ORNL, Type One partner to advance fusion fuel cycle

The agreement outlines the use of four ORNL inventions supporting the design and operation of cryogenic pellet fuelling systems. Cryogenic pellet fuelling forms solid pellets of hydrogen at temperatures just a few degrees above absolute zero and injects them at high speed into a fusion plasma. ORNL says it is more effective at fuelling the core of a plasma than other methods, such as gas puffing, and contributes to improved plasma performance.

According to ORNL, the licensed technologies address a gap in fuel performance, containment and recirculation challenges by providing a novel extrusion system that can produce pellets at rates appropriate for reactor operations. The system is expected to efficiently and safely provide flexible continuous plasma fuelling.

Fusion reactors that run on deuterium and tritium must be continuously refuelled to replace ions consumed in the reaction and lost from the confining magnetic fields. "While deuterium is relatively abundant and can be handled with conventional equipment, tritium's scarcity and radioactivity present unique challenges for reprocessing and containment, and no current pellet injectors are able to produce pellets at required rates," ORNL said.

The licensed technologies are: a tritium-compatible cryogenic pellet gas gun (which minimises stress-induced failures for reliable, long-term operation in fusion environments); a tritium-compatible cryogenic screw extruder for plasma energy pellet injection (for maintaining hermetic containment during continuous pellet production); a pressure relief device for cryogenic fusion fuels (to provide overpressure protection); and a solid conveyance with single phase change method for cryogenic extrusion recirculation (for creating a more efficient, closed-loop fuelling process).

"Together, these technologies form a key part of the lab's longstanding leadership in fusion fuelling science and will play an important role in the creation of high-performance plasmas in next-generation fusion devices," ORNL said.

Type One Energy, based in Oak Ridge, Tennessee, has previously worked with ORNL on several major technology collaborations, including a recently-announced high-heat flux test facility and a joint project in the Innovation Network for Fusion Energy (INFUSE) programme.

"Type One Energy is a valued partner in advancing fusion energy research," said ORNL Director Stephen Streiffer. "This licence is an exciting next step in our partnership, moving our fuelling research out of the lab and into application, and we look forward to seeing these technologies contribute to the future of fusion energy."

"Our continuing collaboration with Oak Ridge National Laboratory is accelerating the commercialisation of fusion energy," said John Canik, Chief Science and Engineering Officer at Type One Energy. "Fuelling the fusion reaction with high repetition and high reliability is one of the most essential technologies for continuous generation of fusion power."

Type One Energy is developing a stellarator fusion reactor - different to a tokamak fusion reactor such as the Joint European Torus in the UK or the Iter device under construction in France. A tokamak is based on a uniform toroid shape, whereas a stellarator twists that shape in a figure-8. This is intended to get round the problems tokamaks can face when magnetic coils confining the plasma are necessarily less dense on the outside of the toroidal ring.

Type One Energy's Project Infinity - which encompasses the Infinity One prototype and workforce training centre together with the 350 MWe Infinity Two fusion power plant - will proceed in several phases at Tennessee Valley Authority's Bull Run site. The first phase of the project, deployment of Infinity One operated by Type One Energy, is scheduled for commissioning and startup in 2029.