The Stellaris concept builds on results obtained from IPP’s Wendelstein 7-X (W7- X) fusion research facility, a QI stellarator experimental prototype located in Greifswald, eastern Germany. This has received over €1.3 billion in funding from the German federal government and the European Union.
The Stellaris development is the result of a public–private partnership between Proxima Fusion engineers and IPP scientists. Proxima Fusion says it has been “building on the institute’s cutting-edge experimental and theoretical work, with a strong engineering workforce from the likes of Google, Tesla, McLaren Formula-1, and SpaceX.”
“The path to commercial fusion power plants is now open,” says Dr Francesco Sciortino, cofounder and CEO of Proxima Fusion.
Stellaris is said to be both smaller and more powerful than any stellarator power plant designed to date, making use of the much stronger magnetic fields that are enabled by high temperature superconductor (HTS) based magnets.
Smaller reactors can be built more quickly, provide more efficient power generation, and will eventually be more cost-effective in terms of both construction and operation. The Stellaris concept also makes use of only currently available materials, says Proxima Fusion, meaning it will be buildable by expanding on today’s supply chains.
A simulation-driven engineering approach has enabled rapid design iterations, leveraging advanced computing, with Stellaris described as “the first QI-stellarator-based power plant design that simultaneously meets all major physics and engineering constraints, as demonstrated through electromagnetic, structural, thermal, and neutronic simulations.” The integration of physics and engineering constraints within a single optimisation framework allows Proxima to “now take a bold leap with its demonstration stellarator, Alpha, as opposed to building several devices with incremental improvements over a period of decades.”
The groundbreaking technical features of the Stellaris design include a neutron blanket concept that is adapted to the complex geometry of stellarators.
Thanks to its Stellarator Model Coil (SMC) magnet demo scheduled for 2027, Proxima Fusion says it “will fully de-risk HTS technology for stellarators.”
It then plans to demonstrate that stellarators are capable of net energy production with its demo stellarator, Alpha, in 2031, and – exhibiting no lack of ambition – aims to “deliver limitless, safe, clean fusion energy to the grid in the 2030s.”
Stellarator vs tokamak
Stellarators and tokamaks both employ ring shaped plasma-containing magnetic fields. But tokamaks produce part of these fields by means of an electric current flowing in the plasma, while stellarators, in contrast, form the magnetic field cage solely by means of external coils.
Stellarator magnets have complex shapes because they are designed to create twisted magnetic fields that confine plasma without relying on plasma current.
This article first appeared in Modern Power Systems magazine.
