JP2007078609A - Floatation prevention device of storage container for radioactive waste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a floatation prevention device for preventing a storage container from floating up by buoyancy, when making mortar filled in the storage container for radioactive waste stored in a concrete waste block container overflow, and burying the storage container into mortar in the waste block container. <P>SOLUTION: A lock lever 6 is supported rockably centered at a shaft 6a on a bracket 7 fixed to the bottom surface 1b of the waste block container 1, and the lock lever 6 is positioned in a location area of a drum 2 by a restoration force of a reset spring 9. A face facing to the drum 2 of the lock lever 6 is used as an inclined guide face 6b, and the lock lever 6 is pushed and retreated by lowering of the drum 2, and after passing the lock lever 6, the lock lever 6 abuts on the outside surface of a side wall body 2a of the drum 2 by the restoration force of the reset spring 9 and is engaged with a caulking part 2c by a structure when fixing the bottom plate 2b of the drum 2, and the container is restrained by the lock lever 6 thereafter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In the present invention, when a container such as a drum can containing radioactive waste is embedded in mortar, a plurality of containers are stored in an outer container for burying, and the waste container, which is the outer container, is filled with mortar. In particular, the present invention relates to a device for preventing the radioactive waste container from rising, which prevents the container from rising.

  Radioactive waste containing transuranium (TRU) nuclides generated from reprocessing facilities and fuel cycle facilities of MOX fuel processing facilities contains TRU nuclides with a relatively long half-life and a relatively high concentration of radionuclides. It is widely distributed from low to low, and the properties of waste are diverse, including cement, organic matter, metals, etc., and it is generated as the reprocessing business progresses. Increase in volume is expected. Regarding the disposal of radioactive waste containing TRU nuclides, in the “Long-term Plan for Nuclear Research, Development and Utilization (Nuclear Committee, June 1994)”, the concentration standard for all α nuclides is approximately 1 GBq. / T), and for those where underground burial other than shallow underground disposal is considered appropriate, especially for TRU waste, the specific disposal concept should be The policy is to proceed with technical studies so that prospects can be obtained. After that, depending on the concentration of the α nuclide, it has become appropriate to carry out marginal disposal or geological disposal. TRU wastes are classified into those stored in canisters, which are tubular containers made of steel or stainless steel, and those stored in drums. A plurality of canisters or drums are housed in a waste container that is a disposal container as compactly as possible, and placed in a disposal tunnel deep underground for disposal. A waste container containing a plurality of canisters and drums is referred to as a “waste body”.

  This type of disposal container for TRU waste has been proposed to be made of concrete, but there are difficulties in securing impact strength, water tightness, pressure resistance, etc. when it is accidentally dropped during disposal. In view of this, the present applicant has proposed a waste container for geological disposal of pyrogenic TRU-contaminated radioactive waste described in Patent Document 1.

  This geological disposal waste container has a regular hexagonal arrangement of seven primary containers with a fixed shape and containing exothermic TRU-contaminated radioactive waste in a cylindrical steel pressure-resistant container. Remotely welded and sealed so that the steel pressure vessel is provided with an annular or disk-like top plate above the top mirror of the pressure vessel and annular below the bottom mirror of the pressure vessel Alternatively, a disc-shaped bottom plate is provided, and an annular fork receiving portion is provided above the bottom plate.

JP 2000-321397

  The steel pressure vessel requires the work of welding the top mirror after placing the primary container, and also requires precise welding work so that the welded part does not deteriorate due to secular change. In addition, since the steel pressure vessel is required for precise welding, the manufacturing cost of the steel pressure vessel is high.

  On the other hand, because the structure is simple and the manufacturing cost is low, concrete waste containers have been reviewed, and development of waste containers with sufficient impact strength when dropping during disposal work or transportation is progressing . Moreover, in the concrete waste container, after the container is stored, the mortar is poured into the container and filled in the container to seal the radioactive waste, and the mortar is discarded from the container. By overflowing the container and filling the waste container with mortar, the container can be embedded in the waste container with mortar, so that the processing operation is simple and the processing cost can be reduced. .

  However, when filling concrete waste containers with mortar, the following problems may occur. The storage container is filled and stored with radioactive waste without any gap, but since the shape of the radioactive waste is various, the gap formed between the radioactive waste cannot be completely eliminated. Further, since the viscosity of the mortar is high, it takes time until the mortar flows into the small gap, and there is a case where the mortar does not flow into the gap even after the container starts to overflow. For this reason, air remains in the gap, and this air is not quickly discharged, and may remain even when the waste container is filled with mortar. Due to the residual air, the storage container receives buoyancy, which may cause the container to float with respect to the mortar of the waste container. It takes time for the mortar to dry, but if the air does not discharge even in the meantime, the container is dried in a state of floating in the waste container, and the waste container is buried. You might not be able to.

