Filtrate receiving system, method and facility for continuously filtering radioactive materials

Abstract

The invention discloses a filtrate receiving system for continuously filtering radioactive materials, which is arranged at a continuous filtering device and comprises a filtrate receiving device, an intermediate container, a vacuum power device and a communicating pipeline, the filtrate receiving device is communicated with the continuous filtering device through the communicating pipeline, and a cavity is formed in the intermediate container; the cavity is communicated with the communicating pipeline, the vacuum power device is communicated with the middle container and applies negative pressure to the cavity in the middle container, so that filtrate generated by the continuous filtering device is sucked into the communicating pipeline through suction force formed by the negative pressure, and then the filtrate is continuously conveyed to the filtrate receiving device through the communicating pipeline. According to the system, filtrate can be guided out at any time under the condition that continuous negative pressure is provided for continuous filtration, required parts are simple, and the fault rate, the operation difficulty and the cost are effectively reduced. The invention further provides a filtrate receiving method and facility for continuously filtering the radioactive materials.

Description

Technical Field

[0001] The present invention specifically relates to a filtrate receiving system, method and facility for continuous filtration of radioactive materials. Background Art

[0002] The plutonium tail-end process is an important process in the nuclear industry field. The commonly used method is to convert plutonium nitrate into plutonium oxalate slurry through a precipitation reaction. After the plutonium oxalate slurry is filtered, plutonium oxalate filter cake and filtrate are separated. Then, the filter cake is dried and calcined to decompose plutonium oxalate (filter cake) into plutonium dioxide. There are still a small amount of un-precipitated plutonium ions in the filtrate obtained after filtering the plutonium oxalate slurry, and there may also be a small amount of incompletely filtered plutonium oxalate particles. Due to the particularity of plutonium materials, strict control of plutonium is required, that is, the plutonium in the filtrate needs to be recovered to the treatment system for re-treatment, rather than directly discharging the plutonium-containing filtrate as waste liquid. Therefore, the filtrate receiving device is particularly important for the plutonium tail-end process.

[0003] At present, most of the filtration devices in the plutonium tail-end process adopt batch-type equipment and processes. The batch-type equipment filtration adopts the method of compressed air + suction filtration, and the filtrate receiving device provides the vacuum power for suction filtration. Therefore, the filtrate receiving device needs to provide negative pressure, and when returning the filtrate of the filtrate receiving device to the system, normal pressure or positive pressure is required. Therefore, the filtrate receiving device involves the switching between positive and negative pressures, and valves are inevitably used in the switching process.

[0004] However, the filtrate receiving device is in a radioactive environment containing plutonium, and ordinary valves cannot be used. Instead, a special ground-penetrating valve for the radioactive environment needs to be used. The ground-penetrating valve for the radioactive environment needs to be equipped with a special maintenance container for maintenance. The maintenance container of the ground-penetrating valve needs to be shielded, which is not only very large in shape but also occupies a large maintenance space. Moreover, the valve stem penetrates the equipment room, with poor reliability and high cost; once the ground-penetrating valve fails, the operation of the filtration device and the receiving device needs to be stopped to facilitate the maintenance and replacement of the ground-penetrating valve, and the cycle is long, affecting the overall starting rate of the plutonium tail-end. In addition, the filtrate receiving device not only involves the positive and negative pressure switching pipelines, but also has pipelines for washing, feeding, etc. Usually, a set of filtrate receiving devices needs to be equipped with multiple ground-penetrating valves.

[0005] For the continuous filtration process, the filtrate receiving device is also required to provide vacuum, but because the filtration is continuous, the negative pressure needs to be maintained at the filtrate receiving device at all times. However, the filtrate receiving device cannot be infinitely large. The filtrate needs to be discharged after a period of time, and the continuous filtration process cannot be stopped, so at least two sets of filtrate receiving devices need to be set up, one to maintain the negative pressure required for continuous filtration, and one to switch to normal pressure or positive pressure to export the filtrate. Moreover, for the continuous filtration process, it may involve processes such as filtration, washing, filtrate drying, and filter plate regeneration. Each process requires different negative pressures and suction capacities provided by the filtrate receiving device, and multiple sets of filtrate receiving devices may be required. In this way, the number of equipment, pipelines, and ground-penetrating valves required for the device will increase exponentially, and the operation will be complicated, which is extremely unfavorable for production; and the cost is high, the failure rate is high, the floor space is large, and the economy is very poor. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a filtrate receiving system for continuous filtration of radioactive materials in view of the above-mentioned deficiencies in the prior art. The system can export the filtrate at any time while providing continuous negative pressure for continuous filtration, and the required components are simple, effectively reducing the failure rate, operation difficulty and cost. The present invention also provides a filtrate receiving method and facility for continuous filtration of radioactive materials.

[0007] The present invention provides a filtrate receiving system for continuous filtration of radioactive materials, which is arranged at a continuous filtration device and includes a filtrate receiving device, an intermediate container, a vacuum power device and a connecting pipe. The filtrate receiving device is connected to the continuous filtration device through the connecting pipe. The intermediate container has a cavity inside, and the cavity is connected to the connecting pipe. The vacuum power device is connected to the intermediate container and applies negative pressure to the cavity in the intermediate container, so that the filtrate generated by the continuous filtration device is sucked into the connecting pipe by the suction force formed by the negative pressure, and then continuously transported to the filtrate receiving device through the connecting pipe.

