JPH0672949B2 - Nuclear fuel air transport container - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a nuclear fuel aviation transport container used when air transporting nuclear fuel materials and radioactive materials by airplane.

[Prior art]

The International Atomic Energy Agency (IAEA) if there is no standard for shipping containers used for air transport of nuclear fuel materials, etc.
The rules for safe transport of radioactive materials created by
In 1975, the United States banned air transportation of plutonium until the development of safe shipping containers to withstand aircraft accidents by public law 94-79, and then in 1978, the standard of approval of air shipping containers stricter than the above IAEA shipping rules. (NUREG-0360) was established. According to this standard, <Collision test> The transport container is collided with a plane where no waviness occurs at a collision speed of 129 m / s or more. <Crush Test> 32 tons of static compression is applied to the transportation container through an iron plate having a thickness of 5 cm and a length equal to or larger than the diameter of the transportation container.
<Penetration test> Drop the transport container from a height of 3 m onto a conical rod placed on a flat surface that does not yield. <Slash> From a height of 46 m to a transport container tilted at 45 °, width is 5 inches, thickness is 0.5
Drop 1.8 m long structural steel with inch cross section. <Fire test> Hold for at least 1 hour under burning kerosene.
<Immersion test> Must endure a series of tests in which water is kept at a depth of 90 cm for 8 hours or more. Based on the above-mentioned standards, the U.S. governmental code is Plutonium air transport container PAT-1 type (NUREG-0361, NUREG / CR-0030, SA
ND83-0154) and PAT-2 type (SAND81-0001) were developed. However, the plutonium storage capacity of the former was limited to .15 kg, and the latter was for transporting an analytical sample with a very small plutonium storage capacity of 150 g, not for mass air transport of plutonium. . The structure of these transport containers can be briefly described as follows: a sealed container containing a nuclear fuel container, an internal container containing the above-mentioned sealed container with a filled wooden shock absorber at approximately the center, and a filled wooden shock absorber. The inner container is made of a material and an outer container which is built in approximately the center thereof, and the wooden impact absorbing material is crushed to absorb energy at the time of impact. In order to withstand the rigorous test conditions imposed on air transportation, caps lined with polyuritan foam are attached to both ends of the outer container so that in case of collision, the caps fit against the deformation of the outer container wall. The disclosed invention is disclosed in Japanese Patent Laid-Open No. 63-222299, and the thickness and the fiber arrangement of the wooden impact absorbing material filled in the inner container and the outer container are designed to absorb the kinetic energy at the time of collision. It is described that it is determined by calculation, and that the cap is made of two steel plates adhered by a flexible epoxy resin adhesive material to ensure good rattling.

[Problems to be Solved by the Invention]

Wood, which is a material of the impact absorbing material described above, has different properties depending on the difference between spring wood and autumn wood, or is made into a homogenized material by combining materials cut into relatively small pieces, and withstands the above-mentioned severe test conditions. In order to make a shipping container that can be put to practical use for mass air transportation of substances, it is advisable to dispose the packing layer inside and outside by newly disposing a steel shell in the middle of the packing layer of the wooden impact absorbing material. I was wondering. However, the results of experiments showed that at the time of collision, the steel shell rushed like a bullet, and rather contributed to the destruction of the shipping container. An object of the present invention is to eliminate such drawbacks and provide a transportation container that can be put to practical use for mass air transportation of truly nuclear fuel substances and the like.

Means for Solving the Problems In order to achieve the above object, a nuclear fuel air transport container of the present invention has a sealed container in which a nuclear fuel container is enclosed, and a sealed container described above with a shock absorbing material filled in approximately the center. In a nuclear fuel air transport container consisting of a built-in inner container and an outer container in which the inner container described above with a filled wooden shock absorber is built in approximately the center, a cylindrical wooden container between the outer container and the inner container is used. A partitioning cylinder is concentrically arranged at an intermediate position facing the inner container in the impact-absorbing material packed layer, and a long column is formed in the left and right cylindrical impact-absorbing material packed layer which is in contact with the end surface of the inner container. It is characterized in that a plurality of partition disks orthogonal to the direction are arranged at appropriate intervals. Preferably, partitioning rings are attached to both sides of the partitioning cylinder.
The outer container preferably has a laminated structure in which a plurality of thin steel plates are simply stacked.

