JPH0672951B2 - How to replace the lip seal in a storage container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a storage container for storing and transporting a large amount of radioactive substances, toxic substances to the human body, etc. The present invention relates to a method of replacing a lip seal attached between a lid and a container lid.

<Prior Art> As such a storage container, for example, one having a ring member screwed around a top opening of a bottomed container body made of stainless steel with a bolt is generally used. There is. A sealing material called a lip seal made of a silicon-based organic material (for example, silicon rubber) or soft vinyl chloride resin is fitted in the groove formed on the inner peripheral edge of the ring member.

The opening of this storage container is closed by a container lid.
That is, in order to attach the container lid to the opening of the storage container, usually, a plurality of inner protruding protrusions provided on the inner periphery of the ring member and a plurality of outer protruding protrusions provided on the outer periphery of the container lid are relatively disposed. It is carried out by rotating and fitting in the circumferential direction, and by the rotation in the opposite direction, both are separated.
The airtightness between both members is maintained by the lip seal provided between them.

The radioactive substances such as plutonium and uranium mixed oxides and the toxic substances to the human body are usually placed in and out of this storage container with the opening of this storage container joined to the opening of the glove box isolated from the external environment. Be seen.

That is, a flange is provided on the periphery of the opening (usually closed by a cover) for fitting the storage container formed in the base plate of the glove box. Then, the inner peripheral surface of the flange and the outer peripheral surface of the ring member at the opening of the storage container are engaged with each other by a fitting structure similar to the above which can be engaged and disengaged by rotating in the circumferential direction, and the both are joined.

In this joined state, the container lid is in a state of being overlapped with the cover that closes the opening of the glove box, and in this state, both are removed together in the glove box. Next, the radioactive substance or the like provided in the glove box is stored in the storage container, and thereafter, the storage container is detached from the glove box in a state where the storage container is sealed by the container lid by a means reverse to the above.

<Problems to be Solved by the Invention> By the way, the above-mentioned lip seal gradually deteriorates due to rotational sliding in the circumferential direction when the container lid is attached and detached to cause pain, or a substance to be put into and taken out of the container is In the case of a fine powder nuclear fuel material, there is a problem that the fine powder adheres to the lip seal and is difficult to remove.

Therefore, when the storage container is used for a long period of time, it is necessary to replace them. Further, when the container lid, the O-ring, etc. provided at the opening of the storage container are contaminated or damaged, the replacement of them is also required.

In the replacement work of this lip seal, etc., it is required to reliably control the contamination of nuclear materials, but when the internal volume of the storage container is large, the entire inner surface of the storage container including the lip seal is contaminated. It is extremely difficult to replace the lip seal etc. safely and with good workability without exposing the part, and at present, no effective replacement method has been developed, and the entire storage container should be discarded or stored for a long time. Has become.

The present invention provides a lip seal that can replace a lip seal or the like attached to the inner circumference of an opening of a storage container safely and with good workability without releasing a contaminated portion on the inner surface of the storage container for radioactive substances, toxic substances, and the like. It is intended to provide a method of replacing a seal.

<Means for Solving the Problems> A method for replacing a lip seal according to the present invention is a storage container for storing and transporting a large amount of radioactive substances, toxic substances to the human body, etc. that cannot be handled in an open state. A method for replacing a lip seal attached between an inner peripheral edge of a ring member fixed around the top opening of the container and a container lid, wherein the opening of the storage container is joined to the opening of the first glove box. In this state, first, the container lid is removed, and an upper temporary lid fitted to the ring member, which is provided in the first glove box, and is separable from the upper temporary lid and positioned in the opening. The first step of closing the opening with a temporary lid member with a seal having a lower temporary lid, and the storage after the first step is completed in the opening of the second glove box. Joining the opening of the container, and in a state where the opening end of the storage container is closed by a seal member provided on the outer periphery of the lower temporary lid, the upper temporary lid is separated from the lower temporary lid together with the ring member, Then, after replacing the lip seal attached to this ring member, a second step of joining the upper temporary lid together with the ring member to the lower temporary lid and the second step in the opening of the first glove box are performed. In a state where the opening of the finished storage container is joined, first, the temporary lid member with a seal is removed from the opening, and then the third step of sealing the opening with the container lid is included. Use as a summary.

