Patent Number: 042882923
Section: description

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1 there is shown a nuclear reactor including a reactor vessel 10 sealingly affixed to a vessel head 12. The vessel is supported within a stationary enclosure, such as a concrete support 11. A nuclear core 14 comprised of a plurality of vertically oriented fuel assemblies is positioned within the vessel so that a coolant fluid, such as liquid sodium or gaseous helium, can be circulated through the core 14. The fluid enters the vessel 10 through a plurality of inlet nozzles 18, flows upwardly through the core, absorbing heat energy, and is discharged through outlet nozzles 20 to heat transfer and other apparatus, typically for the ultimate purpose of electrical power generation. The vessel head 12 includes a stationary outer ring 22, a large rotating plug 24, an intermediate rotating plug 26, and a small rotating plug 28. The stationary outer ring is concentrically arranged about the large plug 24, while the intermediate 26 and small 28 plugs are arranged off-center. For refueling or maintenance, the plugs are rotated in a preselected sequence which positions an in-vessel transfer mechanism 30 directly above each core assembly location. The transfer mechanism 30 is typically positioned upon the small rotating plug 28 during refueling periods, and is subsequently removed from the vessel head area until the next refueling or maintenance outage. During reactor power generation, and also during refueling, hundreds of electrical and other connections must be maintained between equipment external to the vessel 10, and within the vessel and stop the rotating plugs. The connections are made through a plurality of conduits such as cables 32 which transfer power, fluids, and electrical signals for reactor control and instrumentation. Typical of the services supplied merely through the transfer machine are those for heaters, motor drives, jacks and blowers, limit switch connectors, compressed gases, thermocouples and ground wires. Hydraulic services can also be supplied. In accordance with this invention the cables or hoses are supported within vertically oriented compartments 34, shown best in FIG. 2. It is to be understood that the following description of invention embodiments as applied to a nuclear reactor is merely exemplary, and that the invention can advantageously be used in many other applications involving limited reciprocating rotary or rectilinear motion among members. The figure shows one structural arrangement for the compartments 34, which includes a plurality of upper vertical plates or surfaces 36 and a plurality of second lower vertical surfaces 38. Substantially all of the surfaces 36, 38 include a laterally extending restraint 40, which can together form an integral upper plate 42 or lower plate 43, extending along the width of the plurality of surfaces 36, 38. The affixed set of lower surfaces 38 are affixed to one of the relatively movable members, such as the intermediate rotating plug 26, and the upper set of surfaces is affixed to the other member, such as the small rotating plug 28. Both the upper and lower surfaces are also provided with means for affixing the surfaces to their respective supporting members, such as welds 48 or bolts 50 or other fastening devices. The vertical surfaces 36, 38 need not be directly affixed to the relatively movable members, but can be affixed to extension components such as the riser plate 51. As the elevation of the relatively movable members such as the intermediate 26 and small 28 rotating plugs is typically fixed, each set of vertical surfaces is affixed to the respective member so as to laterally align the surfaces 36, 38. The surfaces are also affixed to the members with a preselected gap or space 52 between the laterally aligned surfaces. The gap 52 allows free relative motion, the upper surfaces 36 not contacting the lower surfaces 38. The vertical surfaces 36, 38 can have various shapes, dependent on the type of motion of the two members. As shown in FIG. 3, where rotary motion is required, the surfaces are arcuate or circular, although they are preferably rectangular for relative rectilinear motion. The surfaces 36, 38 can be comprised of any structurally sound material, although they are preferably metallic and capable of providing electrical signal separation between laterally adjacent compartments 34. The cables 32 are positioned between two consecutive aligned upper 36 and lower 38 surfaces, between their respective restraints 40, so that each cable forms a singular generally rotated-U-shaped or C-shaped loop 56 in a substantially vertical plane. A plurality of cables 32 can be positioned between one aligned pair of surfaces 36, 38. The cables are then positioned adjacent one another such that the loop 56 of one cable (56a) is contained within the horizontal area enclosed by the loop (56b) of its adjacent outermost cable. This necessarily requires that the bend radius 58a be smaller than the bend radius 58b. The term "radius" is here used to define the substantially circular shape each loop will take, although the loop will not be perfectly arcuate. The number of cables between any two sets of consecutive vertical surfaces is therefore determined by the minimum allowable cable bend radius and the height of the surfaces, 36, 38 between respective restraints 40. Although cables 32 of varying size and shape can be utilized, in the preferred nuclear reactor arrangement all of the cables are of circular cross section, with a substantially common outside diameter of 1 in..