[0008] Furthermore, the filtrate receiving device is located below the continuous filtering device and the intermediate container, and the filtrate sucked into the connecting pipe is continuously transported to the filtrate receiving device through the connecting pipe under the action of gravity.

[0009] Furthermore, the connecting pipe includes a feed pipe and a discharge pipe, the feed pipe connects the top of the intermediate container and the continuous filtering device, the discharge pipe connects the bottom of the intermediate container and the filtrate receiving device, the vacuum power device applies negative pressure to the intermediate container, so that the gas-containing filtrate enters the cavity in the intermediate container through the feed pipe, and completes the separation of gas and filtrate under the action of gravity, the upper gas is extracted by the vacuum power device, and the lower filtrate enters the filtrate receiving device through the discharge pipe.

[0010] Further, the connecting pipe includes a feed pipe, a discharge pipe, and an air inlet pipe. The intermediate container is located above the continuous filtration device. The discharge pipe connects the bottom of the intermediate container and the filtrate receiving device. The feed pipe connects the top of the discharge pipe and the continuous filtration device. The air inlet pipe is a pipe that branches upward from the feed pipe and is connected to the top of the intermediate container. The vacuum power device applies a negative pressure to the intermediate container, so that the negative pressure generated in the air inlet pipe draws the filtrate to enter the discharge pipe through the feed pipe and then enter the filtrate receiving device through the discharge pipe.

[0011] Further, the inner diameter of the discharge pipe is larger than that of the feed pipe.

[0012] Further, the height difference in the vertical direction between the filtrate receiving device and the continuous filtration device is not less than 6m.

[0013] Further, the system further includes a first control unit. A first liquid level monitoring device is provided on the intermediate container for monitoring the liquid level in the intermediate container. The first control unit is electrically connected to the first liquid level monitoring device and the vacuum power device respectively, and is used to adjust the magnitude of the negative pressure provided by the vacuum power device when the liquid level in the intermediate container exceeds the first set liquid level.

[0014] Further, the filtrate receiving device includes a filtrate receiving tank. The filtrate receiving tank contains liquid. The port of the connecting pipe connected to the filtrate receiving device extends below the liquid level of the liquid in the filtrate receiving tank to form a liquid seal for the filtrate.

[0015] Further, the system further includes a second control unit. The filtrate receiving device further includes a second liquid level monitoring device for monitoring the liquid level in the filtrate receiving tank. The filtrate receiving tank is connected to an external filtrate treatment device. The second control unit is electrically connected to the second liquid level monitoring device and the filtrate receiving tank respectively, and is used to transfer the filtrate from the filtrate receiving tank to the filtrate treatment device when the liquid level in the filtrate receiving tank exceeds the second set liquid level, and generate an alarm signal when the liquid level in the filtrate receiving tank is lower than the third set liquid level. The second set liquid level is higher than the third set liquid level.

[0016] Further, the system further includes a third control unit and a dissolution liquid adding device. The dissolution liquid adding device is connected to the filtrate receiving tank. The filtrate receiving device further includes a component monitoring device for monitoring the content of the component to be filtered in the filtrate receiving tank. The third control unit is electrically connected to the component monitoring device and the dissolution liquid adding device respectively, and is used to control the dissolution liquid adding device to add dissolution liquid into the filtrate receiving tank when the content of the component to be filtered in the filtrate receiving tank exceeds the set content to dissolve the component to be filtered.

[0017] Further, the vacuum power device applies negative pressure to the intermediate container by sucking gas. The vacuum power device includes a trap, a scrubber tank, a regulating device, and a vacuum pump. The trap is connected to the cavity inside the intermediate container. The scrubber tank, the regulating device, and the vacuum pump are sequentially connected downstream of the trap. The trap is used to trap the particles to be filtered in the gas. The scrubber tank is used to wash and remove the aerosol to be filtered and acid gas in the gas. The regulating device is used to adjust the pressure and flow rate of the vacuum pump. The vacuum pump is used to provide negative pressure and discharge the sucked gas to the external tail gas treatment device.

[0018] Further, the system further includes a fourth control unit. Taking a group of intermediate containers, a vacuum power device, and a connecting pipe connected between the continuous filtration device and the filtrate receiving device as a receiving module, there are multiple groups of the receiving modules. Each receiving module is connected between the continuous filtration device and the filtrate receiving device in parallel. The fourth control unit is electrically connected to the continuous filtration device and each receiving module respectively, and is used to control the conduction of the set receiving module according to the set requirements of the continuous filtration device.

[0019] The present invention also provides a method for receiving filtrate for continuous filtration of radioactive materials, using the above-mentioned filtrate receiving system for continuous filtration of radioactive materials. The method includes the following steps:

[0020] Turn on the vacuum power device to apply negative pressure to the cavity inside the intermediate container;

[0021] The suction force formed by the negative pressure in the cavity of the intermediate container sucks the filtrate generated by the continuous filtration device into the connecting pipe, and then continuously transports it to the filtrate receiving device through the connecting pipe.

[0022] The present invention also provides a radioactive material continuous filtration facility, including a continuous filtration device, a filtrate treatment device, and the above-mentioned filtrate receiving system for continuous filtration of radioactive materials. The continuous filtration device is used to filter radioactive materials and generate filtrate; the filtrate receiving system for continuous filtration of radioactive materials is connected between the continuous filtration device and the filtrate treatment device, and is used to receive the filtrate generated by the continuous filtration device and transfer the material to the filtrate treatment device; the filtrate treatment device is used to treat the filtrate.

