JPH10307200A - Melting processing method and device for radioactive solid waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new melting processing method and a device thereof which is capable of continuously melting at once such nonmetal materials as mixed state concrete and radioactive metal waste at a low equipment cost and high economy by utilizing cold crucible high frequency induction heating as a heating method. SOLUTION: For melting radioactive metal waste and radioactive solid waste mixed with non-metal material such as concrete by cold crucible high frequency induction heating, an induction coil 2 is wound around a copper made pot 1 of water cooling structure in which radioactive solid waste is thrown, and at its inner surface upper part, a sleeve 10 for heating formed with material heated by induction heating of graphite and the like is arranged to be capable of elevation control at a height not touching the metal melt in the pot. By utilizing the induction heating with the induction coil 2 and heat radiation and heat conduction of the sleeve 10 for heating which is heated by this induction heating, the radioactive solid waste is melted at once.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cold crucible high-frequency induction heating and melting method.
The present invention relates to a radioactive solid waste melting method and apparatus capable of effectively melting and processing a radioactive solid waste in which a nonmetallic substance such as concrete is mixed in the radioactive metal waste while separating the two phases.

[0002]

2. Description of the Related Art A typical prior art for melting and solidifying radioactive waste by high frequency induction heating is disclosed in
Japanese Patent Application Laid-Open No. 19478 (first conventional example) and Japanese Patent Application Laid-Open No. 7-20288 (second conventional example) are known as known techniques.

The first prior art relates to a vitrification method and a vitrification apparatus for radioactive waste, in which a resistance heating element is provided in a high-frequency induction heating melting crucible made of an electrically insulating refractory material so as to be movable up and down. Accordingly, the crucible can be preheated without a preheating auxiliary agent, and the crucible can be prevented from being broken easily at the time of pausing or restarting. This vitrification device uses the induction current generated by the high-frequency current flowing through the induction coil to heat the contents (molten glass) into the crucible,
It has a structure in which the resistance heating element made of silicon carbide, molybdenum silicide, or the like is vertically movable.

The vitrification apparatus vitrifies radioactive waste in the following manner. That is, the heating element is lowered to the lowest position in the crucible, a mixture of calcined radioactive waste and a glass-forming substance is charged into the crucible, and the heating element is induction-heated through a high-frequency current flowing through an induction coil. After the above mixture is appropriately dissolved by heating, the heating element is pulled up and separated from the molten mixture. Next, while the molten mixture is directly induction-heated, the above mixture is further replenished and supplied into a crucible to be melted.Then, the heating ring is energized to melt the glass block closing the outflow nozzle, and the molten mixture is melted. It is caused to flow down into the container through the outflow nozzle.

The second conventional example relates to a glass melting treatment method. In the melting treatment of a glass material or the like, the problem of high-temperature erosion of equipment components and the melting operation temperature set by the heat-resistant temperature of equipment components are considered. The purpose of the present invention is to solve the restriction problem at the same time, and the outline of the configuration is as described below. That is, the object to be melted (a radioactive waste liquid and a glass material) is put into a cold crucible induction melting device, a conductor having a higher melting point than a glass material is inserted into a melting furnace, and a high-frequency current is supplied to the coil to conduct the current. The body is heated to indirectly heat the glass material, the conductor is withdrawn after a portion of the glass material is in a molten state, and subsequently the induction heating by the molten glass material is maintained to bring the whole into a molten state. In this case, as the conductor inserted into the melting furnace, for example, a silicon carbide rod or the like is used.

[0006]

The first prior art relates to a technique for solidifying radioactive waste calcined using a glass-forming substance as a vitreous body, and the second prior art relates to a radioactive waste liquid. Is related to the technology of vitrification in the coexistence of a glass material, and non-metallic materials that have a higher melting point and are different from glass such as concrete are relatively There is a problem that is difficult to apply to an apparatus for batch melting radioactive metal waste mixed in a large amount. That is, in both conventional examples, the object to be treated is clearly different from that of the present invention in that the glass-forming substance is an indispensable element of the object to be treated, and the furnace type is an electrically insulating refractory brick. Radioactive metal waste containing relatively large amounts of non-metallic substances such as concrete is melted by cold crucible high-frequency induction heating, for example, using silicon carbide rods for auxiliary heating in the furnace used or cold crucible high-frequency induction heating The present invention is markedly different from the present invention in features, objects, methods, and basic structures.

