JPS5827478B2 - How to transfer spent fuel - Google Patents

Description

Detailed Description of the Invention This invention provides a method for transferring spent fuel between a spent fuel storage boule and a cask in a nuclear power plant, spent fuel reprocessing plant, intermediate storage facility, etc. Regarding.

For the above facilities, spent fuel is transferred between storage boule and cask for transportation or storage, but since spent fuel has strong radioactivity, it is difficult to handle it properly. Consideration is required.

Conventionally, as shown in FIG.
The cask 2 is submerged in the water, and the spent fuel F is put into the fuel basket 3 inside the cask 2, or conversely taken out from the fuel basket 3.

However, this method does not require the use of radioactively contaminated boule 1.
There is a drawback that the water inside the cask 2 adheres to the inner and outer surfaces of the cask 2 and contaminates the cask 2.

Contamination of the outer surface of the cask 2 can be prevented by covering the cask 2 with a cover, but this is not preferable because not only is there a risk of contamination due to a defective cover, but the cover itself is also contaminated.

Furthermore, since the heavy cask 2 is handled underwater, there is a safety problem.

This invention was made in view of the above-mentioned circumstances, and an object thereof is to provide a method for transferring spent fuel that dramatically reduces contamination on the inner and outer surfaces of casks and allows safe handling of casks. shall be.

Hereinafter, this invention will be explained in detail based on the embodiments shown in FIGS. 2 and 3.

The drawing shows a spent fuel storage pool 10 and a spent fuel F transfer facility 11 provided adjacent to the boule 10 in order to carry out the present invention, and shows the connection between the boule 10 and the transfer facility 11. A first shielding wall 13 having the same height as the surrounding shielding body 12 is provided in between.

The transfer equipment 11 includes a water supply and drainage system storage cell 14 formed at the same depth as the boule 10, and a temporary fuel storage cell 15.
It has generally temporary cask storage cells 16 arranged in a line along the first shielding wall 13.

The water depth of the boule 10 is determined so that the fuel F is sufficiently submerged in water for shielding purposes when the fuel F is moved, which will be described later.

A second shielding wall 17 having the same height as the first shielding wall 13 is provided between the water supply and drainage system storage cell 14 and the fuel storage cell 150, and between the fuel storage cell 15 and the cask storage cell 16,
lower than the first and second shielding walls 13°17 and boule 1
A third shielding wall 18 higher than the water level at 0 is provided.

A fuel holding frame 19 for holding a large number of fuels F vertically is installed in the fuel storage cell 15.

On the first shielding wall 13 sandwiched between the boule 10 and the fuel storage cell 15, there is a vertically elongated fuel transfer gate 20 extending from a portion at approximately the same height as the upper end of the fuel holding frame 19 to the upper end of the shielding wall 13.
is formed, and a shielding door (path shown) is attached to this gate 20.

A vertically elongated fuel transfer gate 21 extending from a portion above the upper end of the fuel held in the fuel holding frame 19 to the upper end of the shielding wall 18 is formed on the third shielding wall 18 where the residue is removed. A shielding door (as shown) is also installed.

A horizontal shielding plate 22 is provided above the fuel storage cell 15 and the cask storage cell 16.

This horizontal shielding plate 22 is movable in the horizontal direction, and when pulled out to the right in the drawing, opens the upper part of each cell 15, 16, and is pulled upward (leftward) into each cell 15, 16. It is designed to shield each cell 15, 16 when it is exposed.

Further, a remote control crane 23 is provided between the lower surface of the horizontal shielding plate 22 and the upper end surface of the third shielding wall 18, and is capable of moving horizontally above the fuel storage cell 15 and the cask storage cell 16.

Then, the fuel storage cell 15 and the cask storage cell 16
A monitoring device consisting of an industrial television or the like is installed inside.

The water supply and drainage device storage cell 14 is equipped with a water supply and drainage device (path shown) that performs water supply and drainage of the fuel storage cell 15, as well as opening and closing of each game (20, 210).

Additionally, a crane (path shown) that can freely move above the boule 10 and the transfer equipment 11 is provided.

Water can be supplied to the fuel storage cell 15 by a water supply and drainage system.

Further, the gate 20 of the first shielding wall 13 can be closed to drain all or part of the water in the fuel storage cell 15.

Then, the water level inside the fuel storage cell 15 reaches the third shielding wall 18.
If the height is higher than the lower end of the gate 21, the gate 21 is closed to prevent water from flowing into the cask storage cell 16.

In the method of this invention, the operation for transferring the fuel F from the boule 10 to the cask 24 is as follows.

First, after closing the gate 21 of the third shielding wall 18 and the gate 20 of the first shielding wall 13 and supplying water to the fuel storage cell 15 by the water supply and drainage device, the gate 20 of the first shielding wall 13 is closed. It is opened and the fuel F in the boule 10 is transferred to the fuel storage cell 15 through water.

This operation is performed with the horizontal shielding plate 22 pulled out to the right.
This is done using a crane installed above the boule 10.

