A system and process for separating tritium and its isotopes

Abstract

The application provides a system and a process for separating tritium and isotopes thereof, and relates to the technical field of hydrogen isotope separation and purification. The system comprises sequentially connected gas inlet pipeline, separation pipeline, detection pipeline, product pipeline, tail gas pipeline and recovery pipeline; the separation pipeline is sequentially connected with a first booster pump, a buffer tank, a separator and a condenser; the separator comprises a shell, a cooling medium circulating machine, a cooling medium and a spiral pipe; the spiral pipe is located in the shell; the detection pipeline is provided with a mass spectrometer; the outlet end of the detection pipeline is connected with the product pipeline and the tail gas pipeline; and the recovery pipeline is connected with the tail gas pipeline and the inlet end of the first booster pump. The process is as follows: the mixed gas is collected in the low-temperature spiral pipe by using the difference in migration rate of hydrogen and isotope components, qualified gas enters a product tank, and unqualified gas is recycled and separated through the recovery pipeline. The application does not need to fill expensive materials and does not need external carrier gas, and has the advantages of simple system structure, good safety and high tritium recovery rate.

Description

Technical Field

[0001] This invention relates to the field of hydrogen isotope separation and purification technology, and more specifically, to a system and process for separating tritium and its isotopes. Background Technology

[0002] The separation of hydrogen isotopes (protium, deuterium, and tritium) has significant application value in nuclear energy utilization fields such as nuclear fusion fuel cycle and tritium-containing exhaust gas treatment in heavy water reactors. Currently, hydrogen isotope separation mainly employs technical routes such as cryogenic distillation, cryogenic displacement chromatography, thermal cycling adsorption, and membrane separation.

[0003] The separation mechanisms of the aforementioned existing technologies all rely on differences in thermodynamic equilibrium or adsorption selectivity. Cryogenic distillation utilizes the minute differences in boiling points between different hydrogen isotope molecules to achieve separation, requiring extremely low distillation temperatures (approximately 20 K) and a large number of theoretical plates. Cryogenic displacement chromatography and thermal cycling adsorption methods both rely on differences in the adsorption capacity of packed materials (such as palladium-loaded alumina, metallic palladium, etc.) for hydrogen isotopes, requiring carrier gas displacement or temperature cycling. These mechanisms dictate that existing technologies inevitably rely on external cryogenic media (liquid helium / liquid nitrogen), external carrier gases (helium), or expensive packed materials, leading to complex system structures, high energy consumption, and problems such as radioactive contamination and reduced recovery rates due to tritium retention. Therefore, they suffer from system complexity, resource dependence, and operating costs. Furthermore, in existing technologies, cryogenic displacement chromatography and TCAP typically employ continuous or semi-continuous feeding methods, making it difficult to reprocess residual tritium in the tail gas within the same system, thus limiting tritium recovery rates. There is currently a lack of a process solution that can gradually and completely separate the tritium component within a single system through a closed-loop circulation for the generation of large quantities of tritium-containing waste gas in a single operation.

[0004] Therefore, there is an urgent need in the field for a tritium and its isotope separation system and process based on different separation mechanisms, which does not rely on external cold sources and carrier gases, does not require expensive filling materials, and has good safety. Summary of the Invention

[0005] The purpose of this invention is to provide a system for separating tritium and its isotopes, which can maintain effective separation capability while significantly reducing system complexity, resource dependence and operating costs.

[0006] Another object of the present invention is to provide a method for separating tritium and its isotopes, which can effectively separate tritium components from hydrogen isotope mixtures without the need for expensive filling materials and external carrier gas, greatly simplifying the separation process and saving costs.

[0007] The embodiments of the present invention are implemented as follows: In a first aspect, embodiments of this application provide a system for separating tritium and its isotopes, including an inlet pipe, a separation pipe, a detection pipe, a product pipe, an exhaust pipe, and a recovery pipe; The inlet end of the separation pipeline is connected to the outlet end of the air inlet pipeline, and the outlet end of the separation pipeline is connected to the inlet end of the detection pipeline. A first booster pump, a buffer tank, a separator, and a condenser are connected in series along the gas flow direction on the separation pipeline. The separator includes a housing, a cooling medium circulator, a cooling medium, and a spiral tube connected in series in the separation pipeline. The spiral tube is located inside the housing, and the cooling medium fills the space between the housing and the spiral tube. The inlet and outlet of the cooling medium circulator are both connected to the interior of the housing. A mass spectrometer is installed on the detection pipeline to monitor whether the gas in the detection pipeline is up to standard; The outlet end of the detection pipeline is connected to the inlet end of the product pipeline and the inlet end of the exhaust gas pipeline, respectively. The product pipeline is connected to a product tank at its outlet end, and a sixteenth control valve is connected in series on the product pipeline. The fourteenth control valve and the tail gas tank are connected in series along the gas flow direction on the tail gas pipeline. The inlet end of the recovery pipeline is connected to the outlet end of the exhaust gas pipeline, and the outlet end of the recovery pipeline is connected to the inlet end of the first booster pump. An eighteenth control valve is connected in series on the recovery pipeline.

