JP4500224B2 - Volume reduction system and method for used control rod - Google Patents

Description

  The present invention relates to a technique for reducing the volume of a used control rod (hereinafter referred to as CR) taken out from a nuclear power plant reactor.

  The control rod 20 (see FIG. 3) used for adjusting the output in the nuclear power plant reactor is appropriately replaced with a new control rod as a consumable part after a predetermined period of use. And since the taken-out used control rod 20 is radioactively contaminated, it is safely disposed of by a known method. By the way, since the cross section of the control rod 20 has a cross shape as shown in FIG. 4, it becomes bulky when the number of used control rods is gathered, and the container for containing radioactive pollutants is immediately filled. There is a problem.

Accordingly, the used control rod 20 is appropriately divided in order to reduce the occupied volume (hereinafter referred to as volume reduction). This division work is performed by remote control by a thermal cutting unit adopting a plasma method or the like in water such as a pool in order to reduce the exposure of the worker.
The conventional volume reduction method for the used control rod 20 has been performed as follows using one thermal cutting means.

First, while rotating the control rod 20 shown in FIG. 3 by 90 degrees, the portions where the velocity limit portion 25 is coupled to the blade portion 23 at four locations (P _{1 to} P ₄ portions) are thermally cut one by one. Then, the velocity limit unit 25 is separated from the main body of the control rod 20. Subsequently, the tie rod portion 22 connecting the four blade portions 23 in a cross shape is thermally cut into a cut piece having an L-shaped cross section in which the two blades are combined. If the peaks and valleys of this L-shaped cut piece are stacked and stored, the used control rod 20 can be reduced in volume and stored. Patent Document 1 discloses a technique for reducing the volume of a spent fuel channel box as a known literature invention.
JP 62-174696 A (page 3-4, FIG. 8)

In the conventional method for reducing the volume of the control rod, since the tie rod portion 22 is cut after the velocity limit portion 25 is cut by one thermal cutting means as described above, either the velocity limit portion 25 or the tie rod portion 22 is cut. When the cutting operation is being performed, the subsequent operation of the control rod 20 is in a completely waiting state, resulting in a problem of low work efficiency.
Further, since the thermal limit method is used for the cutting of the velocity limit unit 25, a large amount of fine particles are generated in the pool, and a load is applied to the filter for collecting the fine particles. It was.

  The present invention solves the above-described conventional problems, and provides a technique for efficiently reducing the volume of used control rods and reducing the fine particles generated by the volume reduction. Objective.

In order to achieve the above object, the present invention provides a system for reducing the volume of spent control rods taken from a nuclear power plant reactor in a pool filled with water. A first cutting part that cuts into an end cutting bar, and a second cutting part that is arranged at a position different from the first cutting part and cuts the end cutting bar along the longitudinal direction into a longitudinal cutting piece A rack for placing the control rod and / or the end cutting rod, a storage container for storing the vertical cutting piece, the control rod, the end cutting rod or the vertical cutting piece, A cutting unit, a second cutting unit, a rack, and a transport unit capable of transporting each other with respect to the storage container, wherein the first cutting unit performs the cutting by shearing to move the cutter. The second cutting part is a space isolated inside the pool. In being adapted to perform the cutting, the period until the cutting of the second cutting portion is completed, the transport unit conveys the control rod to said first cutting portion, said first cutting portion After the cutting is performed, the cut end cutting bar is transported to the rack .

With this configuration, the cutting of the end portion of the control rod and the cutting along the longitudinal direction can be simultaneously performed in parallel as separate steps in the first cutting portion and the second cutting portion, respectively. Furthermore, the end cutting bar that has completed the cutting process in the first cutting unit can be made to stand by in the rack even when the second cutting unit is working. The process can be continued. Thereby, the volume reduction operation | work of many control rods can be implemented efficiently in a short time.
In addition, since the first cutting part is constituted by a blade, it is possible to reduce the amount of fine particles generated during the horizontal cutting of the control rod. Furthermore, since the second cut portion is surrounded by the partition walls, it is possible to suppress the generated fine particles from diffusing to the outside.

