Small modular reactors: How the next wave of nuclear power can fuel the energy transition
November 29, 2022
Compact nuclear reactors can potentially provide us with safe and reliable energy generation
The impacts of climate change are driving global efforts to reduce greenhouse gas (GHG) emissions by humans transitioning away from fossil fuels and toward clean energy sources. From solar power to hydropower to wind power, the energy transition will require an all-in approach to meet the needs of communities around the world.
The move away from fossil fuels must focus on both the source of energy and its reliability. After all, with the increasing adoption of electric vehicles and electrification generally, energy demands aren’t going down anytime soon. Based on publicly available data produced by many notable observers—such as the World Energy Outlook, Our World in Data, and others—our thirst for energy is only set to increase at alarming rates.
Renewable energy sources like wind and solar are great green options for reducing emissions. But they aren’t as reliable as traditional sources like coal or natural gas. So, how can we decarbonize while providing a strong source of sustainable, uninterrupted, and economically viable energy? Nuclear power-based generation could be a solution.
Nuclear power can supply reliable energy and has a much smaller carbon footprint than traditional fossil fuels. In fact, NASA researchers believe that nuclear power eliminated an average of 64 gigatons of CO₂-equivalent net GHG emissions globally from 1971 to 2009. Nuclear power has the potential to reduce our reliance on fossil fuels.
Traditionally, nuclear power has faced criticism for being expensive, unsafe, or damaging to the environment. But in recent years, nuclear power generation has made several advancements in safety, security, technology, reliability, affordability, and adaptability. These improvements have led to the advancement of small modular reactors (SMRs)—as opposed to large-scale plants—as an attractive alternative.
SMRs could be the missing piece of the clean energy puzzle. Let’s dig into SMR technology and how it can help us navigate the energy transition.
So, what exactly is an SMR?
SMRs are what they sound like: compact, standardized-design, small-scale reactors. SMR technology providers report that compared to a large conventional nuclear power station with its big containment structures and cooling towers, SMRs have a much smaller footprint and they are far less complex with fewer mechanical components. They also have much less of an environmental impact in fabrication, construction, and operation. Although the technology is far simpler than traditional reactors, SMRs use a similar process of fission to split atoms (likely of uranium or plutonium) to release thermal energy. Basically, it uses heat to generate steam that spins turbines and produces electricity.
The size of SMRs can vary, with some SMRs having a power capacity of up to 300 megawatts (MW) per unit. Smaller units—known as micro modular nuclear reactors—start at the size of a typical stacked washer/dryer and can provide up to 25 MW. They also may work in an off-grid or microgrid setting. That compares to a conventional nuclear power plant unit, which has a capacity of 580 MW to more than 1,000 MW.
If we want to reduce our dependence on fossil fuels, SMRs should be part of the discussion.
Traditionally, energy providers (utilities) built large nuclear power-generation facilities on site in remote locations and distributed the electricity over great distances to the grid via transmission lines. SMRs reverse that approach.
Unlike traditional nuclear reactors, which are mostly enormous custom designs built on site, SMR manufacture is light, nimble, and repeatable. It’s much like a car assembly line. Providers can fabricate and pre-commission SMRs at an assembly plant and deliver them by traditional semitrucks to the operational site with minimal impact on transportation corridors. They place them on prefabricated foundations, plug them in, and make them operational in a fraction of the time it takes to commission larger units.
When most people visualize nuclear power plants, the image includes their massive cooling towers. SMRs have a smaller footprint, minimal staffing requirements, and a modern look. They will look more like small warehouses or industrial buildings you see along the roadside. There are no cooling towers.
Whether they are servicing industrial or other large facilities with large energy requirements or connecting to a microgrid or power utilities, SMRs will be housed in buildings. SMR facilities will also require support buildings for offices, maintenance, and training, as well as water supply/treatment plants for intake and discharge.
With the much smaller footprint, these SMRs can be installed in locations much closer to where the power is needed. This can potentially eliminate or reduce the need for long high-voltage transmission lines, providing less visual impact as well.
Traditional nuclear power plants can take years—even decades—to plan, build, and certify. SMRs have the potential to be constructed and operational in months. But while the industry is making strides, it’s still too early to determine how long SMR certification will take.
Cumulative CO₂ emissions (gigatons) avoided by nuclear power by country or region, 1990-2020. (EMDES = emerging markets and developing economies) (Source: IEA.ORG)
What role do SMRs fill in our energy infrastructure?
