Research & Development

Nuclear Fusion / First Plasma Achieved At UK’s £55m ‘Mast’ Tokamak

By David Dalton
29 October 2020

First Plasma Achieved At UK’s £55m ‘Mast’ Tokamak
The Mast Upgrade machine at Culham near Oxford.. Courtesy UKAEA.
The UK Atomic Energy Authority’s £55m Mast (Mega Amp Spherical Tokamak ) Upgrade machine has achieved first plasma – where all the essential components work together simultaneously.

The UKAEA said the device, which has taken seven years to build at the Culham Centre for Fusion Energy near Oxford, will take the UK closer to delivering fusion energy and will be a vital testing facility for delivering the Step fusion power plant. Step (Spherical Tokamak for Energy Production) is due for completion by 2040.

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 requires a careful balancing act of controlling extreme heat, gas and powerful magnetic fields, amongst other complex systems.

One of the biggest challenges in fusion research has been to extract the amount of excess heat from the plasma. UKAEA scientists now plan to test a new exhaust system, called the Super-X divertor, at the Mast facility.

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, the UKAEA said.

The UKAEA is designing Step in an initial £220m programme funded by the UK government. Mast will also aid preparations for the Iter fusion plant – the world’s largest science megaproject, now being built in the South of France, which intends to demonstrate fusion power on an industrial scale.

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