  According to the present invention, the cutting of the end portion of the control rod and the longitudinal cutting can be performed in separate steps, so that the volume reduction operation of the used control rod can be efficiently performed, and this It is possible to provide a technique for reducing fine particles generated during volume reduction work.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. As shown in FIG. 1, a volume reduction system S (hereinafter simply referred to as volume reduction system S) for a used control rod includes a CR transport unit (transport unit) 30, a VL cutting unit (first cutting unit) 40, TR It comprises a cutting unit (second cutting unit) 50, a rack 60, a storage container 70, and a system controller (not shown). In addition, such a volume reduction system S is arrange | positioned in the pool L filled with water so that it can carry out by remote operation in water for a worker's exposure reduction.

(Description of control rod 20)
As shown in FIG. 3, the control rod 20 (hereinafter may be referred to as CR: Control Rod) includes a handle portion 21 and a tie rod portion 22 (hereinafter may be referred to as TR (Tie Rod)). It is comprised from the blade part 23, the connection part 24, and the velocity limit part 25 (Hereafter, it may describe as VL (Velocity limit).). FIG. 3 omits the central portion of the control rod 20 and shows only both end portions in the longitudinal direction, and clearly shows a cross-sectional structure that is not normally exposed. In order to distinguish the state where the control rod 20 is cut in each process of the volume reduction system S in the following, the state where the velocity limit portion 25 is cut is referred to as a VL cutting rod (end cutting rod) 20b, and further a tie rod. The state in which the portion 22 is cut is shown as a TR cut piece (longitudinal cut piece) 20c, and the state where no part is cut is shown as a control rod 20a. It will be described as a control rod 20.

The handle portion 21 is a portion that is gripped by the heavy machinery when the control rod 20 is attached to, detached from, or transferred to the core using the heavy machinery.
As shown in FIG. 4, the tie rod (TL) portion 22 fixes one end portion of the blade portion 23 so that the center of the cross-shaped cross section formed by the four blade portions 23 described later is formed. To do.
The blade portion 23 is inserted into and removed from a gap in which a plurality of channel boxes (not shown) containing nuclear fuel are arranged to control nuclear fuel fission. A large number of neutron absorbing rods 26, 26... That absorb neutrons generated by fission are arranged in the blade portion 23 along the longitudinal direction of the control rod 20.

The connecting portion 24 is provided at a longitudinal end portion of the control rod 20, and connects the control rod 20 and a control rod drive mechanism (not shown) of the nuclear reactor.
A velocity limit (VL) portion 25 is also provided at the end of the control rod 20 in the longitudinal direction. Even if the velocity limit (VL) unit 25 is dropped while the control rod 20 is being transferred, the velocity limit (VL) unit 25 receives the resistance of water and suppresses the drop speed of the control rod 20. The function to perform is demonstrated. In this way, the velocity limit unit 25 plays a role of preventing damage to the bottom surface of the pool L and the inside of the nuclear reactor even when the control rod 20 falls.

(Description of CR transport unit 30)
The CR transport unit (transport unit) 30 includes a moving mechanism unit 31, a telescopic unit 32, a gripping unit 33, and a rotation mechanism unit 34. And CR conveyance part 30 conveys control rod 20 between VL cutting unit 40, TR cutting unit 50, rack 60, and storage container 70 as shown in each process of ad of Drawing 1. The position of the control rod 20 can be gripped so as to be displaced in the vertical direction. The CR transport unit 30 is remotely operated by a system control device (not shown) while confirming the positional relationship between the gripping unit 33 and the control rod 20 by visual observation or an underwater camera.

The moving mechanism unit 31 moves in the horizontal direction on the water surface of the pool L filled with water, and moves the CR transport unit 30 directly above the VL cutting unit 40, the TR cutting unit 50, the rack 60, and the storage container 70. It is to be positioned.
The expansion / contraction part 32 moves the grip part 33 provided at the tip thereof in the vertical direction by expanding and contracting itself. As a result, the control rod 20 is taken into and out of each device (rack 60, VL cutting unit 40, TR cutting unit 50, storage container 70) provided in the pool L.

The grip portion 33 is for gripping and releasing the control rod 20. As shown in FIG. 1, the grip portion 33 is composed of two independent hydraulic cylinders. By operating this, the two portions of the two blade portions 23 adjacent to the control rod 20 are sandwiched. To grip. Further, these two hydraulic cylinders can be operated independently to hold the control rod 20 at any one of the locations.
The rotation mechanism unit 34 is configured to arbitrarily change the angle of the gripping unit 33 by rotating the control rod 20 so that the tie rod unit 22 (FIG. 4) is the central axis.

