A nuclear waste treatment system and method

Abstract

The present application relates to the field of environmental protection, and provide a kind of nuclear waste disposal system and processing method, nuclear waste disposal system includes waste resin temporary storage device, evaporated residual liquid temporary storage device, drying device, cooling equipment and waste gas waste liquid treatment equipment, the feed inlet of drying device is connected with the discharge port of waste resin temporary storage device and evaporated residual liquid temporary storage device respectively, for respectively drying treatment of waste resin and evaporated residual liquid, cooling equipment is communicated with the exhaust port of drying device, to carry out condensation treatment to high-temperature water vapor discharged from the exhaust port of drying device;Waste gas waste liquid treatment equipment is communicated with the cooling equipment, for treating waste gas and waste liquid generated after condensation of cooling equipment;The two independent processing systems of waste resin and evaporated residual liquid are integrated together in the present application, which can effectively reduce the number of subsequent auxiliary equipment of nuclear waste disposal system, and correspondingly reduce equipment cost and maintenance workload.

Description

A nuclear power waste treatment system and method Technical Field

[0001] This invention relates to the field of environmental protection technology, and more specifically, to a nuclear power waste treatment system and method. Background Technology

[0002] Nuclear power plants generate waste such as waste resin and residual liquid during operation. Since these two types of waste are radioactive, they must be rendered harmless.

[0003] Currently, due to the differences in physical form and composition of the two types of waste, different treatment systems are used to process them separately. However, considering the two treatment systems and their respective process routes, both systems use cooling equipment to treat the generated water vapor and waste gas and waste liquid treatment equipment to treat the generated waste gas and waste liquid. This results in resource waste due to the presence of the same treatment equipment in both systems, which in turn increases equipment costs and maintenance workload. Summary of the Invention

[0004] The problem addressed by this invention is how to effectively reduce the number of devices in the processing systems that handle the two types of waste generated by nuclear power, thereby reducing equipment costs and maintenance workload.

[0005] To address the aforementioned problems, this invention provides a nuclear power waste treatment system, comprising a waste resin temporary storage device, a residual vapor storage device, a drying device, a cooling device, and a waste gas and waste liquid treatment device. The inlet of the drying device is connected to the outlets of the waste resin temporary storage device and the residual vapor storage device, respectively, for drying the waste resin and residual vapor. The cooling device is connected to the exhaust port of the drying device to condense the high-temperature water vapor discharged from the exhaust port of the drying device. The waste gas and waste liquid treatment device is connected to the cooling device to treat the waste gas and waste liquid generated after condensation by the cooling device.

[0006] Optionally, the drying device includes a container, a heating structure, a driving component, and a stirring component. The heating structure is disposed on the side of the container. The driving component is connected to one end of the stirring component and is used to drive the stirring component to rotate. The stirring component is at least partially disposed inside the container and is used to tumble and rotate the waste material inside the container.

[0007] Optionally, the nuclear waste treatment system further includes a lifting device. The container includes a waste bin and a cover. The cover and the waste bin are arranged along the central axis of the container. The cover is a hollow cylindrical structure with an open bottom. The lifting device is connected to the waste bin and is used to drive the waste bin to rise and seal with the bottom opening of the cylindrical structure to form a stirring chamber. The stirring assembly passes through the cover and is located in the stirring chamber. The cover is provided with the inlet and the exhaust port.

[0008] Optionally, the drying device further includes a lifting assembly and a lifting frame. The driving assembly is disposed on the lifting frame. The end of the stirring assembly away from the driving assembly passes through the lifting frame and the barrel cover. The lifting assembly is disposed on the side wall of the barrel cover. The lifting end of the lifting assembly is connected to the lifting frame and is used to drive the lifting frame to drive the stirring assembly into or out of the waste barrel through the driving assembly.

[0009] Optionally, the lifting device includes a lifting assembly and a base, the lifting assembly being connected to the base, and the waste bin being disposed on the base; the heating structure includes a first heating element, the first heating element being disposed on the base.

[0010] Optionally, the container further includes a positioning door, which includes two arc-shaped plates for surrounding the waste bin to position it; the heating structure further includes a second heating element disposed on the arc-shaped plates.

[0011] Optionally, the drive assembly includes a first drive device and a second drive device, and the stirring assembly includes a first rotating shaft, a second rotating shaft, a commutator assembly, and a stirrer. The first drive device is driven connected to one end of the first rotating shaft, and the end of the first rotating shaft away from the first drive device is connected to the housing of the commutator assembly. The second rotating shaft is embedded in the first rotating shaft, and the second drive device is driven connected to one end of the second rotating shaft. The end of the second rotating shaft away from the second drive device is connected to the input gear of the commutator assembly, and the output gear of the commutator assembly is connected to the stirrer.

[0012] Optionally, the driving assembly includes a third driving device, and the stirring assembly includes a ribbon stirring shaft. The third driving device is drivenly connected to the ribbon stirring shaft to drive the ribbon stirring shaft to rotate.

[0013] Compared with the prior art, the present invention connects the inlet of the drying device to the outlets of the waste resin storage device and the residual evaporation liquid storage device, respectively. This allows waste resin discharged from the outlet of the waste resin storage device or residual evaporation liquid discharged from the outlet of the residual evaporation liquid storage device to enter the drying device through the inlet. Thus, the drying device can separately dry the waste resin from the waste resin storage device and the residual evaporation liquid from the residual evaporation liquid storage device. During the drying process, high-temperature water vapor is generated inside the drying device. This high-temperature water vapor is connected to the exhaust port of the drying device through a cooling device, allowing it to exit from the exhaust port and be transported via pipeline to the cooling device. The high-temperature water vapor is condensed by a low-temperature medium, such as cold water, generated by the cooling device, producing waste gas and waste liquid. These waste gas and waste liquid treatment devices are connected to the cooling device, thereby... This invention addresses the issue of waste gas and waste liquid generated after condensation from cooling equipment being treated separately using a waste gas and waste liquid treatment device. In contrast to existing technologies that require two independent treatment systems for two types of waste generated during nuclear power plant operation, such as waste resin and vapor residue, leading to increased equipment costs and maintenance workload due to the shared equipment in the treatment process, this invention integrates a single drying device within a nuclear power waste treatment system to dry both waste resin and vapor residue. A cooling device then condenses the high-temperature steam generated during drying to produce waste gas and waste liquid. Finally, the waste gas and waste liquid are treated using the waste gas and waste liquid treatment device. In other words, by integrating two separate treatment systems for waste resin and vapor residue, the number of subsequent auxiliary equipment in the nuclear power waste treatment system can be effectively reduced, thereby lowering equipment costs and maintenance workload.