The fuel F is held vertically by a crane, passes through the gate 20, is charged into the holding frame 19 from above, and is held vertically.

Since the fuel F is thus moved through the water, even if the upper portions of the fuel storage cell 15 and cask storage cell 16 are open, there is no risk of the workers being exposed to radiation.

When the required number of fuels have been transferred to the holding frame 19, the gate 20 of the first shielding wall 13 is closed, the horizontal shielding plate 22 is pulled to the left, and the fuel storage cells 15 and cask storage cells 16 are closed.
The water in the fuel storage cell 15 is partially discharged.

Then, the water level is set to be lower than the lower end of the gate 21 of the third shielding wall 18 and higher than the fuel in the holding frame 19.

Next, the gate 21 of the third shielding wall 18 is opened and the fuel F in the holding frame 19 is transferred to the cask 24.

The cask 24 may be carried into the cask storage cell 16 before the horizontal shielding plate 22 is drawn in.

This operation is performed by operating the remote control crane 23 while monitoring the inside of both cells 15 and 16 using a monitoring device.

The fuel F is vertically gripped by the crane 23, transferred through the gate 21 above the cask 24, and charged vertically.

When the cask 24 is filled with fuel F, attach the lid 25 to it, pull out the horizontal shielding plate 22 to the right, and close the cask 24.
to be carried out.

When transferring fuel F from cask 24 to boule 10,
Just do the opposite of the above.

That is, after carrying the cask 24 containing fuel into the cask storage cell 16, the horizontal shielding plate 22 is pulled to the left to shield the fuel storage cell 15 and the cask storage cell 16, and the first shielding wall 13 is closed. After closing the gate 20 and draining some of the water in the fuel storage cell 15, the gate 21 of the third shielding wall 18 is opened, the lid 25 of the cask 24 is removed, and the fuel is transferred from the cask 24 to the holding frame 19. Third shielding wall 18
After closing the gate 21 of the first shielding wall 13 and supplying water to the fuel storage cell 15, the gate 20 of the first shielding wall 13 is opened and the horizontal shielding plate 5 is pulled out to the right to transfer the fuel from the holding frame 19 to the boule 10. .

In this embodiment, the fuel holding frame 19 is always installed in the fuel storage cell 15 and the fuel F is moved one by one between the fuel storage cell 15 and the cask 24. A plurality of fuels F may be moved at once using a fuel basket that can be loaded into the cask 24 while holding the fuels F.

In addition, fuel storage cell 15 and cask storage cell 16
When moving the fuel F between the fuel storage cell 15 and the cask 24 by shielding the fuel storage cell 15, all of the water in the fuel storage cell 15 may be discharged.

The spent fuel transfer method according to the present invention includes a temporary fuel storage cell 15 adjacent to the spent fuel storage boule 10.
A temporary cask storage cell 16 is provided adjacent to the fuel storage cell 15, and a temporary cask storage cell 16 is provided adjacent to the fuel storage cell 15.
Water is supplied to the cask storage cell 16 as needed, but water is not allowed to flow into the cask storage cell 16, and while water is supplied to the fuel storage cell 15, the boule 10 and the fuel storage cell 15 are The spent fuel is moved through water between the boule 10 and the fuel storage cell 15, and the required amount of water is discharged from the fuel storage cell 15 by blocking the connection between the boule 10 and the fuel storage cell 15. 16 is shielded, the spent fuel is moved between the fuel storage cell 15 and the cask 24 placed in the cask storage cell 16, thereby moving the spent fuel between the boule 10 and the cask 24. , so there is no need to immerse the cask 24 in the boule 10.

Therefore, contamination on the inner and outer surfaces of the cask 24 is reduced,
Moreover, the cask 24 can be handled safely.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view showing a conventional example, Figures 2 and 3.
The figures show an embodiment of this invention, FIG. 2 is a plan view of equipment used to carry out this invention, and FIG.
It is a sectional view taken along the −■ line. 10... Spent fuel storage boule 15... Fuel storage cell, 16... Cask storage cell 24... Cask, F... Spent fuel.

Claims (1)

[Claims] 1 A temporary fuel storage cell 15 is provided adjacent to the spent fuel storage boule 10, and this fuel storage cell 15
A temporary cask storage cell 16 is provided adjacent to the fuel storage cell 15, and water is supplied to the fuel storage cell 15 as needed, but water is not allowed to flow into the cask storage cell 16. With water supplied to cell 15, boule 1
The spent fuel F is moved through water between the boule 10 and the fuel storage cell 15, the gap between the boule 10 and the fuel storage cell 15 is cut off, and the required amount of water is discharged from the fuel storage cell 15. With the cask storage cell 16 shielded, the fuel storage cell 15 and the cask storage cell 1 are
A method for transferring spent fuel, in which spent fuel F is moved between boule 10 and cask 24 placed in boule 6, thereby moving spent fuel F between boule 10 and cask 24.