Improvements relating to fusion reactor fuel recovery

Abstract

A cryopump (100) for recovering fuel from off-gas of a nuclear fusion reactor (10) is described. The cryopump (100) includes a chamber configured to receive a gas; a first panel (104) disposed in the chamber and cooled to a first temperature, wherein the first temperature is greater than 20 K; a second panel (106) disposed in the chamber and cooled to a second temperature, wherein the second temperature is in the range of 10 K to 20 K; and a valve configured to isolate the second panel from the first panel. An exemplary cryopump (100) allows a reactor to recover fuel more quickly and reduce operating energy costs.

Description

Technical Field

[0001] The present disclosure generally relates to a technology for treating exhaust gas from a nuclear fusion reactor (such as a tokamak) to achieve rapid recovery and recycling of deuterium and tritium. More specifically, the present disclosure relates to a multi-stage cryopump for use in the technology. Background Art

[0002] Currently, fusion reactors that rely on magnetic confinement (mainly fusion reactors designed based on the tokamak principle) use fusion fuel composed of a mixture of deuterium and tritium (i.e. hydrogen isotopes). A byproduct of the fusion process is helium, which needs to be extracted from the reactor through a suitable exhaust device. Of course, the helium is mixed with unfused deuterium and tritium in the reactor, so extracting the helium also extracts useful reactor fuel (as well as other gases present in the reactor, such as argon, neon and xenon).

[0003] A cryopump is a vacuum pump that works by freezing and adsorbing gases on a cold surface at extremely low temperatures. Existing magnetic confinement reactors typically utilize cryopumps cooled to near 4K to capture most, if not all, of the effluent from the reactor (i.e., helium, deuterium, tritium, and other impurities). For current test systems, the reactor is taken offline at the end of the test, and the cryopumps are then regenerated to recover useful fuel for reuse in the reactor in future experiments (i.e., to recover tritium and deuterium). This process typically takes several hours. Therefore, typical existing reactors are considered non-continuous, and they cannot be easily adapted to continuous operation.

[0004] It should be understood that taking a reactor offline for hours while refueling is undesirable from a commercial energy production perspective, which would rather have the reactor run essentially continuously. One option is to compensate for any lost material by simply adding more tritium (and deuterium) to the reactor, potentially ignoring the need to recapture the fuel. The problem with this approach is that tritium is extremely expensive (currently around $30,000 per gram), and the method requires large quantities of tritium (hundreds of grams). Since tritium is a radioactive material, there are also safety and regulatory issues with storing so much tritium.

[0005] Therefore, it is essential to develop a system that can efficiently and continuously recycle tritium (and, to a lesser extent, deuterium) to enable reactors to operate in a commercial environment and reduce the amount of tritium required. Summary of the invention

[0006] The present invention is defined according to the independent claim, and additional features will be understood from the dependent claims and the description herein.Any embodiments described but not falling within the scope of the claims are merely construed as examples that help to better understand the present invention.

[0007] Exemplary embodiments are provided to address at least some of the difficulties encountered with current magnetic confinement fusion reactors, whether or not such difficulties have been specifically mentioned above or will otherwise be apparent from the discussion herein.

[0008] In a broad sense, the present disclosure relates to providing a technique for separating the exhaust impurities from a tokamak (or other reactor) from the fuel stream so that the fuel can be quickly recovered under high vacuum pressure. Typical recovery cycles are measured in minutes, rather than hours or days for other methods. A cryogenic pump is discussed herein for selectively capturing fuel, deuterium and tritium, i.e., D and T (sometimes referred to herein as DT), and some impurities, while allowing helium and a large amount of protium to be continuously pumped out during the DT cryogenic adsorption cycle. This enables rapid recovery of deuterium and tritium with minimal impurities during operation of the tokamak (reactor), thereby minimizing the inventory of tritium, and the present technology also beneficially reduces cryogenic power consumption. Therefore, the present disclosure represents a key step in achieving continuous operation of a reactor that will be able to overcome the commercial operation barriers inherent in existing test systems (i.e., the inability to recover tritium on a reasonable time scale), thereby achieving commercial energy production.

