U.S. firms developing a new generation of small nuclear power plants to help cut carbon emissions have a big problem: Only one company sells the fuel they need, and it's Russian.

That's why the U.S. government is urgently looking to use some of its stockpile of weapons-grade uranium to help fuel the new advanced reactors and kick-start an industry it sees as crucial for countries to meet global net-zero emissions goals.

"Production of HALEU is a critical mission and all efforts to increase its production are being evaluated," a spokesperson for the U.S. Department of Energy (DOE) said, referring to high assay low enriched uranium.