JPH0436697A - Transportation and storage container of used fuel and its manufacture - Google Patents

Abstract

PURPOSE:To heighten a heat radiation effect and to realize easy manufacturing not accompanying inconvenience by providing a groove at either a container main body or a mantle and performing welding in a state where a heat-transfer material is fitted in the container main body or the mantle. CONSTITUTION:Plural fins 14 of the heat-transfer material and neutron shielding material 16 are provided between the container main body 10 and the mantle 12, thereby, radioactivity is sealed, and also, decay heat is radiated to the outside. At this time, the groove 18 to insert the fin 14 is provided on at least either the outer plane of the main body 10 or the inner plane of the mantle 12. For example, when the groove 18 is provided on the main body 10, one side terminal part of the fin 14 extending in the longitudinal direction of the container is welded with the inner plane of the mantle 12. Thence, the main body 10 and the mantle 12 are erected, and the fin 14 is inserted as aligning with each groove 18. At this time, dispersion in the size of the fin 14 can be absorbed by inserting to each groove 18. Then, the fin 14 is welded with the main body 10 by a TIG torch 22, however, heat distortion can be suppressed within the range of the groove 18, which prevents a welding position deviated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a container used for safely transporting and storing spent nuclear fuel, etc., and a method for manufacturing the same.

[Conventional technology]

In order to safely transport and store spent fuel in a dedicated container, it is necessary to ensure that the spent fuel's radioactivity is contained within the container, and that gamma rays and neutron rays generated from radioactive materials are reliably shielded. It is necessary to efficiently release the decay heat generated in the process to the outside.

Conventionally, containers for transporting and storing spent fuel have had a double structure in which an outer cylinder is arranged around the container body, as shown in Japanese Patent Application Laid-open No. 62-242896, for example. However, it is generally known that a neutron shielding material and a heat transfer material such as a fin are provided between the two.

FIG. 9 and FIG. 10 illustrate the main parts of the container having the above-mentioned double structure.

In FIG. 9, 90 is a container body, 92 is an outer cylinder,
A fin 94 made of a copper plate or the like is fixed to the surface of the container body 90 by welding, and the outer cylinder 92 is arranged at a position in contact with the heat transfer material 94, and the outer cylinder 92 and the container body 90
A neutron shielding material 96 is filled between the two.

Further, in FIG. 10, fins 94 are fixed to the inner surface of the outer cylinder 92 by welding or the like, and the fins 94 are attached to the container body 9.
An outer cylinder 92 is disposed at a position in contact with the outer surface of 0.

According to such a structure, the neutron shielding material 96 shields neutron beams, etc., and decay heat, etc. generated from the radioactive material in the container is released to the outside via the fins 94. In the container described above, the fins 94 are welded to either the container body 90 or the outer tube 92, but only contact the other. Moreover, since each fin 94 has some shape error, it is difficult to uniformly contact these fins 94 over the entire length and circumference of the container.
In reality, gaps often occur locally. For this reason,
Sufficient heat conduction cannot be obtained, making it difficult to achieve good heat dissipation.

On the other hand, when attempting to weld the fins 94 to both the container body 90 and the outer cylinder 92, long automatic remote welding must be performed in a narrow space, which poses a problem in workability.

Moreover, as the welding causes thermal strain on the fins 94, the welding position shifts during welding, making the work more difficult, and it is difficult to perform good welding over the entire length of the container. If a defect occurs, it is difficult to repair because there is only enough space to put one hand in, so it is difficult to apply simple and general welding methods, and welding methods that have fewer defects and are more reliable (e.g. advanced profiling control, etc.) must be used, which is also a factor in high costs.

In view of these circumstances, an object of the present invention is to provide a spent fuel transportation/storage container that enhances the heat dissipation effect and can be easily manufactured without any inconvenience, and a method for manufacturing the same. - [Means for Solving the Problems] The present invention includes a container body and an outer cylinder disposed around the container body, and a plurality of heat transfer materials and neutron shielding materials are provided between the two. In a container for transporting and storing fuel, a groove is provided on at least one of the outer surface of the container body and the inner surface of the outer cylinder, and the end of the heat transfer material is fitted into the groove. is welded to both the container body and the outer cylinder.

