Abstract: An emergency retraction means is provided for removing the extended manipulator arm of a nuclear reactor vessel inspection device from within a nozzle thereof or from a fully extended position should power for normal extension drive fail. A cable is looped about the interior of a carriage assembly which drivingly engages the remainder of the manipulator arm. The cable is fixedly clamped at one location within the carriage assembly and looped about a first idler pulley mounted in the manipulator arm and is guided therefrom by another idler to an accessible point where the end of the cable is formed into a ring. The ring is detachably secured thereat to the carriage assembly.When an emergency occurs, a hook is lowered to engage the ring and is then lifted to detach it from the carriage assembly and move it upwardly therefrom.

Abstract: An air pressurized coaxial cabling system is disclosed for carrying electrical cables and air simultaneously to and from underwater junction boxes and electrical elements employed in a nuclear reactor vessel inspection device. An electrical cable is routed to a sealed junction box which is also supplied from a source with pressurized air. The electrical cable and air exit the junction box coaxially and are routed therefrom to an underwater junction box wherein the pressurized air prevents water seepage and allows the use of ordinary electrical connectors and components.

Abstract: A remote access manipulator for performing operations on equipment located in areas where human access is limited. The manipulator comprises a slave carriage located in the equipment on which the operation is to be performed, such as a nuclear steam generator, for carrying tools and inspection devices for performing operations on the equipment together with a master carriage located in a scale model of the equipment and electrically connected to the slave carriage for controlling the movement of the slave carriage. The slave carriage comprises a five link mechanism with the links rotatably connected and is capable of advancing across a surface of the equipment to position the devices which it carries. The manipulator further comprises a slave manipulator arm used to move the slave carriage into and out of the equipment on which the operation is to be performed in conjunction with a master manipulator arm located in the scale model for controlling the movement of the slave manipulator arm.

Abstract: A control rod assembly for a nuclear reactor is disclosed having a remotely disengageable coupling between the control rod and the control rod drive shaft. The coupling is actuated by first lowering then raising the drive shaft. The described motion causes axial repositioning of a pin in a grooved rotatable cylinder, each being attached to different parts of the drive shaft which are axially movable relative to each other. In one embodiment, the relative axial motion of the parts of the drive shaft is used either to couple or to uncouple the connection by forcing resilient members attached to the drive shaft into or out of shouldered engagement, respectively, with an indentation formed in the control rod.

Abstract: A flow baffling arrangement for the core of a nuclear reactor. A plurality of core formers are aligned with the grids of the core fuel assemblies such that the high pressure drop areas in the core are at the same elevations as the high pressure drop areas about the core periphery. The arrangement minimizes core bypass flow, maintains cooling of the structure surrounding the core, and allows the utilization of alternative beneficial components such as neutron reflectors positioned near the core.

Abstract: A nuclear reactor including two rotatable plugs and a positive top core holddown structure. The top core holddown structure is divided into two parts: a small core cover, and a large core cover. The small core cover, and the upper internals associated therewith, are attached to the small rotating plug, and the large core cover, with its associated upper internals, is attached to the large rotating plug. By so splitting the core holddown structures, under-the-plug refueling is accomplished without the necessity of enlarging the reactor pressure vessel to provide a storage space for the core holddown structure during refueling. Additionally, the small and large rotating plugs, and their associated core covers, are arranged such that the separation of the two core covers to permit rotation is accomplished without the installation of complex lifting mechanisms.

Abstract: An internal tube cutter for cutting the inside of tubes of a nuclear steam generator comprises an extendable cutter capable of being disposed within a tube of a steam generator along with a flexible transverse positioning mechanism disposed on the cutter for positioning the cutter within the tube. The cutter is attached to a drive mechanism that is capable of rotating the cutter when the cutter is in an extended position to thereby cut the inside of the tube. The cutter and flexible transverse positioning mechanism are capable of being inserted into and traversing through tubes whose inside diameter is severely reduced due to denting while being capable of being extended and severing the tube at a section of the tube having a normal diameter.

