The signature nuclear fusion experiment at the Princeton Plasma Physics Lab is expected to relaunch this summer after being shuttered for upgrades for about three years.


When it reopens, the reactor there will be the most powerful of its kind in the world, lab directors say.

"We expect to start up probably toward the end of June. We'll do the initial tests that will get us toward research operations, and (research) will start later in the summer, let's say August time frame, maybe mid-September," said Adam Cohen, chief operating officer for the lab.

The National Spherical Torus Experiment, also known as NSTX, is a plasma in the shape of a cored apple heated to between 50 million and 100 million degrees.

The experiment's $94 million upgrade bought a stronger magnet for the plasma's nuclear reactor and a second neutral beam accelerator to heat plasma even further.

"By doubling the current that flows in the plasma from 1 million to 2 million amps, and by quintupling the amount of time that we hold the plasma in place, we're going to get decisive information on whether this approach to fusion energy is feasible or not," said lab director Stewart Prager.

The Princeton Plasma Physics Lab runs the plasma experiment for the U.S. Department of Energy.

Researchers there are working to confine and control very hot plasma, a substance likened to the center of the sun, in magnetic force fields.

If it works, the heat from nuclear fusion reactions in the plasma could then be converted to electricity.

An earlier version of this article misspelled Stewart Prager's name.