Fusion power has experienced a renaissance in recent years, with billions of dollars in private investment flowing into the field. Acceleron Fusionis the latest startup to take a swing at this challenging nuclear-energy technology, banking on a novel approach that uses beams of heavy subatomic particles called muons to achieve fusion at much lower temperatures.
The company, based in Cambridge, Mass., is designing a plant that will rely on muon-catalyzed fusion, a phenomenon first observed in the 1950s. Its reactor will work by firing a beam of muons at a pellet of nuclear fuel kept under extremely high pressure. Using this approach, Acceleron’s plant could operate below 1,000 °C—not exactly “cold” fusion, but not nearly as hot as other strategies such as magnetic confinement or inertial confinement.
These other fusion approaches require temperatures in the millions of degrees to heat fuel until it becomes a plasma. The plasma must be contained using extremely powerful magnets or lasers, which are complex and power hungry, so being able to do without them is a significant benefit for Acceleron’s lukewarm approach to fusion. “It adds a great amount of technical simplicity and engineering flexibility,” says Ara Knaian, electrical engineer and CEO and cofounder of Acceleron.
Today, Acceleron announced it has closed a US $24 million funding round to help develop prototypes of key reactor components and has now completed 100 hoursof continuous fusion at its test facility at the Paul Scherrer Institute in Villigen, Switzerland. The experiments are aimed at gathering data rather than producing useful amounts of energy.
Muon-Catalyzed Fusion Power
The muons at the heart of Acceleron’s approach are from the same family of subatomic particles as electrons, but roughly 200 times their mass. They are created when protons and neutrons collide, which generates particles known as pions that then decay into muons. In nature, they occur when cosmic rays hit the upper atmosphere of Earth, but they can also be generated artificially by firing an ion beam from a particle accelerator into a target, typically made of carbon or metal.
Accleron’s high density fusion cell contains a millimeter-scale sample of highly compressed deuterium-tritium that will undergo muon-catalyzed fusion. Ara Knaian/Acceleron Fusion
The resulting muons can help kick-start a fusion reaction by being directed at a mixture of the hydrogen isotopes deuterium and tritium—popular fuel for fusion reactors. Muons displace electrons in the hydrogen atoms, resulting in hydrogen molecules made up of a deuterium and a tritium atom chemically bonded by a muon rather than an electron. Because muons are much heavier, the length of this bond is reduced to roughly 0.5 percent of the original. This brings the two atoms close enough that the strong nuclear force—the force that holds nuclei together—takes over and pulls the atoms together until they fuse, releasing massive amounts of…
Read full article: Fusion Power Breakthrough: Acceleron Fusion’s Muon Reactor
The post “Fusion Power Breakthrough: Acceleron Fusion’s Muon Reactor” by Edd Gent was published on 12/03/2024 by spectrum.ieee.org