The Nuclear Waste Management Organization (NWMO) is focusing its attention on three tracts of land in the region as the possible home for its proposed high-level nuclear waste repository.
Late last month, the NWMO held open houses in four area communities: Elliot Lake and Spanish (April 18-19), Township of the North Shore and Blind River (April 21-22).
In Elliot Lake, as many as 285 people attended over the two days, with as many as 240 being students from local school. In Blind River, the visitors numbered about 80 over two days, including 45 students. In Spanish and the Township of the North Shore, about 15 people in each community attended, says Mike Krizanc, NWMO communications manager.
The three block areas they will be concentrating on are between 40 and 100 kilometres north of the four North Shore communities.
While the NWMO has been looking at this region for the past few years, the research is now far more refined.
Alec Blyth, NWMO section manager – adaptive phase management geoscience, says what they have been using until now were maps done by the Geological Survey of Canada that were made in the 1970s and 1980s. That aircraft flew at height of about 300 metres (985 feet), and the camera covered an area between 800 and 1,600 metres (about a half mile and a mile) wide.
“It gave a low resolution image,” says Blyth.
Now they have a specially equipped airplane to fly over the three areas to develop a very high resolution map. With this geophysics survey, they will fly at an altitude of 100 metres (328 feet) and scan a 100-metre wide swath.
“It’s about eight times the resolution (of the previous survey).”
The airplane will loop through the specified areas. The largest of the three selected areas is about 15 kilometres (9.3 miles) by 20 kilometres (12.4 miles) for an area of 300 sq. km. (115.3 sq. mi.).
“That’s not the size the repository would be. That’s just the area we’re looking at,” says Blyth.
The second area is slightly small than the first while the third is about half that size.
The underground area of the repository would be about two by three kilometres, with the surface footprint being considerably smaller. The repository would also be about 500 metres (1,640 feet) below the surface.
“We’re looking for dull, boring rock that nobody else is interested in, that are not of economic interest to anybody,” explains Blyth.
The airplane will be equipped with a magnetometer and a gravimeter, both of which will help identify the rock structure under the surface.
The magnetometer measures the Earth’s magnet field through the rock.
“That helps us identify the different rock types.”
It is also good to measure fractures and faults in the rock, he explains.
He says they want to stay away from major faults, some of which can run five kilometres deep and a few hundred kilometres long. In the future, those faults could experience movement.
He adds that fractures are common down to about 100 metres. Many of those fractures were caused by the extreme weight of the glaciers during the ice ages. Water travels through the fractures in the rock, which they also want to avoid.
He adds that glaciers tend to affect rock down to about 300 metres.
By going down 500 metres, there would be fewer fractures. Any water found there would have been trapped and not connected to the surface. That water might have been there for hundreds of thousands or millions of years, he explains.
“This is the kind of area we need to be in for our repository.”
The gravimeter’s task is to look at the Earth’s gravity field and measure the density of the rock. It helps determine if the rock is granite or volcanic rock.
A thick, long and wide block of granite, free of fractures and faults, would be good for the repository.
“In this area, we are already confident with the existing data that there is really thick granite here, 10 kilometres thick or more.”
The gravimeter will help find large blocks. What they want to avoid are thin layers of different types of rock.
They would then generate a map with the new information from the two pieces of equipment, which would help to determine preferred areas within larger sectors.
“Ultimately, what we’re looking for is a nice chunk of sparsely fractured rock that’s good and strong, and that water doesn’t move through.”
New burying container
The NWMO also had a display of a section of the new Canadian designed container that the spent fuel rods would be buried in.
Ulf Stahmer, NWMO’s senior transport engineer, says the new containers are 2.5 metres (8.2 feet) long, .6 of a metre (two feet) wide and weigh three tonnes when loaded. Each container would hold 48 fuel bundles.
The spent fuel bundles would be transferred from the transportation containers to the burying containers.
He adds that the NWMO won an award for this design.
The container is made of two-inch thick carbon steel and coated with a copper jacket that is three millimetres thick. It would then be sealed with a lazar weld.
Once underground, the containers would be placed in buffer boxes made of bentonite clay. The gaps in the tunnels surrounding the bentonite clay-covered containers would then be backfilled with clay pellet, he says.
The NWMO has not made any decision on where the proposed underground spent nuclear fuel would be located. There are still nine communities in Ontario interested in possibly becoming the home of the repository. The decision on the location is still several years away.
By KEVIN McSHEFFREY, Elliot Lake Standard, Wednesday, May 4, 2016 11:26:32 EDT PM, as posted at http://www.elliotlakestandard.ca/2016/05/04/nwmo-to-focus-on-three-areas-to-the-north-of-north-shore