A power plant so small that you can go around it, but so powerful that it provides energy for years on end, silently and without local emissions. Not a utopia, but a concrete concept: micro-reactors (micro-modular reactors) are opening a new frontier for the energy of the future.

What is a nuclear micro-reactor?

These devices employ state-of-the-art nuclear technologies in a small size. Typically, their power is around 1 megawatt electric (MWe), but they can be aggregated into scalable systems ranging from megawatts to gigawatts. Their modularity allows them to be mass-produced, installed where needed and operate autonomously, with minimal maintenance and advanced safety standards.

Some designs run on helium as a cooling fluid — safe, stable, and ideal for eliminating water dependency in traditional systems. Their robustness and reliability also make them suitable for remote or isolated environments: from military bases to islands, data centers or energy-vulnerable communities.

And the dross? A manageable problem, but not negligible

One of the main concerns related to nuclear energy concerns the management of radioactive waste. Even in the case of micro-reactors, although they produce much smaller quantities than traditional power plants, the problem does not disappear. The waste generated – in particular, spent fuel – requires safe storage for very long times, although some new generation technologies, such as breeder reactors or lead-cooled reactors, aim to recycle part of the fuel, significantly reducing the volume and hazardousness of waste. In Italy, the issue is even more delicate: the national repository for radioactive waste has not yet been built, and there remains a knot to be untied for any possible revival of the atom, whether micro or large. However, the small size of modular reactors also facilitates the logistics of waste, which could be transported and treated centrally in a more efficient and traceable way.

Italy and micro-reactors: new openings

After almost forty years of denuclearization, Italy is preparing to write a new chapter: a strategy is emerging to reintroduce nuclear production, not so much for large power plants, but for advanced modules such as SMRs and AMRs.

In addition, the establishment of Nuclitalia, an alliance between Enel, Leonardo, and Ansaldo Energia, with the aim of leading research on next-generation modular reactors, has recently been established.

Italy does not look only to the mainland. Thanks to an agreement between ENEA and the Italian Space Agency (ASI), a study is underway on micro-reactors designed to power lunar bases or stations in deep space, where solar energy is difficult to obtain and continuity is vital.

Perspectives and areas of use

Compact micro-nuclear reactors promise silent revolutions:

• Clean and on-demand energy, where renewables are not enough or do not arrive.
• Always-on urban data centers, without depending on congested networks.
• Energy autonomy in construction sites, mines, or isolated communities, reducing emissions and logistics costs.

Despite the advantages, there are still unresolved issues. SMRs, which are larger than micro-reactors, are expected to be available by 2030 in Europe — but only at pilot level. Some companies already active, such as Ultra Safe Nuclear Corporation, have encountered financial difficulties in transforming the experimentation into real plants on the Italian territory.

Sources and insights

• Terra Innovatum Introduces ONLY Micro-Reactor (1 MWe) — World Nuclear News. Link
• U.S. Partnership to Commercialize SOLO Micro-Reactor — World Nuclear News. Link
• Micro-reactors for data centers in smart cities — CERIDAP. Link
• Italy towards the reintroduction of nuclear power with micro-reactors — Reuters. Link
• Nuclitalia: advanced nuclear research in Italy — Reuters. Link
• Italy and the return to the atom as a complement to renewables — Le Monde. Link
• Micro-reactors for space energy: ENEA-ASI AGREEMENT — ENEA / Euronuclear. Link