The Pickering Nuclear Station has a long history of operational problems, accidents and poor performance.
Interview with Dr. Frank Greening, retired nuclear researcher on why the Pickering Nuclear Plant presents serious safety concerns.
The four Pickering “A” reactors are the oldest commercial reactors in the country (and some of the oldest in the world), and began commercial operation between 1971 and 1973. The four Pickering “B” reactors were added on between 1983 and 1986.
The Pickering nuclear station has a greater risk of accident than other stations because the containment system’s vacuum building is shared between six operating reactors. The Pickering A reactors also lack two completely separate shutdown systems, the norm for modern nuclear plants. As a review by world-recognized nuclear expert Arnold Gunderson stated, “At the Pickering site, there is only one overall safety related containment system when there should be six separate safety related containment systems. This design flaw has created a cumulative risk at the Pickering station that is higher than that at any single unit station in Canada.” Gunderson notes that, in particular, this design flaw makes the eight-reactor plant particularly at risk for the kind of cascading accident seen at Fukushima, where damage to one reactor led to fires and explosions that damaged adjacent reactors.
Here’s a brief summary of some of the plant’s problem-plagued history:
Throughout its operation, Ontario Hydro reported other significant events at the Pickering station to the AECB. Among them were the following:
On August 1, 1983, Pickering reactor 2 had a loss of coolant accident after a pressure tube suffered a metre-long rupture. The station was shut down and the four reactors at Pickering A were eventually retubed at a cost of about $1 billion.
On November 22, 1988, an operator error damaged 36 fuel bundles. The cooling system was contaminated by radioactive iodine that was vented into the environment over several weeks following the accident.
On September 25, 1990, Pickering reactor 2 experienced large power shifts in the reactor core. Staff spent two days trying to stabilize it before shutting it down. The AECB later criticized the utility for not shutting down immediately.
On August 2, 1992, Pickering reactor 1 had a heavy water leak from a heat exchanger that resulted in a release of 2,300 trillion becquerels of radioactive tritium into Lake Ontario.
On April 15, 1996, Pickering reactor 4 had a heavy water leak from a heat exchanger that resulted in a release of 50 trillion becquerels of tritium into Lake Ontario.
More recently, the station has continued to experience problems:
In July 2007, OPG was heavily criticized for failing to act promptly to fix a leak in Pickering’s radiation containment system. Observers speculated that OPG might be failing to act promptly because the repair could require shutting down all four reactors in the Pickering A plant, due to the plant’s unusual (and unsafe) reliance on a single shared containment system.
In March 2011, there was a leak of 73,000 litres of demineralized water into Lake Ontario at the Pickering A nuclear generating station. While contending that there was no risk to the public, OPG acknowledges that this kind of leak was not acceptable, especially considering the Great Lakes are the source of drinking water for millions of people.
In September 2015, an unexpected “system trip” led to the sudden shutdown of a reactor at Pickering, leaving the province scrambling to import replacement power. The trip came at a particularly difficult time as a number of the province’s other reactors were also shutdown at the time for repairs.
Shared containment building for multiple reactors, greatly increasing the odds of cascading failures
An overly complex design with miles of piping prone to leaks
Significant risk identified by OPG itself of a steam generator failure that could lead to a major radioactivity release
Foundations and other concrete weakened by 45 years of Canadian winters and freeze-thaw cycles. At a U.S. plant 15 years younger than Pickering, concrete was found to have weakened by 25%.
A serious design flaw that causes the reactor core to power up when there is a loss of coolant accident, a perfect recipe for a meltdown.
As the author notes, “Quite simply, nuclear plants like those at Pickering should not be allowed to operate based upon mysterious unfounded calculations or operating confidence levels as low as 70%. While both OPG and CNSC claim that extending the life of the Pickering Nuclear Generating Station is based upon hard data and pure scientific analysis, it appears that there is a considerable amount of guesswork underlying each