[0009] In one aspect of the invention, a cryogenic pump for recovering fuel from the exhaust gas of a nuclear fusion reactor is provided. The cryogenic pump includes a chamber configured to receive the exhaust gas, a first panel and a second panel arranged in the chamber, wherein the first panel is cooled to a first temperature greater than 20 Kelvin (more preferably in the range of 30 Kelvin to 80 Kelvin, including the endpoint value), and the second panel is cooled to a second temperature in the range of 10 Kelvin to 20 Kelvin (including the endpoint value). In a preferred arrangement, the gas is directed through the chamber, first passing through the first panel and then passing through the second panel to allow impurities to be deposited on the first panel and DT to be deposited on the second panel.

[0010] The cryopump includes a first valve configured to isolate the second panel from the first panel (by dividing the chamber between the first panel and the second panel in half, isolating the second panel from the reactor exhaust). Advantageously, the second panel can then be regenerated, thereby recovering the DT separately from the impurities in the first panel (effectively, separately from the helium process).

[0011] In one example, the cryopump includes a second valve and a third valve. The second valve and the third valve are configured to isolate the chamber from the outlet and the inlet of the cryopump, respectively. Thus, the second valve isolates the second panel from the helium processing path, and the third valve isolates the first panel to be regenerated from the impurity processing system.

[0012] In another aspect of the present invention, a fusion energy system is provided, comprising a reactor and the above-mentioned cryopump, wherein the reactor comprises an exhaust device suitably connected to the inlet of the cryopump. In one example, the energy system comprises at least two cryopumps, and the second cryopump is also connected to the exhaust device of the reactor.

[0013] In another aspect of the present invention, a method for rapidly recovering fuel from a nuclear fusion energy system is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For a better understanding of the present disclosure, reference will now be made to the accompanying drawings, in which:

[0015] Figure 1 A schematic diagram of the process of fuel recovery in the prior art is shown;

[0016] Figure 2 A schematic diagram of the process of fuel recovery according to the present technology is shown;

[0017] Figure 3 An exemplary cryopump during an adsorption process is shown;

[0018] Figure 4 shows an exemplary cryopump during regeneration; and

[0019] Figure 5 Another exemplary cryopump is shown. DETAILED DESCRIPTION

[0020] At least some of the following exemplary embodiments provide improved techniques for recycling tritium (and deuterium) for fusion reactors.Other advantages and improvements will also be apparent from the discussion herein.

[0021] Figure 1 A simplified flow diagram of a prior art fuel recovery system is shown. Here, a reactor 10 utilizes deuterium and tritium as fusion fuel to produce energy and helium byproduct. A vacuum pump system 12 extracts gas from the reactor 10 through an exhaust. The pump system 12 includes a cryopump that includes adsorption panels cooled to approximately 4K (degrees Kelvin), more specifically, typically in the range of 4.2-4.5K. This temperature is selected because it allows the cryopump to adsorb helium, tritium, deuterium, and other impurities from the exhaust gas. When the reactor 10 is offline, the cryopump adsorption panels are regenerated (i.e., heated) so that the exhaust gas treatment system 14 can separate the materials adsorbed on the cryopump panels. Therefore, the exhaust gas treatment allows fuel recovery 16 because the deuterium and tritium are separated from other materials captured from the exhaust gas. The recovered fuel will typically be stored and then later returned to the reactor 10 by the material injection system 18. The next time the reactor is shut down, the cycle is repeated.

[0022] Figure 2 A schematic diagram of an improved technique for deuterium / tritium fuel recovery for continuous operation of a reactor is shown. The technique is described for exhaust gas, but it should be understood that the technique can be applied to any suitable gas flowing out of the reactor 10. In addition, since deuterium and tritium are the standard fuel mixtures for current fusion reactors, the combination of deuterium and tritium will be mentioned below, but it should be understood that the present technique can be applied to other fuel mixtures containing at least one of deuterium and tritium (primarily tritium, which is generally the more important of the two).

