OTTAWA — There’s no need to fear that an earthquake in Canada could cause a nuclear accident like the one in Japan, experts say.
Government data analyzed by The Canadian Press show that hundreds of small earthquakes have rattled Canada’s nuclear power plants over the years with no apparent harm.
Both the federal regulator and Canada’s flagship nuclear company insist the country’s fleet of reactors can hold up to quakes large and small.
“The CNSC would like to reassure Canadians that nuclear power plants located in Canada are among the most robust designs in the world and have redundant safety systems to prevent damage in the case of an earthquake,” says a statement on the CNSC website.
Canada and Japan also use different kinds of reactors. Unenriched, natural uranium fuels the Candu heavy-water reactors, while the Japanese light-water reactors run on enriched uranium.
Atomic Energy of Canada Ltd. — which the feds are trying to sell — has its Candu reactors at five power plants across the country. There are reactors are in Darlington, Pickering and Bruce in Ontario, Point Lepreau in New Brunswick, and Gentilly in Quebec.
Data show that more than 500 earthquakes have struck within 100 kilometres of those nuclear plants — all ranging from micro to moderate — and the National Earthquake Database only goes back to 1985.
The two strongest both hit the Gentilly reactor. An earthquake measuring 5.1 on the Richter scale struck in November 1997 and a 4.1-magnitude quake hit last summer. Neither quake seems to have caused any damage.
By comparison, the Japanese earthquake measured 8.9. That’s more than half a million times stronger than the strongest quake at Gentilly. Earthquakes like the one that hit Japan strike about once a year worldwide.
The rest of the Canadian quakes have been far weaker. Thirty-two earthquakes measured between magnitude 3.0 and 4.0. The U.S. Geological Survey says there are close to 50,000 earthquakes each year that fall within that range of magnitude.
Another 273 earthquakes measured between 2.0 and 3.0. There are about 1,000 such quakes every day.
Two hundred and fifty-seven earthquakes registered below 2.0. There are thousands of such quakes each day and most of them aren’t felt.
Richard Holt, a nuclear engineer at Queen’s University, says reactors are built to take regular shaking: “It’s just a matter of how strong it is, when you shake it around it doesn’t fall apart, basically.”
He pointed out that it was the tsunami and not the earthquake that crippled the Japanese power plant.
Japanese officials have been pumping sea water into its reactors to prevent full-scale meltdowns.
Bruce Power president and CEO Duncan Hawthorne says in some ways it is easier to cool a Candu reactor.
“A Candu is really — in simplest terms — it’s a little bit of fuel surrounded by an awful lot of water. Whereas these other reactor designs are a lot of fuel surrounded by a little bit of water.”
That’s not to suggest one reactor is necessarily any safer than another.
“All commercial power reactors have basically the same level of safety,” said Jeremy Whitlock, who works for AECL but was speaking on behalf of the Canadian Nuclear Society.
“They all have multiple safety systems ... multiple ways to shut a reactor down, multiple ways to cool the reactor. And the difference is in the details of how you achieve that.”