Abstract: The safety device consists of doubling a first reel (4) equipped with an operating cable (11) from a carriage (24) for nuclear fuel elements is suspended, by a second reel (5) equipped with an emergency cable (12) connected with the carriage (24) and following the displacement of the carriage in a synchronous manner with the aid of a set of cog-wheels (6 and 7) joined respectively with the reels (4 and 5) by means of reducing gears (2 and 3) and connected with each other by a notched belt (8).To attenuate the impact in case of a rupture of the operating cable (11) and the loading of the emergency cable (12), the carriage (24) is equipped with an attenuating system (22) and an elastic connecting system (20).

Abstract: The specification discloses a device (32) for raising peripheral fuel rods of a fuel assembly for inspection under submerged conditions in a nuclear reactor facility. The device (32) includes a frame comprising top and bottom plates (36, 38) interconnected by rods (40) with an intermediate plate (52) supported therein for vertical movement responsive to a cylinder (60). A yoke (64) is mounted for horizontal movement on the intermediate plate (52) responsive to another cylinder (66) to engage a fuel rod so that it can then be lifted by the first cylinder (60). Proper alignment relative to the peripheral rods of the fuel assembly is accomplished by means of pins (50) which are received in indexing holes (80) of a support plate (68) for the fuel assembly.

Abstract: A fuel pin transfer tool has a latching device of the collet type attached to a first member movable vertically through a long work stroke enabling a fuel pin in an under water assembly to be engaged and withdrawn therefrom or placed therein and released. The latching device has a collet provided with a plurality of resilient fingers having cam portions normally spaced apart to receive the upper end of a fuel pin between them and a second member, movable vertically through a short stroke relative to the first member is provided with cam portions engageable with those of the fingers and is yieldably and resiliently held in a raised position in which its cam portions engage those of the fingers and force the fingers into their pin-gripping positions.

Abstract: Apparatus for transferring, not only the fuel assemblies, but other component assemblies including control-rod assemblies, thimble-plug assemblies, poison assemblies and the like during refueling of a nuclear reactor. The apparatus includes an outer mast for guiding and protecting the component assemblies which are transferred, an inner mast movable vertically within the guiding mast. The inner mast has grippers for engaging and lifting or lowering fuel assemblies. The outer mast has internal grooved rollers along its length. The inner mast is formed at oppositely facing channels held in a rigid assembly by plates to which the channels are secured. Opposite corners formed by the flanges and the webs of the channels penetrate into the grooves of the rollers and the inner mast is guided and held in position by the rollers. The apparatus also includes an elongated tube within the inner mast movable vertically relative to the inner mast.

Abstract: The invention provides an automatic channel box fitting position adjusting apparatus to facilitate positional adjustment of a channel box for fitting onto a nuclear fuel assembly. The apparatus comprises a position adjusting mechanism and a jig having a rod for controlling the position adjusting mechanism. The position adjusting mechanism includes guide rollers to guide the channel box to a correct fitting position. The guide rollers are tapered toward outer ends and are cantilevered at inner ends thereof.

Abstract: Fuel assemblies of a nuclear reactor are transferred during fueling or refueling or the like by a crane. The work-engaging fixture of the crane picks up an assembly, removes it from this slot, transfers it to the deposit site and deposits it in its slot at the deposit site. The control for the crane includes a strain gauge connected to the crane line which raises and lowers the load. The strain gauge senses the load on the crane. The signal from the strain gauge is compared with setpoints; a high-level setpoint, a low-level setpoint and a slack-line setpoint. If the strain gauge signal exceeds the high-level setpoint, the line drive is disabled. This event may occur during raising of a fuel assembly which encounters resistance. The high-level setpoint may be overridden under proper precautions. The line drive is also disabled if the strain gauge signal is less than the low-level setpoint.

Abstract: A fuel pin transfer tool has a tubular housing of sufficient length to enable it to be suspended in a body of water in which a fuel pin assembly is submerged with the upper end of the housing above the water and with the tool in vertical alignment with a selected fuel pin from which the lower end of the tool is closely spaced. The housing has a cylinder spaced from its ends in which there is a piston having a tubular piston rod extending slidably through both ends of the cylinder. An actuator, the control for which has first and second positions, is fixed on the upper end of the piston rod and has a member extending freely downwardly therethrough which on short downward travel, resulting when the control is in its second position, effects the pin-releasing position of a latching device secured to the lower end of the piston rod.

Abstract: In a nucler reactor containment structure, a fuel transfer arrangement including a bridge, trolley, and grapple, each of the latter having a position sensor mounted thereon, and control means for determining the position of bridge, trolley, and grapple in response to signals from said position sensors, whereby fuel assemblies may be transferred between locations in the containment structure.

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: The invention relates to an assembly for passage through a containment slab for transferring irradiated nuclear fuel, comprising a sleeve passing through the slab and fast therewith and a guide ramp passing through the sleeve and in which moves a handling pot carrying the fuel, wherein said assembly further comprises a device for evacuating the residual heat dissipated by the fuel, this device comprising a bundle of caloducts disposed parallel to the ramp over a length at least equal to that of the sleeve, and means for evacuating the flow of heat directed above the slab by the caloducts.

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 refueling machine for inserting and removing fuel assemblies from a nuclear reactor including a pair of concentrically disposed stationary masts mounted on a movable bridge which spans the containment walls of the reactor. The bridge supports a trolley movable transversely to bridge movement thus providing an arrangement wherein the masts can be precisely positioned over a fuel assembly in the reactor core. A hoist mounted on the outer of the masts supports a vertically movable inner mast of a size sufficient to enclose a fuel assembly. An actuator tube inside the inner mast moves gripper fingers on the bottom thereof into engagement with the top nozzle of a fuel assembly prior to lifting it upwardly out of the reactor core.

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.