A hydrogen isotope permeation research device based on radio frequency plasma

Abstract

This invention discloses a hydrogen isotope permeation research device based on radio frequency plasma, belonging to the field of hydrogen isotope permeation research technology. The device includes a quartz tube, one end of which is connected to an inlet unit, and the other end has a fixed flange with a gas venting channel. A permeation tube is detachably and sealed to the fixed flange, and the inner cavity of the permeation tube is connected to a permeation flux detection unit. A tubular furnace corresponding to the permeation tube and a coupling coil electrically connected to a radio frequency generator are fitted around the quartz tube. The device also includes an in-situ reverse cleaning unit that can replace the permeation flux detection unit and a plasma diagnostic unit that can replace the permeation tube. This invention uses a radio frequency plasma source, which has high plasma density and a wide parameter adjustment range, effectively processing combined hydrogen isotopes. The in-situ reverse cleaning unit improves the permeation flux and operational stability. The modular structure provides strong engineering scalability and can support the systematic research and engineering development of ultrapermeation pumps.

Description

Technical Field

[0001] This invention relates to the field of hydrogen isotope permeation research technology, and in particular to a hydrogen isotope permeation research device based on radio frequency plasma. Background Technology

[0002] In the fields of hydrogen energy development and controlled nuclear fusion, the purification, pumping, and separation of hydrogen isotopes (protium, deuterium, and tritium) are key technological processes. Taking fusion reactors as an example, their fuel cycle systems need to efficiently process the deuterium-tritium mixture discharged from the vacuum chamber. The processing efficiency directly affects the amount of tritium stored and the scale of the entire tritium processing plant. To address this, the industry has proposed a novel processing technology based on the principle of plasma-driven superpermeation. This technology aims to achieve direct pumping and purification of deuterium-tritium gas through the high-efficiency permeation capability of metal membranes, simplifying the traditional complex purification and separation process.

[0003] Currently, plasma-driven superpermeation technology is still in the proof-of-concept and experimental research stage, and existing research mainly explores the feasibility of this technology by building experimental devices. However, the published research literature and related experimental devices have the following core shortcomings: First, plasma has a narrow operating range, poor parameter adjustment flexibility, and weak ability to handle combined hydrogen isotopes. Specifically: Existing research primarily employs heated filament ion sources as the means of plasma generation. The operating pressure of such ion sources is typically limited to an extremely low range (generally below 1 Pa), resulting in a plasma density of approximately 102. 14 ~10 16 m -3 Both the ion energy and the thermal filament ion source are low (approximately 1 eV), and the adjustable window is extremely narrow. This makes it difficult for the experimental setup to systematically study the influence of plasma characteristics on permeation performance under a wide range of operating parameters. More importantly, the energy of the thermal filament ion source is far lower than the dissociation energy of combined hydrogen such as NH3, H2O, and CH4 (generally higher than 5 eV), making it impossible to effectively extract hydrogen isotopes from these impurity gases, thus limiting the scope of research. In addition, the operating temperature control precision of the permeation material in the existing device is insufficient, and hydrides are easily formed during the cooling process, resulting in a significant decrease in the hydrogen diffusion coefficient, which cannot meet the requirements for rapid screening and performance evaluation of various candidate materials (such as palladium, niobium, tantalum, α-Fe, etc.).

[0004] Second, the device's structural engineering scalability is poor, and its feasibility for replication and scaling up is low. Specifically: Practical applications of ultraosmosis pumps require an effective permeation surface area on the order of square meters to achieve performance comparable to mainstream palladium membrane devices. However, in existing experimental setups based on thermal filament ion sources, the plasma is highly concentrated near the filament, and its density rapidly decreases with increasing distance. This spatial inhomogeneity necessitates a specially designed metal membrane that is tightly fitted to the ion source, while also integrating high-temperature heating functionality. This results in an extremely complex structure, making it difficult to scale up the effective surface area through simple array replication. This inherent structural defect prevents existing experimental setups from providing effective design and verification support for the development of engineered, large-scale ultraosmosis pumps.

