At Oak Ridge, in the 1970s, the prospect of fusion power was strongly considered, sparking research at ORNL. A tokamak called ORMAK, made operational in 1971, was the first tokamak to achieve a plasma temperature of 20 million Kelvin. After the success of the fusion experiments, it was enlarged and renamed ORMAK II in 1973; however, the experiments ultimately failed to lead to fusion power plants.

The inside of ORMAK, an early tokamak, was gold plated for reflectivity