Seepage-heat transfer-chemical-stress test device for simulating high-level radioactive waste disposal and method of seepage-heat transfer-chemical-stress test device

Abstract

The invention provides a test device and method for simulating seepage, heat transfer, chemistry and stress of high-level radioactive waste disposal, the test device comprises a test box body, a rock-soil body model is arranged in the test box body, the rock-soil body model is composed of sandstone and bentonite, and a heat source is arranged in the middle of the bentonite; a fracture network is arranged in the rock-soil body model, a thermometer, a water pressure gauge and a strain gauge are placed in the fracture network and are in signal connection with a data acquisition instrument, and the data acquisition instrument is in signal connection with a data processing computer; and the test box body is also connected with a fluid supply system. Through repeated model tests, quantitative and qualitative analysis can be carried out on the influence of heat source temperature, different-configuration fracture water seepage paths, fracture water seepage speeds, fracture water chemical properties and inter-fracture water seepage interaction on a rock-soil body model temperature field, a water pressure field and a displacement field; the method has important significance for improving safe disposal of high-level radioactive waste, and is economical and practical.

Description

Technical Field

[0001] The invention belongs to the technical field of forming molds, and in particular relates to a seepage-heat transfer-chemistry-stress test device and a method for simulating high-level radioactive waste disposal. Background Art

[0002] Fractured rock masses are common in high-level radioactive waste disposal repositories, and these rock masses often constitute part of the deep geological structure. The existence of fractured rock masses has an important impact on the disposal of high-level radioactive waste. It is mainly manifested in the permeability: the permeability of fractured rock masses directly affects the flow path and speed of groundwater. In the disposal of high-level radioactive waste, the flow of groundwater may carry radioactive materials, so it is necessary to evaluate and control the permeability of fractured rock masses to reduce the risk of waste material leakage. In terms of heat conduction: fractured rock masses act as a medium for heat conduction, which affects the efficiency of heat transfer generated by waste. Radioactive waste will continue to decay and release heat. The presence of fractures may accelerate the loss of heat and may also form local high-temperature areas, affecting the stability of the surrounding environment. In terms of mechanical stability: the mechanical properties of fractured rock masses determine their stability during the waste disposal process.

[0003] During the waste placement and sealing process, as well as possible geological activities such as earthquakes, the fractured rock mass needs to have sufficient strength to withstand various stresses and prevent the destruction and collapse of the rock mass. Chemical stability: The chemical interaction between the fractured rock mass and the radioactive waste may affect the stability and isolation effect of the waste. It is necessary to evaluate the chemical reactions that may occur when the waste contacts the rock mass to ensure long-term chemical stability. In order to ensure the long-term safe isolation of high-level radioactive waste, simulation devices and experimental methods are used to study the specific role of fractured rock mass in the high-level radioactive waste disposal repository. These studies help to evaluate and predict safety issues during long-term operation and provide a scientific basis for the design and optimization of the disposal repository. Through these studies, we can better understand the interaction between seepage, heat transfer and stress, and their impact on the rock mass, thereby providing important experimental basis for the safe disposal of high-level radioactive waste. The difficulty in clarifying the safe disposal of high-level radioactive waste is to accurately grasp the influence of heat source temperature, fissure water seepage path, fissure water flow rate, fissure water chemistry, and water seepage interaction between fractures on the temperature field, stress field and displacement field of rock and soil, and to reveal the mechanism of how relevant parameters affect the safe disposal of high-level radioactive waste, which is of great significance for improving the safe disposal of high-level radioactive waste.

