What’s an SMR? Canada’s bet on the contentious next-gen nuclear tech, explained

"Are SMRs viable? That is the biggest question surrounding SMRs. Although the plans for these next-generation nuclear units might hypothetically work, their viability hasn’t been proven anywhere. 

Jan. 4, 2023

Canada has big climate goals and we need ambitious solutions to meet them. The federal government is banking on a new generation of nuclear technology to help us clean up power grids and reduce planet-warming greenhouse gas emissions. But will it work?

As part of a new Canada’s National Observer series breaking down climate basics, we delved into some common questions about the next phase of nuclear tech — SMRs.

What is an SMR?

An SMR, or small modular reactor, is a nuclear power unit used to produce energy. As of now, SMRs don’t technically exist; no unit has been fully built. But like nuclear energy in general, the tech is especially polarizing: while many — including the federal government — tout SMRs as a way to reach net-zero greenhouse gas emissions and achieve our climate goals, others say the risk they pose heavily outweighs any potential reward.

SMRs create energy through nuclear fission, similar to traditional nuclear reactors. That process creates heat, which generates electricity but doesn’t create greenhouse gas emissions, unlike fossil fuel energy sources such as coal and natural gas.

What does SMR stand for, and how are they different from existing reactors?

SMR stands for small modular reactor. Here’s a word-by-word definition.

Small: SMRs have a smaller energy output compared to traditional nuclear reactors. For example, the Point Lepreau nuclear generating station in New Brunswick has one reactor with a power capacity of 705 megawatts of electricity (MWe) and supplies around 40 per cent of the province’s power. SMRs, on the other hand, will have a power capacity of up to 300 MWe per unit, according to the International Atomic Energy Agency. Take, for example, one SMR that's set to be built in Ontario: at its maximum output, the unit could power 300,000 homes, according to Ontario Power Generation. However, not all SMRs in Canada will have that much power — another planned SMR in New Brunswick will produce just 100 MWe.

Physically, the size of SMRs will vary depending on power output, according to Ontario Tech University. Small SMRs will be the size of a large SUV situated on a gas station-sized lot. Larger ones could be as big as a semi-trailer and require a lot the size of a football field.

Modular: According to the federal government, this means the reactors “are factory constructed, portable and scalable.” Compared to traditional nuclear plants, which are built from the ground up, SMRs can be constructed in a central factory and shipped elsewhere as a whole. However, that process will rely on how much demand there is for SMRs and how feasible it is to ship the units once they’re built. Because SMR technology is still in its early stages, this is still to be determined.

Reactor: The type of reactor an SMR uses can vary. According to the Canadian Nuclear Safety Commission, SMRs can use different types of fuels to power their reactors. In Canada, all existing nuclear power stations have CANDU (Canadian Deuterium-Uranium) reactors, which use natural uranium mined in Saskatchewan as fuel and heavy water (which differs from regular water because it has significant amounts of deuterium, an isotope of hydrogen) to cool and moderate the reactors.

SMRs, on the other hand, could use a number of reactors. One company in New Brunswick is slated to build a molten salt reactor that uses spent nuclear fuel, usually stored as nuclear waste after being used by reactors. As part of the process, the company would recover plutonium mixed with other substances to fuel the reactor, a process that has never been accomplished commercially, which critics have raised proliferation concerns about.

Another company in New Brunswick is developing a liquid sodium-cooled fast reactor, which will use liquid metal (sodium) as a coolant rather than water. The port authority in Saint John, N.B., is also eyeing the model to support hydrogen production.

The SMR planned for Ontario Power Generation’s Darlington nuclear site is a boiling water reactor. It uses light water (which is normal water, unlike all reactors in Canada, but like most others in the world) so it will need enriched uranium fuel, which will have to come from outside Canada. Saskatchewan has selected the same model with a goal of using it sometime in the 2030s.

Why do we need SMRs?

Canada has vowed to cut its greenhouse gas emissions by at least 40 to 45 per cent below 2005 levels by 2030. According to the federal government, that means we must lower our emissions to between 407 and 445 megatonnes of greenhouse gas pollution. The latest data from 2020 shows we are currently at 672 megatonnes.

