Device, method and application for volume reduction treatment of tritium-containing wastewater and tritium concentration and purification

Abstract

The present invention discloses a device, method and application for the volume reduction treatment and tritium concentration and purification of tritium-containing wastewater. The device includes a rectification unit, an electrolysis unit and a gas adsorption and separation unit. The rectification unit is connected to the electrolysis unit and then to the gas adsorption and separation unit. In the present invention, first, the advantage of high treatment capacity of rectification is used to separate and concentrate the low-level tritium-containing wastewater, so that the tritium concentration in the wastewater at the stripping end meets the discharge requirements and satisfies the requirements of wastewater treatment. The concentrated tritium water at the enrichment end is converted into hydrogen isotope gas by electrolysis, and then the adsorption separation method is used to separate and purify the tritium gas. While realizing the volume reduction of tritium-containing wastewater, pure tritium resources are obtained, realizing the effective utilization of resources. The rectification process has mild operating conditions, negative pressure operation, and no risk of tritium leakage. The electrolysis and adsorption operation processes are simple, easy to operate, safe and reliable. The organic integration of several separation technologies can meet the disposal requirements of large-capacity tritium-containing wastewater and obtain high-purity tritium products at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and particularly relates to a device, method and application for volume reduction treatment of tritium-containing wastewater and tritium concentration and purification. Background Art

[0002] As an important alternative option to fossil energy, nuclear power has received increasing attention and emphasis, and the global installed capacity of nuclear power plants has been continuously increasing. During the operation of nuclear power reactors, a certain amount of tritium-containing wastewater will be generated, and a certain amount of low-level radioactive tritium-containing wastewater will also be generated during the reprocessing of spent fuel. The volume of tritium-containing wastewater is large, and the specific activity of tritium is not high. With the improvement of people's awareness of ecological environmental protection, the country has also formulated more stringent emission standards, and the original high-altitude discharge or sea discharge methods have been prohibited. These continuously generated tritium-containing wastewaters have a great impact on both nuclear power operation and spent fuel reprocessing. There is an urgent need for an effective method to dispose of these tritium-containing wastewaters so that the tritium content therein can be reduced to the environmental protection emission standards.

[0003] Tritium is a very important radioactive nuclide. It is not only an important raw material for controllable nuclear fusion reactors but also an important tracer, and has important applications in the fields of medicine, biochemistry, petroleum, environmental protection, and hydrology. Therefore, reasonable disposal of tritium-containing wastewater will not only be able to solve the problem of tritium pollution emissions but also realize the recycling and reuse of resources.

[0004] Currently, the methods for tritium separation and concentration mainly include low-temperature distillation, water rectification, electrolysis, thermal diffusion, solvent extraction, molecular laser method, catalytic exchange method, chromatography, and processes and derivative processes that combine two or more of these methods. Among them, most methods such as low-temperature distillation, thermal diffusion, and catalytic exchange method require converting the raw material into hydrogen before separation. For tritium-containing wastewater with low specific activity and large volume, direct conversion is very uneconomical and unrealistic. The electrolysis method also has the problem of small treatment throughput and cannot meet the treatment requirements of large-volume tritium-containing wastewater. Chromatography is a feasible method for the enrichment and separation of hydrogen isotopic gases, but this method cannot be used to directly enrich tritium from tritium-containing wastewater. Therefore, it is necessary to develop a method that not only has the ability to treat large-capacity low-level radioactive tritium-containing wastewater but also has the ability of tritium concentration and purification, so as to solve the problem of tritium pollution emissions while realizing the recycling and reuse of tritium resources. Summary of the Invention

[0005] In order to solve the technical problems existing in the prior art, the purpose of the present invention is to provide a device, method and application for volume reduction treatment of tritium-containing wastewater and tritium concentration and purification.

[0006] To achieve the above object and reach the above technical effect, the technical solution adopted by the present invention is as follows:

[0007] A device for treating tritium-containing wastewater volume reduction and concentrating and purifying tritium, comprising a rectification unit, an electrolysis unit and a gas adsorption and separation unit. The rectification unit is connected to the electrolysis unit and then to the gas adsorption and separation unit. The bottom liquid phase after rectification by the rectification unit enters the electrolysis unit for electrolysis, and the gas generated at the cathode of the electrolysis unit enters the gas adsorption and separation unit for gas adsorption and separation.

