Granholm stressed that the breakthrough strengthens US national security and is "one significant step closer to the possibility of zero-carbon abundant fusion energy powering our society."
She said fusion energy can be used to produce clean electricity for transportation fuels to power heavy industry and much more in a clean energy economy.
The secretary said private sector investment and fusion research are already booming, reaching $3 billion last year alone and added that it meets President Joe Biden's goal to achieve commercial fusion within a decade.
Granholm noted that the Energy Department made a $50 million investment in September for a public-private partnership to start working toward fusion-pilot plant designs.
Fusion, which occurs when two nuclei combine to form a new nucleus, offers a potential long-term energy source that uses abundant fuel supplies and does not produce greenhouse gases or long-lived radioactive waste, according to the Energy Department.
Creating conditions for fusion on Earth involves generating and sustaining plasmas which are hot gases that electrons are freed from atomic nuclei, it added.