Cold Fusion (in physics, not in web development) became a taboo expression nineteen years ago after Martin Fleischmann and Stanley Pons were unable to replicate their experiment that supposedly produced fusion in a glass jar at room temperature. And, since nobody else was able to duplicate the results, cold fusion has since become a synonym for pseudo-science. But that may be about to change.
Jon Cartwright of the physicsworld blog reports that Yoshiaki Arata, a retired physics professor at Osaka University and his partner, Yue-Chang Zhang, have demonstrated what appears to be a repeatable experiment that involves forcing deuterium into an evacuated cell containing a sample of palladium dispersed in zirconium oxide. According to Arata, the deuterium is absorbed by the sample in large enough amounts to force the deuterium nuclei to become close enough to fuse.
It's way, way too early to say whether or not these results have any validity, as (like with Fleischmann and Pons) they will need to be replicated by several other teams and the results fully understood. Additionally, the temperature of the sample only rose to about 70°C. While that is significant and notable, it is not enough to produce steam to turn a turbine, so more work would need to be done.
Also, there appears to be some debate as to whether the heating was actually caused by fusion or whether it was purely chemical. However, if deuterium is fed into the sample and helium comes out, I don't see any other process that could explain that. But more research will reveal the truth.