The fusion energy that produced a 120 per cent net energy gain took place in the federal Lawrence Livermore National Laboratory (LLNL) in California in the past two weeks, the newspaper said, citing three people with knowledge of the matter.
That would represent the first time that researchers have successfully produced more energy in a fusion reaction than was consumed during the process.
To achieve this, the scientists used a process called inertial confinement fusion, which involves bombarding a tiny pellet of hydrogen plasma with the world’s biggest laser.
Energy Department and LLNL spokespeople refused to comment or provide confirmation regarding the FT report, but said US Energy Secretary Jennifer Granholm would "announce a major scientific breakthrough" on Tuesday.
The Washington Post later reported two people familiar with the research confirmed the development, with a senior fusion scientist telling the newspaper, "to most of us,...