The first prior art is a processing method in which a rod-shaped resistance heating element is inserted into the content (molten glass), and is heated by resistance heating and is pulled up while being melted. It is impossible to simultaneously melt the radioactive metal waste and nonmetallic material such as concrete in a state by such a resistance heating element. Also, the second
Conventional examples, as a conductor to be inserted into the melting furnace, for example,
Although silicon carbide rods or the like are used, in the case of radioactive metal waste containing a relatively large amount of nonmetallic material such as concrete, slag components such as concrete are present not in the center of the crucible but in the vicinity of the crucible inner wall. However, it is needless to say that an effective heating for batch melting cannot be expected in the case where such a rod-shaped conductor is inserted into the center portion.

The present invention still proposes a technique for effectively collectively melting radioactive metal waste containing a relatively large amount of a nonmetallic substance such as concrete by cold crucible high-frequency induction heating as described above. Therefore, the object of the present invention is to reduce non-metallic substances such as concrete and radioactive metal waste in a mixed state by using cold crucible high-frequency induction heating as a main heating method. An object of the present invention is to provide a novel melting treatment method capable of continuously and collectively melting under equipment cost and high economic efficiency, and an apparatus to be used in the method.

[0009]

The present invention has the following configuration to achieve the above object. That is, when the radioactive solid waste obtained by mixing non-metallic substances such as concrete in the radioactive metal waste is melted by cold crucible high-frequency induction heating, the radioactive solid waste is charged with copper. A heating sleeve, which is formed in a cylindrical body by a substance that generates heat by induction heating such as graphite, is arranged at the upper part of the inner surface of the crucible so as to be adjustable up and down to a height that does not come into contact with the molten metal, and is heated by induction heating and the induction heating A method for melting radioactive solid waste, characterized in that the radioactive solid waste is melted by utilizing the heat radiation and heat conduction of the heating sleeve.

According to the first aspect of the present invention, the non-metallic material such as concrete, which is difficult to melt only by the cold crucible high frequency induction heating and melting, can be melted only by providing the heating sleeve, whereby the radioactive solid waste can be melted. , The production of the solidified and solidified body is easy.

The invention according to claim 2 is characterized in that when the radioactive solid waste obtained by mixing non-metallic substances such as concrete into the radioactive metal waste is melted by cold crucible high frequency induction heating, the radioactive solid waste is charged. A heating sleeve formed in a cylindrical body by a substance that generates heat by induction heating such as graphite is arranged to be able to move up and down over the entire inner surface of the copper crucible to be heated, and heat radiation of the heating sleeve heated by induction heating is performed. And melting the radioactive solid waste by utilizing heat conduction.

According to the second aspect of the present invention, since the heating sleeve can be arranged over the entire length of the inner surface of the copper crucible, the radioactive solid waste composed of the radioactive metal waste and the nonmetallic substance can be collectively collected. Can be melted. in this case,
The heating sleeve can have a role of protecting the inner surface of the copper crucible, and the safety of the crucible is enhanced.

The invention according to claim 3 is characterized in that when the radioactive solid waste obtained by mixing non-metallic substances such as concrete into radioactive metal waste is melted by cold crucible high-frequency induction heating, the radioactive solid waste is charged. On the upper part of the copper crucible to be placed, a heating upper heater formed on the board body by a substance that generates heat by induction heating such as graphite is disposed so as to be openable and closable so that it can be fitted to the top opening of the copper crucible. A method for melting radioactive solid waste, characterized in that radioactive solid waste is melted using heat radiation of a heating upper heater heated by the induction heating.

According to the third aspect of the present invention, the melting ability of the upper heating heater for non-metallic substances such as concrete is slightly lower than that of the heating sleeve. Compared to this, there is a feature that the degree of wear is small and that it is economically advantageous.

The invention according to claim 4 is a melting treatment apparatus for melting a radioactive solid waste obtained by mixing radioactive metal waste with a nonmetallic substance such as concrete by cold crucible high-frequency induction heating. A water-cooled copper crucible into which solid waste is charged, an induction coil wound around the outer periphery of the copper crucible and supplied with high-frequency power, and a material that generates heat by induction heating, such as graphite, is applied to the copper crucible. A heating sleeve formed in a relatively short cylindrical body and fitted to be movable up and down along the upper part of the inner surface of the copper crucible, a lifting drive device for raising and lowering the heating sleeve, and controlling the lifting drive device And a control means for raising and lowering the heating sleeve to a height not in contact with the molten metal in the copper crucible.

