Colloid-mediated nuclide migration behavior simulation and monitoring system

Abstract

The invention provides a colloid-mediated nuclide migration behavior simulation and monitoring system, which is characterized in that a solution regulation and control unit and a dynamic light scattering in-situ analysis unit are improved; the technical bottlenecks of nuclide migration behavior research such as migration environment condition instability and difficulty in in-situ distinguishing of colloid carrier band contribution caused by dynamic fluctuation of chemical properties of the migration solution are broken through. The pH / conductivity sensor group is arranged at the inflow end of the soil column body to monitor chemical parameters of a solution in real time, and when it is detected that the carbonate concentration and the pH value deviate from set threshold values, dynamic adjustment of migration environment parameters in the nuclide migration simulation process is achieved through quantitative automatic compensation. The dynamic light scattering analysis assembly is directly coupled to an outlet of a soil cylinder through a low-adsorption flow path, the contribution proportion of organic fake colloids such as inorganic colloids and humus to nuclide migration can be distinguished in situ in combination with synchronously collected nuclide activity data, and dynamic hydrochemical condition simulation and in-situ colloid-nuclide collaborative analysis are achieved.

Description

Technical Field

[0001] This invention belongs to the field of radionuclide processing technology, and particularly relates to a colloidal-mediated nuclide migration behavior simulation and monitoring system. Background Technology

[0002] Soil column migration experiments are currently the main method for studying the migration behavior of radionuclides (especially actinide elements such as plutonium) in claystone. Existing soil column migration experiments rely on manual, timed sampling (e.g., every 24-72 hours) to collect effluent from the soil column, obtaining key chemical parameters such as carbonate concentration through offline laboratory analysis (e.g., titration, ion chromatography). Based on the analytical results, the carbonate composition of the injected fluid is then manually adjusted (e.g., by adding NaHCO3 solution). This results in a response lag of several hours to several days, making it impossible to track the dynamic chemical equilibrium of groundwater in real time. The lag in carbonate concentration adjustment also leads to the experimental system remaining in a non-equilibrium state for extended periods (e.g., pH fluctuations of ±0.5 units), triggering valence state transformations of radionuclides (e.g., Pu(IV) / Pu(V)). Experiments have shown that a 10% change in carbonate concentration can lead to a speciation rate >15%, thus causing a decrease in the retardation factor R. d Parameters deviate from their true values.

[0003] Current soil column migration experiments employ offline separation techniques to monitor colloid-nuclein interactions. This method requires interrupting the experiment to centrifuge or filter the effluent in stages, separating true colloids (e.g., Pu(OH)4) from humic pseudocolloids. Then, it involves two steps: first, measuring the activity of dissolved nuclides in the filtrate (e.g., gamma spectroscopy), and then estimating the colloid carrier fraction through the difference. Therefore, it cannot simultaneously obtain real-time correlation data between colloidal particle size distribution and nuclide activity. Offline operation not only disrupts colloidal stability (e.g., centrifugation leads to humic aggregates) but also fails to distinguish the dynamic contributions of true and pseudocolloids during migration. Studies have shown that humic pseudocolloids can increase plutonium migration rates by 100 times, but current offline separation techniques cannot quantify their weight. Furthermore, human intervention causes multiple interruptions to the migration process, making it difficult to obtain continuous migration curves, potentially causing the colloidal release peak to be missed. Because existing experimental setups and methods break down experimental steps such as carbonate concentration control and colloid monitoring into discrete, delayed offline operations, they cannot achieve dynamic hydrochemical condition simulation and in-situ colloid-nucleus co-analysis, resulting in limitations in the colloid carrying factor α and dynamic R. d The measured error rate of migration parameters is as high as 30-50%. Therefore, it is urgent to propose a colloidal-mediated nuclide migration behavior simulation and monitoring system to overcome the technical bottlenecks in the study of radionuclide migration behavior in claystone surrounding rocks, such as the instability of migration environment conditions caused by dynamic fluctuations in carbonate concentration and the difficulty in distinguishing the contribution of colloidal carriers in situ. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a colloidal-mediated nuclide migration behavior simulation and monitoring system. The system includes a solution control unit, a dynamic light scattering in-situ analysis unit, a central control unit, a soil column, a vacuum chamber, and a collection device. The solution control unit is connected to the soil column inlet, the soil column outlet is connected to the vacuum chamber inlet, the first vacuum chamber outlet is connected to the collection device, and the second vacuum chamber outlet is connected to the dynamic light scattering in-situ analysis unit via pipelines. The solution control unit is used to monitor and adjust the conductivity, pH value and redox potential of the solution pumped into the soil column in real time, and is connected to the central control unit. The soil column is used to fill the reconstruction medium. The vacuum box is connected to the vacuum pump and is used to vacuum store the effluent from the soil column. The collection device is used to collect the effluent from the soil column. The dynamic light scattering in-situ analysis unit is used to detect the particle size distribution of colloids in the effluent from the soil column.