[0008] In some embodiments of the present invention, the inlet end of the above-mentioned air intake pipe is connected to a mixed gas container, and a first control valve and a fifth control valve are sequentially arranged between the mixed gas container and the first booster pump. The first control valve is connected in series in the air intake pipe, and the fifth control valve is connected in series in the separation pipe. A vacuum pump is connected in parallel to the fifth control valve, and a second control valve and a third control valve are connected in series on the inlet side and the outlet side of the vacuum pump, respectively. A seventh control valve is provided at the outlet end of the first booster pump, and a sixth control valve is connected in parallel between the outlet end of the seventh control valve and the inlet end of the first booster pump.

[0009] In some embodiments of the present invention, the outlet end of the vacuum pump is also connected to an exhaust pipe, a fourth control valve is connected in series on the exhaust pipe, and the connection point of the exhaust pipe is located between the third control valve and the vacuum pump.

[0010] In some embodiments of the present invention, the outlet end of the above-mentioned recovery pipeline is connected between the vacuum pump and the second control valve.

[0011] In some embodiments of the present invention, a twelfth control valve, a second booster pump, and a thirteenth control valve are connected in series along the gas flow direction on the detection pipeline between the mass spectrometer and the condenser.

[0012] In some embodiments of the present invention, an eleventh control valve is connected in parallel between the inlet end of the twelfth control valve and the outlet end of the thirteenth control valve.

[0013] In some embodiments of the present invention, the outer shell is a sandwich structure, the sandwich structure is vacuum-treated, and the sandwich structure is filled with perlite material.

[0014] In some embodiments of the present invention, the buffer tank, product tank and exhaust gas tank are all sandwich tank structures, and the sandwich of the sandwich tank structure is vacuumed.

[0015] Secondly, embodiments of this application provide a process for separating tritium and its isotopes, employing the aforementioned system, and including the following steps: S1: The mixed gas is sent into the separation pipeline through the intake pipeline, and after being pressurized by the first booster pump, it is sent into the buffer tank; S2: The mixed gas in the buffer tank enters the separator. The cooling medium circulation machine cools the mixed gas in the spiral tube through the cooling medium, so that the different components in the mixed gas are distributed sequentially in the low temperature spiral tube due to the difference in migration rate. Among them, the tritium component flows out later than other components because of its longer adsorption retention time. The outlet end forms a time series distribution of tritium-depleted in the front section and tritium-rich in the back section. S3: After the gas flowing out of the separator enters the condenser and is restored to the predetermined temperature, it enters the detection pipeline, where the mass spectrometer detects in real time whether the tritium concentration in the gas is within the acceptable range. S4: Stream split control based on mass spectrometer detection results: If the tritium concentration is within acceptable limits, the gas will be sent into the product tank through the product pipeline. If the tritium concentration is not up to standard, the gas will be sent into the exhaust gas tank through the exhaust gas pipeline. S5: After the separator completes one separation, the unqualified gas in the tail gas tank is drawn back to the inlet end of the first booster pump through the recovery pipeline. After being pressurized by the first booster pump, it is sent back into the buffer tank. Steps S2 to S4 are repeated for cyclic separation. S6: Repeat step S5 until the mass spectrometer can no longer detect a qualified tritium concentration gas, then stop the process.

[0016] In some embodiments of the present invention, in step S2 above, the cooling medium circulator cools the mixed gas in the spiral tube to -100°C to -90°C.

[0017] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: 1. In this invention, the mixed gas, upon entering the spiral tube, exchanges heat with the external cooling medium, rapidly cooling to a predetermined temperature range. Within this low-temperature range, under the combined effects of quantum sieving, Dean's vortex, and wall collision, the migration rates of different hydrogen isotope molecules differ in the hollow spiral channel. The tritium-containing component, due to its longer adsorption retention time, flows out later than other components, resulting in a time-series distribution at the outlet: a tritium-depleted section at the front and a tritium-rich section at the back. Therefore, the tritium-rich gas in the back section more easily meets the requirements for qualified gas. After mass spectrometry detection, the qualified tritium concentration gas is sent to the product tank for storage. Compared to existing technologies, this invention has a simpler structure, requires no expensive internal filling materials, and eliminates the need for trays or packing support structures, effectively saving costs. Furthermore, this invention requires no external carrier gas, further reducing operating costs and system complexity.

[0018] 2. The invention includes a tail gas pipeline and a recovery pipeline. After one separation, the separated mixed gas can be circulated back to the separation pipeline through the tail gas pipeline and the recovery pipeline for a second separation. This allows for multiple separations. In existing technologies, the tritium remaining in the tail gas after a single separation is often difficult to recover. This invention uses a mass spectrometer for real-time online detection and automatic flow separation. The tritium-poor, substandard gas flowing out in the initial separation stage is fully circulated back to the booster pump inlet through the recovery pipeline, allowing the mixed gas to re-enter the separation pipeline for further separation. The tritium-rich, qualified gas flowing out in the later stages of separation is sent to the product tank for collection until the mass spectrometer can no longer detect a qualified tritium concentration. This achieves maximum tritium recovery from the same batch of mixed gas, avoiding resource waste and emission risks, and reducing material costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is an embodiment of the present invention. Figure 1 Enlarged schematic diagram of the intermediate vacuum pump; Figure 3 This is an embodiment of the present invention. Figure 1 Enlarged schematic diagram of the separation pipeline in the middle; Figure 4 This is an embodiment of the present invention. Figure 1An enlarged schematic diagram of the detection pipeline.

