Fusion is still vapourware. For it to ever be viable outside a few niches, it will have to beat fission in price, because it will probably share many characteristics with fission plants (high capital costs, low cost of fuel, radioactive waste, huge plants).
Fusion somehow ended up being branded as the future of energy. But the prospects aren't looking good so far. Fission plants are probably already too expensive to have much of a future.
http://ecolo.org/documents/documents_in_english/Rickover.pdf
If a fission reactor is insuffciently cooled (due do the cooling system getting destroyed by attack or natural causes, cf the Fukushima Daiichi nuclear disaster), the reaction will continue, the core can melt and breach containment.
If a (plasma-based) fusion reactor gets damaged, the plasma will dissipate and the reaction will stop.
[1] diffen.com/difference/Nuclear_Fission_vs_Nuclear_Fusion