Plasma-facing component

Abstract

A plasma-facing component comprising: an armour layer (101); and a heat sink (201) outboard of and in thermal contact with the armour layer (101); wherein: the heat sink (201) comprises: an impingement surface (211), and a jet array element (220) separated from the impingement surface (211) by a plenum space (231), the jet array element (220) comprising: (a) a first plurality (221) of jet inlet openings for gas jet impingement cooling of the impingement surface (211); and a second plurality of jet inlet openings (222) for gas jet impingement cooling of the impingement surface (211); and wherein the jet array element (220) further comprises a baffle (223) defining a shared outlet from the plenum space (231) for gas from the first and second pluralities of jet inlet openings (221, 222); or (b) a first plurality of jet inlet openings (221) for gas jet impingement cooling of the impingement surface (211); and wherein the jet array element (220) further comprises a baffle (223) defining first and second outlets from the plenum space (231), the first and second outlets from the plenum space (231) shared by gas introduced to the plenum space (231) from the firstly plurality of jet inlet openings (221). A plate type plasma-facing component, and corresponding nuclear fusion power system are also disclosed.

Description

PLASMA-FACING COMPONENTField of the Invention

[0001] The present invention relates generally to plasma-facing components for a nuclear fusion reactor. More specifically, the disclosure is concerned with improving cooling of plasma-facing components.Background

[0002] Designing plasma-facing components in a nuclear fusion reactor that relies on magnetic confinement of plasma requires consideration of the plasma edge processes, together with the material properties of the component. Of particular concern, in terms of material properties of the plasma-facing component, is how the plasma-facing component deals with a high thermal load. As well as the thermal load in ramp up, steady state, and ramp down operations of the fusion reactor, there is a particular challenge in dealing with high heat flux should plasma instability lead to a thermal shock load being applied to the plasma-facing component. Indeed, limiter plasma-facing components specifically are used, with adaptations that are intended to deal with the effects of plasma contact.

[0003] In addition to the design constraints resulting from the expected thermal loads, operational constraints relating to other features of the fusion reactor are also relevant to the design of plasma-facing components. For example, the overall dimensions of the fusion reactor, and the design of heat transfer systems for maintaining operation of the fusion reactor and extracting useable energy from the fusion reactor.

[0004] At present, such heat transfer systems are complex, typically having a large number of joints and other failure points which require continuous maintenance. In addition, there may be conflicting requirements from different systems in the fusion reactor to be as close as possible to the plasma, for efficient overall operation. Historically there has been a trade-off between systems. Naively one might say that the reactor surround simply be made as large as necessary to accommodate all of the various competing systems, however it will be appreciated that space is at a premium in the context of delivering commercially viable energy.

[0005] It is thus highly desirable to seek improvements to the way in which the plasmafacing components are designed, in order to enable better holistic fusion reactor design. It is desirable to enable effective thermal management of the plasma-facingcomponents without unduly increasing the radial dimension needed for the components, or requiring exotic alloys for the heat transfer components, while avoiding other space / size compromises associated with a liquid cooling strategy for plasmafacing components.Summary

[0006] The present invention is defined according to the independent claims. Additional features will be appreciated from the dependent claims and the description herein. Any embodiments which are described but which do not fall within the scope of the claims are to be interpreted merely as examples useful for a better understanding of the invention.

[0007] The example embodiments have been provided with a view to addressing at least some of the difficulties that are encountered with current approaches to designing plasma-facing components, whether those difficulties have been specifically mentioned above or will otherwise be appreciated from the discussion herein. In particular, the example embodiments aim to improve thermal performance of the plasma-facing component, such as without requiring the use of exotic alloys and such that a gas cooling strategy becomes viable, and while managing component count and complexity needed in the elements that supply cooling gas over a relatively large plasma-facing surface area.

[0008] In a first aspect of the invention there is provided a plasma-facing component comprising: an armour layer 101; and a heat sink outboard of and in thermal contact with the armour layer 101; wherein: the heat sink comprises: an impingement surface, and a jet array element separated from the impingement surface by a plenum space, the jet array element comprising: a first plurality of jet inlet openings for gas jet impingement cooling of the impingement surface; and a second plurality of jet inlet openings for gas jet impingement cooling of the impingement surface; and wherein the jet array element further comprises a baffle defining a shared outlet from the plenum space for gas from the first and second pluralities of jet inlet openings.