[0023] Similar to Figure 1 , the exhaust gas can be pumped out of the reactor by a suitable vacuum pump system 12. However, the vacuum system 12 here includes a modified cryopump 100 and other vacuum pumps to exhaust at different pressures until atmospheric pressure ( Figure 2 not included). Generally, the improved cryopump 100 is arranged to capture deuterium and tritium from the exhaust gas and separate it from other impurities and helium. The captured deuterium, and more importantly tritium, is then directed from the cryopump 100 to the material injection system 18 without any additional processing. As a result, the fuel can be quickly recovered (box 20) and reinjected into the reactor 10. Here, "quickly" refers to minutes or tens of minutes, while current fuel recovery time scales are up to hours. Beneficially, the reactor 10 using the improved cryopump will only require a low tritium inventory while still allowing the reactor 10 to operate continuously. If the existing test system were used for commercial energy production, the tritium inventory required to operate in a (near) continuous manner would be hundreds of grams; in contrast, the present technology is estimated to require only a few grams of tritium inventory (e.g., 3 to 4 grams).

[0024] Figure 3 and Figure 4 A schematic diagram of an exemplary cryopump 100 is shown. The cryopump 100 includes a chamber 102 into which exhaust gas from the reactor 10 is received, and a first panel 104 and a second panel 106 are both arranged (i.e., disposed) in the chamber 102. As shown, preferably, the first panel 104 and the second panel 106 are each one of the panels in an array of panels placed side by side in the chamber 102 (i.e., located at similar points on the axis of the cryopump 100, where the "X" axis is defined as being substantially parallel to the gas inflow of the cryopump 100). That is, the cryopump 100 may include a first panel array 104' and a second panel array 106', the first panel array 104' including the first panel 104, and the second panel array 106' including the second panel 106. One or more first panels 104 and one or more second panels 106 are arranged separately in the chamber 102.

[0025] One or more first panels 104 are cooled to a first temperature, while one or more second panels 106 are cooled to a second temperature. The first temperature is different from the second temperature so that different substances are adsorbed on one or more first panels 104 / one or more second panels 106, and therefore, the exemplary cryopump 100 can be regarded as a multi-stage cryopump (specifically a two-stage pump). One or more first panels 104 are configured to capture impurities from the exhaust gas, while one or more second panels 106 are configured to capture unused fuel (i.e., DT) from the exhaust gas. In order to promote the adsorption of substances, some (or all) of the panels 104 and 106 can be coated with activated carbon. Other coatings that promote adsorption can be used instead. It should be understood that, in the case of using a panel array, cooling the array to a first temperature or a second temperature means setting a target temperature for the array while allowing some variations in the array (within the target range).

[0026] The one or more first panels 104 are cooled to a temperature greater than 20 K (degrees Kelvin). Such a temperature allows the capture of unwanted impurities from the exhaust gas, but importantly, deuterium and tritium are generally not captured. Preferably, the one or more first panels 104 are cooled to between 30 K and 80 K (inclusive of the end values).

[0027] The one or more second panels 106 are cooled to a temperature between 10 K and 20 K, inclusive. More generally, the one or more second panels 106 are cooled to a lower temperature than the one or more first panels 104. Cooling the one or more second panels 106 to between 10 K and 20 K allows the fuel (i.e., deuterium and tritium) to adsorb onto the second panels.

[0028] It should be appreciated that the panel operating temperatures described are all well in excess of the typical 4K temperatures at which current systems operate cryopumps, and that significant energy gains in efficiency can be achieved compared to such systems.

[0029] Gas flows into the cryopump 100 and the chamber 102 through the inlet 108. In a reactor system, the inlet 108 is therefore appropriately connected to the reactor exhaust (e.g., through a component of the vacuum system 12). The gas flows through the chamber 102 to the outlet 110. As the gas flows through the chamber 102, it first flows through one or more first panels 104 and then flows through one or more second panels 106. This arrangement reduces the amount of impurities deposited on one or more second panels 106, thereby reducing the need for subsequent purification of deuterium / tritium from the second panels 106. Of course, in principle, the panels can be arranged in reverse in the chamber 102. Suitably, it is conceivable that the adsorption panels are connected in parallel during the cryogenic adsorption of fuel and impurities from the exhaust gas.