[0008] Further, the rectification unit includes a purified raw water tank, a condenser, a reflux intermediate tank, a reboiler, a cooler, a concentrated tritium water tank and a rectification tower unit. The purified raw water tank is connected to the feed inlet of the rectification tower unit through a feed pump. The rectification tower unit includes an N-stage rectification tower. The bottom liquid phase outlet of the first-stage rectification tower is respectively connected to the reboiler and the cooler. The cooler is connected to the concentrated tritium water tank. The top of the last-stage rectification tower is sequentially connected to a condenser and a reflux intermediate tank. The reflux intermediate tank is also connected to the upper reflux port of the last-stage rectification tower.

[0009] Further, N is any integer from 1 to 20. The height of the rectification tower is 1 m to 50 m, and the tower diameter is 0.01 m to 10 m.

[0010] Further, the outlet at the top of the (N - 1)-th stage rectification tower is connected to the inlet at the bottom of the N-th stage rectification tower, and the outlet at the bottom of the N-th stage rectification tower is connected to the inlet at the top of the (N - 1)-th stage rectification tower.

[0011] Further, the rectification unit is connected to a vacuum system, and the working pressure is an absolute pressure of 300 mmHg to 650 mmHg.

[0012] Further, the electrolysis unit includes an electrolytic cell and a first gas collection tank. The concentrated tritium water tank of the rectification unit is connected to the electrolytic cell, and the electrolytic cell is connected to the first gas collection tank.

[0013] Further, the gas adsorption and separation unit includes a carrier gas tank, a hydrogen isotope adsorption and separation device, a detection device, a carrier gas separation device, a second gas collection tank and a gas oxidation device. The carrier gas tank is connected to the feed inlet of the hydrogen isotope adsorption and separation device. The first gas collection tank of the electrolysis unit is connected to the feed inlet of the hydrogen isotope adsorption and separation device through a hydrogen pump. A detection device is provided at the outlet of the hydrogen isotope adsorption and separation device. The outlet of the hydrogen isotope adsorption and separation device is connected to the carrier gas separation device. The outlet of the carrier gas separation device is connected to the second gas collection tank and a gas storage tank. The gas storage tank is connected to the first gas collection tank of the electrolysis unit and the gas oxidation device. The gas oxidation device is connected to the purified raw water tank of the rectification unit.

[0014] Further, the discharge port of the hydrogen isotope adsorption and separation device is connected to the gas separation valve through a tee, the gas separation valve is connected to the intake port of the carrier gas separation device, and the gas storage tank is respectively communicated to the first gas collection tank and the gas oxidation device through a gas pump.

[0015] The present invention also discloses a method for the volume reduction treatment of tritium-containing wastewater and the concentration and purification of tritium, which includes the following steps:

[0016] The raw water in the purified raw water tank enters the rectification unit. The last-stage rectification column has the largest treatment throughput. Through the gas-liquid mass transfer and heat transfer exchange in the last-stage rectification column, tritium in the raw water is enriched in the bottom liquid phase of the last-stage rectification column. The gas phase at the top of the last-stage rectification column enters the reflux intermediate tank after being condensed by a condenser. At this time, the concentration of tritium in the condensate has reached the discharge standard. Part of the condensate in the reflux intermediate tank returns to this stage of the rectification column, and the other part flows out from the qualified water outlet as qualified material. The bottom liquid phase of the last-stage rectification column enters the previous-stage rectification column and is concentrated step by step until it enters the first-stage rectification column. A concentrated tritium water with a concentration of 5-10% is obtained at the bottom of the first-stage rectification column. In the liquid flowing out from the bottom of the first-stage rectification column, tritium is concentrated. Part of the liquid flows into the reboiler, is heated and vaporized, and the steam returns to the bottom of this stage of the column and flows upward. The other part of the liquid enters the concentrated tritium water tank after being cooled by a cooler and is collected;

[0017] The liquid in the concentrated tritium water tank enters the electrolytic cell for electrolysis. The oxygen generated at the anode is discharged, and the hydrogen generated at the cathode is collected into the first gas collection tank;