[0005] In summary, existing research devices have significant shortcomings in terms of plasma source performance, parameter control flexibility, ability to handle combined hydrogen, and structural scalability. There is an urgent need to develop a novel experimental platform to support the systematic research and engineering application verification of plasma-driven superpermeation technology. Summary of the Invention

[0006] The purpose of this invention is to provide a hydrogen isotope permeation research device based on radio frequency plasma, which has a compact structure, integrated functions, can adjust plasma characteristics within a wide parameter range, effectively process combined hydrogen isotopes, and has excellent engineering expansion capabilities.

[0007] The technical solution of the present invention to solve the above-mentioned technical problems is: a hydrogen isotope permeation research device based on radio frequency plasma, including a quartz tube, one end of which is sealed to an air inlet unit, and the other end of which is sealed to a fixed flange, and the fixed flange is provided with a gas venting channel communicating with the inner cavity of the quartz tube; the fixed flange is also provided with an open end which is detachably and sealed to it, and a permeation tube which extends coaxially along the axial direction of the quartz tube into its interior, and the inner cavity of the permeation tube is connected to a permeation flux detection unit detachably and sealed to the fixed flange; The outer side of the quartz tube near the fixed flange is fitted with a tube furnace corresponding to the permeation tube, and the outer side of the quartz tube away from the fixed flange is wound with a coupling coil electrically connected to the radio frequency generator. It also includes an in-situ reverse cleaning unit for cleaning the oxide layer on the inner wall of the permeation tube, which can replace the permeation flux detection unit, and a plasma diagnostic unit that can replace the permeation tube and is coaxially inserted into the quartz tube.

[0008] As a further improvement of the present invention, the in-situ reverse cleaning unit includes a mounting flange tube that is detachably and sealed to a fixed flange via an insulating component. A cleaning electrode is provided on the mounting flange tube, which penetrates the mounting flange tube and extends into a permeation tube. The cleaning electrode is electrically connected to the anode of a high-voltage DC power supply, and the permeation tube is electrically connected to the cathode of the high-voltage DC power supply.

[0009] As a further improvement of the present invention, the cleaning electrode includes a fixed section, an intermediate pipe section and a cleaning section that are detachably connected in sequence along the axial direction. The fixed section and the intermediate pipe section are both located in the mounting flange pipe, and the cleaning section is located in the permeation pipe.

[0010] As a further improvement of the present invention, the fixed section is fitted with a fixed ceramic tube that is fixedly connected to the mounting flange tube. The fixed ceramic tube and the intermediate tube section are fitted with a detachable ceramic tube A. One end of the detachable ceramic tube A abuts against the fixed flange, and the other end abuts against one end of a spring sleeved on the fixed ceramic tube. The other end of the spring abuts against the inner wall of the mounting flange tube.

[0011] As a further improvement of the present invention, a detachable ceramic tube B is sleeved on the outer wall of the cleaning section near the fixed flange.

[0012] As a further improvement of the present invention, the insulating assembly includes an insulating plate disposed between the fixed flange and the mounting flange tube, the mounting flange tube being bolted to the fixed flange, and an insulating sleeve being fitted between the mounting flange tube and the bolt.

[0013] As a further improvement of the present invention, the air intake unit includes a deuterium gas source and an impurity gas source, both of which are sealed to a quartz tube through a pipeline equipped with a mass flow controller.

[0014] As a further improvement of the present invention, the permeation flux detection unit includes a quadrupole mass spectrometer with a multi-stage differential pumping system, wherein the quadrupole mass spectrometer is detachably and sealedly connected to a fixed flange via pipelines, connecting flanges and fixed flanges.

[0015] As a further improvement of the present invention, the coupling coil is a hollow copper tube with cooling water flowing inside, and has 2 to 3 turns; the output terminal of the radio frequency generator is electrically connected to the coupling coil via a capacitor matching device.

[0016] As a further improvement of the present invention, the gas venting channel on the fixed flange is connected to the upstream vacuum pump unit.

