JPS5925480B2 - Cylindrical body processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nuclear fuel cylindrical body cutting device, and more particularly to a nuclear fuel cylindrical body cutting device that can reliably cut a nuclear fuel cylindrical body.

A fuel assembly is loaded in the core of a nuclear reactor.

The fuel assembly has a cylindrical body surrounding a plurality of fuel rods containing fissile material.

The cylindrical body of the fuel assembly used in boiling water reactors is called a channel box.

A channel box of a spent fuel assembly taken out from the core of a boiling water reactor is removed from the fuel assembly and stored.

However, since the inside of the channel box is hollow,
A large amount of space is required for storage.

For this reason, processing methods have been considered to reduce the volume of the channel box.

As an example of the channel box processing method,
There is a method described in Japanese Patent No. 3-27795.

This conventional processing method involves punching out a plurality of overlapping holes in the wall of a channel box to form a cutting line extending in the axial direction.

The mass punched out from the wall of the channel box for cutting is introduced into a storage container.

The punching operation of channel boxes is not easy.

The cut channel box pieces are also inserted into a separate dedicated storage container.

The channel box piece is moved into the storage container by holding it with a handling tool.

Even during the cutting operation of the channel box, the channel box is attached to the handling tool suspended from the hoist.

Thus, in the conventional method, handling of lumps and channel box pieces is not easy.

A nuclear fuel cylindrical body cutting device that can easily carry out cutting operations is described in Japanese Patent Application No. 1988-98189 filed in Japan.

This improved nuclear fuel cylinder cutting device consists of a casing into which the channel box removed from the spent fuel assembly is inserted, a pusher that presses and moves the channel box from the upper end of the casing toward the lower end, and a pusher inside the casing. A roller cutter continuously cuts the channel box in the axial direction as it descends.When the roller cutter is placed in the extension line of the roller cutter and the channel box can be cut by the roller cutter, the roller cutter continuously cuts the channel box in the axial direction. and a shear that cuts the cut portion in a direction intersecting the axial direction of the cut portion.

The improved nuclear fuel cylinder cutting device cuts the axially cut portion of the channel box along its axis when the roller cutter and shear are aligned and the roller cutter is ready to cut the channel box. Since the shear is further shredded in the direction crossing the direction,
There is no need for a special device to take out the four channel box pieces obtained by cutting the channel box in the axial direction, the cutting time until shredding is shortened, and the cutting work is extremely easy.

However, when cutting the channel box, the corner portion of the channel box facing the roller cutter may protrude outward, and the channel box may not be cut properly in the axial direction.

An object of the present invention is to provide a nuclear fuel cylindrical body cutting device that can effectively cut a cylindrical body in the axial direction.

The present invention is characterized by providing a casing into which the cylindrical body removed from the fuel assembly is inserted, and providing means for pressing and moving the cylindrical body from one end of the casing toward the other end, and moving the cylindrical body within the casing. A means for continuously cutting the cylindrical body in the axial direction is provided at the lower part of the casing, and a means for suppressing deformation of the cylindrical body by the cutting means when cutting the cylindrical body is provided opposite to the cutting means. The cylindrical body is arranged to form a gap between the cylindrical body and the means through which the cylindrical body passes.

Processing of a cylindrical body of a fuel assembly, for example, a channel box of a fuel assembly applied to a boiling water nuclear reactor, will be described.

A fuel assembly applied to a boiling water reactor includes a plurality of fuel rods arranged between an upper tie plate and a lower tie plate and having upper and lower ends attached to the upper and lower tie plates, and an upper tie plate. It consists of a spacer that is disposed between the lower tie plate and maintains a predetermined gap between the fuel rods, and a channel box that is attached to the upper tie plate and surrounds the fuel rod bundle.

A channel box is removed from a spent fuel assembly taken out from the core of a boiling water reactor.

After removing the triangular clips attached to the top corners of the channel box that attach the channel box to the top tie plate, the channel box
Cut axially.

The principle of axial cutting of a channel box (method described in Japanese Patent Application No. 53-98189), which is an improvement on the method disclosed in Japanese Patent Application Laid-open No. 53-27795, was explained based on FIGS. 1 and 2. This will be explained below.

1 and 2 show a roller cutter device 2. FIG.

The roller cutter device 2 consists of a main body 3 and a circular blade 5.

The circular blade 5 is inserted into a longitudinal groove 4 formed in the inner corner of the main body 3 and is rotatably attached to the main body 3 by a pin 6.