[0018] The hydrogen in the first gas collection tank enters the hydrogen isotope adsorption and separation device under the action of a hydrogen pump, and the carrier gas in the carrier gas tank also enters the hydrogen isotope adsorption and separation device. The hydrogen completes adsorption and separation in the hydrogen isotope adsorption and separation device, separating different hydrogen isotope gases. According to the desorption time of different hydrogen isotope gases, the gas separation valve is switched, and the gases output at different times enter the carrier gas separation device, obtaining three streams of gas: pure tritium gas, mixed gas I, and hydrogen carrier gas mixed gas II. The pure tritium gas is collected into the second gas collection tank, the mixed gas I is collected into the gas storage tank, and the hydrogen carrier gas mixed gas II is discharged; after the mixed gas I in the gas storage tank is rebalanced, it is pumped into the first gas collection tank by a gas pump and enters the hydrogen isotope adsorption and separation device and the carrier gas separation device again for separation. After several cycles, the gas in the gas storage tank enters the gas oxidation device and reacts with the oxygen entering the gas oxidation device to become hydrogen isotope water and then returns to the purified raw water tank.

[0019] The present invention also discloses the application of a device for the volume reduction treatment of tritium-containing wastewater and the concentration and purification of tritium in the treatment of radioactive wastewater.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] The present invention discloses a device, method and application for the volume reduction treatment of tritium-containing wastewater and the concentration and purification of tritium. The device mainly includes the following components: a rectification unit, an electrolysis unit and a gas adsorption and separation unit. The rectification unit is connected to the electrolysis unit and then to the gas adsorption and separation unit. The bottom liquid phase after rectification in the rectification unit enters the electrolysis unit for electrolysis. The oxygen generated at the anode in the electrolysis unit is discharged, and the hydrogen generated at the cathode enters the gas adsorption and separation unit for gas adsorption and separation to separate different hydrogen isotope gases. It has the ability to treat a large volume of low-level tritium-containing wastewater and also has the ability to concentrate and purify tritium. While solving the problem of tritium pollution emission, it realizes the recycling of tritium resources. In the present invention, first, the low-level tritium-containing wastewater is separated and concentrated by utilizing the advantage of high treatment capacity of rectification, so that the tritium concentration in the wastewater at the stripping end meets the emission requirements and satisfies the requirements of wastewater treatment. The concentrated tritium water at the enrichment end is converted into hydrogen isotope gas by electrolysis, and then the adsorption separation method is used to separate and purify tritium gas. While realizing the volume reduction of tritium-containing wastewater, pure tritium resources are obtained, and the effective utilization of resources is realized. The operation conditions of the rectification process are mild, with negative pressure operation and no risk of tritium leakage. The electrolysis and adsorption operation processes are simple, easy to operate, safe and reliable. The organic integration of several separation technologies can meet the disposal requirements of a large volume of tritium-containing wastewater and obtain high-purity tritium products at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention will be elaborated in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0024] The following gives a brief overview of one or more aspects to provide a basic understanding of these aspects. This overview is not an exhaustive survey of all contemplated aspects, and is neither intended to identify key or decisive elements of all aspects nor to attempt to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[0025] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0026] On the one hand, the present invention provides a device for treating and concentrating and purifying tritium-containing wastewater. As Figure 1 shown, this device combines three technologies: rectification, electrolysis, and hydrogen adsorption separation. While treating and reducing the volume of tritium-containing wastewater, it concentrates and purifies the tritium in the wastewater, and finally can obtain utilizable tritium resources. Specifically, the device for treating and concentrating and purifying tritium-containing wastewater provided by the present invention mainly includes the following components: a rectification unit, an electrolysis unit, and a gas adsorption separation unit. The rectification unit is connected to the electrolysis unit and then to the gas adsorption separation unit. The bottom liquid phase after rectification by the rectification unit enters the electrolysis unit for electrolysis. The oxygen generated at the anode of the electrolysis unit is discharged, and the hydrogen generated at the cathode enters the gas adsorption separation unit for gas adsorption separation to separate different hydrogen isotope gases.

