Tritium shunt heat exchanger using sweep gas

Abstract

Certain aspects of the present disclosure are generally directed to tritium shunt heat exchangers that use sweep gases. In some aspects, a heat exchanger system for a fusion power plant is disclosed herein. The system advantageously enables efficient energy and tritium extraction from tritium-containing fluids while minimizing tritium leakage into the environment. For example, the system may include components such as thermally conductive solid connectors, sweep gases, and reactive materials that enable high heat transfer efficiency and / or high tritium removal and extraction efficiency. Additionally, some aspects of the present disclosure are directed to methods for using or manufacturing such systems.

Description

[Technical Field]

[0001] (Related Applications) This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 344,329, filed May 20, 2022, entitled "Tritium Shunt Heat Exchanger Using Sweep Gas," which is incorporated herein by reference in its entirety.

[0002] (Field) Certain aspects of the present disclosure are generally directed to a tritium shunt heat exchanger that uses a sweep gas. [Background technology]

[0003] (background) Fusion plants utilize the process of nuclear fusion reactions to generate electricity. The energy produced by the fusion reactions is transferred to a process fluid via a heat exchanger and subsequently utilized to generate electricity. While fusion power plants offer a promising energy source, they can produce high levels of tritium, which poses a safety concern. For example, tritium can leak into the process fluid or surrounding environment due to its high diffusivity. Current heat exchangers and other equipment lack the ability to address this issue because they are often not made to handle radioactive materials. Thus, there remains a need for more effective heat exchangers for fusion power plants that can transfer energy efficiently while ensuring minimal tritium leakage. Summary of the Invention

[0004] (overview) Certain embodiments of the present disclosure are generally directed to tritium shunt heat exchangers that use sweep gas. The subject matter of the present disclosure includes, in some cases, interrelated products, alternative solutions to a particular problem, and / or multiple different uses of one or more systems and / or articles.

[0005] One aspect of the present disclosure is generally directed to a heat exchanger system. According to one set of embodiments, the heat exchanger system includes a first conduit, a second conduit, a solid connector that thermally couples an external surface of the first conduit to an external surface of the second conduit, and a gas flow device positioned to flow gas around the first conduit, the second conduit, and the solid connector.

[0006] According to another set (or series) of embodiments, a heat exchanger system includes a first conduit containing a primary fluid, the primary fluid containing tritium; a second conduit containing a secondary fluid, the secondary fluid containing a lower concentration of tritium than the primary fluid; a solid connector thermally coupling an outer surface of the first conduit to an outer surface of the second conduit; and a sweep gas surrounding the first conduit, the second conduit, and the solid connector, the sweep gas containing tritium originating from the primary fluid.

[0007] In yet another set of embodiments, a heat exchanger system includes: a first conduit containing a primary fluid, the primary fluid including tritium; a second conduit thermally coupled to the first conduit, the second conduit containing a secondary fluid; and a reactive material disposed on the exterior of the first and second conduits to react with tritium exiting an exterior surface of the first conduit.

[0008] In yet another set of embodiments, a heat exchanger system includes: a plurality of first conduits, at least some of which contain a primary fluid, the primary fluid containing tritium; a plurality of second conduits thermally coupled to the plurality of first conduits, wherein at least one of the plurality of first conduits is thermally coupled to two or more of the plurality of second conduits and / or at least one of the plurality of second conduits is thermally coupled to two or more of the plurality of first conduits; and a sweep gas surrounding the plurality of first conduits and the plurality of second conduits, wherein the sweep gas contains tritium originating from the primary fluid.

[0009] Another aspect is generally directed to a method. In some embodiments, the method includes passing a primary fluid containing tritium through a first conduit of a heat exchanger; transferring heat from the primary fluid to a secondary fluid contained within a second conduit of the heat exchanger through a connector, the connector thermally coupling an outer surface of the first conduit to an outer surface of the second conduit; and flowing a sweep gas around the first conduit, the second conduit, and the connector to remove tritium from the primary fluid and the connector.

[0010] Another aspect is generally directed to a method of manufacturing a heat exchanger system, the method including forming a plurality of first conduits, forming at least one solid connector, forming a plurality of second conduits, and stacking the plurality of first conduits, the at least one solid connector, and the plurality of second conduits in alternating layers such that the at least one solid connector thermally couples the plurality of first conduits to the plurality of second conduits.

[0011] Other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments of the present disclosure when considered in conjunction with the accompanying figures.

[0012] BRIEF DESCRIPTION OF THE DRAWINGS Non-limiting embodiments of the present disclosure are illustratively described with reference to the accompanying drawings, which are schematic and not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown is typically represented by a single numeral. For clarity, not every component is shown in every drawing, and not every component of each embodiment of the present disclosure is shown unless illustration is necessary for those skilled in the art to understand the disclosure. In the drawings: [Brief explanation of the drawings]

[0013] [Figure 1A] FIG. 1A is a schematic representation of a side view of a heat exchanger system, according to some embodiments. [Figure 1B-1C] 1B-1C are schematic diagrams of cross-sectional views of the heat exchanger system of FIG. 1A, according to some embodiments. [Figure 2] FIG. 2 is a schematic diagram of a cross-sectional view of a heat exchanger system having a first configuration, according to some embodiments. [Figure 3] FIG. 3 is a schematic diagram of a cross-sectional view of a heat exchanger system having a second configuration, according to some embodiments. [Figure 4] FIG. 4 is a schematic diagram of a cross-sectional view of a heat exchanger system having a third configuration, according to some embodiments. [Figure 5] FIG. 5 is a schematic diagram of a cross-sectional view of a heat exchanger system having a fourth configuration, according to some embodiments. [Figure 6A] FIG. 6A is a schematic diagram of a cross-sectional view of a heat exchanger unit, according to some embodiments. [Figure 6B] FIG. 6B is a schematic illustration of a cross-sectional view of the heat exchanger unit of FIG. 6A having a coiled configuration, according to some embodiments. [Figure 6C] FIG. 6C is a schematic diagram of a side view of the heat exchanger unit of FIG. 6B, according to some embodiments. [Figure 6D] FIG. 6D is a schematic diagram of a top view of a heat exchanger system including a manifold, according to some embodiments. [Figure 7] FIG. 7 is a flow chart illustrating a method for manufacturing a heat exchanger system, according to some embodiments. [Figure 8] FIG. 8 is a flowchart illustrating a method of using a heat exchanger system, according to some embodiments. [Figure 9] FIG. 9 is a schematic diagram of a fusion power plant including a heat exchanger system, according to some embodiments. [Figures 10A-10B] 10A-10B are schematic diagrams of cross-sectional views of heat exchanger systems including alternating layers of tubes and copper plates, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0014] (Detailed explanation) Certain aspects of the present disclosure are generally directed to tritium shunt heat exchangers that use sweep gas. In some aspects, a heat exchanger system for a fusion power plant is disclosed herein. The system may advantageously enable efficient energy and tritium extraction from a tritium-bearing fluid while minimizing tritium leakage into the environment. For example, the system may include components such as thermally conductive solid connectors, sweep gas, reactive materials, etc. that enable high heat transfer efficiency and / or high tritium removal and extraction efficiency. Additionally, some aspects of the present disclosure are directed to methods for using or manufacturing such systems.

[0015] For example, some aspects of the present disclosure are generally directed to heat exchange systems in which it is desired to transfer heat from a primary fluid containing (or carrying) radioactive tritium to a secondary fluid without transferring a substantial amount of tritium to the secondary fluid (which could create problems in terms of the subsequent disposal of the secondary fluid if it also becomes radioactive). For example, the primary fluid may capture neutrons and convert them into tritium in lithium salts. 6 Li 3 H or T (tritium) and 4 It can be molten lithium salts used to convert it to He (helium).

[0016] As previously mentioned, tritium is an isotope of hydrogen and is radioactive; however, unlike most other substances, its extremely small size (as a hydrogen atom) allows it to diffuse very quickly through most materials. Thus, tritium can easily diffuse through materials containing the primary fluid or used to form the heat transfer connector, such as iron or stainless steel. Therefore, while the heat transfer connector can be used as a conduit to transfer heat between the primary and secondary fluids, tritium can also diffuse from the primary fluid through the solid connector and into the secondary fluid, rendering the secondary fluid unacceptably radioactive. Separating the primary and secondary fluids by a longer distance, for example, by using a longer connector, can reduce the amount of tritium diffusion. However, doing so not only reduces the amount of tritium that can transfer between the primary and secondary fluids, but can also reduce the amount of heat transferred. Therefore, a system is needed that can transfer heat while minimizing tritium transfer.

[0017] Thus, the various heat exchanger systems described herein may, in certain embodiments, enable the efficient recovery of energy from a primary fluid, including energy released from a fusion reaction (e.g., including thermal energy from captured neutrons and energy containing tritium). In some cases, the heat exchanger system is designed to direct tritium away from a heat connector that thermally couples a first conduit containing the primary fluid to a second conduit containing the secondary fluid by forming a "sink" for removing tritium, for example, with a sweep gas flowing around the connector and / or one or more reactive materials that can react with tritium, for example, by reacting the tritium to form water, ammonia, methane, or other substances.

[0018] For example, a heat exchanger system may include components and / or have a particular configuration that allows for utilizing the energy generated from the fusion reaction while preventing or minimizing energy loss due to waste heat loss. In one embodiment, the heat exchanger system may include thermally conductive solid connectors that couple various heat exchanger conduits (e.g., first and second conduits) containing a primary fluid (e.g., a fluid containing molten lithium and tritium) and a secondary fluid (e.g., a process fluid such as water). The solid connectors may have a particular configuration and / or properties that allow for efficient heat transfer.

[0019] Additionally, in certain embodiments, the heat exchanger system may prevent or reduce tritium leakage from the heat exchanger. As previously mentioned, tritium has a surprisingly high diffusivity due to its small size, allowing it to diffuse through and diffuse relatively quickly through many materials. Thus, for example, the heat exchanger system may include various configurations and / or components that facilitate heat recovery while reducing or minimizing tritium leakage. For example, in certain embodiments, the heat exchanger system may include a tritium sink, such as a sweep gas (e.g., air, nitrogen, carbon dioxide, etc.) and / or a reactive material (e.g., a material capable of reacting with tritium), that can remove at least some of the tritium that escapes or escapes from the primary fluid, e.g., such that a small or negligible amount of tritium from the primary fluid leaks into the secondary fluid. Additionally or alternatively, in some embodiments, the various heat exchanger conduits and connectors may be arranged in particularly beneficial configurations, e.g., alternating layers, that provide the heat exchanger system with enhanced heat transfer and / or tritium removal capabilities.

[0020] In some embodiments, the heat exchanger system may be particularly useful in fusion power plants, such as tokamaks, for example, for the extraction and recycling of tritium. 2 H) and tritium ( 3 H or T) nuclear fusion reaction, and neutrons ( 1n) and helium (He). Significant energy produced from the fusion reaction is available in the form of kinetic energy of neutrons. To ensure an adequate supply of tritium, it may be beneficial to generate additional tritium from the neutrons and recycle it, for example, for use within the fusion reaction. For example, neutrons (e.g., see Equation (1)) may be sent to a fluid containing lithium, where they may participate in the reaction to generate additional tritium (e.g., see Equation (2)). The generated tritium may be recycled back into the deuterium-tritium fusion reaction to generate additional neutrons. During this process, the energy associated with the neutrons may be converted to thermal energy, which may be utilized by the heat exchanger system described herein.

[0021] [ka] [ka]

[0022] In some embodiments involving nuclear fusion reactions (e.g., the reactions shown in Equations (1)-(2)), in addition to utilizing energy from the fusion reaction and minimizing tritium leakage, the heat exchanger systems may have one or more advantages over conventional heat exchanger systems. For example, the heat exchanger systems described herein may aid in the extraction and recycling of tritium for use in subsequent fusion reactions.

[0023] While various embodiments herein are described as using heat exchanger systems in nuclear fusion plants, it should be understood that the disclosure is not so limited and that in certain cases heat exchanger systems may be used in any of a variety of suitable power plants, chemical plants, etc. to recover heat generated from suitable types of reactions.

[0024] Thus, certain aspects discussed herein are generally directed to heat exchangers having heat transfer conduits or connectors between a first conduit containing a primary fluid containing tritium and a second conduit containing a secondary fluid that allow heat transfer from the primary fluid to the secondary fluid but minimize or reduce the amount of tritium that exits the primary fluid (i.e., due to its high diffusivity and small size) and enters the secondary fluid. As discussed herein, various embodiments are used to create a tritium sink to minimize the ability of tritium to reach the secondary fluid. For example, in one embodiment, a sweep gas may be used to remove tritium that diffuses out, e.g., in the connector. In another embodiment, a reactive material may be used to react with tritium. The reactive material may be present on the conduit, in the connector, on the connector, in the sweep gas, etc.

[0025] In some embodiments, the connector (e.g., a solid connector) is constructed and arranged so that a substantial amount of the tritium leaving the primary fluid diffuses into the sweep gas before reaching the secondary fluid. For example, in some cases, at least 50% (e.g., at least 55%, at least 60%, at least 70%, at least 80%, at least 85%, at least 90%, at least 92.5%, at least 95%, at least 97.5%, at least 99%, at least 99.5%, at least 99.9%, at least 99.95%, at least 99.99%, or all) of the tritium leaving the primary fluid diffuses into the sweep gas before reaching the secondary fluid. As described in more detail below, in certain embodiments, the solid connector may have particularly advantageous dimensions, material properties (e.g., permeability to tritium, tritium diffusivity, etc.) and / or configuration, e.g., a configuration such that a substantial amount of the tritium leaving the primary fluid diffuses into the sweep gas.

