Stellarator coil for a nuclear fusion system, having support sub-plates that are curved in a maximum of one plane

Abstract

The invention relates to a 3D-shaped stellarator coil (1) for a nuclear fusion system, said stellarator coil being constructed from stacked plate layers (3), wherein each plate layer (2) has carrier sub-plates (7, 8, 11) which are connected in an annular manner. Grooves (12) in which a superconducting conductor (15) runs are arranged in the carrier sub-plates (7, 8, 11). For each carrier sub-plate (7, 8, 11), in the cross-section perpendicular to a local longitudinal direction (LLR) of the grooves (12), the following applies for an area SF occupied by support material of the carrier sub-plate (7, 8, 11) and an area LF occupied by the conductor (15) in the grooves (12): SF / (SF+LF)≥0.67. The plate layer stack (2) is held together by clamps (9) which are spaced apart from one another, and therefore the carrier sub-plates (7, 8, 11) and the clamps (9) together form a supporting structure (10) for absorbing the magnetic forces during operation. A respective plate layer (3) is constructed exclusively from carrier sub-plates (7, 8, 11) of the following three types: - type-1 carrier sub-plate (7), wherein grooves (12) run in a curved manner only in a common plate plane (17), - type-2 carrier sub-plate (8), wherein grooves (12) run in a curved manner only in mutually parallel transverse planes (18), - type-3 carrier sub-plate (11), wherein grooves (12) run in a straight manner. The stellarator coil according to the invention is simple and cost-effective to produce.

Description

[0001] SP14027PCT P 07.08.2025

[0002] Applicant:

[0003] Gauss Fusion GmbH

[0004] Parkring 29

[0005] 85748 Garching near Munich, Germany

[0006] Representative:

[0007] KOHLER. SCHMID FURNITURE

[0008] patent attorneys

[0009] limited liability partnership

[0010] Gropiusplatz 10

[0011] 70563 Stuttgart

[0012] Germany

[0013] Stellarator coil for a nuclear fusion plant, with support plates curved in a maximum of one plane

[0014] The invention relates to a stellarator coil for a nuclear fusion device, wherein the stellarator coil is designed as a non-planar, 3D-shaped, annular coil, and wherein the stellarator coil comprises a superconducting conductor wound with a plurality of turns, as well as a support structure suitable for mechanically stabilizing the stellarator coil under the influence of magnetic forces on the conductor during operation of the stellarator coil, wherein a plurality of annular plate layers are present, in each of which several of the turns of the conductor are wound, wherein in each plate layer a plurality of sub-plates are arranged annularly one after the other and successive sub-plates in the respective plate layer are attached to one another, and wherein the plate layers form a plate layer stack and successive plate layers abut one another.

[0015] Gauss Fusion GmbH 07.08.2025 SP14027PCT wherein each subplate forms several grooves into which the conductor is inserted, wherein the grooves of the subplate run along a local longitudinal direction, and the grooves of the subplate are arranged successively in a local transverse direction, wherein a local stacking direction is perpendicular to the local longitudinal direction and perpendicular to the local transverse direction, and wherein the grooves of successive subplates of a plate layer connect to one another.

[0016] Such a stellarator coil was described by F. Schauer et al., “Extrapolation of the W7-X Magnet System to Reactor Size”, Contrib. Plasma Phys. 50, No. 8, 750-755 (2010).

[0017] Nuclear fusion is a promising technology for generating electricity. It involves fusing two light reactants, or rather their atomic nuclei, typically deuterium and tritium, releasing energy. The reaction takes place in a plasma. Currently, major efforts are underway worldwide to practically implement a fusion power plant. The most widely pursued development approach involves confining the plasma using appropriately shaped magnetic fields.

[0018] Typically, fusion reactors with a substantially toroidal plasma volume geometry are used; the tokamak and stellarator designs are well-known examples. In both cases, a multitude of magnetic coils are arranged along the substantially toroidal plasma volume, each locally enclosing the toroidal plasma volume in a ring-like fashion. The magnetic coils are superconducting.

[0019] In the tokamak design, which is used, for example, in the ITER fusion reactor, the individual magnetic coils (or tokamak coils) each have a flat, so to speak, two-dimensional geometry. A tokamak requires an electric current flowing in the plasma. In the stellarator design, the individual

[0020] Gauss Fusion GmbH 07.08.2025 SP14027PCT Magnetic coils (or stellarator coils) each have a non-planar, 3D shaped geometry; the construction is therefore somewhat more complex. No current flowing in the plasma is required in the stellarator.

[0021] One technical challenge lies in the design of the individual magnetic coils, which are arranged along the plasma volume. These magnetic coils must, on the one hand, provide sufficiently strong magnetic fields for confining the plasma, and on the other hand, they must be stable enough to withstand the magnetic forces acting upon them.

[0022] The tokamak coils at ITER (as described, for example, by F. Schauer et al. in Contrib. Plasma Phys., ibid.) incorporate a total of seven double-pankake conductor assemblies, with the two outer conductor assemblies being angled. Each of these double-pankake conductor assemblies comprises a flat radial plate made of steel, and the conductor runs in grooves formed on both sides of the radial plate. The radial plates are stacked on top of each other. The stacked radial plates are enclosed on all sides by a coil housing that holds the stacked radial plates together. Due to the flat design, the fabrication and stacking of the radial plates is straightforward; however, the coil housing is complex and expensive.

[0023] F. Schauer et al. in Contrib. Plasma Phys., ibid., discussed the construction of stellarator coils based on the design of the ITER tokamak coils, particularly for the HSR50a reactor, which belongs to the HELIAS type. They noted that, among other things, the coil housing, radial plates, and conductors would need to be bent for the stellarator coil. Furthermore, the radial plates could be manufactured in segments and then welded together.

[0024] Based on F. Schauer et al., “Coil winding pack FE-analysis for HELIAS reactor”, Fusion Engineering and Design 86 (2011), 636-639, coil winding packs for the HELIAS reactor HSR50a are investigated, with square coil cable sheaths being proposed. Non-planar stellarator coils or their winding packs, as well as the loads acting during operation, are illustrated.

[0025] Gauss Fusion GmbH 07.08.2025 SP14027PCT From H. Nakajima et al., “Development of optimum manufacturing technologies of radial plates for the ITER, toroidal field coils”, Fusion Engineering and Design, Vol. 82, 2007, pp. 1473-1480, it became known to construct coils for the ITER toroidal field using flat radial plates in which grooves for a superconductor run. In the radial plates, the grooves run on the top and bottom surfaces in a common plane, either straight or curved within that plane.

[0026] In V. Queral et al., “Evaluation of metal additive manufacturing for high-field modular-stellarator radial plates and conductors”, Nuclear Materials and Energy, Vol. 30, 2022, 101149 (9 pp.) it has been proposed to use additively manufactured radial plates for high-field modular stellarator coils.

[0027] The purpose of the invention is to present a stellarator coil that is simple and inexpensive to manufacture.

[0028] This problem is solved according to the invention by a stellarator coil of the type mentioned above, characterized in that the sub-plates are designed as support sub-plates, wherein, for a respective support sub-plate in cross-section perpendicular to the local longitudinal direction, the following applies to an area SF occupied by support material of the support sub-plate and an area LF occupied by the conductor in the grooves: SF / (SF+LF)>0.67; that the support structure is formed by

[0029] - the support plates of the plate layers as well as through

[0030] Gauss Fusion GmbH 07.08.2025 SP14027PCT - several clamps distributed and spaced apart along a circumference of the stellarator coil, with which the plate layers are clamped, and that each plate layer is exclusively composed of carrier plates of the following three types:

[0031] - Type 1 support plate, wherein in each type 1 support plate the grooves are curved only in a common plate plane, this common plate plane containing the local longitudinal direction and the local transverse direction, and the grooves are curved with respect to a common center point,

[0032] - Type 2 support plate, wherein in each type 2 support plate the grooves run curved only in mutually parallel transverse planes, these parallel transverse planes containing the local longitudinal direction and perpendicular to the local transverse direction, and whose grooves have a common radius of curvature,

[0033] - Type 3 support plate, wherein the grooves of each Type 3 support plate are straight, and wherein each plate layer has at least several Type 1 support plates and several Type 2 support plates.

[0034] The stellarator coil according to the invention can be easily constructed with a stack of plate layers, even though the stellarator coil is 3D-shaped and non-planar. The good stackability is achieved by simply installing support plates of types 1, 2, and 3 described above in each plate layer. The easily stackable plate layers can be held together simply by means of clamps. The support plates have a cross-sectional area with a particularly high area of ​​support material compared to the area of ​​the conductor, so that sufficient mechanical strength during operation (and under the prevailing magnetic forces) can be achieved by the support plates together with the clamps alone. In particular, no complex and

[0035] Gauss Fusion GmbH 07.08.2025 SP14027PCT A more expensive coil housing is no longer needed. This will be explained in more detail below.