[0027] The rectification unit includes a purified raw water tank 1, a condenser 4, a reflux intermediate tank 5, a reboiler 6, a cooler 7, a concentrated tritium water tank 8, and a rectification tower unit. The rectification tower unit includes an N-stage rectification tower 3, where N is any integer from 1 to 20. The purified raw water tank 1 is connected to the feed inlet of the rectification tower unit through a feed pump 2, and the feed inlet of the rectification tower unit is arranged on the last-stage rectification tower 3 in the rectification tower unit; the bottom liquid phase outlet of the first-stage rectification tower 3 is respectively connected to the reboiler 6 and the concentrated tritium water tank 8. In the liquid flowing out from the bottom of the first-stage rectification tower 3, tritium is concentrated. A part of the liquid flows into the reboiler 6, is heated and vaporized, and the steam returns to the bottom of this stage and flows upward. Another part of the liquid is cooled by the cooler 7 and then enters the concentrated tritium water tank 8 for collection; the top of the last-stage rectification tower 3 is successively connected to a condenser 4 and a reflux intermediate tank 5. The lower outlet of the reflux intermediate tank 5 is respectively connected to the upper reflux port and the qualified water outlet of this stage of the rectification tower 3 through a reflux pump. The gas phase at the top of the last-stage rectification tower 3 enters the reflux intermediate tank 5 after being condensed by the condenser 4. At this time, the concentration of tritium in the condensate has reached the discharge standard. Therefore, a part of the condensate in the reflux intermediate tank 5 returns to the upper reflux port of this stage of the rectification tower 3 and flows downward, and another part flows out as qualified materials from the qualified water outlet.

[0028] The top outlet of the first-stage rectification tower 3 is connected to the bottom inlet of the second-stage rectification tower 3, the top outlet of the second-stage rectification tower 3 is connected to the bottom inlet of the third-stage rectification tower 3, and so on. That is, the top outlet of the (N - 1)-stage rectification tower 3 is connected to the bottom inlet of the N-stage rectification tower 3; the bottom outlet of the second-stage rectification tower 3 is connected to the top inlet of the first-stage rectification tower 3, the bottom outlet of the third-stage rectification tower 3 is connected to the top inlet of the second-stage rectification tower 3, and so on. That is, the bottom outlet of the N-stage rectification tower 3 is connected to the top inlet of the (N - 1)-stage rectification tower 3.

[0029] The rectification unit is connected to the vacuum system and operates at an absolute pressure of 300 mmHg to 650 mmHg. The rectification tower 3 has a height of 1 m to 50 m and a diameter of 0.01 m to 10 m.

[0030] The electrolysis unit includes an electrolytic cell 9 and a first gas collection tank 10. The concentrated tritium water tank 8 is connected to the electrolytic cell 9, and the electrolytic cell 9 is connected to the first gas collection tank 10. The liquid in the concentrated tritium water tank 8 is sent into the electrolytic cell 9 by a concentrated tritium pump 21 for electrolysis. The oxygen generated at the anode is discharged, and the hydrogen generated at the cathode is collected in the first gas collection tank 10, which is convenient for later hydrogen isotope adsorption and separation in the hydrogen isotope adsorption and separation device 13 of the gas adsorption and separation unit.

[0031] The gas adsorption and separation unit includes a carrier gas tank 12, a hydrogen isotope adsorption and separation device 13, a detection device 14, a gas separation valve 15, a carrier gas separation device 16, a second gas collection tank 17, and a gas oxidation device 20. The carrier gas tank 12 is connected to the feed port of the hydrogen isotope adsorption and separation device 13. The first gas collection tank 10 is connected to the feed port of the hydrogen isotope adsorption and separation device 13 through a hydrogen pump 11. A detection device 14 is provided at the discharge port of the hydrogen isotope adsorption and separation device 13. The discharge port of the hydrogen isotope adsorption and separation device 13 is connected to the gas separation valve 15 through a tee. The gas separation valve 15 is connected to the inlet of the carrier gas separation device 16. The outlet of the carrier gas separation device 16 is respectively connected to the second gas collection tank 17 and a gas storage tank 18. The gas storage tank 18 is respectively connected to the first gas collection tank 10 and the gas oxidation device 20 through a gas pump 19. The gas oxidation device 20 is connected to the purified raw water tank 1.