  In order to prevent the storage container from rising, for example, it is conceivable that the mortar is poured in a state in which the storage container is stored in the waste container and pressed from above using an appropriate fixing means. However, after the storage container is stored in the waste container, an operation of fixing the storage container with the fixing means is required, which increases the number of work steps and makes the operation complicated. Moreover, since it is an environment where radioactive waste is handled, workers cannot directly handle the storage container, and the fixing work by the fixing means must be remotely operated or automated, which requires a large-scale device. In addition, depending on the structure of the fixing means, the outer shape of the waste container may be increased, which may require a large storage space for radioactive waste, and may increase the manufacturing cost of the waste container.

  In view of this, the present invention stores a storage container containing radioactive waste in a waste container, and when the storage container is buried in the waste container with mortar or the like and the radioactive material is disposed of, the storage container is An object of the present invention is to provide a device for preventing the rising of a container for radioactive waste that can be surely buried in a mortar without floating.

  As a technical means for achieving the above object, an apparatus for preventing the rising of a radioactive waste storage container according to the present invention includes a waste container storing a storage container for storing radioactive waste, and solidifying the storage container. A radioactive waste that is disposed of in a waste container by filling the material and further filling the waste container with the coagulant overflowing from the container and filling the waste container with the solidified material. In the storage container, a protrusion is formed to project outward at a lower end portion of the storage container, and a locking means that can be engaged with and disengaged from the protrusion is provided on a bottom surface of the waste container. When the container is stored in the container, the protrusion is engaged with the locking means, and the receiving container is restrained by the locking means.

  In the state where the storage container is stored in the waste container, the storage container is restrained by the engagement between the protrusion and the locking means. For this reason, even if the fixing material filled in the container overflows and is filled in the waste container, the container is prevented from rising. As the fixing material, a mortar is used as a representative, and radioactive waste can be sealed and has a fluidity when it is filled in the storage container, and is dried and solidified.

  According to a second aspect of the present invention, there is provided a device for preventing the radioactive waste container from rising, wherein the container is a drum can, and the protruding portion is formed by caulking the bottom plate and the side plate while the drum can is manufactured. It is characterized by the caulking part.

  When a drum can is used as a waste container, when manufacturing the drum can, a plate is formed into a cylindrical shape to form a side wall, and a circular bottom plate having a diameter larger than the outer diameter of the cylinder of the side wall By pushing the inside of the cylinder, the end of the side wall body and the outer peripheral edge of the bottom plate protruding outward from the cylinder are overlapped and crimped. Since the caulked portion is a protrusion protruding outward from the side surface of the drum, the caulking portion is used as a protrusion to be engaged with the locking means.

  According to a third aspect of the present invention, there is provided the apparatus for preventing a radioactive waste container from rising, wherein the waste container is provided with guide means for guiding the container to a position where the container is engaged with the locking means. It is a feature.

  When the storage container is stored in the waste container, the storage container is used by a cargo handling machine such as a crane. Further, since it is difficult to place the waste container at a certain position, the storage container suspended from the material handling and handling machine may not be in a position to be engaged with the locking means with respect to the waste container. . For this reason, the container is gradually lowered while being guided by the guide means so as to be surely engaged with the locking means.

  According to the apparatus for preventing the radioactive waste container from rising according to the present invention, since the container is restrained by the locking means by storing the container in the waste container, the mortar or the like is fixed to the waste container. The container does not float in the state where the material is filled. For this reason, the storage container can be reliably embedded in the fixing material in a state where the fixing material is dry. In addition, since the storage container can be fixed by the operation of storing the storage container in the waste body container, a fixing operation as in the case of fixing the storage container from above is not required, and the work process is not increased. Furthermore, since the waste container is hardly increased in size, the storage space for radioactive waste can be minimized.

  Further, according to the apparatus for preventing the radioactive waste container according to claim 2 from rising, the caulking part formed during the manufacture of the drum can is used as the protrusion by using the drum can in the container. Since it can be used, it is not necessary to separately form a protrusion on the drum, and the cost of the container is not increased. Therefore, the advantage of the concrete waste container that can be manufactured at low cost is not impaired.

