Paul van Gerven
15 September

The nuclear menu has expanded with small, modular nuclear power reactors. What do they have to offer?

Nuclear power seemed destined for a life on the sidelines. Its share in the world’s electricity production was already on a steady decline when disaster struck at the Fukushima plant in Japan over a decade ago, prompting countries all over the world to phase out their nuclear power plants. Construction of new facilities often faces hefty delays and massive budget overruns. For example, the Olkiluoto-3 reactor in Finland, scheduled to come online later this year, is twelve years late and 8 billion euros over the original budget of 3 billion, according to the 2019 World Nuclear Industry Report.

Few countries, most prominently China and Russia, are prepared to keep putting up the hefty subsidies needed to continue building new plants. As a result, the 11 percent share of nuclear power in global electricity production in 2020 has been predicted to remain steady at best, or drop to 6 percent in a low-case scenario, according to data from the International Atomic Energy Agency (IAEA). For a low-carbon energy source during a transition away from fossil-based energy sources, that’s not a lot of love.

The IAEA’s prediction was published last year. Today, nuclear’s prospects seem a little brighter. Governments are reconsidering their energy policies now that the Russian invasion of Ukraine has sent natural gas prices through the roof. Offering a measure of energy security along with low-carbon electricity, nuclear energy suddenly doesn’t seem all that bad anymore.

Even more so because the menu has expanded to bite-sized nuclear power. An impressive number of companies are touting Small Modular Reactors (SMRs), which are cheaper to build and therefore mitigate the financial risks associated with large-scale plants such as the Olkiluoto-3, while also offering better safety. Is a new nuclear dawn nigh?


SMR is an umbrella term for dozens of different designs that produce less than 300 megawatts of electricity. For comparison, the Olkiluoto-3 has a nameplate capacity of 1,600 megawatts. The distinguishing feature of SMRs is that they’re small enough to be ‘mass-produced’: the components are manufactured in a factory and assembled on-site. SMR’s safety systems are typically fully passive, meaning they don’t need an external power source to function, not even when an accident has happened. They also don’t require human operators.

Worldwide, about 65 SMR concepts are being developed. Just recently, the US Nuclear Regulatory Commission certified the design of SMR hopeful Nuscale Power, clearing a huge hurdle toward commercial application. Bill Gates-funded Terrapower and GE Hitachi Nuclear Energy announced a sodium-cooled demonstrator reactor in Wyoming. Over in Europe, the Urenco consortium is working on a design created by Delft University of Technology and Manchester University.

China has started construction of its first commercial SMR, which will eventually provide power to the tropical island Hainan. The world’s first operational small reactor is found in remote Siberia, though the floating power barge isn’t considered a true SMR, since the reactor is adapted from technology already found on nuclear icebreakers.


If not for their more agreeable price tags, proponents say that SMRs need to be in the low-carbon energy mix the world is moving towards, because they can be built quickly and there’s a lot of lost ground to make up for. Additionally, the output of SMRs can be throttled more easily than that of traditional plants, making them good choices to handle the variable nature of solar and wind power.

Critics, however, say SMRs don’t do anything to solve nuclear energy’s waste problem. In fact, Stanford-led research found that SMRs increase the volume of nuclear waste in need of management and disposal by a factor of 2-30. No country has a permanent solution for how to safely store this kind of waste, though some countries are building deep geological repositories.

Opponents aren’t convinced by the purported economic benefits either, which rely on modularity and factory manufacture to compensate for the loss of scale. Even with an optimistic learning curve, many hundreds or even thousands of SMRs would have to be created for their bang for the buck (price per megawatt) to match conventional nuclear power – which is already one of the costliest forms of energy. Who will buy those ‘overpriced’ SMRs?

One way to make SMR technology more competitive would be for countries to pool their resources and come up with a standardized design. Since the fate of SMRs is already in the hands of policymakers and politicians rather than market forces, that might be the best way forward.