Abstract: A swing check valve which includes a valve body having an inlet and outlet. A recess in the valve body designed to hold a seal ring and a check valve disc swingable between open and closed positions. The disc is supported by a high strength wire secured at one end in a support spacer pinned through bearing blocks fixed to the valve body and at its other end in a groove formed on the outer peripheral surface of the disc. The parts are designed and chosen such to provide a lightweight valve disc which is held open by minimum velocity of fluid flowing through the valve which thus reduces oscillations and accompanying wear of bearings supporting the valve operating parts.

Abstract: An arrangement for enclosing press apparatus, including a die set and a reciprocating punch block, within a hazardous environment. The die set and punch block are sealed within an enclosure room into which an elongated drive shaft, which connects the punch block and a drive unit, passes. The drive shaft is sealed at the point where it passes from inside to outside of the room, while allowing the shaft to reciprocatingly move. The arrangement provides access to the drive unit for maintenance, external to the hazardous environment and, in the event of a release of hydraulic fluid in an hydraulic drive, the fluid is maintained segregated from the hazardous environment and the material therein.

Abstract: A nuclear fuel assembly storage rack having a swivel base consisting of a plurality of plates with a hard ball centered and captured between the plates. The bottom base plate is fixed to the bottom of the storage rack and the top base plate has pins for locating the bottom nozzle of the fuel assembly. Since the top of the fuel assembly is clamped in the storage rack, the swivel base allows the fuel assembly to seek a position that minimizes torsional and bending stresses in the fuel assembly.

Abstract: An apparatus for efficiently and safely recombining hydrogen and oxygen gas to form water vapor, the apparatus being particularly adapted for use with a nuclear reactor system in which potentially dangerous hydrogen gas, evolved within the containment vessel during certain postulated accident conditions, can be eliminated. Further, this apparatus also aids in the removal of certain radioactive contaminents from the gases in a containment vessel.

Abstract: Apparatus for determining pellet length and end squareness which includes a base supporting a pair of linear variable differential transformers (LVDT) between which a pellet is placed for measuring end squareness. The LVDT's are perpendicularity detectors and each includes appropriate windings contained in a housing and an armature axially slidable therein. The armature is mounted on a shaft having extensions on opposite ends thereof. A swivel plate is attached to one end, while the other end is supported in a framework for the inspection apparatus, the arrangement being such that the housing containing the windings moves axially relative to the stationary armature. When a pellet is placed in position, each detector is advanced toward the pellet until its swivel plate contacts the pellet ends. If the pellet ends are not square, the swivel plates cock at an angle, thereby displacing the windings with respect to the armature.

Abstract: A method of welding tabs projecting outwardly from grip straps in a fuel assembly grid to a control rod guide thimble positioned in a cell in the grid including providing a weld guide having openings therein which receive dimples on the strap when the weld guide is placed in a cell adjacent to the cell containing the control rod guide thimble. THe weld guide includes an opening which falls into alignment with a tab so that when a welding gun electrode is placed through the opening and into contact with a tab, the other electrode is automatically centered on its tab thus permitting accurate spot welding of the parts. To make a second spot weld on the same tab but at a point outwardly from the first spot weld, a second weld guide having an opening therein displaced a greater distance from a reference point on the weld guide, is placed in the same cell and the welding process repeated.

Abstract: Apparatus for establishing a solid, very low permeable rock glass plug to seal access holes through rock to underground storage vaults. The apparatus is designed to supply a filler material having a constituency substantially matching that of the rock formation surrounding the access port to the vault, through a central feeder tube under pressure to the vault. Means are provided for heating the filler material and surrounding rock formation at the point where the filler material exits the feeder tube, to a temperature sufficient to melt both the rock formation and the filler material. The remaining portion of the feeder tube is cooled to preserve the surrounding rock formation spaced from the feeder orifice. The melt at the extremity of the feeder tube is forced through the orifice to a region below the tool by the force of the pressure feed. As the melt is forced below the tool, the tool is retracted until the access hole is completely sealed.

