Oak Ridge National Laboratory has been chosen as the site of an experimental facility to test materials that would withstand the harsh conditions of the plasmas created in fusion devices, which, researchers hope, could eventually provide carbon-free energy to people around the world.

The proposed facility, the Materials Plasma Exposure Experiment facility, or MPEX, has an estimated cost range between $87 million and $175 million. It would be in an existing facility in an area at ORNL known as the Energy Systems Test Complex.

Fusion devices would use the same reactions that power the sun. Temperatures inside a fusion reactor could reach millions of degrees.

Scientists are studying materials that could withstand the conditions inside fusion reactors by exposing them to prototypical plasma conditions. Plasma, the heated matter created in a fusion device, has high-energy neutrons, electrons, and ions. MPEX would study materials that face the plasma. Finding materials capable of withstanding the harsh environment remains a major hurdle to using fusion to produce energy.

A critical decision for the MPEX facility was completed in early February by the U.S. Department of Energy. ORNL is a DOE Office of Science lab. The critical decision, CD-1, is the second step in the five-step process that DOE uses to manage projects. The CD-1 decision included an alternative selection and a cost range.