Patent Number: 045253242
Section: description

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION Reference numeral 5 designates a longitudinally-extending storage building of a dry storage facility. The building 5 contains storage modules 7, 9, 11 and 13. Storage modules 7 and 9 are arranged on one longitudinal side of the building and storage modules 11 and 13 are on the other longitudinal side thereof. Storage module 13 is shown without any covering. Each of the storage modules is configured as a separate unit and has a square base area. The modules are arranged in the building 5 so that the diagonal plane defined by one pair of diagonally opposite vertical corners of each module extends in a direction parallel to the longitudinal walls 6 and 8 of the building 5. Supporting and guiding rails 15 and 17 are mounted in the building 5 and extend in a direction parallel to the longitudinal walls 6 and 8. A bridge crane 19 is mounted on the rails 15 and 17 so as to be movable therealong. The supporting rail 15 extends approximately over the diagonal planes of respective storage modules 7 and 9; whereas, rail 17 extends approximately over the diagonal planes of storage modules 11 and 13. The storage building 5 includes a base plate 21 made of concrete in which are formed four square openings 23 for receiving the storage modules 7, 9, 11 and 13, respectively. Each of the storage modules 7, 9, 11 and 13 is bounded by vertical concrete walls 24, 25, 26 and 27 with a concrete top covering 28. The supporting rails 15 and 17 upon which the bridge crane 19 runs are fixedly mounted above the storage modules 7, 9, 11 and 13. The bridge crane 19 is part of a transport vehicle 20 which includes a transport apparatus 29 movable in a direction transverse to the supporting rails 15 and 17 of bridge crane 19. The transport apparatus 29 includes a transport mast 31, a receiving apparatus 32 for receiving the storage containers 33 and a small vehicle 35. The receiving apparatus 32 is rotatably mounted on the mast and is provided with a pushing apparatus 37 which can move the storage containers 33 out of the receiving apparatus 32 in the direction of the longitudinal axis of the containers 33. The containers 33 are used to store irradiated nuclear reactor fuel rods and can be 4 to 5 meters in length and have a diameter of approximately 0.38 meters. A pass-through opening 41 is provided in the concrete wall 43 at the entrance of the storage building 5 through which the individual storage containers 33 can be brought into the storage building 5. The storage modules 7, 9, 11 and 13 are supplied with fresh cooling air via an air inlet conduit 45 of large cross section and branch conduits 47. The storage modules are fed by the branch conduits 47. The cooling air warms as it rises and is directed by exhaust conduit 48 to a main exhaust conduit 49. An exhaust conduit 48 is arranged atop each of the storage modules and extends over the triangular half section of each storage module facing away from the transport passageway 61. The other triangular half section of each module 7, 9, 11 and 13 is provided with a roof-like concrete covering 28 above which the transport vehicle 20 can run. Storage tubes 51 are arranged in the storage modules 7, 9, 11 and 13 so that they are stacked horizontally in sets with one set atop the other as shown in FIG. 4. The back end of each storage tube 51 is held by a suitable mounting arrangement embedded in concrete walls 24, 27; whereas the front ends of the storage tubes are supported in respective bores 53 in the front concrete walls 25 and 26 of each storage module 7, 9, 11 and 13, the walls 25 and 26 facing toward the transport passageway 61 extending through the storage building 5 in the longitudinal direction thereof as indicated by axis 62. The storage tubes 51 are also sealed about their periphery at the bores 53. The storage tubes 51 arranged parallel to one another in one horizontal plane extend in a direction transverse to the storage tubes lying in the next adjacent horizontal plane as shown in FIG. 4. The storage containers 33 holding irradiated nuclear reactor fuel elements are pushed into these storage tubes 51. The openings of the tubes 51 are then tightly sealed with plugs. Referring to FIGS. 3 and 4, the cooling air flowing through the air inlet conduit 45 is caused to flow via branch conduits 47 up through the storage modules 7, 9, 11 and 13 by the chimney effect. This cooling air is continuously directed away from the vertical direction as it passes upwardly through the storage modules 7, 9, 11 and 13 by the layers of storage tubes 51 arranged crosswise as shown. This leads to a swirling effect and to a good heat transfer between the storage tubes 51 and the quantity of cooling air which is available. In this way, the indirect cooling of the storage containers 33 is increased. Referring to FIG. 5 and according to another preferred embodiment of the invention, the storage tubes 51 in horizontal plane c are displaced laterally from the tubes disposed in horizontal plane a so that there is a gap in horizontal plane c directly above each one of the tubes of horizontal plane a. Also, the tubes of plane d are laterally displaced from the tubes of plane b in the same manner as discussed above for planes c and a. This pattern is repetitive and extends up the storage module as shown substantially in FIG. 5. As mentioned above, with the arrangement shown in FIG. 5, the storage tubes of plane a always have an open gap directly above the plane c and so on. The upwardly flowing cooling air is continuously deflected and swirling of the cooling air is increased thereby increasing the contact of flowing air with the outer surfaces of the storage tubes; this improves the transfer of heat to the upwardly flowing cooling air from irradiated fuel elements held within storage containers in the storage tubes 51. An intervention room 63 extends above the rails 15 and 17 of the bridge crane. An auxiliary crane 65 is movably mounted within the room 63. The intervention room 63 is shielded by means of concrete walls. The transport passageway 61 between the mutually adjacent storage modules 7 and 9 on the one side and storage modules 11 and 13 on the other side, can have a narrow width which must only be somewhat larger than the width of the transport mast 31. The storage tubes 51 of the storage modules 7, 9, 11 and 13 are loaded in the direction of their longitudinal axes which is at acute angles .alpha.1 and .alpha.2 to the longitudinal direction 62 of transport passageway 61 (FIG. 1). The storage containers 33 are passed through the concrete walls 25 and 26 of the storage modules 7, 9, 11 and 13 facing the passageway 61. The transport passageway 61 can be configured to have a narrow width because storage tubes 51 in the storage modules are loaded in a direction which forms an acute angle with respect to the longitudinal direction of the passageway 61. By making the passageway 61 narrower, a savings in floor space within the building 5 is realized. It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention, as defined in the appended claims.