A consortium of Japanese companies and academic institutions, led by Starlight Engine (SLE) and Kyoto Fusioneering (KF), has successfully completed the Conceptual Design Report (CDR) for the Fusion by Advanced Superconducting Tokamak (FAST) project. This is the first private fusion power demonstration project in Japan to reach this point and paves the way for the construction of a reactor to demonstrate electricity generation in the 2030s.
A private strategy with speed and clear focus
Unlike initiatives such as ITERwhich depend on international political consensus, the FAST project is FAST project project is managed by the Japanese private sector, which gives it agility in decision-making and efficiency in execution. The proposal is aligned with the National Fusion Energy Innovation Strategy promoted by the Japanese government, but without being subject to governmental processes.
During the development of the CDR, key aspects such as power generation technology, tritium management, remote maintenance and specifications of critical components such as coils and superconducting blankets were defined. The goal is not only to generate fusion power, but to demonstrate an integrated system that covers the entire fuel cycle and the conversion of heat to electricity.
Compact tokamak with 50 MW of fusion power
The proposed nuclear reactor proposes to use a low aspect ratio tokamak, optimized to sustain fusion reactions between deuterium and tritium (D-T), with a target power of approximately 50 megawatts. This configuration leverages decades of data and experience accumulated from previous projects such as JT-60SA, as well as the ITER design basis.
The FAST project will become the first global effort to integrate technologies on a scale relevant to commercial plants, such as liquid breeding blankets, tritium cycle systems and high-temperature superconducting blankets, with demonstrations planned at Kyoto Fusioneering’s own facilities (UNITY-1 and UNITY-2).
Road to construction in 2028
Engineering Design (EDR) is expected to be completed in 2028, with construction starting in the same year to demonstrate fusion power generation before 2035. In parallel, the site requirements and basic safety policy have already been published, with the Nuclear Regulation Authority involved in the approval process.
The CDR announcement will be presented publicly during the 42nd Annual Meeting of the Japan Society for Plasma Science and Nuclear Fusion Research, to be held December 1-4, 2025.
Source: Kyoto Fusioneering