A diffusion device and method for radionuclide migration experiments in an underground laboratory

Abstract

The present invention belongs to the technical field of underground laboratory nuclide migration test, and specifically relates to a diffusion device and method for underground laboratory nuclide migration test. The device is used for a long-term diffusion test of nuclides in groundwater in an underground laboratory nuclide migration test, wherein the groundwater is groundwater obtained from a borehole at the location of an underground laboratory for deep geological safe disposal of high-level radioactive waste, wherein the diffusion device is installed in a long-term monitoring device for nuclide migration in an underground laboratory, and comprises a source liquid pool (5) connected to the groundwater, the source liquid pool (5) being connected to a sampling pool (7) through a diffusion medium (6), the source liquid pool (5) being used to obtain a source liquid, the source liquid being obtained by mixing a tracer or a nuclide with groundwater, the sampling pool (7) being used to sample a sample liquid, the sample liquid being a liquid that diffuses from the source liquid pool (5) through a diffusion medium (6) and enters the sampling pool (7). The present invention will provide a scientific basis for the safety evaluation of a deep geological disposal repository.

Description

Technical Field

[0001] The invention belongs to the technical field of underground laboratory nuclide migration test, and in particular relates to a diffusion device and method for underground laboratory nuclide migration test. Background Art

[0002] Before the implementation of deep geological disposal of high-level radioactive waste, safety analysis and evaluation of the pre-selected site and deep geological disposal repository are required. The construction of underground laboratories and field tests can provide the most direct technical and experience support for the design, construction, operation and safety evaluation analysis of deep geological disposal repositories. Among them, the diffusion experiment device is a necessary tool for studying the migration behavior of solutes in porous media due to chemical potential. In ordinary laboratories, general diffusion experiments are very convenient to operate manually, but in underground laboratories, the scale of porous media is much larger than that of ordinary ground laboratories. Long-term sealing technology and automatic control technology are required to carry out research on the migration and diffusion of nuclides in underground laboratories. The development of diffusion devices and methods in the field monitoring equipment of underground laboratory nuclide migration tests makes long-term diffusion tests of nuclides in undisturbed groundwater possible, and the data obtained will provide a more reliable scientific basis for the safety evaluation of deep geological disposal repositories. At present, there are no such devices and methods in China. Summary of the invention

[0003] The purpose of the present invention is to provide a diffusion device and method for long-term monitoring equipment of nuclide migration in underground laboratories, so as to solve the problem of long-term diffusion of nuclides in undisturbed groundwater in underground laboratories.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is a diffusion device for underground laboratory nuclide migration test, which is used for long-term diffusion test of nuclides in groundwater in underground laboratory nuclide migration test, the groundwater is groundwater obtained from a borehole at the location of an underground laboratory for deep geological safety disposal of high-level radioactive waste, and is installed in the long-term monitoring equipment of nuclide migration in the underground laboratory, including a source liquid pool connected to the groundwater, the source liquid pool is connected to the sampling pool through a diffusion medium, the source liquid pool is used to obtain source liquid, the source liquid is obtained by mixing a tracer or a nuclide with the groundwater, the sampling pool is used to sample the sample liquid, and the sample liquid refers to the liquid that diffuses from the source liquid pool through the diffusion medium and enters the sampling pool.

[0005] further,

[0006] The source liquid pool is connected to the original groundwater inlet on the long-term monitoring device for nuclide migration in the underground laboratory through a first pipeline, and the groundwater enters the source liquid pool through the original groundwater inlet and the first pipeline;

[0007] A peristaltic pump, a first solenoid valve and a second solenoid valve are sequentially arranged in series on the first pipeline from the original groundwater inlet to the source liquid pool;

[0008] The second solenoid valve is also connected to the sampling pool through a second pipeline;

[0009] The first solenoid valve is a two-position two-way solenoid valve, and the second solenoid valve is a two-position three-way solenoid valve.

[0010] further,

[0011] It also includes a first waste liquid pool, which is connected to the source liquid pool through a third pipeline;

[0012] A third solenoid valve and a fourth solenoid valve are sequentially arranged in series on the third pipeline from the source liquid pool to the first waste liquid pool;

[0013] The third solenoid valve is also connected to the sampling pool through a fourth pipeline;

[0014] The third solenoid valve is a two-position three-way solenoid valve, and the fourth solenoid valve is a two-position two-way solenoid valve.