[0017] Beneficial effects Compared with the prior art, the advantages of the hydrogen isotope permeation research device based on radio frequency plasma of the present invention are as follows: 1. This invention uses a radio frequency generator and a coupling coil to form an inductively coupled radio frequency plasma source. Compared with the existing technology that uses a hot filament ion source, it can achieve a plasma density of 10. 16 ~10 18 m -3This technology offers a two-order-of-magnitude improvement over conventional thermal filament plasma. Radio frequency electromagnetic waves can propagate and reflect without attenuation in space, generating a large-area uniform plasma, unrestricted by space or membrane shape. Furthermore, by adjusting the radio frequency discharge power, discharge pressure, and the relative positions of the coupling coil and permeation tube, the plasma electron temperature, density, and operating temperature of the permeation material can be controlled over a wide range, enabling engineering verification of the superpermeation pump under all operating conditions and screening for optimal operating conditions. In addition, the natural ion energy of the radio frequency plasma is 10–50 eV, higher than the dissociation energy (>5 eV) of common combined hydrogen forms such as NH3, H2O, and CH4, enabling efficient stripping and extraction of hydrogen isotopes and solving the problem of weak processing capacity for combined hydrogen in existing technologies. 2. This invention specifically incorporates an in-situ reverse cleaning unit that can replace the permeation flux detection unit. Through the cooperation of the cleaning electrode and a high-voltage DC power supply, glow discharge can be excited within the permeation tube, achieving uniform cleaning of the oxide layer on the downstream inner surface of the permeation tube. This effectively removes the oxide layer's obstruction to hydrogen isotope desorption, significantly improving the permeation flux. This design also solves the problem of permeation performance degradation caused by oxide layer accumulation during long-term operation, filling the gap in existing technologies lacking in-situ reverse cleaning functionality. 3. This invention uses a tubular permeation tube as the basic permeation unit, featuring a compact structure. The permeation tube is detachably and sealed to the fixed flange, facilitating the replacement of permeation samples of different materials for performance testing. Combining the large volume and spatial divergence characteristics of radio frequency plasma, multiple permeation units can be arranged in an array to significantly increase the effective permeation surface area, thereby linearly enhancing the hydrogen isotope pumping capacity and solving the problem of replicability and scale-up in existing technologies. Furthermore, the axial installation position of the permeation tube within the quartz tube is adjustable, further enhancing the device's adaptability to different experimental scenarios. 4. This invention integrates a radio frequency plasma generation unit, a temperature control unit, a permeation flux detection unit, an in-situ reverse cleaning unit, and a plasma diagnostic unit onto a single platform. Through a replaceable design, it enables precise calibration of plasma parameters and systematic research on permeation performance. Based on the open structure of the quartz tube, it eliminates the need for complex vacuum chamber design, significantly reducing the difficulty of experimental research and engineering optimization. This provides comprehensive experimental support for the mechanism research, material screening, and operational optimization of plasma-driven superpermeation technology.

[0018] The invention will become clearer from the following description, taken in conjunction with the accompanying drawings, which are used to explain embodiments of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structural composition of the present invention; Figure 2 This is a schematic diagram of the connection structure between the permeation tube and the in-situ reverse cleaning unit of the present invention.

[0021] Wherein: 1-quartz tube; 11-fixed flange; 11a-gas venting channel; 11b-upstream vacuum pump group; 12-tube furnace; 13-coupling coil; 13a-capacitor matching device; 13b-RF generator; 2-permeation tube; 3-gas inlet unit; 31-deuterium gas source; 32-impurity gas source; 33-mass flow controller; 4-quadrupole mass spectrometer; 41-multi-stage differential pumping system; 5-cleaning electrode; 51-mounting flange tube; 52-fixed ceramic tube; 53-detachable ceramic tube A; 54-insulating sleeve; 55-insulating plate; 56-high voltage DC power supply; 57-detachable ceramic tube B. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; of course, they can also refer to a mechanical connection or an electrical connection; furthermore, they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0025] Example: Specific embodiments of the present invention are as follows: Figure 1-2As shown, a hydrogen isotope permeation research device based on radio frequency plasma is presented. The main body of the device is a quartz tube 1, made of high-purity fused quartz, with an inner diameter of 50 mm and a length of 800 mm. One end of the quartz tube 1 is sealed to an inlet unit 3, and the other end is sealed to a fixed flange 11 via a CF35 standard flange. The fixed flange 11 is provided with a gas venting channel 11a communicating with the inner cavity of the quartz tube 1. This gas venting channel 11a is connected to an upstream vacuum pump group 11b and is used to control the upstream working gas pressure inside the quartz tube 1.

