The UK government has unveiled plans to establish over a dozen small reactors nationwide, marking a new era for nuclear energy. A key objective is to help the country eliminate reliance on Russian energy within three years. But can a small reactor achieve both engineering feasibility and commercial success?

Before visiting London on September 16th, the US President and UK officials announced a partnership between Centrica and US startup X-Energy to build 12 small modular reactors in energy data centers, alongside a “micromodular nuclear power plant” developed by Last Energy at DP World’s London Gateway Port.

However, no timelines for commencing these projects were provided, and the Ministry of Energy Security and Net Zero did not respond to New Scientist‘s request for clarification.

This initiative aligns with the trend toward smaller reactors. According to Bruno Merck from the University of Liverpool, Rosatom, the Russian state nuclear agency, has recently completed a small nuclear reactor designed for use in nuclear-powered icebreaker ships. Notably, they continue to construct more reactors, suggesting either a demand for these devices or a commercial demonstration aimed at securing future sales despite ongoing sanctions post-Ukraine invasion.

China has also developed the Linglong One small reactor, though its commercial viability remains uncertain. Major tech companies like Amazon, Google, and Microsoft are investing heavily in these types of nuclear technologies.

David Dye from Imperial College London remarks that while small reactors are appropriate for remote military bases and Arctic locations, there is skepticism about their applicability for the needs of tech giants. He suggests that it’s considerably simpler to locate a data center next to a power source.

“For tech visionaries with significant financial resources, investing $50 million in such technology seems trivial,” Dye notes, pointing to the wealth of influential individuals in this field.

One potential motivation, indicates Michael Bluck from Imperial College, is reliability. “Data centers must operate 99.995% of the time,” Bluck explains. “Securing that electricity means having first access to it.”

Bluck asserts that there are no engineering or scientific barriers preventing the swift construction of small reactors. He highlights that many small experimental reactors function in universities and military submarines globally.

“It’s not about size. It’s about modularity, production line construction, and standardized components, which represent practical and sound engineering practices,” Bluck states.

However, the miniaturization of nuclear reactors does come with several drawbacks. Merck explains that scaling up usually yields greater efficiency in terms of cost and energy. Both large and small reactors require similarly thick concrete shielding, which adds safety considerations. Furthermore, while larger reactors achieve a better volume-to-surface area ratio, smaller reactors encounter challenges in neutron fission chain reactions, resulting in less energy production from the same fuel quantity.

“It’s just physics,” Merck states. “Anyone suggesting otherwise is probably mistaken. I don’t subscribe to magical thinking.”

That said, Merck highlights that traditional nuclear power facilities require years of planning, substantial political will for funding, and extensive resources for operations. “These facilities are costly to build,” he adds. “Smaller reactors may offer a more feasible alternative.”

Innovative Nuclear Designs

Bluck notes that the recent governmental announcement features two distinct designs. X-Energy is focusing on the XE-100, while Last Energy is using a relatively conventional pressurized water reactor known as PWR-20, which operates on similar fuel as the Sizewell B nuclear facility in the UK. The former may represent a longer-term vision, but the latter could achieve market readiness sooner.

Nevertheless, even with established fuels and technologies, Bluck estimates a minimum five-year timeline before a prototype reactor can be constructed in the UK. “Everyone desires results immediately,” he remarks, “but they must understand that energy development takes time.”

For plans to mass-produce and export these small reactors, obtaining regulatory approval is crucial, and this process will need to start from square one in the host countries.

Bluck suggests this is significant for US and UK announcements. The agreement aims to accelerate approvals across jurisdictions, allowing for cross-border sign-offs. For instance, Rolls Royce is working on a small modular reactor that is considerably larger than those proposed by US startups, resembling traditional power plants. If it gains UK approval, it could quickly enter the US market.

Despite this, Bluck cautions that the initiative carries inherent political risks. “For those against nuclear energy, questions will arise regarding trust, asking, ‘Are we simply accepting what’s offered?'” This partnership aims to alleviate some of those concerns. “We acknowledge the issue, and this is the first time two major manufacturing nations have come together in this regard,” he concludes.