Novel plasma lead bismuth furnace for treating radioactive waste

Abstract

The invention belongs to the field of radioactive waste treatment, and particularly relates to a novel plasma lead bismuth furnace for treating radioactive waste. A feeding port and a plasma torch are arranged at the top of the plasma furnace, and the plasma torch is used for heating a backing material and a glass material; solid lead-bismuth particles are adopted as the base material, the base material, the frit and the formula material enter the plasma furnace body through the feeding port, a lead-bismuth solution layer, a glass solution layer and a cold cap layer are sequentially formed in the plasma furnace body from bottom to top, the lead-bismuth solution layer and the glass solution layer are in a liquid state, and the cold cap layer is in a solid state; a feeding pipe is arranged on the side face of the plasma furnace, and radioactive waste particles to be treated are added into the lead-bismuth solution layer through the feeding pipe. Reliability of the molten pool can be improved, and slag-bonding blockage of the molten pool can be prevented; the problems of heavy metal volatilization, nuclide migration and the like are effectively inhibited; and the high-end energy synthesis gas is further generated while volume reduction and harmlessness are realized.

Description

Technical Field

[0001] The invention belongs to the field of radioactive waste treatment, and in particular relates to a novel plasma lead-bismuth furnace for treating radioactive waste. Background Art

[0002] With the continuous development of nuclear power in my country, the total amount of radioactive waste generated by the operation and decommissioning of nuclear power plants in the future will continue to increase. The research and development of high-reduction and volume reduction treatment technologies for nuclear waste has become one of the main driving forces and challenges for nuclear safety.

[0003] Compared with traditional treatment technologies, plasma incineration volume reduction and solidification technology has the advantages of wide applicability, fast reaction speed, low secondary pollution, small exhaust volume and compact equipment. It can realize the decomposition, gasification and combustion of organic waste, high-temperature gasification and melting of inorganic waste and solidification of radioactive nuclides in one system, greatly reducing the volume of waste and obtaining a stable final waste body.

[0004] Plasma high-temperature gasification and melting technology can be applied to the treatment of nuclear power plants, nuclear facility operations and decommissioning waste. The engineering application of this technology will provide a new approach for the treatment and disposal of radioactive waste.

[0005] Currently, plasma technology is primarily used to treat low- to medium-level radioactive waste, such as plastics, rubber, cotton products, and paper products. These wastes are primarily organic. The main radionuclides in the waste include 137Cs, 90Sr, 60Co, Ru, 3H, U, and Pu, primarily at low levels.

[0006] However, there are still many problems in the process of treating radioactive waste using plasma high-temperature gasification and melting technology:

[0007] 1. Generally, the process involves first gasifying (or incinerating) the gasified bottom ash, then subjecting it to plasma melting to achieve vitrification. This furnace type and process are indeed quite effective in reducing the volume of radioactive waste. However, it should also be noted that gasification followed by melting results in a more complex process.

[0008] 2. During the plasma gasification stage, there are problems with coking and blockage during the organic matter reaction process, leading to furnace shutdown. At the same time, the gasification process is uneven, which easily leads to a high reduction rate of the bottom ash after the reaction (the national standard requires a reduction rate of 5%). In actual engineering operation, it is difficult to achieve this requirement, and a reduction rate of 10% or even more often occurs, which causes a large amount of residual carbon to enter the next melting stage. The residual carbon has a high melting point and is difficult to melt into a glassy body during the melting stage. This part of the problem directly affects the volume reduction rate. The residual carbon may even cause poor fluidity of the molten pool and even block the discharge port.

[0009] 3. During the plasma melting stage, there is a problem of slag blockage at the discharge port, resulting in poor discharge;

[0010] 4. During the plasma melting stage, there is a large temperature difference between the center and the wall of the molten pool used for glass solidification, resulting in uneven temperature.

[0011] 5. The formula added as a co-solvent into the furnace is uneven and the effect is not ideal;

[0012] 6. The problem that volatile heavy metals cannot effectively enter the vitreous body to achieve solidification;

[0013] 7. Radioactive nuclide migration issues, etc.

