Renaissance Fusion, a magnetic-confinement fusion company founded in 2020, is devoted to building a stellarator reactor on Earth with the goal of decoupling energy consumption and carbon emissions.

Most energies we use on Earth ultimately come from the sun, be it non-renewable energy sources like coal and oil, or renewables like wind, water and tidal power. The sun is subjected to high temperature and pressure inside, enabling nuclear fusion reactions, which can release huge energy, all the time.

If we humans can replicate the sun’s controlled nuclear fusion on the earth, we will be able to obtain inexhaustible clean energy and overcome the current aggravating environmental degradation and energy shortage and other problems.

Controlled nuclear fusion refers to the reaction that can output long-term stable and safe energy on the basis of controlling the scale and speed of fusion.

At present, there are many approaches to controlled fusion. Magnetic confinement fusion is one of them, which mainly confine fusion fuels in the form of plasma with magnetic fields, and output energy. Stellarator and tokamak are two typical fusion reactors.

Usually, a stellarator is composed of twisted cylinder blocks and a coil wrapped around the outside. Its powerful magnetic field mainly relies on powerful magnets placed precisely along the structure, confining the hot plasma in the confinement chamber.

Because of the design complexity, most fusion devices are tokamaks. However, Renaissance Fusion is taking a different path, focusing more on its stellarator research.

“We have a technology that is pretty unique,” Renaissance Fusion founder Francesco Volpe told the media. Instead of designing complicated three-dimensional coils to generate a magnetic field, Renaissance Fusion greatly simplifies this process by drawing tracks on a cylinder.

After some calculation based on the magnetic field that they want to generate, the team can determine the shape of the coils that they need.

The cylinder rotates around an axis while a device moves left and right to engrave tracks with a laser on the surface of the cylinder. Cylinder blocks are then combined together to form a reactor.

Fig.1 Simplified surface of the stellarator coil winding

(Image Credits: Renaissance Fusion website)

As for the neutrons emitted by the nuclear reaction inside the cylinder, Renaissance Fusion wants to use liquid Lithium to create thick walls that separate plasma from the outside world.

“We inject a layer of liquid metal. It flows around the inside of the cylinder and then it’s extracted at the bottom. It’s thick enough to absorb the majority of the neutrons,” Volpe said.

FIG. Neutron shielding and heat extraction

(Credit: Renaissance Fusion website)

At the same time, the liquid metal can extract heat from the stellarator and produce steam for electricity generation.

According to the startup’s founder, Renaissance Fusion is quite innovative with its use of liquid metal. “We are the only one in commercial magnetic fusion where the liquid lithium faces the plasma,” Volpe said.

Right now, the company can create liquid Lithium-based walls that are 1-centimeter thick. It will require a lot of iterations before it can be used in nuclear fusion as Renaissance Fusion estimates that it would require a thickness of 30 to 40 centimeters.

01 €15 Million Seed Round Funding

Renaissance Fusion has raised €15 million in funding in a seed round led by Lowercarbon Capital. Several European investors also participated in the round, including HCVC, Positron Ventures and Norssken.

“We are proud to support Francesco Volpe and his team in the emergence and industrialization in France and in Europe of a disruptive solution in energy production and distribution technologies. Grenoble is a highly strategic location that allows them to benefit from a favorable environment for the development of nuclear energy, a strong ecosystem and an unrivaled pool of talent,” Alexis Houssou, founder and managing partner at HCVC, said in a statement.

With the funding round, Renaissance Fusion plans to triple the size of its team to 60 people by the end of 2023 to purchase facilities, conduct research and development, and initiate the first experiment. The company is already considering commercial applications for its technologies that could be released before the 2030s.

Volpe believes that the coil patterning technology could be used for MRI and energy storage — “whenever you need a strong magnetic field, a large volume and high precision,” he said.

In addition, the company plans to inaugurate its first reactor with a power of 1 GWe and sell it to operators and nuclear power plant builders.

References:

1.https://techcrunch.com/2023/01/26/renaissance-fusion-raises-164-million-to-build-nuclear-fusion-technology-in-europe/

2.https://www.neimagazine.com/news/newsrenaissance-fusion-raises-funds-to-build-nuclear-fusion-technology-in-europe-10561736

3.https://business.lesechos.fr/entrepreneurs/idees-de-business/0703281556474-renaissance-fusion-le-fleuron-francais-de-la-fusion-nucleaire-350853.php