JPH1164588A - Volume reducing treatment method and volume reducing treatment device for radioactive metal waste containing zirconium alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent firing of zircaloy fine in the compression and the transfer to a capsule carrying-out vessel with excellent remote controllability and maintenance property by charging a capsule into a cavity from the lower part, and pressing it by a pressing bar to compress and volume-reduce the capsule. SOLUTION: A capsule C is placed on the center part of a base 21 by remote control by the drive of the cylinder device 23 of a movable truck 2. A metal mold 22 is lowered by the reverse drive of the cylinder device 24 to charge the capsule C into a cavity 22C, and a capsule volume-reducing space S is formed. The capsule volume-reducing space S is laid in a sealed state by interposing a shield member. The air in the capsule volume-reducing space S is sucked by a degassing means 5, and an inert gas is introduced in the vacuum state by an inert gas supplying means 6. A piston 34 is lowered by the drive of a compressing mechanism 33, and a pressing bar 23 is lowered according to it to compress the capsule C into a volume-reduced capsule. Even when the capsule C is broken in this compression, zircaloy fine is never ignited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reduces the volume of radioactive metal waste containing zirconium alloys such as zircaloy fuel cladding and used metal materials after reprocessing of spent fuel for light water reactors. The present invention relates to a method and an apparatus for reducing the volume of radioactive metal waste containing a zirconium alloy to be treated.

[0002]

2. Description of the Related Art Zircaloy is an alloy mainly composed of zirconium, and has a small thermal neutron absorption cross-sectional area. Therefore, it is widely used as a reactor material, and is particularly favorably used for a fuel cladding tube of a nuclear reactor. . When reprocessing, for example, fuel for a light water reactor loaded in such a fuel cladding made of Zircaloy, first, an assembly of the fuel cladding loaded with used fuel rods is divided into several cm units. The obtained flakes are put into a melting tank, and nuclear fuel material and cladding shears (hereinafter referred to as Zircaloy Hull) are placed in the melting tank.
And assembly parts (hereinafter referred to as hardware). When the fuel cladding tube is cut, a large amount of zirconium alloy fines (dust) is generated from the cut end, and it is expected that a considerable amount of the fines will accompany the zircaloy hull and be carried to the subsequent process.

[0003] The separated nuclear fuel material is sent to a processing step for reuse, but radioactive metal waste such as zircaloy hull and hardware is stored as it is in a stainless steel storage container called a hull can. And stored in storage facilities. However, the number of hull cans in which zircaloy hulls are stored increases each time spent nuclear fuel is reprocessed, so that there is a problem that the storage facility is quickly filled up. Therefore, attempts have been made to reduce the volume of storage space for radioactive metal waste such as zircaloy hulls, thereby reducing the storage space.

By the way, in addition to the fine zirconium alloy generated at the time of cutting the fuel cladding tube, fines are generated from zircaloy, which is a zirconium alloy, when compressing and reducing the volume of radioactive metal waste. Since the fine is highly ignitable, shutting off the atmosphere is an effective measure when compressing and reducing the volume.

[0005] As a measure for shutting off the atmosphere, various methods of compressing and reducing the volume in an atmosphere of an inert gas or in water have been proposed. In the former inert gas atmosphere, combustion does not occur because of the absence of oxygen.However, in order to completely replace the interior of the room containing the volume reduction equipment with the inert gas, a large amount of the inert gas is required. However, there is a problem that the

[0006] The latter method of compressing in water is effective for preventing ignition, but it is necessary to completely remove the charged water since water is charged in the compacted piece. Therefore, the compacted piece is stored in a state where water remains, but if the storage is performed for a long period of time, there is a problem that water is irradiated with radiation and hydrogen gas is generated.

In recent years, zircaloy hull and hardware are housed in a cylindrical container (capsule) made of stainless steel, and the zircaloy hull and the like housed in the capsule are mechanically pressed together with the capsule in a mold (uniaxial compression). Thus, a so-called capsule press processing method in which a plurality of objects to be compressed are housed and stored in a container called a canister has been attracting attention. If such a capsule press method is used, the volume of the zircaloy hull and hardware is reduced in a sealed state, so that fines are effectively prevented from scattering into the atmosphere, and when the inside of the container is maintained in a vacuum. ,
It is also said that ignition is effectively suppressed.

[0008]

However, in the above capsule press processing, the capsule may be broken during the press processing, and as a result, the fine Zircaloy hull may leak from the capsule to the atmosphere.

Therefore, a mold having a cavity for accommodating a capsule such as Zircaloy Hull is used. After the capsule is loaded into the cavity of the mold, the mold is moved to the lower part of the piston rod, It is conceivable to insert a piston rod into the cavity and press it with a press machine, thereby compressing and reducing the volume of the capsule in the cavity. However, in this method, the volume of the capsule is reduced while air remains in the cavity, so that there is a possibility of ignition during the pressing process. In addition, in order to insert the piston rod into the cavity, it is necessary to perform extremely high-precision mold position control, which consumes a great deal of time for mold positioning and speeds up volume reduction processing. It has a problem that it lacks.

[0010] In order to solve such inconvenience,
The mold is set in the press machine so that the center axis of the mold cavity coincides with the center axis of the piston rod, and after the capsule is inserted into the cavity, the piston rod is lowered to enter the cavity, In this state, it is conceivable that, after the closed space in the cavity is set to an atmosphere in which a vacuum or an inert gas is replaced, the capsule in the closed space is compressed and reduced by the piston by lowering the piston rod.

By adopting such a volume reduction processing apparatus, it is not necessary to perform the above-mentioned high-precision fixed position control of the mold. However, it is necessary to increase the size of the compression apparatus, the mold, the packing for maintaining the vacuum, and the like. Has a problem in the maintenance of the piston rod.