[0026] A detachable, sealed permeation tube 2 is connected to the fixed flange 11. Specifically, the open end of the permeation tube 2 is sealed to the fixed flange 11, and its closed end extends coaxially along the axial direction of the quartz tube 1 into the interior of the quartz tube 1. The permeation tube 2 is made of high-purity niobium tube with an outer diameter of 20 mm and a wall thickness of 1 mm, and is 500 mm long. A niobium membrane disc with a diameter of 20 mm and a thickness of 0.5 mm is welded to its left end face. The inner cavity of the permeation tube 2 is connected to the permeation flux detection unit detachably and sealed to the fixed flange 11.

[0027] A tubular furnace 12, corresponding to the permeation tube 2, is fitted around the outside of the quartz tube 1 near the fixed flange 11. This tubular furnace 12 has a sleeve-type structure with a temperature control range of 0–1000℃ and a temperature control accuracy of ±5℃, used to precisely control the overall operating temperature of the permeation tube 2. A coupling coil 13 is wound around the outside of the quartz tube 1 away from the fixed flange 11. The coupling coil 13 is made of a hollow copper tube with an outer diameter of 6mm, wound 2–3 times with a coil spacing of 10mm. Circulating cooling water flows inside the copper tube. The coupling coil 13 is electrically connected to the radio frequency generator 13b through a capacitor matching device 13a, used to excite and form a stable inductively coupled radio frequency plasma within the quartz tube 1.

[0028] This device also includes an in-situ reverse cleaning unit that can replace the permeation flux detection unit, and a plasma diagnostic unit coaxially inserted into the quartz tube 1 that can replace the permeation tube 2. Through this replaceable design, both precise calibration of plasma parameters and systematic research on permeation performance can be achieved.

[0029] Regarding the specific structure of the in-situ reverse cleaning unit, such as... Figure 2 As shown: The in-situ reverse cleaning unit is used to clean the oxide layer on the inner wall of the permeation tube 2. It includes a mounting flange tube 51 that is detachably and sealed to a fixed flange 11 via an insulating component. A cleaning electrode 5 is provided on the mounting flange tube 51, penetrating the mounting flange tube 51 and extending into the permeation tube 2. The cleaning electrode 5 is electrically connected to the anode of a high-voltage DC power supply 56, and the permeation tube 2 is electrically connected to the cathode of the high-voltage DC power supply 56.

[0030] The cleaning electrode 5 is made of a 2mm diameter tungsten rod and includes a fixed section, an intermediate tube section, and a cleaning section that are detachably connected along the axial direction. The fixed section and the intermediate tube section are both located within the mounting flange tube 51, while the cleaning section is located within the permeation tube 2. A fixed ceramic tube 52, which is fixedly connected to the mounting flange tube 51, is sleeved over the fixed section. A detachable ceramic tube A53 is sleeved over the fixed ceramic tube 52 and the intermediate tube section. One end of the detachable ceramic tube A53 abuts against the fixed flange 11, and the other end abuts against one end of a spring sleeved on the fixed ceramic tube 52. The other end of the spring abuts against the inner wall of the mounting flange tube 51. This spring structure ensures a tight fit between the detachable ceramic tube A53 and the fixed flange 11. A detachable ceramic tube B57 is sleeved on the outer wall of the cleaning section near the fixed flange 11. In this embodiment, there are multiple detachable ceramic tubes B57, which are sequentially sleeved on the cleaning section. With the help of replaceable cleaning sections of different lengths, only the electrode section in the area to be cleaned in the corresponding permeation tube 2 is exposed, forming a symmetrical anode and cathode discharge structure, thus ensuring the accuracy of discharge cleaning.

