JPH032696A - Air borne transportation container for nuclear fuel - Google Patents

Abstract

PURPOSE:To absorb an impact energy effectively by arranging a partition cylinder onto a wooden shock absorber filled layer which is cylindrically shaped and is placed between an outer container and an inner container, concentrically at a intermediate position facing the inner container. CONSTITUTION:A sealed container 3 is housed in an inner container 5. A shock absorbing material 4 for absorption of an impact energy is filled into a gap between the inner container 5 and the sealed container 3. Then, the inner container 5 is housed in an outer container 6 in a manner that a wooden shock absorber material 7 is filled so as to place the inner container 5 at an almost center part of the outer container 6. For example, to a cylindrical wooden shock absorber layer 9 placed between the outer container 6 and the inner container 5, partition cylinders 10 are concentrically arranged at a intermediate positions facing the inner container, and also, to wooden shock absorbing layers 11 and 12, a plurality of partition discs 13 rectangularly and longitudinally crossing the layers 11 and 12, are arranged with a proper spacing. Consequently, when a transporating container falls down by an accident and receives a vertical impact by colliding with a surface of an obstacle, the partition discs 13 make an impact energy absorb into the shock absorbing material 7.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fuel air transportation container used when nuclear fuel materials and radioactive materials are transported by airplane.

[Conventional technology]

When there were no standards for transport containers used when transporting nuclear fuel materials by air, the International Atomic Energy Agency (IAE)
However, in 1975, the United States enacted Public Law 94-79, which prohibited the transport of plutonium by air until a safe transport container that could withstand aircraft accidents was developed. 1978, above I
We have established standards for approval of air transport containers (NUREG-0360), which are stricter than the AEA transport regulations. According to this standard, a collision test is conducted in which a transport container is collided with a flat surface where no yielding occurs at a collision speed of 129 m/s or more. Crush test> Static compression of 32 tons is applied to the transport container through a steel plate having a thickness of 5 marks and a length equal to or greater than the diameter of the transport container. Penetration Test> A transport container is dropped from a height of 3 m onto a conical ring set on a flat surface that will not yield. Slash test> A 1.5 inch long cross-section with a cross section of 5 inches wide and 0.5 inch thick from a height of 46 m into a shipping container tilted at 45 degrees.
Structural steel material is dropped 8m. Fire test: Hold for at least 1 hour under kerosene combustion. Immersion test> It must withstand a series of tests in which it is held at a depth of 90 cm for 8 hours or more. Based on the above specifications, the U.S. government has approved the plutonium air transport container PAT-1 (NUREG0381, NU
REG/C1? -0030,5AND 83-0154
) and FAT-2 type (SAND 8l-0001). However, the plutonium storage capacity of the former is 3.1.
The latter was intended for transporting analytical samples with an extremely small plutonium storage capacity of 150 g, and was not intended for mass air transport of plutonium. To put it simply, the structure of these transportation containers is: a sealed container that houses the nuclear fuel container, an inner container that has the above-mentioned sealed container built in almost in the center with a wooden shock absorber filled with it, and a wooden shock absorber filled with a sealed container. It consists of an outer container with the inner container as described above built in almost the center,
The wooden shock-absorbing material was designed to collapse and absorb the energy upon impact. In order to withstand the severe test conditions imposed on air transport, an invention in which caps lined with polyurethane foam are attached to both ends of the outer container, and the caps are fitted to compensate for the deformation of the outer container wall in the event of a collision. is disclosed in Japanese Unexamined Patent Publication No. 63-222299, and the thickness of the wooden shock absorbing material filled in the inner container and the outer container and the arrangement of its fibers are calculated to absorb the kinetic energy in the event of a collision. It is stated that the cap is made of two steel plates glued together with a flexible epoxy resin adhesive to ensure good hooping.

[Invention or problem to be solved]

The wood that is used as the material for the above-mentioned shock absorbers has different properties depending on whether it is spring wood or autumn wood, so we cut it into relatively small pieces and combine them to make them homogeneous. In order to create a transport container that can be used practically for mass air transport of nuclear fuel materials, etc., it is recommended that a new steel shell be placed in the middle of the wooden impact absorbing material filling layer and dividing the filling layer into the inner and outer parts. It was thought that it might be. However, the results of the experiment showed that during a collision, the steel shell travels like a bullet and actually contributes to the destruction of the transport container. An object of the present invention is to eliminate such drawbacks and to provide a transport container that can be practically used for mass air transportation of nuclear fuel materials and the like.

