The U.S. Department of Energy said on Dec. 11 it would announce a “major scientific breakthrough” this week, after media reported a federal laboratory had recently achieved a major milestone in nuclear fusion research. The Financial Times reported Dec. 11 that scientists in the California-based Lawrence Livermore National Laboratory (LLNL) had achieved a “net energy gain” from an experimental fusion reactor.
The LLNF confirmed that a successful experiment had recently taken place at its National Ignition Facility (NIF) but said analysis of the results was ongoing. The NIF uses a process called “inertial confinement” fusion that involves bombarding a tiny pellet of hydrogen plasma with the world’s biggest laser.
The key to the Livermore work for the past two years is their surrounding the fuel pellet with an electrical coil producing a magnetic field which keeps the plasma compressed even as it is exploding from the lasers’ initial implosion of it. A hybrid of inertial confinement and magnetic confinement fusion was projected by the Fusion Energy Foundation and collaborators already in the late 1970s. With smaller and less expensive devices than Livermore’s laser array, the approach of a plasma “pinch” is now being used in many experiments internationally, making an international crash program for fusion possible if only the will existed in governments to do it.
The experiment produced about 2.5 megajoules of energy, a net energy gain of about 120% of the 2.1 megajoules of energy in the lasers. While the data are still being analyzed, two of the people with knowledge of the results said the energy output had been greater than expected, which had damaged some diagnostic equipment, complicating the analysis. The breakthrough was already being widely discussed by scientists, the people added.