  Further, according to the radioactive waste container according to the third aspect of the present invention, the container can be reliably engaged with the locking means by the work of storing the container in the waste container. . Moreover, even if there is an error in the position where the waste container is installed or the positional relationship of the storage container with respect to the waste container, the storage container can be reliably engaged with the locking means.

  Hereinafter, based on a preferred embodiment shown in the drawings, a floating prevention apparatus for a radioactive waste container according to the present invention will be specifically described. FIGS. 3 and 4 show a waste container 1 equipped with a radioactive waste container according to the present invention. FIG. 3 is a front sectional view, and FIG. 4 is a plan view. 5 and 6 are a cross-sectional view taken along line AA and a cross-sectional view taken along line BB in FIG. 3, respectively. The waste container 1 is made of concrete having an appropriate thickness. In this embodiment, the planar shape is formed in a substantially square shape that can accommodate four drum cans 2 that are radioactive waste containers. The waste container 1 is deep enough to embed the drum can 2 to be accommodated, and after the drum can 2 is accommodated, the upper opening is closed by a lid (not shown).

  As shown in FIGS. 3 to 5, the waste container 1 regulates the accommodation position of the drum can 2 and guides the drum can 2 to be positioned at a predetermined accommodation position when the drum can 2 is accommodated. A guide rail 3 is provided. Of these guide rails 3, those located along the inner wall of the waste container 1 are attached to the inner wall 1 a, and those located between the drums 2 are provided upright on the bottom 1 b. The support 4 is provided. Further, as shown in FIG. 3, the guide rail 3 is disposed at a position facing the intermediate portion of the drum can 2 that is housed in the waste container 1. The guide rail 3 has an inclined surface facing the drum can 2, and the guide rails 3 facing each other have an upper side larger than the diameter of the drum can 2 and a lower side substantially equal to the diameter of the drum can 2. ing. As shown in FIG. 3, the drum can 2 is suspended by a suspension device 5 that is moved by a crane (not shown), and is suspended and stored in the waste container 1.

  As shown in FIGS. 1 to 3, a lock lever 6 as a locking means is provided on the bottom surface 1b of the waste container 1 so as to be swingable about a horizontal axis 6a. On the bottom surface 1b of the waste container 1, a pair of roughly L-shaped brackets 7, with one L-shaped leg 7a fixed to the bottom surface 1b and the other leg 7b facing the back, The back surfaces are provided with an appropriate space therebetween, and the shaft 6a is spanned between the upper ends of the leg portions 7b facing the back surfaces. Further, a locking pin 8 is spanned at a portion spaced from the shaft 6a at an appropriate distance, and the locking pin 8 and the lock lever 6 are composed of a torsion coil spring wound around the shaft 6a. A return spring 9 is provided. The rocking region of the lock lever 6 is between the position where the lower end of the lock lever 6 is connected to the drum 2 and the position where the drum can is retracted, and the restoring force of the return spring 9 is The lock lever 6 is urged to swing to a position where it is connected to the drum 2. As shown in FIG. 2, the lock lever 6 is formed in a substantially U shape, and the shaft 6a is inserted through two leg portions of the U shape.

  The surface of the lock lever 6 facing the drum can 2 is formed on the guide surface 6b so that the distance from the surface to the drum can 2 is inclined so that the upper side gradually increases. A portion from the middle to the lower end is located at a position where the drum 2 is occupied. Further, the length from the guide surface 6b to the lower end is set to a vertical surface 6c with an appropriate length.

  On the other hand, when manufacturing the drum can 2, a flat plate is formed in a cylindrical shape to form the side wall body 2a, and a disk having a diameter larger than the outer diameter of the cylinder is inserted from one opening of the cylinder. While aligning the edge of the disk and the edge of the side wall body 2a, winding the aligned edge, caulking the wound portion to form a caulking portion 2c, the disk and the side wall body 2a Stick. Thereby, the bottom plate 2b of the drum can 2 is formed by this circular plate, and the side wall body 2a and the bottom plate 2b are fixed by welding or the like from the inside, the outside, or both the inside and outside. Further, as shown in FIG. 1, the caulking portion 2c protrudes outward from the side wall body 2a, and the caulking portion 2c is a protruding portion that engages with and disengages from the lock lever 6 that is a locking means.

  The lower end of the lock lever 6 is set to be positioned slightly above the caulking portion 2c of the drum can 2 stored in the waste container 1.

  The operation of the apparatus for preventing the radioactive waste container according to this embodiment configured as described above will be described below.