[0004] Based on this, a seepage-heat-transfer-chemistry-stress test device and method for simulating high-level radioactive waste disposal are proposed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a seepage-heat transfer-chemical-stress test device and method for simulating high-level radioactive waste disposal in view of the deficiencies of the above-mentioned prior art, so as to solve the problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] In a first aspect, a seepage-heat-transfer-chemical-stress test device for simulating high-level radioactive waste disposal includes a test box, a rock and soil model is arranged in the test box, the rock and soil model is composed of sandstone and bentonite, the bentonite is arranged in the middle of the sandstone, and a heat source is arranged in the middle of the bentonite;

[0008] A fracture network is provided in the rock and soil model, a thermometer, a water pressure gauge or a strain gauge is placed in the fracture network, the thermometer, the water pressure gauge and the strain gauge are respectively connected to a data acquisition instrument, and the data acquisition instrument is connected to a data processing computer;

[0009] The test box is also connected to a fluid supply system, which includes a water supply bucket and a water collection bucket. Water is pumped from the water supply bucket through a constant flow pump through a flow meter to the top of the test box, and then flows out of the test box to the water collection bucket for collection after passing through the fracture network in the rock and soil model.

[0010] As a further illustration of the present invention, the test box is made of a tempered glass plate with a thickness of 10 mm, and a steel plate with a thickness of 10 mm is arranged outside the bottom plate of the test box, and at least four universal wheels are arranged at the bottom of the test box.

[0011] As a further illustration of the present invention, 32 thermometers are arranged at the beginning of the rock and soil model, 8 thermometers are arranged at the contact surface between bentonite and sandstone outside the heat source, and a total of 40 thermometers are arranged in the rock and soil model.

[0012] As a further explanation of the present invention, the fracture network is provided with three water inlets, each of which is provided with a water pressure gauge, the fracture network is provided with four water outlets, each of which is provided with a water pressure gauge, the contact surface between bentonite and sandstone is provided with four water pressure gauges, and a total of 11 water pressure gauges are provided in the rock and soil model.

[0013] As a further illustration of the present invention, four strain gauges are arranged inside the bentonite of the rock and soil model.

[0014] As a further illustration of the present invention, the water supply barrel and the water collection barrel are both large-capacity barrels made of transparent organic plastic, and the fluid in the water supply barrel is always filled to the designed elevation.

[0015] As a further illustration of the present invention, a fine gauze with a filtering function is provided at the water outlet in the fracture network, and a faucet is provided at the water outlet outside the fracture network to control the water flow rate through the faucet.

[0016] As a further illustration of the present invention, the fracture network includes type I vertical fractures, L-shaped bent fractures, and U-shaped semi-surrounding fractures.

[0017] As a further illustration of the present invention, a 5-mm-thick metal strip is provided between the inner bentonite and the outer periphery and bottom of the sandstone inside the geotechnical model to support the fracture network through the 5-mm-thick metal strip. A 10-mm-thick metal strip is used to support the fracture network between the top of the bentonite and the sandstone. A heat-conducting metal plate is provided between the heat source and the bentonite.

[0018] In a second aspect, a method for simulating a seepage-heat transfer-chemistry-stress test device for high-level radioactive waste disposal is characterized by including the following steps:

[0019] First, confirm the normal working states of the flowmeter, thermometer, water pressure gauge, strain gauge, data acquisition instrument, and data processing computer, and then turn on the power supply of the heat source to heat the geotechnical body;

[0020] When the aperture of the type I vertical fracture in the fracture network is 5 mm, the fluid is neutral water, and the fracture water flow rate is 10 mm / s, under the conditions that the heat source temperatures are 60 °C, 80 °C, and 100 °C respectively, pump water from the water supply bucket through the flowmeter to the top inside the test box body by a constant flow pump, flow through the fracture network in the geotechnical model, then flow out of the test box body and be collected in the water collection bucket to conduct an experiment on the influence of the heat source temperature on the water temperature of the geotechnical model, the water pressure in the fracture network, and the strain of the bentonite;

[0021] When the aperture of the type I vertical fracture in the fracture network is 5 mm, the heat source temperature is 80 °C, the fluid is neutral water, and the flow rates are 4 mm / s, 6 mm / s, and 10 mm / s respectively, pump water from the water supply bucket through the flowmeter to the top inside the test box body by a constant flow pump, flow through the fracture network in the geotechnical model, then flow out of the test box body and be collected in the water collection bucket to conduct an experiment on the influence of the fracture network water flow rate on the water temperature of the geotechnical model, the water pressure in the fracture network, and the strain of the bentonite;