[0026] The solid connector may comprise any of a variety of suitable materials. In some cases, the solid connector may comprise a material having a thermal conductivity, tritium permeability, and / or ratio of thermal conductivity to tritium permeability within one or more ranges described herein. In certain cases, the solid connector may have a relatively low tritium permeability. In some embodiments, the solid connector may comprise, for example, a conductive metal or metal alloy. By way of non-limiting example, metals and / or metal alloys used in the solid connector may include copper, nickel, tungsten, molybdenum, copper alloys, nickel alloys, nickel-chromium alloys, nickel-copper alloys, iron-nickel-chromium alloys (e.g., stainless steel), and any combination of these and / or other metals. However, it should be understood that other thermally conductive materials may also be used, provided that the material has an appropriate thermal conductivity, tritium permeability, and / or ratio of thermal conductivity to tritium permeability within one or more ranges described herein.

[0027] The connectors (e.g., solid connectors) described herein can have any of a variety of suitable dimensions. For example, in some cases, the connector can have a specific ratio of external surface area to cross-sectional area. For example, as shown in FIGS. 1A-6, the connector can have an exterior surface exposed to the sweep gas. The connector can also have a cross-section perpendicular to the direction in which the connector extends from the first conduit to the second conduit. In some embodiments, the ratio of the external surface area to cross-sectional area of the connector is at least 0.5, at least 1, at least 1.5, at least 2, at least 4, at least 6, or at least 8. In some embodiments, the ratio of the external surface area to cross-sectional area of the connector is 10 or less, 8 or less, 6 or less, 4 or less, 2 or less, 1.5 or less, or 1 or less. Any of the above ranges are possible (e.g., at least 0.5 and 10 or less). Other ranges are also possible.

[0028] The connectors can have any of the various shapes and configurations described herein. In some examples, the connectors can have a flat sheet shape, for example, as shown in Figures 5-6. In other examples, the connectors can have a corrugated sheet shape, as shown in Figures 3-4. Other shapes and configurations are possible.

[0029] The connectors (e.g., solid connectors) described herein can have any of a variety of suitable thermal conductivity values. In some embodiments, the solid connectors have relatively high thermal conductivity. In some embodiments, the solid connectors have a thermal conductivity of at least 10 W m at temperatures between 700 K and 900 K (e.g., about 800 K, about 850 K, etc.). -1 K -1 , at least 20W m -1 K -1 , at least 30W m -1 K -1 , at least 40W m -1 K -1 , at least 50W m -1 K -1 , at least 60W m -1 K -1 , at least 80W m -1 K -1 , at least 100W m -1 K -1 , at least 150W m -1 K -1 , at least 200W m -1 K -1 , at least 250W m -1 K -1 , at least 300W m -1 K -1 , at least 350W m -1 K -1 , or at least 380W m -1 K -1 In some embodiments, the connector (e.g., a solid connector) may have a thermal conductivity of 400 W m at a temperature of 700 K to 900 K (e.g., about 800 K, about 850 K, etc.). -1 K-1 Below, 380W m -1 K -1 Below, 350W m -1 K -1 Below, 300W m -1 K -1 Below, 250W m -1 K -1 Below, 200W m -1 K -1 Below, 150W m -1 K -1 Below, 100W m -1 K -1 Below, 80W m -1 K -1 Below, 60W m -1 K -1 At least 50W m -1 K -1 At least 40W m -1 K -1 Below, 30W m -1 K -1 or less than 20W m -1 K -1 Combinations of the above ranges are also possible (at least 20 W m -1 K -1 or more and 380W m -1 K -1 Other ranges are possible.

[0030] In some embodiments, the solid connector can have any of a variety of suitable permeabilities to tritium. In some embodiments, the solid connector has a relatively low tritium permeability, e.g., such that little, if any, tritium permeates through the solid connector from the primary fluid to the secondary fluid. The solid connector can be, for example, 10°C at temperatures between 700K and 900K (e.g., about 800K, about 850K, etc.). -5 mole m -1 s -1 MPa -1 / 2 Below, 10 -6 mole m -1 s -1 MPa -1 / 2 Below, 10-7 mole m -1 s -1 MPa -1 / 2 Below, 10 -8 mole m -1 s -1 MPa -1 / 2 Below, 10 -9 mole m -1 s -1 MPa -1 / 2 Below, 10 -10 mole m -1 s -1 ·MPa -1 / 2 Below, 10 -11 mole m -1 s -1 MPa -1 / 2 Below, 10 -12 mole m -1 s -1 MPa -1 / 2 Below, 10 -14 mole m -1 s -1 MPa -1 / 2 Less than or equal to 10 -16 mole m -1 s -1 MPa -1 / 2 In some embodiments, the solid connector may have a tritium permeability of at least 10 at a temperature of 700 K to 900 K (e.g., about 800 K or 800 K, about 850 K or 850 K, etc.). -20 mole m -1 s -1 MPa -1 / 2 , at least 10 -16 mole m -1 s -1 MPa -1 / 2 , at least 10 -14 mole m -1 s -1 MPa -1 / 2 , at least 10 -12 mole m -1 s -1 MPa -1 / 2 , at least 10 -11 mole m -1 s -1 MPa -1 / 2 , at least 10 -10 mole m -1 s -1 MPa-1 / 2 , at least 10 -9 mole m -1 s -1 MPa -1 / 2 , at least 10 -8 mole m -1 s -1 MPa -1 / 2 , at least 10 -7 mole m -1 s -1 MPa -1 / 2 , or at least 10 -6 mole m -1 s -1 MPa -1 / 2 Any of the above ranges is possible (e.g., at least 10 -20 mole m -1 s -1 MPa -1 / 2 Katsu 10 -6 mole m -1 s -1 MPa -1 / 2 Other ranges are possible. In one set of embodiments, the solid connector is -6 mole m -1 s -1 MPa -1 / 2 It has the following permeability to tritium:

[0031] The solid connectors described herein can have any of a variety of suitable ratios of thermal conductivity to tritium permeability. In some cases, the solid connectors can have a relatively high ratio of thermal conductivity to tritium permeability. A solid connector having a relatively high ratio of thermal conductivity to tritium permeability can, for example, allow efficient heat transfer from the primary fluid to the secondary fluid while minimizing tritium permeation across the solid connector. In some embodiments, the solid connector can have a thermal conductivity of at least 1000 kJ / cm2 at temperatures between 700 K and 900 K (e.g., about 800 K, about 850 K, etc.). 10 N 3 / 2 mole -1 K -1 , at least 2 10 10 N 3 / 2 mole -1 K-1 , at least 5 10 10 N 3 / 2 mole -1 K -1 , at least 10 11 N 3 / 2 mole -1 K -1 , at least 2 10 11 N 3 / 2 mole -1 K -1 , at least 4 10 11 N 3 / 2 mole -1 K -1 , at least 10 12 N 3 / 2 mole -1 K -1 , at least 10 14 N 3 / 2 mole -1 K -1 , at least 10 16 N 3 / 2 mole -1 K -1 , or at least 10 18 N 3 / 2 mole -1 K -1 In some embodiments, the solid connector may have a ratio of thermal conductivity to tritium permeability of up to 10 at temperatures between 700 K and 900 K (e.g., about 800 K, about 850 K, etc.). 11 N 3 / 2 mole -1 K -1 , up to 2 10 11 N 3 / 2 mole -1 K -1 , up to 4 10 11 N 3 / 2 mole -1 K -1 , up to 10 12 N 3 / 2 mole -1 K -1 , up to 10 14 N 3 / 2 mole -1 K -1 , up to 10 16 N 3 / 2 mole -1 K -1, up to 10 18 N 3 / 2 mole -1 K -1 , up to 10 20 N 3 / 2 mole -1 K -1 , or up to 10 21 N 3 / 2 mole -1 K -1 Combinations of the above ranges are also possible (at least 2 10 10 N 3 / 2 mole -1 K -1 and a maximum of 10 21 N 3 / 2 mole -1 K -1 ). Other ranges are possible.

[0032] Thus, in some embodiments, the method includes transferring heat from the primary fluid to a secondary fluid contained within a second conduit of the heat exchanger through a connector. For example, as described herein, a heat exchanger system may include a connector (e.g., a solid connector) that thermally couples an outer surface of the first conduit to an outer surface of the second conduit.

[0033] 1A-6D, for example, in a heat exchanger system (e.g., systems 10, 30, 50, 60, 70, 80), heat may be conducted (or directed) from a primary fluid (e.g., fluid 13) contained in a first conduit (e.g., conduit 12, 32, 52, 62, 72, 82) to a secondary fluid (e.g., fluid 15) contained in a second conduit (e.g., second conduit 14, 34, 54, 64, 74, 84) via a connector (e.g., connector 16, 36, 56, 66, 76, 86).

[0034] In some embodiments, the heated secondary fluid exits the heat exchanger system into the environment and may then be used in various power turbines and / or generators to generate electricity, non-limiting examples of which include steam turbines, supercritical carbon dioxide turbines, etc.

[0035] Tritium exiting the exterior surface of the first conduit may be removed by the sweep gas in any suitable manner, according to one set of embodiments. For example, tritium may be removed by physical forces and / or chemical reactions, etc.

[0036] In some embodiments, tritium from the primary fluid may be removed with a sweep gas via physical forces (e.g., forced advection, etc.). In some embodiments, the sweep gas may have any suitable flow rate, tritium partial pressure, etc. that facilitates removal of tritium exiting the first conduit. For example, in one set of embodiments, the sweep gas may have a relatively low tritium partial pressure, e.g., such that the sweep gas acts as a tritium sink and promotes diffusion of tritium into the sweep gas. Alternatively or additionally, the sweep gas may have a relatively high flow rate, e.g., such that tritium exiting the exterior surface of the first conduit is advected away from the surface of the first conduit. In some embodiments, the sweep gas may include an inert gas, e.g., a gas that is inert (e.g., non-reactive) in the presence of tritium. Non-limiting examples of inert gases may include helium, argon, neon, krypton, etc. In yet other embodiments, the sweep gas may include air. In still other embodiments, the sweep gas may include nitrogen, carbon dioxide, oxygen, etc. Such sweep gases need not react with tritium, but in some embodiments can act as a physical technique for removing tritium.

[0037] Thus, in some embodiments, the method includes flowing a sweep gas around the first conduit, the second conduit, and the connector to remove tritium from the primary fluid and the connector. In some embodiments, the sweep gas may facilitate removal of tritium from the primary fluid and the connector as tritium from the primary fluid exits through the exterior surface of the first conduit and / or the connector. Without wishing to be bound by theory, the sweep gas may substantially reduce the amount of tritium permeable to the secondary fluid contained within the second conduit by facilitating removal of tritium from the primary fluid and the connector, e.g., by creating a tritium "sink" away from the connector.

[0038] 1A-6D, a heat exchanger (e.g., systems 10, 30, 50, 60, 70, 80) can include a sweep gas (e.g., gas 20). As tritium from the primary fluid exits and / or permeates through the first conduits and / or connectors (e.g., as indicated by flow arrows 19), the sweep gas can facilitate removal of the escaping tritium. In some examples, a sweep gas (e.g., gas 20) may flow around the first conduit (e.g., first conduit 12, 32, 52, 62, 72, 82), the second conduit (e.g., second conduit 14, 34, 54, 64, 74, 84) and the connector (e.g., connector 16, 36, 56, 66, 76, 86) to remove tritium from the primary fluid (e.g., fluid 13) and the connector (e.g., connector 16, 36, 56, 66, 76, 86).

[0039] In some embodiments, the sweep gas may remove a significant amount of tritium that exits (e.g., permeates) from the exterior surface of the first conduit. For example, referring back to Figures 1A-6D, a significant amount of tritium that exits the exterior surface (e.g., surfaces 12A, 32A, 52A, 62A, 72A, 82A) of a first conduit (e.g., first conduit 12, 32, 52, 62, 72, 82) may be removed by the surrounding sweep gas (e.g., gas 20), as shown by flow arrow 19. In some examples, at least 50% (e.g., at least 55%, at least 60%, at least 70%, at least 80%, at least 85%, at least 90%, at least 92.5%, at least 95%, at least 97.5%, at least 99%, at least 99.5%, at least 99.9%, at least 99.95%, at least 99.99%, or all) of the tritium (by mass) exiting (e.g., permeating) the exterior surface of the first conduit can be removed by the sweep gas. In one set of embodiments, the sweep gas can remove at least 90% by mass of the tritium exiting (e.g., permeating) the exterior surface of the first conduit.

[0040] In some embodiments, the sweep gas may include an inert gas (e.g., a gas that is not reactive with tritium) and / or a reactive gas (e.g., a gas that reacts with tritium to form a tritium-containing reaction product). In some embodiments, the sweep gas may further be associated with a reactive solid or solid catalyst contained within the space in which the sweep gas resides. The solid catalyst may, in some cases, facilitate a reaction between the reactive gas and tritium exiting the exterior surface of the first conduit. Non-limiting examples of solid catalysts include various noble metals (e.g., platinum, palladium, silver, etc.) and / or metal oxides (e.g., CuO, NiO, Co3O4, MnO2, etc.). In some embodiments, the sweep (or sweep) includes a gas having a relatively low thermal conductivity.

[0041] In some embodiments, the sweep gas described herein may have a particular set of properties, e.g., flow rate, tritium partial pressure, reactivity with tritium, etc., such that it may remove a significant amount of tritium exiting the exterior surface of the first conduit and / or connector. For example, in one set of embodiments, at least 50% (e.g., at least 55%, at least 60%, at least 70%, at least 80%, at least 85%, at least 90%, at least 92.5%, at least 95%, at least 97.5%, at least 99%, at least 99.5%, at least 99.9%, at least 99.95%, at least 99.99%, or all) of the tritium exiting (e.g., permeating) the exterior surface of the first conduit may be removed by the sweep gas.

