That’s important to find out because one day, the goal is to store all the radioactive fuel that’s used up and spit out by nuclear power plants in the US at a central, underground repository. There’s still a political struggle over where that repository will be, so right now, spent nuclear fuel doesn’t move much around the US. It mostly sits in storage at nuclear power plants or sometimes travels between power plants owned by the same company, according to the Nuclear Regulatory Commission (NRC), the government agency that oversees the nuclear industry.