[0031] The insulation assembly includes an insulating plate 55 disposed between the fixed flange 11 and the mounting flange tube 51. The mounting flange tube 51 is bolted to the fixed flange 11, and an insulating sleeve 54 is fitted between the mounting flange tube 51 and the bolts to achieve high-voltage insulation between the cleaning electrode 5 and the fixed flange 11 and the permeation tube 2, with an insulation withstand voltage >10kV.

[0032] Regarding the use of the in-situ reverse cleaning unit: After the high-voltage DC power supply 56 is turned on, the cleaning electrode 5 acts as the anode and the permeation tube 2 acts as the cathode, exciting a glow discharge between them. The ions generated by the discharge bombard the inner surface of the permeation tube 2, effectively removing the oxide layer formed during long-term operation through physical sputtering. The oxide layer is a major obstacle to hydrogen isotope desorption, and its presence significantly reduces the recombination rate of hydrogen atoms on the downstream surface of the permeation tube 2. Through the in-situ reverse cleaning unit, the inner surface of the permeation tube 2 can be cleaned online, restoring the cleanliness of the metal surface, thereby significantly improving the permeation flux of hydrogen isotopes and solving the problem of permeation performance degradation caused by oxide layer accumulation.

[0033] Regarding the specific structure of the intake unit, such as Figure 1 As shown, the intake unit 3 includes a deuterium gas source 31 and an impurity gas source 32. Both the deuterium gas source 31 and the impurity gas source 32 are sealed to the quartz tube 1 through pipelines equipped with mass flow controllers 33. By adjusting the two mass flow controllers 33, the concentration ratio of impurity gas to deuterium gas can be precisely controlled, allowing for the study of the impact of impurities on permeation performance. Simultaneously, by adjusting the intake rate and the pumping rate of the upstream vacuum pump group 11b, the upstream working pressure inside the quartz tube 1 can be controlled to be 1~100 Pa, matching the stable discharge requirements of radio frequency plasma.

[0034] Regarding the specific structure of the permeation flux detection unit, such as Figure 1 As shown: The permeation flux detection unit includes a quadrupole mass spectrometer 4 with a multi-stage differential pumping system 41. The quadrupole mass spectrometer 4 is detachably and sealed to the fixed flange 11 via pipelines and connecting flanges. The multi-stage differential pumping system 41 adopts a three-stage differential structure, with each stage equipped with an independent molecular pump unit, which can ensure that the vacuum degree downstream of the permeation tube 2 is maintained at 1×10⁻⁶. -5 Below Pa, it meets the high-sensitivity detection requirements of the quadrupole mass spectrometer 4, and is used to measure in real time the flux of hydrogen isotope gas permeating downstream through the permeation tube 2.

[0035] Regarding the plasma diagnostic unit, in this embodiment, a movable Langmuir electrostatic probe is used, which can replace the permeation tube 2 and be coaxially inserted into the quartz tube 1. Before the experiment, the electrostatic probe is coaxially inserted into the quartz tube 1, and the upstream vacuum pump group 11b is turned on to evacuate the vacuum level inside the quartz tube 1 to 1×10⁻⁶. -3 Below Pa, deuterium gas is introduced and the inlet and outlet rates are adjusted to control the gas pressure inside the quartz tube 1 to be 1~100 Pa; the radio frequency generator 13b is turned on and the discharge power is adjusted to 100~800W. The reflected power is reduced to the minimum through the capacitor matching device 13a to excite stable radio frequency plasma; the plasma electron temperature, electron density and space potential distribution under different discharge pressures, discharge powers and axial positions are measured by electrostatic probes to complete parameter calibration and determine the optimal installation position of the permeation tube 2.

