Improvements in tritium extraction and recovery in fusion power generation systems

Abstract

A tritium extraction and recovery apparatus (100) and method for integration in a fusion power generation system is described. The technique includes, in a tritium extraction unit (102), mixing a fluid tritium breeding composition (120) with a second fluid (122) to produce a mixed fluid (110) for a two-phase flow, and extracting tritium from the breeding composition in the two-phase flow by a simultaneous process of penetration through a solid membrane (118) and tritium transfer onto the second fluid (i.e., gas-liquid or liquid-liquid contact). A corresponding fusion power generation system is also described.

Description

Technical Field

[0001] The present disclosure relates generally to tritium breeding in fusion power generation systems and more particularly to an improved tritium extraction and recovery system (TERS) for use with a liquid breeder. Background Art

[0002] Currently, fusion reactors that rely on magnetic confinement, primarily those designed according to the tokamak principle, utilize fusion fuels that include a mixture of deuterium and tritium (i.e., hydrogen isotopes). While deuterium is easily available, such as by extracting it from seawater, natural tritium is very scarce; current estimates place the amount of tritium on Earth at just 20 kilograms (kg), and the current cost is about $30,000 per gram. DEMO, a demonstration power plant planned as a follow-up to ITER, is estimated to require 300 grams of tritium per day to generate electricity continuously. The Spherical Tokamak for Energy Production (STEP), which is used to produce energy, is similarly estimated to require hundreds of grams per day to operate continuously. Therefore, it is necessary to find a technology to produce tritium for fusion reactors.

[0003] Interestingly, neutrons reacting with lithium can produce tritium. Neutrons are, of course, produced by fusion reactors, so one technique for producing tritium is to coat the reactor with lithium blankets. This, of course, raises the question of how to recover the tritium produced in the blankets used in the reactors. One method of extracting tritium is permeation against vacuum (PAV), whereby the tritium is allowed to leave the fluid by transferring across a hydrogen permeable membrane into a vacuum vessel. Another method is through gas liquid contactors (GLCs), which separate tritium from liquid breeders by bringing the liquid breeders into direct contact with a gas, and due to the formation of a concentration gradient, the tritium is transferred to the gas phase. Neither of these methods is particularly efficient; for example, PAV efficiencies are typically reported to be between 5-39%, with recent PAV designs reporting tritium recoveries as high as 80%.

[0004] It is particularly desirable to improve recovery efficiency, as this would allow for a reduction in the tritium inventory in the breeder blanket and associated in-vessel-component (IVC), and reduce the footprint of the TERS. It is therefore desirable to develop improved and / or alternative tritium breeder technologies with improved recovery efficiency to fuel fusion systems. Summary of the invention

[0005] The invention is defined according to the independent claims. Additional features will be understood from the dependent claims and the description herein. Any embodiments described but not falling within the scope of the claims are merely interpreted as examples that help to better understand the invention.

[0006] Exemplary embodiments have been provided to address at least some of the difficulties encountered with current tritium extraction and recovery methods, whether such difficulties have been specifically mentioned above or will be understood from the discussion herein.

[0007] In summary, the present technology is directed to an integrated process by which tritium is extracted by permeation and gas-liquid (or liquid-liquid) contact separation. Advantages of the integrated contactor-permeator now described include increased efficiency of tritium recovery, reduced residence time of tritium in the system, thereby allowing for smaller equipment, lower tritium inventory, and ease of compatibility with conventional breeder systems, including similar manufacturing, installation, and maintenance considerations as conventional PAV systems, thereby reducing the risks associated with adopting the technology.

