Abstract: 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.

Abstract: 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.

Abstract: A tokamak fusion reactor. The tokamak fusion reactor comprises a toroidal plasma chamber and a plasma confinement system arranged to generate a magnetic field for confining a plasma in the plasma chamber. The plasma confinement system comprises toroidal field magnets, which generate a magnetic field, BT0, in the centre of the plasma. The toroidal field magnets are configured such that, in use, the magnetic field, on conductor of the toroidal field magnets is at least 20 Tesla. The plasma confinement system is configured such that, in use, the plasma has: an aspect ratio, A, of 2 or less; an elongation, K, of at least 2; a major radius R0 of 3.5 meters or less; a normalised beta of at least 3; an engineering safety factor, qeng, of at least 2.0; wherein the engineering safety factor qeng is defined as: geng=5 BT0R0K/A2IP where Ip is the plasma current; a ratio of the fusion gain, Qfus to the fusion power, Pfus, greater than 0.03 MW?1 at fusion power, Pfus, less than 500 MW.

Abstract: 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.

Abstract: A method of operating a nuclear fusion device. The nuclear fusion device comprises a toroidal plasma chamber and has poloidal field coils configured to form a plasma within the plasma chamber by one of merging compression and double null merging. A varying current is provided to the poloidal field coils. The varying current comprises a plurality of pulses. Each pulse comprises a plasma formation period having a rate of change of current which is opposite in sign to the current; and a merging period following the plasma formation period and having a current sufficiently low in magnitude as to allow plasmas within the chamber to merge into a single plasma. The current during the plasma formation period is varied such that the energy density of the single plasma immediately after merging is sufficient for fusion to occur.

Abstract: There is disclosed a toroidal field coil for use in a spherical tokamak. The toroidal field coil comprises a central column and a plurality of return limbs. The central column comprises a plurality of exfoliated HTS tapes, and the return limbs comprise a plurality of substrated HTS tapes. Each exfoliated HTS tape comprises a ReBCO layer bonded to respective metal interface layers on each side of the ReBCO layer, each metal interface layer being bonded to a metal stabiliser layer. Each substrated HTS tape comprises a ReBCO layer bonded on one side to a metal interface layer and on the other side to an oxide buffer stack, the metal interface layer being bonded to a metal stabiliser layer and the oxide buffer stack being bonded to a substrate.

Abstract: A method of operating a nuclear fusion device. The nuclear fusion device comprises a toroidal plasma chamber and has poloidal field coils configured to form a plasma within the plasma chamber by one of merging compression and double null merging. A varying current is provided to the poloidal field coils. The varying current comprises a plurality of pulses. Each pulse comprises a plasma formation period having a rate of change of current which is opposite in sign to the current; and a merging period following the plasma formation period and having a current sufficiently low in magnitude as to allow plasmas within the chamber to merge into a single plasma. The current during the plasma formation period is varied such that the energy density of the single plasma immediately after merging is sufficient for fusion to occur.

Abstract: There is disclosed a toroidal field coil for use in a spherical tokamak. The toroidal field coil comprises a central column and a plurality of return limbs. The central column comprises a plurality of exfoliated HTS tapes, and the return limbs comprise a plurality of substrated HTS tapes. Each exfoliated HTS tape comprises a ReBCO layer bonded to respective metal interface layers on each side of the ReBCO layer, each metal interface layer being bonded to a metal stabiliser layer. Each substrated HTS tape comprises a ReBCO layer bonded on one side to a metal interface layer and on the other side to an oxide buffer stack, the metal interface layer being bonded to a metal stabiliser layer and the oxide buffer stack being bonded to a substrate.

Abstract: There is described neutron shielding for a nuclear fusion reactor. The neutron shielding includes a cemented carbide or boride comprising a binder and an aggregate, the aggregate comprising particles of a carbide or boride compound.

Abstract: 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.