A plurality of circular blades 5 are installed in the axial direction of the main body 3.

The distance between the outer surfaces of a pair of circular blades 5 facing each other across the axis of the main body 3 is small near the top end of the main body 3 and large near the bottom end of the main body 3.

The lower end of the channel box 1, which has been removed from the spent fuel assembly as described above, is brought into contact with the upper end of the roller cutter device 2, as shown in FIG.

At this time, the roller cutter device 2 is inserted into the channel box 1.

Each of the circular blades 5 provided at the four corners of the main body 3 of the cutter device 2 faces the inner side of each ridgeline 7 existing at the corner of the channel box 1 having a square cross section.

The cutter device 2 is fixed. As the channel box 1 is moved downward, the plurality of circular blades 5 arranged in the axial direction of the main body 3 move toward the channel box 1.
The channel box 1 is cut from the inside along the ridge line 7 in the axial direction.

However, depending on the degree of radiation irradiation of the spent fuel assembly within the reactor, a phenomenon as shown in FIG. 3 may occur, and the channel box 1 may not be cut properly.

That is, the corner portion of the channel box 1 to be cut by the circular blade 5 cannot withstand the cutting force of the circular blade 5, and causes elastic deformation or plastic deformation, thereby causing a phenomenon in which the corner portion of the channel box 1 that is to be cut by the circular blade 5 tends to relatively escape from the circular blade 5. Occur.

Therefore, the corner portion of the channel box 1 that comes into contact with the circular blade 5 protrudes outward as shown at 9 in FIG. 3, and the ridgeline (corner portion) of the channel box 1 is not completely cut.

Methods to solve this problem include (1) a method of further increasing the diameter of the lower circular blade 5 in the axial direction of the roller cutter device 2; and (2) a method of further increasing the diameter of the lower circular blade 5 in the axial direction of the roller cutter device 2; There is a method of increasing the number of circular blades 5.

In the method (1), the cutting resistance force of the circular blade 5 increases and the cutting edge of the circular blade becomes easily damaged.

In method (2), some of the upper circular blades 5 do not lose their cutting function, and the structure of the roller cutter device 2 itself becomes larger.

As a result of various experiments, it was found that by using a constraint guide, the problems of methods (1) and (2) described above can be solved, and the channel box 1 can be cut smoothly in the axial direction.

The present invention has been made based on this result.

A preferred embodiment of the present invention will be described based on FIG.

The channel box cutting device 12 is inserted into and installed in the fuel storage pool 10 in which the cooling water 11 is present during fuel exchange work when the boiling water reactor is shut down.

The channel box cutting device 12 is pulled out of the fuel storage pool 10 after the processing of the channel box 1 is completed.

The channel box cutting device 12 includes a cutter device 2, casings 13, 14, 15, and 16, a shear 24, and a cut piece storage container 57.

Bottom surface 10 of fuel storage pool 10 filled with cooling water 11
A pedestal 19 is installed on A.

Opening 1 through which a cut piece storage container 57 with wheels 59 enters and exits
A casing 17 with 8 is fixed on a pedestal 19.

On the casing 17 the casings 16, 15, 14 and 13 are arranged in this order.

Casing 17 and casing 16 have flanges 17A and 1
6B, the casing 16 and the casing 15 are fixed by the flanges 16A and 15A, respectively.

The cutter device 2 shown in FIGS. 1 and 2 is arranged in the lower part of the casing 15.

A fixed blade holder 20 in the shape of a truncated quadrangular pyramid is attached to the main body 3 of the cutter device 2.
attached to the lower end of the

A fixed blade 21 is attached to the lower end of each side surface of the fixed blade holder 20, respectively.

A support portion 22 having a square cross-sectional shape and having a cross-sectional area smaller than the cross-sectional area of the lower end of the fixed blade holder 20 is attached to the lower end of the fixed blade holder 20.

Four support rods 23 are connected to the support part 22 as shown in FIG.
installed at each corner of the

The support rod 23 is attached to the casing 16 and fixes the support portion 22, that is, the cutter device 2 and the fixed pedestal 20.

The movable blades 25 of four shears 24 are arranged opposite to each fixed blade 21.

Each shear 24 is attached to the casing 16.

A shooter 26 is attached to the casing 16 below the support rod 23.