[0015] further,

[0016] Also includes a second switching valve, wherein the second switching valve is connected to the sampling pool through a fifth pipeline;

[0017] An eighth solenoid valve and a second injection pump are sequentially arranged in series on the fifth pipeline from the sampling pool to the second switching valve;

[0018] The second switching valve is also connected to the first waste liquid tank through a sixth pipeline;

[0019] The second switching valve is also connected to the second sample bottle through a seventh pipeline;

[0020] The eighth solenoid valve is a two-position two-way solenoid valve.

[0021] further,

[0022] It also includes a first switching valve, which is connected to the source liquid pool through a ninth pipeline;

[0023] A sixth solenoid valve and a first injection pump are sequentially arranged in series on the ninth pipeline from the source liquid pool to the first switching valve;

[0024] The first switching valve is also connected to the first sample bottle through a tenth pipeline;

[0025] The first switching valve is also connected to the second waste liquid tank through an eleventh pipeline;

[0026] The sixth solenoid valve is a two-position two-way solenoid valve.

[0027] further,

[0028] It also includes a nitrogen pump, which is connected to the source liquid pool through a twelfth pipeline, and a fifth solenoid valve is provided on the twelfth pipeline, and the fifth solenoid valve is a two-position two-way solenoid valve;

[0029] The nitrogen pump is also connected to the sampling pool through a thirteenth pipeline, and a seventh solenoid valve is arranged on the thirteenth pipeline, and the seventh solenoid valve is a two-position two-way solenoid valve;

[0030] The nitrogen pump is also connected to the first switching valve through a fourteenth pipeline;

[0031] It also includes a fifteenth pipeline connected to the fourteenth pipeline, and the nitrogen pump is connected to the second switching valve through the fourteenth pipeline and the fifteenth pipeline.

[0032] Furthermore, it also includes an eighth pipeline, through which the source liquid pool is connected to the tracer filling device in the underground laboratory nuclide migration long-term monitoring equipment to obtain the tracer.

[0033] Furthermore, it also includes a sixteenth pipeline, through which the source liquid pool is connected to the dissolution device in the underground laboratory nuclide migration long-term monitoring equipment for obtaining the nuclide.

[0034] To achieve the above objectives, the present invention also discloses a diffusion method for an underground laboratory nuclide migration test using a diffusion device for an underground laboratory nuclide migration test as described above, comprising the following steps:

[0035] Step S1, exhausting the source liquid pool and the sampling pool;

[0036] Step S2, injecting water into the source liquid pool and the sampling pool;

[0037] Step S3, injecting the tracer into the source liquid pool and taking samples;

[0038] Step S4, diffusion and sampling of the tracer;

[0039] Step S5, injecting the nuclide into the source liquid pool and taking samples;

[0040] Step S6, diffusion and sampling of the nuclides.

[0041] further,

[0042] In the step S1, the specific operations include: opening the fifth solenoid valve, the seventh solenoid valve, the third solenoid valve and the fourth solenoid valve, replacing the air in the source liquid pool and the sampling pool with high-purity nitrogen through the nitrogen pump, wherein the high-purity nitrogen refers to nitrogen with a purity of 99.99%; exhausting the excess gas in the source liquid pool and the sampling pool into the first waste liquid pool, and then closing all valves;

[0043] In the step S2, the specific operations include: opening the first solenoid valve, the second solenoid valve, the third solenoid valve and the fourth solenoid valve, using the peristaltic pump to make the groundwater permeate through the source liquid pool and the sampling pool, draining the excess groundwater in the source liquid pool and the sampling pool into the first waste liquid pool, and then closing all valves;

[0044] In the step S3, the specific operations include: adding the tracer into the source liquid pool by using the tracer filling device, and after the concentration of the tracer in the source liquid pool is uniform, opening the fifth solenoid valve and the sixth solenoid valve, extracting part of the source liquid by using the first injection pump, and then closing the fifth solenoid valve and the sixth solenoid valve, opening the first switching valve to switch to the second waste liquid pool, and discharging part of the source liquid in the first injection pump into the second waste liquid pool; then switching the first switching valve to the first sample bottle, and discharging part of the source liquid in the first injection pump into the first sample bottle; then switching the first switching valve to the second waste liquid pool to reset the first injection pump; finally using the nitrogen pump to blow out the residual liquid in the first switching valve, and closing all valves;

