A key component of the US energy program is to provide for the safe and permanent isolation of spent nuclear fuel and long-lived radioactive waste produced through programs related to national defense and the generation of electric power by nuclear utilities. To meet this challenge, the US Department of Energy (DOE) has developed a multi-faceted approach to the geologic disposal of long-lived nuclear wastes. Two sites are being developed or studied as current or potential deep geologic repositories for long lived radioactive wastes, the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico and Yucca Mountain, Nevada.