Patent Number: 043303684
Section: description

Turning now to the drawings, wherein like components are designated by like reference numerals throughout the various figures, attention is specifically directed to FIG. 1 which illustrates in part a liquid metal fast breeder reactor 10. This reactor is shown including a horizontally extending deck 12 directly above a vertically depending reactor vessel 14. The reactor includes a number of internal components, that is, components located within vessel 14. These components include a reactor core 16, an upper internal structure or instrument tree 18 which is located directly over the core in its normal operating position, a hoist arrangement 20 (extending inside and outside the vessel) and a fuel assembly track arrangement 22 for transporting fuel assemblies (not shown) into and out of the reactor core and vessel. These internal components as well as others not recited or shown are conventional and hence will not be described except as they affect the present invention. As discussed previously, it is periodically necessary to move hoist 20 to various points within vessel 14 for performing certain functions including transferring fuel assemblies between core 16 and track arrangement 22. This is accomplished by means of a conventional plug assembly 24 located at the top of the vessel in deck 12 and shown exaggerated in size relative to many other components of the reactor. This assembly includes three horizontally extending, circular plugs, an outermost plug 26 which is the largest of the three, an intermediate plug 28 which is eccentrically located entirely within plug 26 and an innermost plug 30 which is eccentrically located entirely within plug 28. All three plugs are conventionally mounted for rotation about their respective axes (indicated by center-lines 1, 2 and 3) and the overall assembly includes conventional means (not shown) for rotating these plugs, either individually or in specific combinations for appropriately locating hoist 20. Reactor 10 thus far described is conventional and includes other conventional components within vessel 14, as stated previously, and it also includes conventional components outside the vessel. In addition, the overall operation of reactor 10 requires power, instrumentation and service connections (both electrical and fluid carrying connections) between an internal location within the vessel and an external location to interconnect many of these internal components with many of the external components. This is best illustrated in FIG. 1 by the power, instrumentation and service cables which are generally indicated at 32 and which are to be operatively connected between instrument tree 28 (and other internal equipment) and an external location. As seen in FIG. 1, these cables pass out of vessel 14 through an eccentrically located opening 33 in intermediate plug 28. As will be seen hereinafter, reactor 10 includes a cable handling system 34 which is designed in accordance with the present invention and which is provided for connecting these latter cables to a predetermined external location through a series of cable sections, each of which may be made up of a group of different individual cable segments but which is continuous in length in a preferred embodiment. As seen best in FIG. 1, system 34 includes a vertically extending, tower 35 fixedly mounted to and extending out from the topside of plug 28, along the centerline of the latter. In an actual embodiment the tower includes a terminal box (not shown) at the base and a large cylindrical drum 36 at the top. As also seen in this figure, the overall length of power, instrumentation and service cables 32 between the internal components of the reactor and its external components includes a first section 32a extending through eccentric passageway 33 and through the previously recited terminal box at the base of tower 35 to a fixed terminal point 38 on the circumference of drum 36. Terminal point 38 is actually at the fixed end of a cable mechanism 72 which is partially wrapped around drum 36 and which will be described hereinafter. In this way, no matter how the three plugs 26, 28 and 30 rotate, terminal point 38 will be fixed relative to passageway 33 and, hence, cable section 32a will be fixed relative to the terminal point and plug 28. In this way, it is relatively simple to handle this cable section between passageway 33 on plug 28 and terminal point 38 by either passing the cable section through the passageway as shown or by providing a separate cable subsection on the topside of the plug and a separate cable subsection on the bottomside with appropriate terminal connections therebetween. On the other hand, the way in which the remaining sections making up cables 32 are handled is slightly more complicated but made as simple as possible and also reliable by handling system 34, as will be seen below. Turning specifically to FIG. 2 in conjunction with FIG. 1, attention is now directed to the remaining components making up the overall cable handling system. As seen in FIG. 2, this system also includes a horizontally extending, elongated rigid rail 40 defining an inner, channel 42 which extends along its underside and which opens downwardly. One end of this rail is connected to the top end of drum 36 by a pivot pin 44 or other such means which allows the drum to rotate freely about its own axis relative to the rail, as indicated by the arrow 46. The other end of rail 40 is free but includes an end section 48 which is supported in a particular way to be described below by a rail support arrangement 50. Rail support arrangement 50 