Abstract: The multiple fuel rod gripper comprises a plurality of split tube collets arranged to be inserted into corresponding tapered holes in a locking plate. When the gripper has been positioned to have a plurality of fuel rods disposed in the holes of locking plate, an actuating mechanism causes the collets to be inserted into the tapered holes thereby causing the fuel rods to be inserted in the collets. The taper of the holes forces the collets into locking engagement with the fuel rods so that the fuel rods may be extracted from the fuel assembly.

Abstract: A fine-motion control rod drive for a nuclear reactor, which can be disassembled in sections. The drive includes a spindle defining a sealing surface to prevent spillage after the drive motor is removed. A spline connection with a sliding key arrangement permits the shaft of the drive motor to be separated from the spindle during disassembly. The drive motor is effective for uncoupling the control rod drive piston from the control rod prior to disassembly.

Abstract: A latching device for use in nuclear reactors. The device is used to latch outer housing assemblies to the reactor core. The device contains a shear pin which does not break under normal loading imposed by movement of absorber rod assemblies, but which shears when it is desired to remove the housing from the core.

Abstract: The present invention relates to a device for handling a load, particularly an immersed load, by means of a shaft having a polygonal cross-section.The shaft, which can move along its axis, is maintained by a bearing connected to rotation means, so that a rotation of the bearing about the axis of the shaft leads to an identical rotation of the latter. The supply fluid for the bearing can be that in which the load to be manipulated is immersed.Application to the control and inspection of fuel rods.

Abstract: A lifting device for lifting and transporting nuclear fuel elements. This device comprises a mast-like support on the lower end of which automatically operated and locked gripping pawls are provided. The support has a considerable height and may be referred to as lifting mast. The gripping pawls and their operating mechanism are referred to as gripping-head. The gripping-head and the lifting mast are telescopically movable relative to each other. To this end guide rods and compression springs are interposed between the lower end of the lifting mast and the gripping-head. The gripping-head comprises two concentric annular members which are relatively movable or rotatable about their common geometrical axis. One of the annular members supports the gripping pawls pivotable in radial vertical planes. The gripping pawls are T-shaped. One of their transverse ends is adapted to engage the fuel rods, and the other of their transverse ends is adapted to engage curved grooves in the other annular member.

Abstract: Apparatus for loading and unloading fuel assemblies, for fast neutron nuclear reactors, and in particular for groups of fast neutron nuclear reactors cooled by liquid sodium located on one and the same site. The apparatus is removable as a unit and comprises a lock chamber (25) in the form of a removable and transportable vessel. The vessel (25) contains a pivoting ramp (35) allowing transfer of assemblies between the primary ramp (28) and the secondary ramp (29) of the nuclear reactor. Apertures (26) and (27) corresponding to the ramps (28) and (29) respectively are provided in the wall of the vessel (25) and connecting and isolating apparatuses (30) and (31) allow the lock chamber to be placed in communication with the ramps of the reactor, or conversely to be separated from the reactor and isolated.

Abstract: This system incorporates a uniquely coded longitudinally extending absolute distance standard or code chart. The code chart includes bars and segments of different light reflectivity characteristics which uniquely define every different distance increment along the chart. Preferably the chart is binary coded. A transducer optically detects the code at each different distance measurement increment and converts the code into electrical signals. The electrical signals operatively control a manipulator device which moves along a movement track parallel to the stationarily positioned chart. The transducer includes means for detecting the code at or near the center of each distance measurement increment, rather than at the edges of the distance measurement increments where the code on the chart undergoes transitions. A sample bar extending along the chart defines the distance measurement increments and the points at which the code at or near the center of the distance measurement increments is to be sampled.

Abstract: A nuclear reactor containing assemblies having two caps and a framework inside which fuel rods are disposed vertically is reloaded by first inverting the assembly to be removed into a vertical position permitting the then lower cap to be demounted. The spent fuel rods are then identified and removed in sets and deposited in a suitable storage area, and replacement rods are placed in sets in the framework of the fuel assembly. Finally, the lower cap is replaced and the assembly is conveyed into the reactor vessel at its new location.

Abstract: A grapple for handling nuclear reactor components in a medium such as liquid sodium which, upon proper seating and alignment of the grapple with the component as sensed by a mechanical logic integral to the grapple, automatically seizes the component. The mechanical logic system also precludes seizure in the absence of proper seating and alignment.

Abstract: A typical embodiment of the invention provides a nuclear fuel assembly lock structure for control rod guide tubes. Illustratively, a sleeve telescopes over an end portion of a control rod guide tube which bears against an internal shoulder of the tube. The upper end of the sleeve protudes beyond the control rod guide tube spider and is locked in place by means of a resilient cellular lattice or lock that is seated in a mating groove in the outer surface of the sleeve. A special tool is provided for disengaging the entire lock structure, washer, spider, spring and grill from the end of the fuel assembly in order to enable these components to be removed in an assembled state and subsequently replaced on the fuel assembly after inspection and repair.

Abstract: A reusable thermally actuated linkage arrangement includes a first link member having a longitudinal bore therein adapted to receive at least a portion of a second link member therein, the first and second members being sized to effect an interference fit preventing relative movement therebetween at a temperature below a predetermined temperature. The link members have different coefficients of thermal expansion so that when the linkage is selectively heated to a temperature above the predetermined temperature, relative longitudinal and/or rotational movement between the first and second link members is enabled. Two embodiments of a thermally activated linkage are disclosed which find particular application as actuators for a grapple head positioning arm in a nuclear reactor fuel handling mechanism to facilitate back-up safety retraction of the grapple head independently from the primary fuel handling mechanism drive system.

Abstract: Apparatus for charging a nuclear reactor disposed at the bottom of a pool. The reactor is constituted by a plurality of tiers of combustible assemblies having different stages of enrichment, each assembly having combustible rods and an auxiliary cluster associated with the particular tier of the assembly. The apparatus comprises a rolling bridge supported for movement in a plane above the pool, and carrying a turnable platform which supports a plurality of vertical telescopic manipulation arms arranged in angular spaced relation thereon. Each arm carries a respective grappling unit for respectively engaging a complete combustible assembly or at least one type of auxiliary cluster. The auxiliary clusters may include control clusters, sealing clusters and poison consumable clusters.