Storing Nuclear Waste in Shale Underground Could be Safe Long-Term Solution, USGS Scientist Says

Shale and other clay-rich rocks could be used for the long-term storage of spent nuclear fuel, according to a report presented Monday at the 247th National Meeting & Exposition of the American Chemical Society in Dallas.

Shale is the source of the current boom in natural gas production in the US, but its unique sedimentary properties make it an ideal long-term storage solution for spent nuclear fuel, said research leader Christopher Neuzil, a hydrologist with the US Geological Survey.

According to Neuzil, there are nearly 77,000 tons of potentially dangerous spent nuclear fuel currently sitting in storage in temporary above-ground facilities around the US. This fuel will continue to pose potential threats for generations, up to thousands of years from now.

"Surface storage for that length of time requires maintenance and security. Hoping for stable societies that can continue to provide those things for millennia is not a good idea," Neuzil said in a statement, adding that natural disasters, such as the 2011 earthquake and tsunami that struck the Fukushima Dai-ichi nuclear power plant in Japan, can also jeopardize the containment and security of housed nuclear fuel.

Finding a suitable storage solution for spend nuclear fuel is critical, Neuzil said, because even after it's taken out of reactors, it continues to produce heat and harmful radiation.

Neuzil recommends underground shale deposits as a means of storage for spent nuclear fuel. He contends that water contamination is the greatest threat of nuclear waste and one of the biggest risks to long-term storage.

Shale, Neuzil reported at the Dallas meeting, is nearly impermeable and therefore it could be a safe place to store nuclear waste. Other countries, such as France, Switzerland and Belgium already have plans to use shale repositories to store nuclear waste long-term.

Rich reserves of hydrocarbons can eb found in shale deposits around Earth. But the difficulties in extracting these fossil fuels from shale are exactly why Neuzil thinks shale is a good storage option. Shale is nearly impenetrable, so housing spent nuclear fuel in it could be a safe option that's not prone to leaks.

Even if one of the storage containers were to leak while entombed within shale, because water doesn't penetrate the shale, there is little risk of the contamination spreading. And the shake is so thick that it would take millions of years for radionuclides to diffuse through the shale, according to a Bloomberg News report.

Neuzil said that future glaciation would not pose a risk to the storage system. "Damage to waste containers, which will be surrounded by a filler material, is also not seen as a concern," he said.

The sites for shale storage, however, would need to be assuredly removed from any future potential oil or natural gas extraction operations. Nuezel said there are numerous sites around the US that are suitable for storage.