Upgraded UC San Diego Facility Accelerates Efforts to Develop Materials for Fusion Reactor Walls

“The upgraded facility is a huge win for the nation’s fusion R&D community. Getting to this point has truly been a team effort over many years, and I am proud of each team member who has contributed to our progress to date,” said Tynan, a UC San Diego professor emeritus in the Department of Mechanical and Aerospace Engineering at the UC San Diego Jacobs School of Engineering. Tynan is now also affiliated with MIT. “There is still difficult work ahead, but we have an incredible opportunity to help make fusion energy commercially viable. I see this lab — in concert with other advances around the country — as a key step toward this collective goal.”

The facility is available for use by academic researchers, national laboratories and companies. Researchers interested in learning about opportunities to test materials in the upgraded facility can signal their interest here. This research facility is part of UC San Diego’s broader fusion engineering effort through the Fusion Engineering Institute.

Magnetic and Inertial Fusion Research Relevance

The upgraded facility can be used to expose materials samples to conditions that are very similar to what they would be exposed to in magnetic fusion reactions in tokamaks, the large doughnut-shaped devices that use powerful magnetic fields to create fusion energy. Doing this kind of research in today’s tokamaks is not possible as they do not yet produce fusion reactions at anything close to the rate that will be encountered in next-generation fusion devices.

In addition to advancing R&D for magnetic fusion, the upgraded facility is expected to be useful to teams developing new materials that can withstand the pulses of high-energy neutrons produced during inertial fusion reactions.

The facility could also be used to study aspects of materials that are expected to be used in fusion breeding blankets, which will be needed to produce the tritium fuel that will be consumed in the fusion device.

The Upgrade

The new ion beam accelerator is called POSEIDON. It is part of the larger PISCES fusion research laboratory built by Tynan and his team over the years. Before the development of the dual testing capacity of the upgraded facility, research groups focused either on how magnetic fusion reactor wall materials interact with plasma alone, without the effects of fusion neutron irradiation, or how they interact with neutrons alone.

Generating sufficient numbers of fusion neutrons is both technically challenging and very expensive, which is why the team turned to high-energy ions instead as a substitute for neutrons.

Understanding the effects of both plasmas and neutrons individually has been an important research question for decades. In the last few years, researchers have also seen hints that neutrons and plasma interact with one another to produce different effects on the reactor, but no careful and systematic investigation of these synergistic effects has been carried out until now.

Given that Tynan’s lab was already studying the effects of plasma on reactor wall materials with the PISCES-RF linear device that they developed, the team set out to design a system capable of also studying the effects of energetic ions that serve as neutron proxies.

The ions are created in the POSEIDON device and then hurtled across the laboratory at more than 1000 kilometers per second at energies of millions of electron volts. POSEIDON can produce ions from both gases and solid materials.

Two thirds of the way across the lab, the ion beams shot from POSEIDON meet a powerful magnetic field that steers the ion beams into the material sample within the plasma chamber. The setup allows researchers to study how the material reacts when it interacts with both plasma and high energy ions simulataneosly.

“The ion beam accelerator is up and running and fully integrated with the laboratory’s research infrastructure. We have already run a series of successful experiments, and our research collaborators are getting valuable data on their fusion-materials candidates that they can’t get anywhere else,” said Matthew Baldwin, Associate Research Scientist, Center for Energy Research at UC San Diego. Baldwin oversees the facility directly. “It’s extremely gratifying to be interacting with researchers from around campus and around the country who are getting ready to use the facility.”