CN114887445A - Polonium removal system and method for lead bismuth cooled reactor - Google Patents

Abstract

Embodiments of the present invention disclose a polonium removal system and method for a lead-bismuth cooled reactor. Wherein, the polonium removal system is connected with the reactor vessel of the lead-bismuth cooling reactor, and is used for removing the polonium aerosol in the covering gas in the reactor vessel. The polonium removal system includes: an adsorption device, an adsorption module is installed in the adsorption device, and the adsorption module is used for adsorbing polonium in the covering gas; a gas circulation pipeline is arranged between the adsorption device and the reactor Between the containers, a circulation pump is arranged on the gas circulation pipeline, and the circulation pump is used to transport the cover gas in the reactor container to the adsorption device and transport the adsorbed and purified cover gas back to the reactor container ; A polonium monitoring device, arranged on the gas circulation pipeline, is used to monitor the polonium content in the covering gas.

Description

Polonium removal system and method for lead-bismuth cooled reactors

technical field

Embodiments of the present invention relate to the technical field of radioactive material processing, in particular to a system and method for removing polonium for a lead-bismuth cooling reactor.

Background technique

Liquid lead-bismuth alloy is a good coolant for bulk neutron reactors. When the liquid lead-bismuth alloy is used as the coolant of the fast neutron reactor, the lead-bismuth alloy will produce radioactive polonium after being irradiated by neutrons, which is highly dangerous. Moreover, because polonium has strong volatility, under high temperature conditions, polonium will volatilize from the liquid lead-bismuth alloy coolant into the cover gas above the coolant, so that there is a certain amount of radioactive polonium in the cover gas.

Therefore, in order for a lead-bismuth-cooled reactor to operate safely, and to prevent leakage or release of the radioactive polonium-containing capping gas into the atmosphere, the polonium in the capping gas needs to be removed.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a polonium removal system for a lead-bismuth cooled reactor is provided. The polonium removal system is connected to the reactor vessel of the lead-bismuth cooling reactor, and is used for removing the polonium aerosol in the covering gas in the reactor vessel. The polonium removal system includes: an adsorption device, an adsorption module is installed in the adsorption device, and the adsorption module is used for adsorbing polonium in the cover gas; a gas circulation pipeline is arranged between the adsorption device and the reactor Between the containers, a circulation pump is arranged on the gas circulation pipeline, and the circulation pump is used to transport the cover gas in the reactor container to the adsorption device and transport the adsorbed and purified cover gas back to the reactor container ; A polonium monitoring device, arranged on the gas circulation pipeline, is used to monitor the polonium content in the covering gas.

According to another aspect of the present invention, a method of removing polonium for a lead-bismuth cooled reactor is provided. The method for removing polonium includes: starting a circulating pump on a gas circulation pipeline in a polonium removal system, and transporting the cover gas in the reactor vessel to an adsorption device, so that the polonium aerosol in the cover gas is adsorbed on the adsorption device The adsorption module inside the reactor; the cover gas after adsorption and purification is transported back to the reactor container; the cover gas in the reactor container is adsorbed cyclically until the polonium content in the cover gas reaches a predetermined standard, and the gas circulation pipeline is stopped. gas circulation.

Description of drawings

Other objects and advantages of the present invention will be apparent from the following description of embodiments of the present invention with reference to the accompanying drawings, and may assist in a comprehensive understanding of the present invention.

FIG. 1 is a schematic structural diagram of a polonium removal system according to an embodiment of the present invention.

2 is a schematic structural diagram of an adsorption device in a polonium removal system according to an embodiment of the present invention.

3 is a schematic flowchart of a method for removing polonium according to an embodiment of the present invention.

It should be noted that the accompanying drawings are not necessarily drawn to scale, but are only shown in a schematic manner that does not affect the reader's understanding.