[0036] A stellarator coil according to the invention comprises a plurality of type 1 support plates, in particular different type 1 support plates (with different curvatures of the grooves in the same (transverse) position and / or different plate lengths in the longitudinal direction), and a plurality of type 2 support plates, in particular different type 2 support plates (with different curvatures of the grooves and / or different plate lengths in the longitudinal direction), and usually also a plurality of type 3 support plates, in particular different type 3 support plates (with different plate lengths in the longitudinal direction). The curvatures of the grooves in the type 1 and type 2 support plates are each circular arcs.

[0037] The course of a groove can be represented by the course of a central axis of the groove (or a central axis of the associated conductor inserted into the groove), in particular for determining the curvature of the groove along its course.

[0038] Other types of support plates besides types 1, 2 and 3 are not used, in particular no support plates where the grooves have a curvature in several planes (and thus a torsion).

[0039] This allows the support plates or entire plate layers to be easily positioned or stacked next to each other and clamped together simply and securely. Virtually any 3D-shaped stellarator coil can be assembled using the three types of support plates. A simple, compact, and stable stellarator coil assembly based on the plate layers and clamps is possible.

[0040] The support plates have (compared to prior art plates) a high proportion of supporting material (e.g., steel) in the cross-section, compared to the

[0041] Gauss Fusion GmbH 07.08.2025 SP14027PCT Conductor ratio (relative to cross-sectional area). This allows the support plates to ensure high mechanical stability. The support plates, together with the clamps, can then be self-supporting and thus form the support structure of the stellarator coil, which absorbs the magnetic forces during operation and essentially prevents deformation of the conductor or the stellarator coil. Accordingly, the stellarator coil no longer requires an additional housing to maintain its shape during operation under the influence of strong magnetic forces.

[0042] The plate layers, or the associated support plates, are stacked on top of each other, with adjacent support plates generally aligning their contact surfaces along their local stacking direction. The local longitudinal direction, the local transverse direction, and the local stacking direction are perpendicular to each other. Each Type 1 support plate has a uniform (local) stacking direction. Each Type 2 support plate has a uniform (local) transverse direction. Each Type 3 support plate has a uniform (local) longitudinal direction and a uniform (local) transverse direction, and therefore also a uniform (local) stacking direction.

[0043] With respect to the individual stellarator coil as a whole, the local longitudinal directions of the grooves of the support plates of a plate layer run roughly in the circumferential direction of the stellarator coil, furthermore the local transverse directions roughly in the radial direction of the stellarator coil, and the local stacking directions roughly along an axis ("local cylinder axis") of the stellarator coil.

[0044] Typically, all local stacking directions occurring in the stellarator coil have a directional component along the axis ("local cylinder axis") of the (individual) stellarator coil. This axis essentially corresponds to the toroidal direction of a stellarator in which the stellarator coil is installed. The toroidal direction passes through the opening of the stellarator coil; in the finished stellarator, the plasma volume extends along the toroidal direction. Accordingly, the plate layers can be manufactured in this way.

[0045] Gauss Fusion GmbH 07.08.2025 SP14027PCT in the direction of the axis (cylinder axis) or the toroidal direction are driven towards each other.

[0046] The cross-sectional profile (perpendicular to the local longitudinal direction) of the grooves in a given support plate remains constant along the plate's length (notwithstanding any changes in the winding of the grooves and / or any plate layer changes of the conductor). Typically, the cross-sectional profile (perpendicular to the local longitudinal direction) of a given support plate remains constant along the entire plate's length (notwithstanding any changes in the winding of the grooves and / or any plate layer changes and / or joints). A support plate typically has an at least approximately rectangular cross-section perpendicular to the local longitudinal direction. A given support plate typically has a uniform plate thickness PD (along the local stacking direction), a uniform plate width PB (along the local transverse direction), and a plate length PL (along the local longitudinal direction; possibly...).as determined as mean plate length), where PD <PB und PD<PL, typischerweise PD<0,2*PB und PD<0,2*PL, und meist auch PB<PL. Alternativ kann das Querschnittsprofil über die Plattenlänge auch veränderlich sein (zB die Plattendicke und / oder die Plattenbreite sind veränderlich), insbesondere für eine Anpassung an lokal variierende magnetische Kräfte.

[0047] Each support plate typically has two so-called stacking surfaces, which are formed at least substantially perpendicular to the local stacking direction. Support plates in adjacent plate layers within the plate stack then abut each other with these stacking surfaces. For support plates in an edge plate layer, one such stacking surface is sufficient (although two such stacking surfaces may be present, only one of which is then used during stacking), and support plates in a non-edge ("middle") plate layer have two such stacking surfaces (both of which are used during stacking). If a support plate has two stacking surfaces, these are opposite each other with respect to the local stacking direction and are (at least substantially) parallel to each other.

[0048] Gauss Fusion GmbH 07.08.2025 SP14027PCT The grooves are designed to accommodate the conductor; typically, the cross-section of the groove (perpendicular to the local longitudinal direction) corresponds at least partially to the outer cross-section of the conductor. A groove can be U-shaped (especially for a round conductor). Alternatively, a groove can also be rectangular (especially for a rectangular conductor).

[0049] The superconducting conductor is typically a compound conductor comprising a plurality of superconducting wires (e.g., 100 or more bundled wires) or a plurality of superconducting tapes (e.g., 100 or more bundled and / or stacked tapes), designed for a total operating current of 10 kA or more. The conductor may, in particular, be configured as a CICC (cable-in-conduit conductor). The conductor may, in particular, have a circular cross-section; alternatively, the conductor may have a rectangular or square cross-section. The conductor may contain LTS material. Alternatively, the conductor may contain HTS material (typically supplied with superconducting tapes). Typically, the conductor forms 100 or more turns in the stellarator coil.The conductor can be wound in a spiral pattern, particularly within a given layer of plates. The radius change of each turn can be distributed over the entire circumference (spiral winding in the narrower sense) or limited to a transition zone forming part of the circumference, typically in which case the transition zone is formed in only one support plate, which can be of type 1, 2, or 3. The windings within a plate layer are typically connected in series. Furthermore, the windings of the plate layers are typically connected in series with each other. Typically, a transition is provided for the two outermost (i.e., radially inner and radially outer) slots of each plate layer to the adjacent plate layers in the stack (or to an adjacent plate layer and "outside" the coil in the case of an edge plate layer).A joint is typically established at such a transition.

[0050] Gauss Fusion GmbH 07.08.2025 SP14027PCT The clamping with the clamps is preferably releasable. The plate layers in the plate layer stack are typically not glued together.

[0051] Preferred embodiments of the invention

[0052] A preferred embodiment of a stellarator coil according to the invention provides that each support plate has one or two stacking surfaces which are formed at least substantially perpendicular to the local stacking direction, that in each type 1 support plate one or two stacking surfaces are formed flat and parallel to the common plate plane of the type 1 support plate, that in each type 2 support plate a) one or two stacking surfaces are formed curved about a type 2 main axis, on which the centers are also located with respect to which the grooves of the type 2 support plate are curved, wherein the type 2 main axis is parallel to the local transverse direction, and b) one or two stacking surfaces are formed parallel to the local transverse direction.and that in each type 3 support plate, one or two stacking surfaces are flat and parallel to a common plate plane of the type 3 support plate, the common plate plane encompassing the local longitudinal and transverse directions. This design is easy to manufacture and allows for a particularly efficient transmission of the clamping force along the (local) stacking direction into the support plates.

[0053] A preferred embodiment is one in which the stack of plate layers forms sub-stacks, wherein in each sub-stack only support plates of one of the three types are stacked, wherein in each sub-stack of type 1 support plates a) the associated plate planes are all parallel to each other and b) the associated center-

[0054] Gauss Fusion GmbH 07.08.2025 SP14027PCT The points of the grooves with respect to which the grooves of the support plates of this sub-stack are curved all lie on a common Type 1 principal axis that runs perpendicular to the plate planes, wherein in a respective sub-stack of Type 2 support plates the associated centers of the grooves with respect to which the grooves of the support plates of this sub-stack are curved all lie on a common Type 2 principal axis that runs parallel to the local transverse direction, and wherein in a respective sub-stack of Type 3 support plates the associated common plate planes are all parallel to each other, wherein a respective common plate plane of a Type 3 support plate contains the local longitudinal direction and the local transverse direction. This also leads to a particularly simple construction and efficient force transmission.The support plates of each sub-stack of type 1 support plates also have a uniform plate length PL. Likewise, the support plates of each sub-stack of type 3 support plates have a uniform plate length PL.

[0055] An advantageous embodiment involves welding together at least a subset of the successive support plates in a given plate layer. Fastening the support plates by welding is mechanically very robust and durable. Advantageously, the welding is performed while webs still remain at the ends of the grooves, so that uncontoured, generally rectangular end faces are welded together (see also below).