[0045] In the step S4, the specific operations include: after the step S3 is completed, after one to five years, the tracer in the source liquid pool diffuses into the sampling pool through the diffusion medium; the sampling pool is sampled regularly, the seventh solenoid valve and the eighth solenoid valve are opened, and part of the sample liquid in the sampling pool is extracted by the second injection pump, the seventh solenoid valve and the eighth solenoid valve are closed, the second switching valve is opened to switch to the first waste liquid pool, and part of the sample liquid in the second injection pump is discharged into the first waste liquid pool; the second switching valve is then switched to the second sample bottle, and part of the sample liquid in the second injection pump is discharged into the second sample bottle; the second switching valve is then switched to the first waste liquid pool to reset the second injection pump; finally, the residual liquid in the second switching valve is blown out by the nitrogen pump, and all valves are closed;

[0046] In the step S5, the specific operations include: after the step S4 is completed, the nuclide is added to the source liquid pool by using the dissolving device, and after the concentration of the nuclide in the source liquid pool is uniform, the fifth solenoid valve and the sixth solenoid valve are opened, and part of the source liquid is extracted by using the first injection pump, and the fifth solenoid valve and the sixth solenoid valve are closed, and the first switching valve is opened to switch to the second waste liquid pool, and a part of the source liquid in the first injection pump is discharged into the second waste liquid pool; then the first switching valve is switched to the first sample bottle, and a part of the source liquid in the first injection pump is discharged into the first sample bottle; then the first switching valve is switched to the second waste liquid pool, and the first injection pump is reset; finally, the nitrogen pump is used to blow out the residual liquid in the first switching valve, and all valves are closed;

[0047] In the step S6, the specific operations include: after the completion of the step S5, after five to ten years, the nuclides in the source liquid pool diffuse into the sampling pool through the diffusion medium; regularly sample the sampling pool, open the seventh solenoid valve and the eighth solenoid valve, use the second injection pump to extract part of the sample liquid in the sampling pool, close the seventh solenoid valve and the eighth solenoid valve, open the second switching valve to switch to the first waste liquid pool, and discharge part of the sample liquid in the second injection pump into the first waste liquid pool; then switch the second switching valve to the second sample bottle, and discharge part of the sample liquid in the second injection pump into the second sample bottle; then switch the second switching valve to the first waste liquid pool to reset the second injection pump; finally, use the nitrogen pump to blow out the residual liquid in the second switching valve and close all valves.

[0048] The beneficial effects of the present invention are:

[0049] 1. The device and method provided by the present invention can be used for long-term diffusion tests of tracers and nuclides in hypoxic groundwater in real geological environments, and test samples can be automatically collected under hypoxic conditions. The data obtained will provide a scientific basis for the safety evaluation of deep geological disposal repositories.

[0050] 2. The device provided by the present invention is in the shape of an elongated cylinder, which matches the borehole in the underground laboratory and is suitable for long-term experimental research in the underground laboratory.

[0051] 3. The device provided by the present invention adopts an automatic control system to achieve long-term control, and an exhaust device and a cleaning and emptying procedure are added to the design to ensure the authenticity and reliability of the collected data.

[0052] 4. The present invention can utilize the nuclide solution (source solution) of the nuclide solubility test in step S5 to perform a diffusion test (the diffusion test is performed in step S6). BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of a diffusion device for underground laboratory nuclide migration test described in a specific embodiment of the present invention;

[0054] In the figure: 1-original groundwater inlet, 2-peristaltic pump, 3-first solenoid valve (two-position two-way solenoid valve), 4-second solenoid valve (two-position three-way solenoid valve), 5-source liquid pool, 6-diffusion medium, 7-sampling pool, 8-third solenoid valve (two-position three-way solenoid valve), 9-fourth solenoid valve (two-position two-way solenoid valve), 10-first waste liquid pool, 11-tracer filling device, 12-nitrogen pump, 13-fifth solenoid valve (two-position two-way solenoid valve), 14-sixth solenoid valve (two-position two-way solenoid valve), 15-first injection pump, 16-first switching valve, 17-first sample bottle, 18-second waste liquid pool, 19-the seventh solenoid valve (two-position two-way solenoid valve), 20-the eighth solenoid valve (two-position two-way solenoid valve), 21-the second injection pump, 22-the second switching valve, 23-the second sample bottle, 24-the dissolution device, 25-the first pipeline, 26-the second pipeline, 27-the third pipeline, 28-the fourth pipeline, 29-the fifth pipeline, 30-the sixth pipeline, 31-the seventh pipeline, 32-the eighth pipeline, 33-the ninth pipeline, 34-the tenth pipeline, 35-the eleventh pipeline, 36-the twelfth pipeline, 37-the thirteenth pipeline, 38-the fourteenth pipeline, 39-the fifteenth pipeline, 40-the sixteenth pipeline. DETAILED DESCRIPTION

