US fusion startup Inertia Enterprises says it has cut the time needed to manufacture its fuel pellets from several days to just minutes, addressing one of ten technical barriers it must clear before building a commercial power plant. The breakthrough matters because the company's $450 million in funding rests on its ability to commercialise fusion technology developed at California's National Ignition Facility (NIF), where pellet production is a slow, costly, near-artisanal process better suited to producing scientific prototypes than mass-market fuel.

Each pellet consists of a spherical diamond shell containing a precisely frozen layer of deuterium and tritium around a gaseous core, and must be almost perfectly round to trigger fusion when compressed by laser-generated X-rays inside a gold casing. Inertia says it can now grow the required crystal layer in about 30 minutes rather than up to a week, with a complete pellet made in two to three hours, partly because its planned laser will be four times more powerful than NIF's, giving it more tolerance for imperfections. The faster process also reduces how much tritium the company needs to store at once, which matters given the isotope is radioactive and costs around $30,000 per gram, with only about 25 kilograms available worldwide.