Terra Innovatum Global, a developer of micro-modular reactors (MMRs) has signed an agreement with Italy-based ATB Riva Calzoni, a global supplier and manufacturer of nuclear components, to initiate early industrial production activities for its SOLO reactor. This follows a memorandum of understanding signed in September.
The agreement outlines a phased collaboration that will:
- validate and refine key component manufacturing parameters to ensure optimized production for SOLO’s commercialisation phase;
- develop, test, and streamline assembly processes for the first-of-a-kind (FOAK) unit, with a focus on scalable, repeatable manufacturing;
- design factory-level logistics for efficient material handling and just-in-time component availability during assembly; and
- evaluate transportation logistics and constraints associated with reactor delivery and deployment.
SOLO can easily scale up to deliver 1 GWe or more with a minimal footprint, making it suitable for rapidly replacing fossil fuel-based thermal plants. As well as electricity and heat generation, it can also contribute to critical applications in the medical sector by producing radioisotopes essential for oncology research and cancer treatment.
SOLO is a 4 MWe/20 MWt micro-modular reactor (MMR) designed for applications such as off-grid military complexes. It was conceptualised in 2018 and the design was developed over six years. Terra Innovatum anticipates that SOLO will be available globally within the next three years.
SOLO features a thermally-moderated, helium-cooled nuclear reactor. The design features a “solid heterogeneous composite moderator” and is intended to accommodate both traditional zircaloy-clad low-enriched (below 5%) uranium (LEU) fuel or, when available, LEU+ and high-assay low-enriched uranium (HALEU) fuels. The reactor’s design efficiently decouples cooling and moderation functions, providing inherent safety features that significantly reduce its risk profile. This enables a straightforward safety analysis, where the safety case can be established based on fundamental principles, without the need for complex evaluation models.
The reactor features autonomous operation, on-line safeguards-by-design, and a defence-in-depth structure of radiological barriers aimed at to minimising or eliminating emergency planning zone (EPZ) requirements beyond the operational boundary. SOLO is intended to form the basis for a scalable modular energy platform from MWe to GWe-class. Terra Innovatum says it will be built from readily available commercial off-the-shelf components simplifying the licensing path to enable rapid deployment, minimising supply chain risks, and ensuring final cost predictability.
Terra Innovatum says SOLO is designed to offer a wide range of versatile applications, including off-grid power solutions for data centres, mini-grids serving remote towns and villages, and large-scale industrial operations. It can also supply heat for industrial applications and other specialised processes. The US Nuclear Regulatory Commission (NRC) has been engaged in pre-application activities with Terra Innovatum since January 2025, according to the company website.
Alessandro Petruzzi, Co-Founder & CEO of Terra Innovatum, said the agreement with ATB Riva Calzoni, “marks a key milestone in establishing Terra Innovatum’s outsourced manufacturing model”. He added: “By leveraging ATB’s facilities, equipment, and proven expertise, we will produce our first SOLO reactor while completing the licensing process in the US for its deployment. Under this agreement, dedicated SOLO assembly lines will be created using standardised, repeatable processes, making reactor production predictable, scalable, and highly cost-efficient.”
According to Giordano Morichi, Terra Innovatum Partner and Chief Business Development Officer & Investor Relations: “Partnering with ATB Riva Calzoni de-risks our commercialisation by bridging the gap between investment and production, while mitigating the cost and schedule uncertainties that have long challenged nuclear projects. The compact, modular SOLO reactor is designed for lean, factory-based manufacturing and rapid on-site assembly—turning what once took years into months.”
Francesco Squaratti, Managing Director of ATB Riva Calzoni said: “We see Terra Innovatum as a long-term strategic partner with whom we can establish a new global standard for microreactor manufacturing. With decades of experience building advanced components and systems for leading players in the nuclear industry worldwide, we are proud to bring our expertise to the next generation of clean energy. Together, through the SOLO program, we aim to usher in a new era of scalable, safe, and efficient microreactor solutions.”