[0005] Furthermore, the solution control unit includes a gradient mixing chamber for storing the solution pumped into the soil column; the gradient mixing chamber is equipped with a multi-parameter sensing probe for real-time monitoring of the solution's conductivity, pH value, and redox potential; the gradient mixing chamber has multiple replenishment ports, which are connected to multiple replenishment tanks via pipelines, and the replenishment tanks are used to store compensation solution; the gradient mixing chamber outlet is connected to the soil column inlet via a peristaltic pump, and the peristaltic pump pumps the solution in the gradient mixing chamber into the soil column.

[0006] Furthermore, the multi-parameter sensor probe and the valve of the replenishment tank are both connected to the central control unit. When the multi-parameter sensor probe detects that the conductivity, pH value and / or redox potential of the solution deviate from the set threshold, the central control unit opens the valve of the replenishment tank to quantitatively replenish carbonate reserve solution, pH adjuster and / or deionized water into the gradient mixing chamber to ensure the chemical properties of the solution in the gradient mixing chamber are stable.

[0007] Furthermore, the flow rate of the compensation solution is 0.5~5 mL / min, the conductivity control accuracy is ±5 μS / cm, and the pH control accuracy is ±0.05.

[0008] Furthermore, the gradient mixing chamber is equipped with 3 to 5 layers of stacked stainless steel screens at the corresponding replenishment port to impede the mixing of the compensation liquid and the solution, thereby preventing abrupt changes in the local chemical properties of the solution caused by quantitative compensation. The mesh density of the screens is 80 to 120 mesh.

[0009] Furthermore, the dynamic light scattering in-situ analysis unit includes a data processing module, a constant temperature detection chamber, and a sample cell, a laser, and a backscattering detector located within the constant temperature detection chamber; a control valve is provided on the pipeline between the sample cell and the second outlet of the vacuum chamber to control the flow rate of the liquid flowing out of the second outlet of the vacuum chamber to be less than 5 μL / min.

[0010] Furthermore, the sample cell and the control valve are connected by a fused silica capillary, and the inner wall of the capillary is treated with nano-silanization to form a long-chain fluoroalkylsiloxane coating on the inner wall surface.

[0011] Furthermore, the laser is perpendicularly irradiated with an incident angle of 90°±2° into the effluent in the sample cell. The backscatter detector captures the time-varying light intensity fluctuation signal generated by the colloidal particles in the effluent. The data processing module calculates the particle size distribution spectrum based on this signal and outputs a full particle size spectrum of 1~1000nm every 30~60 seconds. When the data processing module detects a sharp peak with a full width at half maximum (FWHM) <15nm and a polydispersity index below 0.1, it is marked as an inorganic colloidal aggregate. When it detects a broad peak with a FWHM >80nm and a light intensity fluctuation variance exceeding 15%, it is marked as an organic pseudocolloid.