[0008] Therefore, in one aspect of the present invention, there is provided an apparatus for tritium extraction and recovery in a fusion power generation system. The apparatus comprises a manifold configured to contain a first fluid of a tritium breeding composition and to contain a second fluid, and to output a mixed fluid undergoing a two-phase flow; the breeding composition forms the carrier phase of the two-phase flow, and the second fluid forms the other phase. The apparatus also comprises a tritium extraction unit configured to contain the mixed fluid and to extract tritium from the breeding composition in the two-phase flow by a combination of the following processes: (i) a process of tritium permeating through a hydrogen permeable solid boundary / membrane, and simultaneously (ii) a process of tritium transfer to the second fluid (i.e., gas-liquid or liquid-liquid contact). The two-phase flow provides the dual benefit of allowing two different extraction mechanisms to be used in the same apparatus, while also enhancing the permeation aspect of tritium extraction.

[0009] Preferably, the second fluid (e.g., an inert gas or a molten salt) has a higher affinity for tritium than the first fluid. In particular, the choice of the second fluid may vary depending on the choice of the breeding composition. For example, where the tritium breeding composition is formed of pure liquid lithium, the second fluid may preferably be a molten salt, such as lithium chloride, and where the tritium breeding composition is formed of lead lithium liquid metal (PbLi) or a lithium-based molten salt, such as FLiBe (a mixture of lithium fluoride (LiF) and beryllium fluoride (BeF2)), the second fluid may include an inert gas, preferably helium.

[0010] In one example, the tritium extraction unit is arranged to include a first channel, a second channel and a hydrogen permeable membrane located between the first channel and the second channel (i.e., connecting the first and second channels). The first channel is arranged to accommodate the mixed fluid that undergoes a two-phase flow, and the second channel is arranged to receive tritium from the first channel through the hydrogen permeable membrane; the second channel can be under vacuum pressure or include a purge gas flow. In some examples, the tritium extraction unit includes a third channel, which is arranged on a side of the second channel opposite to the first channel, separated from the second channel by the hydrogen permeable membrane (and connected to the second channel), and the third channel is also arranged to accommodate a mixed fluid consisting of a proliferation composition and a second fluid that undergoes a two-phase flow. Preferably, the channel is formed in a planar arrangement, and when the unit is used, the channel in a planar arrangement can be flush with the ground.

[0011] In another aspect of the present invention, a nuclear fusion power generation system is provided. The system includes a vacuum vessel, a tritium breeding blanket, the tritium breeding blanket (at least partially) surrounds the inner wall or outer wall of the plasma vacuum vessel, and the plasma vacuum vessel is filled with a fluid tritium breeding composition (e.g., pure lithium or PbLi or FLiBe). The system also includes a tritium extraction and recovery device, the tritium extraction and recovery device includes a manifold and a tritium extraction unit, the manifold is configured to accommodate the fluid tritium breeding composition and a second fluid to output a mixed fluid for two-phase flow, the tritium extraction unit is configured to accommodate the mixed fluid, and extract tritium from the breeding composition by a combination of tritium permeating through a hydrogen permeable solid boundary / membrane and simultaneously transferring tritium to the second fluid. Such a system may also include other suitable components, such as a tritium storage unit.

[0012] Suitably, in another aspect of the invention, there is provided a method of extracting tritium from a fluid tritium breeder composition. The method comprises combining the tritium breeder composition with a second fluid to produce a mixed fluid undergoing a two-phase flow, extracting tritium from the breeder composition within the two-phase flow by simultaneous permeation through a hydrogen permeable solid boundary / membrane and transfer of tritium to the second fluid (i.e., gas-liquid contact). BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For a better understanding of the present disclosure, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0014] FIG1 shows a process schematic diagram of a fusion power generation system, including an exemplary tritium extraction and recovery process;

[0015] FIG2 shows an example of a reverse vacuum infiltration process;

[0016] Figure 3 A process schematic diagram of an improved exemplary tritium extraction and recovery system is shown;

[0017] Figure 4 An exemplary tritium extraction unit for an exemplary tritium extraction and recovery system is shown;

[0018] FIG5 shows an exemplary two-phase flow and associated tritium distribution;

[0019] Figure 6 Further illustrated are exemplary various two-phase flows. DETAILED DESCRIPTION

[0020] At least some of the following exemplary embodiments provide an improved tritium extraction and recovery technique.Other advantages and improvements are also apparent from the embodiments discussed herein.

