JP2009122075A - Apparatus and method for cutting radioactive waste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radioactive waste cutting apparatus capable of cutting radioactive waste of different shapes and thicknesses in both vertical and horizontal directions, and of not producing secondary waste at cutting, and to provide a method for the apparatus. <P>SOLUTION: The radioactive waste cutting apparatus 1 includes: a cutting unit including a bandsaw 30, a vertical drive mechanism 12, which relatively moves the bandsaw 30 and one side of radioactive waste with respect to the other side in the vertical direction which is the longitudinal direction of the radioactive waste; a horizontal drive mechanism 13, which relatively moves the bandsaw 30 and one side of the radioactive waste against the other side in the horizontal direction, orthogonal to the vertical direction; and a cutting direction switching mechanism, having a guide 41 for switching the cutting direction of the bandsaw 30 between the vertical and horizontal directions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an apparatus for cutting radioactive waste and a method for cutting radioactive waste for volume reduction (volume reduction) of the radioactive waste.

  Conventionally, radioactive wastes such as used control rods (see Fig. 3 in the embodiment) and spent fuel channel boxes (also see Fig. 4) generated at nuclear power plants have extremely high radioactivity levels. And usually stored in water (in the pool). However, the used control rod has a long shape and a cross-section, and the used channel box has a long box shape (square tube shape). The storage efficiency is poor when stored in Therefore, in order to increase the storage efficiency, the volume of the used control rod and the spent fuel channel box is generally cut and reduced.

  For example, the used control rod of FIG. 3 is cut in the lateral direction (direction orthogonal to the length direction) to separate the speed limiter portion 3b at the lower end, and then the remaining cross-shaped main body portion 3a is removed. By cutting in the longitudinal direction (length direction) at the center of the cross shape, the cross section is separated into two L-shaped pieces having an L-shaped cross section. Further, the used channel box of FIG. 4 is separated into two L-shaped pieces having an L-shaped cross section by cutting in the vertical direction at two corners at diagonal positions of the square tube. Thus, if the used control rod and the spent fuel channel box are separated into L-shaped pieces, a large amount of waste can be stored in a small space by stacking these L-shaped pieces.

  Various apparatuses or methods have been proposed for cutting radioactive waste (see, for example, Patent Documents 1 to 6). Patent Document 1 discloses an apparatus capable of cutting radioactive waste suspended from a hanging tool in a vertical direction and a horizontal direction by a cutting torch such as a plasma arc. This cutting device cuts the radioactive waste in the vertical direction by moving the radioactive waste suspended by the hanger vertically with respect to the cutting torch. Moreover, radioactive waste is cut | disconnected in a horizontal direction by horizontally moving with respect to a cutting torch, rotating a radioactive waste to the surroundings of an axis | shaft.

  In Patent Document 2, water mixed with an abrasive is sprayed from a nozzle at a high pressure (water jet) with respect to the radioactive waste held in the cut object holding device, and this nozzle is applied to the radioactive waste. An apparatus for cutting a radioactive waste in a vertical direction by moving it in the vertical direction is disclosed.

  In Patent Document 3, the radioactive waste is moved in the vertical direction by moving the radioactive waste in the vertical direction by the transport device while irradiating the laser light while jetting the assist gas from the cutting nozzle. An apparatus for cutting is disclosed.

  In Patent Document 4, a spent fuel channel is formed by pressing a cutting blade, which is disposed inside a box-shaped (square cylinder) spent fuel channel box, extending in the longitudinal direction of the channel box from the inside with a cylinder. An apparatus is disclosed in which a box is cut longitudinally at two corners at diagonal positions and separated into two L-shaped pieces.

  In Patent Document 5, a plurality of holes are punched out from four corners of a box-shaped spent fuel channel box to cut the spent fuel channel box in the vertical direction at each of the four corners. An apparatus for separating into two long plate-like pieces is disclosed.

  Patent Document 6 discloses a cutting device having a vertical cutting nozzle for cutting radioactive waste in the vertical direction and a horizontal cutting nozzle for cutting the radioactive waste in the horizontal direction (direction perpendicular to the length direction). Is disclosed. In this cutting apparatus, first, radioactive waste is laterally rotated by rotating the radioactive waste around an axis while jetting water mixed with an abrasive to the radioactive waste at a high pressure from the horizontal cutting nozzle. Cut in the direction. Next, the radioactive waste is moved in the vertical direction by moving the radioactive waste in the vertical direction while spraying the water mixed with the abrasive at high pressure from the vertical cutting nozzle. To do.

JP-A 63-88500 JP-A-8-285996 JP 2003-28990 A JP 62-257093 A JP-A-53-27795 JP 2001-4785 A

  Since the apparatus of patent document 1 cuts radioactive waste by electric cutting, such as a plasma arc, it uses gas at the time of cutting. Therefore, in order to prevent the influence of gas from reaching the surroundings, a partition wall that surrounds the entire apparatus in water is required, and an off-gas treatment facility is required. In addition, an off-gas filter that cleans the gas generated during cutting is required as a consumable item. As a result, it is essential to replace the off-gas filter, and there is also a problem that the operator is exposed to radiation during the replacement.

  The apparatus of Patent Document 2 ejects water mixed with an abrasive from a nozzle to cut radioactive waste, so that sludge-like secondary waste containing the abrasive is generated, and it is troublesome to remove it. There is a problem that it takes.

  The apparatus of Patent Document 3 is the same as the apparatus of Patent Document 1 described above, such as the need to replace the off-gas filter by using gas because the radioactive waste is cut with a laser while jetting the assist gas from the cutting nozzle. Problems arise.

  Although the device of Patent Document 4 is suitable for cutting corners of a box-shaped spent fuel channel box, the radioactive waste having a shape other than the box-shaped shape, for example, a cross-shaped used one is used. It cannot be applied to the case where the control rod is cut in the longitudinal direction at the cross-shaped central portion.

