JPH10177094A - Method for sealing up solid waste and solid waste housing body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To integrate disk-shaped compressed compacts made by compressing solid wastes and a housing container, suppress the deterioration with time of the compacts, and improve the stability of the container, by filling the housing container with molten glass and solidifying the compact after making through hole in the compacts in advance and loading them into the housing container in layers. SOLUTION: A metal container 1 loaded with solid wastes c is vertically compressed into a disk shape and is shaped into a compact 2 with a through hole 2a penetrating through the compact 2 in the direction of its thickness. The compacts 2 are loaded into a housing container e in layers. Subsequently, a gap g between the housing container e and the compacts 2 and the through hole 2a is filled with molten glass under a high temperature condition, and the molten glass is cooled and solidified. In a solid waste housing X formed by filling it with glass, the housing container 3 and the compacts 2 are integrated by glass layers G. If radioactive substances adhere to the surface of the compacts, they are taken in the glass layer G and are fixed as they remain confined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sealing solid waste and a solid waste container, and more particularly to a technique for storing high-level shear fragments such as spent fuel rod cladding tubes.

[0002]

2. Description of the Related Art In a spent fuel rod cladding tube, after removing useful substances such as unburned uranium in a fuel reprocessing step or the like, a sheared piece (cut piece) is cut by cutting with a shear and a cutter. If necessary, combustible materials such as fiber waste and plastic waste are removed, and the remaining high-level shear fragments are compressed, loaded into the storage container, and sealed.

FIGS. 4 to 7 show a prior art example in which a sheared piece (cut piece) of a spent fuel rod cladding is sealed. The spent fuel rod cladding tube b of the fuel assembly a shown in FIG. 4 is processed into a sheared piece (cut piece) c as shown in FIG. 5 and then loaded into a plurality of metal containers and compressed. As shown in FIG. 6, it is processed into a disk-shaped compressed body d. As shown in FIG. 7, a plurality of the compressed bodies d are loaded in a stacked state inside a metal storage container e to be sealed, and stored in an environment isolated from a living environment.

[0004]

However, in the case of such a technique, the following problems remain. a) It is necessary to improve the earthquake resistance by fixing the compressed bodies d in a stacked state with, for example, a spring. b) It is necessary to prevent deterioration of the compressed body d due to oxidation or the like by evacuating the inside of the storage container e. c) It is necessary to remove the radioactive substance attached to the compressed body d in advance to suppress the occurrence of the phenomenon that the radioactive substance accumulates in a part of the inside of the storage container e. d) It is necessary to consider the cooling of the heat generating compression body d.

[0005] The present invention is to solve such problems effectively and to achieve the following objects. To integrate the compressed body and the storage container. To suppress the aging of the compressed body and improve the stability. To facilitate the treatment of radioactive material attached to the compact. Improve heat dissipation. To facilitate implementation and enhance practicality. To facilitate storage and storage.

[0006]

Means for Solving the Problems In the case of solid waste,
A technique is adopted in which a metal container loaded with metal waste and loaded with solid waste is compressed into a disk to form a compressed body.The compressed body has a through hole in the thickness direction. You. After the plurality of compressed bodies having through holes are loaded in a stacked state inside the storage container, the gap between the storage container and the compressed body and the through holes are filled with molten glass and solidified to store the compressed body. Seal with container and glass. As a technique for providing a through hole in the compressed body, a ring-shaped metal container having a center hole is prepared in advance, and the solid waste is stored and then compressed. In addition, a method is employed in which a granular or liquid non-compressed material is interposed in a metal rod or pipe, and the metal rod or the non-compressed material is removed after compression molding. Further, as another technique for providing a through hole in the compressed body, a method of forming a through hole in the thickness direction by performing a boring process on the compression molded body is employed. Along with loading a plurality of stacked inside the container and filling and solidifying the molten glass in the gap between the storage container and the compressed body, the storage container and the plurality of compressed bodies are integrated through the solidified glass, If the radioactive substance adheres to the compact, it will be trapped in the solidified glass, and the temperature rise due to the heat generated by the high-level substance will be transmitted uniformly from the solidified glass to the storage container and dissipated .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a solid waste sealing method and a solid waste container according to the present invention will be described.
This will be described with reference to FIGS.

In FIGS. 1 to 3, reference symbol X denotes a solid waste container, 1 denotes a metal container, 2 denotes a compressed body, 2a denotes a through hole, g denotes a gap, and G denotes a glass layer.

[0009] Even in this embodiment, the solid waste c
Is a sheared piece (cut piece) of the spent fuel rod cladding tube b. When compressing a plurality of solid wastes c to reduce the volume (reducing the volume), as shown in FIG. A simple metal container 1 is applied.

The metal container 1 has a cylindrical outer wall 1.
a, a cylindrical inner wall 1b concentrically arranged with respect to the outer wall 1a, a center hole 1c formed in a state surrounded by the inner wall 1b, an outer wall 1a and an inner wall 1b.
And a bottom wall 1d in a state where the center hole 1c is opened in a connected state at a lower portion of the bottom wall, and a state where the center hole 1c is opened in a connected state above the outer side wall 1a and the inner side wall 1b. What has the upper wall 1e and the hollow part 1f in which the solid waste c isolate | separated by each wall and for loading solid waste c is applied.

The working steps up to the sealing of the solid waste will be described below in the order of steps with reference to FIGS.

As described with reference to FIGS. 4 and 5,
The solid waste c formed by cutting the spent fuel rod cladding tube b or the like is loaded into the hollow portion 1e of the metal container 1 and temporarily sealed, as shown in FIG.

