Honestly, does ANYBODY do that on large systems? With all the pressing and underfunded maintenance work and routine upgrades, who could ever find the budget to do a comprehensive review of the original design? I worked in lots of old fossil power plants at the beginning of my career. The best we could do was identify areas of possible incident failure and fix them before they failed during annual or semiannual planned maintenance outages.
My experience in the nuclear industry is that the original design is usually sound, and if anything over-designed. Where you get into trouble is increasing capacity or adding features without reassessing the original design assumptions. In addition, deferring manintenence due to budget or schedule always bites your behind.