The four restraining guides 27, 28, 29 and 30 are the seventh
As shown in the figure, they are arranged opposite to the side surface of the main body 3 of the cutter device 2, and are attached to the inner surface of the casing 15, respectively.

A gap 31 exists between the restraining guides.

The circular blade 5 is oriented in the direction of the gap 31.

The channel box 1 is inserted into the gap formed between the main body 3 of the cutter device 2 and each constraint guide.

The gap A between the wall surface of the restraining guide and the outer wall of the channel box 1 has been adjusted to a predetermined dimension.

A suction pipe 32 is connected to the upper end of the casing 15.

Although not shown in detail, a pump 33 and a purification device (for example, a filter) 34 fixed to the wall of the fuel storage pool 10 are arranged in the suction pipe 32.

The drive unit base 37 is connected to the upper floor surface 5 of the fuel storage pool 10.
It is placed at 9.

Drive casing 40 is slidably attached to a drive guide 38 that is mounted on drive base 37 .

A handle 39 is attached to the drive guide 38.

The upper end of the casing 13 extending downward is attached to the drive device casing 40, and the casing 14 is attached to the lower part of the casing 13.

Casing 13 and casing 14 are fixed by flanges 13A and 14A.

A pusher fitting 46 is present within the casing 14 .

A plurality of guide rollers 47 are attached to the side surface of the pusher fitting 46.

A feed screw 45 is attached to the upper end of the push fitting 46.

The feed screw 45 passes through the casing 13 and reaches into the drive device casing 40 .

The lower part of the feed screw 45 is inserted into a sealing member 50 located below a pair of guide rollers 48 and guide rollers 48 provided in the casing 13 .

The guide roller 48 supports and centers the feed screw 45.

A speed reduction device 42 provided within the drive device casing 40 meshes with the outer periphery of a nut 43 attached to the feed screw 45.

The reduction gear (reduction gear) 42 is connected to the drive device casing 40
It is connected to the motor 41 inside.

44 is a stopper that prevents the nut 43 from moving in the axial direction.

In order to increase the rigidity of the casings 13, 14 and 15 and to obtain straightness when assembling the channel box cutting device 12, a guide rod 51 consisting of an upper guide rod 52 and a lower guide rod 54 is attached to the drive unit base 38. It will be done.

The upper guide rod 52 is fixed to the drive unit base 37, and the upper guide rod 52 and the lower guide rod 54 are joined via flanges 52A and 54A.

An arm 53 attached to the casing 13 is rotatably attached to the upper guide rod 52.

Arms 35 and 36 attached to casing 15 are attached to lower guide bar 54 via pins 55 and 56.

The cutting operation of the channel box 1 will be explained below.

A spent fuel assembly (not shown) taken out from the core of a boiling water reactor is transferred into a fuel storage pool 10 filled with cooling water 11.

Here, the Zircaloy channel box 1 having a length of about 4 m is removed from the fuel assembly by a channel attachment/detachment machine (not shown).

The channel box 1 is temporarily stored in a channel storage rack (not shown) within the fuel storage pool 10.

Hanging fitting 6 attached to rope 60 as shown in FIG.
1 is attached to the aforementioned pair of clips near the upper end of the channel box 1, and the channel box 1 is lifted up.

The channel box 1 is transported to the vicinity of the casing 15 of the channel box cutting device 12 while being suspended from a rope 61.

FIG. 8 shows this state. A handle 39 provided on a drive guide 38 mounted on the drive base 37
to raise the drive device casing 40.

Along with this, the casings 13 and 14 also rise at the same time.

When the casing 14 is raised a predetermined amount, the drive device casing 40 is pivoted about the drive device guide 38 in the direction of arrow 62.

The casing 14 is moved laterally from the upper end of the casing 15 such that the upper end of the casing 15 is in the fuel storage pool 10.
Open inward.

Thereafter, the channel box 1 suspended from the rope 60 is moved onto the casing 15.

The channel box 1 is inserted into the casing 15 while descending the rope 60.

The cross section of the casing 15 is square like the channel box 1, as shown in FIG.

After the insertion of the channel box 1 into the casing 15 is completed, the hanging fitting 61 is removed from the channel box 1 using tongs (not shown).

Thereafter, the clip attached to the upper end of the channel box 1 is removed from the channel box 1 using tongs (not shown).

The removed clip is housed within the aforementioned tongs and
It is taken out to the outside of the channel box cutting device 12.