[0021] Icons: 1-Intake line; 2-Separation line; 3-Detection line; 4-Product line; 5-Exhaust gas line; 6-Recovery line; 7-First booster pump; 8-Buffer tank; 9-Separator; 901-Outer casing; 902-Cooling medium circulator; 903-Cooling medium; 10-Exhaust gas tank; 11-Helical tube; 12-Condenser; 13-Mass spectrometer; 14-Product tank; 15-Second booster pump; 16-Mixed gas container; 17-Vacuum pump; 18-Exhaust line; 19-Perlite material; 20-First control valve; 21-Second control valve; 22-Third control valve; 23-Fourth control valve; 24-Fifth control valve; 25-Sixth control valve; 26 - Seventh control valve; 27- Eighth control valve; 28- Ninth control valve; 29- Tenth control valve; 30- Eleventh control valve; 31- Twelfth control valve; 32- Thirteenth control valve; 33- Fourteenth control valve; 34- Fifteenth control valve; 35- Sixteenth control valve; 36- Seventeenth control valve; 37- Eighteenth control valve; 38- Shut-off valve; 39- Second pressure sensor; 40- Third pressure sensor; 41- Fourth pressure sensor; 42- Fifth pressure sensor; 43- Sixth pressure sensor; 44- Seventh pressure sensor; 45- Eighth pressure sensor; 46- First drain pipe; 47- Second drain pipe; 48- Flow controller. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0024] Example 1 Please refer to Figures 1-4This embodiment provides a system for separating tritium and its isotopes, including an inlet pipe 1, a separation pipe 2, a detection pipe 3, a product pipe 4, an exhaust pipe 5, and a recovery pipe 6. The inlet end of the separation pipe 2 is connected to the outlet end of the inlet pipe 1, and the outlet end of the separation pipe 2 is connected to the inlet end of the detection pipe 3. A first booster pump 7, a buffer tank 8, a separator 9, and a condenser 12 are connected in series along the gas flow direction on the separation pipe 2. The separator 9 includes a housing 901, a cooling medium circulator 902, a cooling medium 903, and a spiral tube 11 connected in series on the separation pipe 2. The spiral tube 11 is located inside the housing 901, and the cooling medium 903 fills the space between the housing 901 and the spiral tube 11. The inlet and outlet of the cooling medium circulator 902 are both connected to the interior of the housing 901. A mass spectrometer 13 is installed on the detection pipe 3 to monitor whether the gas in the detection pipe 3 is qualified. The outlet of detection pipeline 3 is connected to the inlet of product pipeline 4 and the inlet of exhaust gas pipeline 5, respectively. The outlet of product pipeline 4 is connected to product tank 14, and a sixteenth control valve 35 is connected in series on product pipeline 4. A fourteenth control valve 33 and exhaust gas tank 10 are connected in series along the gas flow direction on exhaust gas pipeline 5. The inlet of recovery pipeline 6 is connected to the outlet of exhaust gas pipeline 5, and the outlet of recovery pipeline 6 is connected to the inlet side of the first booster pump 7. An eighteenth control valve 37 is connected in series on recovery pipeline 6.

[0025] During operation, a tritium-hydrogen isotope mixture is introduced into the separation line 2 via inlet line 1. The booster pump is then activated, pressurizing the mixture before it is fed into buffer tank 8 for buffering, and gas mass balance is performed. For extremely low partial pressure gases (such as rare tritium gases with extremely low tritium content), the booster pump and vacuum pump 17 are used in series. The vacuum pump 17 establishes negative pressure at the front end for intake, while the booster pump pressurizes and discharges the gases at the rear end, effectively collecting and pressurizing the extremely low partial pressure tritium and its isotope gases into buffer tank 8 to achieve pressure conditions suitable for subsequent separation operations.

[0026] Subsequently, the mixed gas in the buffer tank 8 is introduced into the separator 9 at a set flow rate. The separator 9 has an internal spiral tube 11 structure, which is immersed in the cooling medium 903 within the outer shell 901. The cooling medium circulator 902 drives the cooling medium 903 to circulate between the outer shell 901 and the spiral tube 11, exchanging heat with the gas inside the tube through the tube wall, thus cooling the mixed gas inside the tube to a predetermined low temperature. Under low-temperature conditions, due to the combined effects of quantum sieving, Dean's vortex, and wall collision, the migration rates of different hydrogen isotope molecules differ in the empty spiral channel when the mixed gas passes through the spiral tube 11. Among them, the heavy isotope (tritium) has a lower zero-point energy and stronger adsorption to the tube wall, resulting in a longer residence time near the tube wall. Therefore, the migration rate of the tritium-containing component is slower than that of other components, and the tritium component flows out later than other components, forming a time-series distribution of "tritium-depleted at the front and tritium-rich at the back" at the outlet. The low-temperature gas flowing out of separator 9 then enters condenser 12, where heat exchange restores the gas to a predetermined temperature (e.g., 20°C to 30°C), bringing it to the conditions required for normal operation of mass spectrometer 13. The rewarmed gas then enters detection line 3, where mass spectrometer 13 performs real-time online sampling and analysis, detecting the tritium concentration and outputting a detection signal. Based on the real-time detection results from mass spectrometer 13, the control system automatically controls the gas flow direction. When the tritium concentration is detected to be below the acceptable standard, the fourteenth control valve 33 is opened and the sixteenth control valve 35 is closed. The substandard gas enters the tail gas tank 10 for temporary storage through the tail gas pipeline 5. The substandard gas corresponds to the lean tritium gas that flows out in the initial stage of separation.