[0012] Furthermore, the interior of the soil column is sequentially filled with a porous plate, a reconstructed medium, moistened quartz sand, polyethylene particles, and another porous plate from the inlet to the outlet. The openings at the inlet and outlet of the soil column are sealed with sealing baffles.

[0013] Furthermore, the collection device samples and measures the radionuclide activity of the effluent at fixed time intervals.

[0014] This invention provides a colloidal-mediated nuclide migration behavior simulation and monitoring system. Compared with existing technologies, this invention creatively proposes an improved design of a solution regulation unit and a dynamic light scattering in-situ analysis unit, overcoming the technical bottlenecks in studying the migration behavior of radionuclides in claystone surrounding rocks, such as the instability of migration environment conditions caused by dynamic fluctuations in solution chemical properties like carbonate concentration in groundwater, and the difficulty in in-situ distinguishing the contribution of colloidal carriers. This invention monitors solution chemical parameters in real time by setting a pH / conductivity sensor group at the inflow end of the soil column. When the carbonate concentration or pH value deviates from the set threshold, quantitative automatic compensation is performed, achieving dynamic adjustment of migration environment parameters during nuclide migration simulation and avoiding the hindrance factor R caused by migration environment distortion. d The parameters deviate from the true values. This invention directly couples the dynamic light scattering analysis component to the soil column outlet through a low-adsorption flow path. Combined with synchronously acquired nuclide activity data, it can distinguish in situ the contribution ratio of inorganic colloids and organic pseudocolloids such as humic substances to nuclide migration, realizing dynamic hydrochemical condition simulation and in-situ colloid-nucleus synergistic analysis. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the nuclide migration behavior simulation and monitoring system of the present invention.

[0017] Explanation of reference numerals in the attached figures: 1. Solution control unit; 2. Dynamic light scattering in-situ analysis unit; 3. Soil column; 4. Vacuum chamber; 5. Collection device; 6. Vacuum pump; 7. Gradient mixing chamber; 8. Multi-parameter sensor probe; 9. Liquid replenishment tank; 10. Peristaltic pump; 11. Valve; 12. Screen; 13. Data processing module; 14. Constant temperature detection chamber; 15. Sample cell; 16. Laser; 17. Backscatter detector; 18. Control valve; 19. Quartz capillary tube; 20. Sealing baffle. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0019] Unless otherwise specified, the preferred embodiments of the present invention can be freely combined as needed. Those skilled in the art will understand that the data and various parameters described in the embodiments are merely exemplary and do not constitute a limitation of the present invention. The chemical components and equipment used in the following embodiments are all materials and equipment known in the art, and all materials and equipment used in the present invention can be obtained commercially.

[0020] This invention provides a colloidal-mediated nuclide migration behavior simulation and monitoring system. The system includes a solution control unit 1, a dynamic light scattering in-situ analysis unit 2, a central control unit, a soil column 3, a vacuum chamber 4, and a collection device 5. The solution control unit 1 is connected to the inlet of the soil column 3, the outlet of the soil column 3 is connected to the inlet of the vacuum chamber 4, the first outlet of the vacuum chamber 4 is connected to the collection device 5, and the second outlet of the vacuum chamber 4 is connected to the dynamic light scattering in-situ analysis unit 2 via pipelines. The colloid in this invention refers to particles with a diameter range of 1-1000 nm in a nuclide solution or a simulated groundwater solution containing the target nuclide.

[0021] The solution control unit 1 of this invention is used to monitor and adjust the conductivity, pH value, and redox potential of the solution pumped into the soil column 3 in real time, and is communicatively connected to the central control unit. The soil column 3 is used to fill the reconstruction medium, which can be made of acrylic acid. From the inlet to the outlet, the interior of the soil column 3 is sequentially filled with a porous plate, reconstruction medium, moistened quartz sand, polyethylene particles, and another porous plate. The openings at the inlet and outlet of the soil column 3 are sealed with sealing baffles 20. A vacuum chamber 4 is connected to a vacuum pump 6 and is used to temporarily store the effluent from the soil column 3 under vacuum conditions. A collection device 5 is used to collect the effluent from the soil column 3 and can sample and measure the nuclide activity of the effluent at fixed time intervals. A dynamic light scattering in-situ analysis unit 2 is used to detect the particle size distribution of colloids in the effluent from the soil column 3.