[Work]

When the shipping container receives an impact, the partition disc and the partition cylinder prevent local deformation of the wooden shock absorbers, while vertical impacts are affected by the partition discs and horizontal impacts. The partition cylinder allows the impact energy of the wood to be more efficiently absorbed by the impact energy. However, since the partitioning cylinder and the partitioning disk are independent of each other, it is possible to prevent the bullet effect which is involved in the destruction of the shipping container, which is seen in the case of the steel shell, from occurring. This effect becomes more effective when the partitioning rings are attached to both sides of the partitioning cylinder. If the outer container has a laminated structure in which a plurality of thin steel plates are simply overlapped with each other, the outer container is easily plastically buckled, so that rupture can be avoided.

【Example】

In the first embodiment according to the present invention shown in FIG. 1, the nuclear fuel air transport container 1 is used for commercial purposes so as to be compatible with the equipment of the plutonium storage facility and the transport container handling facility of the commercial reprocessing plant. Material according to the specifications of the reprocessing plant,
It is shown as an example in the case of accommodating a plurality of nuclear fuel containers 2 having dimensions and shapes. The sealed container 3 that encloses the nuclear fuel container 2 and constitutes the sealed boundary of the transportation container 1 is preferably made of a titanium alloy in consideration of lightness, penetration resistance, prevention of plastic deformation, and corrosion resistance to seawater. Titanium alloy is 43% lighter than steel and has good seawater corrosion resistance, so it is a suitable material as a pressure-resistant shell material, and by securing a certain thickness, it is sufficient for water pressure equivalent to 10,000 m. Can bear. The sealed container 3 is contained in the inner container 5. The inner container 5 protects the transport container 1 of the hermetically sealed container 3 from rushing to the outside due to an impact, and also serves as a fire wall when exposed to an open flame.
Similarly, it is preferable to use a titanium alloy that is lightweight, has high strength, and has a high melting point. The space between the inner container 5 and the sealed container 3 is filled with the cushioning material 4 for absorbing impact energy. The above-mentioned inner container 5 is filled with a shock absorbing material 7 made of wood so as to be located substantially in the center of the outer container 6 and is incorporated therein. A plurality of ventilation holes 8 are formed on the surface of the outer container 6 so that the internal air compressed by impact is released to the outside. According to the present invention, in the example shown in FIG. 1, the cylindrical wooden impact absorbing material filling layer 9 between the outer container 6 and the inner container 5 is partitioned at an intermediate position facing the inner container 5. A plurality of partition discs 13 orthogonal to the longitudinal direction are appropriately provided in the left and right cylindrical impact absorbing material filling layers 11 and 12 in which the cylinders 10 are concentrically arranged and which are in contact with the end surface of the inner container 5. It is arranged at intervals. When the transport container 1 loaded on the aircraft falls due to an accident and collides with the surface of an obstacle and receives a vertical impact, the plurality of partition disks 13 more efficiently transfer the impact energy to the wooden impact absorber 7. Try to absorb it. Also,
When a horizontal impact is applied, the partitioning cylinder 10 causes the wooden impact absorbing material 7 to more efficiently absorb the impact energy. However, since the partitioning cylinder 10 and the partitioning disk 13 are independent of each other, there is no bullet effect as seen in the case of the steel shell. In the example of FIG. 2 showing the second embodiment, partitioning rings 14 are attached to both sides of the partitioning cylinder 10 and a plurality of partitioning disks 13 are provided together with the partitioning disks 13 when the transport container 1 receives a vertical impact. The ring 14 has the same function so that the impact energy can be more efficiently absorbed by the wooden impact absorbing material 7 of the cylindrical wooden impact absorbing material filling layer 9 between the outer container 6 and the inner container 5. I am trying. The outer container 6 has a laminated structure in which two thin steel plates 6a and 6b are simply overlapped with each other, and is not integrally formed by adhesion or formed of a single steel plate as in the conventional case.
In this way, the inner and outer two layers are simply laminated to form a laminated structure, which normally exerts a predetermined structural strength, but at the time of impact, the respective thin steel plates 6a, 6b easily plastically buckle and burst. It is avoided as much as possible and it is possible to absorb impact energy due to buckling deformation. Only two thin steel plates are shown in the figure, but in the case of a larger nuclear fuel air transport container, two or more thin steel plates may be used to form a fitting structure of two or more layers. Further, the outer container 6 is divided into two or more parts together with the wooden impact absorbing material 7 if the above-mentioned constant structural strength can cause an appropriate plastic buckling, and the divided structure is further divided into a plurality of thin plates. May be integrated with. Generally, the warp stress when the internal pressure is applied to the cylindrical shell is twice the meridional stress. Therefore, in order to prevent the burst at both ends of the outer container 6 at the time of impact and to absorb the impact energy efficiently by the plastic deformation. , The steel covers 15 and 15 are fitted to both ends of the outer container 6, and the rubber rings 16 are further fitted to the respective steel covers 15 and 15, so that the outer container can fall when the transportation container 1 falls from a high place. It is advisable to absorb the impact energy applied to both ends of 6 with this rubber ring 16 and prevent bruising when handling the shipping container. It is effective to reinforce the surface with the fiber reinforced resin in order to prevent the inner container 5, the outer container 6 and the steel cover 15 from bursting at the time of impact and preventing penetration by the protrusions. Reference numeral 17 in the figure indicates such a fiber-reinforced resin lining layer. In this case, as the reinforcing fiber, a rigid polymer fiber (for example, aramid fiber) having a high-strength polymer and difficult to bend is particularly suitable. A lining layer 17 excellent in impact resistance and cut resistance can be obtained by winding a aramid fiber woven fabric and adhering it with an epoxy resin or the like.

