Kyoto Fusioneering and Daido Steel have launched a joint development program to establish industrial manufacturing technology for low-activation vanadium alloy, one of three candidate materials for fusion reactor blankets. The initial results are already tangible: the two partners have melted and forged a combined 200 kg of high-purity vanadium into round bars and plates, and have begun jointly evaluating the processing technologies required.
The blanket is the internal reactor component that absorbs neutrons generated by the fusion reaction, recovers heat, and produces tritium used as fuel. Developing it with suitable materials is one of the most technically demanding challenges across the entire fusion supply chain. Among the candidate materials — reduced-activation ferritic-martensitic steels, silicon carbide, and vanadium alloy — the latter is attracting growing interest from private developers targeting high-temperature blanket designs. Its thermal advantages over RAFM steels have long been recognized; the persistent challenge has always been industrial producibility.
The V-4Cr-4Ti alloy, the sector’s reference composition, has a high affinity for elements such as carbon, nitrogen, and oxygen, making melting and processing particularly complex. Until now, production has remained confined to national research programs, never making the leap into an industrial supply chain. Through this agreement, Kyoto Fusioneering is scaling up high-purity vanadium production from laboratory quantities to a commercial specialty steel supply chain, leveraging Daido Steel’s established expertise in the development and manufacturing of advanced alloys.
The technical path leading to this point includes years of research conducted in collaboration with Professor Takuya Nagasaka of the National Institute for Fusion Science (NIFS), widely regarded as one of the world’s leading experts on vanadium alloys for fusion applications. Through that collaboration, Kyoto Fusioneering defined the specifications and evaluation methods required for structural materials in fusion facilities. Daido Steel now brings its manufacturing capabilities to bear on that established foundation.
On Daido Steel’s side, the agreement fits within the company’s Medium-Term Plan 2026, which has identified carbon neutrality by 2050 as a strategic priority and clean energy as one of its target sectors. The General Manager of the company’s Research and Development Center, Shigeki Ueta, stated that establishing mass production technology for vanadium alloy represents a significant technical challenge, but that the company intends to make a concrete contribution to the realization of commercial fusion through this development.
If the production technology is validated at industrial scale, vanadium could become the reference material for the blankets of next-generation private fusion reactors. Kyoto Fusioneering has already forged similar agreements with Kyocera for ceramic materials, building piece by piece a supply chain that does not yet exist. The step taken with Daido Steel addresses one of the hardest bottlenecks: bringing a well-known but never mass-produced material into a real commercial supply chain.
