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Lake Huron would dilute radioactive leaks from nuclear waste site, says expert group

Ontario Power Generation wants to build a ‘deep geological repository’ 1.2 kilometres from Lake Huron to house nuclear waste from the Bruce nuclear plant.

The Toronto Star reports that a “federal panel (is) examining Ontario Power Generation’s proposal to bury low- and intermediate-level nuclear waste in a limestone formation 680 metres below the surface, on the shore of Lake Huron. …At the Bruce site, the federal panel has been asking what happens if underground water is contaminated by radiation, and then leaks from the site.”

According to the news report, a four-member expert group advising the federal panel has said that, “The ‘immense’ waters of the Great Lakes will greatly dilute any radiation-bearing water that might leak from a proposed nuclear waste site on Lake Huron… Fast-flowing surface water would also dilute leaking radiation, should the site be located in the ancient rock of the Canadian Shield…” The article adds that, “The group says it’s possible that as much as 1,000 cubic metres a year of water contaminated with radiation might leak out of a site – although it rates the likelihood as ‘highly improbable’.”

In comparing the relative merits of situating the waste site in Canadian Shield granite or limestone at the Bruce site, the expert group says, “The dilution capacity for a site at the Bruce or in the Canadian Shield, the experts conclude, are ‘similar’.”

The Toronto Star notes, “But other characteristics of the two sites are not. The expert group notes that granite is ‘naturally fractured’, and those cracks in the rock can transport radioactive material. That means a site in the Canadian Shield would require more ‘engineered barriers’ to block the cracks. The limestone at the Bruce site – which underlies a good chunk of rural Ontario – doesn’t have those fractures. It’s capped by a layer of shale that is also not liable to fracture. Water can still seep through the limestone or shale, but the process is very, very slow in comparison with the rate at which is can travel through fractured granite, the expert group says. …But both sites would be ‘well within the regulatory requirements for long term safety and environmental protection’, the expert group says.”

“A separate process, run by the Nuclear Waste Management Organization (NWMO), is under way to find a location for a site to permanently bury high-level nuclear waste – which is used fuel. …The NWMO hasn’t yet identified a site, but is examining several options in the Bruce region, as well as in northern Ontario and Saskatchewan.”

The communities in the Bruce region are Brockton, South Bruce, and Huron-Kinloss. In northern Ontario the communities are Hornepayne and Schreiber, both of which are located just north of Lake Superior, while Ignace is on Agimak Lake. In Saskatchewan, Creighton is situated between Amisk Lake, Big Island Lake and numerous other bodies of water.