[0009] In a related aspect of the invention there is provided a plasma-facing component comprising: an armour layer; and a heat sink outboard of and in thermal contact with the armour layer; wherein: the heat sink comprises: an impingement surface, and a jet array element separated from the impingement surface by a plenum space, the jet array element comprising a first plurality of jet inlet openings for gas jet impingement coolingof the impingement surface; and wherein the jet array element further comprises a baffle defining first and second outlets from the plenum space, the first and second outlets from the plenum space shared by gas introduced to the plenum space from the firstly plurality of jet inlet openings. To deal with the high heat flux through the plasma-facing component, a significant pumping power is required to deliver sufficient gas for the gas jet impingement cooling. Furthermore, to achieve relatively uniform heat transfer from the impingement surface, gas jet impingement techniques typically employ a high density of jet inlets, which also increases the required pumping power for a given area. The use of pin fins has been determined to be beneficial in heat transfer performance when convective resistance is much greater than conductive resistance for the heat sink. As such, the pin fins make a significant difference for heat sinks comprising a highly conductive material, such as CuCrZr, at the impingement surface. In addition, it has been determined that the mechanical properties of CuCrZr alloys allow the heat sink to be relatively thin, thus decreasing the conductive resistance and further contributing to the effectiveness of the pin fins in increasing heat transfer performance. The gas cooling approach as described takes full advantage of properties of CuCrZr, while avoiding the issues which may arise from liquid-gas phase change cooling, such as film-boiling, by direct impingement of the gas jets onto the CuCrZr material of the impingement surface

[0010] In a related aspect of the invention there is provided a plasma-facing component comprising: an armour layer; and a heat sink outboard of and in thermal contact with the armour layer; wherein: the heat sink comprises: an impingement surface, and a jet array element separated from the impingement surface by a plenum space, the jet array element comprising:(a) a first plurality of jet inlet openings for gas jet impingement cooling of the impingement surface; and a second plurality of jet inlet openings for gas jet impingement cooling of the impingement surface; and wherein the jet array element further comprises a baffle defining a shared outlet from the plenum space for gas from the first and second pluralities of jet inlet openings; or(b) a first plurality of jet inlet openings for gas jet impingement cooling of the impingement surface; and wherein the jet array element further comprises a baffle defining first and second outlets from the plenum space, the first and second outlets from the plenum space shared by gas introduced to the plenum space from the firstly plurality of jet inlet openings.

[0011] In a related aspect, the jet array element comprises both (a) and (b) above.

[0012] In comparison to plasma-facing components made up of individual unit-cells of armour and an associated integrated individual heat sink, sharing outlets for the plenum space allows a significant reduction in the number of manifolding and structural components, and in the number of associated joints needed therebetween. Thus, a relatively large plasma-facing component can be more-readily achieved with lower complexity, and lower maintenance requirements. Furthermore, meeting design constraints relating to materials used in the plasma-facing component, and the radial thickness dimension between the inboard and outboard sides of the plasma-facing component may also be facilitated. The term inboard is used to mean the side of the plasma-facing component that is closest to the plasma, or a direction toward the plasma, in use. Correspondingly, the term outboard has the opposite sense. It will be understood that the plasma facing component may face toward the centre of a toroidal fusion reactor, or toward the exterior, according to its arrangement in the plasma chamber, and that each of these orientations may comprise an inboard or an outboard direction according to the positioning of the plasma-facing component.

[0013] In one example, the plenum space extends along the length of the plasmafacing component. In one example, the first plurality of jet inlet openings is distributed along the length of the plasma-facing component. In one example, the second plurality of jet inlet openings is distributed along the length of the plasma-facing component. In one example, the shared outlet extends along the length of the plasma-facing component.

[0014] In one example, the plenum space, and shared outlet therefrom, together with the baffle comprise an internal manifolding arrangement for gas movement through the heat sink. In one example, the plenum space defines an unobstructed volume for the delivery of cooling gas from the jet inlet openings onto the impingement surface. In one example, the plenum space defines an unobstructed volume for the removal of cooling gas from the impingement surface to the shared outlet.

[0015] In one example, the jet inlet openings of the first plurality of jet inlet openings are arranged in a linear array, such as at constant spacing from one another. In one example, the jet inlet openings of the second plurality of jet inlet openings are arranged in a linear array, such as at constant spacing from one another. In one example, the first plurality of jet inlet openings is arranged in parallel alignment with the secondplurality of jet inlet openings. In one example, the first plurality of jet inlet openings is laterally offset from the second plurality of jet inlet openings.

[0016] In one example, jet inlet openings of the first plurality of jet inlet openings are aligned midway between jet inlet openings of the second plurality of jet inlet openings. In one example, jet inlet openings of the second plurality of jet inlet openings are aligned midway between jet inlet openings of the first plurality of jet inlet openings.

[0017] In one example, the jet array element comprises a third plurality of jet inlet openings for gas jet impingement cooling of the impingement surface; and wherein the baffle defines a shared outlet from the plenum space for gas from the first and third pluralities of jet inlet openings.

[0018] In one example, the jet inlet openings of the third plurality of jet inlet openings are arranged in a linear array, such as at constant spacing from one another. In one example, the third plurality of jet inlet openings is arranged in parallel alignment with the first plurality of jet inlet openings. In one example, the third plurality of jet inlet openings is arranged in parallel alignment with the second plurality of jet inlet openings. In one example, the third plurality of jet inlet openings is laterally offset from the first plurality of jet inlet openings. In one example, the third plurality of jet inlet openings is laterally offset from the second plurality of jet inlet openings.

