In case you weren’t aware, the “safety control rod ax man” thing is aprocryphal and almost certainly not reflective of the origins of the term.

It's one of the more truthy backronyms. There was an actual ax man with an ax whose job was to cut a rope to let loose the control rods, and they did use the (existing, apt) word, scram, for the emergency procedure: https://en.wikipedia.org/wiki/Scram

Simpson's?