[0021] FIG1 shows a simplified process diagram of a prior art breeding system. Here, a reactor 10 uses deuterium and tritium as fusion fuels, and the reaction of deuterium and tritium produces neutrons. The fusion reaction occurs in the reactor vacuum vessel 11, and the neutrons penetrate the wall of the vacuum vessel 11 and enter the breeding blanket 24. A fluid containing tritium / tritiated material (in the form of coolant or breeding liquid) is pumped out from the blanket 24 so that tritium can be extracted through a suitable tritium extraction and recovery system 16. The extraction and recovery system 16 includes a unit for extracting tritium from the breeding liquid, either a permeator against vacuum unit 30 or a gas-liquid contactor 32, and a device 34 for regulating and storing tritium. After a period of time, the recovered tritium is circulated from the storage 34 to the reactor through a suitable material injection system 18.

[0022] By way of example, FIG2 shows an example of a conventional reverse vacuum permeator "PAV" cell 30. The cell 30 includes a channel for transporting liquid breeder (e.g., lithium lead, PbLi) enriched with tritium (from the breeder blanket 24), and a vacuum channel, the liquid breeder being separated from the vacuum channel by a membrane through which tritium can pass. In FIG2, the breeder liquid entering from the left hand side of the PAV is significantly depleted of tritium as it passes from left to right, and tritium permeates into the vacuum channel. The liquid breeder, now having a low concentration of tritium, is pumped back to the breeder blanket 24 to breed tritium again from neutron interactions.

[0023] Figure 3A process schematic diagram of an improved technique for tritium extraction and recovery in a fusion power generation system is shown, wherein an exemplary improved tritium extraction and recovery apparatus (or system) 100 is used. Notably, the apparatus 100 includes a tritium extraction unit 102, which is configured to extract tritium from a breeder composition supplied to the unit 102 using a process of permeation and simultaneous gas-liquid (or liquid-liquid) contact. That is, the tritium extraction unit extracts tritium from the breeder composition using tritium permeation through a solid, similar to known PAVs, while also promoting the transfer of tritium to a second fluid phase because a concentration gradient is formed between the breeder composition and the second fluid.

[0024] The apparatus 100 suitably includes a manifold 104 that supplies fluids to the tritium extraction unit 102. More specifically, the manifold 104 is configured to receive a first fluid of a tritium breeder composition from the breeder blanket 24, and also receive a second fluid from, for example, a reservoir 106 (although it should be understood that the exact source of the second fluid may vary). The tritium breeder composition may be at least one of a lithium-based salt, a lithium-based liquid metal, or a lithium-based alloy, while the second fluid may be at least one of an inert gas or a lithium-based salt (where this is also not the first fluid).

[0025] The manifold 104 is configured to mix the two fluids into a two-phase flow, wherein the first fluid / breeding agent composition forms a carrier phase and the second fluid forms another phase (second phase). In the example shown, the manifold is configured to mix the fluids prior to supplying the tritium extraction unit 102 for initial tritium extraction. However, in another example (not shown), the manifold may be disposed within the tritium extraction unit 102 (in which case the following description of the tritium extraction unit 102 therefore applies to the portion of the tritium extraction unit 102 after the manifold 104).

[0026] As the mixed fluids proceed through the tritium extraction unit 102, at least some tritium is extracted from the first phase (i.e., the breeder composition) by a permeation process and suitably recovered by delivery to the conditioning and storage unit 34 in this example. In addition, at least some tritium is extracted from the first phase / breeder composition by transfer to a second phase fluid, which is suitably recovered after the two-phase fluid has exited the tritium extraction unit 102 and after the mixed fluids have been separated back into two separate fluids. That is, the separated fluid breeder composition is returned to the breeder blanket 24 for tritium generation (i.e., closing the breeder fluid loop), while the separated second fluid (rich in tritium) is delivered for further processing to recover tritium for later use. Specific methods for separating the breeder composition from the second fluid and subsequently recovering tritium from the second fluid will be readily understood by those skilled in the art of gas-liquid contacting; for example, recovery of tritium from the second fluid may be incorporated as part of the conditioning and storage unit 34.

