Compared with current nuclear fission technology, nuclear fusion has theoretically unlimited power generation capacity and is considered the ultimate solution for humanity's endless energy needs. Multiple major countries are now actively constructing nuclear fusion power plants, with some even expected to start generating electricity in as soon as two years.
Japan also harbors great ambitions in this field. Today, its startup Helical Fusion has achieved a new record, marking a milestone in the commercialization of nuclear fusion—it successfully conducted the world's first full-function performance test of HTS (High-Temperature Superconducting) coils based on stellarator technology.
Understanding this technology requires knowledge of the two main technical routes for nuclear fusion. As many learned in middle school, nuclear fusion requires extremely high temperatures, far beyond what any metal can withstand. Magnetic confinement is therefore necessary, which mainly falls into two technical categories: tokamak and stellarator.
While the specific technical details are complex, the International Atomic Energy Agency (IAEA) has provided a simplified explanation: tokamaks excel at maintaining the temperature of plasma, while stellarators are superior in ensuring plasma stability. However, stellarators are more complex and technically challenging to develop.
Currently, there are approximately 60 tokamaks and 10 stellarators in operation worldwide. The breakthrough achieved by this Japanese startup falls under the stellarator route.
Helical Fusion claims to be the only company globally based on Helical Stellarator technology, with 60 years of technical accumulation from Japanese research institutions and universities. The company is advancing the HPLF (Helical Plasma Fusion Reactor) project to build the world's first commercial nuclear fusion power plant using this technology.
In simple terms, this test successfully verified the performance of HTS superconducting magnet coils, achieving breakthroughs in three key aspects:
The HTS coils were specifically designed for commercial nuclear fusion power generation.
The test reproduced the magnetic field environment of a nuclear fusion device, including both self-generated and external magnetic fields.
Stable current tests under superconducting conditions were successfully conducted.
The test confirmed that the HTS coils could maintain a stable superconducting current of 40 kA (kiloamperes) under a magnetic field strength of 7 Tesla and a temperature of 15 Kelvin (-258°C). Notably, these HTS coils do not require electrical insulation, making this the world's first successful test of large-scale, insulation-free high-temperature superconducting coils.
Helical Fusion plans to build the world's first commercial nuclear fusion power plant in the 2030s, with the project expected to cost 5 billion US dollars.
Furthermore, the power plant must meet three basic requirements for commercial viability:
24/7/365 stable operation;
Net energy output (generated electricity exceeds input electricity);
Easy maintainability.