That non-scientific media reporting on scientific achievements is hilarious to read?
I have no idea where they got that the "mass melted the core of the nuclear fusion chamber". That just didn't happen, and can't actually happen. The plasma in the Tokamak chamber is miniscule and will cool off as soon it hits a wall in case the magnetic containment failed. Which is probably what happened after 102s, as Tokamaks can (in their basic configuration without neutral beam injection) only work in a pulsed manner.
But it's a pretty big feat in Tokamak development, I'm very excited about that. The german Stellarator Wendelstein 7X is also starting to work, btw., having recently achieved a hydrogen plasma. That one's going to be interesting, because Stellarators can work continously by design, and Wendelstein 7X, despite not designed to produce power, is a big step towards achieving a viable fusion power plant as it is a testbed for all the complications that come with the Stellarator design.