[0027] It will also be appreciated that in some exemplary arrangements, the extracted tritium may not require storage, but may be suitably returned directly to the reactor via, for example, the material injection system 18. Similarly, tritium extracted by permeation and tritium extracted from the second fluid need not follow the same final route to the storage / reactor (although this may be preferred for simplicity of construction and maintenance, etc.); for example, tritium extracted by permeation may be suitable for direct recycling to the reactor 10, while tritium extracted by transfer to the second fluid may be more suitable for storage.

[0028] Figure 4 An exemplary tritium extraction cell 102 is shown in greater detail. The tritium extraction cell 102 includes a first channel 108 arranged to receive a mixed fluid 110 in a two-phase flow; here illustrated by a fluid of primarily a tritium breeder composition 120 in which bubbles of a second fluid, such as helium 122, are interspersed (although other inert gases may also be used as the second fluid, such as argon). The channel 108 carries the mixed fluid 110 from a first end 112 of the cell 102 to a second end 114 of the cell 102; that is, the first end 112 may be considered the fluid input side of the cell 102, and the second end 114 may be considered the fluid output side of the cell 102. In this example, the mixed fluid 110 flows from left to right from the input end 112 to the output end 114, and may be induced to do so by a suitably configured pump; other means of moving the mixed fluid 110 through the device 100 may also be employed.

[0029] The tritium extraction unit 102 also includes a second channel 116, which is separated from the first channel 108 by a hydrogen permeable membrane 118. The material for the hydrogen permeable membrane 118 is appropriately selected for a combination of volumetric strength (retaining the first fluid in the channel 108 and supporting the structure of the tritium extraction unit 102) and tritium permeability. It should also be understood that although the first channel 108, the second channel 116 and the hydrogen permeable membrane 118 are described herein as separate entities, in practice, these channels can be considered to be at least partially (or entirely) formed by the hydrogen permeable membrane, that is, the membrane 118 can be considered to form at least a portion of the upper structure or body of the tritium extraction unit 102, which defines the corresponding channels therein.

[0030] Suitably, the second channel 116 is arranged to receive tritium that permeates through the membrane 118 from the first channel. In this way, the tritium-enriched tritium breeder composition 120 at the input end 112 (i.e., directly from the breeder blanket 24) is at least partially depleted of tritium when passing through the tritium extraction unit 102. However, some tritium is absorbed by the second fluid bubbles 122. Therefore, the mixed fluid leaving the tritium extraction unit 102 can be considered to be formed by a tritium breeder composition that includes a mixture of tritium and helium-tritium gas at a low concentration (which those skilled in the art will appreciate is well suited for extraction of tritium by a suitable subsequent separation process). To this end, the second fluid 122 preferably (although not necessarily) has a higher affinity for tritium than the breeder composition 120. In particular, in the case where the tritium breeder composition 120 is formed of pure liquid lithium, the second fluid can be a molten salt (e.g., lithium chloride, a mixture of lithium and sodium or potassium chlorides, or lithium carbonate), while in the case where the tritium breeder composition 120 is formed of lead-lithium or FLiBe, the second fluid can be an inert gas, such as helium.

[0031] This two-phase flow not only allows two different extraction mechanisms to be deployed in the same device 100 , but also has benefits for the performance of the tritium extraction unit 102 in terms of permeation.