[0036] The radio frequency generator 13b and the coupling coil 13 constitute an inductively coupled radio frequency plasma source. The radio frequency current, passing through the coupling coil 13, generates an alternating electromagnetic field within the quartz tube 1, accelerating the collision and ionization of electrons and gas molecules to form a high-density plasma. Compared to the thermal filament ion sources used in the prior art, this invention can achieve a plasma density of 10-1. 16 ~10 18 m -3 This represents a two-order-of-magnitude improvement over conventional thermal filament plasma. Radio frequency electromagnetic waves can propagate and reflect without attenuation in space, generating a large-area uniform plasma, unrestricted by space or the shape of the permeation membrane. Simultaneously, by adjusting the radio frequency discharge power, discharge pressure, and the relative positions of the coupling coil 13 and the permeation tube 2, the plasma electron temperature, density, and the working temperature of the permeation material can be controlled over a wide range. Furthermore, the natural ion energy of the radio frequency plasma is 10–50 eV, higher than the dissociation energy (>5 eV) of common combined hydrogen states such as NH3, H2O, and CH4. Hydrogen-containing ions can spontaneously dissociate on the surface of the permeation material through collisions, achieving efficient stripping and extraction of hydrogen isotopes.

[0037] The operating procedure for hydrogen permeation experiments using this device is as follows: After parameter calibration, remove the electrostatic probe and install the permeation tube 2 and the in-situ reverse cleaning unit. Evacuate the inner cavity of the permeation tube 2 to a high vacuum, turn on the tube furnace 12 to heat the permeation tube 2 to 873K, and simultaneously turn on the high voltage DC power supply 56, adjust the output voltage to 3kV, and excite glow discharge between the cleaning electrode 5 and the permeation tube 2. Continue cleaning for 30 minutes to remove the initial oxide layer formed on the inner surface of the permeation tube 2 during exposure to the atmosphere.

[0038] After cleaning, the high-voltage DC power supply 56 is turned off, the cleaning electrode 5 is removed, and the quadrupole mass spectrometer 4 is sealed to the fixed flange 11 via the connecting flange, so that the quadrupole mass spectrometer 4 is connected to the inner cavity of the permeation tube 2, maintaining a high vacuum environment downstream of the permeation tube 2. Deuterium gas is introduced into the quartz tube 1 through the mass flow controller 33, and the gas inlet and pumping rates are adjusted to control the upstream working pressure at 20 Pa. The tube furnace 12 is turned on to heat the permeation tube 2 to the set working temperature and hold it until the temperature stabilizes. The radio frequency generator 13b is turned on, and the discharge power is adjusted to 550 W. Impedance matching is achieved through the capacitor matching device 13a to excite radio frequency plasma in the quartz tube 1. The quadrupole mass spectrometer 4 records the dynamic changes of the deuterium permeation flux in real time, completing the first round of plasma-driven superpermeation performance testing.

[0039] As the number of experimental cycles increases, an oxide layer gradually accumulates on the downstream inner surface of the permeation tube 2 due to long-term exposure to a high vacuum environment or trace impurity gases, leading to a decrease in hydrogen isotope desorption efficiency and a reduction in permeation flux. When the quadrupole mass spectrometer 4 detects that the permeation flux has decreased by more than a set threshold from the initial value, an online cleaning operation is performed: First, the radio frequency generator 13b is turned off, the upstream gas inlet is stopped, and the connecting valve between the quadrupole mass spectrometer 4 and the inner cavity of the permeation tube 2 is closed; the connecting flange of the quadrupole mass spectrometer 4 is removed, and the mounting flange tube 51 of the in-situ reverse cleaning unit is sealed to the fixed flange 11 through an insulating component, so that the cleaning electrode 5 is coaxially inserted into the inner cavity of the permeation tube 2; the high-voltage DC power supply 56 is turned on, the output voltage is adjusted to 3kV, and glow discharge is excited between the cleaning electrode 5 and the permeation tube 2, and cleaning is continued for 15~30 minutes to remove the accumulated oxide layer through ion sputtering; after cleaning is completed, the high-voltage DC power supply 56 is turned off, the in-situ reverse cleaning unit is removed, and the quadrupole mass spectrometer 4 is reconnected.

