A bright future for clean energy

Amid a fleet of aging nuclear reactors, scientist Peter Tremaine is finding solutions to meet our growing energy needs

 

Story by Andrew Vowles
Photography by Jessica Darmanin

The  “mild-mannered professor” might have been coined especially for Peter  Tremaine. Dressed in a dark blue fleece sweater, grey pants and brown hiking shoes, wearing thin silver-rimmed glasses, and lounging back in a chair with his legs stretched out in his MacNaughton Building office, he looks nothing if not avuncular. What might possibly rile him up? How about his electricity bill?

Smiling, the U of G chemistry professor allows that he’s hardly immune to rising power prices that have sparked complaints from Ontario consumers. Like most homeowners, he says, he does what he can to conserve energy and save money by turning off lights and ensuring adequate insulation. But for him, focusing on electricity costs misses a bigger problem.

“Global warming is more urgent,” says Tremaine, referring to global greenhouse gas emissions from such power sources as coal and natural gas. “Electricity costs for Ontario are a political issue, and that’s important, but there’s a long- term planetary issue: controlling carbon dioxide. That’s not something you can choose not to do.”

Providing needed energy for a growing population while curbing carbon emissions is the ultimate goal of Tremaine’s research. He’s spent more than 30 years studying high-temperature, high-pressure water chemistry found in nuclear reactors. His work is helping to extend the lifetime of existing nuclear power reactors and enabling safe long-term storage of spent fuel. It’s also laying the groundwork for next-generation reactors.

He’ll continue those studies as the holder of a new NSERC/UNENE Senior Industrial Research Chair in High-Temperature Aqueous Chemistry. The chair is worth $2.5 million over five years, and is funded by the Natural Sciences and Engineering Research Council of Canada and by the University Network of Excel- lence in Nuclear Engineering, along with other partners. The latter network brings together universities and industry to support nuclear re- search and development programs in Canadian schools, and to train future nuclear experts.

“Peter is doing work uniquely relevant to CANDU reactors, our homegrown reactor designs — that’s not going to get done anywhere else in the world,” says Jerry Hopwood, a physicist and current president of UNENE. “In the control room of a reactor, your know- ledge of the exact operating state is being helped by Peter’s work.”

Beyond the reactor control room, Tremaine aims to benefit electricity consumers as well as the environment by finding ways to improve nuclear power reactors — what he considers one of the best carbon-free solutions for meeting our energy needs.

“We need every trick in the book to reduce
carbon emissions. Nuclear power
is almost entirely carbon-free.”

In Ontario, hydroelectric power provides about one-quarter of that demand, but it’s not necessarily benign. Electricity from natural cataracts such as Niagara Falls is carbon-free. But damming rivers in order to generate hydro also poses environmental problems, says Tremaine, including the release of greenhouse-warming methane from rotting vegetation submerged in artificial lakes and ponds. Other green sources, notably wind and solar, are essential, but they generate much less energy and require backups when the wind and sun aren’t cooperating. Ontario’s nuclear plants — the Darlington and Pickering stations run by Ontario Power Generation (OPG) and the privately run Bruce Power plant — provide about 60 per cent of the province’s electricity.

Beyond Ontario, Tremaine says cost is the main deterrent to building nuclear power plants. (New Brunswick has a single nuclear plant; Quebec decommissioned an earlier facility.) The infrastructure is expensive to build and maintain, from the costs of stringent environ- mental assessments to refurbishment expenses needed to safely extend the operating life of older plants. Along with many other green energy sources, nuclear power remains more expensive than oil and gas.

Tremaine says we might come to rely more on those sources — including nuclear, as well as energy conservation — if we reckoned in the true costs of relying on fossil fuels. Canada is implementing carbon pricing, and Ontario has introduced a cap-and-trade program intended to limit greenhouse gas emissions. He says even those measures don’t come close to accounting for the full cost of extracting and burning carbon in coal or natural gas to produce electricity if the energy costs of capturing and sequestering carbon dioxide emissions are included. Using today’s technology, long-term carbon dioxide storage would require the energy equivalent of 30 per cent more oil or gas to be burnt — an additional cost not factored into fossil fuel prices.

