JPS6221096A - Melter for previously irradiated nuclear fuel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for melting irradiated nuclear fuel, in particular spent nuclear fuel.

[Conventional technology]

FIG. 10 shows the structure of a conventionally proposed nuclear fuel melting tank.

In the figure, with the melting tube flange 05 open,
into the melting cylinder 01. Next, open the guide pipe lid 07, put the fuel sheared piece 03 into the Basquera 1-02 through the fuel sheared piece guide pipe 06, and then close the melting cylinder lid 05 and the guide pipe. Close the lid 07. Next, heating jacket) 015
Steam is passed inside to heat the melting cylinder 01. This is good.

As the temperature of the solution increases, the dissolution reaction starts and the solution begins to flow in the direction of the arrow. When the concentration of the solution (HNO3) decreases due to the dissolution reaction, a new solution is added into the storage tank 08 from the solution inlet pipe 09. The reaction gas generated by the dissolution reaction and the water vapor generated when the solution is heated flow in the direction of the dashed arrow.

The reaction gas is discharged from the yarn through the outlet pipe 010.

Once the dissolution is complete, the pulp is opened and the dissolved solution is sent to the next process. Next, the pulp is closed, and a new dissolving solution is put into the dissolving solution inlet pipe 09 into the dissolving tank 08 and the dissolving cylinder 01, and the dissolving solution is poured into the dissolving solution inlet pipe 09 into the dissolving tank 08 and the dissolving cylinder 01. Melting cylinder 01° basket 02 and fuel shear piece 0
Wash 3. After cleaning is completed, open the melting cylinder lid 05 and put the Paskera) 02 and fuel shear pieces 03 into the melting cylinder 0.
1 and put a new basket 02 into the melting cylinder 01. Hereinafter, the above-described throughput process is repeated, and the melting operation of the fuel sheared pieces 03 is performed again.

[Problem that the invention seeks to solve]

In conventional dissolution tanks, each process, such as the loading process of the basket and fuel sheared pieces, the dissolution reaction process, the dissolving liquid removal process, the cleaning process, and the discharging process of the basket and fuel sheared pieces, takes a batch system that is independent of each other. ing. Therefore, while a certain process is being performed, other tasks cannot be performed.

In addition, in conventional melting tanks, the basket remains immersed in the melting liquid during the melting process, so the liquid inside and outside the basket cannot be exchanged quickly. It was difficult to make contact with others.

[Failure to solve the problem]

The present invention has been made to solve the above-mentioned problems. In the irradiated nuclear fuel melting device of the present invention,
A basket member into which the nuclear fuel fragments to be melted are placed is set within a plurality of holding members of a rotary conveyance device that rotates around the central axis of the melting device and is driven in the vertical direction. The solution storage section of the dissolution tank main body in which the holding member is immersed is formed in an annular shape, and the inside thereof is divided into a dissolution section and a washing section. A basket member exchange device is installed upright on the top of the melting tank body, spanning the melting section and the cleaning section. A new basket member is carried in by this exchange device.

It is inserted into the holding member of the rotary conveyance device, and as it rises, rotates, and descends, it is pulled up from the solution, moved above the solution, and
Repeat immersion into the solution.

Finally, it reaches the cleaning section where it is cleaned.

The basket member that has gone around the inside of the dissolution tank is pulled up and carried out together with the dissolution residue therein by the exchange device.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of the entire apparatus, showing the dissolution tank main body 10 and the basket exchanger 20.

To explain about FIG. 2, which is an elevational sectional view taken along the line ■-■ in FIG. 1, and FIG. 3, which is a planar sectional view taken along the If-N line in FIG. 2, and FIG. , the cleaning section 1a and the dissolving section 1b are composed of a cleaning section 1a, a dissolving section 1b, and a gas phase section IC.

Arranged in a ring. The solution enters the cleaning part 1a through the cleaning liquid inlet pipe 12, and then passes through the communication pipe 21 to the dissolving part 1b.
Finally, it exits from the dissolution tank main body 10 through the dissolution liquid outlet pipe 22. The gas phase part IC includes a cleaning part 1a and a dissolving part 1b.
It is formed in the upper part of the tank body 10 and communicates with the reaction gas outlet 10d of the lid 10C of the tank body 10. The upper part of the tank body 10 is formed as a cylindrical container, and the lower melting part tb is formed in an annular shape.
A fuel shear piece supply chute 2 is provided in the vicinity of the starting point of the fuel shearing piece supply chute 2, which communicates with the gas phase section IC.

