Japan’s FAST fusion project clears key design milestone

Starlight Engine and Kyoto Fusioneering have completed the conceptual design for Japan’s FAST fusion demonstration plant, one year after the project began in November 2024. The Conceptual Design Report outlines FAST’s objectives, system design, feasibility and schedule, and is Japan’s first privately led fusion demonstration report aligned with the national Fusion Energy Innovation Strategy.

FAST is a low aspect ratio tokamak targeting about 50 MW of fusion output using deuterium tritium plasma and neutral beam heating in a device similar to JT 60SA. The project aims to show an integrated fusion system covering energy conversion, tritium breeding, fuel cycle technologies and remote maintenance at a scale relevant to commercial plants.

The design draws on Japan’s work on JT 60SA, ITER and DEMO and uses high temperature superconducting magnets and liquid breeding blankets. The team said completing the work in a year is unusually quick.

Starlight Engine leads the project with Kyoto Fusioneering and researchers from major universities, supported by companies including Fujikura, Furukawa Electric, Hitachi, J Power, Kajima, Marubeni, Mitsubishi Corporation, Mitsui and Sumitomo Mitsui Banking Corporation.

FAST now moves to engineering design, with a detailed report expected in 2028 and construction planned after 2028. Work is underway on site selection, safety engagement with the Nuclear Regulation Authority and funding arrangements from 2026. A power generation demonstration is targeted by the late 2030s.

Image Source: Kyoto Fusioneering