[0022] The solution control unit of this invention includes a gradient mixing chamber 7 for storing the solution pumped into the soil column 3; the gradient mixing chamber 7 is equipped with a multi-parameter sensing probe 8 for real-time monitoring of the solution's conductivity, pH value, and redox potential; the gradient mixing chamber has multiple replenishment ports, which are respectively connected to multiple replenishment tanks 9 by pipelines, and the replenishment tanks 9 are used to store compensation solution; the outlet of the gradient mixing chamber 7 is connected to the inlet of the soil column 3 by a peristaltic pump 10, and the peristaltic pump 10 pumps the solution in the gradient mixing chamber 7 into the soil column 3.

[0023] In this invention, the multi-parameter sensing probe 8 and the valve 11 of the replenishment tank 9 are both communicatively connected to the central control unit. When the multi-parameter sensing probe 8 detects that the conductivity, pH value, and / or redox potential of the solution deviate from the set threshold, the central control unit opens the valve 11 of the replenishment tank 9 to quantitatively replenish carbonate stock solution, pH adjuster, and / or deionized water into the gradient mixing chamber 7, ensuring the chemical stability of the solution within the gradient mixing chamber 7. The flow rate of the replenishment solution injected into the gradient mixing chamber 7 is 0.5~5 mL / min, the conductivity control accuracy is ±5 μS / cm, and the pH control accuracy is ±0.05. The entire control process of this invention requires no manual intervention and can control carbonate concentration fluctuations to levels far lower than those of traditional methods, effectively solving the problem of chemical instability caused by changes in CO2 partial pressure or mineral dissolution. Experimental verification shows that the system of this invention can suppress the concentration fluctuation of a 5 mmol / L carbonate system within ±3% during continuous operation for hundreds of hours, providing a stable environmental background for nuclide migration. The gradient mixing chamber 7 of this invention is provided with 3 to 5 layers of stacked stainless steel screens 12 at the corresponding replenishment port. The mesh density of the screens 12 is 80 to 120 mesh. They are used to impede the mixing of the compensation liquid and the solution, realize the rapid homogenization of the solution, and avoid the interference of the migration process caused by the abrupt change in local chemical properties of the solution due to quantitative compensation.

[0024] The dynamic light scattering in-situ analysis unit 2 of this invention includes a data processing module 13, a constant temperature detection chamber 14, and a sample cell 15, a laser 16, and a backscatter detector 17 located within the constant temperature detection chamber 14. A high-precision control valve 18 is installed on the pipeline between the sample cell 15 and the second outlet of the vacuum chamber, which can control the flow rate of the liquid flowing out of the second outlet of the vacuum chamber to be less than 5 μL / min, diverting about 1% of the liquid flowing out of the soil column 3 from the vacuum chamber 4. Preferably, the sample cell 15 and the control valve 18 are connected by a fused silica capillary 19. The inner wall of the capillary 19 is treated with nano-silanization, thereby forming a long-chain fluoroalkyl siloxane coating on the inner wall surface. The capillary 19 guides the liquid flowing through the control valve 18 into the sample cell 15. In this invention, the thickness of the siloxane coating is preferably 50~100 nm, and the contact angle is >150°. This invention creatively grafts long-chain fluoroalkyl siloxanes onto the surface of a microfluidic system to form a molecular-level hydrophobic barrier. Verified by the neutron reflection method, the microfluidic system of this invention can suppress the adsorption loss rate of typical geological colloids (such as montmorillonite and hematite) to below 2%, which is far lower than that of traditional stainless steel flow paths (adsorption rate >15%), thereby ensuring that colloidal particles maintain their original dispersed state during transport.