[0030] The exemplary cryopump 100 is not arranged to capture helium or molecular protium. Doing so would require setting the cryopump panel (or array of panels) to substantially 4K. In principle, such a panel / array of panels could be arranged in the chamber 102 to provide an additional adsorption stage. However, due to the increased energy required to cool a set of panels to capture helium and / or protium, this arrangement is not preferred. Instead, helium and / or protium are pumped out of the cryopump through the outlet 110. In other words, the inlet 108 and outlet 110 are fluidly connected through the chamber 102 so that gas can flow through the cryopump 100, passing through each panel 104, 106. Helium, molecular hydrogen and other impurities (e.g., other gases) are pumped to the plasma exhaust treatment system 22 ( Figure 2 ).

[0031] In a preferred example, the cryopump 100 includes a first valve 112 configured to isolate the one or more second panels 106 from the one or more first panels 104. That is, the first valve 112 includes an open position ( Figure 3 ) and closed position ( Figure 4 ), in the open position, gas flows freely from the inlet 108 through the chamber 102 to the outlet 110, passing through the first panel 104 and the second panel 106; in the closed position, gas is prevented from flowing through the chamber 102, passing through one or more second panels 106 and flowing out of the cryopump 100.

[0032] When the one or more second panels 106 are properly isolated from the exhaust (i.e., when the first valve 112 is closed), the one or more second panels 106 can be regenerated to release the trapped fuel (deuterium and tritium). Regeneration of the one or more second panels 106 includes stopping cooling the second panels to a target temperature and can also include actively heating the one or more panels 106 to heat the panels more quickly and speed up the regeneration process.

[0033] In one example, the regenerated fuel can then be easily delivered to the material injection system 18 and recycled to the reactor 10 via a path involving the outlet 110, and the path is therefore at least partially shared by the vacuum path that previously delivered and extracted helium, but does not pass through the plasma exhaust treatment system 22. That is, when the first valve 112 is closed, the general plasma process 22 can be isolated from the cryopump 100 and the appropriate gas path to the material injection system 18 is opened. This arrangement is preferred due to the simplicity of the design of the exemplary cryopump 100.

[0034] Thus, a reactor system including the exemplary cryopump 100 may be made more efficient by eliminating the need for additional material handling to separate the fuel from helium and other impurities, and may reduce the need for large tritium inventories by returning the tritium quickly to the reactor 10 .

[0035] In addition, one or more first panels 104 may also be regenerated when valve 112 is closed. That is, cooling of one or more first panels 104 may be stopped, and first panels 104 may optionally be actively heated, while one or more second panels 106 are regenerating on the other side of closed valve 112. In other words, panel regeneration may be achieved in parallel, which allows cryopumps and associated systems to operate more efficiently, as compared to series cryopreservation.

[0036] In particular, impurities regenerated from one or more first panels 104 may be suitably delivered from a cryogenic pump to the plasma processing system 22 separately from any delivery route taken by the fuel (e.g., via an appropriate valve / outlet 122, Figure 4 Alternatively, by raising the temperature of the one or more second panels 106 to above 80K during regeneration, the first valve 112 may be opened (after a predetermined period of time, or after a desired amount of fuel recovered from the one or more second panels 106 is measured), and impurities released from the one or more first panels 104 are released from the cryogenic pump 100 through the outlet 110 (and directed to an associated location placed downstream of the cryogenic pump).

[0037] After regeneration of the one or more first panels 104 and the one or more second panels 106 , it will be appreciated that the panels may be re-cooled to the appropriate target temperature, the first valve 112 reopened, and the fuel recovery process restarted.

[0038] In another example, the cryopump 100 includes a second valve 114 configured to isolate the one or more second panels 106 (more generally, the chamber 102) from the outlet 110; it should also be understood that the second valve 114 can be appropriately configured as part of the outlet 110. In other words, the second valve 114 isolates the chamber 102 from the helium outflow system 22.

