FILE - In this May 11, 2015 file photo, nuclear waste is stored in underground containers at the Idaho National Laboratory near Idaho Falls, Idaho. Federal officials say testing of a small-scale version of a key component of this eastern Idaho radioactive waste treatment facility that has so far failed to operate is making progress at finding a solution. The U.S. Department of Energy said Wednesday, June 28, 2017, that results from testing at Hazen Research near Denver, Colo., will be used during planned tests at the Idaho facility later this year. (AP Photo/Keith Ridler, File)
FILE - In this May 11, 2015, file photo, nuclear waste is stored in underground containers at the Idaho National Laboratory near Idaho Falls, Idaho. Federal officials are requesting a 20-year extension involving the storage at an Idaho facility of reactor core debris from the partial meltdown at the Three Mile Island nuclear power plant. The U.S. Department of Energy in a document made public on Friday, June 9, is asking the Nuclear Regulatory Commission to renew a license for the storage to 2039 at its square mile site in eastern Idaho that includes the Idaho National Laboratory. (AP Photo/Keith Ridler, File)