The above-mentioned volume reduction processing apparatus is provided in a room called a cell where radiation leakage is shielded, and the operation management is performed by remote control from outside the cell. In addition to the above, it is desirable that the maintainability is good so that the repair of the device can be easily performed.

Further, when taking out the volume-reducing capsule from the mold after the volume-reducing treatment, the mold is raised with the piston rod lowered, and at this time, the volume-reducing capsule is exposed to the atmosphere. As a result, frictional energy is generated when the capsule is extruded from the cavity, and thermal energy is generated by an impact when the capsule is dropped from the cavity to the base. In this state, Zircaloy fine may be ignited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is based on the premise that a capsule press process is performed, without performing high-precision positioning control of a mold loaded with capsules. Reduced volume of radioactive metal waste, including zirconium alloy, which can prevent zircaloy fine firing reliably in the process of transferring capsules to the compression and capsule unloading containers, with excellent remote controllability and maintainability. It is an object to provide a processing method and a volume reduction processing device.

[0015]

According to a first aspect of the present invention, there is provided a method for reducing the volume of radioactive metal waste containing a zirconium alloy, wherein the radioactive metal waste containing a zirconium alloy is charged into a capsule. In a method for reducing the volume of radioactive waste containing a zirconium alloy to be loaded into a cavity of a mold, compressed and reduced in volume, the mold and a press inserted in sliding contact with the cavity of the mold are provided. Using a movable carriage or a movable gantry having a rod, the capsule is loaded into the cavity from below, and then the capsule in the cavity is compressed and reduced by pressing the push rod in a compression device. is there.

According to the present invention, the movable carriage or the movable base is provided with a mold having a cavity for loading a capsule, and the cavity of the mold is provided with a push rod for compressing and reducing the volume of the capsule. Since the capsule is loaded, the compression rod is pressed by the compression device in a state where the capsule is loaded in the cavity, so that the capsule in the cavity is compressed and reduced in volume by the rod.

Since the push rod is previously inserted into the cavity of the mold, it is not necessary to insert the push rod into the cavity every time the capsule is loaded into the cavity.
It is not necessary to perform a highly accurate positioning operation of the movable carriage or the movable gantry with respect to the compression device, and there is no inconvenience that the capsule volume reduction process takes time due to the highly accurate positioning operation of the movable trolley or the movable gantry.

Further, since parts which are easy to be maintained, such as a mold and a push rod, are provided on a movable movable carriage or a movable gantry, the parts are easily pulled out from the compression device during maintenance work. It can be carried and maintenance is easy.

The method for reducing the volume of radioactive metal waste containing a zirconium alloy according to the second aspect of the present invention is the method for reducing the volume of radioactive metal waste containing a zirconium alloy according to the first aspect. A capsule loading step of loading capsules into the capsule volume reducing space formed by the cavity of the movable frame, after sealing the inside of the capsule volume reducing space of the movable cart or the movable frame mounted on the compression device, Decompressing air or replacing the air with an inert gas, and then reducing the volume of the capsule volume reducing space by lowering the push rod to convert the capsule into a volume reducing capsule. After raising the mold on the gantry, the unloading container mounting step of mounting the capsule unloading container directly below the die on the base, the movable cart or After lowering the mold on the moving stand to make the inside of the capsule unloading container hermetically sealed, the air in the capsule unloading container is degassed or replaced with an inert gas, and then the push rod is lowered to lower the volume-reduced capsule. It is characterized by comprising a capsule transfer step of transferring the capsule to the capsule unloading container, and a capsule unloading step of unloading the reduced volume capsule from the capsule unloading container.

According to the present invention, in the capsule loading step, the capsule generated at the capsule generating location is loaded into the capsule reduction space of the movable carriage or the movable base, and in the compression reduction step, the capsule reduction of the movable carriage or the movable base is performed. In the state where the air in the storage space is degassed or replaced with an inert gas, the capsule volume is reduced by reducing the capacity of the capsule reduction space. The capsule is mounted directly below the mold on the table, and in the capsule transfer process, the reduced volume capsule is transferred to the capsule discharge container by descending the push rod in a state where the inside of the capsule discharge container is degassed or replaced with an inert gas. Then, in the last capsule unloading step, the reduced volume capsule is unloaded from the capsule unloading container.

As described above, in the series of steps for reducing the volume of the capsule from loading Zircaloy fine to unloading the reduced volume capsule, the compression volume reduction step which generates heat due to frictional heat or the like and the capsule transfer are performed. In the process, the capsule containing the zircaloy hull and the volume-reduced capsule after the compression volume reduction process do not come into direct contact with the outside air, and the zircaloy fine caused by the contact with the outside air in the presence of ignition energy Ignition is reliably prevented.

According to a third aspect of the present invention, there is provided a method for reducing the volume of a radioactive metal waste containing a zirconium alloy, wherein the radioactive metal waste containing a zirconium alloy is charged into a capsule.
This capsule is loaded into the mold cavity and compressed,
In the method for reducing the volume of radioactive waste containing a zirconium alloy to be reduced in volume, a capsule is loaded from above into a cavity of the mold mounted on a movable carriage or a movable base, and then pressed into the cavity of the mold. After the rod is inserted, the capsule in the cavity is compressed and reduced in volume by pressing the push rod in a compression device.

According to the present invention, the operation of extracting the push rod from the mold before loading the capsule into the mold, loading the capsule into the mold, and then loading the push rod into the cavity of the mold is performed. Thereby, the capsule can be loaded into the cavity of the mold, and the monitoring and safety at the time of loading the capsule are improved.