[0055] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0056] The present invention provides a diffusion device for underground laboratory nuclide migration test (see Figure 1 ), used for long-term diffusion test of nuclides in groundwater in underground laboratory nuclide migration test, the groundwater is groundwater obtained from a borehole at the location of an underground laboratory for deep geological safety disposal of high-level radioactive waste, and is installed in a long-term monitoring device for nuclide migration in an underground laboratory (the diffusion device provided by the present invention is placed in a borehole with an inner diameter of 95 mm, and is connected to groundwater, a tracer filling device 11, a dissolution device 24 and an electronic and pressure control system led out of a high-pressure plugging and sealing system in the long-term monitoring device for nuclide migration in an underground laboratory through a pipeline), including a source liquid pool 5 connected to the groundwater, the source liquid pool 5 is connected to a sampling pool 7 through a diffusion medium 6, the source liquid pool 5 is used to obtain a source liquid, the source liquid is obtained by mixing a tracer or a nuclide with groundwater, the sampling pool 7 is used to sample the sample liquid, and the sample liquid refers to the liquid that diffuses from the source liquid pool 5 through the diffusion medium 6 and enters the sampling pool 7.

[0057] The source liquid pool 5 is connected to the original groundwater inlet 1 on the long-term monitoring device for nuclide migration in the underground laboratory through the first pipeline 25, and the groundwater enters the source liquid pool 5 through the original groundwater inlet 1 and the first pipeline 25;

[0058] A peristaltic pump 2, a first solenoid valve 3 and a second solenoid valve 4 are sequentially arranged in series on the first pipeline 25 from the original groundwater inlet 1 to the source liquid pool 5;

[0059] The second solenoid valve 4 is also connected to the sampling pool 7 via a second pipeline 26;

[0060] The first solenoid valve 3 is a two-position two-way solenoid valve, and the second solenoid valve 4 is a two-position three-way solenoid valve.

[0061] It also includes a first waste liquid pool 10, which is connected to the source liquid pool 5 through a third pipeline 27;

[0062] A third solenoid valve 8 and a fourth solenoid valve 9 are sequentially arranged in series on the third pipeline 27 from the source liquid pool 5 to the first waste liquid pool 10;

[0063] The third solenoid valve 8 is also connected to the sampling pool 7 via a fourth pipeline 28;

[0064] The third solenoid valve 8 is a two-position three-way solenoid valve, and the fourth solenoid valve 9 is a two-position two-way solenoid valve.

[0065] It also includes a second switching valve 22, which is connected to the sampling pool 7 through a fifth pipeline 29;

[0066] The fifth pipeline 29 is provided with an eighth solenoid valve 20 and a second injection pump 21 in series from the sampling pool 7 to the second switching valve 22;

[0067] The second switching valve 22 is also connected to the first waste liquid tank 10 through a sixth pipeline 30;

[0068] The second switching valve 22 is also connected to the second sample bottle 23 via a seventh pipeline 31;

[0069] The eighth solenoid valve 20 is a two-position two-way solenoid valve.

[0070] It also includes a first switching valve 16, which is connected to the source liquid pool 5 through a ninth pipeline 33;

[0071] A sixth solenoid valve 14 and a first injection pump 15 are sequentially arranged in series on the ninth pipeline 33 from the source liquid pool 5 to the first switching valve 16;

[0072] The first switching valve 16 is also connected to the first sample bottle 17 via the tenth pipeline 34;

[0073] The first switching valve 16 is also connected to the second waste liquid tank 18 through the eleventh pipeline 35;

[0074] The sixth solenoid valve 14 is a two-position two-way solenoid valve.

