In a significant advancement infor the field of fusion energy, Helical Fusion Co., Ltd., has successfully conducted a critical test involving a 19kA current in its proprietary High-Temperature Superconductor (HTS) cable. This milestone experiment positions the company at the forefront of achieving a steady-state fusion reactor, establishing a new standard in the fusion energy domain.
The company's state-of-the-art HTS cable, developed and manufactured in-house, has showcased superior superconductivity at cryogenic temperatures of -253°C (20 Kelvin) within a high magnetic field environment of 8 Tesla. Conducted at the esteemed National Institute for Fusion Science (NIFS) in Toki City, Gifu Prefecture, this test highlights Helical Fusion's cutting-edge expertise in HTS magnet technology. NIFS, known for its sophisticated conductor testing facilities, offered an optimal venue for this critical demonstration(refer to Figure1).
The HTS cable, crafted with 30 layers of REBCO (a top-tier HTS wire), constituted a durable conductor with a cross-section of approximately 3 cm and a length exceeding 4 meters(refer to Figure 2,3). This configuration underwent testing nearly at the maximum capacity of the facility, 20 kA. Helical Fusion aims to significantly enhance this current capacity by integrating additional HTS wires, targeting a current density of over 100 amperes per square millimeter. Such high current density is vital for the development of fusion reactors to be both compact and, efficient fusion reactors. The experiment also introduced an innovative HTS wire joint technique, facilitating the scalable production of these advanced conductors.
This development marks a significant stride in the pursuit of fusion energy, widely regarded as the ultimate clean energy solution, amidst current global fusion competition. Helical Fusion's efforts have been substantially supported by a 2 billion yen grant from the Japanese government in October 2023, under the SBIR Phase 3 program, representing the most substantial per-company investment in the fusion sector. This backing propels the company's advancements in HTS and fusion reactor development, with plans for additional tests on double-pancake coils in 2025 and helical coils subsequently.
The innovative conductor design, spearheaded by Dr. Junichi Miyazawa, Head of R&D at Helical Fusion, leverages NIFS's extensive research in superconductor technology. Characterized by its high current density and wound-ability, this conductor holds promise for broad applications beyond fusion reactors(refer to Figure4).
In collaboration with industry leaders like Fujikura Ltd., Metal Technology Co., Ltd., and NIFS, Helical Fusion is driving innovation in superconductivity. The company is dedicated to leading the global initiative in developing advanced conductors, to showcasewith the objective of showcasing a world-class, economically viable fusion reactor in the foreseeable future.
Comment from Mr. Takaya TAGUCHI (CEO)
At the core of a fusion reactor's electromagnets (coils)—the very heart of the system—lies HTS technology. This innovation is pivotal not only for enhancing the compactness and efficiency of commercial reactors but also for securing a leading position in the global fusion industry. Achieving a breakthrough in HTS technology ahead of international competitors marks a crucial step towards the commercialization of fusion reactors. It also positions Japan to take the lead in the fusion sector. This significant milestone in development was reached through the collaborative efforts of our partner companies and research institutions. We are committed to advancing this technology further, driving us closer to the commercialization of fusion energy.
This phrasing adds emphasis.
Figure1: Carefully Installing the HTS Cable Testing setup into the Test Facility
Figure2: HTS Cable in Production at approx. 3 cm square
Figure3: The HTS Cable Prepared for Tests
Figure4: The HTS Cable Sample in Bent State