JP2005030981A - Processing method of waste refractory material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the generation quantity of a high level radioactive waste during dismantling a melting furnace. <P>SOLUTION: A laser beam 24 is emitted toward a specific surface 25 of a waste refractory material 21 so that the incidence position is to be slightly on the waste refractory material 21 side from the boundary between glass 23 and the waste refractory material 21. Then a groove gap 27 is formed by evaporation of the waste refractory material 21 on the front side in the beam progressing direction. A crack 28 extending to the beam progressing direction front side is caused from the gap 27 because of thermal stress due to the incidence of the laser beam 24, and so the glass and its neighboring little amount of refractory material surface layer 29 can be selectively removed as high level radioactive waste. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for treating discarded refractory materials.

  The radioactive liquid waste generated from the nuclear facility is vitrified by the waste liquid treatment facility and then stored in the waste storage facility.

  FIG. 2 shows an example of a glass melting furnace constituting a waste liquid treatment facility. This glass melting furnace includes a melting furnace body 2 formed of a refractory material (refractory brick) and having a storage space 1 for molten glass G. (For example, refer to Patent Document 1).

  A raw material supply pipe 3, a waste liquid supply pipe 4, and an exhaust pipe 5 are connected to the upper portion of the melting furnace main body 2 so as to communicate with the storage space 1.

  The melting furnace main body 2 is provided with a pair of main electrodes 6 facing each other at the intermediate portion in the vertical direction of the storage space 1 and a bottom electrode 7 located near the bottom of the storage space 1.

  A lowering nozzle 8 communicating with the storage space 1, an induction heating coil 9 that surrounds the lowering nozzle 8, and an air injection pipe 10 that sends cooling air toward the lowering nozzle 8 are provided at the lower part of the melting furnace body 2. It has been.

  Further, below the melting furnace main body 2, a transport carriage 12 on which a metal solid container (canister) 11 is placed is movably disposed.

  In the glass melting furnace shown in FIG. 2, a predetermined amount of glass raw material is fed from the raw material supply pipe 3 to the storage space 1, and is then melted in the melting furnace main body 2 by an accompanying heating means (not shown). Electricity is passed through the molten glass G between each other or between the main electrode 6 and the bottom electrode 7, and the molten glass G is kept warm so as not to be solidified by Joule heat.

  At this time, since the glass is solidified in the flow-down nozzle 8, the outflow of the molten glass G from the storage space 1 to the outside is suppressed.

  Thereafter, when an additional glass raw material is fed from the raw material supply pipe 3 to the storage space 1, the raw glass melts into the molten glass G, and when the waste liquid is fed from the waste liquid supply pipe 4 to the storage space 1, the waste liquid is Mixed with molten glass G.

  In the vitrification treatment of the waste liquid, the transport carriage 12 on which the solidified container 11 is mounted is moved so that the solidified container 11 is positioned immediately below the flow nozzle 8.

  Next, the induction heating coil 9 is energized to heat the flow-down nozzle 8 and melt the glass in the flow-down nozzle 8 to discharge the molten glass G from the storage space 1 to the solidified body container 11.

When energization of the induction heating coil 9 is interrupted and cooling air is sent from the air injection tube 10 toward the flow-down nozzle 8, the glass is solidified again in the flow-down nozzle 8, and the molten glass G from the storage space 1 to the outside The molten glass G filled in the solidified container 11 is solidified by natural air cooling.
JP 2001-021685 A

  In the glass melting furnace described above, the refractory material used as the constituent material of the melting furnace body 2 is corroded by the high-temperature molten glass G, so that the usable period is about 5 years.

  The waste refractory material generated when the glass melting furnace is disassembled adheres in a solidified state to the glass mixed with the waste liquid, but since this refractory material is hard, only the glass is peeled off and recovered by mechanical means. It is difficult.

  That is, at present, the entire amount of the waste refractory material must be handled as high-level radioactive waste.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to reduce the amount of high-level radioactive waste generated when a melting furnace is dismantled.

  In order to achieve the above object, the waste refractory material processing method according to claim 1, wherein the waste refractory material generated at the time of dismantling the glass melting furnace is irradiated with a laser beam, and the glass adhering to the surface of the refractory material and the refractory material. Cut off the surface layer.

  In the waste refractory material processing method according to claim 2, a YAG laser is used as the laser beam.

