French start-up Stellaria, launched by the Alternative Energies & Atomic Energy Commission (CEA) in March 2023 has announced raised a total of €23m ($26.7m) to develop its fast neutron molten salt nuclear reactor by 2035. This new funding round comes two years after the first round in 2023.
The new 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. Stellaria was advised by the law firm Yards and by Optiva Capital for the fundraising, while the investors were advised by the law firms Chammas & Marcheteau and Goodwin.
The new funding is in addition to €10m in non-dilutive financing obtained by Stellaria through its success in the France 2030 Innovative Reactors call for projects.
The funding will be used to finance all the technical and regulatory studies necessary with the aim of delivering a molten-salt facility capable of sustaining a fission reaction in 2029.
Stellaria aims to use the funding to double its workforce to accelerate R&D around its reactor and finalise development. This will allow it to develop its research laboratory in Grenoble, 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.
“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,” said Stellaria CEO Nicolas Breyton, of, said: 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.”
Stellaria aims to develop an energy system based on a chloride molten salt reactor. This technology integrates the fuel in liquid form, dissolved in molten salts which also constitutes the coolant. Liquid fuel can remain almost continuously in the reactor core. Its main advantages are in the combination of energy production and multi-recycling of fuel with a high level of passive safety by design.
The proposed reactor will be very compact measuring 4 cubic metres and will produce 250 MWt. It will be able to use a diversified range of nuclear fuels including uranium, plutonium, MOX, minor actinides, and even thorium.
“We invested because Stellaria is solving the core technical and economic barriers holding back nuclear, cost, complexity, and waste”, explained lead investor Laurie Menoud, Partner at At One Ventures. “The reactor offers low CAPEX and LCOE, passive safety with 72-hour cooldown, fuel flexibility, and fast power ramping. Add to that a favourable regulatory environment in France and early strategic engagement, and Stellaria stands out.”
Francois Breniaux, General Partner at Supernova Invest, explains: “Based on a unique development approach, Stellaria offers the only viable solution for many industries requiring a high-power energy supply, long-term price stability, and the operational flexibility of gas-fired power plants.
This capability is essential both for sustaining traditional strategic electro-intensive sectors (such as steel and chemicals) and for enabling the growth of emerging industries, including CO₂-free hydrogen production and data centres driven by the rise of artificial intelligence.”
Frédéric Godemel, Executive Vice President Energy Management at Schneider Electric said, “Stellaria is on track to develop the world’s first fast neutron molten-salt nuclear reactor by 2035. This project will offer affordable and impactful solutions for industrial decarbonisation, a tangible sign of the progress being made in the industry.”
Benjamin Lechuga, Chief Strategy & Sustainability Officer at Technip Energies said: “We will support Stellaria in the industrial scale-up of this controllable, low-carbon energy production technology through concrete projects. This support reflects our commitment to long-term innovation and our belief in the complementary nature of energy solutions serving decarbonisation.”
Giuseppe Sangiovanni, Co-founder and Managing Partner at Isospin Exergon commented: “We invested in and supported Stellaria from the very first round, and we are delighted with the progress the company has made since then, as well as the growing business prospects.”