[0042] In some embodiments, the sweep gas may have a relatively high flow rate. In some embodiments, the sweep gas may have a flow rate of at least 0.01 m per megawatt. 3 / s, at least 0.1m per megawatt 3 / s, at least 1 m per megawatt 3 / s, at least 10m per megawatt 3 / s, at least 50m per megawatt 3 / s, at least 100m per megawatt 3 / s, at least 200m per megawatt 3 / s, at least 400m per megawatt 3 / s, at least 600m per megawatt 3 / s, or at least 800m per megawatt 3 / s of heat exchange capacity. In some embodiments, the sweep gas may have a flow rate of 1000 m3 / megawatt. 3 / s or less, 800m per megawatt 3 / s or less, 600m per megawatt 3 / s or less, 400m per megawatt 3 / s or less, 200m per megawatt 3 / s or less, 100m per megawatt 3 / s or less, 50m per megawatt3 / s or less, 10m per megawatt 3 / s or less, 1m per megawatt 3 / s or less, or 0.1m per megawatt 3 / s or less. Combinations of the above ranges are also possible (e.g., at least 0.01 m per megawatt). 3 / s and 1000m 3 / s or less heat exchange capacity). Other ranges are possible.

[0043] In some embodiments, the sweep gas can have any suitable partial pressure of tritium. In some embodiments, the sweep gas can have a relatively low tritium partial pressure. In some embodiments, the sweep gas can have a pressure of 100 Pa or less, 50 Pa or less, 10 Pa or less, 5 Pa or less, 1 Pa or less, 0.5 Pa or less, 0.1 Pa or less, 0.05 Pa or less, 10 -2 Pa or less, 10 -3 Pa or less, 10 -4 Pa or less, 10 -5 Pa or less, 10 -6 Pa or less, 10 -7 Pa or less, 10 -8 Pa or less, or 10 -9 In some embodiments, the sweep gas may have a tritium partial pressure of 10 Pa or less. -10 Pa or above, 10 -9 Pa or above, 10 -8 Pa or above, 10 -7 Pa or above, 10 -6 Pa or above, 10 -5 Pa or above, 10 -4 Pa or above, 10 -3 Pa or above, 10 -2 The tritium partial pressure may be greater than or equal to 0.05 Pa, greater than or equal to 0.1 Pa, greater than or equal to 0.5 Pa, greater than or equal to 1 Pa, greater than or equal to 5 Pa, greater than or equal to 10 Pa, or greater than or equal to 50 Pa. Combinations of the above ranges are also possible (e.g., 10 -10 Other ranges are possible. For example, in some embodiments, the sweep gas may be 10 -5 The tritium partial pressure may be less than or equal to 1 Pa.

[0044] In some embodiments, tritium from the primary fluid may be removed by the sweep gas via a chemical route (e.g., chemical reaction). For example, the sweep gas may have some reactivity with tritium, such that at least a portion of the tritium exiting the exterior surface of the first conduit may be removed (e.g., reactively removed) by reactive materials within and / or associated with the sweep gas. For example, in one set of embodiments, the sweep gas may include a reactive gas capable of reacting with (e.g., chemically bonding with) tritium. Non-limiting examples of reactive gases include oxygen, carbon dioxide, nitrogen, chlorine, fluorine, etc. In some embodiments, the reactive gas may react with tritium to form one or more tritium-containing reaction products. For example, in one embodiment, oxygen may react with tritium to form water (i.e., tritiated water). As another example, nitrogen may react with tritium to form ammonia (i.e., tritiated ammonia). In some embodiments, such reactions may occur under reducing conditions (e.g., to promote the hydrogenation of a reactive gas, such as nitrogen or carbon, with hydrogen, i.e., tritium).

[0045] The tritium-containing reaction product may be present in any suitable form, for example, as a liquid, gas, and / or solid. Non-limiting examples of tritium-containing reaction products may include, but are not limited to, tritiated water (HTO or TO), tritiated ammonia (NHT, NHT, NT), tritiated methane (CHT, CHT, CHT, CT), tritiated hydrogen chloride (TCl), tritiated hydrogen fluoride (TF), etc. It should be noted that the sweep gas may include any of the various types of gases mentioned above, e.g., inert and / or reactive gases, to facilitate removal of tritium from the exterior surface of the first conduit.

[0046] 1-6 illustrate various embodiments of a heat exchanger system including a sweep gas configured to remove tritium, it should be noted that the disclosure is not so limited, and in other embodiments, the heat exchanger system may additionally or alternatively include one or more reactive materials configured to remove tritium. The one or more reactive materials may be disposed in any suitable location within the heat exchanger system.

[0047] For example, in one set of embodiments, the heat exchanger system may include one or more reactive materials, e.g., reactive solids and / or reactive liquids, configured to remove (e.g., reactively remove) tritium from the surface of the first conduit. For example, in one set of embodiments, the reactive solids and / or reactive liquids may be disposed within a space external to the first conduit, the second conduit, and / or the connector. In some embodiments, the heat exchanger system, in addition to containing a sweep gas, may include one or more reactive solids or liquids disposed within the space containing the sweep gas. The one or more reactive solids or liquids may participate in one or more reactions with tritium to form any of the various tritium-containing reaction products described elsewhere herein. The one or more reactive solids or liquids may include various reactants and / or catalysts described herein. A non-limiting example of a reactive solid is copper(II) oxide (CuO), a solid reactant that can react with tritium to form, for example, tritiated water (HTO or TO). Further examples of various types of solid reactive materials may include iron oxides (e.g., hematite (Fe2O3), magnetite (Fe3O4), etc.), nickel oxide, chromium oxide, titanium, cerium, lanthanum, barium, zirconium, activated carbon, zeolites, etc. In some embodiments where the reactive material is a solid, non-limiting examples of tritium-containing reaction products include tritiated water, tritiated ammonia, tritiated methane, tritium chloride, metal hydrides, etc. In some embodiments, the reactive solid may be capable of absorbing and / or binding tritium to active sites present on its surface.

[0048] Alternatively or additionally, the heat exchange system may include a reactive coating on an exterior surface of the first conduit and / or connector. The reactive coating may include one or more reactive materials (e.g., reactive solids described herein) capable of reacting with tritium to form one or more tritium-containing reaction products described elsewhere herein.

[0049] As noted above, in some embodiments, when tritium from the primary fluid exits the exterior surface of the first conduit, it may react with reactive solids, liquids, and / or gases disposed outside the first conduit to form one or more tritium-containing reaction products. The reactive solids, liquids, and / or gases may include any of the various solids, liquids, and / or gases described above and may be disposed in any suitable location (e.g., as a coating on the first conduit and / or connector, contained within (spacing including)) a sweep gas, etc.).

[0050] In some embodiments, the method includes extracting the removed tritium from the sweep gas and / or tritium-containing reaction products formed in the heat exchanger system. In some embodiments, the removed tritium and / or tritium-containing reaction products exiting the heat exchanger system may be passed to a tritium extractor or separator. The tritium may be extracted via any of a variety of processes, including, but not limited to, temperature swing, pressure swing, electrolytic processes, and / or isotope separation processes.

[0051] In some embodiments, the extracted tritium may be recycled to the fusion plant for subsequent use. For example, in some embodiments, the tritium may then be recycled to the reactor as a reactive material for carrying out additional fusion reactions (e.g., as illustrated in equation (1) above).

[0052] As noted above, the heat exchanger system, in some embodiments, can include any of a variety of reactive materials disposed external to the first conduit. For example, the reactive material can be present on the surface of the conduit (e.g., the first conduit or the second conduit) and / or in the sweep gas (if present).

[0053] The reactive material may, in some cases, be capable of removing (e.g., reacting away) at least 50% (e.g., at least 55%, at least 60%, at least 70%, at least 80%, at least 85%, at least 90%, at least 92.5%, at least 95%, at least 97.5%, at least 99%, at least 99.5%, at least 99.9%, at least 99.95%, at least 99.99%, or all) of the tritium. As described elsewhere herein, non-limiting examples of reactive materials include reactive solids (e.g., CuO, etc.), solid catalysts, reactive liquids, reactive gases (e.g., O, CO, N, etc.), reactive coatings, or combinations thereof. In one set of embodiments, the heat exchanger system may include both a reactive material and a sweep gas. In another set of embodiments, the heat exchanger system includes a reactive material but lacks a sweep gas.

[0054] For example, in some embodiments, the heat exchanger systems described herein can include a coating applied to one or more surfaces within the heat exchanger system. For example, the coating can advantageously reduce tritium permeation, mitigate corrosion of surfaces in contact with the fluid, and / or react with tritium. For example, in one set of embodiments, a tritium-resistant coating can be applied to the exterior surface of the second conduit to prevent tritium from permeating into the secondary fluid contained within the second conduit. Non-limiting examples of tritium-resistant coatings include tungsten, aluminum oxide, yttrium oxide, titanium nitride, boron nitride, aluminum nitride, silicon carbide, etc.

[0055] In some embodiments, a reactive coating may be applied to the exterior surface of the first conduit, as described elsewhere herein. The reactive coating may, in some cases, include a reactive solid capable of reacting with tritium exiting the exterior surface of the first conduit to form a tritium-containing reaction product. Non-limiting examples of reactive solid coatings include CuO, iron oxides (e.g., hematite (FeO), magnetite (FeO), etc.), nickel oxide, chromium oxide, titanium, cerium, lanthanum, barium, zirconium, activated carbon, zeolites, etc. Alternatively or additionally, the reactive coating may include a catalyst capable of catalyzing the reaction between the exiting tritium and the reactive material described herein. Non-limiting examples of catalysts that may be used in the coating include noble metals (e.g., palladium, platinum, silver, etc.) and / or metal oxides (e.g., CuO, NiO, CoO, MnO, etc.). The presence of one or more coatings described herein advantageously assists in the removal of exiting tritium from the primary fluid and prevents permeation of the exiting tritium into the secondary fluid.

[0056] As described above, the primary fluid within the heat exchanger system may be a tritium-containing fluid. In some embodiments, the primary fluid entering the inlet of the first conduit may have a higher tritium concentration than the primary fluid exiting the outlet of the first conduit. For example, the presence of a sweep gas and / or reactive material within the heat exchanger system may remove a significant amount of tritium from the primary fluid entering the first conduit, thereby producing an outlet primary fluid stream having a lower tritium concentration.

[0057] The primary fluid entering the first conduit of the heat exchanger system can contain any of various amounts or concentrations of tritium. In some embodiments, the primary fluid contains at least 10 -6 moles / m 3 , at least 10 -5 moles / m 3 , at least 10 -4 moles / m 3, at least 10 -3 moles / m 3 , at least 10 -2 moles / m 3 , at least 10 -1 moles / m 3 , at least 1 mol / m 3 , or at least 5 moles / m 3 In some embodiments, the primary fluid may contain up to 10 -5 moles / m 3 , up to 10 -4 moles / m 3 , up to 10 -3 moles / m 3 , up to 10 -2 moles / m 3 , up to 10 -1 moles / m 3 , up to 1 mol / m 3 , up to 5 mol / m 3 , or up to 10 moles / m 3 Combinations of the above ranges are possible (e.g., at least 10 -6 moles / m 3 of tritium (i.e., 0.03 Ci m -3 of tritium activity (or radioactivity) and up to 10 moles / m 3 of tritium (i.e., 290,000 Ci m -3 (This corresponds to a tritium activity of 1000 kJ / L). Other ranges are possible.

[0058] In some embodiments, the primary fluid exiting the first conduit of the heat exchanger may contain an amount (e.g., molar %) of tritium that is less than the tritium concentration in the primary fluid entering the first conduit, which is at least 50% (e.g., at least 60%, at least 70%, at least 80%, at least 85%, at least 90%, at least 92.5%, at least 95%, at least 97.5%, at least 99%, at least 99.5%, at least 99.9%, at least 99.95%, at least 99.99%, etc.). In some examples, the primary fluid exiting the first conduit contains negligible or no tritium.

[0059] The primary fluid entering the heat exchanger can have any of a variety of suitable inlet temperatures. In some embodiments, the primary fluid entering the heat exchanger can have an inlet temperature of 600 K or more, 650 K or more, 700 K or more, 750 K or more, 800 K or more, 850 K or more, 900 K or more, or 1000 K or more. In some embodiments, the primary fluid entering the heat exchanger system can have an inlet temperature of 1200 K or less, 1100 K or less, 1000 K or less, 900 K or less, 850 K or less, 800 K or less, 750 K or less, 700 K or less, or 600 K or less. Combinations of the above ranges are possible (e.g., 600 K or more and 1200 K or less). Other ranges are also possible.

[0060] In some embodiments where the heat exchanger is used in a fusion power plant, the primary fluid includes a lithium-containing material. The lithium-containing material may be a tritium breeder material. For example, the lithium-containing material may be capable of reacting with neutrons produced from the fusion reaction to produce additional tritium. See, e.g., Equation (2).

[0061] Lithium-containing materials can include, for example, lithium-containing liquid metals, lithium-containing liquid metal alloys, lithium-containing molten salts, etc. Non-limiting examples of molten salts containing lithium include FLiBe, FLiNaK, FLiNaBe, LiF-PbF2 mixtures, etc. Non-limiting examples of liquid metals and metal alloys containing lithium include Li, Pb-Li, etc.