(Description of VL cutting unit 40)
The VL cutting unit (first cutting unit) 40 includes a first fixing unit 41, a first cutting unit 42, and a VL storage container 43. Then, the VL cutting unit 40 cuts the four connecting portions (P _{1 to} P _{4 in} FIG. 3) where the velocity limit portion 25 is connected to the blade portion 23, and connects the velocity limit portion 25 and the connecting portion 24. The terminal part to include is cut off from the main body of the control rod 20a.

The first fixing portion 41 freely achieves fixing or releasing the control rod 20a with respect to the VL cutting unit 40.
As shown in FIG. 5, the first cutting means 42 is composed of a fixed blade 42a and a moving blade (blade) 42b. The first cutting means 42 is moved forward by a hydraulic cylinder or the like to connect the velocity limit portion 25 and the blade portion 23. it is intended to shear the (P ₁ ~P _4). Then, as shown in FIG. 5 (a) (b), when cutting the one position of these coupling portions (P ₁ ~P _4), as shown in FIG. 5 (c) (d), the fixed blade 42a While the movable blade 42b moves backward, the control mechanism 20 (see FIG. 1) rotates the control rod 20a by 90 °, and the adjacent coupling portion (P _{2 in the} drawing) is positioned between the blades. By repeating these operations, the coupling portions (P _{1 to} P ₄ ) are sheared and the velocity limit portion 25 is separated from the main body of the control rod 20a as shown in FIGS. become.

When such a moving blade 42b moves forward or backward, a limit switch (not shown) provided on the fixed blade 42a side or the moving blade 42b side is activated, and the coupling portions (P _{1 to} P ₄ ) are operated. It is detected whether the cutting has been completed.
According to the method of separating the velocity limit part 25 from the main body of the control rod 20a by such a shearing method, there is a feature that the generation amount of chips and dross generated at the time of cutting can be reduced as compared with the thermal cutting method. . Therefore, the VL cutting unit 40 is not particularly required to be provided with a filter or the like for collecting such chips or dross, or a partition wall for preventing diffusion into the pool L.

  The VL storage container 43 receives the velocity limit part 25 separated from the main body of the control rod 20 a by the first cutting means 42. In addition, chips and the like generated during shearing are also captured in the VL storage container 43 by free fall. When the velocity limit part 25 is cut off and dropped, a proximity sensor (not shown) provided in the VL storage container 43 detects the dropped velocity limit part 25 and recognizes that the cutting is finished.

(Description of TR cutting unit 50)
The TR cutting unit (second cutting unit) 50 includes a second fixing unit 51, a thermal cutting unit 52, a partition wall 53, a purification unit 54, and a gas recovery port 55. Then, the TR cutting unit 50 cuts the VL cutting rod 20b from which the velocity limit portion 25 has been cut along the longitudinal direction as shown in the two-dot chain line in FIG. Two sets of TR cut pieces 20c having an L-shaped cross section are formed.
In addition, the work process in this TR cutting unit 50 takes time compared with the work process of the VL cutting unit 40. Therefore, a plurality of TR cutting units 50 that are not arranged in FIG. 1 may be arranged in the pool L so that the vertical cutting processing of the plurality of VL cutting bars 20b can be performed simultaneously in parallel.

  The 2nd fixing | fixed part 51 fixes the VL cutting rod 20b mounted in the state standing upright on the mounting base 56 so that it may not move. As shown in FIG. 4, the second fixing portion 51 includes a plurality of (two in the drawing) gripping means 51 a and 51 b that grip the blade portions 23 and 23, respectively.

  The thermal cutting means 52 is a means for thermally cutting, such as a plasma cutter, and as shown in FIG. 6 (b), guides to a rail 57 arranged along the longitudinal direction of the VL cutting rod 20b. It moves up and down. As shown in FIGS. 6 (d) and 6 (e), the tip of the thermal cutting means 52 is close to the tie rod portion 22 and moves up and down to cut the tie rod portion 22, so that the VL cutting rod 20b Are separated into two L-shaped TR cut pieces 20c, 20c.

