Lawrence Livermore National Laboratory has signed a strategic R&D partnership with Florida-based startup Ampera to co-develop TRISO nuclear fuel with thorium-232 kernels, in a project the pair are calling THUNDER — for Thorium Unimodal Droplet Ejection for Reactors.
Why thorium, and why now
Ampera and LLNL announced the partnership on August 27. TRISO — for tri-structural isotropic — particles are the pinhead-sized fuel spheres that many next-generation advanced reactors are built around, wrapped in ceramic and carbon coatings that trap fission products even at very high temperatures. Almost every TRISO program on the market today uses uranium kernels; the THUNDER effort is aimed at swapping those out for thorium-232, which LLNL notes is "abundant, produces a less persistent waste stream, and is more difficult to weaponize."
Liquid-metal jetting inherited from PowderJet
The manufacturing tech at the core of THUNDER is a liquid-metal droplet-on-demand jetting system that LLNL research engineer Viktor Sukhotskiy and his team built during the lab's 2023 PowderJet project. The idea is to produce highly uniform, spherical Th-232 kernels at scale — one of the persistent bottlenecks in commercialising advanced-reactor fuel. "Working with Ampera gives us the opportunity to apply joint expertise to a challenging nuclear fuel problem while also continuing to mature liquid metal jetting as an advanced manufacturing technology," Sukhotskiy said.
Vertically integrating a fuel supply
Founded in 2025, Ampera is designing compact subcritical nuclear energy systems and has spent the summer building out the manufacturing side of its stack: a June announcement set up an Australian subsidiary to secure thorium feedstock, and a July milestone saw the company 3D-print a full-scale silicon-carbide model of its spherical gyroid reactor core. CEO Brian Matthews called the LLNL deal "fundamental to Ampera's strategy" of vertically integrating fuel supply and cutting supply-chain risk.
The tie-up adds to a busy summer for TRISO in the US, including Antares Nuclear's multi-year TRISO supply agreement with Standard Nuclear and DOE-funded expansions of TRISO-X in Tennessee.
Reporting based on coverage from the ANS Nuclear Newswire (Aug. 27, 2026), Ampera/LLNL PR Newswire release and World Nuclear News.