Description of reference numbers:

10, adsorption device; 20, isolation valve; 30, circulating pump; 40, vacuum device; 50, inert gas device; 60, polonium monitoring device; 70, heat tracing and insulation device; 81, flow measuring device; 82, pressure measuring device ; 83, temperature measurement device; 90, sealed transport device; 200, reactor vessel.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiment is one embodiment of the present application, but not all embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present application shall have the usual meanings understood by those with ordinary skills in the field to which the present application belongs. If descriptions such as "first" and "second" are involved in the whole text, the descriptions such as "first" and "second" are only used to distinguish similar objects, and should not be construed as indicating or implying their relative importance, sequence, etc. The order or the quantity of the indicated technical features is implicitly indicated, and it should be understood that the data described by "first", "second", etc. can be interchanged under appropriate circumstances. If "and/or" appears in the whole text, it means that it includes three parallel schemes. Taking "A and/or B" as an example, it includes scheme A, scheme B, or scheme that A and B satisfy at the same time. Furthermore, for ease of description, spatially relative terms, such as "above," "below," "top," "bottom," etc., may be used herein to describe only one device or feature as shown in the figure versus other devices or features. The spatial relationship of features should be understood to also encompass different orientations in use or operation in addition to the orientation shown in the figures.

FIG. 1 shows a schematic structural diagram of a polonium removal system according to an embodiment of the present invention. The polonium removal system in this embodiment is used in a lead-bismuth reactor, and the polonium removal system is connected to the reactor vessel of the lead-bismuth reactor, and is used for removing the polonium aerosol in the covering gas in the reactor vessel. Wherein, the inert gas is the gas used to protect the coolant and/or the coolant pipeline in the reactor vessel, and generally, the inert gas is used as the covering gas, for example, argon gas.

As shown in FIG. 1 , the polonium removal system in this embodiment includes an adsorption device 10 , a gas circulation pipeline and a polonium monitoring device 60 . Wherein, an adsorption module 13 is installed in the adsorption device 10, and the adsorption module 13 is used for adsorbing polonium (Po-210) in the covering gas. The gas circulation pipeline is arranged between the adsorption device 10 and the reactor vessel 200 , and a circulation pump 30 is arranged on the gas circulation pipeline, and the circulation pump 30 is used to cover the inside of the reactor vessel 200 . The gas is delivered to the adsorption device 10 and the adsorption-purified cover gas is delivered back to the reactor vessel 200 , so that the cover gas in the reactor vessel is circulated in the gas circulation line. The polonium monitoring device 60 is disposed on the gas circulation pipeline, and is used for monitoring the polonium content in the covering gas, so as to judge whether the covering gas in the reactor vessel meets the purification requirements.

Using the polonium removal system in this embodiment, the polonium aerosol generated during the operation of the lead-bismuth reactor can be removed, and the polonium in the covering gas in the reactor vessel can be removed by adsorbing the polonium aerosol. In addition, the radioactive cover gas adopts a loop structure design between the polonium removal system and the reactor vessel, so that the radioactive gas forms a closed cycle, reduces the risk of radioactive gas leakage, and can continuously, efficiently and safely remove the polonium in the cover gas. adsorption removal.

In this embodiment, the circulating pump 30 on the gas circulating pipeline can be used to adjust the gas flow in the gas circulating pipeline. The operator can adjust the gas flow in real time through the circulating pump according to the operating state of the polonium removal system. Optionally, the circulating pump in this embodiment can adjust the gas flow rate within the range of 0 to 5.0 m ³ /h. In addition, the leakage rate of the gas circulation pipeline in this embodiment is extremely small, not exceeding 1×10 ^-7 Pa·m/s.

In addition, the gas circulation pipeline in this embodiment is also provided with a measuring device for measuring gas parameters of the gas in the gas circulation pipeline, wherein the gas parameters of the gas include at least one of the flow rate, pressure, and temperature of the gas . The measuring device includes at least one of a flow measuring device 81 , a pressure measuring device 82 and a temperature measuring device 83 .

In some embodiments, the polonium removal system may be coupled to a lead-bismuth cooled reactor. An isolation valve 20 is provided between the polonium removal system and the reactor vessel, and the isolation valve 20 can be selectively opened or closed. When the isolation valve is opened, gas can be communicated between the reactor vessel and the polonium removal system; when the isolation valve is closed, the gas between the reactor vessel and the polonium removal system There is no flow through to isolate the polonium removal system from the reactor vessel.

