JPS6336318Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a basket structure for disposing of spent nuclear fuel fragments, and in particular, the basket includes a first basket that directly stores the shredded fragments, and a second basket that covers the basket and stores the spent nuclear fuel fragments so as to be freely accessible. The first basket has a double structure consisting of a second basket and a second basket.
A locking part is formed to prevent the first basket from being pulled out from one side of the basket, and when cleaning the sheared pieces, the first basket is pulled out from the second basket and is locked to dissolve the first basket. The present invention relates to a spent nuclear fuel fragment disposal basket structure which is immersed in a liquid and allows a first basket to be pulled out from the other side of a second basket and transported independently.

In the process of reprocessing spent nuclear fuel, there are processing steps such as dismantling, cutting, decoating, and melting the spent nuclear fuel. If decoating is not easy, the cut pieces are stored in a melting tank. The fuel is dissolved while being washed with a dissolving solution, and the washed fragments are taken out of the dissolution tank and disposed of as waste.

As shown in Figure 1, spent nuclear fuel from a nuclear power plant is cooled and stored in storage pool 1.
It is sheared into small pieces by a shearing machine 3 in a cutting machine room 2. This sheared piece is passed through a distributor 4 to a pipe 5.
and is sent into the basket 7 in the dissolution tank 6. A dissolving solution such as nitric acid is circulated and supplied to the dissolving tank 6 from a liquid storage section 8 . The sheared fragments washed in the dissolution tank 6 are taken out together with the basket 7, disposed of in a waste container 9, and then transferred.

In the above process, the sheared pieces are directly loaded into the dissolution tank 6 by gravity through the pipe 5, so that the sheared pieces in the form of powder or granules are scattered, causing problems such as contamination and off-gas treatment. Furthermore, since the sheared fragments are fed through the pipe 5 by gravity, they are
An error occurs in the amount of sheared pieces processed at each time.
It was not possible to quantify the amount, which caused a problem that the cleaning process was insufficient.

On the other hand, as shown in FIG. 2, the cutting machine room 10, melting chamber 11, waste treatment chamber 12, etc. are divided into cells, and they are communicated through a through hole 13, and the entrance and exit of the through hole 13 is connected to a shielding door 14. In order to reduce the prevention of contamination inside the cell, the cut pieces are stored in a basket 15 in the cutting machine room 10, and transported through the through hole 13 into the melting chamber 11 and into the melting tank 16.
After washing, the basket 15 containing the shredded pieces is carried to the waste treatment room 12 and transferred. However, with this method,
The through hole 13 is formed in the shape of a small hole to ensure complete shielding, and therefore the basket 15 is required to be small enough to pass through the through hole 13. On the other hand, as shown in FIG. 3, the dissolution tank 16 is formed deep and long in the direction of insertion of the basket due to restrictions such as the arrangement of the dissolution liquid discharge pipe, and the dissolution liquid 19 is stored at the bottom of the tank. However, a problem has arisen in that it is difficult to insert this into the storage portion of the solution 19 from the open mouth of the solution tank 16 by remote control using a hanger or the like.

This invention was devised to solve the above problems, and its purpose is to store the shredded pieces in a small basket to prevent contamination and quantify the throughput, as well as to store the shredded pieces in a small basket. It is an object of the present invention to provide a spent nuclear fuel fragments processing basket structure which allows the basket to be easily inserted into and removed from a melting tank by remote control and which can also be used as a container for transporting fragments.

As shown in FIG. 4, the basket 20 is composed of a small first basket 21 for storing the sheared pieces, and a second basket 22 that covers the basket 21 and stores it in a manner that allows it to be moved in and out. As shown in FIG. 5, the first basket 21 is formed of a cylindrical body whose upper side is open and whose lower side is closed, and is made of a material such as stainless steel (SUS304L). A large number of holes 33 are formed through the outer peripheral wall of the cylinder. A flange-like locking portion A23 is formed on the upper outer periphery, and the open port 24 is formed to have a smaller diameter than the inner diameter of the cylinder, and as shown in FIG. A slit 25 is formed in the diametrical direction of the opening 24 through which a longer bar can pass.

The second basket 22 is as shown in FIG.
It is formed of a cylindrical body made of stainless steel (SUS304L) with open upper and lower sides, and the opening on the lower side has a size that allows the outer circumference of the first basket 21 to enter and exit. A stepped locking portion C26 is formed to which the locking portion A23 of the first basket 21 locks. Therefore, the first basket 21 cannot be pulled out from the lower side of the second basket 22 due to the engagement between the locking part A23 and the locking part C26. The opening on the upper side of the second basket 22 has a size that allows the first basket 21 to pass therethrough, and a conical portion 28 is formed on the outer periphery of the upper side. Furthermore, a locking member 29 is provided on the upper side edge of the second basket 22 to which a hanger or the like is locked.

