U.S. government scientists have achieved net energy gain in a fusion reaction for the second time since December last year, the Financial Times reported on Sunday.

Researchers at the federal Lawrence Livermore National Laboratory in California repeated the breakthrough in an experiment on July 30 that produced a higher energy output than in December, the newspaper said, citing people with knowledge of the results.

The same lab achieved a net energy gain in a fusion experiment using lasers on Dec. 5, 2022. The scientists focused a laser on a target of fuel to fuse two light atoms into a denser one, releasing the energy.

The laboratory confirmed to the FT that energy gain had been achieved again at its laser facility, adding that analysis of the results was underway.

The Lawrence Livermore National Lab and the U.S. Energy Department did not immediately respond to Reuters' request for comment.

(Reporting by Lavanya Ahire in Bengaluru; Editing by Leslie Adler)