Abstract: Both a system and method are provided for laser welding the inner walls of conduits, such as the sleeves used to repair the heat exchanger tubes of nuclear steam generators. The system generally comprises an elongated tubular housing, a fiber-optic cable for conducting remotely generated laser light into the tubular housing, a beam deflection mechanism supported within the distal end of the tubular housing and including a rotating mirror for radially reflecting and focusing light received from the fiber-optic cable around the inner wall of the sleeve, and a tracking assembly mounted on the distal end of the tubular housing for maintaining a constant radial distance between the mirror of the beam deflection mechanism and the inner wall of the sleeve despite any irregularities which may be present in the roundness of the sleeve.

Abstract: System for inspecting the interior of tube plugs, particularly tube plugs of the type having expander elements disposed therein. The system includes a probe assembly connectable to the tube plug, the probe assembly having a rotatable and translatable probe carrier housing for housing a sensor probe capable of inspecting the tube plug. The probe assembly also includes a leaf spring extending through the probe carrier housing and attached to the sensor probe for radially outwardly biasing the sensor probe into sensing contact with the interior of the tube plug, particularly the interior of the tube plug located between the top of the tube plug and the expander element. A tangle-free flexible hose is connected at one end thereof to the probe carrier housing for transversely rotating and longitudinally translating the probe carrier housing. The flexible hose is also connected at the other end thereof to a probe driver assembly that rotates the flexible hose which in turn rotates the probe carrier housing.

Abstract: Process and apparatus are disclosed for removing and replacing the hold down beams of fluid circulating jet pumps mounted in a nuclear reactor. The disclosed process and apparatus are operable from a position such as the refueling bridge remote from the reactor and while the refueling cavity surrounding the reactor is flooded with moderator fluid.

Abstract: Process and apparatus are disclosed for removing and replacing the hold down beams of fluid circulating jet pumps mounted in a nuclear reactor. The disclosed process and apparatus are operable from a position such as the refueling bridge remote from the reactor and while the refueling cavity surrounding the reactor is flooded with moderator fluid.

Abstract: An apparatus and a method for remotely inspecting the interior walls of a cavity having a circular cross section that varies in diameter, such as the interior of a hollow tube plug. The apparatus has an eddy current probe head having a distal and proximal end, wherein the distal end engages the cavity walls, an elongated support assembly connected to the proximal end of the probe that is insertable within the cavity, a radial extender mechanism for radially extending and withdrawing the distal end of the probe with respect to the longitudinal axis of the support assembly, and a probe driving and delivery system for inserting the support assembly into the cavity and helically moving the probe head to inspect the cavity walls for discontinuities.

Abstract: An improved system for repairing and reconstituting a fuel rod assembly in the spent fuel pool of a nuclear power plant is disclosed herein. The improved system includes a height-adjustable elevator and carriage assembly for lifting and inverting a pair a fuel assemblies with their bottom ends adjacent one another, a length-adjustable rod handling tool having a gripper for gripping, lifting, lowering and ungripping a fuel rod, and a dual-axis tool positioner mountable over the bottom ends of the inverted, adjacent fuel assemblies. The tool positioner includes a funnel-shaped tool guide that is movable over the bottom ends of the fuel assemblies for receiving and positioning the gripper of the rod handling tool. The improved system may be adjusted for use in spent fuel pools of substantially different dimensions and water levels without the need for additional parts, and may be operated by only two technicians.

Abstract: A system for remotely repairing nuclear fuel rod assemblies is disclosed herein. Generally, the system comprises a rod handler for gripping, lifting, lowering and ungripping a selected fuel rod, a work station for securing the nuclear fuel rod assembly to be repaired into a desired location, and a positioner device for laterally positioning the rod handler over a selected rod in the fuel assembly secured within the work station. The rod handler includes a contractable collet for gripping and ungripping a desired fuel rod, and a rod sensor concentrically disposed within the collet for sensing when a rod is in a grippable position. The positioner includes a movable carriage which is slidably mounted onto a frame assembly by means of a pair of rail and bearing mechanisms. The system also includes a microcomputer for controlling the manner in which the positioner positions the rod handler, as well as gripping, lifting, lowering and ungripping motions of the handler itself.

Abstract: An improved apparatus and process for rotopeening metallic conduits of limited accessibility, such as the peripherally located heat exchange tubes around the tubesheet of a nuclear steam generator, is disclosed herein. The bowl-like inner wall which lies directly adjacent to such peripherally-located tubes renders it difficult to insert a rotopeening spindle into the open ends of these tubes in order to work-harden these tubes in the tubesheet region. Generally, the apparatus of the invention comprises at least one flexible rotopeening spindle, an advancing mechanism for remotely and incrementally advancing the flexible spindle through an open end of a selected peripheral tube, and a frame for supporting both the flexible spindle and the advancing mechanism. The length of the advancing mechanism is substantially shorter than the length of the flexible spindle so that the spindle and the advancing mechanism may be easily placed into a peening position with respect to the most remotely located tubes.

Abstract: A system constructed of three tools for manipulating fuel rods with a nuclear fuel assembly is disclosed. The individual tools are adapted for displacing fuel rods upwardly and downwardly along their longitudinal axes and for rotating same 360.degree. without having to remove the fuel rods from their location within a nuclear fuel assembly. The individual tools are operative on-site from a remote location while the nuclear fuel assembly is maintained underwater in a spent fuel pool. By manipulating the fuel rods, those areas previously hidden from visual inspection such as within grids may be inspected for defects and the like.