[0025] In this invention, the laser 16 in the dynamic light scattering in-situ analysis unit 2 vertically irradiates the effluent in the sample cell 15 at an incident angle of 90°±2°. The backscattering detector 17 captures the time-varying light intensity fluctuation signal generated by colloidal particles in the effluent. The data processing module 13 converts the captured raw light intensity signal through an autocorrelation function and then uses a non-negative least squares (NNLS) inversion algorithm to analyze the particle size distribution spectrum in real time, outputting a full particle size spectrum of 1~1000nm every 30~60 seconds. When the data processing module 13 detects a sharp peak with a full width at half maximum (FWHM) <15nm and a polydispersity index below 0.1, it automatically marks it as an inorganic colloidal aggregate (such as a goethite-silica complex). When it detects a broad peak with a FWHM >80nm and a light intensity fluctuation variance exceeding 15%, it automatically marks it as an organic pseudocolloid (such as a humic acid-plutonium complex). The peak position shift can characterize the influence of humic molecule conformational changes on the radionuclide carrying capacity. The dynamic light scattering in-situ analysis unit 2 of this invention enables continuous dynamic tracking of a multi-component colloidal system under certain chemical conditions of simulated groundwater. By dynamically adjusting the chemical parameters of the solution pumped into the soil column 3, the inhibition mechanism of migrating liquid on the evolution of abnormal colloids can be studied.

[0026] The present invention will now be described in more detail with reference to exemplary embodiments. The following embodiments or experimental data are intended to illustrate the present invention by way of example, and those skilled in the art should understand that the present invention is not limited to these embodiments or experimental data.

[0027] Example 1 The nuclide migration behavior simulation and monitoring system of the present invention is used to simulate the colloidal-mediated nuclide migration behavior.

[0028] 1. Preparation of migration media: Uncirculated soil samples were collected from typical sites and freeze-dried at -10℃ and 0.1 mbar for 48 h. After pulverization, the samples were passed through a 200-mesh sieve to obtain uncirculated soil powder. A porous plate, uncirculated soil powder, moistened quartz sand, polyethylene particles, and another porous plate were sequentially packed into an acrylic soil column from inlet to outlet. The sample powder was compressed until its dry density reached that of the uncirculated soil sample. Then, under vibration frequency of 20–40 Hz and wetting rate of 5–10 mL / min, a combined vibration compaction and solution wetting process was used to reconstruct the migration medium. The vibration time was 30 min, and the wetting time was 2 min. During the packing of the uncirculated soil powder, inert markers were placed in layers along the axial direction of the soil column for post-experiment spatial positioning verification. The inert markers were arrays of tantalum metal wires with a diameter of 0.1 mm, a spacing of 10 mm, and an embedding depth of 1 / 2 the radius of the soil column.

[0029] 2. Nuclide migration experiment: Using a simulated groundwater solution containing Cs-137 as the nuclide solution, the simulated groundwater is a neutral aqueous solution with the following ionic strength: Na + =20mg / L, K + =5mg / L, Ca 2+ =40mg / L, Mg 2+ =10mg / L, Cl - =25mg / L, SO4 2- =30mg / L, HCO3 - =150 mg / L, the specific activity of Cs-137 in the radionuclide solution is 10. 5 Bq / mL. The radionuclide solution is loaded into the gradient mixing chamber 7 of the solution control unit 1. The peristaltic pump 10 continuously pumps the radionuclide solution into the soil column 3 at a flow rate of 3 mL / d. The radionuclide solution penetrates the migration medium, flows out of the soil column 3 and enters the vacuum chamber 4 with a vacuum degree of -5 MPa.