According to the fourth aspect of the present invention, the heating sleeve for the cylindrical body, the lifting / lowering drive device, and the control means may be attached to the conventional cold crucible high-frequency induction heating furnace. The operation of raising and lowering the sleeve is also easy, and the solidification of the radioactive solid waste can be performed at low cost.

The invention according to claim 5 is a melting treatment apparatus for melting radioactive solid waste obtained by mixing non-metallic substances such as concrete into radioactive metal waste by cold crucible high-frequency induction heating. A water-cooled copper crucible into which solid waste is charged, an induction coil wound around the outer periphery of the copper crucible and supplied with high-frequency power, and the copper crucible formed of a substance that generates heat by an induction heating action such as graphite. A heating sleeve formed in a substantially equal length cylindrical body and fitted to be movable up and down along the substantially entire length of the inner surface of the copper crucible; an elevating drive device for elevating and lowering the heating sleeve; and an elevating drive device. And a control means for controlling the heating sleeve to move up and down.

According to the fifth aspect of the invention, the advantage is that the structure is simple, the operation of raising and lowering the heating sleeve can be easily performed, and the solidification treatment of the radioactive solid waste can be performed at low cost. This is the same as the invention of item 4. In the present invention, the operation of raising and lowering the heating sleeve is not required during the melting operation, so the operation is simple, and even if the thickness of the heating sleeve that reacts with the radioactive metal waste during melting is reduced, for example, The amount of solid solution of carbon in iron in the case of graphite is 5
%, The rate of decrease is slow and can sufficiently withstand long-term use, and does not significantly affect the increase in the cost of the apparatus even if it is considered as a consumable.

The invention of claim 6 is the same as the above-described claim 4.
Or in the apparatus for melting radioactive solid waste according to 5, wherein a slag discharge port is provided at an upper part of the peripheral body of the copper crucible, and one or more slags are discharged from the discharge port slag to the peripheral part of the heating sleeve. A plurality of slag discharge holes are provided, and melting is performed while discharging slag components generated when performing melting by cold crucible high-frequency induction heating.

According to the sixth aspect of the present invention, since the slag component generated during the melting is discharged while the operation is continued, the molten solidified material is continuously drawn downward to form a long slag component. It has the characteristic that a solid can be manufactured rationally.

The invention according to claim 7 is a melting treatment apparatus for melting radioactive solid waste obtained by mixing non-metallic substances such as concrete into radioactive metal waste by cold crucible high frequency induction heating. A water-cooled copper crucible into which solid waste is charged, an induction coil wound around the outer periphery of the copper crucible and supplied with high-frequency power, and a material that generates heat by an induction heating action such as graphite. A heating upper heater formed on a board body that can be fitted to the top opening and disposed above the copper crucible so as to be capable of opening and closing the top opening, an opening / closing drive device for opening and closing the heating upper heater, Control means for controlling the opening / closing drive device to fit the heating upper heater to the top opening of the copper crucible.

According to the seventh aspect of the present invention, the upper heater for heating, the opening / closing drive device and the control means may be attached to the conventional cold crucible high-frequency induction heating furnace, and the structure is simple and the consumption is low. Since there are no members, it is advantageous in terms of low manufacturing cost and operating economy.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be sequentially described below with reference to the accompanying drawings. FIG.
FIG. 4 to FIG. 4 are longitudinal cross-sectional overall structural views of each of the cold crucible high-frequency induction melting furnaces according to the first to fourth embodiments of the present invention.

First, in FIG. 1, a cold crucible high frequency induction melting furnace (hereinafter, abbreviated as a melting furnace) is shown.
Comprises a copper crucible 1, a heating induction coil 2, a heating sleeve 10, a lifting drive device 16, and a control means 17 as main components. The copper crucible 1 is formed in, for example, a cylindrical body that is long in the longitudinal direction of a structure divided in the circumferential direction, and has a water-cooling structure including a water-cooling jacket 3 on a circumferential body. The induction coil 2 is wound around the outer periphery of the copper crucible 1 and connected to a high-frequency power supply (oscillator) (not shown). The heating sleeve 10 is made of, for example, graphite, and has a cylindrical length or an upside-down cup shape whose axis length is shorter and shorter than that of the copper crucible 1 and whose outer diameter is slightly smaller than the inner diameter of the crucible 1. It is formed in a topped cylinder. The heating sleeve 10 is fitted in the copper crucible 1 and provided so as to be able to slide up and down along the inner surface of the crucible 1. The material of the heating sleeve 10 is a material that has a higher melting point than non-metallic materials such as concrete and that generates heat by the induction heating action of the induction coil 2. (SiC), molybdenum silicide and the like are also used.