[0014] 8. The intermediate process is complicated, resulting in high energy consumption. Summary of the Invention

[0015] The purpose of the present invention is to provide a new plasma lead-bismuth furnace for treating radioactive waste, which can improve the reliability of the melt pool and prevent slagging and blockage of the melt pool; effectively suppress problems such as heavy metal volatilization and nuclide migration; and further generate high-end energy synthesis gas while reducing volume and making it harmless.

[0016] The technical solution for achieving the purpose of the present invention is as follows:

[0017] A novel plasma lead-bismuth furnace for treating radioactive waste comprises: a plasma furnace, a feed port, a plasma torch, a base material, a glass material, a formula material, and a feed pipe. The plasma furnace is provided with a feed port and a plasma torch at the top. The plasma torch can be moved downward from the top to the bottom under the action of an actuator to heat the base material and the glass material. The base material is solid lead-bismuth particles. The base material, the glass material, and the formula material respectively enter the plasma furnace body through the feed port. A lead-bismuth solution layer, a glass solution layer, and a cold cap layer are sequentially formed inside the plasma furnace body from bottom to top. The lead-bismuth solution layer and the glass solution layer are in liquid form, and the cold cap layer is in solid form. A feed pipe is provided on the side of the plasma furnace. The insertion top of the feed pipe is located below the boundary between the glass solution layer and the lead-bismuth solution layer. The radioactive waste particles to be treated are added to the lead-bismuth solution layer through the feed pipe.

[0018] Furthermore, the radioactive waste particles to be treated are transported at high speed by oxygen and directly added into the lead-bismuth solution layer through a feeding pipe.

[0019] Furthermore, a material distributor is provided in the plasma furnace, which is located below the feed port and can rotate along its center. Through the rotation of the material distributor, under the action of centrifugal force, the formula material falls evenly on the glass solution layer during the falling process, forming a cold cap layer.

[0020] Furthermore, the formula material adopts silicon calcium aluminum boron components.

[0021] Furthermore, the plasma furnace uses corrosion-resistant and oxidation-resistant refractory materials, and the refractory materials insulate the high-temperature liquid inside the plasma furnace body.

[0022] Furthermore, the feed pipe includes a right feed pipe and a left feed pipe, and the right feed pipe and the left feed pipe are arranged in a circumferential direction along a horizontal plane.

[0023] Furthermore, a smoke exhaust port is provided on the side of the plasma furnace, and the smoke exhaust port is located above the cold cap layer, and the synthesis gas is discharged from the smoke exhaust port.

[0024] Furthermore, a glass liquid overflow port is provided on the side of the plasma furnace for discharging the glass liquid that exceeds the glass liquid overflow port.

[0025] Furthermore, a drain port is provided on the side of the bottom of the plasma furnace for draining the liquid in the plasma furnace.

[0026] Furthermore, a bottom blowing pipe is provided at the bottom of the plasma furnace, and nitrogen or carbon dioxide is blown into the bottom blowing pipe to control the temperature in the plasma furnace.

[0027] The beneficial technical effects of the present invention are:

[0028] 1. The present invention provides a new plasma lead-bismuth furnace for treating radioactive waste, which adopts plasma technology to treat radioactive waste, directly combines gasification and melting into one process, and completes the gasification and melting process inside the lead-bismuth molten pool, turning the two-step process into a one-step process, greatly simplifying the intermediate links, improving environmental protection performance, and reducing energy consumption; it effectively overcomes the defects of the existing process such as gasification first and then melting, which makes the process more complicated and has many problems in the intermediate process.

[0029] 2. The present invention provides a new type of plasma lead-bismuth furnace for treating radioactive waste. After the radioactive waste is pretreated (crushed, transported, etc.), oxygen is added to the lead-bismuth solution layer. The high-speed oxygen jet blows to strengthen the internal process disturbance of the lead-bismuth solution layer, making the temperature field inside the entire lead-bismuth solution layer more uniform, eliminating the problem of low-temperature dead zone; the treated radioactive waste particles are completely immersed in the glass solution layer and the lead-bismuth solution layer, and the thermal decomposition and gasification of the organic solid phase particles are completed in the liquid; all gasification decomposition reactions are completed inside the lead-bismuth melt pool, effectively avoiding the problem of coking and blockage.