[0022] When the apertures of the type I vertical fracture, L-shaped bent fracture, and U-shaped semi-surrounding fracture in the fracture network are all 5 mm, the heat source temperature is 80 °C, the fracture water flow rate is 10 mm / s, and the fluid is neutral water, pump water from the water supply bucket through the flowmeter to the top inside the test box body by a constant flow pump, flow through the fracture network in the geotechnical model, then flow out of the test box body and be collected in the water collection bucket to conduct an experiment on the influence of different configurations of the fracture network on the water temperature of the geotechnical model, the water pressure in the fracture network, and the strain of the bentonite;

[0023] Under the conditions that the opening of type I vertical fractures in the fracture network is 5 mm, the heat source temperature is 80 °C, the fracture water flow rate is 10 mm / s, the fluid is an acidic aqueous solution with a pH of 4 and an alkaline aqueous solution with a pH of 10, water is pumped from the water supply barrel by a constant flow pump through a flow meter to the top of the test box, passes through the fracture network in the rock and soil model, and then flows out of the test box to the water collecting barrel for collection. The effect of the chemical properties of the fluid on the water temperature of the rock and soil model, the water pressure of the fracture network and the strain of bentonite is tested.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The present invention provides a rock and soil model in a test box, and a fracture network is provided in the rock and soil model. Through repeated model tests, the influence of heat source temperature, seepage paths of fracture water with different configurations, seepage velocity of fracture water, chemistry of fracture water, and interaction of water seepage between fractures on temperature field, water pressure field and displacement field of the rock and soil model can be obtained for quantitative and qualitative analysis, and the mechanism of the influence of relevant parameters on thermodynamic characteristics of rock mass can be revealed, which is of great significance for improving the safe disposal of high-level radioactive waste and is economical and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is an exploded view of the overall structure of the present invention.

[0027] Description of reference numerals:

[0028] 1-test box; 2-sandstone; 3-bentonite; 4-heat source; 5-thermometer; 6-water pressure gauge; 7-strain gauge; 8-water supply bucket; 9-water collection bucket; 10-data acquisition instrument; 11-data processing computer. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] like Figure 1 As shown, the present invention provides a technical solution: a seepage-heat transfer-chemical-stress test device for simulating high-level radioactive waste disposal, comprising a test box 1, the test box 1 is made of a tempered glass plate with a thickness of 10 mm, and a steel plate with a thickness of 10 mm is arranged outside the bottom plate of the test box 1 for heat insulation to prevent heat from being lost from the boundaries of the test box 1 and affecting the test reaching a steady state. At least four universal wheels are arranged at the bottom of the test box 1 for easy movement to different positions for use.

[0031] A rock and soil model is arranged in the test box 1 , and the rock and soil model is composed of sandstone 2 and bentonite 3 . The bentonite 3 is arranged in the middle of the sandstone 2 , and a heat source 4 is arranged in the middle of the bentonite 3 .

[0032] The rock and soil model is provided with a fracture network, in which a thermometer 5, a water pressure gauge 6 or a strain gauge 7 is placed for testing water temperature, water pressure and bentonite strain characteristics.

[0033] The parameters are shown in the following table:

[0034]

[0035] 32 thermometers 5 are arranged at the beginning of the rock and soil model, 8 thermometers 5 are arranged at the contact surface between the bentonite 3 and the sandstone 2 outside the heat source 4, and a total of 40 thermometers 5 are arranged in the rock and soil model.

[0036] The fracture network is provided with three water inlets, each of which is provided with a water pressure gauge 6; the fracture network is provided with four water outlets, each of which is provided with a water pressure gauge 6; four water pressure gauges 6 are provided on the contact surface between the bentonite 3 and the sandstone 2; and a total of 11 water pressure gauges 6 are provided in the rock and soil model.