  Since the apparatus of Patent Document 5 cuts radioactive waste by punching a plurality of holes, a large amount of punched pieces with small dimensions are generated, and it takes time to process them. In addition, since the wear of the punching blade is large, it is difficult to cut the radioactive waste having a large thickness. In particular, it is not suitable when a used control rod having a cross-shaped cross section is cut in the vertical direction at the center of the cross having a large thickness.

  The apparatus of Patent Document 6 requires two nozzles, a vertical cutting nozzle for cutting radioactive waste in the vertical direction and a horizontal cutting nozzle for cutting in the horizontal direction, which complicates the configuration of the apparatus and provides maintenance. It takes time and effort. In particular, maintenance of the transverse cutting nozzle fixedly provided at the lower part of the apparatus located at the bottom of the pool becomes very difficult. Furthermore, since radioactive waste is cut by jetting water mixed with abrasives from the nozzle at high pressure, sludge-like secondary waste containing abrasives is generated as in the apparatus of Patent Document 2. Problems also arise.

  An object of the present invention is to cut a radioactive waste having various shapes and thicknesses in a longitudinal direction and a lateral direction, respectively, and further, a radioactive waste cutting device that generates less secondary waste during cutting, and It is to provide a cutting method.

Means for Solving the Problems and Effects of the Invention

A radioactive waste cutting apparatus according to a first aspect of the present invention is a radioactive waste cutting apparatus for cutting radioactive waste that is long in one direction in water,
Cutting means including a band saw, vertical driving means for moving one of the band saw and the radioactive waste relative to the other in the vertical direction which is the length direction of the radioactive waste, the band saw and the radioactive waste Lateral drive means for moving one of the objects relative to the other in a lateral direction perpendicular to the longitudinal direction of the radioactive waste;
A cutting direction switching means for switching a cutting direction of the band saw between the vertical direction and the horizontal direction is provided.

  According to the configuration of the present invention, the cutting direction switching means switches the cutting direction of the band saw (the direction of the portion directly cutting the radioactive waste) to the vertical direction or the horizontal direction, and then the vertical direction driving means or the horizontal direction driving means. Accordingly, the radioactive waste can be cut in the vertical direction and the horizontal direction by relatively moving the band saw and the radioactive waste along the cutting direction (longitudinal direction or lateral direction) of the band saw. In other words, since both a vertical cutting and a horizontal cutting can be performed with one band saw, the apparatus configuration is simplified, and maintenance work such as replacement of the band saw is also simplified.

  In addition, the band saw can easily cut radioactive waste having various shapes and thicknesses (for example, a cross-shaped central portion of a used control rod having a large thickness). In addition, in comparison with other types of cutting methods, cutting with a band saw has a small cutting width and a small cutting amount per blade, so that the cutting reaction force is small. Therefore, there is an advantage that the radioactive waste can be reliably fixed with a small clamping force, and the clamping device for fixing the radioactive waste can be reduced in size.

  Further, in mechanical cutting using a band saw, there is no gas generation in plasma arc cutting (Patent Document 1) or laser cutting (Patent Document 3), no partition is required, and work such as replacement of an off-gas filter does not occur. . Further, there is no generation of sludge-like secondary waste in cutting (Patent Documents 2 and 6) with high-pressure water (water jet) mixed with an abrasive. Therefore, compared with the conventional one, the cutting device is compact, so that the installation work is facilitated, and the effect of reducing the running cost by simplifying the maintenance work can be obtained.

  In the radioactive waste cutting device according to a second aspect of the present invention, in the first aspect, the cutting direction switching means changes the direction of the band saw by rotating the guide member that guides the band saw and the guide member. And a rotation driving means.

  According to this configuration, the direction of the band saw at the portion facing the radioactive waste is easily changed between the vertical direction and the horizontal direction simply by rotating the guide member that guides the band saw by the rotation driving means. (Switch).

  According to a third aspect of the present invention, there is provided the radioactive waste cutting apparatus according to the second aspect, wherein the two guide members are arranged at positions symmetrical to each other with respect to the radioactive waste to be cut. Is.

  According to this configuration, the portion of the band saw that directly cuts the radioactive waste is guided from both sides by the two guide members, so that the radioactive waste can be stably cut by the band saw.

A radioactive waste cutting device according to a fourth aspect of the present invention is a radioactive waste cutting method for cutting radioactive waste that is long in one direction in water,
A band saw is cut in a longitudinal direction, which is the length direction of the radioactive waste, and then one of the band saw and the radioactive waste is moved relative to the other in the longitudinal direction to thereby form the radioactive waste. A longitudinal cutting step of cutting in the longitudinal direction;
The cutting direction of the band saw is oriented in a lateral direction orthogonal to the longitudinal direction, and then one of the band saw and the radioactive waste is moved relative to the other in the lateral direction, and the radioactive waste is moved to the lateral direction. A transverse cutting process to cut in the direction;
It is characterized by having.

  According to the cutting method of the present invention, the same operation and effect as the cutting device according to the first aspect of the present invention can be obtained. That is, by switching the cutting direction of the band saw, both the vertical cutting and the horizontal cutting can be performed with one band saw, and maintenance work such as replacement of the band saw is simplified.

  In addition, by using a band saw for cutting radioactive waste, it is possible to easily cut radioactive wastes of various shapes and thicknesses (for example, a thick central cross of the used control rod). . Further, since the cutting reaction force is small, the radioactive waste can be reliably fixed with a small clamping force. Further, in mechanical cutting using a band saw, there is no generation of gas in plasma arc cutting or laser cutting, or generation of sludge-like secondary waste in water jet cutting.

The radioactive waste cutting method according to a fifth aspect of the present invention is the radioactive waste cutting method according to the fourth aspect, wherein the radioactive waste is provided at the cross-section of the cross section parallel to the lateral direction and at one end in the length direction of the main body. And a used control rod having a speed limiter portion,
In the longitudinal cutting step, the cross-shaped central portion of the main body of the used control rod is cut along its length direction, and the main body is separated into two L-shaped pieces,
In the transverse cutting step, the main body portion and the speed limiter portion of the used control rod are cut and separated from each other.