[0014] Secondly, the present invention also provides a method for treating nuclear power waste, based on the nuclear power waste treatment system described above, comprising the following steps:

[0015] The waste resin in the waste resin temporary storage device or the residual liquid in the residual liquid storage device are respectively transported to the drying device.

[0016] The drying device is controlled to perform corresponding drying operations on the waste resin or the residual liquid inside it. The high-temperature water vapor generated during the drying operation is discharged from the exhaust port of the drying device and transported to the cooling equipment.

[0017] The cooling equipment is turned on to generate a low-temperature medium to condense the high-temperature water vapor, and to generate waste gas and waste liquid.

[0018] The waste gas and waste liquid treatment equipment treats the waste gas and waste liquid respectively.

[0019] Since the nuclear waste treatment method is based on the nuclear waste treatment system described above, it has at least all the technical effects of the nuclear waste treatment system, which will not be elaborated further here.

[0020] Optionally, controlling the drying device to perform corresponding drying operations on the waste resin or the residual liquid inside it includes:

[0021] When the waste material entering the container of the drying device is the waste resin: the container is evacuated; the stirring component of the drying device descends and penetrates into the waste bin of the container, and the waste resin in the waste bin is stirred in a heated environment;

[0022] When the waste material entering the container of the drying device is the residual liquid from evaporation: the container is evacuated; the stirring component of the drying device is lifted and detached from the waste container, and the residual liquid from evaporation in the waste container is heated. Attached Figure Description

[0023] Figure 1 is a schematic block diagram of the nuclear waste treatment system in an embodiment of the present invention;

[0024] Figure 2 is a connection structure diagram of the nuclear waste treatment system in an embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of one of the structures of the drying device in the embodiment of the invention;

[0026] Figure 4 is a second schematic diagram of the drying device in the embodiment of the invention;

[0027] Figure 5 is a third schematic diagram of the drying device in the embodiment of the invention;

[0028] Figure 6 is a schematic diagram of the structure of the driving component and the stirring component in the embodiment of the invention;

[0029] Figure 7 is a partial structural schematic diagram of the drying device in an embodiment of the invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1-Waste resin temporary storage device; 2-Residual liquid temporary storage device; 3-Drying device; 31-Container; 311-Waste bin; 312-Bin cover; 3121-Inlet; 3122-Exhaust port; 3123-Cleaning water inlet; 313-Positioning door; 32-Drive assembly; 321-First drive device; 322-Second drive device; 33-Agitator assembly; 331-First rotating shaft; 332-Second rotating shaft; 333-Commutator assembly; 334-Agitator; 34-Pressure detection device; 35-Liquid level detection device; 36-Lifting assembly; 37-Lifting frame; 38-Sealing structure; 4-Cooling equipment; 5-Waste gas and waste liquid treatment equipment; 51-Waste gas treatment device; 52-Waste liquid treatment device; 6-Combustible gas detection device; 7-Flame retardant device; 8-Base. Detailed Implementation

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] It should be noted that in the XZ coordinate system provided herein, the positive X-axis represents the right, the negative X-axis represents the left, the positive Z-axis represents the top, and the negative Z-axis represents the bottom. Furthermore, it should be understood that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] In the description of this specification, references to terms such as "embodiment," "one embodiment," and "one implementation" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or implementation is included in at least one embodiment or illustrative implementation of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or implementations.

[0036] To address the aforementioned technical problems, and in conjunction with Figures 1 and 2, this embodiment of the invention provides a nuclear power waste treatment system, comprising a waste resin temporary storage device 1, a residual liquid storage device 2, a drying device 3, a cooling device 4, and a waste gas and waste liquid treatment device 5. The inlet 3121 of the drying device 3 is connected to the outlets of the waste resin temporary storage device 1 and the residual liquid storage device 2, respectively, for drying the waste resin and residual liquid. The cooling device 4 is connected to the exhaust port 3122 of the drying device 3 to condense the high-temperature water vapor discharged from the exhaust port 3122 of the drying device 3. The waste gas and waste liquid treatment device 5 is connected to the cooling device 4 to treat the waste gas and waste liquid generated after condensation by the cooling device 4.

[0037] It should be noted that nuclear power plants typically generate two types of waste during normal operation: waste resin and residual distillate. Waste resin enters and is temporarily stored in waste resin storage device 1 through its inlet, while residual distillate enters and is temporarily stored in residual distillate storage device 2 through its inlet. The outlet of waste resin storage device 1 is connected to the inlet 3121 of drying device 3 via a water pump. This allows the water pump to extract waste resin from waste resin storage device 1 and transport it to drying device 3. Similarly, the outlet of residual distillate storage device 2 is connected to the inlet 3121 of drying device 3 via another water pump. This allows the water pump to extract residual distillate from residual distillate storage device 2 and transport it to drying device 3. The drying device 3 is used to dry the waste resin and residual liquid entering it, producing solid residue and high-temperature water vapor. The high-temperature water vapor is discharged from the exhaust port 3122 of the drying device 3 and transported along the pipeline to the cooling device 4, while the solid residue can be removed from the drying device 3. The cooling device 4 generates a low-temperature medium, such as circulating chilled water, to cool the high-temperature water vapor and produce waste gas and waste liquid.

