•Q&A about the Pickering B nuclear reactor

Publication - April 21, 2008
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How many reactors are at the Pickering nuclear station?


There are eight reactors at the Pickering nuclear station – four at the older Pickering ‘A’ station and four at the Pickering ‘B’ station.  The four Pickering “A” reactors are the oldest commercial reactors in the country, and began commercial operation between 1971 and 1973.  The four Pickering “B” reactors were added on between 1983 and 1985, sharing common safety systems (containment and Emergency Core Cooling) with Pickering “A”.

Why should the Pickering Nuclear Station be shut down and not rebuilt?


The Pickering nuclear station is Canada’s most oldest and dangerous nuclear station, located on the eastern border of Toronto, Canada’s largest city.   Pickering is closer than any other nuclear station in the world.    Because of the high population density, regulatory authorities would not allow a new plant to be built at Pickering today.  

Ontario Power Generation (OPG) has not made an economic case for building the Pickering B reactors.  It would be a risky, multibillion dollar project.  Greenpeace believes these billions of dollars should be invested in cheaper, safer, cleaner and more reliable energy options, such as conservation programs and renewable power.

Why is Ontario Power Generation proposing to rebuild the four reactors at the Pickering B nuclear station?


The four reactors at the Pickering B nuclear station are ageing and OPG has admitted that none of the reactors can be operated safely after 2014.  

To extend the life of the four Pickering B reactors, OPG must carry out what could be called a heart transplant on each of the reactors.   The pressure tubes in the reactor core, or heart of the reactor – which are highly radioactive – must be disassembled and either crushed or melted to reduce the volume, and stored in the new waste storage facility.  It must then rebuild a new reactor core.

Rebuilding the reactors at Pickering B is an complex, expensive and time-consuming endeavor.  Indeed, according to OPG’s project description it will take over 10 years to rebuild all four reactors.

Can rebuilding the Pickering B nuclear power station reliably meet Ontario’s electricity needs over the next ten to twenty years?


No.  One need only take the example of Pickering A nuclear station.  In 1997, 8 out of Ontario’s 20 reactors, including the 4 Pickering A reactors, had to be shut down because of poor performance and safety problems – the largest nuclear shutdown in world history.  To keep the lights on, Ontario was forced to boost production at its coal-fired generation stations, increasing greenhouse gas emissions by 120%.

In 2000, Ontario committed to restart the 4 reactors at the Pickering A nuclear station.  As is the norm with nuclear projects, the restart of the Pickering reactors underwent a five-fold cost over-run, increasing from the estimate of $780 million to $4 billion, and underwent numerous delays, leaving the province with electricity shortages.  In August 2005, the McGuinty government relented and abandoned the restart of final two reactors (units 2 & 3) at Pickering A, citing the high-cost and probable lack of reliability.  

What’s the lesson learned?  Ontario wasted over 5 years and over $2 billion trying to rebuild the Pickering A reactors when it could have invested in other energy options, such as conservation programmes and renewables to meet our energy needs today.

Unlike a nuclear megaproject, renewable energy options and conservation can be deployed quickly and contribute to our energy needs in the near-term and mid-term.  Over time, the deployment of smaller, decentralized green energy options adds up to provide a cumulative energy punch as big as any nuclear megaproject.   Today Germany has 18,000 MW of wind power while Ontario has about 300MW.

Why is the safety of the Pickering nuclear station a particular concern?


There are six operating reactors at the Pickering nuclear station – two at the older Pickering “A” station and four at the Pickering “B” station.

The four Pickering “A” reactors are the oldest commercial reactors in the country, and began commercial operation between 1971 and 1973. The four Pickering “B” reactors were added on between 1983 and 1985.  

The Pickering nuclear station has a greater risk of accident than other stations because the containment and Emergency Core Cooling System are shared between all reactors at the A and B stations.  In addition, the Pickering “A” reactors are the oldest commercial reactors in the country, and because of their age are the only reactors in the western world with only one emergency shutdown system.  

The Pickering station is also closer to larger numbers of people (Toronto) than any other nuclear plant in the world. For that reason, regulatory authorities would not allow a new plant to be built at Pickering today.

What would be the impact of an accident at the Pickering nuclear station?


