JPH0114958Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a cleaning device for fuel rods for a nuclear reactor.

For example, a nuclear reactor is loaded with fuel assemblies. As shown in Fig. 1, this fuel assembly consists of an upper nozzle 1 and a lower nozzle 2 which are vertically spaced apart and arranged in parallel, and a lattice-shaped nozzle arranged at a predetermined interval between them. A plurality of support grids 3 are inserted and supported at predetermined intervals in the grid spaces of the support grids 3, and the upper and lower ends are connected to the upper nozzle 1 and the lower nozzle 2, respectively, thereby forming the framework of the fuel assembly. a control rod guide tube 4, which is inserted into a predetermined lattice space of the support lattice 3, is elastically supported, and a plurality of fuel rods in which a large number of fuel pellets 6 and springs 7 are hermetically sealed in a cladding tube 5; It consists of 8.

By the way, a traceability label 9 is attached to this fuel rod 8 as shown in FIG.
A unique number for each fuel rod 8 is written on the traceability label 9 so that the production and inspection history of the fuel rod 8 can be traced. Therefore, when a fuel rod 8 that has passed the test is inserted into the grid space of the support grid 3 to assemble a fuel assembly, the traceability label 9 is peeled off and the remaining glue attached to the surface of the fuel rod 8 is removed. In order to remove the glue, the entire fuel rod 8, as well as the parts to which this glue has adhered, must be cleaned one by one using acetone and gauze.

However, in the past, this cleaning work was done manually, which could harm the health of workers by inhaling acetone gas, required a lot of manpower, and because acetone is easily flammable, it was difficult to prevent fire prevention. Since there was a need to take countermeasures, a significant improvement in this work was desired.

This idea was made in view of the above circumstances,
a transport mechanism for moving the fuel rods along their longitudinal directions; a first cleaning section main body and a second cleaning section body arranged in series along this movement path and each having a through hole surrounding the movement path of the fuel rods; a cleaning part body; a cleaning member consisting of a tubular felt plug whose inner diameter is approximately equal to the outer diameter of the fuel rod; the cleaning member is fitted into a through hole in the first cleaning part body; and a through hole in the first cleaning part body. a cleaning liquid tank that supplies cleaning liquid to the
By configuring the cleaning device with a wiping member consisting of a tubular felt plug whose inner diameter is approximately equal to the outer diameter of the fuel rod and which is fitted into the through hole of the second cleaning section main body, traceability labels can be peeled off. The glue adhering to the fuel rods after cleaning can be automatically cleaned and the cleaning liquid can be wiped off, resulting in significant cost reductions due to labor savings, protecting the health of workers, and reducing work irregularities. It is an object of the present invention to provide a fuel rod cleaning device that can prevent this from occurring.

An embodiment of this invention will be described below with reference to FIGS. 3 to 6. 11 in these figures is a cleaning case, which includes a stainless steel bottom plate 11a and a top plate 1.
1b and side plates 11c and 11d, it is formed into a box shape. The bottom plate 11a extends outward from the side plates 11c, 11c, and a guide roller 12 is horizontally and rotatably supported on one of the extensions of the bottom plate 11a via a bearing 13 and a shaft 14. There is. The guide roller 12 is made of polyurethane and has a number of grooves 12a circumferentially spaced at predetermined intervals and having a diameter substantially the same as the outer diameter of the fuel rod.

Further, on the bottom plate 11a, side plates 11c, 11c are provided.
A drive roller 15 is horizontally supported via a bearing 16 and a shaft 17 in parallel with the guide roller 12 . A groove 1 similar to the groove 12a of the guide roller 12 is provided on the outer periphery of the drive roller 15 in the circumferential direction.
A large number of grooves 5a are provided at the same intervals as the grooves 12a. Further, a rotating shaft of a motor 15b with a reduction gear attached to the cleaning case 11 is connected to one end of the shaft 17.

Above the drive roller 15, an upper roller 18 is provided with a predetermined gap between the drive roller 15 and the shaft 1.
9. It is disposed parallel to the drive roller 15 via a guide shaft 20 that passes through the top plate 11b so as to be vertically movable. The guide shafts 20 are connected at right angles to both ends of the shaft 19, and these two guide shafts 20 are connected by a bar 21. Also, bar 21
The intermediate portion of the cylinder mechanism 22 is connected to a piston rod 22a of a cylinder mechanism 22 vertically attached to the top plate 11b. Therefore, as the piston rod 22a moves up and down, the upper roller 18 also moves up and down via the bar 21, guide shaft 20, and shaft 19. A large number of grooves 18a similar to the grooves 15a of the drive roller 15 are provided on the outer periphery of the upper roller 18 in the circumferential direction at the same intervals as the grooves 15a.