[0027] When the tritium concentration reaches the acceptable standard (e.g., 90% to 99%), the sixteenth control valve 35 is opened and the fourteenth control valve 33 is closed. The qualified gas enters the product tank 14 for storage through the product pipeline 4. Since the tritium component flows out later than other components, the qualified gas corresponds to the tritium-rich gas flowing out in the later stage of separation.

[0028] Finally, after separation is completed in separation pipeline 2, the eighteenth control valve 37 is opened, and the substandard gas (tritium-deficient gas) in the tail gas tank 10 is re-pumped into the buffer tank 8 via the first booster pump 7, and the above separation steps are repeated. This cycle is repeated until the mass spectrometer 13 can no longer detect qualified tritium concentration gas, at which point the operation stops. After multiple cycles, the tritium-rich gas flowing out in the later stage of separation is gradually collected in the product tank 14, and the tritium-deficient gas is continuously refluxed and separated again. Finally, the tritium component in the mixed gas is gradually separated and enriched in the product tank 14, realizing the separation of tritium and its isotopes from other hydrogen isotope components.

[0029] Existing separation mechanisms are based on differences in thermodynamic equilibrium (e.g., low-temperature distillation utilizing boiling point differences) or differences in adsorption selectivity (e.g., chromatography / TCAP utilizing the different adsorption capacities of packed materials for isotopes). However, the core separation mechanism of this embodiment is based on differences in kinetic migration rates. Specifically, this embodiment is based on the following physical principles: 1. At sufficiently low temperatures (typically <100K), the diffusion behavior of hydrogen isotope molecules in confined spaces exhibits a "quantum sieving" phenomenon. Classical theory predicts that lighter isotopes diffuse faster than heavier isotopes. However, under low-temperature quantum sieving conditions, due to the dominance of the zero-point energy effect, the adsorption of heavy isotopes (tritium) onto the tube wall is stronger, resulting in a longer residence time near the tube wall. Therefore, the migration rate of heavy isotopes is slower than that of lighter isotopes. Specifically, tritium (T2) has a lower zero-point energy than protium (H2) and deuterium (D2), resulting in stronger van der Waals forces with the tube wall material. At low temperatures, it is more likely to be "captured" and retained by the tube wall, thus taking longer to pass through the spiral tube and escaping later than other components. Therefore, in low-temperature spiral tubes, the tritium component lags behind other components in escaping, forming a time-series distribution at the outlet end that is tritium-depleted at the beginning and tritium-rich at the end.

[0030] 2. When gas flows in the helical tube 11, it generates Dean vortices (secondary flow). Isotope molecules of different molecular weights / masses exhibit different migration behaviors in the secondary flow. The radius of curvature, pitch, and diameter of the helical tube 11 jointly determine the intensity and distribution of the Dean vortices, thereby affecting the axial migration rate distribution of molecules of different masses and zero-point energies.

[0031] 3. Under low-temperature conditions (-100℃ to -90℃), the mean free path of gas molecules decreases, the collision frequency between molecules and the tube wall increases, and the differences in van der Waals forces and scattering angles between the wall and molecules of different masses are amplified. Due to its stronger interaction with the tube wall, the heavy isotope (tritium) has a significantly longer residence time near the tube wall than the light isotopes (protium and deuterium), further enhancing its delayed outflow at the outlet.

[0032] The combined effect of these three factors results in a slower migration rate for tritium-containing components compared to other hydrogen isotope components in the cryogenic air-tube spiral flow channel. This leads to a sequential distribution at the outlet, with the initial section consisting of tritium-poor gas (dominated by protium and deuterium) and the subsequent section consisting of tritium-rich gas (dominated by tritium). This forms the physical basis of the entire separation scheme.

[0033] In summary, after the mixed gas enters the spiral tube 11 in this embodiment, it exchanges heat with the external cooling medium 903, thereby rapidly cooling to the predetermined temperature range. Within this low-temperature range, due to the combined effects of quantum sieving, Dean's vortex, and wall collision, the migration rates of different hydrogen isotope molecules differ in the hollow spiral channel. The tritium-containing component, due to its longer adsorption and retention time, migrates more slowly than other components, thus exiting the spiral tube 11 later than the others, forming a time-series distribution at the outlet end that is tritium-depleted at the front and tritium-rich at the back. Therefore, the tritium-rich gas in the back section more easily meets the requirements for qualified gas. After detection by the mass spectrometer 13, the qualified tritium concentration gas is sent to the product tank 14 for storage. Compared to existing technologies, this embodiment has a simpler structure, no expensive internal filling materials, and no need for trays or packing support structures, effectively saving costs. Furthermore, this invention does not require any external carrier gas, further reducing operating costs and system complexity.

