Joule furnace for treating radioactive waste liquid

Abstract

The utility model relates to the field of radioactive waste liquid treatment devices, and discloses a Joule furnace for treating radioactive waste liquid, which comprises a smelting furnace body, a smelting furnace cavity is arranged in the smelting furnace body, and the top of the smelting furnace body is connected with a feeding pipeline and an exhaust pipe which are communicated with the smelting furnace cavity. A stirring device, a liquid level measuring device and a temperature measuring device are installed in the smelting furnace cavity, heating devices are arranged in the circumferential direction of the smelting furnace cavity, and the bottom of the smelting furnace cavity communicates with the discharging channel. The radioactive waste liquid heating furnace has the beneficial effects that the state of radioactive waste liquid in the furnace is easy to judge, the radioactive waste liquid is uniformly heated, the heat insulation effect is good, radioactivity can be effectively isolated, and the heating temperature and heating time at different positions can be flexibly adjusted.

Description

Technical Field

[0001] The utility model relates to the field of radioactive waste liquid treatment devices, in particular to a Joule furnace for treating radioactive waste liquid. Background Technique

[0002] Radioactive waste liquid is a liquid with high-level radioactivity generated during the reprocessing of nuclear fuel. It contains more than 97% of the total fission products in irradiated nuclear fuel and has characteristics such as high radioactive concentration, high heat release rate, and strong corrosiveness. Once radioactive waste liquid enters the natural environment, it will cause extremely serious harm. Therefore, strict management and proper treatment of radioactive waste liquid are required. The radioactive waste liquid vitrification process is to calcine and concentrate the radioactive waste liquid, evaporate the internal moisture of the waste liquid, convert the salts into oxides, and then add glass additives and melt and mix them together. After cooling, a glass solidification body is formed and then encapsulated and landfilled. Since the glass solidification body has good chemical stability and mechanical stability, radioactive waste liquid vitrification is the most practical waste liquid treatment process in China at present.

[0003] The Joule furnace is the core equipment in the method of radioactive waste liquid vitrification and is the main place for the evaporation, decomposition, and calcination of radioactive waste liquid. When the radioactive waste liquid is calcined, melted, and mixed in the Joule furnace, it is in a closed state. Therefore, it is only possible to judge the treatment duration of the radioactive waste liquid in the furnace, the interval duration for continuously adding radioactive waste liquid, and the addition amount based on experience, with a large error. Inaccurate judgment results will also cause various problems, such as too much or too little radioactive waste liquid being processed in the furnace, too high or too low heating temperature, poor quality of the formed glass solidification body, and damage to the overall equipment, shortening the service life. Moreover, due to the strong radioactivity of the radioactive waste liquid and the need to maintain a temperature of 950°C - 1000°C during calcination, the temperature is very high. Therefore, there are also high requirements for the shell heat preservation and radiation isolation of the Joule furnace. In addition, the radioactive waste liquid also has relatively high requirements for the heating device, and it is necessary to adjust the heating temperature in a timely manner according to different states of calcination or melting and mixing. Moreover, the timing of heating required at different positions in the Joule furnace is different, and it is necessary to flexibly adjust the heating temperature and heating timing at different positions. Finally, the radioactive waste liquid needs to be evenly heated during calcination. Content of the Utility Model

[0004] In order to overcome the problems in the above background technique, the utility model provides a Joule furnace for treating radioactive waste liquid. By using different measuring devices in cooperation, the temperature and liquid level of the radioactive waste liquid in the furnace can be detected, and the temperature and state of the radioactive waste liquid can be adaptively adjusted through electrode devices at different positions. It has the beneficial effects of being easy to judge the state of the radioactive waste liquid in the furnace, the radioactive waste liquid being evenly heated, good heat preservation and heat insulation effects, being able to effectively isolate radioactivity, and being able to flexibly adjust the heating temperature and heating timing at different positions.

[0005] The technical solution of the utility model is as follows:

[0006] A Joule furnace for treating radioactive waste liquid includes a furnace body. A furnace cavity is provided inside the furnace body. The top of the furnace body is connected with a feed pipe and an exhaust pipe that communicate with the furnace cavity. A stirring device, a liquid level measuring device, and a temperature measuring device are installed in the furnace cavity, and a heating device is arranged circumferentially. The bottom communicates with a discharge channel.