[0039] More specifically, the second valve 114 includes an open position ( Figure 3 ) and closed position ( Figure 4 ). In the open position, gas flows from the inlet 108 through the chamber 102 to the outlet 110, passing through the first panel 104 and the second panel 106; in the closed position, the second panel 104 is sealed from the outlet 110. Therefore, the combination of the first valve 112 and the second valve 114 creates a sub-chamber 116 within the chamber 102, which is isolated from the rest of the cryopump 100. In other words, the second panel 106 is isolated from the chamber 102.

[0040] In this arrangement, the subchamber 116 including the one or more second panels 106 may be suitably coupled to a dedicated fuel recovery path, such as via the second outlet 118, when the first valve 112 and the second valve 114 are closed and the one or more second panels are being regenerated ( Figure 4 ), the second outlet 118 is suitably opened (via, for example, a suitable valve) when the cryogenic pump 100 is used to recover fuel, but the second outlet 118 is suitably closed when the cryogenic pump 100 is used to recover fuel.

[0041] The cryopump 100 may also include a third valve 120 configured to isolate one or more first panels 104 (more generally, the chamber 102) from the inlet 108; it should also be understood that the third valve 120 may be appropriately configured as part of the inlet 108. In other words, the third valve 120 isolates the chamber 102 (more generally, the cryopump as a whole) from the reactor 10.

[0042] More specifically, the third valve 120 includes an open position ( Figure 3 ) and closed position ( Figure 4 ). In the open position, gas flows from the inlet 108 through the chamber 102 to the outlet 110, passing through the first panel 104 and the second panel 106; in the closed position, the cryopump 100 is sealed from receiving further exhaust gas. Thus, the combination of the first valve 112 and the third valve 120 creates a sub-chamber 122 within the chamber 102, which is isolated from the rest of the cryopump 100. In other words, one or more first panels 104 are isolated from further gas flow.

[0043] The subchamber 122 including the one or more first panels 104 may be suitably coupled to a dedicated impurity handling system via, for example, a third outlet 124 which is suitably opened (e.g., by an appropriate valve) when the first valve 112 is closed (and optionally, when the second valve 114 (if present) is also closed and / or the third valve 120 (if present) is closed), but closed during cryosorption. In this way, when the reactor 10 is operating and the fuel is also regenerated by a separate system, the one or more first panels 104 may be regenerated to release previously trapped impurities from the cryopump 100.

[0044] In another example, one or more first panels 104 may be regenerated by staged deactivation of the cryogenic pump (when saturated), wherein the first valve 112 is closed, one or more second panels 106 are then regenerated to recover fuel, the first valve 112 is opened, and then one or more first panels 104 are regenerated to extract impurities via a suitable system coupled to the outlet 110.

[0045] To facilitate continuous operation of the fusion reactor 10, each valve 112, 114, 120 (if present) may be appropriately controlled by a timer so that the valves 112, 114, 120 are activated at predetermined time intervals. For example, the first valve 112 may be configured to remain open for at least two to three hours of reactor operation, then automatically controlled to close for 20 minutes to allow fuel regeneration, then open and allow the process to repeat. Alternatively, diagnostic equipment may be arranged to monitor the saturation levels of the first panel 104 and the second panel 106, and to initiate regeneration of the panel (starting with closing the relevant valve) based on the determined saturation levels.

[0046] It may also be desirable to provide at least one further exemplary cryopump as part of the vacuum system 12. That is, a second cryopump configured in accordance with the above description may also be connected to the exhaust of the reactor 10. Thus, when the first cryopump is isolated from the exhaust to regenerate fuel (and / or impurities, as desired), the second cryopump may be used to continue processing the exhaust.

[0047] More specifically, when one or more second panels 106 from the first cryogenic pump 100 are isolated from the exhaust (i.e., isolated from the reactor) so that the one or more second panels 106 can be regenerated to recover fuel, the reactor exhaust can be directed to a second cryogenic pump 100, which includes a third panel array consisting of panels 104 and a fourth panel array consisting of panels 106, one or more third panels being configured to capture impurities and one or more fourth panels being configured to capture fuel.