[0037] Four strain gauges 7 are arranged inside the bentonite 3 of the rock and soil model.

[0038] The thermometer 5, water pressure gauge 6 and strain gauge 7 are respectively connected to the data acquisition instrument 10, and the data acquisition instrument 10 is connected to the data processing computer 11 for real-time dynamic acquisition of sensor signals in the entire test box 1. The test data can be obtained in real time using the data processing computer 11.

[0039] A fine gauze with filtering function is arranged at the water outlet in the fracture network to filter the bentonite 3 in the fluid, and a faucet is arranged at the water outlet outside the fracture network to control the water flow rate.

[0040] The crack network includes I-type vertical cracks, L-type bending cracks and U-type semi-enclosed cracks. Figure 1 In the direction indicated by the arrow.

[0041] A 5 mm thick metal strip is arranged between the bentonite 3 inside the rock and soil model and the periphery and bottom of the sandstone 2, and the fracture network is supported by the 5 mm thick metal strip. A 10 mm thick metal strip is used to support the fracture network between the top of the bentonite 3 and the sandstone 2, and a heat-conducting metal plate is arranged between the heat source 4 and the bentonite 3.

[0042] The test chamber 1 is also connected to a fluid supply system, which includes a water supply bucket 8 and a water collection bucket 9. Water is pumped from the water supply bucket by a constant flow pump through a flow meter to the top inside the test chamber 1, and after flowing through the fracture network in the geotechnical model, it flows out of the test chamber 1 and is collected in the water collection bucket 9.

[0043] Both the water supply bucket 8 and the water collection bucket 9 are large-capacity buckets made of transparent organic plastic, and the fluid in the water supply bucket 8 is always filled to the designed elevation.

[0044] The above method for simulating a seepage - heat transfer - chemistry - stress test device for high-level radioactive waste disposal includes the following steps:

[0045] First, confirm the normal working status of the flow meter, thermometer 5, water pressure gauge 6, strain gauge 7, data acquisition instrument 10, and data processing computer 11, and then turn on the power supply of the heat source 4 to heat the geotechnical body;

[0046] When the opening of the type-I vertical fracture in the fracture network is 5 mm, the fluid is neutral water, and the fracture water flow rate is 10 mm / s, under the conditions that the temperatures of the heat source 4 are 60 °C, 80 °C, and 100 °C respectively, water is pumped from the water supply bucket 8 by a constant flow pump through a flow meter to the top inside the test chamber 1, and after flowing through the fracture network in the geotechnical model, it flows out of the test chamber 1 and is collected in the water collection bucket 9 to conduct tests on the influence of the heat source temperature on the water temperature of the geotechnical model, the water pressure in the fracture network, and the strain of the bentonite 3;

[0047] When the opening of the type-I vertical fracture in the fracture network is 5 mm, the temperature of the heat source is 80 °C, the fluid is neutral water, and the flow rates are 4 mm / s, 6 mm / s, and 10 mm / s respectively, water is pumped from the water supply bucket 8 by a constant flow pump through a flow meter to the top inside the test chamber 1, and after flowing through the fracture network in the geotechnical model, it flows out of the test chamber 1 and is collected in the water collection bucket 9 to conduct tests on the influence of the fracture network water flow rate on the water temperature of the geotechnical model, the water pressure in the fracture network, and the strain of the bentonite 3;

[0048] When the openings of the type-I vertical fracture, L-shaped bent fracture, and C-shaped semi-surrounding fracture in the fracture network are 5 mm respectively, the temperature of the heat source is 80 °C, the fracture water flow rate is 10 mm / s, and the fluid is neutral water, water is pumped from the water supply bucket 8 by a constant flow pump through a flow meter to the top inside the test chamber 1, and after flowing through the fracture network in the geotechnical model, it flows out of the test chamber 1 and is collected in the water collection bucket 9 to conduct tests on the influence of different configurations of the fracture network on the water temperature of the geotechnical model, the water pressure in the fracture network, and the strain of the bentonite 3;

