Another nuclear fusion reactor, and this one won't be producing power either. It's only for running scientific experiments.
Fusion reactors, in contrast to fission reactors, don't produce any radioactive byproduct. But the technology, though possible in theory, never worked in any man made machine.
I had high hopes in the 80s that humans would be producing fusion power by 2020, but that isn't going to happen. Another failed future prediction.