The heating sleeve 10 is connected to an elevating drive device 16 realized by an actuator such as an electric motor, and is moved up and down along the upper part of the inner surface of the copper crucible 1 by the operation of the drive device 16 so that the heating sleeve 10 is made of copper. The height is adjusted so as to be fixed at a position immediately above the molten metal 11 formed in the crucible 1. The lifting / lowering drive device 16 includes the control unit 1
7 to control the stroke adjustment and the switching of the vertical direction.

In the melting furnace having such a structure, the bottom of the copper crucible 1 is provided with a furnace bottom 4 which is removably fitted, and is provided so as to surround the furnace bottom 4. Is detachably separated from the copper crucible 1 at a separation portion 5. Reference numeral 7 denotes a cooling water inlet. The cooling water introduced from the cooling water cools the lower furnace body 6 and the copper crucible 1 and is discharged from a cooling water outlet 8. An ingot elevating device 9 is provided in association with the furnace bottom 4, and is used for taking out a solidified body after solidification. In the figure, reference numeral 12 denotes a metal-assisting slab, which is provided on the furnace bottom 4 to actively promote melting of the bottom portion of the filled radioactive solid waste. Therefore, it is possible to reduce the number of skulls 13 formed below the molten metal 11 generated by dissolving the metal waste.

Next, a method of melting and solidifying radioactive solid waste by the melting furnace having the above-described configuration will be described below. In this case, as the radioactive solid waste, a radioactive metal waste mixed with a nonmetallic substance such as concrete is applied. After the radioactive solid waste is filled in the copper crucible 1 and the crucible 1 is cooled with water, the induction coil 2 is energized to melt the radioactive solid waste with Joule heat. It becomes 11.
When melted in this manner, non-metallic substances such as concrete having a low specific gravity gradually float upward. Normally, the frequency and power supply capacity of the induction coil 2 are set to values that optimally dissolve the metal. However, at this frequency and power supply capacity, non-metallic substances such as concrete often do not dissolve effectively.

As a means for solving such a problem, as shown in a first comparative example device shown in FIG. 5, separate induction coils 2 corresponding to the upper non-metal component portion and the lower metal portion are provided.
A method is conceivable in which A and 2B are provided to supply power with different frequencies. However, arranging coils of a plurality of frequencies has a problem that a plurality of types of power supply devices are required and the cost is increased.

Further, as in the second comparative example shown in FIG. 6, the lower metal part is melted by Joule heat by the induction coil 2 and the upper non-metallic part is melted by plasma heat by the plasma torch 20. A method is also conceivable. However, in such an apparatus, the copper crucible 1 is not affected by the plasma arc.
It is not preferable from the viewpoint of safety in consideration of the possibility of damaging the device.

In contrast to these comparative examples, in the melting furnace of the first embodiment, in the melting furnace of the first embodiment, a high-frequency induction made of graphite or the like whose height can be adjusted by an elevating drive device 16 is provided above the inner surface of the copper crucible 1. A heating sleeve 10 made of a melting point material is arranged, and electricity is supplied to a single system of the induction coil 2.
The non-metallic portion such as concrete is heated and melted by the heat radiation and heat conduction of the sleeve 10 which has been heated to red. In this case, the heating sleeve 1
The height is adjusted so that 0 is a level that does not make contact with the molten metal 11. This is because when the material of the heating sleeve 10 is graphite and the molten metal 11 is, for example, an iron component,
This is because there is a problem in that the heating sleeve 10 reacts when contacted with each other and the wall thickness of the heating sleeve 10 is reduced.

In this manner, the lower metal portion is melted by Joule heat generated by the induction coil 2, and the upper non-metallic component such as concrete is melted by heat conduction and heat radiation of the glowing sleeve 10. The melting furnace according to the first embodiment has advantages in both equipment cost and safety. In addition, since the bottom of the molten metal 11 may be insufficiently melted, it is preferable to arrange the auxiliary slab 12 to promote the melting of the bottom of the molten metal 11 as described above. is there. When the melting is completed, the induction coil 2 is turned off and the molten metal 1
1. Cool and solidify the non-metallic components. The ingot after solidification is taken out of the copper crucible 1 by operating the ingot elevating device 9 up and down.

