The New Orleans-based 5th U.S. Circuit Court of Appeals found that the NRC lacked authority to issue the license based on a law called the Atomic Energy Act of 1954. Biden's administration appealed the ruling at the Supreme Court and Trump's administration continued the appeal.
Biden's Solicitor General Elizabeth Prelogar argued in a December brief that the 5th Circuit ruling would "entirely gut" the Atomic Energy Act because nuclear power plants cannot operate without creating spent fuel that must be stored somewhere.
The Trump administration's acting Solicitor General Sarah Harris told the justices in February that the 5th Circuit decision could "deprive the commission of authority to license the private storage of spent nuclear fuel in any location" and "grind the operations of nuclear reactors to a halt."