[0056] A particularly advantageous embodiment is one in which one or more covers are arranged and fixed to each of the support plates, with which the inserted conductor is covered and fixed in the grooves, especially wherein the cover or covers are welded to the support plate. The covers protect the conductors and contribute to the mechanical stabilization of the stellarator coil. When covers are used, their cross-sectional area is perpendicular to the local longitudinal direction.

[0057] Gauss Fusion GmbH 07.08.2025 SP14027PCT The area of ​​the support material (SF, see above) is added. Typically, the covers form a flush finish in the area of ​​the grooves with respect to the rest of the support plate.

[0058] A further advantage is an embodiment in which the conductor inserted into the grooves is provided with electrical insulation, in particular in which the conductor is wrapped with one or more insulating strips. In the event of a quench, this prevents a short circuit between adjacent turns of the conductor via the material of the support plates. An insulating strip can, for example, be designed as a Kapton strip or as an insulating glass strip.

[0059] A preferred embodiment is one in which the plate layers are electrically insulated from one another, particularly in which the support plates of a respective plate layer are wrapped with one or more electrically insulating tapes. In the event of a quench, this prevents a short circuit between the conductor sections of successive plate layers via the material of the support plates. An insulating tape can, for example, be designed as a Kapton tape or as an insulating glass tape.

[0060] A preferred embodiment is one in which the cross-sectional profile of the grooves remains constant along the length of each support plate, perpendicular to the local longitudinal direction, regardless of any changes in the groove winding and / or plate layer. This allows the conductor to be held stably in the grooves at all times, and mechanical stresses on the conductor are minimized.

[0061] Advantageously, in one embodiment, a change in winding is provided in each plate layer on one of the support plates. This allows for a change in winding in only one support plate.

[0062] Gauss Fusion GmbH 07.08.2025 SP14027PCT is set up, the structure of the remaining carrier plates of the plate layer is kept simple.

[0063] A preferred embodiment is one in which a number of AN grooves are arranged successively in the transverse direction in each support plate, with 5 <AN<20, bevorzugt 6<AN<15, besonders bevorzugt 8<AN<12. Diese Anzahl AN von Nuten hat sich in der Praxis besonders bewährt. Es kann dann mit moderatem Herstellungsaufwand eine ordentliche supraleitende Querschnittsfläche eingerichtet werden. Insbesondere kann AN = 10 gewählt werden.

[0064] Also preferred is an embodiment in which a number of APS of plate layers form the plate layer stack, with 5 <APS<20, bevorzugt 6<APS<15, besonders bevorzugt 8<APS<12. Diese Anzahl APS von Plattenschichten hat sich in der Praxis ebenfalls besonders bewährt. Es kann dann mit moderatem Herstellungsaufwand eine ordentliche supraleitende Querschnittsfläche eingerichtet werden. Insbesondere kann APS = 10 gewählt werden.

[0065] A preferred embodiment is one in which SF / (SF+LF) > 0.75, preferably SF / (SF+LF) > 0.80. The high quotient Q = SF / (SF+LF) allows for particularly good mechanical stability of the stellarator coil, suitable even for high magnetic field strengths. Note, however, that the quotient should not be too large (e.g., Q < 0.95 or Q < 0.90) in order to provide a sufficient cross-sectional area for carrying the superconducting current.

[0066] In a preferred embodiment, it is provided that in each support plate exactly one series of grooves, arranged successively in the transverse direction, is formed.

[0067] Gauss Fusion GmbH 07.08.2025 SP14027PCT and that the grooves of this exact row are open to the same side of the support plate, irrespective of any cover closing a respective groove. This allows a continuous, closed and undamaged surface of support material in cross-section to be established behind the grooves, on the side of the support plate facing away from the grooves, so that particularly good mechanical stability can be achieved.

[0068] A particularly preferred embodiment is one in which, for a respective support plate in cross-section perpendicular to the local longitudinal direction, the following applies to a partial thickness NTD of the support plate on the slot side between the conductors of exactly one row and a first outer surface, in particular a stacking surface, of the support plate on the side towards which the slots are open, and to a partial thickness ATD of the support plate on the side opposite the slot between the conductors of exactly one row and an outer surface, in particular a stacking surface, of the support plate on the side towards which the slots are not open: ATD > NTD, preferably ATD > 1.5 * NTD, particularly preferably ATD > 2 * NTD. The large partial thickness ATD on the side opposite the slot (compared to the partial thickness NTD on the slot side) further improves the mechanical stability of the support plate.

[0069] Also particularly preferred is a further development of the above embodiment in which, for a respective carrier plate in cross-section perpendicular to the local longitudinal direction, the following applies for a partial thickness ATD of the carrier plate facing away from the grooves between the conductors of exactly one row and an outer surface, in particular a stacking surface, of the carrier plate on the side to which the grooves are not open, and a maximum diameter GDL of the conductors along the local stacking direction: ATD>0.5*GDL, preferably ATD>1*GDL,

[0070] Gauss Fusion GmbH 07.08.2025 SP14027PCT particularly prefers ATD>1.25*GDL. The large thickness ATD on the side facing away from the groove (compared to the largest diameter GDL of the conductor) further improves the mechanical stability of the support plate.

[0071] An advantageous embodiment also provides that the support plates of each plate layer have a uniform plate thickness PD in the local stacking direction, preferably wherein the support plates of all plate layers have a uniform plate density PD in the local stacking direction, and preferably wherein the support plates of all plate layers have a uniform plate width PB in the local transverse direction. This makes the construction of the stellarator coil particularly simple and cost-effective, and stacking and clamping are also particularly easy.

[0072] An advantageous embodiment provides that the clamps have an average circumferential spacing DAA from each other, and the support plates of the stellarator coil have an average plate width DPB along the local transverse direction, with DAA > 3*DPB, preferably DAA > 5*DPB. These spacings have proven effective in practice. Appropriately spaced clamps enable the cost-effective creation of a mechanically stable plate stack. The spacing DAA is measured along the circumference of the stellarator coil, at the center of the plate stack (where relevant). In some cases, DAA > 1.5*DPB can also be used. Note, however, that DAA should not be chosen too large, for example, with DAA < 12*DPB.

[0073] A preferred embodiment comprises: - two clamping plates which, at a circumferential position of the stellarator coil, bear against a bottom plate layer and a top plate layer of the plate layer stack from the outside,

[0074] Gauss Fusion GmbH 07.08.2025 SP14027PCT - a number M of tie rods, with M>2, preferably M>4, wherein each tie rod has one or two threaded end sections, hereinafter referred to as threaded end sections, wherein each threaded end section projects through a recess in one of the clamping plates, and the threaded end section is clamped against the clamping plate with a nut, the nut engaging behind the clamping plate. This clamping arrangement is cost-effective and easy to assemble and disassemble, if necessary. Preferably, each clamping plate has a length (along the local longitudinal direction) KPL and a width KPB (along the transverse direction), with 0.05*DPB <KPL<0,5*DPB oder in anderen Fällen 0,5*DPB<KPL<l*DPB oder auch 0,75*DPB<KPL<l,5*DPB, und / oder 1*DPB<KPB<1,5*DPB.A typical end section of the unthreaded pull rod has a projection that engages the clamping plate, and this end section extends through a recess in the clamping plate. The projection secures the end section against the clamping plate; this is achieved using the nut on the opposite threaded end section of the pull rod. The recesses are typically designed as holes; alternatively, they can be designed, for example, as recesses open towards an edge of the clamping plate. During assembly of the stellarator coil, the stack of plates, including the two clamping plates, is compressed using a pre-tensioning device (also called a temporary clamping mechanism) to install a clamp. While compressed, the nuts on the threaded end sections are tightened. The pre-tensioning device can then be removed, leaving the clamping plates clamped.

[0075] Stellarator according to the invention

[0076] The present invention also includes a stellarator for a nuclear fusion device, suitable for the magnetic confinement of a substantially toroidal plasma volume, wherein the stellarator comprises a plurality of stellarator coils according to the invention as described above.

[0077] Gauss Fusion GmbH 07.08.2025 SP14027PCT wherein the stellarator coils are arranged distributed in the toroidal direction of the plasma volume, and wherein each stellarator coil locally encloses the toroidal plasma volume in a ring-like fashion. A corresponding stellarator can confine a plasma without requiring an electric current within the plasma. The stellarator coils are simple and inexpensive to manufacture. The stellarator coils are poloidally closed. The plasma volume passes through their respective ring openings.

[0078] A preferred embodiment of the stellarator according to the invention provides that, for each stellarator coil, all local stacking directions are aligned with a directional component along the local toroidal direction. The local toroidal direction essentially corresponds to a (cylindrical) axis of a single stellarator coil at that location. Typically, the local stacking directions deviate from the local toroidal direction by 60° or less, usually 45° or less. Stacking (aligning) the plate layers is then particularly simple.

[0079] An advantageous embodiment includes a cryostat in which the stellarator comprises a cryostat, with each stellarator coil arranged within the cryostat without a housing. This design is particularly simple and cost-effective, and especially space-saving and material-efficient. Due to the support structure provided by the carrier plates of the plate layers and the clamps, the stellarator coils do not require additional support from a housing.