[0007] Compared with the prior art, the beneficial effects of this technical solution are as follows:

[0008] The radioactive waste liquid enters the furnace cavity through the feed pipe. The heating device fully calcines the radioactive waste liquid to decompose, concentrate, and evaporate it. Then, glass additives are added through the feed pipe and melted and mixed together. After processing, it is discharged from the discharge channel. The gas generated during the calcination process is discharged from the exhaust pipe. The setting of the stirring device makes the radioactive waste liquid evenly heated and can be fully and evenly mixed with the glass liquid. The liquid level measuring device can monitor the liquid level height in the furnace cavity in real time, adjust the feeding amount according to the measurement result, and keep the radioactive waste liquid in the furnace cavity within the designed working range. The temperature measuring device can monitor the temperature in the furnace cavity in real time, adjust the feeding amount in time according to the measurement result, and control the switch of the heating device to keep the temperature of the radioactive waste liquid within the designed working range. The combined use of the liquid level measuring device and the temperature measuring device improves the accuracy of judging the state of the radioactive waste liquid. It can not only judge the treatment time of the radioactive waste liquid in the furnace, the interval time and the addition amount of continuously adding radioactive waste liquid according to the measurement result, but also add glass additives according to the measurement result. Therefore, the Joule furnace designed in this technical solution integrates various detection devices and heating devices, and has the beneficial effects of being easy to judge the state of the radioactive waste liquid in the furnace, evenly heating the radioactive waste liquid, good heat preservation and heat insulation effects, being able to effectively isolate radioactivity, and being able to flexibly adjust the heating temperature and heating time at different positions.

[0009] Preferably, the shell of the furnace body includes an outer shell and a furnace lining fixed inside the outer shell. The furnace cavity is arranged inside the furnace lining. The outer shell is made of metal material. The furnace lining includes an outer layer furnace lining, a middle layer furnace lining, and an inner layer furnace lining. The outer layer furnace lining is made of ceramic fiber board, the middle layer furnace lining is made of clay insulation brick, and the inner layer furnace lining is divided into an upper furnace lining and a lower furnace lining. The dividing line between the upper furnace lining and the lower furnace lining is the highest liquid level line in the furnace. The upper furnace lining is made of zircon corundum, the lower furnace lining is made of clay brick and chrome corundum, and the chrome corundum layer is located inside the clay brick layer.

[0010] Preferably, the stirring device includes a flexible hose. The flexible hose is fixedly connected to a spray pipe downward. The spray pipe extends into the radioactive waste liquid from an auxiliary support at the top of the furnace. Its bottom is inclined. Compressed air is passed through the flexible hose.

[0011] Preferably, the liquid level measuring device includes a hose, which is fixedly connected to a liquid level pipe downward. The liquid level pipe extends into the radioactive waste liquid from an auxiliary support on the furnace top, and a pipe cover is fixedly connected to its bottom. The top of the hose is connected to a pressure measuring device.

[0012] Preferably, the temperature measuring device includes a number of thermocouples arranged at different heights. A protective tube is sleeved outside the thermocouple. The bottom of the protective tube extends into the radioactive waste liquid from an auxiliary support on the furnace top, and the temperature measuring part of the thermocouple is located at the bottom of the protective tube.

[0013] Further preferably, the auxiliary support includes a connecting pipe vertically passing through the furnace top. The connecting pipe is fixedly connected to the furnace top. A flange for installing various components is fixed at the top of the connecting pipe, and an insulating ceramic layer is provided in the middle of the flange.

[0014] Further preferably, the heating device includes a number of pairs of electrode devices symmetrically arranged in the melting furnace body. Each electrode device includes an electrode head extending into the radioactive waste liquid. The other side of the electrode head is fixedly connected to a horizontally arranged electrode shaft tube. The tail end of the electrode shaft tube penetrates through the side wall of the melting furnace body and is connected to an electrode switch.

