Plasma torch and plasma furnace for disposing radioactive waste

Abstract

The utility model provides a plasma torch and a plasma furnace for disposing radioactive wastes, and aims to solve the technical problem of radioactive leakage when a cathode is replaced midway. The plasma torch comprises an anode tube which is internally provided with an anode material, one end of the anode tube is a nozzle, the other end of the anode tube is a connecting part, and the connecting part is provided with a working gas channel; one end of the cathode rod is movably arranged in the connecting part, the cathode rod is made of a cathode material, and a gap exists between the end part of the cathode rod and the anode material; the driving end of the driving part is in power connection with the cathode rod, and the driving part is used for driving the cathode rod to move into the anode tube; the cathode of the plasma power supply is electrically connected with the cathode rod, and the anode is electrically connected with the anode material; and the output end of the working gas supply device is communicated with the working gas channel. According to the plasma torch, the cathode rod is made to move in the connecting part through the driving piece, the distance between the cathode rod and the anode material is reduced, and therefore radioactive leakage caused by cathode material replacement is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to radioactive waste disposal technical field, specifically related to a kind of plasma torch and plasma furnace of disposal radioactive waste. BACKGROUND

[0002] With the rapid development of nuclear power industry, the number of radioactive waste generated in the operation and decommissioning process of nuclear power plant increases year by year, and the demand for disposal also increases, so the development of related radioactive waste treatment technology becomes a top priority.

[0003] Compared with traditional treatment technology, plasma gasification melting glass solidification technology has the advantages of wide application range, fast reaction speed, small secondary pollution, small tail gas quantity and compact equipment, etc., which can realize the decomposition gasification combustion of radioactive waste, high temperature melting of inorganic waste and solidification process of radionuclide in a set of system, greatly reduce the volume of waste, and obtain stable final waste body.

[0004] The mainstream plasma disposal radioactive waste technology in the market at present is to use nitrogen (or air) as the plasma carrier, to generate high-temperature plasma jet after ionization, to pyrolyze and gasify and melt the radioactive waste, and finally to form glass solidification body, to solidify nuclides and harmful heavy metals in the glass body, to realize volume reduction and harmless treatment.

[0005] In this process, due to the high temperature and high enthalpy characteristics of plasma arc itself, part of harmful nuclides such as Cs-137 can easily volatilize into flue gas under high temperature conditions, in addition, the core component of plasma torch, cathode, has a short service life, and in the process of treating radioactive waste, there is a problem of needing to replace the cathode in the middle, which increases the risk of radioactive leakage. INVENTION CONTENTS

[0006] In view of the technical problem of radioactive leakage in the process of replacing the cathode in the middle when treating radioactive waste, the utility model provides a kind of plasma torch and plasma furnace of disposal radioactive waste, connecting part is arranged at the end of anode tube, and cathode rod is movably arranged in connecting part, then when the distance between the end of cathode rod and anode material increases, cathode rod is moved in connecting part by driving part, to reduce the distance between cathode rod and anode material, so as to avoid radioactive leakage caused by replacing cathode material.

[0007] The technical scheme of the utility model is:

[0008] A kind of plasma torch of disposal radioactive waste, comprising:

[0009] Anode tube, anode material is arranged in the inside of anode tube, one end of anode tube is jet, and the other end is connecting part, working gas passage is arranged on connecting part;

[0010] A cathode rod movably arranged in the connecting portion, the cathode rod being made of cathode material, and a gap being present between the end of the cathode rod and the anode material;

[0011] A driving member, a driving end of the driving member being in power connection with the cathode rod, and the driving member being used to drive the cathode rod to move into the anode tube;

[0012] A plasma power supply, a negative electrode of the plasma power supply being in electrical connection with the cathode rod, and an anode of the plasma power supply being in electrical connection with the anode material;

[0013] A working gas supply device, an output end of the working gas supply device being in communication with the working gas channel.

[0014] Optionally, the application further comprises:

[0015] A standby rod, the structure and material of the standby rod being the same as those of the cathode rod, and one end of the standby rod being connectable with one end of the cathode rod.

