French start-up Stellaria raises €23 million for its molten-salt nuclear reactor

GRENOBLE, France, July 24, 2025 /PRNewswire/ -- Stellaria, a French start-up originating from CEA and Schneider Electric, has announced that it has raised a total of €23 million to develop its fast neutron molten salt nuclear reactor by 2035. This new round of funding comes two years after a successful first round in 2023.

The round was co-led by US impact fund At One Ventures and Supernova Invest, alongside Stellaria's historical investors, including CEA Investissements, Schneider Electric, Exergon, and Technip Energies.

In addition to the €10 million in non-dilutive financing obtained by Stellaria through its success in the France 2030 'Innovative Reactors' call for projects, this funding will be used to finance all the technical and regulatory studies necessary to establish a first molten-salt facility capable of sustaining a fission reaction, scheduled for 2029.

Founded in 2023, Stellaria is developing the Stellarium, a fourth-generation molten-salt nuclear reactor capable of fully regenerating its fuel during operation. It will therefore be self-sufficient for more than 20 years, while reducing long-lived nuclear waste (minor actinides). The first production unit is expected to be offered for commercial deployment by 2035. Competitive, safe and flexible, the Stellarium will also help to decarbonise energy production, whether for industry or the grid. By replacing fossil fuel sources with Stellarium, it will be possible to cut CO2 and particulate emissions from industrial sites by 99%.

Thanks to this funding, Stellaria aims to double its workforce to accelerate R&D around its reactor and finalise the development of one of the world's first liquid-core fast-neutron reactor demonstrators. This step will allow it to develop its research laboratory in Grenoble by several million euros, to continue its scientific and industrial collaborations, and submit an Application for Authorisation to Create (DAC) a Basic Nuclear Installation (INB) to the safety authorities for the construction of its prototype.

Nicolas Breyton, CEO of Stellaria, said: "This funding round demonstrates the confidence of investors in the technical maturity of our molten-salt reactor, which opens up a new path towards the circular economy of the fuel cycle. We are laying the foundations for a model in which electro-intensive industries become self-sufficient in energy throughout the lifetime of their facilities. This is a key step towards the sustainable reindustrialisation of our territory."

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Press contact:
Comclean
Anna Denysova
anna@comclean.fr

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SOURCE Stellaria