According to a fourth aspect of the present invention, there is provided an apparatus for reducing the volume of radioactive metal waste containing a zirconium alloy, wherein the radioactive metal waste containing a zirconium alloy is charged into a capsule.
An apparatus for reducing the volume of radioactive waste containing a zirconium alloy for compressing and reducing the volume of a capsule, comprising: a movable movable carriage or a movable platform; and a capsule loaded on the movable carriage or the movable platform. A compression device for converting the reduced-capsule capsule on the movable carriage or the movable gantry in the compression device, and the movable trolley or the movable gantry includes a base, And has a cavity capable of elevating and lowering having a cavity forming a capsule volume-reducing space, and a push rod fitted into the cavity in a sliding manner from above,
The compression device has a compression mechanism for compressing and reducing the volume of the capsule in the capsule volume reduction space by pressing the push rod from above, and the capsule discharge container has a raised mold bottom surface and a base surface. And can be held in close contact with
It has a capsule accommodation hole extending in the vertical direction corresponding to the cavity.

According to this invention, since the movable carriage or the mold of the movable base is raised by the mold lifting / lowering means, a gap is formed between the bottom surface of the mold and the surface of the base. Then, the capsule containing the zircaloy hull is pushed into the gap, and the mold is lowered while being positioned in the lower part of the cavity, so that the capsule is loaded in the cavity of the mold.

Next, by pressing the push rod downward by the compression mechanism, the capsule in the cavity is compressed and reduced in volume by the push rod. Then, by raising the mold, the volume-reduced capsule rises with the cavity due to the expansion of the compressed capsule. In this state, the capsule unloading container is inserted into the gap between the mold and the base so that the capsule receiving hole is vertically opposed to the reduced volume capsule, and then the capsule unloading container is lowered by lowering the mold. It is in a state of being pressed and held between the base and the table. By lowering the push rod in this state, the volume-reduced capsule in the cavity is pushed out by the push rod, and is placed in the capsule receiving hole of the capsule carry-out container.

Then, after the mold is lifted on the movable carriage or the movable base, the capsule unloading container is unloaded from under the mold, so that the reduced volume capsule can be taken out of the capsule receiving hole.

As described above, according to the present invention, since the mold, the push rod, and the capsule unloading container are mounted on the movable carriage or the movable base, the compression device can have a simple structure, and maintenance can be performed. In addition to easy maintenance, it is easy to monitor the dies and push rods that are frequently maintained outside the compression device, and it is possible to perform maintenance and inspection at a position that is easy to work with, so that good remote operability can be obtained. . Further, since the push rod is previously inserted into the cavity of the mold, high precision is not required for positioning the movable carriage or the movable gantry to the compression device, and the operability is excellent.

According to a fifth aspect of the present invention, there is provided the apparatus for reducing the volume of radioactive metal waste containing a zirconium alloy according to the fourth aspect of the present invention. Any one of a bottomed capsule unloading container with a bottom and a bottomless capsule unloading container without a bottom is used, and when the bottomed capsule unloading container is used, the inner peripheral surface of the cavity and the pusher are used. An annular seal member is interposed between the outer peripheral surface of the rod, between the bottom surface of the mold and the surface of the base, and between the bottom surface of the mold and the upper surface of the capsule carry-out container. When a capsule unloading container is used, a seal member is interposed between the capsule unloading container and the base in addition to the interposed position of the seal member.

According to the present invention, the hermetically sealed state of the cavity in the capsule volume reducing space and the space in the capsule unloading container is reliably maintained by the sealing effect of the sealing member.

The volume reducing apparatus for radioactive metal waste containing a zirconium alloy according to claim 6 of the present invention is the above apparatus for reducing volume of radioactive metal waste containing a zirconium alloy according to claim 4 or 5. Either one or both of a deaeration means for deaeration of air in the volume reduction space and the capsule unloading container and an inert gas supply means for replacing the air with an inert gas is provided. It is a feature.

According to the present invention, since the inside of the capsule volume reduction space of the cavity is maintained in a vacuum state by the degassing means or the air is replaced by the inert gas by the inert gas supply means, the capsule is compressed. Even if the Zircaloy Fine is broken in the capsule volume reduction space and scatters into the capsule volume reduction space, the firing of the Zircaloy Fine in the capsule volume reduction space is reliably prevented, and the capsule discharge container for the volume reduction capsule During transfer to Zircaloy Fine, the firing of Zircaloy Fine is reliably prevented.

[0033]

FIG. 1 is an explanatory side view showing an example of a spent fuel assembly of a light water reactor to be processed by a volume reduction processing apparatus. As shown in this figure, a spent fuel assembly N is provided in a zircaloy cladding tube N1 enclosing a fuel rod, an upper nozzle N2 provided in an upper portion of the cladding tube N1, and in a lower portion thereof. A lower nozzle N3,
A support grid (hardware) N4 for supporting the cladding tube N1 in an assembled state is provided.

When reprocessing spent fuel, the fuel assembly N as described above is first sheared into small pieces of several centimeters. The sheared pieces are put into a dissolving tank filled with a predetermined dissolving solution, and separated into nuclear fuel material, cut pieces of the cladding tube N1 and so-called zircaloy hulls of the hardware N4 in the dissolving tank. You. The separated nuclear fuel material is sent to a processing step for reuse, and the remaining zircaloy hull and the like are reduced in volume by the volume reduction processing apparatus of the present invention and stored.

FIG. 2 is a perspective view showing an example of a capsule for accommodating the above-mentioned zircaloy hull and the like. As shown in this figure, the capsule C is a capsule body C having a cylindrical bottom.
1 and a lid C2 for closing the upper opening of the capsule body C1. Such a capsule body C
The above-mentioned Zircaloy hull is loaded into the inside 1 and the volume is reduced by the volume reduction processing apparatus according to the present invention in a state where it is closed by the lid C2.