[0062] Additionally or alternatively, in some embodiments in which the heat exchanger is used in a fusion power plant, the lithium-containing material may advantageously comprise a neutron multiplying material. Non-limiting examples of neutron multiplying materials include one or more of beryllium, lead, metallic beryllium and its alloys, metallic lead and its alloys, etc. Non-limiting examples of lithium-containing materials (e.g., molten salts and / or liquid metals) that comprise neutron multiplying materials include FLiBe, Pb—Li, FLiNaBe, LiF—PbF mixtures, etc.

[0063] In some embodiments where the heat exchanger is used in a nuclear fission power plant, the primary fluid may comprise any of a variety of suitable materials. In some embodiments, the primary fluid may comprise a material having a particular set of thermal, hydraulic, and / or neutronic properties suitable for use in a heat exchanger used in a nuclear fission power plant. In one embodiment, the primary fluid may comprise a lithium-containing material described elsewhere herein. In another set of embodiments, the primary fluid may comprise a non-lithium-containing material. Non-limiting examples of materials for use as primary fluids in heat exchangers in nuclear fission power plants include light water (e.g., 1 H), heavy water (e.g. 2 H), FLiBe, FLiNaK, FLiNaBe, NaF-NaBF4, KF-ZrF4, etc.

[0064] In certain embodiments, the secondary fluid entering the second conduit may contain negligible amounts of tritium, if any. -7 moles / m 3 Less than or equal to (e.g., 10 -8 moles / m 3 Below, 10 -9 moles / m 3 Below, 10 -10 moles / m 3 Below, 10 -11 moles / m 3 Below, 10 -12 moles / m 3 Below, 10 -15 moles / m 3 Below, 10 -20 moles / m 3 In some embodiments, the secondary fluid does not contain any tritium (e.g., tritium is present at 0 mole m or less of the secondary fluid entering the second conduit of the heat exchanger system). 3 (configure).

[0065] The secondary fluid entering the heat exchanger can have any of a variety of suitable fluid temperatures. In some embodiments, the secondary fluid entering the heat exchanger can have a temperature of 300 K or more, 400 K or more, 500 K or more, 600 K or more, 700 K or more, 800 K or more, or 850 K or more. In some embodiments, the secondary fluid entering the heat exchanger system can have a temperature of 900 K or less, 850 K or less, 800 K or less, 700 K or less, 600 K or less, 500 K or less, or 400 K or less. Combinations of the above ranges are also possible (e.g., 300 K or more and 900 K or less). Other ranges are also possible.

[0066] In some embodiments, the secondary fluid exiting the second conduit of the heat exchanger may contain a relatively small (or negligible) amount of tritium. The heat exchanger systems described herein may advantageously prevent tritium in the primary fluid from leaking into the secondary fluid. In some embodiments, the secondary fluid exiting the second conduit may contain less than 10 -7 moles / m 3 Less than or equal to (e.g., 10 -8 moles / m 3 Below, 10 -9 moles / m 3 Below, 10 -10 moles / m 3 Below, 10 -11 moles / m 3 Below, 10 -12 moles / m 3 Below, 10 -15 moles / m 3 Below, 10 -20 moles / m 3 In some embodiments, the secondary fluid does not contain any tritium (e.g., tritium is present at 0 mole m of the secondary fluid exiting the second conduit of the heat exchanger system). 3 (configure).

[0067] The secondary fluid may include any of a variety of suitable process fluids described herein. In some embodiments, the secondary fluid may include a power cycle fluid and / or a molten salt. Non-limiting examples of secondary fluids are described elsewhere herein.

[0068] In some embodiments, the method includes passing a primary fluid containing tritium through a first conduit of a heat exchanger system. As described in more detail below, the primary fluid containing tritium can be a high-temperature reactor fluid passed through the first conduit from (a part of) a fusion reactor (e.g., from a tritium breeder blanket).

[0069] For example, referring back to FIGS. 1A-6D, in a heat exchanger system (e.g., systems 10, 30, 50, 60, 70, 80), a primary fluid (e.g., fluid 13) containing tritium may be passed through a first conduit (e.g., first conduit 12, 32, 52, 62, 72, 82).

[0070] In some embodiments, the method includes passing a secondary fluid through a second conduit of a heat exchanger system. For example, referring back to Figures 1A-6D, in a heat exchanger system (e.g., systems 10, 30, 50, 60, 70, 80), a secondary fluid (e.g., fluid 15) may be passed through a second conduit (e.g., conduits 14, 34, 54, 64, 74, 84). The secondary fluid entering the second conduit may have a lower temperature than the temperature of the primary fluid entering the first conduit and may include any of the various process fluids described elsewhere herein.

[0071] The first conduit and / or the second conduit can have any suitable cross-sectional shape and configuration. For example, the first conduit can include a pipe, such as first conduits 12, 32, 62, and 82 shown in Figures 1A-1C, 2-4, and 6. In another example, the first conduit can include a channel formed in one or more metal sheets, such as first conduits 52 and 72 in Figures 5 and 7. The second conduit, in some cases, can have the same or a different cross-sectional shape and configuration as the first conduit.

[0072] The first conduit and / or the second conduit may be formed from any suitable metal and / or metal alloy. In some embodiments, the metal and / or metal alloy comprises a creep-resistant alloy capable of withstanding stress (e.g., pressure exerted by a fluid contained within the conduit). Non-limiting examples of metals and / or metal alloys include nickel, copper, iron, chromium, cobalt, molybdenum, or alloys thereof. Non-limiting examples of alloys include Hastelloy N, Inconel 600, Inconel 617, Inconel 625, AISI 316L stainless steel, Monel, etc.

[0073] The first conduit and / or the second conduit can have any suitable dimension. For example, in some embodiments, the first conduit and / or the second conduit can have a cross-sectional dimension of at least 0.1 mm, at least 1 mm, at least 5 mm, at least 10 mm, at least 20 mm, at least 40 mm, at least 60 mm, or at least 80 mm. In some embodiments, the first conduit and / or the second conduit can have a cross-sectional dimension of 100 mm or less, 80 mm or less, 60 mm or less, 40 mm or less, 20 mm or less, 10 mm or less, 5 mm or less, or 1 mm or less. Combinations of the above ranges are also possible (e.g., at least 0.1 mm or more and 100 mm or less). Other ranges are also possible. In some embodiments, the cross-sectional dimension of the first conduit and the cross-sectional dimension of the second conduit can be the same or different.

[0074] The heat exchangers described herein can include any suitable number of first and / or second conduits. For example, in some embodiments, the heat exchanger can include at least 1, at least 2, at least 5, at least 10, at least 50, at least 100, at least 500, at least 1,000, at least 5,000, at least 10,000, at least 50,000, at least 100,000, or at least 500,000 first and / or second conduits. In some embodiments, a heat exchanger can include up to 1,000,000, up to 500,000, up to 100,000, up to 50,000, up to 10,000, up to 5,000, up to 1,000, up to 500, up to 100, up to 50, up to 10, or up to 5, or up to 2 first and / or second conduits. Combinations of the above ranges are also possible (e.g., at least 1 and up to 1,000,000). Other ranges are also possible. In some embodiments, the number of first conduits and the number of second conduits present in a heat exchanger can be the same or different.

[0075] The heat exchangers described herein may have any of a variety of additional components. In some embodiments, one or more pumps may be used in the heat exchanger system to circulate the primary fluid and / or secondary fluid. The heat exchanger system may further include a control system for regulating various conditions (e.g., temperature, pressure, flow rate, etc.) of the various fluids (e.g., primary fluid, secondary fluid, sweep gas, etc.) in the system. In some cases, an automatic leak detection system may be implemented throughout the heat exchanger system to detect leaks of the various fluids (e.g., primary fluid, secondary fluid, sweep gas) and / or tritium.

[0076] In some embodiments, a heat exchanger system for fusion power plant applications is described herein. In one set of embodiments, the heat exchanger system includes a first conduit and a second conduit thermally coupled to the first conduit. The conduit may be any structure that includes a fluid passageway for a fluid to flow through, and may be open or closed. In some cases, the conduit may have a cross-sectional dimension that is smaller than its longitudinal (i.e., axial) dimension. Non-limiting examples of the heat exchanger systems described herein are shown in FIGS. 1A-1C. As shown, the heat exchanger system 10 may include a first conduit 12 and a second conduit 14 thermally coupled to the first conduit 12. The first conduit 12 and the second conduit 14 may each include respective conduit walls 12B and 14B. As described in more detail below, the first conduit and / or the second conduit may have any of a variety of configurations, including, but not limited to, pipes, channels, etc.

[0077] 1A-1C illustrate one embodiment in which the first conduit and the second conduit each include a circular cross-section, it should be noted that not all embodiments described herein are so limited, and in other embodiments, the first conduit and / or the second conduit may include a cross-section having any suitable shape, e.g., square, rectangular, triangular, polygonal, elliptical, etc.

[0078] In some embodiments, the first conduit and the second conduit are thermally coupled to one another via a connector, which can be a solid material. For example, in one embodiment, the heat exchanger system includes a connector that thermally couples an outer surface of the first conduit to an outer surface of the second conduit. In some embodiments, the outer surface of the conduit can be the outermost surface of the conduit, such as the surface exposed to the environment surrounding the conduit.

[0079] 1A-1C. As shown, for example, first conduit 12 can include a conduit wall 12B having an outer surface 12A. Similarly, second conduit 14 can include a conduit wall 14B having an outer surface 14A. Heat exchanger system 10 can include a connector 16 that thermally couples outer surface 12A of first conduit 12 to outer surface 14A of second conduit 14. As shown, outer surfaces 12A and 14A can be the outermost surfaces of first and second conduits 12 and 14.

[0080] 1A-1C show one embodiment in which the first conduit and the second conduit each include a single conduit wall, it should be noted that not all embodiments described herein are so limited, and in other embodiments, the first conduit and / or the second conduit may include more than one conduit wall, such as, for example, a double-walled pipe having an inner wall and an outer wall concentric with the inner wall. In some embodiments, the connector may be configured to thermally couple the outer surface of the first conduit (e.g., the outermost surface of the outer wall) to the outer surface of the second conduit (e.g., the outermost surface of the outer wall).

[0081] In some embodiments, the connector that thermally couples the first and second conduits is a solid connector. Thus, the connector may be formed from a solid piece of material. In some cases, the solid material may not have any internal cavities (i.e., not exposed to the environment surrounding the material) and / or fluid passages (e.g., channels, conduits) disposed therein. For example, as shown in FIG. 1B, connector 16 is a solid connector without any internal cavities or fluid passages within the material. In some cases, the solid connector does not include pipes, channels, or the like.

[0082] In some embodiments, the heat exchanger system includes a gas flow device. The gas flow device may, in some cases, be positioned to flow gas (i.e., sweep gas) around the first conduit, the second conduit, and the connector (e.g., solid connector). Non-limiting examples of gas flow devices may include a pump, a fan, etc. For example, referring back to FIGS. 1A-1B , the heat exchanger system 10 may include a gas flow device 18 positioned to flow gas 20 around the first conduit 12, the second conduit 14, and the connector 16. The gas flow device may be positioned in any suitable location within the heat exchanger system, for example, so long as the gas can flow across a substantial portion (e.g., at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or all) of the exterior surfaces of the first conduit, the second conduit, and the connector. In some cases, the gas flow device may be arranged to generate a sweep gas (e.g., sweep gas 20 in FIG. 1A) having a flow direction substantially parallel to the longitudinal dimension of the first and / or second conduits, as shown, for example, in FIG. 1A. Additionally, in some cases, there may be more than one gas flow device.

[0083] In some embodiments, the heat exchanger system may be configured and operated to allow efficient heat transfer from a tritium-containing primary fluid to a secondary fluid. In some embodiments, the first conduit may be configured to contain a primary fluid containing tritium. Tritium may arise, for example, from the reaction of lithium in the fluid with neutrons from a nuclear fusion reaction, as shown in equations (1) and (2) above. The second conduit may be configured to contain a secondary fluid in some embodiments. Referring again to FIGS. 1A-1B, as a non-limiting example, the first conduit 12 may contain a primary fluid 13 containing tritium, and the second conduit 14 may contain a secondary fluid 15.

[0084] In some embodiments, the primary fluid is a tritium-containing fluid having a high inlet temperature (e.g., a "hot" stream). For example, the primary fluid can be a tritium-containing high-temperature fluid from a fusion reactor, such as a molten salt and / or liquid metal containing tritium. In some embodiments, the secondary fluid (e.g., a "cold" stream) has a lower inlet temperature compared to the primary fluid. Thus, heat is transferred from the primary or "hot" stream to the secondary or "cold" stream via a heat exchanger. The secondary fluid can be any of a variety of suitable process fluids described herein. In certain embodiments, the secondary fluid can contain a lower concentration of tritium than the primary fluid. In some examples, the secondary fluid can contain negligible amounts of tritium, if any. Non-limiting examples of process fluids include power cycle fluids and / or molten salts. Non-limiting examples of power cycle fluids include water, carbon dioxide, helium, air, etc. Non-limiting examples of molten salts that can be used as process fluids include various nitrates such as, for example, NaNO3, KNO3, NaNO2, etc.

[0085] In some embodiments, a connector thermally coupling a first conduit and a second conduit may be configured to transfer heat from a primary fluid contained in the first conduit to a secondary fluid contained in the second conduit. For example, as shown in Figures 1B-1C, a connector 16 may be configured to transfer heat 17 from a primary fluid 13 (e.g., a hot stream) in the first conduit 12 to a secondary fluid 15 (e.g., a cold stream) in the second conduit 14. Heat from the primary fluid 13 is transferred through the conduit wall 12B of the first conduit 12, through the connector 16, and then through the conduit wall 14B of the second conduit 14 to the secondary fluid 15.