The partition wall 53 serves to prevent the highly radioactive fine particles (dross) from diffusing throughout the pool L by being generated in the water by using the thermal cutting means 52. That is, the partition wall 53 isolates the internal space of the TR cutting unit 50 that cuts the VL cutting rod 20b from the pool L in a sealed state.
The partition wall 53 is provided with an opening / closing door 58. When the opening / closing door 58 is closed, the inside of the TR cutting unit 50 is hermetically sealed as shown in FIG. , Do not scatter in pool L.
On the other hand, the open / close door 58 is opened, and the VL cutting rod 20b transferred by the CR transport unit 30 is inserted upright on the mounting table 56 as shown in FIG. As shown in (c), the cut TR cut piece 20c is carried out. When the VL cutting rod 20b is placed on the mounting table 56, the CR transport unit 30 is retracted from the TR cutting unit 50 until the cutting is finished and the TR cutting piece 20c is unloaded. In this way, while the CR transport unit 30 is retracted, the open / close door 58 is closed and the TR cutting unit 50 is kept airtight as shown in FIG. 6B.

The purifying means 54 is provided in the partition wall 53 and removes fine particles floating inside the TR cutting unit 50 in a sealed state by the filter F by the suction force of the pump P, and discharges the purified water into the pool L. It is. Then, water corresponding to the discharged amount is sucked into the TR cutting unit 50 from the pool L through the suction port 59.
The flow rate of the pump P is determined by appropriately setting the pump operation time in consideration of the internal volume of the TR cutting unit 50 and the like. The operating status is monitored by a sequencer or software and recognized by the operator. In addition, the opening / closing door 58 is not opened to prevent the fine particles from diffusing into the pool L until the purification work inside the TR cutting unit 50 is finished by the purification means 54.
If the thermal cutting means 52 is a plasma cutting method or the like, the gas recovery means 55 recovers the gas used for this (Ar gas or the like) or the generated gas and exhausts it to a safe place with a fan f or the like or processes it. Is to do.

(Description of other components)
As shown in FIG. 2, the rack 60 has a plurality of storage sections 61, 61... For storing the control rods 20, and the control rods 20 a and VL are cut in a series of steps in the volume reduction operation of the control rods 20. This is the place where the rod 20b is placed. Then, the control rod 20 (20a, 20b) is taken in and out of the rack 60 by the operation of the CR transport unit 30 (see FIG. 1) and transported to the VL cutting unit 40 and the TR cutting unit 50.
Then, a unique address is assigned to the storage section 61, 61... Of the rack 60, the control rods 20 (20a, 20b) that are carried in are associated with each other, and managed by a storage device in the system control device described later. Has been. For this reason, information such as how many control rods 20 (20a, 20b) are placed in which storage section 61 of the rack 60 can be confirmed in a timely manner.

  The storage container 70 is a container for storing the TR cut piece 20c generated by dividing the used control rod 20a through a series of steps. These TR cut pieces 20c, 20c,... Are stored in the storage container 70 with the peaks and valleys having an L-shaped cross section overlapped, so that the volume (volume reduction) of the control rod 20a is reduced.

The system control device (not shown) executes operation management of all the devices constituting the volume reduction system S in cooperation with a sequencer and software. Specifically, the horizontal direction in the CR transport unit 30 Movement and vertical movement / gripping / opening operation of the gripping portion 33, holding / releasing of the first fixing portion 41 in the VL cutting unit 40, cutting operation of the first cutting means 42, opening / closing door 58 in the TR cutting unit 50 Open / close, hold / release the second fixing portion 51, cut the thermal cutting means 52, operate the pump P, manage inventory information of the control rods 20 (20a, 20b, 20c) in the rack 60 and the storage container 70, etc. To do.
Then, based on the position information output from sensors such as limit switches or encoders of these devices, the time information for operating the pump P, etc. Is to do.

(Description of operation)
Next, referring to FIG. 7 (refer to other drawings as appropriate), the operation of the volume reduction system S for used control rods will be described, and the volume reduction method for used control rods according to the present invention will also be described. To do.
First, as shown in step A of FIG. 2, the control rod 20a is transported from the rack 60 to the VL cutting unit 40 by the CR transport unit 30 (step S11, hereinafter “step” is omitted). Then, the velocity limit unit 25 is cut in the VL cutting unit 40 (S12).

  Next, depending on the work status of the TR cutting unit 50, it is determined whether the VL cutting bar 20b is to be continuously cut vertically or returned to the rack 60. Normally, however, the TR cutting unit 50 is not used in the first trial. It is in use. Therefore, as shown in Step C, the VL cutting rod 20b is transported from the VL cutting unit 40 to the TR cutting unit 50 by the CR transport unit 30 (S13).

