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DE-102024133109-A1 - Magnetic coil, especially for a nuclear fusion plant, with simplified manufacturing, assembly and disassembly

DE102024133109A1DE 102024133109 A1DE102024133109 A1DE 102024133109A1DE-102024133109-A1

Abstract

The invention relates to a magnetic coil (1, 1a) comprising several ring-shaped, stacked plate layers (3; 3a-3h), each plate layer being composed of successively attached sub-plates (5; 5a-5c; 9, 9a, 9b), wherein grooves (16, 21) extend into the sub-plates in which superconducting conductors (22) are inserted, wherein several sections (ES, wES, WS, WS1-WS3, ZS, AS) are present, each forming a part of the circumference of the magnetic coil and being connected by stack joints (SJ1-SJ3), each stack joint comprising a plate layer joint (6; 6a-6h) in each plate layer, the sections comprising at least one insertion section (ES, wES), wherein in the insertion section a) either from only one stack end (OSE) with respect to all partial plate layers (8; 8a-8e), b) or from a first stack end (SE1) for a first part (45) of the partial plate layers (8; 8a-8d) and from a second, opposite stack end (SE2) for a second, remaining part (46) of the partial plate layers (8; 8e-8h), a length (L8a-L8h) of the sub-plate layers decreases towards the next inner plate layer, and wherein in the stack joints belonging to the insertion section each i) the plate layer joints are offset from each other, and ii) with respect to the associated stack end face (OSE; SE1, SE2) according to a) or b) the plate layer joints of more inwardly located plate layers do not overlap with the sub-plates of more outwardly located plate layers of the next section. The magnetic coil is easier to handle during manufacturing, assembly, disassembly, and any repairs or maintenance.

Inventors

  • Neil Mitchell

Assignees

  • Gauss Fusion GmbH

Dates

Publication Date
20260513
Application Date
20241112

Claims (20)