Much like a conventional nuclear power plant—or even a coal-fired powerplant—SMRs provide consistent and reliable power at a scale compatible with local needs. While solar panels only generate power during the day, SMRs can run 24/7 and provide energy anytime there is a need for it.
Another benefit to SMRs being modular is the ability to increase power supply as local needs grow. Because they are modular (and the assembly process is repeatable), it’s relatively easy to add more SMRs when needed. This not only creates a more resilient energy supply but it also allows smaller energy providers to start with a few SMRs and increase incrementally.
Potential customers for SMR technology include power utilities, municipal governments, universities, research and health care campuses, off-grid remote communities, and power-intensive industries. SMRs can be incorporated into microgrids and distributed generation systems, by owners and end users alike. Utility providers or communities can slot SMRs into brownfield sites in place of decommissioned coal-fired and natural gas-fired plants—decommissioning fossil-fueled plants is a key part of the energy transition.
Vendors also envision SMRs use in non-electric applications such as district heating, water desalination, greenhouse heating, and hydrogen fuel production.
A typical SMR could be housed in a vertical containment vessel. Small light water reactors (SLWR) are likely to be among the first SMRs that come online. In the reactor core, the SLWR splits atoms in a fission reaction, creating a chain reaction, releasing energy as heat. The SLWR passes water over a series of uranium fuel rods. Generators use the heat from the water to produce superheated steam which drives a turbine to generate electricity.
What are the barriers to adoption?
No one has yet deployed SMRs for commercial energy generation. However, SMRs have been used by nuclear-powered navies for decades. There are several SMR pilot projects underway in the US, Europe, and Russia. And there are currently several SMR vendors seeking certification for their designs from Canadian and US nuclear agencies. It’s likely the first commercial SMRs will come online in Canada and the US between 2028 and 2030.
Nuclear power has had no shortage of critics over the years. Disasters like Chernobyl and Fukushima certainly had an impact on the public perception of these kinds of plants—and for good reason as those events showed how serious incidents can be if a failure occurs. SMRs are far simpler in mechanical design, which means they have fewer components that could potentially fail. The Canadian Nuclear Safety Commission is requiring SMR technology providers to design passive safety systems into SMRs. Their small size makes passive safety systems much more easily implemented and effective. A passive safety system incorporates safety mechanisms that act in the event of a problem and do so automatically without any human intervention. Clearly, SMR projects will need to prove how the facility is safe and will require strict safeguards for operations.
But the public also wants to know if SMRs will be environmentally friendly. Reducing carbon emissions is great. But what impact will these facilities have on the surrounding environment, and how will they dispose of the waste and keep it secure? SMR vendors and operators will need to address questions about spent fuel management to the satisfaction of the public and regulators. Although some SMR technologies recycle the fuel cells a number of times (thereby reducing the radioactive content of the spent fuel), the extraction, loading, transportation, and eventual storing of radioactive waste is a key focus area actively being researched. SMRs have a small footprint—even smaller than renewables such as wind and solar. They can fit inside and/or replace traditional coal, diesel, and natural gas plants, reusing existing land.
Another concern that critics have with nuclear power is the cost. And to be fair, traditional large-scale nuclear plants are massive endeavors that require significant investment in both time and money. The simplified design of SMRs will allow manufacturers to make SMRs at scale. This gives SMR providers repeatability in build, materials, testing, quality assurance, and assembly—reducing the cost to manufacture and assemble SMRs on site. This means manufacturers can bring them to market quicker than traditional nuclear power stations and users can spend less on capital investment and maintenance as compared to a traditional nuclear reactor. If vendors can scale up their SMR production, SMRs will become even more affordable.
Are SMRs a key to the energy transition?
The impacts of climate change have made it clear that we must work together to reduce carbon emissions. But society also needs energy. These two realities must coexist if we want to make the planet better for future generations. Nuclear power can work hand-in-hand with renewable sources to meet our low carbon energy needs. We may see coupling SMRs with other renewable sources, where the SMR provides the base energy load and renewables such as wind and solar supply the peaking energy. If we want to reduce our dependence on fossil fuels, SMRs should be part of the discussion.
The recent advancements of SMRs should be an encouraging development for the energy and resources industry. The promise they offer includes a small footprint, easy installation, cost-effectiveness, environmentally friendly, and a simpler design compared with traditional large-scale nuclear plants. In time, SMRs will undergo even more technological advancements. And that should make them an even more enticing option.
We eagerly await the arrival of SMRs as a safe and reliable option in transition to a clean energy production future.