The drive casing 40 is pivoted in the opposite direction of the arrow 62 and the casing 14 is moved onto the casing 15.

When the handle 39 is rotated in the opposite direction, the drive device casing 40 is lowered and the casing 14 comes into contact with the casing 15 (
(Situation shown in Figure 9).

After the alignment of the casings 14 and 15 is completed, the bundle 63 provided in the drive device casing 40
A rotating rod 64 connected to the bundle 63
The bolt wrench 65 provided at the lower end of the is rotated.

Through this operation, casing 14 and casing 15 are joined together.

Although not shown, the position of the upper end of the channel box 1 is confirmed using a detection device to confirm that the channel box 1 is inserted into the casing 15.

After confirming that the channel box 1 exists at a predetermined position within the casing 15, the motor 41 is driven.

The rotational force of the motor 41 is transmitted to a nut 43 whose outer periphery is a gear via a reduction gear 4z.

When the nut 43 rotates, the feed screw 45 also rotates, and the feed screw 45 descends.

The push-in fitting 46 descends as the feed screw 45 descends, and comes into contact with the upper end of the channel box 1 within the casing 15.

Furthermore, when the push-in fitting 46 descends, the channel box 1 is pushed down.

The casing 14 serves as a guide for lowering the channel box 1.

Since the lower end of the channel box 1 is in contact with the cutter device 29, as the channel box 1 is lowered,
Cuts are made along the ridge lines 7 existing at the four corners from the lower end of the channel box 1.

Each side wall of the channel box 1 is inserted between the cutter device 2 and the restraining guides 27, 28, 29 and 30.

Each restraint guide has the function of suppressing the side walls of the channel box 1, especially the side walls near the corners, from expanding outward when the ridge line 7 is cut by the circular blade 5, as shown in FIG. are doing.

That is, when the channel box 1 is cut in the axial direction along the ridge line 7 by the circular blade 5, each corner of the channel box 1 tends to be pushed outward due to the circular blade 5.

However, the side surfaces of the channel box 1 come into contact with each constraint guide, and the channel box 1 is prevented from being pushed outward by the constraint guides.

If the gap 31 formed between the restraining guides is too wide, it will not be possible to prevent the corner portions of the channel box 1 from being widened by the circular blades 5.

Therefore, it is preferable to make the gap 31 as narrow as possible within the range where the circular blade 5 can fit.

In this way, the channel box 1 is cut by the circular blade 5.

The restraint guides 27, 28, 29, and 30 are arranged in the axial direction of the casing 15 as shown in FIG.
It is placed only on the part facing the

Therefore, the gap between the casing 15 and the channel box 1 above the restraint guide is wider than the gap between the restraint guide and the channel box 1.

The channel box 1 of the spent fuel assembly is subjected to deformation during operation of the nuclear reactor.

However, since the gap between the casing 15 and the channel box 1 is wide, the deformed channel box 1 can sufficiently absorb the amount of deformation, and can descend smoothly.

The lower end of the channel box 1 that has been cut by the cut is pushed outward along the fixed blade holder 20 and descends to reach the inside of the casing 16.

Channel box 1 cut by cutter device 2
are four shears 2 installed opposite each fixed blade 21.
By moving each of the movable blades 25 of 4 in the direction of an arrow 66 intersecting the axial direction of the channel box 1, the channel box 1 is shredded into pieces having a length of about 150 mm in the axial direction.

Since the axially cut portion of the channel box 1 is spread out in all directions by the fixed blade holder 20, the aforementioned cut portions can be shredded simultaneously without interfering with the movable blades 25 of the four shears 24. can.

Further, since the impact forces from the shears 24 are simultaneously applied to the fixed blade holder 20 in opposite directions, the impact forces cancel each other out.

Therefore, the position of the axis of the fixed blade holder 20 does not shift or deform.

The cut pieces of the channel box 1 are passed through the chute 26 and stored in the cut piece storage container 57.

By cutting the channel box 1 into pieces as described above, the volume reduction ratio can be significantly improved.

During the cutting work of the channel box 1, the pump 33 is operated to suck the cooling water 11 inside the casing 15 into the piping 32.
Aspirate through.

Fine metal particles generated from the channel box 1 by cutting the channel box 1 by the roller cutter device 2 and shear 24 and peeled off iron cladding attached to the channel box 1 (iron cladding is mainly removed by the operation of the shear 24). The radioactive substances such as those that are peeled off can be removed from the casings 15, 16, and 17 by sucking out the cooling water 11 from the casing 15 using the suction pipe 32.

