CARLSBAD, N.M. — Half a mile beneath the desert surface, in thick salt beds left behind by seas that dried up hundreds of millions of years ago, the Department of Energy is carving out rooms as long as football fields and cramming them floor to ceiling with barrels and boxes of nuclear waste.
The salt beds, which have the consistency of crumbly rock so far down in the earth, are what the federal government sees as a natural sealant for the radioactive material left over from making nuclear weapons.
The process is deceptively simple: Plutonium waste from Los Alamos National Laboratory and a variety of defense projects is packed into holes bored into the walls of rooms carved from salt. At a rate of six inches a year, the salt closes in on the waste and encapsulates it for what engineers say will be millions of years.
“It’s eternity,” said Dirk Roberson, a guide for the frequent tours the Energy Department gives to visitors to the salt mine, who leave with a souvenir plastic bag filled with chunks of salt pressed into rocklike form.
The complications of the present intruded last week, however, when a truck hauling salt in the mine caught fire. Smoke forced an evacuation of workers and a shutdown of waste burial operations, which officials said was temporary. They said the fire did not affect the radioactive waste, which is stored at the other end of the mine.
But the salt behaves strangely around nuclear waste, which is warm to the touch. When the waste is buried in salt, tiny bits of water inside the salt start to move toward the heat. As a result, the salt left behind is stronger, like a good sealant. But it is still basically salt.
“The salt is completely unaffected by any nuclear waste you could imagine, period,” said James Conca, a geologist and former director of the Carlsbad Environmental Monitoring and Research Center, a division of New Mexico State University.
With most things nuclear, however, the politics can be trickier than the science. In the case of WIPP, there is local support but skepticism farther afield.
In the nearby community, business and political leaders are agitating for expansion. John A. Heaton, a Democratic former state representative and the head of the Nuclear Opportunities Task Force, a local business group, argued that the geology was suitable. “The Permian basin is 250 million years old,” he said. “It’s been here a long, long time.” His group has bought a patch of desert and is now exploring whether the land could be used for interim storage of highly radioactive waste.
Burial here, perhaps after recycling usable components, would be a boon for the area, Mr. Heaton added. “Nobody comes in and helps rural areas,” he said. “You have to live by your wits.”
Read more at Nuclear Waste Solution Seen in Desert Salt Beds