Nuclear power remains a contested subject. For decades, rejected bills and referendums that ended in a “No” vote blocked large plants in Italy. But that does not mean everything has stood still — quite the opposite. A new generation of nuclear reactors is growing quietly and aims to overhaul the entire global energy sector: SMRs.
In a context where data centers demand ever more power for artificial intelligence, giants like Amazon, Google and Meta are preparing to invest billions in this nuclear source. So much so that several projects are already under construction in the United States and China.
But what exactly are they, and what would the immediate advantages be? In this guide we explain what SMRs are, who has already invested, where they could go, and whether there is an opening for Italy too.
What are SMRs
SMRs (small modular reactors) are nuclear reactors rated at up to 300 MWe, built with modular technologies that rely on prefabrication. Unlike traditional reactors that exceed a thousand megawatts, SMRs operate at far lower power and were designed to be standardized, easily repeatable production units.
The key to understanding them is the word modular. A plant based on this technology does not house a single large reactor but several identical modules. It is the same logic as a car assembly line: standard components, uniform quality controls, reduced build time and, above all, lower costs.
Today there are two main categories of SMR. The first uses a Gen III+ design and is based on established technologies such as pressurized water reactors. Then there are Gen IV+ designs that use alternative coolants such as sodium and molten salts.
How SMRs work
Like any other nuclear reactor, SMRs harness nuclear fission. Heat is generated to boil water, make steam, and spin a turbine and a generator, producing electricity in a thermal power station. The big difference lies in scale and operational flexibility.
One clear advantage of SMRs is the ability to carry out maintenance — refueling and inspections — at the module level. This way, only small increments of energy production are interrupted, rather than shutting down the entire plant.
So if a single module needs to be checked, the others can keep running and generating power without stopping.
What SMRs are for
With electricity demand from data centers projected to reach 1,300 TWh globally by 2035, the use of SMRs could become essential. It is no coincidence that the four largest American big-tech companies collectively signed for more than 10 GW of new nuclear capacity last year.
Renewables exist and are growing, but they may not be enough. That is because they work intermittently, require large amounts of land, and must be built across vast areas. Nuclear, by contrast, offers stable, dispatchable power that runs around the clock.
These are also systems that can be used either as a single plant or as a cluster of modules, offering the option of combining nuclear with alternative sources (including renewables). They can power steel mills, refineries, remote communities, islands and military bases, for example.
But the focus remains squarely on AI data centers and other industrial activities where developers may not want to connect to the grid.
The advantages of SMRs
Several factors could push SMRs toward large-scale adoption. First, given their small size and the high level of technology involved, they are considered safer than traditional reactors. With lower thermal output, residual heat is dissipated more easily, even without external power.
Another major advantage over traditional plants lies in a shift in the underlying economics. Instead of achieving economies of scale through the size of a single plant, they achieve them through production volume. Whereas a large traditional reactor requires 10 to 15 years of construction, with all the variations and cost overruns that entails, SMRs are built in a factory to industrial standards and then transported to the chosen site.
In terms of sustainability, SMRs offer the best cost profile and are suited to cogeneration. These are systems that supply heat and power to decarbonize heavy industry. In short, they are small modular reactors that, in a short time, can help provide stable energy to power-hungry sectors such as industry and data centers themselves.
Are there active SMRs already?
The whole world is starting to move toward SMR systems. Beginning with Romania, where a 462 MWe plant by NuScale Power is in development — the first SMR with a design certified by the NRC (the U.S. Nuclear Regulatory Commission).
In the United Kingdom, Rolls-Royce recently obtained GDA Step 3 (the Generic Design Assessment, Britain’s regulatory review process), with the Wylfa site already selected. Construction is expected to begin in 2027. X-energy, meanwhile, is signing partnerships with Amazon and Korea Hydro & Nuclear Power to assess the possibility of powering AI data centers with nuclear energy.
And in Italy? For now, some private alliances have been set up, such as the one between Maire and Newcleo to develop plants based on a 200 MWe advanced modular reactor. Edison has signed an agreement with EDF (Électricité de France) and ENEA, the Italian national agency for new technologies and energy, to study the potential deployment of SMRs in support of Italian industry.
The outlook for SMRs
Today, the global SMR market is estimated to reach $53.8 billion in value by 2036, surpassing $300 billion by 2046 (source: IDTechEx).
A boom that, if it materializes, would be driven by three main factors. First, exponentially rising energy demand because of AI; then geopolitical pressure for energy autonomy; and finally, climate urgency.
While private investment currently comes almost entirely from tech giants, governments are beginning to lend their support through public funding and regulatory streamlining.
There are, however, still open challenges. SMRs are at the prototype stage and commercialization is expected after 2030. One key issue is regulatory approval, although important progress has been made recently.
Questions remain, above all, on nuclear waste management and the fuel cycle, even if advanced SMR designs appear to promise closed, more sustainable cycles.
Editor’s note
This article was originally published in Italian on money.it by Pasquale Conte on June 21, 2026 as «Cosa sono gli SMR, i piccoli reattori nucleari che accendono il futuro dell’AI?». It has been translated and adapted for an international audience by the Money.it International desk.
