Scientists at the UK Atomic Energy Authority (UKAEA) have tested a world-first concept that could address one of the biggest hurdles in developing fusion energy.

Initial results from UKAEA’s new ‘MAST Upgrade’ experiment have demonstrated the effectiveness of an innovative exhaust system designed to make compact fusion power plants commercially viable.

The government department said that with no greenhouse gas emissions and abundant fuels, fusion can be a safe and sustainable part of the world’s future energy supply.

Fusion energy is based on the same principle by which stars create heat and light. Using a machine called a ‘tokamak,’ a fusion power station will heat a gas, or ‘plasma’, enabling types of hydrogen fuel to fuse together to release energy that can generate electricity.

A key challenge in getting tokamaks on the electricity grid is removing excess heat produced during fusion reactions.

Without an exhaust system that can handle this intense heat, materials will have to be regularly replaced – significantly affecting the amount of time a power plant could operate for.

The new system, known as a ‘Super-X divertor’, would allow components in future commercial tokamaks to last for much longer; greatly increasing the power plant’s availability, improving its economic viability and reducing the cost of fusion electricity.

Tests at MAST Upgrade, which began operating in October 2020, have shown at least a tenfold reduction in the heat on materials with the Super-X system.

The government said that this is a “game-changer” for achieving fusion power plants that can deliver affordable, efficient electricity.

UKAEA is planning to build a prototype fusion power plant – known as STEP – by the early 2040s, using a compact machine called the ‘spherical tokamak’.

MAST Upgrade is funded by the UK Government’s Department for Business, Energy & Industrial Strategy, the Engineering & Physical Sciences Research Council (EPSRC) and the EUROfusion consortium.

“These are fantastic results. They are the moment our team at UKAEA has been working towards for almost a decade,” said Dr Andrew Kirk, UKAEA’s lead scientist at MAST Upgrade. “We built MAST Upgrade to solve the exhaust problem for compact fusion power plants, and the signs are that we’ve succeeded.

Kirk added: “Super-X reduces the heat on the exhaust system from a blowtorch level down to more like you’d find in a car engine. This could mean it would only have to be replaced once during the lifetime of a power plant.”

Amanda Solloway, UK science minister, said that the successful test represented an “incredible breakthrough” for fusion energy.

“Just seven months since MAST Upgrade was powered up, it may already have found a solution to one of fusion’s greatest challenges,” said Solloway. “Innovative projects like this one are crucial to cementing our status as a science superpower, and I am excited to see how it develops.”

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