ARPA-E award boosts CFS’ quest for the best fusion power plant materials

DEVENS, Mass., November 4, 2024 — Commonwealth Fusion Systems won a $2.5 million award from the US Advanced Research Projects Agency–Energy (ARPA–E) CHADWICK program to help advance fusion energy using new computational materials engineering. The award funds CFS and three partners to design, create, and start ramping up manufacturing of more robust materials for a key component of fusion power plants.

Through the program, CFS will design a combination of two materials that can withstand the fierce conditions inside the vacuum vessels at the heart of its ARC power plants. These machines, a type of fusion device called a tokamak, will use powerful magnets to confine and control a highly energetic cloud of ions and electrons called a plasma. The tokamak will heat the plasma beyond 100 million degrees Celsius inside the donut-shaped vacuum vessel, reproducing the sun’s power source on Earth. The power produced is transferred through the materials and out of the machine to generate steam and then electricity.

Fusion power plant operators will need to replace the vacuum vessel materials closest to the plasma periodically as those parts wear out. The materials available today, outpaced by fast improvements in fusion energy, aren’t ideal for this environment. Improving those materials can lower the power plant maintenance costs, making fusion more economically competitive.

With CFS’ first ARC power plant set to start generating energy for the electrical grid in the early 2030s, now is the time to develop the most promising materials for the first power plants.

To accelerate materials work for the first power plant, this project focuses on two materials that can handle the tokamak’s heat, radiation, and mechanical stress:

• a vanadium alloy for the vacuum vessel structure that must withstand the powerful forces within the machine while operating at high temperatures for many years
• a tungsten alloy for the inner wall that faces the plasma that has to endure the extreme conditions near the plasma

Both materials must survive neutron bombardment from the fusion process, and both must be fabricated in large enough amounts at low enough costs. By developing both materials together, the CFS team aims to meet all the power plant requirements simultaneously.

“We’ve developed the core engineering expertise — materials, processing, and fabrication included — to deliver whole fusion power plants, not just magnets,” said Cody A. Dennett, Director of Materials Technology at CFS.

Computational materials engineering

CFS staff will use computational engineering methods to design the vacuum vessel materials, iteratively co-designing the two materials then exploring the best ways to join them. Multiple computer models will predict material behavior across a range of conditions and length scales. This powerful approach can dramatically speed up product development while cutting costs, especially when working with manufacturing process constraints.

After the computing phase comes evaluation for each candidate material. The team will direct raw material production at leading US manufacturing experts ATI Technologies and Elmet Technologies, then oversee irradiation testing at the Michigan Ion Beam Laboratory at the University of Michigan to subject them to conditions similar to those inside a fusion machine.

ARPA–E’s CHADWICK award (Creating Hardened And Durable fusion first Wall Incorporating Centralized Knowledge) award is named after James Chadwick, who discovered the neutron in 1932. ARPA–E is an arm of the US Department of Energy that seeks to fund high-risk, high-impact energy science and technology programs.

CFS was one of two companies among the 13 CHADWICK award winners, and the only company designing new materials.

From SPARC to ARC

CFS selected the tokamak because it’s the best understood fusion device. The company is building its first tokamak, a test machine called SPARC, at its Devens, Massachusetts, headquarters.

For SPARC, CFS had to overcome design and engineering challenges with its pioneering high-temperature superconding (HTS) magnet technology that makes the machine much more compact and affordable. SPARC will pioneer most of the technology that ARC will use, but the CHADWICK project helps CFS tackle new requirements and ultimately deliver fusion power to the grid.

More broadly, the work also advances expertise in the United States for the field of integrated computational materials engineering (ICME).

“The project will help build US capabilities in rapidly scaling materials from computational design to high-volume production,” Dennett said. “Fusion, computation, and advanced fabrication all have accelerated. This work helps merge that progress into a big step toward practical fusion power plants.”

About Commonwealth Fusion Systems

Commonwealth Fusion Systems is the world’s leading and largest private fusion company. The company’s marquee fusion project, SPARC, will generate net energy, paving the way for limitless carbon-free energy. The company has raised more than $2 billion in capital since it was founded in 2018.

Contact: press@cfs.energy