[0048] Fuel may then be regenerated from the second cryogenic pump in the same manner as described above, while the first cryogenic pump is reactivated for fuel capture.

[0049] Figure 5 Another exemplary cryopump 100' is shown, which builds on the previous technology. Here, the exemplary cryopump 100' is provided with additional panels / groups of panels to increase the capture of impurities and non-helium / protium gases (e.g., other reactor gases such as xenon, argon and neon), with the purpose of increasing the purity of deuterium and tritium adsorbed to one or more second panels 106. In such an example, each (group) of panels provided in the cryopump 100 represents an additional adsorption stage. In particular, each (group) of panels can be appropriately set to a different temperature range; preferably, the temperature of each (group) of panels decreases from the first panel 104 to the second (last) panel 106 in the cryopump; that is, the panels in the cryopump have a decreasing temperature gradient. The more panels provided, the more obvious the separation of deuterium and tritium from other impurities; that is, the more adsorption stages provided, the higher the purity of deuterium and tritium on the second panel 106.

[0050] More specifically, the exemplary cryopump 100' includes a plurality of first panels 105, or an array / group of a plurality of first panels, here three (groups) of panels 105a, 105b, 105c spaced apart from each other in the chamber 102 (i.e., separated along the axis of the cryopump 100', here separated along the X-axis). Each of the plurality of first panels 105 is cooled to a temperature greater than 20K; preferably between 30K and 80K (including the endpoint values). Each panel (array) is cooled to a different temperature, and preferably, the temperature of each panel (array) 105a, 105b, 105c in the plurality of first panels 105 decreases as it is farther from the inlet 108 and closer to the second panel 106. For example, the temperature range of the first panel (array) 105a in the plurality of panels can be set to 70K to 80K, the temperature range of the second panel (array) 105b can be set to 50K to 60K, and the temperature range of the third panel (array) 105c can be set to 30K to 40K. In general, it should be understood that any number of panels can be set in the plurality of first panels 105, as long as each panel (array) is set to a different temperature. In addition, as shown, the plurality of first panels 105 are arranged in the chamber 102 before the first valve 112, so that the plurality of first panels 105 can be appropriately isolated from the second panel 106.

[0051] It should also be appreciated that in this example, the operation of the one or more second panels 106 and the remainder of the cryopump 100 ′ is substantially the same as described above with respect to the example cryopump 100 .

[0052] In summary, exemplary embodiments of a multi-stage cryogenic pump that facilitates fuel recovery from fusion reactor exhaust have been described herein. The described exemplary embodiments provide an improved technique that facilitates continuous operation of the reactor: an important consideration for commercial energy production. In addition, the exemplary embodiments reduce the energy requirements for fuel recovery compared to typical techniques.

[0053] The exemplary cryopump and auxiliary systems can be manufactured industrially. From the discussion herein, the industrial applicability of the exemplary embodiments will become clear. In addition, the described exemplary embodiments are easy to manufacture and easy to use.

[0054] While preferred embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made thereto without departing from the scope of the invention as defined in the claims.

[0055] Please note that all papers and documents related to this application, filed concurrently with or prior to this specification, are open to public inspection together with this specification, and the contents of all these papers and documents are incorporated herein by reference.

[0056] All features disclosed in this specification and / or all steps of any method or process so disclosed may be combined in any way, except where at least some of these features and / or steps exist in a mutually exclusive combination.

[0057] Unless otherwise expressly stated, each feature disclosed in this specification can be replaced by an alternative feature used for the same, equivalent or similar purpose. Therefore, unless otherwise expressly stated, each feature disclosed is only an example in a series of equivalent or similar features.

[0058] The invention is not limited to the details of the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification, or to any novel step or any novel combination of steps of any method or process disclosed in this specification.

Claims

1. A cryogenic pump for recovering fuel from the exhaust gas of a nuclear fusion reactor, comprising: a chamber configured to receive a gas; a first panel, the first panel being arranged in the chamber and cooled to a first temperature, wherein the first temperature is greater than 20K; a second panel disposed in the chamber and cooled to a second temperature, wherein the second temperature is in a range of 10 K to 20 K, inclusive; and A first valve is configured to isolate the second panel from the first panel.

