Italy-based nuclear start-up Terra Innovatum Global has executed a critical procurement agreement with Howden Turbo GmbH, a division of Chart Industries, to supply steam turbines and power generators for its SOLO micro-modular nuclear reactor platform. The multi-year supply agreement stabilises the company’s hardware pipeline, moving its modular architecture closer to active production.
The SOLO Micro-Modular Reactor (MMR) is a 1 MWe (5 MWt) high-temperature, gas-cooled reactor (HTGR) designed for autonomous, off-grid operation. Its primary technological innovation is a “rule of precedent” approach, utilising commercially available, pre-licensed components to bypass typical regulatory delays. It uses helium gas as a coolant and a solid heterogeneous composite moderator.
It is designed to use standard low-enriched uranium (LEU) UO2 pellets in Zircaloy cladding but is future-proofed to accept LEU+ and HALEU fuels when they become commercially available. It can operate for 15 years without refuelling (extendable to 45 years via core swap) and fits in a standard 40ft shipping container. Its 2.5-metre-thick concrete biological shield reduces the radiation dose to below public limits, eliminating the need for a large emergency planning zone.
The agreement secures a long-term supply of critical secondary-side equipment for Terra Innovatum’s First-of-a-Kind (“FOAK”) SOLO reactor, targeted for deployment in Illinois by 2027, and supports subsequent Nth-of-a-Kind (NOAK) global commercialisation. Terra Innovatum has already selected its FOAK site at Rock City Admiral Parkway Development in Illinois and has entered into non-binding MOUs for up to 100 SOLO units worldwide.
Through this collaboration, Terra Innovatum and Howden have adapted and optimised Howden’s proven steam turbine technology to meet the specific requirements of the SOLO reactor. The work aligns performance, efficiency, and modular integration to support standardised deployment across sites. It leverages Terra Innovatum’s “fabless” supply chain model, which uses established nuclear manufacturers rather than new in‑house facilities, to accelerate industrialisation. “Fabless” (combining “fabrication” (manufacturing) and “less” (without), describes a business model where a company designs and brands its products but outsources 100% of the physical manufacturing to third-party factories.
Under its fabless manufacturing model, Terra Innovatum has condensed its core network from 130 potential vendors to 30 contracted partners to secure the safety-critical, nuclear-grade components of the SOLO platform. Key tier-one suppliers handling the radioactive core, containment, and immediate thermal management systems include:
- ATB Riva Calzoni (Nuclear Vessels & Infrastructure) – primary early industrial production and manufacturing partner. ATB Riva Calzoni supplies the reactor pressure vessels, structural components, and factory-level assembly logistics.
- Conuar (Fuel Elements & Reactor Cooling Internals) – strategic Argentinean nuclear systems and fuel components specialist. Conuar manufactures critical fuel components, zirconium alloy parts, and reactor cooling tubes.
- Mersen (Nuclear-Grade Graphite Core) – France-based specialised industrial materials supplier. Mersen secured the long-lead first procurement order for nuclear-grade graphite blocks.
- Established commercial fuel suppliers. Rather than developing custom fuel configurations, Terra Innovatum relies on existing licensed fuel facilities to supply standard low-enriched uranium (LEU) fuel types that have been commercially scaled and regulatory-approved for over 60 years. The platform is forward-compatible with emerging LEU+ and HALEU formats.
- Specialised engineering & testing network. Italy-based Boldrocchi delivers the specialised high-pressure helium circulators needed to test and move heat through the gas-cooled core. US-based Paragon Energy and TechSource provide supporting nuclear engineering, safety verification, and instrumentation architectures
The partnership with Howden also supports flexible system architectures by integrating multiple SOLO units with a common Howden turbine platform to deliver scalable output from 3 to 15 MWe, suitable for applications from data centres and industrial facilities to remote mini‑grids. Together, these efforts are intended to shorten deployment timelines and lower lifecycle cost through repeatable, standardised production, supporting Terra Innovatum’s goal of FOAK deployment in 2027 and broader commercialisation beginning in 2028. Terra Innovatum anticipates that SOLO, conceptualised in 2018 and engineered over six years, will be available globally within the next three years.
“Strategically aligning with Howden gives us access to a proven track record and decades of deep expertise in steam turbine technology, particularly in the power range suited for SOLO.” said Marco Cherubini, Co-Founder and Chief Technology Officer of Terra Innovatum. “Their reliability and engineering experience significantly de-risk both our FOAK deployment and long-term NOAK scaling.”
Volker Brakel, Head of Steam Turbines at Howden, noted: “Terra Innovatum’s SOLO concept stands out for its rapid path to market and strong scalability. Its modular architecture and ability to combine multiple units enable flexible power solutions while providing the deployment visibility needed to plan production and build a robust industrial roadmap. A deployable micro-modular reactor with clear market timing creates a strong foundation for long-term growth and collaboration.”
