We don't have any technical defense against institutional failure. In some places and times there are cultural defenses, but those are often seen to erode.
The best defense is not to need any. There is much less need to defend against institutional failure in the case of renewables, because the technical failures to guard against have limited impact, well constrained in cost, time and space.
Honestly, I’m not well educated on Chernobyl’s mode of failure or political incentive structures. I’d probably agree with your implication that if procedures can’t be followed consistently/successfully than that is exactly an engineering failure, but as I said I do not know this circumstance
What do you call Chernobyl? A socialistic failure driven by inept bureaucracy and central planning?