Scram as the original and mostly likely accurate basis for the use of scram in the technical context. A persistent alternative explanation posits that scram is an acronym for 'safety control rod axe man', which was supposedly coined by Enrico Fermi when the world's first nuclear reactor was built under the spectator seating at the University of Chicago's Stagg Field. It could also stand for "Safety Control Rods Activation Mechanism" or "Control Rods Actuator Mechanism". Both of these are probably backronyms from the original, non-technical usage. In any reactor, a SCRAM is achieved by inserting large amounts of negative reactivity mass
Enrico Fermi Nuclear Power Plant (Italy) Enrico Fermi Nuclear Power Plant (Italy) Enrico Fermi Nuclear Power Plant was a nuclear power plant at Trino (often referred to as ‘Trino Vercellese’, meaning ‘Trino in the Province of Vercelli’), in north-west Italy. Consisting of one 260 megawatt pressurized water reactor (PWR) from the vendor Westinghouse Electric Corporation, it operated from 1964 until 1990. Trino was in 1964 the third ever commercially operated PWR worldwide, and it had the second highest megawatt-capacity of them. It was closed down following the Italian nuclear power referendum, 1987. The experimental enrichment plant, EUREX, near the power plant, was closed down in 1984.