[0038] The waste gas and waste liquid treatment equipment 5 includes a waste gas treatment device 51 and a waste liquid treatment device 52. The waste gas and waste liquid formed after condensation by the cooling equipment 4 enter the waste gas treatment device 51 and the waste liquid treatment device 52 through pipelines, respectively, so that the waste gas and waste liquid are treated by the waste gas treatment device 51 and the waste liquid treatment device 52 respectively. Among them, the waste gas treatment device 51 can adopt a mature nuclear power plant waste gas treatment system to treat the reflective waste gas after condensation by the cooling equipment 4, so that its radioactivity level is lower than the allowable value for environmental emissions, and then it is discharged into the environment. For example, low radioactivity aerobic waste gas treatment process, pressurized storage process, hydrogen-oxygen composite volume reduction process, etc., will not be described in detail here. Waste liquid treatment device 52 can adopt a mature nuclear power plant waste liquid treatment system to treat the radioactive waste liquid generated after condensation of cooling equipment 4, so that its radioactivity level is lower than the environmental emission allowable value, and then it is used as a makeup liquid for recycling or discharged into the environment. It usually involves a combination of five process units: storage, filtration, chemical precipitation, ion exchange, and evaporation. For example, storage refers to the storage treatment of waste liquid containing radionuclides with short half-lives; filtration refers to the filtration treatment of waste liquid to remove suspended solids and impurities; chemical precipitation refers to the addition of chemical flocculants or carriers to wastewater, which will generate a large amount of coagulated precipitates, and the radionuclides will be concentrated in the precipitates; evaporation is suitable for treating wastewater with high salt content, complex chemical composition, and high radioactivity level. After evaporation, most of the radionuclides remain in the concentrate, which is then solidified; ion exchange refers to the process in which the radioactive ions in the water are transferred to the ion exchange resin through the mutual exchange of ions between the two when the resin comes into contact with the radioactive waste liquid, thereby purifying the waste liquid.

[0039] In this embodiment, the inlet 3121 of the drying device 3 is connected to the outlets of the waste resin storage device 1 and the residual evaporation liquid storage device 2, respectively. This allows waste resin discharged from the outlet of the waste resin storage device 1 or residual evaporation liquid discharged from the outlet of the residual evaporation liquid storage device 2 to enter the drying device 3 through the inlet 3121. Thus, the drying device 3 can perform drying operations on the waste resin provided by the waste resin storage device 1 and the residual evaporation liquid provided by the residual evaporation liquid storage device 2, respectively. During the drying process, high-temperature water vapor is generated inside the drying device 3. This high-temperature water vapor is connected to the exhaust port 3122 of the drying device 3 via the cooling device 4. The high-temperature water vapor is discharged from the exhaust port 3122 of the drying device 3 and transported through pipelines to the cooling device 4. The high-temperature water vapor is condensed by a low-temperature circulating medium, such as cold water, generated by the cooling device 4, producing waste gas and waste liquid. These are then processed by the waste gas and waste liquid treatment device 5. The cooling device 4 is connected, so that the waste gas and waste liquid generated after condensation by the cooling device 4 can be treated separately by the waste gas and waste liquid treatment device 5. Compared with the existing technology, which requires two independent treatment systems to treat two types of waste generated during the operation of nuclear power plants, such as waste resin and vapor residue, and which increases equipment cost and maintenance workload due to the similarity of some equipment in the treatment process, the present invention only needs to use the drying device 3 in a nuclear power waste treatment system to dry the waste resin and vapor residue separately. Then, the high-temperature water vapor generated during the drying process can be condensed by the cooling device 4 to generate waste gas and waste liquid. Finally, the waste gas and waste liquid are treated by the waste gas and waste liquid treatment device 5. In other words, by integrating the two independent treatment systems for waste resin and vapor residue into one, the number of subsequent auxiliary equipment in the nuclear power waste treatment system can be effectively reduced, thereby reducing equipment cost and maintenance workload.

[0040] In this embodiment, the nuclear waste treatment system also includes a combustible gas detection device 6 and a flame retardant device 7. The combustible gas detection device 6 is installed on the pipeline between the exhaust port 3122 of the drying device 3 and the cooling device 4. The flame retardant device 7 is connected to the combustible gas detection device 6 and the drying device 3 respectively.

[0041] It should be noted that, under normal circumstances, the high-temperature steam generated by the drying device 3 during the drying process of waste resin and residual liquid will contain a certain amount of flammable gas. If the flammable gas is not dealt with in time, it may pose a risk of combustion and explosion to the drying device 3 and subsequent processing equipment. Therefore, a flammable gas detection device 6 is installed on the pipeline between the exhaust port 3122 of the drying device 3 and the cooling device 4, so that the content of flammable gas in the high-temperature steam can be detected in real time by the flammable gas detection device 6. The flame retardant device 7 is connected to the flammable gas detection device 6, so that the flame retardant device 7 can be turned on or off according to the content detection value of the flammable gas detection device 6. The flame retardant device 7 is connected to the drying device 3. If the content detection value of flammable gas exceeds the set value, the flame retardant device 7 is activated. At this time, the flame retardant device 7 fills the container 31 of the drying device 3 with inert gas, thereby avoiding the risk of combustion and explosion.

[0042] The combustible gas detection device 6 includes multiple combustible gas detection sensors. The specific detection type of the sensors is determined according to the type of combustible gas, and is not specifically limited here. The flame retardant device 7 includes at least one carbon dioxide storage tank and an electric valve. The electric valve is installed on the connecting pipeline between the carbon dioxide storage tank and the drying device. The electric valve is signal-connected to the combustible gas detection device 6. When the content detected by the combustible gas detection device 6 exceeds a set value, the electric valve opens, allowing inert gas, such as carbon dioxide, to flow out of the carbon dioxide storage tank and enter the drying device 3 through the pipeline, thereby reducing the combustible gas content and avoiding the risk of combustion and explosion.

[0043] In one embodiment of the present invention, as shown in Figures 3 to 5, the drying device 3 includes a container 31, a heating structure, a driving component 32, and a stirring component 33. The heating structure is disposed on the side of the container 31. The driving component 32 is connected to one end of the stirring component 33 and is used to drive the stirring component 33 to rotate. The stirring component 33 is at least partially disposed inside the container 31 and is used to tumble and rotate the waste material inside the container 31.

[0044] It should be noted that by installing corresponding heating structures on the sides of the container 31, such as the circumferential sidewalls and bottom walls, the temperature inside the container 31 can be increased to heat and dry the waste materials, such as waste resin or residual liquid, forming solid residues and releasing high-temperature steam. Since at least a portion of the stirring assembly 33 is disposed inside the container 31, and the drive assembly 32 is connected to one end of the stirring assembly 33, the drive assembly 32 provides rotational driving force to the stirring assembly 33 when it is operating. This drives the stirring assembly 33 to tumble and rotate the waste materials inside the container 31, ensuring uniform heating and drying of the waste materials. This avoids partial agglomeration caused by uneven heating, effectively improving the drying efficiency and effect of the waste materials inside the container 31.

