I am sure many people have wondered what will happen when a Nuclear plant is hit by bombs.
I believe we will be finding out soon.
Nothing. All the components of either a uranium or plutonium bomb have to be in a very precise geometric relationship for a nuclear "boom" to happen. Said precise geometry is destroyed by the leading edge of the shockwave from the attacking weaponry.
The only way this is avoidable is if the weapon is equipped with a radiological "dead man switch" which will automatically trigger the bomb with detection of a high pulse of gamma radiation (which, moving at the speed of light, preceeds the shockwave, which only moves at about the speed of sound).
But then your own bomb is helping destroy the facility you want NOT to be destroyed.
And, of course the "deadman switch" only works if the attacking weaponry is itself nuclear.....chemical explosions won't trigger....all their effect arrives at the speed of the shockwave.