  1. Magnetic coil (1, 1a), in particular a stellarator coil or tokamak coil for a nuclear fusion device, wherein a plurality of annular plate layers (3; 3a-3h) are provided, in each of which several turns of a superconducting conductor (22) are formed, wherein in each plate layer (3; 3a-3h) a plurality of sub-plates (5; 5a-5c; 9, 9a, 9b) are arranged annularly one after the other and in each plate layer (3; 3a-3h) successive sub-plates (5; 5a-5c; 9, 9a, 9b) are attached to one another, and wherein the plate layers (3; 3a-3h) form an annular plate layer stack (4) and successive plate layers (3; 3a-3h) abut one another, wherein each sub-plate (5; 5a-5c; 9, 9a, 9b) has several grooves (16, 21) forms, into which the conductor (22) is inserted, wherein the grooves (16, 21) of the sub-plate (5; 5a-5c; 9, 9a, 9b) extend along a local longitudinal direction (LLR), and the grooves (16, 21) of the sub-plate (5; 5a-5c; 9, 9a, 9b) 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 (16, 21) of successive sub-plates (5; 5a, 5b, 5c; 9, 9a, 9b) of a plate layer (3; 3a-3h) are aligned with each other, and in particular connect to each other, characterized in that the plate layer stack (4) comprises several sections (ES, wES; WS; WS1, WS2, WS3; ZS, AS) each form a part of the circumference of the annular plate-layer stack (4), wherein each section (ES, wES; WS; WS1, WS2, WS3; ZS, AS) is formed by a stack (7) of partial plate layers (8; 8a-8h, 43a-43h, 44a-44h, 47a-47h), wherein a partial plate layer (8; 8a-8h, 43a-43h, 44a-44h, 47a-47h) is formed by the partial plates (5; 5a-5c; 9, 9a, 9b) of the section (ES, wES; WS; WS1, WS2, WS3; ZS, AS) in a plate layer (3; 3a-3h), wherein in the annular In a stack of plate layers (4), successive sections (ES, wES; WS; WS1, WS2, WS3; ZS, AS) are connected to each other by stack joints (SJ1, SJ2, SJ3), such that each stack joint (SJ1, SJ2, SJ3) comprises a plate layer joint (6; 6a-6h) in each plate layer (3; 3a-3h), wherein each plate layer joint (6; 6a-6h) in its associated plate layer (3; 3a-3h) electrically contacts the conductors (22) in the slots (16) of an end-face sub-plate (9, 9a) of a first section (ES) with opposing conductors (22) in the slots (21) of an end-face sub-plate (9, 9b) of a second section (WS) by several conductor joints (11; 11a-11d), and the end-face sub-plate (9, 9a) of the first section (ES) is attached to the end-face sub-plate (9, 9b) of the second section (WS), and that the sections (ES, wES; WS; WS1, WS2, WS3; ZS, AS) comprise at least one insertion section (ES, wES), wherein in the insertion section (ES, wES) a) either from only one stack end (OSE) along a common sequence direction (AR) with respect to all sub-plate layers (8; 8a-8e), b) or from a first stack end (SE1) along a first sequence direction (AR1) for a first part (45) of the sub-plate layers (8; 8a-8d) and from a second, opposite stack end (SE2) along a second, opposite sequence direction (AR2) for a second, remaining part (46) of the sub-plate layers (8; 8e-8h), a length (L8a-L8h) of the partial plate layers (8; 8a-8h) measured along the local longitudinal direction (LLR) into the plate layer stack (4) decreases towards the next inner plate layer (3; 3a-3h), wherein in the stack joints (SJ1, SJ2, SJ3) belonging to the insertion section (ES, wES) i) the plate layer joints (6; 6a-6h) are arranged offset from each other with respect to the local longitudinal direction (LLR), and ii) in the plate layer stack (4) with respect to the associated stack end side (OSE; SE1, SE2) according to a) or b) the plate layer joints (6; 6a-6h) of more inner plate layers (3; 3a-3h) are not connected to the partial plates (5; 5a-5c; 9, 9a, 9b) of more outer plate layers (3; 3a-3h) of the section (WS; WS1, WS2, WS3; ZS) overlap, which is connected to the insertion section (ES, wES) at the stack joint (SJ1, SJ2, SJ3).
  2. magnetic coil (1, 1a) according to Claim 1 , characterized in that, in the stack joints (SJ1, SJ2, SJ3) belonging to the at least one insertion section (ES, wES), the end-face sub-plates (9, 9a) of the insertion section (ES, wES) and the end-face sub-plates (9, 9b) of the section (WS; WS1, WS2, WS3, ZS) connected to the insertion section (ES, wES) at the stack joint (SJ1, SJ2, SJ3) are detachably fastened to one another at a respective plate layer joint (6; 6a-6h) and the conductor joints (11; 11a-11d) are detachably electrically contacted, wherein the loosening of this fastening and the loosening of these electrical contacts of the conductor joints (11; 11a-11d) from the associated stack end (OSE, SE1, SE2) can be carried out according to a) or b).
  3. Magnetic coil (1, 1a) according to one of the preceding claims, characterized in that the sections (ES, wES; WS; WS1, WS2, WS3; ZS, AS) include several insertion sections (ES, wES).
  4. A magnetic coil (1, 1a) according to one of the preceding claims, characterized in that the sections (ES, wES; WS; WS1, WS2, WS3; ZS, AS) further comprise at least one intermediate section (ZS) and one connecting section (AS), wherein the intermediate section (ZS) follows the insertion section (ES, wES) in the annular plate-layer stack (4), and the connecting section (AS) follows the intermediate layer (ZS), wherein at the stack joint (SJ3) which connects the intermediate section (ZS) with the connecting section (AS), i') the plate-layer joints (6; 6a-6h) are arranged offset from one another with respect to the local longitudinal direction (LLR), and ii') in the plate-layer stack (4) with respect to the associated stack end side (OSE; SE1, SE2) according to a) or b) of the insertion section (ES, wES), which follows the intermediate section (ZS), the plate layer joints (6; 6a-6h) of more inwardly located plate layers (3; 3a-3h) do not overlap with the sub-plates (5; 5a-5c; 9, 9a, 9b) of more outwardly located plate layers (3; 3a-3h) of the connecting section (AS).
