Canada’s nuclear safety regulator again extended a crucial permit for the country’s oldest nuclear power plant on Friday, allowing it to continue operating beyond its original design life.
On Friday the Canadian Nuclear Safety Commission authorized its owner, Ontario Power Generation, to operate the Pickering Nuclear Generating Station for an additional two years, to Dec. 31, 2026. The extended permit applies only to its newest four reactors, Units 5 through 8, which are collectively known as Pickering B. Those reactors entered service between 1983 and 1986.
The licence extension was granted by commissioners Timothy Berube, Marcel Lacroix and Andrea Hardie, who decided OPG would make adequate provisions for protecting the environment and public safety.
Canada’s homegrown reactor, the CANDU, was originally assigned a design life of 30 years, which had been incorporated into CNSC licensing requirements. If followed, they would have dictated that all four reactors shut down for major overhauls or decommissioning years ago. The CNSC, though, amended those rules and extended the station’s licence three times, while imposing more thorough inspection requirements on key components. The Pickering B reactors are now around 40 years old.
Pickering Station, located roughly 30 kilometres northeast of downtown Toronto, employs about 3,000 people and until recently supplied about 11 per cent of Ontario’s electricity. Nuclear power plants play a crucial role in the province’s grid, but their output has declined: Pickering Unit 1 shut down permanently last month, and Unit 4 is scheduled to follow in December. (The other two Pickering A units were idled permanently decades ago.)
OPG said Pickering B’s continued operation is needed because reactors at other stations are offline for overhauls.
Pressure tubes, which are six-metre-long rods that contain fuel bundles of uranium, are regarded as the major life-limiting component in CANDUs. They deteriorate as they age, gradually increasing their propensity to fracture, an event which could lead to a serious accident. Pressure tubes and related components are collectively known as fuel channels.
The main cause of that deterioration is called deuterium ingress, which is measured in parts per million (ppm) of hydrogen equivalent concentration. Previously, Pickering’s licence contained a condition that effectively capped hydrogen concentrations at 120 parts per million.
But in recent years a small number of pressure tubes in Canada have been found to have greatly exceeded that limit. The CNSC removed the 120 ppm limit from Pickering Station’s licence on Friday, and introduced a new requirement that OPG “implement and maintain an enhanced fitness for service program” for its fuel channels.
Familiar patterns of support and opposition emerged during public hearings held by the CNSC in June, with host municipalities emphasizing the plant’s economic importance. A deluge of submissions from nuclear industry contractors, lobbyists and unions also supported the plant’s continued operation, including the Society of United Professionals and the Canadian Nuclear Association.
The CANDU Operators Group, which represents utilities that use those reactors, wrote in a statement that experimental work had confirmed that the station’s fuel channels could operate safely until 2026, and that OPG “will continue with its exemplary safety record in every aspect of its operations.”
Environmental activists such as the Canadian Environmental Law Association recommended the CNSC reject the permit, partly owing to risks associated with the plant’s aging equipment.
“Old nuclear plants are particularly susceptible to accidents,” it wrote in its submission, adding that the dangers of allowing the plant to continue operating are “high and increasing.”
Sunil Nijhawan, a nuclear safety consultant and frequent intervenor before the CNSC, said that OPG’s own estimates showed “that the degradation of fuel channels is widespread; a number of component and system failure mechanisms are fast converging to put the reactor into unsafe operation territory.”
Several First Nations asserted that the plant’s continued operations required their consent, and some also raised concerns about aging pressure tubes. The Mississaugas of Scugog Island First Nation declared in a written statement that it was “not comfortable with the risk management methods being employed by the CNSC and OPG.”
The CNSC found that the licence extension “does not present any novel adverse impact on any potential or established Aboriginal claim or right.”
A second life is planned for the Pickering B reactors following the planned 2026 shutdown: In January, the Ontario government authorized OPG to begin a refurbishment that would return them to service in the mid-2030s.