[0040] After online cleaning was completed, experimental conditions were restored, and the permeation flux was measured again. The permeation flux recovered to the initial level after cleaning, verifying the regeneration effect of the in-situ reverse cleaning unit on permeation performance.

[0041] The aforementioned cycle of "permeation experiment - performance degradation - online cleaning - performance recovery - continued experiment" can be repeated multiple times as needed to achieve long-term service performance evaluation of the same permeation tube 2. By recording the changes in permeation flux before and after each cleaning cycle, the evolution of the surface microstructure of the permeation material in a plasma environment and its correlation mechanism with permeation performance can be systematically studied.

[0042] After all experiments are completed, the in-situ reverse cleaning unit can be connected again to perform a final cleaning of the inner surface of the permeation tube 2, which facilitates the disassembly and storage of the permeation tube 2 or subsequent characterization and analysis.

[0043] In this embodiment, a tubular permeation tube 2 is used as the basic permeation unit, which has a compact structure. The permeation tube 2 is detachably and sealed to the fixed flange 11, facilitating the replacement of permeation samples of different materials, such as palladium, niobium, tantalum, and α-Fe, for performance testing. Combining the large volume and spatial divergence characteristics of radio frequency plasma, the effective permeation surface area can be multiplied by arranging multiple permeation units in an array, thereby linearly improving the hydrogen isotope pumping capacity. At the same time, the axial installation position of the permeation tube 2 inside the quartz tube 1 is adjustable. By adjusting the relative distance between the permeation tube 2 and the coupling coil 13, the plasma parameters at the permeation working surface can be controlled, further enhancing the adaptability of the device to different experimental scenarios.

[0044] It is important to note that: This device performs permeation performance tests under different operating conditions by adjusting the radio frequency discharge power, upstream discharge pressure, permeation tube operating temperature, and impurity gas concentration. It obtains the influence of each parameter on the permeation flux and selects the optimal operating conditions. This invention integrates a radio frequency plasma generation unit, a temperature control unit, a permeation flux detection unit, an in-situ reverse cleaning unit, and a plasma diagnostic unit onto a single platform. Through a replaceable design, it enables precise calibration of plasma parameters and systematic research on permeation performance, providing comprehensive experimental support for the mechanism research, material screening, and operating condition optimization of plasma-driven superpermeation technology.

[0045] Meanwhile, based on the structure of this device, a prototype of an array-type ultrapermeability pump can be developed. Its specific structure is as follows: seven sets of tubular permeation units, as described in this embodiment, are arranged coaxially in a ring array within the same quartz discharge cavity, sharing a single set of radio frequency plasma generation unit, gas inlet unit, and temperature control unit. Radio frequency coupling coils are wound along the axial direction of the quartz discharge cavity to generate a large-volume, uniform radio frequency plasma, fully covering the permeation working surface of all permeation units. Each permeation unit has an independently set in-situ cleaning unit and flux detection unit downstream; alternatively, the downstream of all permeation units can be connected to a unified purified gas collection system. This embodiment, through array-based expansion, increases the effective permeation surface area to seven times that of a single tube, achieving a linear increase in hydrogen isotope pumping capacity, thus verifying the feasibility of the engineering scale-up of this invention.

[0046] The present invention has been described above in conjunction with the preferred embodiments, but the present invention is not limited to the embodiments disclosed above, but should cover various modifications and equivalent combinations made in accordance with the essence of the present invention.

