Nuke Waste . . . less than a mile from Lake Huron!

[Oscar]

Study supports nuclear waste disposal less than one mile from Great Lakes

[ http://www.midwestenergynews.com/2013/0 ... eat-lakes/ ]

Posted on 09/09/2013 by Kathiann M. Kowalski Midwest Energy News

New geology research says radioactive wastes are unlikely to enter groundwater from a proposed Canadian disposal site less than a mile from Lake Huron.

The research raises questions about future disposal on both sides of the border as radioactive waste continues to sit at power plants around the Great Lakes.

Ontario Power Generation is planning an underground disposal site for low and intermediate level nuclear waste at Kincardine on the Bruce Peninsula in western Ontario. The categories include most things in the United States’ classifications for low-level radioactive waste. For power plants, that includes things like contaminated equipment, clothing, protective gear, and cleaning supplies, as well as filters and reactor water treatment residues.

Starting on September 16, the Canadian government’s joint review panel will hold a public hearing on the project’s environmental assessment. Construction could start within two years, says a timetable on the Canadian Nuclear Safety Commission’s website.

Ontario Power’s proposal has sparked concerns from various groups. Critics include the Great Lakes and St. Lawrence Cities Initiative, the Michigan State Senate, Beyond Nuclear, and Stop the Great Lakes Nuclear Dump.

Opposition focuses on the site’s location less than a mile from the Great Lakes, which hold 21 percent of the world’s fresh surface water. More than 35 million people rely on the lakes for drinking water.

Meanwhile, the United States is producing growing quantities of its own radioactive wastes. No current plans call for underground disposal in the United States Midwest. Nonetheless, layers involved in the Bruce disposal site extend under several Midwest states.

Digging deep

Ontario Power’s proposed disposal site is about 1,970 feet (600 meters) deeper than the bottom of Lake Huron. Ontario Power plans to put low and intermediate level radioactive wastes in tunnels within limestone roughly 2,230 feet (680 meters) below ground level. That layer sits beneath a shale layer that’s 660 feet (200 meters) thick.

Geologically speaking, both layers are part of the Michigan Basin. The bowl-shaped, multi-layered region is centered in central Michigan. The region’s layers extend into Canada, Wisconsin, Illinois, Indiana, and Ohio.

A scientific team, led by University of Ottawa geologist Ian Clark, analyzed core samples to see how likely the limestone and shale are to let water flow through.

“If the groundwater isn’t moving, then there’s really no way for the waste to escape,” says University of New Brunswick geologist Tom Al, who worked on the study.

The team’s conclusion, published in the journal Geology, is that any contaminated groundwater would have very little chance of escaping through the rock.

“We found that the shale and limestone package together are an incredible barrier,” says Clark. “Below and above, nothing has penetrated into that zone for these many hundreds of millions of years.”

“This rock material, it’s almost like a steel plate,” agrees Al. “There is no permeability of any kind.” The rock has few pores that can hold water, and those pores are poorly connected.

In geology terms, the limestone and shale layers date back to the Ordovician Period. That era was 490 million to 443 million years ago.

“These waters have been there since before the dinosaurs roamed the earth,” observes Clark.

Geologist Christopher Neuzil of the United States Geological Survey reviewed a draft of the research by Clark’s team. He has also done his own research on the Bruce site, which is currently under review.

Neuzil interprets his data to mean that there’s negative pressure at the Bruce site. If so, that’s another reason why contaminated water wouldn’t escape.

Basically, past glaciers squished down all the layers beneath them. When
the glaciers melted, “the rock wanted to expand back a little bit,” says Neuzil. To the extent any water can flow, it’s probably moving in, not out.

“Very, very slowly, water is being drawn into it,” says Neuzil. “It’s on the order of centimeters per thousand years.” And, he adds, it doesn’t look like the pressures will balance out for another five or ten thousand years.

Neuzil’s estimates of the rocks’ permeability are “very similar to the values” that Clark’s team found. That suggests the rocks are impermeable over the whole disposal area, says Neuzil, and not just near the boreholes.

Writing separately in the journal Eos, Neuzil has also suggested that shales and other clay-rich rocks could safely host U.S. nuclear waste.

“In many cases we can demonstrate, there’s strong indications that they don’t have any fractures that haven’t been detected,” explains Neuzil. Thus, in building an underground facility, “you won’t run into that kind of surprise.”

Meanwhile, in the U.S.…

The Canadian findings are reminiscent of a 2011 report from the Sandia National Laboratory, which identified geologically stable granite deposits in Great Lakes states as a possible candidate for nuclear waste storage.

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Kathiann M. Kowalski is a freelance journalist based in Ohio who writes often on science and policy issues.

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