  Thus, when the radioactive waste to be cut is a used control rod, in the longitudinal cutting step, the cross-shaped main body portion is cut in the longitudinal direction at the cross-shaped central portion, and in the lateral cutting step, The main body and the speed limiter provided at the end of the main body are separated. Accordingly, the used control rod can be separated into the main body portion and the speed limiter portion, and the main body portion having a cross-shaped cross section can be further divided into two L-shaped pieces having an L-shaped cross section.

According to a sixth aspect of the present invention, there is provided a radioactive waste cutting method according to the fourth aspect, wherein the radioactive waste is a spent fuel channel box having a rectangular cylindrical shape,
In the longitudinal cutting step, a corner portion of the spent fuel channel box is cut along its length direction, and the spent fuel channel box is cut into two L-shaped pieces or four long plate-like pieces. It is characterized by separating.

  As described above, when the radioactive waste to be cut is a rectangular cylindrical spent fuel channel box, the corner of the spent fuel channel box is cut in the length direction (vertical direction) in the longitudinal cutting step. By doing so, the spent fuel channel box is separated into two L-shaped pieces or four long plate-like pieces. In addition to this vertical cutting process, the length of the L-shaped piece or the long plate-shaped piece can be shortened by performing a horizontal cutting process.

  Next, an embodiment of the present invention will be described. FIG. 1 is a perspective view of a radioactive waste cutting apparatus 1 (hereinafter simply referred to as a cutting apparatus 1) according to the present embodiment, and FIG. 2 is a side view of the cutting apparatus 1. 1 are defined as up, down, front, back, left, and right, respectively.

  The cutting device 1 shown in FIGS. 1 and 2 is installed in a pool filled with water. And, long radioactive waste (specifically, used control rod 3 (FIG. 3) and used fuel channel box 4 (FIG. 4)), which is highly radioactive waste generated at nuclear power plants, Cut in this pool (underwater).

  Before describing the cutting device 1, the spent control rod 3 and the spent fuel channel box 4 which are radioactive wastes cut by the cutting device 1 will be described first. As shown in FIG. 3, the used control rod 3 includes a main body 3a having a cross-shaped cross section orthogonal to the length direction, and a speed limiter provided at one end (lower end) in the length direction of the main body 3a. Part 3b. When the volume of the used control rod 3 is reduced, the cutting device 1 first sets the used control rod 3 in the length direction (longitudinal direction) at the position of line AA in FIG. It cuts in the orthogonal direction (lateral direction), and separates the upper body part 3a and the speed limiter part 3b at the lower end. Further, at the position of the cross-shaped central portion 3c (the position of the BB line), the main body portion 3a is cut in the length direction (vertical direction), and two L-shaped pieces 5 having an L-shaped cross section (FIGS. 5 and 5). 6).

  As shown in FIG. 4, the spent fuel channel box 4 has a quadrangular cylindrical outer shape, and two clips 4a and two spacers 4b are provided at the upper end portion thereof. When the volume of the spent fuel channel box 4 is reduced, two corners at the diagonal position of the spent fuel channel box 4 are cut in the vertical direction (the position of the line CC in FIG. 4). ) Cut into two L-shaped pieces 5 having an L-shaped cross section (see FIGS. 5 and 6). Alternatively, all four corners may be cut in the vertical direction and cut into four long plate-like pieces.

  As shown in FIGS. 5 and 6, the L-shaped piece 5 obtained by cutting the used control rod 3 or the used fuel channel box 4 is compact in the storage box 2 in a state where a plurality of L-shaped pieces 5 are stacked. Can be accommodated. Even when the spent fuel channel box 4 is cut into four long plate-like pieces, a plurality of long plate-like pieces can be stacked and accommodated in the storage box 2. The speed limiter 3b of the used control rod 3 separated from the main body 3a is accommodated in a separate storage box from the L-shaped piece 5.

Next, the cutting device 1 will be described in detail.
As shown in FIGS. 1 and 2, the cutting apparatus 1 includes a main body frame 10, a cutting unit 11 (cutting means) that cuts radioactive waste installed in a vertical posture in the main body frame 10, and a cutting unit 11. The vertical movement mechanism 12 (longitudinal drive means) that moves the slab in the vertical direction (the length direction of the radioactive waste: vertical direction) and the horizontal that moves the cutting unit 11 in the horizontal direction (horizontal direction orthogonal to the vertical direction) A direction moving mechanism 13 (lateral driving means) and a clamping device (main clamping device 52 and auxiliary clamping device 53) for fixing radioactive waste to be cut are provided. FIG. 1 shows a state in which used control rods 3 having a cross-shaped cross section are installed as radioactive waste.

  The main body frame 10 includes a main frame 15, an upper frame 16 fixed to the upper end portion of the main frame 15, a lower frame 17 fixed to the lower end portion of the main frame 15, and the like. Further, a door 18 for carrying in and carrying out radioactive waste is attached to one side surface (front side in FIG. 1) of the main frame 15 so as to be openable and closable. However, it is not always necessary to carry in and carry out radioactive waste from the side surface of the main frame 15, and it may be carried in and out from above the main frame 15. In this case, the door 18 is unnecessary.

  On the back of the main frame 15, there is provided a mounting hook 20 for fixing the cutting device 1 to the side wall of the pool. The upper and lower ends of the four guide shafts 19 extending in the vertical direction are fixed to the upper frame 16 and the lower frame 17, respectively. A horizontal elevating base 21 is attached to these four guide shafts 19 so as to be movable in the vertical direction (vertical direction). A cutting unit 11 is provided on the upper surface of the lifting base 21.