[0034] Meanwhile, in this embodiment, the exhaust gas pipeline 5 and recovery pipeline 6, after completing one separation, can circulate the tritium-deficient gas flowing out from the first stage back to the separation pipeline 2 for secondary separation. This allows for multiple separations. In existing technologies, the tritium remaining in the exhaust gas after a single separation is often difficult to recover. In this embodiment, the mass spectrometer 13 detects in real time and automatically splits the gas, recirculating the substandard gas (tritium-deficient gas) back to the booster pump inlet through the recovery pipeline 6, allowing the mixed gas to re-enter the separation pipeline 2 for separation. The tritium-rich qualified gas flowing out from the second stage is sent to the product tank 14 for collection until the mass spectrometer 13 can no longer detect qualified tritium concentration gas. This achieves maximum tritium recovery from the same batch of mixed gas, avoiding resource waste and emission risks, and also reducing material costs.

[0035] Furthermore, existing cryogenic distillation technologies require distillation columns, reboilers, condensers 12, and numerous theoretical trays of internal components, resulting in complex structures and high precision requirements for manufacturing. Cryogenic displacement chromatography and TCAP technologies require packed separation columns and carrier gas supply / purification systems. This embodiment uses a spiral tube 11 as the core separation element of the separator 9. It contains no expensive packing material, eliminates the need for trays or packing support structures, and has its own built-in cooling medium circulator 902, eliminating the need for external cryogenic medium supply facilities. The overall system structure is compact, significantly reducing equipment investment and floor space.

[0036] Existing cryogenic distillation methods rely on external cryogenic media such as liquid helium (approximately 20K) or liquid nitrogen (approximately 77K). Cryogenic displacement chromatography also requires liquid nitrogen as an external cold source and helium as a carrier gas. This not only results in extremely high energy consumption but also severe constraints on the supply conditions of cryogenic media and carrier gases, leading to high operating costs. This embodiment utilizes a built-in cooling medium circulator 902, requiring only electrical power to directly cool the gas within the spiral tube 11 to -100℃ to -90℃ via the circulation of cooling medium 903, eliminating the need for any external cold sources such as liquid helium or liquid nitrogen. Simultaneously, a booster pump and a vacuum pump 17, connected in series, provide gas driving force, and, in conjunction with the recovery pipeline 6, allow for the direct recirculation and back-drawing of substandard gases, eliminating the need for any external carrier gases such as helium. The system is completely self-sufficient, significantly reducing energy consumption and eliminating limitations imposed by external resource supply. Furthermore, the built-in cooling circulator allows the entire system to operate completely independently, avoiding the expansion of pollution leaks caused by using external cooling circulation equipment.

[0037] Furthermore, the inlet end of the aforementioned intake pipe 1 is connected to a mixed gas container 16. A first control valve 20 and a fifth control valve 24 are sequentially arranged between the mixed gas container 16 and the first booster pump 7. The first control valve 20 is connected in series on the intake pipe 1, and the fifth control valve 24 is connected in series on the separation pipe 2. A vacuum pump 17 is connected in parallel to the fifth control valve 24. A second control valve 21 and a third control valve 22 are connected in series on the inlet and outlet sides of the vacuum pump 17, respectively. A seventh control valve 26 is provided at the outlet end of the first booster pump 7, and a sixth control valve 25 is connected in parallel between the outlet end of the seventh control valve 26 and the inlet end of the first booster pump 7.

[0038] Furthermore, in this embodiment, the outlet end of the vacuum pump 17 is also connected to an exhaust pipe 18, and a fourth control valve 23 is connected in series on the exhaust pipe 18. The connection point of the exhaust pipe 18 is located between the third control valve 22 and the vacuum pump 17.

[0039] Furthermore, in this embodiment, the outlet end of the aforementioned recovery pipeline 6 is connected between the vacuum pump 17 and the second control valve 21.

[0040] In this embodiment, the vacuum pump 17 mainly serves two functions: The first function is to evacuate the entire system's piping and components, maintaining a negative pressure throughout the system. The purpose of this step is twofold: first, to remove residual air and impurities from the system, establishing a clean environment to prevent impurities from interfering with the separation effect; and second, to maintain negative pressure while the system is shut down, ensuring that even in the event of a minor leak, outside air will be drawn in, preventing the escape of radioactive tritium-containing gas. Specifically, during the evacuation process, the second control valve 21, the fifth control valve 24, the sixth control valve 25, the seventh control valve 26, the eleventh control valve 30, the twelfth control valve 31, the thirteenth control valve 32, the fourteenth control valve 33, the sixteenth control valve 35, and the eighteenth control valve 37 are opened, while the remaining control valves are closed. At this time, the vacuum pump 17 extracts the residual gas from the entire system along the exhaust pipe 18. In this process, the pipe containing the sixth control valve 25 is actually used to allow the vacuum pump 17 to extract the gas from both sides of the first booster pump 7; similarly, the opening of the eleventh control valve 30 facilitates the extraction of gas from both sides of the second booster pump 15.