[0023] The filtrate receiving system for continuous filtration of radioactive materials of the present invention sucks and drives the filtrate to continuously transport along the connecting pipeline to the filtrate receiving device by the suction force formed by the negative pressure in the intermediate container. The filtrate receiving device itself does not provide the negative pressure suction force for the transportation of the filtrate. It can be seen that this system innovatively eliminates the dependence on the internal pressure of the filtrate receiving device. Therefore, when the filtrate receiving device does not need to undertake the suction function, any feasible measures can be taken when transferring the filtrate back to the system, without involving the conversion of positive and negative pressures. Not only is the operation simpler, but also the use of underground valves can be avoided. The required components are simple, effectively reducing the failure rate and layout cost. And precisely because the filtrate receiving device does not need to undertake the suction function, the filtration and reception are pressure decoupled. Therefore, the filtrate can be exported at any time during the process of the continuous filtration device generating the filtrate, without the need to separately set up two sets of equipment to perform extraction and export respectively, and the volume requirement for the receiving device is lower, the floor area is smaller, and the economy is better. Brief Description of the Drawings

[0024] Figure 1 It is a schematic structural diagram of the filtrate receiving system for continuous filtration of radioactive materials in Embodiment 1 of the present invention.

[0025] In the figure: 1. Continuous filtration device; 2. Filtrate receiving device; 21. Filtrate receiving tank; 22. Second liquid level monitoring device; 23. Component monitoring device; 3. Intermediate container; 31. First liquid level monitoring device; 4. Vacuum power device; 41. Trapper; 42. Scrubbing tank; 43. Adjusting device; 44. Vacuum pump; 5. Connecting pipeline; 51. Feed pipeline; 52. Discharge pipeline; 53. Intake pipeline; 6. Filtrate treatment device; 7. Dissolved liquid adding device; 8. Tail gas treatment device. Detailed Embodiments

[0026] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of the present invention.

[0027] In the description of the present invention, it should be noted that the terms "upper", "lower", etc. indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0028] In the description of the present invention, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connect", "set", "install", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0030] Example 1

[0031] like Figure 1 As shown, the filtrate receiving system for continuous filtration of radioactive materials of this embodiment can be used in the field of nuclear fuel reprocessing technology, specifically in the plutonium tail end continuous filtration process, and can be said to be a maintenance-free filtrate receiving system for continuous filtration in a reprocessing plant.

[0032] The system is arranged at a continuous filtering device 1, and includes a filtrate receiving device 2, an intermediate container 3, a vacuum power device 4 and a connecting pipe 5. The filtrate receiving device 2 is connected to the continuous filtering device 1 through the connecting pipe 5. The intermediate container 3 has a cavity inside, and the cavity is connected to the connecting pipe 5. The vacuum power device 4 is connected to the intermediate container 3 and applies negative pressure to the cavity in the intermediate container 3, so that the filtrate generated by the continuous filtering device 1 is sucked into the connecting pipe 5 by the suction force formed by the negative pressure, and then continuously transported to the filtrate receiving device 2 through the connecting pipe 5.

[0033] The filtrate receiving system for continuous filtration of radioactive materials in this embodiment uses the suction force formed by the negative pressure in the intermediate container 3 to suck and drive the filtrate to be continuously transported along the connecting pipe 5 to the filtrate receiving device 2. The filtrate receiving device 2 itself does not provide negative pressure suction force for the transportation of the filtrate. It can be seen that this system innovatively eliminates the dependence on the internal pressure of the filtrate receiving device 2.

[0034] Therefore, when the filtrate receiving device 2 does not need to assume the suction function, any feasible measures can be taken when transferring the filtrate back to the system, without involving the conversion of positive and negative pressures. Not only is the operation easier, but the use of ground-penetrating valves can also be avoided, the required components are simple, and the failure rate and layout cost are effectively reduced. At the same time, the inconvenience that may be introduced by the use of ground-penetrating valves is avoided, such as avoiding the problem of equipment shutdown and low operating rate caused by replacement of ground-penetrating valve failures, and achieving maintenance-free connection of the pipeline 5 and the filtrate receiving device 2.

[0035] And precisely because the filtrate receiving device 2 does not need to assume the suction function, filtration and receiving are pressure decoupled, so the filtrate can be discharged at any time during the process of the continuous filtration device 1 producing filtrate, and there is no need to set up two sets of equipment separately to perform extraction and discharge respectively. The volume requirement of the filtrate receiving device 2 is also lower, the overall system occupies a smaller area, and is more economical.

[0036] In this embodiment, the filtrate receiving device 2 is located below the continuous filtration device 1 and the intermediate container 3. The filtrate suctioned into the connecting pipe 5 is continuously transported to the filtrate receiving device 2 via the connecting pipe 5 under the action of gravity. This setting allows the filtrate in the connecting pipe 5 to flow naturally to the filtrate receiving device 2 by gravity, further avoiding the need for negative pressure, not only reducing energy consumption, but also being able to naturally suppress the backflow in the pipe by the hydrostatic pressure formed by the high-level difference. Moreover, the inside of the filtrate receiving device 2 itself does not need to maintain a specific pressure environment and can always maintain an open state at normal pressure during the receiving process. This design enables the device to directly perform operations such as filtrate transfer without configuring a complex pressure regulation system, which not only simplifies the equipment complexity, but also provides a flexible operation space for the post-treatment process of radioactive filtrate, ensuring the safe operation of the entire system under the condition of no back pressure at the receiving end.