Further, a nine-rotation conveyance device 40 is provided in the center of the gas phase section tc. Eight tower arms 42 are provided at equal intervals on the upper part of the tower 41. A holding member, that is, a basket hanging device 43 is suspended from the tower arm 42, and therein are baskets 6a, 6b+5c,
6d+ 5e, 5r, 6g.

6h is stored. A nine-rotation drive device 44 and a vertical drive device 45 are installed at the bottom of the tower 41, and when these devices 44 and 45 are driven, the tower 41 performs rotation and vertical movement within the gas phase IC. . Therefore, the hanging tool 43
The inner pass scalers 63 to 6h are immersed in the dissolving solution and the cleaning solution, and sequentially move through the dissolving section 1b and the cleaning section 1a. Note that the tower 41 rotates clockwise in steps at 1/8 revolutions in the raised position.

FIG. 4 is a developed sectional view taken along the center circumferential line of the annular portion of the tank body 10 in FIG. 3.

Tower 41 is in a raised position.

A basket exchange device 20 is provided at the top of the dissolution tank main body 10. Inside the exchange room 16, an elevating and lowering exchange device 19 is installed.

The lifting exchange device 19 includes two hanging shafts 19a,
19b, two cars alternately pass scale) 68~6h
Take in and out.

Passquera) 68 to 6h have a plurality of small holes through which the liquid inside and outside the basket flows in and out. Moreover, on the upper part of the baskets 6a to 6h.

A protrusion 60h for hanging the hook 19ah is provided at the tip of each of the hanging shirts 19a and 19b (see FIG. 5). To replace the Basquera 68 to 6h, for example, insert the hook 19ah into the Basquera 6h, rotate it, hook the hook 19ah to the protrusion 60h of the basket 6h, hang the Basquera 6h, and perform the replacement work.

In FIG. 4, a partition wall 15 between the dissolving section 1b and the cleaning section 1a is shown.
In each case, connecting pipes 21 are opened, and lysate drain pipes 24. each containing pulp. A cleaning liquid drain pipe 23 is provided at the bottom.

Particularly, referring to FIG. 2, at the upper end of the lifting shaft 46 of the vertical drive device 45, there is a frame 47 that supports the nine-rotation drive device 44.
is constructed, and the tower 4I is rotatable between the uppermost position and the lowermost position.

In the fuel shearing piece supply and basket replacement operations in FIGS. 2 to 4, first, the vertical drive device 45 is activated,
Extend the lifting shaft 46.

Raise the tower 41. As a result, baskets 6a to 6h
are all located above the liquid level (Figure 4 shows this state). In this state, fuel shearing piece 7 Vasquera) 6
The supply to a and the replacement of Basquera) 6h are carried out in parallel.

After raising the fuel shearing piece supply tower 41, the fuel shearing piece inlet door 3 is opened, and the fuel shearing piece 7 is transferred from the fuel shearing piece supplying sheet 2 to the basket rack).
6a. Immediately after the supply is completed, close the fuel shearing piece inlet door 3 (FIG. 2 shows the inlet door 3 in an open state).

After raising the basket exchange tower 41, open the door 17' (Figs. 8 and 9) of the basket entrance 17 of the exchange room 16, stretch the hanging shirt 19a of the elevator exchange device 19, and tighten the hook 19ah. Insert the basket 6h into the cleaned basket 1-6h, rotate it once, lift the basket 6h, and move it to the exchange room 16.
(Fig. 2 and Fig. 4 are Pasquera) 6h is shown slightly raised. ). Next, the elevating/lowering exchange device 19 is slid to a standstill, and the hanging shirt 19b from which the empty basket 61 is suspended is moved above the basket entrance/exit 17. Further, as shown in FIGS. 6 and 7, the hanging shaft 19b is extended, the empty basket 61 is set in the basket hanging device 43, and the basket exchanging chamber 16 is placed again.
(lifting shirt inside) Pull back 19b. After this work is completed, the door 17' of the basket entrance/exit 17 is closed.