[0086] The presence of a connector (e.g., a solid connector) can, in some cases, allow efficient heat transfer from the primary fluid to the secondary fluid while minimizing tritium permeation from the primary fluid to the secondary fluid. With reference to Figure 1C, for example, the connector can be configured to minimize tritium permeation from the primary fluid 13 to the secondary fluid 15, as discussed herein.

[0087] In certain embodiments, the heat exchanger system may include a sweep gas surrounding the first conduit, the second conduit, and the connector (e.g., the solid connector). For example, as shown in FIGS. 1A-1C, the heat exchanger system 10 may include a sweep gas 20 surrounding the first conduit 12, the second conduit 14, and the solid connector 16. According to some embodiments, the sweep gas may advantageously facilitate the removal of tritium from the primary fluid exiting the exterior surfaces of the first conduit and / or the connector into the sweep gas (e.g., via arrows 19 in FIG. 1C), e.g., such that the amount of tritium available for permeation through the connector into the secondary fluid is reduced. That is, the sweep gas acts as a tritium sink, and negligible amounts, if any, of tritium may be able to permeate into the secondary fluid, e.g., via diffusion through the connector and / or re-entry from the surrounding environment. In some embodiments, the sweep gas is configured to contain a portion of the tritium originating from the primary fluid. For example, as shown in FIG. 1C, sweep gas 20 may contain tritium originating from primary fluid 13 and may prevent or inhibit tritium from reaching primary fluid 13.

[0088] In particular, as described in more detail herein, the sweep gas may remove tritium from the primary fluid via any of a variety of suitable routes, such as, for example, via physical transfer (e.g., convective mass transfer) and / or chemical reaction (e.g., reacting the tritium with a reactive material to form a tritium-containing reaction product).

[0089] In some embodiments, the heat exchanger system includes a reactive material (e.g., a reactive gas, liquid, and / or solid) disposed externally of the first conduit and the second conduit. For example, the reactive material may be contained within a sweep gas. In some cases, the reactive material may be capable of reacting with or chemically bonding with tritium. In some cases, the tritium-containing reaction product may have a lower diffusivity than tritium. For example, referring again to FIGS. 1A-1C, the heat exchanger system 10 may include a reactive material (not shown) disposed externally of the first conduit 12, the second conduit 14, and / or the connector 16.

[0090] In some embodiments, the reactive material comprises a reactive gas capable of reacting with or chemically bonding with tritium. In some cases, the reactive gas may be (part of) the sweep gas, or the reactive gas itself may be the sweep gas. For example, referring again to FIGS. 1A-1C, the reactive material (not shown) may be a reactive gas that is (part of) the sweep gas 20. Alternatively or additionally, in some embodiments, the reactive material may be a reactive solid or liquid, for example, contained by, contained within, and / or adjacent to the sweep gas. Alternatively or additionally, in some embodiments, the reactive material may be disposed in the form of a reactive material coating disposed on the exterior surface of the first conduit, the second conduit, and / or the connector. For example, referring again to FIGS. 1A-1C, the reactive material (not shown) may be in the form of a reactive solid or liquid disposed within, contained within, and / or adjacent to the sweep gas 20. As another example, the reactive material may be disposed in the form of a reactive material coating disposed on the outer surface around the first conduit 12 , the second conduit 14 and / or the connector 16 .

[0091] 1A-1C illustrate one embodiment in which a heat exchanger system includes a first conduit and a second conduit thermally coupled by a connector, it should be noted that not all embodiments described herein are so limited, and in other embodiments, a heat exchanger system may include multiple first and / or second conduits coupled by at least one connector. For example, various embodiments of such heat exchanger systems are shown in FIGS. 2-6D, which are described in detail below.

[0092] In one set of embodiments, a heat exchanger system includes a plurality of first conduits and a plurality of second conduits thermally coupled to the plurality of first conduits. FIG. 2 provides a non-limiting example of such a heat exchanger system. As shown in FIG. 2, heat exchanger system 30 includes a plurality of first conduits 32 and a plurality of second conduits 34 thermally coupled to the plurality of first conduits 32. In some embodiments, at least one of the plurality of first conduits is thermally coupled to two or more (e.g., at least three, at least four, at least five, etc.) of the plurality of second conduits. Alternatively or additionally, at least one of the plurality of second conduits is thermally coupled to two or more (e.g., at least three, at least four, at least five, etc.) of the plurality of first conduits. For example, as shown in FIG. 2, at least one of the plurality of first conduits 32 is thermally coupled to two or more of the plurality of second conduits 34. Similarly, at least one of the plurality of second conduits 34 is thermally coupled to two or more of the plurality of first conduits 32 .

[0093] In some embodiments, the plurality of first conduits and the plurality of second conduits are arranged in an alternating configuration with respect to one another. Referring again to Figure 2 as a non-limiting example, the plurality of first conduits 32 and the plurality of second conduits 34 are arranged in an alternating configuration with respect to one another, such as, for example, arranged in a grid array, in this example. In some cases, the first conduits and second conduits may be arranged in an alternating configuration.

[0094] In some embodiments, the plurality of first conduits may be thermally coupled to the plurality of second conduits via one or more connectors. In some cases, the connectors may be solid connectors. In some cases, the connectors may couple an outer surface of at least one of the plurality of first conduits to at least two or more outer surfaces of the plurality of second conduits. For example, as shown in FIG. 2, the outer surface 32A of at least one of the plurality of first conduits 32 may be thermally coupled to two or more outer surfaces 34A of the plurality of second conduits 34 via connectors 36 (e.g., solid connectors). Alternatively or additionally, the outer surface of at least one of the plurality of second conduits may be thermally coupled to two or more outer surfaces of the plurality of first conduits. For example, as shown in FIG. 2, the outer surface 34A of at least one of the plurality of second conduits 34 may be thermally coupled to two or more outer surfaces 32A of the plurality of first conduits 32 via connectors 36 (e.g., solid connectors).

[0095] The plurality of first and second conduits may have any of a variety of characteristics described elsewhere herein. For example, at least some of the plurality of first conduits may be configured to contain a primary fluid (e.g., a hot stream) that includes tritium, as shown, for example, by primary fluid 13 in Figure 2. Additionally, in some embodiments, at least some of the plurality of second conduits may be configured to contain a secondary fluid (e.g., a cold stream) that includes a small amount (if any) of tritium, as shown, for example, by secondary fluid 15 in Figure 2.

[0096] In some embodiments, a connector thermally coupling the first and second conduits may be configured to transfer heat from a primary fluid contained in the first conduit to a secondary fluid contained in the second conduit. For example, as shown in Figure 2, a connector 36 may be configured to transfer heat 17 from a primary fluid 13 (e.g., a hot stream) in the first conduit 12 to a secondary fluid 15 (e.g., a cold stream) in the second conduit 15.

[0097] In some embodiments, the heat exchanger system includes a sweep gas surrounding the plurality of first conduits, the plurality of second conduits, and / or at least one connector. For example, as shown in FIG. 2, the heat exchanger system can include a sweep gas 20 surrounding the plurality of first conduits 32, the plurality of second conduits 34, and / or at least one connector 36. The sweep gas can have any of the characteristics described above. For example, in FIG. 2, the sweep gas can facilitate the removal of tritium from the primary fluid 13 and / or any tritium that has permeated into the connector 36 into the sweep gas 20 (e.g., via arrow 19). In this manner, the sweep gas 20 can include tritium originating from the primary fluid 13. Thus, the presence of the sweep gas can reduce the amount of tritium that can permeate through the connector into the secondary fluid.

[0098] The heat exchanger system depicted in FIG. 2 may have any of the various additional components and features previously described, including gas flow devices, reactive materials, etc. It should also be noted that the heat exchange system depicted in FIG. 2 may include any suitable number of first and second conduits. For ease of explanation, FIG. 2 depicts a single grid array of first and second conduits. However, it should be noted that the heat exchanger system may also include any suitable number of the grid arrays depicted in FIG. 2, with some of the grid arrays thermally coupled to one another via connectors as described herein.

[0099] It should be noted that while FIG. 2 illustrates one embodiment of a heat exchanger system including a plurality of first conduits and a plurality of second conduits arranged and constructed in a particular configuration, not all embodiments described herein are so limited, and in other embodiments, a heat exchanger system may include a plurality of first and second conduits arranged and constructed in any of a variety of suitable configurations described herein.

[0100] For example, Figure 3 illustrates a second embodiment of a heat exchanger system including a plurality of first conduits and a plurality of second conduits thermally coupled to the plurality of first conduits. As shown, heat exchanger system 50 includes a plurality of first conduits 52 and a plurality of second conduits 54 thermally coupled to the plurality of first conduits 52. In some embodiments, the plurality of first conduits includes conduits formed within one or more sheets of metal or metal alloy. For example, as shown in Figure 3, the plurality of first conduits 52 includes conduits formed within one or more sheets of metal and / or metal alloy, e.g., two sheets 53A and 53B.

[0101] In some embodiments, at least one of the plurality of first conduits is thermally coupled to two or more (e.g., at least three, at least four, at least five, etc.) of the plurality of second conduits. For example, as shown in FIG. 3, at least one of the plurality of first conduits 52 is thermally coupled to two or more (e.g., at least three, at least four, at least five, etc.) of the plurality of second conduits. Alternatively or additionally, at least one of the plurality of second conduits is thermally coupled to two or more (e.g., at least three, at least four, at least five, etc.) of the plurality of first conduits. For example, as shown in FIG. 3, at least one of the plurality of second conduits 54 is thermally coupled to two or more of the plurality of first conduits 52.

[0102] Similar to the heat exchanger system described in FIG. 2, the heat exchanger system 50 of FIG. 3 can include a plurality of first conduits thermally coupled to a plurality of second conduits via at least one connector (e.g., a solid connector). For example, as shown in FIG. 3, the heat exchanger system 50 includes a connector 56. An outer surface 52A of at least one of the plurality of first conduits 52 can be thermally coupled to two or more outer surfaces 54A of the plurality of second conduits 54 by the connector 56 (e.g., a solid connector). Similarly, an outer surface 54A of at least one of the plurality of second conduits 54 can be thermally coupled to two or more outer surfaces 52A of the plurality of first conduits 52 by the connector 56 (e.g., a solid connector). In some embodiments, the at least one connector can be in the form of one or more corrugated sheets, as shown in FIG. 3, for example.

[0103] In some embodiments, the plurality of first conduits, at least one solid connector, and the plurality of second conduits are arranged in alternating layers. Referring again to FIG. 3 as a non-limiting example, the plurality of first conduits 52, at least one solid connector 56, and the plurality of second conduits 54 may be arranged in alternating layers relative to one another. For example, the heat exchanger system 50 may include multiple layers alternating between layers of first conduits 52 and layers of second conduits 54, with a layer of at least one connector 50 disposed between each layer of first conduits 52 and each layer of second conduits 54. It should also be noted that the heat exchanger system depicted in FIG. 3 may include any suitable number of alternating layers of first conduits, solid connectors, and second conduits.

[0104] The plurality of first conduits and the plurality of second conduits may have any of the various characteristics described with respect to FIGS. 1A-2. For example, at least some of the plurality of first conduits may be configured to contain a primary fluid (e.g., a hot stream) containing tritium, as shown, for example, by primary fluid 13 in FIG. 3. Additionally, in some embodiments, at least some of the plurality of second conduits may be configured to contain a secondary fluid (e.g., a cold stream) containing negligible, if any, amounts of tritium, as shown, for example, by secondary fluid 15 in FIG. 3. In some embodiments, a connector 56 thermally coupling the plurality of first conduits 52 and the plurality of second conduits 54 may be configured to transfer heat from the primary fluid 13 contained within the first conduits 52 to the secondary fluid 15 contained within the second conduits 54. For example, as shown in FIG. 3, the connector 56 may be configured to transfer heat 17 from the primary fluid 13 (e.g., a hot stream) in the first conduit 12 to the secondary fluid 15 (e.g., a cold stream) in the second conduit 15.

[0105] According to some embodiments, as shown in FIG. 3 , the heat exchanger system 50 further includes a sweep gas 20 surrounding the plurality of first conduits 52 and the plurality of second conduits 54. The sweep gas may have any of the characteristics described above with respect to FIGS. 1A-2 . For example, the sweep gas may facilitate the removal of tritium from the primary fluid 13 (e.g., via arrow 19 in FIG. 3 ) and / or tritium that has permeated the connector 56 into the sweep gas 20. In this manner, the sweep gas 20 may include tritium originating from the primary fluid 13. In the presence of the sweep gas, the amount of tritium that permeates from the primary fluid through the connector to the secondary fluid may be reduced.

[0106] The heat exchanger system described in FIG. 3 may have any of the various additional components and features described above, including gas flow devices, reactive materials, and the like.

[0107] 4 illustrates another embodiment of a heat exchanger system 60 including a plurality of first conduits and a plurality of second conduits thermally coupled to the plurality of first conduits. As shown, the heat exchanger system 60 includes a plurality of first conduits 62 and a plurality of second conduits 64 thermally coupled to the plurality of first conduits 62. According to some embodiments, at least one of the plurality of first conduits 62 is thermally coupled to two or more of the plurality of second conduits 64. Similarly, at least one of the plurality of second conduits 64 may be thermally coupled to two or more of the plurality of first conduits 62.

[0108] Similar to the heat exchanger systems described in Figures 2-3, the heat exchanger system 60 of Figure 4 may include a plurality of first conduits thermally coupled to a plurality of second conduits via at least one connector (e.g., a solid connector). For example, as shown in Figure 4, the heat exchanger system 60 includes a connector 66 disposed between the plurality of first conduits 62 and the plurality of second conduits 64. An outer surface 62A of at least one of the plurality of first conduits 62 may be thermally coupled to two or more outer surfaces 64A of the plurality of second conduits 64 by the connector 66 (e.g., a solid connector). Similarly, an outer surface 64A of at least one of the plurality of second conduits 64 may be thermally coupled to two or more outer surfaces 62A of the plurality of first conduits 62 by the connector 66 (e.g., a solid connector).