FIGS. 3 and 4 are explanatory views showing one embodiment of the volume reduction processing apparatus according to the present invention. FIG. 3 shows the capsule volume reduction of the movable trolley 2 into which the capsule C is loaded into the compression device 3. FIG. 4 shows a state in which the capsule is loaded in the space S, and FIG. 4 shows a state in which the capsule unloading container 4 is mounted on the movable carriage 2 and the reduced volume capsule Ca is pushed out into the capsule unloading container 4 by the push rod 23.

In this embodiment, the movable carriage and the movable carriage 2 in the movable carriage will be described, and the description of the movable carriage will be omitted. The movable gantry is different from the movable trolley 2 in that the movable gantry is not provided with wheels. Therefore, when the movable gantry is moved, an operation of mounting the movable gantry on another moving means or the like is necessary. Is formed substantially the same as the movable carriage.

As shown in FIGS. 3 and 4, the volume reduction processing device 1 comprises a movable carriage 2, a compression device 3, a capsule unloading container 4 (FIG. 4), a degassing means 5, and an inert gas supply. Means 6
And a basic configuration including:

The movable carriage 2 carries a mold 22, a push rod 23, a cylinder device 24, etc., described later, out of the compression device 3 for maintenance and inspection outside the compression device 3. The device 3 is for reducing the volume of the capsule C contained in the movable carriage 2. The compression device 3 includes a predetermined number of columns 31 erected on the substrate 7 on the base B and a gantry 32 supported by the columns 31, and a compression mechanism 33 is installed on the gantry 32. A piston 34 of the compression mechanism 33 penetrates the gantry 32 and hangs downward. This piston 34 has a compression mechanism 33
The capsule C housed in the movable carriage 2 is compressed and reduced in volume when it is moved up and down by the drive of.

The capsule unloading container (capsulated container unloading container) 4 is for accommodating the reduced volume capsule Ca reduced on the movable carriage 2 in the compression device 3 and discharging it from the compression device 3. Yes, it is formed separately from the movable cart 2 and the compression device 3 and may be mounted on the movable cart 2 only when the volume-reduced capsule Ca is carried out, or may be always mounted on the movable cart 2. FIG. 4 shows a state in which the capsule unloading container 4 is mounted on the movable carriage 2.

The degassing means 5 is for sucking air in the capsule volume reduction space of the movable carriage 2 carried into the compression device 3 to produce a vacuum state. The gas supply means 6 is for introducing an inert gas into the space for reducing the volume of the capsule.

Hereinafter, such a volume reduction processing apparatus 1 will be described in detail with reference to FIGS. 5 and 6, and with reference to FIGS. 3 and 4 as necessary.

FIGS. 5 and 6 are partially cutaway perspective views showing one embodiment of the movable carriage 2. FIG. 5 shows a capsule C loaded in a capsule volume reduction space S in a mold 22. FIG. 6 shows a state in which the volume-reduced capsule Ca has been taken out of the movable carriage 2 via the capsule carrying-out container 4.

As shown in FIG. 5, the movable carriage 2 includes a flat base 21, a cylindrical mold 22 disposed at the center of the base 21, and It has a cylindrical push rod 23 having a fitted lower stopper, a plurality of cylinder devices 24 erected on the base 21, and a plurality of wheels 25 provided on the bottom of the base 21. . In addition,
In the present embodiment, the cylinder device 24 is provided on the fusible volume-decreasing trolley 2, but may be provided on the substrate 7 or the base B instead. In the case where the capsule unloading container 4 is still mounted on the movable trolley 2, the capsule unloading container 4 is moved to a position away from the mold 22 on the movable trolley 2 by means (not shown), and then only the reduced volume capsule Ca is unloaded. What is necessary is just to take it out of the container 4. When the cylinder device 24 is provided on the foundation B, the mold 22 is lifted and lowered outside the compression device 3. The base 21
The portion corresponding to the push rod 23 at the center is formed solid, and the capsule C is placed on this portion. The base 21 is configured to withstand the compression of the capsule C by the push rod 23.

The cylinder device 24 includes four cylinders 24a erected at four corners of the base 21 and two cylinders 2a.
4a, and a piston rod 24b projecting upward from the mold main body 2a.
2a and a flange 22b fixed to the outer periphery of the upper portion thereof and having a rectangular shape in plan view. The flange 22b is supported on the top of each cylinder 24a, and the piston rod 24 is driven by the cylinder device 24.
The mold 22 is moved up and down by moving up and down b.
5 shows a state in which the mold 22 is lowered, and FIG.
Respectively indicate a state in which has risen. In the present embodiment, a method using a cylinder for elevating and lowering the mold 22 is employed, but another elevating method using a ball screw or the like may be used instead of the cylinder method.

A central portion of the mold 22 has a circular cavity 22c in a plan view, which penetrates in the vertical direction, and the push rod 23 is fitted into the cavity 22c in a sliding contact state. At the top of the push rod 23, a head 23a having a diameter larger than that of the push rod 23 is formed. The head 23a allows the push rod 23 to rise together with the mold 22 when it rises. The part 23a is a push rod 23
It plays a role of keeping it from falling down. The capsule volume reduction space S is formed in a space surrounded by the lower end surface of the push rod 23, the inner peripheral surface of the cavity 22c, and the surface of the base 21.

Accordingly, the movable carriage 2 is carried into the compression device 3 (FIG. 3), and the compression mechanism 33 drives the piston 3 with the capsule C accommodated in the capsule volume reduction space S.
4, the push rod 23 is moved to the piston 34.
And the capsule C is compressed, and the volume of the capsule C is reduced.