FIG. 2 shows a schematic structural diagram of an adsorption device according to an embodiment of the present invention. As shown in FIG. 2 , a plurality of adsorption modules 13 arranged at intervals are installed in the adsorption device 10 in this embodiment. The plurality of adsorption modules 13 are arranged in parallel, and there is a predetermined interval between two adjacent adsorption modules. The cover gas in the reactor vessel 200 enters from the inlet 11 of the adsorption device 10 through the gas circulation pipeline, and the cover gas flows into the flow channel in the adsorption device 10 along the interval between the adsorption modules in the adsorption device 10 .

The adsorption device 10 in this embodiment is provided with a flow distributor and a plurality of flow channels, wherein the flow channels are used for the flow of the cover gas, and the flow distributor is used for all the air entering the adsorption device 10. The cover gas is distributed to each flow channel. The flow distributor is disposed close to the inlet of the adsorption device 10, and the cover gas introduced from the inlet is distributed to the plurality of flow channels through the flow distributor, and a plurality of the flow channels can pass through a plurality of adsorption modules 13, so that the cover gas flows through the plurality of adsorption modules 13 through each flow channel, and then flows out from the outlet 12 of the adsorption device 10 into the gas circulation pipeline. As shown in FIG. 2 , the cover gas flows along the flow direction A in the adsorption device 10 , wherein the inlet of the flow channel may be arranged in the interval between the adsorption modules 13 . The adsorption module 13 in this embodiment can maximally adsorb and fix the polonium aerosol in the cover gas, so as to realize the adsorption and purification of the cover gas.

Optionally, a serpentine flow channel is provided between the plurality of adsorption modules 13 in the adsorption device 10, and the covering gas flows in the serpentine flow channel and passes through each of the adsorption modules 13 multiple times, so that all the The polonium aerosol in the cover gas is adsorbed and fixed on the plurality of adsorption modules 13 to realize the purification of the cover gas.

In this embodiment, the adsorption module 13 includes a metal mesh and a non-metallic film wrapped around the metal mesh. Wherein, the non-metallic film may be made of polymer materials such as cellulose and resin, or may be made of oxide materials such as silica and manganese dioxide, and composite materials based on the oxide materials. The metal mesh can be a wire mesh made of gold, silver, platinum, stainless steel and other materials. Optionally, the non-metallic membrane or metal mesh can be arranged in a single layer or in a multi-layer overlapping arrangement, so as to perform physical adsorption and filtration on the covering gas mixed with polonium aerosol.

In some embodiments, the adsorption module 13 is further provided with a chemical adsorption unit, and the chemical adsorption unit may be provided between two metal meshes, two non-metallic films, or between a metal mesh and a non-metallic film. For example, the adsorption module 13 is sequentially provided with a non-metallic film, a metal mesh, a chemical adsorption unit, a metal mesh and a non-metallic film from one side to the other side. The chemical adsorption unit utilizes chemical reactions to convert Po-210 and its compounds into other stable compounds containing Po-210, thereby completing the removal of Po-210.

With the adsorption device 10 in this embodiment, the polonium in the cover gas can be adsorbed mainly by physical adsorption and supplemented by chemical adsorption, so as to purify the cover gas.

As shown in FIG. 1 , the polonium monitoring device 60 in this embodiment is disposed on the gas circulation pipeline before the inlet of the adsorption device 10 , and/or on the gas circulation pipeline after the outlet of the adsorption device 10 . The polonium monitoring device 60 in this embodiment can monitor the polonium content of the gas in the gas circulation pipeline, so as to provide a judgment basis for the adsorption efficiency and purification effect of the polonium removal system.

Optionally, the detection method of the polonium monitoring device 60 is to perform detection after the sample is enriched online.