[0037] In this embodiment, the height difference between the filtrate receiving device 2 and the continuous filtration device 1 in the vertical direction is not less than 6 m, and the height difference can be set between 6 m and 10 m, or slightly higher than 10 m, so as to form sufficient static pressure head by using gravitational potential energy to ensure that the filtrate flows by gravity to the filtrate receiving device 2.

[0038] In this embodiment, a set of intermediate containers 3, vacuum power devices 4, and connecting pipes 5 connected between the continuous filtration device 1 and the filtrate receiving device 2 are defined as a set of receiving modules. Then, there are two types of receiving modules corresponding to the flow route of the filtrate in the connecting pipe 5. The filtrate receiving system for continuous filtration of radioactive materials further includes a fourth control unit, and the fourth control unit selects one of the types of receiving modules to conduct according to the filtrate situation generated by the continuous filtration device 1.

[0039] Specifically, the first type of route receiving module is used for sucking a mixture of gas and liquid as the filtrate, such as Figure 1 the connecting pipe 5 and the vacuum power device 4 connected to the intermediate container 3 on the left side in [diagram]. Among them, the connecting pipe 5 includes a feed pipe 51 and a discharge pipe 52. The feed pipe 51 connects the top of the intermediate container 3 and the continuous filtration device 1, and the discharge pipe 52 connects the bottom of the intermediate container 3 and the filtrate receiving device 2. The vacuum power device 4 provides negative pressure for the intermediate container 3, and the pressure is not higher than -40 kPa. The vacuum power device 4 applies negative pressure to the intermediate container 3, so that the gas-containing filtrate enters the cavity in the intermediate container 3 through the feed port at the top via the feed pipe 51, and the gas and filtrate are separated under the action of gravity. The upper gas is evacuated by the vacuum power device 4, and the lower filtrate enters the filtrate receiving device 2 via the discharge pipe 52.

[0040] The second type of route receiving module is used for sucking continuous filtrate, that is, the liquid in the pipe fills the pipe or is close to filling the pipe, such as Figure 1The communicating pipe 5 and the vacuum power device 4 connected to the middle container 3 on the right side in the middle, wherein the communicating pipe 5 includes a feed pipe 51, a discharge pipe 52 and an air inlet pipe 53. The middle container 3 is located above the continuous filtration device 1. The discharge pipe 52 communicates with the bottom of the middle container 3 and the filtrate receiving device 2. The feed pipe 51 communicates with the top of the discharge pipe 52 and the continuous filtration device 1. The air inlet pipe 53 is a pipe branched upward from the feed pipe 51 and communicated to the top (feed port) of the middle container 3. The vacuum power device 4 provides a negative pressure for the middle container 3, and the pressure is not higher than -40 kPa. The vacuum power device 4 applies a negative pressure to the middle container 3, and the negative pressure extends into the air inlet pipe 53 through the feed port at the top of the middle container 3, so that the negative pressure generated in the air inlet pipe 53 draws the filtrate to enter the discharge pipe 52 through the feed pipe 51, and makes the communicating pipe 5 (feed pipe 51, discharge pipe 52) between the continuous filtration device 1 and the filtrate receiving device 2 filled with liquid, forming a path similar to siphon. No liquid enters the middle container 3, and the filtrate directly enters the filtrate receiving device 2, and the gas is discharged through the middle container 3 to the vacuum power device 4.

[0041] In this embodiment, the inner diameter of the discharge pipe 52 is larger than that of the feed pipe 51, and should be at least one to two specifications larger than the feed pipe 51. For example, if the feed pipe 51 is DN15, the discharge pipe 52 can be DN25. The discharge pipe 52 is designed with a larger pipe diameter than the feed pipe 51, which can ensure that the system remains unobstructed during long-term operation and reduce the maintenance frequency.

[0042] In this embodiment, the filtrate receiving system for continuous filtration of radioactive materials further includes a first control unit. A first liquid level monitoring device 31 is provided on the middle container 3 for monitoring the liquid level in the middle container 3. The first control unit is electrically connected to the first liquid level monitoring device 31 and the vacuum power device 4 respectively, and is used to adjust the magnitude of the negative pressure (or vacuum) provided by the vacuum power device 4 when the liquid level in the middle container 3 exceeds the first set liquid level. This control method not only prevents radioactive liquid from being sucked into the vacuum pipeline, but also can automatically optimize the system working condition according to the discharge rate of the continuous filtration device 1, realize adaptive operation, and reduce the radiation exposure risk brought by manual intervention.

[0043] Among them, the normal value of the liquid level of the middle container 3 of the first type of route receiving module is about 50% of the volume, not exceeding 80% of the volume. When exceeding this preset value (the first set liquid level), it is necessary to change the negative pressure provided by the vacuum power device 4 to avoid the filtrate being sucked into the vacuum power device 4. Generally, the filtrate of the second type of route receiving module does not enter the middle container 3 (that is, the first set liquid level is the 0 liquid level). When the first liquid level monitoring device 31 shows that there is a liquid level, it is necessary to change the negative pressure provided by the vacuum power device 4 to avoid the liquid being sucked into the vacuum power device 4.