[0109] In some embodiments, at least one connector may be in the form of a single corrugated sheet, as shown, for example, in Figure 4. In some embodiments, the first conduits and / or the second conduits may be coupled (e.g., soldered, welded, brazed, etc.) to a corrugated connector via an intermediate brazing material, e.g., metal. For example, as shown in Figure 4, the first conduits 62 and / or the second conduits 64 may be coupled (e.g., welded, brazed, etc.) to at least the connector via an intermediate brazing material 65.

[0110] According to some embodiments, the plurality of first conduits 62, at least one solid connector 66, and the plurality of second conduits 64 may be arranged in alternating layers relative to one another, as shown in Figure 4. For example, the heat exchanger system 60 may include multiple layers that are arranged alternating between layers of first conduits 62 and layers of second conduits 64, with a layer of at least one connector 60 arranged between each layer of first conduits 62 and each layer of second conduits 64. It should also be noted that the heat exchanger system depicted in Figure 4 may include any suitable number of alternating layers of first conduits, solid connectors, and second conduits.

[0111] According to some embodiments, as shown in FIG. 4, the heat exchanger system 60 further includes a sweep gas 20 surrounding the plurality of first conduits 62 and the plurality of second conduits 64. The sweep gas may have any of the characteristics described above with respect to FIGS. 1A-3, for example. For example, the sweep gas may facilitate the removal of tritium from the primary fluid 13 (e.g., via arrow 19 in FIG. 3) and / or tritium that has permeated into the connector 66 into the sweep gas 20. In this manner, the sweep gas 20 may include tritium originating from the primary fluid 13. Thus, the presence of the sweep gas may reduce the amount of tritium available to permeate from the primary fluid through the connector into the secondary fluid.

[0112] The heat exchanger system described in FIG. 4 may have any of the various additional components and features described above, including gas flow devices, reactive materials, etc.

[0113] 5 illustrates yet another embodiment of a heat exchanger system 70 including a plurality of first conduits and a plurality of second conduits thermally coupled to the plurality of first conduits. As shown, heat exchanger system 70 includes a plurality of first conduits 72 and a plurality of second conduits 74 thermally coupled to the plurality of first conduits 72. According to some embodiments, at least one of the plurality of first conduits 72 may be thermally coupled to two or more of the plurality of second conduits 74. Similarly, at least one of the plurality of second conduits 74 may be thermally coupled to two or more of the plurality of first conduits 72.

[0114] 1A-4, the heat exchanger system 70 of FIG. 5 may include a plurality of first conduits thermally coupled to a plurality of second conduits via at least one connector (e.g., a solid connector). For example, as shown in FIG. 5, the heat exchanger system 70 may include a connector 76 disposed between the plurality of first conduits 72 and the plurality of second conduits 74. An outer surface 72A of at least one of the plurality of first conduits 72 may be thermally coupled to two or more outer surfaces 74A of the plurality of second conduits 74 by the connector 76 (e.g., a solid connector). Similarly, an outer surface 74A of at least one of the plurality of second conduits 74 may be thermally coupled to two or more outer surfaces 72A of the plurality of first conduits 72 by the connector 76 (e.g., a solid connector).

[0115] In some embodiments, the first plurality of conduits and / or the second plurality of conduits may be formed from corrugated sheets of metal and / or metal alloy. For example, as shown in Figure 5, the first plurality of conduits 72 and the second plurality of conduits 74 may each be formed from two sheets of metal and / or metal alloy, e.g., 73A and 73B.

[0116] According to some embodiments, the plurality of first conduits 72, at least one solid connector 76, and the plurality of second conduits 74 may be arranged in alternating layers relative to one another, as shown in Figure 4. For example, the heat exchanger system 70 may include multiple layers that are alternated between layers of first conduits 72 and layers of second conduits 74, with a layer of at least one connector 70 disposed between each layer of first conduits 72 and each layer of second conduits 74. It should also be noted that the heat exchanger system depicted in Figure 5 may include any suitable number of alternating layers of first conduits, solid connectors, and second conduits.

[0117] The plurality of first conduits, second conduits, and connectors described with respect to Figures 4-5 may have any of the various characteristics described herein. For example, at least some of the plurality of first conduits may be configured to contain a primary fluid (e.g., a hot stream) containing tritium, e.g., primary fluid 13. Additionally, in some embodiments, at least some of the plurality of second conduits may be configured to contain a secondary fluid (e.g., a cold stream) containing small amounts, if any, of tritium, e.g., secondary fluid 15. The connectors may be configured to transfer heat 17 from the primary fluid 13 (e.g., a hot stream) in the plurality of first conduits to the secondary fluid 15 (e.g., a cold stream) in the plurality of second conduits.

[0118] The heat exchanger systems described in FIGS. 4-6 may have any of the various additional components and characteristics described above, including, for example, gas flow devices, sweep gases, reactive materials, etc. Also, for example, the heat exchanger systems described in FIGS. 4-6 may include a sweep gas 20 surrounding the plurality of first conduits and the plurality of second conduits. The sweep gas may have any of the characteristics described above with respect to FIGS. 1-3. For example, the sweep gas may facilitate the removal of tritium 19 from the primary fluid 13 and / or tritium that has permeated the connectors into the sweep gas 20. In this manner, the sweep gas 20 may contain tritium originating from the primary fluid 13. Thus, the presence of the sweep gas may advantageously reduce the amount of tritium that can permeate through the connectors into the secondary fluid.

[0119] 2-5 illustrate various embodiments of heat exchanger systems including a plurality of first conduits and a plurality of second conduits arranged in an interleaved configuration, it should be noted that not all embodiments described herein are so limited, and in other embodiments, the first and second conduits within the heat exchanger may be arranged in other configurations, for example, a coiled or wound configuration. Figures 6A-6D illustrate a non-limiting embodiment of a heat exchanger system having a coiled configuration.

[0120] FIG. 6A is a schematic diagram illustrating a cross section of a single heat exchanger unit 80A that can be used to form a heat exchanger system having a coiled configuration. As shown in FIG. 6A, the heat exchanger unit includes a first conduit 82 and a second conduit 84 thermally coupled to the first conduit 82. Similar to the heat exchanger systems described in FIGS. 1A-5, the heat exchanger unit can include a connector 86 (e.g., a solid connector) configured to thermally couple the first conduit 82 to the second conduit 84. In some cases, the connector 86 can thermally couple an outer surface 82A of the first conduit 82 to an outer surface 84A of the second conduit 84. In some examples, as shown in FIG. 6A, the first conduit 82 and / or the second conduit 84 can be coupled (e.g., welded, brazed, etc.) to the connector 86 via an intermediate brazing material 85.

[0121] In some embodiments, the first conduit and the second conduit may be disposed on the same side of a connector (e.g., a solid connector). For example, as shown in FIG. 6A, in heat exchanger unit 80A, first conduit 82 and second conduit 84 may be disposed on (e.g., attached to) a first side of connector 86.

[0122] First conduit 82 may be configured to contain a primary fluid 13 including tritium, and second conduit 84 may be configured to contain a secondary fluid 15. According to some embodiments, connector 86 may be configured to transfer heat 17 from primary fluid 13 contained within first conduit 82 to secondary fluid 15 contained within second conduit 84, for example, as indicated by flow arrow 17.

[0123] In some embodiments, the heat exchanger unit may further include an insulating layer adjacent the connector. For example, as shown in FIG. 6A, the heat exchanger unit may further include an insulating layer 88 disposed adjacent the connector 86 on the side opposite the first conduit 82 and the second conduit 84. The insulating layer may, in some cases, prevent the transfer of heat from the connector 86 to an area located below the insulating layer 88 on the side opposite the connector 86.

[0124] In some embodiments, a heat exchanger unit (e.g., heat exchanger unit 80A of FIG. 6A) may be wound or rolled to form a coiled heat exchanger unit. For example, as shown in FIGS. 6A-6B, heat exchanger unit 80A of FIG. 6A may be wound or rolled about a center axis to form heat exchanger unit 80B having a coiled configuration (e.g., a cylindrical heat exchanger unit). FIG. 6B shows a cross section of a portion of heat exchanger unit 80B having a coiled configuration. As shown, the cross section of coiled heat exchanger unit 80B includes repeating units of heat exchanger unit 80A. A side view of coiled heat exchanger unit 80B is also shown in FIG. 6C. For example, as shown in FIG. 6C, a coil heat exchanger unit 80B may include a first conduit inlet 82C for supplying a primary fluid, a first conduit outlet 82D for outputting the primary fluid, a second conduit inlet 84C for supplying a secondary fluid, and a second conduit outlet 84D for outputting the secondary fluid.

[0125] In some embodiments, a heat exchanger system can include multiple coiled heat exchanger units. A top-down view of a non-limiting example of such a heat exchanger system is shown in FIG. 6D. For example, as shown in FIG. 6D, heat exchanger system 80C can include multiple coiled heat exchanger units 80B shown in FIG. 6C. In certain embodiments, multiple heat exchanger units can be connected to a manifold to form a heat exchanger system. For example, as described in more detail below, the manifold can be configured to route first and / or second conduits from various coiled heat exchanger units to a single inlet pipe and a single outlet pipe for each fluid type (e.g., primary fluid, secondary fluid) described herein.

[0126] 6D shows a non-limiting example of a manifold that may be used in heat exchanger system 80C. For example, in FIG. 6D, heat exchanger system 80C may include manifold 89. Manifold 89 may include a plurality of pipes, including, for example, primary fluid inlet pipe 113A, primary fluid outlet pipe 113B, secondary fluid inlet pipe 115A, and secondary fluid outlet pipe 115B. The inlet and outlet pipes may fluidly connect various inlets and outlets of the first and second conduits from each of the plurality of coiled heat exchanger units 80B. For example, as shown in Figures 6C-6D, primary fluid inlet pipe 113A may be fluidly connected to first conduit inlet 82C on heat exchanger unit 80B, secondary fluid inlet pipe 115A may be fluidly connected to secondary conduit inlet 84C on heat exchanger unit 80B, primary fluid outlet pipe 113B may be fluidly connected to first conduit outlet 82D on heat exchanger unit 80B, and secondary fluid outlet pipe 115B may be fluidly connected to secondary conduit outlet 84D.

[0127] In some embodiments, a manifold may be configured to route a primary fluid stream to a plurality of first conduits within a heat exchanger unit and / or a secondary fluid stream to a plurality of second conduits within a heat exchanger unit via its fluid inlet pipes. For example, as shown in Figures 6C-6D, a manifold 89 may be configured to route primary fluid inlet flow path 13A through primary fluid inlet pipe 113A to first conduit inlet 82C on heat exchanger unit 80B and / or secondary fluid inlet flow path 15A through secondary fluid inlet pipe 115A to second conduit inlet 84C on heat exchanger unit 80B.

[0128] In some embodiments, a manifold may be configured to receive a primary fluid stream from a plurality of first conduits within a heat exchanger unit and / or a secondary fluid from a plurality of second conduits within the heat exchanger unit via its fluid outlet pipes. For example, via the manifold 90 shown in Figures 6C-6D, a primary fluid outlet pipe 113B may be configured to receive a primary fluid outlet stream 13B from a first conduit outlet 82C of the heat exchanger unit 80B and / or a secondary fluid outlet pipe 115B may be configured to receive a secondary fluid outlet stream 15B from a second conduit outlet 84C of the heat exchanger unit 80B.

[0129] It should be noted that while Figure 6D illustrates a manifold for use with a particular type of heat exchanger system (e.g., a heat exchanger system having a wound or coiled configuration), not all embodiments described herein are so limited, and in other embodiments, the manifold may be used with any of the various heat exchanger systems described herein and / or with respect to Figures 2-5. For example, although not shown in Figures 2-5, the various heat exchanger systems 30, 50, 60, and 70 may each include a manifold similar to that shown in Figure 6D. For example, in Figures 2-5, the manifold (not shown) may include a primary fluid inlet pipe (e.g., an inlet pipe such as inlet pipe 113A in Figure 6D) configured to channel primary fluid 13 into a plurality of first conduits (e.g., first conduits 32, 52, 62, 72) and / or a secondary fluid inlet pipe (e.g., an inlet pipe such as inlet pipe 115A in Figure 6D) configured to channel secondary fluid 15 into a plurality of second conduits (e.g., second conduits 34, 54, 64, 74). Additionally or alternatively, the manifold (not shown) may further include a primary fluid outlet pipe (e.g., an outlet pipe such as outlet pipe 113B in FIG. 6D ) configured to receive the primary fluid 13 exiting from a plurality of first conduits (e.g., first conduits 32, 52, 62, 72) and / or a secondary fluid outlet pipe (e.g., an outlet pipe such as outlet pipe 115B in FIG. 6D ) configured to receive the secondary fluid 15 exiting from a plurality of second conduits (e.g., second conduits 34, 54, 64, 74).

[0130] The heat exchanger units and / or systems 80A-80C depicted in Figures 6A-6D may have any of the various additional components and characteristics previously described, such as, for example, gas flow devices, sweep gases, primary fluids, secondary fluids, and reactive materials. For example, the heat exchanger systems and / or units may further include a sweep gas (e.g., gas 20) surrounding the first conduit 82 and the second conduit 86. The sweep gas may have any of the characteristics previously described. For example, the sweep gas may facilitate the removal of tritium from the primary fluid 13 (e.g., via arrow 19 in Figure 6A) and / or tritium that has permeated the connector 86 into the sweep gas 20. In this manner, the sweep gas 20 may include tritium originating from the primary fluid 13.