[0015] Further preferably, there are 4 pairs of the electrode devices, including a pair of main electrodes below the lowest liquid level line, a pair of secondary electrodes below the main electrodes, a pair of freeze-thaw electrodes at the bottom of the melting furnace cavity, and a pair of discharge electrodes at the discharge port.

[0016] Further preferably, a cooling ring channel in which a fluid medium can circulate is provided in the electrode head and the electrode shaft tube. The outlet of the cooling ring channel is connected to a silencer; a thermocouple is also provided in the electrode shaft tube. A protective tube is sleeved outside the thermocouple, and its temperature measuring part is located in the electrode head.

[0017] Further preferably, an insulating ceramic layer is circumferentially provided at the connection between the electrode shaft tube and the outer shell of the melting furnace body, and it is fixed on the outer wall of the melting furnace body through an electrode support. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be described with reference to the drawings, in which:

[0019] Figure 1 is a schematic structural diagram of the whole of the present invention;

[0020] Figure 2 is a schematic structural diagram of the stirring device of the present invention;

[0021] Figure 3 is a schematic structural diagram of the liquid level measuring device of the present invention;

[0022] Figure 4 is a schematic structural diagram of the temperature measuring device of the present invention;

[0023] Figure 5 This is a schematic structural diagram of the electrode device of the present utility model.

[0024] Reference numerals: furnace cavity 11, feed pipe 12, exhaust pipe 13, discharge channel 14, stirring device 2, hose 21, nozzle 22, liquid level measuring device 3, liquid level pipe 31, pipe cover 32, temperature measuring device 4, thermocouple 41, protection tube 42, signal box 43, outer shell 51, outer furnace lining 52, middle furnace lining 53, inner furnace lining 54, upper furnace lining 541, lower furnace lining 542, auxiliary support 6, connecting pipe 61, installation channel 62, flange 63, electrode support 70, electrode head 71, electrode shaft tube 72, main electrode 73, auxiliary electrode 74, freeze-thaw electrode 75, discharge electrode 76, cooling loop 77, inlet flange 78, silencer 79, insulating ceramic layer 8. Specific embodiments

[0025] In order to make the objectives, technical solutions and advantages of the present utility model more clear and understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0026] Example 1: As Figures 1 to 5 shown, a Joule furnace for treating radioactive waste liquid includes a furnace body. A furnace cavity 11 is provided inside the furnace body. A feed pipe 12 and an exhaust pipe 13 communicating with the furnace cavity 11 are connected to the top of the furnace body. A stirring device 2, a liquid level measuring device 3 and a temperature measuring device 4 are installed inside the furnace cavity 11, and a heating device is circumferentially arranged thereon. The bottom communicates with a discharge channel 14.

[0027] Radioactive waste liquid enters the furnace cavity 11 through the feed pipe 12. The heating device fully calcines the radioactive waste liquid to decompose, concentrate and evaporate it. Then, glass additives are added through the feed pipe 12 and melted and mixed together. After the processing is completed, it is discharged from the discharge channel 14. The gas generated during the calcination process is discharged through the exhaust pipe 13. The stirring device 2 is provided to make the radioactive waste liquid evenly heated and fully and evenly mixed with the glass liquid. The liquid level measuring device 3 can monitor the liquid level height in the furnace cavity 11 in real time, adjust the feeding amount according to the measurement result, so that the radioactive waste liquid in the furnace cavity 11 is in the designed working range. The temperature measuring device 4 can monitor the temperature in the furnace cavity 11 in real time, adjust the feeding amount in time according to the measurement result and control the switch of the heating device, so that the temperature of the radioactive waste liquid is in the designed working range. The combined use of the liquid level measuring device 3 and the temperature measuring device 4 improves the accuracy of judging the state of the radioactive waste liquid. It can not only judge the processing time of the radioactive waste liquid in the furnace, the interval time and the addition amount of adding radioactive waste liquid according to the measurement result, but also add glass additives according to the measurement result. Therefore, the Joule furnace designed in this embodiment integrates various detection devices and heating devices, and has the beneficial effects of being easy to judge the state of the radioactive waste liquid in the furnace, evenly heating the radioactive waste liquid, good heat preservation and heat insulation effect, being able to effectively isolate radioactivity, and being able to flexibly adjust the heating temperature and heating timing at different positions.

