RU2195724C2 - Concrete container for long-time storage and shipment of radioactive wastes and method for concrete cover manufacture and for container stacking - Google Patents

Abstract

FIELD: nuclear power engineering; storage and shipment of loose and solidified liquid wastes. SUBSTANCE: concrete container has case and cover set on depression in top part of case; the latter is octahedral prism with alternating narrow and wide edges. Narrow edges bear depressions to receive gripping mechanisms and external part of bottom has projection in its center whose outer dimensions are smaller than size of depression in upper part of case for joining cases of containers when stacking them. Container cover is provided with taper hole, its lower-diameter end being on top; case-to-cover clearance is sealed with concrete. Distance between upper edge of case and cover is smaller than bottom projection height. In case of horizontal stacking containers are placed right against each other by joining adjacent containers over wide edges at the same time organizing process channels by narrow edges of containers, These channels are used to receive gripping mechanisms. In case of vertical stacking containers may be piled with bottom projection of upper container being inserted in depression formed between upper edge of case and lower-container cover. Appropriate height of bottom projection enables using fork trucks for stacking the containers. Used as form for concrete cover manufacture is container case whose depression meant to receive cover serves as supporting surface. Such design makes it possible to obtain removable cover and to precisely align supporting surfaces of cover with those of case. Case-to-cover locks facilitate cover installation on case in working position. EFFECT: enhances operating reliability and safety, reduced space requirement, facilitated handling of containers in stacking them for storage. 7 cl 9 dwg

Description

 The invention relates to nuclear engineering, in particular to the storage and transportation of solid bulk and solidified liquid radioactive waste.

 A container for storing and transporting fuel rods is known, comprising a housing, a cassette with cells for receiving fuel rods installed in the housing, a device for sealing the lid on the housing, the device and the lid being attached to the housing using bolts (US Pat. No. 5,406,601, 1994). However, during long-term storage of this container due to oxidation and adhesion of metals, its threaded connections become one-piece.

 A metal-concrete container for transporting and storing spent nuclear fuel is known, comprising a body welded from 2 shells, the annular space between them filled with concrete and reinforcement, and the lid and rigging units located on the body (A. Zubkov and others. "Metal-concrete container for storage and transportation of spent nuclear fuel RBMK ", - J. Heating Engineering, 1996, 11, p. 40-44). However, this design is low-tech and difficult to manufacture.

 Closest to the claimed technical solution is a container for storing and transporting spent fuel assemblies, comprising a housing on which guides for wedges are evenly placed, a lid made under a recess in the upper part of the housing and secured with wedges on the housing (RF patent 2154316, publ. 10.08. 2000, BIPM 22).

 However, in the manufacture of such a container, machining of the joints of the lid with the body and wedges is required, as well as the cutting of the weld when opening. The lifting units and shock absorbers of this container are made of metal, so corrosion occurs during long-term storage, which reduces the strength characteristics of the container. In addition, the rigging nodes of the container protrude beyond its body, and the container has a cylindrical shape, so they take up a lot of space when stacking.

 A known method of manufacturing a container described in French patent 2445590 (publ. 25.07.80), which is the closest to the claimed method. In the known method, concrete is poured on top of the loaded fuel from above, and a lid in the form of a cork is formed in the container. The formwork for the manufacture of the lid in this method is the body of the container itself. Since the operation is carried out with waste or fuel loaded in the container, this reduces the safety of operation of the container. In addition, the formation of the lid in the form of a concrete cork may not provide the necessary tightness of the container and does not allow the reuse of such a lid.

 Closest to the claimed method of stacking containers is the method described in US patent 5753925 (publ. 19.05.98). According to the patented method, the containers are placed in storage with the formation of channels between them. These channels serve for the passage of cooling gas, while the containers must be located at a certain distance from each other. In the case of a low level of radioactivity of the waste to be stored, when its forced cooling is not required, the requirements for the compactness of their disposal and transportability are more important. The known method cannot satisfy these requirements.

 The proposed inventions solve the problems of improving the reliability and safety of operation of containers, the economy in their manufacture, as well as the compactness and transportability of containers when stacked for storage.

 In the proposed concrete container for storing radioactive waste containing a housing, a cover made under a recess in the upper part of the housing and closed with wedge locks, to solve the tasks, the housing is made in the form of an octagonal prism with alternating narrow and wide faces. On narrow faces, recesses are made for grippers, and in the center of the outer part of the bottom there is a protrusion, the outer dimensions of which are smaller than the dimensions of the recess in the upper part of the body for interfacing the container bodies when they are installed on top of each other. The lid of the container is equipped with a conical hole located with a smaller diameter to the outside, with a stopper in which the anchor bolt is located, and the gap between the lid and the body is sealed with concrete. The distance between the upper edge of the housing and the cover is less than the height of the protrusion on the bottom. The supporting surface of the cover can be made in the form of arches. To facilitate the installation of the cover on the housing, latches can be installed between them.

 Due to the fact that the case is octagonal, this allows for horizontal stacking of containers to install them closely, joining adjacent containers along wide faces with the formation of technological channels between the narrow faces of the containers. Well-formed channels are used for lifting devices. If necessary, vertical stacking of the containers can be mounted on top of each other, with the protrusion on the bottom of the upper container is installed in the recess formed between the upper edge of the housing and the lid of the lower container. Performing a protrusion on the bottom of the container of the appropriate height allows the use of forklifts when stacking them.

 A distinctive feature of the proposed method for manufacturing a concrete lid for a container is that the container body for forming the lid is used as the formwork, while the existing recess in the housing under the lid is used as its supporting surface. This allows the lid to be removable, and the bearing surfaces of the lid are precisely mated with the bearing surfaces of the housing. Thus, it is possible to achieve a uniform fit of the cover to the housing.

