I think you missed some news https://www.pbs.org/newshour/world/un-nuclear-watchdogs-safe... While they managed to avoid shooting directly at one of them, shelling the area wasn't uncommon and it's a bit up to luck that there were no mistakes.
* regular artillery shells, bunker busing is a different story
* as long as materials behave as expected, there are no existing cracks, ...
** ignoring secondary problems like vibrations misaligning elements, damage to other materials resulting in controller failures, damage to cooling system, injuries to staff not being able to respond to emergencies, ...
Sure, they should not be affected. They're also designed not to fail, and yet.