This is because the cooling water 11 flowing in from the opening 18 rises in the casings 17, 16, and 15 in sequence.

Each casing has the function of limiting the diffusion of metal particles and iron cladding.

Fine metal particles and iron cladding in the cooling water 11 flowing through the suction pipe 32 are removed by a purifier 34.

The cooling water 11 from which metal particles and the like have been removed is discharged into the fuel storage pool 10.

The amount of cooling water in the fuel storage pool 10 does not change.

The purifier 34 can remove all the fine metal particles generated by the cutting operation of the channel box 1 by the cutter device 2 and shear 24.

Fine metal particles with a high radioactivity level generated by the cutting operation can be prevented from diffusing into the fuel storage pool 9 as in the conventional method.

Although not shown, stoppers are provided on each side of the fixed blade holder 20 below the fixed blade 23.

The distance between the stopper and the fixed blade is approximately 150 mvt.

When the shear 24 is not performing cutting work, the stopper protrudes in all directions from the fixed blade holder 20 and supports the lower end of the portion of the channel box 1 that is being cut in the axial direction 1.

When performing cutting work with the shear 24, the stopper moves to the fixed blade holder 20 side and does not prevent the cut pieces of the channel box 1 from falling.

The stopper prevents the unshredded channel box 1 from falling.

When a predetermined amount of the cut pieces of the channel box 1 are stored in the cut piece storage container 57 having wheels 58, the cut piece storage container 57 is moved out of the casing 17 through the opening 18 and into the fuel storage pool 10. stored.

The upper part of the cut piece storage container 57 is sealed with a lid.

This can prevent crud and the like attached to the fragments present in the cut fragment storage container 57 from peeling off and diffusing into the fuel storage pool 10 during storage.

According to this embodiment, the axially cut plate (length: about 14 m, width: about 13 crIL) is removed from the casing housing the channel box 1 and transferred into the storage container, as in the conventional method. There is no need for this, and no lumps punched out from the channel box 1 are generated.
Only the shredded pieces are stored in the cut piece storage container 57.

The cut piece storage container 57 is transferred to the channel box cutting device 12.
Since it is only necessary to move the cut channel box 1 outside, handling of the cut channel box 1 is easy.

Unlike the conventional method, there is no need to provide two different types of storage containers, one for lumps and one for cut channel boxes, and the device is more compact than the conventional method.

The channel box 1 can be continuously cut in the axial direction by rotating the circular blade 5, and the axial cutting mechanism is extremely simple compared to the cutting mechanism that punches holes intermittently as in the conventional method. Allows for smooth cutting.

In particular, since the cutter device 2 and the shear 24 are arranged consecutively in the vertical direction, the following advantages arise.

Since the channel box 1 is not completely cut in the axial direction by the cutter device 2, but the cut portion is shredded by the shear 24, the time required for cutting is shortened.

No special equipment is required to take out the axially cut parts of the channel box 1.

Movement of the channel box 1 for cutting by the cutter device 2 and shear 24 is possible by movement of the pusher fitting 46.

Therefore, the channel box cutting device 12 becomes compact.

It is also conceivable that the cutter device 2 completely cuts the channel box 1 in the axial direction into four plates, and then the shear 24 shreds each plate.

However, in this case, it is necessary to take out each plate obtained by cutting with the cutter device 2 outside the casing and move each plate to the position of the shear.

Therefore, a moving device is required, which complicates the cutting operation of the channel box 1.

Additionally, the equipment becomes similarly complex.

In this embodiment, as described above, there is no need to take out the part of the channel box 1 cut by the cutter device 2 out of the casing, and it is only necessary to push down the channel box 1 with the pusher fitting 46, so the cutting of the channel box 1 is possible. The work is significantly simplified and cutting operations become easier.

Moreover, the cutting device 12 becomes compact.

Furthermore, what is important is that since the restraining guide is provided as described above, outward deformation of the side wall of the channel box 1 can be suppressed, and the channel box 1 can be cut smoothly in the axial direction.

In order to increase the distance between the outer surfaces of the pair of circular blades 5 of the cutter device 2 at the lower end of the main body 3, the diameter of the circular blades 5 is Instead of changing the diameter of the circular blade 5 as shown in FIG. 1, the mounting position of the pin 6 may be moved toward the outer peripheral edge of the main body 3 as it goes toward the lower end of the main body 3 while keeping the diameter of the circular blade 5 the same.