  In the waste refractory material processing method according to claim 1, the glass cut by the laser beam and a small amount of the refractory material surface layer portion are selectively handled as high-level radioactive waste, and a large amount of waste refractory material is disposed at low-level radioactive waste. Treat as a thing.

  In the waste refractory material processing method according to claim 2, the glass and the refractory material surface layer portion are efficiently excised with a YAG laser beam.

  According to the waste refractory material processing method of the present invention, the following excellent effects can be obtained.

  (1) Since the glass adhering to the waste refractory material and the surface portion of the refractory material in the vicinity thereof are cut out by the laser beam, only the glass and a small amount of the surface portion of the refractory material can be selectively handled as high-level radioactive waste. .

  (2) Therefore, the remaining waste refractory material can be handled as low-level radioactive waste, and the amount of high-level radioactive waste generated during melting furnace dismantling is reduced.

  (3) Further, by using a YAG laser as the laser beam, it is possible to efficiently remove the glass and the surface portion of the refractory material.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of an embodiment of a disposal refractory material processing method according to the present invention, in which 21 represents a disposal refractory material, and 22 represents a machining head.

  The discarded refractory material 21 is a constituent material of the melting furnace body 2 (see FIG. 2), and is generated when the glass melting furnace is disassembled.

  On one side surface (side surface of the furnace) of the waste refractory material 21, a glass 23 in a state where the waste liquid is mixed and solidified is attached.

  Usually, the size of the refractory material in the glass melting furnace is approximately 300 × 600 × 150 mm.

  The machining head 22 is connected to a YAG laser oscillation device having a continuous rated output of 1.5 kW or more, and emits a laser beam 24.

  When the waste refractory material 21 is processed, the laser beam 24 can be emitted toward a predetermined surface 25 (joint surface of the refractory material) of the waste refractory material 21 intersecting the glass 23 adhesion surface, and the beam incident position is the same as that of the glass 23 and the waste refractory material. The processing head 22 is arranged so as to be about 20 mm from the boundary 26 with the material 21 toward the discarded refractory material 21 side.

  Next, when the laser beam 24 is emitted from the processing head 22 toward the waste refractory material 21, the waste refractory material 21 evaporates in a range of about 20 to 30 mm from the beam incident position on the predetermined surface 25 to the front side in the beam traveling direction. The gap 27 is formed.

  In addition to this, a crack 28 of about 50 mm extending from the gap 27 to the front side in the beam traveling direction is generated by the thermal stress accompanying the incidence on the laser beam 24.

  Further, when the operation of moving the machining head 22 so that the beam incident position is along the boundary 26 and the operation of adjusting the focal position of the laser beam 24 according to the depth of the gap 27, the range of the gap 27 and the crack 28 are obtained. Is enlarged, and the glass 23 and the refractory material surface layer portion 29 in the vicinity thereof are efficiently cut out from the discarded refractory material 21.

  Thereafter, the cut glass 23 and a small amount of the refractory material surface layer portion 29 are vitrified as high-level radioactive waste and stored in a high-level radioactive waste storage facility.

  In addition, a large amount of the discarded refractory material 21 from which the glass 23 and the refractory material surface layer portion 29 are removed is treated as a low-level radioactive waste and then stored in a low-level radioactive waste storage facility.

  Thus, in the waste refractory material processing method shown in FIG. 1, only the glass 23 cut off by the laser beam 24 and a small amount of the refractory material surface layer portion 29 can be selectively handled as high-level radioactive waste. The amount of high-level radioactive waste generated will be reduced.

  It should be noted that the waste refractory material processing method of the present invention is not limited to the above-described embodiment, and it is needless to say that changes can be made without departing from the scope of the present invention.

It is a conceptual diagram which shows an example of embodiment of the disposal refractory material processing method of this invention. It is a conceptual diagram which shows an example of a glass melting furnace.

Explanation of symbols

21 Waste refractory material 23 Glass 24 Laser beam 29 Refractory material surface layer

Claims (2)

  A waste refractory treatment method characterized by irradiating a waste refractory material generated at the time of dismantling a glass melting furnace with a laser beam to cut off the glass adhering to the surface of the refractory material and the surface portion of the refractory material.   The waste refractory material processing method according to claim 1, wherein a YAG laser is used as the laser beam.

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