Magnetic Confinement's Supply Chain Challenges

Advancements in High-Temperature Superconducting (HTS) magnets have paved the way for companies pursuing magnetic confinement-based approaches to fusion, including Commonwealth Fusion Systems and Tokamak Energy. These magnets give startups a potential edge over larger projects like ITER, which rely on more mature, but lower-performance, low-temperature superconductors. ​​

High-temperature superconductors, in the form of thin, flat tapes or wire, can be run at much higher field strengths, enabling smaller and more cost-effective reactor designs. They also operate at higher temperatures than LTS material and can be cooled with liquid nitrogen, which is cheaper and easier to handle than liquid helium.

Among HTS materials, rare-earth barium copper oxide (REBCO) stands out for its potential in fusion applications. Both Tokamak Energy and Commonwealth Fusion Systems have focused on REBCO-based magnets for their ability to carry high current densities at temperatures of 20–30K and in magnetic fields of 20 tesla or more. 

Companies like CFS and Tokomak Energy have increased the demand for superconducting wire and tape from hundreds of kilometers per year to thousands. Commonwealth Fusion’s Sparc reactor alone, for example, will require 10,000 kilometers of superconducting wire.

This surge in demand has exposed significant supply chain bottlenecks for HTS materials. The United States has limited manufacturing capacity (although building up domestic capacity is a key strategic priority), so startups have had to turn elsewhere.

Tokamak Energy, for instance, signed an agreement in January 2023 with Furukawa Electric Group to supply HTS tape for its new prototype fusion device, ST80-HTS. However, even Furukawa, a multinational conglomerate, has identified supply chain disruptions caused by economic and political factors as high impact, high likelihood risks to its business.

Commonwealth Fusion Systems has seen these geopolitical risks materialize in a more visceral way. A key HTS supplier for CFS has been SuperOx, a Russian company with production facilities in Moscow and Japan. In 2021, SuperOx manufactured over 300 km of 4-mm-wide YBCO tape in 9 months, with most of it going to CFS. This was shortly before the Russian invasion of Ukraine, and today the company faces real risk from international sanctions.

CFS’s HTS magnets owe their development to breakthroughs in YBa₂Cu₃O₇ (YBCO) production, with uniformly distributed Yttrium Oxide nanoparticles enabling a more consistent microstructure. This introduces another layer of supply chain complexity. China currently dominates the supply side of the equation for Yttrium, with its large reserves and processing capabilities.

According to data from the U.S. Geological Survey, the U.S. is entirely dependent on imports of Yttrium, 93% of which come from China (note: the USGS data looks specifically at imports from 2020–23). In recent weeks, China has already demonstrated a willingness to clamp down on exports of rare earth minerals. As geopolitical tensions continue to escalate, further supply chain disruptions seem increasingly likely. The result could be even more delays as fusion startups race to bring their prototypes online.