An annular sealing member 22d made of synthetic resin or synthetic rubber is mounted on the inner peripheral surface of the upper portion of the cavity 22c, and a similar sealing member is mounted on the lower surface of the mold body 22a. 22e is mounted, whereby the mold 22 is lowered, and the lower surface thereof is brought into contact with the surface of the base 21, so that the inside of the capsule volume reduction space S is sealed. Therefore, even if the capsule C is damaged by the compression volume reduction, the Zircaloy fine does not leak from the capsule volume reduction space S to the outside.

The wheels 25 (FIG. 5) can be freely retracted from the bottom surface of the base 21 by a wheel retracting mechanism (not shown) provided in the base 21. When the movable trolley 2 is pulled out of the compression device 3 for maintenance and inspection, the wheels 25 protrude from the bottom of the base 21 to the outside, and in this state, are moved by being pushed by a self-propelled pusher machine (not shown). And movable cart 2
Is carried into the compression device 3, the wheels 25 are stored in the base 21, so that the bottom surface of the base 21 directly contacts the substrate 7 of the compression device 3. on the other hand,
In the case of a movable gantry, it can be moved by a transfer means (not shown) such as a rack and a pinion.

In the present embodiment, as shown in FIG. 6, the capsule carrying container 4 has a bottom. Specifically, the capsule carrying-out container 4 is formed of a circular body having a height dimension capable of accommodating the compressed volume-reducing capsule Ca. At the center of the capsule unloading container 4, a bottomed capsule receiving hole 41 having a diameter slightly larger than the diameter of the reduced volume capsule Ca is provided. As shown by a two-dot chain line in FIG.
2 is inserted into the lower part of the mold 22 when the
This is for receiving the volume-reduced capsule Ca attached to the inner peripheral surface of 2c and taking it out. Then, the reduced volume capsule Ca attached to the inner peripheral surface of the cavity 22c is pushed downward by the lowering of the push rod 23 via the piston 34 driven by the compression mechanism 33, and is stored in the capsule receiving hole 41.

In this embodiment, the capsule carrying container 4
The one having the bottom with the capsule housing hole 41 was used as
The present invention is not limited to the case where the capsule housing hole 41 has a bottom, but may be one having a through hole (a bottomless capsule unloading container). However, when providing a through hole,
It is necessary to provide an annular seal member on the bottom surface of the capsule unloading container 4 and make the inside of the through hole a closed space with the capsule unloading container 4 mounted on the lower part of the mold 22. When the through-hole is provided, the operation of taking out the volume-reduced capsule Ca from the hole becomes easy.

As shown in FIG. 3, the deaeration means 5 includes a deaeration line 51 communicating with the capsule volume reduction space S of the movable carriage 2 carried into the compression device 3, and a downstream side of the deaeration line 51. And a vacuum pump 52 provided at the end. Immediately upstream of the deaeration line 51, a stop valve 53 is provided, and a diffusion tube 54 is branched from the deaeration line 51 upstream of the stop valve 53. Is attached.

As shown in FIG. 3, the inert gas supply means 6 includes an inert gas source 61 and the inert gas source 6.
1 and a gas line 62 communicating between the capsule volume reduction space S
Are formed. A pressure reducing valve 63 is provided immediately downstream of the inert gas source 61, and a stop valve 64 is provided downstream of the pressure reducing valve 63. When the stop valve 64 is opened, the internal pressure of the inert gas source 61 is reduced. An inert gas is introduced into the capsule volume reduction space S.

By opening the stop valve 53 while the vacuum pump 52 is driven, the air in the capsule volume reducing space S shown in FIG. 3 is sucked, and the capsule volume reducing space S is reduced in pressure. When the inside of the capsule volume reduction space S reaches a predetermined degree of vacuum, the stop valve 53 is closed, and then the stop valve 64 on the inert gas supply means 6 side is opened. Is being introduced.

FIG. 7 is a cross-sectional view for explaining the operation of the present invention, and shows the case of the movable carriage 2. FIG. 7A shows that the capsule C in which the zircaloy hull is stored is placed in the cavity 22 of the movable carriage 2.
(b) is a state immediately before loading into the cavity 22c (the first half of the capsule loading step), (b) is a state in which the capsule C is loaded into the cavity 22c (the latter half of the capsule loading step), (c)
The state where the capsule C in the cavity 22c is compressed by the compression device 3 to form the reduced volume capsule Ca (compression reduction step), and (d) the capsule unloading container 4 is mounted just below the mold 22. (E) is the reduced volume capsule C in the cavity 22c.
(a) shows a state in which the capsule a has been transferred to the capsule unloading container 4 (the latter half of the capsule transfer step), and (f) shows a state in which the reduced volume capsule Ca has been removed from the capsule unloading container 4 (unloading step). .

First, as shown in FIG. 7A, the movable carriage 2 is housed in advance in the compression device 3 in which the piston 34 is raised. In this state, the wheels 25 of the movable carriage 2
(FIG. 5) is stored in the base 21. Then, the piston rod 24b is protruded upward by the driving of the cylinder device 24 of the movable carriage 2, and in this state, the capsule C is placed at the center of the base 21 by remote operation of a robot arm or the like, and just below the cavity 22c. Is located in the state. In the present embodiment, the capsule C is set immediately below the cavity 22C in a state where the movable carriage 2 is located in the compression device 3, but the movable carriage 2 is moved to a position outside the compression device 3 where monitoring is excellent. Alternatively, the capsule C may be set directly below the cavity 22C.

Then, the mold 22 is lowered by the piston rod 24b being immersed in the cylinder 24a by the reverse drive of the cylinder device 24, whereby the capsule C is moved into the cavity 22c as shown in FIG. It will be in the state loaded in. In this state, since the lower end surface of the push rod 23 abuts the capsule C and is prevented from descending, the push rod 23 protrudes upward relative to the mold 22. In this state, a capsule volume reduction space S surrounded by the bottom surface of the push rod 23, the inner peripheral surface of the cavity 22c, and the surface of the base 21 is formed, and the capsule C is formed in the capsule volume reduction space S.
It has been loaded inside.

