Boost to research into carbon-free 'energy source of the future'

The Culham Centre for Fusion Energy (CCFE) in Oxfordshire is now equipped with the world’s most advanced system for recording fusion plasma temperatures and density profiles thanks to a £2 million upgrade of MAST.

Fusion is the process that heats the sun and all other stars, whereby atomic nuclei collide together and release energy. Nuclear energy is obtained from the nucleus of atoms, by breaking the bonds that hold nucleus particles together, known as nuclear fission. In nuclear fusion two light atomic nuclei fuse together to form a heavier nucleus and in doing so, release a large amount of energy.

To derive energy from fusion, gas from a combination of types of hydrogen – deuterium and tritium – is heated to very high temperatures (100 million degrees Celsius), through a ‘magnetic confinement’ process, which controls the hot gas (plasma) with strong magnets in a ‘tokamak’ device, a doughnut-shaped chamber used in fusion research.
The Joint European Torus (JET), located at CCFE, is the largest and most powerful tokamak currently operating.

CCFE says nuclear fusion could play a key role in the energy market of the future, with the potential to produce at least 20 per cent of the world’s electricity by 2100.

The advantages of fusion, according to the scientists working on it, are that the process produces no greenhouse gases; produces no long-lived radioactive waste (all waste will be recyclable within 100 years); has inherent safety features; and offers almost unlimited fuel supplies.

The CCFE says that on current estimates, the cost of fusion-generated electricity is predicted to be broadly comparable to that obtained from fission, renewables and fossil fuels.

The £2 million upgrade to the MAST tokamak, will give UK physicists unprecedented insight into the behaviour of fusion plasmas. The upgrade has increased the number of measurements that can be made during a MAST plasma pulse by doubling the amount of lasers used to eight. This allows over 150 separate time points to be captured during the lifetime of plasma, from 130 different locations. A triggering device can synchronise lasers to the exact time of specific ‘events' during the pulse, such as the formation of the plasma or the injection of fuel pellets.

Commenting on the upgrade CCFE project leader Dr Mike Walsh said: “We expect the system to throw up new physics and allow us to observe effects we have never been able to see in plasmas before. We can also get a more accurate picture of occurrences we already know about; for example, the formation of ‘magnetic islands' that affect confinement of the plasma and reduce fusion energy output.”

The upgrade has been part-funded (£400,000) by the University of York and the Northern Way collaboration of Regional Development Agencies. CCFE says that diagnostic is already providing data exceeding its design specifications.

Experiments will run on MAST direct from York, using a new remote control room recently installed at the university.