Originally an acronym for Safety Control Rod Axe Man, a term used to refer to the person assigned to the duty of dropping the boron control rods into the "pile" at the University of Chicago in case of emergency. This task was accomplished by cutting the supporting ropes with an axe and allowing the rods to drop into the core by natural gravitational forces.
Unclear, conflicting sources are probably backronyms.
- The emergency shutdown device of a nuclear reactor, originally specifically by insertion of one or more safety control rods.
- An activation of the emergency shutdown of a nuclear reactor.
- In a more general sense, an emergency shutdown.
- To use the Safety Control Rod Actuator Mechanism, or other similar safety devices, of the nuclear reactor
- By generalization, to use an emergency shutdown