[0044] In this embodiment, the filtrate receiving device 2 includes a filtrate receiving tank 21. There is liquid in the filtrate receiving tank 21. The port on the connecting pipe 5 connected to the filtrate receiving device 2 extends below the liquid level in the filtrate receiving tank 21 to form a liquid seal for the filtrate. That is, the radioactive filtrate sinks to the bottom of the tank naturally after entering through the pipe, and the sealing liquid always covers the filtrate to form a liquid seal barrier.

[0045] In this embodiment, the filtrate receiving system for continuous filtration of radioactive materials further includes a second control unit. The filtrate receiving device 2 further includes a second liquid level monitoring device 22 for monitoring the liquid level in the filtrate receiving tank 21. The filtrate receiving tank 21 is connected to an external filtrate treatment device 6. The second control unit is electrically connected to the second liquid level monitoring device 22 and the filtrate receiving tank 21 respectively. When the liquid level in the filtrate receiving tank 21 exceeds the second set liquid level, the filtrate receiving tank 21 transfers the filtrate to the filtrate treatment device 6. When the liquid level in the filtrate receiving tank 21 is lower than the third set liquid level, an alarm signal is generated. The second set liquid level is higher than the third set liquid level.

[0046] When the liquid level of the filtrate receiving tank 21 reaches the upper limit, the transfer is automatically started to send the filtrate downstream. When the liquid level of the filtrate receiving tank 21 reaches 70% - 80% of its volume, the filtrate is transferred to the filtrate treatment device 6, and the upper discharge method is required, such as vacuum-assisted empty lifting or siphon method. Because there may be solid particles in the filtrate receiving tank 21, the lower discharge method is avoided to prevent the solid particles from blocking the lower discharge pipe and device. An alarm is triggered at the lower limit to keep the filtrate receiving tank 21 above the lowest liquid level, which can ensure that the discharge pipe of the intermediate container 3 is always below the liquid level. The lowest liquid level of the filtrate receiving tank 21 is generally not lower than 100 mm. This design ensures that the filtrate receiving tank 21 always retains enough sealing liquid level to prevent the escape of radioactive gas, and at the same time avoids the air being sucked back into the system due to the emptying of the tank body, which may damage the vacuum environment, and realizes the safe turnover of the receiving device.

[0047] In this embodiment, the filtrate receiving tank 21 can adopt a special structure to ensure critical safety. When the filtrate flux to be processed is small, a conventional flat tank can be used; for general fluxes, an annular tank or a tube bundle tank can be used; for large volumes, a tube bundle tank can be used. For example, when the filtrate flux is 70 L, a flat tank with a width not exceeding 60 mm can be used; when it is 500 L, an annular tank with an annulus not exceeding 75 mm can be used; when it is 2 m 3 , a tube bundle tank filled with neutron poison can be used. The above tank structures are currently existing structures and will not be elaborated here.

[0048] In this embodiment, the filtrate receiving system for continuous filtration of radioactive materials further includes a third control unit and a dissolution solution adding device 7. The dissolution solution adding device 7 is connected to the filtrate receiving tank 21. The filtrate receiving device 2 further includes a component monitoring device 23 for monitoring the content of the components to be filtered in the filtrate receiving tank 21. The third control unit is electrically connected to the component monitoring device 23 and the dissolution solution adding device 7 respectively, and is used to control the dissolution solution adding device 7 to add the dissolution solution into the filtrate receiving tank 21 when the content of the components to be filtered in the filtrate receiving tank 21 exceeds the set content, so as to dissolve the components to be filtered. The component monitoring device 23 and the second liquid level monitoring device 22 can be integrated into the same fault identification device.

[0049] For example, when this system is used for filtrate receiving in the continuous filtration process of plutonium tail end, the component monitoring device 23 arranged in the filtrate receiving tank 21 is a plutonium mass monitoring device, and the corresponding dissolution solution adding device 7 is an ammonium carbonate adding device. The plutonium mass monitoring device is used to monitor whether there is plutonium scaling or a large amount of unfiltered plutonium oxalate appears in the filtrate receiving tank 21 due to the failure of the continuous filtration device 1. If plutonium scaling or unfiltered plutonium oxalate appears in the filtrate receiving tank 21, ammonium carbonate solution is added into the filtrate receiving tank 21 through the ammonium carbonate adding device to dissolve plutonium, and the mass concentration of ammonium carbonate is 3% - 20%.

[0050] In this embodiment, the vacuum power device 4 applies negative pressure to the intermediate container 3 by sucking gas, and the sucked gas is discharged to the vacuum power device 4. The vacuum power device 4 includes a trap 41, a scrubbing tank 42, an adjusting device 43 and a vacuum pump 44. The trap 41 is communicated with the cavity in the intermediate container 3, and the scrubbing tank 42, the adjusting device 43 and the vacuum pump 44 are sequentially connected downstream of the trap 41.