The present invention also provides a method for manufacturing the container in which one end of the heat transfer material is welded to either the outer surface of the container body or the inner surface of the outer cylinder, and the other end of each heat transfer material is welded to the other. After the other end of the heat transfer material is fitted into this groove, the member provided with this groove and the heat transfer material are welded together.

[For production]

According to the above configuration, since the heat transfer material is positioned by fitting into the groove, the heat transfer material is hardly displaced even if it is heated during welding.

〔Example〕

FIG. 1 and FIGS. 2(a) and 2(b) show a spent fuel transportation/storage container in a first embodiment of the present invention.

As shown in FIGS. 2(a) and 2(b), this container has a double structure consisting of a cylindrical container body 10 and an outer cylinder 12 arranged around this container body 10. . and,
As shown in FIG. 1, both ends of a plurality of fins 14 made of copper plates or the like are welded to the outer surface of the container body 10 and the inner surface of the outer cylinder 12, and resin, etc. A method for manufacturing this container will be described with reference to FIGS. 3 to 5.

First, one end of the fin 14 extending in the longitudinal direction of the container is welded to the inner surface of the outer cylinder 12.
A groove 18 having a width that allows the fin 14 to fit into the outer surface of the groove 18.
is provided in the longitudinal direction. Here, the outer cylinder 12 is preferably made by bending a plate material into a cylindrical shape and welding it in the longitudinal direction, and the container body 10 may be made of a single piece or by bending a plurality of plate materials into a cylindrical shape. A multi-layered structure formed by sequentially stacking layers on the outside may also be used.

Further, it is preferable that the width of the groove 18 is set slightly larger than the thickness of the fin 14, and in this embodiment, the difference in dimension between the two is approximately 0.5 mm.

Next, as shown in FIG. 3, the container body 10 and the outer cylinder 12 are stood up, and the fins 14 are inserted into the grooves 18 in the longitudinal direction while aligning the fins 14 with each groove 18. As a result, the outer cylinder 12 is placed around the container body 10, and the other end of the fin 14 fixed to the container body 10 is fitted into the groove 18. At this time,
Even if there is some variation in the dimensions of the fins 14, the variation is absorbed by the fins 14 being fitted into the respective grooves 18.

Next, the entire container is laid down, and as shown in FIGS. 4 and 5, the T
The IG torch 22 is inserted between the container body 10 and the outer cylinder 12, and while the guide 24 fixed to the moving arm 20 is applied to the boundary between the fins 14 and the container body 10, the moving arm 20 is moved along the longitudinal direction of the container using a manipulator. By moving in the direction, the fins 14 and the container body 10 are joined by TIG welding. Thereafter, by filling the space between each fin 14 with the neutron shielding material 16, a structure as shown in FIG. 1 and FIGS. 2(a) and 2(b) is obtained.

Here, during the above welding, the guide 24 is connected to the TIG torch 2
It plays the role of accurately aligning the position of 2 with the boundary portion and keeping the arc length constant.

Also, during this welding, the fin 14 tries to displace due to thermal strain, but since the fin 14 is restrained by fitting into the groove 18, it can only be displaced within the range of this groove 18, and therefore the welding position almost does not shift.

As described above, in this container, the grooves 18 are provided in the container body 10, and the fins 14 and the container body 10 are welded with the fins 14 fitted into the grooves 18. 14 positional deviation hardly occurs,
Therefore, remote automatic welding can be easily performed without any inconvenience even with a simple device such as the TIG welding device described above. In addition, in this way, the fins 14 are connected to the container body 10 and the outer cylinder 1.
By welding to both sides, the heat dissipation effect of the entire container is greatly improved.

A second embodiment is shown in FIG. Here, a groove 18 is provided on the inner surface of the outer cylinder 12. In this case as well, first the container body 10
By welding one end of the fin 14 to the outer surface of the fin 14, and then fitting the other end of the fin 14 into the groove 18 and welding it to the outer cylinder 12, the container can be easily opened as in the first embodiment. can be manufactured.

