TerraPower, the advanced nuclear company backed by Bill Gates, announced last week that the start date for its Natrium reactor has been pushed back. As Russia is currently the only commercial source of the high-assay low- enriched uranium (HALEU) the plant requires, the company faces a lack of fuel availability. TerraPower originally planned to use Russian fuel to get its demonstration reactor up and running by 2028, but Russia’s invasion of Ukraine has dashed those plans.