I saw your but allow me to respond

Both were not fusion. the fusion process does not leave the highly toxic and radioactive waste, and uses chemically harmless compounds.

And while the reaction itself is as hot as the core of the sun, the amount of material that reaches those temperatures is small. So even if the whole process would go out of hand, it would not be comparable to a thermonuclear weapon..

Furthermore, the problem with chernobyl was not the physical demolition (which was limited to the site) but the escape of large quantities of highly radioactive and toxic material that spread across asia and europe.
Fusion does not have that problem. If the worst comes to the worst, you'll lose the site and the energy input on the grid, but that is where it stops.

Ok you might have to deal with the demons from hell escaping to our world through the dimensional rip, but that is what double barreled shotguns are for.