  When the VL cutting rod 20b is transported to the TR cutting unit 50, the CR transport unit 30 opens the gripped VL cutting rod 20b and retracts from the TR cutting unit 50 (S14). Next, the open / close door 58 is closed and the inside of the TR cutting unit 50 is sealed, and the thermal cutting means 52 is operated to start cutting the tie rod portion 22 (S15). Thus, during the period until the cutting of the tie rod portion 22 ends (S15 to S20), the CR transport portion 30 is in a free state.

Therefore, as shown in A process and B process in FIG. 2, the CR transport unit 30 transports the control rod 20 a from the rack 60 to the VL cutting unit 40, and laterally cuts the velocity limit unit (terminal portion) 25. Is performed, and the operation of transporting and returning the VL cutting rod 20b back to the rack 60 is performed (S16 to S18).
After the CR transport unit 30 stores the VL cutting rod 20b in the rack 60, it is determined whether or not the work in the TR cutting unit 50 has been completed, and if the TR cutting is still being executed (S19: No), step Returning to S16, the A process and the B process are further repeated, and another control rod 20a is conveyed from the rack 60 to execute VL cutting.

  If TR cutting has been completed (S19: Yes), the CR transport unit 30 transports the TR cut piece 20c from the TR cutting unit 50 to the storage container 70 (S21). In this way, the operation flow from step S11 to step S22 is repeated until there is a command to end the volume reduction operation of the control rod 20a (step S22: Yes, No).

As described above, in the method for reducing the volume of the used control rod according to the present invention, the control rod 20a is moved from the rack 60 to the VL cutting unit (first cutting portion) 40, as shown in FIG. It includes a step of transporting and cutting the velocity limit part (terminal part) 25 into a VL cutting bar (end cutting bar) 20b, and then returning the VL cutting bar 20b from the VL cutting unit 40 to the rack 60. Yes.
Further, as shown in step D, the VL cutting rod 20b is transported from the rack 60 to the TR cutting unit (second cutting portion) 50, cut along the longitudinal direction, and turned into a TR cutting piece (vertical cutting piece) 20c. It also includes a stage to do.

For this reason, in parallel with the longitudinal cutting (TR cutting) work in the TR cutting unit 50, the terminal cutting (VL cutting) work by the VL cutting unit 40 can be performed simultaneously.
When the longitudinal cutting (TR cutting) work in the TR cutting unit 50 is completed, the process proceeds to step E, and the TR cutting piece 20c is transported from the TR cutting unit (second cutting unit) 50 to the storage container 70 and stored. Through the steps, a series of used control rod volume reduction operations are achieved.
In this series of work steps, the process in the TR cutting unit 50 takes a long time. However, if a plurality of TR cutting units 50 are installed to increase the processing capacity, the entire period can be further shortened. It is.

  Further, depending on the progress of the process between the VL cutting unit 40 and the TR cutting unit 50, a C process in which the end cutting bar 20b is directly conveyed from the VL cutting unit 40 to the TR cutting unit 50 is also allowed.

  The operation flow shown in FIG. 7 shows an example. Regarding the order of movement of the CR transport unit 30, the VL cutting rod 20b is moved to the TR cutting unit after the work process in the VL cutting unit 40 is completed. Which of these procedures is selected as to whether it is transported to 50 or once transported to the rack 60 and temporarily detained and then transported to the TR cutting unit 50 depends on work efficiency and other operations Judgment will be made in view of the situation.

Thus, according to the volume reduction method of the used control rod which concerns on this invention, cutting | disconnection (VL cutting | disconnection) of the velocity limit part 25 which is the terminal part of the control rod 20a, and the length of the tie rod part 22 along a longitudinal direction Cutting (TR cutting) proceeds simultaneously. As a result, even if there are a large number of used control rods 20a to be subjected to volume reduction processing, the volume reduction processing can be efficiently completed in a short period of time.
Furthermore, a mechanism using a moving blade (blade) 42 is used in the VL cutting unit 40 (first cutting portion) that cuts the velocity limit portion 25 (VL cutting), thereby reducing the amount of fine particles generated during cutting. Can be made.
The TR cutting unit 50 (second cutting part) that performs vertical cutting (TR cutting) of the tie rod part 22 is hermetically sealed by the partition wall 53, so that the fine particles generated during cutting are prevented from diffusing into the pool. The