Wherein, the polonium monitoring device 60 disposed before the inlet of the adsorption device 10 can monitor the polonium content in the covering gas delivered from the reactor vessel, thereby judging whether the covering gas in the reactor vessel meets the purification requirements. After the covering gas in the reactor vessel meets the purification requirements, the gas flow rate can be adjusted by the circulating pump 30 on the gas circulation line, so that the gas flow rate in the gas circulation line is gradually reduced until the gas flow rate is zero. Purification of cover gases.

Meanwhile, the polonium monitoring device 60 disposed after the outlet of the adsorption device 10 can monitor the polonium content of the cover gas adsorbed and purified by the adsorption device 10 . According to the monitoring results of the two polonium monitoring devices 60 before and after the adsorption device 10 , the adsorption efficiency of the adsorption device 10 can be judged.

The working gas environment of the adsorption device 10 in this embodiment is cover gas and radioactive polonium aerosol. In order to maintain the working gas environment of the adsorption device 10 , the polonium removal system further includes a vacuum device 40 and an inert gas device 50 .

As shown in FIG. 1 , the vacuum device 40 is connected to the adsorption device for adjusting the pressure of the gas in the adsorption device to maintain the working gas environment required by the adsorption device and maintain the polonium removal system at the same time Equilibrate with the gas in the reactor vessel.

The polonium removal system further includes an inert gas device 50, which is connected to the adsorption device 10 and used to provide the adsorption device 10 with the same inert gas as the covering gas in the reactor vessel 200, which is an adsorption device The required working gas environment is provided so as to maintain the working gas environment required by the adsorption device, while maintaining the gas balance between the polonium removal system and the reactor vessel.

Additionally, the adsorption device 10 may operate at higher temperatures. The adsorption device 10 in this embodiment can be used to adsorb the cover gas in the lead-bismuth cooling reactor. The working temperature of the adsorption device is between 200 and 400°C, and the working pressure is -0.1 MPa to 0.5 MPa.

As shown in FIG. 1 , the polonium removal system in this embodiment further includes a closed transport device 70 . The closed transfer device 70 is used to disassemble, replace and seal transfer the adsorption module 13 in the adsorption device 10 .

After completing the adsorption and purification of the cover gas in the reactor vessel and isolating the polonium removal system from the reactor vessel, the adsorption module in which the polonium is adsorbed and fixed in the adsorption device can be disassembled through the closed transfer device 70, and the adsorption module in the adsorption device can be automatically packaged and transported in a sealed manner to Proper disposal in designated area. In addition, after the used adsorption module 13 adsorbing and immobilizing polonium is disassembled, a new adsorption module 13 can also be installed through the airtight transfer device 70 for the next gas purification. The leak rate of the airtight transfer device 70 in this embodiment is relatively small, not exceeding 1×10 ^-8 Pa·m/s, which reduces the risk of radioactive leakage.

As shown in FIG. 1 , the polonium removal system also includes a heat tracing and insulation device 90 . The heat tracing and heat preservation device 90 is arranged on the gas circulation pipeline near the inlet of the reactor vessel 200 , and is used for heating and insulating the purified cover gas, so that the purified cover gas is heated to the inside of the reactor vessel 200 . The covering gas is kept at the same temperature level and kept warm, and then enters the reactor vessel to avoid thermal disturbance due to excessive temperature difference and destroy the thermal balance in the reactor vessel.

Optionally, the heat tracing and heat preservation device 90 may be a heating belt wrapped on the gas circulation pipeline, and may heat the gas in the gas circulation pipeline. Optionally, a temperature measuring device 83 is provided on the gas circulation pipeline near the inlet and the outlet of the reactor vessel. The temperature measuring device 83 at the outlet can measure the temperature of the covering gas in the reactor vessel 200 to provide reference data for the heating of the covering gas by the heat tracing and insulation device 90, so that the purified gas can be heated to a temperature similar to that in the reactor vessel 200. The gas temperature is the same. The temperature measuring device 83 at the inlet can measure the temperature of the purified cover gas to determine whether it needs to be heated.