[0041] The second function is to achieve pressurized collection of low-partial-pressure tritium-containing gas. Vacuum pump 17 acts as a pre-stage, providing low-pressure suction to draw tritium-containing gas with extremely low partial pressure from the gas source; first booster pump 7 acts as a post-stage, providing pressurized discharge to compress the gas and send it into the buffer tank. For example, during normal operation, opening the first control valve 20, the fifth control valve 24, and the seventh control valve 26, and starting the first booster pump 7, can draw the mixed gas in the mixed gas container 16 and allow the mixed gas to enter the buffer tank 8. As time goes on, the gas in the mixed gas container 16 decreases, gradually approaching a negative pressure state. At this time, the pumping capacity of the first booster pump 7 decreases, so the fifth control valve 24 can be closed, and the second control valve 21 and the third control valve 22 can be opened, allowing vacuum pump 17 to work (at this time, the fourth control valve 23 at vacuum pump 17 has already been closed) and booster pump to be connected in series. This dual-pump series mode can handle mixed gases under extremely low negative pressure conditions that are difficult to collect using traditional techniques. Similarly, after one separation, the extraction of the mixed gas in the exhaust gas tank 10 can also be accomplished in the same manner. During normal operation, the eighteenth control valve 37, the second control valve 21, the fifth control valve 24, and the seventh control valve 26 are opened, and the first booster pump 7 is used to extract the mixed gas in the exhaust gas tank 10. When subsequent extraction capacity is insufficient, the second control valve 21 and the fifth control valve 24 are closed, and the third control valve 22 is opened, connecting the first booster pump 7 and the vacuum pump 17 in series to extract the mixed gas under extremely low negative pressure.

[0042] In some embodiments of this example, a twelfth control valve 31, a second booster pump 15, and a thirteenth control valve 32 are connected in series along the gas flow direction on the detection pipeline 3 between the mass spectrometer 13 and the condenser 12. The second booster pump 15 is mainly used to pump the qualified or unqualified gas after separation into the corresponding product tank 14 or tail gas tank 10.

[0043] Furthermore, in this embodiment, an eleventh control valve 30 is connected in parallel between the inlet end of the twelfth control valve 31 and the outlet end of the thirteenth control valve 32. The function of the eleventh control valve 30 is to cooperate with the vacuum pump 17 to evacuate the vacuum, thereby effectively removing residual gas from both sides of the second booster pump 15.

[0044] Optionally, in this embodiment, the outer shell 901 is a sandwich structure, which is vacuum-sealed and filled with perlite material 19. Vacuuming the sandwich structure not only provides insulation, preventing heat loss due to excessive heat exchange between the cooling medium 903 and the external environment, but also helps to contain the escape of tritium components in the mixed gas. Because tritium components in the mixed gas must be strictly contained to prevent leakage, but they can easily escape the confinement of the outer shell 901 through slow infiltration, the sandwich structure captures the escaping tritium components through negative pressure. Furthermore, vacuuming the sandwich structure and filling it with perlite ensures safe containment of tritium and prevents direct contact burns or frostbite to people.

[0045] Specifically, in this embodiment, a fourth pressure sensor 41 for detecting the pressure inside the sandwich structure is provided. If the fourth pressure sensor 41 detects an abnormal pressure, it indicates that components such as tritium are escaping, requiring further processing. In fact, the sandwich structure in this embodiment is connected to a first row of conduits 46, and a tenth control valve 29 is connected in series on the first row of conduits 46. When the fourth pressure sensor 41 detects an abnormal pressure, the tenth control valve 29 opens, extracting the escaped components captured within the sandwich structure.

[0046] Optionally, in this embodiment, the buffer tank 8, product tank 14, and exhaust gas tank 10 are all sandwich tank structures, and the sandwich layers of the sandwich tank structures are all vacuum-sealed. The principle of the sandwich tank structure is basically the same as that of the vacuuming process in the aforementioned sandwich structures, and will not be further elaborated here. It should be noted that the sandwich layers of the buffer tank 8, product tank 14, and exhaust gas tank 10 in this embodiment are connected to a second row of pipes 47, and control valves are connected in series on these second row of pipes 47. These control valves correspond one-to-one with the buffer tank 8, product tank 14, and exhaust gas tank 10 as the ninth control valve 28, the seventeenth control valve 36, and the fifteenth control valve 34, respectively. The function of the second row of pipes 47 is basically the same as that of the first row of pipes 46. Similarly, the sandwich layers corresponding to the buffer tank 8, product tank 14, and exhaust gas tank 10 are equipped with a third pressure sensor 40, a seventh pressure sensor 44, and a fifth pressure sensor 42.

[0047] It is worth further explaining that, in this embodiment, an eighth control valve 27 is connected in series between the buffer tank 8 and the separator 9. This eighth control valve 27 is mainly used to close when the mixed gas is being filled into the buffer tank 8, preventing the mixed gas in the buffer tank 8 from entering the separator 9 during filling. This allows the gas pressure inside the buffer tank 8 to stabilize before proceeding to the next separation step. In this embodiment, a second pressure sensor 39 is installed at the buffer tank 8 to monitor the pressure value inside the buffer tank 8.

[0048] Similarly, an eighth pressure sensor 45 and a sixth pressure sensor 43 are respectively installed at the product tank 14 and the exhaust gas tank 10 to monitor the pressure values ​​inside the product tank 14 and the exhaust gas tank 10, respectively.

[0049] In this embodiment, in order to control the flow rate of the mixed gas entering the separator 9 from the buffer tank 8, a flow controller 48 is connected in series between the buffer tank 8 and the separator 9 so that the mixed gas flows into the separator 9 at a uniform speed within a predetermined flow rate range, thereby improving the separation effect.

[0050] In addition, it should be noted that in this embodiment, the inlet and outlet of the buffer tank 8, spiral tube 11, tail gas tank 10 and product tank 14 are all connected in series with shut-off valves 38, which can effectively prevent backflow problems.