[0051] The trap 41 is used to trap the particles to be filtered in the gas. When the system is set in the plutonium tail-end process, the trap 41 collects the small particles of plutonium that may exist in the tail gas, avoiding contamination of downstream equipment. Different from ordinary traps, due to the processing of plutonium-containing gas, the trap 41 needs to ensure critical safety and adopt measures to monitor whether there is an uncontrolled accumulation of plutonium elements. Measures to ensure critical safety can include using a trap 41 with a small diameter, such as a diameter not exceeding 150 mm; or using a storage tank with a special structure, such as a tube bundle tank, an annular tank, or a flat tank, etc. Monitoring measures can use a neutron monitoring device. The scrubbing tank 42 is used to wash and remove the aerosol to be filtered and acid gas in the gas, that is, to wash the acid gas and the plutonium-containing aerosol, using dilute nitric acid with an acidity not lower than 0.5 mol / L. The regulating device 43 is used to regulate the negative pressure and suction flow rate of the vacuum pump 44. The vacuum pump 44 is used to provide negative pressure or vacuum pressure and discharge the suctioned gas to the external tail gas treatment device 8. Generally, it adopts a structure non-contact with the gas, and substances such as the oil of the vacuum pump 44 will not enter the gas in the system; if a water-sealed vacuum pump 44 is used, the water of the vacuum pump 44 needs to be additionally treated to prevent radioactive substances from overflowing through the water. The treated gas enters the tail gas treatment system for purification and then is discharged. It can be seen that except for the vacuum pump 44, the overall device does not require maintenance. Since the radioactive gas is intercepted and treated before the vacuum pump 44, the radioactivity of the vacuum pump 44 is extremely low and it can be directly maintained.

[0052] In this embodiment, the filtrate receiving system for continuous filtration of radioactive materials further includes a fourth control unit. Taking a group of intermediate containers 3, a vacuum power device 4, and a communication pipeline 5 connected between the continuous filtration device 1 and the filtrate receiving device 2 as a group of receiving modules, there are multiple groups of receiving modules, and each receiving module is connected in parallel between the continuous filtration device 1 and the filtrate receiving device 2. The fourth control unit is electrically connected to the continuous filtration device 1 and each receiving module respectively, and is used to control the conduction of the set receiving module according to the set requirements of the continuous filtration device 1.

[0053] Specifically, for continuous filtration, different vacuum pressures and suction flow rates may be required according to different filtration requirements. In this embodiment, each group of receiving modules is correspondingly set according to different requirements, and two types of receiving modules for two routes are set for each requirement. The fourth control unit selects the receiving module of the corresponding route to conduct according to the requirements and the filtrate situation. The above first, second, third, and fourth control units can be integrated and adopted as a total control unit.

[0054] Generally speaking, since the continuous filtration operation requires a vacuum (negative pressure) of no higher than -40 kPa and the pressure is stable, the vacuum cannot stop during continuous filtration. There is a possibility that a very small amount of particles penetrate the filter medium and enter the filtrate receiving device during continuous filtration, or the continuous filtration equipment fails to filter, and the precipitated crystals to be filtered enter the filtrate receiving device. Accordingly, this embodiment provides a filtrate receiving system for continuous filtration in a reprocessing plant, which meets the continuous filtration requirements at the plutonium tail end, provides continuous negative pressure for continuous filtration, and can export the filtrate at any time, meeting the process requirements of continuous filtration of plutonium oxalate at the plutonium tail end for negative pressure, continuous feeding and discharging, and maintenance-free. Avoid using underground valves, no need for inspection and maintenance, reduce the number of required equipment, simplify the operation process, reduce the floor area of the device, and have good economy. During the design process, critical safety is fully considered, and a fault identification device is set up to identify and handle possible process operation faults. This system can also be used for continuous filtration of radioactive materials in other processes except the plutonium tail end of the reprocessing plant, such as neptunium.

[0055] This system is arranged between the continuous filtration device 1 and the filtrate treatment device 6, and includes a filtrate receiving device 2, an intermediate container 3, a vacuum power device 4 (including a trap 41, a scrubbing tank 42, a regulating device 43, and a vacuum pump 44), and a connecting pipeline 5.

[0056] When using the first type of route receiving module: the feed pipeline 51 is connected to the top feed port of the intermediate container 3, and the discharge pipeline 52 extends to the bottom of the filtrate receiving tank 21. The filtrate and gas mixture in the continuous filtration device 1 enters the intermediate container 3 through the feed pipeline 51, the filtrate enters the filtrate receiving tank 21 through the discharge pipeline 52, and the gas in the intermediate container 3 is discharged to the vacuum power device 4.

[0057] When using the second type of route receiving module: the feed pipeline 51 is connected to the discharge pipeline 52, the feed pipeline 51 is connected to the feed port of the intermediate container 3 through an intake pipeline 53, and the discharge pipeline 52 extends to the bottom of the filtrate receiving tank 21. The gas in the feed pipeline 51 and the discharge pipeline 52 is pumped to the intermediate container 3 through the intake pipeline 53. The lower part of the intake pipeline 53 is liquid and the upper part is gas. The gas in the intermediate container 3 is discharged to the vacuum power device 4.

[0058] One or several sets of the first / second type of route receiving modules are selected according to the negative pressure and suction flow requirements of the continuous filtration device 1. When there are n groups of different negative pressures and suction flows of the continuous filtration device 1, n groups of the first / second type of route receiving modules need to be set. The second type of route receiving module is selected when the suction is for a continuous liquid or a very small amount of gas, and the first type of route receiving module is selected when the suction is for a gas and liquid mixture or a relatively large amount of gas.

