by Wendy Koch, USA TODAY
Shale is already a source of the U.S. natural gas boom, but new research suggests it could help the expansion of another energy source: nuclear power.
Could shale rock spur another energy bonanza? It's already helped create a surge in U.S. oil and natural gas production, and research today suggests it could do something else: store radioactive waste from nuclear power plants.
These rock formations are ideal for storing potentially dangerous spent fuel for millennia, because they are nearly impermeable, a U.S. geologist told a scientific meeting. One of the biggest risks of storing nuclear waste for thousands of years is water contamination.
The development of new U.S. nuclear power plants, all of which are now decades old, has been partly hobbled by the lack of a long-term repository for their waste. In 2009, the U.S. government abandoned plans for a repository at Yucca Mountain in Nevada, so plants currently store about 77,000 tons of spent nuclear fuel onsite in above-ground facilities.
"Shale has a lot of nice properties. ... We really should consider whether this is something we should look into," says Chris Neuzil of the U.S. Geological Survey, who presented his findings Monday in Dallas to the annual meeting of the American Chemical Society. He says experiments show how incredibly watertight shale can be — 100 to 10,000 times less permeable than cement grout.
"Not all shales have the low permeabilities at the scale we desire," but plenty is available in tectonically stable areas that won't be used for oil and natural gas production, Neuzil says. In recent years, hydraulic fracturing, or "fracking," is being used to break apart these rock deposits and extract the the gas or oil trapped within.
Neuzil says current U.S. storage of nuclear waste is problematic because the spent fuel continues to produce heat and harmful radiation long after a power plant uses it to produce electricity. Plants typically store the waste in steel-lined, concrete pools filled with water or in massive, airtight steel casks.
Neuzil says safe maintenance of above-ground storage depends on stable societies for thousands of years. He also notes the risks of natural disasters, including Japan's 2011 tsunami that knocked cooling pumps offline at the Fukushima Daiichi nuclear power plant.
Several countries, including France, Switzerland and Belgium, have plans to develop long-term nuclear waste repositories hundreds of yards underground in layers of shale and other clay-rich rock. Neuzil is investigating a site using limestone in Ontario with the Canadian Nuclear Waste Management Organization.
"He's bringing up a very sensible idea, but this isn't particularly new," says Mick Apted, a geochemist at Austin-based INTERA, an environmental consulting firm. "The Europeans have taught us this."
Apted, who's working with Switzerland and Belgium on their programs, says France is furthest along in pursuing an underground repository in clay-rich rock, which isn't as hard as shale. He says France, which gets 80% of its electricity from nuclear power, has identified a site. In Finland and Sweden, he says, companies have submitted a construction license to build a repository in granite-like rock and are waiting on government approval.
"It's far too soon to know" whether shale is a viable long-term storage option, says Geoff Fettus, an attorney in the nuclear program at the Natural Resources Defense Council, an environmental group. He says prior research has looked at the feasibility of various geologic formations, but "NRDC is not aware of a significant number of studies on this particular medium (shale)."
In his January 2010 State of the Union address, President Obama received standing applause from both sides of the political aisle when he called for a "new generation of safe, clean nuclear power plants." In February, his administration finalized $6.5 billion in loan guarantees for the nation's first two new nuclear reactors in three decades — at Southern Co.'s Vogtle nuclear power plant in Georgia.
The expansion of nuclear power, welcomed by the nuclear industry and business groups such as the U.S. Chamber of Commerce, remains controversial in the environmental community. Many environmentalists oppose it, citing potential Fukushima-type meltdown risks as well as the lack of a long-term repository for nuclear waste.
Yet in recent years, it's drawn the support of leading climate scientists, such as James Hansen, former head of the NASA Goddard Institute for Space Studies, who say solar and wind energy will not be able to deliver enough carbon-free energy to avoid catastrophic global warming. Nuclear power plants emit no heat-trapping greenhouse gas emissions.