Further, the diameters of the plurality of circular blades provided in the cutter device 2 may be gradually increased from the upper end to the lower end of the main body 3.

Therefore, the distance also gradually increases from the top to the bottom.

The channel box 1 starts contacting from the side with the smaller distance.

By gradually increasing the distance from one end of the main body 3 to the other, the amount of cut into the channel box 1 can be equally distributed to all the circular blades arranged in the axial direction, and one circular This prevents a large load from being placed on the blade.

Therefore, the life of the circular blade is extended.

The top circular blade 5 may be used simply as a guide for the channel box 1.

Cutter device 2 like channel box cutting device 12
Even if a restraining guide is provided opposite to the channel box 1, there may be a portion (uncut portion) 67 at the upper end of the channel box 1 that is not cut in the axial direction by the circular blade 5, as shown in FIG.

The length of this uncut portion 67 is approximately 10 mm from the upper end of the channel box 1.

At the upper end of the channel box 1 at the end of the cutting process by the circular blade 5, the force that restrains the original shape of the channel box 1 itself becomes weaker, and the outward deformation of the corner of the channel box 1 becomes large.
The uncut portion 67 at the upper end is a restraint guide 27.28°29
and 30, and loses its resistance to the circular blade 5.

As a result, the aforementioned uncut portion 6γ escapes from the circular blade 5 and passes through the position of the circular blade 5 without being cut.

However, as shown in FIG.
Depending on the material properties (degree of embrittlement due to neutron irradiation in the nuclear reactor), one or more of the four corners of the channel box 1 completes cutting in advance, leaving the other corners intact.

When the degree of embrittlement of the channel box 1 due to irradiation is large, the channel box 1 is separated into four plates without leaving an uncut portion 67 at the upper end thereof.

That is, when the cutting in the axial direction of the channel box 1 is progressed by the circular blade 5 and the cut reaches near the upper end of the channel box 1, the degree of embrittlement of the channel box 1 is large, so that the area near the remaining ridge line γ is cut. A crack appeared and the channel box 1 was separated into four plates.

A channel box cutting device 70 that can completely cut the channel box 1 in the axial direction without producing the aforementioned uncut portion 67 will be explained based on FIGS. 11 and 12.

FIG. 11 shows a portion corresponding to the section 2--2 in FIG. 5.

The channel box cutting device 70 is obtained by adding a circular blade 71 to the channel box cutting device 12 described above.

Components that are the same as those of the channel box cutting device 12 are indicated by the same reference numerals, and the structure of the channel box cutting device 70, which is not shown in FIGS. 11 and 12, is the same as the channel box cutting device 12.

A circular blade 71 is provided within the gap 31 formed between the restraining guides.
is placed.

The circular blade 71 has a pin 7 fixed to an adjacent restraint guide.
2 is rotatably mounted.

The circular blade 71 is arranged in the axial direction of the main body 3 at a position slightly above the lowest circular blade 5A attached to the cutter device 2.

The diameter of the circular blade 71 is larger than the diameter of the circular blade 5A.

The channel box 1 inserted into the casing 15 is lowered with the lowering of the pusher 46, inserted between the cutter device 2 and the restraint guide, and gradually cut along the ridge line 7 by the circular blade 5. .

The phenomenon in which the corner portions of the channel box 1 are pushed outward as shown in FIG. 3 during cutting is suppressed by the restraint guide, as in the embodiment described above.

The channel box 1 moves in the direction of arrow T3 and the cutting progresses, and the upper end 1A of the channel box 1
As shown in Fig. 2, when the cutter device 2 is reached, the outward deformation of the corner near the upper end of the channel box 1 is restrained by the circular blade 71, so that the circular blade 5A located at the bottom completely deforms the corner. is cut off.

Therefore, as shown in FIG. 10, an uncut portion 67 does not occur near the upper end of the channel box 1.

−; A rotating roller is arranged in place of the circular blade 71,
The corner portions of the channel box 1 may be restrained from the outside.

It is also possible to provide a plurality of circular blades 71 in the axial direction.

This embodiment can also achieve the same effects as the embodiments described above.

As shown in FIG. 13, the middle upper part of the circular blade 71 is
It may be located slightly below the center of A.

