Watch as solid hydrogen is extruded to feed German stellarator

August 29, 2025, 12:02PMNuclear News
A plastic pellet replica alongside a dime and the tool that cuts each pellet from a solid hydrogen filament. (Photo: Larry Baylor/ORNL)

In May, the Wendelstein 7-X stellarator in Greifswald, Germany, concluded an experimental campaign by sustaining a plasma with a high triple product for 43 seconds. The machine far surpassed its own previous performance with a value that the Max Planck Institute for Plasma Physics (IPP) says “exceeds previous tokamak records for long plasma durations”—in part because of a fuel pellet injection system developed by researchers at Oak Ridge National Laboratory.

Watch ORNL’s video of that fuel pellet injection system—in use since September 2024—as it extrudes a column of frozen hydrogen and then cuts individual 3.2-millimeter-long pellets. The process, which takes just half a millisecond, was captured in slow motion by ORNL engineer Steve Meitner.