[0131] As mentioned above, the heat exchanger systems described herein can be used to harness the energy produced from a fusion reaction and to extract and recycle the removed tritium. In some embodiments, the heat exchanger system can be part of a fusion plant or other plant as described herein. The fusion reaction represented by equations (1)-(2) (e.g., the deuterium-tritium fusion reaction) can be carried out in a fusion plant.

[0132] A non-limiting example of a fusion power plant including a heat exchanger system is shown in Figure 9. For example, as shown in Figure 9, in a fusion power plant 130, a fusion reaction (e.g., as illustrated by Equation (1)) may occur in a reactor 131 (e.g., in the plasma of the reactor). In some embodiments, energy and neutrons 131A released from the fusion reaction may be passed through a tritium breeder blanket 132, where the energy from the reaction may be stored as thermal energy and additional tritium may be produced via a second reaction (e.g., as illustrated by Equation (2)). As a result, in some cases, the tritium breeder blanket 132 may contain a high-temperature fluid 133A containing a relatively large amount of tritium.

[0133] 9, the tritium-containing high-temperature fluid 133A (e.g., primary fluid) may then be fed to a heat exchanger system 120. Using the heat exchanger system, the thermal energy stored within the tritium-containing high-temperature fluid 133A may be transferred to a process fluid, such as a fluid that may be transported from a fusion power plant and then used to generate power. Additionally, tritium within the tritium-containing high-temperature fluid 133A may be effectively extracted by a sweep gas within the heat exchanger and then recycled. The heat exchanger system 120 may be any of the various heat exchanger systems described herein. For example, the heat exchanger 120 may have any of the various components described herein (e.g., first and second conduits, connectors, sweep gas, reactive materials) and may be operated as described herein.

[0134] In some embodiments, the fusion power plant may optionally include a tritium extractor upstream of the heat exchanger system. The tritium extractor may be configured for use in performing primary tritium extraction on the tritium-containing primary fluid prior to feeding the fluid into the heat exchanger. For example, as shown in FIG. 9, the fusion power plant may include a tritium extractor 134 located upstream of the heat exchanger 120. As the hot fluid 133A flows through the tritium extractor 134, a substantially pure tritium-extracted stream 134B and a hot fluid 133B containing a relatively low amount of tritium may be produced. In some examples, the tritium-containing hot fluid 133B may then be pumped into the heat exchanger 120 as stream 113C via pump 135A.

[0135] In some embodiments, a heat exchanger system may be used to transfer heat from a tritium-containing primary fluid to a secondary fluid. For example, as shown in FIG. 9, a hot tritium-containing fluid 133C (e.g., a primary fluid inlet stream) and a cold process fluid 135C (e.g., a secondary fluid inlet stream) may be passed through a heat exchanger 120 for heat exchange. As shown by step 104 in FIG. 8, within the heat exchanger 120, heat may be directed from the hot tritium-containing fluid 133C (e.g., a primary fluid) through a connector (not shown) to the cold process fluid 135C (e.g., a secondary fluid) contained within a second conduit of the heat exchanger. After passing through the heat exchanger 120, a hot process fluid 135D (e.g., a secondary fluid output stream) and a cold fluid 133D (e.g., a primary fluid output stream) may be produced. In some cases, the cold fluid 133D may be passed through a pump 135B and recycled to various portions of the fusion power plant 130, such as the tritium breeder blanket 132.

[0136] In some embodiments, a heat exchanger system may be used to remove tritium from a tritium-containing primary fluid into a sweep gas. For example, as shown in Figure 9, a sweep gas (not shown) may flow around a first conduit, a second conduit, and a connector (not shown) to remove tritium from a high-temperature tritium-containing fluid 133C (e.g., a primary fluid). In some cases, the removed tritium may react with reactive materials (e.g., solid, liquid, and / or gaseous reactive materials) in the heat exchanger and / or sweep gas to form one or more tritium-containing reaction products.

[0137] In some embodiments, a heat exchanger may be used to extract tritium from the sweep gas and / or one or more tritium-containing reaction products (if formed). For example, as shown in FIG. 9, heat exchanger system 120 may produce stream 133D (e.g., a stream containing the sweep gas and / or one or more tritium-containing reaction products with removed tritium). Stream 133D may, in some cases, be passed to a tritium separator (not shown) for secondary tritium extraction. According to some embodiments, the extracted tritium may be recycled back into the plasma of fusion reactor 131 to participate in additional fusion reactions (e.g., deuterium-tritium fusion reactions).

[0138] Certain aspects of the present disclosure relate to methods of manufacturing heat exchanger systems, such as, for example, the heat exchanger systems described herein.

[0139] In some embodiments, a method of manufacturing a heat exchanger system includes forming a plurality of first conduits, as shown in step 92 of Figure 7. The plurality of first conduits may be formed from a material (e.g., a metal or metal alloy) having any of a variety of suitable shapes. For example, in one set of embodiments, the plurality of first conduits may be formed from pipes or tubes (e.g., metal pipes or tubes), as shown in Figures 2, 4, and 6A-6D.

[0140] In another set of embodiments, forming the plurality of first conduits includes forming the conduits from one or more sheets of metal or metal alloy, e.g., as shown in Figures 3 and 5. For example, as shown in Figure 5, forming the plurality of first conduits includes forming two corrugated metal sheets (e.g., metal sheets 73A and 73B) and then joining (e.g., bonding) the two corrugated metal sheets together in predetermined areas. In some embodiments, forming the one or more corrugated metal sheets includes rolling and / or extruding one or more corrugated metal sheets. The resulting plurality of first conduits can have any suitable shape, e.g., rectangular, polygonal, etc.

[0141] In yet another set of embodiments, forming the plurality of first conduits includes forming a plurality of channels on a surface of a first metal sheet and then joining a surface of a second metal sheet to the surface of the first metal sheet to form the sealed channels. A non-limiting example of an embodiment is shown in FIG. 3. As shown, the plurality of channels may first be formed on the surface of the first metal sheet 53B. The plurality of channels may be formed via cutting and / or etching the surface of the first metal sheet. The first metal sheet 53B containing the plurality of channels may then be joined to the surface of the second metal sheet 53B to form the sealed channels (i.e., the first conduits 52). Joining the first metal sheet to the surface of the second metal sheet may use any of a variety of methods, including, but not limited to, brazing and / or diffusion welding.

[0142] In some embodiments, a method of manufacturing a heat exchanger system includes forming at least one connector (e.g., a solid connector), for example, as shown in step 94 of FIG. 7. The at least one connector may be formed from a material (e.g., a metal or metal alloy) having any of a variety of suitable shapes. For example, in one set of embodiments, the at least one connector may be formed from one or more flat sheets of metal and / or metal alloy, for example, as shown in FIGS. 2-6. In some embodiments, the connector may be formed from a single corrugated sheet of metal or metal alloy, for example, as shown in FIGS. 3-4.

[0143] In some embodiments, forming the at least one connector includes forming one or more corrugated sheets of metal and / or metal alloy, for example, as shown in Figures 3-4. For example, the one or more corrugated metal sheets may be formed by rolling and / or extruding one or more metal sheets and / or metal alloys.

[0144] In some embodiments, a method of manufacturing a heat exchanger system includes forming a plurality of second conduits, as shown in step 96 of Figure 7. The plurality of second conduits may be formed from a material (e.g., a metal or metal alloy) having any of a variety of suitable shapes. For example, in one set of embodiments, the plurality of second conduits may be formed from pipes or tubes (e.g., metal pipes or tubes), as shown in Figures 2-4 and 6A-6C.

[0145] In another set of embodiments, forming the plurality of second conduits includes forming the conduits from one or more sheets of metal or metal alloy, for example, as shown in Figure 5. For example, in Figure 5, forming the plurality of first conduits includes forming two corrugated metal sheets (e.g., metal sheets 75A and 75B) and then joining (e.g., bonding) the two corrugated metal sheets together in predetermined areas. The resulting plurality of first conduits can have any suitable shape, e.g., rectangular, polygonal, square, etc.

[0146] In some embodiments, the manufacturing method includes stacking a plurality of first conduits, at least one solid connector, and a plurality of second conduits in alternating layers, e.g., as shown in Figure 7 and step 98 of Figures 2-6. For example, according to some embodiments, the various components may be stacked in such a way that at least one solid connector thermally couples the plurality of first conduits to the plurality of second conduits, e.g., as shown in Figures 2-6B.

[0147] For example, and referring back to Figure 3 as a non-limiting example, in forming a layer including a plurality of first conduits 52, a plurality of second conduits 54, and at least one corrugated connector sheet 56, the corrugated connector sheets 56 may be overlaid on both sides of the layer including the plurality of first conduits 52. The plurality of second conduits 54 may be overlaid on the corrugated connector sheet 56 on the side opposite the layer including the plurality of first conduits 52. In this manner, the at least one corrugated connector 56 may thermally couple the plurality of first conduits 52 to the plurality of second conduits 54 in an alternating configuration.

[0148] In some embodiments, the manufacturing method includes joining stacked alternating layers of first conduits, connectors, and second conduits, as shown, for example, in step 100 of Figure 7. The stacked alternating layers may be joined by any suitable method described herein. In one set of embodiments, as shown in Figures 2-6B, the stacked alternating layers may be joined via brazing, welding, etc. In some cases, a brazing material, as shown in Figure 4, may be introduced between the stacked layers to bond the stacked layers together.

[0149] Certain aspects of the present disclosure are directed to methods of using the heat exchanger systems described herein. FIG. 8 shows a flowchart illustrating one non-limiting embodiment of such a method. The heat exchanger system can be any of the heat exchanger systems described herein. The heat exchanger system can include any of the various components described herein, including at least one (e.g., multiple) first conduits, at least (e.g., multiple) second conduits, and at least one (e.g., multiple) connectors (e.g., solid connectors), a sweep gas, etc. As shown in step 102, a primary fluid containing tritium can be passed through the first conduit of the heat exchanger system. Additionally, as shown in step 103, a secondary fluid can be passed through the second conduit of the heat exchanger system. As shown in step 104, heat from the primary fluid can be directed through the connector (e.g., solid connector) to a secondary fluid contained in the second conduit of the heat exchanger. Next, as shown in step 106, a sweep gas (e.g., an inert sweep gas and / or a reactive sweep gas) may be flowed around the first conduit, the second conduit, and the connector to remove tritium from the primary fluid and the connector. As shown in step 107, when tritium from the primary fluid exits the exterior surface of the first conduit, it may react with a reactive material (e.g., a reactive solid, a reactive liquid, and / or a reactive gas) described herein disposed outside the first conduit to form one or more tritium-containing reaction products. As shown in step 108, tritium may be extracted from the sweep gas and / or the tritium-containing reaction products formed in the heat exchanger system. Optionally, the extracted tritium may be recycled to the fusion power plant, as shown in step 110.

[0150] U.S. Provisional Patent Application Serial No. 63 / 344,329, filed May 20, 2022, entitled "Tritium Shunt Heat Exchanger Using Sweep Gas," is hereby incorporated by reference in its entirety.

[0151] The following examples are intended to illustrate certain embodiments of the present disclosure, but do not exemplify the full scope of the disclosure.

[0152] Example 1 This example describes a heat exchanger system including alternating layers of first and second conduits, according to certain embodiments.

[0153] As shown in FIG. 10A, a heat exchanger unit cell can include a first conduit (e.g., a nickel tube) and a second conduit (e.g., a 6.4 mm outer diameter Inconel 625 tube). The first conduit can contain a high-temperature FLiBe molten salt containing tritium, and the second conduit can contain a low-temperature CO2 process fluid. The first conduit can be thermally coupled to the second conduit through a sheet of copper / tungsten / copper laminate. A sweep gas can flow across the first conduit, the second conduit, and the exterior of the laminate. Heat can be transferred from the FLiBe molten salt to the CO2 process fluid through the laminate. The sweep gas can remove a majority of the tritium exiting the exterior of the first conduit.

[0154] The heat exchanger unit cells of Figure 10A can be stacked into a heat exchanger system comprising alternating layers of tubes and copper sheets, for example, as shown in 10B. The tubes can be brazed bonded to the sheets via fillets.

[0155] While several embodiments of the present disclosure have been described and illustrated herein, those skilled in the art will readily envision various other means and / or structures for carrying out the functions and / or results and / or one or more advantages described herein, and each such variation and / or modification is deemed to be within the scope of the present disclosure. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and that the actual parameters, dimensions, materials, and / or configurations will depend on the particular application or applications for which the teachings of the present disclosure are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific embodiments of the present disclosure described herein. Accordingly, it should be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and their equivalents, the present disclosure may be practiced otherwise than as specifically described and claimed. The present disclosure is directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits and / or methods, provided that such features, systems, articles, materials, kits and / or methods are not mutually inconsistent, is included within the scope of the present disclosure.

[0156] In the event that the present specification and a document incorporated herein by reference include conflicting and / or inconsistent disclosure, the present specification shall control. If two or more documents incorporated herein by reference include conflicting and / or inconsistent disclosure with respect to each other, the document having the later effective date shall control.

[0157] All definitions defined and used herein should be understood to govern any dictionary definitions, definitions in documents incorporated herein by reference, and / or ordinary meaning of the defined terms.

[0158] The indefinite articles "a" and "an," as used in the specification and claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

[0159] The phrase "and / or" as used in the specification and claims should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are present conjunctively in some cases and disjunctively in other cases. Multiple elements listed with "and / or" should be construed in the same manner, i.e., "one or more" of the elements so conjoined. Optionally, other elements other than the elements specifically identified by the "and / or" clause can be present, whether related to the elements specifically identified or not. Thus, as a non-limiting example, a reference to "A and / or B," when used in combination with open-ended language such as "comprising," can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements), etc.