In addition, the polonium removal system also includes a control device (not shown in the figure), the control device and at least one of the circulating pump 30 , the vacuum device 40 , the inert gas device 50 and the heat tracing and insulation device 90 on the gas circulating pipeline A connection for controlling gas parameters in the gas circulation line.

Optionally, when the adsorption efficiency of the adsorption device 10 does not reach the standard, the gas parameters in the polonium removal system can be adjusted in combination with the gas flow, pressure, temperature and other parameters monitored by the measuring device in the gas circulation pipeline, so that the adsorption of the adsorption device can be improved. Efficiency is up to standard.

The polonium removal system in the embodiment of the present invention has the characteristics of safe and stable operation and high adsorption efficiency, and can realize on-line enrichment and detection functions and removal functions of polonium in a lead-bismuth cooling reactor. Using the polonium removal system in the embodiment of the present invention mainly uses physical adsorption and supplements chemical adsorption, and can safely and efficiently remove polonium in the cover gas in the lead-bismuth cooling reactor. In addition, the polonium removal system adopts a loop structure design, so that the radioactive covering gas and the polonium aerosol mixed in it form a closed cycle, which reduces the risk of radioactive gas leakage.

Embodiments of the present invention also provide a method for removing polonium for a lead-bismuth-cooled reactor. The method for removing polonium in the embodiments of the present invention can be implemented by using the system for removing polonium in the above-mentioned embodiments. In addition, the polonium removal process in this embodiment can be performed while the reactor is out of operation.

FIG. 3 shows a flow chart of a method for removing polonium according to one embodiment of the present invention. As shown in FIG. 3 , the method for removing polonium in this embodiment includes the following steps.

Step S10, start the circulation pump on the gas circulation pipeline in the polonium removal system.

Step S20, controlling the covering gas in the reactor vessel to circulate in the polonium removal system, wherein the circulating pump transports the covering gas in the reactor vessel to the adsorption device, so that the polonium aerosol in the covering gas is adsorbed on the polonium aerosol. The adsorption module in the adsorption device; the cover gas after adsorption and purification is transported back to the reactor vessel.

Step S30, monitoring the content of polonium in the covering gas in real time.

Step S40, when the content of polonium in the covering gas reaches a predetermined standard, stop the gas circulation in the gas circulation pipeline.

Specifically, in step S10, before starting the circulating pump, it is also necessary to detect the operating state of the polonium removal system to ensure that the equipment, devices and instruments in the system work stably, and have the ability to purify the gas covered by the reactor vessel to remove polonium. .

In addition, before starting, the isolation valve between the reactor and the polonium removal system also needs to be opened to release the isolation of the polonium removal system from the reactor, and then start the polonium removal system.

In this embodiment, after starting the circulation pump on the gas circulation line between the reactor vessel and the polonium removal system, the circulation pump can be controlled so that the gas flow in the gas circulation line is controlled at a lower predetermined flow level, To establish a gas circulation loop in the polonium removal system. Wherein, the predetermined flow level can be set to 0.5m ³ /h.

Further, after the polonium removal system operates stably, the circulating gas flow rate in the gas circulating pipeline can be gradually increased.

In step S20, when the cover gas circulates in the polonium removal system, the adsorption device in the adsorption device can adsorb the polonium aerosol in the cover gas through the adsorption device, thereby purifying the cover gas. The purified cover gas is transported back to the reactor vessel through the gas circulation pipeline, so that the cover gas in the reactor vessel is subjected to circulating adsorption.

When the polonium content in the covering gas reaches a predetermined standard, the gas circulation in the gas circulation pipeline can be stopped, so as to complete the purification of the covering gas in the reactor vessel.

In some embodiments, the polonium content of the gas entering and/or leaving the adsorption device can be monitored in real time as the blanket gas in the reactor vessel circulates in the polonium removal system to determine whether the polonium content of the blanket gas in the reactor vessel is meet the predetermined standard.

Optionally, the adsorption efficiency of the adsorption device can also be determined in real time according to the polonium content of the gas entering and leaving the adsorption device. In some embodiments, the adsorption efficiency can be judged by the first reading of the polonium monitoring device after the outlet of the adsorption device, and the second reading of the polonium monitoring device before the inlet of the adsorption device. For example, when the first indication is less than 5% of the second indication, it can be determined that the adsorption efficiency of the adsorption device is above 95%.