[0016] Optionally, one end of the cathode rod is provided with external threads, and the other end of the cathode rod is provided with a threaded hole, and the external threads of one end of the standby rod are matchable with the threaded hole of one end of the cathode rod.

[0017] Optionally, one end of the anode tube is provided with a cathode base, and the cathode rod and the working gas channel are arranged on the cathode base.

[0018] Optionally, the cathode base is further provided with a sealing assembly.

[0019] Optionally, the anode tube is internally provided with a metal tube for confining an electric arc at one end of a nozzle.

[0020] Optionally, the anode tube is internally provided with a liquid cooling channel.

[0021] A plasma furnace comprising a plasma torch for disposal of radioactive waste.

[0022] Optionally, a nozzle of the plasma torch is located in the plasma furnace, and a blast pipe is arranged between the plasma torch and the plasma furnace.

[0023] Optionally, the blast pipe is internally provided with a cyclone vane.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] The connecting portion is arranged at the end of the anode tube, the cathode rod is movably arranged in the connecting portion, and when the gap between the end of the cathode rod and the anode material is increased, the cathode rod is moved in the connecting portion by the driving member, so that the gap between the cathode rod and the anode material is reduced, thereby avoiding radioactive leakage caused by replacement of the cathode material.

[0026] The wall-attached air is formed by adding a wind pipe between the plasma torch and the plasma furnace and passing air flow in the wind pipe, and the wall-attached air is sprayed from around the spray port to wrap the plasma flame, so that the high-temperature flame and the volatile nuclide are prevented from contacting for a short time, thereby avoiding that part of harmful nuclides are volatilized into the flue gas. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 It is a structural schematic diagram of the plasma torch;

[0029] Figure 2 It is a structural schematic diagram of the plasma furnace;

[0030] Figure 3 It is a structural schematic diagram of the driving member;

[0031] Figure 4 It is a structural schematic diagram of the cathode base. DETAILED DESCRIPTION

[0032] In the following, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0033] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. For the purpose of simplifying the present application's disclosure, the components and settings of specific examples are described in the following. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to numbers and / or letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0034] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0035] Embodiment one:

[0036] Reference Figure 1The embodiment discloses a plasma torch for disposing radioactive waste, which comprises an anode tube 110, a cathode rod 120, a driving member 130, a plasma power supply 140 and a gas supply device 150. The anode tube 110 is internally provided with an anode material 160, and one end of the cathode rod 120 is connected to one end of the anode tube 110. The cathode rod 120 and the anode material 160 are electrically connected to the negative pole and the positive pole of the plasma power supply 140 respectively, so that an electric arc is generated in the anode tube 110. The electric arc in the anode tube 110 is blown out from a nozzle by the gas supply device 150. When the cathode rod 120 is ablated, the cathode rod 120 is driven to move into the anode tube 110 by the driving member 130.

[0037] Specifically, the anode tube 110 is in a tubular structure and penetrates through both ends, and the anode tube 110 is internally provided with a tubular anode material 160, which is generally a copper alloy. One end of the anode tube 110 is a nozzle, and the other end is a connecting portion, and the connecting portion is further provided with a working gas channel 172.

[0038] The cathode rod 120 is in a rod structure, and the cathode rod 120 is made of special materials, such as cerium-tungsten alloy, hafnium alloy, silver alloy and the like.

[0039] During installation, the interval between the one end of the cathode rod 120 arranged in the connecting portion and the end portion of the anode material 160 is 2-3 mm.

[0040] The driving end of the driving member 130 is in power connection with the cathode rod 120.

[0041] The output end of the gas supply device 150 is in communication with the working gas channel 172, and the working gas is generally inert gas or compressed air.

[0042] The working principle of the embodiment is that the connecting portion is arranged at the end portion of the anode tube 110, and the cathode rod 120 is movably arranged in the connecting portion. When the ablation phenomenon occurs at the end portion of the cathode rod 120, the interval between the end portion of the cathode rod 120 and the end portion of the anode material 160 is increased. The cathode rod 120 is driven to move in the connecting portion by the driving member 130, so that the interval between the end portion of the cathode rod 120 and the end portion of the anode material 160 is reduced. In this way, the normal work of the plasma torch 100 can be maintained, and radioactive leakage caused by replacement of the cathode material can be avoided.