Next, as shown in FIG. 8, a partition plate 31 having a conical hole 30 formed in the center thereof is provided on the upper inner periphery of the dissolution tank 16. The conical portion 28 of the second basket 22 is engaged with the conical hole 30, and the second basket 22 is locked.
The second basket 22 is arranged at the center of the dissolution tank 16. Note that, as described above, the dissolving liquid 19 is stored on the lower side of the dissolving tank 16.

Next, the operation of this embodiment will be explained.

As explained with reference to FIG. 2, the sheared pieces in the cutting machine room 10 are stored in the first basket 21. Since the first basket 21 is small as described above, it can easily pass through the through hole 13. Inside the melting chamber 11, there is a hanging tool 3 as shown in FIG.
5 is provided, and a rod 36 is provided at the tip of the hanging tool 35. The length of this rod 36 is shorter than the cylindrical inner diameter of the first basket 21 and longer than the inner diameter of the opening 24, and when it rotates through the slot 25 shown in FIG. Lock on the upper side. The above operation of the hanging tool 35 is easily performed, and the first basket 21 is easily stored in the second basket 22 provided on the floor surface 37 of the melting chamber 11, as shown in FIG. Next, as shown in FIG. 11, another hanging device 38 is used to
Locking the locking member 29 of the second basket 22,
Lift up the second basket 22. in this case,
Since the locking portion A23 and the locking portion C26 engage with each other as described above, the first basket 21 is suspended from the second basket 22 together. Then, in this state, it is inserted into the dissolution tank 16 as shown in FIG. The first basket 21 is connected to the second basket 22 as described above.
Since the dissolution tank 16 is suspended from the bottom, even if the solution 19 in the dissolution tank 16 is at the bottom, it can be completely immersed. Then, the first basket 21 is placed in the dissolving tank 1.
Since there is no need to directly insert the device into the device 6 using a hanging device, remote control for insertion is extremely easy.

After washing the sheared pieces as described above,
The second basket 22 is lifted up and returned to the state shown in FIG. 10 again. Here, in the same way as shown in FIG. 9, only the first basket 21 can be taken out using the hanger 35, passed through the through hole 13, and transferred to the waste treatment chamber 12.

As is clear from the above explanation, the present invention provides the following excellent effects.

(1) A basket containing shredded fragments can be easily inserted into and removed from the dissolution tank by remote control.

(2) The basket containing the sheared pieces can be made smaller and can easily pass through small through holes.

(3) Only the basket containing the shredded pieces can be transported, and this can also be used as a transport container.

(4) Since the sheared fragments are stored in a regular shaped basket, they can be quantified and cleaned completely.

(5) Since sheared fragments are not transported by gravity, etc., contamination can be prevented.

(6) The structure is simple and the handling is reliable and easy.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram that outlines the conventional treatment process for spent nuclear fuel fragments, Figure 2 is an explanatory diagram that also explains the treatment process, and Figure 3 is a vertical cross-sectional view that outlines the melting tank. Fig. 4 is a longitudinal sectional view showing the configuration of a basket according to an embodiment of the present invention, Fig. 5 is a longitudinal sectional view of the first basket, Fig. 6 is a top view of the basket as viewed from arrow A, and Fig. 7 is a longitudinal sectional view of the first basket. Partial longitudinal sectional view of the basket,
Fig. 8 is a vertical cross-sectional view showing the basket inserted into the melting tank, Fig. 9 is an explanatory view showing the hanging tool engaged with the first basket, and Fig. 10 is the first basket inserted into the second basket. FIG. 11 is an explanatory view showing a state in which the hanging tool is engaged with the second basket. In the figure, 10 is a cutting machine room, 11 is a dissolution chamber, 12 is a waste treatment chamber, 16 is a dissolution tank, 19 is a dissolution liquid, 2
0 is the basket, 21 is the first basket, 22
23 is a second basket, 23 is a locking part A, 24 is an opening, 25 is a slot, 26 is a locking part C, 28 is a conical part, 29 is a locking member, and 35 and 38 are hanging tools. .

Claims (1)

[Scope of utility model registration request] Spent nuclear fuel sheared fragments that have come out of the nuclear power plant and have been sheared into small pieces are stored, transferred to a dissolution tank where the sheared fragments are cleaned, and after the sheared fragments are soaked and cleaned, the cleaned cut pieces are In the basket where the pieces are stored and discarded in the waste container, there is a first basket with a number of holes formed through it to directly store the shredded pieces and cause the shredded pieces to come into contact with and dissolve the dissolving solution in the dissolution tank. It is composed of a basket and a second basket that covers the first basket and stores it in a manner that allows it to be taken in and out, and the first basket has a locking part on the upper open side to which the hanging tool is locked. ,
The second basket has, on its upper outer periphery,
A conical portion is formed to position the second basket in the center of the melting tank, and a locking member to which a hanging tool is locked is formed above the second basket; A locking portion is formed at the engaging portion between the upper outer peripheral portion of the second basket and the lower inner peripheral portion of the second basket to prevent the first basket from being pulled out when the first basket is pulled out. A basket structure for processing spent nuclear fuel fragments.