In order to maximize the utilization of the adsorption device, the adsorption efficiency of the adsorption device can be controlled above a predetermined efficiency. For example, the adsorption efficiency of the adsorption device is set to 95%. In this embodiment, the adsorption efficiency of the adsorption device can be adjusted by adjusting the gas parameters in the gas circulation pipeline. Wherein, the gas parameter includes at least one of gas flow, pressure, and temperature.

Specifically, the adsorption efficiency can be adjusted by adjusting the gas flow in the gas circulation pipeline. When the adsorption efficiency of the adsorption device is greater than the predetermined efficiency, the flow rate of the circulating gas in the system can be appropriately increased by controlling the circulating pump, so as to maximize the utilization of the adsorption module in the adsorption device, and quickly realize the coverage of the reactor vessel through the adsorption module. Gas purification. When the adsorption efficiency of the adsorption device is less than the predetermined efficiency, the flow rate of the circulating gas in the system can be reduced by controlling the circulating pump, so that the adsorption efficiency of the adsorption device is above 95%, thereby realizing the efficient removal of polonium.

In this embodiment, the polonium removal system operates in a gaseous environment covering the gas and the polonium aerosol. By controlling the vacuum device and/or the inert gas device, the gas environment in the adsorption device can be maintained, and the polonium removal system can also be maintained in equilibrium with the gas in the reactor vessel.

In addition, when the cover gas is circulated in the polonium removal system, the gas circulation pipeline near the reactor vessel inlet can be heat traced and insulated to heat the adsorbed and purified cover gas to the same temperature as the cover gas in the reactor vessel. , and then transported back to the reactor vessel to avoid thermal disturbance due to excessive temperature difference and destroy the thermal balance in the reactor vessel.

In step S30, during the gas circulation process, the polonium content of the covering gas in the reactor vessel is monitored in real time by the polonium monitoring device before the adsorption device.

When the polonium content in the covering gas in the reactor vessel reaches a predetermined standard, the gas flow rate in the gas circulation pipeline can be slowly reduced to 0 m ³ /h to stop the operation of the polonium removal system. Wherein, the predetermined standard can be set according to actual needs, and if the polonium content is below the predetermined standard, it can be considered that the purification of the cover gas is completed.

After the polonium removal system stops running, the isolation valve between the reactor vessel and the polonium removal system is closed to isolate the polonium removal system from the reactor vessel, and the adsorption and purification of the covering gas in the reactor vessel is ended.

After the adsorption and purification is completed, the adsorption module in the adsorption device is disassembled, sealed and transferred, and a new adsorption module is installed in the adsorption device. Specifically, the adsorption module in the adsorption device can be packaged and sealed by a closed transport device, and then transferred to a designated area for proper disposal. At the same time, a new adsorption module is installed for the adsorption device through a closed transfer system to facilitate the next gas purification.

Finally, after replacing the adsorption module in the adsorption device, control the reactor to resume operation.

By using the method for removing polonium in this embodiment, the polonium in the cover gas in the lead-bismuth cooling reactor can be safely, efficiently and continuously removed, and the risk of radioactive gas leakage is reduced.

For the embodiments of the present invention, it should also be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other to obtain new embodiments.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (20)

1. A polonium removal system for lead bismuth cooled reactor is characterized in that,

the polonium removal system is connected to the reactor vessel of the lead-bismuth cooled reactor for removing polonium aerosol in a cover gas in the reactor vessel;

the polonium removal system comprises:

an adsorption device, in which an adsorption module is installed, for adsorbing polonium in the cover gas;

the gas circulation pipeline is arranged between the adsorption device and the reactor vessel, and is provided with a circulating pump which is used for conveying the cover gas in the reactor vessel to the adsorption device and conveying the cover gas subjected to adsorption and purification back to the reactor vessel;

A polonium monitoring device disposed on the gas circulation line for monitoring polonium content in the blanket gas.

