JPH0242396A - Radioactive material transport container - Google Patents

Abstract

PURPOSE:To display the buffering operation of a buffer body by providing support members in special shapes to the bottom part of the transport container and making the support members project out in the radial directions of the transport container and buckling if the transport container is fallen. CONSTITUTION:A neutron shield body 3 is provided at the periphery of a sealed container 1 containing a radioactive material and its lid 2, and the buffer body 4 for fall shock absorption is provided outside the shield body. Further, an external cylinder 6 is provided around the buffer body 4, many support members 7A are fixed between the bottom part of the external cylinder 6 and the bottom part of the container 1, and an angle gamma is set larger than an angle theta. Consequently, even when the transport container is fallen in the horizontal state and even when it is fallen at the angle theta from the horizontal state, the respective members 7A buckle outward in the radial directions of the container 1. The buffer body 4 is never impeded from deforming by being pushed out to the outer periphery and displays the normal buffering effect.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objective of the Invention) (Industrial Application Field) The present invention relates to a radioactive material transport container used for transporting radioactive material such as nuclear fuel for light water reactors and breeder reactors.

(Prior art) In general, containers for transporting radioactive materials such as nuclear fuel for light water reactors and breeder reactors, especially those whose contents have high specific radioactivity (3 to 1 transport containers, do not have the structural strength of each part of the container required during normal handling). Furthermore, even under various conditions assumed at the time of an accident, it must be maintained in such a state that there is no possibility of the line color rate, leakage rate, or criticality being exceeded.

Among the test conditions that simulate such an accident, one of the strictest conditions is the structural strength of the container, which requires a 9m drop test in which the container is dropped naturally onto a rigid floor from a height of 9m. VI of various shapes and materials to withstand impact
An impactor is provided.

Figure 4 shows a typical structure of a radioactive material transport container. In Figure 4, numeral 1 indicates radioactive materials such as nuclear fuel for light water reactors and breeder reactors inside? 1 is shown. This sealed container 1 is covered with a lid 2, and this lid 2 is fixed to the sealed container 1 with bolts (not shown).

A neutron shield (such as resin) 3 is provided around the sealed container 1 and the lid 2, and a shock absorber 4 for absorbing drop shock is provided outside of the neutron shield 3.

A partition plate (intermediate cylinder) 5 is provided between the buffer body 4 and the neutron shield 3, and an outer cylinder 6 that forms the outer shell of the entire container is provided around the buffer body 4.

Here, there are various examples of II structures for the buffer body 4, such as those using water conduits (such as balsa wood), those using laminated aluminum tubes, and those using a metallic toroidal shell.

(Problem to be Solved by the Invention) Since the above-mentioned buffer body 4 pursues only a buffering function, when the sealed container 1 is placed upright to put radioactive substances into the sealed container 1, My own weight! 1. A support member 7 is provided to prevent the support member 7 from acting on the enclosure body 4.

Conventionally, a straight vibrator or cylinder has been used as the support member 7, but the support member 7 may buckle toward the central axis of the transport container during the 9 m drop test.

In this case, since the lower end of the support member 7 is fixed to the outside 56, the shock absorber 4 is crushed in the axial direction, and its movement to push outward is hindered, and there is a risk that the normal shock absorbing function will not be exhibited.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a radioactive substance transport container in which the buffering effect of the buffer body is not hindered even when the support member is buckled.

[Structure of the invention]

(Means for Solving the Problems) The radioactive nuclear fuel transport container according to the present invention includes a sealed container for storing radioactive materials such as spent nuclear fuel, a shielding body surrounding the sealed container, and a shielding body that covers the outside of the shielding body. A cushioning body for enclosing, a partition plate for partitioning between the cushioning body and the shielding body, an outer cylinder for wrapping around the outside of the cushioning body, and a support member for connecting the bottom of the sealed container and the bottom of the outer cylinder. In the radioactive material transport container, at least half of the supporting member protrudes outward in the radial direction of the sealed container beyond the part fixed to the sealed container, and the supporting member is located between the center of gravity of the transport container and the outer periphery of the bottom of the outer cylinder. It has a portion extending outward in the radial direction of the transport container at an angle γ larger than the angle θ formed by a line connecting the transport container with the center line of the transport container.

(Function) At least half of the support member protrudes outward in the radial direction of the sealed container beyond the part fixed to the sealed container, and a line connecting the center of gravity of the transportation container and the outer circumferential corner of the bottom of the outer cylinder is A radially outwardly extending portion of the transport container is defined by an angle γ greater than the angle θ with the center line of the transport container.

Therefore, even if the transport container falls at a corner (drops while tilted by an angle θ from the horizontal state of the transport container), the support member will not buckle in the direction of the central axis of the transport container (
The transport container protrudes outward in the radial direction and buckles.

As a result,! The deformation in which the IIfi body is pushed out toward the outer periphery is not hindered, and a normal buffering effect can be exerted.

(Example) An example of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 is a sectional view showing an embodiment of a radioactive material transport container according to the present invention. In FIG. 1, reference numeral 1 designates a sealed container in which an I21 bamboo material such as nuclear fuel for a light water reactor or a breeder reactor is stored.

