University of Malta researchers contribute toward world’s largest nuclear fusion reactor

Researchers at the University of Malta are contributing toward the construction of the International Thermonuclear Experimental Reactor (ITER), a €20 billion nuclear fusion reactor that aims to ‘ignite a star on Earth for energy’.

The reactor, known as a tokamak, is being constructed in Cadarache, France and it will be the world’s largest machine of its kind.

The European Union, the United States, Russia, China, India, Japan and South Korea have all joined forces to build this international experimental magnetic confinement machine to prove the feasibility of nuclear fusion as a large-scale and carbon-free source of energy based on the same principle that powers our Sun and stars. ITER is designed to produce net energy and maintain fusion reactions for long periods of time. It will be the first fusion device to test the integrated technologies, materials and physics regimes necessary to build power plants for the commercial production of fusion-based electricity.

By fusing deuterium and tritium (hydrogen isotopes) together and confining the plasma in the shape of a torus within a chamber with very strong superconducting magnets, ITER is designed to make the long-awaited transition from experimental studies of plasma physics to fullscale electricity-producing fusion power stations.

Through a collaboration set up with the Paul Scherrer Institute (PSI) in Villigen Switzerland, Karl Buhagiar, Dr Ing. Nicholas Sammut (Deputy Dean Faculty of ICT) & Dr Ing. Andrew Sammut (Dean Faculty of Engineering) worked on the measurement and characterisation of the ITER Toroidal Field (TF) coils which are core main elements of the machine.

The 18 superconducting Dshaped Toroidal Field (TF) coils each measure 13m by 8m and are cooled to -268°C in operating cryogenic conditions. At their design current of 68 000A, these superconducting coils carry about two thousand times the current found in a standard household wire. These currents generate a peak magnetic field of 11.8 T which is required to confine the plasma and control its shape and direction of movement inside the reactor chamber.

The UoM research team’s goal so far was to develop a magnetic measurement system for the determination of the TF coil current centre line (CCL). The determination of the CCL makes it possible to determine the TF coil’s magnetic field and hence how well the plasma can be confined.

Nuclear fusion reactions are very challenging to confine sustainably due to the extremely high temperatures involved. However, they release three times as much energy as current fission reactors and their fuels are abundant. They also produce 100 times less radioactive waste that is not long lived. The design of tokamaks is also such that it would be impossible to undergo large-scale runaway chain reactions. If this technology is harnessed, fusion reactors would be able to produce reliable electricity with virtually zero pollution. Hence fusion power has the potential to provide sufficient energy to satisfy mounting demand and to do so sustainably with a relatively small impact on the environment.