[0049] Under the conditions that the opening of type I vertical fractures in the fracture network is 5 mm, the heat source temperature is 80°C, the fracture water flow rate is 10 mm / s, the fluid is an acidic aqueous solution with a pH of 4 and an alkaline aqueous solution with a pH of 10, water is pumped from the water supply barrel 8 by a constant flow pump through a flow meter to the top of the test box 1, passes through the fracture network in the rock and soil model, and then flows out of the test box 1 to the water collecting barrel 9 for collection, and a test is conducted on the influence of the chemical properties of the fluid on the water temperature of the rock and soil model, the water pressure of the fracture network and the strain of bentonite 3.

[0050] After repeated model tests, we can conduct quantitative and qualitative analysis on the influence of heat source temperature, seepage paths of water in fractures of different configurations, seepage velocity of water in fractures, chemical properties of water in fractures, and water seepage interaction between fractures on the temperature field, water pressure field and displacement field of the rock and soil model, revealing the mechanism by which relevant parameters affect the thermodynamic properties of rock mass, which is of great significance for improving the safe disposal of high-level radioactive waste and is economical and practical.

[0051] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0052] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A seepage-heat-transfer-chemical-stress test device for simulating high-level radioactive waste disposal, characterized in that: The test box (1) comprises a test box (1), wherein a rock and soil model is arranged in the test box (1), wherein the rock and soil model is composed of sandstone (2) and bentonite (3), wherein the bentonite (3) is arranged in the middle of the sandstone (2), and a heat source (4) is arranged in the middle of the bentonite (3); A fracture network is provided in the rock and soil model, a thermometer (5), a water pressure gauge (6), and a strain gauge (7) are placed in the fracture network, the thermometer (5), the water pressure gauge (6), and the strain gauge (7) are respectively connected to a data acquisition instrument (10) by signal, and the data acquisition instrument (10) is connected to a data processing computer (11) by signal; The test box (1) is also connected to a fluid supply system, which includes a water supply bucket (8) and a water collection bucket (9). Water is pumped from the water supply bucket through a constant flow pump and passed through a flow meter to the top of the test box (1). After passing through the fracture network in the rock and soil model, the water flows out of the test box (1) and is collected in the water collection bucket (9).

2. The device for simulating high-level waste disposal seepage-heat transfer-chemistry-stress test according to claim 1, characterized in that: The test box (1) is made of a tempered glass plate with a thickness of 10 mm, and a steel plate with a thickness of 10 mm is arranged outside the bottom plate of the test box (1). At least four universal wheels are arranged at the bottom of the test box (1).

3. The device for simulating high-level waste disposal seepage-heat transfer-chemistry-stress test according to claim 1, characterized in that: 32 thermometers (5) are arranged at the beginning of the rock and soil model, 8 thermometers (5) are arranged at the contact surface between the bentonite (3) and the sandstone (2) outside the heat source (4), and a total of 40 thermometers (5) are arranged in the rock and soil model.

4. The device for simulating high-level waste disposal seepage-heat transfer-chemistry-stress test according to claim 1, characterized in that: The fracture network is provided with three water inlets, each of which is provided with a water pressure gauge (6); the fracture network is provided with four water outlets, each of which is provided with a water pressure gauge (6); four water pressure gauges (6) are provided on the contact surface between the bentonite (3) and the sandstone (2); and a total of 11 water pressure gauges (6) are provided in the rock and soil model.

5. The device for simulating high-level waste disposal seepage-heat transfer-chemistry-stress test according to claim 1, characterized in that: Four strain gauges (7) are arranged inside the bentonite (3) of the rock and soil model.

6. The simulated high-level waste disposal seepage-heat transfer-chemistry-stress test device according to claim 1, characterized in that: The water supply barrel (8) and the water collection barrel (9) are both large-capacity barrels made of transparent organic plastics, and the fluid in the water supply barrel (8) is always filled to the designed elevation.

