Fusion researchers are increasingly turning to tungsten for plasma-facing components in tokamaks and stellarators. However, under intense plasma heat, tungsten atoms can sputter from the walls and enter the plasma. Excess tungsten in the plasma can cool it, making sustained fusion reactions more challenging.

PPPL researchers, including Florian Effenberg, have experimental and modeling results suggesting that sprinkling boron powder into the tokamak can address this issue. Effenberg led the development of a new computer modeling workflow that shows boron powder can be applied effectively from a single location, ensuring uniform coverage. The framework combines plasma behavior, boron particle dynamics, and wall interactions to optimize boron injection strategies.

Experiments in tungsten-walled tokamaks in Germany, China, and the U.S. showed reduced tungsten sputtering with boron injection. Developed in collaboration with ITER and Oak Ridge, the injection system could operate in real-time, control boron quantities, and limit tritium retention. The research now focuses on scaling the approach to ITER’s tungsten walls.

More information about the new modeling workflow can be found here: F. Effenberg et al, “Integrated modeling of boron powder injection for real-time plasma-facing component conditioning”, Nuclear Materials and Energy 42 (2025) 101832 https://doi.org/10.1016/j.nme.2024.101832.