[0032] FIG. 5 illustrates these benefits in the case of ideal Taylor (two-phase) flow within the first channel 108 . Figure 5A The fluid dynamics of the tritium breeder composition 120 and the helium bubble 122 are shown; Figure 5B The tritium distribution of a channel undergoing single-phase flow is shown; Figure 5C Shows Figure 5A Example of tritium distribution.

[0033] In a single-phase flow of the breeder composition, the tritium to be extracted will be randomly (although generally uniformly) dispersed throughout the cross-section of the fluid. Tritium near the hydrogen permeable membrane 118 may permeate out very quickly based on its proximity, while the majority of tritium toward the center of the channel 108 will take significantly longer to follow the concentration gradient. Thus, at any given time, the tritium concentration follows a distribution with more tritium in the center of the channel ( Figure 5B ).

[0034] In contrast, in the case of two-phase flow, the bubbles 122 help to create a thin film of the breeder composition 120 against the permeable membrane along the portion where the bubbles are located (e.g., at portion 124), which causes the tritium to be closer to the membrane 118 and therefore more likely to permeate across the boundary. In addition, the fluid dynamics between the carrier (breeder) fluid 120 and the bubbles 122 change the flow pattern sufficiently that the tritium begins to stagnate away from the axis of the channel and so close to the side surface (i.e., the permeable membrane) that the tritium concentration profile may look like Figure 5CTherefore, the tritium permeation rate of the composition 120 between coexisting bubbles 122 is also increased.

[0035] Although FIG. 5 shows a preferred exemplary two-phase flow, similar benefits may be obtained (usually to a lesser extent) from other forms of two-phase flow, such as Figure 6 In other words, while it is preferred that the manifold and flow parameters of the first / second fluid inflows be configured to produce Taylor flow, this is not required.

[0036] Back to Figure 4 In one example, the second channel 116 is maintained at a vacuum (negative) pressure to impart a flow direction to the tritium that permeates into the channel; here, the direction is shown as from right to left, although the direction is not important and the choice will depend on physical equipment considerations at the time of use. In this way, the device 100 can be more easily used as a replacement device for fusion systems that currently utilize known PAV technology (and therefore already have suitable vacuum equipment ready to be connected to the tritium extraction unit 102). In another example, the second channel 116 is at least partially filled with a purge gas, such as helium, and the flow of the purge gas helps to make tritium flow through the tritium extraction unit 102 and be discharged from the tritium extraction unit 102, and then the tritium can be separated from the purge gas. The benefit of using a purge gas is that helium (or other gas) compressors and corresponding piping are generally cheaper than vacuum systems. In either case, the tritium that permeates into the second channel can be appropriately recovered. In some examples, the purge gas includes a very small amount of additives, such as oxygen, to help tritium desorb from the membrane surface later.

[0037] As shown, in this example, the first channel 108 and the second channel 116 are configured to extend substantially parallel to each other along the length (x direction, left / right) of the tritium extraction cell 102. Likewise, the hydrogen permeable membrane 118 provides a shared boundary between the first channel 108 and the second channel 116 along substantially the entire length of the tritium extraction cell 102. This arrangement provides an increased surface area through which tritium can permeate away from the fluid in the first channel 108.

[0038] Turning to three dimensions, more generally, the first channel 108 and the second channel 116 are preferably arranged in a planar arrangement. That is, each of the first and second channels defines parallel planes in the x (left / right) and y (into / out of the page) directions. Again, this parallel planar arrangement provides a greater surface area for tritium penetration. More preferably, the tritium extraction unit 102 in this arrangement should be mounted horizontally to the ground (i.e., perpendicular to the direction of gravity) to avoid inducing any unnecessary pumping strain on the fluid that might otherwise be caused by, for example, gravity acting on the fluid 110.

[0039] Continuing with this example, the tritium extraction unit 102 may also be considered to include a third channel 126, which is arranged on the opposite side of the second channel 116 from the first channel 108; the second and third channels are similarly separated by a hydrogen permeable membrane 118. The third channel also contains the mixed fluid 112, so that in this arrangement more surface area is provided for tritium to permeate through the hydrogen permeable membrane 118 into the second channel 116. Suitably, the manifold 104 may be adapted to supply the mixed fluid to the first and third channels, or each channel may be provided with a plurality of separate manifolds through which they are supplied with the mixed fluid.