[0045] In one embodiment of the present invention, as shown in Figures 3 to 5, the nuclear waste treatment system further includes a lifting device. The container 31 includes a waste bin 311 and a cover 312. The cover 312 and the waste bin 311 are arranged along the central axis of the container 31. The cover 312 is a hollow cylindrical structure with an open bottom. The lifting device is connected to the waste bin 311 and is used to drive the waste bin 311 to rise and seal with the bottom opening of the cylindrical structure to form a stirring chamber. The stirring assembly 33 passes through the cover 312 and is located in the stirring chamber. The cover 312 is provided with the inlet 3121 and the exhaust port 3122.

[0046] It should be noted that the central axis of container 31 is parallel to the Z-axis in the coordinate system. The barrel cover 312 and the waste bin 311 are arranged along the central axis of container 31, meaning that the barrel cover 312 is positioned directly above the waste bin 311. The bottom of the barrel cover 312 is open, and the top of the waste bin 311 is open. The lifting device is connected to the waste bin 311, which can drive the waste bin 311 to rise or fall. When drying is required, the lifting device drives the waste bin 311 to rise and seal with the bottom of the barrel cover 312. The barrel cover 312 acts as a sealing cover for the waste bin 311, forming a stirring chamber with the inside of the waste bin 311. When it is necessary to stir the waste, such as waste resin, inside the waste bin 311, the drive assembly 32 drives the stirring assembly 33 to rotate, so that the waste inside the waste bin 311 in the stirring chamber is flipped and rotated for stirring. After the drying process is completed, the lifting device drives the waste bin 311 to descend away from the bin cover 312, making it easier to remove the waste bin 311 containing solid residue and then seal it. The heating structure can be installed on the side of the waste bin 311.

[0047] The barrel cover 312 is provided with an inlet 3121 and an exhaust port 3122. The waste resin temporary storage device 1 and the residual liquid storage device 2 are respectively connected to the inlet 3121 through pipelines, so that the waste resin or residual liquid enters the waste barrel 311 from the inlet 3121. The high-temperature water vapor generated by the waste in the waste barrel 311 during the heating and drying process will be discharged from the exhaust port 3122. The inlet 3121 and exhaust port 3122 on the barrel cover 312, compared with the inlet 3121 and exhaust port 3122 on the waste barrel 311, can prevent the waste in the waste barrel 311 from flowing out from the inlet 3121 or exhaust port 3122 during the stirring process.

[0048] In one embodiment of the present invention, as shown in Figures 3 to 5, the drying device 3 further includes a lifting assembly 36 and a lifting frame 37. The driving assembly 32 is disposed on the lifting frame 37. The end of the stirring assembly 33 away from the driving assembly 32 passes through the lifting frame 37 and the barrel cover 312. The lifting assembly 36 is disposed on the side wall of the barrel cover 312. The lifting end of the lifting assembly 36 is connected to the lifting frame 37 and is used to drive the lifting frame 37 to drive the stirring assembly 33 to enter or leave the waste barrel 311 through the driving assembly 32.

[0049] It should be noted that the lifting frame 37 is used to install the drive assembly 32. Therefore, the drive assembly 32 is mounted on the lifting frame 37 via its fixed end, such as the outer shell structure. In this case, the lifting frame 37 provides a mounting base for the drive assembly 32. The drive end, such as the rotating end, of the drive assembly 32 is connected to one end, such as the top end, of the stirring assembly 33. The end of the stirring assembly 33 furthest from the drive assembly 32, such as the bottom end, passes through the lifting frame 37 and the barrel cover 312. The lifting assembly 36 can be a lifting hydraulic cylinder. The fixed end, such as the outer shell, of the lifting hydraulic cylinder is located on the circumferential side wall of the barrel cover 312. The lifting end, such as the end of the hydraulic push rod, of the lifting hydraulic cylinder is connected to the lifting frame 37, thereby enabling the lifting frame 37 to be driven in different scenarios to move the stirring assembly 33 deeper into or out of the waste barrel 311. The number of lifting components 36 can be at least one set. When there are multiple lifting components 36, the multiple lifting components 36 are distributed at intervals on the circumferential side wall of the barrel cover. As long as the number and arrangement of the lifting components 36 can meet the requirement of driving the lifting frame 37 to drive the driving component 32 and the stirring component 33 to lift, they are all applicable to this technical solution, and will not be elaborated here.

[0050] When the waste material in the waste bin 311 is waste resin, the lifting device drives the waste bin 311 to rise and seal it with the bin cover 312. Then the lifting component 36 works, driving the lifting frame 37 to lower the driving component 32 and the stirring component 33, so that the lower end of the stirring component 33 is inside the waste bin 311. Then the driving component 32 works to drive the stirring component 33 to rotate, and then waste resin is added into the stirring chamber through the feed port. The stirring component 33 stirs the waste resin in the waste bin 311 in a heated environment to achieve rapid drying of the waste resin.

[0051] When the waste in the waste bin 311 is residual liquid from steaming, the lifting device drives the waste bin 311 to rise and seal it with the bin cover 312. The lifting component 36 works, driving the lifting frame 37 to lift the drive component 32 and the stirring component 33, so that the lower end of the stirring component 33 is disengaged from the waste bin 311. At the same time, the drive component 32 and the stirring component 33 stop working. Then, residual liquid from steaming is added into the stirring chamber through the feed inlet to dry the residual liquid from steaming in the waste bin 311 under heating environment, so as to achieve rapid drying of the residual liquid from steaming.

[0052] Throughout the mixing operation, the position of the cover 312 remains fixed. Before the mixing operation, the waste bucket 311 rises and seals with the cover 312. After the mixing operation is completed, the waste bucket 311 descends to move away from the cover 312.