  5. magnetic coil (1, 1a) according to one of the Claims 1 until 4 , characterized in that in the insertion section (ES, wES) from only one stack end side (OSE) with respect to all plate layers (3; 3a-3e) a length (L8a-L8h) of the partial plate layers (8; 8a-8h) measured along the local longitudinal direction (LLR) into the plate layer stack (4) decreases towards the next inner plate layer (3; 3a-3h).
  6. magnetic coil (1, 1a) according to one of the Claims 1 until 4 , characterized in that in the insertion section (ES, wES) from a first stack end side (SE1) for a first part (45) of the partial plate layers (8; 8a-8d) and from a second, opposite stack end side (SE2) for a second, remaining part (46) of the partial plate layers (8; 8e-8h) a length (L8a-L8h) of the partial plate layers (8; 8a-8h) measured along the local longitudinal direction (LLR) into the plate layer stack (4) decreases towards the next inner plate layer (3; 3a-3h).
  7. A magnetic coil (1, 1a) according to one of the preceding claims, characterized in that different types (22a, 22b) of superconducting conductor (22) are installed within at least one plate layer (3; 3a-3h) of the plate layer stack (4), such that different types (22a, 22b) of superconducting conductor (22) are electrically contacted with each other at at least one plate layer joint (6; 6a-6h) of the plate layer (3; 3a-3h) at at least one conductor joint (11; 11a-11d), in particular wherein - the superconducting conductor (22) in a first section (ES) and the superconducting conductor (22) in a second section (WS) are partially or completely of different types (22a, 22b), and/or - in at least one section (ES, wES; WS; WS1, WS2, WS3; ZS, AS) or all sections (ES, wES; WS; WS1, WS2, WS3; ZS, AS) within a respective partial plate layer (8; 8a-8h, 43a-43h, 44a-44h, 47a-47h) the superconducting conductor (22) in a radially inner part of the slots (16; 21) and the superconducting conductor (22) in a radially outer part of the slots (16; 21) are of different types (22a, 22b).
  8. Magnetic coil (1, 1a) according to one of the preceding claims, characterized in that several clamps (56) are distributed and spaced apart around the circumference of the magnetic coil (1, 1a), with which the plate layers (3; 3a-3h) are clamped against each other, in particular detachably clamped.
  9. magnetic coil (1, 1a) according to Claim 8 , characterized in that the sub-plates (5; 5a-5c; 9, 9a, 9b) are designed as support sub-plates (58), wherein, in a respective support sub-plate (58) in cross-section perpendicular to the local longitudinal direction (LLR), the following applies to an area SF occupied by support material (59) of the support sub-plate (58) and an area LF occupied by the conductor (22) in the grooves (16, 21): SF / ( SF + LF ) ≥ 0,50, bevorzugt SF / ( SF + LF ) ≥ 0,67, and that the support plates (58) and the clamps (56) together form a support structure (60) of the magnetic coil (1, 1a), suitable for mechanical stabilization of the magnetic coil (1, 1a) under the influence of magnetic forces on the conductor (22) during operation of the magnetic coil (1; 1a).
  10. Magnetic coil (1, 1a) according to one of the preceding claims, characterized in that in each subplate (5; 5a-5c; 9, 9a, 9b) exactly one row (50) of grooves (16, 21) is formed, which are arranged successively in the local transverse direction (LQR).
  11. Magnetic coil (1, 1a) according to one of the preceding claims, characterized in that at a respective plate layer joint (6; 6a-6h) at a respective conductor joint (11; 11a-11d) an end section (15) of the conductor (22) of the first section (ES) and an end section (23) of the conductor (22) of the second section (WS) overlap along the local longitudinal direction (LLR), and that a joint clamping device (37) is provided the is, with which a clamping force (36) is exerted transversely to the local longitudinal direction (LLR) at least on the overlapping end sections (15, 23).
  12. magnetic coil (1, 1a) according to Claim 11 , characterized in that in a respective conductor joint (11; 11a-11d) the end section (15) of the conductor (22) of the first section (ES) is chamfered with a first cut surface (25) and the end section (23) of the conductor (22) of the second section (WS) is chamfered with a second cut surface (26), wherein the cut surfaces (25, 26) are inclined to a direction of a longitudinal extension of the respective conductor (22), and the cut surfaces (25, 26) have equal chamfer angles α relative to the direction of the longitudinal extension, and that the two cut surfaces (25, 26) are arranged parallel to each other and facing each other.
  13. magnetic coil (1, 1a) according to Claim 11 or 12 , characterized in that in each conductor joint (11; 11a-11d) the joint clamping device (37) comprises at least one joint clamping element (33) which is pressed against at least one of the overlapping conductors (22), in particular wherein the joint clamping element (33) is screwed in place.
