A rural electric cooperative board weighing its first advanced reactor usually runs into the same wall: the fuel costs more than the board can justify to its members. Hank, a board member at a small electric cooperative in rural Iowa, has sat through that exact budget meeting more than once. A new fuel-printing partnership announced this August is aimed squarely at knocking that wall down.
What LLNL and Ampera Just Announced
Lawrence Livermore National Laboratory and nuclear fuel startup Ampera announced a partnership called THUNDER on August 27, targeting the exact bottleneck that has kept TRISO fuel expensive: how you actually make the tiny fuel spheres inside it. TRISO fuel packs a uranium or thorium kernel inside layers of ceramic coating that trap radioactive material even if the reactor overheats, which is why regulators treat it as its own built-in containment system. The catch is manufacturing: each kernel needs to be nearly perfectly round and uniform in size, or the coating layers don’t form correctly.
LLNL engineer Viktor Sukhotskiy built the answer to that problem back in 2023. His PowderJet project uses liquid metal-jetting, essentially a droplet-on-demand printer for molten metal, to produce spherical particles with tight control over size and shape. THUNDER adapts that technique specifically for thorium-232 kernels.
Why Thorium Changes the Math
Thorium is far more abundant than uranium, and reactors that use it produce less long-lived radioactive waste. Thorium-232 also isn’t fissile on its own, so it’s harder to weaponize. When a neutron hits it, it converts into fissile uranium-233, letting a reactor effectively breed part of its own fuel supply as it runs. Ampera, founded in 2025, set up an Australian subsidiary in June to secure thorium supply and produced a full-scale silicon carbide reactor core model using 3D printing in July.
Cost has been the main obstacle blocking thorium TRISO fuel from wider use. A manufacturing process that produces more uniform kernels means fewer rejected batches and lower production costs, which is exactly what advanced reactor developers need before TRISO-fueled designs can compete on price with conventional fuel. Standard Nuclear’s multi-year TRISO fuel deal for Radiant’s Kaleidos microreactor shows demand for this fuel type is already growing. Every dollar shaved off kernel production eventually shows up in the price tag a small utility or co-op sees when it shops for a microreactor, and for a co-op like Hank’s, that difference is what decides whether a reactor ever makes it onto a board agenda at all.
What to Watch Next
This builds on other progress in thorium fuel research, including the ANEEL fuel design that recently cleared a key reactor test. Together, these efforts point toward a fuel cycle that’s cheaper, safer, and less reliant on scarce uranium supply chains, a shift covered in more depth in our overview of the state of nuclear fuel supply in 2026.
Neither LLNL nor Ampera has released a funding figure or public timeline for THUNDER. But pairing a national lab’s materials science with a startup’s push toward vertical fuel integration tends to move fast. If the droplet-jetting process scales the way PowderJet’s earlier results suggested it could, thorium TRISO fuel gets meaningfully closer to showing up in commercial reactors rather than just test facilities, and closer to a price tag a rural co-op can actually sign off on.
Source: ANS Nuclear Newswire