Further, a seal member 22d is interposed between the inner peripheral surface of the cavity 22c and the outer peripheral surface of the push rod 23, and also between the bottom surface of the mold 22 and the surface of the base 21. Since the seal member 22e is interposed, the capsule volume reduction space S is a closed space. Further, the inside of the capsule volume reducing space S is communicated with the deaeration line 51 and the gas line 62 by connecting means (not shown).

Next, the vacuum pump 52 (FIG. 4) is operated, the stop valve 53 on the side of the degassing means 5 is opened, and the air in the capsule volume reduction space S is sucked. Thereafter, the stop valve 53 is closed, and the stop valve 64 on the side of the inert gas supply means 6 is opened in a state where the vacuum atmosphere of the capsule volume reduction space S is maintained, whereby the inert gas from the inert gas source 61 is opened. Gas is introduced into the capsule volume reduction space S.

Next, the piston 34 is lowered by the driving of the compression mechanism 33, and the push rod 23 is lowered by this.
As shown in FIG. 7C, the capsule C in the capsule volume reduction space S is compressed into a volume reduction capsule Ca. At the time of this compression, even if the zircaloy fine inside leaks into the capsule volume reducing space S due to the breakage of the capsule C, the inert gas is filled in the capsule volume reducing space S, so that the zircaloy fine does not ignite. Absent. And volume reduction capsule C
a is a diameter expansion by compression volume reduction, and the outer peripheral surface is a cavity 22c.
Is in close contact with the inner peripheral surface of the.

Then, after the piston 34 is raised, the mold 22 is raised by the projection of the piston rod 24b driven by the cylinder device 24. Then, the volume-reduced capsule Ca is held in the capsule volume-reduced space S while the mold 2 is kept.
2 and a gap is formed between the bottom surface of the mold 22 and the surface of the base 21. The capsule unloading container 4 is pushed into this gap by a pusher machine or the like, and (d) in FIG.
As shown in FIG.
1 is positioned so as to face directly below the volume reduction capsule Ca.

Thereafter, the space in the capsule carrying-out container 4 is evacuated and then replaced with an inert gas. Then, the piston 34 is lowered again by driving the compression mechanism 33, and the push rod 23 is pressed downward. As a result, (e) of FIG.
As shown in the figure, the volume reduction capsule C in the capsule volume reduction space S
a is pushed downward and is accommodated in the capsule accommodation hole 41 of the capsule carry-out container 4. When the volume-reduced capsule Ca is extruded downward from the cavity 22c and transferred to the capsule unloading container 4, heat may be generated due to friction between the cavity 22c and the volume-reduced capsule Ca. Since 41 is an inert gas atmosphere, ignition by Zircaloy Fine is reliably suppressed. Next, the piston 34 is raised by driving the compression mechanism 33.

Then, as shown in FIG. 7F, the mold 22 is raised by driving the cylinder device 24, and the capsule unloading container 4 is moved to the mold 22 by a pusher machine or the like (not shown).
Then, the reduced volume capsule Ca in the capsule housing hole 41 is moved to a predetermined storage location by remote control of a robot arm or the like.

In the above series of operations, the push bar 23
Since it is usually loaded in the cavity 22c of the mold 22 of the movable trolley 2, a high positioning accuracy for the compression operation in the compression device 3 is not required, which is extremely effective in performing the compression operation efficiently. is there.

Also, at the time of the compression operation in the compression device 3,
Since the inert gas is introduced into the capsule volume reduction space S in the cavity 22c in which the capsule C is loaded, even if the zircaloy fine leaks from the capsule C due to the destruction of the capsule C due to the compression volume reduction, it does not cause any problem. Ignition is reliably prevented.

In addition, the reduced volume capsule Ca obtained as a result of the compression operation is transferred into the capsule receiving hole 41 of the capsule unloading container 4 filled with the inert gas. Firing during the take-out operation is reliably prevented.

As described above, according to the present invention, in a series of volume reduction processing of zircaloy hull, the compression operation by remote control can be performed extremely efficiently, and ignition by zircaloy fine is reliably prevented. Therefore, the effect of safely reducing the volume of Zircaloy Hull is great.

In the above-described embodiment, the operation of loading the capsule C into the cavity 22C is performed from the lower part of the mold 22, but instead of this, the movable carriage or the metal mounted on the movable platform is used. The capsule may be loaded into the cavity of the mold from above, a push rod may be loaded into the cavity, and the compression rod may be pressed by a compression device to reduce the volume of the capsule in the cavity.
By doing so, the push rod is withdrawn from the mold before the capsule is loaded into the mold, and after the capsule is loaded into the mold, the push rod is loaded into the cavity of the mold, whereby the capsule is inserted into the cavity of the capsule. Since the loading is performed, the capsule can be loaded into the cavity from above the mold for easy visual observation, and the monitoring and safety at the time of loading the capsule can be further improved.

[0069]

According to the method for reducing the volume of radioactive metal waste containing a zirconium alloy according to the first aspect of the present invention, a movable carriage or a movable base is provided with a mold having a cavity for loading a capsule. In addition, since a push rod for compressing and reducing the volume of the capsule is fitted in the cavity of the mold, the movable carriage or the movable base is loaded into the compression device with the capsule loaded in the cavity, and the compression device is By pressing the push rod, the capsule in the cavity is compressed and reduced in volume by the push rod.

Since the push rod is previously inserted into the cavity of the mold, it is not necessary to insert the push rod into the cavity every time the capsule is loaded into the cavity.
It is not necessary to perform a highly accurate positioning operation on the truck, and the capsule volume reduction processing can be performed safely and efficiently.