[0080] Inventive method for manufacturing a stellarator coil

[0081] Also within the scope of the present invention is a method for manufacturing a stellarator coil according to the invention, described above, comprising the following steps:

[0082] Gauss Fusion GmbH 07.08.2025 SP14027PCT Step a) the support plates required for the stellarator coil are manufactured, including at least several type 1 support plates and several type 2 support plates, with webs remaining at the ends of the grooves on at least a subset of the support plates;

[0083] Step b) the support plates of each plate layer are arranged successively in a ring shape, and at least in a subset of the support plates, butt joints are welded together, with webs remaining at the ends of the grooves on these welded joints;

[0084] Step c) The remaining webs are removed, in particular by milling; Step d) The conductor is inserted into the grooves;

[0085] Step e) The plate layers are placed next to each other and clamped together. The clamping in step e) is preferably releasable. Because the welding in step b) is still carried out with the webs, a particularly robust weld seam can be reliably obtained at the joints of the support plate sections. After the webs are subsequently removed, the conductor can be inserted.

[0086] An advantageous variant of the inventive method is one in which, in step d), covers are further arranged on the support plates with which the inserted conductor is fixed in the grooves, in particular wherein the covers are welded to the support plates. This protects the conductors, and the cross-section of the covers also contributes to the mechanical stabilization of the stellarator coil. The covers can also improve the support of a subsequent support plate placed on top.

[0087] A preferred method variant involves first fabricating the conductor and, after its fabrication, bending it into a shape corresponding to the required shape in the stellarator coil, either before or during step d). This approach is particularly simple and can be readily applied to deformable conductors (e.g., those based on NbTi or some types of deformable, HTS-based conductors).

[0088] Gauss Fusion GmbH 07.08.2025 SP14027PCT In an alternative, advantageous method variant, it is provided that the conductor is produced directly in a mold corresponding to the required shape in the stellarator coil before step d). This allows conductors that are not deformable or only slightly deformable (e.g., based on Nb3Sn or shapes of HTS-based conductors that are pre-formed / prefabricated to fit the carrier plates and the slots) to be installed in a stellarator coil according to the invention. The production of the conductor in a mold corresponding to the required shape can, in particular, include a reaction heat treatment of a semi-finished product containing Sn and Nb, whereby NbsSn is formed during the reaction heat treatment.

[0089] Further advantages of the invention will become apparent from the description and the drawing. Likewise, the features mentioned above and those described in more detail below can each be used individually or in any combination according to the invention. The embodiments shown and described are not to be understood as an exhaustive list, but rather serve as examples for illustrating the invention.

[0090] Detailed description of the invention and drawing

[0091] Fig. 1 shows a schematic side view of an embodiment of an inventive stellarator coil based on a stack of plate layers;

[0092] Fig. 2 shows various schematic views of an exemplary plate layer for a stellarator coil according to the invention;

[0093] Fig. 3 shows a schematic perspective view of part of an exemplary plate layer in the area of ​​three support plates, for the invention;

[0094] Fig. 4 shows a schematic top view of the part of the plate layer of Fig. 3;

[0095] Gauss Fusion GmbH 07.08.2025 SP14027PCT Fig. 5 shows a schematic side view of part of the plate layer of Fig. 3;

[0096] Fig. 6 shows in partial images TB1, TB2, TB3 a schematic top view, a front view and a side view of an exemplary carrier plate of type 1, for the invention, and in partial image TB4 an exemplary partial stack of corresponding carrier plates;

[0097] Fig. 7 shows in partial images TB1, TB2, TB3 a schematic top view, a front view and a side view of an exemplary carrier plate of type 2, for the invention, and in partial image TB4 an exemplary partial stack of corresponding carrier plates;

[0098] Fig. 8 shows a schematic cross-sectional view along the local longitudinal direction through an exemplary carrier plate of type 3, for the invention;

[0099] Fig. 9 shows a schematic cross-section along the local longitudinal direction through an exemplary partial stack in the area of ​​a clamp, for the invention;

[0100] Fig. 10 shows a schematic top view of the partial stack of Fig. 9;

[0101] Fig. 11 schematically illustrates the production of a plate layer within the scope of the invention using an exemplary part of the plate layer in the area of ​​three support plates, with separate support plates and webs;

[0102] Fig. 12 illustrates the part of the plate layer of Fig. 11, with the carrier part plates joined and welded together;

[0103] Fig. 13 illustrates the part of the plate layer of Fig. 12 after the removal of the webs;

[0104] Gauss Fusion GmbH 07.08.2025 SP14027PCT Fig. 14 illustrates the joining of several plate layers to form a plate layer stack, for the invention;

[0105] Fig. 15 shows in a schematic, partially cutaway top view an exemplary embodiment of a stellarator according to the invention;

[0106] Fig. 16 shows a schematic cross-section through the stellarator of Fig. 16;

[0107] Fig. 17 shows a schematic top view of an exemplary carrier plate with a change of winding, for the invention;

[0108] Fig. 18 shows another embodiment of a stellarator coil according to the invention, wherein the terminals are designed with a larger terminal plate length and four pull rods each.

[0109] Fig. 1 schematically shows an exemplary embodiment of a stellarator coil 1 according to the invention for a nuclear fusion device in a side view, with the viewing direction oriented along a (cylinder-like) axis 50 perpendicular to the plane of the drawing in Fig. 1 of the stellarator coil 1. Note that the axis 50 corresponds approximately to the local toroidal direction of the substantially toroidal plasma volume in a complete stellarator (see Fig. 15).

[0110] The stellarator coil 1 comprises a stack of plate layers 2 and a plurality of terminals 9. The stack of plate layers 2 comprises several stacked plate layers 3, in the example shown six plate layers 3 (three plate layers 3 are marked with reference lines by way of example). Each plate layer 3 comprises a plurality of support plates 7, 8, which are attached to one another in a ring-like arrangement and in which a superconducting conductor runs (for the individual plate layer 3 see Fig. 2, for the conductor see Fig. 3 and Fig. 8).

[0111] Gauss Fusion GmbH 07.08.2025 SP14027PCT For simplification, the boundary between adjacent plate layers 3 is marked with dotted lines in Fig. 1 only in the area of ​​two sub-stacks 4, 5 of support plates 7, 8. Sub-stack 4 is formed here by support plates 7 of type 1 (with groove curvature in the plate plane), and sub-stack 5 is formed here by support plates 8 of type 2 (with groove curvature in parallel transverse planes), and another sub-stack 6 is formed here by support plates of type 3 (with straight grooves, support plates not specifically marked here). The grooves are not shown in detail in Fig. 1, but see, for example, Fig. 2 and Fig. 3.

[0112] The stack of plate layers 2, and consequently also the individual plate layers 3 and the stellarator coil 1 as a whole, are formed in a closed ring shape. The superconducting conductor (not shown in detail) runs in a multitude of turns within the plate layers 3, more precisely in grooves of the support plates 7, 8 (see, for example, Fig. 3 for the conductor). An electric current flowing through the conductor generates a portion of a magnetic field that can be used to confine the plasma volume.

[0113] The clamps 9 hold the stack of plate layers 2 together; each clamp 9 clamps the stack of plate layers 2 along a local stacking direction LSR. Together with the support plates 7, 8, the clamps 9 form a support structure 10 for the stellarator coil 1, which, during operation, can absorb the magnetic forces on the stellarator coil 1 and prevent or at least minimize deformations of the stellarator coil 1. Adjacent clamps 9 have an individual distance AA along the circumferential direction of the stellarator coil 1 (for the selected design and the specific pair of clamps); the distance AA can be determined, in particular, along a central axis of the stack of plate layers 2. The average distance of adjacent clamps 9 along the circumferential direction in the stellarator coil 1 is denoted by DAA.The support plates 7, 8 have a uniform plate width PB in the illustrated embodiment, which here also corresponds to the average plate width DPB. In the illustrated design, DAA = 3*DPB.

[0114] Gauss Fusion GmbH 07.08.2025 SP14027PCT Note that all local stacking directions LSR in the stellarator coil 1 have a directional component along axis 50. This facilitates the formation of the plate layer stack 2 from the plate layers 3.

[0115] Fig. 2 shows an exemplary single plate layer 3 for a stellarator coil according to the invention, in three different perspective views; see the partial images TB1, TB2, TB3. The plate layer 3 consists of a plurality of ring-shaped support plates 7, 8, 11 arranged successively and attached to one another. In the support plates 3, a plurality of grooves 12 for the conductor (conductor not shown in detail) run along one of the opposite flat sides; two of the grooves 12 are shown by way of example in Fig. 2.

