JPH0240560Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention stores a cask in a storage container with its upper part exposed, and arranges a sheet-like material between the upper part of the cask and the storage container. The present invention relates to a sealing structure between the lower end of the sheet-like object and the storage container in a cask sealing device that seals the upper end of the sheet-like object and the cask, and also seals the lower end of the sheet-like object and the storage container.

Spent nuclear fuel is stored in a cask (spent nuclear fuel transport container) and immersed in a fuel pool from the viewpoint of preventing exposure to radiation and cooling. In this case, if the cask is directly immersed, the outer surface of the cask will be contaminated by the already contaminated pool water.To avoid this, for example, the cask may be stored in a storage container with the top exposed. The space between the upper part and the storage container is sealed with a sheet-like material, in particular, the lower end of the sheet-like material is covered with the storage container and secured from the outside with a tightening band, and the inside of the sheet-like material and the storage container is sealed. However, in such a case, the tightening band may come off, or even if it is not so, the sheet-like material and the storage container may become separated due to subtle irregularities on the outer surface of the storage container. There are problems such as difficulty in completely sealing with the

The present invention solves the above-mentioned problems and provides a seal structure in a cask seal device that can reliably ensure a seal between the lower end of a sheet-like object and a storage container.

That is, the seal structure of the cask seal device of the present invention includes an O-ring and an O-ring deformation prevention ring having a narrower cross-sectional width on the inner surface of the lower end of the sheet-like material, and the O-ring deformation prevention ring is attached downwardly to the O-ring. The sheet-like object is secured to the storage container from the outside of the O-ring with a tightening band at a position where both the O-ring and the O-ring deformation prevention ring can be pressed. , characterized in that the O-ring seals between the lower end of the sheet-like material and the storage container.

An embodiment of the seal structure of the cask seal device of the present invention shown in the drawings will be described below.

In Fig. 1, numeral 1 denotes a cask, inside which spent nuclear fuel can be stored, and fins 10, 10, . There is. 11
1 is a trunnion for suspending the cask 1, and 12 is a lid of the cask 1. Reference numeral 2 denotes a stainless steel storage container in which the cask 1 is stored with its upper portion exposed as shown in the figure. Reference numeral 3 denotes a sheet-like material which is disposed between the upper part of the cask and the storage container, and whose upper end is sealed to the cask 1 and whose lower end is sealed to the storage container 2. The sheet-like material 3 is
As shown in detail in Fig. 2, the air supply and discharge pipe 3
0, and a cylindrical seal body 32 made of a material such as rubberized cloth and extending integrally around the periphery of the rubber tube part 31. The seal body 32 is formed by injecting air from the air supply/discharge pipe 30 to expand the rubber tube portion 31 and sealing it between the fins 10 and 10 at the top of the cask 1 as shown in FIG. The lower end is long enough to reach the outside of the storage container 2, and a water supply/discharge pipe 33 and an exhaust port (not shown) are provided on the side surface thereof.

In the present invention, as shown in FIG. 2, an O-ring 4 and an O-ring deformation prevention ring 5 having a narrower cross-sectional width are provided on the inner surface of the lower end of the sheet-like material 3 to prevent deformation of the O-ring. Remove the prevention ring 5 from the corresponding 0
The sheet material 3 is fixed to the storage container 2 by contacting the ring 4 from below, and the sheet-like material 3 is secured to the storage container 2 from above and outside the O-ring 4 with a tightening band 6. At this time, if the sheet-like object 3 is secured only with the tightening band 6 without securing the O-ring 4 and the O-ring deformation prevention ring 5 as described above, the sealed sheet-like object 3 and the storage container 2 When filling the inside of ^the sheet by press-fitting water, water leakage occurs at around 0.5Kg/ ^cm2 . It is not possible to secure a seal in the area. In the present invention, in order to ensure this seal, the O-ring 4 is fixed as described above, and if only O-phosphorus is used, the O-ring 4 will rotate and twist as the sheet-like material 3 expands due to filling with pressurized water, resulting in a seal. Since the effect is weakened, the O-ring deformation prevention ring 5 is brought into contact with the O-ring 4 as described above to prevent the O-ring 4 from twisting and to ensure the sealing effect of the O-ring 4. Therefore, the cross-sectional shape of the O-ring deformation prevention ring 5 is rectangular in the embodiment, but it can be any shape that can prevent the O-ring 4 from twisting. Also, the cross-sectional width of the O-ring deformation prevention ring 5 needs to be smaller than the cross-sectional width of the O-ring 4. If the cross-sectional width of the O-ring deformation prevention ring 5 is larger than the cross-sectional width of the O-ring 4, the O-ring deformation prevention ring 5 is The O-ring 4 contacts the storage container 2 when sealing the lower end of the storage container 2.
Since the O-ring 4 does not come into contact with the O-ring 4, the sealing effect of the O-ring 4 cannot be improved. The securing position of the tightening band 6 is preferably the position shown in the embodiment (the position shown in FIG. 2). Any position is sufficient as long as it can be brought into close contact with the storage container and can press both the O-ring and the O-ring deformation prevention ring. In this invention,
When lashing with the tightening band, the O-ring deformation prevention ring prevents the O-ring from twisting and excessive deformation, so if the lashing position of the tightening band is the above position, the lower end of the sheet-like object The O-ring securely seals between the storage container and the storage container.

