Safe, cost-competitive, decarbonized energy for thousands of years
Stellaria’s innovative, compact, high-yield nuclear reactors are designed to support the transition to zero-carbon energy production. The company’s first reactor is slated for commissioning in 2035.
Molten salt reactors for electricity and heat production. Credit: Stellaria
Stellaria’s molten-salt fast-neutron reactor (MSFR), with its fourth containment barrier, is safe by design. It also offers electrical efficiency of 50%, flexibility of 20% to 30% of rated power per minute, and a competitive cost per MWh. The reactor runs on a fuel made from the recycling of current reactors’ used fuel (plutonium and minor actinides) and depleted uranium —resources that are readily available in France.
With advantages like these, the reactor will be especially beneficial for heavy industries with high and/or fluctuating demand for power. Electric utilities will also be able to leverage the solution to balance the grid as intermittent renewable energy penetration increases. The reactors will be deployed in pairs that require four hectares per production site to deliver up to 1,000 MW of heat or 500 MW of power, or any combination of heat and power up to this capacity.
The startup, whose five founders include three CEA employees, raised €2 million in capital in 2023 and secured €10 million in government funding in 2024. So far, Stellaria has established partnerships with Schneider Electric, Technip, and Orano. The technology is protected by eight patents, three of which are held jointly with the CEA. Continued R&D with the CEA will lead to Stellaria’s first demonstrator reactor, expected in 2029.
Key figure: 5000 years
If Stellaria reactors replaced all of France’s current nuclear power plants, the country’s existing inventory of nuclear waste would be enough to generate the same amount of power for 5,000 years
KEY Markets:
- Industry: data centers, glass manufacturing, iron and steel, chemicals, petrochemicals, semiconductors, and more
- Electric and other energy utilities
Technologies used:
- Molten-salt fast breeder reactor
- Heat and power generators
Year founded: 2023
CEA Institute: CEA-Iresne & CEA-Isas