Parts that are easily subject to maintenance, such as a mold and a push rod, are provided on a movable movable carriage or a movable gantry, and the movable trolley or the movable gantry is taken out of the compression device except during a compression operation. Therefore, the maintainability is improved, the maintenance of the apparatus can be easily performed, the radiation exposure of maintenance personnel during maintenance is greatly reduced, and the safety can be improved.

According to the method for reducing the volume of radioactive metal waste containing a zirconium alloy according to the second aspect of the present invention, in the capsule loading step, the capsules are loaded into the movable vehicle or the capsule reduction space of the movable gantry and compressed. In the volume reduction process, the capsule volume reduction process is performed by reducing the volume of the capsule volume reduction space in a state where the air in the capsule volume reduction space of the movable carriage or the movable base is degassed or replaced with an inert gas. In the capsule transfer step, the volume-reduced capsule is transferred on a movable carriage or a movable gantry to a capsule discharge container whose internal volume is degassed or replaced with an inert gas, and the final capsule unloading step is performed. , Because the reduced volume capsule is unloaded from the capsule unloading container,
In a series of steps for reducing the volume of the capsule from loading the capsule to unloading the reduced volume capsule, the capsule containing the zircaloy hull and the reduced volume capsule after the compression reduction are in direct contact with the outside air. Opportunities are reduced, and ignition of Zircaloy Fine caused by contact with outside air in the presence of ignition energy is reliably prevented.

According to the apparatus for reducing the volume of radioactive metal waste containing a zirconium alloy according to the fourth aspect of the present invention, the mold of the movable carriage or the movable gantry is raised by the mold lifting / lowering means, whereby the mold is removed. Since a gap is formed between the bottom surface and the surface of the base, the capsule containing Zircaloy Hull is pushed into this gap, and the mold is lowered in the state where it is located at the bottom in the cavity, so that the capsule is Is loaded into the mold cavity.

Then, by pressing the push rod downward by the compression mechanism, the capsule in the cavity is compressed by the push rod to reduce its volume.

Next, by raising the mold, the volume-reduced capsule rises with the cavity due to the expansion of the diameter of the compressed capsule. In this state, the capsule unloading container is inserted into the gap between the mold and the base so that the capsule receiving hole is vertically opposed to the reduced volume capsule, and then the capsule unloading container is lowered by lowering the mold. It is in a state of being pressed and held between the base and the table. By lowering the push rod in this state, the volume-reduced capsule in the cavity is pushed out by the push rod, and is placed in the capsule receiving hole of the capsule carry-out container.

Then, after the mold is raised on the movable carriage or the movable base, the capsule unloading container is taken out from under the mold, so that the reduced volume capsule can be taken out of the capsule receiving hole.

According to the method for reducing the volume of radioactive metal waste containing a zirconium alloy according to the third aspect of the present invention, the capsule is loaded from above into the cavity of the movable carriage or the mold mounted on the movable base. Since the pressing rod is inserted into the cavity, and the pressing rod is pressed in the compression device to compress and reduce the volume of the capsule in the cavity, the pressing rod is removed from the mold before the capsule is loaded into the mold. By performing the operation of extracting and loading the capsule into the mold after loading the capsule into the mold, the capsule can be loaded into the cavity from above the mold for easy visual observation, The monitoring and safety at the time of loading the capsule can be improved.

As described above, according to the fourth aspect of the present invention, since the mold, the push rod, and the capsule carry-out container are mounted on the movable carriage or the movable base, the structure of the compression device main body can be simplified. It is possible to carry out the maintenance and maintenance easily, and the frequently-operated mold and push rod can be easily moved out of the compression device to a position with good monitoring and workability, and
Maintenance and inspection can be performed reliably, remote operability for maintenance and inspection is excellent, radiation exposure of maintenance personnel during maintenance can be greatly reduced, and safety can be improved. further,
Since a push rod having a retainer downward is inserted into the mold cavity, it is not necessary to obtain high precision for positioning the movable carriage or the movable base on the compression device, and the operability for positioning is excellent. I have.

According to the apparatus for reducing the volume of radioactive metal waste containing a zirconium alloy according to the fifth aspect of the present invention, a capsule container with a bottom having a bottom as a container for carrying a capsule and a container with no bottom without a bottom are provided. If you use a container with a bottomed capsule,
An annular seal member is interposed between the inner peripheral surface of the cavity and the outer peripheral surface of the push rod, between the bottom surface of the mold and the surface of the base, and between the bottom surface of the mold and the upper surface of the capsule unloading container. However, when using a bottomless capsule unloading container, a sealing member is interposed between the capsule unloading container and the base in addition to the interposed position of the sealing member. It is possible to reliably maintain the hermetically sealed state inside the capsule volume reduction space of the cavity and the space where the volume reduction capsule is transferred to the capsule carry-out container.

According to the apparatus for reducing the volume of radioactive metal waste containing a zirconium alloy according to the sixth aspect of the present invention, the air in the space for reducing the volume of the capsule and in the space for transferring the reduced volume capsule to the container for carrying out the capsule. Since either or both of the degassing means for degassing the air and the inert gas supply means for replacing the air with the inert gas are provided, the inside of the capsule volume reduction space of the cavity is evacuated by the Even if the state is maintained or the air is replaced with inert gas by the inert gas supply means, the capsule is broken in the capsule volume reducing space by the compression process, and even if the zircaloy fine scatters in the capsule volume reducing space. , It is possible to reliably prevent the firing of Zircaloy Fine in the capsule volume reduction space, and to transfer the volume reduction capsule to the capsule carry-out container. It is possible to reliably prevent the ignition of Luke Roy fine.

[Brief description of the drawings]

FIG. 1 is an explanatory side view showing an example of a spent fuel assembly of a light water reactor to be processed by a volume reduction processing apparatus.

