Italy-based nuclear start-up Terra Innovatum (TI) reported that it has secured all key components of its SOLO reactor unit and has completed supply-chain alignment for both critical nuclear-grade and non-nuclear-grade components and systems. TI said this derisks manufacturing and construction timelines while ensuring future deployment readiness. All components have been aligned with vendors qualified to meet the strictest nuclear and industrial performance requirements.
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. I can operate for15 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.
“In advanced nuclear, supply-chain readiness is where serious programs separate themselves from concepts,” said Alessandro Petruzzi, TI Co-Founder & CEO. “By securing both nuclear-grade and non-nuclear components and systems at this stage, we are demonstrating that SOLO is engineered, industrialised and ready to be built.”
Terra Innovatum said it has secured supply pathways for the following safety-critical, nuclear-grade components: fuel, control and shutdown mechanisms, graphite, pressure vessel, isolation valves, reactor cooling tubes, core support structure, instrumentation & controls. engineering, procurement and construction (EPC) contractor.
TI has also secured supply arrangements for non-nuclear-grade but mission-critical primary and secondary systems, ensuring full plant-level integration and execution continuity. These include helium circulator, turbine, steam generator, primary and secondary piping, condenser, pumps and instrumentation & controls.
“Our progress across both the nuclear and non-nuclear supply chain reflects disciplined engineering and a design philosophy centred on execution and on exploiting consolidated R&D and past experience”, said Marco Cherubini, Co-Founder, Chief Technology Officer & Product Director. “This momentum strengthens our path toward commercialisation and reinforces Terra Innovatum’s role in producing and delivering the next generation of scalable, reliable energy solutions.”
TI said its supply-chain readiness positions the company ahead of much of the advanced-reactor field, where unresolved component sourcing remains a key development bottleneck.
Terra Innovatum was originally organised in Italy in 2018 and recently shifted its primary operational and financial focus to the US to accelerate commercialisation and regulatory approval. The SOLO reactor was conceptualised in 2018 following extensive research into nuclear safety at Pennsylvania State University and the University of Pisa.
In October 2025, the company went public on the Nasdaq under the ticker NKLR following a merger with GSR III Acquisition Corp, a Special Purpose Acquisition Company (SPAC). This provided approximately $42.5m in equity The company is actively engaged in the pre-application phase with the US Nuclear Regulatory Commission (NRC). It expects to submit a construction permit application in 2026, with a goal of commercialisation by 2028. Its first commercial deployment is planned for Rock City in Valmeyer, Illinois, where the reactor will provide power to local businesses.
Earlier in February TI announced completion of the Phenomena Identification and Ranking Table (PIRT) for its SOLO microreactor. Completion of the PIRT formally signals that the SOLO microreactor’s technical design is mature enough for rigorous safety evaluation by NRC.
Cesare Frepoli – Co-Founder, COO & Licensing Director stated: “This milestone reflects our disciplined, risk-informed licensing strategy and our commitment to technical rigor from the earliest stages of design. By applying a transparent, NRC-aligned PIRT process, we are ensuring that safety-significant phenomena are identified and addressed in a manner that supports efficient, predictable regulatory engagement. Submission of the PIRT technical report to the NRC in February represents an important step in Terra Innovatum’s broader US licensing strategy for the SOLO™ microreactor, supporting both first-of-a-kind deployment and a scalable framework for future applications.”
Alessandro Petruzzi – Co-Founder & CEO continued: “The PIRT process is a structured, expert-driven approach used to identify and rank the physical phenomena most important to reactor safety and system performance across normal operation, anticipated operational occurrences, and postulated accident conditions. Completion of this work strengthens the technical foundation underpinning SOLO’s safety analysis methods, modelling assumptions, and evaluation approaches that support key licensing deliverables.” He added that the PIRT will directly inform downstream licensing activities, including topical reports and safety analyses supporting the Preliminary Safety Analysis Report (PSAR).”