Next, to explain the sealing operation of the cask 1, first, spent nuclear fuel is stored in the cask 1, and the cask 1 is suspended via its trunnion 11 and stored in the storage container 2, and before or after this storage. At this time, the sheet-like material 3 is surrounded on the outside of the cask 1, and the rubber tube portion 31 at the upper end of the sheet-like material 3 is attached.
the adjacent fins 10, 10 at the top of the cask 1.
By injecting air through the air supply/discharge pipe 30 into the rubber tube part 31 disposed between them, the rubber tube part 31 is expanded to seal the upper end of the sheet-like material 3 and the upper part of the cask 1, and then, With the lower end of the sheet-like material 3 surrounding the upper part of the storage container 2, the lower end of the sheet-like material 3 is secured to the storage container 2 by a tightening band 6 from above and outside the O-ring 4. After sealing the upper and lower ends of the sheet-like material 3 in this manner, water is pressed into the sheet-like material 3 and the storage container 2 through the water supply/drainage pipe 33 to fill them. At this time, if the seal is incomplete, water will leak from the incomplete portion, so after confirming that there is no water leakage, the cask 1 and the storage container 2 are immersed in the fuel pool.

As described above, according to the seal structure of the cask seal device of the present invention, an O-ring and an O-ring deformation prevention ring with a narrower cross-sectional width are provided on the inner surface of the lower end of the sheet-like object. The sheet-shaped object is brought into contact with and fixed to the O-ring from below, and is attached to the storage container using a tightening band at a position where both the O-ring and the O-ring deformation prevention ring can be pressed from the outside of the O-ring. Since the O-ring seals between the lower end of the sheet-like material and the storage container, the O-ring deformation prevention ring
The sealing effect of the ring can be ensured, and the sealing effect can be achieved at the lower end of the sheet-like article.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the main parts thereof. 1... Cask, 2... Storage container, 3... Sheet-like object, 4... 0 ring, 5... 0 ring deformation prevention ring, 6... Tightening band.

Claims (1)

[Claims for Utility Model Registration] (1) A cask is stored in a storage container with its upper part exposed, and a sheet-like material is arranged between the upper part of the cask and the storage container, and the sheet-like material is A sealing structure between the lower end of the sheet-like object and the storage container in a cask sealing device that seals the upper end of the sheet-like object and the cask, and also seals the lower end of the sheet-like object and the storage container, comprising: An O-ring and an O-ring deformation prevention ring with a narrower cross-sectional width are attached to the inner surface of the lower end of the sheet-like object, and the O-ring deformation prevention ring is attached to the O-ring deformation prevention ring.
The sheet is brought into contact with and fixed to the ring from below, and the sheet is attached to the storage container from the outside of the O-ring using a tightening band at a position where both the O-ring and the O-ring deformation prevention ring can be pressed. A seal structure in a cask seal device, characterized in that the seal is secured between the lower end of the sheet-like material and the storage container using the O-ring. (2) The seat structure in the cask seal device according to claim (1) of the utility model registration, wherein the O-ring deformation prevention ring has a rectangular cross section.