[0030] 3. The present invention provides a novel plasma lead-bismuth furnace for treating radioactive waste. This furnace uses an oxygen jet to add the radioactive waste particles to be treated into the lead-bismuth solution layer, effectively enhancing the pyrolysis and gasification reactions of the radioactive particles within the lead-bismuth solution layer, making the reaction more intense and the pyrolysis more thorough. This significantly supports improving the efficiency and yield of the entire process.

[0031] Ultra-high temperature rapid cracking of hydrocarbons: The temperature inside the glass solution layer and the lead-bismuth solution layer is as high as 1200-1400℃. After the organic matter comes into contact, especially in the immersed state, the organic matter molecules are rapidly cracked within tens of milliseconds to form carbon products. The carbon atoms dissolve into the iron liquid, and the hydrogen atoms combine into hydrogen molecules to escape from the molten bath.

[0032] Rapid reaction of dissolved carbon and oxygen: Oxygen is blown into the molten pool. In the dynamic equilibrium of the chemical reaction, a certain amount of oxygen atoms or oxygen ions are dissolved in the solution. The reaction rate of dissolved oxygen and carbon is 1-2 orders of magnitude faster than the reaction rate of solid carbon and oxygen in the air. CO gas is quickly generated and escapes from the melt. It mixes with hydrogen formed by the cracking of other organic matter to form synthesis gas.

[0033] The process does not produce complex organic matter or other intermediate products: Due to the ultra-high temperature of over 1400°C, organic matter is ultra-high-temperature cracked into monatomic inorganic substances or diatomic gas molecules. There are no complex organic matter or intermediate products, such as the more deadly intermediate product dioxin, and no organic matter such as tar. This greatly improves the environmental protection effect and reduces the pressure on the back-end flue gas system treatment.

[0034] High carbon conversion rate: There is almost no residual undecomposed organic matter, and the carbon atom conversion rate is as high as 98-99%. Almost all organic matter is converted into the simplest inorganic substances - dissolved carbon or carbon monoxide gas and hydrogen. This solves the problem of substandard reduction rate and residual carbon accumulation in traditional plasma gasification processes. The proportion of syngas in the gas discharged from the exhaust port exceeds 90%.

[0035] The lead-bismuth solution layer wraps the radioactive waste in the liquid, which has a good inhibitory effect on the migration of radioactive nuclides, such as 137Cs and 90Sr.

[0036] 4. The present invention provides a new type of plasma lead-bismuth furnace for treating radioactive waste. The synthesis gas (whose main components are CO+H2) cooled by the cold cap layer is discharged from the smoke outlet; the proportion of synthesis gas in the gas coming out of the smoke outlet accounts for more than 90%; while reducing the volume of radioactive waste and making it harmless, it also produces high-end energy - high-purity synthesis gas; the synthesis gas can be purified to produce hydrogen in the next step, or it can be fed into a gas turbine for power generation, or it can be used as a chemical raw material, which is a high-end output energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic structural diagram of a new plasma lead-bismuth furnace for treating radioactive waste provided by the present invention.

[0038] In the figure: 1. Feed inlet; 2. Plasma furnace; 3. Material distributor; 4. Smoke exhaust port; 5. Cold cap layer; 6. Glass solution layer; 7-1. Right feed pipe; 7-2. Left feed pipe; 8. Lead-bismuth solution layer; 9. Plasma torch; 10. Glass solution overflow port; 11. Emptying port; 12. Furnace bottom; 13. Bottom air blowing pipe; 14. Refractory material. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0040] like Figure 1 As shown, the present invention provides a new type of plasma lead-bismuth furnace for treating radioactive waste, comprising: a plasma furnace 2, a feed port 1, a plasma torch 9, a base material, a glass material, a formula material, and a feed pipe;

[0041] A feed port 1 is provided on the top of the plasma furnace 2. A plasma torch 9 is installed on the top of the plasma furnace 2. The plasma torch 9 can move downward from the top to the bottom under the action of the actuator to heat the base material and the glass material.

