Proxima Fusion taps Japan to build its fusion plant

Fujikura and Kyoto Fusioneering are two Japanese industrial firms most people have never heard of. On Oct. 28 in Tokyo, they signed supply deals with Proxima Fusion, a well-funded fusion startup based in Munich. Proxima is building a stellarator, a reactor that uses twisted magnets to hold burning plasma in place. The Japanese partners will help supply the hardware.

This is one deal in a bigger scramble. Companies and governments across Europe, Japan, the US, and China are all racing to build it. The prize: the first fusion plant that actually sells power to the grid. Kyoto Fusioneering already works on gyrotrons, devices that blast plasma with microwaves hot enough to fuse atoms together. None of this is a working power plant yet. It's a supply chain being built years ahead of the machine it's meant to serve.

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Will a stellarator actually beat the more common tokamak design to market? Most fusion money today still goes toward tokamaks, donut-shaped reactors that are easier to build but harder to run nonstop. Proxima is betting on the harder stellarator design instead, because once working, it can theoretically run continuously. These Japan supply deals are Proxima building up that bet years before anyone knows if it actually pays off.