[0019] In one example, jet inlet openings of the third plurality of jet inlet openings are aligned midway between jet inlet openings of the first plurality of jet inlet openings. In one example, jet inlet openings of the first plurality of jet inlet openings are aligned midway between jet inlet openings of the third plurality of jet inlet openings. In one example, the jet inlet openings of the second and third pluralities of jet inlet openings are aligned midway between jet inlet openings of the first plurality of jet inlet openings. In one example, the jet inlet openings of the first and second pluralities of jet inlet openings divide the impingement surface into a plurality of equilateral triangles, such as a plurality of identically sized equilateral triangles, with a jet inlet opening at each corner thereof. In one example, the jet inlet openings of the first and third pluralities of jet inlet openings divide the impingement surface into a plurality of equilateral triangles, such as a plurality of identically sized equilateral triangles, with a jet inlet opening at each corner thereof.

[0020] In one example, the jet inlet openings are arranged opposite the impingement surface, such that jets emitted from the jet inlet openings perpendicular to the impingement surface. In one example, the impingement surface is generally planar. In one example, the jet inlet openings are arranged such that jets emitted therefrom are aligned parallel to an inboard-outboard axis. In one example, the jet inlet openings in each are arranged such that jets emitted therefrom are aligned in parallel relation to one another.

[0021] In one example, the jet array element is supported by one or more structural ribs, for example the jet array element is supported between two structural ribs.

[0022] In one example, the structural ribs are integrally formed with the jet array element.

[0023] In one example, the structural ribs run the length of the plasma-facing component.

[0024] In one example, the baffle at least partially bounds an inlet gas delivery volume for the jet array element, the inlet gas delivery volume defined between an inlet manifold for receiving cooling gas, and jet openings of the jet array element. In one example, the baffle and / or one or more structural ribs that support the jet array element bound the inlet gas delivery volume for the jet array element, the inlet gas delivery volume defined between an inlet manifold for receiving cooling gas, and jet openings of the jet array element. In one example, the cross section of the inlet gas delivery volume decreases with distance along the inlet gas delivery volume, such as with distance from the inlet manifold. In one example, the cross section of the inlet gas delivery volume decreases with distance along the inlet gas delivery volume, such as with distance from the inlet manifold, by reduction in its inboard-outboard depth. In one example, the inlet gas delivery volume tapers from the inlet manifold, down along the length of the inlet gas delivery volume.

[0025] In one example, the baffle at least partially bounds an outlet gas exhaust volume for the jet array element, the outlet gas exhaust volume defined between the plenum space and an exhaust manifold for receiving used cooling gas. In one example, the baffle and / or one or more structural ribs that support the jet array element bound the outlet gas exhaust volume for the jet array element, the outlet gas exhaust volume defined between the plenum space and an exhaust manifold for receiving cooling gas.In one example, the cross section of the outlet gas exhaust volume decreases with distance along the gas delivery volume, such as distance toward the exhaust manifold. In one example, the cross section of the outlet gas exhaust volume decreases with distance along the gas delivery volume, such as distance toward the exhaust manifold, by reduction in its inboard-outboard depth. In one example, the inlet gas delivery volume tapers toward the exhaust manifold, down along the length of the outlet gas exhaust volume.

[0026] In one example, the baffle separates the inlet gas delivery volume from the outlet gas exhaust volume. In one example, the baffle separates the inlet gas delivery volume from the outlet gas exhaust volume, such that the change in cross section in one is reflected by the change in cross section of the other, such as a change in cross section along the respective lengths thereof.

[0027] In one example, the baffle defines a shared outlet from the plenum space for gas from the first and second pluralities of jet inlet openings, the shared outlet including the shared gas exhaust volume.

[0028] In one example, the baffle defines a shared inlet to the plenum space for inlet gas supplied to the first and second pluralities of jet inlet openings, the shared inlet including the shared inlet gas delivery volume.

[0029] In one example, in cross section the jet array element comprises a plurality of jet inlet openings inboard, with the baffle extending in an outboard direction to define a side wall of the shared outlet, for example extending in an outboard direction on one side of, or both sides of the plurality of jet inlet openings to define side walls of the outlet gas exhaust volume.

[0030] In one example, in cross section the jet array element comprises a plurality of jet inlet openings inboard, with the baffle extending in an outboard direction to define a side wall of a shared inlet, for example extending in an outboard direction on one side of, or both sides of the plurality of jet inlet openings to define side walls of the gas delivery volume.

[0031] In one example, in cross section the jet array element defines an alternating arrangement of inlet gas delivery volume and outlet gas exhaust volume, by way of the baffle side wall(s), or by way of the baffle side wall(s) and one or more structural ribs.

[0032] In one example, in cross section the jet array element comprises a boustropedal form, with the baffle running back and forth between one or more pluralities of jet inlet openings inboard, and the boundary of the inlet gas delivery volume from the outlet gas exhaust volume outboard. In one example, the jet array element comprises one more, or one less, pluralities of jet inlet openings inboard than there are boundaries separating the inlet gas delivery volume from the outlet gas exhaust volume outboard, between baffle side walls. In one example, the jet array element comprises an even number of pluralities of jet inlet openings inboard, and an odd number of boundaries separating the inlet gas delivery volume from the outlet gas exhaust volume outboard, between baffle side walls. In one example, the jet array element comprises an odd number of pluralities of jet inlet openings inboard, and an even number of boundaries separating the inlet gas delivery volume from the outlet gas exhaust volume outboard, between baffle side walls. In one example, these number are three and four, or from the other point of view four and three.