[0030] A multi-parameter sensor probe 8 monitors the conductivity, pH value, and redox potential of the radionuclide solution within the gradient mixing chamber 7 in real time. When the multi-parameter sensor probe 8 detects that the conductivity, pH value, and / or redox potential of the radionuclide solution deviate from the set threshold, the central control unit opens valve 11 of the replenishment tank 9 to quantitatively replenish carbonate stock solution, pH adjuster, deionized water, and / or radionuclide solution into the gradient mixing chamber 7, ensuring the chemical stability of the radionuclide solution within the gradient mixing chamber 7. The flow rate of the replenishment solution injected into the gradient mixing chamber 7 is 0.5 mL / min, with a conductivity control accuracy of ±5 μS / cm and a pH control accuracy of ±0.05. Three layers of stacked stainless steel mesh 12 are installed at the replenishment port within the gradient mixing chamber 7. The mesh density of the mesh 12 is 120 mesh, used to achieve rapid homogenization of the radionuclide solution and avoid interference from local chemical abrupt changes in the radionuclide solution caused by quantitative compensation on the migration process.

[0031] The effluent from vacuum chamber 4 flows through a high-precision control valve 18 via a second outlet and enters the sample cell 15 located within the constant-temperature detection chamber 14 via a capillary tube 19. The high-precision control valve 18 ensures that the flow rate of the effluent from the second outlet of vacuum chamber 4 is less than 5 μL / min. The capillary tube 19 is a fused silica capillary tube, and its inner wall is treated with nano-silanization, forming a 100 nm thick long-chain fluoroalkylsiloxane coating on the inner wall surface with a contact angle >150°. The effluent from vacuum chamber 4 enters the collection device 5 via a first outlet.

[0032] The dynamic light scattering in-situ analysis unit 2 is started to continuously scan the colloidal particle size spectrum. The collection device 5 is started simultaneously to cumulatively measure the activity of nuclides in the effluent. The cumulative activity of nuclides in the effluent is measured at 30-minute intervals. Thus, the contribution rate of the colloidal carrier can be calculated every 30-minute interval.

[0033] The operation of continuous scanning of colloidal particle size distribution is as follows: the laser 16 is perpendicularly irradiated into the effluent in the sample cell 15 at an incident angle of 90°±2°. The backscatter detector 17 captures the time-varying light intensity fluctuation signal generated by the colloidal particles in the effluent. The data processing module 13 converts the captured raw light intensity signal through an autocorrelation function and then uses a non-negative least squares inversion algorithm to analyze the particle size distribution spectrum in real time, outputting a full particle size spectrum of 1~1000nm every 60 seconds. When the data processing module 13 detects a sharp peak with a full width at half maximum (FWHM) <15nm and a polydispersity index below 0.1, it is automatically labeled as an inorganic colloidal aggregate; when it detects a broad peak with a FWHM >80nm and a light intensity fluctuation variance exceeding 15%, it is automatically labeled as an organic pseudocolloid.

[0034] The materials and equipment used in this invention are all commercially available. The above description is only a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A colloid mediated nuclide migration behavior simulation and monitoring system, characterized by, The system comprises a solution regulating unit, a dynamic light scattering in-situ analysis unit, a central control unit, a soil column, a vacuum box and a collection device. The solution regulating unit is connected by pipelines with the inlet of the soil column, the outlet of the soil column, the inlet of the vacuum box, the first outlet of the vacuum box and the collection device, the second outlet of the vacuum box and the dynamic light scattering in-situ analysis unit. The solution regulating unit is used for real-time monitoring and adjusting the conductivity, pH value and oxidation-reduction potential of the solution pumped into the soil column and is in communication connection with the central control unit; the soil column is used for loading a reconstruction medium; the vacuum box is connected with a vacuum pump and is used for vacuum storing the effluent of the soil column; and the collection device is used for collecting the effluent of the soil column. The dynamic light scattering in-situ analysis unit is used for detecting the particle size distribution of colloids in the effluent of the soil column.