[0116] The grooves 12 extend along the entire circumference of the plate layer 3 and locally along a local longitudinal direction LLR. The support plates 7, 8, 11 have a uniform plate width PB along a local transverse direction LQR; in the local transverse direction LQ, the grooves 12 are arranged in the respective support plates 7, 8, 11. Furthermore, the support plates 7, 8, 11 have a uniform plate thickness PD along the local stacking direction LSR. The local stacking direction LSR is perpendicular (at every point in the plate layer 3) to both the local longitudinal direction LLR and the local transverse direction LQR. The lengths PL of the support plates 3 along the local longitudinal direction LLR are individually different.

[0117] Each carrier plate 7, 8, 11 belongs to one of three types:

[0118] - Type 1 (see support plate 7), each with curvature of the grooves 12 in a plate plane that contains the local longitudinal direction LLR and the local transverse direction LQR (plate planes not shown in Fig. 2, but see Fig. 4 and Fig. 5 for details);

[0119] - Type 2 (support plates 8), each with curvature of the grooves 12 in transverse planes parallel to each other; the transverse planes run perpendicular to the local transverse direction LQR (transverse planes not shown in Fig. 2, but see Fig. 7);

[0120] Gauss Fusion GmbH 07.08.2025 SP14027PCT Type 3 (support plates 11), each with non-curved grooves 12, and corresponding non-curved support plates 11.

[0121] Fig. 3 shows a portion of an exemplary plate layer 3, in which a support plate 11 of type 3, a support plate 7 of type 1, and a support plate 8 of type 2 are arranged one after the other. The support plates 7, 8, and 11 form ten grooves 12 on a first side 13 (side 13 facing the grooves), and there are no grooves on the opposite side 14 (side 14 facing away from the grooves). The conductor 15 is inserted into each of the grooves 12; for the upper right groove 12, the conductor 15 and a cover 16 are shown separately for clarity. The grooves 12 are aligned at the transitions between the support plates 7, 8, and 11.

[0122] As can be clearly seen in Fig. 3, in the support plate 11 of type 3, the local longitudinal direction LLR, the local transverse direction LQR, and the local stacking direction LSR are uniform. In the support plate 7 of type 1, the local longitudinal direction LLR and the local transverse direction LQR are variable, and the local stacking direction LSR is uniform. In the support plate 8 of type 2, the local longitudinal direction LLR and the local stacking direction LSR are variable, and the local transverse direction LQR is uniform.

[0123] Figure 4, a top view (without the covers), and Figure 5, a side view, again show the portion of the plate layer 3 from Figure 3. It is clearly evident that in the support plate 7 of type 1, the grooves 12 are curved in a common plate plane 17; this common plate plane 17 contains the local longitudinal direction LLR and the local transverse direction LQR, and thus the plate plane 17 is perpendicular to the local stacking direction LSR. Similarly, in the support plate 8 of type 2, the mutually parallel transverse planes 18, in which the grooves 12 are curved, are visible; the transverse planes 18 each run perpendicular to the local transverse direction LQR and contain the local longitudinal direction LLR. Furthermore, the support plate 11 can also be shown to have a curved groove 12.

[0124] Gauss Fusion GmbH 07.08.2025 SP14027PCT A common plate plane 49 is assigned, in which its grooves 12 run in a straight direction. This common plate plane 49 contains the local longitudinal direction LLR and the local transverse direction LQR.

[0125] The grooves 12 in the support plate 7 of type 1 are therefore curved only in one plane, namely the plate plane 17. The grooves 12 of the support plate 8 of type 2 are likewise curved only in one plane, namely the respective transverse plane 18. The grooves of the support plate 11 of type 3 are not curved at all and run straight along the local longitudinal direction LLR. The grooves of each support plate 7, 8, 11 are therefore curved in at most one plane.

[0126] Figure 6 shows, in a highly schematic manner, in sub-images TB1, TB2, and TB3, another support plate 7 of type 1 in a top view (TB1, see corresponding view BR1), a front view (TB2, see corresponding view BR2), and a side view (TB3, see corresponding view BR3), here with five grooves 12 (i.e., with a number of grooves AN=5). In the top view of sub-image TB1, it is clearly visible that all grooves 12 are curved with respect to a common center point 19.

[0127] Partial image TB4 of Fig. 6 (in side view, analogous to TB3) shows a partial stack 4, formed here by five support plates 7 (i.e., with a corresponding number of plate layers APS = 5). The support plates 7 are all identical and each has two opposing stacking surfaces 21, 22. The stacking surfaces 21, 22 are flat and parallel to each other. In the partial stack 4, adjacent support plates 7 abut each other with their stacking surfaces 21, 22. The centers of curvature of all grooves 12 of the partial stack 4 lie on a common axis, called the Typl main axis 23. In other words, the common centers 19 (cf. partial image TB1) of the various support plates 7 of the partial stack 4 are aligned on the Typl main axis 23.

[0128] Fig. 7 shows, in a highly schematic way, in the partial images TB1, TB2, TB3, another carrier plate 8 of type 2 in a top view (TB1, cf. corresponding viewing direction).

[0129] Gauss Fusion GmbH 07.08.2025 SP14027PCT BRI), a front view (TB2, see corresponding view BR2) and a side view (TB3, see corresponding view BR3), here with five grooves 12 (i.e., with a number of grooves AN = 5). In the side view of partial image TB3, the (regular) Type 2 main axis 24, also called center axis 24, is shown, on which the centers of curvature of all grooves 12 of the support plate 8 are arranged.

[0130] Part TB4 of Fig. 7 (in side view, analogous to TB3) shows a partial stack 5, formed here by five support plates 8 (i.e., with a corresponding number of plate layers APS = 5). The support plates 8 are concentric and each has two opposing stacking surfaces 21, 22. The stacking surfaces 21, 22 are curved and concentric with each other. In the partial stack 5, adjacent support plates 8 abut each other with their stacking surfaces 21, 22. The centers of curvature of all grooves 12 of the partial stack 5 lie on a common axis, called the common Type 2 main axis 25. In other words, the individual (regular) Type 2 main axes / center axes 24 (cf. TB3) of the different support plates 8 of the partial stack 5 coincide in the common Type 2 main axis 25.

[0131] Figure 8 shows a cross-section (perpendicular to the local longitudinal direction) through a support plate 11 of type 3 for the invention, to illustrate the use of support material within the scope of the invention. The descriptions apply accordingly to all types of support plates.

[0132] The support plate 11 has ten grooves 12 in a row 52, ​​which are accessible ("open") towards the upper side 13 shown in Fig. 8, notwithstanding the covers 16. The upper side 13 is also referred to as the groove-facing side 13, and the corresponding surface of the support plate 11 is referred to as the first outer surface 13a. Towards the lower side 14, the grooves 12 are closed by the support plate 11 and are not accessible. The lower side 14 is also referred to as the side away from the grooves 14, and the corresponding surface is referred to as the second outer surface 14a. Below the grooves 12, a cross-sectional area is thus formed.

[0133] Gauss Fusion GmbH 07.08.2025 SP14027PCT large, closed, continuous surface 26 is formed. This continuous surface 26 and the boundary structures 27 between and beside the grooves 12 consist of a support material, typically steel, and can therefore impart good mechanical strength to the support plate 11.

[0134] The conductor 15, which here has a round cross-section corresponding to the contour of a lower part of each groove 12, is arranged in the grooves 12. The conductor 15 is covered on its upper side by a cover 16; the cover 16 closes the groove 12 and is flush with the limiting structures 27 or the first outer surface 13a facing the groove. In the illustrated embodiment, the conductor 15 has an internal channel 28 for coolant. Typically, the covers 16 are welded to the remaining support plate 11 (in particular the limiting structures 27). The covers 16 also consist of support material.

[0135] The total cross-sectional area of ​​the support plate 11 (including the covers 16) occupied by support material is designated SF. The total area of ​​the conductor 15 (including the channel 28) is designated LF. According to the invention, the support plate 11 is designed such that the quotient Q = SF / (SF + LF) is Q > 0.67. In the illustrated design, Q is approximately 0.70.

[0136] Below the conductor 15, here in the area of ​​the continuous surface 26, the support plate 11 has a partial thickness ATD facing away from the groove, and above the conductor 15, the support plate 11 (including covers 16) has a partial thickness NTD facing the groove (each measured in the local stacking direction LSR). The conductors 15 have a maximum diameter GDL in the local stacking direction LSR. In the example shown, approximately ATD = 11*NTD, and approximately...

[0137] ATD = 1.1*GDL. Generally preferred are ATD>NTD or ATD>1.5*NTD or ATD>2*NTD, and ATD>0.5*GTD or ATD>1*GDL or ATD>1.25*GDL.

[0138] If desired, the conductor 15 in the groove 12 can be wrapped with an insulating tape 29 (example dotted line indicating the conductor 15 in the

[0139] Gauss Fusion GmbH 07.08.2025 SP14027PCT (Nut 12, far right). If desired, each carrier plate 11 can also be wrapped with an insulating band 30 (indicated by dotted lines).