[0040] In some examples, this principle can be further continued, with the tritium extraction unit 102 configured in a stacked arrangement, wherein mixed fluid transport channels alternate with tritium extraction channels. That is, the fourth channel can be configured to abut the third channel on the opposite side of the second channel, the fifth channel can be configured to abut the fourth channel on the opposite side of the fourth channel, and so on, with each channel generally adjacent but separated by a hydrogen permeable membrane, the odd-numbered channels being mixed fluid transport channels, and the even-numbered channels being tritium extraction channels. Or, in other words, the first and second channels 108, 116 can be considered to define the blueprint of a single stack in a stacked arrangement, with multiple stacks formed by paired first and second channels arranged on top of the third channel 126, in which case the third channel 126 can be considered to be the lowermost or bottom channel of the tritium extraction unit 102. Furthermore, while the above description assumes that the fluid transport channels being mixed will be the outermost channels of the stack (i.e., top and bottom), it will be appreciated that the arrangement could be modified to have the tritium extraction channels as the outermost channels while still achieving substantially the same functionality.

[0041] The dimensions of the first, second, and appropriately located third channels 108, 116, 126 can be determined based on the desired flow rates of the fluid / gas through the various channels. For example, in order to integrate the present device with the breeder blanket design of the DEMO power plant, it has been determined that the width of the first / third channel 108 (or each such channel in the stack) in the z direction is 0.5 centimeters (cm) to 2 cm, inclusive, producing particularly beneficial two-phase flow. Simulations also indicate that suitable tritium extraction efficiencies in excess of 80% (i.e., greater than previously achievable) can be achieved using a channel length of approximately 5 meters (m), which is much shorter than many other PAV systems, thereby reducing the overall profile of the required equipment and the corresponding space required in the power plant. In some examples, simulations show that the efficiency of a properly optimized device is between 85%-95%.

[0042] In summary, exemplary embodiments of an improved apparatus for tritium extraction and recovery have been described. The apparatus includes a manifold and a tritium extraction unit. The manifold is configured to mix a tritium breeder composition with a second fluid to produce a mixed fluid that undergoes two-phase flow. The tritium extraction unit receives the mixed fluid and simultaneously extracts tritium from the breeder composition by tritium permeation through a solid membrane and tritium transfer to the second fluid.

[0043] The described exemplary embodiments enable more efficient improved fusion power generation technology, which facilitates continuous operation of the reactor: an important consideration for commercial energy production. In addition, the exemplary embodiments reduce the energy requirements for tritium production associated with existing breeder blankets and also allow for a reduction in the tritium inventory within the plant.

[0044] The example device can be manufactured in industry. The industrial applicability of the example embodiments will become clear through the discussion herein. In addition, the described example embodiments are easy to manufacture and easy to use.

[0045] Although preferred embodiments of the present invention have been shown and described, those skilled in the art will appreciate that changes may be made without departing from the scope of the present invention as defined in the claims and as described above. For example, although channels are repeatedly mentioned herein, those skilled in the art will appreciate that channels extend to other forms of (enclosed) fluid paths, such as pipes, conduits, etc., and are not intended to impart a particular geometry unless otherwise specified for a particular example.

[0046] Please note that all papers and documents filed concurrently with or prior to this specification and related to this application are publicly available with this specification, and the contents of all these papers and documents are incorporated herein by reference.

[0047] All of the features disclosed in this specification and / or all of the steps of any method or process so disclosed may be combined in any combination, except combinations in which at least some of such features and / or steps are mutually exclusive.