[0075] The nitrogen pump 12 is also included. The nitrogen pump 12 is connected to the source liquid pool 5 through a twelfth pipeline 36. A fifth solenoid valve 13 is provided on the twelfth pipeline 36. The fifth solenoid valve 13 is a two-position two-way solenoid valve.

[0076] The nitrogen pump 12 is also connected to the sampling pool 7 through a thirteenth pipeline 37. A seventh solenoid valve 19 is provided on the thirteenth pipeline 37. The seventh solenoid valve 19 is a two-position two-way solenoid valve.

[0077] The nitrogen pump 12 is also connected to the first switching valve 16 via a fourteenth pipeline 38;

[0078] The device further includes a fifteenth pipeline 39 connected to the fourteenth pipeline 38 , and the nitrogen pump 12 is connected to the second switching valve 22 via the fourteenth pipeline 38 and the fifteenth pipeline 39 .

[0079] It also includes an eighth pipeline 32, through which the source liquid pool 5 is connected to the tracer filling device 11 in the underground laboratory nuclide migration long-term monitoring equipment for obtaining the tracer.

[0080] It also includes a sixteenth pipeline 40, through which the source liquid pool 5 is connected to the dissolution device 24 in the underground laboratory nuclide migration long-term monitoring equipment for obtaining nuclides.

[0081] The present invention also discloses a diffusion method for an underground laboratory nuclide migration test, which is used for the diffusion device for the underground laboratory nuclide migration test as described above, and comprises the following steps:

[0082] Step S1, exhausting the source liquid pool 5 and the sampling pool 7;

[0083] Step S2, injecting water into the source liquid pool 5 and the sampling pool 7;

[0084] Step S3, injecting a tracer into the source liquid pool 5 and taking samples;

[0085] Step S4, diffusion and sampling of tracer;

[0086] Step S5, injecting nuclides into the source liquid pool 5 and taking samples;

[0087] Step S6, diffusion and sampling of nuclides.

[0088] In step S1, the specific operations include: opening the fifth solenoid valve 13, the seventh solenoid valve 19, the third solenoid valve 8 and the fourth solenoid valve 9, replacing the air in the source liquid pool 5 and the sampling pool 7 with high-purity nitrogen through the nitrogen pump 12, and the high-purity nitrogen refers to nitrogen with a purity of 99.99%; the excess gas in the source liquid pool 5 and the sampling pool 7 is discharged into the first waste liquid pool 10, and then all valves are closed;

[0089] In step S2, the specific operations include: opening the first solenoid valve 3, the second solenoid valve 4, the third solenoid valve 8 and the fourth solenoid valve 9, using the peristaltic pump 2 to allow the groundwater to slowly penetrate through the source liquid pool 5 and the sampling pool 7, and draining the excess groundwater in the source liquid pool 5 and the sampling pool 7 into the first waste liquid pool 10, and then closing all valves;

[0090] In step S3, the specific operations include: adding the tracer into the source liquid pool 5 by using the tracer filling device 11, and after the concentration of the tracer in the source liquid pool 5 is uniform, opening the fifth solenoid valve 13 and the sixth solenoid valve 14, extracting part of the source liquid by using the first injection pump 15, and then closing the fifth solenoid valve 13 and the sixth solenoid valve 14, opening the first switching valve 16 to switch to the second waste liquid pool 18, and discharging a part (a small amount) of the source liquid in the first injection pump 15 into the second waste liquid pool 18; then switching the first switching valve 16 to the first sample bottle 17, and discharging a part (quantitative amount) of the source liquid in the first injection pump 15 into the first sample bottle 17; then switching the first switching valve 16 to the second waste liquid pool 18, and resetting the first injection pump 15; finally, using the nitrogen pump 12 to blow out the residual liquid in the first switching valve 16, and closing all valves;