Abstract: A method of accurately verifying the pressure contained in a sealed pressurized fuel rod by utilizing a pressure balance measurement technique wherein an end of the fuel rod extends through and is sealed in a wall of a small chamber. The chamber is pressurized to the nominal (desired) fuel rod pressure and the fuel rod is then pierced to interconnect the chamber and fuel rod. The deviation of chamber pressure is noted. The final combined pressure of the fuel rod and drill chamber is substantially equal to the nominal rod pressure; departure of the combined pressure from nominal is in direct proportion to departure of rod pressure from nominal. The maximum error in computing the rod pressure from the deviation of the combined pressure from nominal is estimated at plus or minus 3.0 psig. for rod pressures within the specified production limits. If the rod pressure is corrected for rod void volume using a digital printer data record, the accuracy improves to about plus or minus 2.0 psig.

Abstract: A structural support system for the core of a nuclear reactor which achieves relatively restricted clearances at operating conditions and yet allows sufficient clearance between fuel assemblies at refueling temperatures. Axially displaced spacer pads having variable between pad spacing and a temperature compensated radial restraint system are utilized to maintain clearances between the fuel elements. The core support plates are constructed of metals specially chosen such that differential thermal expansion produces positive restraint at operating temperatures.

Abstract: Apparatus for sealing the annulus defined within a substantially cylindrical rotatable riser assembly and plug combination of a nuclear reactor closure head. The apparatus comprises an inflatable sealing mechanism disposed in one portion of the riser assembly near the annulus such that upon inflation the sealing mechanism is radially actuated against the other portion of the riser assembly thereby sealing the annulus. The apparatus further comprises a connecting mechanism which places one end of the sealing mechanism in fluid communication with the reactor cover gas so that overpressurization of the reactor cover gas will increase the radial actuation of the sealing mechanism thus enhancing sealing of the annulus.

Abstract: A punch press remotely disengageable from the punch drive mechanism, particularly useful where the press must operate in a hostile environment. The press includes a punch block, supporting one or more punches, which is laterally inserted into connection with the punch drive apparatus. A die set is provided for supporting one or more dies, and the die set is associated with the punch block such that the punch is guided into a preselected position relative to the die by the drive apparatus. A structural frame is provided for seating the die set, which can be laterally inserted and removed from the frame. Guide rails are also provided which can extend laterally from the frame and support the die set in a position removed from the normal operating position within the frame. The guide rails also support the die set in the operating position.

Abstract: A dynamoelectric machine having a quiet cooling system. The system comprises at least twenty-five short chord axially mounted radial blades disposed on a conical hub which is disposed on the rotor of the dynamoelectric machine. The arrangement and number of blades are such that the coolant flow is increased while the pure tone noises are reduced thus increasing cooling and reducing subjective annoyance. A conical shroud encloses the conical hub defining therebetween a conical annulus whose total annular cross-sectional area does not expand to the point where turbulence and flow separation would occur. A bell-mouthed protective grilled inlet is disposed on the conical shroud for conducting a coolant, under the action of the rotating blades, through the bell-mouthed inlet and into the conical annulus. The bell-mouthed inlet and conical annulus together providing a streamlined path for quietly diffusing the coolant into the proximity of surfaces susceptible to heating.

Abstract: A lateral restraint and control system for a nuclear reactor core adaptable to provide an inherent decrease of core reactivity in response to abnormally high reactor coolant fluid temperatures. An electromagnet is associated with structure for radially compressing the core during normal reactor conditions. A portion of the structures forming a magnetic circuit are composed of ferromagnetic material having a curie temperature corresponding to a selected coolant fluid temperature. Upon a selected signal, or inherently upon a preselected rise in coolant temperature, the magnetic force is decreased a given amount sufficient to relieve the compression force so as to allow core radial expansion. The expanded core configuration provides a decreased reactivity, tending to shut down the nuclear reaction.