How many dead fish would be “significant”?

By Krystyn Tully, Waterkeeper.ca Weekly September 19 2012 

A nuclear power plant in Ontario should be allowed to kill millions of fish each year, say staff of the Canadian Nuclear Safety Commission (CNSC). Their surprising recommendation is part of the final environmental assessment report for Ontario Power Generation’s plan to refurbish four nuclear reactors at its Darlington Nuclear Generating Station on the north shore of Lake Ontario.

CNSC staff are asking Commissioners, acting together with the Department of Fisheries and Oceans, to allow OPG to operate a “once-through” cooling system. This outdated system will suck in water from Lake Ontario to cool the nuclear reactors, then discharge warmed water back to the lake all day every day for a half-century.

Such systems are rarely approved in the U.S., say leading authorities; American environmental regulators such as New York State’s Department of Environmental Conservation are even pushing existing power plants to replace antiquated “once-through” systems with modern cooling towers. Cooling towers use 98% less water and kill 98% fewer fish.

CNSC staff agree that closed-cycle cooling would protect fish, but say that U.S. rules do not apply in Canada and that a closed-cycle system “may or may not” be required some time in the future. In their view, the millions of fish, eggs and larvae destroyed at Darlington each year are “insignificant.”

“The government paid Waterkeeper’s experts to offer advice for building and regulating a cooling water system that would minimize impacts on fish and fish habitat. If they believe fish kills are acceptable, why did they bother? Why ask for information about U.S. regulatory approaches if, at the end of the day, the CNSC believes Canada has nothing to learn?” asks Waterkeeper Mark Mattson. “We’re baffled.”