The Tunnel Vision
The federal fixation on Yucca Mountain now spans two decades. Beginning in the early 1980s, the government agreed to take waste from any nuclear utility that paid a tariff of a tenth of a cent per kilowatt-hour generated by its reactors. All the companies quickly signed up. But the selection of Yucca, 150 kilometers northwest of Las Vegas, was never driven by science. The site was chosen by that august group of geologists and physicists, the U.S. Congress. So far, the Energy Department has spent about $6 billion on development, including building an eight-kilometer, U-shaped tunnel through the mountain, in some places nearly 300 meters below the surface. It plans to spend at least $50 billion more to build dozens of side tunnels, package the waste in steel containers that look like the tanker portion of a gasoline truck, place the waste in the tunnels, and operate the site for 50 to 100 years before sealing it for eternity.
Problems have plagued Yucca since the beginning. In Senate debate, proponents stressed how dry it is. Yucca is, in fact, located in what is now a desert. But it turns out that the ground is moist. Even the 19 or so centimeters of rain the mountain gets each year is a major problem. Over time, moisture can corrode even the best alloys known to man. Corrosion would mean that rainwater percolating through the ground could carry radioactive materials with it and convey them to irrigation systems and drinking-water wells in the region, delivering substantial doses of radiation to unsuspecting people generations hence.
Heat is another problem. The shorter-lived radioactive isotopes in used fuel, principally cesium-137 and strontium-90, give a single fuel assembly, fresh out of the reactor, a heat output equal to that of about 20 handheld hair dryers. That’s why each power plant has an adjacent storage pool that circulates cooling water. Once the fuel was underground at Yucca, it would be hot enough to boil ground water into steam. Steam could corrode the containers or break up surrounding rock, raising uncertainty about secure burial. Spreading the waste out would dissipate the heat, but it would also greatly reduce Yucca’s storage capacity. Then there’s the problem of radioactive decay. High-energy particles can interact with surrounding materials, breaking them down or causing them to give off hydrogen, a gas that can explode or burn.
Early this year, researchers at Catholic University of America, hired by the state of Nevada, took samples of the kind of metal the Energy Department wants to use at Yucca and put them in some water mixed with the minerals present in the mountain. As a series of speakers lectured reporters on why Yucca was a bad idea, the researchers sautéed the metal over a burner. By the time the lectures were done, the samples had corroded, some of them all the way through. How faithfully the stunt reproduced the chemistry of Yucca Mountain is debatable. But clearly, Yucca is subject to serious doubts. “You have to think somewhere back in the premise structure of the whole thing, something was dreadfully wrong,” says Stewart Brand, a San Francisco-based consultant who once advised the Canadian government on what to do with its own waste.