Helical Fusion targets 2027 tests at Japanese pilot fusion reactor

Toki, Japan. Japanese startup Helical Fusion said Tuesday it expects to begin preliminary power-on tests at its demonstration fusion reactor in 2027. The project is a step towards its goal of developing a commercially viable fusion power plant.

Pilot reactor

The company is developing Helix HARUKA, Japan’s first integrated pilot reactor using the helical approach to fusion. It is designed to test whether stable, continuous fusion reactions are feasible.

Fusion generates heat by combining atoms at extremely high temperatures, as the sun does. It could eventually provide large amounts of clean power with little radioactive waste compared with existing fission reactors, but 70 years of research have not produced a commercially viable reactor.

Construction and testing

Helical Fusion said it cleared a key hurdle in 2025 when it completed a performance test of a high-temperature superconducting coil. The test replicated the magnetic environment inside a fusion device and achieved a stable current flow under superconducting conditions, which the company described as a world first.

Construction of the first spiral coil began early this year at the National Institute for Fusion Science (NIFS) site in Toki, central Japan. The work is now largely complete, allowing the company to open the facility to the media.

If the first-stage tests succeed, Helical Fusion plans to install a second coil and other major components, including a liquid-metal wall blanket. It then aims to conduct power-on tests of the completed integrated facility around 2030.

Commercial plans

The company plans to follow HARUKA with HELIX KANATA, a larger reactor designed for a net power output of 50 MW and intended to demonstrate stable, continuous power generation. It expects to begin full-scale investment in that project in the 2030s.

Helical Fusion is the sole private-sector inheritor of helical fusion technology developed by NIFS, one of the world’s largest fusion research facilities. It aims to develop the first commercially viable fusion power plant based on the helical design.

CEO Takaya Taguchi told reporters the company hopes to build a commercial power plant as early as the 2040s. He said commercial operations would first require overcoming hurdles involving cost, safety and construction speed, as well as technical challenges.