[0043] Preferably, one end of the cathode rod 120 is provided with external threads, and the other end is provided with a threaded hole. The plasma torch 100 further comprises a plurality of spare cathode rods 120, which can be referred to as spare rods. When the cathode rod 120 installed in the connecting portion is severely ablated, i.e., is about to be ablated, the spare rod is connected with the cathode rod 120 through threaded matching, so as to lengthen the cathode rod 120, thereby greatly improving the service life of the cathode, achieving several times or even dozens of times, greatly improving the durability, and reducing the risk of radioactive leakage caused by replacement of the cathode in actual nuclear power engineering projects.

[0044] In one specific embodiment:

[0045] One end of the anode tube 110 is provided with a cathode base 170. The cathode base 170 is a hollow structure. The middle part of the base of the cathode is a connecting portion for insertion of the cathode rod 120. In addition, the cathode base 170 is further provided with a sealing assembly 180.

[0046] By providing the cathode base 170, the working gas channel 172 and the sealing assembly 180 can be conveniently installed. By providing the sealing assembly 180, the periphery of the cathode rod 120 can be tightly sealed, which not only effectively isolates the inside of the anode tube 110 from the outside connection, but also fixes the working position of the cathode rod 120 to ensure its normal work.

[0047] Preferably, the cathode base 170 is a hollow cylindrical structure, and a plurality of bolt holes 173 are arranged on the circumference of the cathode base 170. The sealing assembly 180 described above comprises a sealing ring 181 made of an insulating flexible material (such as boron nitride fiber reinforced composite material) and a bolt 182 for pressing the sealing ring 181. The bolt 182 is matched with the bolt hole 173 on the cathode base 170.

[0048] In addition, as shown in Figure 4 The inner side wall of the cathode base 170 is provided with an embedded groove 171, and the sealing ring 181 is located in the embedded groove 171. An arc-shaped pressing plate 183 is further arranged in the embedded groove 171, and the end of the bolt 182 is in contact with the pressing plate 183. When the cathode rod 120 is installed in the connecting portion, the pressing plate 183 is pressed by the bolt 182, and then the sealing ring 181 is pressed by the pressing plate 183, so as to realize the sealing of the periphery of the cathode rod 120. By providing the pressing plate 183, the purpose is to ensure that the pressure of the sealing ring 181 on the periphery of the cathode rod 120 is balanced.

[0049] In another specific embodiment:

[0050] The anode tube 110 is internally provided with a metal tube 111 for confining the arc on one side of the nozzle, and the metal tube 111 is made of copper. The anode tube 110 is internally provided with a liquid cooling channel 112, and the liquid cooling channel 112 covers the metal tube 111. By arranging the liquid cooling channel 112 and passing cooling liquid in the liquid cooling channel 112, the metal tube 111 can be cooled.

[0051] In the embodiment, copper is selected as the metal tube 111 for confining the arc, mainly because copper has good electrical conductivity, thermal conductivity and low cost.

[0052] In another specific embodiment,

[0053] Referring to Figure 3 The driving member 130 includes a servo motor 131 and a pair of driving wheels 132, wherein the output shaft of the servo motor 131 is in power connection with the two driving wheels 132, the two driving wheels 132 have a spacing therebetween, the axes of the two driving wheels 132 are parallel to each other, and the two driving wheels 132 rotate on the same plane. The two driving wheels 132 rotate at the same speed and in opposite directions under the driving of the servo motor 131.

[0054] Generally, two gears 133 with the same parameters and meshing with each other are installed on the output shaft of the servo motor 131, and the output shaft of the servo motor 131 is coaxially connected with one of the gears 133, and the two gears 133 achieve the requirement of the two driving wheels 132.

[0055] During installation, the two driving wheels 132 are respectively located on the two sides of the cathode rod 120 and generate clamping force on the cathode rod 120 from the two sides of the cathode rod 120, so that the cathode rod 120 can be directly driven to approach the anode material 160 under the driving action of the servo motor 131.

[0056] Embodiment two:

[0057] Referring to Figure 2 The embodiment discloses a plasma furnace, which comprises the plasma torch 100 for disposing radioactive waste described in embodiment one. Specifically, the plasma torch 100 is installed above the furnace body of the plasma furnace 200, and the furnace body is made of refractory material which is resistant to high temperature and corrosion to insulate the inside of the furnace body.

