Building a working nuclear fusion reactor has proven to be a daunting challenge even for multiple wealthy nations, as we've seen with the much-delayed ITER project. However, a private start-up called Helion thinks it can build one and start supplying energy by 2028 by taking a different approach than other reactors.

Fusion energy company Helion has secured a substantial $425m in series F funding, aimed at accelerating the commercialisation of its fusion technology. The funding round saw contributions from a mix of new and existing investors.

They were joined by several existing backers including Sam Altman, who invested $375 million in Helion four years ago. The company is now valued at $5.245 billion. Nuclear reactors generate energy through a process called fission,