[0160] As used in this specification and in the claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" should be interpreted as inclusive, i.e., including more than one of a number or list of elements, but also, optionally, including additional items not in the list. Only terms clearly indicating the contrary, such as "only one of," "exactly one of," or, when used in the claims, "consisting of," will refer to the inclusion of exactly one element of a number or list of elements. In general, the term "or" as used herein should be interpreted as indicating exclusive alternatives (i.e., "one or the other, but not both") only when preceded by terms indicating exclusivity, such as "either," "one of," "either / or," "exactly one of," or "exactly one of."

[0161] As used herein and in the claims, the phrase "at least one" in reference to a list of one or more elements should be understood to mean at least one element selected from any one or more elements in the list of elements, but not necessarily including at least one of each and every element specifically listed in the list of elements, and not excluding any combination of elements in the list of elements. This definition also allows for the optional presence of elements other than those specifically identified in the list of elements to which the phrase "at least one" refers, whether related or unrelated to the specifically identified elements. Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B," or, equivalently, "at least one of A and / or B") can refer, in one embodiment, to at least one with no B present (and optionally including elements other than B), optionally including one or more As; in another embodiment, to at least one with no As present (optionally including elements other than As), optionally including more than one B; in yet another embodiment, to at least one with optionally more than one As and optionally more than one B (optionally including other elements); etc.

[0162] As used herein, when the word "about" is used in connection with a number, it should be understood that yet another embodiment of the present disclosure includes that number unmodified by the presence of the word "about."

[0163] Also, unless expressly stated to the contrary, in methods claimed herein that include multiple steps or acts, it should be understood that the order of the method steps or acts is not necessarily limited to the order in which the method steps or acts are described.

[0164] As in the specification above, in the claims, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," "comprising," and the like, are to be understood to be open-ended. Only the transitional phrases "consisting of" and "consisting essentially of" are closed or semi-closed transitional phrases, respectively, as defined in U.S. Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

1. First conduit; Second conduit; a solid connector thermally coupling an outer surface of the first conduit to an outer surface of the second conduit; and a gas flow device positioned to flow gas around the first conduit, the second conduit, and the solid connector; a heat exchanger system including:

2. The solid connector is 10 －６ mole m －１ s －１ MPa －１／２ 10. The heat exchanger system of claim 1, having a permeability to tritium of:

3. The solid connector has a resistance of at least 20 W m at a temperature of 850 K. －１ K －１ 3. The heat exchanger system according to claim 1, wherein the heat exchanger system has a thermal conductivity of 0.1 to 0.

5.

4. 4. The heat exchanger system of claim 1, wherein the solid connector includes a surface exposed to the gas and a cross-section perpendicular to a direction in which the solid connector extends from the first conduit to the second conduit, the solid connector having a surface area that is at least 0.5 times the cross-sectional area of the solid connector.

5. Solid connectors are at least 10 １０ N ３／２ mole －１ K －１ 5. The heat exchanger system of claim 1, wherein the heat exchanger system has a ratio of thermal conductivity to tritium permeability of 1000 ppm or less.

6. The heat exchanger of any one of claims 1 to 5, wherein the solid connector comprises a metal and / or a metal alloy.

7. A heat exchanger according to any one of claims 1 to 6, wherein the gas flow device comprises a pump and / or a fan.

8. 8. The heat exchanger of claim 1, wherein the first conduit, the second conduit and / or the solid connector comprises a coating configured to reduce permeability to tritium.

9. a first conduit containing a primary fluid, the primary fluid containing tritium; a second conduit containing a secondary fluid, the secondary fluid containing a lower concentration of tritium than the primary fluid; a solid connector thermally coupling an outer surface of the first conduit to an outer surface of the second conduit; and a sweep gas surrounding the first conduit, the second conduit, and the solid connector, the sweep gas containing tritium originating from the primary fluid; a heat exchanger system including:

10. 10. The heat exchanger system of claim 9, wherein the solid connector is constructed and arranged so that at least 50% of the tritium leaving the primary fluid diffuses into the sweep gas before reaching the secondary fluid.

11. 11. The heat exchanger system of claim 9, wherein the solid connector is constructed and arranged so that at least 90% of the tritium leaving the primary fluid diffuses into the sweep gas before reaching the secondary fluid.

12. The heat exchanger system of any one of claims 9 to 11, wherein the primary fluid comprises a molten salt containing lithium.

13. The heat exchanger system of any one of claims 9 to 12, wherein the primary fluid comprises a liquid metal containing lithium.

14. The heat exchanger system of any one of claims 9 to 13, wherein the primary fluid comprises water.

15. The heat exchanger system according to any one of claims 12 to 14, wherein the molten salt and / or liquid metal contains beryllium and / or lead.

16. The molten salts are FLiBe, FLiNaK, FLiNaBe, and LiF—PbF ２ 16. The heat exchanger system of any one of claims 12 to 15, comprising a salt selected from the group consisting of a mixture of:

17. The primary fluid is at least 10 －６ moles / m ３ The heat exchanger system of any one of claims 9 to 16, containing tritium.

18. The heat exchanger system of any one of claims 9 to 16, wherein the secondary fluid comprises a power cycle fluid and / or a molten salt.

19. 20. The heat exchanger of claim 18, wherein the power cycle fluid comprises one or more of carbon dioxide, water, air, and / or helium.

20. 20. The heat exchanger system of claim 9, wherein the sweep gas has a tritium partial pressure of 100 Pa or less.

21. The heat exchanger system of any one of claims 9 to 20, wherein the sweep gas comprises an inert sweep gas.

22. A heat exchanger system according to any one of claims 9 to 21, wherein the sweep gas comprises a reactive material.

23. 23. The heat exchanger system of claim 22, wherein the reactive material comprises a reactive solid and / or a reactive sweep gas.

24. 24. The heat exchanger system of any one of claims 9 to 23, wherein the sweep gas comprises a gas selected from the group consisting of oxygen, carbon dioxide, nitrogen, chlorine, fluorine, helium, argon, neon, krypton and air.

25. The heat exchanger system of any one of claims 9 to 24, wherein the sweep gas comprises an inert gas selected from the group consisting of helium, argon, neon and krypton.

26. a first conduit containing a primary fluid, the primary fluid containing tritium; a second conduit thermally coupled to the first conduit, the second conduit containing a secondary fluid; and a reactive material disposed outside the first conduit and the second conduit, the reactive material reacting with tritium exiting the outer surface of the first conduit; a heat exchanger system including:

27. 27. The heat exchanger system of claim 26, wherein the reactive material comprises a reactive sweep gas.

28. 28. The heat exchanger system of claim 27, wherein the reactive sweep gas comprises a gas selected from the group consisting of oxygen, carbon dioxide, nitrogen, chlorine, and fluorine.

29. The heat exchanger system of any one of claims 26 to 28, wherein the reactive material comprises a reactive solid.

30. 30. The heat exchanger system of claim 29, wherein the reactive solid comprises a material selected from the group consisting of copper (II) oxide, iron oxide, nickel oxide, chromium oxide, titanium, cerium, lanthanum, barium, zirconium, activated carbon, and zeolites.

31. Iron oxide is hematite (Fe ２ O ３ ) and / or magnetite (Fe ３ O ４ 31. The heat exchanger system of claim 30, comprising:

32. 32. The heat exchanger system of any one of claims 26 to 31, wherein the reactive material is capable of reacting with tritium to produce tritiated water, tritiated ammonia, tritiated methane, tritium chloride and / or metal hydrides.

33. A heat exchanger system according to any one of claims 26 to 31, wherein the reactive material is capable of absorbing and / or binding tritium to active sites present on the surface of the reactive material.

34. The primary fluid is at least 10 －６ moles / m ３ 34. The heat exchanger system of any one of claims 26 to 33, comprising:

35. A heat exchanger system according to any one of claims 26 to 34, wherein the reactive material is capable of chemically binding tritium.

36. 36. The heat exchanger system of any one of claims 26 to 35, wherein the reactive material is capable of reacting at least 50% of the tritium exiting the exterior surface of the first conduit.

37. 36. The heat exchanger system of any one of claims 26 to 35, wherein the reactive material is capable of reacting at least 90% of the tritium exiting the exterior surface of the first conduit.

38. 38. The heat exchanger system of any one of claims 26 to 37, further comprising a solid catalyst capable of promoting a reaction between the reactive material and tritium exiting the exterior surface of the first conduit.

39. A heat exchanger system according to any one of claims 26 to 38, wherein the second conduit is thermally coupled to the first conduit by a solid connector.

40. 40. A heat exchanger according to any one of claims 26 to 39, wherein the first conduit, the second conduit and / or the solid connector include a coating on one or more exterior surfaces configured to participate in a reaction with tritium.

41. a plurality of first conduits, at least some of which contain a primary fluid, the primary fluid containing tritium; a plurality of second conduits thermally coupled to the plurality of first conduits, wherein at least one of the plurality of first conduits is thermally coupled to two or more of the plurality of second conduits and / or at least one of the plurality of second conduits is thermally coupled to two or more of the plurality of first conduits; and a sweep gas surrounding the plurality of first conduits and the plurality of second conduits, the sweep gas including tritium originating from the primary fluid; a heat exchanger system including:

42. 42. The heat exchanger system of claim 41, wherein the plurality of second conduits are thermally coupled to the plurality of first conduits by at least one solid connector.

43. The heat exchanger system of any one of claims 41 to 42, wherein the plurality of first conduits and the plurality of second conduits are arranged in an alternating manner with respect to each other.

44. 44. The heat exchanger system of any one of claims 42 to 43, wherein the plurality of first conduits, the at least one solid connector and the plurality of second conduits are arranged in alternating layers.

45. The heat exchanger system of any one of claims 41 to 44, wherein the plurality of first conduits comprises conduits formed within one or more metal sheets.

46. The heat exchanger system of any one of claims 41 to 44, wherein the plurality of second conduits comprises metal tubes.

47. The heat exchanger system of any one of claims 42 to 46, wherein at least one solid connector comprises one or more corrugated metal sheets.

48. 48. The heat exchanger system of any one of claims 41 to 47, wherein the heat exchanger comprises a plurality of unit cells, the unit cells comprising at least one of the plurality of first conduits and at least one of the plurality of second conduits.

49. 49. The heat exchanger system of any one of claims 41 to 48, further comprising a manifold configured to channel the primary fluid to the inlets of the plurality of first conduits and / or to receive the primary fluid from the outlets of the plurality of first conduits.

50. 50. The heat exchanger system of any one of claims 41 to 49, further comprising a manifold configured to channel the secondary fluid to the inlets of the plurality of second conduits and to receive the secondary fluid from the outlets of the plurality of second conduits.

51. A power plant comprising a heat exchanger according to any one of claims 1 to 50.

52. 52. The power plant of claim 51, wherein the power plant is a nuclear fusion power plant.

53. 52. The power plant of claim 51, wherein the power plant is a nuclear fission power plant.

54. 54. The powerplant of any one of claims 51 to 53, wherein the powerplant further comprises a tritium extractor downstream of the heat exchanger system.

55. forming a plurality of first conduits; forming at least one solid connector; forming a plurality of second conduits; stacking the plurality of first conduits, at least one solid connector, and the plurality of second conduits in alternating layers such that the at least one solid connector thermally couples the plurality of first conduits to the plurality of second conduits; and (c) forming a heat exchanger system.

56. 56. The method of claim 55, wherein forming at least one solid connector comprises forming one or more corrugated metal sheets.

57. 57. The method of claim 56, wherein forming one or more corrugated sheets of metal comprises rolling and / or extruding one or more metal sheets.

58. 58. The method of any one of claims 55 to 57, wherein forming the plurality of first conduits comprises forming a plurality of channels on a surface of a first metal sheet and bonding a surface of a second metal sheet to the surface of the first metal sheet to form the enclosed channels.

59. 59. The method of claim 58, wherein the plurality of channels are formed via cutting and / or etching a surface of the first metal sheet.

60. 60. A method according to any one of claims 58 to 59, wherein a surface of the second metal sheet is joined to a surface of the first metal sheet via brazing and / or diffusion welding.

61. The method of any one of claims 55 to 60, wherein forming a plurality of second conduits comprises forming a plurality of metal tubes and / or metal pipes.

62. 62. The method of any one of claims 55 to 61, further comprising joining the stacked alternating layers of first conduits, connectors and second conduits.

63. 63. The method of claim 62, wherein the stacked alternating layers are joined via brazing.

64. passing a primary fluid containing tritium through a first conduit of a heat exchanger; transferring heat from the primary fluid to a secondary fluid contained within a second conduit of the heat exchanger through a connector, the connector thermally coupling an outer surface of the first conduit to an outer surface of the second conduit; flowing a sweep gas around the first conduit, the second conduit, and the connector to remove tritium from the primary fluid and the connector; and a method comprising:

65. 65. The method of claim 64, wherein the sweep gas removes at least 50% of the tritium exiting the exterior surface of the first conduit.

66. 66. The method of any one of claims 64 to 65, wherein the sweep gas removes at least 90% of the tritium exiting the exterior surface of the first conduit.

67. 67. The method of any one of claims 64-66, further comprising reacting the removed tritium with a solid, liquid and / or gaseous reactant to form one or more tritium-containing reaction products.

68. 68. The method of any one of claims 64 to 67, further comprising extracting the removed tritium from the sweep gas.

69. 69. The method of any one of claims 67 to 68, further comprising extracting tritium from one or more tritium-containing reaction products.

70. 70. The method of any one of claims 64 to 69, further comprising recycling the removed tritium to a fusion power plant.

71. The method of any one of claims 64 to 70, wherein the connector is a solid connector.

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