American businesses are paying around $1 billion per year to Russia’s state-owned nuclear program, The New York Times reported Wednesday. Why? U.S. nuclear power companies rely on the cheap uranium made by Russia to fuel more than half of America’s emissions-free energy. As the U.S. and its allies work to cut economic ties with Moscow amid the war in Ukraine, this nuclear energy money is one of the most significant ties left. While the U.S. and Europe massively cut back on the amount of fossil fuel being purchased from Russia, finding an alternative to its enriched uranium supply isn’t so easy. Russia is the world’s cheapest producer of enriched uranium—cutting it out could take years, and a lot more funding from the U.S. government than is currently allocated.