Patent Number: 056688431
Section: description

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in detail to the figures of the drawings, which are partly diagrammatic and/or slightly out of shape in order to emphasize specific features, and first, particularly, to FIG. 1 thereof, there is seen a fragmentary view of a storage cage 1 with a baseplate 3, on which a plurality of rectangular casings 4 stand. A fuel assembly 2 symbolized by a cuboid is located in one of the casings 4. The casings 4 are fastened, especially anchored, on the baseplate 3 by non-illustrated provisions. Further positions 11 for non-illustrated casings are represented by broken lines. The baseplate 3 has apertures 5 which lead into the casings 4 and which make it possible for cooling liquid, especially water, that was previously supplied to be capable of flowing off out of the casings 4 when the storage cage 1 is lifted out of a water-filled storage pond. Each casing 4 has an edge region with lateral slots 6 which allow a cooling gas to circulate in the storage cage 1 between the fuel assembly 2 and the casing 4 when the storage cage is located in a non-illustrated container for transport purposes. The casings 4 are connected to one another through the use of straps 12. A connection between a casing 4 and a strap 12 can be made, in particular, by welding. FIG. 2 shows two casings 4 each of which has a relatively complicated, essentially rectangular cross section and each of which is provided with a multiplicity of slots 6. In this case, the slots 6 are disposed in parallel rows on lateral surfaces of the casings 4 in the longitudinal direction. The shape of the casings 4 and the form, number and configuration of the slots 6 are to be matched to the properties of the fuel assemblies 2 which are to be stored in the casings 4. The form, configuration and number of the slots 6 must be determined in each individual instance, in particular with reference to the thermal heat capacity which emanates from the fuel assembly 2 to be stored in the respective casing 4, and with reference to the cooling which has to be provided accordingly for the relevant fuel assembly 2. FIG. 3 shows a storage cage 1 having a multiplicity of approximately rectangular casings 4 in an approximately cylindrical configuration which is itself shrouded by a supporting wall 7. The supporting wall 7 forms a load-bearing part with the non-illustrated baseplate which, in particular, carries the casings 4 and which is to absorb all of the loads to which the storage cage 1 is exposed. The supporting wall 7 has corners which project into the storage cage 1 and in which anchor plates 10 with bores 13 are mounted at the end. A plurality of storage cages 1 can be connected to one another at the anchor plates 10, and moreover a corresponding lifting appliance can engage on the anchor plates 10. Furthermore, it can be seen from FIG. 3 how the storage cage 1 can be introduced into a container 8. The container 8 belongs to a two-part configuration and is surrounded therein by a shielding jacket 14. The container 8 or an actual transport container receiving the container 8 can be sealingly closed, so that radioactive radiation or radioactive fission products emanating from the non-illustrated fuel assemblies disposed in the storage cage 1 cannot escape into the environment. In this particular case, the shielding jacket 14 forms an integral part of an actual transport container which is equipped for transporting fuel assemblies on public highways. FIG. 4 shows how a multiplicity (in this case five) of storage cages 1 can be stacked to form a storage rack for fuel assemblies. The illustrated storage cages 1 essentially correspond in their construction to the construction of the storage cage 1 according to FIG. 3, so that to that extent reference is made to FIG. 3. The storage cages 1 according to FIG. 4 merely each have a multiplicity of anchor plates 10 at each corner disposed one above the other. The storage cages 1 can thus be connected to one another to form a particularly stable rack or can be anchored particularly securely in an associated container. Four of the storage cages 1 are disposed next to one another on a rack plate 17, with the baseplates 3 of the storage cages 1 lying in one plane. The fifth storage cage 1 is placed on one of the four storage cages 1, so that the lowest layer of anchor plates 10 of the storage cage 1 placed on top is congruent with the uppermost layer of anchor plates 10 of the load-bearing storage cage. Anchor plates 10 that touch one another can thereby be fixedly connected to one another. FIG. 5 shows a casing 4 which is especially advantageously incorporated into a storage cage 1 according to the invention. In this case, the casing 4 belongs to a two-layer structure and forms its inner layer. An outer layer of the structure is provided by a supporting wall 7 associated with the casing 4 and connected directly thereto. A storage cage 1 having such casings 4, each of which has its own supporting wall 7, is particularly strong or robust and therefore particularly meets the requirements to be placed on the storage and transport of fuel assemblies 2. A special construction of a fuel assembly 2 is also illustrated in FIG. 5. The fuel assembly 2 has a frame part 9, in which fuel rods 15, each of which contains fissionable material, are fastened. The frame part 9 has spacers 16 on its outside, in order to position it in a stable manner in the casing 4 (or in the nuclear reactor as well). The storage cage of any of the structures described above permits the storage and transport of fuel assemblies from a nuclear reactor both under water in a conventional storage pond and under gas, in particular under blanket gas, in a container that is suitable for transport on public highways. The outlay involved in the transfer of the fuel assemblies is reduced substantially in comparison with the structures known heretofore.