+-.1/8 in. The height of the gap 52 is preferably smaller than the cable diameter to alleviate any possible binding upon motion. Also, the lateral spacing between consecutive parallel vertical surfaces 36, 38 is less than two cable diameters to alleviate crossing of cables upon rotation or translation. A spacing providing approximately 11/2 times the cable diameter between consecutive surfaces is preferred. The cables 32 can extend from one movable member to the other, or terminate in quick-disconnect electrical or fluid apparatus 63 such as that shown in FIG. 6. Portions of the cables, such as their end portions, are, however, substantially fixed or stationary relative to the respective movable members. These portions of the cables can also be held in place by means such as clips 64 shown in FIG. 3. The required length of the cables will, of course, be determined in accordance with the amount of rotary or rectilinear travel and the size of the relatively movable members. The upper surfaces 36 are also provided with a plurality of flexible devices 65 for supporting the upper portion of each looped cable. One embodiment of a device 65 is shown in additional detail in FIG. 4, and includes a body or wire 66 affixed by a bearing 67 to vertical surface 36 and to the horizontal surface 40 by a bearing 73. The wire is shaped to have a generally vertical upper section 68 and a generally crimped or triangular lower segment 69 positioned 90.degree. from surface 36 by spring 71. The lower segment includes a portion spaced from vertical surface 36a a distance less than the diameter of the cables. The vertical section 68 is spaced from vertical surface 36a a distance greater than the cable diameter. A crimped rectangular segment 70 is positioned about the central portion of spring 71. Upon relative motion of the members in one direction, the loops of the cables contact the protruding triangular segment from below, rotate the segment laterally sliding and compressing spring 71, and pass above the segment, which rotates back to a position substantially perpendicular to surface 36, so as to then be supported atop the triangular segment. Upon relative motion in the opposite direction the loops cause the segment to rotate laterally and allow the cables to pass freely from the device 65. The device 65 can take many alternative configurations, including others which can be rotated, pushed aside or flexed by the passing cable loops to spring back into position to support the upper portion of the cables, or pushed aside as the cables return to the lower position. The operation of the connecting apparatus is simple, having a minimal number of moving components. In addition to the movable members, only the affixed vertical surfaces, the cables themselves, and the affected flexible devices 65 are in motion. Rectilinear movement is illustrated in FIGS. 5A, 5B, and 5C. These figures can also be viewed as illustrating relative rotary motion. The cables 32 and surfaces 36, 38 are initially positioned as shown in FIG. 5A. In this example, the upper surface 36 is fixed, while the surface 38 is moved from left to right, as shown by the arrow to, for example, the positions shown in FIGS. 5B and 5C. As shown, a portion of the cables is transferred from adjacent the lower surfaces 38 to adjacent the upper surfaces 36, as the loops 56 and cables slide. If the figures are viewed in reverse order, that is, from FIG. 5C toward FIG. 5A, it is seen that a portion of the cables shift from the upper surfaces to the lower surfaces. It is also seen that the cables will move into and out of the flexible devices 65 through the loops 56. Another embodiment is shown in FIG. 6, the operation of which is illustrated in FIGS. 7A, 7B, and 7C. Here the cables 32 terminate in the quick-disconnect boxes 63. A lower box is affixed to an extension of the intermediate rotating plug 26, and an upper box is affixed to the small rotating plug 28. A third box is affixed to the in-vessel transfer mechanism 30, shown being lowered into position atop the small rotating plug. The lower vertical surfaces 38 are affixed to the intermediate plug extension, and the upper surfaces 36 are affixed to the transfer mechanism. The second disconnect box is affixed to support 95, so that the support 95 and the box are supported by and slide across a plurality of rollers 96 affixed to the intermediate plug extension. As the small rotating plug 28 and in-vessel transfer mechanism 30 are rotated, the cables 32 will slide onto, and from, the rollers 96. This is illustrated in FIGS. 7A, 7B, and 7C, exemplifying the situation where the rollers 96 and the lower box 63 are maintained stationary. Upon rotation of the upper box 63 from left to right, the cables are shown to slide off of the rollers. In the opposite direction, the cables conversely will slide onto the rollers. Although this embodiment eliminates the flexible devices 65, it requires the additional roller components 96. Further, the amount of rotation is limited relative to that attainable with the flexible devices 65. Further, it can be seen that a portion 97 of the cables will freely bend, significantly contributing to wear. The cables must be much stiffer for this embodiment in order to operate satisfactorily. It will be apparent that many additional features can be incorporated in the connection apparatus, particularly for nuclear application. For example, a seal can be placed across the gap 52 of the outermost or innermost surfaces 36, 38 to insure that objects are not accidentally inserted through the gap. Also, for additional electrical separation or hazard protection, some compartments 34 can be left empty or filled with a suitable material. It will also be apparent that the connecting apparatus provides reliable operation and ease of maintenance or cable replacement. The cables can be replaced merely by disconnecting the extremities, removing the old cables from between surfaces 36, 38, and reinserting new cables in the looped configuration. Also, it will be noted that the described apparatus is particularly applicable where limited lateral space among components is available. Many additional modifications are possible in view of the above teachings. It therefore is to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.