【The invention's effect】

As can be seen from the above description, the arrangement of the partitioning cylinder and the partitioning disk in the present invention allows the wooden impact absorbing material to more efficiently absorb the impact energy when the transportation container receives an impact. It is extremely effective, and since the partitioning cylinder and the partitioning disk are independent of each other, the bullet effect that bears the destruction of the shipping container seen in the case of the steel shell does not occur. It is extremely excellent in that it can be done, and is even more effective when the partition rings are attached to both sides of the partition cylinder. Further, when the outer container has a laminated structure in which a plurality of thin steel plates are simply overlapped with each other, the outer container is easily plastically buckled to absorb impact energy and prevent the transportation container from rupturing as much as possible. Thus, according to the present invention, it is possible to transport at least twice as much plutonium as the conventional container, and it is possible to store the product plutonium storage canister and the sealed container of the commercial reprocessing plant, which is required in the conventional container. Secondary effects such as eliminating the need for refilling facilities can also be expected.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a nuclear fuel air transportation container according to the present invention, and FIG. 2 is a perspective view showing a part of the nuclear fuel air transportation container shown in FIG. 1 ... Nuclear fuel air transport container, 2 ... Nuclear fuel container, 3 ...
... Sealed container, 4 ... Buffer material, 5 ... Inner container, 6 ... Outer container, 6a, 6b ... Thin steel plates that make up the outer container, 7 ...
Wooden shock absorber, 9 …… Cylindrical wooden shock absorber packing layer, 10 …… Cylinder for partitioning, 11,12 …… Cylinder-shaped left and right cylindrical shock absorber packing layer, 13 …… Partitioner Disc, 14 ...
… Partition ring, 15 …… Steel cover, 16 …… Rubber ring,
17 …… Fiber reinforced resin lining layer.

Claims (3)

[Claims] 1. A sealed container containing a nuclear fuel container, an internal container having a sealed shock absorbing material filled therein at approximately the center thereof, and an internal container having a filled wooden shock absorbing material disposed at substantially the center thereof. In a nuclear fuel air transport container consisting of an external container built into a container, a partitioning cylinder is concentrically provided in an intermediate position facing the internal container in a cylindrical wooden impact absorbing material filling layer between the external container and the internal container. A plurality of partition discs orthogonal to the longitudinal direction are arranged at appropriate intervals in the left and right cylindrical impact absorbing material packing layers that are arranged in a circular shape and are in contact with the end surface of the inner container. Nuclear fuel air transportation container characterized by. 2. The nuclear fuel aviation dispatch container according to claim 1, wherein partitioning rings are attached to both sides of the partitioning cylinder. 3. The nuclear fuel air transportation container according to claim 1, wherein the outer container has a laminated structure by simply laminating a plurality of thin steel plates.