Years ago I worked with a millwright on a refueling outage at a nearby nuclear plant. During our two week training before beginning work, they warned us that there were about 2400 different things which could trigger an automatic shutdown and the resultant steam dump. Most were very minor.
However, they said that the steam dump would sound like a 747 landing right on top of you.
Like a misplaced jumper in a motor control center circuit in system that supposedly had nothing to do with reactor systems.
Emergency shutdowns can be unstable, just ask the operators at TMI.