[0053] In one embodiment of the present invention, as shown in FIG4, the nuclear waste treatment system further includes a vacuuming device (not shown in the figure) and a pressure detection device 34. The vacuuming device is connected to the shroud 312 via a pipeline and is used to perform vacuuming operations on the container 31. The pressure detection device 34 is disposed on the shroud 312 and is signal-connected to the vacuuming device to monitor the internal pressure inside the container 31 and to enable the vacuuming device to maintain the pressure inside the container 31 stable.

[0054] It should be noted that the vacuuming device is connected to the cover 312 via a pipeline to evacuate the container 31, ensuring a vacuum environment during the heating of waste materials such as waste resin or residual liquid, effectively preventing leakage of internal aerosols. A pressure detection device 34 is installed on the cover 312 to monitor the pressure inside the container 31 of the drying device 3 in real time. The pressure detection device 34 is connected to the vacuuming device, so when the pressure inside the container 31 is lower than the preset value, the vacuuming device continues to evacuate the container 31; when the pressure inside the container 31 is higher than the preset value, the vacuuming device releases some air or stops evacuating, ensuring stable negative pressure inside the container 31. The preset value is the minimum pressure value within the container 31 that effectively prevents leakage of internal aerosols under heating conditions. The pressure detection device 34 can be a pressure gauge.

[0055] In one embodiment of the present invention, as shown in FIG4, the nuclear waste treatment system further includes a liquid level detection device 35, which is disposed on the tank cover 312.

[0056] It should be noted that a liquid level detection device 35 is installed on the cover 312 to detect the height of the waste in the waste bin 311, so that workers can determine the volume of waste in the waste bin 311 based on the height of the waste. The liquid level detection device 35 can be an ultrasonic level gauge, or other types of liquid level detection devices 35. Any detection device capable of detecting the height of waste in the waste bin 311 is suitable for this technical solution, and no specific limitation is made here.

[0057] In one embodiment of the present invention, as shown in FIG4, the barrel cover 312 is provided with a cleaning water inlet 3123.

[0058] It should be noted that by providing a cleaning water inlet 3123 on the barrel cover 312, clean water can be supplied to the barrel cover 312 and the waste bin 311, so as to clean the inner wall of the barrel cover 312 and the agitator 33 with clean water.

[0059] In one embodiment of the present invention, as shown in Figures 3 and 5, the lifting device includes a lifting assembly and a base 8, the lifting assembly is connected to the base 8, and the waste bin 311 is disposed on the base 8; the heating structure includes a first heating element, which is disposed on the base 8.

[0060] It should be noted that the lifting device is located directly below the drying device 3; the lifting component can be a vertically installed telescopic cylinder, electric push rod, etc.; the fixed end of the lifting component can be set on the ground or on the assembly line track of the nuclear waste treatment system. The assembly line track can transport the empty waste bin 311 to the base 8 position, and the lifting component can drive the base 8 to lift the waste bin 311.

[0061] The lifting end of the lifting assembly (not shown in the figure) is connected to the base 8, and the waste bin 311 is disposed on the base 8. The first heating element can be disposed inside the base 8 to avoid leakage accidents. The first heating element can be a heating tube or a heating plate. The installation method of the first heating element can be as follows: a receiving cavity is opened inside the base 8, and the first heating element is disposed in the receiving cavity; or, a groove is opened on the side wall of the base facing the waste bin, and the first heating element is disposed in the groove. Of course, the first heating element can also be installed in the base 8 in other ways, which are not specifically limited here.

[0062] As an example, the conveyor rail transports an empty waste bin 311 to the base 8 of the lifting device. When drying is required, the lifting end of the lifting assembly extends to drive the base 8 and raise the waste bin 311 to form a sealed connection with the bin cover 312. Then, the waste inside the waste bin 311 is heated and dried from the bottom of the waste bin 311 by the first heating element. After the drying is completed, the lifting end of the lifting assembly shortens to lower the waste bin 311 through the base 8, so that the waste bin 311 can be removed from the base 8 to seal the solid residue inside the waste bin 311.

[0063] In one embodiment of the present invention, as shown in Figures 4 and 5, the container 31 further includes a positioning door 313, the positioning door 313 including two arc-shaped plates, the two arc-shaped plates being used to surround the waste bin 311 to position the waste bin 311; the heating structure further includes a second heating element, the second heating element being disposed on the arc-shaped plates.

[0064] It should be noted that the two arc-shaped plates of the positioning door 313 are used to position and hold the waste bin 311 during the drying operation. After the drying operation is completed, they are opened to release the waste bin 311, making it easier to remove the waste bin 311 containing only solid residue. The curvature of the arc-shaped plates corresponds to the circumferential sidewall of the waste bin 311, so that when the arc-shaped plates surround the waste bin 311, they can make close contact with the waste bin 311 to improve heat conduction efficiency. When the two arc-shaped plates surround the waste bin 311, they can cover at least a portion of the circumferential sidewall of the waste bin 311. In other words, when the two arc-shaped plates surround part of the structure of the waste bin 311, part of the structure of the waste bin 311 is not covered by the arc-shaped plates and is in an exposed state. When the two arc-shaped plates surround the entire structure of the waste bin 311, the entire circumferential sidewall of the waste bin 311 is covered by the arc-shaped plates.

[0065] The curved plates can be installed in the following ways: for example, the top ends of the two curved plates are connected to the bottom end of the cover 312, or the bottom ends of the two curved plates are connected to the base 8; one end of the two curved plates is rotatably connected by a hinge structure, and by rotating the two curved plates, the two curved plates can be closed or unfolded in the waste bin 311, as shown in Figures 4 and 5. Alternatively, the arc-shaped plate may not have a direct connection with the barrel cover 312 and the base 8. For example, a nuclear waste treatment system may include two horizontally arranged pushing devices, each connected to the outer wall of the arc-shaped plate. Before the drying operation, the lifting assembly drives the base 8 to raise the waste barrel 311 and seal it with the barrel cover 312. Then, the two horizontal pushing devices drive the corresponding arc-shaped plates to move towards each other in the horizontal direction until they are circumferentially positioned and hold the waste barrel 311 tightly. After the drying operation is completed, the two horizontal pushing devices drive the corresponding arc-shaped plates to move away from each other in the horizontal direction until they unfold and release the waste barrel 311. The lifting assembly drives the base 8 to lower the waste barrel 311 away from the barrel cover 312 so that the waste barrel 311 containing only solid residue can be removed. In this embodiment, the horizontal pushing device may be a horizontally arranged telescopic cylinder, telescopic air cylinder, electric push rod, etc., which are not specifically limited here.