  The elevating base 21 is driven in the vertical direction (vertical direction) by the vertical driving mechanism 12. Specifically, the vertical drive mechanism 12 includes a lift rod 22 connected to the lift base 21 and a drive unit 23 connected to the lift rod 22 and including appropriate drive means such as a motor. The elevating rod 22 is moved up and down by the drive unit 23 to move the elevating base 21 (cutting unit 11) connected to the lower end of the elevating rod 22 in the vertical direction (vertical direction). The vertical drive mechanism 12 is not limited to the one that drives the elevating base 21 up and down by raising and lowering the elevating rod 22 as described above, and other known mechanisms such as a screw mechanism and a chain mechanism are used. The elevator base 21 may be driven in the vertical direction.

  7A is a top view of the cutting unit 11, and FIG. 7B is a sectional view taken along line VIIa-VIIa of FIG. As shown in FIGS. 1, 2, and 7, the cutting unit 11 includes a band saw mounting base 31 disposed on the upper surface of the elevating base 21 and a band saw 30 attached to the band saw mounting base 31. As shown in FIG. 2, the band saw mounting base 31 is arranged on the upper surface of the lifting base 21 so as to be movable in the front-rear direction with respect to the lifting base 21 via two rollers 32. A lifting prevention stopper (not shown) is provided on the lifting base 21 so that the band saw mounting base 31 does not float with respect to the lifting base 21 during cutting. Further, as shown in FIG. 2, the band saw mounting base 31 is driven in the front-rear direction (lateral direction) by the lateral direction drive mechanism 13 (lateral direction drive means). Specifically, the lateral drive mechanism 13 has a fluid pressure cylinder 33 (for example, an air cylinder) connected to the band saw mounting base 31, and the rod of the fluid pressure cylinder 33 advances and retracts in the front-rear direction. The band saw mounting base 31 (that is, the cutting unit 11) is moved in the lateral direction (front-rear direction) with respect to the lifting base 21.

  On the upper surface of the band saw mounting base 31, two main pulleys 34 having an equal diameter and one auxiliary pulley 35 are rotatably provided. An endless band saw 30 (band saw) is stretched over the two main pulleys 34 and the one auxiliary pulley 35. As shown in FIG. 7B, a blade portion 30 a is formed on the end surface on one side in the width direction of the band saw 30. A band saw drive motor 36 is connected to one main pulley 34, and the main pulley 34 is rotationally driven by the band saw drive motor 36, so that the band saw 30 spanned between the three pulleys 34 and 35 travels.

  As described above, as shown by a solid line and a chain line in FIG. 2, the lifting base 21 provided with the cutting unit 11 including the band saw 30 is attached to the main body frame 10 by the vertical driving mechanism 12. It is driven in the vertical direction. Further, the band saw mounting base 31 to which the band saw 30 is attached is driven in the front-rear direction with respect to the lifting base 21. Accordingly, the band saw 30 is driven in the vertical direction (vertical direction) with respect to the radioactive waste by the vertical direction driving mechanism 12, and laterally (in the longitudinal direction) with respect to the radioactive waste by the horizontal direction driving mechanism 13. Will be driven.

  Further, the cutting apparatus 1 of the present embodiment includes two cutting direction switching mechanisms 40 (cutting direction switching means) that switch the cutting direction of the band saw 30 between the vertical direction (vertical direction) and the horizontal direction (horizontal direction). I have. As shown in FIGS. 7 to 9, the two cutting direction switching mechanisms 40 each include a guide member 41 that guides the band saw 30 and a fluid pressure cylinder 42 (rotation driving means) that rotationally drives the guide member 41. Have.

  As shown in FIGS. 7 and 8, the two guide members 41 are arranged between the two main pulleys 34 with an interval in the left-right direction. More specifically, they are symmetrical to each other with respect to radioactive waste to be cut (used control rod 3 is illustrated in FIGS. 7A and 8A) installed in the main frame 15 in a vertical posture. Two guide members 41 are disposed at the respective positions. As shown in FIGS. 7B and 8B, the two guide members 41 each have a substantially U-shaped vertical cross-sectional shape, and a portion of the band saw 30 located between the two main pulleys 34. It is installed so that each may be pinched.

  Further, as shown in FIG. 9, the cutting direction switching mechanism 40 includes a guide rail member 43 formed in a substantially 90 ° arc shape, a support member 44 that supports the guide rail member 43, and a relative rotation to the support member 44. And a fluid pressure cylinder 42 mounted movably. The end 41a opposite to the U-shaped groove opening end of the guide member 41 is guided by the guide rail member 43, and is 90 ° between the upper end position in FIG. 9A and the lower end position in FIG. 9B. It is configured to be movable along the arc trajectory. The support member 44 is detachably attached to the band saw mounting base 31 (see FIGS. 7 and 8), and supports the guide rail member 43 and the guide member 41. The end 41 a of the guide member 41 is connected to the tip of the rod of the fluid pressure cylinder 42.

  Then, the cutting direction switching mechanism 40 moves the end 41a of the guide member 41 along the guide rail member 43 on a 90 ° arcuate track when the rod of the fluid pressure cylinder 42 advances and retreats, so that the guide member 41 is configured to rotate 90 ° about the center C0 of the band saw 30 as an axis. Thereby, the direction (cutting direction) of the band saw 30 guided by the guide member 41 is switched between the vertical direction (vertical direction) and the horizontal direction (horizontal direction) without shifting the position of the center C0 of the band saw 30. Is possible.

  As shown in FIG. 7, the radioactive waste (used control rod 3) is disposed between the two guide members 41 when the radioactive waste is cut. 7A and 7B, a portion of the band saw 30 located between the two main pulleys 34 is directed in the vertical direction by the two guide members 41, and the blade portion of the band saw 30 In the state where 30a faces downward, the radioactive waste can be cut in the vertical direction by moving the band saw 30 downward together with the lifting base 21 by the vertical drive mechanism 12.