[0140] Figure 9 in cross-section (perpendicular to the local longitudinal direction) and Figure 10 in plan view (along the local stacking direction) illustrate by way of example a partial stack 6 of support plates 11 of type 3, which are held together by means of a clamp 9. The design applies accordingly to partial stacks of other types. The partial stack 6 here comprises five support plates 11, and each support plate 11 here comprises five grooves 12.

[0141] The clamp 9 comprises an upper clamping plate 31 and a lower clamping plate 32, which are opposite each other with respect to the local stacking direction LSR, and each abuts the sub-stack 6 from the outside, here on outer stacking surfaces 21, 22 of the outer support plates 11 of the sub-stack 6.

[0142] Furthermore, the clamp 9 here includes a left pull rod 33 and a right pull rod 34. The pull rods 33, 34 protrude through the clamping plates 31, 32 here at holes 35.

[0143] The left pull rod 33 has an upper end region 36 and a lower end region 37, each with an external thread 38. The end regions 36 and 37 are therefore referred to as threaded end regions 36a and 37a. A nut 39 with an internal thread (not shown) is screwed onto each of the threaded end regions 36a and 37a. The nuts 39 engage the clamping plates 31 and 32 and clamp them in the area of ​​the left pull rod 33.

[0144] The right-hand tie rod 34 has an upper end region 40 on which an external thread 38 is formed. The end region 40 is therefore also referred to as the threaded end region 40a. A projection 42 is formed on a lower end region 41 of the right-hand tie rod 34, which engages behind the lower clamping plate 32 in the area of ​​the right-hand hole 35. The nut 39 is screwed onto the

[0145] Gauss Fusion GmbH 07.08.2025 SP14027PCT The clamping plate 31 is engaged from behind at the thread end 40a. The clamping plates 31 and 32 can be tightened in the area of ​​the right-hand drawbar 34 using the nut 39 at the thread end 40a.

[0146] Note that the tie rods 33, 34 of the illustrated designs (with a second external thread 38 or with a projection 42) can be used arbitrarily in clamps 9, i.e., in particular, only tie rods 33, only tie rods 34, or a mixture of tie rods 33, 34 as shown here. It should also be noted that more tie rods can be used in alternative designs, for example, four tie rods (then with two tie rods on each lateral side of the partial stack 6, see Fig. 18).

[0147] During the assembly of the clamp 9, a temporary clamping mechanism, also called a pre-tensioning device (not shown), is typically provided. This mechanism first compresses the partial stack 6 in the desired manner, and while the temporary clamping mechanism is in effect, the clamp 9 is mounted and tightened. The temporary clamping mechanism is then removed, and the clamp 9 alone assumes the clamping force. This simplifies the tightening of the nuts 39.

[0148] The top view in Fig. 10 illustrates typical dimensions of the sub-stack 6 or associated support plates 11 and the clamp 9. The clamp plate length KPL (along the local longitudinal direction LLR), the clamp plate width KPB (along the local transverse direction LQR), and the plate width PB, which here also represents the average plate width DPB in the plate stack, are shown. In the design shown, KPL = approximately 0.37 * DPB and KPB = 1.45 * DPB. 0.05 * DPB is generally preferred. <KPL<0,5*DPB und l,0*DPB<KPB<l,5*DPB. In anderen Bauformen kann beispielsweise auch 0,5*DPB<KPL<l*DPB oder auch 0,75*DPB<KPL<l,5*DPB gewählt werden.

[0149] Figures 11 to 14 illustrate by way of example the manufacture of a stellarator coil within the scope of the invention.

[0150] Gauss Fusion GmbH 07.08.2025 SP14027PCT As can be seen in the top view in Fig. 11, in one step a) the support plates required for each plate layer are first manufactured; three manufactured support plates 7, 8, 11 are illustrated here as examples (see also Fig. 3-5 analogously). The support plates 7, 8, 11 are initially separate from each other. A special feature is that webs 43 remain at the ends 44 of the grooves 12. In other words, the grooves 12 are not yet completely milled through (along the local longitudinal direction LLR) towards their ends 44.

[0151] Then, in step b), the support plates 7, 8, 11 of the respective plate layer are placed next to each other in a ring shape and welded together. Since the webs 43 remain at the ends of the grooves 12, smooth, unprofiled end faces of the support plates 7, 8, 11 can be welded together, which is particularly simple and reliable, and especially mechanically robust. Fig. 12 shows the situation after welding.

[0152] Then, in step c), the remaining webs are removed. In other words, the grooves 12 are now milled to their full length along the local longitudinal direction LLR. Fig. 13 shows the support plates 7, 8, 11 with the grooves 12 now completely milled through.

[0153] Then, in step d), the conductors can be inserted (not shown in detail here, but see Fig. 3). Depending on whether the conductor is plastically deformable or not, it can be bent into the required shape beforehand or during this process, or it may need to be manufactured in the required shape from the outset (not illustrated in detail). Typically, the filled grooves are then closed with a cover (see again Fig. 3).

[0154] Subsequently, in step e), the individually manufactured plate layers 3 are stacked, i.e., placed next to each other, as illustrated in Fig. 14. The direction 51, along which the plate layers 3 are guided towards each other during stacking, typically corresponds approximately to the axis 50 of the stellarator coil (see also Fig. 1). All local stacking directions occurring in the stellarator coil have a component along direction 51.

[0155] Gauss Fusion GmbH 07.08.2025 SP14027PCT When the plate layers 3 are placed next to each other, a plate layer stack 2 is created. The plate layer stack 2 comprises a plurality of sub-stacks of carrier plate components. The plate layer stack 2 is also clamped together with several clamps (not illustrated in Fig. 14, but see Fig. 9 and Fig. 10).

[0156] Fig. 15 in a schematic top view and Fig. 16 in a schematic cross-section (central and perpendicular to the toroidal direction) illustrate an exemplary stellarator 45 for the invention.

[0157] The stellarator 45 is essentially toroidal in shape. The stellarator 45, together with a plasma vessel 46, encloses an essentially toroidal plasma volume 47. A plurality of 3D-shaped, non-planar stellarator coils 1 are arranged around the plasma volume 47 in a toroidal direction 53. Each stellarator coil 1 forms a poloidal ring around the plasma volume 47 at its toroidal position. The stellarator coils 1 are, in turn, arranged in a cryostat 48 to provide thermal insulation and thus maintain the stellarator coils 1 (or more precisely, their superconducting conductors) at cryogenic temperatures. The plate stack 2 and the terminals 9 can be built directly within the cryostat 48; in particular, no housing is required for the mechanical stabilization of the plate stack 2.For the sake of simplicity, the external support of the individual stellarator coils 1 on the ground and against each other is not shown in detail here.

[0158] Fig. 17 shows a schematic top view of a support plate 11, here of type 3, on which a so-called change of winding is formed, for the invention. The descriptions apply accordingly to other types of support plates.

[0159] In the example shown, ten grooves 12 are provided in each plate layer, in which the conductor (not shown separately) is to be wound spirally; see also positions PI to P10 of the grooves 12. The carrier plate 11 has a first end EE (relative to the local longitudinal direction LLR).

[0160] Gauss Fusion GmbH 07.08.2025 SP14027PCT and a second end ZE, with further support plates of the associated plate layer attached to these ends EE, ZE (not shown in detail, but see e.g. Fig. 2).

[0161] At the first end EE, from position PI, a groove 12 leads through the support plate 11 to position P2 at the second end ZE. Furthermore, at the first end EE, from position P2, a groove 12 leads to position P3 at the second end ZE, and so on.

[0162] A groove start 54, which leads to the first position PI at the second end ZW, begins at a conductor feed point 55. At this point 55, the conductor can be inserted from the outside or from an adjacent plate layer (depending on the location of the plate layer in the stack).

[0163] A slot end 56, originating from a tenth position P10 at the first end EE, leads to a conductor exit point 57. At this point 57, the conductor can be transferred to the outside (depending on the location of the plate layer in the stack) or routed to an adjacent plate layer.

[0164] Since the change of winding for the plate layer is concentrated (and limited) to the support plate 11 shown, the remaining support plates of the plate layer can be formed normally, i.e. without a change of winding (as shown, for example, in Fig. 3).

[0165] Fig. 18 shows a further embodiment of a stellarator coil 1 according to the invention. Only the essential differences to the design of Fig. 1 (and Fig. 9, Fig. 10) are explained.

[0166] In the illustrated configuration, the clamps 9 are each equipped with four tie rods 33a, 33b, 34a, 34b, which clamp the clamping plates 31, 32 together. Two tie rods are arranged on each side of the clamped sub-stack, as shown here (see the two tie rods on the left).

[0167] Gauss Fusion GmbH 07.08.2025 SP14027PCT 33a, 33b (mostly obscured), and the two right-hand tie rods 34a, 34b.

[0168] Furthermore, the clamping plates 31, 32 are designed here with a comparatively large clamping plate length (KPL). Compared to the average plate width (DPB) of the plate layer stack 2, KPL = approximately 0.75 * DPB.