Further, in the second step, consumables such as an O-ring attached to the ring member may be replaced with the replacement of the lip seal, and the upper temporary lid and the ring member may be decontaminated. You can

<Operation> As described above, the temporary lid member with a seal is attached to the opening of the storage container in the first glove box, and storage is performed by the seal member provided on the outer periphery of the lower temporary lid constituting the temporary lid member with a seal. If the ring member is cut off together with the upper temporary lid for replacing the lip seal in the second glove box with the opening of the container closed, contamination in the second glove box at the time of this separation will occur. It is possible to prevent the level from rising.

Therefore, the second glove box can be managed at a very low contamination density, and therefore the measures for preventing contamination in the glove box can be simplified, and the work efficiency required for replacing the lip seal and the like can be improved.

Further, since the contamination of ring members other than the consumable items removed in the second glove box can be completely decontaminated by a decontamination device or the like, for example, it is possible to decontaminate even the contamination that cannot be removed by the normal wipe decontamination, Therefore, if decontaminating, it is possible to reuse those that can be used.

And since the lip seals (lip seals, ring members, O-rings, etc.) can be replaced safely and reliably in this way, the storage container can be maintained, and thus the storage container can be used for a long period of time. Economic efficiency can be improved.

<Examples> Examples will be described below.

In FIG. 1 (A), the storage container 1, which cannot be used due to contamination of the lip seal or the like, is first attached to the opening provided in the first glove box 2 as indicated by arrow A. That is, with the container lid 4 of the storage container 1 fitted to the facility opening cover (cell door) 3 that is a cover attached to the opening of the first glove box 2, the storage container 2 is rotated,
These lids are brought into a state in which they are closely attached and connected by the fitting structure.

Next, the facility opening lid 3 and the container lid 4 were connected and fixed to the top opening of the storage container 1 together with a bolt or the like by a lid handling machine (not shown) provided inside the first glove box 2. The ring member 5 is separated and these are pulled out to the inside of the first glove box 2 as shown by arrow B.

After that, a temporary lid member 6 with a seal is attached to the inside of the opening of the storage container 1 as shown by an arrow C to prevent the spread of contamination from the inside of the storage container.

As shown in FIG. 2, the temporary seal cover member 6 includes an upper temporary cover 61, a lower temporary cover 62, and a low cover 63. Of these, the upper temporary lid 61 is the inner projection 5a formed on the inner peripheral surface of the ring member 5.
And the outer projection 61a connected by the above-mentioned fitting structure. Therefore, by rotating the ring member 5 and the upper temporary lid 61 relatively in the circumferential direction, as shown in FIG. Fit together. An annular seal member 61b is provided in the recess formed on the outer periphery of the bottom of the upper temporary lid 61. The seal member 61b is pressed against the inner peripheral surface of the ring member 5.

Further, the lower temporary lid 62 is connected to the upper temporary lid 61 by a bolt (fixing screw 65) provided on the upper surface of the upper temporary lid 61. An annular seal member 62a, which is in pressure contact with the seal member 61b, is provided in the recess formed on the outer periphery of the upper surface of the lower temporary lid 62. Further, the end portion of the opening portion located below the ring member 5 of the storage container 1 is gradually tapered in the opening direction, and the outer peripheral surface of the seal member 62a is pressed against the inner peripheral surface of the opening portion.

The sealing members 61b and 62a described above are respectively brought to the joint between the ring member 5 and the opening of the storage container 1 by a tightening screw (not shown), and the inner peripheral surface of the ring member 5 is Alternatively, the inner peripheral surface of the opening of the storage container 1 and the inner peripheral surface of the opening are preliminarily adjusted so as to be in pressure contact with each other with a proper tightening force, that is, with a force that does not allow fine powder such as radioactive material to go outside.