[0033] In one example, the plasma-facing component comprises a plate-type plasmafacing component. In one example, the plate type plasma-facing component comprises a plurality of plasma-facing components as herein described, formed integrally with each other.

[0034] In one example, the plasma-facing component comprises a plate-type plasmafacing component with an inboard-outboard depth dimension of less than 150mm, for example less than 100mm, such as 50mm. In one example, the plasma-facing component comprises a plate-type plasma-facing component with a length dimension of greater than 100mm, for example greater than 250mm, such as 500mm. In one example, the plasma-facing component comprises a plate-type plasma-facing component with a width dimension of greater than 100mm, for example greater than 150mm, such as 250mm.

[0035] In one example, the plasma-facing component comprises a plate-type plasmafacing component of generally rectangular form. In one example, the plasma-facing component comprises a plate-type plasma-facing component with reflective symmetry, internally, either side of a plane that bisects the long sides thereof.

[0036] In one example, the structural ribs divide the plate type plasma-facing component into a plurality of units, each unit comprising the features of a plasma-facing component as herein described. In one example, the structural ribs divide the platetype plasma-facing component into a plurality of like units. In one example, the like units are supplied from a shared primary input for cooling gas. In one example, the like units discharge used cooling gas from a shared primary exhaust. In one example, the shared primary input runs transverse to the structural ribs, for example passing adjacent to the ends thereof, for example transverse thereto. In one example, the units demonstrate reflective symmetry, internally, either side of a plane that bisect them and is aligned with an inboard-outboard axis.

[0037] In one example, the shared primary exhaust runs transverse to the structural ribs, for example passing adjacent to the ends thereof, for example transverse thereto. In one example, the shared primary input and shared primary exhaust are located at opposite ends of the structural ribs.

[0038] In one example, the shared primary exhaust communicates used cooling gas to an overall plate outlet. In one example, the shared primary input receives cooling gas from an overall plate inlet. In one example, the plate type plasma-facing component comprises a single overall plate inlet. In one example, the plate type plasma-facing component comprises a single overall plate outlet. In one example, the plasma-facing component is helium cooled, and the plasma-facing component comprises a connection to a pressurised supply of cooling helium gas, and a connection to a helium gas collecting exhaust. In one example, said connection(s) may comprise the single overall plate outlet and / or single overall plate inlet.

[0039] In one example, the jet array element is formed of copper-chromium-zirconium alloy material. In one example, the jet array element is formed of copper-chromium-zirconium alloy material such as to present a CuCrZr surface for impingement, such as an uncoated or otherwise uncovered surface.

[0040] In one example, the plasma-facing component comprises a heat transfer layer between the armour layer and the heat sink. In one example, the heat transfer layer comprises a copper layer, such as a low-oxygen copper layer. In one example, the heat transfer layer is bonded to the armour layer, and / or to the heat sink. In one example, the heat transfer layer is in intimate thermal contact with the armour layer and the heat sink. In one example, the heat transfer layer provides a thermal bridge between the armour layer and the heat sink.

[0041] In one example, the armour layer comprises a plurality of armour tiles. In one example, the armour layer comprises a tungsten layer, or a layer comprising a tungsten alloy.

[0042] In one example, the impingement surface is provided on an insert that is bonded to the heat sink. This simplifies manufacture of the component. In one example, the impingement surface is formed integrally with the pressure boundary of the heat sink.

[0043] In one example, wherein the impingement surface comprises a copper-chromium-zirconium alloy material. In one example, a plurality of pin fins is provided on the impingement surface. In one example, the jet array element is formed of copper-chromium-zirconium alloy material such as to present a CuCrZr surface for impingement, such as an uncoated or otherwise uncovered surface.

[0044] In a related aspect of the invention there is provided a nuclear fusion power system comprising a vacuum vessel within which a plasma is produced, and a plasmafacing component as herein described.Brief Description of the Drawings

[0045] For a better understanding of the present disclosure reference will now be made by way of example only to the accompanying drawings, in which:FIG. 1 shows a perspective view of an example plate-type plasma-facing component, with the inboard, plasma-facing surface visible toward the top;FIG. 2 shows cross sectional view within the plasma-facing component of FIG. 1, looking generally down the length thereof, the cross section taken generally across the width thereof roughly one third from the near end ;FIG. 3 shows a perspective sectional view of another plasma-facing component, section at first and second symmetry planes thereof;FIG. 4 shows a cross-sectional view of the plasma-facing component of FIG. 3, sectioned through a plurality of jet inlet openings, to illustrate a baffle sidewall, a plenum space as well as a shared primary input for cooling gas and a shared primary exhaust;FIG. 5 shows a further cross-sectional view of the plasma-facing component of FIG. 3, sectioned to illustrate a structural rib, as well as a shared primary input for cooling gas and a shared primary exhaust;FIG. 6 shows four example sections of plasma-facing component, illustrating the material arrangement of an example embodiment, and four different arrangements of jet array element; andFIG. 7 shows, schematically, an example arrangement for the jet array element, in both top and side views, when the jet array element comprises first, second and third linear arrays of jet inlet openings.Detailed Description

[0046] At least some of the following example embodiments provide an improved design and construction for plasma-facing components, considering the thermal and structural requirements for limiters in a nuclear fusion reactor that operates using magnetically confined plasma. Other advantages and improvements may also be apparent from the discussed embodiments herein.