[0042] The base material is solid lead-bismuth particles, which enter the furnace bottom 12 of the plasma furnace 2 through the feed port 1. The base material is heated by the high-temperature plasma jet of the plasma torch 9 and melted into a lead-bismuth solution layer 8, forming a lead-bismuth molten pool;

[0043] The glass material enters the plasma furnace 2 through the feed port 1 and is heated by the high-temperature plasma jet of the plasma torch 9 and the lead-bismuth molten pool to form a glass solution layer 6;

[0044] The formulated material enters the plasma furnace 2 through the feed port 1 and forms a cold cap layer 5;

[0045] A lead-bismuth solution layer 8, a glass solution layer 6, and a cold cap layer 5 are sequentially formed inside the plasma furnace 2 from bottom to top. The lead-bismuth solution layer 8 and the glass solution layer 6 are in liquid form, and the cold cap layer 5 is in solid form.

[0046] A feed pipe is provided on the side of the plasma furnace 2 , and the insertion top of the feed pipe is located below the boundary between the glass solution layer 6 and the lead-bismuth solution layer 8 .

[0047] A smoke exhaust port 4 is provided on the side of the plasma furnace 2 and is located above the cold cap layer 5. Synthesis gas is discharged from the smoke exhaust port 4 and is used for subsequent synthesis gas reforming, carbon capture, and purification to form high-purity hydrogen.

[0048] A glass overflow port 10 is provided on the side of the plasma furnace 2. The glass overflow port 10 is generally sealed. When the glass solution level of the glass solution layer 6 exceeds the glass overflow port 10, the glass overflow port 10 can be opened to allow the glass solution to flow out from the glass overflow port 10. The provision of the glass overflow port 10 effectively solves the problem of easy clogging of the discharge port.

[0049] The side of the furnace bottom 12 of the plasma furnace 2 is provided with an emptying port 11 for emptying the liquid in the plasma furnace 2. After the plasma furnace 2 has been running for a required time, the liquid in the plasma furnace 2 needs to be emptied for use before the furnace is stopped.

[0050] After obvious stratification is formed inside the plasma furnace 2 , the glass solution is regularly discharged from the glass solution overflow port 10 ; and the lead-bismuth solution is regularly discharged from the drain port 11 .

[0051] The bottom 12 of the plasma furnace 2 is provided with a bottom blowing pipe 13, through which nitrogen or carbon dioxide is blown into the plasma furnace 2 to control the temperature, thereby reasonably controlling the internal liquid temperature of the lead-bismuth solution layer 8 and controlling the effect of the pyrolysis and gasification reaction.

[0052] In a preferred embodiment, the feed pipe includes a right feed pipe 7-1 and a left feed pipe 7-2, and the right feed pipe 7-1 and the left feed pipe 7-2 are arranged in a circumferential direction along a horizontal plane.

[0053] In a preferred embodiment, the radioactive waste particles to be treated are transported at high speed using oxygen and are directly added to the lead-bismuth solution layer 8 through a feed pipe.

[0054] In a preferred embodiment, a material distributor 3 is provided within the plasma furnace 2. This distributor 3 is located below the feed port 1 and is capable of rotating about its center. The rotation of the distributor 3, under the action of centrifugal force, causes the formulated material to fall evenly above the glass solution layer 6 during its fall, forming a cold cap layer 5. Due to the action of the distributor 3, the cold cap layer 5 is very uniform in height across the horizontal cross-section within the furnace, which promotes uniformity of the temperature and flow fields within the furnace.

[0055] In a preferred embodiment, the plasma furnace 2 uses a refractory material 14 to insulate the high-temperature liquid inside the plasma furnace 2. The refractory material 14 needs to be corrosion-resistant and oxidation-resistant, and corundum is usually selected.

[0056] Specifically, in a novel plasma lead-bismuth furnace for treating radioactive waste provided by the present invention, the formation process of the lead-bismuth solution layer 8, the glass solution layer 6, and the cold cap layer 5 is as follows:

[0057] First, a small amount of base material (solid lead-bismuth particles) is placed at the bottom 12 of the plasma furnace 2. The plasma torch, under the action of the actuator, moves downward from the top of the plasma furnace 2 until it is close to the surface of the placed base material. At this time, the plasma torch is started, and a high-temperature plasma jet (2000-3000°C) is formed at the torch nozzle to heat the base material. After a period of time, the base material is melted into a lead-bismuth solution layer 8, forming a lead-bismuth molten pool. A slight negative pressure is applied in the furnace.