[0048] Unless otherwise expressly stated, each feature disclosed in this specification can be replaced by an alternative feature used for the same, equivalent or similar purpose. Therefore, unless otherwise expressly stated, each feature disclosed is only an example of a series of equivalent or similar features.

[0049] The invention is not limited to the details of the foregoing embodiments. The invention extends to any novel one or any novel combination of features disclosed in this specification, or to any novel one or any novel combination of steps of any method or process so disclosed.

Claims

1. A device for extracting and recovering tritium in a fusion power generation system, the device comprising: a manifold configured to receive a first fluid including a tritium breeder composition and to receive a second fluid and output the mixed fluids in a two-phase flow, wherein the first fluid is a first phase or a carrier phase of the two-phase flow and the second fluid is a second phase of the two-phase flow; A tritium extraction unit is configured to receive the mixed fluid and extract tritium from the tritium breeder composition by a combination of tritium permeation through a hydrogen permeable membrane and tritium transfer to the second fluid.

2. The device according to claim 1, wherein: The second fluid includes at least one of an inert gas and a molten salt.

3. The device according to claim 1 or 2, wherein: The second fluid has a higher affinity for tritium than the first fluid.

4. The device of claims 2 and 3, wherein The tritium breeder composition is formed from pure liquid lithium and the second fluid comprises a molten salt.

5. The apparatus according to claim 4, wherein the molten salt comprises at least one of lithium chloride, lithium sodium chloride, lithium potassium chloride or lithium carbonate, or a combination thereof.

6. The device of claims 2 and 3, wherein: The tritium breeder composition is formed of a lithium-based molten salt or a lithium-based eutectic alloy, and the second fluid includes an inert gas, such as helium.

7. The apparatus according to claim 6, wherein the lithium-based molten salt is one of PbLi or FLiBe.

8. A device according to any one of the preceding claims, wherein: The tritium extraction unit includes a first channel arranged to receive the mixed fluid in two-phase flow, a second channel arranged to receive tritium from the first channel through the hydrogen permeable membrane between the first channel and the second channel.

9. The device according to claim 8, wherein: The first channel and the second channel are arranged in a planar manner.

10. The device according to claim 9, wherein: The planar arrangement is perpendicular to gravity.

11. The device according to any one of claims 8 to 10, wherein the tritium extraction unit comprises a third channel and a second hydrogen permeable membrane, the third channel is arranged on the opposite side of the second channel from the first channel, the second hydrogen permeable membrane is located between the second channel and the third channel, the third channel is further arranged to accommodate a mixed fluid in a two-phase flow, and the second channel is further arranged to receive tritium from the third channel through the second hydrogen permeable membrane.

12. The device of any preceding claim, wherein the second channel supports the flow of a purge gas.

13. The apparatus of claim 12, wherein the purge gas comprises helium.

14. A nuclear fusion power generation system, comprising: Vacuum container; a tritium breeder blanket at least partially surrounding the vacuum vessel, wherein the tritium breeder blanket comprises a fluid tritium breeder composition; a manifold configured to receive the fluid tritium breeder composition and a second fluid and output the mixed fluids in a two-phase flow, wherein the fluid tritium breeder composition is a first phase or carrier phase of the two-phase flow and the second fluid is a second phase of the two-phase flow; A tritium extraction unit is configured to receive the mixed fluid in two-phase flow and extract tritium from the breeder composition by a combination of tritium permeation through a hydrogen permeable membrane and tritium transfer to the second fluid.

15. A method for extracting tritium from a fluid tritium breeder composition, the method comprising: mixing the fluid tritium breeder composition with the second fluid to produce a mixed fluid that undergoes a two-phase flow, wherein the fluid tritium breeder composition is a first phase or carrier phase of the two-phase flow and the second fluid is a second phase of the two-phase flow; At least some tritium is extracted from the breeder composition in the two-phase flow by permeation of tritium through a hydrogen permeable membrane and at least some tritium is extracted from the breeder composition in the two-phase flow by transfer of tritium to the second fluid.

Images