Young fusion startup Acceleron Fusion raises an impressive $15 million.

The emerging company Acceleron Fusion recently announced that it has raised $15 million from a targeted funding round of $23.7 million. This information was revealed in a filing with the US Securities and Exchange Commission (SEC). The fusion sector is currently experiencing a significant influx of investment, driven by a groundbreaking experiment at the National Ignition Facility two years ago, which demonstrated that a controlled fusion reaction can generate more energy than is required for ignition. The company that first builds a power plant capable of supplying electricity to the grid on a large scale will claim a significant share of the global energy market, valued at several trillion dollars. Particularly, technology companies have shown a growing interest in fusion and nuclear-based startups to meet their substantial energy requirements in an environmentally friendly manner. Acceleron did not initially respond to inquiries. Unlike other startups attempting to mimic the extremely hot and high-pressure conditions inside a star, Acceleron is pursuing a different approach. The company uses subatomic particles called muons to reduce the necessary heat and pressure for fusion reactions. Typically, atoms resist fusion because their orbiting electrons repel other atoms. To overcome this, most fusion approaches heat the atoms significantly to release their electrons. Without electrons, atomic nuclei can fuse together, releasing enormous amounts of energy, akin to what happens in a star. In muon-catalyzed fusion, however, muons are added to the mixture. Muons are subatomic particles with similar properties to electrons but possess 207 times the mass. They replace electrons in some atoms, causing these atoms’ electrons to orbit closer to the nucleus and lowering the fusion threshold. This method enables fusion at room temperature and pressure, occasionally referred to as cold fusion. Despite promising laboratory conditions, the energy required for muon production currently exceeds the output from fusion reactions. There are challenges, though: muons have a lifespan of only 2.2 microseconds and conduct about 100 fusion reactions before decaying. Additionally, approximately 0.8% of the muons become bound to other subatomic particles, reducing their efficiency. Acceleron, based in Cambridge, Massachusetts, and originally a spin-off from NK Labs, hopes to reduce the muon binding rate and thus increase fusion yields by increasing the pressure and possibly the temperature of the hydrogen isotope mixture. In 2020, NK Labs received a three-year ARPA-E grant of $2 million to investigate whether higher pressure could improve the prospects for muon-catalyzed fusion. These investigations, not yet fully disclosed, have apparently piqued the interest of investors.