US firm to accelerate plasma-free fusion at low temperatures with new funding

As the global energy need is rising, both public institutions and private companies have increased their efforts toward nuclear fusion.

The latest headline grabber in this sphere is Acceleron Fusion, a start-up working on muon-catalyzed fusion energy. The fusion energy firm has recently secured $24 million in funding to develop a revolutionary approach to clean energy production.

The funding follows a major technical milestone achieved by Acceleron in October.

The company successfully operated its experimental fusion reactor with highly compressed deuterium-tritium (DT) fuel for 28 continuous hours, following over 100 hours of testing with deuterium.

This achievement marks significant progress toward demonstrating the viability of muon-catalyzed fusion as a clean and abundant energy source.

Muon-catalyzed fusion offers a different approach

Acceleron Fusion is taking a different path from many other companies working on fusion energy.

They are not using the extremely high temperatures that are common in fusion experiments. Instead, Acceleron is developing a method that uses lower temperatures. This method uses special particles called muons.

Muons are similar to electrons, but they are about 200 times heavier. These muons are produced when protons and neutrons collide, creating particles called pions that then decay into muons.

Muons can be generated artificially by firing an ion beam from a particle accelerator into a target, typically made of carbon or metal.

When a beam of muons is directed at a highly compressed pellet of deuterium and tritium (common fusion fuels), the muons facilitate fusion reactions at temperatures far lower than those required in traditional fusion reactors. This is what Acceleron aims to tap.

Acceleron bypasses high-temperature requirements

Traditional fusion approaches, like magnetic confinement and inertial confinement, require immense heat to create plasma. This plasma must then be contained with powerful magnets or lasers, which are complex and energy-intensive.

Acceleron's technology bypasses these requirements by operating below 1,000°C. This "cooler" temperature operation potentially offers significant advantages in efficiency and safety.

“Traditional fusion machines require extreme temperatures of 100 million degrees Celsius,” explained the company in a press release. “Acceleron's technology uses muons—heavy subatomic particles—to achieve fusion reactions at temperatures below 1,000 degrees Celsius.”

However, muon-catalyzed fusion presents unique challenges. Particle accelerators, used to generate muons, consume a lot of energy.

“In the mid 1980s, several groups worldwide demonstrated more than 100 fusion reactions per muon, raising the possibility that the process could be used to generate energy,” highlighted the company.

“However, calculations done at the time concluded that it would take more energy to power the muon source than could be released by the fusion.”

To achieve net energy gain, each muon must catalyze many fusion reactions. Furthermore, muons are short-lived, decaying in just 2.2 microseconds. About 1% of the time, they stick to other particles produced during fusion, becoming unusable.

US-based firm aims to overcome technical challenges

“Acceleron is developing an intense, high-efficiency muon source to produce beams of muons using significantly less energy than current facilities, and a high-density fusion cell to allow each of these muons to catalyze larger numbers of fusion reactions,” asserted the press release.

To increase the number of fusion reactions per muon, Acceleron is compressing the fuel in a diamond anvil to pressures between 10,000 and 100,000 PSI. This is far beyond the pressures used in previous experiments.

Acceleron Fusion is not the only company working on nuclear fusion energy.

Several companies across the world have been testing several approaches, including magnetic confinement fusion, inertial confinement fusion, and even other variations of muon-catalyzed fusion.

However, all research activities on fusion energy are still in their nascent stages. According to experts, it might take many more years, if not decades, before fusion power becomes a reliable source of energy.