Part of reaching our climate goals will be changing our power sources from fossil fuels to clean energy. SMRs don’t release emissions while generating electricity, so they are seen by some as a viable alternative as we shift off coal, oil and gas.

According to the federal government, SMRs could be used to help achieve our climate goal in three ways: by replacing coal plants, powering heavy industry operations in places like the oilsands and remote mines, and providing electricity for remote communities reliant on diesel.

While the fossil fuel industry is touting SMRs as a way to decarbonize Alberta’s tarsands, which typically use fossil fuels to power operations, experts have stressed that oil and gas production needs to wind down if the world is going to reach its climate goals.

An analysis published in Policy Options found that as of 2018, 24 remote mines reliant on diesel were potential candidates for SMRs by 2030. However, the authors concluded the cost of producing an SMR was too high to justify an electricity demand of this magnitude. Rather, wind and solar are more affordable.

The role of SMRs in powering remote, mostly Indigenous communities that now rely on diesel has also been contested. Research has shown SMRs to be one of the least desirable energy options to those communities, who are concerned with being left with nuclear waste and the high costs of SMRs compared to cheaper renewables.

Why are people against SMRs?

Those against SMRs often oppose them for three main reasons:

1. They will be in operation too late to address the climate crisis.

In Canada, the first SMR is supposed to be ready by 2028 for the Darlington Nuclear Generating Station in Ontario. However, some say that goal is unrealistic. An early SMR built by Oregon’s NuScale was originally supposed to generate electricity by 2016, but the completion date has since been pushed to 2029 or 2030. A new report by the Institute for Energy Economics and Financial Analysis described the project as “too late, too expensive, too risky and too uncertain.”

Meanwhile, renewable sources of energy like wind and solar already have technology that is developed and proven.

2. They’re too expensive.

Since SMRs haven’t yet been built, it’s hard to say how much they will ultimately cost, but it’s in the billions. Don Morgan, minister responsible for SaskPower in Saskatchewan, said a small reactor would cost around $5 billion. And the costs of projects underway have often ballooned: the NuScale project went from costing $3.1 billion in 2014 to $6.1 billion in 2020. As a result, the power generated by SMRs is expensive. A 2015 report from the International Energy Agency and the OECD Nuclear Energy Agency found electricity costs from SMRs are predicted to be 50 to 100 per cent higher than typical nuclear reactors.

3. They create harmful nuclear waste.

According to research from Stanford University and the University of British Columbia, SMRs are actually set to produce more nuclear waste than conventional plants. As of now, Canada’s nuclear waste is stored on site at facilities, but all of the locations are designed to be temporary. There is no waste disposal plan for nuclear waste from SMRs, and Canada has been struggling with where to dispose of the nuclear waste already created from existing and past reactors for around a decade. The Canadian Environmental Law Association notes: “SMR wastes will also have higher concentrations of radiation and the SMR designs that claim to ‘burn up’ existing radioactive waste will create new, even more toxic waste streams.”

Who is building SMRs in Canada and how far along are they?

In Canada, the federal government is currently backing SMR technology through its action plan, as are the provinces of Alberta, Ontario, Saskatchewan and New Brunswick, all of which signed a memorandum of understanding expressing support for SMRs.

According to provincial SMR plans, the first one in operation will be at the Darlington nuclear site in Ontario in 2028. Plans are also underway in Alberta and New Brunswick, where ARC Clean Energy is aiming to have an SMR in operation by 2029, and Moltex Energy says its spent fuel recovery system and reactor will come online in the early 2030s. Four more SMRs will follow between 2034 and 2042 in Saskatchewan.

In the plans, they also note another type of SMRs which would be smaller and have less power generation. Rather than supplying grids, they’re designed “primarily to replace the use of diesel in remote communities and mines.” The plan also notes the nuclear research facility at Chalk River, Ont., which is aiming to be in operation by 2026.

Are SMRs viable?

That is the biggest question surrounding SMRs. Although the plans for these next-generation nuclear units might hypothetically work, their viability hasn’t been proven anywhere. Proponents of the tech don’t let that get them down: they say the proposals are strong and are the key to reducing emissions.

But there is no sign that opponents will back down, either. In Canada, numerous Indigenous, scientific, environmental and citizen groups have called the technology a “dirty, dangerous distraction” from real climate action.

[Top: Illustration by Ata Ojani]