Any radioactive leak from a nuclear storage site at the Bruce nuclear plant would be subject to “significant” dilution, says an expert group
By: John Spears, Business reporter, Toronto Star, Published on Fri Apr 18 2014
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, says an expert group.
Fast-flowing surface water would also dilute leaking radiation, should the site be located in the ancient rock of the Canadian Shield, the group says.
The four-member group has filed a report with the federal panel 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.
The federal panel asked the expert group to compare whether it would be better to inter the waste at the Bruce site, or in ancient granite formations in the Canadian Shield.
The question of leakage from the site has heated up with the recent release of radiation from a nuclear waste site in New Mexico, the Waste Isolation Pilot Plant, or WIPP.
The WIPP release does not appear to be related to water leakage – it followed an underground vehicle fire in February – but the fact that radiation had escaped at all prompted the federal panel to schedule additional hearings for the Bruce project.
At the WIPP site in New Mexico work teams have re-entered the underground area, but are advancing in stages. They haven’t yet reached the area where the leak originated, and may not get there for days or weeks.
WIPP officials have drawn up an 11-stage scheme for drafting up a plan to re-open the site, and are only at the fourth stage.
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.
The expert group’s report says that wherever the site is developed, any leaking water it will be significantly diluted.
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.” (A thousand cubic meters is equal to a cube measuring 10 metres in each dimension.)
That’s a very small amount, the group says, given that the annual rainfall into Lake Huron is 42 billion cubic metres a year.
And the volume of water already in the lake is 100 times more than the rainfall, or more than four trillion cubic metres.
As for a waste site in Canadian Shield granite, any leakage would flow into active streams and marshlands
“Hence, the volumes of the bodies of water available for dilution at the surface are either immense (Great Lakes) or actively flowing’so the dilution capacity is significant,” the experts conclude.
The dilution capacity for a site at the Bruce or in the Canadian Shield, the experts conclude, are “similar.”