[0058] Small amounts of glass frit are gradually added from the feed port 1. Under the dual action of the high-temperature jet of the plasma torch and the high-temperature lead-bismuth molten pool, which has already formed a lead-bismuth solution layer 8, a glass solution layer 6 is formed. Because the density of the lead-bismuth solution is much greater than that of the glass solution and its chemical properties are inactive, it hardly reacts with water and air, and there is no violent chemical reaction. Therefore, a clear stratification phenomenon is formed inside the furnace body.

[0059] After the glass solution layer 6 is formed, the formulated materials (basic components are mainly silicon, calcium, aluminum, boron, etc.) are gradually added from the feed port 1; the formulated materials are evenly dropped on the glass solution layer 6 through the material distributor 3 to form a cold cap layer 5;

[0060] From then on, the entire furnace body is arranged in layers from top to bottom: that is, from top to bottom, there is a cold cap layer 5 (400-600°C), a glass solution layer 6 (1200-1400°C) and a lead-bismuth solution layer 8 (1000-1200°C); among them, the cold cap layer 5 basically exists in solid form, floating above the glass solution layer 6, and the glass solution layer 6 and the lead-bismuth solution layer 8 are both liquid.

[0061] The radioactive waste particles to be treated (i.e., particles of the radioactive waste to be treated that meet the particle size requirements after pretreatment (crushing, transportation, etc.)) are transported using high-speed oxygen and directly added to the lead-bismuth solution layer 8 through a feed pipe. The radioactive waste particles are transported into the lead-bismuth solution layer 8 using oxygen, and the transport velocity is maintained at a high level (up to the speed of sound) to ensure that the oxygen transport jet can penetrate the furnace bottom 12. This high-speed oxygen jet enhances the internal flow disturbance of the lead-bismuth solution layer, making the temperature field within the entire lead-bismuth solution layer more uniform and eliminating the problem of low-temperature dead zones. This disturbance creates favorable mixing conditions for reaction kinetics, has a positive effect on momentum transfer, heat energy transfer, and mass transfer within the molten pool, and achieves a process intensification effect. It can enhance the pyrolysis and gasification reactions of the radioactive waste particles within the lead-bismuth solution layer, making the reactions more intense and the pyrolysis more thorough, thus significantly supporting the improvement of efficiency and yield of the entire process.

[0062] The radioactive waste particles to be treated, which are injected at high speed and carried by oxygen, are completely immersed in the glass solution layer 6 and the lead-bismuth solution layer 8, and undergo pyrolysis and gasification of the organic solid phase particles. The main advantages are:

[0063] 1) Ultra-high-temperature rapid cracking of hydrocarbons: The temperatures inside the glass solution layer 6 and the lead-bismuth solution layer 8 reach as high as 1000-1400°C. Upon contact with organic matter, especially when submerged, the organic molecules rapidly crack within tens of milliseconds, forming carbon products. The carbon atoms dissolve into the lead-bismuth solution, while the hydrogen atoms combine to form hydrogen molecules that escape from the molten pool.

[0064] 2) Rapid reaction of dissolved carbon and oxygen: Oxygen is blown into the molten pool. In the dynamic equilibrium of the chemical reaction, a certain amount of oxygen atoms or oxygen ions are dissolved in the solution. The reaction rate of dissolved oxygen and carbon is 1 to 2 orders of magnitude faster than the reaction rate of solid carbon and oxygen in the air. CO gas is quickly generated and escapes from the melt. It mixes with hydrogen formed by the cracking of other organic matter to form synthesis gas, i.e., CO + H2;

[0065] 3) No complex organic matter or other intermediate products are produced during the process: Due to the ultra-high temperature of over 1400°C, organic matter is ultra-high-temperature cracked into monatomic inorganic substances or diatomic gas molecules. There are no complex organic matter or intermediate products, such as the more deadly intermediate product dioxin, and no organic matter such as tar.

[0066] 4) High carbon conversion rate: There is almost no residual undecomposed organic matter, and the carbon atom conversion rate is as high as 98-99%. Almost all organic matter is converted into the simplest inorganic substances: dissolved carbon or carbon monoxide gas and hydrogen. This solves the problem of substandard reduction rate and residual carbon accumulation in traditional plasma gasification process.

[0067] 5) During the treatment of radioactive waste particles, the lead-bismuth solution layer plays multiple roles and functions: liquid catalyst, catalyst, dispersant, heat storage body, flow matrix, carbon solution, oxygen dissolver, carbon-oxygen rapid reaction carrier, heavy-density liquid sealing body package, etc.