Claims

1. A hydrogen isotope permeation research device based on radio frequency plasma, characterized in that, The system includes a quartz tube (1), one end of which is sealed to an air inlet unit (3), and the other end is sealed to a fixed flange (11). The fixed flange (11) is provided with a gas venting channel (11a) that communicates with the inner cavity of the quartz tube (1). The fixed flange (11) is also provided with an open end that is detachably sealed to it, and a closed end that extends coaxially along the axial direction of the quartz tube (1) to its interior, and the inner cavity of the permeation tube (2) is connected to a permeation flux detection unit that is detachably sealed to the fixed flange (11). The quartz tube (1) is fitted with a tube furnace (12) corresponding to the permeation tube (2) on the side of the quartz tube (1) close to the fixed flange (11), and a coupling coil (13) electrically connected to the radio frequency generator (13b) is wound around the side of the quartz tube (1) away from the fixed flange (11). It also includes an in-situ reverse cleaning unit for cleaning the oxide layer on the inner wall of the permeation tube (2) that can replace the permeation flux detection unit, and a plasma diagnostic unit that can replace the permeation tube (2) and is coaxially inserted into the quartz tube (1).

2. The hydrogen isotope permeation research device based on radio frequency plasma according to claim 1, characterized in that, The in-situ reverse cleaning unit includes a mounting flange tube (51) that is detachably and sealed to a fixed flange (11) via an insulating component. A cleaning electrode (5) is provided on the mounting flange tube (51) and extends through the mounting flange tube (51) into the permeation tube (2). The cleaning electrode (5) is electrically connected to the anode of a high-voltage DC power supply (56), and the permeation tube (2) is electrically connected to the cathode of the high-voltage DC power supply (56).

3. The hydrogen isotope permeation research device based on radio frequency plasma according to claim 2, characterized in that, The cleaning electrode (5) includes a fixed section, an intermediate pipe section and a cleaning section that are detachably connected in sequence along the axial direction. The fixed section and the intermediate pipe section are both located in the mounting flange pipe (51), and the cleaning section is located in the permeation pipe (2).

4. The hydrogen isotope permeation research device based on radio frequency plasma according to claim 3, characterized in that, The fixed section is fitted with a fixed ceramic tube (52) that is fixedly connected to the mounting flange tube (51). The fixed ceramic tube (52) and the intermediate tube section are fitted with a detachable ceramic tube A (53). One end of the detachable ceramic tube A (53) abuts against the fixed flange (11), and the other end abuts against one end of a spring sleeved on the fixed ceramic tube (52). The other end of the spring abuts against the inner wall of the mounting flange tube (51).

5. The hydrogen isotope permeation research device based on radio frequency plasma according to claim 4, characterized in that, A detachable ceramic tube B (57) is sleeved on the outer wall of the cleaning section near the fixed flange (11).

6. The hydrogen isotope permeation research apparatus based on radio frequency plasma according to any one of claims 2-5, characterized in that, The insulation assembly includes an insulation plate (55) disposed between the fixed flange (11) and the mounting flange tube (51), the mounting flange tube (51) being bolted to the fixed flange (11), and an insulation sleeve (54) being fitted between the mounting flange tube (51) and the bolt.

7. The hydrogen isotope permeation research device based on radio frequency plasma according to claim 1, characterized in that, The air intake unit (3) includes a deuterium gas source (31) and an impurity gas source (32), both of which are sealed to the quartz tube (1) through a pipeline with a mass flow controller (33).

8. The hydrogen isotope permeation research device based on radio frequency plasma according to claim 1, characterized in that, The permeation flux detection unit includes a quadrupole mass spectrometer (4) with a multi-stage differential pumping system (41), which is detachably and sealed to a fixed flange (11) via pipelines, connecting flanges and fixed flanges (11).

9. The hydrogen isotope permeation research device based on radio frequency plasma according to claim 1, characterized in that, The coupling coil (13) is a hollow copper tube with cooling water flowing inside, and has 2 to 3 turns; the output terminal of the radio frequency generator (13b) is electrically connected to the coupling coil (13) via a capacitor matching device (13a).

10. The hydrogen isotope permeation research device based on radio frequency plasma according to claim 1, characterized in that, The gas venting channel (11a) on the fixed flange (11) is connected to the upstream vacuum pump unit (11b).

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