Canada Nuclear Safety Commission

Nuclear Power Plants in Canada

 

 

The image shows a map of Canada and indicates sites where nuclear power plants are located: Bruce A & B near Kincardine, Ontario, Pickering and Darlington near Toronto, Ontario, Gentilly-2 near Becancour, Quebec and Point Lepreau near St. John, New Brunswick.

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CNSC Staff Integrated Safety Assessment of Canadian Nuclear Power Plants for 2011

Overall performance highlights

CNSC staff concluded, based on inspections and reviews conducted during the year, that Canada’s NPPs operated safely during 2011. This conclusion is based on the following observations:

There were no serious process failures at the NPPs
• No member of the public received a radiation dose that exceeded the regulatory limit
• No worker at any NPP received a radiation dose that exceeded the regulatory limits
• The frequency and severity of injuries/accidents involving workers were minimal
• No radiological releases from the stations exceeded the regulatory limits.
• Licensees complied with their license conditions concerning Canada’s international obligations.

Furthermore, licensees complied with the regulatory request issued in response to the Fukushima accident.

The integrated plant ratings in 2011 were “fully satisfactory” for Darlington and “satisfactory” for all other stations. This is unchanged from the ratings presented in the 2010 NPP Report. (SCA) ratings for the stations ranged from “satisfactory” to “fully satisfactory” in 2011. This is an improvement from 2010 when two SCAs were rated “below expectations” (radiation protection for Bruce A, and emergency management and fire protection for Point Lepreau). The ratings for these two particular SCAs improved to “satisfactory” in 2011.

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 CANADA’S NUCLEAR REACTORS: HOW MUCH SAFETY IS ENOUGH? : Interim Report for the Parliament of Canada

Safety Features of CANDU Reactors

The Committee heard repeatedly that the CANDU reactor is a robust technology that is tolerant of human error and mechanical failure. One witness described it as the safest nuclear technology in the world.

In comparison to the majority of the world’s commercial reactors, which are pressurized, light water reactors (PWR), the CANDU heavy water reactor design has several inherent safety advantages…On the other hand, the CANDU design uses a relatively large amount of zirconium alloy in the fuel bundles – almost four times as much as is present in some light water reactors. This large zirconium inventory gives CANDU reactors a safety disadvantage… Another area of concern is the potential seriousness of a loss of coolant accident. In light water reactors, the power level declines if the cooling water is lost. CANDU reactors, like the RBMK reactor in Chernobyl, however, see power levels increase when coolant is lost. An accident of particular concern for CANDU reactors involves a loss-of-coolant accident together with a failure of the reactor shutdown system. If the fast shutdown fails, the power level can rise dramatically. A violent disruption of the reactor core can occur within four to five seconds and release significant quantities of radioactive material.

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Recent News Stories

Decaying Concrete Raising Concerns at Canada’s Aging Nuclear Plants: At Quebec’s sole atomic power station, Gentilly-2, eroding concrete has prompted federal licensing officials to suggest that any provincial attempt to refurbish and re-license the 30-year-old plant must satisfy federal concerns over the aging concrete’s ability to stand up to another two or three decades of service, Aggregate Research reports. The move comes as economic pressures force nuclear utilities to consider refurbishing and operating their nuclear plants well past their 25- to 30-year initial lives. Refurbishment estimates range from $2 billion to $3 billion. A shutdown is pegged at $1.6 billion. Of particular concern for any “life extension” is the dome-shaped containment building that encloses the 675-megawatt CANDU 6 reactor and serves as the final physical barrier against radioactive contamination escaping into the atmosphere around Becancour, on the south shore of the St. Lawrence River and an hour’s drive northeast of Montreal. Aggregate Research.com (7/10)

A closer look at Canada’s nuclear plants: Reports of two radioactive spills at the nuclear power plant in Point Lepreau, N.B., late in 2011 have raised concerns with the head of Canada’s Nuclear Safety Commission, CBC News reports. In light of the meltdowns at Japan’s Fukushima Daichi plant resulting from the tsunami in March 2011, the CNSC has made numerous assurances regarding the safety of plants in this country. It stressed that none of Canada’s nuclear facilities are on or near fault lines capable of causing a major earthquake. CBC News (1/9)

Storing nuclear waste a $24-billion problem: There are two million high-level radioactive fuel bundles sitting at temporary storage sites in Canada, as the Nuclear Waste Management Organization wrestles with the mandate of finding a community to host a central storage facility for the waste for perhaps tens of thousands of years, CBC News reports. Throw in the facts that the cost of storage could be up to $24 billion, and it shapes up to be a colossal challenge. The process of finding a site for spent fuel has dragged on for decades. After a federal environmental assessment rejected a central storage option in 1998, the waste storage issue languished.  In 2002, the Nuclear Waste Management Organization was mandated by the federal government to find a site and build a permanent, underground storage facility for the waste. The group is moving ahead again with a target of 2035 for a central site. CBC News (8/18/09)

Reactor design puts safety of nuclear plants into question: Canadian nuclear safety regulators say they have underestimated the seriousness of a design feature at the country’s electricity-producing reactors that would cause them to experience dangerous power pulses during a major accident. If reactors are not shut down quickly, their ability to keep radioactivity from escaping would be put to the test, according to an internal commission document. The document says Canada’s seven nuclear stations, which all use Candu technology, have a feature known as “positive reactivity feedback,” in which their atomic chain reactions automatically speed up if the water pumped into the reactors to cool them leaks, one of the worst accidents possible at a nuclear station. If reactors aren’t immediately shut down during this type of incident, positive reactivity leads to a quick snowballing in the pace of nuclear reactions, which in turn could cause potentially damaging overheating. The Globe and Mail (6/28/09)

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