[0068] The lead-bismuth solution layer 8 wraps the radioactive waste in the liquid, which has a good inhibitory effect on the migration of radioactive nuclides, such as 137Cs and 90Sr.

[0069] After the organic components in the radioactive waste are completely decomposed in the lead-bismuth solution layer 8, the heat generated is transferred upward to the glass solution layer 6. At the same time, the inorganic components (such as silicon and calcium) in the treated object are melted in the glass solution layer 6 to form a vitreous body. A small amount of metal components in the treated object settles to the bottom of the furnace. The main function of the glass solution layer 6 is to melt and vitrify the remaining inorganic components after the radioactive waste is decomposed in the lead-bismuth solution layer, forming a stable vitreous body. The vitreous body can form a stable structure, solidifying most of the volatile heavy metal mercury (Hg, Cd, Pb, As, etc.) and radioactive nuclides (Cs, Sr, etc.) inside the vitreous body, achieving the purpose of harmlessness.

[0070] The cold cap layer 5 is primarily composed of solid formulation particles (i.e., formulation material). The formulation material typically uses related components such as silicon, calcium, aluminum, and boron. For example, the main components of the formulation material are SiO2, Al2O3, Na2O, B2O3, and CaO. The cold cap layer 5 primarily acts as a solvent for the molten glass layer 6, lowering the melting point of the glass, improving its fluidity, and solidifying more harmful substances into the glass body. Simultaneously, the formulation material falls from the feed port 1 onto the surface of the glass body 6, covering it and forming the cold cap layer, which has a relatively low temperature (400-600°C). A large amount of volatile heavy metals (such as Hg, Cd, Pb, and As) evaporate upon encountering heat in the high-temperature regions of the glass body 6 and the lead-bismuth solution layer 8. During their ascent, the cold cap layer 5 absorbs heat and cools the gases to below their volatilization point, before re-entering the glass body 6. Consequently, more volatile heavy metals are solidified within the glass body in the glass body, reducing the proportion of volatile heavy metals entering the flue gas and improving the environmental performance of the furnace.

[0071] At the same time, the presence of the cold cap layer 5 plays a significant role in preventing nuclide volatilization. Research has shown that all physical and chemical reactions between radioactive waste and glass additives during the conversion to glass occur within this cold cap layer. The cold cap structure effectively inhibits nuclide volatilization, allowing more harmful components to solidify into the vitreous body, thereby improving the effectiveness of radioactive disposal. For example, studies have shown that without the cold cap structure, over 30% of the Tc-99 would be lost (entering the flue gas). This data fully demonstrates the important role of the cold cap structure in inhibiting nuclide volatilization. The same principle can be applied to other volatile nuclides.

[0072] The gas (whose main components are CO+H2) cooled by the cold cap layer 5 is discharged from the exhaust port 4. The proportion of syngas in the gas coming out of the exhaust port is more than 90%.

[0073] Conventional radioactive waste treatment furnaces have exhaust temperatures above 1000°C, and a large amount of volatile heavy metals and related nuclides are transferred into the flue gas. At the same time, the high-temperature flue gas also causes problems such as flue wear and burning, and the economic efficiency is relatively poor. The furnace type of the present invention adopts a cold cap layer structure, which reduces the flue gas temperature at the exhaust port 4 (400-600°C), reduces the difficulty of flue gas system treatment, avoids negative conditions such as burning caused by high-temperature flue gas, and inhibits nuclide migration. It also solidifies more volatile heavy metals inside the glass body, avoiding the problems caused by the high-temperature flue gas generated by the above-mentioned conventional furnace type.

[0074] Conventional radioactive waste treatment furnaces are usually located in a high-temperature zone exceeding 1000 degrees Celsius, with the flue gas temperature at the discharge port also exceeding 1000 degrees Celsius. While this ensures the decomposition of organic matter, a large amount of volatile heavy metals, such as mercury (Hg), cadmium (Cd), lead (Pb), and arsenic (As), enter the flue gas, increasing the pressure on the subsequent flue gas treatment system. The furnace of the present invention utilizes a layered temperature control arrangement comprising a lead-bismuth solution layer 8, a glass solution layer 6, and a cold cap layer 5. This allows the treated material to be decomposed in the high-temperature zone of the lead-bismuth solution layer, with the organic components forming vaporized gas (CO+H2) and inorganic slag entering the glass solution layer to form a vitreous body. Furthermore, even after volatile heavy metals or nuclides are volatilized by heat in the high-temperature zone of the solution layer, they are cooled by the cold cap layer to below their volatilization point during their ascent, allowing them to re-enter the solution layer. This reduces the proportion of volatile heavy metals entering the flue gas and improves the environmental performance of the furnace.