[0028] Embodiment 2: On the basis of Embodiment 1, the shell of the furnace body is preferably designed. As Figure 1 shown, the shell of the furnace body includes an outer shell 51 and a furnace lining fixed inside the outer shell 51. The furnace cavity 11 is opened in the furnace lining. The outer shell 51 is made of metal material. The furnace lining includes an outer layer furnace lining 52, a middle layer furnace lining 53 and an inner layer furnace lining 54. The outer layer furnace lining 52 is made of ceramic fiber board, the middle layer furnace lining 53 is made of clay insulation brick, and the inner layer furnace lining 54 is divided into an upper furnace lining 541 and a lower furnace lining 542. The demarcation line between the upper furnace lining 541 and the lower furnace lining 542 is the highest liquid level line in the furnace. The upper furnace lining 541 is made of zircon corundum, the lower furnace lining 542 is made of clay brick and chrome corundum, and the chrome corundum layer is located inside the clay brick layer. The multi-layer setting of the furnace lining can play an effective role in heat preservation and heat insulation. The outer layer furnace lining 52 made of fiber board has good heat preservation effect and is easy to install. The middle layer furnace lining 53 made of clay insulation brick can better insulate heat. The chrome corundum selected for the part of the inner layer furnace lining 54 in direct contact with the radioactive waste liquid has the functions of corrosion resistance and preventing radioactive substances from leaking. According to the highest liquid level line in the furnace, the inner layer furnace lining 54 is divided into an upper furnace lining 541 and a lower furnace lining 542. Since the lower furnace lining 542 needs to be in direct contact with the radioactive waste liquid, its temperature is higher and the corrosion is stronger. Therefore, the lower furnace lining 542 adopts a double-layer structure. The innermost layer is made of chrome corundum layer, which can effectively prevent radioactive substances from leaking. The clay brick layer outside the chrome corundum layer further improves the heat preservation effect and can also reduce the material cost.

[0029] Example 3: On the basis of the above embodiments, the stirring device 2 is preferably designed. As Figure 2 shown, the stirring device 2 includes a hose 21. The hose 21 is made of a rubber hose, and its lower part is connected to a spray pipe 22. The spray pipe 22 is made of a nickel-based material. The bottom of the spray pipe 22 is arranged obliquely and extends into the radioactive waste liquid. Compressed air is passed through the hose 21. By continuously injecting compressed air, bubbles are formed in the radioactive waste liquid to produce a stirring effect, so that the radioactive waste liquid and the glass melt are fully mixed. And the bottom of the spray pipe 22 is arranged obliquely, and the bubbling stirring effect is better.

[0030] The spray pipe 22 is fixed in an auxiliary support 6 on the top of the furnace body. The auxiliary support 6 includes a connecting pipe 61 vertically passing through the furnace top. The furnace top is fixed with an installation channel 62 extending vertically downward. The connecting pipe 61 passes through the installation channel 62 and is welded and fixed to it. The top of the connecting pipe 61 is welded and fixed to the lower flange of a flange plate 63. An insulating ceramic layer 8 is provided between the upper flange and the lower flange of the flange plate 63. The spray pipe 22 is fixed in the flange plate 63, passes through the upper flange and is welded and fixed to it without contacting the lower flange. The insulating ceramic layer 8 separates the energized spray pipe 22 from the furnace body to prevent its shell from being energized.

[0031] Example 3: On the basis of the above embodiments, the liquid level measuring device 3 is preferably designed. As Figure 3 shown, the liquid level measuring device 3 includes a hose 21. The hose 21 is made of a rubber hose, and its lower part is connected to a liquid level pipe 31. The lower part of the liquid level pipe 31 extends into the furnace cavity 11, and a pipe cover 32 is integrally connected to the bottom. The pipe cover 32 is made of a nickel-based material. The pipe cover 32 extends into the radioactive waste liquid. A constant gas is passed through the hose 21, and the top is connected to a pressure measuring device. The pressure measuring device can be a pressure gauge or a pressure meter. When the liquid level of the radioactive waste liquid changes, the pressure in the pipe cover 32 changes, and the data of the measuring instrument changes accordingly, so as to be converted into the change of the liquid level height of the radioactive waste liquid. The liquid level height of the radioactive waste liquid is judged by measuring the pressure change in the furnace cavity 11.