[Means to solve the problem]

In order to achieve the above object, the nuclear fuel air transportation container of the present invention includes a sealed container containing a nuclear fuel container, an inner container in which the above-mentioned sealed container is built in approximately the center with a shock absorbing material filled with it, and a wooden container filled with a In a nuclear fuel air transport container consisting of an outer container with the above-mentioned inner container built in a shock absorbing material approximately in the center, a cylindrical wooden impact absorbing material filling layer between the outer container and the inner container has a shock absorbing material inside the inner container. A partitioning cylinder is arranged concentrically at an intermediate position facing the container, and a plurality of partitioning circles perpendicular to the longitudinal direction are arranged on the left and right cylindrical wooden impact absorbing material filling layers that touch the end surface of the inner container. It is characterized in that the plates are arranged at appropriate intervals. Preferably, partition rings are attached to both sides of the partition cylinder. It is preferable that the outer container has a laminated structure in which a plurality of thin steel plates are simply stacked on top of each other.

[For use]

When the transport container is subjected to an impact, the partition disc and partition cylinder prevent local deformation of the wooden shock absorber, and the partition disc protects the vertical impact and the horizontal impact. The partition cylinder allows the impact energy to be more efficiently absorbed by the wooden shock absorber. However, since the partition cylinder and partition disk are separate and independent, the bullet effect that contributes to the destruction of the transport container, which was observed in the case of the steel shell, can be avoided. This effect becomes more effective when partition rings are attached to both sides of the partition cylinder. Furthermore, if the outer container is made of a laminated structure in which a plurality of thin steel plates are simply overlapped, plastic buckling will easily occur, and rupture can be avoided.

【Example】

In a first embodiment of the present invention shown in FIG. Materials compliant with reprocessing plant specifications,
This is shown as an example of accommodating a plurality of nuclear fuel containers 2 having different dimensions and shapes. The sealed container 3 that encloses the nuclear fuel container 2 and constitutes the sealed boundary of the transport container 1 is preferably made of a titanium alloy in consideration of lightness, penetration resistance, prevention of plastic deformation, and corrosion resistance against seawater. Titanium alloy has a specific gravity that is 43% lighter than steel and has good seawater corrosion resistance, making it a suitable material for pressure shell materials.If the specified wall thickness is ensured, it can withstand water pressure equivalent to 10,000 meters. I can endure it. This sealed container 3 is housed within an inner container 5. The inner container 5 protects the sealed container 3 from penetrating the transport container 1 and flying out due to impact, and also serves as a fire barrier when exposed to an open flame. It is preferable to use a titanium alloy that is lightweight, strong, and has a high melting point. The gap between the inner container 5 and the sealed container 3 is filled with a cushioning material 4 for absorbing impact energy. The inner container 5 described above is filled with a wooden shock absorbing material 7 so as to be located approximately in the center of the outer container 6. A plurality of vent holes 8 are formed on the surface of the outer container 6 to allow internal air compressed by the impact to escape to the outside. According to the present invention, in the example shown in FIG. The cylinders 10 are disposed concentrically, and a plurality of partition disks 13 perpendicular to the longitudinal direction are appropriately arranged on the left and right cylindrical wooden impact absorbing material filling layers 11 and 12 that are in contact with the end surface of the inner container 5. placed at intervals. When the transport container 1 loaded on an aircraft falls due to an accident and hits the surface of an obstacle and receives a vertical impact, the plurality of partition discs 13 more efficiently transfer the impact energy to the wooden impact absorbing material 7. Let it absorb. Furthermore, when receiving a horizontal impact, the partitioning cylinder 10 allows the impact energy to be more efficiently absorbed by the wooden impact absorbing material 7. However, since the partition cylinder 10 and the partition disk 3 are separate and independent, there is no bullet effect as seen in the case of the steel shell. In the example shown in FIG. 2 showing the second embodiment, partition rings I4 are attached to both sides of the partition cylinder 10, and when the transport container 1 receives a vertical impact, the partition rings ring[
4 has the same function, so that the impact energy is more efficiently absorbed by the wooden shock absorber 7 of the cylindrical wooden shock absorber filling layer 9 between the outer container 6 and the inner container 5. I have to. The outer container 6 has a laminated structure by simply overlapping two thin steel plates 6a and 6b, and is not integrated by adhesive or formed from a single steel plate as in the conventional case. By creating a laminated structure in which the inner and outer layers are simply overlapped, a certain level of structural strength is achieved under normal conditions, but in the event of an impact, each thin fF4
, 6b easily plastically buckles to avoid rupture as much as possible,
Enables absorption of impact energy due to buckling deformation. Although only two thin steel plates are shown in the figure, in the case of an even larger nuclear fuel air transportation container, two or more thin steel plates may be used and a two or more layered fitting structure may be used. Furthermore, if it is possible to generate the above-mentioned constant structural strength and appropriate plastic buckling, the outer container 6 can be divided into two or more parts together with the wooden shock absorbing material 7, and the divided structure can be further divided into a plurality of thin plates. It may be integrated with Generally, the hoop tension stress when internal pressure is applied to a cylindrical shell is twice the meridian stress, so in order to prevent rupture at both ends of the outer container 6 and to efficiently absorb impact energy through plastic deformation at the time of impact. , steel covers 15.15 are fitted to both ends of the outer container 6, and each steel cover 15.15 is fitted to both ends of the outer container 6.
[5 is fitted with a rubber ring 16, so that the rubber ring 1B absorbs the impact energy applied to both ends of the outer container 6 when the transport container 1 falls from a high place, and prevents bruises when handling the transport container.] It's good to plan. In order to prevent the inner container 5, outer container 6, and steel cover 15 described above from bursting upon impact and from being penetrated by protrusions, it is effective to reinforce the surfaces with fiber-reinforced resin. Figure symbol [
7 shows such a fiber-reinforced resin lining layer. In this case, particularly suitable reinforcing fibers are rigid polymeric fibers (such as aramid fibers) that are made of high-strength polymers and are difficult to bend. A lining layer 17 with excellent impact resistance and cut resistance can be obtained by wrapping a woven aramid fiber cloth and adhering it with epoxy resin or the like.

