Lawrence Livermore National Laboratory uses 3D printing for ignition-grade targets.
There are some technologies that always seem to be just over the horizon without ever coming closer: fully capable humanoid robots, widely available autonomous vehicles, general artificial intelligence and, of course, fusion power.
The biggest recent development on that last one is probably the 2022 experiment at Lawrence Livermore National Laboratory (LLNL) which saw a successful fusion ignition, but the scientists and engineers working at LLNL aren’t content to stop there.
“Now that we have achieved and repeated fusion ignition,” said Tammy Ma, lead for LLNL’s inertial fusion energy institutional initiative, in a press release, “the Lab is rapidly applying our decades of know-how into solving the core physics and engineering challenges that come with the monumental task of building the fusion ecosystem necessary for a laser fusion power plant. The mass production of ignition-grade targets is one of these, and cutting-edge 3D printing could help get us there.”
The ignition targets Ma refers to are nearly perfect spheres of hollow diamond encasing deuterium and tritium (DT) fusion fuel. These are suspended inside a hohlraum: a cavity with walls in radiative equilibrium with the radiant energy within the cavity. Under exposure to intense laser energy, these hydrogen isotopes fuse and, ideally, produce more energy than needed to start the reaction.
Unfortunately, these targets take months to manufacture, while a functioning fusion energy power plant would require nearly one million targets per day, igniting at a rate of ten times a second. The physical reaction would be similar to the ignition already achieved at LLNL, but the production of targets requires a fundamentally new approach that can work at scale.
Enter 3D printing, with a new LLNL project focusing on constructing a workflow to design, fabricate, characterize and field fully 3D-printed fuel capsules. The project is also developing a first-of-its-kind dual-wavelength, two-photon polymerization (DW-2PP) approach to meet the stringent engineering demands of ignition targets.
“We are focusing on a specific type of wetted-foam capsule, in which liquid DT can be wicked into a uniform foam layer on the inside of the spherical capsule by capillary action,” said Xiaoxing Xia, co-principal investigator and a staff scientist at LLNL. “The current DT ice layering process takes up to a week to complete with extreme meticulousness. It’s possible that 3D printing is the only tool for this kind of complex geometry at scale.”
If successful, this project could address critical bottlenecks towards 3D printing ignition capsules in their entirety.
“Our DW-2PP printer uses two light sources with different wavelengths to selectively print different materials with sub-micron resolution,” explained co-principal investigator James Oakdale in the same press release. “This novel capability gives us exquisite control over the spatial chemistry and densities within both the capsule and inner foam material, which allows us to respond quickly to bespoke or one-off capsule designs.”
According to LLNL, the work is already showing promise, with 3D printed targets successfully used during two fusion experiments in 2024 and more expected in the year ahead.
Could 2025 finally be the year we achieve fusion power?
Probably not, but at least we’re still making progress.