[0032] The liquid level pipe 31 is fixed in an auxiliary support 6 on the top of the furnace body. The auxiliary support 6 includes a connecting pipe 61 vertically passing through the furnace top. The furnace top is fixed with an installation channel 62 extending vertically downward. The connecting pipe 61 passes through the installation channel 62 and is welded and fixed to it. The top of the connecting pipe 61 is welded and fixed to the lower flange of a flange plate 63. An insulating ceramic layer 8 is provided between the upper flange and the lower flange of the flange plate 63. The liquid level pipe 31 is fixed in the flange plate 63, passes through the upper flange and is welded and fixed to it without contacting the lower flange. The insulating ceramic layer 8 separates the energized liquid level pipe 31 from the furnace body to prevent its shell from being energized.

[0033] Example 5: Based on Example 1, the temperature measurement device 4 is preferably designed. As Figure 4 shown, the temperature measurement device 4 includes a number of thermocouples 41 arranged at different heights. The thermocouples 41 are platinum-rhodium thermocouples 41. A protective tube 42 is sleeved outside the thermocouples 41. The protective tube 42 is made of a nickel-based material, and its bottom extends into the radioactive waste liquid. The temperature measurement part of the thermocouple 41 is located at the bottom of the protective tube 42, and its connecting wire extends upward along the inner wall of the protective tube 42 and is connected to a signal box 43 outside the protective tube 42. Since the thermocouples 41 are arranged at different heights, and the liquid level height of the radioactive waste liquid in the furnace cavity 11 will change, and the temperatures above and below the liquid level are different, the real-time temperature and liquid level of the solution in the furnace can be monitored through the temperature signals displayed by different thermocouples 41 corresponding to the signal box 43. Then, according to the measured temperature and liquid level and combined with the measurement results of the liquid level measurement device 3, the feeding is adjusted to make the materials in the Joule furnace always in the designed working range.

[0034] The protective tube 42 is fixed in an auxiliary support 6 at the top of the furnace body. The auxiliary support 6 includes a connecting pipe 61 vertically passing through the furnace top. There is a vertically downward extending installation channel 62 fixed to the furnace top. The connecting pipe 61 passes through the installation channel 62 and is welded and fixed to it. The top of the connecting pipe 61 is welded and fixed to the lower flange of a flange plate 63. An insulating ceramic layer 8 is provided between the upper flange and the lower flange of the flange plate 63. The protective tube 42 is fixed in the flange plate 63, passes through the upper flange and is welded and fixed to it without contacting the lower flange. The insulating ceramic layer 8 separates the energized protective tube 42 from the furnace body to prevent its shell from being energized. In addition, it should be noted that the feeding pipe 12, the stirring device 2, the liquid level measurement device 3, and the temperature measurement device 4 can all be fixedly connected to the furnace top through the same auxiliary support 6 to save material costs, or can be fixedly connected to the furnace top through different auxiliary supports 6 to reduce the processing difficulty, and can be designed according to actual needs.