Abstract: There is described neutron shielding for a nuclear fusion reactor. The neutron shielding includes a cemented carbide or boride comprising a binder and an aggregate, the aggregate comprising particles of a carbide or boride compound.

Abstract: A toroidal field coil for generating a toroidal magnetic field in a nuclear fusion reactor includes a toroidal plasma chamber having a central column. The toroidal field coil has a plurality of windings configured to pass through the central column and around the outside of the plasma chamber. Each winding includes a cable having a plurality of stacked high temperature superconductor (HTS) tapes, each HTS tape including one or more layers of a high temperature superconductor material. With the toroidal field coil in place in the reactor, a face of each HTS tape is substantially perpendicular to a direction of maximal neutron flux during reactor operation as the cable passes through the center column.

Abstract: A toroidal field coil for generating a toroidal magnetic field in a nuclear fusion reactor comprising a toroidal plasma chamber having a central column. The toroidal field coil comprises a portion passing through the central column. The portion passing through the central chamber comprises: ?a low temperature superconductor, LTS, layer (21) formed from LTS; ?a high temperature superconductor, HTS, layer (22) formed from HTS and located radially outward of the LTS layer. ?a non-superconducting conductive layer (23) formed from electrically conducting, non-superconducting material and located radially outward of the HTS and LTS layers.

Abstract: An efficient compact nuclear fusion reactor for use as a neutron source or energy source is described. The reactor comprises a toroidal plasma chamber and a plasma confinement system arranged to generate a magnetic field for confining a plasma in the chamber. The plasma confinement system is configured so that a major radius of the confined plasma is 1.5 m or less. The reactor is constructed using high temperature superconducting toroidal magnets, which may be operated at low temperature (77K or lower) to provide enhanced performance. The toroidal magnetic field can be increased to 5 T or more giving significant increases in fusion output, so that neutron output is very efficient and the reactor can produce a net output of energy.

Abstract: A toroidal field coil for generating a toroidal magnetic field in a nuclear fusion reactor comprising a toroidal plasma chamber having a central column. The toroidal field coil comprises a portion passing through the central column. The portion passing through the central chamber comprises: a low temperature superconductor, LTS, layer (21) formed from LTS; a high temperature superconductor, HTS, layer (22) formed from HTS and located radially outward of the LTS layer. a non-superconducting conductive layer (23) formed from electrically conducting, non-superconducting material and located radially outward of the HTS and LTS layers.

Abstract: There is described neutron shielding for a nuclear fusion reactor. The neutron shielding includes a cemented carbide or boride comprising a binder and an aggregate, the aggregate comprising particles of a carbide or boride compound.

Abstract: An efficient compact nuclear fusion reactor for use as a neutron source or energy source includes a toroidal plasma chamber and a plasma confinement system arranged to generate a magnetic field for confining a plasma in the chamber, where the plasma confinement system is configured so that a major radius of the confined plasma is 1.5 m or less and the toroidal magnetic field is operated 5 T or less and the plasma current is 5 MA or less, yet a-particles generated are confined in the plasma.

Abstract: Disclosed herein is a toroidal field coil for generating a toroidal magnetic field in a nuclear fusion reactor comprising toroidal plasma chamber having a central column, the toroidal field coil comprising a plurality of windings passing through the central column and around the outside of the plasma chamber. Each winding includes a cable comprising a plurality of stacked HTS tapes, each HTS tape including one or more layers of a high temperature superconductor material.

Abstract: An efficient compact nuclear fusion reactor for use as a neutron source or energy source is described. The reactor comprises a toroidal plasma chamber and a plasma confinement system arranged to generate a magnetic field for confining a plasma in the chamber. The plasma confinement system is configured so that a major radius of the confined plasma is 1.5 m or less. The reactor is constructed using high temperature superconducting toroidal magnets, which may be operated at low temperature (77K or lower) to provide enhanced performance. The toroidal magnetic field can be increased to 5 T or more giving significant increases in fusion output, so that neutron output is very efficient and the reactor can produce a net output of energy.