FIG. 2 shows a melting furnace according to a second embodiment of the present invention. In this embodiment, similar to the first embodiment shown in FIG. 1, corresponding members are denoted by the same reference numerals, and detailed description thereof will be omitted. A feature of this melting furnace is that a heating upper heater 19 is provided in place of the heating sleeve 10. The upper heating heater 19 is made of a substance that generates heat by induction heating, such as graphite, like the heating sleeve 10, and can be fitted in the top opening of the copper crucible 1 without sealing, for example, a disk. Formed. The heating upper heater 19 is disposed on the upper part of the copper crucible 1 so as to be openable and closable so as to close or open the top opening, and includes, for example, an opening / closing drive device 18 including a swing arm, an electric motor, a rack, and a pinion. Opening and closing control is performed by the control unit 17 that controls the driving device 18.

Such a melting furnace is provided with the above-described upper heater 19.
Is fitted to the top opening of the copper crucible 1, is energized to the induction coil 2, and the upper heating heater 19 is heated by induction heating to become reddish. A non-metallic component such as concrete located immediately above the molten metal 11 can be heated and melted, and the metal portion can be heated and melted by the induction coil 2.
The upper heating heater 19 is arranged at a height that does not come into contact with the molten metal 11 during the melting operation, and is made of copper so as not to hinder these operations when filling the target waste or taking out the ingot. The crucible 1 is shifted to a position shown in FIG.

The melting furnace according to the second embodiment is slightly lower in melting ability with respect to non-metallic components such as concrete, that is, hardly meltable substances, as compared with the melting furnace having the heating sleeve 10. Since the operation of raising and lowering the sleeve is omitted, the structure is simplified, the equipment cost is reduced, and there is no need to consider the degree of wear of the sleeve.

FIG. 3 shows a melting furnace according to a third embodiment of the present invention. In this embodiment, similar to the first embodiment shown in FIG. 1, corresponding members are denoted by the same reference numerals, and detailed description thereof will be omitted. The feature of this melting furnace is that the shape of the heating sleeve 10 is slightly different from that of the first embodiment. That is, while the heating sleeve 10 according to the first embodiment is short in the axial length, the heating sleeve 10 according to the present embodiment is formed as a long cylindrical body having substantially the same length as the copper crucible 1. The feature is that it does. Then, the heating sleeve 10 of the long cylindrical body is connected to the copper crucible 1.
Is fitted to the copper crucible 1 so as to be able to move up and down along substantially the entire length of the inner surface of the copper crucible.

In the melting furnace according to the third embodiment, the heating sleeve 10 is fitted over the entire inner surface of the copper crucible 1 from the upper surface of the auxiliary slab 12 as shown in the drawing. By energizing the induction coil 2, the sleeve 10 is heated and glows red. Due to the radiant heat and heat conduction of the red heating sleeve 10, the lower metal part and the upper non-metal part such as concrete, which gradually separate in the melting process, can be melted simultaneously. In this case, the heating sleeve 1
0 reacts with the molten metal 11 to reduce the thickness of the sleeve 10. However, the sleeve 10 is considered as a consumable item, and is taken out of the copper crucible 1 and replaced with a spare part by the lifting / lowering drive device 16 and the control means 17 at the time of melting stop. . In the case of graphite, since the solid solution amount of carbon in iron as a metal part is about 5%, a corresponding decrease in wall thickness is expected, but the loss is not so great that it must be replaced in a short time.

In the melting furnace according to the third embodiment, since the heating sleeve 10 is disposed over substantially the entire inner surface of the copper crucible 1, there is no extra operation such as raising and lowering of the sleeve 10 during the melting operation. In addition, batch melting of radioactive solid waste consisting of a metal portion and a non-metal portion such as concrete can be easily performed. Further, the heating sleeve 10 can have a role of protecting the inner surface of the copper crucible 1, and there is an advantage that the long life of the copper crucible 1 is achieved and the safety is improved.