[0066] The second heating element can be positioned relative to the arc-shaped plate in the following ways: a groove is formed on the inner wall of the arc-shaped plate facing the waste bin 311, and the second heating element is embedded in the groove; or, a receiving cavity is formed inside the arc-shaped plate, and the second heating element is placed in the receiving cavity. The arc-shaped plate is made of a heat-conducting material, so that when the arc-shaped plate approaches and positions itself to hold the waste bin 311, the second heating element can quickly conduct heat through the arc-shaped plate to the side of the waste bin 311 to heat and dry the waste inside the waste bin 311.

[0067] For example, before the drying operation, an empty waste bin 311 is conveyed to the base 8. Then, a lifting assembly operates to drive the base 8, raising the waste bin 311 to a sealed connection with the bin cover 312. Two arc-shaped plates surround the waste bin 311 to position it. After waste is poured into the waste bin 311, a second heating element located within the arc-shaped plates and a first heating element located on the base 8 are activated to generate heat, thereby heating and drying the waste inside the waste bin 311 from its circumferential sidewalls and bottom. After the drying operation is completed, the two arc-shaped doors release the waste bin 311. The lifting assembly then operates to drive the base 8, lowering the waste bin 311 away from the bin cover 312. Finally, the waste bin 311, containing only solid residue, is removed from the base 8.

[0068] In one embodiment of the present invention, as shown in FIG6, the drive assembly 32 includes a first drive device 321 and a second drive device 322, and the stirring assembly 33 includes a first rotating shaft 331, a second rotating shaft 332, a commutator group 333, and a stirrer 334. The first drive device 321 is drivenly connected to one end of the first rotating shaft 331, and the end of the first rotating shaft 331 away from the first drive device 321 is connected to the housing of the commutator group 333. The second rotating shaft 332 is embedded in the first rotating shaft 331, and the second drive device 322 is drivenly connected to one end of the second rotating shaft 332. The end of the second rotating shaft 332 away from the second drive device 322 is connected to the input gear of the commutator group 333, and the output gear of the commutator group 333 is connected to the stirrer 334.

[0069] It should be noted that the fixed end of the first driving device 321 can be set on the lifting frame 37. The driving end of the first driving device 321 can be connected to one end of the first rotating shaft 331, such as the top end, through a gear transmission assembly. Since the end of the first rotating shaft 331 away from the first driving device 321, such as the bottom end, is connected to the housing of the commutator group 333, the first driving device 321 can drive the first rotating shaft 331 to drive the commutator group 333 to rotate. The commutator group 333 is connected to the agitator 334, so that the first rotating shaft 331 drives the agitator 334 to revolve around the central axis of the container 31 through the commutator group 333, thereby realizing the rotational agitation operation of the waste in the container 31. At this time, the housing of the commutator group 333 is used to transmit the revolution torque of the first rotating shaft 331. The gear transmission assembly includes a gear carrier and a drive gear and a transmission gear mounted on the gear carrier. The drive shaft of the first drive device 321 is driven to the center of the drive gear. The drive gear is meshed with the transmission gear. The top end of the first rotating shaft 331 passes through the transmission gear. At this time, the rotation of the first drive device 321 can drive the rotation of the first rotating shaft 331 through the drive gear and the transmission gear.

[0070] The first rotating shaft 331 is a hollow shaft so that the second rotating shaft 332 can be embedded inside the first rotating shaft 331. The fixed end of the second driving device 322, for example, the outer shell, is mounted on the lifting frame 37. The driving end of the second driving device 322, for example, the driving shaft, is connected to the top end of the second rotating shaft 332. The end of the second rotating shaft 332 away from the second driving device 322, for example, the bottom end, is connected to the input gear of the commutator group 333. The output gear of the commutator group 333 is connected to the agitator 334. Thus, the second rotating shaft 332 is driven to rotate by the second driving device 322. By changing the input gear and the output gear of the commutator group 333, the agitator 334 is driven to rotate, so as to perform up-and-down turning operation on the waste in the waste bin 311. At this time, the input gear and the output gear of the commutator group 333 are used to transmit the rotational torque of the second rotating shaft 332 to the agitator 334. The first driving device 321 and the second driving device 322 mentioned above can be a rotary motor, a rotary cylinder that can provide rotational force, etc., and are not specifically limited here. In Figure 5, the annular arrow at the first rotating shaft of the stirring assembly 33 indicates the rotation direction of the first rotating shaft, and the annular arrow at the second rotating shaft indicates the rotation direction of the second rotating shaft.

[0071] As shown in Figure 6, the commutator assembly 333 includes a housing and four bevel gears, which are defined as a first bevel gear, a second bevel gear, a third bevel gear, and a fourth bevel gear. The bottom end of the second rotating shaft 332 is connected to the first bevel gear, and the first bevel gear meshes with the second bevel gear, so that the second bevel gear can change the rotation and torque direction of the first bevel gear and the second rotating shaft 332. The third bevel gear is connected to the second bevel gear through a horizontally arranged connecting rod, and the fourth bevel gear meshes with the third bevel gear. The fourth bevel gear is connected to the top end of the agitator 334 and is used to change the rotation and torque direction of the third bevel gear and the second bevel gear, so that the torque direction of the agitator 334 corresponds to the torque direction of the second rotating shaft 332.

[0072] The agitator 334 can be a screw agitator 334. Through the rotation of the agitator 334, the waste material in the container 31 can be turned upside down. The first rotating shaft drives the agitator to revolve around the central axis of the container, and the waste material, such as waste resin, is rotated and stirred in a heated environment. The second rotating shaft and the commutator group drive the agitator to rotate, and the waste resin is turned upside down in a heated environment. This makes the drying process of the waste resin in a heated environment more uniform and faster, and further improves the drying quality and efficiency of the waste resin.

[0073] In one embodiment of the present invention, the driving component 32 includes a third driving device, and the stirring component 33 includes a ribbon stirring shaft. The third driving device is drivenly connected to the ribbon stirring shaft and is used to drive the ribbon stirring shaft to rotate.