Further, a seal member 62b whose outer peripheral portion is bent downward is located below the seal member 62a, and is formed on the outer periphery of the low lid 63 located below the lower temporary lid 62. The sealing member 62b is pressed upward in the drawing by the tip of the annular projection 63a to expand its diameter in the circumferential direction, and is pressed against the inner peripheral surface of the opening and closes the inner peripheral surface. Incidentally, the above-mentioned seal member 61
Similar to the lip seal 8, b, 62a, 62b, etc. are made of silicone rubber, soft vinyl chloride resin, or the like.

Further, through holes 61c, 62c, 63c which are coaxially communicated with each other are formed in the central portions of the upper temporary lid 61, the lower temporary lid 62 and the bottom lid 63, respectively. A disk-shaped head 64a, which is located in the through hole 61c and is held on the outer upper surface of the through hole 62c, and a screw groove formed in the inner peripheral surface of the through hole 3c are screwed into these through holes. A fastening member 64 including a screw portion 64c and a connecting portion 64b between the head portion 64a and the screw portion 64c is provided. By rotating this fastening member 64 in the direction of arrow I in FIG. 2, the bottom cover 63 moves in the direction of arrow II, and the annular projection 63a of the bottom cover 63 causes the sealing member 62b to expand in the circumferential direction. Diameter.

In addition, the tip of the upper temporary cover 61 is attached to the lower temporary cover 62.
A plurality of (for example, three) fixing screws 65 for partitioning the inner surface, which are screwed into the upper surface of the upper temporary cover, are provided at substantially equal intervals.
When the fixing screw 61 is fitted to the ring member 5,
When 65 is tightened, the lower temporary lid 62 moves to the bottom lid 63 side.

Then, if the temporary lid member with seal 6 is attached to the ring member 5 to close and fix the opening of the storage container 1 in this way,
The storage container 1 is rotated in the opposite direction to the first glove box 2 to separate the storage container 1 from the first glove box 2 together with the temporary lid member with a seal 6 as shown by an arrow D.

As described above, the storage container 1 that has undergone the steps in the first glove box 2 is placed in the second glove box 7 having an opening having an inner diameter equal to or larger than the outer diameter of the ring member 5 as described above. Connect with the same fitting structure as. In the figure, 9 is an O-ring that is pressed between the extension of the outer periphery of the opening of the storage container 1 and the opening of the second glove box 7.

Then, in the second glove box 7, the bolts for connecting the upper temporary lid 61 and the lower temporary lid 62 and the connecting bolts for connecting the ring member 5 and the storage container opening are removed, respectively. The ring member 5 is integrally separated from the opening of the storage container as shown by the arrow F, and separated from the storage container 1.

Here, when the upper temporary lid 61 is separated from the lower temporary lid 62, the sealing material 62b on the lower side of the lower temporary lid 62 acts as a stopper, so that the lower temporary lid 62 and the bottom lid 63 move to the opening side. Therefore, the opening of the storage container 1 is kept in a completely closed state, and the contamination between the sealing members 62a and 63a does not fly into the second glove box. Further, the contamination attached to the inner peripheral surface of the ring member 5 is contained between the lip seal 8 and the sealing material 61b, and the contamination does not scatter in the second glove box. From the above, the second glove box 7
It is possible to completely prevent the spread of pollution in.

The upper temporary lid 61 removed from the storage container 1 in this way,
The ring member 5, the lip seal 8, and the O-ring attached to the ring member 5 and the like are checked through the holes provided in the second glove box 7 after confirming the presence or absence of contamination on the seal surface. It is transferred to the decontamination glove box 10 shown in FIG. The lip seal 8 that cannot be decontaminated is discarded at this point.