FIG. 4 shows a melting furnace according to a fourth embodiment of the present invention. In this embodiment, similar to the first embodiment shown in FIG. 1 and the third embodiment shown in FIG. 3, corresponding members are denoted by the same reference numerals.
A feature of the configuration of this melting furnace is that a slag discharge port 14 is provided at the upper part of the peripheral body of the copper crucible 1 and the slag discharge port 1 is provided at the peripheral part of the heating sleeve 10.
4 is provided with one or a plurality of slag discharge holes 15 for discharging the slag from the slag 4. By this configuration, the radioactive metal waste containing a considerable amount of a nonmetallic substance such as concrete can be removed. Melting can be performed while discharging slag components generated during melting by induction heating.

In the melting furnace according to the fourth embodiment,
When the radioactive metal waste is melted, a slag component is generated. Since the specific gravity of the slag component is smaller than that of the metal component, the slag component floats on the molten metal 11 and is separated into two layers. When the radioactive metal waste is continuously charged and melted, the slag component accumulates on the molten metal 11 and hinders the continuous melting, but the slag discharge port 14 and the slag discharge hole 1
Since the slag component 5 is provided, the generated slag component can be continuously melted while being sequentially discharged from the copper crucible 1 by operating the ingot lifting device 9 to push up and down the furnace bottom 4. By doing so, the molten solidified body can be continuously pulled out, so that a long solidified body can be obtained.

The melting furnace according to the fourth embodiment can discharge the slag component while melting, and can continuously pull out the molten solidified material downward, thereby obtaining a long solidified material. Can be

[0041]

The present invention is embodied in the form described above and has the following effects. That is,
According to the first and fourth aspects of the present invention, non-metallic materials such as concrete, which are difficult to melt only by cold crucible high frequency induction heating and melting, can be melted only by adding a heating sleeve provided so as to be able to move up and down. Of solidified radioactive solid waste can be easily manufactured. In addition, compared to the conventional induction heating method, in which multiple power supplies with different frequencies and power supply capacities are combined to melt nonmetallic substances such as metal and concrete at once, equipment costs are significantly lower and economical. Is excellent.

According to the second and fifth aspects of the present invention, since the heating sleeve is disposed over the entire inner surface of the copper crucible, the heating sleeve is made of a nonmetallic material such as metal and concrete without raising and lowering the sleeve during melting. Radioactive solid waste can be melted at once. Further, the heating sleeve can have a role of protecting the inner surface of the crucible, and the safety of the crucible is improved.

According to the third and seventh aspects of the present invention, since the upper heating heater is disposed at the top opening of the copper crucible so as to be openable and closable, the melting ability for non-metallic substances such as concrete is provided by the heating sleeve. However, the operation of raising and lowering the sleeve during melting is eliminated, so that the structure and operation are simplified, and the equipment cost is reduced, and the number of consumable members is reduced and the economy is excellent.

According to the invention of claim 6, since the slag component generated during melting can be discharged during the melting operation, the molten solid can be continuously drawn downward to produce a long solidified body. It is.

[Brief description of the drawings]

FIG. 1 is an overall structural view showing a longitudinal section of a cold crucible high frequency induction melting furnace according to a first embodiment of the present invention.

FIG. 2 is an overall structural view showing a longitudinal section of a cold crucible high frequency induction melting furnace according to a second embodiment of the present invention.

FIG. 3 is an overall structural view showing a longitudinal section of a cold crucible high frequency induction melting furnace according to a third embodiment of the present invention.

FIG. 4 is an overall structural view showing a longitudinal section of a cold crucible high frequency induction melting furnace according to a fourth embodiment of the present invention.

FIG. 5 is an overall structural view showing a longitudinal section of a cold crucible high frequency induction melting furnace as a first comparative example.

FIG. 6 is an overall structural view showing a longitudinal section of a cold crucible high frequency induction melting furnace as a second comparative example.

[Explanation of symbols]

1. Copper crucible, 2. Induction coil, 3.
... water cooling jacket, 4 ... furnace bottom, 5 ... separation section, 6 ... lower furnace body, 7 ... cooling water inlet,
8 Cooling water outlet 9 Ingot elevating device 10 Heating sleeve 11 Metal melt 1
2 slab for auxiliary melting, 13 skull, 14 slag discharge port, 15 slag discharge hole, 16 lifting drive device, 17 control means, 18 opening / closing drive device, 19 heating top heater,

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuhiko Kusamichi 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Inside Kobe Research Institute, Kobe Steel Ltd. (72) Inventor Koichi Sakamoto Nishi-ku, Kobe City, Hyogo Prefecture 1-5-5 Takatsukadai Kobe Steel, Ltd. Kobe Research Institute

