Researchers from Thea Energy, Inc., led by C. P. S. Swanson and a team of scientists and engineers, have developed a preconceptual design for a fusion power plant called “Helios.” This design is based on a novel planar coil stellarator architecture, which aims to leverage the stability and steady-state capability of stellarators while incorporating practical engineering constraints.
The Helios design focuses on a two-field-period quasi-axisymmetric stellarator equilibrium with an aspect ratio of 4.5 and a unique tokamak-like X-point divertor. The team utilized state-of-the-art, high-fidelity codes to calculate stability and transport, ensuring the design is grounded in the performance of existing experiments. The electromagnetic coil set is composed of high-temperature superconducting (HTS) materials, including 12 large plasma-encircling coils and 324 smaller field-shaping coils. All coils are planar and convex, with a maximum on-coil magnetic field of 20 Tesla, a value already achieved in existing large-bore HTS coils. The design ensures a minimum of 1.2 meters between the plasma and coils, providing space for a tritium breeding blanket and neutron shielding, which extends the operational lifetime of the coils to a minimum of 40 years.
One of the key features of the Helios design is its practical maintenance architecture. The power plant is divided into toroidal sectors that can be removed for maintenance, with an estimated biennial maintenance cycle taking approximately 84 days, resulting in an 88% capacity factor. The shaping coils are individually controllable, allowing for a configurable magnetic field that relaxes manufacturing and assembly tolerances and enhances plasma control. The design also enforces rigorous engineering constraints such as temperature and stress limits to ensure robustness and reliability.
The Helios design aims to produce 1.1 GW of thermal power and 390 MW of net electric power. This innovative approach to fusion power plant design could potentially offer a more stable and efficient alternative to traditional tokamak designs, with practical applications in the energy sector. The research was published in the journal [Fusion Engineering and Design], providing a detailed overview of the Helios design and its potential benefits for the future of fusion energy.
In summary, the Helios design by Thea Energy, Inc. represents a significant step forward in the development of practical fusion power plants. By leveraging the stability and steady-state capability of stellarators and incorporating advanced HTS materials and maintenance architectures, the Helios design offers a promising pathway to achieving sustainable and efficient fusion energy.
This article is based on research available at arXiv.