  On the other hand, from the state of FIG. 7, when the two guide members 41 are driven to rotate 90 ° so that the U-shaped grooves are directed forward by the fluid pressure cylinder 42, as shown in FIG. The portion located between the two main pulleys 34 is directed laterally by the two guide members 41 so that the blade portion 30a of the band saw 30 faces forward. In this state, the radioactive waste can be cut in the horizontal direction by moving the band saw 30 together with the band saw mounting base 31 horizontally by the horizontal drive mechanism 13.

  Next, a configuration for fixing the radioactive waste carried into the main frame 15 will be described.

  As shown in FIGS. 1 and 2, on the inner side of the main frame 15, there are a first mounting frame 50 extending in the vertical direction at the center of the inner space, and two extending in the vertical direction around the first mounting frame 50. A second mounting frame 51 is provided. A plurality of main clamp devices 52 are attached to the first attachment frame 50 at intervals in the vertical direction. In addition, the second mounting frame 51 has a plurality of auxiliary clamp devices 53 for fixing a long radioactive waste in a vertical posture in cooperation with the plurality of main clamp devices 52, with an interval in the vertical direction. It is attached.

  As shown in FIG. 1, a fixing member 59 is swingably provided at the upper end portion of the main frame 15. The fixing member 59 is configured to press and fix the upper end of the first mounting frame 50 by being driven to swing by appropriate driving means such as a fluid pressure cylinder or a motor. Accordingly, the posture (vertical posture) of the radioactive waste in a state where the radioactive waste is fixed by the main clamp device 52 and the auxiliary clamp device 53 after the long radioactive waste is carried into the main frame 15. More stable.

  Moreover, in the cutting device 1 of this embodiment, the band saw 30 is employ | adopted as a cutting means to cut | disconnect radioactive waste. Since the band saw 30 has a small cutting width and a small cutting amount per blade, the cutting reaction force is small. Therefore, radioactive waste can be reliably fixed even with a small clamping force, and the clamping devices 52 and 53 can be miniaturized.

  By the way, the cutting device 1 of the present embodiment cuts two types of radioactive wastes having different shapes, such as a used control rod 3 (see FIG. 3) and a spent fuel channel box 4 (see FIG. 4). And when cutting | disconnecting these two types of radioactive waste, the clamp apparatuses 52 and 53 suitable for both are used, respectively.

  FIG. 10 is a horizontal sectional view of the periphery of the clamping device when the used control rod 3 is cut. As shown in FIG. 10, when the used control rod 3 including the cross-sectional main body 3a is cut, the first attachment frame 50a to which the main clamp device 52a is attached and the auxiliary clamp device 53a are respectively provided. Two attached second attachment frames 51a are used. The main clamp device 52a has a fixed arm 54 that is rotatable with respect to the first mounting frame 50a, and is fixed at a fixed position indicated by a solid line in FIG. 10 and a two-dot chain line in FIG. The fixed arm 54 is configured to rotate between the open position shown. The auxiliary clamp device 53a is a fluid pressure cylinder in which a pair of gripping portions 55 are rotatably attached to the tips of the rods.

  With this configuration, the used control rod 3 carried into the main frame 15 is fixed as follows. That is, in each of the main clamp devices 52a attached to the first attachment frame 50a, the fixed arm 54 is rotated from the open position to the fixed position, and the two cross-shaped used control rods 3 (main body 3a) are rotated. Grip each piece of plate. Further, in each of the auxiliary clamp devices 53a attached to the two second attachment frames 51a, the rod is advanced, and the tip of the remaining two plate pieces is moved by the grip portion 55 provided at the tip of the rod. Hold it.

  As shown in FIGS. 1 and 2, in the lower space in the main frame 15, when the speed limiter 3b at the lower end of the used control rod 3 is cut in the lateral direction and separated, this speed limiter is used. A fluid pressure cylinder 60 for fixing the portion 3b is provided. Further, an elevating mechanism 61 including a driving unit such as a cylinder for adjusting a cutting position (cutting height) at the time of the transverse cutting is also provided.

  FIG. 11 is a horizontal sectional view of the periphery of the clamping device when the spent fuel channel box 4 is cut. As shown in FIG. 11, when cutting the rectangular tubular spent fuel channel box 4, the first attachment with the main clamp device 52 b attached, which is different from the case of cutting the used control rod 3. Two second attachment frames 51b to which the frame 50b and the auxiliary clamp device 53b are attached are used. The main clamp device 52b includes a receiving member 56 that has a V-shaped groove 57 cut at a right angle and is fixed to the first mounting frame 50b. The auxiliary clamp device 53b is a fluid pressure cylinder in which a flat pressing portion 58 is attached to the tip of the rod.

  With this configuration, the spent fuel channel box 4 carried into the main frame 15 is fixed as follows. That is, the two surfaces of the rectangular tubular spent fuel channel box 4 are brought into contact with two inner surfaces of the V-shaped groove 57 formed in the receiving member 56 of the main clamp device 52b, which are orthogonal to each other. In this state, the rod is advanced in each of the auxiliary clamp devices 53b attached to the two second attachment frames 51b, and the remaining portion of the spent fuel channel box 4 is retained by the pressing portion 58 provided at the tip of the rod. Press two sides.

  In this way, depending on which one of the used control rod 3 and the used fuel channel box 4 is to be cut, by selecting the mounting frames 50 and 51 to which the clamping device corresponding to the cutting target is attached, the shapes are different. Each radioactive waste can be securely fixed. In the above description, the clamping devices 52 and 53 are exchanged together with the mounting frames 50 and 51. However, the mounting frames 50 and 51 are common, and the clamping devices 52 and 53 attached to the mounting frames 50 and 51 are common. May be replaced according to the object to be cut.

  Further, as shown in FIG. 11, when the spent fuel channel box 4 is cut, in addition to the main clamp device 52b and the auxiliary clamp device 53b described above, a core type that stretches the spent fuel channel box 4 from the inside. The clamping device 62 is used together.