includes a slide support 52 having a through-hole 54 for slidably receiving end section 48 of rail 40. Slide support 52 is pivotally mounted to the top end of a vertically extending chain guide 56 which includes a vertically extending through-hole or opening 58 and which is provided for reasons to be described hereinafter. The chain guide is in turn fixedly monted to the topside of a carriage 60 which as will be seen hereinafter comprises part of an overall traversing mechanism 62. As will also be seen, this latter mechanism serves to move the rail support arrangement 50 between two extreme positions and an intermediate (resting) position for pivoting rail 40 between two extreme positions and an intermediate rest position. However, assuming for the moment that carriage 60 remains fixed in one of the extreme positions as shown in FIG. 2, it can be seen that arrangement 50 supports rail 40 for rectilinear movement back and forth in the directions of two way arrow 64 and for rotational movement about the axis of chain guide 56, as indicated by two-way arrow 66. As stated above, traversing mechanism 62 includes carriage 60. This carriage is mounted on or within a suitable track 68 for movement between the extreme position shown in FIG. 2 and two positions one of which is the second extreme position shown in FIG. 4. The third position for the carriage is the resting position. The configuration of track 68 and the extreme positions for carriage 60 as shown in FIGS. 2 and 4 are selected to cause rail 40 to pivot about the axis of drum 36 between two predetermined, extreme positions, and the normal resting position for reasons to be discussed hereinafter. The carriage 60 may merely sit within a U-shaped track configuration as shown and move on appropriately provided wheels or other configurations may be provided such as longitudinally extending guide rails for the carriage to slide on. In any event, suitable means such as a carriage drive including wheels or a piston and cylinder arrangement shown generally at 70 may be provided for moving carriage 60 between its extreme positions. In addition to the foregoing, overall system 34 includes an elongated chain mechanism 72 which may be identical to the Powertrak or Aero-trak mechanism recited previously for containing a second section 32b comprising part of overall cables 32 described previously. This latter cable section and one end of mechanism 72 are fixedly connected to and partially wrapped around drum 36 at point 38 and the cable section 32b is operatively connected with or a continuation of previously recited cable section 32a. When sections 32a and 32b are distinct sections, suitable interconnecting means would be provided. These latter means include conventional electrical terminals in the case of electrical cables and valves in the case of hollow tube cables. The otherwise free end of chain mechanism 72 and the otherwise free end of cable section 32b are located at what may be referred to as an external, remote terminal 74 located on the far side of carriage 60. As seen in FIG. 2, chain mechanism 72 may be separated into two sections, a section 72a and a section 72b. Section 72a which is elongated cross-wise in the vertical direction passes through opening 58 in chain guide 56. Section 72b which is interconnected with section 72a by a suitable interconnecting member 72c is elongated cross-wise in the horizontal direction and is located on the backside of chain guide 56. For reasons to be discussed hereinafter, section 72a and its contained portion of cable section 32b is movable back and forth in a direction parallel with rail 40 and relative to the rail, as indicated by two-way arrow 76. This is accomplished by interconnecting section 72a to the rail by a number of spaced T-bars 78. As seen in FIG. 2, these T-bars extend up from and are fixed to chain section 72a by means of their stems and their cross-bars are slidably mounted within the previously described channel 42. Chain section 72b and its contained portion of cable section 32b bend around along the backside of guide 56 and carriage 60 and is free to flex back and forth with the rectilinear movement of chain section 72a. Overall system 34 includes a second chain mechanism 80 which may be identical to either the chain section 72a or 72b. However, chain mechanism 80 serves to contain a third cable section 32c and has one end fixedly connected to the back of carriage 60. In this regard, suitable means are provided on the carriage for operatively connecting cable section 32c with cable section 32b when the two are distinct sections or more likely section 32c may be a continuation of section 32b. The other ends of cable mechanism 80 and cable section 32c extend to a second external, remote terminal point on the underside of tracks 68, as seen in FIG. 2. The various cables may take off from this latter point in the same direction as indicated by a fourth section 32d, as shown, or they may take off in different directions depending upon the locations of the external reactor components to which they ultimately connect with. Having described cable handling assembly 34 from a structural standpoint, attention is now directed to the way in which it functions to contain cable section 32b and 32c regardless of the position of drum 36 and terminal point 38 on the drum, of course within a limited pattern of movement. In this regard, attention is directed to FIGS. 5a-d in conjunction with FIGS. 2-4. As seen first in FIG. 5a, the three plugs 26, 28 and 30 are positioned as shown in FIGS. 1 and 2, that is, with terminal point 38 somewhat rotated from side support 52 and chain