【Effect of the invention】

As can be seen from the above description, the arrangement of the partition cylinder and partition disc in the present invention allows the wooden shock absorber to absorb impact energy more efficiently when the transport container receives an impact. Moreover, since the partition cylinder and partition disk are separate and independent, the bullet effect that contributes to the destruction of the transport container seen in the case of the steel shell does not occur. This method is extremely superior in that it can be used for a wide range of purposes, and is even more effective when attaching partition rings to both sides of a partition cylinder. Furthermore, if the outer container is made of a laminated structure in which a plurality of thin steel plates are simply overlapped, it will easily undergo plastic buckling and absorb impact energy, making it possible to avoid rupture of the transport container as much as possible. Thus, according to the present invention, it is possible to transport at least twice as much plutonium compared to conventional containers, and it is possible to accommodate product plutonium storage canisters and sealed containers from commercial reprocessing plants, which is not necessary with conventional containers. Secondary effects such as eliminating the need for refilling facilities can also be expected.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the nuclear fuel air transport container according to the present invention, and FIG. 2 is a perspective view showing the inside of the nuclear fuel air transport container by partially cutting away the nuclear fuel air transport container of FIG. 1...Nuclear fuel air transport container, 2...Nuclear fuel container 3
... Sealed container, 4... Cushioning material, 5... Inner container,
6... External container, [fa, [lb... Thin steel plate constituting the external container, 7... Wooden shock absorber, 9... Cylindrical wooden shock absorber filled layer, 10. ... Cylinder for partition, 11° 12 ... Cylindrical wooden impact absorbing material filling layer on the left and right, 13 ... Disk for partition, 14 ... Annular ring for partition, 15 ... Made of steel Cover 16...Rubber ring, 17...Fiber reinforced resin lining layer. Patent applicant: Power Reactor and Nuclear Fuel Development Corporation, Rijino Matoyuki Yu

Claims (1)

[Scope of Claims] 1. A sealed container enclosing a nuclear fuel container, an inner container filled with a shock-absorbing material and containing the above-mentioned sealed container approximately in the center, and an inner container filled with a wooden shock-absorbing material as described above. In a nuclear fuel air transport container consisting of an outer container with a built-in container approximately in the center, a cylindrical wooden impact absorbing material filling layer between the outer container and the inner container has a partition at an intermediate position facing the inner container. Cylinders are arranged concentrically, and a plurality of partition disks are arranged at appropriate intervals perpendicular to the longitudinal direction on the left and right cylindrical wooden impact absorbing material filling layers that touch the end surfaces of the inner container. A nuclear fuel air transport container characterized by: 2. Claim 1, in which partition rings are attached to both sides of the partition cylinder.
Nuclear fuel air transport container. 3. The nuclear fuel air transportation container according to claim 1, wherein the outer container has a laminated structure by simply overlapping a plurality of thin steel plates.