At this time, the basket exchange room door 18' remains closed and isolated from the outside.

Moving the basket in the dissolution tank After the supply of the sheared pieces 7 and the replacement of the baskets 6h and 61 are completed, the 9-rotation drive device 44 is operated while the tower 41 remains in the ascending state, and the tower 41 is moved l. / Rotate only 8 revolutions. As a result, the baskets 68 to 6g and 6i all move clockwise by 1/8 rotation on the circumference. Therefore, the empty basket 6i comes from the upper position of the washing section 1a to the position of the fuel shear weft entry L0 above the end of the melting section 1b.

Melting and Cleaning of Fuel Shear Pieces After the above-mentioned operations are completed, the vertical drive device 45 is operated to lower the tower 41 as shown in FIGS. 8 and 9.

As a result, Paskera) 68 to 6g and 6i are positioned below the liquid level of the dissolving section 1b and the cleaning section 1a. At this time, a dissolution reaction is carried out in the fuel shearing pieces 7 in the Basquera) 6a to 6e, and a cleaning operation is performed on the fuel shearing pieces 7 in the Basquera) 6f and fg. The reaction gas generated by the dissolution reaction moves in the direction of the dashed arrow and is discharged from the system through the reaction gas outlet 10d.

Carrying the basket out of the system and into the system In FIG. 8, after inserting the new basket 61 into the melting tank main body 10, the basket entrance/exit door 17' is closed. Next, open the exchange room door 18', hang the new basket 6j from the hook 1gbh of the hanging shaft 19b, then slide the lifting exchange device 19, and hang the new basket 6j from the hanging shaft 19a.
The suspended basket 6h is moved to the position of the basket exchange room entrance 18. After taking out the basket 6h from the exchange room 16, the basket exchange room door 18'
Close. Due to the above work.

The basket basket 61.6h containing the cleaned fuel shearing pieces 7 is carried out of the system, and a new empty basket 61.6j is carried into the system.

By repeating the above process operations, the fuel shear pieces 7 continuously enter the melting section lb and melt.

After going through a cleaning process, it leaves the dissolution tank. Also.

The solution is continuously supplied to the cleaning section 1a as a cleaning solution,
It is supplied to the melting section 1b through the communication pipe.

Further, it leaves the dissolution tank.

〔Effect of the invention〕

According to the present invention, two baskets containing nuclear fuel sheared pieces are
The rotary conveyance device moves the solution inside the annular dissolving tank, and -
After the cycle, the baskets are replaced one after another by the basket exchanger, so the sheared pieces are supplied, melted, and
Washing, removal of residual materials, etc. can be performed in parallel, and the dissolution process can be performed extremely efficiently.

In addition, when each basket is intermittently rotated by the two-rotation conveyance device, the baskets are taken in and out of the solution, so the solution that comes into contact with the sheared pieces is quickly replaced.
Dissolution reaction is promoted.

[Brief explanation of drawings]

FIG. 1 is a plan view of a dissolving tank according to an embodiment of the present invention, and FIG.
The figure is an elevational sectional view, Figure 3 is a plan sectional view, Figure 4 is a developed view of Figure 3, Figure 5 is a partially enlarged view of Figure 2, and Figure 6.7.
8.9 is an explanatory diagram of the operation of the above embodiment, and FIG. 10 is a sectional view of the conventional one. 10...Dissolution tank main body, la...Washing section, 1b...
Melting part, 1c... Gas phase part, 2... Fuel shearing piece supply chute, 3... Fuel shearing piece inlet door, 40... Rotary conveyance device, 41... Tower, 43... Basket Hanging equipment, 6
a to 6j... Basket, 44... Rotation drive device. 45... Vertical drive device Koma 1 Kunigu Yu 3A 2nd m 4th lwo

Claims (1)

[Claims] A tank body in which a solution reservoir formed in an annular shape is divided into a dissolving part and a cleaning part, and a plurality of holding members provided on the upper part of the tank body and selectively immersed in the dissolving part and the cleaning part. a basket member inserted for each holding member, a basket exchange device and a solution supply/drainage device provided above the tank body, spanning the starting point of the dissolution section and the cleaning section. An apparatus for melting irradiated nuclear fuel.