Abstract: Methods and assemblies for cleaning a control rod guide tube in a nuclear reactor are described. An assembly, in accordance with one embodiment, includes a support housing and a flush tube. The support housing includes a bore extending between its first and second ends. The flush tube also includes a bore extending between its first and second ends. The flush tube extends through the support housing bore and is movably coupled to the support housing adjacent the first end of the support housing. The second end of the flush tube extends from the support housing and includes a flush nozzle which is movable between a first, or latched, position and a second, or open, position.

Abstract: A restraint assembly which is a bolted lattice structure for preventing the in-core guide tubes from experiencing excessive flow induced vibrations is described. In one embodiment, the restraint assembly includes upper and lower restraint brackets secured to an in-core housing and in-core guide tube assembly. The restraint brackets are located approximately equal distance from the end supports of the in-core guide tube and in-core housing assembly. The upper restraint bracket is welded between sections of the in-core guide tube, and the lower restraint bracket is welded between the in-core guide tube and the in-core housing. Each bracket includes four flanges, and each flange has tapped, or threaded, openings therein. Each bracket also includes cylindrical sections extending from the flanges, and in one embodiment, the cylindrical sections have inner and outer diameters which match the inner and outer diameters of the in-core housing and the in-core guide tube.

Abstract: A fuel bundle assembly for a boiling water nuclear reactor includes an open ended tubular channel subdivided into four quadrants by at least two interior partitions, each quadrant having a sub-fuel bundle assembly having a plurality of fuel rods extending between upper and lower tie plates. An inter-bundle support plate receives a lower end of the channel and has four flow openings at an upper end thereof, such that the lower tie plate of each sub-fuel bundle supported in a respective one of the openings in the support plate. In one embodiment, the sub-fuel bundles within a channel are separated by a cruciform shaped coolant passage. In a second embodiment, the cruciform coolant passage is omitted to thus provide a homogeneous sub-fuel bundle configuration.

Abstract: A device for easily installing and removing strain gauge instrumentation and associated wiring on the inside of in-core monitor housings. A vibration sensor is attached to an inside diameter of a cylindrical housing. A signal cable is coupled to the vibration sensor and extends into an exterior of the reactor pressure vessel. A protective assembly minimizes the damage inflicted on the signal cables during handling. The signal cables are helically wound in an annular space between a pair of concentric thin-walled tubes and then passed through cable penetration bores formed in the body of a flange insert. The flange insert supports the concentric tube assembly and is sandwiched between the housing flange and the in-core monitor instrument flange of a conventional in-core monitor assembly.

Abstract: One aspect of the present invention comprises an apparatus for storing an end effector nestably adjacent a pipe to which it is attached and for moving the end effector into a working position laterally-displaced from said pipe is disclosed. Such apparatus desirably is part of the robotic welding apparatus wherein the end effector is a welding head. This apparatus comprises a pair of pipe segments in rotating end-abuttable relationship, each segment bearing a ring gear about its circumference; a pair of helical lotus petals having an in inner surface which conforms to the outer surface of the pipe segment to which each lotus petal is hingedly attached at its distal end, each lotus petal being attached hingedly at their respective distal ends to a lotus petal hinge attachment stage; drive means drivably connected to each of said ring gears for separately driving each pipe segment; and an end effector carried by said lotus petal hinge attachment stage.

Abstract: A stopper apparatus for use in blocking the unvalved nozzle of a cooling fluid filled nuclear reactor pressure vessel includes a plug, typically in the shape of a frusto-conical member having inflatable gaskets for sealing against a seat of generally unknown surface characteristics and means for positioning and urging the plug into position to seal the nozzle. The plug is typically positioned by suspension cables whereby the apparatus can be temporarily inserted and removed from the pressure vessel. The urging means is generally a two-way hydraulically driven jack controlled by remotely-actuated hydarulic lines. The apparatus is a tool which permits temporary sealing of a submerged outlet in a reactor vessel to permit maintenance on a fluid recirculation loop.

Abstract: A microprocessor controls pressure transducer testing, calibration, and adjustment. A transducer or unit under test (UUT) receives a fluid pressure signal from a test line, and outputs a corresponding electrical signal. A test pressure is output from a fluid pressure module which is connected to the UUT. A human operator is interrogated by the microprocessor based control unit as to (1) identifying details about the desired pressure UUT to be tested, and (2) the anticipated electrical range to be encountered in reply to an applied test pressure. The microprocessor then sequentially generates electrical output signals which are sent to the test lines to generate the test pressure pulses from a fluid pressure supply. The pressure test pulses are delivered to the UUT. As the UUT receives the sequence of pressure test pulses, the microprocessor records the output electrical signals generated by the UUT, and compares them to an internal reference pressure transducer output.