 The presence of clamps between the lid and the housing makes it easy to install the lid on the container body in the working position. The combination of the protrusion on the bottom of the housing with the specified recess will prevent the possibility of sliding of the upper container.

 Distinctive features of the proposed solutions make it possible to refuse the use of protruding lifting units for stacking, which can be subject to corrosion and deformation, to install containers closely in horizontal and vertical planes, to achieve maximum uniform adherence of the lid to the body, to reduce contact with radioactive waste by filling the container with concrete through the hole in the lid, which is a technical result in the implementation of the invention.

 The invention is illustrated by drawings.

 In FIG. 1 shows a general view of the container; figure 2 - a view of figure 1; in FIG. 3 - view B in figure 1; figure 4 is a section bb in figure 2; in Fig.5 is a section GG in Fig. 2; in FIG. 6 - section DD in figure 2; Fig.7 - traverse for transporting the cover; on Fig - stacking containers, top view; Fig.9 is a view of E in Fig.8.

 A concrete container for long-term storage of radioactive waste contains a housing 1, a cover 2, wedges 3, guide parts 4 under the wedges on the housing 1, guide parts 5 under the wedges 3 on the cover 2, the bearing surfaces of the cover 2 can be made in the form of arches 6, in the cover there is a conical hole 7 for filling the empty space of the container after loading radioactive waste into it with special concrete, depending on the type of radioactive waste and a plug 8 with anchor 12, which improves radiation safety and immobilization functions uu container nipple 9 for supplying air in the test container for leaks, as well as anchors 23 for transporting the cover.

Case 1 has four recesses 10 on narrow faces for a standard gripping device, and the bottom of the case has a protrusion 11, the outer dimensions of which are smaller than the dimensions of the recess 13 in the upper part of the case
The case and cover can be made of hematite fiber-reinforced concrete, due to its application, radiation protection is improved and, as a result, radiation safety is improved.

 The lids 2 are molded in the housing 1 individually for each container until the waste is loaded into them. A formwork is installed in the housing 1, for example, in the form of a table (not shown) for forming the cover 2. The formwork for forming the supporting surface of the cover 2 in the form of arches 6 is the supporting surface of the recess 13 under the cover in the housing 2. After the concrete has set and shrunk, the cover 2 can be removed from the housing.

 After filling the container with waste, the lid 2 relative to the housing 1 is mounted on three latches 14 with the help of a traverse 15 and secured with wedges 3. The wedge locks formed by the wedges 3 are locked in pairs with a calibrated force. To protect the wedges 3 from falling out, they are fixed by stoppers 22, which are welded to the guide parts 4 on the housing 1.

 Transportation and installation of the cover 2 is carried out using a traverse 15, which has: two embedded pins 16 to ensure transportation of the cover 2; two hydraulic cylinders 17 for locking with a calibrated force of pairwise opposed wedges 3; two levers 18 for returning the rods of the hydraulic cylinders 17 to their original position; two fittings 19 for supplying the working fluid to the hydraulic cylinders 17 through hoses 20 from the hydraulic station 21.

 For long-term storage of a container filled with radioactive waste, a lid 2 is installed and wedge locks formed by wedges 3 are locked, the container is concreted through mixtures 7 in the lid 2 with mixtures depending on the type of waste and storage conditions of the containers. After that, the hole 7 is filled with the same mixture, the cover 8 is installed in it, all the holes in the cover 2 are filled, except for the hole with the nipple 9, as well as the gap between the cover 2 and the housing 1 with concrete on expandable gypsum-alumina cement. Then test the container for leaks through the nipple 9, after which this hole is also filled with concrete. The container is ready for long-term storage.

 Prepared containers are stacked, installing them closely, joining along wide lateral faces. In this case, between the narrow faces on which the recesses 10 are made for grippers, technological channels are formed. When performing the protrusion 11 on the bottom of the appropriate height, it provides a technological gap between the container and the floor, as well as between the containers in a vertical plane. The execution on the body 1 of the container of the recesses 10 on the narrow edges and the protrusion 11 on the bottom allows you to transport containers with the help of load gripping devices, and using forklifts.

Claims (7)

 1. A concrete container for long-term storage and transportation of radioactive waste, comprising a housing, a cover made under a recess located in the upper part of the housing and secured with wedge locks, characterized in that the housing is made in the form of an octagonal prism with alternating narrow and wide faces, moreover recesses for gripping devices are made on narrow faces, and in the center of the outer part of the bottom of the case there is a protrusion, the outer dimensions of which are smaller than the dimensions of the recess in the upper part of the body, in addition, the cabinet is equipped with a conical hole located with a smaller diameter to the outside, with a stopper in which there is an anchor bolt, and the gap between the cover and the body is sealed with concrete, and the distance between the upper edge of the body and the cover is less than the height of the specified protrusion on the bottom.  2. The container according to claim 1, characterized in that the supporting surfaces of the lid are made in the form of arches.  3. The container according to claim 1, characterized in that the height of the protrusion on the bottom of the housing provides technological clearance for the fork of the forklift.  4. The container according to claim 1, characterized in that there are latches between its body and the lid.  5. A method of manufacturing a cover of a concrete container, in which the container body is used as a formwork, characterized in that the recess under the cover in the housing is used as the supporting surface of the formwork.  6. A method of stacking containers, in which the containers are positioned to form channels between them, characterized in that adjacent containers are mounted close to each other, joining them along the wide side faces of the housing, while technological channels for gripping devices are formed between the narrow faces.  7. The stacking method according to claim 6, characterized in that when the containers are installed on top of each other, the protrusion on the bottom of the upper container is installed in a recess formed between the body and the lid of the lower container.

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