[0051] Example 2 Please refer to Figure 2 This embodiment provides a process for separating tritium and its isotopes, using the system of Example 1, and includes the following steps: S1: The mixed gas is sent into the separation pipeline through the intake pipeline, and after being pressurized by the first booster pump, it is sent into the buffer tank; S2: The mixed gas in the buffer tank enters the separator. A cooling medium circulator cools the mixed gas in the spiral tube using a cooling medium, causing the different components in the mixed gas to be distributed sequentially in the low-temperature spiral tube due to differences in migration rates. The tritium component, due to its longer adsorption and retention time, flows out later than the other components, resulting in a tritium-depleted initial section and a tritium-rich later section at the outlet. In this step, the cooling medium circulator cools the mixed gas in the spiral tube to -100℃ to -90℃. S3: After the gas flowing out of the separator enters the condenser and is restored to the predetermined temperature, it enters the detection pipeline, where the mass spectrometer detects in real time whether the tritium concentration in the gas is within the acceptable range. S4: Stream split control based on mass spectrometer detection results: If the tritium concentration is within acceptable limits, the gas will be sent into the product tank through the product pipeline. If the tritium concentration is not up to standard, the gas will be sent into the exhaust gas tank through the exhaust gas pipeline. S5: After the separator completes one separation, the unqualified gas in the tail gas tank is drawn back to the inlet end of the first booster pump through the recovery pipeline. After being pressurized by the first booster pump, it is sent back into the buffer tank. Steps S2 to S4 are repeated for cyclic separation. S6: Repeat step S5 until the mass spectrometer can no longer detect a qualified tritium concentration gas, then stop the process.

[0052] Existing low-temperature displacement chromatography and TCAP methods require the use of precious metal materials (such as palladium-loaded alumina or palladium / diatomaceous earth). These materials tend to pulverize, clog, and experience adsorption degradation during repeated hydrogen adsorption and desorption, and radioactive tritium remains within them, leading to decreased recovery rates and the generation of tritium-containing solid waste. Furthermore, helium is required as a carrier gas, increasing gas source costs and the burden of subsequent helium-hydrogen separation. In step S2 of this embodiment, the mixed gas is directly separated within a spiral tube (containing ordinary packing material). The system boasts high long-term operational reliability and produces no tritium-containing solid waste. Simultaneously, no external carrier gas is required, significantly reducing operating costs and system complexity.

[0053] In existing technologies, residual tritium in the exhaust gas after a single separation is often difficult to process again within the same system, limiting tritium recovery rates. In steps S5 and S6 of this invention, by fully recirculating the exhaust gas, all substandard gas is recirculated and used as the sole feed for the next cycle (no new gas is injected after the initial feed). The tritium-rich gas flowing out later is gradually cut off and collected, ultimately ensuring that the tritium in the remaining gas within the system is essentially completely separated. This batch closed-loop circulation mode has the advantages of high tritium recovery rate and no direct exhaust gas emission.

[0054] Furthermore, in steps S3 and S4 of this invention, a mass spectrometer is used for real-time online detection and automatic separation. Qualified gas enters the product tank, while unqualified gas is recycled back into the system. The threshold for qualified concentration can be flexibly set according to actual needs (e.g., 90%–99%), and the number of cycles is automatically controlled by the system until qualified tritium concentration is no longer detectable. This closed-loop control logic of online detection, real-time decision-making, and immediate execution makes the separation purity and recovery rate predictable and controllable, rather than relying on empirical parameters or a fixed number of cycles.

[0055] Furthermore, in existing low-temperature displacement chromatography methods, after tritium is adsorbed by the packing material, it needs to be desorbed by heating or backflushed with helium to obtain the product, which involves many steps, high energy consumption, and long time. In step S2 of this embodiment, the tritium component flows out later than other components, and the tritium-rich gas in the downstream section can be directly obtained from the outlet end without any desorption or backflushing operation, which simplifies the process steps and shortens the operating cycle.

[0056] Optionally, in this embodiment, in step S2 above, the cooling medium circulator cools the mixed gas in the spiral tube to -100℃ to -90℃. The quantum sieving effect (inverse dynamic isotope effect) of hydrogen isotopes is significant in the low-temperature range. The temperature range of -100℃ to -90℃ (i.e., 173K to 183K) selected in this scheme closely matches the low-temperature range where the quantum effect is significant, while retaining an appropriate temperature margin so that the gas in the spiral tube remains in a pure gaseous state and does not condense or blockage.

[0057] In the cryogenic environment of -100℃ to -90℃, the thermal motion speed of gas molecules slows down, the collision frequency between molecules and the tube wall increases, and the influence of the wall effect on molecular migration is significantly enhanced. At low temperatures, the zero-point energy effect and quantum tunneling effect jointly influence the diffusion behavior of isotope molecules. Heavy isotopes have lower zero-point energies than light isotopes, resulting in stronger van der Waals forces with the tube wall material and a longer residence time near the tube wall. Therefore, their migration rate through the helical tube is slower than that of light isotopes. Although classical theory predicts that light isotopes migrate faster than heavy isotopes, in this temperature range, heavy isotopes elute later than light isotopes due to their longer adsorption and retention time. This is the physical basis for the tritium-depleted front and tritium-rich time-series distribution achieved in this embodiment. Therefore, in the cryogenic environment of -100℃ to -90℃, the tritium component elutes from the separator later than other components, and the gas emanating from the latter part is tritium-rich.