  When the waste container 1 is transported to a predetermined position by a cargo handling machine such as a crane (not shown) and installed, the suspension device 5 suspends the drum can 2 containing radioactive waste and disposes the drum can 2 as a waste body. Move to above the container 1. Next, a crane (not shown) lowers the suspension device 5 and lowers the drum 2. At this time, since the drum can 2 is guided and lowered by the guide rail 3, it is lowered at a predetermined position of the waste container 1.

  On the other hand, the lock lever 6 is in a state of protruding into the occupied area of the drum can 2 under the restoring force of the return spring 9. In the middle of the drum can 2 being guided and lowered by the guide rail 3, the caulking portion 2 c at the lower end of the drum can 2 comes into contact with the guide surface 6 b of the lock lever 6. Since the guide surface 6b is formed as an inclined surface, the lock lever 6 is pushed away from the occupied area of the drum can 2 against the restoring force of the return spring 9 when the drum can 2 is further lowered. For this reason, the drum 2 descends while rubbing the vertical surface 6c of the lock lever 6. When the drum 2 reaches the bottom surface 1b, the caulking portion 2c is positioned below the lower end portion of the lock lever 6. As a result, the lock lever 6 is swung by receiving the restoring force of the return spring 9, the vertical surface 6c is pressed against the outer surface of the side wall 2a of the drum can 2, and the lower end of the lock lever 6 is engaged with the caulking portion 2c. To do. In this state, even if the drum can 2 is to be raised, it cannot be raised due to the engagement between the lock lever 6 and the caulking portion 2c.

  When a predetermined number of drum cans 2 are stored in the waste container 1, mortar as a fixing material is poured into the drum cans 2. When the mortar is filled in the drum can 2, excess mortar overflows from the drum can 2 and flows out into the waste container 1. When the waste container 1 is sufficiently filled with the mortar, the drum 2 is buried in the mortar. At this time, air remains in the drum 2 and attempts to float by receiving buoyancy due to the mortar. However, since the lock lever 6 and the caulking portion 2c are engaged, the drum 2 is prevented from floating. For this reason, the mortar can be dried in a state where the drum can 2 is buried in the mortar, and the drum can 2 is buried in the waste container 1. And this waste container 1 is conveyed to a predetermined storage place, and radioactive waste is discarded.

  In the above-described embodiment, the drum container 2 is used as the storage container. However, the storage container is not limited to the drum can 2 and may have a protrusion that can be engaged with the lock lever 6. For example, other containers may be used.

  According to the apparatus for preventing the radioactive waste container from rising according to the present invention, the apparatus for preventing the floating of the storage container can be functioned upon completion of the operation of storing the storage container in the waste container. For this reason, the remote operation of the radioactive waste treatment can be made simpler, and the waste treatment can be speeded up.

It is a figure which shows the floating prevention apparatus of the radioactive waste storage container which concerns on this invention, and is a figure which shows a part of bottom face of a waste container. It is a top view of the levitation prevention apparatus shown in FIG. It is a figure which cut | disconnects and shows the front of the waste container which comprised the rising prevention apparatus of the radioactive waste storage container which concerns on this invention. It is a top view of the waste container shown in FIG. It is sectional drawing cut | disconnected along the AA line in FIG. It is sectional drawing cut | disconnected along the BB line in FIG.

Explanation of symbols

1 Waste container
1b Bottom 2 Drum can (container)
2a Side wall
2b Bottom plate
2c Caulking part (protrusion part)
3 Guide rail (guide means)
6 Lock lever (locking means)
6a axis
6b Information plane
6c Vertical surface 7 Bracket 8 Locking pin 9 Return spring

Claims (3)

By storing a storage container for storing radioactive waste in a waste container, filling the storage container with a solidified material, and further overflowing the solidified material from the storage container and filling the solid waste container with the solidified material. In a radioactive waste container that disposes of radioactive waste by embedding the container in a waste container,
Projecting outwardly at the lower end of the container to form a protrusion,
Provide a locking means detachable from the protrusion on the bottom surface of the waste container,
When the storage container is stored in a waste container, the projection is engaged with the locking means, and the storage container is restrained by the locking means. Anti-floating device.   2. The radioactive waste container according to claim 1, wherein the container is a drum, and the protrusion is a caulking part formed by caulking the bottom plate and the side plate when the drum can is manufactured. Anti-floating device.   The floating waste container according to claim 1 or 2, wherein the waste container is provided with guide means for guiding the container to a position where the container is engaged with the locking means. Prevention device.

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