If the assumption is that the major world powers don't cooperate enough to tackle a global existential crisis then we're fucked even without someone bombing a nuclear power plant.

Nuclear is currently the only viable option for buying enough time to address all the other negative consequence of 2C+ of warming. All the other plans currently on the table are accelerating us towards 3C of warming and that essentially means human civilization as we now know it is over.

They're not "nuke plants". "nuke" is a word that means "nuclear weapons".

Secondly, they're heavily surrounded by highly reinforced concrete with extremely high levels of security. The furthest any activist with a bomb belt could get is jumping a fence and getting immediately caught. Even if they could drive a truck through the front gate and set off a car bomb, they're not getting through the extremely thick concrete.

if we are in a position where civilian targets are getting bombed we have other problems. not mention in said "war" if we are reliant on green energy we will certainly lose to whoever bombed our power plants.