the fuel tube.

Abstract: Apparatus and method for directing a controlled number of laser pulses onto a work piece to be machined. More specifically, the laser machining apparatus includes an excitable laser and an excitation lamp for continuously exciting the laser to emit a sequence of laser pulses. The application of the laser pulses to the work piece is controlled by an inner-cavity shutter that is opened to permit a precise number of pulses to be directed onto the work piece. The frequency (REP RATE) and pulse width of the laser pulses are controlled by the excitation lamp and, in turn, are set to create a progressive weld of significant depth and structural integrity. In particular there is provided control means for counting the number of laser pulses applied to a machining site of the work piece, whereby a known controllable quantity of energy is imparted to each site.