Scientists meeting from around the world in a fusion energy conference last week proclaimed the recent success of a University of Illinois-led innovation for fusion reactors.

David Ruzic, professor of nuclear, plasma, and radiological engineering at the University of Illinois at Urbana-Champaign, presented results on “Lithium-Metal Infused Trenches: A New Way to Remove Diverter Heat Flux,” at the 24th International Atomic Energy Agency (IAEA) Fusion Energy Conference held in San Diego, California. Ruzic’s paper reflected success from an experiment conducted on October 11, 2012 on an HT-7 Tokamak (experimental superconducting nuclear fusion) reactor in Hefei, China.

Later, selected to summarize the conference’s fusion technology and power plant designs contributions, Stanley Milora of Oak Ridge National Laboratory noted that the Illinois group’s experiment “is installed on HT-7 in China and is working very, very satisfactorily.”

The success in China is the culmination of a decade of work aimed at making fusion reactors more economical.

Ruzic and his students in the Center for Plasma Material Interactions (CPMI) designed a method for molten lithium to self-circulate along the surface of a fusion reactor’s diverter, where excess heat is collected and removed. Such an innovation, Ruzic believes, could reduce the size of a fusion reactor’s radius by a third, while allowing it to produce the same volume of energy.

“We’re looking at a factor of 10 in cost reductions, at least,” Ruzic said.

The concept, known as LiMIT (Lithium/Metal Infused Trenches), previously was successfully conducted in CPMI laboratories. Ruzic believes the success in China shows that LiMit works on an actual fusion device as well as in the laboratory.

“It did flow – at the rate we predicted,” Ruzic explained. “It did not cause any type of failure, and it even improved their energy confinement by 10 percent. Given that this was a small module and was not the main ‘limiter,’ it is very likely that a larger LiMITS closer to the plasma would have improved confinement and other parameters by an even greater degree.”

This demonstration of a flowing molten lithium limiter in an actual major fusion device is a first and a major breakthrough. In addition to the Chinese, the U.S. Department of Energy has been interested in the work, and had awarded a $600,000 grant to fund experiments in the CPMI laboratories.

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Contact: David Ruzic, Department of Nuclear, Plasma, and Radiological Engineering, 217/333-0332.

Writer: Susan Mumm, editor/alumni affairs coordinator, Department of Nuclear, Plasma, and Radiological Engineering, 217/244-5382.