[0047] FIG. 1 shows a plasma-facing component 1. The plasma-facing component 1 comprises a plate-type limiter for a plasma fusion reactor, the plasma-facing component 1 comprising: an armour layer 101; and a heat sink 201 outboard of and in thermal contact with the armour layer 101. In use, the armour layer 101 faces the plasma, which is located inboard of the plasma-facing component 1. Since the plasma has an extremely high temperature, in use a significant heat flux is incident on, and correspondingly significant heat energy passes through the plasma-facing component 1. To resist this thermal stress, the armour layer 101 is made up of a plurality of tungsten armour tiles, which are of high melting point. The individual tiles are not separately labelled in the Figures, for the sake of simplicity, but as can be seen they are generally square shaped. In other embodiments, different tile materials and geometries are contemplated for the armour layer 101. For example, beryllium tiles, or rectangular tiles.

[0048] The plasma-facing component 1 is adapted so that its shape conforms, at least in the sense of being curved in the same directions, as the shape of the plasma boundary that it is to face in use. The curvature is achieved at a micro scale with slightly different thickness armour tiles, armour tiles of different thickness across their area, orthe armour tile seating on the heat sink 201 at an angle to the heat sink 201 (or a combination of two or three of these adaptations). This improves the effectiveness of the plasma-facing component 1 in terms of resistance to the effects of the plasma, in use, and furthermore makes it easier to align a plurality of plasma-facing components accurately with respect to one another even when the plasma-facing components are of a larger plate-type construction.

[0049] To cope with the heat stress on the plasma-facing component 1, the heat sink 201 is arranged in thermal contact with the armour layer 101, and configured to carry heat from the plasma-facing component 1. In the embodiments shown, the heat sink 201 uses a gaseous cooling medium. The gaseous medium may be provided in the form of helium gas, which provides jet impingement cooling for an impingement surface 211 made of CuCrZr and which is provided with a plurality of pin fins thereon. The pin fins of CuCrZr material are directly exposed to gaseous cooling medium, in use.

[0050] The heat sink 201 of the plasma-facing component 1 provides integrated, internal manifolding for the gaseous cooling medium, described in detail below and visible to different degrees in the various embodiments shown in FIG. 2 through FIG. 7.

[0051] The heat sink 201 comprises an impingement surface 211, and a jet array element 220 separated from the impingement surface 211 by a plenum space 231 231. In use cooling gas, such as high-pressure helium, is delivered from the jet array element 220, through the plenum space 231 and impinges on the impingement surface 211, providing a cooling effect for the impingement surface 211.

[0052] A first plurality of jet inlet openings 221 for gas jet impingement cooling of the impingement surface 211; and a second plurality of jet inlet openings 222 for gas jet impingement cooling of the impingement surface 211 are provided in the jet array element 220. The jet array element 220 further comprises a baffle 223 defining a shared outlet from the plenum space 231 for gas from the first and second pluralities of jet inlet openings 221, 222. The baffle 223 may also be referred to as an inlet / outlet divider. The shared outlet lies outwardly and between the first and second pluralities of jet inlet openings 221, 222, between side wall portions of the baffle 223, labelled as 224 and 225.

[0053] In comparison to plasma-facing components made up of individual unit-cells of armour and an associated integrated individual heat sink 201, sharing outlets for theplenum space 231 allows a significant reduction in the number of manifolding and structural components, and in the number of associated joints needed therebetween. Thus, a relatively large plasma-facing component can be more-readily achieved with lower complexity in assembly, and lower maintenance requirements.

[0054] For example, the plate-type plasma-facing component 1 is relatively large, with example dimensions for length, width, and depth of 500mm, 250mm and 50mm. In the other Figures, further representative example dimensions are provided, as are example material choices and other explanatory remarks and labels.

[0055] FIG. 2 further shows that the baffle 223 further defines first and second outlets from the plenum space 231 , the first and second outlets from the plenum space 231 shared by gas introduced to the plenum space 231 from the firstly plurality of jet inlet openings. That is, in FIG. 2, outwardly extending portions of the baffle 223 that are located on either side of the

[0056] Referring now to FIG. 3 though FIG. 5, it will be appreciated that the plenum space 231 extends along the length of the plasma-facing component 1, as do each of the pluralities of jet inlet openings and furthermore as does the shared outlet.