“We need every trick in the book to reduce carbon emissions. Nuclear power is almost entirely carbon-free,” says Tremaine, whose studies of hydrothermal chemistry are important for both nuclear power production and waste management. “The greenhouse gas problem is huge, and it’s going to get worse. I get more riled up about politicians who ignore the science about greenhouse gases and misrepresent to the public the need to do something now.”

How a CANDU reactor works

The other thing that fires him up is a general failure to recognize that made-in-Canada nuclear power technology is one of our best bets for ensuring a reliable, largely carbon-free and relatively cheap source of electricity into the future. The CANDU heavy water reactor now used in Ontario and New Brunswick, and in a number of countries around the world, was developed largely by Atomic Energy of Canada Ltd. (AECL) during the 1950s and ’60s. Add in this country’s uranium mining and fuel fabrication sector, and Tremaine says, “Canada is a major player in the international nuclear industry.”

CANDU heavy water reactors built between the 1970s and 1990s were designed to run for 30 years, with refurbishment allowing for another 30 years of operation. In 2011, SNC-Lavalin based in Montreal bought AECL’s commercial reactor division, now run as Candu Energy Inc. Various reactor units at the Pickering, Darlington and Bruce stations have been updated or are undergoing refurbishments. Tremaine stresses that CANDU reactors are built to meet rigorous safety standards set by international agencies and by the Canadian Nuclear Safety Commission (CNSC). Those standards are strictly monitored to ensure that a reactor is either shut down at the end of its life or refurbished to extend its lifetime. It’s like the brake linings on your car: “You have to replace them or stop driving. Our research has helped extend the Pickering reactors’ lifetime by about 10 years.”

Although the Pickering site will be decommissioned in 2024, the refurbished Darlington units and Bruce Power station are intended to hum along for decades. Tremaine aims to help ensure their design lifetimes can be met or exceeded: “We want to fine-tune reactor operating chemistry to minimize long-term corrosion of components.”

Sketching diagrams on a whiteboard in his office, Tremaine explains that a CANDU reactor uses heavy water to move heat from the reactor core to a boiler. Steam generated in the boiler then drives the turbine generator that creates electricity. The system uses pipes and tubes to circulate both heavy and normal water in different circuits within the plant. Understanding what happens under a nuclear plant’s high temperatures (250-300 C) and pressures is critical for modelling complicated chemical reactions that, over time, may cause thinning of the tubes carrying heavy water coolant. That thinning may contaminate equipment and cause radiation problems that require costly repair or replacement.

Looking to prevent problems, operators use Tremaine’s work to refine both heavy and light water chemistry. His studies take place in his U of G hydrothermal chemistry research laboratory, using a suite of instruments that’s nearly unrivalled in any university lab. “This is one of the few labs in the world with the equipment and expertise to study these chemical reactions in light and heavy water under the high-temperature conditions relevant to nuclear reactors,” says Jenny Cox, senior research associate and lab manager.

Don’t look for a mock nuclear reactor here. Instead, there’s a variety of benchtop devices, including a pressure vessel (called a “bomb”) as big as a reusable drink cup that works like a pressure cooker for studies of water and chemicals under reactor conditions — minus the radiation. Various instruments allow researchers to identify products of chemical reactions, and chemical concentrations and properties in solution. For some experiments, the lab uses small amounts of depleted (lightly radioactive) uranium.

Nuclear engineers use the results of these experiments to control chemistry in existing nuclear power plants. Tremaine’s research is also intended to help design future generations of power reactors. Canada is among signatories to an international agreement to develop and select a next-generation reactor concept expected to be online in about 25 years. Topping the list is the super-critical water reactor, which would operate at water temperatures up to 600 C. Tremaine says there are plenty of water chemistry questions to answer before that new design is in use.