[0035] Example 5: Based on Example 1, the heating device is preferably designed. As Figure 1 and Figure 5As shown in the figure, the heating device includes a number of electrode devices symmetrically arranged inside the furnace body. Each pair of electrode devices is arranged symmetrically about the central axis of the furnace body from left to right. Each electrode device includes an electrode head 71 partially extending into the furnace cavity 11, with a part of the electrode head 71 immersed in the radioactive waste liquid. One side of the electrode head 71 is fixedly connected to a horizontally arranged electrode shaft tube 72. The tail end of the electrode shaft tube 72 passes through the side wall of the furnace body and is connected to an electrode switch. The electrode shaft tubes 72 of each pair of electrode devices are respectively connected to positive and negative electrode pairs. There are 4 pairs of electrode devices, including a pair of main electrodes 73 below the lowest liquid level line, a pair of secondary electrodes 74 located below the main electrodes 73, a pair of freeze-thaw electrodes 75 at the bottom of the furnace cavity 11, and a pair of discharge electrodes 76 at the discharge port. By using the main electrodes 73 and the secondary electrodes 74 in combination, the heating temperature of the Joule furnace can be flexibly adjusted. When the temperature in the furnace is insufficient, the main electrodes 73 and the secondary electrodes 74 are turned on together for heating. When the temperature in the furnace is too high, the heating temperature can be reduced by turning off the secondary electrodes 74. In addition, the main electrodes 73 and the secondary electrodes 74 can be cross-connected to heat radioactive waste liquids at different liquid levels, and the heating area is more evenly arranged. The freeze-thaw electrodes 75 and the discharge electrodes 76 are respectively located at the bottom of the furnace cavity 11 and the discharge port. Therefore, the working state and the discharging state can be adjusted by turning on and off. When the radioactive waste liquid is being calcined, the freeze-thaw electrodes 75 and the discharge electrodes 76 are in the off state, and the radioactive waste liquid at this position cools and solidifies. When discharging is required, both are in the on state, and the radioactive waste liquid warms up and melts and is discharged from the discharge port. By using a variety of electrode pairs in combination, the heating timing and heating duration of radioactive waste liquids at different positions in the furnace cavity 11 are controlled, which is more conducive to fully calcining the radioactive waste liquid and controlling its discharging.

[0036] Furthermore, a cooling channel 77 through which a fluid medium can circulate is provided inside the electrode head 71 and the electrode shaft tube 72. The cooling channel 77 surrounds inside the electrode head 71 and the electrode shaft tube 72. Cold air or cooling water is passed through the cooling channel 77. An inlet flange 78 is fixed at its inlet, and the inlet flange 78 is connected to the pipeline of a cooling source. The outlet is connected to a silencer 79. The silencer 79 can reduce the sound when the gas flows, and has a noise reduction effect. The inlet flange of the silencer 79 and the silencer 79 are fixed on the outer wall of the furnace body. Through the cooling channel 77 surrounding inside the electrode head 71 and the electrode shaft tube 72, the cooling medium can evenly cool different positions of the electrode head 71 and the electrode shaft tube 72 through the cooling channel 77, preventing the heating temperature from being too high and exceeding the maximum limit that the components can withstand, resulting in component damage.

[0037] As Figure 5As shown, a thermocouple 41 is further provided inside the electrode shaft tube 72, and a protective tube 42 is sleeved outside the thermocouple 41. The electrode shaft tube 72 is sleeved circumferentially around the protective tube 42. The temperature measuring part of the thermocouple 41 is located inside the electrode head 71, and its connecting wire passes through the protective tube 42 and is connected to the thermocouple plug. The outer circumference of the protective tube 42 is a cooling channel 77. The setting of the thermocouple 41 can monitor the temperature of the electrode head 71 in real time, heat or cool in time by monitoring the temperature, and can also judge the state of the radioactive waste liquid at this place through the temperature.

[0038] Furthermore, an insulating ceramic layer 8 is provided circumferentially at the connection between the electrode shaft tube 72 and the outer shell 51 of the furnace body to prevent the outer shell 51 of the furnace body from being electrified, and the outer end is fixed on the side wall of the furnace body through the electrode support 70 to ensure the connection stability of the electrode device.

[0039] The above embodiments only express the specific implementation manners of the present application, and the description is relatively specific and detailed, but it should not be construed as a limitation to the protection scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the technical solution of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application.

Claims

1. A Joule furnace for treating radioactive liquid waste, characterized in that: The invention comprises a furnace body, wherein a furnace cavity (11) is arranged in the furnace body, a feed pipe (12) and an exhaust pipe (13) which are in communication with the furnace cavity (11) are connected to the top of the furnace body, a stirring device (2), a liquid level measuring device (3) and a temperature measuring device (4) are installed in the furnace cavity (11), a heating device is arranged in the circumference thereof, and the bottom is in communication with a discharge channel (14).