In the early morning of April 26 1986, reactor 4 at the Chernobyl nuclear station exploded, causing what the United Nations has called “the greatest environmental catastrophe in the history of humanity.” A comparable accident at the Pickering Nuclear Station would have a disastrous impact on the health and environment of Southern Ontario and devastate the economy of Canada’s industrial heartland.

Fallout from Chernobyl contaminated over 140,000 square kilometers, equaling 23% of Belarusian, 5% of Ukrainian, and 1.5% of Russian territory.  As a result, over 1.4 million hectares of agricultural and forested lands in Russia, Belarus and the Ukraine have been removed from commercial production since Chernobyl.

Because of radioactive contamination from Chernobyl, over 350,000 people have been forced to permanently relocate, destroying local economies and communities.  The high cost of resettlement, health care, environmental clean-up and lost agricultural capacity forced Ukraine and Belarus to introduce a ‘Chernobyl tax’ in the 1990s.  

Just thirty kilometers from downtown Toronto, a similar accident at the Pickering nuclear station would decimate Canada’s largest city and require the resettlement of several million people.  

A 1993 study by Dr. Gordon Thompson of the Institute for Resource and Security Studies estimated that a severe accident at the Darlington nuclear station, just east of Toronto, could lead to 200,000 fatalities.    He estimated the economic cost of such an accident would be $1 trillion.

Ontario Power Generation permanently shut down two reactors at the Pickering A nuclear station August 2005.  Why?  

After shutting down the 4 Pickering A reactors in 2000, Ontario committed to restart the Pickering A nuclear reactors at an estimated cost of $780 million.    The restart of the Pickering reactors underwent a six-fold cost over-run and underwent numerous delays, leaving the province with electricity shortages and dependent on increased coal generation. In August 2005, the McGuinty government relented and abandoned the restart of final two reactors (units 2 & 3) at Pickering A, citing the high-cost and probable lack of reliability.    It cost $2.5 billion to restart the first reactors.


The McGuinty government and OPG did not learn the lesson from Pickering A, however.  Just 3 months after abandoning the restart of two reactors at the Pickering nuclear station, OPG started planning to risk billions on rebuilding the Pickering B nuclear station.

How could we replace the electricity produced by Pickering B by 2014?


As the Pickering A fiasco shows, the reconstruction of nuclear stations is no guarantee of cheap or reliable electricity supply.  Nuclear projects typically undergo cost over-runs and long delays.

Unlike a nuclear mega-project, however, renewable energy and conservation can be deployed quickly and contribute to our energy needs quickly, compared to nuclear mega-projects which take at least ten years.  Over time, smaller, decentralized green energy options add up to provide a cumulative energy punch as big as any nuclear mega-project.   

The McGuinty government has set a 10% target of installing 2,700 MW of renewable energy by 2010.  Countries such as Germany and Spain, however, are installing over 1,000 MW of renewable power a year.  There’s no reason Ontario could not do the same and boost its renewable energy and conservation targets to compensate for the loss of Pickering B in 2014.

Is the nuclear industry correct when it says that a Chernobyl-type accident is “not possible in Canada”?


No.  Canada’s CANDU nuclear reactor is no safer than any other reactor design.   Human error, terrorist attack or technical failure could cause a meltdown at any of Canada’s nuclear stations.

Following the accident at the American Three Mile Island nuclear station in 1979, an all-party committee of the Ontario Legislature (the Select Committee on Hydro Affairs) investigated Ontario’s nuclear policies.  In its 1980 report to the legislature, the committee concluded that:

“It is not right to say that a catastrophic accident (in a  CANDU  reactor) is impossible ... The worst possible accident could involve the spread of radioactive poisons over large areas, killing thousands immediately, killing others through increasing susceptibility to cancer, risking genetic defects that could affect future generations, and possibly contaminating, for further habitation, large land areas...
Accidents, mistakes and malfunctions do occur in [CANDU] nuclear plants: equipment fails; instrumentation gives improper readings; operators and maintainers make errors and fail to follow instructions; designs are inadequate; events that are considered `incredible' happen...no matter how careful we are, we must anticipate the unexpected.”

Is the nuclear industry confident that a nuclear accident will never happen in Canada?


No.  Despite nuclear industry claims that a Chernobyl-type accident is “not possible in Canada,” the nuclear industry requires special financial liability protection from the federal government in case of a major nuclear accident.  The federal Nuclear Liability Act limits that amount of financial liability of any nuclear reactor operator to $75 million – a miniscule fraction of the likely actual cost of a nuclear disaster.  