[0091] In step S4, the specific operations include: after the completion of step S3, after one to five years, the tracer in the source liquid pool 5 diffuses into the sampling pool 7 through the diffusion medium 6; regularly sampling the sampling pool 7, opening the seventh solenoid valve 19 and the eighth solenoid valve 20, using the second injection pump 21 to extract part of the sample liquid in the sampling pool 7, closing the seventh solenoid valve 19 and the eighth solenoid valve 20, opening the second switching valve 22 to switch to the first waste liquid pool 10, and discharging a part (a small amount) of the sample liquid in the second injection pump 21 into the first waste liquid pool 10; then switching the second switching valve 22 to the second sample bottle 23, discharging a part (quantitative amount) of the sample liquid in the second injection pump 21 into the second sample bottle 23; then switching the second switching valve 22 to the first waste liquid pool 10, resetting the second injection pump 21; finally using the nitrogen pump 12 to blow out the residual liquid in the second switching valve 22, and closing all valves;

[0092] In step S5, the specific operation includes: after step S4 (tracer diffusion test) is completed, the nuclide is added to the source liquid pool 5 by using the dissolving device 24, and after the concentration of the nuclide in the source liquid pool 5 is uniform, the fifth solenoid valve 13 and the sixth solenoid valve 14 are opened, and part of the source liquid is extracted by using the first injection pump 15, and the fifth solenoid valve 13 and the sixth solenoid valve 14 are closed, and the first switching valve 16 is opened to switch to the second waste liquid pool 18, and a part (a small amount) of the source liquid in the first injection pump 15 is discharged into the second waste liquid pool 18; then the first switching valve 16 is switched to the first sample bottle 17, and a part (quantitative amount) of the source liquid in the first injection pump 15 is discharged into the first sample bottle 17; then the first switching valve 16 is switched to the second waste liquid pool 18, and the first injection pump 15 is reset; finally, the nitrogen pump 12 is used to blow out the residual liquid in the first switching valve 16, and all valves are closed;

[0093] In step S6, the specific operations include: after the completion of step S5, after five to ten years, the nuclides in the source liquid pool 5 diffuse into the sampling pool 7 through the diffusion medium 6; regularly sample the sampling pool 7, open the seventh solenoid valve 19 and the eighth solenoid valve 20, use the second injection pump 21 to extract part of the sample liquid in the sampling pool 7, close the seventh solenoid valve 19 and the eighth solenoid valve 20, open the second switching valve 22 to switch to the first waste liquid pool 10, and discharge a part (a small amount) of the sample liquid in the second injection pump 21 into the first waste liquid pool 10; then switch the second switching valve 22 to the second sample bottle 23, and discharge a part (quantitative) of the sample liquid in the second injection pump 21 into the second sample bottle 23; then switch the second switching valve 22 to the first waste liquid pool 10 to reset the second injection pump 21; finally, use the nitrogen pump 12 to blow out the residual liquid in the second switching valve 22, and close all valves.

[0094] The device described in the present invention is not limited to the embodiments described in the specific implementation manner. Those skilled in the art may derive other implementation manners based on the technical solution of the present invention, which also fall within the technical innovation scope of the present invention.