  12 is a side view of the core type clamping device 62, and FIG. 13 is a horizontal sectional view taken along line XIII-XIII in FIG. As shown in FIGS. 12 and 13, the clamp device 62 includes a clamp body 63 having a square cylinder outer shape that is slightly smaller than the spent fuel channel box 4, and a clamp cylinder 64 built in the clamp body 63. And a clamp head 65 connected to the piston 67 of the clamp cylinder 64.

  Two clamp cylinders 64 are provided on the upper and lower sides in the clamp body 63. Each clamp cylinder 64 has a cylinder hole 66 formed in the clamp body 63 and two pistons 67 slidably disposed in the cylinder hole 66. The cylinder space 66 is partitioned by two pistons 67 to form three cylinder chambers 68a, 68b, 68c. These three cylinder chambers 68a, 68b, and 68c communicate with drill holes (not shown) formed in the clamp body 63 as fluid supply paths, respectively, and at the end of each drill hole, respectively. An external high-pressure hose (not shown) for supplying high-pressure fluid is connected.

  In addition, two clamp heads 65 are connected to the two pistons 67 by screws 69, respectively. Then, each clamp cylinder 64 is supplied with a fluid such as high-pressure water or high-pressure air through a drill hole formed in the clamp body 63, whereby the two clamp heads 65 connected to the two pistons 67 are provided. Each is driven forward and backward. At this time, the two clamp heads 65 press the two corners at the diagonal positions of the spent fuel channel box 4 so as to stretch from the inside.

  A rod connecting portion 66 is provided at the upper end of the clamp body 63, and a rod 67 for raising and lowering the clamp device 62 is connected to the rod connecting portion. The clamp device 62 is intermittently driven downward via a rod 67 by an appropriate driving means (not shown) according to the longitudinal cutting operation of the spent fuel channel box 4 by the band saw 30.

  Next, the radioactive waste cutting method using the cutting apparatus 1 described above will be described. FIG. 14 is a diagram illustrating a cutting process of the used control rod 3, and FIG. 15 is a diagram illustrating a cutting process of the spent fuel channel box 4. As shown in FIGS. 14 and 15, the cutting device 1 is installed in a pool 100. And in this pool 100 (underwater), the radioactive waste is carried in and carried out to the cutting device 1. 14 and 15, the cutting device 1 is installed on the bottom surface of the pool 100, but depending on the water depth of the pool 100, a bridge (not shown) is provided in the pool 100, and A cutting device 1 may be installed.

(Cutting process of used control rods)
When the long used control rod 3 shown in FIG. 3 is cut by the cutting device 1, first, as shown in FIG. 14A, the vertical control rod 22 and the drive unit 23 (see FIG. 2) are included. The directional drive mechanism 12 lowers the elevating base 21 to the lower end position, and the lateral drive mechanism 13 including the fluid pressure cylinder 33 moves the band saw mounting base 31 to which the band saw 30 is attached to the retracted position (leftward in FIG. 14). Move back to the movement limit position). In this state, the used control rod 3 suspended by a wire or the like is carried into the main frame 15 of the cutting apparatus 1 as indicated by an arrow.

  At this time, one or both of the band saw 30 and the used control rod 3 are driven by the vertical drive mechanism 12 that drives the band saw 30 in the vertical direction and the lifting mechanism 61 that drives the used control rod 3 in the vertical direction. By adjusting the vertical position, the vertical positions of the band saw 30 and the boundary portion between the main body 3a and the speed limiter 3b of the used control rod 3 are matched. Then, the fixing arm 54 (see FIG. 10 for details) of the main clamp device 52a attached to the first attachment frame 50a is set to the fixed position, and the rod of the auxiliary clamp device 53a attached to the second attachment frame 51a is advanced. Further, the grip part 55 at the tip of the rod is gripped. Furthermore, the upper end of the first mounting frame 50a is pressed by a fixing member 59 (see FIG. 1) to fix the first mounting frame 50a. As a result, the used control rod 3 is securely fixed in a vertical posture in which the length direction is the vertical direction. Further, the speed limiter 3 b of the used control rod 3 is fixed by the fluid pressure cylinder 60.

  Further, the two guide members 41 having a substantially U-shaped cross section arranged so as to sandwich the band saw 30 are rotated by 90 ° in the same direction by the fluid pressure cylinders 42, respectively. 41, the blade portion 30a of the band saw 30 is directed forward, and the cutting direction is switched from the vertical direction to the horizontal direction.

  In this state, as shown in FIG. 14B, the band saw 30 is moved forward by the lateral drive mechanism 13 while the band saw 30 is driven to travel by the band saw drive motor 36, and the band saw 30 oriented in the lateral direction. The used control rod 3 is cut at the boundary portion between the main body 3a and the speed limiter 3b by the blade 30a to separate the speed limiter 3b from the main body 3a (lateral cutting step). In addition, after the used control rod 3 is cut in the lateral direction in this way, the upper body portion 3a is fixed by the main clamp device 52a and the auxiliary clamp device 53a, and the speed limiter portion 3b at the lower end portion. Is fixed by the fluid pressure cylinder 60.

  Next, after the rod of the auxiliary clamp device 53a attached to the second attachment frame 51a is once retracted, the vertical drive mechanism 12 is used to bring the lifting base 21 to the upper end position as shown in FIG. 14 (c). Raise. Thereafter, the band saw 30 is moved backward by the lateral drive mechanism 13, and the position of the band saw 30 in the lateral direction is changed to the position of the cross-shaped central portion 3 c of the main body 3 a of the used control rod 3 (the position of C 1 indicated by a one-dot chain line) Adjust to match. Then, the rod of the auxiliary clamp device 53a is advanced again to be gripped by the grip portion 55 at the tip of the rod, and the main body portion 3a is fixed again.

  Further, the two guide members 41 having a substantially U-shaped cross section arranged so as to sandwich the band saw 30 are rotated by 90 ° in the same direction by the fluid pressure cylinder 42, respectively, as shown in FIG. The blade part 30a is directed downward, and the cutting direction is switched from the horizontal direction to the vertical direction.