[0057] In the examples shown, the plenum space 231, and shared outlet therefrom, together with the baffle 233 comprise an internal manifolding arrangement for gas movement through the heat sink 201. The plenum space 231 defines an unobstructed volume for the delivery of cooling gas from the jet inlet openings onto the impingement surface 211 and defines an unobstructed volume for the removal of cooling gas from the impingement surface 211 to the shared outlet, in the sense that the cooling gas is not constrained in channels, or by other macro features of the impingement surface 211. The jet inlet openings 221 are arranged opposite the impingement surface 211, such that jets emitted from the jet inlet openings 221 perpendicular to the impingement surface 211. The impingement surface 211 is generally planar and the jet inlet openings 221 are arranged such that jets emitted therefrom are aligned generally parallel to an inboard-outboard axis, and generally in parallel to one another.

[0058] T o give scalability, the jet array element 220 is supported between two structural ribs 240, with a plurality of unit elements as described formed alongside one another, between the structural ribs 240. The structural ribs 240 run the length of the plasma-facing component 1, and further contribute to gas distribution within the heat sink 201, both within the unit elements, and between them.

[0059] The baffle 223 at partially bounds an inlet gas delivery volume for the jet array element 220, the inlet gas delivery volume defined between an inlet manifold 250 for receiving cooling gas, and jet openings of the jet array element 220. The baffle 223 and / or one or more structural rib 240 that support the jet array element 220 bound the inlet gas delivery volume for the jet array element 220, the inlet gas delivery volume defined between an inlet manifold 250 for receiving cooling gas, and jet openings of the jet array element 220. As is visible in FIG. 3 and FIG. 4, the cross section of the inlet gas delivery volume decreases with distance along the inlet gas delivery volume, decreasing with distance from the inlet manifold 250. This tapered arrangement helps with even distribution of cooling gas through the jets 231.

[0060] Furthermore, the baffle 223 bounds an outlet gas exhaust volume for the jet array element 220, the outlet gas exhaust volume defined between the plenum space 231 and an outlet manifold, or exhaust manifold 260 for receiving used cooling gas. The baffle 223 and structural ribs 240 that support the jet array element 220 bound the outlet gas exhaust volume for the jet array element 220, with the outlet gas exhaust volume defined between the plenum space 231 and an outlet manifold 260.

[0061] As will be appreciated, the baffle 223 separates the inlet gas delivery volume from the outlet gas exhaust volume, such that the change in cross section in one is reflected by the change in cross section of the other along the respective lengths thereof, with the cross section of the inlet gas delivery volume decreasing along its length, to even out delivery of gas, and the outlet gas exhaust volume also decreasing along its length to concentrate the flow of exhaust used cooling gas. FIG. 3 illustrates the cooling gas flow before issuing from the jet array element 220 (mid tone), as it is jetted therefrom (light tone) and as it is collected and passed out of the exhaust manifold 260.

[0062] In the first example shown in FIG. 6, the baffle 223 defines a shared outlet from the plenum space 231 for gas from first, second and third pluralities of jet inlet openings 221, 222, 223, with shared outlets therebetween, communicating with the respective shared gas exhaust volume. In this embodiment, the structural ribs 240 contribute to gas manifolding on the inlet side, but on the outlet side, the baffle 233 is primarily responsible for this function.

[0063] The other examples in FIG. 6 show different arrangements of jet array elements 220, with various shapes of baffle 223 defining shared inlets to the plenum space 231 for inlet gas supplied to the first and second pluralities of jet inlet openings, inlet including the shared inlet gas delivery volume. In the examples of FIG. 6, in cross section the jet array elements 220 define an alternating arrangement of inlet gas delivery volume and outlet gas exhaust volume, by way of the baffle 223 side wall(s), or by way of the baffle 223 side wall(s) and one or more structural rib 240. Different jet inlet openings, for example different spacings and sizes, are also provided, according to the specified cooling performance required of the plasma-facing component 1.

[0064] As will be appreciated from FIG. 2 through FIG. 6, the structural ribs 240 divide the plate type plasma-facing component into a plurality of units, each unit comprising the features of a plasma-facing component as herein described. The structural ribs 240 suitably divide the plate type plasma-facing component 1 into a plurality of like units, which are supplied from shared inlet manifold 250 for cooling gas, which may also be referred to as a shared primary inlet, and discharge used cooling gas from a shared outlet manifold 260, which may be referred to as a shared primary exhaust. The shared primary input 250 runs transverse to the structural rib 240, passing adjacent to the ends thereof, and running transverse thereto. The shared primary input and shared primary exhaust are located at opposite ends of a structural rib 240 in each unit.

[0065] The shared primary exhaust communicates used cooling gas to an overall plate outlet, which is not shown. The shared primary input receives cooling gas from an overall plate inlet 205 identified in FIG. 2. Said overall plate inlet and outlet facilitate connection to a gas supply and exhaust system. In various embodiments concentric overall inlet and outlets may be used to reduce the effect of thermal stresses, and these may be located centrally, or at a corner, or edge of the plate-type plasma-facing component 1.