[0058] After the plasma torch 100 works normally, the high-temperature plasma flame output by the plasma torch 100 melts the radioactive waste in the furnace body at high temperature to form a molten pool, and the radioactive waste in the molten pool is melted by the high-temperature plasma flame to form a glass body.

[0059] In the melting process, part of the harmful nuclide (Cs-137, I-131, Sr-90, Co-60, etc.) is effectively solidified in the glass body, and through professional leaching test, it can be verified that the harmful nuclide will not cause radiation damage to the outside from the inside of the glass body.

[0060] In one of the specific embodiments:

[0061] The installation position between the plasma torch 100 and the furnace body is provided with an air pipe 210, the air pipe 210 is wrapped on the plasma torch 100, and the two ends of the air pipe 210 are located outside and inside the furnace body respectively, one end of the air pipe 210 is in communication with the output end of the fan.

[0062] By adding the air pipe 210 between the plasma torch 100 and the furnace body, and passing the airflow in the air pipe 210, the wall-attached wind is formed, the wall-attached wind is sprayed from around the nozzle, the plasma flame is wrapped, the high-temperature flame and the volatile nuclide are prevented from contacting for a short time, so that part of the harmful nuclide is prevented from volatilizing into the flue gas, and the safety is improved.

[0063] Preferably, the air pipe 210 is provided with a cyclone vane, the wall-attached wind is sprayed from around the nozzle after passing through the cyclone vane, a cyclone airflow is formed, the wall-attached wind cyclone structure makes the plasma torch 100 installed on the furnace body, and the refractory material is protected from being burned by the high-temperature plasma flame.

[0064] The above-mentioned embodiments only express the specific implementation of the present application, the description is more specific and detailed, but it cannot be understood as the limitation of the patent range of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which belong to the protection range of the present application.

Claims

1. A plasma torch for disposal of radioactive waste, characterized in that, The application relates to a plasma torch for treating radioactive waste. The plasma torch comprises: an anode tube, which is internally provided with anode material, one end of the anode tube being a nozzle and the other end being a connecting part, the connecting part being provided with a working gas channel; a cathode rod, one end of which is movably arranged in the connecting part, the cathode rod being made of cathode material, and a gap being formed between the end of the cathode rod and the anode material; a driving member, a driving end of which is in power connection with the cathode rod and used for driving the cathode rod to move into the anode tube; a plasma power supply, a negative electrode of which is in electric connection with the cathode rod and a positive electrode of which is in electric connection with the anode material; 2. The plasma torch for disposal of radioactive waste according to claim 1, characterized in that, a working gas supply device, an output end of which is in communication with the working gas channel. The application further comprises:

3. The plasma torch for disposal of radioactive waste according to claim 2, characterized in that, a standby rod, which is identical with the cathode rod in structure and material, one end of the standby rod being connectable with one end of the cathode rod.

4. The plasma torch for disposal of radioactive waste according to claim 1, wherein, One end of the cathode rod is provided with external threads, and the other end is provided with a threaded hole, the external threads of one end of the standby rod being matchable with the threaded hole of one end of the cathode rod.

5. The plasma torch for disposal of radioactive waste according to claim 4, characterized in that, One end of the anode tube is provided with a cathode base, and the cathode rod and the working gas channel are arranged on the cathode base.

6. The plasma torch for disposal of radioactive waste material of claim 1, wherein, The cathode base is further provided with a sealing assembly.

7. The plasma torch for disposal of radioactive waste according to claim 6, characterized in that, The anode tube is internally provided with a metal tube for confining an electric arc at one end of the nozzle. The anode tube is internally provided with a liquid cooling channel.

9. The plasma furnace of claim 8, wherein, 8. A plasma furnace comprising the plasma torch for treating radioactive waste according to any one of claims 1-7.

10. The plasma furnace of claim 9, wherein, The nozzle of the plasma torch is arranged in the plasma furnace, and a blast pipe is arranged between the plasma torch and the plasma furnace. The blast pipe is internally provided with a cyclone blade.

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