  In this state, as shown in FIG. 14 (d), the band saw 30 in the traveling state is lowered at a predetermined speed by the longitudinal drive mechanism 12, and the main body 3a is cut by the blade portion 30a of the band saw 30 oriented in the longitudinal direction. The cross-shaped central portion 3c is cut along the length direction and separated into two L-shaped pieces 5a and 5b (vertical cutting step).

  Thus, after separating the main body 3a into the two L-shaped pieces 5a and 5b, the separated radioactive waste is put into the main frame 15 in the order of the L-shaped piece 5a, the L-shaped piece 5b, and the speed limiter 3b. Take out from. The two L-shaped pieces 5a and 5b are accommodated in a storage box 2 shown in FIGS. 5 and 6, and the speed limiter 3b is accommodated in a separate storage box (not shown).

(Cutting process of spent fuel channel box)
When the long rectangular tube-shaped spent fuel channel box 4 shown in FIG. 4 is cut by the cutting device 1, first, as shown in FIG. 15 (a), the lateral drive including the fluid pressure cylinder 33 is performed. The mechanism 13 moves the band saw mounting base 31 to which the band saw 30 is mounted to the retracted position. In this state, the spent fuel channel box 4 from which the upper clip 4 a and the spacer 4 b have been removed in advance is suspended by a wire or the like by a method not shown, and is carried into the main frame 15 of the cutting device 1.

  Then, the rod of the auxiliary clamp device 53b attached to the second attachment frame 51 is advanced to be used for the receiving member 56 (see FIG. 10 for details) of the main clamp device 52b attached to the first attachment frame 50b. The spent fuel channel box 4 is pressed and securely fixed in a vertical posture in which the length direction is the vertical direction.

  Further, by rotating the two guide members 41 having a substantially U-shaped cross section arranged so as to sandwich the band saw 30 by the fluid pressure cylinder 42, the blade portion 30a of the band saw 30 is moved downward as shown in FIG. The cutting direction is switched to the vertical direction.

  Next, as shown in FIG. 15 (b), the band saw 30 is advanced forward by the lateral drive mechanism 13, and the lateral position of the band saw 30 is a diagonal line connecting the two corners of the spent fuel channel box 4. To be matched with the position (the position of C2 indicated by the alternate long and short dash line).

  In this state, as shown in FIG. 15C, while the band saw 30 is driven to travel by the band saw drive motor 36, the band saw 30 is lowered by the vertical drive mechanism 12, and the band saw 30 oriented in the vertical direction (downward). The blade portion 30a cuts the two corner portions of the spent fuel channel box 4 at diagonal positions along the length direction and separates them into two L-shaped pieces 5a and 5b (vertical cutting step).

  In this longitudinal cutting process, the core-type clamp device 62 is inserted into the spent fuel channel box 4 from above, and the clamp head 65 of the clamp device 62 stretches the channel box 4 from the inside. In the state where it is, longitudinal cutting by the band saw 30 is performed. More specifically, when the band saw 30 cuts the channel box 4 by a predetermined length, the lowering (cutting) of the band saw 30 is temporarily stopped, and the core-type clamp device 62 is placed immediately above the band saw 30. Then, it is lowered to a position where it does not interfere with the band saw 30. In this position, the longitudinal cutting by the band saw 30 is resumed in a state where the core-type clamping device 62 is stretching the channel box 4 from the inside. Thereafter, the spent fuel channel box 4 is extended over the entire length while intermittently performing cutting of a predetermined length by the band saw 30 and lowering (height position change) of the core clamp device 62 following the lowering of the band saw 30. Cut vertically.

  In this way, whenever the band saw 30 cuts a predetermined length, the core-type clamp device 62 is also intermittently lowered in accordance with the lowering of the band saw 30 to change the position to be stretched from the inside, Longitudinal cutting by the band saw 30 can be performed more stably.

  After separating the spent fuel channel box 4 into the two L-shaped pieces 5a and 5b as described above, the core-type clamping device 62 is retracted upward, and then the two L-shaped pieces 5a and 5b. Are taken out from the main frame 15 in order. Then, these two L-shaped pieces 5a and 5b are accommodated in the storage box 2 shown in FIGS.

  According to the radioactive waste cutting apparatus 1 and the radioactive waste cutting method of the present embodiment described above, the following effects can be obtained.

  The cutting direction switching mechanism 40 switches the cutting direction of the band saw 30 (the direction of the blade portion 30a in the portion for cutting the radioactive waste) to the vertical direction or the horizontal direction, and then the vertical driving mechanism 12 or the horizontal driving mechanism 13 By moving the band saw 30 in the cutting direction (longitudinal direction or lateral direction), the radioactive waste can be cut in the longitudinal direction and the lateral direction, respectively. As described above, both the vertical cutting and the horizontal cutting can be performed with one band saw 30, so that the configuration of the apparatus is simplified and maintenance work such as replacement of the band saw 30 is simplified. Further, when the cutting unit 11 is maintained, the cutting unit 11 can be moved to the upper end position by the vertical driving mechanism 12, so that maintenance work such as replacement of the band saw 30 becomes very easy.

  Compared to other cutting means, the band saw 30 can easily cut radioactive wastes of various shapes and thickness (for example, the thick cross-shaped central portion 3c of the used control rod 3). Can do. In addition, since the cutting width is small and the cutting amount per blade is small, the cutting reaction force is small. Therefore, radioactive waste can be reliably fixed with a small clamping force. Further, in mechanical cutting using the band saw 30, there is no gas generation in plasma arc cutting or laser cutting, no partition is required, and work such as replacement of an off-gas filter does not occur. Further, there is no generation of sludge-like secondary waste in cutting with high-pressure water (water jet) mixed with an abrasive. Since the cutting device 1 is compact, installation work is facilitated, and an effect of reducing running cost by simplifying the maintenance work can be obtained.

