Fission and fusion are fundamentally different in the way they work. If a fission reaction goes out of control, it can continue releasing enormous amounts of

Fission and fusion are fundamentally different in the way they work. If a fission reaction goes out of control, it can continue releasing enormous amounts of energy for days or even weeks, because it's based around releasing radioactive energy stored in the nuclear fuel. Fusion OTOH is fusing together atoms of fuel that are relatively benign on their own - fusion is only possible at the high temperatures inside the reactor. I'm no expert on the physics, but AFAIK as soon as a fusion reactor is breached the conditions needed to sustain the reaction will quickly disappear and the reaction will almost immediately stop.