2. A Joule furnace for treating radioactive liquid waste according to claim 1, characterized in that: The shell of the furnace body comprises an outer shell (51) and a furnace lining fixed on the inner side of the outer shell (51), and the furnace cavity (11) is arranged in the furnace lining; the outer shell (51) is made of metal material, and the furnace lining comprises an outer furnace lining (52), a middle furnace lining (53) and an inner furnace lining (54), wherein the outer furnace lining (52) is made of ceramic fiber board, the middle furnace lining (53) is made of clay insulation brick, and the inner furnace lining (54) is divided into an upper furnace lining (541) and a lower furnace lining (542), and the boundary line between the upper furnace lining (541) and the lower furnace lining (542) is the highest liquid level line in the furnace, wherein the upper furnace lining (541) is made of zirconium corundum, and the lower furnace lining (542) is made of clay brick and chrome corundum, and the chrome corundum layer is located on the inner side of the clay brick layer.

3. A Joule furnace for treating radioactive liquid waste according to claim 1, characterized in that: The stirring device (2) comprises a hose (21) which is fixedly connected downwardly to a nozzle (22). The nozzle (22) extends from an auxiliary support (6) on the furnace top into the radioactive waste liquid, and its bottom is arranged obliquely. Compressed air flows through the hose (21).

4. A Joule furnace for treating radioactive liquid waste according to claim 1, characterized in that: The liquid level measuring device (3) comprises a hose (21), the hose (21) being fixedly connected downwardly to a liquid level pipe (31), the liquid level pipe (31) extending from an auxiliary support (6) on the furnace top into the radioactive waste liquid, the bottom of which is fixedly connected to a pipe cover (32), and the top of the hose (21) being connected to a pressure measuring device.

5. A Joule furnace for treating radioactive liquid waste according to claim 1, characterized in that: The temperature measuring device (4) comprises a plurality of thermocouples (41) arranged in a staggered manner. A protective tube (42) is provided on the outer cover of the thermocouple (41). The bottom of the protective tube (42) extends from an auxiliary support (6) on the furnace top into the radioactive waste liquid. The temperature measuring part of the thermocouple (41) is located at the bottom of the protective tube (42).

6. A Joule furnace for treating radioactive liquid waste according to any one of claims 3 to 5, characterized in that: The auxiliary support (6) comprises a connecting pipe (61) vertically passing through the furnace top downwards, the connecting pipe (61) is fixedly connected to the furnace top, a flange (63) for mounting various components is fixed on the top of the connecting pipe (61), and an insulating ceramic layer (8) is provided in the middle of the flange (63).

7. A Joule furnace for treating radioactive liquid waste according to claim 1, characterized in that: The heating device comprises a plurality of pairs of electrode devices symmetrically arranged in the furnace body, each electrode device comprises an electrode head (71) extending into the radioactive waste liquid, the other side of the electrode head (71) is fixedly connected to a horizontally arranged electrode shaft tube (72), the tail end of the electrode shaft tube (72) passes through the side wall of the furnace body and is connected to an electrode switch.

8. A Joule furnace for treating radioactive liquid waste according to claim 7, characterized in that: The electrode device is provided with four pairs, including a pair of main electrodes (73) below the lowest liquid level line, a pair of secondary electrodes (74) below the main electrodes (73), a pair of freeze-thaw electrodes (75) at the bottom of the furnace cavity (11), and a pair of discharge electrodes (76) located at the discharge port.

9. A Joule furnace for treating radioactive liquid waste according to claim 7, characterized in that: The electrode head (71) and the electrode shaft tube (72) are provided with a cooling loop (77) in which a fluid medium can circulate, and the outlet of the cooling loop (77) is connected to a muffler (79); a thermocouple (41) is also provided in the electrode shaft tube (72), and a protective tube (42) is provided on the outer casing of the thermocouple (41), and a temperature measuring part thereof is located in the electrode head (71).

10. A Joule furnace for treating radioactive liquid waste according to claim 7, characterized in that: An insulating ceramic layer (8) is provided circumferentially at the connection between the electrode shaft tube (72) and the outer shell (51) of the furnace body, and is fixed to the outer wall of the furnace body via an electrode support (70).

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