[0074] It should be noted that, unlike the embodiments described above, this embodiment uses only one driving device as the power source. The fixed end of the third driving device can be mounted on the lifting frame 37, and the driving end of the third driving device is connected to the spiral ribbon stirring shaft, thereby driving the spiral ribbon stirring shaft to rotate and achieve the up-and-down tumbling action of the waste material in the container 31. This makes the waste resin more evenly heated during the up-and-down tumbling process, preventing the waste resin at the bottom of the container from drying while the waste resin at the top remains undried, thus improving the drying effect of the waste resin. The third driving device can also be a rotary motor, a rotary cylinder that can provide rotational force, etc., and is not specifically limited here.

[0075] Another embodiment of the present invention provides a method for treating nuclear power waste, based on the nuclear power waste treatment system described above, and comprising the following steps:

[0076] S1. The waste resin in the waste resin temporary storage device 1 or the residual liquid in the residual liquid temporary storage device 2 is respectively transported to the drying device 3.

[0077] Therefore, waste resin in waste resin temporary storage device 1 can be transported to drying device 3 through pipeline by a water pump, and residual liquid in residual liquid temporary storage device 2 can be transported to drying device 3 through pipeline by another water pump, thereby providing a more sufficient source of waste material for subsequent heating and drying operations of different waste materials such as waste resin or residual liquid through the same drying device 3.

[0078] S2. Control the drying device 3 to perform corresponding drying operations on the waste resin or the residual liquid inside it. The high-temperature water vapor generated during the drying operation is discharged from the exhaust port 3122 of the drying device 3 and transported to the cooling device 4.

[0079] Therefore, when the waste resin enters the drying device 3, the drying device 3 performs up-and-down turning and rotating stirring operations on the waste resin in the container 31 under a heated environment, so that the waste resin can be dried evenly, thereby accelerating the drying process of the waste resin; during the drying process, high-temperature water vapor is generated, and then the high-temperature water vapor enters the cooling device 4 along the pipeline.

[0080] After the residual liquid enters the drying device 3, the drying device 3 heats and dries the residual liquid in the container 31; during the drying process, high-temperature water vapor is generated, and then the high-temperature water vapor enters the cooling device 4 along the pipeline.

[0081] During the drying process, high-temperature steam of about 200 degrees Celsius is generated in the container 31 of the drying device 3 and discharged from the exhaust port 3122 on the barrel cover 312. Since the high-temperature steam may contain flammable gas, which may easily cause a risk of combustion and explosion, the high-temperature steam will pass through the flammable gas detection device 6 and the flame retardant device 7 in sequence. If the flammable gas detection device 6 detects that the content of flammable gas exceeds the detection value and the set value, the flame retardant device 7 will be activated. At this time, the flame retardant device 7 fills the container 31 of the drying device 3 with inert gas to avoid the risk of combustion and explosion. If the flammable gas detection device 6 detects that the content of flammable gas does not exceed the detection value and the set value, it can be directly transferred to the cooling device 4.

[0082] After the drying process is completed, solid residue will remain in the waste bin 311. At this time, the solid residue in the waste bin 311 can be sealed.

[0083] S3. Cooling equipment 4 is turned on to generate a low-temperature medium to condense the high-temperature water vapor and generate waste gas and waste liquid.

[0084] Therefore, a low-temperature medium, such as cold water, is provided by the cooling device 4 to cool the high-temperature water vapor to form waste gas and waste liquid. Since the waste water and waste liquid may have a certain degree of radioactivity, they are subsequently treated by the waste gas treatment device 51 and the waste liquid treatment device 52 respectively, so as to avoid the waste gas and waste liquid from polluting the air.

[0085] S4 and the waste gas and waste liquid treatment equipment 5 treat the waste gas and the waste liquid respectively.

[0086] Therefore, the waste gas and waste liquid treatment equipment 5 includes a waste gas treatment device 51 and a waste liquid treatment device 52. The waste gas and waste liquid formed after being cooled by the cooling device 4 enter the waste gas treatment device 51 and the waste liquid treatment device 52 respectively, so that the waste gas treatment device 51 and the waste liquid treatment device 52 can perform harmless treatment on the waste gas and waste liquid respectively, thereby effectively reducing the pollution to the environment.

[0087] In one embodiment of the present invention, S2, controlling the drying device 3 to perform corresponding drying operations on the waste resin or the residual liquid inside it includes:

[0088] S21. When the waste material entering the container 31 of the drying device 3 is the waste resin: the container 31 is vacuumed; the stirring component 33 of the drying device 3 descends and penetrates into the waste tank 311 of the container 31, and the waste resin in the waste tank 311 is stirred in a heated environment.

[0089] Therefore, the drying process for waste resin is as follows: When the empty waste barrel 311 is conveyed or placed on the base 8 of the lifting assembly, the lifting assembly operates to drive the waste barrel 311 to rise and seal with the barrel cover 312, closing the two positioning doors 313 to enclose the waste barrel 311; the lifting assembly 36 operates to drive the lifting frame 37 to lower the stirring assembly 33, and then the drive assembly 32 is activated to make the stirring assembly 33 move; the waste resin in the waste resin temporary storage device 1 is transported to the waste barrel 311 by a water pump, and the addition stops when the liquid level signal of the waste barrel 311 is reached; the cooling device 4 operates to generate a circulating low-temperature medium; the vacuum device is activated to create a negative pressure environment in the stirring chamber of the drying device 3 to prevent aerosols inside the container 31. The heating structure of the drying device 3 is activated to heat and dry the waste resin in the waste barrel 311. After the initial addition of material is dried, waste resin is added to the waste barrel 311 until the solid residue in the waste barrel 311 meets the filling height requirement and then stops. After the stirring operation is completed, the heating structure stops. After the internal temperature of the drying device 3 drops to a safe temperature, the drive component 32 stops working, and the lifting component 36 drives the lifting frame 37 to lift the drive component 32 and the stirring component 33 away from the waste barrel 311. The cooling device 4 is turned off. The vacuum device is turned off, and the lifting component works to drive the waste barrel 311 to descend away from the barrel cover 312. Then the waste barrel 311 is removed and the solid residue inside is sealed.