2. The polonium removal system of claim 1, wherein an isolation valve is disposed between the polonium removal system and the reactor vessel, the isolation valve being selectively openable or closable for controlling gas communication between the polonium removal system and the reactor vessel.

3. The polonium removal system of claim 1, wherein a plurality of adsorption modules are installed at intervals in the adsorption apparatus.

4. The polonium removal system of claim 3, wherein the adsorption module has a flow distributor and a plurality of flow channels disposed therein;

wherein the flow distributor is configured to distribute the cover gas entering the adsorption device to the plurality of flow channels;

the flow channel is used for flowing the covering gas and is connected with a plurality of adsorption modules.

5. A polonium removal system of any of claims 1-4 wherein the adsorption module comprises: the metal net and the non-metal film wrapped outside the metal net.

6. The polonium removal system of claim 1, wherein the polonium monitoring device is disposed on a gas circulation line before the inlet of the adsorption device and/or on a gas circulation line after the outlet of the adsorption device.

7. The polonium removal system of claim 1, further comprising: the vacuum device is connected with the adsorption device and is used for adjusting the pressure of the gas in the adsorption device.

8. A polonium removal system according to claim 1 or 7, further comprising: and the inert gas device is connected with the adsorption device and used for providing the adsorption device with the inert gas which is the same as the covering gas in the reactor container.

9. The polonium removal system of claim 1, further comprising: and the closed transfer device is used for disassembling, replacing and hermetically transferring the adsorption module in the adsorption device.

10. The polonium removal system of claim 1, further comprising: and the heat tracing and heat insulating device is arranged on the gas circulation pipeline close to the inlet of the reactor vessel and is used for heating and insulating the purified cover gas.

11. The polonium removal system of claim 1, further comprising: and the gas measuring device is arranged on the gas circulating pipeline and used for measuring the gas parameters of the gas in the gas circulating pipeline.

12. A polonium removal system according to any one of claims 1-11 comprising:

And the control device is connected with at least one of the circulating pump, the vacuum device, the inert gas device and the heat tracing and heat insulating device on the gas circulating pipeline and is used for controlling gas parameters in the gas circulating pipeline.

13. A polonium removal method for a lead-bismuth cooled reactor, comprising:

starting a circulating pump on a gas circulating pipeline in the polonium removal system,

controlling a cover gas in a reactor vessel to circulate in a polonium removal system, wherein the circulation pump delivers the cover gas within the reactor vessel to an adsorption device to cause polonium aerosol in the cover gas to be adsorbed by an adsorption module within the adsorption device; conveying the cover gas subjected to adsorption purification back to the reactor container;

the polonium content of the blanket gas was monitored in real time,

when the polonium level in the blanket gas reaches a predetermined level, the gas circulation in the gas circulation line is stopped.

14. The method of claim 13 wherein a vacuum device and/or an inert gas device is controlled to maintain a gas environment in the adsorption device and/or a polonium removal system in equilibrium with the gases within the reactor vessel.

15. The method of claim 13 wherein the polonium content of the gas entering and/or exiting the adsorption unit is monitored to determine whether the polonium content of the blanket gas in the reactor vessel meets a predetermined criterion.

16. The method of claim 15 wherein the adsorption efficiency of the adsorption unit is determined according to the polonium content of the gas entering and exiting the adsorption unit.

17. The method of claim 16, wherein a gas parameter in the gas circulation line is adjusted to adjust the adsorption efficiency of the adsorption device.

18. The method of claim 17, wherein the gas parameters comprise: at least one of flow rate, pressure, temperature of the gas.

19. The method of claim 13, wherein the gas circulation line near the reactor vessel inlet is heat traced to heat the blanket gas after adsorptive cleaning to the same temperature as the blanket gas in the reactor vessel and then returned to the reactor vessel.

20. The method of claim 13, further comprising:

after adsorption purification is finished, the adsorption modules in the adsorption device are disassembled and sealed to be transferred, and new adsorption modules are installed in the adsorption device.

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