It is also possible to attach a cutter device using a circular blade 5 to the casing 15, and use the circular blade 5 to cut the channel box 1 from the outside of the channel box 1 in the axial direction along the ridge line 7 of the channel box 1.

However, in this case, compared to the embodiment shown in FIG. 4, the cross-sectional shape of the lower end of the casing 15 becomes larger, the shape of the casing 15 becomes more complicated, and the channel box cutting device becomes larger.

When applying the embodiment shown in FIG. 4 to the treatment of a wrapper tube (cylindrical body) of a fuel assembly for a fast reactor, since the wrapper tube has a hexagonal cross section, the cross-sectional shape of the casing 15 should be hexagonal. , it is necessary to arrange six circular blades of the cutter device in the same cross section.

According to the present invention, the cylindrical body of the fuel assembly can be cut in the axial direction, and the cutting operation of the cylindrical body is easy.

[Brief explanation of drawings]

FIG. 1 is a side view of a cutter device applied to the present invention, and FIG.
The figure is a sectional view taken along the line ■-■ in Figure 1, and Figure 3 is an explanatory diagram showing how the channel box is cut by the cutter device in Figure 1.
FIG. 4 is a vertical sectional view of a channel box cutting device which is a preferred embodiment of the present invention, FIG. 5 is an enlarged view of the vicinity of the cutter device in FIG. 4, and FIG. 6 is a cross section taken along VI-Vl in FIG. 5. 7 is a sectional view taken along the line ■-■ in FIG. 5, FIG. 8 is an explanatory diagram showing the state in which the channel box is inserted into the channel box cutting device in FIG. 4, and FIG. 9 is a cross-sectional view taken along・A state diagram showing a state in which the channel box has been completely accommodated in the Jannel box cutting device; FIG. The fifth channel box cutting device is
Figure 12 is a cross-sectional view of the part corresponding to the ■-■ cross section in the figure, Figure 12 is a cross-sectional view taken along ■-■ in Figure 11, and Figure 13 is a vertical cross-sectional view of another structure shown in Figure 12 on the stream side. It is. 1... Channel box, 2... Roller cutter device, 5... Circular blade, 7...
・Ridge line, 10...Fuel storage pool, 12...
...Channel box cutting device, 13, 14, 15
, 16.17...Cage; Ng, 24...
... Shear, 27, 28, 29, 30 ... Restraint guide, 34 ... Purifier, 41 ...
Motor, 45...Feed screw, 46...
Push-in fitting, 57... Cut piece storage container.

Claims (1)

[Scope of Claims] 1. A casing into which a cylindrical body removed from a fuel assembly is inserted, means for pressing and moving the cylindrical body from one end of the casing toward the other end, and a means provided at a lower part of the casing. a gap through which the cylindrical body passes between a roller cutter that continuously cuts the cylindrical body in the axial direction and a roller cutter that faces the roller cutter; A nuclear fuel cylindrical body cutting device comprising: a restraining guide arranged to form a cylindrical body and suppressing deformation of the cylindrical body by the roller cutter when the cylindrical body is cut. 2. A gap formed between an outer wall surface of the cylindrical body inserted into the casing above the constraint guide and an inner wall surface of the casing, wherein the constraint guide is disposed in a portion facing the roller cutter. The nuclear fuel cylindrical body cutting device according to claim 1, wherein the gap is wider than the gap formed between the outer wall surface of the cylindrical body and the restraint guide. 3. A casing into which a cylindrical body removed from a fuel assembly is inserted, a means for pressing and moving the cylindrical body from one end of the casing toward the other end, and a means provided at a lower part of the casing to move the inside of the casing. a roller cutter that continuously cuts the moving cylindrical body from the inside in the axial direction;
disposed opposite to the roller cutter so as to form a gap between the roller cutter and the roller cutter, through which the cylindrical body passes;
A restraining guide is installed in the casing at a position substantially opposite to the roller cutter to suppress deformation of the cylindrical body by the roller cutter when cutting the cylindrical body, and is installed at a position substantially opposite to the roller cutter in the casing, and suppresses deformation caused by the roller cutter when cutting the cylindrical body. A nuclear fuel cylindrical body cutting device consisting of a rotating body that is restrained from the outside. 4. A plurality of the roller cutters are arranged in the axial direction of the cylindrical body, and the diameter of the rotating body is set to be greater than or equal to the diameter of the roller cutter located at the farthest position from the suppressing movement means. The nuclear fuel cylinder cutting device described above.