Further, as shown in FIG. 4, a sprocket 23 is fitted to each of the driving rollers 15, 15, and a chain 24 is fitted to these sprockets 23.
is wound. Thereby, the two drive rollers 15, 15 are configured to rotate in conjunction with each other.

These drive rollers 15 and upper rollers 18 constitute a conveyance mechanism.

In addition, a bottom plate 25 is provided on the inner bottom surface of the cleaning case 11.
A plurality of rectangular dish-shaped support frames 26 and 27 are arranged in parallel with each other. Step portions 26a and 27a are formed at the upper ends of these support frames 26 and 27, respectively. At the upper part of the support frames 26 and 27, a first cleaning part main body 28 and a second cleaning part main body 29 are respectively fitted at their lower ends into step parts 26a or 27a, so that they cannot be moved in the horizontal direction and can be attached and removed in the vertical direction. (cassette type). Cleaning part body 2
8 and 29 are nylon thick plates, and the upper roller 18
in the direction perpendicular to the axis of the upper roller 1.
8. A large number of through holes 30 are formed at a height between the drive rollers 15. Each of these through holes 30
A tubular felt plug 31 is fitted and fixed therein. The inner diameter of these felt plugs 31 is slightly smaller than the outer diameter of the fuel rod. In addition, in the middle part of each through hole 30 in the length direction, a through hole 3 is provided in a downward shape.
A communication hole 3 that communicates between the inside of 0 and the inside of the support frames 26 and 27
2 is formed. A thread-like felt member 33 is inserted into the communication hole 32, and both ends of the felt member 33 are connected to the felt plug 31 and the support frame 2.
It has reached the bottom of 6,27.

Further, a cylinder mechanism 34 is vertically attached to the center of the cleaning case top plate 11b, and a presser metal fitting 35 is rotatably attached to the lower end of the piston rod 34a of the cylinder mechanism 34.
This presser metal fitting 35 is provided astride the cleaning section bodies 28, 29, and when the piston rod 34a of the cylinder mechanism 34 extends, these cleaning section bodies 28, 29,
29 can be simultaneously pressed downward and held on the support frames 26 and 27.

A transparent side plate 11e is attached to the left side of the cleaning case 11 in FIG. 3 and the bottom side in FIG.
It is hinged and attached to 1b. This allows the state of the felt plug 31 to be observed from the outside. Therefore, when the cylinder mechanism 34 is contracted, the pressing force of the presser metal fitting 35 on the cleaning section bodies 28 and 29 is released, and these can be taken out by rotating the transparent side plate 11e upward. ing.

Vertical holes 36, 37 are formed in both walls of the support frames 26, 27 in the longitudinal direction (left-right direction in FIG. 6) to communicate the inside and outside of the support frames 26, 27.

On the other hand, the cleaning liquid tank 3 is located at the top of the cleaning case 11.
8 is attached, and the bottom of the cleaning liquid tank 38 and the vertical hole 37 of one support frame 26 are connected to a conduit 39,
They are communicated via a valve 40. Further, the upper side wall of the cleaning liquid tank 38 and the vertical hole 36 of one of the support frames 26 are communicated via a conduit 41.

After filling the cleaning liquid tank 38 with a cleaning liquid (for example, acetone) and closing the lid 38a, when the valve 40 is opened, the acetone in the cleaning liquid tank 38 passes through the conduit 39 and accumulates in the support frame 26. When the depth of this acetone reaches h shown in FIG. 6, the upper surface of the acetone reaches the lower surface of the inner wall 26b of the support frame 26, so the support surrounded by the vacuum part and the inner wall 26b after the acetone in the cleaning liquid tank has come out. A balance is maintained between the pressure difference between the atmospheric pressure on the top surface of the acetone in the frame 26 and the weight of acetone at the height from the acetone surface in the support frame 26 to the top surface of the acetone in the cleaning liquid tank, and the outflow of acetone is stopped. . When this acetone is consumed through the felt member 33 and the felt plug 31 and the upper surface of the acetone inside the support frame 26 is lowered,
Air flows from the lower surface of the inner wall 26b into the cleaning liquid tank 38 through the conduit 41, and the pressure balance of the acetone in the cleaning liquid tank 38 is disrupted.
When the depth of the acetone in the support frame 26 reaches h, the acetone stops falling from the cleaning liquid tank 38. In this way, the acetone depth within the support frame 26 is always kept substantially constant.

Note that the cleaning section main body 29 is provided with a felt plug 31 and a felt member 33 like the cleaning section main body 28, but these are for wiping off acetone and are designed not to be impregnated with acetone.
That is, the felt plug 31 on the inlet side of the fuel rod in the direction of movement of the fuel rod is a cleaning member, and the felt plug 31 on the outlet side is a wiping member.

Next, the operation of the fuel rod cleaning device configured as described above will be explained.

(1) Fill the cleaning liquid tank 38 with a cleaning liquid such as acetone, cover the lid 38a, and close the upper roller 1.
8. Adjust the gap between the drive rollers 15 to a predetermined size.

