First plasma for British fusion reactor


For the first time, after a seven-year build, the UK Atomic Energy Authority’s Mega Amp Spherical Tokamak (Mast) Upgrade, has achieved first plasma. All the essential components work together simultaneously.

Fusion energy offers the potential of an abundant, inherently safe low-carbon electricity supply. It involves fusing hydrogen particles in a hot gas known as a ‘plasma’ to unlock large amounts of energy. Operating fusion technologies however requires a careful balancing act of controlling extreme heat, gas and powerful magnetic fields, amongst other complex systems.

Reduction in heat arriving

One of the biggest challenges in fusion research has been to extract the amount of excess heat from the plasma. Scientists from UK Atomic Energy Authority (UKAEA) now plan to test a new exhaust system called the ‘Super-X divertor’ at Mast Upgrade. This system is designed to channel plasma out of the machine at temperatures low enough for its materials to withstand. Meaning that components can last much longer.

The approximate tenfold reduction in heat arriving at the internal surfaces of the machine has the potential to be a game-changer for the long-term viability of future fusion power stations.

Next step

Mast Upgrade will be the forerunner of the UK’s prototype fusion power plant, Spherical Tokamak for Energy Production (Step). Which is due for completion by 2040. While Mast Upgrade cost ‘only’ £55 million, the new reactor is engineered in an £220 million programme. Funded by the UK Government.

The design will be based on Mast Upgrade’s ‘spherical tokamak’ fusion concept. The spherical tokamak could offer a route to a compact fusion power plant. The success of Mast Upgrade is another step along the way to designing future fusion power facilities, which could have an important role as part of a future portfolio of low-carbon energy.


Mast Upgrade will also aid preparations for Iter. The world’s largest science megaproject, now being built in the South of France. Which intends to demonstrate fusion power on an industrial scale.

Wim Raaijen
I am a creative publisher, editor in chief, writer, vlogger and moderator with a journalistic and philosophic based view. Trying to re-invent the concept of publishing, based on platforms and partners, instead of separated media and advertisements. I am interested in industrial subjects like transition, sustainability, safety, energy efficiency, innovation and responsibility.

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