[0032] On the other hand, the present invention also discloses a method for reducing the volume of tritium-containing wastewater and concentrating and purifying tritium, including the following steps:

[0033] The raw water in the purified raw water tank 1 is sent into the feed port of the rectification unit by the feed pump 2. The treatment throughput of the last-stage rectification column 3 is the largest, mainly playing a role in stripping. Through the gas-liquid mass transfer and heat transfer exchange in the last-stage rectification column 3, the tritium in the raw water is mainly enriched in the bottom liquid phase of the last-stage rectification column 3. The tritium content in the gas phase coming out from the top of the last-stage rectification column 3 can meet the emission requirements. The gas phase at the top of the last-stage rectification column 3 enters the reflux intermediate tank 5 after being condensed by the condenser 4. At this time, the concentration of tritium in the condensate has reached the emission standard. Therefore, a part of the condensate in the reflux intermediate tank 5 returns to the upper reflux port of this stage of the rectification column 3 and flows downward in a reflux manner, and the other part flows out as qualified material from the qualified water outlet. The bottom liquid phase of the last-stage rectification column 3 enters the previous-stage rectification column 3 to continue concentration, and then enters the pre-previous-stage rectification column 3,... and is concentrated stage by stage until it enters the first-stage rectification column 3 and reaches the designed concentration requirement. Here, when using the rectification unit for rectification separation, the bottom liquid phase of the Nth-stage rectification column 3 enters the N-1th-stage rectification column 3 from the top of the N-1th-stage rectification column 3, and the gas phase at the top of the N-1th-stage rectification column 3 enters the Nth-stage rectification column 3 from the bottom of the Nth-stage rectification column 3. Concentrated tritium water with a concentration of 5-10% is obtained at the bottom of the first-stage rectification column 3. In the liquid flowing out from the bottom of the first-stage rectification column 3, tritium is concentrated. A part of the liquid flows into the reboiler 6, is heated and vaporized, and the steam returns to the bottom of this stage and flows upward. The other part of the liquid enters the concentrated tritium water tank 8 after being cooled by the cooler 7 and is collected for later feeding into the electrolytic cell 9 for electrolysis;

[0034] The liquid in the concentrated tritium water tank 8 is sent into the electrolytic cell 9 by the concentrated tritium pump 21 for electrolysis. The oxygen generated at the anode is discharged, and the hydrogen generated at the cathode is collected into the first gas collection tank 10 for later entry into the hydrogen isotope adsorption separation device 13 of the gas adsorption separation unit for hydrogen isotope adsorption separation;

[0035] The hydrogen gas in the first gas collection tank 10 enters the hydrogen isotope adsorption and separation device 13 through the feed port of the hydrogen isotope adsorption and separation device 13 under the action of the hydrogen pump 11. The carrier gas in the carrier gas tank 12 also enters the hydrogen isotope adsorption and separation device 13 through the feed port of the hydrogen isotope adsorption and separation device 13. The hydrogen gas completes adsorption and separation within the hydrogen isotope adsorption and separation device 13, separating different hydrogen isotope gases. According to the detection of the detection device 14, the gas separation valve 15 is switched, and the gas output in a time-sharing manner enters the carrier gas separation device 16, obtaining three streams of gas: pure tritium gas T2 (with a concentration reaching over 99.5%), mixed gas I (T2, DT, D2, HT, HD), and hydrogen carrier gas mixed gas II. The pure tritium gas T2 is collected in the second gas collection tank 17, the mixed gas I is collected in the gas storage tank 18, and the hydrogen carrier gas mixed gas II is discharged; after the mixed gas I in the gas storage tank 18 is rebalanced, it is pumped into the first gas collection tank 10 by the gas pump 19 and enters the hydrogen isotope adsorption and separation device 13 and the carrier gas separation device 16 again for separation. After several cycles, the gas in the gas storage tank 18 is sent into the gas oxidation device 20 by the gas pump (19), reacts with the oxygen entering the gas oxidation device 20 to become hydrogen isotope water, and then returns to the purified raw water tank 1 again.

[0036] The hydrogen isotope adsorption and separation device 13 uses a low-temperature stripping column or a normal-temperature displacement column, etc. for separation operations.

[0037] Meanwhile, the present invention also discloses the application of a device for tritium-containing wastewater volume reduction treatment and tritium concentration and purification in radioactive wastewater treatment, especially in tritium-containing wastewater treatment.

