Patent Number: 055747590
Section: summary

BACKGROUND OF THE INVENTION Field of the Invention The invention relates to a method for dismantling bulky parts of pressure-vessel fittings of a nuclear plant and for storing the dismantled parts. Such a method is known from Published European Patent Application 0 500 404 A1. In that method, fittings are inserted in a dismantling container which is disposed in a water tank. The fittings are dismantled into predeterminable sizes and introduced into a receiving container that is likewise disposed in the water tank through the use of a dismantling manipulator which can be fixed relative to the dismantling container. Each detached portion must be transported to the receiving container through the use of a lifting appliance, which results in transport distances that are too long and therefore time-consuming. Pressure vessels of nuclear plants are equipped with so-called pressure-vessel fittings for the purpose of receiving fuel assemblies. One bulky part of the fittings is, for example, the core container which fills a large proportion of the pressure-vessel interior, so that when the activated and contaminated core container is exchanged, very large and, due to the shielding requirements, very heavy transport containers, are required for transporting that bulky part. In order to ensure that smaller transport containers can be used, it is necessary to dismantle the bulky parts through the use of known dismantling devices. SUMMARY OF THE INVENTION: It is accordingly an object of the invention to provide a method for dismantling bulky parts of pressure-vessel fittings of a nuclear plant and for receiving the dismantled parts, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known methods of this general type and which preserves short transport distances while ensuring a radiation-proof handling and reception of the bulky parts before and after their dismantling. With the foregoing and other objects in view there is provided, in accordance with the invention, a method for dismantling bulky parts of pressure-vessel fittings of a nuclear plant and for storing the dismantled parts, which comprises setting down a dismantling container for pressure-vessel fittings in a water tank; inserting the pressure-vessel fittings into the dismantling container; introducing a receiving container for the dismantled parts into the dismantling container; fixing a dismantling manipulator relative to the dismantling container; separating the pressure-vessel fittings into predeterminable smaller-size parts; introducing the smaller-size parts into the receiving container; removing the receiving container from the dismantling container; and transferring the parts disposed within the receiving container, within the nuclear plant, into a transport container. Thus, the pressure-vessel fittings to be dismantled are inserted into the dismantling container. The dismantling device is fixed in the immediate vicinity of the dismantling container or to the dismantling container itself. The receiving container for the dismantling products is disposed within the dismantling container, so that short distances have to be covered from dismantling to storage. As soon as the receiving container is filled with dismantled portions, it is inserted into a transport container. The proposed measures ensure intermediately storable or, if required, ultimately storable conditioning as early as within the nuclear plant, with the dismantling and storage operations taking place in a very confined space. In accordance with another mode of the invention, there is provided a method which comprises setting down a bottom part of the dismantling container in the water tank; inserting the pressure-vessel fittings to be dismantled into the bottom part; and pushing a casing part of the dismantling container over the pressure-vessel fittings like a sleeve, and releasably connecting the casing part to the bottom part. In accordance with a further mode of the invention, there is provided a method which comprises introducing the receiving container into a shielding container within the water tank and transferring the receiving container from the shielding container into the transport container outside the water tank. In accordance with an added mode of the invention, there is provided a method which comprises inserting the shielding container together with the receiving container disposed in it, into the transport container. In accordance with a concomitant mode of the invention, there is provided a method which comprises bringing the shielding container and the transport container into position axially-parallel one above the other, removing at least one of a bottom and a cover of the mutually adjacent containers, and passing the receiving container from the shielding container into the transport container with a lifting appliance. Thus, to guarantee a sufficient water covering, a dismantling container being formed of a bottom part and a casing part is used, with the components to be dismantled being moved in from the side before the casing part is pushed over the component in a sleeve-like manner. Radiation-proof handling is also served by the measure calling for the filled receiving container to be introduced into a shielding container as early as within the dismantling container. The receiving container can then be transferred from the shielding container into a transport container outside the water tank. It is also possible to use the shielding container directly, thereby making it possible to employ a thin-walled and therefore light-weight transport container. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in a method for dismantling bulky parts of pressure-vessel fittings of a nuclear plant and for receiving the dismantled parts, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.