Premier McGuinty says it is “irresponsible” to say that Chernobyl-type accident could happen in Canada because of “Canada's Candu technology.”  Is he right?


No.  CANDU reactors also share the following similarities with the RBMK reactors at Chernobyl:

1.  Ontario’s nuclear stations and Chernobyl are four-reactor stations with shared safety systems. Sharing of safety systems reduces redundancy and increases the risk of radiation release.

2.  Both reactor designs employ fuel channels (as opposed to one large pressurized reactor vessel), including pressure tubes made of the same alloy. These tubes incorporate hydrogen over time, causing tubes to become brittle and breakable.

3.  While most reactors have to be shut down every year or two for refuelling, CANDU and RBMK reactor designs allow for on-line refuelling. This has the potential to improve performance, but it also can increase the length of time without inspection or maintenance. Chernobyl reactor 4 had been operating for over two years non-stop when it exploded on April 26 1986.

4.  CANDU is the only reactor design outside the former Soviet Union, that like the RBMK, has a positive void effect. Steam formation in the reactor core increases reactivity (more nuclear fissions taking place), increasing power levels, causing more steam formation and resulting in a loss of regulation accident.

What have other countries done to avoid a Chernobyl-type accident?


In 2000, Germany committed to phasing out nuclear power and phasing in clean, green renewable energy. Germany’s then-Environment Minister Jurgen Trittin said that phasing out nuclear power was “a logical response to Chernobyl.”

In a referendum following Chernobyl accident, Italy voted to abandon nuclear power completely in 1987.  Italy subsequently closed all of its reactors and placed a moratorium on the construction of new nuclear stations.  

Are airplane crashes or terrorist attacks a concern at the Pickering nuclear station?


Yes.  The federal government is proposing to build an international airport in Pickering and September 11th revealed that all of Canada’s nuclear stations are vulnerable to a terrorist attack.  

It is noteworthy that after the September 11th, the Nuclear Insurance Association of Canada refused to provide coverage for potential terrorist incidents at nuclear stations for such things as air plane crashes.   The insurance industry has acknowledged and is accounting for the potential for a terrorist attack at Canada’s nuclear stations.

Have accidents happened at the Pickering nuclear station?


Yes.  There have been a number of near misses at the Pickering nuclear station.

The following is a selection of these accidents:

Accidents at Pickering Nuclear

Pickering Reactor 2, August 1, 1983
A metre-long break ruptured a pressure tube in Pickering Reactor 2, spilling 17 kg of heavy water per second onto the floor of the reactor vault. The leak rate was gradually reduced as the coolant pressure dropped, and the the leak was stopped two weeks later. A broken fuel bundle left fuel ‘pencil’ wedged in the crack, which greatly complicated the removal of the pressure tube. Inspection of the pressure tubes at reactor 1 showed similar degradation, which resulted in the early retubing of Pickering reactors 1 and 2.
Pickering Reactor 1, November 22, 1988
A fuel failure occurred when a Pickering Reactor 1 operator, working with incorrect operating instructions, increased reactor power from 65% to 87%, causing 36 fuel bundles to fail. The breakdown of fuel bundles in the core was revealed by a sudden increase in the level of radioactive isotope iodine-131. Iodine-131 levels were at 30 times the normal release levels in the last two weeks of December 1988, and 80 times the normal release levels in the first week of January 1989. Ontario Hydro continued to operate the reactor and attempted to remove and damaged fuel bundles between January and May 1989.
Pickering Reactor 2, March 1989
Workers discovered that a 100 square cm hole had existed between the moderator purification room and the moderator room since early 1988. If a serious loss of coolant accident had occurred at some point during those fifteen months, the resulting leakage of water between these two rooms would have damaged the sump pumps, which are required to recirculate water to the Emergency Core Cooling System during a Loss of Coolant Accident.
Pickering Reactor 2, September 25, 1990
Pickering Reactor 2 experienced a “severe flux tilt” (unstable and unbalanced nuclear fission) following the insertion of an adjustor rod into the core Operators spent two days trying to stabilize the reactor by changing fuel bundles, reactor power and the configuration of the adjustor rods. The station management was reprimanded by the Atomic Energy Control Board for not shutting the reactor down right away. A second flux tilt occurred at the same reactor in November 1990, only two months later.
Pickering Reactor 4, November 1990
Moderator room pumps were found seized up at Pickering reactor 4. This situation was estimated to have disabled the Emergency Core Cooling System of that reactor for the previous 11 months. Had a Loss of Cooling Accident occurred during that time, the pumps would not have performed their crucial function of recirculating the water to the Emergency Core Cooling System to keep the fuel from melting.
Pickering “A” and “B”, 1990
During a test of the containment system at Pickering that is carried out only once every ten years, a seal on the Pressure Relief Duct failed at about one half the pressure it was designed to withstand. It was estimated that containment at the Pickering site was inadequate for 7.5 years prior to the test which revealed the weak seal. Work on the seals was not completed until June 1995. This could have allowed serious radiation releases in the event of an accident.
Pickering Reactor 4, June 1991
A faulty valve on a steam generator resulted in a 15,000 litre leak of heavy water at reactor 3. the reactor was just being re-started following retubing work carried out over the previous two years. While it was reported that no water leaked out of the steam generator area into Lake Ontario, there were airborne releases of tritium (a radioactive form of hydrogen) in the four hours immediately following the accident.
Pickering Reactor 1, August 2 1992
A heat exchanger was damaged by debris from a broken strainer, spilling over 2,000 litres of radioactive heavy water into Lake Ontario. The spill began at about 1:30 a.m. and lasted for 6 hours. The problem was not noticed by Ontario Hydro staff until 4:50 a.m., and was not stopped for an additional one and a half hours.
This was the largest single tritium spill ever to occur at Pickering. Sampling of local drinking water for tritium revealed significant increases, despite dilution over four days and the five kilometers of waterfront between the Pickering reactors and the Ajax water supply facility, the closest municipal water intake. The Ajax water plant was not shut down at the time, and the public was not notified, so those at most risk (pregnant women and young children) did not have the option of avoiding contaminated drinking water.
Pickering Reactor 4, April 15, 1996
A leaking heat exchanger spilled 100 litres of radioactive heavy water into Lake Ontario. The leak was discovered at 9:40 p.m. and was halted two hours later at 11:50 p.m. As a result of the spill, Durham Region shut down Ajax water treatment plant for about 24 hours.
Pickering Stations A and B, April 16, 1996
Workers discovered a malfunctioning valve associated with the Emergency Core Cooling System. After delaying several days (while former Prime Minister Chrétien was promoting CANDU reactors in Eastern Europe), Ontario Hydro announced the first unscheduled shutdown of all eight reactors at both Pickering nuclear stations. The shutdown took place on April 20 and 21. Hydro said that it expected to take about ten days to repair the safety system.
Pickering Nuclear Station, August 14, 2003 - At the time of the great blackout in eastern North America on August 14, 2003, the Pickering B reactors # 5, 6 and 8 were operating at or near full power and reactor # 7 was being restarted following a planned maintenance outage. Pickering A reactor # 4 was just being started up after being shut down since 1997, and was operating at 12% power, but was not synchronized to the grid.
A significant design flaw in the Pickering station’s emergency shutdown system was underscored by the blackout. The U.S.-Canada Power System Outage Task Force noted that “[e]quipment problems and design limitations at Pickering B resulted in a temporary reduction in the effectiveness of some of the multiple safety barriers…”.
Most notably, the Pickering station’s Emergency Core Cooling System (ECCS), which is used in the case of a Loss of Coolant Accident was designed to operate from grid supplied electricity. When the Pickering nuclear station was disconnected from the grid, the ECCS was unavailable for approximately 5.5 hours, meaning that it would have been impossible to replace coolant if a Large Loss of Coolant Accident (LLOCA) had occurred during that time.
Several emergency low pressure and high pressure water pumps used for cooling also failed to operate as intended. Operators were required to intervene manually to ensure safe shutdown.
Because of the serious problems with the ECCS during the blackout, Canadian Nuclear Safety Commission staff rated the emergency shutdown of the Pickering station as a Level 2 incident on the International Nuclear Event Scale.
Pickering B, December 26, 2003 - It was discovered Emergency Core Cooling System would have been unavailable in the case of a Loss of Coolant Accident (LOCA) and Loss of Electricity Supply (LOBES) incident because of a problem with the Site Electrical System. The system was unavailable for 7 hour and 38 minutes.

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