The Materials Challenges Facing Fusion Energy
Commercially viable fusion energy requires materials that don't yet exist.
In my role as Venture Builder at MIT Proto Ventures, I have been deeply embedded in the MIT Plasma Science & Fusion Center (PSFC). I’ve experienced firsthand how fusion energy is entering a new stage of development. A dozen private companies are now investing billions of dollars to develop fusion pilot plants designed to deliver power to the grid in the early 2030s, with commercial plants planned later in that decade.
But as a technical person with a Ph.D. in materials science & engineering, one question has jumped out at me:
Out of what materials are we going to build these fusion power plants?
Together with my MIT colleagues Dennis Whyte, Tonio Buonassisi, Zach Hartwig, Sara Ferry, and Myles Stapelberg, I undertook to answer this question. What we found and summarized in a recent perspective article was both daunting and exciting:
Beyond the pilot stage, the materials required for commercially viable fusion power plants don’t yet exist.
The good news for anyone is rooting for fusion is that known materials will probably be good enough to build a pilot plant. This is because pilot plants don’t need to operate nearly continuously for decades, and aren’t expected to produce cost-competitive electricity, so their operating environment is relatively mild.
The bad news is that these known materials won’t cut it in a commercial fusion power plant. Even the most cutting-edge materials will melt, become activated by neutrons, become embrittled by hydrogen and helium, absorb tritium, and/or lose their technical performance in the exceptionally intense environment of a commercial fusion power plant.
Many different subsystems face materials challenges.
When experts think about fusion and extreme materials, they typically think of plasma-facing components, magnets, and blankets. It’s certainly true that these subsystems face some of the most difficult materials challenges due to their proximity to the plasma.
But in the course of our exploration, my colleagues and I found that several less-appreciated subsystems — including those for the fuel cycle, heat exchangers, sensors, insulating components, functional materials, and maintenance — also face crucial materials challenges in a fusion power plant.
Now is an exciting time for the materials science community.
What I’ve summarized above may sound daunting, but it is actually very exciting, especially for materials scientists looking to get involved in a new, extremely important, and (soon to be) well-funded field of research. As we write in our perspective article:
the magnitude of the technical challenge and the fast pace of commercial development, paired with the availability of several important sources of R&D funding, means that the field of fusion materials, formerly a niche branch of nuclear materials, now presents many research opportunities to a broader cross-section of the materials science community.
For materials scientists considering getting involved in fusion, there is plenty to be excited about including a lot of R&D funding in the pipeline:
A group of 35 countries committed at the COP28 international climate talks to pursue fusion research at an unprecedented scale
New commitments by China, Germany, the UK, and other countries to invest billions of dollars into fusion R&D, commercialization activities, and workforce training
The US Department of Energy’s Advanced Research Projects - Energy (ARPA-E) recently announced that they will be launching a funding program for fusion materials.
Not one to shy away from a hard challenge, especially one that could unlock firm energy production for the world without operational CO2 emissions, the materials science community has an exciting new problem to tackle.
The jury is still out about what role fusion will play in the future1. But if a meaningful role in the clean energy mix of the 21st century, now is the time to develop the materials that will make it possible.
Thank you to my colleagues Dennis Whyte, Tonio Buonassisi, Zach Hartwig, Sara Ferry, and Myles Stapelberg at MIT for collaborating on this work with me. You can read the full pre-print of our perspective article on fusion materials below:
Cohen-Tanugi, D., Stapelberg, M. G., Short, M. P., Ferry, S. E., Whyte, D. G., Hartwig, Z. S., & Buonassisi, T. (2023). "Materials for Fusion Energy: Key Challenges and Guiding Principles for Developing Under High Design Uncertainty." arXiv preprint arXiv:2311.12187.
For a highly readable summary of fusion energy and the various technical & economic barriers that fusion will have to clear in order to meaningfully contribute to the grid, read this great fusion writeup by Ben James.