[0038] Example 1

[0039] The tritium concentration in the low-level radioactive wastewater is 1.5×10 9Bq / L. The rectification unit includes a four-stage rectification tower 3 with the liquid phases of the four towers in cascade connection. The outlet at the top of the first-stage rectification tower 3 is connected to the inlet at the bottom of the second-stage rectification tower 3, the outlet at the top of the second-stage rectification tower 3 is connected to the inlet at the bottom of the third-stage rectification tower 3, and so on. The outlet at the bottom of the second-stage rectification tower 3 is connected to the inlet at the top of the first-stage rectification tower 3, the outlet at the bottom of the third-stage rectification tower 3 is connected to the inlet at the top of the second-stage rectification tower 3, and so on. The throughput is 500 kg / h and the operating pressure is 500 mmHg. After the system reaches equilibrium, the tritium concentration in the material withdrawn from the top of the fourth-stage rectification tower 3 (i.e., the last-stage rectification tower 3) is 95.8 Bq / L, and the tritium concentration in the material discharged from the bottom of the first-stage rectification tower 3 is 10%, which is concentrated tritiated water. After electrolysis and adsorption separation of the concentrated tritiated water, pure tritium gas T2 with a concentration of over 99.5% is collected and stored in the second gas collection tank 17. The mixed gas I is collected in the gas storage tank 18, and the hydrogen carrier mixed gas II is discharged. After the mixed gas I in the gas storage tank 18 reaches a new equilibrium, it is pumped into the first gas collection tank 10 by the air pump 19 and re-enters the hydrogen isotope adsorption separation device 13 and the carrier gas separation device 16 for separation. After two cycles of circulation, the gas in the gas storage tank 18 is sent into the gas oxidation device 20 by the air pump 19, reacts with the oxygen entering the gas oxidation device 20 to become hydrogen isotope water, and then returns to the purified raw water tank 1.

[0040] For parts or structures not specifically described in the present invention, existing technologies or existing products can be adopted, and no further elaboration will be made here.

[0041] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made using the content of the specification of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. An apparatus for the volume reduction treatment of tritium-containing wastewater and the concentration and purification of tritium, characterized in that, It includes a rectification unit, an electrolysis unit and a gas adsorption and separation unit. The rectification unit is in communication with the electrolysis unit, and the electrolysis unit is in communication with the gas adsorption and separation unit. The bottom liquid phase after rectification by the rectification unit enters the electrolysis unit for electrolysis, and the gas generated at the cathode of the electrolysis unit enters the gas adsorption and separation unit for gas adsorption and separation; The gas adsorption and separation unit includes a carrier gas tank, a hydrogen isotope adsorption and separation device, a detection device, a carrier gas separation device, a second gas collection tank and a gas oxidation device. The carrier gas tank is in communication with the feed inlet of the hydrogen isotope adsorption and separation device. The first gas collection tank of the electrolysis unit is connected to the feed inlet of the hydrogen isotope adsorption and separation device through a hydrogen pump. A detection device is provided at the discharge outlet of the hydrogen isotope adsorption and separation device. The discharge outlet of the hydrogen isotope adsorption and separation device is connected to the carrier gas separation device. The gas outlet of the carrier gas separation device is in communication with the second gas collection tank and the gas storage tank. The gas storage tank is connected to the first gas collection tank of the electrolysis unit and the gas oxidation device. The gas oxidation device is in communication with the purified raw water tank of the rectification unit.

2. The device for treating and concentrating and purifying tritium-containing wastewater according to claim 1, wherein The rectification unit includes a purified raw water tank, a condenser, a reflux intermediate tank, a reboiler, a cooler, a concentrated tritium water tank and a rectification tower unit. The purified raw water tank is connected to the feed inlet of the rectification tower unit through a feed pump. The rectification tower unit includes an N-stage rectification tower. The bottom liquid phase outlet of the first-stage rectification tower is respectively connected to the reboiler and the cooler. The cooler is connected to the concentrated tritium water tank. The top of the last-stage rectification tower is successively connected to the condenser and the reflux intermediate tank. The reflux intermediate tank is also connected to the upper reflux port of the last-stage rectification tower.

