Renaissance Fusion raises funds to build fusion technology in Europe

Grenoble and Houston-based French startup Renaissance Fusion has raised $16.4 million in seed funding led by Lowercarbon Capital. Renaissance Fusion, founded in 2019 by Francesco Volpe and Martin Koop, is working on the development of a stellarator reactor. The company expects to be able to deliver a small fusion reactor with a capacity of 1 GWe in 2030. It does not plan to operate the plants directly, but will sell its reactors to plant designers and operators.

Several European investors also participated in the round, including HCVC, Positron Ventures and Norssken. Unruly Capital led the company’s seed stage. Using the new funding, Renaissance Fusion plans to triple the size of its team to 60 people by the end of 2023.

Renaissance Fusion offers a unique set of technologies that it plans to use in its stellarator fusion reactor. These include liquid metal that adheres to the inner walls of the reaction chamber, insulating the walls from extreme heat and radioactivity and reducing maintenance costs. The company also develops high-temperature superconducting coils. They generate strong magnetic fields, allowing a smaller reactor to achieve the same performance as a larger one.

A new manufacturing process using high temperature superconducting magnets (HTS) allows the reactor to be separated into individual modules. “We have technology that is quite unique,” Renaissance Fusion told Techcrunch. Instead of designing complex three-dimensional coils to generate a magnetic field, the company simplifies this process by drawing traces on a cylinder using a laser.

After a calculation based on the required magnetic field, the team can determine the shape of the required coils. The cylinder rotates around an axis while a device moves left and right to etch laser marks on the surface of the cylinder. The cylindrical blocks are then combined to form a reactor.

To cope with the neutrons emitted by the fusion reaction inside the cylinder, liquid lithium is what lines the walls containing the plasma.

Volpe explained: “We inject a layer of liquid metal. It flows around the inside of the cylinder and is then extracted at the bottom. It is thick enough to absorb most of the neutrons.

The design of the liquid metal walls inside the reactor offers several advantages, according to project manager Simon Belka. “Liquid lithium protects the solid walls of the reactor, absorbs neutrons much better, directs the heat produced by the fusion to the secondary circuit and the turbine producing electricity, and finally, reacting with the plasma, creates the tritium needed for the operation. “

Volpe said Renaissance Fusion is innovative in its use of liquid metal. “We’re the only one in commercial magnetic fusion where liquid lithium faces plasma.” Currently, the company can create liquid lithium-based walls 1cm thick. It will require significant development before it can be used in nuclear fusion , which will require a thickness of 30-40 cm.

The company is already considering commercial applications for its technology, which could be launched before 2030. Volpe believes the coil patterning technology could be used for MRI and energy storage – “anytime you need a strong magnetic field, a large volume and high accuracy,” he said.

By 2024, Renaissance Fusion intends to finalize the design of its two technologies. Once these proofs of concept are complete and marketing begins, the company will work on building the first experimental reactor to specifically demonstrate that it is capable of producing more energy than is needed. Finally, in early 2030, it is due to launch its first 1 GWe reactor capable of injecting electricity into the grid. “Compared to large international public projects, startups offer an interesting alternative: we bring new ideas, take more risks to create disruption and are less dependent on public funding,” Belka said.

Image: Renaissnace Fusion’s executive team, including founder Francesco Volpe (center) (Courtesy of Renaissance Fusion)

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