A controlled nuclear fusion system includes a vacuum chamber, an electrode cage shaped in a first closed-loop tube in the vacuum chamber, wherein the electrode cage comprises electrically conductive wires configured to confine ions and electrons in the electrode cage and a toroidal electromagnetic coil coiled around outside of the electrode cage and configured to produce a closed-loop magnetic flux in the electrode cage.

A bifilar winding system for the manufacture of poloidal field superconducting magnets for nuclear fusion includes two superconducting coil winding production lines which are symmetrically arranged, a dropping fixture, a rotary platform and a winding mold, and an automatic control system. Each of the two winding production lines includes a conductor unwinding device, a straightener, an ultrasonic cleaning machine, a sandblasting and cleaning machine, a bending machine, an inter-turn insulation taping machine. During the winding of a coil, a superconducting conductor is unwound by the conductor unwinding device under the control of the automatic control system, then straightened, ultrasonically cleaned, sandblasted and cleaned, and bent into a desired radius, then wrapped with multiple layers of insulating tape by the inter-turn insulation taping machine, and finally fixed, by the dropping fixture, precisely on the rotary platform at a correct position within a profile of the winding mold.

Neutron shielding. The neutron shielding comprises a plurality of absorption layers (201, 203), and at least one moderating layer (202). The plurality of absorption layers each comprise tungsten boride or tungsten carbide. The at least one moderating layer comprises a metal hydride. Each moderating layer is between at least two absorption layers.

A tokamak comprising a vacuum chamber, a toroidal field coil, and a solenoid. The solenoid is wound around the toroidal field coil within a central column region of the tokamak. The solenoid comprises an inner portion and two outer portions. The inner portion comprises windings extending axially for a first distance either side of the midpoint of the length of the solenoid. The outer portions, each comprise windings extending axially from an end of the inner portion. The inner portion has a number of turns per unit length which is greater than a number of turns per unit length of the outer portion.

A method of detecting pre-quench conditions in a superconducting magnet comprising an HTS field coil. The field coil comprises a plurality of turns comprising HTS material and metallic stabilizer; and conductive material connecting the turns such that current can be shared radially between turns via the conductive material. Strain is monitored for the HTS field coil and/or support structures of the HTS field coil. The monitored strain is compared to an expected strain during normal operation of the magnet. In response to the comparison, it is determined whether the field coil is in pre-quench conditions. A similar method is provided where the magnetic field of the HTS field coil is monitored to detect pre-quench conditions, instead of the strain.

A method of controlling a plasma in a nuclear fusion reactor. The nuclear fusion reactor comprises sensors and plasma control inputs. An initial control model is provided, relating readings of at least a subset of the sensors to control of the plasma control inputs. A control loop is performed, comprising: operating the plasma control inputs in dependence upon the sensors according to the control model; determining correlations between readings of each of the sensors, and/or between readings of the sensors and states of the plasma control inputs; and adjusting the control model based on the determined correlations.

A segment of a field coil, a toroidal field coil, and a method of manufacturing is provided. The segment of a field coil is for use in a superconducting electromagnet. The segment includes an assembly for carrying electrical current in a coil of a magnet. The assembly includes a pre-formed housing comprising a channel configured to retain high temperature superconductor (HTS) tape, the channel including at least one pre-formed curved section. The assembly further includes a plurality of layers of HTS tape fixed within the channel. Wherein the pre-formed curved section has a radius of curvature which is less than a total thickness of the layers of HTS tape in that section divided by twice a maximum permitted strain of the HTS tape.

A nuclear fusion reactor includes a chamber containing plasma and two or more devices which include superconducting electromagnetic coils. At least one of the two or more devices may be biased to a high voltage to provide thermal energy to ions in the magnetic confinement region. In some examples, the chamber and the two or more devices can be coaxial and toroid shaped. In some examples, the chamber can be spherical or cylindrical with the two or more devices being toroid or elongated toroid shaped and formed on opposite faces of a cuboid. The two or more devices may be disposed in the chamber to provide a high-beta magnetic confinement region for the plasma.

A nuclear fusion reactor includes a chamber containing plasma and two or more devices which include superconducting electromagnetic coils. At least one of the two or more devices may be biased to a high voltage to provide thermal energy to ions in the magnetic confinement region. In some examples, the chamber and the two or more devices can be coaxial and toroid shaped. In some examples, the chamber can be spherical or cylindrical with the two or more devices being toroid or elongated toroid shaped and formed on opposite faces of a cuboid. The two or more devices may be disposed in the chamber to provide a high-beta magnetic confinement region for the plasma.

A device comprising a high temperature superconductor, HTS, circuit; wherein the HTS circuit comprises: a quenchable section comprising HTS material and connected in series to other elements of the HTS circuit, the HTS material comprising a stack of HTS takes comprising at least one HTS tape; the device further comprising: a quenching system configured to quench the HTS material in the quenchable section; a quench protection system configured to detect temperature rises in the HTS circuit and, in response to detection of a temperature rise, cause the quenching system to quench the superconducting material in the quenchable section in order to dump stored magnetic energy from the HTS circuit into the quenchable section; wherein the HTS circuit is configured such that, when in use, the magnetic field on the or each HTS tape is substantially parallel to a a-b plane of the HTS tape, and the quenching system is configured to quench the HTS material by producing an additional magnetic field along the length of the or each HTS tape within the quenchable section, such that the additional magnetic field has a component perpendicular to the a-b plane of the HTS tape.