to shut down (a nuclear reactor) quickly, as in an emergency.
the rapid shut down of a nuclear reactor, as in an emergency.
An emergency shutdown (trip) of a nuclear reactor, done by driving control rods to the bottom of the core using springs. A term left over from the 1940s when the primitive lab reactors had a control rod hanging by a rope. An emergency trip would be initiated by the Safety Control Rod Ax Man (SCRAM).