Individually, they're no larger than your pinkie.
But the energy-packed pellets that are the radioactive remains of nuclear power generation pose an enormous problem for nuclear energy plants that weren't originally designed to store them.
So far the 103 operating nuclear reactors in the United States have generated an estimated 45,000 tons of waste that is expected to remain radioactive for more than 200,000 years.
And right now, the waste, which emits radioactive particles that can eat away at human tissue and organs, is being stored in tanks or concrete and steel bunkers at sites that were only meant to contain the waste for perhaps decades, not centuries.
"Spent fuel is now stored in pools and dry casks," says Rodney Ewing, a professor in nuclear engineering at the University of Michigan. "Today it's safe. But it's certainly not a long-term solution."
Shoot It into Space or Bury It?
Some argue the lack of a permanent, safe storage site for nuclear waste is reason enough to oppose proposals in President Bush's energy plan, unveiled today, to speed licensing of new nuclear power plants and extend the operating licenses of existing plants. As Allison Macfarlane, a geologist and senior researcher at the Massachusetts Institute of Technology says, "Until we can figure out what to do with the waste, we shouldn't make any more of it."
But those who tout the economic and environmental benefits of nuclear energy argue a safe, permanent storage site has already been found and only politics has prevented its opening. Others point to changing methods of nuclear power generation that could ultimately reduce waste production (see sidebar below).
Some have proposed rocketing nuclear waste into space where it could linger and eventually decay beyond Earth's orbit. But that idea has since been dismissed as prohibitively expensive and dangerous (imagine a Challenger-like disaster on a craft containing nuclear waste).
Others are working on ways to convert nuclear waste into less-harmful materials using a process called transmutation. But that technology, which would attempt to accelerate particles into the atoms of radioactive material, remains unfeasible.
The best solution, most agree, is to contain nuclear waste deep in the ground. The logic is this: containers underground are like submarines in deep water. As a boat on the water's surface is tossed around by stormy waves, a submarine is barely disturbed. Likewise, nuclear waste underground is less likely to be disturbed and then leak.
But, as many scientists point out, there are factors such as volcanoes and earthquakes that could disrupt even deep underground holdings.
According to legislation passed in 1987, the federal government should have begun operating a permanent underground storage site by 1998 at Nevada's Yucca Mountain, located about 100 miles northwest of Las Vegas. Tunnels burrowed 600 feet below the mountain's surface would host about 70,000 tons of waste.
After nearly two decades of research and federal spending of nearly $6.7 billion, the department of energy released an summary report for public review this May that concluded while uncertainties remained, the repository would be safer than current options.
"The science strongly supports that the site is suitable," Joe F. Colvin, chief executive officer of the Nuclear Energy Institute in Washington, D.C., said recently about the report. "We expect the decision process, based on scientific facts, to move forward in an expeditious manner."
Still, scientists and citizens — especially those based in Nevada — argue the mountain location is not safe enough.
Yucca Worries: Water, Volcanoes, Shakes
Judy Treichel, executive director of the Nevada Nuclear Waste Task Force, a non-profit public advocacy group opposed to the Yucca plan, argues the ground around the Yucca site is too active. Nevada ranks third in the country for seismic activity and M.I.T.'s Macfarlane points out there are three volcanic cones located within 10 miles of Yucca Mountain. She says if one should erupt (an event that geologists have estimated is unlikely), "it would spew nuclear material all over the place."
Water is another big worry. Nevada geologist Steve Frishman and others have found that water seeps through the mountain much faster than researchers originally thought. If water can reach the cask-contained waste, Treichel argues, then it can also carry the radiation to groundwater supplies.
Finally, some scientists have questioned the durability of the material that would contain the nuclear waste. According to the plan as it's now written, the canisters would be built from a nickel alloy. Although studies show the material to be strong, there are no long-term studies on its performance.
"In Sweden they use a copper canister — and we have very long-term data on copper's durability," says Ewing. "This material they want to use appears to be strong, but we have no way of knowing if it will break down, say, 500 years from now."
In fact, Ewing has questioned the whole approach that DOE scientists have taken in assessing the safety of the Yucca site. He argues that since so much of the evaluation has been based on estimations, an accurate conclusion about whether the mountain location would be safe is impossible. It would be better, he says, to locate other possible sites and then compare them.
"The Yucca site may be adequate," he says, "but it's difficult, even impossible to say that now with confidence."