  The switching direction switching mechanism 40 is a simple operation in which the guide member 41 that guides the band saw 30 is rotated by the fluid pressure cylinder 42, and the cutting direction of the band saw 30 is easily changed between the vertical direction and the horizontal direction. Can be switched. Further, since the two guide members 41 are arranged at symmetrical positions with respect to the radioactive waste, the portion of the band saw 30 that directly cuts the radioactive waste is guided by the two guide members 41 from both sides. Thus, radioactive waste can be cut stably.

  The embodiment of the present invention has been described above with an example, but the form to which the present invention can be applied is not limited to the above-described embodiment.

  For example, in the above embodiment, the transverse cutting is performed only when the main body 3a and the speed limiter 3b of the used control rod 3 are separated, but the main body 3a of the long used control rod 3 In order to shorten the length of the spent fuel channel box 4, transverse cutting may be performed.

  Moreover, in the said embodiment, although the radioactive waste (used control rod 3) is cut | disconnected in the vertical direction after cut | disconnecting to a horizontal direction, you may cut | disconnect in a horizontal direction after cut | disconnecting to a vertical direction.

  Moreover, in the said embodiment, although the band saw 30 is moved to the vertical direction and the horizontal direction with respect to radioactive waste by the vertical direction drive mechanism 12 and the horizontal direction drive mechanism 13, on the contrary, the direction of radioactive waste The radioactive waste can also be cut with the band saw 30 by moving it in the vertical and horizontal directions with respect to the band saw 30.

  Furthermore, the band saw 30 can be moved with respect to the radioactive waste in the vertical direction and the horizontal direction by the vertical direction drive mechanism 12 and the horizontal direction drive mechanism 13, respectively. Further, the cutting direction of the band saw 30 by the cutting direction switching mechanism 40 Can be switched between the vertical direction and the horizontal direction, so that various kinds of radioactive waste other than the used control rod 3 having a cross-sectional shape and the spent fuel channel box 4 having a square cylindrical shape can be used. The volume can be reduced by cutting at various positions.

It is a perspective view of a radioactive waste cutting device concerning an embodiment of the present invention. It is a side view of the cutting device of FIG. It is a perspective view of a used control rod. It is a perspective view of a spent fuel channel box. It is a perspective view of the storage box in which the L-shaped piece was accommodated. It is the figure which looked at the storage box of FIG. 5 from upper direction. (A) is a top view of a cutting unit (longitudinal direction in the cutting direction), and (b) is a sectional view taken along line VIIa-VIIa in (a). (A) is a top view of a cutting | disconnection unit (cutting direction horizontal direction), (b) is the VIIIa-VIIIa sectional view taken on the line of (a). It is a figure which shows a cutting | disconnection direction switching mechanism, (a) shows the state in which the cutting direction of a band saw is a vertical direction, (b) shows the state in which the cutting direction of a band saw is a horizontal direction, respectively. It is a horizontal sectional view of a clamp device peripheral part in the case of cutting a used control rod. It is a horizontal sectional view of a clamp device peripheral part in the case of cutting a spent fuel channel box. It is a side view of a core type clamping device. FIG. 13 is a horizontal view taken along line XIII-XIII of the clamp device of FIG. 12. It is a figure which shows the cutting process of a used control rod. It is a figure which shows the cutting process of a spent fuel channel box.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radioactive waste cutting device 3 Used control rod 3a Main part 3b Speed limiter part 4 Fuel channel box 11 Cutting unit 12 Longitudinal drive mechanism 13 Lateral drive mechanism 30 Band saw 40 Cutting direction switching mechanism 41 Guide member 42 Fluid pressure cylinder

Claims (6)

A radioactive waste cutting apparatus for cutting radioactive waste elongated in one direction in water,
Cutting means including a band saw;
Longitudinal drive means for moving one of the band saw and the radioactive waste relative to the other in the longitudinal direction, which is the length direction of the radioactive waste,
Lateral drive means for moving one of the band saw and the radioactive waste relative to the other in a lateral direction perpendicular to the longitudinal direction of the radioactive waste;
Cutting direction switching means for switching the cutting direction of the band saw between the vertical direction and the horizontal direction;
A radioactive waste cutting apparatus comprising: The cutting direction switching means is
A guide member for guiding the band saw;
A radioactive waste cutting apparatus comprising: a rotation driving unit that rotates the guide member to change the direction of the band saw.   The radioactive waste cutting apparatus according to claim 2, wherein the two guide members are respectively arranged at positions symmetrical to each other with respect to the radioactive waste to be cut. A radioactive waste cutting method for cutting radioactive waste that is long in one direction in water,
A band saw is cut in a longitudinal direction, which is a length direction of the radioactive waste, and then one of the band saw and the radioactive waste is moved relative to the other in the longitudinal direction to thereby form the radioactive waste. A longitudinal cutting step of cutting in the longitudinal direction;
The cutting direction of the band saw is oriented in a lateral direction orthogonal to the longitudinal direction, and then one of the band saw and the radioactive waste is moved relative to the other in the lateral direction, and the radioactive waste is moved to the lateral direction. A transverse cutting process to cut in the direction;
The radioactive waste cutting method characterized by comprising. The radioactive waste is a used control rod having a main body having a cross-shaped cross section parallel to the lateral direction and a speed limiter provided at one end in the length direction of the main body.
In the longitudinal cutting step, the cross-shaped central portion of the main body of the used control rod is cut along its length direction, and the main body is separated into two L-shaped pieces,
5. The radioactive waste cutting method according to claim 4, wherein, in the transverse cutting step, the main body portion and the speed limiter portion of the used control rod are cut and separated from each other. The radioactive waste is a rectangular cylinder-shaped spent fuel channel box;
In the longitudinal cutting step, a corner portion of the spent fuel channel box is cut along its length direction, and the spent fuel channel box is cut into two L-shaped pieces or four long plate-like pieces. The radioactive waste cutting method according to claim 4, wherein the radioactive waste is cut.

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