guide 56 and with passageway 33 in line between the chain guide and drum 36. In these positions, it should be apparent that most of section 72a of chain mechanism 72 lies on the drum side of chain guide 56 and that only a portion of this chain section is wrapped around the drum. In this regard, it is desirable to maintain a sufficient portion of the chain section wrapped around the drum in this operational position so that the wrap is in one direction regardless of the operation of the overall system, that is whether or not the drum rotates clockwise or counter-clockwise. For example, in the embodiment shown, if the drum rotates clockwise (FIG. 2) the initial wrap will unwrap to some degree while counter-clockwise rotation of the drum increases the wrap around the latter. It should also be apparent that most of the rail 40 lies on the drum side of slide support 52. Also, the carriage 60 is in the position shown in FIG. 2. With this positional relationship as a starting point, the operation of system 34 will be described below. Assume now that intermediate plug 28 rotates in the direction of arrow 82 as in FIG. 5b but that plug 26 remains stationary. In this case, rail 40 will remain stationary but drum 36 will rotate counter-clockwise causing an additional segment 72a' of chain section 72a to wrap around the drum in the manner shown in FIG. 3, along with a corresponding segment of the cable section 32b. This will cause the rest of section 72a and 72b and the rest of cable section 32b to move towards the drum along the underside of rail 40 as supported by T-bars 78. The excess motion is compensated by a reduction in the 72b trailing loop. As an alternative, assume now that intermediate plug 28 remains stationary and that plug 26 rotates in the direction of arrow 84 as shown in FIG. 5c. In this case, it should be apparent that the entire drum 36 actually moves closer to the rail support assembly 50 and at a different angle therewith. To compensate for this change, slide support 52 pivots at rail 40 and the latter slides further into the slide support, as seen in FIG. 5c. At the same time, it should also be apparent that terminal point 38 on drum 36 actually rotates around the axis or centerline of the larger plug 26 even though plug 28 remains stationary. As a result, a segment 72a' of chain mechanism 72 and its associated cable section segment will wrap around the drum, again in the counter-clockwise direction, as described previously. Obviously, the actual amount of cable which is wrapped around the drum may be different than the amount previously described. This motion is again compensated by the trailing loop 72b moving in or out. Rotation of the drum in the clockwise direction will of course cause some of the wrap 72a' to unwrap. It should be obvious that the rotational situations just described could be provided simultaneously, that is, outermost plug 26 and intermediate plug 28 can rotate simultaneously in the same or opposite directions. In this case, the chain mechanism may or may not wrap around the drum 36 (over and above its original wrap) since it is possible that the rotation of plug 28 could be such as to cancel out the rotation of plug 26 from this standpoint. However, even under these circumstances, drum 36 would either move closer to or further from the rail support assembly and hence rail 40 and the chain mechanism 72 would move in the directions of arrows 64 and 76 (FIG. 2) either towards or away from the cable support assembly, depending upon the particular way in which the two plugs rotate. As seen in FIG. 5d, there are situations where it is necessary to move previously described hoist 20 and hence inner plug 30 to a point where rail 40 and chain mechanism 72 have been located (FIGS. 5a-c). This is accomplished by rotating plug 28 about 180.degree.counter-clockwise from its FIG. 5a position as indicated again by arrow 82, while maintaining the other two plugs stationary. In this case, it is necessary to move the rail and chain mechanism to a different location, specifically from the dotted line locations of FIG. 5d to the solid line locations shown therein. This is accomplished utilizing previously described traversing mechanism 62. More specifically, by moving carriage 60 from the position shown in FIG. 2 to the position shown in FIG. 4, the entire rail support assembly moves with it causing the rail and chain mechanism 72 to pivot about the axis of drum 36 from its dotted line position to its solid line position in FIG. 5d. In doing so, it should be apparent from FIGS. 2 and 4 that the chain mechanism 80 and cable section 32 c move with the carriage. In this regard, it should be obvious that both this latter chain mechanism and cable section must be at least as long as the distance between the two extreme positions of the carriage. For fuel hoist operation in the clockwise direction, motion is reversed and the cable mechanism 72a tends to unwind from drum 36a and the carriage 60 moves in the opposite direction. Cable motion is still handled in the same way except that the trailing loop 72b tends to elongate to take up the now excess section 72a being unwrapped from drum 36. From the foregoing, is should be apparent that system 34 is not limited to the exact reactor described, that is, LMFBR, but could be used to handle cables in the manner described where necessary but in different installations and environments. Moreover, the chain mechanism themselves are not limited to the particular ones recited so long as they function in the manner described, that is, to contain the cable sections and move and wrap to compensate for movement of drum 36.