The metal container 1 loaded with the solid waste c is
By compressing in the height direction, it becomes a disk shape and, as shown in FIG. 3, is formed into a compressed body 2 having a through hole 2a penetrating in the thickness direction. In this molding step, a metal rod or pipe filled with a granular or liquid non-compressed material is inserted into the center hole 1c of the metal container 1, and the metal container 1 It is necessary to prevent the inner wall 1b from projecting inward so as to close the center hole 1c. Metal rods, pipes, etc. are removed after compression molding,
The compression body 2 is set so as to secure the through hole 2a.

A plurality of the compression bodies 2 having the through holes 2a are loaded in the storage container e in a stacked state.

Thereafter, a gap g between the storage container e and the compressed body 2
The through-hole 2a is filled with molten glass in a high temperature state (for example, borosilicate glass in a molten state) and cooled to solidify the glass. As shown in FIG. The compressed body 2 is sealed with the storage container e and the glass layer G with the glass layer G interposed between the through holes 2a and the like. At the time of filling the molten glass, the molten glass flows through the gap g and the through hole 2a into various places inside the storage container e and into the through hole 2a. The glass layer G is completely covered.

As shown in FIG. 1, a solid waste container X formed by filling glass is in a state where a container e and a plurality of compressed bodies 2 are integrated by solidified glass, that is, a glass layer G. Thus, the plurality of compressed bodies 2 are prevented from moving with respect to the storage container e, and when a radioactive substance is attached to the surface of the compressed body 2, the radioactive substance is taken into the glass layer G. , It is fixed in the trapped state. Therefore, after vitrification, the radioactive substance does not move inside the storage container e, and the radioactive substance becomes 1
It is possible to prevent the phenomenon that the radiation dose is accumulated locally at the location and locally increases the radiation dose at the location.

The decay heat of the radioactive substance contained in the compression body 2 is quickly and quickly transmitted from the compression body 2 to the outer wall of the storage container e via the glass layer G having a high thermal conductivity in the shortest distance in each direction. Therefore, the temperature in each part of the solid waste container X can be reduced, and the occurrence of temperature unevenness can be suppressed.

[Other Embodiments] The solid waste sealing method and the solid waste container according to the present invention include the following techniques. 1) When forming the compression body 2, as shown in the example of FIG. 6, a disk-shaped compression body d without a hole is formed, and a through hole 2a is formed by a press or a drill. 2) The processing waste generated during the above-described drilling is stored in a storage container e.
Vitrification by putting it inside. 3) After the formation of the glass layer G, the remaining gap g or space is filled with an inert gas and sealed.

[0019]

According to the solid waste sealing method and the solid waste container according to the present invention, the following effects can be obtained. (1) A technology in which a through hole is formed in a disk-shaped compressed body in which solid waste is compressed, a plurality of stacked containers are loaded in a storage container, and then molten glass is filled and solidified. The quake resistance can be improved without using a spring or the like. (2) By sealing the compressed body with the glass layer, aging of solid waste can be suppressed, storage and storage in an environment isolated from the living environment can be facilitated, and stability can be improved. . (3) By sealing the compressed body with glass, even if a radioactive substance is attached to the compressed body, the radioactive substance can be confined in the glass layer and the processing can be easily performed. In addition, the movement of the radioactive substance is prevented, so that the phenomenon that the radioactive substance is partially accumulated and the phenomenon that the radiation dose is locally concentrated can be suppressed. (4) By interposing a glass layer having a high thermal conductivity in the gap, the heat radiation of the heat generating compressed body can be enhanced. (5) Even if the solid waste is a high-level spent fuel rod cladding tube, etc., by covering with a glass layer,
Exposure of zirconium and its powder and radioactive materials,
Prevents reactions such as oxidation by direct contact with gas,
Isolation can be secured semipermanently for a long period of time.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an embodiment of a solid waste sealing method and a solid waste container according to the present invention.

FIG. 2 is a front sectional view showing the state of the metal container and the solid waste applied in one embodiment of the solid waste sealing method according to the present invention.

FIG. 3 is a front sectional view of a compressed body applied in an embodiment of the solid waste sealing method according to the present invention.

FIG. 4 is a perspective view showing an example of a fuel assembly and a spent fuel rod cladding tube in a partially cutaway state.

FIG. 5 is a perspective view showing a case where solid waste is a sheared piece of a spent fuel rod cladding tube.

FIG. 6 is a front sectional view showing an example of compression of solid waste.

FIG. 7 is a front sectional view of a state in which a compression body is sealed inside a storage container according to a conventional example.

[Explanation of symbols]

 a Fuel assembly b Spent fuel rod cladding tube c Solid waste (shred, cut pieces) d Compressed body e Storage container X Solid waste storage 1 Metal container 1a Outer side wall 1b Inner side wall 1c Center hole 1d Bottom wall 1e Upper wall 1f Hollow part 2 Compressed body 2a Through hole g Void G Glass layer

Claims (4)

[Claims] 1. A metal container (1) loaded with solid waste (c) is compressed into a disk to form a compressed body (2), and a through hole (2a) in the thickness direction is formed in the compressed body. Is opened, a plurality of compressed bodies having through holes are stacked inside the storage container (e), and the gap (g) between the storage container and the compressed body is filled with molten glass and solidified to seal the compressed body. A method for sealing solid waste. 2. The method for sealing solid waste according to claim 1, wherein the solid waste (c) is stored in a ring-shaped metal container (1) having a center hole. 3. The method for sealing solid waste according to claim 1, wherein a through hole (2a) in a thickness direction is formed in the compression molded body (2). 4. A through-hole (2) compressed in a disk shape in the thickness direction.
A plurality of compacts (2) having a) are loaded in the storage container (e) in a stacked state, and the gap (g) between the storage container and the compact is filled with molten glass and solidified by filling. Solid waste container.