Fusion is the process that powers the sun and stars; it works by combining light elements into heavier ones and releasing energy. If we recreate those processes on Earth, we can produce limitless electricity without producing greenhouse gases, which is what UKAEA strives to do. Fusion is not a chain reaction, which means we need to provide the fuel to keep it going and this makes it safer than nuclear fission reactors. To conduct fusion experiments on earth, we have to get a gas really hot, turning it into a ‘soup’ of charged particles called a plasma (the fourth state of matter after solid, liquid and gas).
On earth we use magnetic fields to confine that hot plasma in a device called a tokamak – a machine that essentially lets us make stars on earth. MAST Upgrade is UKAEA’s latest tokamak. It is an evolution of the original MAST machine (Maga Amp Spherical Tokamak), and 90% of the machine is new. A conventional tokamak (like the Joint European Torus, also known as JET) is the shape of the donut, while MAST Upgrade is spherical, more like an apple with its core removed, and is smaller and more efficient than conventional tokamaks. This design could be the key to future fusion power plants.
The MAST Upgrade project has three main aims:
1. to solve the exhaust problem. The heat escaping from the plasma is at a temperature like a spacecraft on re-entry to the atmosphere, and needs to be brought down to the temperature of a car engine. It is channelled through a new device called the Super X divertor to bring the temperature down.
2. to give crucial information to ITER, which will be the world’s largest fusion device and is currently under construction in the south of France.
3. to help design and build a future power plant in the UK called STEP.
The team are very excited to get MAST Upgrade up and running, and continue their important research need to make fusion energy a reality. They were delighted with our film and are currently using it to promote their work.