  14. Magnetic coil (1, 1a) according to one of the preceding claims, characterized in that several grooves (16) are formed in the end-side partial plate (9, 9a) of the first section (ES) at a respective plate layer joint (6; 6a-6h), in which conductors (22) are each inserted, and several grooves (21) are formed in the end-side partial plate (9, 9b) of the second section (WS), in which conductors (22) are each inserted, and that the two end-side partial plates (9, 9a, 9b) are detachably fastened to one another by an overlapping connection (61).
  15. magnetic coil (1, 1a) according to Claim 14 , characterized in that the end-side partial plate (9, 9a) of the first section (ES) and the end-side partial plate (9, 9b) of the second section (WS) are screwed together, wherein screws (39) extend at least in some spaces between successive grooves (16, 21) along the local transverse direction (LQR), in particular wherein end-side partial plates (9, 9a, 9b) of a partial plate layer (8; 8a-8h; 43a-43h; 44a-44h; 47a-47h), which are involved in forming plate layer joints (6; 6a-6h), have at their end facing the plate layer joint (6; 6a-6h) a larger plate width JPB measured along the local transverse direction (LQR) than a normal plate width NPB present at their end facing away from the plate layer joint (6; 6a-6h) and/or the exhibits a majority of the subplates (5; 5a-5c; 9, 9a, 9b) of the associated plate layer (3; 3a-3h).
  16. magnetic coil (1, 1a) according to Claim 14 or 15 , characterized in that in the area of the overlap connection (61) the end-side partial plates (9, 9a, 9b) each have an exposed end (17, 28) in which the grooves (16, 21) are opened towards the respective other end-side partial plate (9, 9a, 9b), wherein at least one projection (14, 19) and a recess (13, 20) are formed at the exposed end (17, 28), and wherein a projection (14, 19) of a respective end-side partial plate (9, 9a, 9b) is hooked into a recess (13, 20) of the respective other end-side partial plate (9, 9a, 9b).
  17. magnetic coil (1, 1a) according to Claim 16 , characterized in that a wedge element (24) is clamped in the recess (13) of the end-side partial plate (9, 9a) of the first section (ES) between the projection (19) of the partial plate (9, 9b) of the second section (WS) and an unexposed section (17a) of the end-side partial plate (9, 9a) of the first section (ES), so that the projections (14, 19) of the two end-side partial plates (9, 9a, 9b) are pressed against each other, and/or vice versa.
  18. A magnetic coil arrangement (51), in particular a stellarator or a tokamak, for a nuclear fusion device, wherein the magnetic coil arrangement (51) is suitable for the magnetic confinement of an at least substantially toroidal plasma volume (53), wherein the magnetic coil arrangement (51) comprises a plurality of magnetic coils (1, 1a), in particular stellarator coils or tokamak coils, wherein the magnetic coils (1, 1a) are arranged distributed in the toroidal direction (54) of the plasma volume (53), wherein the magnetic coils (1, 1a) locally enclose the toroidal plasma volume (53) in a ring-like manner, and wherein at least one of these magnetic coils (1, 1a) is arranged according to one of the Claims 1 until 17 is trained.
  19. Method for manufacturing a magnetic coil (1, 1a) according to one of the Claims 1 until 17 is constructed in that the partial plate layers (8; 8a-8h, 43a-43h, 44a-44h, 47a-47h) are each manufactured in the following steps: S1) the partial plates (5; 5a-5c; 9, 9a, 9b) of the partial plate layer (8; 8a-8h, 43a-43h, 44a-44h, 47a-47h) are arranged successively and fastened together, wherein the grooves (16; 21) of the partial plates plates (5; 5a-5c; 9, 9a, 9b) are aligned, and wherein no conductors (22) are yet arranged in the grooves (16; 21) of the partial plates (5; 5a-5c; 9, 9a, 9b), in particular wherein butt joints (70) of the partial plates (5; 5a-5c; 9, 9a, 9b) are welded together; S2) into the grooves (16; 21) of the partial plate layer (8; 8a-8h, 43a-43h, 44a-44h, 47a-47h) a piece (73) of a superconducting conductor (22) is inserted, the length (LS) of which corresponds to the length (LN) of the groove (5; 5a-5c; 9, 9a, 9b) of the partial plate layer (8; 8a-8h, 43a-43h, 44a-44h, 47a-47h) along the local longitudinal direction (LLR); and that the magnet coil (1, 1a) is assembled from the partial plate layers (8; 8a-8h, 43a-43h, 44a-44h, 47a-47h) produced in this manner.
  20. Method for assembling a magnetic coil (1, 1a) according to one of the Claims 1 until 17 is constructed, wherein the magnetic coil (1, 1a) comprises at least one insertion section (ES, wES) and at least one further section (WS; WS1, WS2, WS3, ZS, AS), characterized in that first the further section (WS; WS1, WS2, WS3, ZS, AS) is provided, in particular wherein the partial plate layers (43a-43h, 44a-44h, 47a-47h) of the at least one further section (WS; WS1, WS2, WS3, ZS, AS) are stacked next to each other, and that afterwards the partial plate layers (8; 8a-8h) of the at least one insertion section (ES, wES) are added, wherein, with respect to the associated stack end side (OSE; SE1, SE2) according to a) or b) in the plate layer stack (4) the partial plate layers (8; 8a-8h) are located further inside are added in time before more outward partial plate layers (8; 8a-8h), thereby obtaining the complete magnetic coil (1, 1a).