[0059] The vacuum power device 4 includes a trap 41, a scrubbing tank 42, a regulating device 43, and a vacuum pump 44. The tail gas of the intermediate container 3 sequentially passes through the trap 41, the scrubbing tank 42, the regulating device 43, and the vacuum pump 44 and goes to the tail gas treatment device 8 for purification treatment of the tail gas. The filtrate receiving tank 21 is provided with a fault identification device, including a plutonium mass monitoring device and a second liquid level monitoring device 22. Ammonium carbonate is added to the filtrate receiving tank 21 by an ammonium carbonate adding device to dissolve the plutonium oxalate scale or unfiltered plutonium oxalate in the filtrate receiving tank 21. The filtrate receiving tank 21 transfers materials to the filtrate treatment device 6 in an upward discharging manner.

[0060] The present embodiment has the following beneficial effects:

[0061] (1) Provide a maintenance-free filtrate receiving system for continuous filtration in a reprocessing plant and an applicable process flow, meeting the process requirements such as negative pressure, continuous feeding and discharging, etc. for continuous filtration of plutonium oxalate at the tail end;

[0062] (2) Avoid using underground valves, which are maintenance-free, reduce the number of required devices, simplify the operation process, reduce the floor area of the device, and have good economy;

[0063] (3) Ensure the critical safety of operations involving plutonium-containing materials; can identify possible process operation failures and handle them.

[0064] Embodiment 2

[0065] The method for receiving filtrate for continuous filtration of radioactive materials in this embodiment uses the filtrate receiving system for continuous filtration of radioactive materials in Embodiment 1. The method includes the following steps:

[0066] Turn on the vacuum power device 4 to apply negative pressure to the cavity in the intermediate container 3;

[0067] The suction force formed by the negative pressure in the cavity of the intermediate container 3 sucks the filtrate generated by the continuous filtration device 1 into the connecting pipe 5 and then continuously transports it to the filtrate receiving device 2 through the connecting pipe 5.

[0068] Embodiment 3

[0069] The radioactive material continuous filtration facility of this embodiment includes a continuous filtration device 1, a filtrate treatment device 6, and the filtrate receiving system for continuous filtration of radioactive materials in Embodiment 1. The continuous filtration device 1 is used to filter radioactive materials and generate filtrate. The filtrate receiving system for continuous filtration of radioactive materials is connected between the continuous filtration device 1 and the filtrate treatment device 6, and is used to receive the filtrate generated by the continuous filtration device 1 and transfer the material to the filtrate treatment device 6. The filtrate treatment device 6 is used to treat the filtrate. The facility may further include an exhaust gas treatment device 8. The gas extracted by each vacuum power device 4 in the filtrate receiving system for continuous filtration of radioactive materials and the exhaust gas in the filtrate receiving tank 21 can be transported to the exhaust gas treatment device 8 for treatment.

[0070] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principle of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A filtrate receiving system for continuous filtration of radioactive materials, arranged at a continuous filtration device (1), characterized in that: It comprises a filtrate receiving device (2), an intermediate container (3), a vacuum power device (4) and a connecting pipe (5). The filtrate receiving device (2) is connected to the continuous filtering device (1) via a connecting pipe (5). The intermediate container (3) has a cavity inside, and the cavity is connected to the connecting pipe (5). The vacuum power device (4) is connected to the intermediate container (3) and applies negative pressure to the cavity in the intermediate container (3), so that the filtrate generated by the continuous filtering device (1) is sucked into the connecting pipe (5) by the suction force formed by the negative pressure, and then continuously transported to the filtrate receiving device (2) via the connecting pipe (5).

2. The filtrate receiving system for continuous filtration of radioactive materials according to claim 1, characterized in that: The filtrate receiving device (2) is located below the continuous filtering device (1) and the intermediate container (3). The filtrate sucked into the connecting pipe (5) is continuously transported to the filtrate receiving device (2) through the connecting pipe (5) under the action of gravity.

3. The filtrate receiving system for continuous filtration of radioactive materials according to claim 2, characterized in that: The connecting pipe (5) comprises a feed pipe (51) and a discharge pipe (52). The feed pipe (51) is connected to the top of the intermediate container (3) and the continuous filtering device (1). The discharge pipe (52) is connected to the bottom of the intermediate container (3) and the filtrate receiving device (2). The vacuum power device (4) applies negative pressure to the intermediate container (3), so that the gas-containing filtrate enters the cavity in the intermediate container (3) through the feed pipe (51), and completes the separation of gas and filtrate under the action of gravity, the upper gas is extracted by the vacuum power device (4), and the lower filtrate enters the filtrate receiving device (2) through the discharge pipe (52).

4. The filtrate receiving system for continuous filtration of radioactive materials according to claim 2, characterized in that: The connecting pipeline (5) comprises a feed pipeline (51), a discharge pipeline (52) and an air intake pipeline (53). The intermediate container (3) is located above the continuous filtering device (1). The discharge pipe (52) is connected to the bottom of the intermediate container (3) and the filtrate receiving device (2). The feed pipe (51) is connected to the top of the discharge pipe (52) and the continuous filtering device (1). The air inlet pipe (53) is a pipe branched from the feed pipe (51) and led upward and connected to the top of the intermediate container (3). The vacuum power device (4) applies negative pressure to the intermediate container (3), so that the negative pressure generated in the air inlet pipe (53) draws the filtrate into the discharge pipe (52) through the feed pipe (51), and then into the filtrate receiving device (2) through the discharge pipe (52).

