Nuclear Small Modular Reactors (SMRs) aim to disrupt the nuclear industry, slashing the cost of nuclear energy to competitiveness with renewables + storage and making new decarbonisation-enabling uses of nuclear power possible, writes Sam Dale, technology analyst at IDTechEx.

In 2023, SMRs are operational in China and Russia, with the rest of the world looking to catch up. Elsewhere, a startup designed SMR could be the first to enter operation. Still, the question remains: in the emerging SMR market, will the agility of new players beat the embedded positions of the nuclear industry’s existing giants?

IDTechEx’s report, 'Nuclear Small Modular Reactors (SMRs) 2023-2043', predicts that 25% of nuclear-sourced electricity will come from SMRs in 2043, compared to a negligible percentage today.

The diversity of designs this rapid scale-up would breed is likely to involve a wide variety of organisations: IDTechEx surveyed 83 SMR projects from many different players. Startups form a high percentage of the organisations involved in SMR development – taking a startup as a firm founded with the express aim of commercialising SMR technology. 

Evolution or revolution?

The nuclear industry is famously conservative, with today’s third-generation reactors evolutions of the earliest designs. The smaller size of SMRs and the new use cases for nuclear energy they seek to serve offer opportunities for innovative startups to provide differentiation, whether in developing a design evolution or working with newer fourth-generation reactor architectures.

One early-stage player building on proven technology is NuScale Power, which as the first SMR company to receive Standard Design Approval from the US nuclear regulator (albeit for an earlier version of its design), is a frontrunner to build an SMR in the US.

NuScale shrinks PWRs (Pressurised Water Reactors), using six of them with a combined electrical capacity of 462MW in its VOYGR-6 design. The small size allows the integration of all the primary steam cycle components into the reactor pressure vessel, helping to reduce on-site assembly costs.

Passive circulation of coolant is possible without the need for pumps, and decay heat can be removed passively in case of reactor shutdown by a water bath surrounding the reactors.

Enhance safety of the design

Both features help enhance the safety of the design and are made possible by the smaller reactor size. Variations on the integral PWR design are the most common approach to SMRs, given that they build on the safety of PWR technology, which forms the bulk of today’s commercial nuclear reactor fleet. NuScale expects its first plant to be operational by the end of the decade.

Some players are pursuing a more revolutionary approach with fourth-generation reactor types. One example is the Canadian firm Terrestrial Energy. Its ISMR400 molten salt reactor (MSR) takes advantage of the high coolant temperature of MSRs to decarbonise industrial process heat while supplying power to the grid.

Due to their lower operating temperatures, the light water-cooled reactors that dominate today cannot directly supply heat to a wide range of industries (eg, petrochemicals). This higher temperature does not imply a safety penalty: since the fuel is already molten in the coolant salt, core melts are effectively impossible, and low operating pressures reduce the risk of coolant leaks.

Of course, newer entrants face significant competition from established players. Nuclear industry giants like GE-Hitachi and Westinghouse Nuclear have their own SMR designs at a high stage of readiness, with the distinct advantages of being able to build on pre-existing large nuclear reactors designs and established supply chains.

While it seems assured these big names will be significant contributors to the global SMR fleet, it looks like there is significant space for new players to make their marks as well, with lower single project costs in the range of $1 billion, as opposed to often tens of billions for a large nuclear plant, making the space more accessible for the next generation of nuclear firms.

IDTechEx’s report 'Nuclear Small Modular Reactors (SMRs) 2023-2043' can be accessed here.