Other experts are using his work to model conditions for long-term geological storage of spent nuclear fuel. Canada’s Nuclear Waste Management Organization (NWMO) hopes to select a preferred location for the safe, long-term management of used nuclear fuel by about 2024. Tremaine says experts looking for such a contained site need to ensure that their choice is both scientifically sound and socially acceptable. Multiple barriers would be installed to keep contaminants in the repository. Under current models, it would take hundreds of thousands of years for contaminants to reach the Earth’s surface after any container breach. His research will help the NWMO understand and model the movement of those fuel contaminants. All radioactive spent fuel is now stored on-site.

“Nuclear energy is part of what makes
Canada an energy superpower.”

Social acceptance of nuclear energy is perhaps a bigger hurdle. Some people distrust the technology, he says. In 2011, Japan’s Fukushima nuclear plant experienced a meltdown and radiation release after an earthquake-induced tsunami. Closer to home, a meltdown occurred in 1979 at the Three Mile Island nuclear station in Pennsylvania. Both accidents involved a loss of reactor coolant. No incident has occurred in a CANDU reactor that might have prevented cooling of nuclear fuel. Unlike most other commercial power reactors, CANDU reactors have hundreds of pressure tubes containing nuclear fuel bundles. If a tube fails, Tremaine says, it may be isolated and replaced without affecting its neighbours, as happened in 1986 at Pickering.

In his office, an aerial photo hanging on one wall depicts the Whiteshell Laboratories complex formerly run by AECL in Pinawa, Man. That’s where Tremaine landed his first job in the industry in 1975, after chemistry studies at the University of Waterloo and the University of Alberta.

“Nuclear research sounded exciting,” he says. “Canada was just building its first reactors. All of that was exciting. It was the space race in nuclear power.” Recalling being sent for training to the then new Bruce installation on Lake Huron, he says, “I crawled all over the Bruce reactor to provide background for water chemistry research. Once it started up, I realized I had gotten in on the ground floor there. That’s an experience very few people in the industry have ever had.”

Tremaine grew up in Thornhill, Ont. His father, an air force officer, was a “science junkie.” Arguably, so were his sons: Peter’s brother, Scott, is an astrophysicist at Princeton University. Peter came to U of G in 2001 as dean of the College of Physical and Engineering Science, and served in that position for five years. U of G gives Tremaine handy access to other chemists on campus — particularly within his department’s Electrochemical Technology Centre — and to industry connec- tions in southern Ontario. During an earlier 10-year stint as chair of the chemistry department at Memorial University of Newfoundland, he worked on research with Ontario Power Generation. Tongue in cheek, he says, “This is a lot closer to OPG.”

Those industry ties have always been critical for Tremaine. As far back as his own university days, he says, “I wanted something socially relevant.” During a one-year postdoc at McGill University’s Pulp and Paper Research Institute, he got his first taste of collaborative research involving university, industry and government. That model has characterized his research ever since, including the new NSERC/UNENE chair.

“Part of the fun of this is to talk to industry people and understand what problems they are looking at, what needs to be done, working to design a program that addresses a need,” says Tremaine. Those ties have enabled him to sustain a research program that currently involves five grad students, two research associates and three post-docs.

From its beginnings in the 1950s, nuclear power was viewed as an exciting, high-tech industry that could help meet global energy needs, says Tremaine. That early enthusiasm was dimmed by nuclear accidents in the United States, Russia and Japan. But he believes acceptance will grow, particularly as we’re forced to consider carbon-free alternatives. Nuclear energy is part of what makes Canada an energy superpower, says Tremaine.

“We should be approaching oil and gas, hydro and nuclear with sophistication and be world leaders in all three. I’m not sure most Canadians see it that way.” Recalling his early years studying and working in Alberta, he says, “Scratch an Albertan and ask about oil, and you get an informed opinion. It should be the same with nuclear power in Ontario.”


 

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