3. The device for tritium-containing wastewater volume reduction treatment and tritium concentration and purification according to claim 2, characterized in that, N is any integer from 1 to 20. The height of the rectification tower is 1 m to 50 m, and the tower diameter is 0.01 m to 10 m.

4. A device for treating tritium-containing wastewater to reduce its volume and concentrating and purifying tritium according to claim 2, characterized in that, The top outlet of the (N - 1)-th stage rectification tower is in communication with the bottom inlet of the N-th stage rectification tower, and the bottom outlet of the N-th stage rectification tower is in communication with the top inlet of the (N - 1)-th stage rectification tower.

5. The device for tritium-containing wastewater volume reduction treatment and tritium concentration and purification according to claim 2, wherein, The rectification unit is in communication with a vacuum system, and the working pressure is an absolute pressure of 300 mmHg to 650 mmHg.

6. The device for tritium-containing wastewater volume reduction treatment and tritium concentration and purification according to claim 1, characterized in that, The electrolysis unit includes an electrolytic cell and a first gas collection tank. The concentrated tritium water tank of the rectification unit is in communication with the electrolytic cell, and the electrolytic cell is in communication with the first gas collection tank.

7. The device for treating and reducing the volume of tritium-containing wastewater and concentrating and purifying tritium according to claim 1, wherein The discharge outlet of the hydrogen isotope adsorption and separation device is connected to a gas separation valve through a tee. The gas separation valve is connected to the inlet of the carrier gas separation device. The gas storage tank is respectively connected to the first gas collection tank and the gas oxidation device through a gas pump.

8. A method for volume reduction treatment of tritium-containing wastewater and tritium concentration and purification, characterized in that, It includes the following steps: The raw water in the purified raw water tank enters the distillation unit. The processing throughput of the last distillation tower is the largest. Through the gas-liquid mass transfer and heat transfer exchange of the last distillation tower, the tritium in the raw water is enriched in the liquid phase at the bottom of the last distillation tower. The gas phase at the top of the last distillation tower is condensed by the condenser and enters the reflux intermediate tank. At this time, the tritium concentration in the condensate has reached the emission standard. Part of the condensate in the reflux intermediate tank returns to the distillation tower of this stage, and the other part flows out of the qualified water outlet as qualified material. The liquid phase at the bottom of the last distillation tower enters the previous distillation tower and is concentrated step by step until it enters the first distillation tower. At the bottom of the first distillation tower, concentrated tritium water with a concentration of 5-10% is obtained. The tritium is concentrated in the liquid flowing out of the bottom of the first distillation tower. Part of the liquid flows into the reboiler, is heated and vaporized, and the steam returns to the bottom of the tower of this stage and flows upward. The other part of the liquid is cooled by the cooler and collected in the concentrated tritium water tank. The liquid in the concentrated tritium water tank enters the electrolytic cell for electrolysis, the oxygen produced at the anode is discharged, and the hydrogen produced at the cathode is collected in the first gas collection tank; The hydrogen in the first gas collection tank enters the hydrogen isotope adsorption separation device under the action of the hydrogen pump. The carrier gas in the carrier gas tank also enters the hydrogen isotope adsorption separation device. The hydrogen is adsorbed and separated in the hydrogen isotope adsorption separation device to separate the different hydrogen isotope gases. The gas separator valve is switched according to the desorption time of the different hydrogen isotope gases, and the time-sharing output gases enter the carrier gas separation device to obtain three gas streams: pure tritium gas, mixed gas I, and hydrogen carrier gas mixed gas II. The pure tritium gas is collected in the second gas collection tank, the mixed gas I is collected in the gas temporary storage tank, and the hydrogen carrier gas mixed gas II is discharged. After the mixed gas I in the gas temporary storage tank is rebalanced, it is pumped into the first gas collection tank via the air pump and re-enters the hydrogen isotope adsorption separation device and the carrier gas separation device for separation. After several cycles, the gas in the gas temporary storage tank enters the gas oxidation device, reacts with the oxygen entering the gas oxidation device to form hydrogen isotope water, and then returns to the purified raw water tank.

9. Use of the device for volume reduction treatment of tritium-containing wastewater and tritium concentration and purification according to any one of claims 1 to 7 in the treatment of radioactive wastewater.

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