2. The cryopump according to claim 1, wherein: The first temperature is in the range of 30K to 80K, inclusive.

3. The cryopump according to claim 1 or 2, wherein: The cryopump is configured to direct gas through the chamber, first through the first faceplate and then through the second faceplate.

4. A cryopump according to any one of the preceding claims, wherein: The first panel is one panel in an array of panels that is cooled to the first temperature.

5. A cryopump according to any one of the preceding claims, wherein: The second panel is one panel in an array of panels that is cooled to the second temperature.

6. A cryopump according to any one of the preceding claims, wherein: The first panel and the second panel, and suitably arrays of first panels and arrays of second panels, are coated with activated carbon.

7. A cryopump according to any one of the preceding claims, further comprising at least one additional panel or array of panels spaced apart from the first panel and cooled to a temperature greater than 20 K different from the first temperature.

8. The cryopump according to claim 7, wherein: The first panel and at least one additional panel are arranged to provide a decreasing temperature gradient towards the second panel.

9. The cryopump according to any one of the preceding claims, further comprising a second valve configured to isolate the chamber from an outlet of the cryopump, and wherein: The second panel is disposed in the chamber between the first valve and the second valve.

10. The cryopump of claim 9, further comprising a third valve configured to isolate the chamber from an inlet of the cryopump, and wherein: The first panel is disposed in the chamber between the first valve and the third valve.

11. A cryopump according to any one of the preceding claims, wherein: The first valve is configured to be activated at predetermined time intervals, and when the second valve and the third valve are present, the second valve and the third valve are configured to be activated at predetermined time intervals.

12. A nuclear fusion energy system, comprising: A reactor including an exhaust device coupled to a cryogenic pump; The cryogenic pump comprises: an inlet coupled to the exhaust to receive gas from a fusion reactor; an outlet, the outlet being in fluid communication with the inlet through the chamber, the outlet providing an outflow passage for gas from the cryopump; a first panel, the first panel being arranged in the chamber and cooled to a first temperature, wherein the first temperature is greater than 20K; a second panel disposed in the chamber and cooled to a second temperature, wherein the second temperature is in a range of 10 K to 20 K, inclusive; and A first valve is configured to isolate the second panel from the first panel.

13. The nuclear fusion energy system according to claim 12, wherein: The cryopump is a first cryopump of at least two cryopumps arranged in a system, and wherein an inlet of a second cryopump of the at least two cryopumps is coupled to an exhaust of the reactor.

14. The nuclear fusion energy system according to claim 12 or 13, wherein: The first cryopump and, where present, the second cryopump are configured to include any of the features of any of claims 2 to 11.

15. A method for rapidly recovering fuel from a nuclear fusion reactor, the fuel comprising at least one of deuterium and tritium, the method comprising: directing exhaust gas from the reactor through a first cryopump panel at a first temperature cooled to a temperature greater than 20 K to adsorb impurities in the exhaust gas onto the first panel; then directing the exhaust gas through a second cryopump faceplate cooled to a second temperature between 10 K and 20 K to adsorb at least one of deuterium and tritium onto the second faceplate; and The second panel is isolated from the exhaust of the reactor by a first valve, and the second panel is regenerated to recover at least one of deuterium and tritium.

16. The method according to claim 15, wherein: Regenerating the second panel to recover at least one of deuterium and tritium further includes pumping the recovered at least one of deuterium and tritium back into the fusion reactor.

17. The method according to claim 15 or 16, wherein: When the second panel is isolated from the exhaust gas, the method further comprises: directing exhaust gas from the reactor through a third cryopump panel at a first temperature cooled to a temperature greater than 20 K to deposit impurities in the exhaust gas onto the third panel; and The exhaust gas is then directed through a fourth cryopump faceplate that is cooled to a second temperature between 10 K and 20 K to deposit at least one of deuterium and tritium onto the fourth faceplate.

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