[0090] S22. When the waste material entering the container 31 of the drying device 3 is the residual liquid from evaporation: the container 31 is evacuated; the stirring component 33 of the drying device 3 is lifted and detached from the waste bin 311 of the container 31, and the residual liquid from evaporation in the waste bin 311 is heated.

[0091] Therefore, the drying process of the residual liquid is basically the same as that of the waste resin. The difference is that the drying process of the residual liquid does not require the stirring of the stirring component 33. Throughout the drying process, the stirring component 33 connected to the drive component 32 is kept at a high position in the drying device 3, that is, inside the barrel cover 312 above the waste barrel 311, and remains stationary. The reason why the stirring component 33 does not work during the entire drying process of the residual liquid is that after the residual liquid is dried, the salt inside will crystallize into crystals. Therefore, the stirring component 33 does not need to work. The heat can be transferred to the residual liquid in the waste barrel 311 by the first heating element in the base 8 and the second heating element in the arc plate, and the salt is controlled to gradually crystallize from the bottom of the waste barrel 311 upwards.

[0092] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A nuclear power waste treatment system, characterized in that, The system includes a waste resin storage device (1), a residual liquid storage device (2), a drying device (3), a cooling device (4), and a waste gas and waste liquid treatment device (5). The inlet (3121) of the drying device (3) is connected to the outlets of the waste resin storage device (1) and the residual liquid storage device (2), respectively, for drying the waste resin and the residual liquid. The cooling device (4) is connected to the exhaust port (3122) of the drying device (3) to condense the high-temperature water vapor discharged from the exhaust port (3122) of the drying device (3). The waste gas and waste liquid treatment device (5) is connected to the cooling device (4) to cool the waste resin and the residual liquid. The waste gas and waste liquid generated after condensation are treated; the drying device (3) includes a container (31), a heating structure, a driving component (32), and a stirring component (33). The heating structure is disposed on the side of the container (31). The driving component (32) is connected to one end of the stirring component (33) to drive the stirring component (33) to rotate. The stirring component (33) is at least partially disposed inside the container (31) to perform up-and-down flipping and rotation stirring of the waste material inside the container (31). It also includes a lifting device. The container (31) includes a waste bucket (311) and a bucket cover (312). The bucket cover (312) and the waste bucket (311) are aligned along the... The container (31) is arranged along its central axis. The barrel cover (312) is a hollow cylindrical structure with an open bottom. The lifting device is connected to the waste bin (311) and is used to drive the waste bin (311) to rise and seal with the bottom opening of the cylindrical structure to form a stirring chamber. The stirring assembly (33) passes through the barrel cover (312) and is located in the stirring chamber. The barrel cover (312) is provided with the inlet (3121) and the exhaust port (3122). The drying device (3) also includes a lifting assembly (36) and a lifting frame (37). The driving assembly (32) is located on the lifting frame (37), and the stirring assembly (33) is located far from the center axis. One end of the drive assembly (32) passes through the lifting frame (37) and the barrel cover (312). The lifting assembly (36) is disposed on the side wall of the barrel cover (312). The lifting end of the lifting assembly (36) is connected to the lifting frame (37) and is used to drive the lifting frame (37) to drive the stirring assembly (33) to penetrate or disengage from the waste barrel (311) through the drive assembly (32). The lifting device includes a lifting assembly and a base (8). The lifting assembly is connected to the base (8). The waste barrel (311) is disposed on the base (8). The heating structure includes a first heating element, which is disposed on the base (8).

2. The nuclear waste treatment system according to claim 1, characterized in that, The container (31) further includes a positioning door (313), which includes two arc-shaped plates for surrounding the waste bin (311) to position the waste bin (311); the heating structure further includes a second heating element disposed on the arc-shaped plates.

3. The nuclear waste treatment system according to claim 1 or 2, characterized in that, The drive assembly (32) includes a first drive device (321) and a second drive device (322). The stirring assembly (33) includes a first rotating shaft (331), a second rotating shaft (332), a commutator group (333), and a stirrer (334). The first drive device (321) is driven connected to one end of the first rotating shaft (331), and the end of the first rotating shaft (331) away from the first drive device (321) is connected to the housing of the commutator group (333). The second rotating shaft (332) is embedded in the first rotating shaft (331), and the second drive device (322) is driven connected to one end of the second rotating shaft (332). The end of the second rotating shaft (332) away from the second drive device (322) is connected to the input gear of the commutator group (333), and the output gear of the commutator group (333) is connected to the stirrer (334).

4. The nuclear waste treatment system according to claim 1 or 2, characterized in that, The drive assembly (32) includes a third drive device, and the stirring assembly (33) includes a ribbon stirring shaft. The third drive device is driven to the ribbon stirring shaft and is used to drive the ribbon stirring shaft to rotate.

5. A method for treating nuclear waste, based on the nuclear waste treatment system as described in any one of claims 1 to 4, characterized in that, The following steps are adopted: the waste resin in the waste resin temporary storage device (1) or the residual liquid in the residual liquid temporary storage device (2) is respectively transported to the drying device (3); the drying device (3) is controlled to perform corresponding drying operations on the waste resin or the residual liquid inside it, and the high temperature water vapor generated in the drying operation is discharged from the exhaust port (3122) of the drying device (3) and transported to the cooling device (4); the cooling device (4) is turned on to generate a low temperature medium to condense the high temperature water vapor and generate waste gas and waste liquid; the waste gas and waste liquid treatment device (5) treats the waste gas and the waste liquid respectively.

6. The nuclear waste treatment method according to claim 5, characterized in that, The control of the drying device (3) to perform corresponding drying operations on the waste resin or the residual liquid inside it includes: when the waste material entering the container (31) of the drying device (3) is the waste resin: vacuuming the container (31); the stirring component (33) of the drying device (3) descends and penetrates into the waste tank (311) of the container (31), and the waste resin in the waste tank (311) is stirred in a heated environment; when the waste material entering the container (31) of the drying device (3) is the residual liquid: vacuuming the container (31); the stirring component (33) of the drying device (3) rises and detaches from the waste tank (311) of the container (31), and the residual liquid in the waste tank (311) is heated.

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