(2) Open the valve 40 and connect the support frame 2 through the conduit 39.
Acetone is supplied into the support frame 26, and its depth within the support frame 26 is set to a predetermined depth h. This acetone passes through the felt member 33 to the felt plug 31.
moisten.

(3) Activate the motor 15b with a reducer to rotate the drive rollers 15, 15 in conjunction (both drive rollers 1
5 and 15 rotate synchronously).

(4) The tray 42 on which the fuel rods 8 are placed is arranged near the cleaning case 11 so that the axial direction of the fuel rods 8 faces perpendicularly to the guide rollers 12.

(5) Move the fuel rod 8 on the tray 42 to the right in FIG. Peel off 9.

(6) This fuel rod 8 is further moved to the right, and the right end portion of the fuel rod 8 is inserted into the spaces within the opposing grooves 15a and 18a of the drive roller 15 and the upper roller 18.

(7) Then, the fuel rod 8 is moved to the drive roller 1 of (6) above.
5. It is held between the upper rollers 18 and advances to the right in FIG. 5, and is inserted into the acetone-impregnated felt plug 31 in the cleaning section main body 28 to be cleaned.

(8) Next, the fuel rod 8 is inserted into the dry felt plug 21 in the cleaning section main body 29, and the attached acetone is wiped off.

(9) The fuel rod 8 further advances to the right in FIG. 5, and its right end is held between the right drive roller 15 and the upper roller 18, and is further sent out to the right and placed on a tray (not shown). be done.

(10) If the traceability label is not cleaned sufficiently, press the button (not shown)
By operation, the fuel rod 8 is reciprocated electrically with the peeling trace located within the felt plug 31 impregnated with acetone, thereby reliably cleaning it.

(11) After cleaning the fuel rods 8, the cylinder mechanism 3
4 is reduced to release the pressure of the holding fittings 35 on the cleaning section bodies 28 and 29, and the transparent side plate 11 is removed.
e, take out the dirty acetone-impregnated felt plug 31 side cleaning part main body 28 to the outside, and attach the unimpregnated felt plug side cleaning part main body 29 to the support frame 2.
6. Place it on top. On the support frame 27 is a cleaning section main body 29 with a new unimpregnated felt plug 31.
After placing the transparent side plate 11e, the cylinder mechanism 34 is operated to extend, and the presser metal fitting 35 presses the cleaning section main bodies 28, 29.

(12) Repeat steps (1) to (11) above.

Note that 45 is an exhaust port.

As explained above, according to this invention, there is a transport mechanism that moves the fuel rods along their longitudinal direction, and a through hole that is arranged in series along this movement path and that each surrounds the movement path of the fuel rod. a first cleaning part main body and a second cleaning part main body having a first cleaning part main body and a second cleaning part main body, and a cleaning member consisting of a tubular felt plug whose inner diameter is approximately equal to the outer diameter of the fuel rod and which is fitted into the through hole of the first cleaning part main body. , from a cleaning liquid tank that supplies cleaning liquid to the through hole of the first cleaning part main body, and a tubular felt plug whose inner diameter is approximately equal to the outer diameter of the fuel rod, which is fitted into the through hole of the second cleaning part main body. By configuring the cleaning device with a wiping member, it can automatically clean the glue adhering to the fuel rod after the traceability label has been peeled off, and can also wipe off the cleaning liquid, resulting in significant labor savings. It has the following effects: cost reduction, worker health, and prevention of uneven work.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view of the fuel assembly, Fig. 2 is an external view of the fuel rod, Fig. 3 is a vertical front view showing one embodiment of this invention, and Fig. 4 is a partially cutaway cross-sectional plane. 5 is a partially omitted cross-sectional view, and FIG. 6 is a diagram showing the state of acetone replenishment within the support frame. 11...Washing case, 15...Drive roller, 1
8... Upper roller, 26, 27... Support frame, 2
8, 29...Cleaning part main body, 30...Through hole, 31
...Felt plug, 32...Communication hole, 33...
Felt member, 38... Cleaning liquid tank, 39, 4
1... Conduit.

Claims (1)

[Scope of utility model registration request] a transport mechanism for moving the fuel rods along their longitudinal direction; a first cleaning section main body and a second cleaning section body arranged in series along this movement path and each having a through hole surrounding the movement path of the fuel rod; a cleaning part body; a cleaning member comprising a tubular felt plug whose inner diameter is approximately equal to the outer diameter of the fuel rod; the cleaning member is fitted into a through hole in the first cleaning part body; and a through hole in the first cleaning part body. a cleaning liquid tank that supplies cleaning liquid to the
A wiping member comprising a tubular felt plug whose inner diameter is approximately equal to the outer diameter of the fuel rod and which is fitted into the through hole of the second cleaning section main body.