Description

The invention relates to a magnetic coil especially stellarator coil or tokamak coil for a nuclear fusion plant, wherein a multitude of ring-shaped plate layers are present, in each of which several turns of a superconducting conductor are formed, wherein in each layer of plates a plurality of sub-plates are arranged in a ring-like sequence and in each layer of plates successive sub-plates are attached to one another, and wherein the plate layers form a ring-shaped plate layer stack and successive plate layers are in contact with each other, wherein each subplate forms several grooves into which the conductor is inserted, wherein the grooves of the sub-plate run along a local longitudinal direction, and the grooves of the sub-plate are arranged consecutively in a local transverse direction, where a local stacking direction is perpendicular to the local longitudinal direction and perpendicular to the local transverse direction, and wherein the grooves of successive sub-plates of a plate layer are aligned with each other, and in particular connect to each other. Such a magnetic coil became known through F. Schauer et al., “Extrapolation of the W7-X Magnet System to Reactor Size,” Contrib. Plasma Phys. 50, no. 8, 750-755 (2010 ). 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. 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 superconducting magnetic coils are arranged along the substantially toroidal plasma volume, each locally enclosing the toroidal plasma volume in a ring-like fashion. In the tokamak design, such as that used in the ITER fusion reactor, the individual magnetic coils (or tokamak coils) typically have a planar, two-dimensional geometry; however, tokamak coils with non-planar geometries are also known. A tokamak requires an electric current flowing in the plasma. In the stellarator design, the individual magnetic coils (or stellarator coils) each have a non-planar, 3D-shaped geometry; the structure is therefore somewhat more complex. A current flowing in the plasma is not required in a stellarator. A significant challenge in fusion reactors lies in assembling the necessary magnetic coils. A single magnetic coil in a fusion reactor can weigh up to 300 tons or even more, and often contains several thousand meters of superconducting wire. Due to the size of a fusion reactor compared to existing or under-construction fusion experiments, it is expected that the magnetic coils will have to be manufactured on-site. This makes manufacturing the magnetic coil complex and difficult. Repairs and maintenance of the magnetic coil are also complex and difficult. In the event of defects, for example in the conductor, the entire magnetic coil usually has to be replaced. Furthermore, the magnetic coils encircle the plasma vessel of the fusion reactor, with the coils being distributed around the entire circumference of the essentially toroidal plasma vessel. This makes access to the plasma vessel difficult, which in turn complicates assembly, repairs, and maintenance work on and inside the plasma vessel. F. Schauer et al. in Contrib. Plasma Phys., ibid Based on the design of the ITER tokamak coils, they discussed the potential design of stellarator coils, particularly for the HSR50a reactor, which belongs to the HELIAS type. The stellarator coil under discussion consists of stacked radial plates, each containing conductor windings. The paper notes that the coil housing, radial plates, and conductors would need to be bent. Furthermore, the radial plates could be manufactured in segments and then welded together at accessible edges. In A. van Arkel et al., “Unlocking maintenance - architecting STEP for maintenance and realizing remountable magnet joints”. For a STEP (Spherical Tokamak for Energy Production) fusion reactor, TF (toroidal field) coils with a rectangular ring-shaped structure are proposed, with a permanent joint at one corner and reassemblable joints at three corners. At the reassemblable joints, it is proposed that the two conductors to connect the ends edge to edge, with stacked ribbon ladders running parallel to each other at the two ladder ends. From the US 2023/0207171 A1 Detachable solder joints for coupling superconducting current paths have become known. For the D-shaped TF coils of a fusion reactor, it is proposed to incorporate detachable joint regions at two points between a straight section and a curved section, thus making the TF coil detachable. The two sections of the T