Claims (7)

[Claims] When melting a radioactive solid waste obtained by mixing a nonmetallic substance such as concrete into a radioactive metal waste by cold crucible high-frequency induction heating, a copper crucible into which the radioactive solid waste is charged is placed on an upper portion of an inner surface of the copper crucible. ,
A heating sleeve formed in a cylindrical body by a substance that generates heat by an induction heating action such as graphite is arranged so as to be vertically movable at a height that does not come into contact with the molten metal, and the heating sleeve is heated by the induction heating and the induction heating. A method for melting radioactive solid waste, comprising melting radioactive solid waste using heat radiation and heat conduction. 2. When melting a radioactive solid waste obtained by mixing a nonmetallic substance such as concrete into a radioactive metal waste by cold crucible high-frequency induction heating, the entire length of the inner surface of the copper crucible into which the radioactive solid waste is charged is increased. Along the way, a heating sleeve formed in a tubular body by a substance that generates heat by induction heating such as graphite is arranged so as to be able to move up and down, and utilizing heat radiation and heat conduction of the heating sleeve heated by induction heating. A method for melting radioactive solid waste, comprising melting radioactive solid waste. 3. When melting a radioactive solid waste obtained by mixing a nonmetallic substance such as concrete into a radioactive metal waste by cold crucible high-frequency induction heating, the radioactive solid waste is placed above a copper crucible into which the radioactive solid waste is charged. , A heating upper surface heater formed of a substance that generates heat by an induction heating effect such as graphite or the like is disposed so as to be openable and closable so as to fit into a top opening of a copper crucible, and is heated by the induction heating and the induction heating. A method for melting radioactive solid waste, wherein the radioactive solid waste is melted by utilizing the heat radiation of the upper surface heater. 4. A melting treatment apparatus for melting radioactive solid waste obtained by mixing non-metallic substances such as concrete into radioactive metal waste by cold crucible high frequency induction heating, wherein said radioactive solid waste is charged. A water-cooled copper crucible, an induction coil wound around the outer periphery of the copper crucible and supplied with high-frequency power, and a tube that is short and shorter than the copper crucible by a substance that generates heat by induction heating such as graphite. A heating sleeve formed and fitted to be movable up and down along the upper part of the inner surface inside the copper crucible, an elevating drive device for elevating the heating sleeve, and controlling the elevating drive device to control the heating sleeve A control unit for adjusting the height of the copper crucible so as not to come into contact with the molten metal in the copper crucible. 5. A melting treatment apparatus for melting radioactive solid waste obtained by mixing non-metallic substances such as concrete into radioactive metal waste by cold crucible high-frequency induction heating, wherein the radioactive solid waste is charged. A copper crucible having a water-cooled structure, an induction coil wound around the outer periphery of the copper crucible and supplied with high-frequency power, and a tubular body substantially equal in length to the copper crucible formed of a substance that generates heat by induction heating such as graphite. A heating sleeve formed and fitted to be movable up and down along the substantially entire length of the inner surface of the copper crucible; an elevating drive device for elevating the heating sleeve; and controlling the elevating drive device to control the heating sleeve. And a control means for adjusting the height of the radioactive solid waste. 6. A slag discharge port is provided in an upper part of a peripheral body of a copper crucible, and one or a plurality of slag discharge holes for discharging slag from the discharge port slag are provided in a peripheral body part of a heating sleeve. The radioactive solid waste melting treatment apparatus according to claim 4 or 5, wherein the melting is performed while discharging a slag component generated when the melting is performed by the crucible high-frequency induction heating. 7. A melting treatment apparatus for melting radioactive solid waste obtained by mixing non-metallic substances such as concrete into radioactive metal waste by cold crucible high-frequency induction heating, wherein the radioactive solid waste is charged. A copper crucible having a water-cooled structure, an induction coil wound around the outer periphery of the copper crucible and supplied with high-frequency power, and a material that generates heat by induction heating such as graphite can be fitted to the top opening of the copper crucible. A heating upper heater formed on the board body and disposed on the upper part of the copper crucible so as to be capable of opening and closing the top opening;
An opening and closing drive for opening and closing the heating upper heater;
Control means for controlling the opening / closing drive device to fit the heating upper heater to the top opening of the copper crucible, and a radioactive solid waste melting treatment apparatus.