[0169] In summary, the invention relates to a 3D-shaped stellarator coil (1) for a nuclear fusion device, which is constructed from stacked plate layers (3), wherein each plate layer (2) has ring-shaped, connected support plates (7, 8, 11). Grooves (12) are arranged in the support plates (7, 8, 11) in which a superconducting conductor (15) runs. For each support plate (7, 8, 11), in cross-section perpendicular to a local longitudinal direction (LLR.) of the grooves (12), the area SF occupied by the support material of the support plate (7, 8, 11) and the area LF occupied by the conductor (15) in the grooves (12) are such that SF / (SF+LF)>0.67. The stack of plate layers (2) is held together by spaced-apart clamps (9) so that the support plates (7, 8, 11) and the clamps (9) together form a support structure (10) to absorb the magnetic forces during operation.Each layer of plates (3) is composed exclusively of carrier plates (7, 8, 11) of the following three types:.

[0170] - Type 1 carrier plate (7), wherein grooves (12) are curved only in a common plate plane (17),

[0171] - Type 2 carrier plate (8), wherein grooves (12) are curved only in mutually parallel transverse planes (18),

[0172] - Type 3 carrier plate (11), wherein grooves (12) run straight. The stellarator coil according to the invention is simple and inexpensive to manufacture.

[0173] Gauss Fusion GmbH 07.08.2025 SP14027PCT

[0174] 1 Stellarator coil

[0175] 2 plate layer stacks

[0176] 3-layer plate

[0177] 4 partial stacks (Type 1 carrier partial plates)

[0178] 5 partial stacks (Type 2 carrier partial plates)

[0179] 6 partial stacks (Type 3 carrier partial plates)

[0180] 7 Carrier plate type 1

[0181] 8 Carrier plate type 2

[0182] 9 terminal

[0183] 10 Support structure

[0184] 11 Carrier plate type 3

[0185] 12 grooves

[0186] 13 groove-facing side

[0187] 13a first outdoor area

[0188] 14 side facing away from the groove

[0189] 14a second outdoor area

[0190] 15 ladders

[0191] 16 covers

[0192] 17 common plate plane (Type 1 support plate)

[0193] 18 transverse planes

[0194] 19 common center point of the grooves of the type 1 support part plate

[0195] 21 stacking area

[0196] 22 stacking area

[0197] 23 common type main axis of the substack

[0198] 24 (regular) Type 2 main axis (center axis) of the Type 2 support plate

[0199] 25 common type 2 main axis of the substack

[0200] 26 continuous area

[0201] 27 Boundary structures

[0202] 28-channel

[0203] 29 insulating tape (for conductors)

[0204] Gauss Fusion GmbH 07.08.2025 SP14027PCT 30 insulating tape (for plate layer or associated carrier plates)

[0205] 31 (upper) clamping plate

[0206] 32 (lower) clamping plate

[0207] 33 (left) pull rod

[0208] 33a, 33b (left) pull rods

[0209] 34 (right) pull rod

[0210] 34a, 34b (right) pull rods

[0211] 35 holes

[0212] 36 End range

[0213] 36a Thread end area

[0214] 37 End area

[0215] 37a Thread end area

[0216] 38 external threads

[0217] 39 Mother

[0218] 40 End range

[0219] 40a Thread end area

[0220] 41 End area

[0221] 42 Cantilever

[0222] 43 footbridges

[0223] 44 ends of the grooves

[0224] 45 Stellarator

[0225] 46 Plasma vessel

[0226] 47 Plasma volume

[0227] 48 Cryostat

[0228] 49 common plate plane (Type 3 support plate)

[0229] 50 Axis of the stellarator coil

[0230] 51 Direction of placing the plate layers next to each other

[0231] 52nd row

[0232] 53 toroidal direction

[0233] 54 Groove start

[0234] 55 Ladder feed point

[0235] 56 Groove end

[0236] Gauss Fusion GmbH 07.08.2025 SP14027PCT 57 Ladder Execution Point

[0237] AA (individual) distance between terminals

[0238] ATD groove-facing partial thickness

[0239] BR1-BR3 Viewing directions

[0240] DAA average distance between terminals

[0241] DPB average plate width

[0242] DPD average sheet thickness

[0243] DPL average sheet length

[0244] EE first end

[0245] KPB clamping plate width

[0246] KPL clamping plate length

[0247] GDL largest diameter of the conductor

[0248] LSR. local stacking direction

[0249] LLR local longitudinal direction

[0250] LQR local transverse direction

[0251] NTD groove-side partial thickness

[0252] PB (individual) plate width

[0253] PD (individual) plate thickness

[0254] PL (individual) plate length

[0255] P1-P10 positions of the slots

[0256] TB1-TB4 partial images

[0257] ZE second end

[0258] Gauss Fusion GmbH 07.08.2025 SP14027PCT

Claims

Patent claims 1. Stellarator coil (1) for a nuclear fusion device, wherein the stellarator coil (1) is designed as a non-planar, 3D-shaped, annular coil, and wherein the stellarator coil (1) comprises a superconducting conductor (15) wound with a plurality of turns, and a support structure (10) suitable for mechanically stabilizing the stellarator coil (1) under the influence of magnetic forces on the conductor (15) during operation of the stellarator coil (1), wherein a plurality of annular plate layers (3) are provided, in each of which several of the turns of the conductor (15) are wound, wherein in each plate layer (3) a plurality of sub-plates are arranged annularly one after the other and successive sub-plates are attached to one another in each plate layer (3), and wherein the plate layers (3) form a plate layer stack (2) and successive plate layers (3) abut one another.wherein each sub-plate forms several grooves (12) into which the conductor (15) is inserted, wherein the grooves (12) of the sub-plate extend along a local longitudinal direction (LLR), and the grooves (12) of the sub-plate are arranged successively in a local transverse direction (LQR), wherein a local stacking direction (LSR) is perpendicular to the local longitudinal direction (LLR) and perpendicular to the local transverse direction (LQR), and wherein the grooves (12) of successive sub-plates of a plate layer (3) adjoin one another, characterized in that Gauss Fusion GmbH 07.08.2025 SP14027PCT that the sub-plates are designed as support sub-plates (7, 8, 11), wherein, for each support sub-plate (7, 8, 11) in cross-section perpendicular to the local longitudinal direction (LLR), for an area SF occupied by support material of the support sub-plate (7, 8, 11) and an area LF occupied by the conductor (15) in the grooves (12), the following applies: SF / (SF+LF)>0.67; that the support structure (10) is formed by - the support plates (7, 8, 11) of the plate layers (3) as well as by - several clamps (9) distributed and spaced apart along a circumference of the stellarator coil (1), with which the plate layers (3) are clamped, and that each plate layer (3) is exclusively composed of support plates (7, 8, 11) of the following three types: - Type 1 support plate (7), wherein in each type 1 support plate (7) its grooves (12) are only in a common plate plane (17) are curved, wherein this common plate plane (17) contains the local longitudinal direction (LLR.) and the local transverse direction (LQR), and whose grooves (12) are curved with respect to a common center point (19), - Type 2 support plate (8), wherein in each type 2 support plate (8) the grooves (12) are only in transverse planes parallel to each other (18) are curved, wherein these parallel transverse planes (18) contain the local longitudinal direction (LLR) and are perpendicular to the local transverse direction (LQR), and whose grooves (12) have a common radius of curvature, - Type 3 support plate (11), wherein the grooves (12) of each type 3 support plate (11) are straight, and wherein each plate layer (3) has at least several type 1 support plates (7) and several type 2 support plates (8).

2. Stellarator coil (1) according to claim 1, characterized in that, Gauss Fusion GmbH 07.08.2025 SP14027PCT that each carrier plate (7, 8, 11) has one or two stacking surfaces (21, 22) which are at least substantially perpendicular to the local stacking direction (LSR).) are designed such that in a respective type 1 support plate (7) one or two stacking surfaces (21, 22) are formed flat and parallel to the common plate plane (17) of the type 1 support plate (7), that in a respective type 2 support plate (8) a) one or two stacking surfaces (21, 22) are formed curved about a type 2 principal axis (24) on which the centers are also located with respect to which the grooves (12) of the type 2 support plate (8) are curved, wherein the type 2 principal axis (24) is parallel to the local transverse direction (LQR), and b) one or two stacking surfaces (21, 22) are formed parallel to the local transverse direction (LQR), and that in a respective type 3 support plate (11) one or two stacking surfaces (21, 22) are formed flat and parallel to a common plate plane (49) of the type 3 support plate (11) are formed, wherein the common plate plane (49) contains the local longitudinal direction (LLR) and the local transverse direction (LQR).

