Could Canada have a Fukushima-style nuclear disaster in its future?
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Experts mostly downplay the risk, but the country’s only seaside nuclear power plant, at Point Lepreau, New Brunswick, might be in the line of fire of Atlantic Ocean tsunamis that could overwhelm its meagre defences.
The March 11, 2011, earthquake-triggered tsunami that hit Japan’s Fukushima Daiichi nuclear power plant caused a triple-meltdown catastrophe that released unknown quantities of dangerous radioactive material and is still doing so on a daily basis almost three-and-a-half years later. More than 300,000 people were evacuated, and about 120,000 of them are still not allowed to return to contaminated towns, villages, and farms.
The local agricultural and fishing industries were devastated. Overall, more than 19,000 people were killed in the quake and tsunami, and nuclear-industry experts, government officials, and environmental groups are still disagreeing over potential future casualties from radiation-induced cancers.
Point Lepreau the only oceanside nuke
Canada has 19 operating nuclear reactors that supply about 15 percent of the country’s power. Eighteen of those are at three sites in southern Ontario: Pickering (six), Darlington (four), and Bruce (eight), all within 190 kilometressome of them much closerof Greater Toronto, with a population of more than six million, according to the 2011 census. (The Gentilly Nuclear Generating Station in Bécancour, Quebec, shut down in 2012.)
The single reactor at the Point Lepreau Nuclear Generating Station is 14 metres above sea level on the Bay of Fundy, which has the highest tides in the world.
Lepreau, which opened commercially in February 1983 and was scheduled for mothballing after 25 years, restarted in 2012 after a four-year shutdown and controversial refurbishing that went $1 billion over budget. The plant is scheduled to run for another 25 years, until 2037.
Government study shows risk
But historical data on tsunamis in Atlantic Canada, as well as a scientific government report from only two years ago, suggest that the Lepreau plant might be in harm’s way in the event of a future natural disaster.
The Canadian Atlantic coast is much more passive, geologically speaking, than the B.C. coast, with its proximity to the so-called Ring of Fire tectonic-plate processes that generate powerful earthquakes.
The jagged B.C. coastline is also much more susceptible to undersea slippages at river-delta fronts and landslides into steep-sided inlets that can, and have, produced damaging tsunami-style waves.
Newfoundland hit by tsunami from Portugal
The Maritimes, though, have been affected by both locally produced tsunamis and those generated far afield. The devastating (estimated at magnitude 8.5) Lisbon earthquake of 1755 created a tsunami that travelled from southwestern Portugal to Newfoundland, where it was observed to drain the Bonavista harbour for a full 10 minutes before refilling it and flooding surrounding meadowlands. Another one hit there six years later.
The northeast Caribbean area also contains undersea subduction zones that, according to a 2012 Geological Survey of Canada (GSC) tsunami-hazard study, may present a significant tsunami threat, but the potential hazard is poorly understood, requiring much further study.
And according to that GSC study, done for Natural Resources Canada, scientists studying large offshore landslide deposits near the volcanic western Canary Islands know that huge island-flank collapses have periodically occurred there during the past one million years. Computer modelling done in 2001 suggested that enormous tsunami waves, as high as 25 metres on arrival, could radiate across the Atlantic from northwestern Africa as a result of a failure of the Cumbre Vieja volcano on La Palma island.
(The GSC report pointed out that subsequent studies disagreed with some of the original forecast’s wave-amplitude predictions.)
Depression-era wave pounded the Rock
But it was an underwater event much closer to New Brunswick, on the eve of the Great Depression, that should provide the most concern.
On Monday, November 18, 1929, a magnitude 7.2 undersea earthquake struck the southern Grand Banks, about 265 kilometres south of Newfoundland.
The quake caused a huge underwater landslidethe volume of which has been estimated at between 150 and 200 cubic kilometreson the Laurentian Continental Slope that pushed waves at speeds of up to 140 kilometres per hour toward southern Newfoundland’s Burin Peninsula.
Water high as nine-storey building
The first of three waves, measuring between three and seven metres, hit on a clear, moonlit night at about 7:30 p.m. during an unusually high tide. In some narrow bays, the seawater at runup, or maximum inundation, hit heights of 13 and, terrifyingly, 27 metres, the height of a nine-storey building. Twenty-eight people lost their lives, and hundreds of buildings and boats were destroyed.
If the tsunami had arrived a few hours later, while fishing families were sleeping, many more would have died.
Model showed Halifax inundated
The GSC tsunami survey noted that Halifax, Nova Scotia, 640 kilometres southwest of the peninsula, recorded only a 1.25-metre wave in the 1929 incident. However, it referenced a 2010 modelling experiment where a 117-cubic-kilometre slump caused a 13-metre wave to hit Halifax, located 200 kilometres north of the hypothetical failure. Another test, this time of an 862-cubic-kilometre slide with slump and debris flow, resulted in a disastrous 25-metre tsunami striking the busy port city.
(Although, again, GSC noted that a procedural element in the simulation may have overestimated the amplitudes.)
Perhaps it should be reiterated here that the Point Lepreau power plant is 14 metres above sea level, with no extraordinary defences against tsunamis (or even sea surges), as is customary in Japan.
Fukushima wall too low, history ignored
It should also be noted that the 2011 wave that crippled Fukushima was also 14 metres high. The protective seawall at the Daiichi complex was only 10 metres, even though history showed this would probably be insufficient protection. According to the World Nuclear Association (WNA) website, there are records of eight tsunamis with maximum amplitudes greater than 10 metresin some cases much greaterin that area during the past century.
2014 Vancouver Free Press