Northland rock considered for nuclear waste storage

Dec 27 - Duluth News-Tribune (Duluth, Minn.)

With Nevada's Yucca Mountain out of the running as the permanent graveyard for U.S. nuclear waste, scientists now are looking for other places to entomb the stuff, including rock formations common in northern Minnesota and Wisconsin.

That's the message from a 114-page study from the Sandia National Laboratory that surfaced last week.

While there's no official effort under way to pick a specific nuclear waste repository, the study said areas where earthquakes are rare and that have stable rock in the granite family may be the best candidates.

That could be any area of the East Coast, from Georgia to Maine, where granite is common. But the study also notes the Lake Superior region of Minnesota, Wisconsin and Michigan's Upper Peninsula is "the most stable region of granite outcrops in the U.S."

That makes geologic sense to Steve Hauck, geologist for the University of Minnesota Duluth's Natural Resources Research Institute. Not only does Minnesota have lots of "granitic" rock, but we haven't had a volcano or significant earthquake here in millions of years -- the kind of geologic stability you'd want if you were trying to entomb deadly nuclear waste for several millennium.

"We're sitting on one of the most stable areas of North America, called the Canadian Shield. Most of our granite is 2.5 billion years old and older," Hauck said. "I think what they are probably going to look for is homogenous granitic, or plutonic, rock where the grains are the same size."

There are vast areas of Minnesota covered with formal granite -- from the Minnesota River Valley through Stearns County in central Minnesota up to Duluth, and across much of Northwestern Minnesota. The Iron Range is underlaid by granite, Hauck noted, but that might not be a great site to store nuclear waste.

"There's been a lot of blasting up there for the past 100 years. A lot of that rock is fractured," he noted. "That's probably someplace they'd want to avoid. You don't want fractures where radioactive waste could escape."

Expand the definition of "granite" a bit and you can include gabro and other rock that's just as stable as granite with similar properties. It's found across Northeastern Minnesota, very close to the surface for easy access and easy analysis.

While not formal granite, the Arrowhead is part of the region the Sandia report highlights.

"You'd probably want something you could walk across and characterize (map) without having to dig through hundreds of feet (of dirt). And there's a lot of that rock at the surface across most all of Northeastern Minnesota," said Harvey Thorleifson, director of the Minnesota Geological Survey of the University of Minnesota.

Thorleifson said the biggest issue wouldn't be if northern Minnesota has the right kind of rock to entomb radioactive waste, but whether state residents would ever accept it. He noted the Canadian government found suitable sites just across the border from Minnesota in Ontario but never placed any waste there.

"The obvious areas of granite are the Minnesota River Valley, Stearns County and northwestern Minnesota," said Val Chandler, a geophysicist with the Minnesota Geological Survey. "But the Arrowhead, especially north of the Iron Range, has a lot of exposed granitic bodies that aren't specific granite but are in that same" family of rock.

That exposure means the Arrowhead's rock is easy to get to, has been well studied and that scientists already know it is solid and stable, Chandler noted.

It's not the first time Minnesota has been eyed to store nuclear waste. Chandler reviewed technical papers nearly 30 years ago for federal geologists who were scouring Minnesota as a potential site for nuclear waste. The most critical characteristics they look for include how rigid, uniform and strong the rock is. Whether it's "crystalline" or fresh rock also plays a role. And how groundwater moves in the area is key.

"Back in the '80s they looked at general areas and what kind of data was out there, but I don't think they ever got as far as a field study on any specific sites," Chandler said. "There was a lot of controversy with the public about it all. And then attention turned to Nevada and everything here in Minnesota faded away. Until now."

There are 104 operating commercial reactors in the U.S. with plans still in the works to build about 26 more. Radioactive waste is now stored in temporary casks at 120 sites in 39 states, according to the U.S. Department of Energy. That includes casks in Minnesota near the Mississippi River outside the Prairie Island nuclear plant at Red Wing.

Congress in 1987 named Yucca Mountain as the site to dispose of what's now approaching 77,000 tons of nuclear waste waiting for a permanent home and which will remain radioactive and deadly to humans for centuries, possibly tens of thousands of years.

But the Obama administration declared in February 2009 that Yucca Mountain won't work, after nearly $15 billion was spent building the facility.

"The new administration is starting the process of finding a better solution for management of our nuclear waste," an energy department spokeswoman said nearly three years ago.

In July, with little fanfare, the Obama administration's Blue Ribbon Commission on America's Nuclear Future released a draft report to the Secretary of Energy on a post-Yucca Mountain solution. The report calls for development of "one or more geologic disposal facilities."

"Deep geological disposal is the most promising and accepted method currently available for safely isolating spent fuel and high-level radioactive waste from the environment for very long periods of time," the commission concluded in its report.

But the commission stopped short of deciding how the federal government will move forward in what's certainly to be a socially and politically charged battle to find a specific home or homes for the nation's growing stock of radioactive waste.

Then, in August, the Sandia National Laboratory in Albuquerque, N.M., a division of the U.S. Department of Energy, quietly released its study that highlights where to look for alternatives to Yucca Mountain. The report titled "Granite Disposal of U.S. High-Level Radioactive Waste" was first featured in an Associated Press story last week, the first time it became public.

So far, federal officials say they haven't even started looking for a specific state or single site.

"There is no leading candidate of any kind, because there is no program at the moment for siting repositories," Andrew Orrell, director of nuclear energy and fuel cycle programs at Sandia, told the Associated Press.

Orrell noted that in addition to granite, salt beds, clay, shale and deep holes bored into the earth in other locations -- as deep as three miles down -- could be potential resting areas for the nation's nuclear waste.

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