Claims

1. A diffusion device for underground laboratory nuclide migration test, used for long-term diffusion test of nuclides in groundwater in underground laboratory nuclide migration test, wherein the groundwater is groundwater obtained from a borehole at the location of an underground laboratory for deep geological safety disposal of high-level radioactive waste, and is characterized by: Installed in an underground laboratory radionuclide migration long-term monitoring device, comprising a source liquid pool (5) connected to the groundwater, and also comprising a tracer filling device (11) and a dissolving device (24), wherein the source liquid pool (5) is connected to a sampling pool (7) via a diffusion medium (6), wherein the source liquid pool (5) is used to obtain a source liquid, wherein the source liquid is obtained by mixing a tracer or a radionuclide with the groundwater, and wherein the sampling pool (7) is used to sample a sample liquid, wherein the sample liquid refers to a liquid that diffuses from the source liquid pool (5) through the diffusion medium (6) and enters the sampling pool (7); The source liquid pool (5) is connected to the original groundwater inlet (1) on the underground laboratory nuclide migration long-term monitoring device via a first pipeline (25), and the groundwater enters the source liquid pool (5) via the original groundwater inlet (1) and the first pipeline (25); A peristaltic pump (2), a first solenoid valve (3) and a second solenoid valve (4) are sequentially arranged in series on the first pipeline (25) from the original groundwater inlet (1) to the source liquid pool (5); The second solenoid valve (4) is also connected to the sampling pool (7) via a second pipeline (26); The first solenoid valve (3) is a two-position two-way solenoid valve, and the second solenoid valve (4) is a two-position three-way solenoid valve; It also includes a first waste liquid pool (10), wherein the first waste liquid pool (10) is connected to the source liquid pool (5) via a third pipeline (27); A third solenoid valve (8) and a fourth solenoid valve (9) are sequentially arranged in series on the third pipeline (27) from the source liquid pool (5) to the first waste liquid pool (10); The third solenoid valve (8) is also connected to the sampling pool (7) via a fourth pipeline (28); The third solenoid valve (8) is a two-position three-way solenoid valve, and the fourth solenoid valve (9) is a two-position two-way solenoid valve; It also includes a second switching valve (22), wherein the second switching valve (22) is connected to the sampling pool (7) via a fifth pipeline (29); An eighth solenoid valve (20) and a second injection pump (21) are sequentially arranged in series on the fifth pipeline (29) from the sampling pool (7) to the second switching valve (22); The second switching valve (22) is also connected to the first waste liquid pool (10) via a sixth pipeline (30); The second switching valve (22) is also connected to the second sample bottle (23) via a seventh pipeline (31); The eighth solenoid valve (20) is a two-position two-way solenoid valve; It also includes a first switching valve (16), wherein the first switching valve (16) is connected to the source liquid pool (5) via a ninth pipeline (33); The ninth pipeline (33) is provided with a sixth solenoid valve (14) and a first injection pump (15) in series from the source liquid pool (5) to the first switching valve (16); The first switching valve (16) is also connected to the first sample bottle (17) via a tenth pipeline (34); The first switching valve (16) is also connected to the second waste liquid tank (18) via an eleventh pipeline (35); The sixth solenoid valve (14) is a two-position two-way solenoid valve; It also includes a nitrogen pump (12), the nitrogen pump (12) is connected to the source liquid pool (5) via a twelfth pipeline (36), a fifth solenoid valve (13) is provided on the twelfth pipeline (36), and the fifth solenoid valve (13) is a two-position two-way solenoid valve; The nitrogen pump (12) is also connected to the sampling pool (7) via a thirteenth pipeline (37), and a seventh solenoid valve (19) is provided on the thirteenth pipeline (37), and the seventh solenoid valve (19) is a two-position two-way solenoid valve; The nitrogen pump (12) is also connected to the first switching valve (16) via a fourteenth pipeline (38); It also includes a fifteenth pipeline (39) connected to the fourteenth pipeline (38), and the nitrogen pump (12) is connected to the second switching valve (22) through the fourteenth pipeline (38) and the fifteenth pipeline (39).

2. The diffusion device for underground laboratory nuclide migration test as claimed in claim 1, characterized in that: It also includes an eighth pipeline (32), through which the source liquid pool (5) is connected to the tracer filling device (11) in the underground laboratory nuclide migration long-term monitoring equipment for obtaining the tracer.

3. A diffusion device for underground laboratory nuclide migration test as claimed in claim 2, characterized in that: It also includes a sixteenth pipeline (40), through which the source liquid pool (5) is connected to the dissolution device (24) in the underground laboratory nuclide migration long-term monitoring equipment for obtaining the nuclide.

4. A diffusion method for underground laboratory nuclide migration test for a diffusion device for underground laboratory nuclide migration test as claimed in claim 3, comprising the following steps: Step S1, exhausting the source liquid pool (5) and the sampling pool (7); Step S2, injecting water into the source liquid pool (5) and the sampling pool (7); Step S3, injecting the tracer into the source liquid pool (5) and taking samples; Step S4, diffusion and sampling of the tracer; Step S5, injecting the nuclide into the source liquid pool (5) and taking samples; Step S6, diffusion and sampling of the nuclides.

