Tuesday’s announcement by the U.S. Department of Energy that researchers at Lawrence Livermore Laboratory had sparked a fusion reaction that released more energy than the amount used to ignite it drew wows from scientists, government officials, and reporters. But the milestone, while significant, will have little impact on the work being done by Commonwealth Fusion Systems at Devens.
The Livermore result was, however, a first. Never before, in more than seven decades of research, has a fusion reaction released more energy than the amount used to ignite it. “It’s a moment to remember,” declared science reporter Miles O’Brien on the PBS NewsHour. “A landmark achievement,” said U.S. Secretary of Energy Jennifer M. Granholm, announcing the results in Washington, D.C.
The result was produced by focusing 192 beams of laser light generated by the world’s largest laser on a pellet the size of an eraser, causing it to implode and forcing the deuterium and tritium nuclei inside to fuse. The explosion lasted trillionths of a second, but released an amount of energy equivalent to about three sticks of dynamite, according to Science Magazine reporter Daniel Clery—2.05 megajoules of energy in; 3.15 MJ out. Less noted, however, were the more than 300 MJ of electricity required to power Livermore’s monster laser.
The approach to commercial fusion being pursued by scientists and engineers at Commonwealth Fusion, an MIT spinoff, is entirely different. Instead of high energy beams of laser light, the experimental SPARC reactor being constructed at Devens will use powerful magnetic fields to force hydrogen atoms to fuse in a furnace-like device known as a tokamak. Many in the world of fusion labs and private startup companies believe this technique is the one most likely to succeed and lead to the commercialization of fusion as an energy source, though not for several decades.
Nevertheless, in a statement released to the press, CFS CEO and co-founder Bob Mumgaard was enthusiastic. “This is a great moment for fusion,” he said. “These exciting results are the culmination of years of work, demonstrating that fusion science is worth the investment. It’s an important validator for CFS and the fusion industry on the path toward commercial fusion energy.”
Last week construction workers at the CFS Devens site reached a milestone of their own, capping off the building that will house the company’s multistory SPARC device, scheduled to be operational in 2025. If the device succeeds, the company hopes to start work on a commercial plant by the end of this decade.
