US fusion facility to test powerful materials under extreme heat flux

The Tennessee Valley Authority’s Bull Run Energy Complex in Tennessee is preparing to host a new high-heat flux (HHF) testing facility, a collaborative project involving the Department of Energy’s Oak Ridge National Laboratory (ORNL), Type One Energy, and the University of Tennessee, Knoxville (UT). Scheduled for completion by the end of 2027, the facility will simulate the extreme heat flux conditions found in fusion reactors—targeting steady-state heat loads exceeding 10 megawatts per square meter—to test plasma-facing components (PFCs) that must endure intense operational stresses. This will be the second such facility in the U.S. and the most powerful, uniquely featuring pressurized helium gas cooling, which is favored in several domestic fusion reactor designs due to helium’s chemical stability under fusion conditions. The Bull Run site, already home to Type One Energy’s Infinity One stellarator testbed, is envisioned as a fusion development campus integrating research from ORNL, UT, and industry partners. ORNL