The Department of Energy already buries some nuclear waste in salt beds, and some officials think the plan should be expanded so more radioactive waste can also be deposited there. At the Waste Isolation Pilot Plant in the desert of Carlsbad, New Mexico, the waste is deposited half a mile below ground in rooms as long as football fields carved out of the salt beds. The salt then acts as a natural sealant, the New York Times reports: Tiny amounts of water inside the salt slowly move toward the heat radiating from the waste, closing in on it at a rate of six inches a year. Experts say the waste will remain sealed for millions of years.
"It's eternity," says one Energy Department tour guide. And "the salt is completely unaffected by any nuclear waste you could imagine, period," says a geologist. Officials think the WIPP site could act as a replacement for the stalled Yucca Mountain repository, which was meant to store waste from spent nuclear fuel. That waste is more radioactive than the plutonium waste currently allowed at WIPP, but experts say with more testing and analysis, the more radioactive waste could potentially also be deposited at WIPP. Many local leaders are eager to expand WIPP, but some state officials oppose the plan, which would need to be approved by Congress before it could move forward. (Read more nuclear waste stories.)