In the decontamination glove box 7, the upper temporary lid 61, the ring member 5, and the ring member 5 are decontaminated by washing or the like in the decontamination devices 11 to 13 inside as shown by arrows H to J. In addition, those that cannot be decontaminated and those that cannot be reused are discarded and replaced with new ones, for example, in the route of arrow K.

The upper temporary lid 61, the ring member 5, the O-ring, etc., which have been decontaminated or replaced in this way, are transferred from the decontamination glove box 10 as shown by an arrow L after checking the presence or absence of contamination, and a new lip is added. After being assembled with the seal 14 as shown by the arrow M, it is again transferred into the second glove box 7 as shown by the arrow N.

Then, in the second glove box 7, first, the ring member 5, the lip seal 14, the upper temporary lid 61 and the like are attached to the opening of the storage container 1 by bolts or the like as shown by an arrow O. After that, the fixing screw 65 is loosened, and the fastening member 64 is rotated in the direction opposite to the arrow I in FIG.

The storage container 1 whose lip seal has been replaced as described above is reconnected to the first glove box 7 through the paths indicated by arrows P and Q. In the first glove box 2,
First, from the opening of the storage container 1, the temporary lid member 6 with a seal is indicated by an arrow R.
And then reattach the facility opening lid 3 and the container lid 5 to the opening of the storage container 1 as shown by the arrow S, and then remove the storage container 1 together with the container lid 5 from the first glove box 2, A series of work is completed.

The storage container whose lip seal has been replaced in this way is returned to the process and reused.

<Effects of the Invention> As described above, according to the replacement method of the present invention, it is possible to prevent an increase in the contamination level when the ring member or the like is separated for replacement of the lip seal in the second glove box. Therefore, the second glove box can be managed at a very low contamination density, and the measure for preventing contamination in this glove box is simplified, and therefore the work efficiency required for replacement of the lip seal and the like can be improved.

In this way, since the lip seal can be replaced safely or reliably and other related parts can be replaced or decontaminated, and the storage container can be maintained, the storage container can be used for a long period of time and the economy is improved. There is an effect such as being able to.

[Brief description of drawings]

1 (A) and 1 (B) are explanatory views of each step in the embodiment, and FIG. 2 is an explanatory view showing a state in which the opening of the storage container is closed by a temporary lid member with a seal. 1 ... storage container, 2 ... first glove box, 4 ...
… Container lid, 5 …… Ring member, 6 …… Seal temporary lid material,
7 …… Second glove box, 8,14 …… Lip seal, 61 …… Upper temporary lid, 62 …… Lower temporary lid, 63 …… Bottom lid.

Claims (3)

[Claims] 1. A storage container for storing and transporting a large amount of radioactive substances, toxic substances to the human body, etc., which cannot be handled in an open state, and an inner peripheral edge of a ring member fixed around the top opening of the storage container. A method of exchanging a lip seal attached to a container lid, wherein the container lid is first removed in a state where the opening of the storage container is joined to the opening of the first glove box, and the first lid A temporary lid member with a seal, which is provided in the glove box and has an upper temporary lid fitted to the ring member and a lower temporary lid that is separable from the upper temporary lid and is located in the opening, The first step of closing the opening is joined to the opening of the second glove box, and the opening of the storage container that has finished the first step is joined to the opening. With the opening end of the storage container closed by a member, the upper temporary lid is separated from the lower temporary lid together with the ring member, and then the lip seal attached to the ring member is replaced, and then the upper temporary lid is ringed. A second step of joining the lower temporary lid together with the member, and an opening of the storage container that has finished the second step joined to the opening of the first glove box, first from this opening. A method of replacing a lip seal in a storage container, comprising a third step of removing the temporary lid member with a seal and then sealing the opening with the container lid. 2. The replacement method according to claim 1, wherein in the second step, a consumable item such as an O-ring attached to the ring member is replaced. 3. The replacement method according to claim 1, wherein in the second step, the ring member, the upper temporary lid and the like are decontaminated.