It is a side view which shows the whole structure of the volume reduction system of the used control rod which concerns on embodiment of this invention. It is a top view which shows the whole structure of the volume reduction system of the control rod which concerns on embodiment of this invention. It is the whole control rod perspective view showing the state before volume reduction by the present invention. It is sectional drawing of a control rod which shows the state fixed to TR cutting | disconnection unit (2nd cutting part) of this embodiment. (A) (c) (e) is explanatory drawing showing a series of operation | movement of terminal cutting | disconnection (VL cutting | disconnection) of the control rod in a VL cutting | disconnection unit (1st cutting part) seen from the cross-sectional direction of the control rod. (B) (d) (f) is explanatory drawing showing the same operation | movement seen from the cross-sectional direction of the cutter. (A)-(c) is explanatory drawing showing a series of operation | movement of the vertical cutting | disconnection (TR cutting | disconnection) of a control rod seen from the side surface direction of TR cutting | disconnection unit (2nd cutting part), (d) ( e) It is explanatory drawing showing the operation | movement seen from the cross-sectional direction of the control rod. It is a flowchart which shows the operation | movement procedure of the volume reduction method of the used control rod which concerns on embodiment of this invention.

Explanation of symbols

20a (20) Control rod 20b (20) VL cutting rod (end cutting rod)
20c (20) TR cutting piece (vertical cutting piece)
22 Tie-rod part (terminal part)
23 Blade section 25 Velocity limit section 30 CR transport section (transport section)
40 VL cutting unit (first cutting part)
42a Fixed blade 42b Moving blade (blade)
50 TR cutting unit (second cutting unit)
52 Thermal cutting means 53 Bulkhead 54 Purification means 58 Opening / closing door 60 Rack 70 Storage container F Filter L Pool S Volume reduction system for used control rod

Claims (5)

In a system for reducing the volume of used control rods taken out of nuclear power plant reactors in a pool filled with water,
A first cutting portion that cuts a longitudinal end portion of the control rod into an end cutting rod;
A second cutting part that is arranged at a position different from the first cutting part and cuts the end cutting bar along the longitudinal direction into a longitudinal cutting piece;
A rack for mounting the control rod and / or the end cutting rod;
A storage container for storing the longitudinally cut pieces;
A transport unit capable of transporting the control rod, the end cutting bar or the vertical cut piece to the first cutting unit, the second cutting unit, the rack and the storage container; Prepared,
The first cutting unit performs the cutting by shear moving a blade, and the second cutting unit performs the cutting in a space isolated inside the pool ,
A period until the cutting in the second cutting section is completed,
The transport unit transports the control rod to the first cutting unit, and transports the cut end cutting bar to the rack after the cutting in the first cutting unit. Volume reduction system for finished control rods.   The used control rod volume reduction system according to claim 1, wherein the second cutting unit performs the cutting by moving a thermal cutting unit. The second cutting part further includes:
A partition wall separating the conveyed end cutting rod and the thermal cutting means from the outside;
The volume reduction system for used control rods according to claim 2, further comprising a purifying unit that collects fine particles generated during use of the thermal cutting unit and purifies the inside of the second cutting unit.   The said conveyance part can hold | grip any one among the said control rod, an edge part cutting bar, or a vertical cut piece, and can change the position to hold | grip in the vertical direction. The volume reduction system of the used control rod of any one item | term. In a method of reducing the volume of a used control rod taken out of a nuclear power plant reactor in a pool filled with water,
Transporting the control rod from the rack to the first cutting portion, cutting the end portion by shearing by the movement of the blade to form an end cutting rod;
Returning the end cutting bar from the first cutting section to the rack;
The end cutting bar is transported from the rack to a second cutting unit disposed in a space different from the first cutting unit and isolated in the pool, and cut along the longitudinal direction. To make a vertical cut piece,
Look including the the steps of receiving by conveying the longitudinal cut pieces container from said second cutting portion,
A period until the cutting in the second cutting section is completed,
The used control comprising transporting the control rod to the first cutting unit, and transporting the cut end cutting rod to the rack after execution of the cutting in the first cutting unit. How to reduce the volume of the stick.

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