[0066] Figure 6 show firstly the material components of the plasma-facing component 1. That is, the armour layer 101 comprises tungsten, as previously mentioned. The heat sink 201 is formed of copper-chromium-zirconium alloy material, with a heat transfer layer 301 between the armour layer 101 and the heat sink 201. The heat transfer layer 301 is labelled only in the enlarged view, for the sake of clarity. The heat transfer layer 301 comprises a low-oxygen copper layer that is bonded to the armour layer 101 , and to the heat sink 201 to provides a thermal bridge therebetween.

[0067] Also visible in the enlarged section, the impingement surface 211 is provided with a plurality of pin fins thereon, to aid in heat transfer from the impingement of gas jets on the impingement surface 211.

[0068] To aid manufacturing, the jet array element 220, impingement surface 211, heat transfer layer 301 and armour layer 101 may be manufactured separately and bonded to one another. Ideally, the impingement surface 211 is formed integrally with the pressure boundary of the heat sink 201.

[0069] FIG. 7 shows, schematically how an even distribution of jets is achieved, such a feature being desirable to level out temperature gradients across the impingement surface 221. The top view shows the jets, i.e. jet inlet openings of three aligned pluralities of jet inlet openings, arranged on the jet array element. The side view shows the location of so-called peaks of the jet array element, relatively close to the impingement surface, and therebetween troughs to carry away gas after it has been used to cool the impingement surface. As will be appreciated, the tops of the peaks lie closer to the impingement surface than the bottom of the troughs.

[0070] The jet inlet openings of a first plurality of jet inlet openings 211 are arranged in a linear array at constant spacing from one another. The jet inlet openings of the second plurality of jet inlet openings 222 are arranged in a corresponding linear array, in parallel alignment with the first plurality of jet inlet openings 211. The first plurality of jet inlet openings 221 is laterally offset from the second plurality of jet inlet openings 222. As shown, the jet inlet openings of the first plurality of jet inlet openings 221 are aligned midway between jet inlet openings of the second plurality of jet inlet openings 222. The jet inlet openings of the first and second pluralities of jet inlet openings 221, 222 divide the impingement surface 211 into a plurality of equilateral triangles, such as a plurality of identically sized equilateral triangles, with a jet inlet opening at each corner thereof.

[0071] In the example of FIG. 7, the jet array element 220 comprises a third plurality of jet inlet openings 223 for gas jet impingement cooling of the impingement surface 211. The relationship between first and third pluralities of jet inlet openings 221, 223 corresponds to that between the first and second pluralities of jet inlet openings 221, 222.

[0072] As will be appreciated from FIG. 7, in contrast with individual heat sink unit cells which build up into a composite plasma-facing component, such as finger, or pipe-in-pipe heat sink unit cells, the examples described herein enable sharing of baffle and structural rib components between elements within the heatsink. As well as eliminating the need for as many seals and structural supports, a reduction in material usage, and increased reliability are facilitated by the provision of shared internal gas deliver and exhaust systems, manifolds, and the like. Furthermore, the inboard-outboard dimension of the plasma-facing component can be kept low, even when implementing relatively large plate-type limiter components.

[0073] Various combinations of optional features have been described herein, and it will be appreciated that described features may be combined in any suitable combination. In particular, the features of any one example embodiment may be combined with features of any other embodiment, as appropriate, except where such combinations are mutually exclusive. Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of others.

[0074] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0075] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.

[0076] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent, or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0077] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. CLAIMS1. A plasma-facing component (1) comprising:an armour layer (101); anda heat sink (201) outboard of and in thermal contact with the armour layer (101); wherein:the heat sink (201) comprises:an impingement surface (211), anda jet array element (220) separated from the impingement surface (211) by a plenum space (231), the jet array element (220) comprising:(a) a first plurality of jet inlet openings (221) for gas jet impingement cooling of the impingement surface (211); and a second plurality of jet inlet openings (222) for gas jet impingement cooling of the impingement surface (211); and wherein the jet array element (220) further comprises a baffle (223) defining a shared outlet from the plenum space (231) for gas from the first and second pluralities of jet inlet openings (221); or(b) a first plurality of jet inlet openings (221) for gas jet impingement cooling of the impingement surface (211); and wherein the jet array element (220) further comprises a baffle (223) defining first and second outlets from the plenum space (231), the first and second outlets from the plenum space (231) shared by gas introduced to the plenum space (231) from the firstly plurality of jet inlet openings (221).

2. The plasma-facing component (1) of claim 1, wherein the jet array element (220) comprises both (a) and (b).

3. The plasma-facing component (1) of any preceding claim, wherein one, or both of the plenum space (231) and the shared outlet from the plenum space (231) extend along the length of the plasma-facing component.

4. The plasma-facing component (1) of any one of claims 1, 2 or 3, wherein the jet inlet openings (221, 222) are arranged in one or more a linear arrays, extending along the length of the plasma-facing component.

5. The plasma-facing component (1) of any preceding claim, comprising a first plurality of jet inlet openings (221) arranged in parallel alignment with a second plurality of jet inlet openings (221, 222), the first and second pluralities of jet inlet openings (221, 222) being laterally offset from one another.

6. The plasma-facing component (1) of any preceding claim, wherein the plenum space (231), and shared outlet therefrom, together with the baffle (223) comprise an internal manifolding arrangement for gas movement through the heat sink (201).