[0075] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Any content not described in detail in the present invention may be adapted from existing technologies.

Claims

1. A new type of plasma lead-bismuth furnace for treating radioactive waste, characterized in that: include: A plasma furnace (2), a feed port (1), a plasma torch (9), a base material, a glass material, a formula material, and a feed pipe; the plasma furnace (2) is provided with a feed port (1) and a plasma torch (9) at the top, and the plasma torch (9) can be moved downward from the top to the bottom under the action of an actuator to heat the base material and the glass material; the base material adopts solid lead-bismuth particles, the base material, the glass material, and the formula material respectively enter the plasma furnace (2) through the feed port (1), and a lead-bismuth solution layer (8), a glass solution layer (6), and a cold cap layer (5) are sequentially formed inside the plasma furnace (2) from bottom to top; the lead-bismuth solution layer (8) and the glass solution layer (6) are in liquid form, and the cold cap layer (5) is in solid form; a feed pipe is provided on the side of the plasma furnace (2), and the insertion top position of the feed pipe is lower than the boundary between the glass solution layer (6) and the lead-bismuth solution layer (8), and the radioactive waste particles to be treated are added into the lead-bismuth solution layer (8) through the feed pipe.

2. A new plasma lead-bismuth furnace for treating radioactive waste according to claim 1, characterized in that: The radioactive waste particles to be treated are transported at high speed by oxygen and directly added into the lead-bismuth solution layer (8) through a feeding pipe.

3. A new type of plasma lead-bismuth furnace for treating radioactive waste according to claim 1, characterized in that: A material distributor (3) is provided in the plasma furnace (2). The material distributor (3) is located below the feed port (1) and is capable of rotating along its center. Through the rotation of the material distributor (3), under the action of centrifugal force, the formulated material falls evenly on the glass solution layer (6) during the falling process, forming a cold cap layer (5).

4. A new type of plasma lead-bismuth furnace for treating radioactive waste according to claim 1, characterized in that: The formula material adopts silicon calcium aluminum boron components.

5. The novel plasma lead-bismuth furnace for treating radioactive waste according to claim 1, characterized in that: The plasma furnace (2) uses a corrosion-resistant and oxidation-resistant refractory material (14), and the refractory material (14) keeps the high-temperature liquid inside the furnace body of the plasma furnace (2) warm.

6. A new type of plasma lead-bismuth furnace for treating radioactive waste according to claim 1, characterized in that: The feed pipe comprises a right feed pipe (7-1) and a left feed pipe (7-2), and the right feed pipe (7-1) and the left feed pipe (7-2) are arranged in a circumferential direction along a horizontal plane.

7. The novel plasma lead-bismuth furnace for treating radioactive waste according to claim 1, characterized in that: A smoke exhaust port (4) is provided on the side of the plasma furnace (2), the smoke exhaust port (4) is located above the cold cap layer (5), and the synthesis gas is discharged from the smoke exhaust port (4).

8. The novel plasma lead-bismuth furnace for treating radioactive waste according to claim 1, characterized in that: A glass liquid overflow port (10) is provided on the side of the plasma furnace (2) for discharging the glass liquid that exceeds the glass liquid overflow port (10).

9. The novel plasma lead-bismuth furnace for treating radioactive waste according to claim 1, characterized in that: A drain port (11) is provided on the side of the furnace bottom (12) of the plasma furnace (2) for draining the liquid in the plasma furnace (2).

10. The novel plasma lead-bismuth furnace for treating radioactive waste according to claim 1, characterized in that: A bottom blowing pipe (13) is provided at the bottom (12) of the plasma furnace (2), and nitrogen or carbon dioxide is blown into the bottom blowing pipe (13) to control the temperature in the plasma furnace (2).

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