Could Canada have a Fukushima-style nuclear disaster in its future?
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 kilometres—some of them much closer—of 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 landslide—the volume of which has been estimated at between 150 and 200 cubic kilometres—on 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 metres—in some cases much greater—in that area during the past century.
The earthquakes that spawned them were all of less magnitude than the monster 9.0 temblor of 2011. A June 1896 regional earthquake (estimated at 8.3) that killed more than 27,000 people generated a tsunami with a runup height of 38 metres.
As stated by the WNA: “The tsunami countermeasures taken when Fukushima Daiichi was designed and sited in the 1960s were considered acceptable in relation to the scientific knowledge then, with low recorded run-up heights for that particular coastline. But through to the 2011 disaster, new scientific knowledge emerged about the likelihood of a large earthquake and resulting major tsunami of some 15.7 metres at the Daiichi site. However, this had not yet led to any major action by either the plant operator, Tepco, or government regulators…”
SFU prof warned of undersea slides
With regard to the likelihood of a destructive tsunami hitting Canada’s Maritime provinces, Simon Fraser University’s John Clague, a geologist and professor in the department of Earth sciences, was the lead author of a 2001 paper titled Tsunami Hazard and Risk in Canada. In it, he acknowledged the Newfoundland tragedy and wrote: “The recurrence interval for an earthquake of the size of the 1929 event is probably between a few hundred years and 1,000 years.
“Even if an earthquake of this size were to occur off Canada’s east coast, it might not trigger a tsunami unless it vertically displaced a large area of the sea floor. There is a greater risk that such an earthquake could indirectly generate a destructive tsunami by triggering a submarine landslide, as happened in 1929. A large tsunami-generating landslide could also occur independently of an earthquake, although there is no historical precedent for such an event.”
Massive failures in past
According to the GSC 2012 tsunami-hazard study, though, huge undersea slope failures have occurred in the past, whether caused by earthquakes or not. “Future submarine landslides along the Atlantic continental slope may also trigger destructive tsunamis; mapping has revealed that mass failures much larger than the 1929 slide have occurred in the past.”
All of which brings us back to Point Lepreau.
After Fukushima, the federal Canadian Nuclear Safety Commission (CNSC), which regulates the use of nuclear energy and materials, put together a “robust four-year action plan to ensure we’re prepared for the most extreme events”, according to an in-house interview with the commission’s Luc Sigouin, director of emergency management programs.
Feds say Canadian reactors safe
In that same April 17, 2014, article, Sigouin also said: “Even though tsunamis and very large earthquakes are not events that are likely to occur in Ontario or New Brunswick—where Canada’s operating nuclear plants are located—we’ve taken concrete steps to ensure we’re ready to respond to the most extreme accident scenarios.”
Most of those steps appear to be related to emergency responsiveness, though. Sigouin said that a task force of experts determined that “Canada’s major nuclear facilities are safe, and that our regulatory oversight was comprehensive”.
Lepreau upgrades completed
CBC News reported on April 10 this year that a scheduled 45-day maintenance outage at Lepreau starting this May was partially to “implement improvements related to emergency preparedness that were identified by the nuclear industry following the accident at Fukushima”. CBC previously reported that safety upgrades included a new ventilation system to counter hydrogen explosions and a backup water line for cooling the reactor if the power goes out.
On April 29, Moncton’s News 91.9 interviewed Lepreau station manager Wade Parker regarding earthquake safety measures, including a filtered vent system and water take-up lines. Parker said that even though the plant was unlikely to experience a Fukushima-level event, “we are safer by some of these design changes we made.…We have procedures in place to address…not some of these issues [but] all of these issues.”
News 91.9 reported: “Parker says Lepreau stands 14 metres above sea level, which is more than adequate to withstand a storm surge, which he says we are more likely to experience than a tsunami.”
Quakes not unknown in NB
But as anti-nuclear activist and University of Moncton professor Ronald Babin told Canadian Press just five days after the Japan tsunami: “If you would have asked the Japanese people about 10 days ago if there was any danger of that kind, they would have said everything was okay. They had put the [backup] generators behind a wall that was supposed to protect them. They thought they had all the bases covered.”
Back in April 2011, Lepreau security manager Paul Thompson told CBC that station staff would “never expect” a Fukushima-style emergency because of the plant’s height above sea level and the region’s record of low seismic activity. Seismologist Ken Burke, though, speaking for the Conservation Council of New Brunswick in its opposition to the CNSC granting Lepreau a new five-year operating licence, testified at a public hearing in December 2011 that nearby Passamaquoddy Bay experienced a magnitude 6.0 quake in 1904.
Earthquake "swarm" under Atlantic
And John Ebel, an Earth-sciences professor at Boston College, gave an April 2013 presentation to the Seismological Society of America’s annual meeting that warned about the possibility of tsunamis hitting close by in the northeast U.S.
He said that a “swarm” of 15 undersea earthquakes that occurred in April 2012 about 270 kilometres east of Boston (a similar distance from Lepreau and almost directly south, which would negate the shielding effect of Nova Scotia in the event of a tsunami) was similar to the seismic activity that preceded the 1929 Grand Banks disaster.
Ebel said more research is necessary to properly assess the hazard potential. This echoes Clague’s research suggestion in his study's conclusion, and it is a repeated recommendation of the detailed GSC assessment.
The risk might be low, and the odds against a Point Lepreau disaster might be high. But talk about odds is something you’d expect from gamblers.
And gamblers almost always lose.