7. The plasma-facing component (1) of any preceding claim, wherein the plenum space (231) defines an unobstructed volume for the delivery of cooling gas from the jet inlet openings (221, 222) onto the impingement surface (211) and an unobstructed volume for the removal of cooling gas from the impingement surface (211) to the shared outlet.

8. The plasma-facing component (1) of any preceding claim, wherein jet inlet openings (221) of the first plurality of jet inlet openings (221) are aligned midway between jet inlet openings (222) of the second plurality of jet inlet openings (222), the jet inlet openings (222) of the second plurality of jet inlet openings (222) are aligned midway between jet inlet openings (221) of the first plurality of jet inlet openings (221), along the length of the plasma-facing component 1 .

9. The plasma-facing component (1) of any preceding claim, comprising a first, second and third plurality of jet inlet openings (221, 222, 223) for gas jet impingement cooling of the impingement surface (211); wherein the baffle (223) defines a sharedoutlet from the plenum space (231) for gas from the first and third pluralities of jet inlet openings (221, 223), as well as a shared outlet from the plenum space (231) for gas from the first and second pluralities of jet inlet openings (221, 222).

10. The plasma-facing component (1) of any preceding claim, wherein the jet inlet openings (221, 222) of the first and second pluralities of jet inlet openings (221, 222) divide the impingement surface (211) into a plurality of identically sized equilateral triangles, with a jet inlet opening (221, 222) at each corner thereof, and, if present the jet inlet openings (223) of the third plurality of jet inlet openings (223) divide the impingement surface (211) into a plurality of the equilateral triangles with those of the first plurality of jet inlet openings (221) on the same basis.

11. The plasma-facing component (1) of any preceding claim, wherein the jet array element (220) is supported by, and between, structural ribs (240).

12. The plasma-facing component (1) of claim 11, wherein the structural ribs (240) are integrally formed with the jet array element (220) and run the length of the plasmafacing component.

13. The plasma-facing component (1) of any preceding claim, wherein the baffle (223) and / or structural ribs (240) bound an inlet gas delivery volume for the jet array element (220), the inlet gas delivery volume defined between an inlet manifold for receiving cooling gas, and jet openings of the jet array element (220).

14. The plasma-facing component (1) of claim 13, wherein the cross section of the inlet gas delivery volume decreases with distance along the inlet gas delivery volume, such as with distance from the inlet manifold, by reduction in its inboard-outboard depth.

15. The plasma-facing component (1) of claim 13 or 14, wherein the baffle (223) and / or structural ribs (240) bound an outlet gas exhaust volume for the jet array element (220), the outlet gas exhaust volume defined between the plenum space (231) and an exhaust manifold for receiving used cooling gas.

16. The plasma-facing component (1) of claim 15, wherein the cross section of the outlet gas exhaust volume decreases with distance along the gas delivery volume, such as distance toward the exhaust manifold, by reduction in its inboard-outboard depth.

17. The plasma-facing component (1) of claim 15 or 16, wherein the baffle (223) separates the inlet gas delivery volume from the outlet gas exhaust volume such that the change in cross section in one is reflected by the change in cross section of the other, along their respective lengths.

18. The plasma-facing component (1) of any preceding claim, wherein in cross section the jet array element (220) comprises a plurality of jet inlet openings (221) inboard, with the baffle (223) extending in an outboard direction to define a side wall of the shared outlet, for example extending on one side of, or on both sides of the plurality of jet inlet openings (221) to define side walls of an outlet gas exhaust volume.

19. The plasma-facing component (1) of any preceding claim, wherein in cross section the jet array element (220) comprises a plurality of jet inlet openings (221) inboard, with the baffle (223) extending in an outboard direction to define a side wall of a shared inlet, for example extending in an outboard direction on one side of, or on both sides of the plurality of jet inlet openings (221) to define side walls of a gas delivery volume.

20. The plasma-facing component (1) of any preceding claim, wherein in cross section the jet array element (220) defines an alternating arrangement of inlet gasdelivery volume and outlet gas exhaust volume, by way of the side wall(s), or by way of the side wall(s) and one or more structural rib (240).

21. A plate-type plasma-facing component comprising a plurality of plasma-facing components as set out in any one of claims 1 to 20, formed integrally with each other.

22. The plate-type plasma-facing component of claim 21, comprising structural ribs (240) that divide units of the plasma-facing components from one another.

23. The plate-type plasma-facing component of claim 21 or 22, wherein, the structural ribs (240) divide the plate type plasma-facing component into a plurality of like units, with a shared inlet manifold (250) for cooling gas and a shared primary outlet (260), the shared primary input (250) running transverse to the structural ribs (240) and passing adjacent to the ends thereof and transverse thereto, and the shared outlet manifold (260) running transverse to the structural ribs (240), passing adjacent to the ends thereof and transverse thereto, with the inlet and outlet manifolds (250, 260) located at opposite ends of the structural rib (240).

25. A nuclear fusion power system, comprisinga vacuum vessel within which a plasma is produced,a plasma-facing components comprising the features of any preceding claim.

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