7. The simulated high-level waste disposal seepage-heat transfer-chemistry-stress test device according to claim 1, characterized in that: A fine gauze with filtering function is arranged at the water outlet in the fissure network, and a faucet is arranged at the water outlet outside the fissure network, and the water flow rate is controlled by the faucet.

8. The simulated high-level waste disposal seepage-heat transfer-chemistry-stress test device according to claim 1, characterized in that: The crack network includes I-type vertical cracks, L-type bending cracks and U-type semi-enclosed cracks.

9. The device for simulating high-level waste disposal seepage-heat transfer-chemistry-stress test according to claim 1, characterized in that: A 5 mm thick metal strip is arranged between the bentonite (3) inside the rock and soil model and the outer periphery and bottom of the sandstone (2), and a fracture network is supported by the 5 mm thick metal strip. A 10 mm thick metal strip is used to support the fracture network between the top of the bentonite (3) and the sandstone (2), and a heat-conducting metal plate is arranged between the heat source (4) and the bentonite (3).

10. A method for simulating a seepage-heat-transfer-chemical-stress test device for high-level waste disposal according to any one of claims 1 to 9, characterized in that: The following steps are involved: First, confirm that the flow meter, the thermometer (5), the water pressure gauge (6), the strain gauge (7), the data acquisition instrument (10) and the data processing computer (11) are in normal working condition, and then turn on the power of the heat source (4) to heat the rock and soil mass; When the aperture of the Type-I vertical fracture in the fracture network is 5 mm, the fluid is neutral water, and the fracture water flow velocity is 10 mm / s, under the conditions that the temperatures of the heat source (4) are 60 °C, 80 °C, and 100 °C respectively, water is pumped from the water supply bucket (8) through a constant flow pump through a flowmeter to the top inside the test box (1), flows out of the test box (1) after passing through the fracture network in the geotechnical model and is collected in the water collection bucket (9), and an experiment on the influence of the heat source temperature on the water temperature of the geotechnical model, the water pressure of the fracture network, and the strain of bentonite (3) is carried out; When the aperture of the Type-I vertical fracture in the fracture network is 5 mm, the heat source temperature is 80 °C, and the fluid is neutral water, under the conditions that the flow velocities are 4 mm / s, 6 mm / s, and 10 mm / s respectively, water is pumped from the water supply bucket (8) through a constant flow pump through a flowmeter to the top inside the test box (1), flows out of the test box (1) after passing through the fracture network in the geotechnical model and is collected in the water collection bucket (9), and an experiment on the influence of the fracture network water flow velocity on the water temperature of the geotechnical model, the water pressure of the fracture network, and the strain of bentonite (3) is carried out; When the apertures of the Type-I vertical fracture, the L-shaped bent fracture, and the C-shaped semi-surrounding fracture in the fracture network are 5 mm respectively, the heat source temperature is 80 °C, the fracture water flow velocity is 10 mm / s, and the fluid is neutral water, water is pumped from the water supply bucket (8) through a constant flow pump through a flowmeter to the top inside the test box (1), flows out of the test box (1) after passing through the fracture network in the geotechnical model and is collected in the water collection bucket (9), and an experiment on the influence of fracture networks with different configurations on the water temperature of the geotechnical model, the water pressure of the fracture network, and the strain of bentonite (3) is carried out; When the aperture of the Type-I vertical fracture in the fracture network is 5 mm, the heat source temperature is 80 °C, the fracture water flow velocity is 10 mm / s, and the fluid is an acidic aqueous solution with pH = 4 and an alkaline aqueous solution with pH = 10, water is pumped from the water supply bucket (8) through a constant flow pump through a flowmeter to the top inside the test box (1), flows out of the test box (1) after passing through the fracture network in the geotechnical model and is collected in the water collection bucket (9), and an experiment on the influence of the chemical properties of the fluid on the water temperature of the geotechnical model, the water pressure of the fracture network, and the strain of bentonite (3) is carried out.

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