3. Stellarator coil (1) according to one of the preceding claims, characterized in that the plate layer stack (2) forms sub-stacks (4, 5, 6), wherein in each sub-stack (4, 5, 6) only support plates (7, 8, 11) of one of the three types are stacked, wherein in each sub-stack (4) of type 1 support plates (7) a) the associated plate planes (17) are all parallel to each other and b) the associated center points (19) of the grooves (12), with respect to which the grooves (12) of the support plates (7) of this sub-stack (4) are curved, all lie on a common type principal axis (23) which runs perpendicular to the plate planes (17), Gauss Fusion GmbH 07.08.2025 SP14027PCT wherein in a respective sub-stack (5) of type 2 support plates (8) the associated centers of the grooves (12), with respect to which the grooves (12) of the support plates (8) of this sub-stack (5) are curved, all lie on a common type 2 principal axis (25) which runs parallel to the local transverse direction (LQR), and wherein in a respective sub-stack (6) of type 3 support plates (11) associated common plate planes (49) are all parallel to each other, wherein a respective common plate plane (49) of a type 3 support plate (11) contains the local longitudinal direction (LLR) and the local transverse direction (LQR).

4. Stellarator coil (1) according to one of the preceding claims, characterized in that at least a subset of the successive support plates (7, 8, 11) in a respective plate layer (3) are welded together.

5. Stellarator coil (1) according to one of the preceding claims, characterized in that one or more covers (16) are arranged and fixed on each of the support plates (7, 8, 11), with which the inserted conductor (15) is covered and fixed in the grooves (12), in particular wherein the cover (16) or the covers (16) are welded to the support plate (7, 8, 11).

6. Stellarator coil (1) according to one of the preceding claims, characterized in that the conductor (15) inserted into the slots (12) is provided with electrical insulation, in particular wherein the conductor (15) is wrapped with one or more insulating tapes (29).

7. Stellarator coil (1) according to one of the preceding claims, characterized in that the plate layers (3) are electrically insulated from each other, Gauss Fusion GmbH 07.08.2025 SP14027PCT in particular wherein the support plates (7, 8, 11) of a respective plate layer (3) are wrapped with one or more electrically insulating tapes (30).

8. Stellarator coil (1) according to one of the preceding claims, characterized in that a cross-sectional profile of the slots (12) perpendicular to the local longitudinal direction (LLR.) in a respective support plate (7, 8, 11) remains constant along its plate length (PL), irrespective of any changes in the winding of slots (12) and / or any changes in the plate layer.

9. Stellarator coil (1) according to one of the preceding claims, characterized in that a change of turns is provided in a respective plate layer (3) on one of the support part plates (7, 8, 11).

10. Stellarator coil (1) according to one of the preceding claims, characterized in that a number of AN grooves (12) are arranged successively in a transverse direction (LQR.) in a respective support plate (7, 8, 11), with 5 <AN<20, bevorzugt 6<AN<15, besonders bevorzugt 8<AN<12.

11. Stellarator coil (1) according to one of the preceding claims, characterized in that a number of APS of plate layers (3) form the plate layer stack (2), with 5 <APS<20, bevorzugt 6<APS<15, besonders bevorzugt 8<APS<12.

12. Stellarator coil (1) according to one of the preceding claims, characterized in that SF / (SF+LF)>0.75, Gauss Fusion GmbH 07.08.2025 SP14027PCT Preferably SF / (SF+LF)>0.

80.

13. Stellarator coil (1) according to one of the preceding claims, characterized in that in each support plate (7, 8, 11) exactly one row (52) of grooves (12) is formed, which are arranged successively in the transverse direction (LQR), and that the grooves (12) of this exactly one row (52) are open to the same side (13) of the support plate (7, 8, 11), irrespective of any cover (16) closing each groove (12).

14. Stellarator coil (1) according to claim 13, characterized in that, for a respective support plate (7, 8, 11) in cross-section perpendicular to the local longitudinal direction (LLR), the following applies to a partial thickness NTD of the support plate (7, 8, 11) on the slot-side between the conductors (15) of exactly one row (52) and a first outer surface (13a), in particular a stacking surface (22), of the support plate (7, 8, 11) on the side (13) towards which the slots (12) are open, and to a partial thickness ATD of the support plate (7, 8, 11) on the side opposite the slots between the conductors (15) of exactly one row (52) and an outer surface (14a), in particular a stacking surface (21), of the support plate (7, 8, 11) on the side (14) towards which the slots (12) are not open: ATD>NTD, preferably ATD>1.5*NTD, especially preferred ATD>2*NTD.

15. Stellarator coil (1) according to one of claims 13 or 14, characterized in that in a respective support plate (7, 8, 11) the cross-section is perpendicular to the local longitudinal direction (LLR) Gauss Fusion GmbH 07.08.2025 SP14027PCT For a partial thickness ATD of the carrier plate (7, 8, 11) facing away from the grooves between the conductors (15) of exactly one row (52) and an outer surface (14a), in particular a stacking surface (21), of the carrier plate (7, 8, 11) on the side (14) to which the grooves (12) are not open, and a maximum diameter GDL of the conductors (15) along the local stacking direction (LSR), the following applies: ATD>0.5*GDL, preferably ATD>1*GDL, particularly preferably ATD>1.25*GDL.

16. Stellarator coil (1) according to one of the preceding claims, characterized in that the support plates (7, 8, 11) of a respective plate layer (3) have a uniform plate thickness PD in the local stacking direction (LSR), preferably wherein the support plates (7, 8, 11) of all plate layers (3) have a uniform plate density PD in the local stacking direction (LSR), and preferably wherein the support plates (7, 8, 11) of all plate layers (3) have a uniform plate width PB in the local transverse direction (LQR).

17. Stellarator coil (1) according to one of the preceding claims, characterized in that the terminals (9) have an average distance DAA from each other in the circumferential direction, and the support plates (7, 8, 11) of the stellarator coil (1) have an average plate width DPB along the local transverse direction (LQR), and that: DAA>3*DPB, preferably DAA>5*DPB. Gauss Fusion GmbH 07.08.2025 SP14027PCT 18. Stellarator coil (1) according to one of the preceding claims, characterized in that each terminal (9) comprises: - two clamping plates (31, 32) which are located at a circumferential position of the stellarator coil (1) and are located on the outside of a lowest plate layer (3) and an uppermost plate layer (3) of the plate layer stack (2), - a number M tie rods (33; 33a-33b; 34; 34a-34b), with M>2, preferably M>4, wherein each tie rod (33; 33a-33b; 34; 34a-34b) has one or two end regions (36, 37, 40) provided with a thread (38), hereinafter referred to as threaded end regions (36a, 37a, 40a), wherein each threaded end region (36a, 37a, 40a) projects through a recess in one of the clamping plates (31, 32), and the threaded end region (36a, 37a, 40a) is clamped against the clamping plate (31, 32) by a nut (39), wherein the nut (39) engages behind the clamping plate (31, 32).

19. Stellarator (45) for a nuclear fusion device, suitable for the magnetic confinement of a substantially toroidal plasma volume (47), wherein the stellarator (45) comprises a plurality of stellarator coils (1) according to one of the preceding claims, wherein the stellarator coils (1) are arranged distributed in the toroidal direction (53) of the plasma volume (47), and wherein each stellarator coil (1) locally encloses the toroidal plasma volume (47) in a ring-like manner.

20. Stellarator (45) according to claim 19, characterized in that in a respective stellarator coil (1) all occurring local stacking directions (LSR) are aligned with a directional component along the local toroidal direction (53). Gauss Fusion GmbH 07.08.2025 SP14027PCT 21. Stellarator (45) according to claim 19 or 20, characterized in that the stellarator (45) further comprises a cryostat (48), wherein a respective stellarator coil (1) is arranged in the cryostat (48) without a housing.

22. Method for manufacturing a stellarator coil (1) according to any one of claims 1 to 18, comprising the following steps: Step a) the support plates (7, 8, 11) required for the stellarator coil (1) are manufactured, including at least several type 1 support plates (7) and several type 2 support plates (8), wherein at least a subset of the support plates (7, 8, 11) have webs (43) remaining at the ends (44) of the grooves (12); Step b) the support plates (7, 8, 11) of a respective plate layer (3) are arranged successively in a ring shape, and at least in a subset of the support plates (7, 8, 11) butt joints are welded together, with webs (43) remaining at the ends (44) of the grooves (12) at these welded joints; Step c) The remaining webs (43) are removed, in particular by milling; Step d) The conductor (15) is inserted into the grooves (12); Step e) The plate layers (3) are placed next to each other and clamped together.

23. Method according to claim 22, characterized in that in step d) covers (16) are further arranged on the support plates (7, 8, 11) with which the inserted conductor (15) is fixed in the grooves (12), in particular wherein the covers (16) are welded to the support plates (7, 8, 11). Gauss Fusion GmbH 07.08.2025 SP14027PCT 24. Method according to claim 22 or 23, characterized in that the conductor (15) is first manufactured, and after its manufacture is bent into a shape which corresponds to the required shape in the stellarator coil (1) before or during step d).

25. Method according to claim 22 or 23, characterized in that the conductor (15) is produced directly in a mold which corresponds to the required shape in the stellarator coil (1) before step d). Gauss Fusion GmbH 07.08.2025 SP14027PCT

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