FIG. 2 is a perspective view showing an example of a capsule for storing a zircaloy hull or the like.

FIG. 3 is an explanatory view showing one embodiment of a volume reduction processing apparatus according to the present invention, showing a state where capsules are loaded in a capsule reduction space of a movable carriage or a movable gantry carried into a compression device. I have.

FIG. 4 is an explanatory view showing one embodiment of a volume reduction processing apparatus according to the present invention, and shows a state in which a capsule carry-out container is mounted below a mold of a movable carriage or a movable gantry.

FIG. 5 is a partially cutaway perspective view showing an embodiment of the movable carriage or the movable gantry, showing a state in which capsules are loaded in a capsule volume reduction space in a mold.

FIG. 6 is a perspective view of the movable carriage or movable base shown in FIG. 5;
This shows a state where the reduced volume capsule a has been taken out from under the mold of the movable carriage or the movable base via the capsule unloading container.

FIGS. 7A to 7F are explanatory views in cross-section for explaining the operation of the present invention.

[Explanation of symbols]

 B Base 1 Volume reduction device 2 Movable carriage or gantry 21 Base 22 Mold 22a Mold main body 22b Flange 22c Cavity 22d, 22e Seal member 23 Push rod 23a Head 24 Cylinder device 24a Cylinder 24b Piston rod 25 Wheel 3 Compression Apparatus 31 Column 32 Mount 33 Compression mechanism 34 Piston 4 Capsule unloading container 41 Capsule receiving hole 5 Deaeration means 51 Deaeration line 52 Vacuum pump 53 Stop valve 54 Dissipation pipe 55 Dissipation valve 6 Inert gas supply means 61 Inactive gas source 62 Gas line 63 Pressure reducing valve 64 Stop valve 7 Substrate S Capsule volume reduction space C Capsule C1 Capsule body C2 Lid N Fuel assembly

Claims (6)

[Claims] 1. A radioactive metal waste containing a zirconium alloy is charged into a capsule, and the capsule is loaded into a cavity of a mold, compressed, and reduced in volume. In the processing method, using a movable carriage or a movable gantry having a push rod inserted in a sliding state into the mold and the cavity of the mold, a capsule is loaded from below into the cavity, and then the above-described compression apparatus is used. A volume reducing method for radioactive metal waste containing a zirconium alloy, wherein the capsule in the cavity is compressed and reduced in volume by pressing a push rod. 2. A method for reducing the volume of radioactive metal waste containing a zirconium alloy according to claim 1, wherein a capsule is loaded into a capsule volume reducing space formed by a cavity of the movable carriage or the movable base.
After the inside of the capsule volume reduction space of the movable trolley or movable frame mounted on the compression device is sealed, the air in the capsule volume reduction space is degassed or replaced with an inert gas, and then the capsule volume reduction space is replaced. The volume is reduced by lowering the push rod to reduce the capsule into a volume-reduced capsule. The loading container mounting process for mounting directly below the mold, after lowering the mold on the movable carriage or movable platform to make the inside of the capsule discharging container hermetically sealed, the air in the capsule discharging container is degassed or replaced with an inert gas. And then lowering the push rod to transfer the reduced volume capsule to the capsule unloading container, and a capsule for unloading the reduced volume capsule from the capsule unloading container Compacting method for treating a radioactive metal waste containing zirconium alloy, comprising the descending Shi step. 3. A radioactive metal waste containing a zirconium alloy is charged into a capsule, the capsule is loaded into a cavity of a mold, compressed, and a volume of the radioactive waste containing a zirconium alloy is reduced. In the processing method, after the capsule is loaded from above into the cavity of the mold mounted on the movable carriage or the movable base, the push rod is inserted into the cavity of the mold, and then the push rod is compressed by the compression device. A method for reducing the volume of radioactive metal waste containing a zirconium alloy, comprising compressing and reducing the volume of a capsule in a cavity by pressing. 4. An apparatus for reducing the volume of a radioactive waste containing a zirconium alloy, wherein a radioactive metal waste containing a zirconium alloy is charged in a capsule, and the capsule is compressed to reduce the volume. A movable carriage or a movable base, a compression device for compressing and reducing the volume of capsules loaded on the movable carriage or the movable base to reduce the volume, and a capsule in which the reduced-capsule is transferred on the movable carriage or the movable base in the compression device. A carry-out container is provided, and the movable carriage or the movable gantry is a base, a vertically movable mold that penetrates in a vertical direction, and has a cavity that forms a capsule volume reduction space; A compression rod that presses the compression rod from above to compress and reduce the volume of the capsule in the capsule volume reduction space. Having a mechanism, the capsule unloading container can be sandwiched between the bottom surface of the raised mold and the surface of the base in close contact with each other, and has a capsule accommodation hole extending vertically corresponding to the cavity. An apparatus for reducing the volume of radioactive metal waste containing a zirconium alloy. 5. The capsule unloading container is one of a bottomed capsule unloading container having a bottom and a bottomless capsule unloading container without a bottom. When the bottomed capsule unloading container is used, An annular seal between the inner peripheral surface of the cavity and the outer peripheral surface of the push rod, between the bottom surface of the mold and the surface of the base, and between the bottom surface of the mold and the upper surface of the capsule unloading container. In the case where a member is interposed and the bottomless capsule unloading container is used, a seal member is interposed between the capsule unloading container and the base in addition to the interposed position of the seal member. An apparatus for reducing the volume of radioactive metal waste containing a zirconium alloy according to claim 4. 6. One or both of a degassing means for degassing air in the capsule volume reduction space and the capsule unloading container and an inert gas supply means for replacing the air with an inert gas. The apparatus for reducing the volume of radioactive metal waste containing a zirconium alloy according to claim 4 or 5, wherein: