The Darlington Nuclear Generating Station in Clarington, Ont., on May 23, 2023.Carlos Osorio/The Globe and Mail
Canada’s nuclear safety regulator has recommended that the country’s first new power reactor in decades should receive the go-ahead to begin construction, even though its design is not yet complete.
At a hearing Wednesday, staff from Ontario Power Generation argued that the Canadian Nuclear Safety Commission should grant a licence to construct a 327-megawatt nuclear reactor known as the BWRX-300 at OPG’s Darlington Nuclear Generating Station in Clarington, Ont., about 70 kilometres east of Toronto.
The application received unequivocal support from the CNSC’s staff, despite the fact that several safety questions remain unresolved.
“The level of design information needed for CNSC staff to recommend a licence to construct is not the final design, but the information must be sufficient to ensure that the regulations have been met,” Sarah Eaton, the CNSC’s director-general of its Directorate of Advanced Reactor Technologies, said before the commission.
It would be the first small modular reactor built in a G7 country and among the first globally – although its output would exceed the informal 300-megawatt cutoff for SMRs.
The BWRX-300 is currently being developed by U.S. vendor GE Hitachi Nuclear Energy. Some aspects of its design are based on the Economic Simplified Boiling Water Reactor (ESBWR), which was licensed by the U.S. Nuclear Regulatory Commission in 2014 but never built. The CNSC said the 1,600-megawatt ESBWR underwent significant testing that is “mostly applicable” to its smaller cousin.
OPG, which submitted its application two years ago, is seeking a 10-year licence and plans to build three additional BWRX-300s at Darlington.
A second part of the CNSC hearing, scheduled for January, will hear interventions from the public, including Indigenous communities. OPG has already partly prepared the site – building roads and moving earth – under an earlier licence granted by the CNSC.
David Tyndall, OPG’s vice-president of new nuclear engineering, said the reactor’s design had advanced sufficiently to meet Canada’s regulatory requirements.
One significant unresolved issue, though, is its emergency shutdown systems.
Typically, reactors are required to have two independent shutdown systems. The BWRX-300 would have 57 control rods that could be inserted rapidly into its core by high-pressure water in an emergency to halt reactivity. Should that hydraulic method fail, electric motors would drive them in instead.
Mr. Tyndall assured the commission that the BWRX-300 was designed in such a way that all safety systems “are guaranteed to be fully independent and redundant, which ensures high reliability and fail-safe operation.”
CNSC staff, however, questioned whether the shut-off systems were truly independent because both systems rely on the same control rods. That remained unresolved at Wednesday’s hearing.
To address unresolved issues, CNSC staff proposed that the commission impose three “regulatory hold points” during the reactor’s construction at which work would halt until OPG provided sufficient information to satisfy CNSC staff. Ramzi Jammal, the commission’s executive vice-president and chief regulatory operations officer, would administer the hold points.
Throughout an assessment running more than 1,000 pages, published by the CNSC this summer, staff repeatedly noted missing information in OPG’s submission that they vowed to review once it becomes available.
“In many cases, there is a discussion about a topic, and it’s noted that the design is not complete,” commissioner Jerry Hopwood observed at the hearing.
“It’s not entirely clear to what extent the design has been completed in such a way that the conclusions that support a licence to construct are then justified.”
M.V. Ramana, a professor at the University of British Columbia’s School of Public Policy and Global Affairs who specializes in nuclear power, said the CNSC doesn’t have enough information to answer key safety questions necessary to grant a construction licence. He added that, as the first of its kind, the Darlington SMR’s design is likely to require further significant changes during construction.
“What it does tell me is that OPG really has rushed through this,” he said. “It may be that they don’t feel they know enough about the design and are waiting for information from GE Hitachi, or that OPG is under its own self-imposed deadline to submit this application by a certain date.”
Prof. Ramana said the CNSC’s role as a safety regulator is in conflict with statements its leadership has made in recent years promoting SMRs.
“The CNSC has acted as a cheerleader for small modular reactors,” he said. “This is completely at odds with what a good regulator ought to be doing.”