As global energy rises, both public institutions and private companies have increased their efforts toward nuclear fusion. Acceleron Fusion is a start-up working on muon-catalyzed fusion energy. The fusion energy firm has recently secured twenty-four million dollars in funding to develop a revolutionary approach to clean energy production. The funding follows a major technical milestone that was achieved by Acceleron in October.
The company successfully operated its experimental fusion reactor with highly compressed deuterium-tritium (DT) fuel for twenty-eight continuous hours, following over one hundred hours of testing with deuterium. This achievement signals significant progress toward demonstrating the viability of muon-catalyzed fusion as a clean and abundant energy source.
Acceleron Fusion is working on a radically different reactor design from many other companies working on fusion energy. The company is not using the extremely high temperatures that are common in fusion experiments. Instead, Acceleron is working on a method that uses much lower temperatures. Their new method utilizes particles called muons.
Muons are similar to electrons, but they are about two hundred times heavier. They are produced when protons and neutrons collide. This creates particles called pions which then decay into muons. Muons can be generated artificially by firing an ion beam from a particle accelerator into a target which is typically made of carbon or some metal.
When a beam of muons is directed at a highly compressed pellet of deuterium and tritium, the muons facilitate fusion reactions at temperatures much lower than those required in traditional fusion reactors.
Traditional fusion approaches, such as magnetic confinement and inertial confinement, require enormous heat to create plasma. This plasma must then be contained and compressed with powerful magnets or lasers, which are complex and energy-intensive.
Acceleron’s technology bypasses these requirements by operating below one thousand eight hundred and thirty-two degrees Fahrenheit. Operating at this cooler temperature potentially offers significant advantages in efficiency and safety.
According to a company in a press release, “Traditional fusion machines require extreme temperatures of one hundred and eighty million degrees Fahrenheit. Acceleron’s technology uses muons to achieve fusion reactions at temperatures below two thousand degrees Fahrenheit.”
However, muon-catalyzed fusion presents a number of unique challenges. Particle accelerators which are used to generate muons, consume a lot of energy.
The company added that “In the mid-1980s, several groups worldwide demonstrated more than one hundred fusion reactions per muon, raising the possibility that the process could be used to generate energy. 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.”
In order to achieve net energy gain, each muon must catalyze many fusion reactions. Furthermore, muons are short-lived, and they decay in just two and two tenths microseconds. About one percent of the time, they stick to other particles produced during fusion and become unusable.
The press release added that “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.”
To increase the number of fusion reactions per muon, Acceleron compresses the fuel in a diamond anvil to pressures between ten thousand and one hundred thousand pounds per square inch. This is far beyond the pressures that they used in previous experiments.
Acceleron Fusion is not the only company working on nuclear fusion energy research. A number of other companies across the world have been testing several different approaches, including magnetic confinement fusion, inertial confinement fusion, and even other variations of muon-catalyzed fusion. However, according to experts, it might take many more years before fusion power becomes a reliable source of energy.