[0058] Optionally, in this embodiment, when the gas flowing out of the separator enters the condenser and returns to a predetermined temperature, the predetermined temperature is 20-30°C.

[0059] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A system for separating tritium and its isotopes, characterized in that, This includes intake piping, separation piping, detection piping, product piping, exhaust piping, and recovery piping; The inlet end of the separation pipeline is connected to the outlet end of the air inlet pipeline, and the outlet end of the separation pipeline is connected to the inlet end of the detection pipeline. A first booster pump, a buffer tank, a separator, and a condenser are connected in series along the gas flow direction on the separation pipeline. The separator includes a housing, a cooling medium circulator, a cooling medium, and a spiral tube connected in series in the separation pipeline. The spiral tube is located inside the housing, and the cooling medium fills the space between the housing and the spiral tube. The inlet and outlet of the cooling medium circulator are both connected to the interior of the housing. A mass spectrometer is installed on the detection pipeline to monitor whether the gas in the detection pipeline is up to standard; The outlet end of the detection pipeline is connected to the inlet end of the product pipeline and the inlet end of the exhaust gas pipeline, respectively. The product pipeline is connected to a product tank at its outlet end, and a sixteenth control valve is connected in series on the product pipeline. The fourteenth control valve and the tail gas tank are connected in series along the gas flow direction on the tail gas pipeline. The inlet end of the recovery pipeline is connected to the outlet end of the exhaust gas pipeline, and the outlet end of the recovery pipeline is connected to the inlet end of the first booster pump. An eighteenth control valve is connected in series on the recovery pipeline.

2. The system for separating tritium and its isotopes according to claim 1, characterized in that, The inlet end of the air intake pipe is connected to a mixed gas container. A first control valve and a fifth control valve are sequentially arranged between the mixed gas container and the first booster pump. The first control valve is connected in series on the air intake pipe, and the fifth control valve is connected in series on the separation pipe. A vacuum pump is connected in parallel to the fifth control valve. A second control valve and a third control valve are connected in series on the inlet side and the outlet side of the vacuum pump, respectively. A seventh control valve is provided at the outlet end of the first booster pump, and a sixth control valve is connected in parallel between the outlet end of the seventh control valve and the inlet end of the first booster pump.

3. The system for separating tritium and its isotopes according to claim 2, characterized in that, The outlet of the vacuum pump is also connected to an exhaust pipe, and a fourth control valve is connected in series on the exhaust pipe. The connection point of the exhaust pipe is located between the third control valve and the vacuum pump.

4. The system for separating tritium and its isotopes according to claim 2, characterized in that, The outlet end of the recovery pipeline is connected between the vacuum pump and the second control valve.

5. The system for separating tritium and its isotopes according to claim 2, characterized in that, The detection pipeline between the mass spectrometer and the condenser is connected in series with a twelfth control valve, a second booster pump, and a thirteenth control valve along the gas flow direction.

6. The system for separating tritium and its isotopes according to claim 5, characterized in that, An eleventh control valve is connected in parallel between the inlet of the twelfth control valve and the outlet of the thirteenth control valve.

7. The system for separating tritium and its isotopes according to claim 1, characterized in that, The outer shell is a sandwich structure, which is vacuum-treated and filled with perlite material.

8. The system for separating tritium and its isotopes according to claim 1, characterized in that, The buffer tank, product tank, and exhaust gas tank are all sandwich tank structures, and the sandwich layers of the sandwich tank structures are all vacuum-sealed.

9. A process for separating tritium and its isotopes, characterized in that, The system according to any one of claims 1-8 comprises the following steps: S1: The mixed gas is sent into the separation pipeline through the intake pipeline, and after being pressurized by the first booster pump, it is sent into the buffer tank; S2: The mixed gas in the buffer tank enters the separator. The cooling medium circulation machine cools the mixed gas in the spiral tube through the cooling medium, so that the different components in the mixed gas are distributed sequentially in the low temperature spiral tube due to the difference in migration rate. Among them, the tritium component flows out later than other components because of its longer adsorption retention time. The outlet end forms a time series distribution of tritium-depleted in the front section and tritium-rich in the back section. S3: After the gas flowing out of the separator enters the condenser and is restored to the predetermined temperature, it enters the detection pipeline, where the mass spectrometer detects in real time whether the tritium concentration in the gas is within the acceptable range. S4: Stream split control based on mass spectrometer detection results: If the tritium concentration is within acceptable limits, the gas will be sent into the product tank through the product pipeline. If the tritium concentration is not up to standard, the gas will be sent into the exhaust gas tank through the exhaust gas pipeline. S5: After the separator completes one separation, the unqualified gas in the tail gas tank is drawn back to the inlet end of the first booster pump through the recovery pipeline. After being pressurized by the first booster pump, it is sent back into the buffer tank. Steps S2 to S4 are repeated for cyclic separation. S6: Repeat step S5 until the mass spectrometer can no longer detect a qualified tritium concentration gas, then stop the process.

10. The process for separating tritium and its isotopes according to claim 9, characterized in that, In step S2, the cooling medium circulation machine cools the mixed gas in the spiral tube to -100℃ to -90℃.

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