Thus, in the present invention, the groove may be provided on either side of the container body or the outer cylinder. Further, it may be provided on both sides.

A third embodiment is shown in FIG. Here, the present invention is applied to a container body 10 having a multilayer structure. That is, here, an outer layer 102 in which grooves 18 have been processed in advance is disposed around the inner layer 101 of the container body 10, and the fins 14 are fitted into the grooves 18 of the outer layer 102.
This fin and the outer layer 102 are welded together.

According to such a configuration, the inner layer 101 that constitutes the main part of the container body 10 and the outer layer 102 to which welding is performed are separate bodies, so even if the fins 14 are welded, this welding will not occur on the inner layer 101. does not directly lead to stress generation. Therefore, when the inner layer 101 of the container body 10 is formed, heat treatment such as annealing is completed first, and then the outer layer 102 can be provided and the fins 14 can be welded.

That is, in this configuration, the fin 1 has relatively poor heat resistance.
Since it is not necessary to heat-treat each fin 14, thermal deformation of the fin 14 due to this can be avoided, which is more convenient.

Note that this structure can also be applied when the groove 18 is provided on the outer cylinder 12 side. That is, the inner surface of the outer cylinder 12 may be provided with a layer in which grooves are formed in advance.

A fourth embodiment is shown in FIG. Here, a plurality of guide rails 30 having grooves 18 are fixed at appropriate positions on the circumferential surface of the container body 1o with screws or the like, and the fins 14 are fitted into the grooves 18 of the guide rails 30. Even in such a configuration, heat treatment of the entire container including the fins 14 can be avoided by heat-treating the container body 10 in advance and then attaching the guide rail 30.

Note that the guide rail 3o may be attached to the inner surface of the outer cylinder 12.

〔Effect of the invention〕

As described above, according to the present invention, a groove is provided in at least one of the container body and the outer cylinder, and welding is performed with the heat transfer material fitted into the groove. By absorbing dimensional variations in the heat transfer material and regulating the positional shift of the heat transfer material during welding, this heat transfer material can be welded to the container body and outer cylinder in a simple manner. This has the effect of improving heat dissipation performance while reducing costs.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of part A in FIG. 2(a), FIG. 2(a) is a perspective view showing the step of inserting the fin into the groove of the spent fuel body in the first embodiment of the present invention, and FIG. The figure is a partially cross-sectional side view showing the process of welding the fins to the vessel body in the same container, Figure 5 is a cross-sectional front view showing the same process, and Figure 6 is a spent fuel transportation/storage container in the second embodiment. 7 is a cross-sectional front view showing the main parts of the spent fuel transport/storage container in the third embodiment. FIG. 8 is a cross-sectional front view showing the main parts of the spent fuel transport/storage container in the fourth embodiment. FIGS. 9 and 10 are cross-sectional front views showing the main parts of a conventional spent fuel transportation/storage container. DESCRIPTION OF SYMBOLS 10... Container main body, 12... Outer cylinder, 14... Fin (insulation material), 16... Neutron shielding material, 18... Groove, 22... TIG torch. Figure 3

Claims (1)

[Claims] 1. Transport and storage of spent fuel, comprising a container body and an outer cylinder arranged around the container body, with a plurality of heat transfer materials and neutron shielding materials provided between the two. In the container, a groove is provided in at least one of the outer surface of the container main body and the inner surface of the outer cylinder, and with the end of the heat transfer material fitted into the groove, the heat transfer material is connected to the container main body and the outer cylinder. A spent fuel transport/storage container characterized in that both sides of the cylinder are welded. 2. A method for manufacturing a spent fuel transportation/storage container, comprising a container body and an outer cylinder disposed around the container body, with a plurality of heat transfer materials and neutron shielding materials provided between the two. Then, one end of the heat transfer material is welded to either the outer surface of the container body or the inner surface of the outer cylinder, and a groove into which the other end of each heat transfer material can be fitted is provided on the other side, and a groove is provided in the groove. A method of manufacturing a spent fuel transportation/storage container, which comprises: inserting the other end of the heat transfer material, and then welding the member provided with the groove and the heat transfer material.