The lid 2 of the sealed container 1 is V! The lid 2 is fixed to the sealed container 1 with bolts (not shown).

A neutron shield (resin or the like) 3 is provided around the sealed container 1 and M2, and a shock absorber 4 for absorbing drop shock is provided outside of the neutron shield 3.

As the buffer body 4, wood (such as balsa wood), a stack of aluminum tubes, a metal toroidal shell, etc. are used.

A partition plate (intermediate cylinder) 5 is provided between the buffer body 4 and the neutron shield 3, and an outer cylinder 6 that forms the outer leg of the entire container is provided around the buffer body 4.

A large number of support members 7A are provided between the bottom of the outer cylinder 6 and the bottom of the sealed container 1 to prevent the weight of the sealed container 1 from acting on the buffer body 4. One end of these support members 7A is fixed in large number to the bottom of the sealed container 1 in a circumferential manner, and the other end is fixed to the bottom of the outside 1-16. Each support member 7A has a pipe structure, for example.

The middle part of each support member 7A projects outward in the radial direction of the sealed container 10 from the part fixed to the sealed container 1, and the part on the sealed container 1 side is connected to the center of gravity G of the transportation container and the outer periphery of the bottom of the outer cylinder 6. The line connecting the side angle A extends from the bottom of the sealed container 1 outward in the radial direction of the transport container at an angle γ larger than the angle θ formed with the center line of the transport container.

A portion of the support member 7A on the outer cylinder 6 side extends radially inward of the sealed container 1 and is fixed to the bottom of the outer cylinder 6.

Next, the operation of the above embodiment will be explained.

First, if the transport container falls 9 meters while remaining horizontal, the intermediate portions to each support member 7 protrude outward in the radial direction of the sealed container 1 than the fixed portions to the sealed container 1. The member 7A is prevented from buckling radially outward of the sealed container and buckling radially inward.

Furthermore, even if the transport container falls at an angle O from the horizontal state (corner drop), the portion of each support member 7A on the sealed container 1 side will Each support part '4A7△ extends from the bottom of the container 1 to the outside in the radial direction of the transport container, so that each support part '4A7△ is prevented from buckling radially outward and buckling radially inward.

Therefore, the deformation of the cushioning body 4 that is pushed out toward the outer periphery is not hindered, and a normal cushioning effect can be exhibited.

FIG. 2 is a sectional view showing another embodiment of the present invention.

Each support member 7B is bent multiple times, and the sealed container 1
The width O that projects outward in the radial direction is 24t! The width O that projects inward is 24t! formed for a longer period of time.

This embodiment also has the same effects as the previous embodiment.

FIG. 3 is a new view showing yet another embodiment.

The support member 7C is made of bellows. This bellows may be cylindrical or may be divided into a plurality of pieces in the circumferential direction.

At least half of this support member 7C protrudes outward in the radial direction of the sealed container 1 beyond the fixed portion to the sealed container 1, and extends toward the center of gravity G of the transportation container and the outer peripheral side corner of the bottom of the outer cylinder 6. and has a portion extending outward in the radial direction of the transport container at an angle γ larger than the dimension θ, in which a line connecting the transport container is the center line of the transport container.

This embodiment also has the same effects as the previous embodiment.

〔Effect of the invention〕

In the radioactive material transport container according to the present invention, at least half or more of the support member protrudes outward in the radial direction of the sealed container beyond the fixed portion to the sealed container, and the support member is located between the center of gravity of the transport container and the bottom of the outer cylinder. Because it has a part that extends outward in the radial direction of the transport container at an angle γ that is larger than the angle γ that the line connecting the outer circumferential side corner of buckling in the direction is prevented. As a result, the deformation in which the buffer body is pushed out toward the outer periphery is not hindered, and the normal <t M i! It is possible to produce an economical transportation container, which can exhibit the i effect, improve reliability, and reduce the amount of B of the cushioning material.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of a radioactive material transport container according to the present invention, FIG. 2 is a cross-sectional view showing another embodiment of the present invention, and FIG. 3 is a cross-sectional view showing yet another embodiment of the present invention. FIG. 4 is a sectional view showing a conventional radioactive material transport container. DESCRIPTION OF SYMBOLS 1... Sealed container, 2... Lid, 3... Neutron shield, 4... Buffer, 5... Partition plate, 6... Outer cylinder, 7A. B. 7C...Supporting member.

Claims (1)

[Claims] A sealed container for storing radioactive materials such as spent nuclear fuel, a shielding body surrounding the sealed container, a buffer body surrounding the outside of the shielding body, a partition plate separating the buffer body and the shielding body, and the above-mentioned In a radioactive substance transport container comprising an outer cylinder enclosing the outside of a buffer body and a support member connecting the bottom of the sealed container and the bottom of the outer cylinder, at least half of the support member is part of the sealed container. The container protrudes radially outward from the fixed part of the sealed container, and is transported at an angle γ that is larger than the angle θ that the line connecting the center of gravity of the transport container and the outer corner of the bottom of the outer cylinder makes with the center line of the transport container. A radioactive material transport container comprising a portion extending radially outward of the container.