5. The filtrate receiving system for continuous filtration of radioactive materials according to claim 3 or 4, characterized in that: The inner diameter of the discharge pipe (52) is greater than the inner diameter of the feed pipe (51).

6. The filtrate receiving system for continuous filtration of radioactive materials according to claim 2, characterized in that: The height difference between the filtrate receiving device (2) and the continuous filtering device (1) in the vertical direction is not less than 6 m.

7. The filtrate receiving system for continuous filtration of radioactive materials according to claim 1, characterized in that: Also includes a first control unit, The intermediate container (3) is provided with a first liquid level monitoring device (31) for monitoring the liquid level in the intermediate container (3). The first control unit is electrically connected to the first liquid level monitoring device (31) and the vacuum power device (4) respectively, and is used to adjust the negative pressure provided by the vacuum power device (4) when the liquid level in the intermediate container (3) exceeds a first set liquid level.

8. The filtrate receiving system for continuous filtration of radioactive materials according to claim 1, characterized in that: The filtrate receiving device (2) comprises a filtrate receiving tank (21), wherein the filtrate receiving tank (21) contains liquid. The port on the communication pipe (5) connected to the filtrate receiving device (2) extends below the liquid level in the filtrate receiving tank (21) to form a liquid seal for the filtrate.

9. The filtrate receiving system for continuous filtration of radioactive materials according to claim 8, characterized in that: Also includes a second control unit, The filtrate receiving device (2) further comprises a second liquid level monitoring device (22) for monitoring the liquid level in the filtrate receiving tank (21). The filtrate receiving tank (21) is connected to an external filtrate processing device (6). The second control unit is electrically connected to the second liquid level monitoring device (22) and the filtrate receiving tank (21) respectively, and is used to transfer the filtrate receiving tank (21) to the filtrate processing device (6) when the liquid level in the filtrate receiving tank (21) exceeds a second set liquid level, and to generate an alarm signal when the liquid level in the filtrate receiving tank (21) is lower than a third set liquid level, and the second set liquid level is higher than the third set liquid level.

10. The filtrate receiving system for continuous filtration of radioactive materials according to claim 8, characterized in that: It also includes a third control unit and a dissolving liquid adding device (7), The dissolving liquid adding device (7) is connected to the filtrate receiving tank (21), The filtrate receiving device (2) further comprises a component monitoring device (23) for monitoring the content of the component to be filtered in the filtrate receiving tank (21). The third control unit is electrically connected to the component monitoring device (23) and the dissolving liquid adding device (7) respectively, and is used to control the dissolving liquid adding device (7) to add dissolving liquid into the filtrate receiving tank (21) to dissolve the component to be filtered when the content of the component to be filtered in the filtrate receiving tank (21) exceeds a set content.

11. The filtrate receiving system for continuous filtration of radioactive materials according to claim 1, characterized in that: The vacuum power device (4) applies negative pressure to the intermediate container (3) by sucking gas, and the vacuum power device (4) comprises a collector (41), a gas washing tank (42), a regulating device (43) and a vacuum pump (44). The collector (41) is connected to the cavity in the intermediate container (3), and the gas washing tank (42), the regulating device (43) and the vacuum pump (44) are connected downstream of the collector (41) in sequence. The collector (41) is used to capture particles to be filtered in the gas. The gas washing tank (42) is used to wash and remove the aerosol to be filtered and the acid gas in the gas. The regulating device (43) is used to regulate the pressure and flow of the vacuum pump (44). The vacuum pump (44) is used to provide negative pressure and discharge the sucked gas to an external tail gas treatment device (8).

12. The filtrate receiving system for continuous filtration of radioactive materials according to any one of claims 1 to 4 and 6 to 11, characterized in that: Also includes a fourth control unit, A group of intermediate containers (3), a vacuum power device (4) and a connecting pipe (5) connected between a continuous filtering device (1) and a filtrate receiving device (2) are used as a group of receiving modules. The receiving modules are provided in multiple groups, and each receiving module is connected in parallel between the continuous filtering device (1) and the filtrate receiving device (2). The fourth control unit is electrically connected to the continuous filtering device (1) and each receiving module respectively, and is used to control the setting of the receiving module to be turned on according to the setting requirements of the continuous filtering device (1).

13. A method for receiving filtrate for continuous filtration of radioactive materials, characterized in that: Using the filtrate receiving system for continuous filtration of radioactive materials according to any one of claims 1 to 12, the method comprises the following steps: Turning on the vacuum power device (4) to apply negative pressure to the cavity in the intermediate container (3); The suction force formed by the negative pressure in the cavity of the intermediate container (3) sucks the filtrate generated by the continuous filtering device (1) into the connecting pipe (5), and then continuously transports the filtrate to the filtrate receiving device (2) through the connecting pipe (5).

14. A radioactive material continuous filtration facility, characterized in that: It comprises a continuous filtering device (1), a filtrate treatment device (6) and a filtrate receiving system for continuous filtration of radioactive materials according to any one of claims 1 to 12, The continuous filtering device (1) is used to filter radioactive materials and produce filtrate; The filtrate receiving system for continuous filtration of radioactive materials is connected between the continuous filtration device (1) and the filtrate processing device (6), and is used to receive the filtrate generated by the continuous filtration device (1) and transfer the filtrate to the filtrate processing device (6); The filtrate treatment device (6) is used to treat the filtrate.

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