5. The diffusion method for underground laboratory nuclide migration test as claimed in claim 4, characterized in that: In the step S1, the specific operations include: opening the fifth solenoid valve (13), the seventh solenoid valve (19), the third solenoid valve (8) and the fourth solenoid valve (9), replacing the air in the source liquid pool (5) and the sampling pool (7) with high-purity nitrogen through the nitrogen pump (12), wherein the high-purity nitrogen refers to nitrogen with a purity of 99.99%; exhausting the excess gas in the source liquid pool (5) and the sampling pool (7) into the first waste liquid pool (10), and then closing all valves; In the step S2, the specific operations include: opening the first solenoid valve (3), the second solenoid valve (4), the third solenoid valve (8) and the fourth solenoid valve (9), using the peristaltic pump (2) to allow the groundwater to infiltrate and flow through the source liquid pool (5) and the sampling pool (7), draining the excess groundwater in the source liquid pool (5) and the sampling pool (7) into the first waste liquid pool (10), and then closing all valves; In step S3, the specific operations include: using the tracer filling device (11) to add the tracer into the source liquid pool (5); after the concentration of the tracer in the source liquid pool (5) is uniform, opening the fifth solenoid valve (13) and the sixth solenoid valve (14); using the first injection pump (15) to extract part of the source liquid; then closing the fifth solenoid valve (13) and the sixth solenoid valve (14); opening the first switching valve (16) to switch to the second waste liquid pool (18); and A portion of the source liquid in the injection pump (15) is discharged into the second waste liquid pool (18); the first switching valve (16) is then switched to the first sample bottle (17), and a portion of the source liquid in the first injection pump (15) is discharged into the first sample bottle (17); the first switching valve (16) is then switched to the second waste liquid pool (18), and the first injection pump (15) is reset; finally, the nitrogen pump (12) is used to blow out the liquid remaining in the first switching valve (16), and all valves are closed; In the step S4, the specific operations include: after the step S3 is completed, after one to five years, the tracer in the source liquid pool (5) diffuses into the sampling pool (7) through the diffusion medium (6); regularly sampling the sampling pool (7), opening the seventh solenoid valve (19) and the eighth solenoid valve (20), using the second injection pump (21) to extract part of the sample liquid in the sampling pool (7), closing the seventh solenoid valve (19) and the eighth solenoid valve (20), opening the second switching valve (22) to switch to the first The second injection pump (21) is connected to the waste liquid pool (10), and a portion of the sample liquid in the second injection pump (21) is discharged into the first waste liquid pool (10); the second switching valve (22) is then switched to the second sample bottle (23), and a portion of the sample liquid in the second injection pump (21) is discharged into the second sample bottle (23); the second switching valve (22) is then switched to the first waste liquid pool (10), and the second injection pump (21) is reset; finally, the nitrogen pump (12) is used to blow out the liquid remaining in the second switching valve (22), and all valves are closed; In the step S5, the specific operation includes: after the step S4 is completed, the nuclide is added to the source liquid pool (5) by using the dissolving device (24), and after the concentration of the nuclide in the source liquid pool (5) is uniform, the fifth solenoid valve (13) and the sixth solenoid valve (14) are opened, and part of the source liquid is extracted by using the first injection pump (15), and the fifth solenoid valve (13) and the sixth solenoid valve (14) are closed, and the first switching valve (16) is opened to switch to the second waste liquid pool (18), and the first injection pump (15) is used to inject the first solenoid valve (13) and the sixth solenoid valve (14) into the second waste liquid pool (18). A portion of the source liquid in an injection pump (15) is discharged into the second waste liquid pool (18); the first switching valve (16) is then switched to the first sample bottle (17), and a portion of the source liquid in the first injection pump (15) is discharged into the first sample bottle (17); the first switching valve (16) is then switched to the second waste liquid pool (18), so that the first injection pump (15) is reset; finally, the nitrogen pump (12) is used to blow out the liquid remaining in the first switching valve (16), and all valves are closed; In the step S6, the specific operations include: after the step S5 is completed, after five to ten years, the nuclides in the source liquid pool (5) diffuse into the sampling pool (7) through the diffusion medium (6); regularly sampling the sampling pool (7), opening the seventh solenoid valve (19) and the eighth solenoid valve (20), using the second injection pump (21) to extract part of the sample liquid in the sampling pool (7), closing the seventh solenoid valve (19) and the eighth solenoid valve (20), opening the second switching valve (22) to switch to the first waste valve (21); The method further comprises: switching the second switching valve (22) to the second sample bottle (23) to discharge a portion of the sample liquid in the second injection pump (21) into the first waste liquid pool (10); then switching the second switching valve (22) to the second sample bottle (23) to discharge a portion of the sample liquid in the second injection pump (21) into the second sample bottle (23); then switching the second switching valve (22) to the first waste liquid pool (10) to reset the second injection pump (21); and finally using the nitrogen pump (12) to blow out the liquid remaining in the second switching valve (22) and close all valves.

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