2. The colloid mediated nuclide migration behavior simulation and monitoring system of claim 1, wherein, The solution regulating unit comprises a gradient mixing cavity for storing the solution pumped into the soil column; a multi-parameter sensing probe is arranged in the gradient mixing cavity for real-time monitoring the conductivity, pH value and oxidation-reduction potential of the solution; the gradient mixing cavity is provided with a plurality of liquid supplementing openings which are connected by pipelines with a plurality of liquid supplementing tanks for storing compensation liquid; and the outlet of the gradient mixing cavity is connected by a pipeline with the inlet of the soil column through a peristaltic pump for pumping the solution in the gradient mixing cavity into the soil column.

3. The colloid mediated nuclide migration behavior simulation and monitoring system of claim 2, wherein, The multi-parameter sensing probe and the valves of the liquid supplementing tanks are in communication connection with the central control unit, and when the multi-parameter sensing probe detects that the conductivity, pH value and / or oxidation-reduction potential of the solution deviates from the set threshold value, the central control unit opens the valves of the liquid supplementing tanks to quantitatively supplement carbonate reserve liquid, pH adjuster and / or deionized water into the gradient mixing cavity, so as to ensure the stability of the chemical properties of the solution in the gradient mixing cavity.

4. The colloidal mediated migratory behavior of nuclides simulation and monitoring system of claim 3, wherein, The flow rate of the compensation liquid is 0.5-5 mL / min, the conductivity control accuracy is ±5 μS / cm, and the pH control accuracy is ±0.

05.

5. The colloidal mediated migratory behavior of nuclides simulation and monitoring system of claim 3, wherein, Three to five layers of stacked stainless steel screens are arranged at the positions corresponding to the liquid supplementing openings in the gradient mixing cavity for blocking the mixing of the compensation liquid and the solution and avoiding the local chemical property mutation of the solution caused by the quantitative compensation, and the mesh density of the screens is 80-120 meshes.

6. The colloidal mediated migratory behavior of nuclides simulation and monitoring system of claim 1, wherein, The dynamic light scattering in-situ analysis unit comprises a data processing module, a constant-temperature detection cabin and a sample cell, a laser and a backscattering detector arranged in the constant-temperature detection cabin; a control valve is arranged on the pipeline between the sample cell and the second outlet of the vacuum box to control the flow rate of the effluent of the second outlet of the vacuum box to be less than 5 μL / min.

7. The colloidal mediated migratory behavior of nuclides simulation and monitoring system of claim 6, wherein, The sample cell and the control valve are communicated by a fused quartz capillary, and the inner wall of the capillary is subjected to nanosiliconization treatment to form a long-chain fluoralkylsiloxane coating on the surface of the inner wall.

8. The colloidal mediated migratory behavior of nuclides simulation and monitoring system of claim 6, wherein, The laser vertically irradiates effluent in the sample cell at an incident angle of 90°±2°, a backscattering detector captures time-varying light intensity fluctuation signals generated by colloidal particles in the effluent, and a data processing module calculates a particle size distribution spectrum therefrom, outputting a full particle size spectrum of 1-1000 nm every 30-60 seconds; when the data processing module detects a sharp peak with a half-height width of <15 nm and a polydispersity index of <0.1, it is marked as inorganic colloidal aggregates; when a broad peak with a half-height width of >80 nm is detected and the light intensity fluctuation variance exceeds 15%, it is marked as organic pseudo-colloids.

9. The colloidal mediated migratory behavior of nuclides simulation and monitoring system of claim 1, wherein, The soil column is internally filled with, in sequence from the inlet to the outlet, a porous plate, a reconstruction medium, wet quartz sand, polyethylene particles and a porous plate, and the openings of the inlet and the outlet of the soil column are respectively blocked by sealing baffles.

10. The colloidal mediated nuclide migration behavior simulation and monitoring system of claim 1, wherein, The collection device samples and measures the radionuclide activity of the effluent at fixed time intervals.

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